WO2023074468A1 - Adhesive agent composition, adhesive agent, adhesive sheet, and surface protection film - Google Patents

Adhesive agent composition, adhesive agent, adhesive sheet, and surface protection film Download PDF

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Publication number
WO2023074468A1
WO2023074468A1 PCT/JP2022/038756 JP2022038756W WO2023074468A1 WO 2023074468 A1 WO2023074468 A1 WO 2023074468A1 JP 2022038756 W JP2022038756 W JP 2022038756W WO 2023074468 A1 WO2023074468 A1 WO 2023074468A1
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Prior art keywords
meth
pressure
sensitive adhesive
acrylate
weight
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PCT/JP2022/038756
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French (fr)
Japanese (ja)
Inventor
裕充 森下
匡哉 柴野
真人 山形
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日東電工株式会社
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Priority to JP2023556345A priority Critical patent/JPWO2023074468A1/ja
Priority to CN202280070236.5A priority patent/CN118119682A/en
Priority to KR1020247016651A priority patent/KR20240093800A/en
Publication of WO2023074468A1 publication Critical patent/WO2023074468A1/en

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    • C—CHEMISTRY; METALLURGY
    • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
    • C09J—ADHESIVES; NON-MECHANICAL ASPECTS OF ADHESIVE PROCESSES IN GENERAL; ADHESIVE PROCESSES NOT PROVIDED FOR ELSEWHERE; USE OF MATERIALS AS ADHESIVES
    • C09J11/00—Features of adhesives not provided for in group C09J9/00, e.g. additives
    • C09J11/02—Non-macromolecular additives
    • C09J11/06—Non-macromolecular additives organic
    • C—CHEMISTRY; METALLURGY
    • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
    • C09J—ADHESIVES; NON-MECHANICAL ASPECTS OF ADHESIVE PROCESSES IN GENERAL; ADHESIVE PROCESSES NOT PROVIDED FOR ELSEWHERE; USE OF MATERIALS AS ADHESIVES
    • C09J133/00—Adhesives based on homopolymers or copolymers of compounds having one or more unsaturated aliphatic radicals, each having only one carbon-to-carbon double bond, and at least one being terminated by only one carboxyl radical, or of salts, anhydrides, esters, amides, imides, or nitriles thereof; Adhesives based on derivatives of such polymers
    • C09J133/04—Homopolymers or copolymers of esters
    • C09J133/06—Homopolymers or copolymers of esters of esters containing only carbon, hydrogen and oxygen, the oxygen atom being present only as part of the carboxyl radical
    • C—CHEMISTRY; METALLURGY
    • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
    • C09J—ADHESIVES; NON-MECHANICAL ASPECTS OF ADHESIVE PROCESSES IN GENERAL; ADHESIVE PROCESSES NOT PROVIDED FOR ELSEWHERE; USE OF MATERIALS AS ADHESIVES
    • C09J7/00—Adhesives in the form of films or foils
    • C09J7/30—Adhesives in the form of films or foils characterised by the adhesive composition
    • C09J7/38—Pressure-sensitive adhesives [PSA]

Definitions

  • the present invention relates to an adhesive composition, an adhesive, an adhesive sheet and a surface protection film.
  • pressure-sensitive adhesives also called pressure-sensitive adhesives; the same shall apply hereinafter
  • adhesives are widely used in the form of adhesive sheets for purposes such as bonding of parts and surface protection.
  • the pressure-sensitive adhesive is formed from, for example, a pressure-sensitive adhesive composition containing an acrylic polymer and a cross-linking agent.
  • Patent Documents 1 to 3 Prior art documents disclosing this type of prior art include Patent Documents 1 to 3.
  • a pressure-sensitive adhesive sheet having a pressure-sensitive adhesive layer on one surface of a substrate is also preferable as a surface protective film that prevents surface damage (scratches, stains, corrosion, etc.) during processing or transportation of various articles. It's being used.
  • a surface protection film that is peeled off (re-peeled) from the object to be protected (adherend) after achieving the purpose of protecting the object to be protected the adhesive does not leave adhesive residue on the adherend. Light releasability is required so that it can be peeled off smoothly.
  • the peeling speed of re-peeling at the actual work site may be low or high. If the peeling force varies greatly due to the difference in peeling speed, the peeling workability is affected and the peeling work is not efficient. For this reason, it is required that the pressure-sensitive adhesive used in a mode of use in which it is re-peeled from the adherend does not change its peeling force significantly depending on the difference in peeling speed. Specifically, the pressure-sensitive adhesive is required to exhibit light releasability at least in low-speed detachment, and to keep the release force low even in high-speed detachment (suppression of release force increase in high-speed detachment). be done.
  • the present invention was created in view of the above circumstances, and is a pressure-sensitive adhesive composition capable of forming a pressure-sensitive adhesive that can achieve light release properties in low-speed release and suppression of increase in release force in high-speed release.
  • a pressure-sensitive adhesive sheet that can achieve light release properties in low-speed release and suppression of increase in release force in high-speed release.
  • Another related object is to provide a pressure-sensitive adhesive formed from the pressure-sensitive adhesive composition, a pressure-sensitive adhesive sheet having the pressure-sensitive adhesive, and a surface protection film comprising the pressure-sensitive adhesive sheet.
  • a pressure-sensitive adhesive composition containing an acrylic polymer and an epoxy-based cross-linking agent.
  • the acrylic polymer is a polymer of a monomer component containing an alkyl (meth)acrylate having a linear alkyl group having 5 to 18 carbon atoms at the ester end.
  • the monomer component further contains (meth)acrylic acid.
  • a cross-linking agent e.g., an epoxy-based cross-linking agent
  • the cross-linking reaction with a cross-linking agent proceeds favorably, increasing curability and improving light release properties in low-speed release. It is easy to form a pressure-sensitive adhesive that can suppress an increase in peel strength during high-speed peeling and an increase in adhesive strength over time.
  • the alkyl (meth)acrylate having a linear alkyl group having 5 to 18 carbon atoms at the ester end includes n-heptyl acrylate (HpA).
  • HpA is preferably used as the alkyl (meth)acrylate having a linear alkyl group having 5 to 18 carbon atoms at the ester end.
  • a pressure-sensitive adhesive formed from any of the pressure-sensitive adhesive compositions disclosed herein is provided.
  • Such an adhesive exhibits light release properties in low-speed peeling and suppresses the increase in peel force in high-speed peeling. Easy to peel off regardless of the peeling speed.
  • the adhesive has a gel fraction of 70% or more.
  • a pressure-sensitive adhesive having a gel fraction of 70% or more is less likely to cause deformation or damage such as dents due to external force during production, and less likely to cause changes in appearance.
  • Such a pressure-sensitive adhesive tends to form a pressure-sensitive adhesive sheet having a smooth surface.
  • a PSA with a high gel fraction is preferable because it exhibits light release properties during low-speed release, suppresses an increase in release force during high-speed release, and suppresses an increase in adhesive strength over time.
  • a pressure-sensitive adhesive sheet having a pressure-sensitive adhesive layer made of any pressure-sensitive adhesive disclosed herein is provided.
  • the pressure-sensitive adhesive sheet disclosed herein exhibits light release properties in low-speed peeling and suppresses the increase in peel force in high-speed peeling, so regardless of the peel speed Easy to peel off. Therefore, it is suitable as a surface protection film. After the surface protective film is attached to the object to be protected, it is usually peeled off (re-peeled) from the object to be protected when the protective purpose is achieved.
  • a pressure-sensitive adhesive sheet having a pressure-sensitive adhesive layer with a gel fraction of 70% or more is provided.
  • the pressure-sensitive adhesive layer is formed from a pressure-sensitive adhesive composition containing an acrylic polymer and a cross-linking agent, and the acrylic polymer is an alkyl ( It is a polymer of monomer components containing meth)acrylate.
  • a pressure-sensitive adhesive layer having a gel fraction of 70% or more is less likely to be deformed or damaged, such as dents due to external force, during production, and is less likely to change in appearance.
  • a pressure-sensitive adhesive sheet having such a pressure-sensitive adhesive layer tends to have a smooth surface, and is preferable because, for example, when an adherend is inspected through the pressure-sensitive adhesive sheet and configured as a transparent pressure-sensitive adhesive sheet, highly accurate inspection is possible.
  • the pressure-sensitive adhesive sheet tends to exhibit light release properties in low-speed peeling, suppress an increase in peel force in high-speed peeling, and be capable of suppressing an increase in adhesive strength over time.
  • the cross-linking agent includes an epoxy-based cross-linking agent.
  • the monomer component further contains (meth)acrylic acid.
  • the surface protective film has an initial high-speed adhesive strength of 3.0 N/25 mm or less measured at a tensile speed of 30 m/min after aging in a 50°C environment for 3 days.
  • a surface protective film that satisfies this property has a low peeling force even if it is peeled off from an object to be protected, which is an adherend, at a high speed.
  • FIG. 1 is a cross-sectional view schematically showing the configuration of a pressure-sensitive adhesive sheet according to one embodiment
  • the term “adhesive” refers to a material that exhibits a soft solid (viscoelastic) state in a temperature range around room temperature and has the property of easily adhering to an adherend under pressure, as described above. .
  • the adhesive as used herein generally has a complex tensile elastic modulus E * (1 Hz) as defined in "C. A. Dahlquist, “Adhesion: Fundamental and Practice", McLaren & Sons (1966), p. 143". It may be a material having properties satisfying ⁇ 10 7 dyne/cm 2 (typically, a material having the above properties at 25°C).
  • biomass-derived carbon means carbon derived from biomass materials, that is, materials derived from renewable organic resources (renewable carbon).
  • the biomass material is typically a material derived from biological resources (typically photosynthetic plants) that can be sustainably reproduced in the presence of sunlight, water, and carbon dioxide.
  • materials derived from fossil resources that are depleted by use after mining are excluded from the concept of biomass materials here.
  • the biomass-carbon ratio of the pressure-sensitive adhesive composition and pressure-sensitive adhesive that is, the ratio of biomass-derived carbon to the total carbon contained in the pressure-sensitive adhesive composition and pressure-sensitive adhesive, is the carbon isotope with a mass number of 14 measured according to ASTM D6866. can be estimated from body content.
  • (Meth)acrylic monomer refers to a monomer having at least one (meth)acryloyl group in one molecule.
  • (meth)acryloyl is a generic term for acryloyl and methacryloyl. Therefore, the concept of a (meth)acrylic monomer as used herein can include both a monomer having an acryloyl group (acrylic monomer) and a monomer having a methacryloyl group (methacrylic monomer).
  • (meth)acrylic acid is meant to comprehensively refer to acrylic acid and methacrylic acid.
  • the adhesive composition disclosed here contains an acrylic polymer.
  • “acrylic polymer” refers to a polymer derived from a monomer component containing more than 50% by weight of (meth)acrylic monomer.
  • the content of the (meth)acrylic monomer in the monomer component is preferably 70% by weight or more, and may be 80% by weight or more. In some aspects, the content of the (meth)acrylic monomer in the monomer component may be 90% by weight or more, 95% by weight or more, or 100% by weight.
  • the proportion of the (meth)acrylic monomer in the total monomer components may be, for example, less than 99% by weight, may be less than 95% by weight, or may be less than 93% by weight. It may be less than weight percent.
  • the monomer component constituting the acrylic polymer is an alkyl (meth)acrylate having a linear alkyl group having 5 to 18 carbon atoms at the ester end (hereinafter also referred to as “C 5-18 linear alkyl (meth)acrylate”).
  • C 5-18 linear alkyl (meth)acrylate One of the features is to include Although not particularly limited, the use of alkyl (meth)acrylates with relatively long linear alkyl groups of 5 to 18 carbon atoms increases curability based on the entanglement and orientation of the alkyl groups, and adhesion during low-speed peeling. It is thought that the force is kept low and the increase in adhesive strength during high-speed peeling is suppressed.
  • the above C 5-18 linear alkyl (meth)acrylate can also be represented by the following formula (1).
  • CH2 C( R1 ) COOR2 (1)
  • R 1 in the above formula (1) is a hydrogen atom or a methyl group.
  • R 2 is a linear alkyl group having 5 to 18 carbon atoms.
  • the number of carbon atoms in the straight-chain alkyl group of the C 5-18 straight-chain alkyl (meth)acrylate is preferably 14 or less, more preferably 12 or less, still more preferably 11 or less, and particularly preferably 10 or less, from the viewpoint of adhesive properties. (eg 9 or 8 or less).
  • the number of carbon atoms is preferably 6 or more, more preferably 7 or more, from the viewpoint of effectively exhibiting the effect and properties of making the alkyl group longer.
  • C 5-18 linear alkyl (meth)acrylates include n-pentyl (meth)acrylate, n-hexyl (meth)acrylate, n-heptyl (meth)acrylate, n-octyl (meth)acrylate, n -nonyl (meth)acrylate, n-decyl (meth)acrylate, n-undecyl (meth)acrylate, n-dodecyl (meth)acrylate, n-tridecyl (meth)acrylate, n-tetradecyl (meth)acrylate, n-pentadecyl (Meth)acrylate, n-hexadecyl (meth)acrylate, n-heptadecyl (meth)acrylate, n-octadecyl (meth)acrylate and the like.
  • the C 5-18 linear alkyl (meth)acrylates can be used sing
  • the proportion of the C5-18 straight-chain alkyl (meth)acrylate in the total monomer components is set according to the purpose of use, required properties, etc., and may be, for example, 1% by weight or more, preferably 10% by weight or more. , preferably 30% by weight or more, more preferably 50% by weight or more (for example, more than 50% by weight), may be 70% by weight or more, may be 80% by weight or more, may be 85% by weight or more, or may be 90% by weight % or more, 92% by weight or more, or 95% by weight or more.
  • the properties based on the C 5-18 linear alkyl (meth)acrylate can be effectively exhibited.
  • the proportion of C 5-18 linear alkyl (meth)acrylate in the total monomer components is, for example, less than 99% by weight. may be less than 98% by weight, less than 97% by weight.
  • the upper limit of the proportion of C 5-18 linear alkyl (meth)acrylate in the total monomer component may be 95% by weight or less from the viewpoint of obtaining the effect of using other monomers. , 75% by weight or less, 60% by weight or less, 50% by weight or less (for example, less than 50% by weight), or 30% by weight or less.
  • Alkyl (meth)acrylate having a chain alkyl group at the ester end contained as a monomer component of the acrylic polymer above C 5-18 straight chain accounts for the whole
  • the proportion of alkyl (meth)acrylate may be, for example, 1% by weight or more, suitably 10% by weight or more, preferably 30% by weight or more, more preferably 50% by weight or more (for example, more than 50% by weight). and may be 70% by weight or more, 80% by weight or more, 90% by weight or more, 95% by weight or more, or 99% by weight or more.
  • the above-mentioned chain alkyl group is a concept that includes linear and branched alkyl groups, and does not include cyclic alkyl groups called alicyclic.
  • the technology disclosed herein can be preferably practiced in a mode using an acrylic polymer having a monomer composition containing only C 5-18 linear alkyl (meth)acrylate as the chain alkyl (meth)acrylate. Therefore, the upper limit of the ratio of C 5-18 straight-chain alkyl (meth)acrylate to the whole chain alkyl (meth)acrylate is 100% by weight.
  • the ratio of C 5-18 straight chain alkyl (meth ) acrylates to the total chain alkyl (meth)acrylate is From the viewpoint of obtaining the effect of using (meth) acrylate, it may be 95% by weight or less, 75% by weight or less, 60% by weight or less, or 50% by weight or less (for example, less than 50% by weight). It may be 30% by weight or less.
  • the C 5-18 linear alkyl (meth)acrylates include one or more C 5-11 linear alkyl (meth)acrylates and one or more C 12-18 You may use together with a linear alkyl (meth)acrylate.
  • the ratio of the two to be used can be set according to the adhesive property, the action and properties based on the alkyl group of each monomer, and the like.
  • the proportion of C 5-11 linear alkyl (meth)acrylate in C 5-18 linear alkyl (meth)acrylate may be, for example, 1% by weight or more, 10% by weight or more, or 30% by weight.
  • C 5-11 linear alkyl (meth)acrylate in C 5-18 linear alkyl (meth)acrylate may be 99% by weight or less, may be 90% by weight or less, or may be 80% by weight. It can be below.
  • the above C 5-11 linear alkyl (meth)acrylate is an alkyl (meth) having a linear alkyl group having 10 or less carbon atoms (more preferably 9 or less, for example 8 or less, preferably 7) at the ester end.
  • Acrylates are preferably used.
  • the straight-chain alkyl group preferably has 6 or more carbon atoms.
  • n-heptyl (meth)acrylate is used as the C 5-18 linear alkyl (meth)acrylate.
  • n-heptyl (meth)acrylate the effects of the technology disclosed herein can be exhibited particularly favorably.
  • n-heptyl acrylate is particularly preferable from the viewpoint of adhesive properties.
  • the ratio of n-heptyl (meth)acrylate in the total monomer components is set according to the purpose of use, required properties, etc., and may be, for example, 1% by weight or more, preferably 10% by weight or more. is 30% by weight or more, more preferably 50% by weight or more (for example, more than 50% by weight), may be 70% by weight or more, may be 80% by weight or more, may be 85% by weight or more, or may be 90% by weight or more. , 92% by weight or more, or 95% by weight or more.
  • the proportion of n-heptyl (meth) acrylate in the total monomer components may be, for example, less than 99% by weight. It may be less than 98 wt%, or less than 97 wt%. In some other embodiments, the proportion of n-heptyl(meth)acrylate in the total monomer components is 95% by weight or less from the viewpoint of obtaining the effect of using various monomers other than n-heptyl(meth)acrylate. 75% by weight or less, 60% by weight or less, 50% by weight or less (for example, less than 50% by weight), or 30% by weight or less.
  • the ratio of n-heptyl (meth)acrylate to the total linear alkyl (meth)acrylate contained as a monomer component of the acrylic polymer may be, for example, 1% by weight or more, and is suitably 10% by weight or more. , preferably 30% by weight or more, more preferably 50% by weight or more (for example, more than 50% by weight), may be 70% by weight or more, may be 80% by weight or more, may be 90% by weight or more, or may be 95% by weight or more , or 99% by weight or more.
  • the technology disclosed herein can be preferably implemented in a mode using an acrylic polymer having a monomer composition containing only n-heptyl (meth)acrylate as the chain alkyl (meth)acrylate. Therefore, the upper limit of the ratio of n-heptyl (meth)acrylate to the total chain alkyl (meth)acrylate is 100% by weight. In some other embodiments, the ratio of n-heptyl (meth)acrylate to the total chain alkyl (meth)acrylate is 95% by weight from the viewpoint of obtaining the effect of using other chain alkyl (meth)acrylate. 75% by weight or less, 60% by weight or less, 50% by weight or less (for example, less than 50% by weight), or 30% by weight or less.
  • the monomer component constituting the acrylic polymer may contain an alkyl (meth)acrylate having a chain alkyl group with 19 or more carbon atoms at the ester end (chain alkyl (meth)acrylate with 19 or more carbon atoms). , may not be included.
  • the C19 or higher chain alkyl (meth)acrylates may be used singly or in combination of two or more.
  • the ratio of the C19 or higher chain alkyl (meth)acrylate to the total chain alkyl (meth)acrylate contained in the monomer component may be, for example, 90% by weight or less, 70% by weight or less, or 50% by weight.
  • the technique disclosed herein can be preferably implemented in a mode in which the monomer component does not substantially contain C19 or higher chain alkyl (meth)acrylate.
  • the monomer component is an alkyl (meth)acrylate having a biomass-derived alkyl group at the ester end (hereinafter also referred to as "biomass chain alkyl (meth)acrylate”) as the chain alkyl (meth)acrylate. .).
  • biomass chain alkyl (meth)acrylate a biomass-derived alkyl group at the ester end
  • the biomass chain alkyl (meth)acrylate is not particularly limited, and is, for example, an ester of a biomass-derived alkanol and a biomass-derived or non-biomass-derived (meth)acrylic acid.
  • biomass-derived alkanols include biomass ethanol, alkanols derived from plant sources such as palm oil, palm kernel oil, coconut oil, castor oil, and the like. When the number of carbon atoms in the biomass-derived alkanol is 3 or more, the alkanol may be linear or branched.
  • an ester of a biomass-derived alkanol and a non-biomass-derived (meth)acrylic acid is used as the biomass linear alkyl (meth)acrylate used to synthesize the acrylic polymer.
  • the greater the number of carbon atoms in the alkanol the more the number of biomass-derived carbons accounts for the total number of carbon atoms contained in the biomass chain alkyl (meth)acrylate, that is, the chain alkyl ( The biomass carbon ratio of meth)acrylate is increased.
  • the chain alkyl group derived from biomass has a large number of carbon atoms in order to reduce dependence on fossil resource-based materials.
  • the number of carbon atoms in the chain alkyl group that constitutes the chain alkyl (meth)acrylate is too large, it tends to be difficult to obtain adhesive properties such as adhesive strength. It can also be disadvantageous in terms of gender.
  • a biomass chain-like alkyl (meth)acrylate can be used for any of the alkyl (meth)acrylates.
  • a biomass chain alkyl (meth)acrylate is used as the C 5-18 straight chain alkyl (meth)acrylate
  • a biomass chain alkyl (meth)acrylate may be used as the above C 12-18 linear alkyl (meth)acrylate.
  • at least a portion thereof e.g., one or two types, or all, i.e., all types
  • Alkyl (meth)acrylates can be used.
  • the C 5-18 linear alkyl (meth)acrylate is an alkyl (meth)acrylate having a biomass-derived C 5-18 linear alkyl group at the ester end (hereinafter “biomass C 5-18 linear (also referred to as “chain alkyl (meth)acrylate”) is used.
  • biomass C 5-18 linear alkyl (meth)acrylate while reducing dependence on fossil resource-based materials, the effects of the technology disclosed here (lower adhesive force in low-speed peeling, high-speed peeling The effect of suppressing the increase in peeling force in ( ) is preferably realized.
  • the biomass C 5-18 linear alkyl (meth)acrylates are esters of biomass-derived alkanols with biomass-derived or non-biomass-derived (meth)acrylic acid, e.g. Esters with (meth)acrylic acid may be used. In such compounds, only the linear alkyl groups are derived from biomass.
  • the number of carbon atoms in the straight-chain alkyl group of the biomass C 5-18 straight-chain alkyl (meth)acrylate is preferably 14 or less, more preferably 12 or less, still more preferably 11 or less, and particularly preferably 10, from the viewpoint of adhesive properties. or less (eg 9 or 8 or less). Also, the number of carbon atoms is preferably 5 or more, more preferably 6 or more, and still more preferably 7 or more.
  • the biomass carbon ratio of the synthesized acrylic polymer can be increased.
  • the ratio of the biomass C5-18 straight-chain alkyl (meth)acrylate to the total C5-18 straight-chain alkyl (meth)acrylate used as the monomer component of the acrylic polymer may be, for example, 1% by weight or more. , 10% by weight or more is suitable, preferably 30% by weight or more, more preferably 50% by weight or more (for example, more than 50% by weight); % or more, 95% by weight or more, or 99% by weight or more.
  • the technology disclosed herein can be preferably implemented in a mode using an acrylic polymer having a monomer composition containing only biomass C 5-18 linear alkyl (meth)acrylate as the C 5-18 linear alkyl (meth)acrylate. . Therefore, the upper limit of the ratio of biomass C 5-18 linear alkyl (meth)acrylate to the total C 5-18 linear alkyl (meth)acrylate is 100% by weight. In some other embodiments, the proportion of biomass C 5-18 linear alkyl (meth)acrylates in total C 5-18 linear alkyl (meth)acrylates may be 95% by weight or less, and may be 70% by weight. % or less, 50 wt % or less (for example, less than 50 wt %), 30 wt % or less, 10 wt % or less, or 1 wt % or less.
  • the biomass C 5-18 linear alkyl (meth)acrylates include one or more C 5-11 linear alkyl (meth)acrylates (hereinafter “biomass C 5-11 linear alkyl (meth)acrylates meth)acrylate”) and one or more C 12-18 linear alkyl (meth)acrylates may be used in combination.
  • the C 12-18 linear alkyl (meth)acrylate may be one having a biomass-derived linear alkyl group (biomass C 12-18 linear alkyl (meth)acrylate), or a non-biomass-derived may have a straight-chain alkyl group.
  • both the C 5-11 linear alkyl (meth)acrylate and the C 12-18 linear alkyl (meth)acrylate are preferably biomass-derived materials.
  • the ratio of biomass C 5-11 linear alkyl (meth)acrylate to C 5-18 linear alkyl (meth)acrylate may be, for example, 1% by weight or more, 10% by weight or more, or 30% by weight or more. It may be at least 50% by weight, at least 70% by weight, at least 90% by weight, or at least 99% by weight.
  • the proportion of biomass C5-11 linear alkyl (meth)acrylate in C5-18 linear alkyl (meth)acrylate may be 99% by weight or less, may be 90% by weight or less, and may be 70% by weight. % or less, 50 wt% or less, 30 wt% or less, 10 wt% or less, or 1 wt% or less.
  • the C 5-18 linear alkyl (meth)acrylate is n-heptyl (meth)acrylate having a biomass-derived n-heptyl group (hereinafter also referred to as “biomass heptyl (meth)acrylate”).
  • biomass heptyl (meth)acrylate By using biomass heptyl (meth)acrylate, the effects of the technology disclosed herein can be exhibited particularly favorably while reducing dependence on fossil resource-based materials. Among them, biomass heptyl acrylate is particularly preferable from the viewpoint of adhesive properties.
  • the ratio of biomass heptyl (meth)acrylate to the total C 5-18 linear alkyl (meth)acrylate used as the monomer component of the acrylic polymer may be, for example, 1% by weight or more, and 10% by weight or more is suitable, preferably 30 wt% or more, more preferably 50 wt% or more (e.g., more than 50 wt%), may be 70 wt% or more, may be 80 wt% or more, may be 85 wt% or more, may be 90 wt% or more. It may be at least 92% by weight, or at least 95% by weight.
  • the effect of use can be effectively expressed while improving the biomass carbon ratio of the acrylic polymer.
  • the technology disclosed herein can be preferably practiced in a mode using an acrylic polymer with a monomer composition containing only biomass heptyl (meth)acrylate as the C 5-18 linear alkyl (meth)acrylate. Therefore, the upper limit of the proportion of biomass heptyl (meth)acrylate in the total C 5-18 linear alkyl (meth)acrylate is 100% by weight.
  • the proportion of biomass heptyl (meth)acrylate in total C 5-18 linear alkyl (meth)acrylates may be 95 wt% or less, may be 75 wt% or less, and may be 60 wt% or less. It may be less than or equal to 50 wt% (for example, less than 50 wt%), less than or equal to 30 wt%, less than or equal to 10 wt%, or less than or equal to 1 wt%.
  • the monomer component forming the acrylic polymer may contain other monomers (copolymerizable monomers) copolymerizable with the chain alkyl (meth)acrylate in addition to the chain alkyl (meth)acrylate. good.
  • the copolymerizable monomers may be used singly or in combination of two or more.
  • the above-mentioned copolymerizable monomer can be useful for introducing cross-linking points into the acrylic polymer and increasing the cohesive strength of the acrylic polymer.
  • the copolymerizable monomer may be biomass-derived or non-biomass-derived.
  • a carboxy group-containing monomer is used as the copolymerizable monomer.
  • a carboxy group-containing monomer as a copolymerizable monomer component for introducing a cross-linking point into an acrylic polymer in combination with a cross-linking agent (for example, an epoxy-based cross-linking agent)
  • a cross-linking agent for example, an epoxy-based cross-linking agent
  • carboxy group-containing monomers examples include ethylenically unsaturated monocarboxylic acids such as acrylic acid, methacrylic acid, and crotonic acid; ethylenically unsaturated dicarboxylic acids such as itaconic acid, maleic acid, and fumaric acid, and their anhydrides (maleic anhydride, isotanoic anhydride, etc.). Among them, acrylic acid and methacrylic acid are preferred, and acrylic acid is more preferred.
  • the carboxy group-containing monomers may be used singly or in combination of two or more.
  • the content of the carboxy group-containing monomer (preferably (meth)acrylic acid) in the monomer component forming the acrylic polymer may be, for example, 0.01% by weight or more of the total monomer component, or 0.1 weight percent or more, suitably greater than 0.5 wt. , 3% by weight or more.
  • the content of the carboxy group-containing monomer (preferably (meth)acrylic acid) in the entire monomer component is, for example, less than 15% by weight, and is suitably 10% by weight or less. In a preferred embodiment, it may be 8% by weight or less, 6% by weight or less, or 5% by weight or less.
  • the cohesive force is improved, and it is easy to adjust to a good adhesive force that can be removed, for example, it can be removed again. It is easy to form a pressure-sensitive adhesive suitable for surface protection applications.
  • the carboxy group-containing monomer preferably (meth)acrylic acid
  • the monomer component forming the acrylic polymer may contain other copolymerizable monomers.
  • Other copolymerizable monomers are defined as monomers different from the chain alkyl (meth)acrylate and the carboxy group-containing monomer.
  • Other copolymerizable monomers can be used singly or in combination of two or more.
  • Suitable copolymerizable monomers include the following. Hydroxyl group-containing monomers: for example, 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 3-hydroxypropyl (meth)acrylate, 2-hydroxybutyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate hydroxyalkyl (meth)acrylates such as; unsaturated alcohols such as vinyl alcohol and allyl alcohol; Monomers containing sulfonic or phosphoric acid groups: for example, styrenesulfonic acid, allylsulfonic acid, sodium vinylsulfonate, 2-(meth)acrylamido-2-methylpropanesulfonic acid, (meth)acrylamidopropanesulfonic acid, sulfo propyl (meth)acrylate, (meth)acryloyloxynaphthalenesulfonic acid, 2-hydroxyethyl acryloyl phosphate and the like
  • Epoxy group-containing monomers For example, epoxy group-containing acrylates such as glycidyl (meth)acrylate and 2-ethylglycidyl (meth)acrylate, allyl glycidyl ether, glycidyl ether (meth)acrylate, and the like. Cyano group-containing monomers: for example acrylonitrile, methacrylonitrile and the like. Isocyanate group-containing monomers: for example, 2-isocyanatoethyl (meth)acrylate and the like.
  • Amido group-containing monomers for example, (meth)acrylamide; N,N-dimethyl(meth)acrylamide, N,N-diethyl(meth)acrylamide, N,N-dipropyl(meth)acrylamide, N,N-diisopropyl(meth) N,N-dialkyl(meth)acrylamides such as acrylamide, N,N-di(n-butyl)(meth)acrylamide, N,N-di(t-butyl)(meth)acrylamide; N-ethyl(meth) N-alkyl (meth)acrylamides such as acrylamide, N-isopropyl (meth)acrylamide, N-butyl (meth)acrylamide, Nn-butyl (meth)acrylamide; N-vinylcarboxylic acid amides such as N-vinylacetamide ; monomers having a hydroxyl group and an amide group, such as N-hydroxyalkyl (me
  • N-vinyl-2-pyrrolidone N-methylvinylpyrrolidone, N-vinylpyridine, N-vinylpiperidone, N-vinylpyrimidine, N-vinylpiperazine, N-vinylpyrazine, N- Vinylpyrrole, N-vinylimidazole, N-vinyloxazole, N-(meth)acryloyl-2-pyrrolidone, N-(meth)acryloylpiperidine, N-(meth)acryloylpyrrolidine, N-vinylmorpholine, N-vinyl-3 -morpholinone, N-vinyl-2-caprolactam, N-vinyl-1,3-oxazin-2-one, N-vinyl-3,5-morpholinedione, N-vinylpyrazole, N-vinylisoxazole, N-vinyl thiazole, N-
  • Maleimides For example, N-cyclohexylmaleimide, N-isopropylmaleimide, N-laurylmaleimide, N-phenylmaleimide and the like.
  • Itaconimides for example, N-methylitaconimide, N-ethylitaconimide, N-butylitaconimide, N-octylitaconimide, N-2-ethylhexylitaconimide, N-cyclohexylitaconimide, N-lauryl itaconimide and the like.
  • Aminoalkyl (meth)acrylates for example, aminoethyl (meth)acrylate, N,N-dimethylaminoethyl (meth)acrylate, N,N-diethylaminoethyl (meth)acrylate, t (meth)acrylate - butylaminoethyl.
  • Alkoxy group-containing monomers for example, 2-methoxyethyl (meth)acrylate, 3-methoxypropyl (meth)acrylate, 2-ethoxyethyl (meth)acrylate, propoxyethyl (meth)acrylate, (meth)acrylic acid
  • Alkoxyalkyl (meth)acrylates such as butoxyethyl and ethoxypropyl (meth)acrylate
  • Alkoxyalkylene glycol (meth)acrylates such as methoxyethylene glycol (meth)acrylate and methoxypolypropylene glycol (meth)acrylate.
  • Vinyl esters For example, vinyl acetate, vinyl propionate and the like.
  • Vinyl ethers For example, vinyl alkyl ethers such as methyl vinyl ether and ethyl vinyl ether.
  • Aromatic vinyl compounds for example, styrene, ⁇ -methylstyrene, vinyltoluene and the like.
  • Olefins For example, ethylene, butadiene, isoprene, isobutylene and the like.
  • (Meth)acrylates having an alicyclic hydrocarbon group for example, cyclopentyl (meth)acrylate, cyclohexyl (meth)acrylate, isobornyl (meth)acrylate, dicyclopentanyl (meth)acrylate and the like.
  • (Meth)acrylates having an aromatic hydrocarbon group for example, phenyl (meth)acrylate, phenoxyethyl (meth)acrylate, benzyl (meth)acrylate and the like.
  • heterocycle-containing (meth)acrylates such as tetrahydrofurfuryl (meth)acrylate, halogen atom-containing (meth)acrylates such as vinyl chloride and fluorine atom-containing (meth)acrylates, silicon atom-containing such as silicone (meth)acrylates (meth)acrylates, (meth)acrylates obtained from terpene compound derivative alcohols, and the like.
  • the monomer component that constitutes the acrylic polymer may or may not contain the other copolymerizable monomers.
  • the amount of the other copolymerizable monomer is not particularly limited, and may be appropriately selected according to the purpose and application.
  • the content of other copolymerizable monomers in the monomer component is, for example, less than 50% by weight (for example, less than 30% by weight), preferably less than 10% by weight, and less than 5% by weight. More preferably, it may be less than 3% by weight (for example, less than 1% by weight).
  • the technology disclosed herein can be preferably practiced in a mode in which the monomer component does not substantially contain other copolymerizable monomers.
  • biomass carbon ratio of the monomer component constituting the acrylic polymer may be, for example, 1% or more, suitably 10% or more, preferably 30% or more, more preferably 30% or more. is 50% or more (eg, more than 50%), may be 60% or more, may be 65% or more, may be 70% or more, may be 80% or more, or may be 90% to 100%.
  • the method for obtaining the acrylic polymer is not particularly limited, and various polymerization methods known as synthesis methods for acrylic polymers, such as solution polymerization, emulsion polymerization, bulk polymerization, suspension polymerization, and photopolymerization. can be adopted as appropriate.
  • a solution polymerization method can be preferably employed.
  • An embodiment employing a solution polymerization method can be advantageous from the viewpoint of transparency, adhesion performance, and the like.
  • a method for supplying the monomers when carrying out solution polymerization a batch charging method for supplying all monomer raw materials at once, a continuous supply (dropping) method, a divided supply (dropping) method, or the like can be appropriately employed.
  • the polymerization temperature at the time of solution polymerization can be appropriately selected according to the type of monomer and solvent used, the type of polymerization initiator, etc. ° C.).
  • the solvent (polymerization solvent) used for solution polymerization can be appropriately selected from conventionally known organic solvents (toluene, ethyl acetate, etc.).
  • the initiator used for polymerization may be a conventionally known polymerization initiator (for example, an azo polymerization initiator such as 2,2'-azobisisobutyronitrile (AIBN) or a peroxide polymerization initiator). initiator, etc.).
  • the amount of the polymerization initiator used may be a normal amount, for example, about 0.005 to 1 part by weight (typically about 0.01 to 1 part by weight) per 100 parts by weight of the monomer component. ).
  • the weight-average molecular weight (Mw) of the acrylic polymer is usually about 10 ⁇ 10 4 or more.
  • An acrylic polymer having such an Mw tends to yield a pressure-sensitive adhesive exhibiting good cohesiveness.
  • the Mw of the acrylic polymer is, for example, 30 ⁇ 10 4 or more, preferably 50 ⁇ 10 4 or more, from the viewpoint of removable adhesive strength, cohesive strength, and the like. , 70 ⁇ 10 4 or more, more than 100 ⁇ 10 4 , 110 ⁇ 10 4 or more, 120 ⁇ 10 4 or more, or 130 ⁇ 10 4 or more.
  • the Mw of the acrylic polymer By setting the Mw of the acrylic polymer to a predetermined value or more, the cohesive force of the pressure-sensitive adhesive is improved, and it is easy to prevent the occurrence of adhesive residue on the surface of the adherend. Moreover, from the viewpoint of adhesion to the adherend, the Mw of the acrylic polymer is usually approximately 500 ⁇ 10 4 or less, may be 300 ⁇ 10 4 or less, or may be 100 ⁇ 10 4 . or less (for example, less than 100 ⁇ 10 4 ). By setting the Mw to a predetermined value or less, the pressure-sensitive adhesive tends to have appropriate fluidity and wettability (adhesion) to the adherend is likely to be obtained.
  • the surface protection film does not peel off from the adherend during use, and can preferably fulfill its protective function. It is particularly significant that the Mw of the acrylic polymer obtained by the solution polymerization method is within the preferred range described above.
  • the Mw of the acrylic polymer can be measured by gel permeation chromatography (GPC) and calculated as a value converted to standard polystyrene. Specifically, it can be obtained by measuring under the following conditions using a GPC measurement device with the trade name "HLC-8220GPC" (manufactured by Tosoh Corporation). The same applies to the examples described later.
  • GPC gel permeation chromatography
  • crosslinking agent The adhesive compositions disclosed herein contain a cross-linking agent.
  • a cross-linking agent can serve to increase the cohesive strength of the adhesive.
  • the cross-linking agent can be selected from various cross-linking agents known in the field of adhesives. Examples of such cross-linking agents include epoxy-based cross-linking agents, isocyanate-based cross-linking agents, oxazoline-based cross-linking agents, aziridine-based cross-linking agents, melamine-based cross-linking agents, peroxide-based cross-linking agents, urea-based cross-linking agents, and metal alkoxide-based cross-linking agents.
  • a crosslinking agent can be used individually by 1 type or in combination of 2 or more types.
  • the cross-linking agent may be biomass-derived or non-biomass-derived.
  • a cross-linking agent derived from biomass is preferably used from the viewpoint of production of an acrylic pressure-sensitive adhesive that takes into consideration the suppression of dependence on fossil resource-based materials.
  • the technology disclosed herein can be preferably implemented in a mode in which both the acrylic polymer and the cross-linking agent contained in the pressure-sensitive adhesive composition are derived from biomass.
  • the amount of cross-linking agent used is not particularly limited.
  • the amount of the cross-linking agent used can be selected, for example, from the range of 0.1 to 20 parts by weight with respect to 100 parts by weight of the acrylic polymer. From the viewpoint of achieving both improved cohesive strength and adhesion to the adherend in a well-balanced manner, the amount of the cross-linking agent used relative to 100 parts by weight of the acrylic polymer is usually preferably 15 parts by weight or less, preferably 10 parts by weight. 8 parts by weight or less, 7 parts by weight or less, 0.5 parts by weight or more is suitable, and 1 part by weight or more is also acceptable.
  • By adjusting the amount of the cross-linking agent to be used in an appropriate range it is possible to increase the cohesive force of the pressure-sensitive adhesive, prevent the occurrence of adhesive residue on the adherend, and obtain adhesion to the adherend. .
  • the cross-linking agent preferably contains at least an epoxy-based cross-linking agent.
  • Epoxy-based cross-linking agents may be used singly or in combination of two or more.
  • the epoxy-based cross-linking agent may be biomass-derived or non-biomass-derived.
  • a biomass-derived epoxy-based cross-linking agent is preferably used from the viewpoint of production of an acrylic pressure-sensitive adhesive that takes into consideration the suppression of dependence on fossil resource-based materials.
  • the epoxy-based cross-linking agent may be used in combination with another cross-linking agent such as an isocyanate-based cross-linking agent.
  • epoxy-based cross-linking agent a compound having two or more epoxy groups in one molecule can be used without particular limitation.
  • An epoxy-based cross-linking agent having 3 to 5 epoxy groups in one molecule is preferred.
  • Epoxy-based cross-linking agents may be used singly or in combination of two or more.
  • Specific examples of epoxy-based cross-linking agents include N,N,N',N'-tetraglycidyl-m-xylenediamine, 1,3-bis(N,N-diglycidylaminomethyl)cyclohexane, and 1,6-hexane.
  • epoxy-based cross-linking agents include Mitsubishi Gas Chemical Company's trade name “TETRAD-C” and trade name “TETRAD-X”, DIC's trade name “Epiclon CR-5L”, and Nagase ChemteX Corporation. and "TEPIC-G” manufactured by Nissan Chemical Industries, Ltd. under the trade name of "Denacol EX-512".
  • the amount of the epoxy-based cross-linking agent used may be, for example, approximately 0.1 parts by weight or more, 0.5 parts by weight or more, or 1.0 parts by weight or more, relative to 100 parts by weight of the acrylic polymer. It may be greater than 1.5 parts by weight. From the viewpoint of obtaining a higher use effect, the amount of the epoxy-based cross-linking agent used relative to 100 parts by weight of the acrylic polymer may be, for example, more than 2.0 parts by weight, may be 2.5 parts by weight or more, or may be 3.0 parts by weight. parts or more, or 3.5 parts by weight or more.
  • the amount of the epoxy-based cross-linking agent to be used relative to 100 parts by weight of the acrylic polymer is usually appropriately 20 parts by weight or less, and may be 10 parts by weight or less, 8 parts by weight or less, or 6 parts by weight or less. 5 parts by weight or less (for example, less than 5 parts by weight) may be used.
  • the amount of the epoxy-based cross-linking agent By adjusting the amount of the epoxy-based cross-linking agent to an appropriate range, it is possible to increase the cohesive strength of the pressure-sensitive adhesive, easily adjust the re-peelable adhesive strength, and suppress the increase in adhesive strength over time. In addition, it is possible to prevent the occurrence of adhesive residue on the adherend and to obtain good adhesion to the adherend. Also, by limiting the amount of the epoxy-based cross-linking agent used, it is easy to form a transparent pressure-sensitive adhesive.
  • the amount of the epoxy-based cross-linking agent used may be more than 4 parts by weight with respect to 100 parts by weight of the acrylic polymer, and may be 4.5 parts by weight. It may be greater than or equal to 5 parts by weight, or greater than 5.5 parts by weight.
  • the amount of the carboxy group-containing monomer used (the total amount when two or more carboxy group-containing monomers are used) epoxy system relative to WA
  • the ratio (WB/WA) (weight basis) of the amount WB of the cross-linking agent used is not particularly limited, but from the viewpoint of increasing the cohesive strength of the adhesive, it is preferably 0.7 or more, more preferably 0.8. or more, more preferably 0.9 or more (for example, 1.0 or more), and particularly preferably 1.1 or more.
  • the ratio (WB/WA) is usually 3.0 or less, 2.0 or less, 1.8 or less, 1.6 or less, 1.4 or less, or 1.3. It can be below.
  • the isocyanate-based cross-linking agent a polyisocyanate-based cross-linking agent having two or more isocyanate groups per molecule is preferably used.
  • the number of isocyanate groups per molecule of the polyisocyanate-based cross-linking agent is preferably 2-10, for example 2-4, typically 2 or 3.
  • the polyisocyanate-based crosslinking agent include aromatic polyisocyanates such as tolylene diisocyanate and xylene diisocyanate; alicyclic isocyanates such as isophorone diisocyanate; and aliphatic polyisocyanates such as hexamethylene diisocyanate.
  • lower aliphatic polyisocyanates such as butylene diisocyanate, pentamethylene diisocyanate and hexamethylene diisocyanate
  • alicyclic polyisocyanates such as cyclopentylene diisocyanate, cyclohexylene diisocyanate and isophorone diisocyanate
  • Aromatic diisocyanates such as 4-tolylene diisocyanate, 4,4'-diphenylmethane diisocyanate, xylylene diisocyanate, and polymethylene polyphenyl diisocyanate
  • L trimethylolpropane/hexamethylene diisocyanate trimer adduct
  • isocyanurate form of hexamethylene diisocyanate manufactured by Tosoh, trade name "Coronate HX”
  • aliphatic diisocyanates such as pentamethylene diisocyanate and hexamethylene diisocyanate, isocyanurates of such aliphatic diisocyanates, and the like.
  • the adhesive composition disclosed here may contain a catalyst.
  • a catalyst By using a catalyst, the curing reaction of the pressure-sensitive adhesive composition (typically, the cross-linking reaction of the above-mentioned cross-linking agent) can proceed efficiently, and stable adhesion can be achieved from an early stage after the pressure-sensitive adhesive sheet is produced. It's easy to do.
  • the catalyst is also called a cross-linking catalyst. Examples of catalysts include tin (Sn)-containing compounds (tin-based catalysts), zirconium (Zr)-containing compounds (zirconium-based catalysts), titanium (Ti)-containing compounds (titanium-based catalysts), iron (Fe)-containing compounds (iron-based catalysts).
  • a catalyst can be used individually by 1 type or in combination of 2 or more types. The technology disclosed herein can be suitably practiced even in a mode that does not contain a catalyst.
  • additives can be blended into the adhesive composition as needed.
  • additives include surface lubricants, leveling agents, tackifying resins, plasticizers, softeners, fillers, colorants (pigments, dyes, etc.), antistatic agents, antioxidants, preservatives, light stabilizers. agents, ultraviolet absorbers, polymerization inhibitors, silane coupling agents, and the like.
  • the content of these optional additives can be appropriately set according to the purpose of use.
  • the amount of the optional additive used is, for example, less than 10 parts by weight, and is suitably about 3 parts by weight or less (for example, about 1 part by weight or less) with respect to 100 parts by weight of the acrylic polymer.
  • the form of the pressure-sensitive adhesive composition disclosed herein is not particularly limited, and water-based pressure-sensitive adhesive compositions, solvent-based pressure-sensitive adhesive compositions, and the like are preferable.
  • the water-based pressure-sensitive adhesive composition refers to a pressure-sensitive adhesive composition in the form of containing a pressure-sensitive adhesive (pressure-sensitive adhesive layer-forming component) in a water-based solvent (water-based solvent). It is a concept that includes a water-dispersed pressure-sensitive adhesive composition in which the pressure-sensitive adhesive is dispersed in water and a water-soluble pressure-sensitive adhesive composition in which the pressure-sensitive adhesive is dissolved in water.
  • the solvent-type adhesive composition refers to an adhesive composition in the form of containing an adhesive in an organic solvent.
  • the organic solvent contained in the solvent-based pressure-sensitive adhesive composition one or more organic solvents (toluene, ethyl acetate, etc.) that can be used in the above solution polymerization can be used without particular limitation.
  • the technology disclosed herein can be preferably practiced in a mode comprising a pressure-sensitive adhesive layer formed from a solvent-based pressure-sensitive adhesive composition.
  • the effects of the technique disclosed herein are preferably realized.
  • the adhesive composition disclosed herein preferably has a gel fraction of 70% or more after drying.
  • a pressure-sensitive adhesive having a gel fraction of 70% or more is less likely to cause deformation or damage such as dents due to external force during production, and less likely to cause changes in appearance.
  • Such a pressure-sensitive adhesive tends to form a pressure-sensitive adhesive sheet having a smooth surface. For example, when a transparent pressure-sensitive adhesive sheet is formed and an adherend is inspected through the pressure-sensitive adhesive sheet, highly accurate inspection is possible, which is preferable.
  • the gel fraction is more preferably over 80%, and may be over 85% (for example, 90% or more).
  • the gel fraction may be 100%, but may be, for example, less than 99% or less than 95% (for example, 94% or less) from the viewpoint of adhesion to the adherend.
  • the drying conditions for the pressure-sensitive adhesive composition for measuring the gel fraction are 130° C. for 3 minutes. Specifically, the gel fraction is measured by the method described in Examples below. Since the gel fraction after drying of the adhesive composition can be the gel fraction of the adhesive (layer), the gel fraction of the adhesive (layer) constituting the adhesive sheet described later is also set from the above range. can be
  • the pressure-sensitive adhesive composition contains a biomass-derived material, and the biomass-carbon ratio of the non-volatile matter (also the biomass-carbon ratio of the pressure-sensitive adhesive) can be a predetermined value or higher.
  • the non-volatile biomass carbon ratio of the pressure-sensitive adhesive composition is, for example, 1% or more, may be 10% or more, preferably 30% or more, and more preferably 50% or more.
  • a high biomass carbon ratio of the pressure-sensitive adhesive means that the amount of fossil resource-based materials such as petroleum used is small. From this point of view, the higher the biomass carbon ratio of the adhesive, the better.
  • the non-volatile biomass carbon ratio of the adhesive composition may be 55% or more, 60% or more, 65% or more, 70% or more, 75% or more, It may be 80% or more, or may be more than 80%.
  • the upper limit of the biomass carbon ratio is 100% by definition, and may be 99% or less. From the viewpoint of availability of materials, it may be 95% or less or 90% or less. From the viewpoint of facilitating good adhesion performance, in some embodiments, the non-volatile biomass carbon ratio of the pressure-sensitive adhesive composition may be, for example, 90% or less, 85% or less, or 80% or less. good.
  • the pressure-sensitive adhesive sheet comprising a pressure-sensitive adhesive layer formed from any of the pressure-sensitive adhesive compositions disclosed herein.
  • the pressure-sensitive adhesive sheet may be a pressure-sensitive adhesive sheet with a substrate having the pressure-sensitive adhesive layer on one or both sides of a non-releasable substrate (supporting substrate), and the pressure-sensitive adhesive layer is held by a release liner. It may be a substrate-less pressure-sensitive adhesive sheet (that is, a pressure-sensitive adhesive sheet having no non-releasable substrate).
  • the pressure-sensitive adhesive sheet disclosed herein has easy release properties in low-speed release and suppresses an increase in release force in high-speed release, so that it can be easily peeled regardless of the peel speed. In addition, there is a tendency that an increase in adhesive strength over time is suppressed. Therefore, it is suitable as a surface protection film that can be peeled again after use.
  • the structure of an adhesive sheet according to one embodiment is schematically shown in FIG.
  • the pressure-sensitive adhesive sheet 1 includes a sheet-like support base material (for example, a resin film) 10 having a first surface 10A and a second surface 10B, and a base material provided with an adhesive layer 21 provided on the first surface 10A side. It is configured as a single-sided adhesive sheet with The pressure-sensitive adhesive layer 21 is fixedly provided on the first surface 10A side of the supporting substrate 10 , that is, without the intention of separating the pressure-sensitive adhesive layer 21 from the supporting substrate 10 .
  • a sheet-like support base material for example, a resin film
  • the pressure-sensitive adhesive layer 21 is fixedly provided on the first surface 10A side of the supporting substrate 10 , that is, without the intention of separating the pressure-sensitive adhesive layer 21 from the supporting substrate 10 .
  • Such a single-sided adhesive pressure-sensitive adhesive sheet 1 is suitable as a surface protection film that is used by attaching the pressure-sensitive adhesive surface to the surface of an adherend (object to be protected, for example, an optical component such as a polarizing plate).
  • an optical component such as a polarizing plate.
  • the surface (adhesive surface) 21A of the pressure-sensitive adhesive layer 21 is protected by a release liner 31 having a release surface on at least the side facing the pressure-sensitive adhesive layer 21. It can be a component of the pressure-sensitive adhesive sheet 100 with a release liner.
  • the adhesive sheet 1 is wound so that the adhesive surface 21A becomes the second surface (back surface) of the supporting substrate 10.
  • 10B may be in a protected form (roll form).
  • Examples of the release liner include a release liner having a release layer on the surface of a liner substrate such as a resin film or paper, and a low-grade resin such as a polyolefin resin (e.g., polyethylene, polypropylene) or a fluororesin.
  • a release liner or the like made of an adhesive material can be used.
  • the release layer may be formed by surface-treating the liner base material with a release treatment agent such as a silicone-based, long-chain alkyl-based, fluorine-based, or molybdenum sulfide-based release agent.
  • a material formed using a biomass-derived material or a recycled material (recycled film, etc.) can be preferably used, similarly to the base material of the pressure-sensitive adhesive sheet described later.
  • the concept of the adhesive sheet referred to here may include items called adhesive tapes, adhesive labels, adhesive films, and the like.
  • the pressure-sensitive adhesive sheet may be in the form of a roll or sheet. Also, the pressure-sensitive adhesive sheet may be processed into various shapes.
  • the formation of the adhesive (layer) from the adhesive composition can be performed by a conventionally known method.
  • a PSA layer A pressure-sensitive adhesive sheet can be formed by forming a layer consisting of a pressure-sensitive adhesive.
  • a method (direct method) of forming a pressure-sensitive adhesive layer by directly applying (typically applying) a pressure-sensitive adhesive composition to the substrate and curing the composition is preferably adopted. can do.
  • a method of applying a pressure-sensitive adhesive composition to a surface having releasability (release surface) and curing the composition to form a pressure-sensitive adhesive layer on the surface and transferring the pressure-sensitive adhesive layer to a substrate may be adopted.
  • the release surface the surface of a release liner, the back surface of a base material subjected to a release treatment, or the like can be used.
  • curing of the pressure-sensitive adhesive composition can be performed by subjecting the pressure-sensitive adhesive composition to a curing treatment such as drying, crosslinking, polymerization, or cooling. Two or more curing treatments may be performed simultaneously or stepwise.
  • the pressure-sensitive adhesive composition is carried out using known or commonly used coaters such as gravure roll coaters, reverse roll coaters, kiss roll coaters, dip roll coaters, die coaters, bar coaters, knife coaters, and spray coaters. can be done.
  • the adhesive composition may be applied by impregnation, curtain coating, or the like.
  • the drying temperature can be, for example, about 40 to 150°C, preferably about 60 to 130°C.
  • aging may be performed for the purpose of adjusting component migration in the pressure-sensitive adhesive layer, progressing the cross-linking reaction, relaxing distortion that may exist in the substrate or the pressure-sensitive adhesive layer, and the like. good.
  • the thickness of the adhesive layer is, for example, approximately 1 ⁇ m or more, preferably approximately 3 ⁇ m or more (for example, approximately 5 ⁇ m or more). From the viewpoint of adhesion to adherends, etc., the thickness is preferably about 10 ⁇ m or more, more preferably about 14 ⁇ m or more, and even more preferably about 17 ⁇ m or more.
  • the thickness can be, for example, approximately 100 ⁇ m or less, suitably approximately 50 ⁇ m or less (for example, approximately 30 ⁇ m or less), and preferably approximately 25 ⁇ m or less.
  • a pressure-sensitive adhesive layer having the thickness described above is suitable as a pressure-sensitive adhesive layer for use as a surface protection film.
  • the material of the supporting substrate used as the support of the pressure-sensitive adhesive sheet disclosed herein is not particularly limited, and for example, a resin film can be preferably employed.
  • the resin film may be formed by molding various resin materials into a film shape.
  • the resin material those capable of forming a resin film excellent in one or more of properties such as transparency, mechanical strength, thermal stability, moisture shielding property, and isotropy are preferred.
  • polyesters such as polyethylene terephthalate (PET), polyethylene naphthalate (PEN), and polybutylene terephthalate; celluloses such as diacetyl cellulose and triacetyl cellulose; polycarbonates; acrylic polymers such as polymethyl methacrylate;
  • a resin film composed of a resin material as a component can be preferably used as the substrate.
  • resin material constituting the resin film examples include styrene-based polymers such as polystyrene and acrylonitrile-styrene copolymers; polyolefins such as polyethylene, polypropylene, polyolefins having a cyclic or norbornene structure, and ethylene-propylene.
  • styrene-based polymers such as polystyrene and acrylonitrile-styrene copolymers
  • polyolefins such as polyethylene, polypropylene, polyolefins having a cyclic or norbornene structure, and ethylene-propylene.
  • Polyvinyl chlorides Polyamides such as nylon 6, nylon 6,6 and aromatic polyamides; Alternatively, polyimides, polysulfones, polyethersulfones, polyetheretherketones, polyphenylene sulfides, fluorine-based resins, polyvinyl alcohols, polyvinyl acetates, polyvinylidene chlorides, polyvinyl butyrals, polyarylates, poly
  • a resin film composed of a resin material containing oxymethylenes, epoxy resins, or the like as a main component may be used as the substrate.
  • the resin material constituting the resin film may be a blend of two or more of these.
  • the term "resin film” means a non-porous structure and typically substantially voidless resin film. Therefore, the resin film is a concept distinguished from foam films, nonwoven fabrics, and woven fabrics.
  • base materials include foam sheets made of polyurethane foam, polyethylene foam, polychloroprene foam, etc., and various fibrous substances (natural fibers such as hemp and cotton, synthetic fibers such as polyester and vinylon). , Semi-synthetic fibers such as acetate, etc.) Woven and non-woven fabrics made by spinning alone or blended; etc.
  • a base material having a structure in which these are combined may be used.
  • Examples of such a substrate having a composite structure include a substrate having a structure in which a metal foil and the plastic film are laminated, and a plastic sheet reinforced with inorganic fibers such as glass cloth.
  • the base material may be formed from a biomass-derived material or may be formed from a non-biomass-derived material.
  • a biomass-derived base material (typically a resin film) is preferably used from the viewpoint of pressure-sensitive adhesive sheet production that takes into account the suppression of dependence on fossil resource-based materials.
  • the base material may be formed using recyclable materials or recycled materials (also referred to as recycled materials).
  • a resin film is preferably used as such a recycled material. Since resin films (e.g., polyester films such as PET films) can be recycled, sustainable reproduction can be achieved by reusing used resin films regardless of whether plant-derived materials are used or not. is possible, and the environmental load can be reduced. Such recyclable resin films and recycled resin films are also called recycled films.
  • the recycled material (for example, recycled film) may be formed from a biomass-derived material, or may be formed from a non-biomass-derived material.
  • a resin film in which a resin (polyester resin) containing polyester as a main component (a component containing more than 50% by weight) is molded into a film shape is used as the base material.
  • a resin film (PET film) in which the polyester is mainly PET, a resin film (PEN film) in which the polyester is mainly PEN, or the like can be preferably employed.
  • the base material may have a single-layer structure or a multilayer structure. Therefore, a resin film that can be used as a substrate may also have a single-layer structure or a multi-layer structure of two or more layers (for example, a three-layer structure). A resin film having a single-layer structure can be preferably used as the substrate.
  • additives such as antioxidants, ultraviolet absorbers, antistatic components, plasticizers, colorants (pigments, dyes, etc.) are blended with the base material (typically a resin film) as necessary.
  • the base material typically a resin film
  • the adhesive layer side surface of the base material may be subjected to surface treatment such as chromic acid treatment, ozone exposure, flame exposure, high voltage shock exposure, and ionizing radiation treatment.
  • a surface treatment may be, for example, a treatment for enhancing adhesion between the substrate and the pressure-sensitive adhesive layer.
  • the surface of the substrate on the pressure-sensitive adhesive layer side may be subjected to a primer treatment. Silicone primer treatment is preferred from the viewpoint of adhesion to the silicone-based pressure-sensitive adhesive.
  • the backside of the substrate can be hardcoated. As a result, the scratch resistance of the back surface of the base material is improved, and when the adhesive sheet is used as a protective sheet, more excellent protective performance can be exhibited.
  • the base material may be subjected to antistatic treatment from the viewpoint of suppressing the generation of static electricity.
  • the substrate may also be subjected to various treatments such as antifouling, anti-fingerprint, anti-glare, and anti-reflection treatments.
  • the thickness of the base material can be appropriately selected in consideration of the application, purpose, usage pattern, etc. of the adhesive sheet.
  • a base material having a thickness of about 10 ⁇ m or more is suitable from the standpoint of workability such as strength and handleability, and the thickness is preferably about 20 ⁇ m or more, more preferably about 30 ⁇ m or more (for example, 35 ⁇ m or more).
  • the thickness of the substrate is suitably about 200 ⁇ m or less, preferably about 150 ⁇ m or less, more preferably about 100 ⁇ m or less, even more preferably about 75 ⁇ m or less (for example, 50 ⁇ m or less) from the viewpoint of cost.
  • a substrate having the thickness described above is suitable, for example, as a substrate for a surface protective film.
  • the pressure-sensitive adhesive sheet (preferably surface protective film) that has been sufficiently aged has an initial low-speed adhesive strength (F0 Low ) measured at a tensile speed of 300 mm/min of 3.0 N/25 mm or less.
  • F0 Low initial low-speed adhesive strength measured at a tensile speed of 300 mm/min of 3.0 N/25 mm or less.
  • the aging of the pressure-sensitive adhesive sheet can be performed, for example, by storing the pressure-sensitive adhesive sheet in an environment of 50° C. for 3 days.
  • a pressure-sensitive adhesive sheet (preferably a surface protection film) that satisfies this property has a suppressed increase in adhesive strength over time, and a low peel strength when peeled from an adherend (for example, an object to be protected). Therefore, it is easy to peel off.
  • the initial low-speed adhesive strength (F0 Low ) is more preferably 1.0 N/25 mm or less (e.g., 0.2 N/25 mm or less), still more preferably 0.14 N/25 mm or less (e.g., less than 0.14 N/25 mm), particularly preferably 0.12 N/25 mm or less (for example, 0.1 N/25 mm or less).
  • the initial low-speed adhesive strength (F0 Low ) is suitably 0.01 N/25 mm or more, and may be 0.03 N/25 mm or more. , 0.05 N/25 mm or more.
  • the initial low-speed adhesive strength (F0 Low ) is measured by the method described in Examples below.
  • the fully aged pressure-sensitive adhesive sheet (preferably surface protective film) has an initial high-speed adhesive strength (F0 High ) measured at a tensile speed of 30 m/min of 5.0 N/25 mm or less.
  • F0 High initial high-speed adhesive strength
  • the aging of the pressure-sensitive adhesive sheet can be performed, for example, by storing the pressure-sensitive adhesive sheet in an environment of 50° C. for 3 days.
  • a pressure-sensitive adhesive sheet that satisfies these properties has a suppressed peel force when peeled from an adherend at a relatively high speed, and therefore tends to exhibit excellent peelability regardless of the peel speed.
  • the initial high-speed adhesive strength (F0 High ) is more preferably 3.0 N/25 mm or less (for example, 2.0 N/25 mm or less), still more preferably 1.5 N/25 mm or less, especially It is preferably 1.2 N/25 mm or less (for example, 1.0 N/25 mm or less).
  • the initial high-speed adhesive strength (F0 High ) is suitably 0.1 N/25 mm or more, and may be 0.3 N/25 mm or more. , 0.5 N/25 mm or more.
  • the initial high-speed adhesive strength (F0 High ) is specifically measured by the method described in Examples below.
  • the fully aged pressure-sensitive adhesive sheet (preferably surface protective film) is attached to the adherend, stored at 50 ° C. for 7 days, and then measured at a tensile speed of 300 mm / min.
  • the low-speed adhesive strength (F1 Low ) over time is preferably 3.0 N/25 mm or less.
  • the aging of the pressure-sensitive adhesive sheet can be performed, for example, by storing the pressure-sensitive adhesive sheet in an environment of 50° C. for 3 days.
  • a pressure-sensitive adhesive sheet (preferably a surface protection film) that satisfies this property has a suppressed increase in adhesive strength over time, and a low peel strength when peeled from an adherend (for example, an object to be protected). Therefore, it is easy to peel off.
  • the low-speed adhesive strength over time (F1 Low ) is more preferably 1.0 N/25 mm or less (e.g., 0.2 N/25 mm or less), and still more preferably 0.14 N/25 mm or less (e.g., less than 0.14 N/25 mm), particularly preferably 0.12 N/25 mm or less (for example, 0.1 N/25 mm or less).
  • the low-speed adhesion over time (F1 Low ) is suitably 0.01 N/25 mm or more, and may be 0.03 N/25 mm or more. , 0.05 N/25 mm or more.
  • the low-speed adhesion over time (F1 Low ) is specifically measured by the method described in Examples below.
  • the fully aged pressure-sensitive adhesive sheet (preferably surface protective film) is attached to the adherend, stored at 50° C. for 7 days, and then measured at a tensile speed of 30 m / min.
  • the high-speed adhesive strength (F1 High ) over time is preferably 5.0 N/25 mm or less.
  • the aging of the pressure-sensitive adhesive sheet can be performed, for example, by storing the pressure-sensitive adhesive sheet in an environment of 50° C. for 3 days. A pressure-sensitive adhesive sheet that satisfies these properties has a suppressed peel force when peeled from an adherend at a relatively high speed, and therefore tends to exhibit excellent peelability regardless of the peel speed.
  • the high-speed adhesive force F1 High over time is more preferably 3.0 N/25 mm or less (for example, 2.0 N/25 mm or less), still more preferably 1.5 N/25 mm or less, and particularly preferably It is 1.2 N/25 mm or less (for example, 1.0 N/25 mm or less).
  • the high-speed adhesion over time (F1 High ) is suitably 0.1 N/25 mm or more, and may be 0.3 N/25 mm or more. , 0.5 N/25 mm or more.
  • the time-dependent high-speed adhesive strength (F1 High ) is measured by the method described in Examples below.
  • the adhesive sheet preferably has transparency with a total light transmittance of about 50% or more. More preferably, the transparent pressure-sensitive adhesive sheet has a total light transmittance of 80% or more (for example, 85% or more). The upper limit of the total light transmittance may be about 99% or less (for example, 95% or less) in applications where transparency is required.
  • a transparent pressure-sensitive adhesive sheet is preferable because it enables highly accurate inspection, for example, when an adherend is inspected through the pressure-sensitive adhesive sheet.
  • Such an adhesive sheet is suitable as a surface protective film.
  • As the value of the total light transmittance a value measured according to JIS K 7361-1 can be adopted.
  • a pressure-sensitive adhesive sheet having a pressure-sensitive adhesive layer formed from the pressure-sensitive adhesive composition disclosed herein can be used for various purposes.
  • the pressure-sensitive adhesive disclosed herein is easy to peel regardless of the peeling speed, and is excellent in peeling workability at the time of re-peeling.
  • It is usually suitable as a surface protective film that is peeled off (removed) from an object to be protected.
  • the object to be protected by the surface protective film is not particularly limited, and it can be used as a protective film for various products, parts, and the like.
  • the surface protective film is particularly suitable as a surface protective film for protecting the surface of optical parts (for example, optical parts used as liquid crystal display panel components such as polarizing plates and wavelength plates) during processing and transportation.
  • the surface protective film protects the optical member during the production, transportation, etc. of the optical member used as a component of liquid crystal display panels, plasma display panels (PDP), organic electroluminescence (EL) displays, and the like. Suitable for protective applications.
  • surfaces applied to optical components such as polarizing plates (polarizing films, e.g., reflective polarizing films) for liquid crystal display panels, wavelength plates, retardation plates, optical compensation films, brightness enhancement films, light diffusion sheets, reflection sheets, etc. Useful as a protective film.
  • the pressure-sensitive adhesive composition disclosed herein in some embodiments, can contain an acrylic polymer with a high biomass carbon ratio, so that a conventional general acrylic pressure-sensitive adhesive (i.e., a low biomass carbon ratio
  • a conventional general acrylic pressure-sensitive adhesive i.e., a low biomass carbon ratio
  • the pressure-sensitive adhesive sheet disclosed herein can typically be preferably used as a pressure-sensitive adhesive sheet (for example, a surface protective film) with reduced dependence on fossil resource-based materials.
  • the weight average molecular weight (Mw) of the obtained acrylic polymer (A1) was 770,000.
  • the above HpA is a compound having a biomass-derived heptyl group at the ester end, synthesized using biomass-derived heptyl alcohol.
  • Example 2 A pressure-sensitive adhesive composition was prepared in the same manner as in Example 1 except that the acrylic polymer used was changed to the acrylic polymer (A2) obtained in Preparation Example A2.
  • a pressure-sensitive adhesive sheet according to this example was obtained in the same manner as in Example 1.
  • Example 1 A pressure-sensitive adhesive composition was prepared in the same manner as in Example 1 except that the acrylic polymer used was changed to the acrylic polymer (A3) obtained in Preparation Example A3, and this pressure-sensitive adhesive composition was used. A pressure-sensitive adhesive sheet according to this example was obtained in the same manner as in Example 1.
  • Example 2 A pressure-sensitive adhesive composition was prepared in the same manner as in Example 1 except that the acrylic polymer used was changed to the acrylic polymer (A4) obtained in Preparation Example A4, and this pressure-sensitive adhesive composition was used. A pressure-sensitive adhesive sheet according to this example was obtained in the same manner as in Example 1.
  • Adhesive force to glass over time F1 Prepare multiple adhesive sheets, cut them into 25 mm width and 80 mm length sizes, rub them 10 times with a clean cloth impregnated with ethanol, and wash them with a clean soda glass plate. to obtain a sample for adhesive strength evaluation.
  • the evaluation sample was left in an environment of 50° C. for 7 days. After 7 days, the sample was taken out and allowed to stand at room temperature (23° C.) for 1 hour.
  • Adhesion [N/25 mm] was measured under each condition of 30 m/min.
  • a soda glass plate product number “S200423” manufactured by Matsunami Glass Co., Ltd. or an equivalent thereof is used.
  • As the high-speed peeling tester a trade name "VPA-H200” manufactured by Kyowa Interface Science Co., Ltd. or its equivalent is used.
  • Table 1 shows an overview and evaluation results of each example.
  • the above HpA is a compound having a biomass-derived heptyl group at the ester end, synthesized using biomass-derived heptyl alcohol.
  • Example 6 The solution of the acrylic polymer (A5) obtained in Preparation Example A5 was diluted with ethyl acetate to a solid content concentration of 22%, and the solution was added with an epoxy cross-linking agent (B1) per 100 parts of the solid content of the solution. (manufactured by Mitsubishi Gas Chemical Co., Ltd., trade name "Tetrad C”) 6 parts (solid content) was added and stirred to obtain an acrylic pressure-sensitive adhesive composition according to this example.
  • an epoxy cross-linking agent (B1) per 100 parts of the solid content of the solution.
  • Examples 3 to 6 using a pressure-sensitive adhesive composition containing an acrylic polymer containing C 5-18 linear alkyl (meth)acrylate as a monomer component and a cross-linking agent also, compared to Comparative Example 1 using n-butyl acrylate and Comparative Example 2 using 2-ethylhexyl acrylate, the initial adhesive strength was low when peeled at low speed, and even when peeled at high speed A tendency to suppress the increase in adhesive strength was observed. From the comparison of the results of Examples 1 to 3, it was found that the difference in the molecular weight (Mw) of the acrylic polymer caused a difference in the tendency of the adhesive strength to change over time for high-speed peeling.
  • Mw molecular weight
  • Reference Signs List 1 adhesive sheet 10 support substrate 10A first surface 10B second surface (back surface) 21 adhesive layer 21A adhesive surface 31 release liner 100 adhesive sheet with release liner

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Abstract

Provided is an adhesive agent composition able to form an adhesive agent which is lightly releasable at a low peeling speed and can suppress an increase in peeling force at a high peeling speed. Also provided is an adhesive sheet which is lightly releasable at a low peeling speed and can suppress an increase in peeling force at a high peeling speed. Provided is an adhesive agent composition that contains an acrylic polymer and an epoxy-based crosslinking agent. The acrylic polymer is a polymer of a monomer component containing an alkyl (meth)acrylate having a linear alkyl group with 5-18 carbon atoms at an ester terminal. In addition, an adhesive sheet having an adhesive agent layer having a gel fraction of 70% or more is provided in another embodiment. The adhesive agent layer is formed from an adhesive agent composition containing an acrylic polymer and a crosslinking agent. The acrylic polymer is a polymer of a monomer component containing an alkyl (meth)acrylate having a linear alkyl group with 5-18 carbon atoms at an ester terminal.

Description

粘着剤組成物、粘着剤、粘着シートおよび表面保護フィルムAdhesive composition, adhesive, adhesive sheet and surface protection film
　本発明は、粘着剤組成物、粘着剤、粘着シートおよび表面保護フィルムに関する。本出願は、２０２１年１０月２５日に出願された日本国特許出願２０２１－１７４０５６号に基づく優先権を主張しており、その出願の全内容は本明細書中に参照として組み入れられている。 The present invention relates to an adhesive composition, an adhesive, an adhesive sheet and a surface protection film. This application claims priority based on Japanese Patent Application No. 2021-174056 filed on October 25, 2021, the entire contents of which are incorporated herein by reference.
　一般に、粘着剤（感圧接着剤ともいう。以下同じ。）は室温付近の温度域において柔らかい固体（粘弾性体）の状態を呈し、圧力により簡単に被着体に接着する性質を有する。このような性質を活かして、粘着剤は、粘着シートの形態で、部品の接合や表面保護等の目的で広く利用されている。上記粘着剤は、例えば、アクリル系ポリマーと、架橋剤とを含む粘着剤組成物から形成される。この種の従来技術を開示する先行技術文献として、特許文献１～３が挙げられる。 In general, pressure-sensitive adhesives (also called pressure-sensitive adhesives; the same shall apply hereinafter) exhibit a soft solid (viscoelastic) state in a temperature range near room temperature, and have the property of easily adhering to adherends under pressure. Taking advantage of such properties, adhesives are widely used in the form of adhesive sheets for purposes such as bonding of parts and surface protection. The pressure-sensitive adhesive is formed from, for example, a pressure-sensitive adhesive composition containing an acrylic polymer and a cross-linking agent. Prior art documents disclosing this type of prior art include Patent Documents 1 to 3.
日本国特許第４６８２２９９号公報Japanese Patent No. 4682299 国際公開第２０２１／１２５２７８号WO2021/125278 国際公開第２０２１／１２５２４７号WO2021/125247
　基材の一方の表面に粘着剤層を有する粘着シートは、各種物品を加工したり運搬したりする際に、その表面の損傷（傷や汚れ、腐食等）を防止する表面保護フィルムとしても好ましく利用されている。表面保護フィルム等のように、保護対象物の保護目的を達成した後に保護対象物（被着体）から剥離（再剥離）する使用態様では、粘着剤には、被着体から糊残りなく、スムーズに剥がせるように、軽剥離性が求められる。 A pressure-sensitive adhesive sheet having a pressure-sensitive adhesive layer on one surface of a substrate is also preferable as a surface protective film that prevents surface damage (scratches, stains, corrosion, etc.) during processing or transportation of various articles. It's being used. In a mode of use such as a surface protection film that is peeled off (re-peeled) from the object to be protected (adherend) after achieving the purpose of protecting the object to be protected, the adhesive does not leave adhesive residue on the adherend. Light releasability is required so that it can be peeled off smoothly.
　また、実際の作業現場における再剥離の剥離速度は、低速であったり高速であったりすることが想定される。剥離速度の違いによって剥離力が大きく異なることがあると、剥離作業性に影響を及ぼし、効率的な剥離作業とならない。このため、被着体から再剥離をする使用態様で用いられる粘着剤には、剥離速度の違いによって剥離力が大きく変化しないことも求められる。具体的には、上記粘着剤には、少なくとも低速剥離において軽剥離性を示すことに加えて、高速剥離においても剥離力が低いままに抑えられること（高速剥離における剥離力上昇の抑制）が求められる。 In addition, it is assumed that the peeling speed of re-peeling at the actual work site may be low or high. If the peeling force varies greatly due to the difference in peeling speed, the peeling workability is affected and the peeling work is not efficient. For this reason, it is required that the pressure-sensitive adhesive used in a mode of use in which it is re-peeled from the adherend does not change its peeling force significantly depending on the difference in peeling speed. Specifically, the pressure-sensitive adhesive is required to exhibit light releasability at least in low-speed detachment, and to keep the release force low even in high-speed detachment (suppression of release force increase in high-speed detachment). be done.
　本発明は、上記の事情に鑑みて創出されたものであり、低速剥離における軽剥離性と高速剥離における剥離力上昇の抑制とを実現し得る粘着剤を形成することが可能な粘着剤組成物を提供することを目的とする。また他に、低速剥離における軽剥離性と高速剥離における剥離力上昇の抑制とを実現し得る粘着シートを提供することを目的とする。関連する他の目的は、上記粘着剤組成物から形成された粘着剤、該粘着剤を有する粘着シート、上記粘着シートからなる表面保護フィルムを提供することである。 The present invention was created in view of the above circumstances, and is a pressure-sensitive adhesive composition capable of forming a pressure-sensitive adhesive that can achieve light release properties in low-speed release and suppression of increase in release force in high-speed release. intended to provide Another object of the present invention is to provide a pressure-sensitive adhesive sheet that can achieve light release properties in low-speed release and suppression of increase in release force in high-speed release. Another related object is to provide a pressure-sensitive adhesive formed from the pressure-sensitive adhesive composition, a pressure-sensitive adhesive sheet having the pressure-sensitive adhesive, and a surface protection film comprising the pressure-sensitive adhesive sheet.
　この明細書によると、アクリル系ポリマーと、エポキシ系架橋剤と、を含む粘着剤組成物が提供される。上記アクリル系ポリマーは、炭素数５～１８の直鎖アルキル基をエステル末端に有するアルキル（メタ）アクリレートを含むモノマー成分の重合物である。炭素数５～１８という比較的長い直鎖アルキル基を有するアルキル（メタ）アクリレートの使用により、アルキル基の絡み合いや配向に基づき硬化性が増し、低速剥離時の接着力を低く抑え、かつ高速剥離時の接着力上昇が抑制されやすい。上記モノマーをモノマー単位として含むアクリル系ポリマーと、エポキシ系架橋剤と、を使用することにより、低速剥離における軽剥離性と、高速剥離における剥離力上昇の抑制とが実現される傾向にある。 According to this specification, a pressure-sensitive adhesive composition containing an acrylic polymer and an epoxy-based cross-linking agent is provided. The acrylic polymer is a polymer of a monomer component containing an alkyl (meth)acrylate having a linear alkyl group having 5 to 18 carbon atoms at the ester end. By using an alkyl (meth)acrylate with a relatively long straight-chain alkyl group of 5 to 18 carbon atoms, curability increases due to the entanglement and orientation of the alkyl group, and the adhesive strength during low-speed peeling is kept low, and high-speed peeling is achieved. It is easy to suppress the increase in adhesive strength at time. By using an acrylic polymer containing the above-mentioned monomer as a monomer unit and an epoxy-based cross-linking agent, there is a tendency to achieve light peeling properties in low-speed peeling and suppression of an increase in peel force in high-speed peeling.
　いくつかの好ましい態様において、上記モノマー成分は、さらに（メタ）アクリル酸を含む。アクリル系ポリマーを構成するモノマー成分として（メタ）アクリル酸を用いることにより、架橋剤（例えばエポキシ系架橋剤）との架橋反応が好適に進行して硬化性が増し、低速剥離における軽剥離性を示し、高速剥離における剥離力上昇が抑制され、かつ経時での接着力上昇が抑制され得る粘着剤が形成されやすい。 In some preferred embodiments, the monomer component further contains (meth)acrylic acid. By using (meth)acrylic acid as a monomer component constituting the acrylic polymer, the cross-linking reaction with a cross-linking agent (e.g., an epoxy-based cross-linking agent) proceeds favorably, increasing curability and improving light release properties in low-speed release. It is easy to form a pressure-sensitive adhesive that can suppress an increase in peel strength during high-speed peeling and an increase in adhesive strength over time.
　いくつかの好ましい態様において、上記炭素数５～１８の直鎖アルキル基をエステル末端に有するアルキル（メタ）アクリレートは、ｎ－へプチルアクリレート（ＨｐＡ）を含む。上記炭素数５～１８の直鎖アルキル基をエステル末端に有するアルキル（メタ）アクリレートとしては、ＨｐＡが好ましく用いられる。 In some preferred embodiments, the alkyl (meth)acrylate having a linear alkyl group having 5 to 18 carbon atoms at the ester end includes n-heptyl acrylate (HpA). HpA is preferably used as the alkyl (meth)acrylate having a linear alkyl group having 5 to 18 carbon atoms at the ester end.
　また、この明細書によると、ここに開示されるいずれかの粘着剤組成物から形成された粘着剤が提供される。かかる粘着剤は、低速剥離における軽剥離性を示し、かつ高速剥離における剥離力上昇が抑制されるものになるので、当該粘着剤を被着体に貼り付け、その目的を達成した後、剥離（再剥離）する際に、剥離速度にかかわらず剥離がしやすい。 Also, according to this specification, a pressure-sensitive adhesive formed from any of the pressure-sensitive adhesive compositions disclosed herein is provided. Such an adhesive exhibits light release properties in low-speed peeling and suppresses the increase in peel force in high-speed peeling. Easy to peel off regardless of the peeling speed.
　いくつかの好ましい態様において、上記粘着剤のゲル分率は７０％以上である。ゲル分率が７０％以上である粘着剤は、例えば製造時において、外力による打痕等の変形や損傷が生じにくく、外観の変化が生じにくい。そのような粘着剤は、平滑な表面を有する粘着シートとなりやすく、例えば透明粘着シートに形成して粘着シート越しの被着体検査をする場合に、高精度の検査が可能となり好ましい。また、ゲル分率が高い粘着剤は、低速剥離における軽剥離性を示し、高速剥離における剥離力上昇が抑制され、かつ経時での接着力上昇が抑制され得るため好ましい。 In some preferred embodiments, the adhesive has a gel fraction of 70% or more. A pressure-sensitive adhesive having a gel fraction of 70% or more is less likely to cause deformation or damage such as dents due to external force during production, and less likely to cause changes in appearance. Such a pressure-sensitive adhesive tends to form a pressure-sensitive adhesive sheet having a smooth surface. For example, when a transparent pressure-sensitive adhesive sheet is formed and an adherend is inspected through the pressure-sensitive adhesive sheet, highly accurate inspection is possible, which is preferable. In addition, a PSA with a high gel fraction is preferable because it exhibits light release properties during low-speed release, suppresses an increase in release force during high-speed release, and suppresses an increase in adhesive strength over time.
　また、この明細書によると、ここに開示されるいずれかの粘着剤からなる粘着剤層を有する粘着シートが提供される。ここに開示される粘着シートは、粘着シートの形態で用いられた際に、低速剥離における軽剥離性を示し、かつ高速剥離における剥離力上昇が抑制されるものになるので、剥離速度にかかわらず剥離がしやすい。したがって、表面保護フィルムとして好適である。表面保護フィルムは、保護対象物に貼り付けられた後、その保護目的を達成すると、通常、保護対象物から剥離除去（再剥離）される。ここに開示される粘着剤を表面保護用途に適用することにより、剥離力の剥離速度依存性の少なさに基づき、再剥離時の剥離作業性を向上させることができる。 Further, according to this specification, a pressure-sensitive adhesive sheet having a pressure-sensitive adhesive layer made of any pressure-sensitive adhesive disclosed herein is provided. When used in the form of a pressure-sensitive adhesive sheet, the pressure-sensitive adhesive sheet disclosed herein exhibits light release properties in low-speed peeling and suppresses the increase in peel force in high-speed peeling, so regardless of the peel speed Easy to peel off. Therefore, it is suitable as a surface protection film. After the surface protective film is attached to the object to be protected, it is usually peeled off (re-peeled) from the object to be protected when the protective purpose is achieved. By applying the pressure-sensitive adhesive disclosed herein to surface protection applications, it is possible to improve the peeling workability during re-peeling, based on the low peel speed dependency of the peel force.
　さらに、この明細書によると、ゲル分率が７０％以上である粘着剤層を有する粘着シートが提供される。上記粘着剤層は、アクリル系ポリマーと、架橋剤と、を含む粘着剤組成物から形成されており、上記アクリル系ポリマーは、炭素数５～１８の直鎖アルキル基をエステル末端に有するアルキル（メタ）アクリレートを含むモノマー成分の重合物である。ゲル分率が７０％以上である粘着剤層は、例えば製造時において、外力による打痕等の変形や損傷が生じにくく、外観の変化が生じにくい。そのような粘着剤層を有する粘着シートは、平滑な表面を有しやすく、例えば透明粘着シートとして構成され粘着シート越しの被着体検査をする場合に、高精度の検査が可能となり好ましい。また、上記粘着シートは、低速剥離における軽剥離性を示し、高速剥離における剥離力上昇が抑制され、かつ経時での接着力上昇が抑制され得るものとなる傾向にある。 Furthermore, according to this specification, a pressure-sensitive adhesive sheet having a pressure-sensitive adhesive layer with a gel fraction of 70% or more is provided. The pressure-sensitive adhesive layer is formed from a pressure-sensitive adhesive composition containing an acrylic polymer and a cross-linking agent, and the acrylic polymer is an alkyl ( It is a polymer of monomer components containing meth)acrylate. A pressure-sensitive adhesive layer having a gel fraction of 70% or more is less likely to be deformed or damaged, such as dents due to external force, during production, and is less likely to change in appearance. A pressure-sensitive adhesive sheet having such a pressure-sensitive adhesive layer tends to have a smooth surface, and is preferable because, for example, when an adherend is inspected through the pressure-sensitive adhesive sheet and configured as a transparent pressure-sensitive adhesive sheet, highly accurate inspection is possible. In addition, the pressure-sensitive adhesive sheet tends to exhibit light release properties in low-speed peeling, suppress an increase in peel force in high-speed peeling, and be capable of suppressing an increase in adhesive strength over time.
　いくつかの好ましい態様において、上記架橋剤は、エポキシ系架橋剤を含む。また、上記モノマー成分は、さらに（メタ）アクリル酸を含む。これらのアクリル系ポリマーと架橋剤とを使用することにより、低速剥離における軽剥離性を示し、高速剥離における剥離力上昇が抑制され、かつ経時での接着力上昇が抑制され得る粘着シートが得られやすい。このような粘着シートは、表面保護フィルムとして好適である。表面保護フィルムは、保護対象物に貼り付けられた後、その保護目的を達成すると、通常、保護対象物から剥離除去（再剥離）される。ここに開示される粘着シートを表面保護用途に適用することにより、剥離力の剥離速度依存性の少なさに基づき、再剥離時の剥離作業性を向上させることができる。 In some preferred embodiments, the cross-linking agent includes an epoxy-based cross-linking agent. Moreover, the monomer component further contains (meth)acrylic acid. By using these acrylic polymers and a cross-linking agent, it is possible to obtain a pressure-sensitive adhesive sheet that exhibits light release properties in low-speed peeling, suppresses an increase in peel force in high-speed peeling, and can suppress an increase in adhesive strength over time. Cheap. Such an adhesive sheet is suitable as a surface protection film. After the surface protective film is attached to the object to be protected, it is usually peeled off (re-peeled) from the object to be protected when the protective purpose is achieved. By applying the pressure-sensitive adhesive sheet disclosed herein to surface protection, it is possible to improve the peeling workability at the time of re-peeling, based on the low peel speed dependence of the peel force.
　いくつかの好ましい態様において、表面保護フィルムは、５０℃環境下で３日間エージングした後に引張速度３０ｍ／分で測定される初期高速接着力が３．０Ｎ／２５ｍｍ以下である。この特性を満足する表面保護フィルムは、たとえ被着体である保護対象物から高速で剥離したとしても剥離力が低く抑制されているため、被着体に損傷を与えずに剥離しやすい。 In some preferred embodiments, the surface protective film has an initial high-speed adhesive strength of 3.0 N/25 mm or less measured at a tensile speed of 30 m/min after aging in a 50°C environment for 3 days. A surface protective film that satisfies this property has a low peeling force even if it is peeled off from an object to be protected, which is an adherend, at a high speed.
一実施形態に係る粘着シートの構成を模式的に示す断面図である。1 is a cross-sectional view schematically showing the configuration of a pressure-sensitive adhesive sheet according to one embodiment; FIG.
　以下、本発明の好適な実施形態を説明する。本明細書において特に言及している事項以外の事柄であって本発明の実施に必要な事柄は、本明細書に記載された発明の実施についての教示と出願時の技術常識とに基づいて当業者に理解され得る。本発明は、本明細書に開示されている内容と当該分野における技術常識とに基づいて実施することができる。
　なお、以下の図面において、同じ作用を奏する部材・部位には同じ符号を付して説明することがあり、重複する説明は省略または簡略化することがある。また、図面に記載の実施形態は、本発明を明瞭に説明するために模式化されており、実際に提供される製品のサイズや縮尺を必ずしも正確に表したものではない。 Preferred embodiments of the present invention are described below. Matters other than those specifically referred to in this specification that are necessary for the implementation of the present invention are applicable based on the teaching of the implementation of the invention described in this specification and the common general knowledge at the time of filing. understandable to traders. The present invention can be implemented based on the contents disclosed in this specification and common general technical knowledge in the field.
In the drawings below, members and portions having the same function may be denoted by the same reference numerals, and redundant description may be omitted or simplified. In addition, the embodiments described in the drawings are schematics for the purpose of clearly explaining the present invention and do not necessarily represent the size or scale of the products actually provided.
　この明細書において「粘着剤」とは、前述のように、室温付近の温度域において柔らかい固体（粘弾性体）の状態を呈し、圧力により簡単に被着体に接着する性質を有する材料をいう。ここでいう粘着剤は、「C. A. Dahlquist, “Adhesion: Fundamental and Practice”, McLaren & Sons (1966), p. 143」に定義されているとおり、一般的に、複素引張弾性率Ｅ＊（１Ｈｚ）＜１０７ｄｙｎｅ／ｃｍ２を満たす性質を有する材料（典型的には、２５℃において上記性質を有する材料）であり得る。 As used herein, the term “adhesive” refers to a material that exhibits a soft solid (viscoelastic) state in a temperature range around room temperature and has the property of easily adhering to an adherend under pressure, as described above. . The adhesive as used herein generally has a complex tensile elastic modulus E * (1 Hz) as defined in "C. A. Dahlquist, "Adhesion: Fundamental and Practice", McLaren & Sons (1966), p. 143". It may be a material having properties satisfying <10 7 dyne/cm 2 (typically, a material having the above properties at 25°C).
　この明細書において、バイオマス由来の炭素とは、バイオマス材料、すなわち再生可能な有機資源に由来する材料に由来する炭素（再生可能炭素）を意味する。上記バイオマス材料とは、典型的には、太陽光と水と二酸化炭素とが存在すれば持続的な再生産が可能な生物資源（典型的には、光合成を行う植物）に由来する材料のことをいう。したがって、採掘後の使用によって枯渇する化石資源に由来する材料（化石資源系材料）は、ここでいうバイオマス材料の概念から除かれる。粘着剤組成物および粘着剤のバイオマス炭素比、すなわち該粘着剤組成物および粘着剤に含まれる全炭素に占めるバイオマス由来炭素の割合は、ＡＳＴＭ　Ｄ６８６６に準拠して測定される質量数１４の炭素同位体含有量から見積もることができる。 In this specification, biomass-derived carbon means carbon derived from biomass materials, that is, materials derived from renewable organic resources (renewable carbon). The biomass material is typically a material derived from biological resources (typically photosynthetic plants) that can be sustainably reproduced in the presence of sunlight, water, and carbon dioxide. Say. Therefore, materials derived from fossil resources that are depleted by use after mining (fossil resource-based materials) are excluded from the concept of biomass materials here. The biomass-carbon ratio of the pressure-sensitive adhesive composition and pressure-sensitive adhesive, that is, the ratio of biomass-derived carbon to the total carbon contained in the pressure-sensitive adhesive composition and pressure-sensitive adhesive, is the carbon isotope with a mass number of 14 measured according to ASTM D6866. can be estimated from body content.
　この明細書において「（メタ）アクリル系モノマー」とは、一分子中に少なくとも一つの（メタ）アクリロイル基を有するモノマーをいう。ここで「（メタ）アクリロイル」とは、アクリロイルおよびメタクリロイルを包括的に指す意味である。したがって、ここでいう（メタ）アクリル系モノマーの概念には、アクリロイル基を有するモノマー（アクリル系モノマー）とメタクリロイル基を有するモノマー（メタクリル系モノマー）との両方が包含され得る。この明細書において「（メタ）アクリル酸」とは、アクリル酸およびメタクリル酸を包括的に指す意味である。 "(Meth)acrylic monomer" as used in this specification refers to a monomer having at least one (meth)acryloyl group in one molecule. Here, "(meth)acryloyl" is a generic term for acryloyl and methacryloyl. Therefore, the concept of a (meth)acrylic monomer as used herein can include both a monomer having an acryloyl group (acrylic monomer) and a monomer having a methacryloyl group (methacrylic monomer). In this specification, "(meth)acrylic acid" is meant to comprehensively refer to acrylic acid and methacrylic acid.
　＜粘着剤組成物＞
　（アクリル系ポリマー）
　ここに開示される粘着剤組成物は、アクリル系ポリマーを含有する。ここで「アクリル系ポリマー」とは、（メタ）アクリル系モノマーを５０重量％より多く含むモノマー成分に由来する重合物をいう。モノマー成分における（メタ）アクリル系モノマーの含有量は、好ましくは７０重量％以上であり、８０重量％以上でもよい。いくつかの態様において、モノマー成分における（メタ）アクリル系モノマーの含有量は、９０重量％以上でもよく、９５重量％以上でもよく、１００重量％でもよい。一方、粘着特性のバランスを考慮して、いくつかの態様において、モノマー成分全体のうち（メタ）アクリル系モノマーの割合は、例えば９９重量％未満であってよく、９５重量％未満でもよく、９３重量％未満でもよい。 <Adhesive composition>
(acrylic polymer)
The adhesive composition disclosed here contains an acrylic polymer. Here, "acrylic polymer" refers to a polymer derived from a monomer component containing more than 50% by weight of (meth)acrylic monomer. The content of the (meth)acrylic monomer in the monomer component is preferably 70% by weight or more, and may be 80% by weight or more. In some aspects, the content of the (meth)acrylic monomer in the monomer component may be 90% by weight or more, 95% by weight or more, or 100% by weight. On the other hand, considering the balance of adhesive properties, in some embodiments, the proportion of the (meth)acrylic monomer in the total monomer components may be, for example, less than 99% by weight, may be less than 95% by weight, or may be less than 93% by weight. It may be less than weight percent.
　上記アクリル系ポリマーを構成するモノマー成分は、炭素数５～１８の直鎖アルキル基をエステル末端に有するアルキル（メタ）アクリレート（以下「Ｃ５－１８直鎖アルキル（メタ）アクリレート」ともいう。）を含むことを特徴の一つとする。特に限定するものではないが、炭素数５～１８という比較的長い直鎖アルキル基を有するアルキル（メタ）アクリレートの使用により、アルキル基の絡み合いや配向に基づき硬化性が増し、低速剥離時の接着力を低く抑え、かつ高速剥離時の接着力上昇が抑制されると考えられる。 The monomer component constituting the acrylic polymer is an alkyl (meth)acrylate having a linear alkyl group having 5 to 18 carbon atoms at the ester end (hereinafter also referred to as “C 5-18 linear alkyl (meth)acrylate”). One of the features is to include Although not particularly limited, the use of alkyl (meth)acrylates with relatively long linear alkyl groups of 5 to 18 carbon atoms increases curability based on the entanglement and orientation of the alkyl groups, and adhesion during low-speed peeling. It is thought that the force is kept low and the increase in adhesive strength during high-speed peeling is suppressed.
　上記Ｃ５－１８直鎖アルキル（メタ）アクリレートは、下記式（１）でも表すことができる。
　ＣＨ２＝Ｃ（Ｒ１）ＣＯＯＲ２　　　　　（１）
　ここで、上記式（１）中のＲ１は水素原子またはメチル基である。また、Ｒ２は炭素原子数５～１８の直鎖アルキル基である。Ｃ５－１８直鎖アルキル（メタ）アクリレートが有する直鎖アルキル基の炭素数は、粘着特性の観点から、好ましくは１４以下、より好ましくは１２以下、さらに好ましくは１１以下、特に好ましくは１０以下（例えば９または８以下）である。また、上記炭素数は、アルキル基を長鎖とする作用や特性を効果的に発現させる観点から、好ましくは６以上、より好ましくは７以上である。 The above C 5-18 linear alkyl (meth)acrylate can also be represented by the following formula (1).
CH2 =C( R1 ) COOR2 (1)
Here, R 1 in the above formula (1) is a hydrogen atom or a methyl group. R 2 is a linear alkyl group having 5 to 18 carbon atoms. The number of carbon atoms in the straight-chain alkyl group of the C 5-18 straight-chain alkyl (meth)acrylate is preferably 14 or less, more preferably 12 or less, still more preferably 11 or less, and particularly preferably 10 or less, from the viewpoint of adhesive properties. (eg 9 or 8 or less). In addition, the number of carbon atoms is preferably 6 or more, more preferably 7 or more, from the viewpoint of effectively exhibiting the effect and properties of making the alkyl group longer.
　Ｃ５－１８直鎖アルキル（メタ）アクリレートの具体例としては、ｎ－ペンチル（メタ）アクリレート、ｎ－ヘキシル（メタ）アクリレート、ｎ－ヘプチル（メタ）アクリレート、ｎ－オクチル（メタ）アクリレート、ｎ－ノニル（メタ）アクリレート、ｎ－デシル（メタ）アクリレート、ｎ－ウンデシル（メタ）アクリレート、ｎ－ドデシル（メタ）アクリレート、ｎ－トリデシル（メタ）アクリレート、ｎ－テトラデシル（メタ）アクリレート、ｎ－ペンタデシル（メタ）アクリレート、ｎ－ヘキサデシル（メタ）アクリレート、ｎ－ヘプタデシル（メタ）アクリレート、ｎ－オクタデシル（メタ）アクリレート等が挙げられる。Ｃ５－１８直鎖アルキル（メタ）アクリレートは、１種を単独でまたは２種以上を組み合わせて用いることができる。 Specific examples of C 5-18 linear alkyl (meth)acrylates include n-pentyl (meth)acrylate, n-hexyl (meth)acrylate, n-heptyl (meth)acrylate, n-octyl (meth)acrylate, n -nonyl (meth)acrylate, n-decyl (meth)acrylate, n-undecyl (meth)acrylate, n-dodecyl (meth)acrylate, n-tridecyl (meth)acrylate, n-tetradecyl (meth)acrylate, n-pentadecyl (Meth)acrylate, n-hexadecyl (meth)acrylate, n-heptadecyl (meth)acrylate, n-octadecyl (meth)acrylate and the like. The C 5-18 linear alkyl (meth)acrylates can be used singly or in combination of two or more.
　モノマー成分全体のうちＣ５－１８直鎖アルキル（メタ）アクリレートの割合は、その使用目的や要求特性等に応じて設定され、例えば１重量％以上であってもよく、１０重量％以上が適当であり、好ましくは３０重量％以上、より好ましくは５０重量％以上（例えば５０重量％超）であり、７０重量％以上でもよく、８０重量％以上でもよく、８５重量％以上でもよく、９０重量％以上でもよく、９２重量％以上でもよく、９５重量％以上でもよい。Ｃ５－１８直鎖アルキル（メタ）アクリレートの使用量を増大することにより、Ｃ５－１８直鎖アルキル（メタ）アクリレートに基づく特性を効果的に発現させることができる。一方、架橋点となる官能基含有アクリル系モノマーや、その他のモノマーを共重合する観点から、モノマー成分全体のうちＣ５－１８直鎖アルキル（メタ）アクリレートの割合は、例えば９９重量％未満であってよく、９８重量％未満でもよく、９７重量％未満でもよい。他のいくつかの態様において、モノマー成分全体に占めるＣ５－１８直鎖アルキル（メタ）アクリレートの割合の上限は、他のモノマーの使用効果を得る観点から、９５重量％以下であってもよく、７５重量％以下でもよく、６０重量％以下でもよく、５０重量％以下（例えば５０重量％未満）でもよく、３０重量％以下でもよい。 The proportion of the C5-18 straight-chain alkyl (meth)acrylate in the total monomer components is set according to the purpose of use, required properties, etc., and may be, for example, 1% by weight or more, preferably 10% by weight or more. , preferably 30% by weight or more, more preferably 50% by weight or more (for example, more than 50% by weight), may be 70% by weight or more, may be 80% by weight or more, may be 85% by weight or more, or may be 90% by weight % or more, 92% by weight or more, or 95% by weight or more. By increasing the amount of the C 5-18 linear alkyl (meth)acrylate used, the properties based on the C 5-18 linear alkyl (meth)acrylate can be effectively exhibited. On the other hand, from the viewpoint of copolymerizing functional group-containing acrylic monomers that serve as cross-linking points and other monomers, the proportion of C 5-18 linear alkyl (meth)acrylate in the total monomer components is, for example, less than 99% by weight. may be less than 98% by weight, less than 97% by weight. In some other embodiments, the upper limit of the proportion of C 5-18 linear alkyl (meth)acrylate in the total monomer component may be 95% by weight or less from the viewpoint of obtaining the effect of using other monomers. , 75% by weight or less, 60% by weight or less, 50% by weight or less (for example, less than 50% by weight), or 30% by weight or less.
　上記アクリル系ポリマーのモノマー成分として含まれる鎖状アルキル基をエステル末端に有するアルキル（メタ）アクリレート（以下、単に「鎖状アルキル（メタ）アクリレート」ともいう。）全体に占めるＣ５－１８直鎖アルキル（メタ）アクリレートの割合は、例えば１重量％以上であってもよく、１０重量％以上が適当であり、好ましくは３０重量％以上、より好ましくは５０重量％以上（例えば５０重量％超）であり、７０重量％以上でもよく、８０重量％以上でもよく、９０重量％以上でもよく、９５重量％以上でもよく、９９重量％以上でもよい。なお、上記鎖状アルキル基は、直鎖状および分岐状のアルキル基を包含する概念であり、脂環式と称される環状アルキル基は含まない。Ｃ５－１８直鎖アルキル（メタ）アクリレートの使用量を増大することにより、Ｃ５－１８直鎖アルキル（メタ）アクリレートに基づく特性を効果的に発現させることができる。ここに開示される技術は、鎖状アルキル（メタ）アクリレートとして、Ｃ５－１８直鎖アルキル（メタ）アクリレートのみを含むモノマー組成のアクリル系ポリマーを用いる態様で好ましく実施され得る。したがって、上記鎖状アルキル（メタ）アクリレート全体に占めるＣ５－１８直鎖アルキル（メタ）アクリレートの割合の上限は１００重量％である。他のいくつかの態様において、上記鎖状アルキル（メタ）アクリレート全体に占めるＣ５－１８直鎖アルキル（メタ）アクリレートの割合は、Ｃ５－１８直鎖アルキル（メタ）アクリレート以外の鎖状アルキル（メタ）アクリレートの使用効果を得る観点から、９５重量％以下であってもよく、７５重量％以下でもよく、６０重量％以下でもよく、５０重量％以下（例えば５０重量％未満）でもよく、３０重量％以下でもよい。 Alkyl (meth)acrylate having a chain alkyl group at the ester end (hereinafter also simply referred to as "chain alkyl (meth)acrylate") contained as a monomer component of the acrylic polymer above C 5-18 straight chain accounts for the whole The proportion of alkyl (meth)acrylate may be, for example, 1% by weight or more, suitably 10% by weight or more, preferably 30% by weight or more, more preferably 50% by weight or more (for example, more than 50% by weight). and may be 70% by weight or more, 80% by weight or more, 90% by weight or more, 95% by weight or more, or 99% by weight or more. The above-mentioned chain alkyl group is a concept that includes linear and branched alkyl groups, and does not include cyclic alkyl groups called alicyclic. By increasing the amount of the C 5-18 linear alkyl (meth)acrylate used, the properties based on the C 5-18 linear alkyl (meth)acrylate can be effectively exhibited. The technology disclosed herein can be preferably practiced in a mode using an acrylic polymer having a monomer composition containing only C 5-18 linear alkyl (meth)acrylate as the chain alkyl (meth)acrylate. Therefore, the upper limit of the ratio of C 5-18 straight-chain alkyl (meth)acrylate to the whole chain alkyl (meth)acrylate is 100% by weight. In some other aspects, the ratio of C 5-18 straight chain alkyl (meth ) acrylates to the total chain alkyl (meth)acrylate is From the viewpoint of obtaining the effect of using (meth) acrylate, it may be 95% by weight or less, 75% by weight or less, 60% by weight or less, or 50% by weight or less (for example, less than 50% by weight). It may be 30% by weight or less.
　いくつかの態様において、Ｃ５－１８直鎖アルキル（メタ）アクリレートとして、１種または２種以上のＣ５－１１直鎖アルキル（メタ）アクリレートと、１種または２種以上のＣ１２－１８直鎖アルキル（メタ）アクリレートとを併用してもよい。かかる態様において、両者の使用比率は、粘着特性や、各モノマーのアルキル基に基づく作用、特性等に応じて設定され得る。例えば、Ｃ５－１８直鎖アルキル（メタ）アクリレートに占めるＣ５－１１直鎖アルキル（メタ）アクリレートの割合は、例えば１重量％以上であってもよく、１０重量％以上でもよく、３０重量％以上でもよく、５０重量％以上でもよく、７０重量％以上でもよく、９０重量％以上でもよく、９９重量％以上でもよい。また、Ｃ５－１８直鎖アルキル（メタ）アクリレートに占めるＣ５－１１直鎖アルキル（メタ）アクリレートの割合は、９９重量％以下であってもよく、９０重量％以下でもよく、８０重量％以下でもよい。 In some embodiments, the C 5-18 linear alkyl (meth)acrylates include one or more C 5-11 linear alkyl (meth)acrylates and one or more C 12-18 You may use together with a linear alkyl (meth)acrylate. In such an embodiment, the ratio of the two to be used can be set according to the adhesive property, the action and properties based on the alkyl group of each monomer, and the like. For example, the proportion of C 5-11 linear alkyl (meth)acrylate in C 5-18 linear alkyl (meth)acrylate may be, for example, 1% by weight or more, 10% by weight or more, or 30% by weight. % or more, 50 wt% or more, 70 wt% or more, 90 wt% or more, or 99 wt% or more. Further, the proportion of C 5-11 linear alkyl (meth)acrylate in C 5-18 linear alkyl (meth)acrylate may be 99% by weight or less, may be 90% by weight or less, or may be 80% by weight. It can be below.
　上記Ｃ５－１１直鎖アルキル（メタ）アクリレートとしては、炭素数が１０以下（より好ましくは９以下、例えば８以下、好適には７）の直鎖アルキル基をエステル末端に有するアルキル（メタ）アクリレートが好ましく用いられる。上記直鎖アルキル基の炭素数は、好ましくは６以上である。 The above C 5-11 linear alkyl (meth)acrylate is an alkyl (meth) having a linear alkyl group having 10 or less carbon atoms (more preferably 9 or less, for example 8 or less, preferably 7) at the ester end. Acrylates are preferably used. The straight-chain alkyl group preferably has 6 or more carbon atoms.
　いくつかの好ましい態様では、Ｃ５－１８直鎖アルキル（メタ）アクリレートとして、ｎ－ヘプチル（メタ）アクリレートが用いられる。ｎ－ヘプチル（メタ）アクリレートを使用することにより、ここに開示される技術による効果は特に好ましく発揮され得る。なかでも、粘着特性の観点から、ｎ－ヘプチルアクリレートが特に好ましい。 In some preferred embodiments, n-heptyl (meth)acrylate is used as the C 5-18 linear alkyl (meth)acrylate. By using n-heptyl (meth)acrylate, the effects of the technology disclosed herein can be exhibited particularly favorably. Among them, n-heptyl acrylate is particularly preferable from the viewpoint of adhesive properties.
　モノマー成分全体のうちｎ－ヘプチル（メタ）アクリレートの割合は、その使用目的や要求特性等に応じて設定され、例えば１重量％以上であってもよく、１０重量％以上が適当であり、好ましくは３０重量％以上、より好ましくは５０重量％以上（例えば５０重量％超）であり、７０重量％以上でもよく、８０重量％以上でもよく、８５重量％以上でもよく、９０重量％以上でもよく、９２重量％以上でもよく、９５重量％以上でもよい。ｎ－ヘプチル（メタ）アクリレートの使用量を増大することにより、その使用効果を効果的に発現させることができる。一方、架橋点となる官能基含有アクリル系モノマーや、その他のモノマーを共重合する観点から、モノマー成分全体のうちｎ－ヘプチル（メタ）アクリレートの割合は、例えば９９重量％未満であってよく、９８重量％未満でもよく、９７重量％未満でもよい。他のいくつかの態様において、上記モノマー成分全体に占めるｎ－ヘプチル（メタ）アクリレートの割合は、ｎ－ヘプチル（メタ）アクリレート以外の各種モノマーの使用効果を得る観点から、９５重量％以下であってもよく、７５重量％以下でもよく、６０重量％以下でもよく、５０重量％以下（例えば５０重量％未満）でもよく、３０重量％以下でもよい。 The ratio of n-heptyl (meth)acrylate in the total monomer components is set according to the purpose of use, required properties, etc., and may be, for example, 1% by weight or more, preferably 10% by weight or more. is 30% by weight or more, more preferably 50% by weight or more (for example, more than 50% by weight), may be 70% by weight or more, may be 80% by weight or more, may be 85% by weight or more, or may be 90% by weight or more. , 92% by weight or more, or 95% by weight or more. By increasing the amount of n-heptyl (meth)acrylate used, the effect of use can be effectively exhibited. On the other hand, from the viewpoint of copolymerizing functional group-containing acrylic monomers that serve as cross-linking points and other monomers, the proportion of n-heptyl (meth) acrylate in the total monomer components may be, for example, less than 99% by weight. It may be less than 98 wt%, or less than 97 wt%. In some other embodiments, the proportion of n-heptyl(meth)acrylate in the total monomer components is 95% by weight or less from the viewpoint of obtaining the effect of using various monomers other than n-heptyl(meth)acrylate. 75% by weight or less, 60% by weight or less, 50% by weight or less (for example, less than 50% by weight), or 30% by weight or less.
　上記アクリル系ポリマーのモノマー成分として含まれる鎖状アルキル（メタ）アクリレート全体に占めるｎ－ヘプチル（メタ）アクリレートの割合は、例えば１重量％以上であってもよく、１０重量％以上が適当であり、好ましくは３０重量％以上、より好ましくは５０重量％以上（例えば５０重量％超）であり、７０重量％以上でもよく、８０重量％以上でもよく、９０重量％以上でもよく、９５重量％以上でもよく、９９重量％以上でもよい。ｎ－ヘプチル（メタ）アクリレートの使用量を増大することにより、その使用効果を効果的に発現させることができる。ここに開示される技術は、上記鎖状アルキル（メタ）アクリレートとして、ｎ－ヘプチル（メタ）アクリレートのみを含むモノマー組成のアクリル系ポリマーを用いる態様で好ましく実施され得る。したがって、上記鎖状アルキル（メタ）アクリレート全体に占めるｎ－ヘプチル（メタ）アクリレートの割合の上限は１００重量％である。他のいくつかの態様において、上記鎖状アルキル（メタ）アクリレート全体に占めるｎ－ヘプチル（メタ）アクリレートの割合は、他の鎖状アルキル（メタ）アクリレートの使用効果を得る観点から、９５重量％以下であってもよく、７５重量％以下でもよく、６０重量％以下でもよく、５０重量％以下（例えば５０重量％未満）でもよく、３０重量％以下でもよい。 The ratio of n-heptyl (meth)acrylate to the total linear alkyl (meth)acrylate contained as a monomer component of the acrylic polymer may be, for example, 1% by weight or more, and is suitably 10% by weight or more. , preferably 30% by weight or more, more preferably 50% by weight or more (for example, more than 50% by weight), may be 70% by weight or more, may be 80% by weight or more, may be 90% by weight or more, or may be 95% by weight or more , or 99% by weight or more. By increasing the amount of n-heptyl (meth)acrylate used, the effect of use can be effectively exhibited. The technology disclosed herein can be preferably implemented in a mode using an acrylic polymer having a monomer composition containing only n-heptyl (meth)acrylate as the chain alkyl (meth)acrylate. Therefore, the upper limit of the ratio of n-heptyl (meth)acrylate to the total chain alkyl (meth)acrylate is 100% by weight. In some other embodiments, the ratio of n-heptyl (meth)acrylate to the total chain alkyl (meth)acrylate is 95% by weight from the viewpoint of obtaining the effect of using other chain alkyl (meth)acrylate. 75% by weight or less, 60% by weight or less, 50% by weight or less (for example, less than 50% by weight), or 30% by weight or less.
　いくつかの態様において、アクリル系ポリマーを構成するモノマー成分は、炭素数１９以上の鎖状アルキル基をエステル末端に有するアルキル（メタ）アクリレート（Ｃ１９以上鎖状アルキル（メタ）アクリレート）を含んでもよく、含まなくてもよい。Ｃ１９以上鎖状アルキル（メタ）アクリレートは、１種を単独でまたは２種以上を組み合わせて用いることができる。上記モノマー成分に含まれる鎖状アルキル（メタ）アクリレート全体に占めるＣ１９以上鎖状アルキル（メタ）アクリレートの割合は、例えば９０重量％以下であってもよく、７０重量％以下でもよく、５０重量％以下（例えば５０重量％未満）でもよく、３０重量％以下でもよく、１０重量％以下でもよく、１重量％以下でもよい。ここに開示される技術は、モノマー成分がＣ１９以上鎖状アルキル（メタ）アクリレートを実質的に含まない態様で好ましく実施され得る。 In some aspects, the monomer component constituting the acrylic polymer may contain an alkyl (meth)acrylate having a chain alkyl group with 19 or more carbon atoms at the ester end (chain alkyl (meth)acrylate with 19 or more carbon atoms). , may not be included. The C19 or higher chain alkyl (meth)acrylates may be used singly or in combination of two or more. The ratio of the C19 or higher chain alkyl (meth)acrylate to the total chain alkyl (meth)acrylate contained in the monomer component may be, for example, 90% by weight or less, 70% by weight or less, or 50% by weight. or less (for example, less than 50% by weight), 30% by weight or less, 10% by weight or less, or 1% by weight or less. The technique disclosed herein can be preferably implemented in a mode in which the monomer component does not substantially contain C19 or higher chain alkyl (meth)acrylate.
　いくつかの態様において、上記モノマー成分は、上記鎖状アルキル（メタ）アクリレートとして、バイオマス由来のアルキル基をエステル末端に有するアルキル（メタ）アクリレート（以下「バイオマス鎖状アルキル（メタ）アクリレート」ともいう。）を含み得る。近年、地球温暖化等の環境問題が重視されるようになり、石油等の化石資源系材料の使用量を低減することが望まれている。このような状況下、粘着剤の分野においても化石資源系材料の使用量を低減することが求められている。バイオマス鎖状アルキル（メタ）アクリレートを用いることにより、化石資源系材料への依存抑制に配慮されたアクリル系粘着剤組成物を好適に実現することができる。 In some embodiments, the monomer component is an alkyl (meth)acrylate having a biomass-derived alkyl group at the ester end (hereinafter also referred to as "biomass chain alkyl (meth)acrylate") as the chain alkyl (meth)acrylate. .). In recent years, environmental problems such as global warming have come to be emphasized, and it is desired to reduce the amount of fossil resource-based materials such as petroleum used. Under such circumstances, it is required to reduce the amount of fossil resource-based materials used in the field of pressure-sensitive adhesives as well. By using a biomass chain-shaped alkyl (meth)acrylate, it is possible to suitably realize an acrylic pressure-sensitive adhesive composition that is less dependent on fossil resource-based materials.
　バイオマス鎖状アルキル（メタ）アクリレートは、特に限定されず、例えば、バイオマス由来のアルカノールと、バイオマス由来または非バイオマス由来の（メタ）アクリル酸とのエステルである。バイオマス由来のアルカノールの例には、バイオマスエタノール、パーム油やパーム核油、ヤシ油、ヒマシ油等の植物原料に由来するアルカノール、等が含まれる。バイオマス由来のアルカノールの炭素原子数が３以上である場合、該アルカノールは、直鎖状であってもよく、分岐を有していてもよい。いくつかの態様において、アクリル系ポリマーの合成に用いられるバイオマス鎖状アルキル（メタ）アクリレートとして、バイオマス由来のアルカノールと、非バイオマス由来の（メタ）アクリル酸とのエステルが用いられる。かかるバイオマス鎖状アルキル（メタ）アクリレートでは、アルカノールの炭素原子数が多いほど、該バイオマス鎖状アルキル（メタ）アクリレートに含まれる総炭素数に占めるバイオマス由来炭素の個数割合、すなわち該鎖状アルキル（メタ）アクリレートのバイオマス炭素比が高くなる。したがって、上記のバイオマス鎖状アルキル（メタ）アクリレートでは、バイオマス由来となる鎖状アルキル基の炭素数が多いことが、化石資源系材料への依存度低減の点で望ましい。その一方で、鎖状アルキル（メタ）アクリレートを構成する鎖状アルキル基の炭素数が多すぎると、接着力等の粘着特性が得られにくくなる傾向があり、また合成や取扱い性、コストなど生産性の点でも不利になり得る。バイオマス鎖状アルキル（メタ）アクリレートとして、バイオマス由来のアルカノールと、非バイオマス由来の（メタ）アクリル酸とのエステルを用いる態様では、粘着特性と、化石資源系材料への依存度低減（より具体的には上記鎖状アルキル（メタ）アクリレートのバイオマス炭素比）とをバランスよく両立する材料を用いることが望ましい。 The biomass chain alkyl (meth)acrylate is not particularly limited, and is, for example, an ester of a biomass-derived alkanol and a biomass-derived or non-biomass-derived (meth)acrylic acid. Examples of biomass-derived alkanols include biomass ethanol, alkanols derived from plant sources such as palm oil, palm kernel oil, coconut oil, castor oil, and the like. When the number of carbon atoms in the biomass-derived alkanol is 3 or more, the alkanol may be linear or branched. In some embodiments, an ester of a biomass-derived alkanol and a non-biomass-derived (meth)acrylic acid is used as the biomass linear alkyl (meth)acrylate used to synthesize the acrylic polymer. In such a biomass chain alkyl (meth)acrylate, the greater the number of carbon atoms in the alkanol, the more the number of biomass-derived carbons accounts for the total number of carbon atoms contained in the biomass chain alkyl (meth)acrylate, that is, the chain alkyl ( The biomass carbon ratio of meth)acrylate is increased. Therefore, in the biomass chain alkyl (meth)acrylate described above, it is desirable that the chain alkyl group derived from biomass has a large number of carbon atoms in order to reduce dependence on fossil resource-based materials. On the other hand, if the number of carbon atoms in the chain alkyl group that constitutes the chain alkyl (meth)acrylate is too large, it tends to be difficult to obtain adhesive properties such as adhesive strength. It can also be disadvantageous in terms of gender. In an embodiment using an ester of a biomass-derived alkanol and a non-biomass-derived (meth)acrylic acid as the biomass linear alkyl (meth)acrylate, adhesive properties and reduced dependence on fossil resource-based materials (more specifically It is desirable to use a material that balances well with the biomass carbon ratio of the chain alkyl (meth)acrylate.
　ここに開示される技術においては、上述のＣ５－１８直鎖アルキル（メタ）アクリレート、Ｃ１－４鎖状アルキル（メタ）アクリレート、Ｃ５－１８分岐アルキル（メタ）アクリレート、Ｃ１９以上鎖状アルキル（メタ）アクリレートのいずれにも、バイオマス鎖状アルキル（メタ）アクリレートを用いることができる。Ｃ５－１８直鎖アルキル（メタ）アクリレートとして、バイオマス鎖状アルキル（メタ）アクリレートを用いる態様においては、上述のＣ５－１１直鎖アルキル（メタ）アクリレートとして、バイオマス鎖状アルキル（メタ）アクリレートを用いてもよく、上述のＣ１２－１８直鎖アルキル（メタ）アクリレートとしてバイオマス鎖状アルキル（メタ）アクリレートを用いてもよい。アクリル系ポリマーの合成に用いられる鎖状アルキル（メタ）アクリレートとして、２種以上の化合物を用いる態様においては、少なくともその一部（例えば１種または２種、あるいは全部、すなわち全種）をバイオマス鎖状アルキル（メタ）アクリレートとすることができる。 In the technology disclosed herein, the above C 5-18 linear alkyl (meth)acrylate, C 1-4 chain alkyl (meth)acrylate, C 5-18 branched alkyl (meth)acrylate, C 19 or higher chain alkyl (meth)acrylate, A biomass chain-like alkyl (meth)acrylate can be used for any of the alkyl (meth)acrylates. In an embodiment using a biomass chain alkyl (meth)acrylate as the C 5-18 straight chain alkyl (meth)acrylate, a biomass chain alkyl (meth)acrylate is used as the C 5-11 straight chain alkyl (meth)acrylate may be used, and a biomass chain alkyl (meth)acrylate may be used as the above C 12-18 linear alkyl (meth)acrylate. In embodiments in which two or more types of compounds are used as the chain alkyl (meth)acrylates used in synthesizing the acrylic polymer, at least a portion thereof (e.g., one or two types, or all, i.e., all types) are biomass chains. Alkyl (meth)acrylates can be used.
　いくつかの好ましい態様において、Ｃ５－１８直鎖アルキル（メタ）アクリレートとして、バイオマス由来のＣ５－１８直鎖アルキル基をエステル末端に有するアルキル（メタ）アクリレート（以下「バイオマスＣ５－１８直鎖アルキル（メタ）アクリレート」ともいう。）の１種または２種以上が用いられる。バイオマスＣ５－１８直鎖アルキル（メタ）アクリレートを用いることにより、化石資源系材料への依存度を低減しつつ、ここに開示される技術による効果（低速剥離における接着力を低くし、高速剥離における剥離力上昇を抑制する効果等）が好ましく実現される。上記バイオマスＣ５－１８直鎖アルキル（メタ）アクリレートは、バイオマス由来のアルカノールと、バイオマス由来または非バイオマス由来の（メタ）アクリル酸とのエステルであり、例えば、バイオマス由来のアルカノールと非バイオマス由来の（メタ）アクリル酸とのエステルが用いられ得る。かかる化合物では、直鎖アルキル基のみがバイオマス由来となる。 In some preferred embodiments, the C 5-18 linear alkyl (meth)acrylate is an alkyl (meth)acrylate having a biomass-derived C 5-18 linear alkyl group at the ester end (hereinafter “biomass C 5-18 linear (also referred to as "chain alkyl (meth)acrylate") is used. By using biomass C 5-18 linear alkyl (meth)acrylate, while reducing dependence on fossil resource-based materials, the effects of the technology disclosed here (lower adhesive force in low-speed peeling, high-speed peeling The effect of suppressing the increase in peeling force in ( ) is preferably realized. The biomass C 5-18 linear alkyl (meth)acrylates are esters of biomass-derived alkanols with biomass-derived or non-biomass-derived (meth)acrylic acid, e.g. Esters with (meth)acrylic acid may be used. In such compounds, only the linear alkyl groups are derived from biomass.
　バイオマスＣ５－１８直鎖アルキル（メタ）アクリレートが有する直鎖アルキル基の炭素数は、粘着特性の観点から、好ましくは１４以下、より好ましくは１２以下、さらに好ましくは１１以下、特に好ましくは１０以下（例えば９または８以下）である。また、上記炭素数は、好ましくは５以上、より好ましくは６以上、さらに好ましくは７以上である。例えば、バイオマスＣ５－１８直鎖アルキル（メタ）アクリレートとして、バイオマス由来のアルカノールと非バイオマス由来の（メタ）アクリル酸とのエステルを用いる態様において、直鎖アルキル基の炭素数を多くすることにより、合成されるアクリル系ポリマーのバイオマス炭素比を高めることができる。 The number of carbon atoms in the straight-chain alkyl group of the biomass C 5-18 straight-chain alkyl (meth)acrylate is preferably 14 or less, more preferably 12 or less, still more preferably 11 or less, and particularly preferably 10, from the viewpoint of adhesive properties. or less (eg 9 or 8 or less). Also, the number of carbon atoms is preferably 5 or more, more preferably 6 or more, and still more preferably 7 or more. For example, in an embodiment using an ester of a biomass-derived alkanol and a non-biomass-derived (meth)acrylic acid as the biomass C 5-18 linear alkyl (meth)acrylate, by increasing the carbon number of the linear alkyl group , the biomass carbon ratio of the synthesized acrylic polymer can be increased.
　上記アクリル系ポリマーのモノマー成分として用いられるＣ５－１８直鎖アルキル（メタ）アクリレート全体に占めるバイオマスＣ５－１８直鎖アルキル（メタ）アクリレートの割合は、例えば１重量％以上であってもよく、１０重量％以上が適当であり、好ましくは３０重量％以上、より好ましくは５０重量％以上（例えば５０重量％超）であり、７０重量％以上でもよく、８０重量％以上でもよく、９０重量％以上でもよく、９５重量％以上でもよく、９９重量％以上でもよい。バイオマスＣ５－１８直鎖アルキル（メタ）アクリレートの使用割合を高めることにより、アクリル系ポリマーのバイオマス炭素比を向上させつつ、その使用効果を効果的に発現させることができる。ここに開示される技術は、Ｃ５－１８直鎖アルキル（メタ）アクリレートとして、バイオマスＣ５－１８直鎖アルキル（メタ）アクリレートのみを含むモノマー組成のアクリル系ポリマーを用いる態様で好ましく実施され得る。したがって、上記Ｃ５－１８直鎖アルキル（メタ）アクリレート全体に占めるバイオマスＣ５－１８直鎖アルキル（メタ）アクリレートの割合の上限は１００重量％である。他のいくつかの態様において、Ｃ５－１８直鎖アルキル（メタ）アクリレート全体に占めるバイオマスＣ５－１８直鎖アルキル（メタ）アクリレートの割合は、９５重量％以下であってもよく、７０重量％以下でもよく、５０重量％以下（例えば５０重量％未満）でもよく、３０重量％以下でもよく、１０重量％以下でもよく、１重量％以下でもよい。 The ratio of the biomass C5-18 straight-chain alkyl (meth)acrylate to the total C5-18 straight-chain alkyl (meth)acrylate used as the monomer component of the acrylic polymer may be, for example, 1% by weight or more. , 10% by weight or more is suitable, preferably 30% by weight or more, more preferably 50% by weight or more (for example, more than 50% by weight); % or more, 95% by weight or more, or 99% by weight or more. By increasing the proportion of the biomass C 5-18 linear alkyl (meth)acrylate used, the effect of use can be effectively exhibited while improving the biomass carbon ratio of the acrylic polymer. The technology disclosed herein can be preferably implemented in a mode using an acrylic polymer having a monomer composition containing only biomass C 5-18 linear alkyl (meth)acrylate as the C 5-18 linear alkyl (meth)acrylate. . Therefore, the upper limit of the ratio of biomass C 5-18 linear alkyl (meth)acrylate to the total C 5-18 linear alkyl (meth)acrylate is 100% by weight. In some other embodiments, the proportion of biomass C 5-18 linear alkyl (meth)acrylates in total C 5-18 linear alkyl (meth)acrylates may be 95% by weight or less, and may be 70% by weight. % or less, 50 wt % or less (for example, less than 50 wt %), 30 wt % or less, 10 wt % or less, or 1 wt % or less.
　いくつかの態様において、バイオマスＣ５－１８直鎖アルキル（メタ）アクリレートとして、１種または２種以上のＣ５－１１直鎖アルキル（メタ）アクリレート（以下「バイオマスＣ５－１１直鎖アルキル（メタ）アクリレート」ともいう。）と、１種または２種以上のＣ１２－１８直鎖アルキル（メタ）アクリレートとを併用してもよい。かかる態様において、Ｃ１２－１８直鎖アルキル（メタ）アクリレートは、バイオマス由来の直鎖アルキル基を有するもの（バイオマスＣ１２－１８直鎖アルキル（メタ）アクリレート）であってもよく、非バイオマス由来の直鎖アルキル基を有するものであってもよい。アクリル系ポリマーのバイオマス炭素比を高める観点から、Ｃ５－１１直鎖アルキル（メタ）アクリレートおよびＣ１２－１８直鎖アルキル（メタ）アクリレートがともにバイオマス由来の材料であることが好ましい。例えば、Ｃ５－１８直鎖アルキル（メタ）アクリレートに占めるバイオマスＣ５－１１直鎖アルキル（メタ）アクリレートの割合は、例えば１重量％以上であってもよく、１０重量％以上でもよく、３０重量％以上でもよく、５０重量％以上でもよく、７０重量％以上でもよく、９０重量％以上でもよく、９９重量％以上でもよい。また、Ｃ５－１８直鎖アルキル（メタ）アクリレートに占めるバイオマスＣ５－１１直鎖アルキル（メタ）アクリレートの割合は、９９重量％以下であってもよく、９０重量％以下でもよく、７０重量％以下でもよく、５０重量％以下でもよく、３０重量％以下でもよく、１０重量％以下でもよく、１重量％以下でもよい。 In some embodiments, the biomass C 5-18 linear alkyl (meth)acrylates include one or more C 5-11 linear alkyl (meth)acrylates (hereinafter “biomass C 5-11 linear alkyl (meth)acrylates meth)acrylate”) and one or more C 12-18 linear alkyl (meth)acrylates may be used in combination. In such embodiments, the C 12-18 linear alkyl (meth)acrylate may be one having a biomass-derived linear alkyl group (biomass C 12-18 linear alkyl (meth)acrylate), or a non-biomass-derived may have a straight-chain alkyl group. From the viewpoint of increasing the biomass carbon ratio of the acrylic polymer, both the C 5-11 linear alkyl (meth)acrylate and the C 12-18 linear alkyl (meth)acrylate are preferably biomass-derived materials. For example, the ratio of biomass C 5-11 linear alkyl (meth)acrylate to C 5-18 linear alkyl (meth)acrylate may be, for example, 1% by weight or more, 10% by weight or more, or 30% by weight or more. It may be at least 50% by weight, at least 70% by weight, at least 90% by weight, or at least 99% by weight. In addition, the proportion of biomass C5-11 linear alkyl (meth)acrylate in C5-18 linear alkyl (meth)acrylate may be 99% by weight or less, may be 90% by weight or less, and may be 70% by weight. % or less, 50 wt% or less, 30 wt% or less, 10 wt% or less, or 1 wt% or less.
　いくつかの好ましい態様では、Ｃ５－１８直鎖アルキル（メタ）アクリレートとして、バイオマス由来のｎ－ヘプチル基を有するｎ－ヘプチル（メタ）アクリレート（以下「バイオマスヘプチル（メタ）アクリレート」ともいう。）が用いられる。バイオマスヘプチル（メタ）アクリレートを使用することにより、化石資源系材料への依存度を低減しつつ、ここに開示される技術による効果が特に好ましく発揮され得る。なかでも、粘着特性の観点から、バイオマスヘプチルアクリレートが特に好ましい。 In some preferred embodiments, the C 5-18 linear alkyl (meth)acrylate is n-heptyl (meth)acrylate having a biomass-derived n-heptyl group (hereinafter also referred to as “biomass heptyl (meth)acrylate”). is used. By using biomass heptyl (meth)acrylate, the effects of the technology disclosed herein can be exhibited particularly favorably while reducing dependence on fossil resource-based materials. Among them, biomass heptyl acrylate is particularly preferable from the viewpoint of adhesive properties.
　上記アクリル系ポリマーのモノマー成分として用いられるＣ５－１８直鎖アルキル（メタ）アクリレート全体に占めるバイオマスヘプチル（メタ）アクリレートの割合は、例えば１重量％以上であってもよく、１０重量％以上が適当であり、好ましくは３０重量％以上、より好ましくは５０重量％以上（例えば５０重量％超）であり、７０重量％以上でもよく、８０重量％以上でもよく、８５重量％以上でもよく、９０重量％以上でもよく、９２重量％以上でもよく、９５重量％以上でもよい。バイオマスヘプチル（メタ）アクリレートの使用割合を高めることにより、アクリル系ポリマーのバイオマス炭素比を向上させつつ、その使用効果を効果的に発現させることができる。ここに開示される技術は、Ｃ５－１８直鎖アルキル（メタ）アクリレートとして、バイオマスヘプチル（メタ）アクリレートのみを含むモノマー組成のアクリル系ポリマーを用いる態様で好ましく実施され得る。したがって、上記Ｃ５－１８直鎖アルキル（メタ）アクリレート全体に占めるバイオマスヘプチル（メタ）アクリレートの割合の上限は１００重量％である。他のいくつかの態様において、Ｃ５－１８直鎖アルキル（メタ）アクリレート全体に占めるバイオマスヘプチル（メタ）アクリレートの割合は、９５重量％以下であってもよく、７５重量％以下でもよく、６０重量％以下でもよく、５０重量％以下（例えば５０重量％未満）でもよく、３０重量％以下でもよく、１０重量％以下でもよく、１重量％以下でもよい。 The ratio of biomass heptyl (meth)acrylate to the total C 5-18 linear alkyl (meth)acrylate used as the monomer component of the acrylic polymer may be, for example, 1% by weight or more, and 10% by weight or more is suitable, preferably 30 wt% or more, more preferably 50 wt% or more (e.g., more than 50 wt%), may be 70 wt% or more, may be 80 wt% or more, may be 85 wt% or more, may be 90 wt% or more. It may be at least 92% by weight, or at least 95% by weight. By increasing the proportion of biomass heptyl (meth)acrylate used, the effect of use can be effectively expressed while improving the biomass carbon ratio of the acrylic polymer. The technology disclosed herein can be preferably practiced in a mode using an acrylic polymer with a monomer composition containing only biomass heptyl (meth)acrylate as the C 5-18 linear alkyl (meth)acrylate. Therefore, the upper limit of the proportion of biomass heptyl (meth)acrylate in the total C 5-18 linear alkyl (meth)acrylate is 100% by weight. In some other embodiments, the proportion of biomass heptyl (meth)acrylate in total C 5-18 linear alkyl (meth)acrylates may be 95 wt% or less, may be 75 wt% or less, and may be 60 wt% or less. It may be less than or equal to 50 wt% (for example, less than 50 wt%), less than or equal to 30 wt%, less than or equal to 10 wt%, or less than or equal to 1 wt%.
　アクリル系ポリマーを形成するモノマー成分は、上述の鎖状アルキル（メタ）アクリレートに加えて、上記鎖状アルキル（メタ）アクリレートと共重合可能な他のモノマー（共重合性モノマー）を含んでいてもよい。共重合性モノマーは、１種を単独でまたは２種以上を組み合わせて用いることができる。上記共重合性モノマーは、アクリル系ポリマーに架橋点を導入したり、アクリル系ポリマーの凝集力を高めたりするために役立ち得る。共重合性モノマーは、バイオマス由来であってもよく、非バイオマス由来であってもよい。 The monomer component forming the acrylic polymer may contain other monomers (copolymerizable monomers) copolymerizable with the chain alkyl (meth)acrylate in addition to the chain alkyl (meth)acrylate. good. The copolymerizable monomers may be used singly or in combination of two or more. The above-mentioned copolymerizable monomer can be useful for introducing cross-linking points into the acrylic polymer and increasing the cohesive strength of the acrylic polymer. The copolymerizable monomer may be biomass-derived or non-biomass-derived.
　いくつかの好ましい態様において、共重合性モノマーとしてカルボキシ基含有モノマーが用いられる。アクリル系ポリマーに架橋点を導入するための共重合性モノマー成分としてカルボキシ基含有モノマーを、架橋剤（例えばエポキシ系架橋剤）と組み合わせて用いることにより、凝集力が向上し、再剥離可能な良好な接着力に調節しやすく、また経時での接着力上昇を抑制することができ、例えば再剥離される表面保護用途に適した粘着剤を形成しやすい。 In some preferred embodiments, a carboxy group-containing monomer is used as the copolymerizable monomer. By using a carboxy group-containing monomer as a copolymerizable monomer component for introducing a cross-linking point into an acrylic polymer in combination with a cross-linking agent (for example, an epoxy-based cross-linking agent), the cohesive force is improved and the removability is improved. It is easy to adjust the adhesive strength to a moderate level, and an increase in the adhesive strength over time can be suppressed.
　上記カルボキシ基含有モノマーとしては、例えば、アクリル酸、メタクリル酸、クロトン酸等の、エチレン性不飽和モノカルボン酸；イタコン酸、マレイン酸、フマル酸等の、エチレン性不飽和ジカルボン酸およびその無水物（無水マレイン酸、無水イコタン酸等）が挙げられる。なかでも、アクリル酸およびメタクリル酸が好ましく、アクリル酸がより好ましい。上記カルボキシ基含有モノマーは、１種を単独でまたは２種以上を組み合わせて用いることができる。 Examples of the carboxy group-containing monomers include ethylenically unsaturated monocarboxylic acids such as acrylic acid, methacrylic acid, and crotonic acid; ethylenically unsaturated dicarboxylic acids such as itaconic acid, maleic acid, and fumaric acid, and their anhydrides (maleic anhydride, isotanoic anhydride, etc.). Among them, acrylic acid and methacrylic acid are preferred, and acrylic acid is more preferred. The carboxy group-containing monomers may be used singly or in combination of two or more.
　アクリル系ポリマーを形成するモノマー成分における上記カルボキシ基含有モノマー（好適には（メタ）アクリル酸）の含有量は、例えば、モノマー成分全体の０．０１重量％以上であってもよく、０．１重量％以上であってもよく、０．５重量％超が適当であり、いくつかの好ましい態様では、１重量％以上（例えば１重量％超）であってもよく、２重量％以上でもよく、３重量％以上でもよい。また、モノマー成分全体に占める上記カルボキシ基含有モノマー（好適には（メタ）アクリル酸）の含有量は、例えば１５重量％未満であり、１０重量％以下とすることが適当であり、いくつかの好ましい態様では、８重量％以下であってもよく、６重量％以下でもよく、５重量％以下でもよい。上記カルボキシ基含有モノマー（好適には（メタ）アクリル酸）を上記の範囲で適当量使用することにより、凝集力が向上し、再剥離可能な良好な接着力に調節しやすく、例えば再剥離される表面保護用途に適した粘着剤を形成しやすい。 The content of the carboxy group-containing monomer (preferably (meth)acrylic acid) in the monomer component forming the acrylic polymer may be, for example, 0.01% by weight or more of the total monomer component, or 0.1 weight percent or more, suitably greater than 0.5 wt. , 3% by weight or more. In addition, the content of the carboxy group-containing monomer (preferably (meth)acrylic acid) in the entire monomer component is, for example, less than 15% by weight, and is suitably 10% by weight or less. In a preferred embodiment, it may be 8% by weight or less, 6% by weight or less, or 5% by weight or less. By using an appropriate amount of the carboxy group-containing monomer (preferably (meth)acrylic acid) within the above range, the cohesive force is improved, and it is easy to adjust to a good adhesive force that can be removed, for example, it can be removed again. It is easy to form a pressure-sensitive adhesive suitable for surface protection applications.
　アクリル系ポリマーを形成するモノマー成分は、他の共重合性モノマーを含んでいてもよい。他の共重合性モノマーは、上記鎖状アルキル（メタ）アクリレートおよび上記カルボキシ基含有モノマーとは異なるモノマーとして定義される。他の共重合性モノマーは、１種を単独でまたは２種以上を組み合わせて用いることができる。 The monomer component forming the acrylic polymer may contain other copolymerizable monomers. Other copolymerizable monomers are defined as monomers different from the chain alkyl (meth)acrylate and the carboxy group-containing monomer. Other copolymerizable monomers can be used singly or in combination of two or more.
　他の共重合性モノマーの非限定的な具体例としては、以下のものが挙げられる。
　水酸基含有モノマー：例えば、２－ヒドロキシエチル（メタ）アクリレート、２－ヒドロキシプロピル（メタ）アクリレート、３－ヒドロキシプロピル（メタ）アクリレート、２－ヒドロキシブチル（メタ）アクリレート、４－ヒドロキシブチル（メタ）アクリレート等の、ヒドロキシアルキル（メタ）アクリレート類；ビニルアルコール、アリルアルコール等の、不飽和アルコール類。
　スルホン酸基またはリン酸基を含有するモノマー：例えば、スチレンスルホン酸、アリルスルホン酸、ビニルスルホン酸ナトリウム、２－（メタ）アクリルアミド－２－メチルプロパンスルホン酸、（メタ）アクリルアミドプロパンスルホン酸、スルホプロピル（メタ）アクリレート、（メタ）アクリロイルオキシナフタレンスルホン酸、２－ヒドロキシエチルアクリロイルホスフェート等。
　エポキシ基含有モノマー：例えば、（メタ）アクリル酸グリシジルや（メタ）アクリル酸－２－エチルグリシジルエーテル等のエポキシ基含有アクリレート、アリルグリシジルエーテル、（メタ）アクリル酸グリシジルエーテル等。
　シアノ基含有モノマー：例えば、アクリロニトリル、メタクリロニトリル等。
　イソシアネート基含有モノマー：例えば、２－イソシアナートエチル（メタ）アクリレート等。
　アミド基含有モノマー：例えば、（メタ）アクリルアミド；Ｎ，Ｎ－ジメチル（メタ）アクリルアミド、Ｎ，Ｎ－ジエチル（メタ）アクリルアミド、Ｎ，Ｎ－ジプロピル（メタ）アクリルアミド、Ｎ，Ｎ－ジイソプロピル（メタ）アクリルアミド、Ｎ，Ｎ－ジ（ｎ－ブチル）（メタ）アクリルアミド、Ｎ，Ｎ－ジ（ｔ－ブチル）（メタ）アクリルアミド等の、Ｎ，Ｎ－ジアルキル（メタ）アクリルアミド；Ｎ－エチル（メタ）アクリルアミド、Ｎ－イソプロピル（メタ）アクリルアミド、Ｎ－ブチル（メタ）アクリルアミド、Ｎ－ｎ－ブチル（メタ）アクリルアミド等の、Ｎ－アルキル（メタ）アクリルアミド；Ｎ－ビニルアセトアミド等のＮ－ビニルカルボン酸アミド類；水酸基とアミド基とを有するモノマー、例えば、Ｎ－（２－ヒドロキシエチル）（メタ）アクリルアミド等のＮ－ヒドロキシアルキル（メタ）アクリルアミド；アルコキシ基とアミド基とを有するモノマー、例えば、Ｎ－メトキシメチル（メタ）アクリルアミド、Ｎ－メトキシエチル（メタ）アクリルアミド、Ｎ－ブトキシメチル（メタ）アクリルアミド等の、Ｎ－アルコキシアルキル（メタ）アクリルアミド；その他、Ｎ，Ｎ－ジメチルアミノプロピル（メタ）アクリルアミド、Ｎ－（メタ）アクリロイルモルホリン等。
　窒素原子含有環を有するモノマー：例えば、Ｎ－ビニル－２－ピロリドン、Ｎ－メチルビニルピロリドン、Ｎ－ビニルピリジン、Ｎ－ビニルピペリドン、Ｎ－ビニルピリミジン、Ｎ－ビニルピペラジン、Ｎ－ビニルピラジン、Ｎ－ビニルピロール、Ｎ－ビニルイミダゾール、Ｎ－ビニルオキサゾール、Ｎ－（メタ）アクリロイル－２－ピロリドン、Ｎ－（メタ）アクリロイルピペリジン、Ｎ－（メタ）アクリロイルピロリジン、Ｎ－ビニルモルホリン、Ｎ－ビニル－３－モルホリノン、Ｎ－ビニル－２－カプロラクタム、Ｎ－ビニル－１，３－オキサジン－２－オン、Ｎ－ビニル－３，５－モルホリンジオン、Ｎ－ビニルピラゾール、Ｎ－ビニルイソオキサゾール、Ｎ－ビニルチアゾール、Ｎ－ビニルイソチアゾール、Ｎ－ビニルピリダジン等（例えば、Ｎ－ビニル－２－カプロラクタム等のラクタム類）。
　スクシンイミド骨格を有するモノマー：例えば、Ｎ－（メタ）アクリロイルオキシメチレンスクシンイミド、Ｎ－（メタ）アクリロイル－６－オキシヘキサメチレンスクシンイミド、Ｎ－（メタ）アクリロイル－８－オキシヘキサメチレンスクシンイミド等。
　マレイミド類：例えば、Ｎ－シクロヘキシルマレイミド、Ｎ－イソプロピルマレイミド、Ｎ－ラウリルマレイミド、Ｎ－フェニルマレイミド等。
　イタコンイミド類：例えば、Ｎ－メチルイタコンイミド、Ｎ－エチルイタコンイミド、Ｎ－ブチルイタコンイミド、Ｎ－オクチルイタコンイミド、Ｎ－２－エチルへキシルイタコンイミド、Ｎ－シクロへキシルイタコンイミド、Ｎ－ラウリルイタコンイミド等。
　（メタ）アクリル酸アミノアルキル類：例えば、（メタ）アクリル酸アミノエチル、（メタ）アクリル酸Ｎ，Ｎ－ジメチルアミノエチル、（メタ）アクリル酸Ｎ，Ｎ－ジエチルアミノエチル、（メタ）アクリル酸ｔ－ブチルアミノエチル。
　アルコキシ基含有モノマー：例えば、（メタ）アクリル酸２－メトキシエチル、（メタ）アクリル酸３－メトキシプロピル、（メタ）アクリル酸２－エトキシエチル、（メタ）アクリル酸プロポキシエチル、（メタ）アクリル酸ブトキシエチル、（メタ）アクリル酸エトキシプロピル等の、（メタ）アクリル酸アルコキシアルキル類；（メタ）アクリル酸メトキシエチレングリコール、（メタ）アクリル酸メトキシポリプロピレングリコール等の、（メタ）アクリル酸アルコキシアルキレングリコール類。
　ビニルエステル類：例えば、酢酸ビニル、プロピオン酸ビニル等。
　ビニルエーテル類：例えば、例えば、メチルビニルエーテルやエチルビニルエーテル等のビニルアルキルエーテル。
　芳香族ビニル化合物：例えば、スチレン、α－メチルスチレン、ビニルトルエン等。
　オレフィン類：例えば、エチレン、ブタジエン、イソプレン、イソブチレン等。
　脂環式炭化水素基を有する（メタ）アクリレート：例えば、シクロペンチル（メタ）アクリレート、シクロヘキシル（メタ）アクリレート、イソボルニル（メタ）アクリレート、ジシクロペンタニル（メタ）アクリレート等。
　芳香族炭化水素基を有する（メタ）アクリレート：例えば、フェニル（メタ）アクリレート、フェノキシエチル（メタ）アクリレート、ベンジル（メタ）アクリレート等。
　その他、（メタ）アクリル酸テトラヒドロフルフリル等の複素環含有（メタ）アクリレート、塩化ビニルやフッ素原子含有（メタ）アクリレート等のハロゲン原子含有（メタ）アクリレート、シリコーン（メタ）アクリレート等のケイ素原子含有（メタ）アクリレート、テルペン化合物誘導体アルコールから得られる（メタ）アクリレート等。 Specific non-limiting examples of other copolymerizable monomers include the following.
Hydroxyl group-containing monomers: for example, 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 3-hydroxypropyl (meth)acrylate, 2-hydroxybutyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate hydroxyalkyl (meth)acrylates such as; unsaturated alcohols such as vinyl alcohol and allyl alcohol;
Monomers containing sulfonic or phosphoric acid groups: for example, styrenesulfonic acid, allylsulfonic acid, sodium vinylsulfonate, 2-(meth)acrylamido-2-methylpropanesulfonic acid, (meth)acrylamidopropanesulfonic acid, sulfo propyl (meth)acrylate, (meth)acryloyloxynaphthalenesulfonic acid, 2-hydroxyethyl acryloyl phosphate and the like.
Epoxy group-containing monomers: For example, epoxy group-containing acrylates such as glycidyl (meth)acrylate and 2-ethylglycidyl (meth)acrylate, allyl glycidyl ether, glycidyl ether (meth)acrylate, and the like.
Cyano group-containing monomers: for example acrylonitrile, methacrylonitrile and the like.
Isocyanate group-containing monomers: for example, 2-isocyanatoethyl (meth)acrylate and the like.
Amido group-containing monomers: for example, (meth)acrylamide; N,N-dimethyl(meth)acrylamide, N,N-diethyl(meth)acrylamide, N,N-dipropyl(meth)acrylamide, N,N-diisopropyl(meth) N,N-dialkyl(meth)acrylamides such as acrylamide, N,N-di(n-butyl)(meth)acrylamide, N,N-di(t-butyl)(meth)acrylamide; N-ethyl(meth) N-alkyl (meth)acrylamides such as acrylamide, N-isopropyl (meth)acrylamide, N-butyl (meth)acrylamide, Nn-butyl (meth)acrylamide; N-vinylcarboxylic acid amides such as N-vinylacetamide ; monomers having a hydroxyl group and an amide group, such as N-hydroxyalkyl (meth)acrylamides such as N-(2-hydroxyethyl)(meth)acrylamide; monomers having an alkoxy group and an amide group, such as N- N-alkoxyalkyl (meth)acrylamides such as methoxymethyl (meth)acrylamide, N-methoxyethyl (meth)acrylamide, N-butoxymethyl (meth)acrylamide; others, N,N-dimethylaminopropyl (meth)acrylamide, N-(meth)acryloylmorpholine and the like.
Monomers having a nitrogen atom-containing ring: for example, N-vinyl-2-pyrrolidone, N-methylvinylpyrrolidone, N-vinylpyridine, N-vinylpiperidone, N-vinylpyrimidine, N-vinylpiperazine, N-vinylpyrazine, N- Vinylpyrrole, N-vinylimidazole, N-vinyloxazole, N-(meth)acryloyl-2-pyrrolidone, N-(meth)acryloylpiperidine, N-(meth)acryloylpyrrolidine, N-vinylmorpholine, N-vinyl-3 -morpholinone, N-vinyl-2-caprolactam, N-vinyl-1,3-oxazin-2-one, N-vinyl-3,5-morpholinedione, N-vinylpyrazole, N-vinylisoxazole, N-vinyl thiazole, N-vinylisothiazole, N-vinylpyridazine and the like (for example, lactams such as N-vinyl-2-caprolactam);
Monomers having a succinimide skeleton: for example, N-(meth)acryloyloxymethylenesuccinimide, N-(meth)acryloyl-6-oxyhexamethylenesuccinimide, N-(meth)acryloyl-8-oxyhexamethylenesuccinimide and the like.
Maleimides: For example, N-cyclohexylmaleimide, N-isopropylmaleimide, N-laurylmaleimide, N-phenylmaleimide and the like.
Itaconimides: for example, N-methylitaconimide, N-ethylitaconimide, N-butylitaconimide, N-octylitaconimide, N-2-ethylhexylitaconimide, N-cyclohexylitaconimide, N-lauryl itaconimide and the like.
Aminoalkyl (meth)acrylates: for example, aminoethyl (meth)acrylate, N,N-dimethylaminoethyl (meth)acrylate, N,N-diethylaminoethyl (meth)acrylate, t (meth)acrylate - butylaminoethyl.
Alkoxy group-containing monomers: for example, 2-methoxyethyl (meth)acrylate, 3-methoxypropyl (meth)acrylate, 2-ethoxyethyl (meth)acrylate, propoxyethyl (meth)acrylate, (meth)acrylic acid Alkoxyalkyl (meth)acrylates such as butoxyethyl and ethoxypropyl (meth)acrylate; Alkoxyalkylene glycol (meth)acrylates such as methoxyethylene glycol (meth)acrylate and methoxypolypropylene glycol (meth)acrylate. kind.
Vinyl esters: For example, vinyl acetate, vinyl propionate and the like.
Vinyl ethers: For example, vinyl alkyl ethers such as methyl vinyl ether and ethyl vinyl ether.
Aromatic vinyl compounds: for example, styrene, α-methylstyrene, vinyltoluene and the like.
Olefins: For example, ethylene, butadiene, isoprene, isobutylene and the like.
(Meth)acrylates having an alicyclic hydrocarbon group: for example, cyclopentyl (meth)acrylate, cyclohexyl (meth)acrylate, isobornyl (meth)acrylate, dicyclopentanyl (meth)acrylate and the like.
(Meth)acrylates having an aromatic hydrocarbon group: for example, phenyl (meth)acrylate, phenoxyethyl (meth)acrylate, benzyl (meth)acrylate and the like.
In addition, heterocycle-containing (meth)acrylates such as tetrahydrofurfuryl (meth)acrylate, halogen atom-containing (meth)acrylates such as vinyl chloride and fluorine atom-containing (meth)acrylates, silicon atom-containing such as silicone (meth)acrylates (meth)acrylates, (meth)acrylates obtained from terpene compound derivative alcohols, and the like.
　アクリル系ポリマーを構成するモノマー成分は、上記他の共重合性モノマーを含んでもよく、含まなくてもよい。また、上記他の共重合性モノマーの量は、目的および用途に応じて適宜選択すればよく特に限定されない。上記モノマー成分における他の共重合性モノマーの含有量は、例えば５０重量％未満（例えば３０重量％未満）とすることが適切であり、１０重量％未満とすることが好ましく、５重量％未満がより好ましく、３重量％未満（例えば１重量％未満）としてもよい。ここに開示される技術は、モノマー成分が他の共重合性モノマーを実質的に含まない態様で好ましく実施され得る。 The monomer component that constitutes the acrylic polymer may or may not contain the other copolymerizable monomers. Moreover, the amount of the other copolymerizable monomer is not particularly limited, and may be appropriately selected according to the purpose and application. The content of other copolymerizable monomers in the monomer component is, for example, less than 50% by weight (for example, less than 30% by weight), preferably less than 10% by weight, and less than 5% by weight. More preferably, it may be less than 3% by weight (for example, less than 1% by weight). The technology disclosed herein can be preferably practiced in a mode in which the monomer component does not substantially contain other copolymerizable monomers.
　上記アクリル系ポリマーを構成するモノマー成分のバイオマス炭素比（アクリル系ポリマーのバイオマス炭素比）は、例えば１％以上であってもよく、１０％以上が適当であり、好ましくは３０％以上、より好ましくは５０％以上（例えば５０％超）であり、６０％以上でもよく、６５％以上でもよく、７０％以上でもよく、８０％以上でもよく、９０％～１００％でもよい。このように設計することにより、化石資源系材料への依存抑制に配慮したアクリル系粘着剤が得られる。 The biomass carbon ratio of the monomer component constituting the acrylic polymer (biomass carbon ratio of the acrylic polymer) may be, for example, 1% or more, suitably 10% or more, preferably 30% or more, more preferably 30% or more. is 50% or more (eg, more than 50%), may be 60% or more, may be 65% or more, may be 70% or more, may be 80% or more, or may be 90% to 100%. By designing in this way, an acrylic pressure-sensitive adhesive that takes into consideration the suppression of dependence on fossil resource-based materials can be obtained.
　アクリル系ポリマーを得る方法は特に限定されず、溶液重合法、エマルション重合法、バルク重合法、懸濁重合法、光重合法等の、アクリル系ポリマーの合成手法として知られている各種の重合方法を適宜採用することができる。例えば、溶液重合法を好ましく採用し得る。溶液重合法を採用する態様は、透明性や粘着性能等の観点から有利なものとなり得る。溶液重合を行う際のモノマー供給方法としては、全モノマー原料を一度に供給する一括仕込み方式、連続供給（滴下）方式、分割供給（滴下）方式等を適宜採用することができる。溶液重合を行う際の重合温度は、使用するモノマーおよび溶媒の種類、重合開始剤の種類等に応じて適宜選択することができ、例えば２０℃～１７０℃程度（典型的には４０℃～１４０℃程度）とすることができる。 The method for obtaining the acrylic polymer is not particularly limited, and various polymerization methods known as synthesis methods for acrylic polymers, such as solution polymerization, emulsion polymerization, bulk polymerization, suspension polymerization, and photopolymerization. can be adopted as appropriate. For example, a solution polymerization method can be preferably employed. An embodiment employing a solution polymerization method can be advantageous from the viewpoint of transparency, adhesion performance, and the like. As a method for supplying the monomers when carrying out solution polymerization, a batch charging method for supplying all monomer raw materials at once, a continuous supply (dropping) method, a divided supply (dropping) method, or the like can be appropriately employed. The polymerization temperature at the time of solution polymerization can be appropriately selected according to the type of monomer and solvent used, the type of polymerization initiator, etc. ° C.).
　溶液重合に用いる溶媒（重合溶媒）は、従来公知の有機溶媒（トルエン、酢酸エチル等）から適宜選択することができる。重合に用いる開始剤は、重合方法の種類に応じて、従来公知の重合開始剤（例えば２，２’－アゾビスイソブチロニトリル（ＡＩＢＮ）等のアゾ系重合開始剤や、過酸化物系開始剤等）から適宜選択することができる。重合開始剤の使用量は、通常の使用量であればよく、例えば、モノマー成分１００重量部に対して凡そ０．００５～１重量部程度（典型的には凡そ０．０１～１重量部程度）の範囲から選択することができる。 The solvent (polymerization solvent) used for solution polymerization can be appropriately selected from conventionally known organic solvents (toluene, ethyl acetate, etc.). Depending on the type of polymerization method, the initiator used for polymerization may be a conventionally known polymerization initiator (for example, an azo polymerization initiator such as 2,2'-azobisisobutyronitrile (AIBN) or a peroxide polymerization initiator). initiator, etc.). The amount of the polymerization initiator used may be a normal amount, for example, about 0.005 to 1 part by weight (typically about 0.01 to 1 part by weight) per 100 parts by weight of the monomer component. ).
　特に限定するものではないが、アクリル系ポリマーの重量平均分子量（Ｍｗ）は、通常、凡そ１０×１０４以上であることが適当である。かかるＭｗのアクリル系ポリマーによると、良好な凝集性を示す粘着剤が得られやすい。いくつかの態様において、アクリル系ポリマーのＭｗは、再剥離可能な接着力、凝集力等の観点から、例えば３０×１０４以上であることが適当であり、好ましくは５０×１０４以上であり、７０×１０４以上であってもよく、１００×１０４超でもよく、１１０×１０４以上でもよく、１２０×１０４以上でもよく、１３０×１０４以上でもよい。アクリル系ポリマーのＭｗを所定値以上とすることにより、粘着剤の凝集力が向上し、被着体表面への糊残りの発生を防止しやすい。また、被着体に対する密着性の観点から、アクリル系ポリマーのＭｗは、通常、凡そ５００×１０４以下であることが適当であり、３００×１０４以下であってもよく、１００×１０４以下（例えば１００×１０４未満）でもよい。Ｍｗを所定値以下とすることにより、粘着剤が適度な流動性を有し、被着体に対する濡れ性（密着性）が得られやすい傾向がある。良好な濡れ性を有することにより、例えば表面保護用途においては、表面保護フィルムが、使用中に被着体から剥がれず、その保護機能を好ましく全うすることができる。溶液重合法により得られたアクリル系ポリマーにおいては、そのＭｗが上述した好ましい範囲にあることが特に有意義である。 Although not particularly limited, the weight-average molecular weight (Mw) of the acrylic polymer is usually about 10×10 4 or more. An acrylic polymer having such an Mw tends to yield a pressure-sensitive adhesive exhibiting good cohesiveness. In some embodiments, the Mw of the acrylic polymer is, for example, 30×10 4 or more, preferably 50×10 4 or more, from the viewpoint of removable adhesive strength, cohesive strength, and the like. , 70×10 4 or more, more than 100×10 4 , 110×10 4 or more, 120×10 4 or more, or 130×10 4 or more. By setting the Mw of the acrylic polymer to a predetermined value or more, the cohesive force of the pressure-sensitive adhesive is improved, and it is easy to prevent the occurrence of adhesive residue on the surface of the adherend. Moreover, from the viewpoint of adhesion to the adherend, the Mw of the acrylic polymer is usually approximately 500×10 4 or less, may be 300×10 4 or less, or may be 100×10 4 . or less (for example, less than 100×10 4 ). By setting the Mw to a predetermined value or less, the pressure-sensitive adhesive tends to have appropriate fluidity and wettability (adhesion) to the adherend is likely to be obtained. By having good wettability, for example, in surface protection applications, the surface protection film does not peel off from the adherend during use, and can preferably fulfill its protective function. It is particularly significant that the Mw of the acrylic polymer obtained by the solution polymerization method is within the preferred range described above.
　アクリル系ポリマーのＭｗは、ゲルパーミエーションクロマトグラフィ（ＧＰＣ）により測定し、標準ポリスチレン換算の値として求めることができる。具体的には、ＧＰＣ測定装置として商品名「ＨＬＣ－８２２０ＧＰＣ」（東ソー社製）を用いて、下記の条件で測定して求めることができる。後述の実施例においても同様である。
　　［ＧＰＣの測定条件］
　サンプル濃度：０．１重量％（テトラヒドロフラン溶液）
　サンプル注入量：１０μＬ
　溶離液：テトラヒドロフラン（ＴＨＦ）
　流量（流速）：１．０ｍＬ／分
　カラム温度（測定温度）：４０℃
　カラム：
　　サンプルカラム：商品名「ＴＳＫｇｕａｒｄｃｏｌｕｍｎ　ＳｕｐｅｒＨＺ－Ｈ」１本＋商品名「ＴＳＫｇｅｌ　ＳｕｐｅｒＨＺＭ－Ｈ」２本」（東ソー社製）
　　リファレンスカラム：商品名「ＴＳＫｇｅｌ　ＳｕｐｅｒＨ－ＲＣ」１本（東ソー社製）
　検出器：示差屈折計（ＲＩ）
　標準試料：ポリスチレン The Mw of the acrylic polymer can be measured by gel permeation chromatography (GPC) and calculated as a value converted to standard polystyrene. Specifically, it can be obtained by measuring under the following conditions using a GPC measurement device with the trade name "HLC-8220GPC" (manufactured by Tosoh Corporation). The same applies to the examples described later.
[Measurement conditions of GPC]
Sample concentration: 0.1% by weight (tetrahydrofuran solution)
Sample injection volume: 10 μL
Eluent: Tetrahydrofuran (THF)
Flow rate (flow rate): 1.0 mL/min Column temperature (measurement temperature): 40°C
column:
Sample column: 1 product name “TSKguardcolumn SuperHZ-H” + 2 product name “TSKgel SuperHZM-H” (manufactured by Tosoh Corporation)
Reference column: Product name "TSKgel SuperH-RC" 1 column (manufactured by Tosoh Corporation)
Detector: differential refractometer (RI)
Standard sample: Polystyrene
　（架橋剤）
　ここに開示される粘着剤組成物は架橋剤を含む。架橋剤は、粘着剤の凝集力を高めるために役立ち得る。架橋剤は、粘着剤の分野において公知の各種架橋剤から選択することができる。かかる架橋剤の例としては、エポキシ系架橋剤、イソシアネート系架橋剤、オキサゾリン系架橋剤、アジリジン系架橋剤、メラミン系架橋剤、過酸化物系架橋剤、尿素系架橋剤、金属アルコキシド系架橋剤、金属キレート系架橋剤、金属塩系架橋剤、カルボジイミド系架橋剤、アミン系架橋剤等が挙げられる。架橋剤は、１種を単独でまたは２種以上を組み合わせて用いることができる。架橋剤は、バイオマス由来であってもよく、非バイオマス由来であってもよい。化石資源系材料への依存抑制に配慮したアクリル系粘着剤作製の観点から、バイオマス由来の架橋剤が好ましく使用される。ここに開示される技術は、粘着剤組成物に含まれるアクリル系ポリマーおよび架橋剤がともにバイオマス由来である態様で好ましく実施され得る。 (crosslinking agent)
The adhesive compositions disclosed herein contain a cross-linking agent. A cross-linking agent can serve to increase the cohesive strength of the adhesive. The cross-linking agent can be selected from various cross-linking agents known in the field of adhesives. Examples of such cross-linking agents include epoxy-based cross-linking agents, isocyanate-based cross-linking agents, oxazoline-based cross-linking agents, aziridine-based cross-linking agents, melamine-based cross-linking agents, peroxide-based cross-linking agents, urea-based cross-linking agents, and metal alkoxide-based cross-linking agents. , metal chelate cross-linking agents, metal salt cross-linking agents, carbodiimide cross-linking agents, amine cross-linking agents and the like. A crosslinking agent can be used individually by 1 type or in combination of 2 or more types. The cross-linking agent may be biomass-derived or non-biomass-derived. A cross-linking agent derived from biomass is preferably used from the viewpoint of production of an acrylic pressure-sensitive adhesive that takes into consideration the suppression of dependence on fossil resource-based materials. The technology disclosed herein can be preferably implemented in a mode in which both the acrylic polymer and the cross-linking agent contained in the pressure-sensitive adhesive composition are derived from biomass.
　架橋剤の使用量は特に限定されない。架橋剤の使用量は、アクリル系ポリマー１００重量部に対して、例えば０．１～２０重量部の範囲から選択し得る。凝集力の向上と被着体への密着性とをバランスよく両立する観点から、アクリル系ポリマー１００重量部に対する架橋剤の使用量は、通常、１５重量部以下とすることが好ましく、１０重量部以下でもよく、８重量部以下でもよく、７重量部以下でもよく、また、０．５重量部以上とすることが適当であり、１重量部以上でもよい。架橋剤の使用量を適当な範囲とすることにより、粘着剤の凝集力を高め、被着体への糊残り発生を防止することができ、また、被着体に対する密着性を得ることができる。 The amount of cross-linking agent used is not particularly limited. The amount of the cross-linking agent used can be selected, for example, from the range of 0.1 to 20 parts by weight with respect to 100 parts by weight of the acrylic polymer. From the viewpoint of achieving both improved cohesive strength and adhesion to the adherend in a well-balanced manner, the amount of the cross-linking agent used relative to 100 parts by weight of the acrylic polymer is usually preferably 15 parts by weight or less, preferably 10 parts by weight. 8 parts by weight or less, 7 parts by weight or less, 0.5 parts by weight or more is suitable, and 1 part by weight or more is also acceptable. By adjusting the amount of the cross-linking agent to be used in an appropriate range, it is possible to increase the cohesive force of the pressure-sensitive adhesive, prevent the occurrence of adhesive residue on the adherend, and obtain adhesion to the adherend. .
　いくつかの態様において、架橋剤は、少なくともエポキシ系架橋剤を含むことが好ましい。エポキシ系架橋剤は、１種を単独でまたは２種以上を組み合わせて用いることができる。エポキシ系架橋剤は、バイオマス由来であってもよく、非バイオマス由来であってもよい。化石資源系材料への依存抑制に配慮したアクリル系粘着剤作製の観点から、バイオマス由来のエポキシ系架橋剤が好ましく使用される。また、エポキシ系架橋剤は、他の架橋剤、例えばイソシアネート系架橋剤と組み合わせて用いてもよい。 In some embodiments, the cross-linking agent preferably contains at least an epoxy-based cross-linking agent. Epoxy-based cross-linking agents may be used singly or in combination of two or more. The epoxy-based cross-linking agent may be biomass-derived or non-biomass-derived. A biomass-derived epoxy-based cross-linking agent is preferably used from the viewpoint of production of an acrylic pressure-sensitive adhesive that takes into consideration the suppression of dependence on fossil resource-based materials. Also, the epoxy-based cross-linking agent may be used in combination with another cross-linking agent such as an isocyanate-based cross-linking agent.
　エポキシ系架橋剤としては、１分子中に２個以上のエポキシ基を有する化合物を特に制限なく用いることができる。１分子中に３～５個のエポキシ基を有するエポキシ系架橋剤が好ましい。エポキシ系架橋剤は、１種を単独でまたは２種以上を組み合わせて用いることができる。エポキシ系架橋剤の具体例として、例えばＮ，Ｎ，Ｎ’，Ｎ’－テトラグリシジル－ｍ－キシレンジアミン、１，３－ビス（Ｎ，Ｎ－ジグリシジルアミノメチル）シクロヘキサン、１，６－ヘキサンジオールジグリシジルエーテル、ポリエチレングリコールジグリシジルエーテル、ポリグリセロールポリグリシジルエーテル等が挙げられる。エポキシ系架橋剤の市販品としては、三菱ガス化学社製の商品名「ＴＥＴＲＡＤ－Ｃ」および商品名「ＴＥＴＲＡＤ－Ｘ」、ＤＩＣ社製の商品名「エピクロンＣＲ－５Ｌ」、ナガセケムテックス社製の商品名「デナコールＥＸ－５１２」、日産化学工業社製の商品名「ＴＥＰＩＣ－Ｇ」等が挙げられる。 As the epoxy-based cross-linking agent, a compound having two or more epoxy groups in one molecule can be used without particular limitation. An epoxy-based cross-linking agent having 3 to 5 epoxy groups in one molecule is preferred. Epoxy-based cross-linking agents may be used singly or in combination of two or more. Specific examples of epoxy-based cross-linking agents include N,N,N',N'-tetraglycidyl-m-xylenediamine, 1,3-bis(N,N-diglycidylaminomethyl)cyclohexane, and 1,6-hexane. Diol diglycidyl ether, polyethylene glycol diglycidyl ether, polyglycerol polyglycidyl ether and the like. Commercially available epoxy-based cross-linking agents include Mitsubishi Gas Chemical Company's trade name "TETRAD-C" and trade name "TETRAD-X", DIC's trade name "Epiclon CR-5L", and Nagase ChemteX Corporation. and "TEPIC-G" manufactured by Nissan Chemical Industries, Ltd. under the trade name of "Denacol EX-512".
　エポキシ系架橋剤の使用量は、アクリル系ポリマー１００重量部に対して、例えば凡そ０．１重量部以上であってよく、０．５重量部以上でもよく、１．０重量部以上でもよく、１．５重量部超でもよい。より高い使用効果を得る観点から、アクリル系ポリマー１００重量部に対するエポキシ系架橋剤の使用量は、例えば２．０重量部超であってよく、２．５重量部以上でもよく、３．０重量部以上でもよく、３．５重量部以上でもよい。また、アクリル系ポリマー１００重量部に対するエポキシ系架橋剤の使用量は、通常、２０重量部以下とすることが適当であり、１０重量部以下でもよく、８重量部以下でもよく、６重量部以下でもよく、５重量部以下（例えば５重量部未満）でもよい。エポキシ系架橋剤の使用量を適当な範囲とすることにより、粘着剤の凝集力を高め、再剥離可能な良好な接着力に調節しやすく、また経時での接着力上昇を抑制することができ、被着体への糊残り発生を防止することができ、また、被着体に対する密着性を得ることができる。また、エポキシ系架橋剤の使用量を制限することにより、透明な粘着剤を形成しやすい。 The amount of the epoxy-based cross-linking agent used may be, for example, approximately 0.1 parts by weight or more, 0.5 parts by weight or more, or 1.0 parts by weight or more, relative to 100 parts by weight of the acrylic polymer. It may be greater than 1.5 parts by weight. From the viewpoint of obtaining a higher use effect, the amount of the epoxy-based cross-linking agent used relative to 100 parts by weight of the acrylic polymer may be, for example, more than 2.0 parts by weight, may be 2.5 parts by weight or more, or may be 3.0 parts by weight. parts or more, or 3.5 parts by weight or more. In addition, the amount of the epoxy-based cross-linking agent to be used relative to 100 parts by weight of the acrylic polymer is usually appropriately 20 parts by weight or less, and may be 10 parts by weight or less, 8 parts by weight or less, or 6 parts by weight or less. 5 parts by weight or less (for example, less than 5 parts by weight) may be used. By adjusting the amount of the epoxy-based cross-linking agent to an appropriate range, it is possible to increase the cohesive strength of the pressure-sensitive adhesive, easily adjust the re-peelable adhesive strength, and suppress the increase in adhesive strength over time. In addition, it is possible to prevent the occurrence of adhesive residue on the adherend and to obtain good adhesion to the adherend. Also, by limiting the amount of the epoxy-based cross-linking agent used, it is easy to form a transparent pressure-sensitive adhesive.
　いくつかの態様において、経時における高速剥離の上昇を抑制する観点から、エポキシ系架橋剤の使用量は、アクリル系ポリマー１００重量部に対して、４重量部超であってもよく、４．５重量部以上でもよく、５重量部超でもよく、５．５重量部以上でもよい。 In some embodiments, from the viewpoint of suppressing an increase in high-speed peeling over time, the amount of the epoxy-based cross-linking agent used may be more than 4 parts by weight with respect to 100 parts by weight of the acrylic polymer, and may be 4.5 parts by weight. It may be greater than or equal to 5 parts by weight, or greater than 5.5 parts by weight.
　カルボキシ基含有モノマー（例えば（メタ）アクリル酸）とエポキシ系架橋剤を用いる場合において、カルボキシ基含有モノマーの使用量（２種以上のカルボキシ基含有モノマーを用いる場合はその合計量）ＷＡに対するエポキシ系架橋剤の使用量ＷＢの比（ＷＢ／ＷＡ）（重量基準）は、特に限定されないが、粘着剤の凝集力を高める観点から、０．７以上であることが好ましく、より好ましくは０．８以上であり、さらに好ましくは０．９以上（例えば１．０以上）であり、特に好ましくは１．１以上である。また、上記比（ＷＢ／ＷＡ）は、通常３．０以下であり、２．０以下でもよく、１．８以下でもよく、１．６以下でもよく、１．４以下でもよく、１．３以下でもよい。 When using a carboxy group-containing monomer (e.g., (meth)acrylic acid) and an epoxy-based cross-linking agent, the amount of the carboxy group-containing monomer used (the total amount when two or more carboxy group-containing monomers are used) epoxy system relative to WA The ratio (WB/WA) (weight basis) of the amount WB of the cross-linking agent used is not particularly limited, but from the viewpoint of increasing the cohesive strength of the adhesive, it is preferably 0.7 or more, more preferably 0.8. or more, more preferably 0.9 or more (for example, 1.0 or more), and particularly preferably 1.1 or more. The ratio (WB/WA) is usually 3.0 or less, 2.0 or less, 1.8 or less, 1.6 or less, 1.4 or less, or 1.3. It can be below.
　イソシアネート系架橋剤としては、１分子当たり２個以上のイソシアネート基を有するポリイソシアネート系架橋剤が好ましく用いられる。ポリイソシアネート系架橋剤１分子当たりのイソシアネート基の数は、好ましくは２～１０個であり、例えば２～４個であり、典型的には２または３個である。上記ポリイソシアネート系架橋剤としては、トリレンジイソシアネート、キシレンジイソシアネート等の芳香族ポリイソシアネート；イソホロンジイソシアネート等の脂環族イソシアネート；ヘキサメチレンジイソシアネート等の脂肪族ポリイソシアネート；が例示される。より具体的には、例えば、ブチレンジイソシアネート、ペンタメチレンジイソシアネート、ヘキサメチレンジイソシアネート等の低級脂肪族ポリイソシアネート類；シクロペンチレンジイソシアネート、シクロへキシレンジイソシアネート、イソホロンジイソシアネート等の脂環族ポリイソシアネート類；２，４－トリレンジイソシアネート、４，４’－ジフェニルメタンジイソシアネート、キシリレンジイソシアネート、ポリメチレンポリフェニルジイソシアネート等の芳香族ジイソシアネート類；トリメチロールプロパン／トリレンジイソシアネート３量体付加物（東ソー製、商品名「コロネートＬ」）、トリメチロールプロパン／ヘキサメチレンジイソシアネート３量体付加物（東ソー製、商品名「コロネートＨＬ」）、ヘキサメチレンジイソシアネートのイソシアヌレート体（東ソー製、商品名「コロネートＨＸ」）、ペンタメチレンジイソシアネートのイソシアヌレート体（三井化学社製、商品名「スタビオＤ－３７０Ｎ」）等のイソシアネート付加物；ポリエーテルポリイソシアネート、ポリエステルポリイソシアネート等のポリイソシアネート；これらポリイソシアネートとポリオールとの付加物；および、これらポリイソシアネートを、イソシアヌレート結合、ビューレット結合、アロファネート結合等により多官能化したポリイソシアネート；等が挙げられる。例えば、粘着剤に透明性が求められる用途では、ペンタメチレンジイソシアネート、ヘキサメチレンジイソシアネート等の脂肪族ジイソシアネート類や、かかる脂肪族ジイソシアネートのイソシアヌレート体等の使用が好ましい。 As the isocyanate-based cross-linking agent, a polyisocyanate-based cross-linking agent having two or more isocyanate groups per molecule is preferably used. The number of isocyanate groups per molecule of the polyisocyanate-based cross-linking agent is preferably 2-10, for example 2-4, typically 2 or 3. Examples of the polyisocyanate-based crosslinking agent include aromatic polyisocyanates such as tolylene diisocyanate and xylene diisocyanate; alicyclic isocyanates such as isophorone diisocyanate; and aliphatic polyisocyanates such as hexamethylene diisocyanate. More specifically, for example, lower aliphatic polyisocyanates such as butylene diisocyanate, pentamethylene diisocyanate and hexamethylene diisocyanate; alicyclic polyisocyanates such as cyclopentylene diisocyanate, cyclohexylene diisocyanate and isophorone diisocyanate; Aromatic diisocyanates such as 4-tolylene diisocyanate, 4,4'-diphenylmethane diisocyanate, xylylene diisocyanate, and polymethylene polyphenyl diisocyanate; L"), trimethylolpropane/hexamethylene diisocyanate trimer adduct (manufactured by Tosoh, trade name "Coronate HL"), isocyanurate form of hexamethylene diisocyanate (manufactured by Tosoh, trade name "Coronate HX"), pentamethylene diisocyanate isocyanurate (manufactured by Mitsui Chemicals, Inc., trade name "STABIO D-370N") and other isocyanate adducts; polyisocyanates such as polyether polyisocyanate and polyester polyisocyanate; adducts of these polyisocyanates and polyols; polyisocyanates obtained by polyfunctionalizing these polyisocyanates with isocyanurate bonds, biuret bonds, allophanate bonds, and the like; and the like. For example, in applications where the adhesive is required to have transparency, it is preferable to use aliphatic diisocyanates such as pentamethylene diisocyanate and hexamethylene diisocyanate, isocyanurates of such aliphatic diisocyanates, and the like.
　ここに開示される粘着剤組成物は、触媒を含んでもよい。触媒を使用することにより、粘着剤組成物の硬化反応（典型的には、上述の架橋剤の架橋反応）を効率よく進行させることができ、粘着シート作製後の早い段階から安定した接着を実現しやすい。触媒は架橋触媒ともいう。触媒としては、スズ（Ｓｎ）含有化合物（スズ系触媒）、ジルコニウム（Ｚｒ）含有化合物（ジルコニウム系触媒）、チタン（Ｔｉ）含有化合物（チタン系触媒）、鉄（Ｆｅ）含有化合物（鉄系触媒）、アルミニウム（Ａｌ）含有化合物（アルミニウム系触媒）、亜鉛（Ｚｎ）含有化合物（亜鉛系触媒）、ビスマス（Ｂｉ）含有化合物（ビスマス系触媒）等が挙げられる。これらは、典型的には、活性中心に金属を有する有機化合物であり、有機金属触媒ともいう。触媒は、１種を単独でまたは２種以上を組み合わせて用いることができる。ここに開示される技術は、触媒を含まない態様であっても、好適に実施され得る。 The adhesive composition disclosed here may contain a catalyst. By using a catalyst, the curing reaction of the pressure-sensitive adhesive composition (typically, the cross-linking reaction of the above-mentioned cross-linking agent) can proceed efficiently, and stable adhesion can be achieved from an early stage after the pressure-sensitive adhesive sheet is produced. It's easy to do. The catalyst is also called a cross-linking catalyst. Examples of catalysts include tin (Sn)-containing compounds (tin-based catalysts), zirconium (Zr)-containing compounds (zirconium-based catalysts), titanium (Ti)-containing compounds (titanium-based catalysts), iron (Fe)-containing compounds (iron-based catalysts). ), aluminum (Al)-containing compounds (aluminum-based catalysts), zinc (Zn)-containing compounds (zinc-based catalysts), bismuth (Bi)-containing compounds (bismuth-based catalysts), and the like. These are typically organic compounds having a metal in the active center and are also called organometallic catalysts. A catalyst can be used individually by 1 type or in combination of 2 or more types. The technology disclosed herein can be suitably practiced even in a mode that does not contain a catalyst.
　上記粘着剤組成物には、従来公知の各種添加剤を必要に応じて配合することができる。かかる添加剤の例としては、表面潤滑剤、レベリング剤、粘着付与樹脂、可塑剤、軟化剤、充填剤、着色剤（顔料、染料等）、帯電防止剤、酸化防止剤、防腐剤、光安定剤、紫外線吸収剤、重合禁止剤、シランカップリング剤等が挙げられる。これら任意成分としての添加剤の含有量は、使用目的に応じて適切に設定され得る。上記任意添加剤の使用量は、アクリル系ポリマー１００重量部に対して、例えば１０重量部未満であり、凡そ３重量部以下（例えば凡そ１重量部以下）とすることが適当である。 Various conventionally known additives can be blended into the adhesive composition as needed. Examples of such additives include surface lubricants, leveling agents, tackifying resins, plasticizers, softeners, fillers, colorants (pigments, dyes, etc.), antistatic agents, antioxidants, preservatives, light stabilizers. agents, ultraviolet absorbers, polymerization inhibitors, silane coupling agents, and the like. The content of these optional additives can be appropriately set according to the purpose of use. The amount of the optional additive used is, for example, less than 10 parts by weight, and is suitably about 3 parts by weight or less (for example, about 1 part by weight or less) with respect to 100 parts by weight of the acrylic polymer.
　（粘着剤組成物の形態）
　ここに開示される粘着剤組成物の形態は特に限定されず、水系粘着剤組成物、溶剤型粘着剤組成物等が好ましい。ここで、水系粘着剤組成物とは、水を主成分とする溶媒（水系溶媒）中に粘着剤（粘着剤層形成成分）を含む形態の粘着剤組成物のことをいい、粘着剤が水に分散した形態の水分散型粘着剤組成物や、粘着剤が水に溶解した形態の水溶性粘着剤組成物を包含する概念である。また、溶剤型粘着剤組成物とは、有機溶媒中に粘着剤を含む形態の粘着剤組成物のことをいう。溶剤型粘着剤組成物に含まれる有機溶媒としては、上述の溶液重合で用いられ得る有機溶媒（トルエンや酢酸エチル等）の１種または２種以上を特に制限なく用いることができる。ここに開示される技術は、粘着特性等の観点から、溶剤型粘着剤組成物から形成された粘着剤層を備える態様で好ましく実施され得る。溶剤型粘着剤組成物から形成された溶剤型粘着剤層を備える態様において、ここに開示される技術による効果は好ましく実現される。 (Form of adhesive composition)
The form of the pressure-sensitive adhesive composition disclosed herein is not particularly limited, and water-based pressure-sensitive adhesive compositions, solvent-based pressure-sensitive adhesive compositions, and the like are preferable. Here, the water-based pressure-sensitive adhesive composition refers to a pressure-sensitive adhesive composition in the form of containing a pressure-sensitive adhesive (pressure-sensitive adhesive layer-forming component) in a water-based solvent (water-based solvent). It is a concept that includes a water-dispersed pressure-sensitive adhesive composition in which the pressure-sensitive adhesive is dispersed in water and a water-soluble pressure-sensitive adhesive composition in which the pressure-sensitive adhesive is dissolved in water. Moreover, the solvent-type adhesive composition refers to an adhesive composition in the form of containing an adhesive in an organic solvent. As the organic solvent contained in the solvent-based pressure-sensitive adhesive composition, one or more organic solvents (toluene, ethyl acetate, etc.) that can be used in the above solution polymerization can be used without particular limitation. From the viewpoint of adhesive properties, the technology disclosed herein can be preferably practiced in a mode comprising a pressure-sensitive adhesive layer formed from a solvent-based pressure-sensitive adhesive composition. In an embodiment having a solvent-based pressure-sensitive adhesive layer formed from a solvent-based pressure-sensitive adhesive composition, the effects of the technique disclosed herein are preferably realized.
　（ゲル分率）
　ここに開示される粘着剤組成物は、乾燥後のゲル分率が７０％以上であることが好ましい。ゲル分率が７０％以上である粘着剤は、例えば製造時において、外力による打痕等の変形や損傷が生じにくく、外観の変化が生じにくい。そのような粘着剤は、平滑な表面を有する粘着シートとなりやすく、例えば透明粘着シートに形成して粘着シート越しの被着体検査をする場合に、高精度の検査が可能となり好ましい。また、ゲル分率を高く設定することにより、低速剥離における軽剥離性を示し、高速剥離における剥離力上昇が抑制され、かつ経時での接着力上昇が抑制され得る粘着剤を形成しやすい。そのような観点から、上記ゲル分率は、より好ましくは８０％超であり、８５％超（例えば９０％以上）であってもよい。上記ゲル分率は１００％であってもよいが、被着体に対する密着性の観点から、例えば９９％未満であってもよく、９５％未満（例えば９４％以下）でもよい。上記ゲル分率を測定するための粘着剤組成物の乾燥条件は１３０℃で３分間である。上記ゲル分率は、具体的には、後述の実施例に記載の方法で測定される。粘着剤組成物の乾燥後のゲル分率は、粘着剤（層）のゲル分率であり得るので、後述の粘着シートを構成する粘着剤（層）のゲル分率も、上記の範囲から設定され得る。 (Gel fraction)
The adhesive composition disclosed herein preferably has a gel fraction of 70% or more after drying. A pressure-sensitive adhesive having a gel fraction of 70% or more is less likely to cause deformation or damage such as dents due to external force during production, and less likely to cause changes in appearance. Such a pressure-sensitive adhesive tends to form a pressure-sensitive adhesive sheet having a smooth surface. For example, when a transparent pressure-sensitive adhesive sheet is formed and an adherend is inspected through the pressure-sensitive adhesive sheet, highly accurate inspection is possible, which is preferable. In addition, by setting the gel fraction high, it is easy to form a pressure-sensitive adhesive that exhibits light release properties in low-speed peeling, suppresses an increase in peel force in high-speed peeling, and can suppress an increase in adhesive strength over time. From such a viewpoint, the gel fraction is more preferably over 80%, and may be over 85% (for example, 90% or more). The gel fraction may be 100%, but may be, for example, less than 99% or less than 95% (for example, 94% or less) from the viewpoint of adhesion to the adherend. The drying conditions for the pressure-sensitive adhesive composition for measuring the gel fraction are 130° C. for 3 minutes. Specifically, the gel fraction is measured by the method described in Examples below. Since the gel fraction after drying of the adhesive composition can be the gel fraction of the adhesive (layer), the gel fraction of the adhesive (layer) constituting the adhesive sheet described later is also set from the above range. can be
　（バイオマス炭素比）
　いくつかの態様において、粘着剤組成物はバイオマス由来材料を含み、その不揮発分のバイオマス炭素比（粘着剤のバイオマス炭素比でもある。）が所定値以上であり得る。粘着剤組成物の不揮発分のバイオマス炭素比は、例えば１％以上であり、１０％以上であってもよく、好ましくは３０％以上、より好ましくは５０％以上である。粘着剤のバイオマス炭素比が高いことは、石油等に代表される化石資源系材料の使用量が少ないことを意味する。かかる観点において、粘着剤のバイオマス炭素比は高いほど好ましい。例えば、粘着剤組成物の不揮発分のバイオマス炭素比は、５５％以上であってよく、６０％以上であってもよく、６５％以上でもよく、７０％以上でもよく、７５％以上でもよく、８０％以上でもよく、８０％超でもよい。バイオマス炭素比の上限は、定義上１００％であり、９９％以下であってもよく、材料の入手容易性の観点から、９５％以下でもよく、９０％以下でもよい。良好な粘着性能を発揮しやすくする観点から、いくつかの態様において、粘着剤組成物の不揮発分のバイオマス炭素比は、例えば９０％以下であってよく、８５％以下でもよく、８０％以下でもよい。 (biomass carbon ratio)
In some embodiments, the pressure-sensitive adhesive composition contains a biomass-derived material, and the biomass-carbon ratio of the non-volatile matter (also the biomass-carbon ratio of the pressure-sensitive adhesive) can be a predetermined value or higher. The non-volatile biomass carbon ratio of the pressure-sensitive adhesive composition is, for example, 1% or more, may be 10% or more, preferably 30% or more, and more preferably 50% or more. A high biomass carbon ratio of the pressure-sensitive adhesive means that the amount of fossil resource-based materials such as petroleum used is small. From this point of view, the higher the biomass carbon ratio of the adhesive, the better. For example, the non-volatile biomass carbon ratio of the adhesive composition may be 55% or more, 60% or more, 65% or more, 70% or more, 75% or more, It may be 80% or more, or may be more than 80%. The upper limit of the biomass carbon ratio is 100% by definition, and may be 99% or less. From the viewpoint of availability of materials, it may be 95% or less or 90% or less. From the viewpoint of facilitating good adhesion performance, in some embodiments, the non-volatile biomass carbon ratio of the pressure-sensitive adhesive composition may be, for example, 90% or less, 85% or less, or 80% or less. good.
　＜粘着シート＞
　この明細書によると、ここに開示されるいずれかの粘着剤組成物から形成された粘着剤層を備える粘着シートが提供される。上記粘着シートは、非剥離性の基材（支持基材）の片面または両面に上記粘着剤層を有する形態の基材付き粘着シートであってもよく、上記粘着剤層が剥離ライナーに保持された形態等の基材レスの粘着シート（すなわち、非剥離性の基材を有しない粘着シート）であってもよい。ここに開示される粘着シートは、低速剥離における軽剥離性を有し、高速剥離における剥離力上昇が抑制されているので、剥離速度にかかわらず剥離がしやすい。また、経時での接着力上昇が抑制される傾向にある。したがって、使用後に再剥離される表面保護フィルムとして好適である。 <Adhesive sheet>
This specification provides a pressure-sensitive adhesive sheet comprising a pressure-sensitive adhesive layer formed from any of the pressure-sensitive adhesive compositions disclosed herein. The pressure-sensitive adhesive sheet may be a pressure-sensitive adhesive sheet with a substrate having the pressure-sensitive adhesive layer on one or both sides of a non-releasable substrate (supporting substrate), and the pressure-sensitive adhesive layer is held by a release liner. It may be a substrate-less pressure-sensitive adhesive sheet (that is, a pressure-sensitive adhesive sheet having no non-releasable substrate). The pressure-sensitive adhesive sheet disclosed herein has easy release properties in low-speed release and suppresses an increase in release force in high-speed release, so that it can be easily peeled regardless of the peel speed. In addition, there is a tendency that an increase in adhesive strength over time is suppressed. Therefore, it is suitable as a surface protection film that can be peeled again after use.
　一実施形態に係る粘着シートの構造を図１に模式的に示す。この粘着シート１は、第一面１０Ａおよび第二面１０Ｂを有するシート状の支持基材（例えば樹脂フィルム）１０と、その第一面１０Ａ側に設けられた粘着剤層２１とを備える基材付き片面粘着シートとして構成されている。粘着剤層２１は、支持基材１０の第一面１０Ａ側に固定的に、すなわち当該支持基材１０から粘着剤層２１を分離する意図なく、設けられている。このような片面接着性の粘着シート１は、その粘着面を被着体（保護対象、例えば偏光板等の光学部品）の表面に貼り付けて使用される表面保護フィルムとして好適である。使用前の粘着シート１は、図１に示すように、粘着剤層２１の表面（粘着面）２１Ａが、少なくとも粘着剤層２１に対向する側が剥離面となっている剥離ライナー３１によって保護された形態の剥離ライナー付き粘着シート１００の構成要素であり得る。あるいは、剥離ライナー３１を省略し、第二面１０Ｂが剥離面となっている支持基材１０を用い、粘着シート１を巻回することにより粘着面２１Ａが支持基材１０の第二面（背面）１０Ｂに当接して保護された形態（ロール形態）であってもよい。 The structure of an adhesive sheet according to one embodiment is schematically shown in FIG. The pressure-sensitive adhesive sheet 1 includes a sheet-like support base material (for example, a resin film) 10 having a first surface 10A and a second surface 10B, and a base material provided with an adhesive layer 21 provided on the first surface 10A side. It is configured as a single-sided adhesive sheet with The pressure-sensitive adhesive layer 21 is fixedly provided on the first surface 10A side of the supporting substrate 10 , that is, without the intention of separating the pressure-sensitive adhesive layer 21 from the supporting substrate 10 . Such a single-sided adhesive pressure-sensitive adhesive sheet 1 is suitable as a surface protection film that is used by attaching the pressure-sensitive adhesive surface to the surface of an adherend (object to be protected, for example, an optical component such as a polarizing plate). In the pressure-sensitive adhesive sheet 1 before use, as shown in FIG. 1, the surface (adhesive surface) 21A of the pressure-sensitive adhesive layer 21 is protected by a release liner 31 having a release surface on at least the side facing the pressure-sensitive adhesive layer 21. It can be a component of the pressure-sensitive adhesive sheet 100 with a release liner. Alternatively, by omitting the release liner 31 and using the supporting substrate 10 whose second surface 10B is the release surface, the adhesive sheet 1 is wound so that the adhesive surface 21A becomes the second surface (back surface) of the supporting substrate 10. ) 10B may be in a protected form (roll form).
　上述の剥離ライナー（剥離フィルムともいう。）としては、樹脂フィルムや紙等のライナー基材の表面に剥離層を有する剥離ライナーや、ポリオレフィン系樹脂（例えばポリエチレン、ポリプロピレン）やフッ素系樹脂等の低接着性材料からなる剥離ライナー等を用いることができる。上記剥離層は、例えば、シリコーン系、長鎖アルキル系、フッ素系、硫化モリブデン等の剥離処理剤により上記ライナー基材を表面処理して形成されたものであり得る。ライナー基材としては、後述する粘着シートの基材と同様、バイオマス由来の材料を用いて形成されたものや、リサイクル材料（リサイクルフィルム等）が好ましく用いられ得る。 Examples of the release liner (also referred to as a release film) include a release liner having a release layer on the surface of a liner substrate such as a resin film or paper, and a low-grade resin such as a polyolefin resin (e.g., polyethylene, polypropylene) or a fluororesin. A release liner or the like made of an adhesive material can be used. The release layer may be formed by surface-treating the liner base material with a release treatment agent such as a silicone-based, long-chain alkyl-based, fluorine-based, or molybdenum sulfide-based release agent. As the liner base material, a material formed using a biomass-derived material or a recycled material (recycled film, etc.) can be preferably used, similarly to the base material of the pressure-sensitive adhesive sheet described later.
　なお、ここでいう粘着シートの概念には、粘着テープ、粘着ラベル、粘着フィルム等と称されるものが包含され得る。粘着シートは、ロール形態であってもよく、枚葉状であってもよい。また、種々の形状に加工された形態の粘着シートであってもよい。 It should be noted that the concept of the adhesive sheet referred to here may include items called adhesive tapes, adhesive labels, adhesive films, and the like. The pressure-sensitive adhesive sheet may be in the form of a roll or sheet. Also, the pressure-sensitive adhesive sheet may be processed into various shapes.
　粘着剤組成物からの粘着剤（層）の形成は、従来公知の方法によって行うことができる。例えば、基材レスの両面粘着シートの場合は、剥離性を有する表面（剥離面）に粘着剤組成物を付与した後、該粘着剤組成物を硬化させることにより該表面上に粘着剤層（粘着剤からなる層）を形成することで粘着シートが形成され得る。また、基材付きの粘着シートの場合は、該基材に粘着剤組成物を直接付与（典型的には塗布）して硬化させることにより粘着剤層を形成する方法（直接法）を好ましく採用することができる。また、剥離性を有する表面（剥離面）に粘着剤組成物を付与して硬化させることにより該表面上に粘着剤層を形成し、その粘着剤層を基材に転写する方法（転写法）を採用してもよい。上記剥離面としては、剥離ライナーの表面や、剥離処理された基材背面等を利用し得る。また、上記粘着剤組成物の硬化は、該粘着剤組成物に乾燥、架橋、重合、冷却等の硬化処理を施すことにより行うことができる。二種以上の硬化処理を同時にまたは段階的に行ってもよい。 The formation of the adhesive (layer) from the adhesive composition can be performed by a conventionally known method. For example, in the case of a substrate-less double-sided PSA sheet, a PSA layer ( A pressure-sensitive adhesive sheet can be formed by forming a layer consisting of a pressure-sensitive adhesive. In the case of a pressure-sensitive adhesive sheet with a substrate, a method (direct method) of forming a pressure-sensitive adhesive layer by directly applying (typically applying) a pressure-sensitive adhesive composition to the substrate and curing the composition is preferably adopted. can do. Alternatively, a method of applying a pressure-sensitive adhesive composition to a surface having releasability (release surface) and curing the composition to form a pressure-sensitive adhesive layer on the surface and transferring the pressure-sensitive adhesive layer to a substrate (transfer method). may be adopted. As the release surface, the surface of a release liner, the back surface of a base material subjected to a release treatment, or the like can be used. Moreover, curing of the pressure-sensitive adhesive composition can be performed by subjecting the pressure-sensitive adhesive composition to a curing treatment such as drying, crosslinking, polymerization, or cooling. Two or more curing treatments may be performed simultaneously or stepwise.
　粘着剤組成物の塗布は、例えば、グラビアロールコーター、リバースロールコーター、キスロールコーター、ディップロールコーター、ダイコーター、バーコーター、ナイフコーター、スプレーコーター等の、公知ないし慣用のコーターを用いて行うことができる。あるいは、含浸やカーテンコート法等により粘着剤組成物を塗布してもよい。
　架橋反応の促進、製造効率向上等の観点から、粘着剤組成物の乾燥は加熱下で行うことが好ましい。乾燥温度は、例えば４０～１５０℃程度とすることができ、通常は６０～１３０℃程度とすることが好ましい。粘着剤組成物を乾燥させた後、さらに、粘着剤層内における成分移行の調整、架橋反応の進行、基材や粘着剤層内に存在し得る歪の緩和等を目的としてエージングを行ってもよい。 Application of the pressure-sensitive adhesive composition is carried out using known or commonly used coaters such as gravure roll coaters, reverse roll coaters, kiss roll coaters, dip roll coaters, die coaters, bar coaters, knife coaters, and spray coaters. can be done. Alternatively, the adhesive composition may be applied by impregnation, curtain coating, or the like.
From the viewpoint of promoting the cross-linking reaction, improving production efficiency, etc., it is preferable to dry the pressure-sensitive adhesive composition under heating. The drying temperature can be, for example, about 40 to 150°C, preferably about 60 to 130°C. After drying the pressure-sensitive adhesive composition, aging may be performed for the purpose of adjusting component migration in the pressure-sensitive adhesive layer, progressing the cross-linking reaction, relaxing distortion that may exist in the substrate or the pressure-sensitive adhesive layer, and the like. good.
　特に限定するものではないが、粘着剤層の厚さは、例えば凡そ１μｍ以上が適当であり、凡そ３μｍ以上（例えば凡そ５μｍ以上）が好ましい。被着体への接着性等の観点から、上記厚さは、好ましくは凡そ１０μｍ以上、より好ましくは凡そ１４μｍ以上、さらに好ましくは凡そ１７μｍ以上である。また、上記厚さは、例えば凡そ１００μｍ以下とすることができ、凡そ５０μｍ以下（例えば凡そ３０μｍ以下）が適当であり、好ましくは凡そ２５μｍ以下である。上記厚さを有する粘着剤層は、表面保護フィルム用途の粘着剤層として好適である。 Although not particularly limited, the thickness of the adhesive layer is, for example, approximately 1 μm or more, preferably approximately 3 μm or more (for example, approximately 5 μm or more). From the viewpoint of adhesion to adherends, etc., the thickness is preferably about 10 μm or more, more preferably about 14 μm or more, and even more preferably about 17 μm or more. The thickness can be, for example, approximately 100 μm or less, suitably approximately 50 μm or less (for example, approximately 30 μm or less), and preferably approximately 25 μm or less. A pressure-sensitive adhesive layer having the thickness described above is suitable as a pressure-sensitive adhesive layer for use as a surface protection film.
　（基材）
　ここに開示される粘着シートの支持体として用いられる支持基材の材料としては、特に限定されず、例えば樹脂フィルムを好ましく採用することができる。上記樹脂フィルムは、各種の樹脂材料をフィルム形状に成形したものであり得る。上記樹脂材料としては、透明性、機械的強度、熱安定性、水分遮蔽性、等方性等のうち、１または２以上の特性に優れた樹脂フィルムを構成し得るものが好ましい。例えば、ポリエチレンテレフタレート（ＰＥＴ）、ポリエチレンナフタレート（ＰＥＮ）、ポリブチレンテレフタレート等のポリエステル類；ジアセチルセルロース、トリアセチルセルロース等のセルロース類；ポリカーボネート類；ポリメチルメタクリレート等のアクリル系ポリマー類；等を主成分（すなわち、５０重量％よりも多く含まれる成分）とする樹脂材料から構成された樹脂フィルムを、上記基材として好ましく用いることができる。上記樹脂フィルムを構成する樹脂材料の他の例としては、ポリスチレン、アクリロニトリル－スチレン共重合体等のスチレン系ポリマー類；ポリオレフィン類、例えば、ポリエチレン、ポリプロピレン、環状ないしノルボルネン構造を有するポリオレフィン、エチレン－プロピレン共重合体等；ポリ塩化ビニル類；ナイロン６、ナイロン６，６、芳香族ポリアミド等のポリアミド類；等を主成分とするものが挙げられる。あるいは、ポリイミド類、ポリスルホン類、ポリエーテルスルホン類、ポリエーテルエーテルケトン類、ポリフェニレンスルフィド類、フッ素系樹脂、ポリビニルアルコール類、ポリ酢酸ビニル類、ポリ塩化ビニリデン類、ポリビニルブチラール類、ポリアリレート類、ポリオキシメチレン類、エポキシ樹脂類、等を主成分とする樹脂材料から構成された樹脂フィルムを基材に用いてもよい。上記樹脂フィルムを構成する樹脂材料は、これらの２種以上のブレンド物であり得る。 (Base material)
The material of the supporting substrate used as the support of the pressure-sensitive adhesive sheet disclosed herein is not particularly limited, and for example, a resin film can be preferably employed. The resin film may be formed by molding various resin materials into a film shape. As the resin material, those capable of forming a resin film excellent in one or more of properties such as transparency, mechanical strength, thermal stability, moisture shielding property, and isotropy are preferred. For example, polyesters such as polyethylene terephthalate (PET), polyethylene naphthalate (PEN), and polybutylene terephthalate; celluloses such as diacetyl cellulose and triacetyl cellulose; polycarbonates; acrylic polymers such as polymethyl methacrylate; A resin film composed of a resin material as a component (that is, a component contained in an amount of more than 50% by weight) can be preferably used as the substrate. Other examples of the resin material constituting the resin film include styrene-based polymers such as polystyrene and acrylonitrile-styrene copolymers; polyolefins such as polyethylene, polypropylene, polyolefins having a cyclic or norbornene structure, and ethylene-propylene. Polyvinyl chlorides; Polyamides such as nylon 6, nylon 6,6 and aromatic polyamides; Alternatively, polyimides, polysulfones, polyethersulfones, polyetheretherketones, polyphenylene sulfides, fluorine-based resins, polyvinyl alcohols, polyvinyl acetates, polyvinylidene chlorides, polyvinyl butyrals, polyarylates, poly A resin film composed of a resin material containing oxymethylenes, epoxy resins, or the like as a main component may be used as the substrate. The resin material constituting the resin film may be a blend of two or more of these.
　なお、本明細書において「樹脂フィルム」とは、非多孔質の構造であって、典型的には実質的に気泡を含まない（ボイドレスの）樹脂フィルムを意味する。したがって、上記樹脂フィルムは、発泡体フィルムや不織布、織布とは区別される概念である。 As used herein, the term "resin film" means a non-porous structure and typically substantially voidless resin film. Therefore, the resin film is a concept distinguished from foam films, nonwoven fabrics, and woven fabrics.
　基材の他の例としては、ポリウレタンフォーム、ポリエチレンフォーム、ポリクロロプレンフォーム等の発泡体からなる発泡体シートや、各種の繊維状物質（麻、綿等の天然繊維、ポリエステル、ビニロン等の合成繊維、アセテート等の半合成繊維等であり得る。）の単独または混紡等による織布および不織布；和紙、上質紙、クラフト紙、クレープ紙等の紙類、アルミニウム箔、銅箔等の金属箔、ガラス等が挙げられる。これらを複合した構成の基材であってもよい。このような複合構造の基材の例として、例えば、金属箔と上記プラスチックフィルムとが積層した構造の基材、ガラスクロス等の無機繊維で強化されたプラスチックシート等が挙げられる。 Other examples of base materials include foam sheets made of polyurethane foam, polyethylene foam, polychloroprene foam, etc., and various fibrous substances (natural fibers such as hemp and cotton, synthetic fibers such as polyester and vinylon). , Semi-synthetic fibers such as acetate, etc.) Woven and non-woven fabrics made by spinning alone or blended; etc. A base material having a structure in which these are combined may be used. Examples of such a substrate having a composite structure include a substrate having a structure in which a metal foil and the plastic film are laminated, and a plastic sheet reinforced with inorganic fibers such as glass cloth.
　基材は、バイオマス由来の材料から形成されたものであってもよく、非バイオマス由来の材料から形成されたものであってもよい。化石資源系材料への依存抑制に配慮した粘着シート作製の観点から、バイオマス由来の基材材料（典型的には樹脂フィルム）が好ましく使用される。 The base material may be formed from a biomass-derived material or may be formed from a non-biomass-derived material. A biomass-derived base material (typically a resin film) is preferably used from the viewpoint of pressure-sensitive adhesive sheet production that takes into account the suppression of dependence on fossil resource-based materials.
　また、基材は、リサイクル可能な材料やリサイクルされた材料（リサイクル材料ともいう。）を用いて形成されたものであってもよい。かかるリサイクル材料としては、樹脂フィルムが好ましく用いられる。樹脂フィルム（例えばＰＥＴフィルム等のポリエステルフィルム）はリサイクルが可能であるので、植物由来の材料を用いているか否かにかかわらず、使用後の樹脂フィルムを再利用することで、持続的な再生産が可能であり、環境負荷を低減することができる。このような、リサイクル可能な樹脂フィルムや、リサイクルされた樹脂フィルムは、リサイクルフィルムともいう。上記リサイクル材料（例えばリサイクルフィルム）は、バイオマス由来の材料から形成されたものであってもよく、非バイオマス由来の材料から形成されたものであってもよい。 In addition, the base material may be formed using recyclable materials or recycled materials (also referred to as recycled materials). A resin film is preferably used as such a recycled material. Since resin films (e.g., polyester films such as PET films) can be recycled, sustainable reproduction can be achieved by reusing used resin films regardless of whether plant-derived materials are used or not. is possible, and the environmental load can be reduced. Such recyclable resin films and recycled resin films are also called recycled films. The recycled material (for example, recycled film) may be formed from a biomass-derived material, or may be formed from a non-biomass-derived material.
　いくつかの好ましい態様では、上記基材として、ポリエステルを主成分（５０重量％よりも多く含まれる成分）とする樹脂（ポリエステル樹脂）がフィルム状に成形された樹脂フィルム（ポリエステル樹脂フィルム）を用いる。例えば、上記ポリエステルが主としてＰＥＴである樹脂フィルム（ＰＥＴフィルム）、主としてＰＥＮである樹脂フィルム（ＰＥＮフィルム）等を好ましく採用し得る。 In some preferred embodiments, a resin film (polyester resin film) in which a resin (polyester resin) containing polyester as a main component (a component containing more than 50% by weight) is molded into a film shape is used as the base material. . For example, a resin film (PET film) in which the polyester is mainly PET, a resin film (PEN film) in which the polyester is mainly PEN, or the like can be preferably employed.
　基材は単層構造であってもよく、多層構造を有するものであってもよい。したがって、基材として用いられ得る樹脂フィルムも、単層構造であってもよく、２層以上の多層構造（例えば３層構造）であってもよい。単層構造の樹脂フィルムを基材として好ましく使用し得る。 The base material may have a single-layer structure or a multilayer structure. Therefore, a resin film that can be used as a substrate may also have a single-layer structure or a multi-layer structure of two or more layers (for example, a three-layer structure). A resin film having a single-layer structure can be preferably used as the substrate.
　上記基材（典型的には樹脂フィルム）には、必要に応じて、酸化防止剤、紫外線吸収剤、帯電防止成分、可塑剤、着色剤（顔料、染料等）等の各種添加剤が配合されていてもよい。 Various additives such as antioxidants, ultraviolet absorbers, antistatic components, plasticizers, colorants (pigments, dyes, etc.) are blended with the base material (typically a resin film) as necessary. may be
　基材の粘着剤層側表面には、例えば、クロム酸処理、オゾン曝露、火炎曝露、高圧電撃曝露、イオン化放射線処理等の表面処理が施されていてもよい。このような表面処理は、例えば、基材と粘着剤層との密着性を高めるための処理であり得る。いくつかの態様では、基材の粘着剤層側表面には、プライマー処理が施されていてもよい。シリコーン系粘着剤との密着力の観点から、シリコーンプライマー処理が好ましい。いくつかの態様では、基材の背面はハードコート処理が施されたものであり得る。これにより、基材背面の耐スクラッチ性が向上し、粘着シートを保護シートとして用いる場合に、より優れた保護性能を発揮し得る。また、他のいくつかの態様では、基材は、静電気の発生を抑制する観点から、帯電防止処理が施されたものであり得る。基材はまた、防汚、指紋付着防止、防眩、反射防止等の各種処理が施されたものであり得る。 The adhesive layer side surface of the base material may be subjected to surface treatment such as chromic acid treatment, ozone exposure, flame exposure, high voltage shock exposure, and ionizing radiation treatment. Such a surface treatment may be, for example, a treatment for enhancing adhesion between the substrate and the pressure-sensitive adhesive layer. In some aspects, the surface of the substrate on the pressure-sensitive adhesive layer side may be subjected to a primer treatment. Silicone primer treatment is preferred from the viewpoint of adhesion to the silicone-based pressure-sensitive adhesive. In some aspects, the backside of the substrate can be hardcoated. As a result, the scratch resistance of the back surface of the base material is improved, and when the adhesive sheet is used as a protective sheet, more excellent protective performance can be exhibited. In some other embodiments, the base material may be subjected to antistatic treatment from the viewpoint of suppressing the generation of static electricity. The substrate may also be subjected to various treatments such as antifouling, anti-fingerprint, anti-glare, and anti-reflection treatments.
　基材の厚さは、粘着シートの用途、目的、使用形態等を考慮して適宜選択することができる。強度や取扱性等の作業性から、厚さ凡そ１０μｍ以上の基材が適当であり、その厚さは、好ましくは凡そ２０μｍ以上、より好ましくは凡そ３０μｍ以上（例えば３５μｍ以上）である。また、基材の厚さは、コスト等の観点から、凡そ２００μｍ以下が適当であり、好ましくは凡そ１５０μｍ以下、より好ましくは凡そ１００μｍ以下、さらに好ましくは凡そ７５μｍ以下（例えば５０μｍ以下）である。上記の厚さを有する基材は、例えば表面保護フィルムの基材として好適である。 The thickness of the base material can be appropriately selected in consideration of the application, purpose, usage pattern, etc. of the adhesive sheet. A base material having a thickness of about 10 μm or more is suitable from the standpoint of workability such as strength and handleability, and the thickness is preferably about 20 μm or more, more preferably about 30 μm or more (for example, 35 μm or more). Also, the thickness of the substrate is suitably about 200 μm or less, preferably about 150 μm or less, more preferably about 100 μm or less, even more preferably about 75 μm or less (for example, 50 μm or less) from the viewpoint of cost. A substrate having the thickness described above is suitable, for example, as a substrate for a surface protective film.
　（特性）
　＜初期接着力Ｆ０＞
　いくつかの好ましい態様において、エージングが十分に完了した粘着シート（好適には表面保護フィルム）は、引張速度３００ｍｍ／分で測定される初期低速接着力（Ｆ０Ｌｏｗ）が３．０Ｎ／２５ｍｍ以下であることが好ましい。ここで上記粘着シートのエージングは、例えば、粘着シートを５０℃環境下に３日間保管することによって行われ得る。この特性を満足する粘着シート（好適には表面保護フィルム）は、経時の接着力上昇が抑制されており、被着体（例えば保護対象物）から剥離する際の剥離力が低く抑制されているので、剥離がしやすい。剥離作業性の観点から、上記初期低速接着力（Ｆ０Ｌｏｗ）は、より好ましくは１．０Ｎ／２５ｍｍ以下（例えば０．２Ｎ／２５ｍｍ以下）であり、さらに好ましくは０．１４Ｎ／２５ｍｍ以下（例えば０．１４Ｎ／２５ｍｍ未満）、特に好ましくは０．１２Ｎ／２５ｍｍ以下（例えば０．１Ｎ／２５ｍｍ以下）である。被着体との密着性や被着体保護等の観点から、上記初期低速接着力（Ｆ０Ｌｏｗ）は、０．０１Ｎ／２５ｍｍ以上が適当であり、０．０３Ｎ／２５ｍｍ以上であってもよく、０．０５Ｎ／２５ｍｍ以上でもよい。上記初期低速接着力（Ｆ０Ｌｏｗ）は、具体的には、後述の実施例に記載の方法で測定される。 (Characteristic)
<Initial adhesive force F0>
In some preferred embodiments, the pressure-sensitive adhesive sheet (preferably surface protective film) that has been sufficiently aged has an initial low-speed adhesive strength (F0 Low ) measured at a tensile speed of 300 mm/min of 3.0 N/25 mm or less. Preferably. Here, the aging of the pressure-sensitive adhesive sheet can be performed, for example, by storing the pressure-sensitive adhesive sheet in an environment of 50° C. for 3 days. A pressure-sensitive adhesive sheet (preferably a surface protection film) that satisfies this property has a suppressed increase in adhesive strength over time, and a low peel strength when peeled from an adherend (for example, an object to be protected). Therefore, it is easy to peel off. From the viewpoint of peeling workability, the initial low-speed adhesive strength (F0 Low ) is more preferably 1.0 N/25 mm or less (e.g., 0.2 N/25 mm or less), still more preferably 0.14 N/25 mm or less (e.g., less than 0.14 N/25 mm), particularly preferably 0.12 N/25 mm or less (for example, 0.1 N/25 mm or less). From the viewpoint of adhesion to the adherend, protection of the adherend, etc., the initial low-speed adhesive strength (F0 Low ) is suitably 0.01 N/25 mm or more, and may be 0.03 N/25 mm or more. , 0.05 N/25 mm or more. Specifically, the initial low-speed adhesive strength (F0 Low ) is measured by the method described in Examples below.
　いくつかの好ましい態様において、エージングが十分に完了した粘着シート（好適には表面保護フィルム）は、引張速度３０ｍ／分で測定される初期高速接着力（Ｆ０Ｈｉｇｈ）が５．０Ｎ／２５ｍｍ以下であることが好ましい。ここで上記粘着シートのエージングは、例えば、粘着シートを５０℃環境下に３日間保管することによって行われ得る。この特性を満足する粘着シートは、比較的速い速度で被着体から剥離する際の剥離力が低く抑制されているので、剥離速度にかかわらず剥離性に優れる傾向がある。剥離作業性の観点から、上記初期高速接着力（Ｆ０Ｈｉｇｈ）は、より好ましくは３．０Ｎ／２５ｍｍ以下（例えば２．０Ｎ／２５ｍｍ以下）であり、さらに好ましくは１．５Ｎ／２５ｍｍ以下、特に好ましくは１．２Ｎ／２５ｍｍ以下（例えば１．０Ｎ／２５ｍｍ以下）である。被着体との密着性や被着体保護等の観点から、上記初期高速接着力（Ｆ０Ｈｉｇｈ）は、０．１Ｎ／２５ｍｍ以上が適当であり、０．３Ｎ／２５ｍｍ以上であってもよく、０．５Ｎ／２５ｍｍ以上でもよい。上記初期高速接着力（Ｆ０Ｈｉｇｈ）は、具体的には、後述の実施例に記載の方法で測定される。 In some preferred embodiments, the fully aged pressure-sensitive adhesive sheet (preferably surface protective film) has an initial high-speed adhesive strength (F0 High ) measured at a tensile speed of 30 m/min of 5.0 N/25 mm or less. Preferably. Here, the aging of the pressure-sensitive adhesive sheet can be performed, for example, by storing the pressure-sensitive adhesive sheet in an environment of 50° C. for 3 days. A pressure-sensitive adhesive sheet that satisfies these properties has a suppressed peel force when peeled from an adherend at a relatively high speed, and therefore tends to exhibit excellent peelability regardless of the peel speed. From the viewpoint of peeling workability, the initial high-speed adhesive strength (F0 High ) is more preferably 3.0 N/25 mm or less (for example, 2.0 N/25 mm or less), still more preferably 1.5 N/25 mm or less, especially It is preferably 1.2 N/25 mm or less (for example, 1.0 N/25 mm or less). From the viewpoint of adhesion to the adherend, protection of the adherend, etc., the initial high-speed adhesive strength (F0 High ) is suitably 0.1 N/25 mm or more, and may be 0.3 N/25 mm or more. , 0.5 N/25 mm or more. The initial high-speed adhesive strength (F0 High ) is specifically measured by the method described in Examples below.
　＜経時接着力Ｆ１＞
　いくつかの好ましい態様において、エージングが十分に完了した粘着シート（好適には表面保護フィルム）は、被着体に貼り合わせ、５０℃で７日間保管した後、引張速度３００ｍｍ／分で測定される経時低速接着力（Ｆ１Ｌｏｗ）が３．０Ｎ／２５ｍｍ以下であることが好ましい。ここで、上記粘着シートのエージングは、例えば、粘着シートを５０℃環境下に３日間保管することによって行われ得る。この特性を満足する粘着シート（好適には表面保護フィルム）は、経時の接着力上昇が抑制されており、被着体（例えば保護対象物）から剥離する際の剥離力が低く抑制されているので、剥離がしやすい。剥離作業性の観点から、上記経時低速接着力（Ｆ１Ｌｏｗ）は、より好ましくは１．０Ｎ／２５ｍｍ以下（例えば０．２Ｎ／２５ｍｍ以下）であり、さらに好ましくは０．１４Ｎ／２５ｍｍ以下（例えば０．１４Ｎ／２５ｍｍ未満）、特に好ましくは０．１２Ｎ／２５ｍｍ以下（例えば０．１Ｎ／２５ｍｍ以下）である。被着体との密着性や被着体保護等の観点から、上記経時低速接着力（Ｆ１Ｌｏｗ）は、０．０１Ｎ／２５ｍｍ以上が適当であり、０．０３Ｎ／２５ｍｍ以上であってもよく、０．０５Ｎ／２５ｍｍ以上でもよい。上記経時低速接着力（Ｆ１Ｌｏｗ）は、具体的には、後述の実施例に記載の方法で測定される。 <Adhesive strength over time F1>
In some preferred embodiments, the fully aged pressure-sensitive adhesive sheet (preferably surface protective film) is attached to the adherend, stored at 50 ° C. for 7 days, and then measured at a tensile speed of 300 mm / min. The low-speed adhesive strength (F1 Low ) over time is preferably 3.0 N/25 mm or less. Here, the aging of the pressure-sensitive adhesive sheet can be performed, for example, by storing the pressure-sensitive adhesive sheet in an environment of 50° C. for 3 days. A pressure-sensitive adhesive sheet (preferably a surface protection film) that satisfies this property has a suppressed increase in adhesive strength over time, and a low peel strength when peeled from an adherend (for example, an object to be protected). Therefore, it is easy to peel off. From the viewpoint of peeling workability, the low-speed adhesive strength over time (F1 Low ) is more preferably 1.0 N/25 mm or less (e.g., 0.2 N/25 mm or less), and still more preferably 0.14 N/25 mm or less (e.g., less than 0.14 N/25 mm), particularly preferably 0.12 N/25 mm or less (for example, 0.1 N/25 mm or less). From the viewpoint of adhesion to the adherend, protection of the adherend, etc., the low-speed adhesion over time (F1 Low ) is suitably 0.01 N/25 mm or more, and may be 0.03 N/25 mm or more. , 0.05 N/25 mm or more. The low-speed adhesion over time (F1 Low ) is specifically measured by the method described in Examples below.
　いくつかの好ましい態様において、エージングが十分に完了した粘着シート（好適には表面保護フィルム）は、被着体に貼り合わせ、５０℃で７日間保管した後、引張速度３０ｍ／分で測定される経時高速接着力（Ｆ１Ｈｉｇｈ）が５．０Ｎ／２５ｍｍ以下であることが好ましい。ここで、上記粘着シートのエージングは、例えば、粘着シートを５０℃環境下に３日間保管することによって行われ得る。この特性を満足する粘着シートは、比較的速い速度で被着体から剥離する際の剥離力が低く抑制されているので、剥離速度にかかわらず剥離性に優れる傾向がある。剥離作業性の観点から、上記経時高速接着力Ｆ１Ｈｉｇｈは、より好ましくは３．０Ｎ／２５ｍｍ以下（例えば２．０Ｎ／２５ｍｍ以下）であり、さらに好ましくは１．５Ｎ／２５ｍｍ以下、特に好ましくは１．２Ｎ／２５ｍｍ以下（例えば１．０Ｎ／２５ｍｍ以下）である。被着体との密着性や被着体保護等の観点から、上記経時高速接着力（Ｆ１Ｈｉｇｈ）は、０．１Ｎ／２５ｍｍ以上が適当であり、０．３Ｎ／２５ｍｍ以上であってもよく、０．５Ｎ／２５ｍｍ以上でもよい。上記経時高速接着力（Ｆ１Ｈｉｇｈ）は、具体的には、後述の実施例に記載の方法で測定される。 In some preferred embodiments, the fully aged pressure-sensitive adhesive sheet (preferably surface protective film) is attached to the adherend, stored at 50° C. for 7 days, and then measured at a tensile speed of 30 m / min. The high-speed adhesive strength (F1 High ) over time is preferably 5.0 N/25 mm or less. Here, the aging of the pressure-sensitive adhesive sheet can be performed, for example, by storing the pressure-sensitive adhesive sheet in an environment of 50° C. for 3 days. A pressure-sensitive adhesive sheet that satisfies these properties has a suppressed peel force when peeled from an adherend at a relatively high speed, and therefore tends to exhibit excellent peelability regardless of the peel speed. From the viewpoint of peeling workability, the high-speed adhesive force F1 High over time is more preferably 3.0 N/25 mm or less (for example, 2.0 N/25 mm or less), still more preferably 1.5 N/25 mm or less, and particularly preferably It is 1.2 N/25 mm or less (for example, 1.0 N/25 mm or less). From the viewpoint of adhesion to the adherend, protection of the adherend, etc., the high-speed adhesion over time (F1 High ) is suitably 0.1 N/25 mm or more, and may be 0.3 N/25 mm or more. , 0.5 N/25 mm or more. Specifically, the time-dependent high-speed adhesive strength (F1 High ) is measured by the method described in Examples below.
　いくつかの態様において、粘着シートは、全光線透過率が凡そ５０％以上の透明性を有することが好ましい。上記全光線透過率が８０％以上（例えば８５％以上）である透明粘着シートがより好ましい。上記全光線透過率の上限は、透明性が求められる用途において、９９％以下（例えば９５％以下）程度であってもよい。このような透明性を有する粘着シートは、例えば粘着シート越しの被着体検査をする場合に、高精度の検査が可能となり好ましい。かかる粘着シートは表面保護フィルムとして好適である。上記全光線透過率の値としては、ＪＩＳ　Ｋ　７３６１－１に準拠して測定された値を採用することができる。 In some aspects, the adhesive sheet preferably has transparency with a total light transmittance of about 50% or more. More preferably, the transparent pressure-sensitive adhesive sheet has a total light transmittance of 80% or more (for example, 85% or more). The upper limit of the total light transmittance may be about 99% or less (for example, 95% or less) in applications where transparency is required. Such a transparent pressure-sensitive adhesive sheet is preferable because it enables highly accurate inspection, for example, when an adherend is inspected through the pressure-sensitive adhesive sheet. Such an adhesive sheet is suitable as a surface protective film. As the value of the total light transmittance, a value measured according to JIS K 7361-1 can be adopted.
　＜用途＞
　ここに開示される粘着剤組成物から形成された粘着剤層を有する粘着シートは、種々の用途に利用され得る。ここに開示される粘着剤は、剥離速度によらずに軽剥離性であり、再剥離時の剥離作業性に優れるので、例えば、保護対象物に貼り付けられた後、その保護目的を達成すると、通常、保護対象物から剥離除去（再剥離）される表面保護フィルムとして好適である。上記表面保護フィルムの保護対象は特に限定されず、種々の製品、部品等に対して、保護フィルムとして用いられ得る。例えば、表面保護フィルムは、光学部品（例えば、偏光板、波長板等の液晶ディスプレイパネル構成要素として用いられる光学部品）の加工時や搬送時に該光学部品の表面を保護する表面保護フィルムとして特に好適である。より具体的には、表面保護フィルムは、液晶ディスプレイパネル、プラズマディスプレイパネル（ＰＤＰ）、有機エレクトロルミネッセンス（ＥＬ）ディスプレイ等の構成要素として用いられる光学部材の製造時、搬送時等に該光学部材を保護する用途に好適である。特に、液晶ディスプレイパネル用の偏光板（偏光フィルム、例えば反射型偏光フィルム）、波長板、位相差板、光学補償フィルム、輝度向上フィルム、光拡散シート、反射シート等の光学部品に適用される表面保護フィルムとして有用である。 <Application>
A pressure-sensitive adhesive sheet having a pressure-sensitive adhesive layer formed from the pressure-sensitive adhesive composition disclosed herein can be used for various purposes. The pressure-sensitive adhesive disclosed herein is easy to peel regardless of the peeling speed, and is excellent in peeling workability at the time of re-peeling. It is usually suitable as a surface protective film that is peeled off (removed) from an object to be protected. The object to be protected by the surface protective film is not particularly limited, and it can be used as a protective film for various products, parts, and the like. For example, the surface protective film is particularly suitable as a surface protective film for protecting the surface of optical parts (for example, optical parts used as liquid crystal display panel components such as polarizing plates and wavelength plates) during processing and transportation. is. More specifically, the surface protective film protects the optical member during the production, transportation, etc. of the optical member used as a component of liquid crystal display panels, plasma display panels (PDP), organic electroluminescence (EL) displays, and the like. Suitable for protective applications. In particular, surfaces applied to optical components such as polarizing plates (polarizing films, e.g., reflective polarizing films) for liquid crystal display panels, wavelength plates, retardation plates, optical compensation films, brightness enhancement films, light diffusion sheets, reflection sheets, etc. Useful as a protective film.
　また、ここに開示される粘着剤組成物は、いくつかの態様において、バイオマス炭素比の高いアクリル系ポリマーを含み得ることから、従来の一般的なアクリル系粘着剤（すなわち、バイオマス炭素比の低いアクリル系粘着剤）が使用されている各種の用途において該アクリル系粘着剤の代替として用いられることで、化石資源系材料の依存抑制に貢献することができる。ここに開示される粘着シートは、典型的には、化石資源系材料への依存度が低減された粘着シート（例えば表面保護フィルム）として好ましく利用され得る。 In addition, the pressure-sensitive adhesive composition disclosed herein, in some embodiments, can contain an acrylic polymer with a high biomass carbon ratio, so that a conventional general acrylic pressure-sensitive adhesive (i.e., a low biomass carbon ratio By being used as a substitute for acrylic pressure-sensitive adhesives in various applications where acrylic pressure-sensitive adhesives are used, it is possible to contribute to the suppression of dependence on fossil resource-based materials. The pressure-sensitive adhesive sheet disclosed herein can typically be preferably used as a pressure-sensitive adhesive sheet (for example, a surface protective film) with reduced dependence on fossil resource-based materials.
　以下、本発明に関するいくつかの実施例を説明するが、本発明をかかる実施例に示すものに限定することを意図したものではない。なお、以下の説明における「部」は、特に断りがない限り重量基準である。 Several examples of the present invention will be described below, but the present invention is not intended to be limited to those shown in the examples. "Parts" in the following description are by weight unless otherwise specified.
　＜試験例１＞
　＜アクリル系ポリマーの調製＞
　（調製例Ａ１）
　還流器、撹拌機、窒素ガス導入管および温度計を備えたフラスコに、モノマー成分としてのｎ－ヘプチルアクリレート（ＨｐＡ）９５部およびアクリル酸（ＡＡ）５部と、酢酸エチル（重合溶媒）を固形分濃度３０％になるように仕込み、さらに重合開始剤としてアゾビスイソブチロニトリル（ＡＩＢＮ）０．２部を投入し、緩やかに攪拌しながら窒素ガス導入し、フラスコ内の液温を６０℃付近に保って６時間重合反応を行い、その後７０℃で２時間熟成し、アクリル系ポリマー（Ａ１）の溶液を得た。得られたアクリル系ポリマー（Ａ１）の重量平均分子量（Ｍｗ）は７７万であった。なお、上記ＨｐＡは、バイオマス由来のヘプチルアルコールを用いて合成された、バイオマス由来のヘプチル基をエステル末端に有する化合物である。 <Test Example 1>
<Preparation of acrylic polymer>
(Preparation Example A1)
In a flask equipped with a reflux device, a stirrer, a nitrogen gas inlet tube and a thermometer, 95 parts of n-heptyl acrylate (HpA) and 5 parts of acrylic acid (AA) as monomer components and ethyl acetate (polymerization solvent) were added as solids. Further, 0.2 part of azobisisobutyronitrile (AIBN) was added as a polymerization initiator, nitrogen gas was introduced while gently stirring, and the liquid temperature in the flask was raised to 60°C. The polymerization reaction was carried out for 6 hours while maintaining the temperature in the vicinity, and then aged at 70° C. for 2 hours to obtain a solution of acrylic polymer (A1). The weight average molecular weight (Mw) of the obtained acrylic polymer (A1) was 770,000. The above HpA is a compound having a biomass-derived heptyl group at the ester end, synthesized using biomass-derived heptyl alcohol.
　（調製例Ａ２）
　還流器、撹拌機、窒素ガス導入管および温度計を備えたフラスコに、モノマー成分としてのｎ－ヘプチルアクリレート（ＨｐＡ）９５部およびアクリル酸（ＡＡ）５部と、酢酸エチル（重合溶媒）を固形分濃度４０％になるように仕込み、さらに重合開始剤としてＡＩＢＮ０．２部を投入し、緩やかに攪拌しながら窒素ガス導入し、フラスコ内の液温を６０℃付近に保って６時間重合反応を行い、その後７０℃で２時間熟成し、アクリル系ポリマー（Ａ２）の溶液を得た。得られたアクリル系ポリマー（Ａ２）のＭｗは１３７万であった。なお、上記ＨｐＡは、バイオマス由来のヘプチルアルコールを用いて合成された、バイオマス由来のヘプチル基をエステル末端に有する化合物である。 (Preparation Example A2)
In a flask equipped with a reflux device, a stirrer, a nitrogen gas inlet tube and a thermometer, 95 parts of n-heptyl acrylate (HpA) and 5 parts of acrylic acid (AA) as monomer components and ethyl acetate (polymerization solvent) were added as solids. Further, 0.2 parts of AIBN was added as a polymerization initiator, nitrogen gas was introduced while gently stirring, and the liquid temperature in the flask was maintained at around 60°C, and the polymerization reaction was allowed to proceed for 6 hours. and then aged at 70° C. for 2 hours to obtain a solution of acrylic polymer (A2). Mw of the obtained acrylic polymer (A2) was 1,370,000. The above HpA is a compound having a biomass-derived heptyl group at the ester end, synthesized using biomass-derived heptyl alcohol.
　（調製例Ａ３）
　還流器、撹拌機、窒素ガス導入管および温度計を備えたフラスコに、モノマー成分としてのｎ－ブチルアクリレート（ＢＡ）９５部およびアクリル酸（ＡＡ）５部と、酢酸エチル（重合溶媒）を固形分濃度３０％になるように仕込み、さらに重合開始剤としてＡＩＢＮ０．２部を投入し、緩やかに攪拌しながら窒素ガス導入し、フラスコ内の液温を６０℃付近に保って６時間重合反応を行い、その後７０℃で２時間熟成し、アクリル系ポリマー（Ａ３）の溶液を得た。得られたアクリル系ポリマー（Ａ３）のＭｗは８２万であった。 (Preparation Example A3)
In a flask equipped with a reflux device, a stirrer, a nitrogen gas inlet tube and a thermometer, 95 parts of n-butyl acrylate (BA) and 5 parts of acrylic acid (AA) as monomer components and ethyl acetate (polymerization solvent) were added as solids. Further, 0.2 parts of AIBN was added as a polymerization initiator, nitrogen gas was introduced while gently stirring, and the liquid temperature in the flask was maintained at around 60°C, and the polymerization reaction was allowed to proceed for 6 hours. and then aged at 70° C. for 2 hours to obtain a solution of acrylic polymer (A3). Mw of the obtained acrylic polymer (A3) was 820,000.
　（調製例Ａ４）
　還流器、撹拌機、窒素ガス導入管および温度計を備えたフラスコに、モノマー成分としての２－エチルヘキシルアクリレート（２ＥＨＡ）９５部およびアクリル酸（ＡＡ）５部と、酢酸エチル（重合溶媒）を固形分濃度４０％になるように仕込み、さらに重合開始剤としてＡＩＢＮ０．２部を投入し、緩やかに攪拌しながら窒素ガス導入し、フラスコ内の液温を６０℃付近に保って６時間重合反応を行い、その後７０℃で２時間熟成し、アクリル系ポリマー（Ａ４）の溶液を得た。得られたアクリル系ポリマー（Ａ４）のＭｗは７７万であった。 (Preparation Example A4)
95 parts of 2-ethylhexyl acrylate (2EHA) and 5 parts of acrylic acid (AA) as monomer components and ethyl acetate (polymerization solvent) were added to a flask equipped with a reflux device, a stirrer, a nitrogen gas inlet tube and a thermometer. Further, 0.2 parts of AIBN was added as a polymerization initiator, nitrogen gas was introduced while gently stirring, and the liquid temperature in the flask was maintained at around 60°C, and the polymerization reaction was allowed to proceed for 6 hours. and then aged at 70° C. for 2 hours to obtain a solution of acrylic polymer (A4). Mw of the obtained acrylic polymer (A4) was 770,000.
　＜実施例１＞
　（粘着剤組成物の調製）
　調製例Ａ１で得たアクリル系ポリマー（Ａ１）の溶液を、酢酸エチルで固形分濃度２２％になるまで希釈し、この溶液に、当該溶液の固形分１００部に対しエポキシ系架橋剤（Ｂ１）（三菱ガス化学株式会社製、商品名「テトラッドＣ」）６部（固形分）を加えて撹伴を行い、本例に係るアクリル系粘着剤組成物を得た。 <Example 1>
(Preparation of adhesive composition)
The solution of the acrylic polymer (A1) obtained in Preparation Example A1 was diluted with ethyl acetate to a solid content concentration of 22%, and the solution was added with an epoxy cross-linking agent (B1) per 100 parts of the solid content of the solution. (manufactured by Mitsubishi Gas Chemical Co., Ltd., trade name "Tetrad C") 6 parts (solid content) was added and stirred to obtain an acrylic pressure-sensitive adhesive composition according to this example.
　（粘着シートの作製）
　ポリエチレンテレフタレート（ＰＥＴ）フィルム（厚さ３８μｍ）上に、上記配合直後のアクリル粘着剤組成物を塗布し、１３０℃で３分間乾燥することより溶剤を除去して粘着剤層（厚さ２１μｍ）を形成した。その後、粘着剤層表面を剥離フィルムで覆い、５０℃の温度環境下で３日間エージングさせて、本例に係る粘着シートを得た。 (Preparation of adhesive sheet)
The acrylic pressure-sensitive adhesive composition immediately after the above formulation was applied onto a polyethylene terephthalate (PET) film (thickness 38 μm) and dried at 130° C. for 3 minutes to remove the solvent and form a pressure-sensitive adhesive layer (thickness 21 μm). formed. After that, the surface of the adhesive layer was covered with a release film and aged in a temperature environment of 50° C. for 3 days to obtain an adhesive sheet according to this example.
　＜実施例２＞
　使用するアクリル系ポリマーを、調製例Ａ２で得たアクリル系ポリマー（Ａ２）に変更した以外は実施例１と同様の方法で粘着剤組成物を調製し、この粘着剤組成物を用いて、実施例１と同様の方法で本例に係る粘着シートを得た。 <Example 2>
A pressure-sensitive adhesive composition was prepared in the same manner as in Example 1 except that the acrylic polymer used was changed to the acrylic polymer (A2) obtained in Preparation Example A2. A pressure-sensitive adhesive sheet according to this example was obtained in the same manner as in Example 1.
　＜比較例１＞
　使用するアクリル系ポリマーを、調製例Ａ３で得たアクリル系ポリマー（Ａ３）に変更した以外は実施例１と同様の方法で粘着剤組成物を調製し、この粘着剤組成物を用いて、実施例１と同様の方法で本例に係る粘着シートを得た。 <Comparative Example 1>
A pressure-sensitive adhesive composition was prepared in the same manner as in Example 1 except that the acrylic polymer used was changed to the acrylic polymer (A3) obtained in Preparation Example A3, and this pressure-sensitive adhesive composition was used. A pressure-sensitive adhesive sheet according to this example was obtained in the same manner as in Example 1.
　＜比較例２＞
　使用するアクリル系ポリマーを、調製例Ａ４で得たアクリル系ポリマー（Ａ４）に変更した以外は実施例１と同様の方法で粘着剤組成物を調製し、この粘着剤組成物を用いて、実施例１と同様の方法で本例に係る粘着シートを得た。 <Comparative Example 2>
A pressure-sensitive adhesive composition was prepared in the same manner as in Example 1 except that the acrylic polymer used was changed to the acrylic polymer (A4) obtained in Preparation Example A4, and this pressure-sensitive adhesive composition was used. A pressure-sensitive adhesive sheet according to this example was obtained in the same manner as in Example 1.
　＜評価＞
　（粘着剤ゲル分率）
　剥離処理が施されたＰＥＴフィルム（厚さ３８μｍ）に、配合直後の粘着剤組成物溶液を塗布し、１３０℃で３分間乾燥することより溶剤を除去して粘着剤層（厚さ２１μｍ）を形成した。形成した粘着剤層からＷ１ｇ分を取り出し、多孔質ＰＴＦＥ（ポリテトラフルオロエチレン）シートに包んでサンプルとした。サンプルをガラス瓶に入れ、酢酸エチル溶液に浸して７日間静置した後、サンプルを取り出して１３０℃で２時間乾燥させた。乾燥後のサンプルを秤量して、そこから多孔質ＰＴＦＥシートの重量を引き、粘着剤の乾燥後の重さＷ２ｇを求めた。Ｗ１およびＷ２を次式に代入し、ゲル分率［％］を算出した。
　ゲル分率［％］=（Ｗ２／Ｗ１）×１００
　多孔質ＰＴＦＥシートとしては、日東電工社製の商品名「ＴＥＭＩＳＨ」またはその相当品を使用することができる。 <Evaluation>
(Adhesive gel fraction)
The adhesive composition solution immediately after blending was applied to a peel-treated PET film (38 μm thick) and dried at 130° C. for 3 minutes to remove the solvent and form an adhesive layer (21 μm thick). formed. A portion of W 1 g was taken out from the formed pressure-sensitive adhesive layer and wrapped in a porous PTFE (polytetrafluoroethylene) sheet to obtain a sample. A sample was placed in a glass bottle, immersed in an ethyl acetate solution, and allowed to stand for 7 days, after which the sample was taken out and dried at 130° C. for 2 hours. The sample after drying was weighed, and the weight of the porous PTFE sheet was subtracted from it to obtain the post-drying weight W2g of the adhesive. W1 and W2 were substituted into the following formula to calculate the gel fraction [%].
Gel fraction [%] = (W2/W1) x 100
As the porous PTFE sheet, trade name "TEMISH" manufactured by Nitto Denko Corporation or its equivalent can be used.
　（対ガラス初期接着力Ｆ０）
　粘着シートを複数用意し、幅２５ｍｍ、長さ８０ｍｍのサイズにカットし、エタノールを染み込ませたクリーンウェスで１０往復擦って洗浄した清浄なソーダガラス板に、２ｋｇのローラーを転がして一往復する方法で圧着して接着力評価用サンプルとした。上記評価用サンプルを室温下に３０分放置後、高速剥離試験機を用いて、剥離角度１８０°、引張速度３００ｍ／分の条件と、剥離角度１８０°、引張速度３０ｍ／分の各条件で接着力［Ｎ／２５ｍｍ］を測定した。被着体のガラス板としては、松浪硝子社製のソーダガラス板（品番「Ｓ２００４２３」）またはその相当品が用いられる。また、高速剥離試験機としては、協和界面科学株式会社製の商品名「ＶＰＡ－Ｈ２００」またはその相当品が用いられる。 (Initial adhesive strength to glass F0)
Prepare multiple adhesive sheets, cut them into 25 mm width and 80 mm length sizes, rub them 10 times with a clean cloth impregnated with ethanol, and wash them with a clean soda glass plate. to obtain a sample for adhesive strength evaluation. After leaving the evaluation sample at room temperature for 30 minutes, a high-speed peel tester was used to bond under the conditions of a peel angle of 180° and a tensile speed of 300 m/min, and under the conditions of a peel angle of 180° and a tensile speed of 30 m/min. The force [N/25mm] was measured. As the glass plate of the adherend, a soda glass plate (product number “S200423”) manufactured by Matsunami Glass Co., Ltd. or an equivalent thereof is used. As the high-speed peeling tester, a trade name "VPA-H200" manufactured by Kyowa Interface Science Co., Ltd. or its equivalent is used.
　（対ガラス経時接着力Ｆ１）
　粘着シートを複数用意し、幅２５ｍｍ、長さ８０ｍｍのサイズにカットし、エタノールを染み込ませたクリーンウェスで１０往復擦って洗浄した清浄なソーダガラス板に、２ｋｇのローラーを転がして一往復する方法で圧着して接着力評価用サンプルとした。上記評価用サンプルを５０℃環境下に７日間放置した。７日後、サンプルを取り出し、室温（２３℃）下で１時間静置した後に、高速剥離試験機を用いて、剥離角度１８０°、引張速度３００ｍ／分の条件と、剥離角度１８０°、引張速度３０ｍ／分の各条件で接着力［Ｎ／２５ｍｍ］を測定した。被着体のガラス板としては、松浪硝子社製のソーダガラス板（品番「Ｓ２００４２３」）またはその相当品が用いられる。また、高速剥離試験機としては、協和界面科学株式会社製の商品名「ＶＰＡ－Ｈ２００」またはその相当品が用いられる。 (Adhesive force to glass over time F1)
Prepare multiple adhesive sheets, cut them into 25 mm width and 80 mm length sizes, rub them 10 times with a clean cloth impregnated with ethanol, and wash them with a clean soda glass plate. to obtain a sample for adhesive strength evaluation. The evaluation sample was left in an environment of 50° C. for 7 days. After 7 days, the sample was taken out and allowed to stand at room temperature (23° C.) for 1 hour. Adhesion [N/25 mm] was measured under each condition of 30 m/min. As the glass plate of the adherend, a soda glass plate (product number “S200423”) manufactured by Matsunami Glass Co., Ltd. or an equivalent thereof is used. As the high-speed peeling tester, a trade name "VPA-H200" manufactured by Kyowa Interface Science Co., Ltd. or its equivalent is used.
　各例の概要と評価結果を表１に示す。 Table 1 shows an overview and evaluation results of each example.
Figure JPOXMLDOC01-appb-T000001
Figure JPOXMLDOC01-appb-T000001
　表１に示されるように、Ｃ５－１８直鎖アルキル（メタ）アクリレートをモノマー成分として含むアクリル系ポリマーと、架橋剤と、を含む粘着剤組成物を用いた実施例１および２では、ｎ－ブチルアクリレートを使用した比較例１および２－エチルヘキシルアクリレートを使用した比較例２と比較し、初期の接着力について、低速剥離した場合の接着力が低く、さらに高速剥離した場合も接着力上昇が抑制される傾向が認められた。また、Ｃ５－１８直鎖アルキル（メタ）アクリレートをモノマー成分として含むアクリル系ポリマーと、架橋剤と、を含む粘着剤組成物を用いた実施例１および２では、初期接着力Ｆ０と経時接着力Ｆ１との差が小さく、経時での接着力上昇が抑制されることが確認された。 As shown in Table 1, in Examples 1 and 2 using a pressure-sensitive adhesive composition containing an acrylic polymer containing a C 5-18 linear alkyl (meth)acrylate as a monomer component and a cross-linking agent, n -Compared with Comparative Example 1 using butyl acrylate and Comparative Example 2 using 2-ethylhexyl acrylate, the initial adhesive strength was low when peeled at low speed, and the adhesive strength increased even when peeled at high speed. A tendency to be suppressed was observed. Further, in Examples 1 and 2 using a pressure-sensitive adhesive composition containing an acrylic polymer containing a C 5-18 linear alkyl (meth)acrylate as a monomer component and a cross-linking agent, the initial adhesive strength F0 and the adhesion over time It was confirmed that the difference from the force F1 was small, and the increase in the adhesive force over time was suppressed.
　＜試験例２＞
　　＜アクリル系ポリマーの調製＞
　（調製例Ａ５）
　還流器、撹拌機、窒素ガス導入管および温度計を備えたフラスコに、モノマー成分としてのｎ－ヘプチルアクリレート（ＨｐＡ）９５部およびアクリル酸（ＡＡ）５部と、酢酸エチル（重合溶媒）を固形分濃度３０％になるように仕込み、さらに重合開始剤としてアゾビスイソブチロニトリル（ＡＩＢＮ）０．３部を投入し、緩やかに攪拌しながら窒素ガス導入し、フラスコ内の液温を６０℃付近に保って２時間重合反応を行い、その後７０℃で６時間熟成し、アクリル系ポリマー（Ａ５）の溶液を得た。得られたアクリル系ポリマー（Ａ５）の重量平均分子量（Ｍｗ）は５５万であった。なお、上記ＨｐＡは、バイオマス由来のヘプチルアルコールを用いて合成された、バイオマス由来のヘプチル基をエステル末端に有する化合物である。 <Test Example 2>
<Preparation of acrylic polymer>
(Preparation Example A5)
In a flask equipped with a reflux device, a stirrer, a nitrogen gas inlet tube and a thermometer, 95 parts of n-heptyl acrylate (HpA) and 5 parts of acrylic acid (AA) as monomer components and ethyl acetate (polymerization solvent) were added as solids. Further, 0.3 part of azobisisobutyronitrile (AIBN) was added as a polymerization initiator, nitrogen gas was introduced while gently stirring, and the liquid temperature in the flask was brought to 60°C. The polymerization reaction was carried out for 2 hours while maintaining the temperature in the vicinity, and then aged at 70° C. for 6 hours to obtain a solution of acrylic polymer (A5). The weight average molecular weight (Mw) of the obtained acrylic polymer (A5) was 550,000. The above HpA is a compound having a biomass-derived heptyl group at the ester end, synthesized using biomass-derived heptyl alcohol.
　＜実施例３＞
　（粘着剤組成物の調製）
　調製例Ａ５で得たアクリル系ポリマー（Ａ５）の溶液を、酢酸エチルで固形分濃度２２％になるまで希釈し、この溶液に、当該溶液の固形分１００部に対しエポキシ系架橋剤（Ｂ１）（三菱ガス化学株式会社製、商品名「テトラッドＣ」）６部（固形分）を加えて撹伴を行い、本例に係るアクリル系粘着剤組成物を得た。 <Example 3>
(Preparation of adhesive composition)
The solution of the acrylic polymer (A5) obtained in Preparation Example A5 was diluted with ethyl acetate to a solid content concentration of 22%, and the solution was added with an epoxy cross-linking agent (B1) per 100 parts of the solid content of the solution. (manufactured by Mitsubishi Gas Chemical Co., Ltd., trade name "Tetrad C") 6 parts (solid content) was added and stirred to obtain an acrylic pressure-sensitive adhesive composition according to this example.
　（粘着シートの作製）
　ポリエチレンテレフタレート（ＰＥＴ）フィルム（厚さ３８μｍ）上に、上記配合直後のアクリル粘着剤組成物を塗布し、１３０℃で３分間乾燥することより溶剤を除去して粘着剤層（厚さ２１μｍ）を形成した。その後、粘着剤層表面を剥離フィルムで覆い、５０℃の温度環境下で３日間エージングさせて、本例に係る粘着シートを得た。 (Preparation of adhesive sheet)
The acrylic pressure-sensitive adhesive composition immediately after the above formulation was applied onto a polyethylene terephthalate (PET) film (thickness 38 μm) and dried at 130° C. for 3 minutes to remove the solvent and form a pressure-sensitive adhesive layer (thickness 21 μm). formed. After that, the surface of the adhesive layer was covered with a release film and aged in a temperature environment of 50° C. for 3 days to obtain an adhesive sheet according to this example.
　＜実施例４＞
　（粘着剤組成物の調製）
　調製例Ａ５で得たアクリル系ポリマー（Ａ５）の溶液を、酢酸エチルで固形分濃度２２％になるまで希釈し、この溶液に、当該溶液の固形分１００部に対しエポキシ系架橋剤（Ｂ１）（三菱ガス化学株式会社製、商品名「テトラッドＣ」）５部（固形分）を加えて撹伴を行い、本例に係るアクリル系粘着剤組成物を得た。
　（粘着シートの作製）
　実施例３に係るアクリル系粘着剤組成物の代わりに、本例に係るアクリル系粘着剤組成物を用いること以外は実施例３と同様の方法で本例に係る粘着シートを得た。 <Example 4>
(Preparation of adhesive composition)
The solution of the acrylic polymer (A5) obtained in Preparation Example A5 was diluted with ethyl acetate to a solid content concentration of 22%, and the solution was added with an epoxy cross-linking agent (B1) per 100 parts of the solid content of the solution. (manufactured by Mitsubishi Gas Chemical Company, Inc., trade name "Tetrad C") 5 parts (solid content) was added and stirred to obtain an acrylic pressure-sensitive adhesive composition according to this example.
(Preparation of adhesive sheet)
A pressure-sensitive adhesive sheet according to this example was obtained in the same manner as in Example 3, except that the acrylic pressure-sensitive adhesive composition according to this example was used instead of the acrylic pressure-sensitive adhesive composition according to Example 3.
　＜実施例５＞
　（粘着剤組成物の調製）
　調製例Ａ５で得たアクリル系ポリマー（Ａ５）の溶液を、酢酸エチルで固形分濃度２２％になるまで希釈し、この溶液に、当該溶液の固形分１００部に対しエポキシ系架橋剤（Ｂ１）（三菱ガス化学株式会社製、商品名「テトラッドＣ」）４部（固形分）を加えて撹伴を行い、本例に係るアクリル系粘着剤組成物を得た。
　（粘着シートの作製）
　実施例３に係るアクリル系粘着剤組成物の代わりに、本例に係るアクリル系粘着剤組成物を用いること以外は実施例３と同様の方法で本例に係る粘着シートを得た。 <Example 5>
(Preparation of adhesive composition)
The solution of the acrylic polymer (A5) obtained in Preparation Example A5 was diluted with ethyl acetate to a solid content concentration of 22%, and the solution was added with an epoxy cross-linking agent (B1) per 100 parts of the solid content of the solution. (Mitsubishi Gas Chemical Co., Ltd., trade name "Tetrad C") 4 parts (solid content) was added and stirred to obtain an acrylic pressure-sensitive adhesive composition according to this example.
(Preparation of adhesive sheet)
A pressure-sensitive adhesive sheet according to this example was obtained in the same manner as in Example 3, except that the acrylic pressure-sensitive adhesive composition according to this example was used instead of the acrylic pressure-sensitive adhesive composition according to Example 3.
　＜実施例６＞
　調製例Ａ５で得たアクリル系ポリマー（Ａ５）の溶液を、酢酸エチルで固形分濃度２２％になるまで希釈し、この溶液に、当該溶液の固形分１００部に対しエポキシ系架橋剤（Ｂ１）（三菱ガス化学株式会社製、商品名「テトラッドＣ」）６部（固形分）を加えて撹伴を行い、本例に係るアクリル系粘着剤組成物を得た。 <Example 6>
The solution of the acrylic polymer (A5) obtained in Preparation Example A5 was diluted with ethyl acetate to a solid content concentration of 22%, and the solution was added with an epoxy cross-linking agent (B1) per 100 parts of the solid content of the solution. (manufactured by Mitsubishi Gas Chemical Co., Ltd., trade name "Tetrad C") 6 parts (solid content) was added and stirred to obtain an acrylic pressure-sensitive adhesive composition according to this example.
　（粘着シートの作製）
　ポリエチレンテレフタレート（ＰＥＴ）フィルム（厚さ３８μｍ）上に、上記配合直後のアクリル粘着剤組成物を塗布し、１３０℃で３分間乾燥することより溶剤を除去して粘着剤層（厚さ５μｍ）を形成した。その後、粘着剤層表面を剥離フィルムで覆い、５０℃の温度環境下で３日間エージングさせて、本例に係る粘着シートを得た。 (Preparation of adhesive sheet)
The acrylic pressure-sensitive adhesive composition immediately after the above formulation was applied onto a polyethylene terephthalate (PET) film (thickness 38 μm) and dried at 130° C. for 3 minutes to remove the solvent and form a pressure-sensitive adhesive layer (thickness 5 μm). formed. After that, the surface of the adhesive layer was covered with a release film and aged in a temperature environment of 50° C. for 3 days to obtain an adhesive sheet according to this example.
　＜評価＞
　試験例１と同様の方法を用いて、実施例３～６の粘着剤ゲル分率、対ガラス初期接着力Ｆ０および対ガラス経時接着力Ｆ１を測定した。各例の概要と評価結果を表２に示す。 <Evaluation>
Using the same method as in Test Example 1, the adhesive gel fraction, initial adhesive force to glass F0 and adhesive force to glass over time F1 of Examples 3 to 6 were measured. Table 2 shows the outline and evaluation results of each example.
Figure JPOXMLDOC01-appb-T000002
Figure JPOXMLDOC01-appb-T000002
　表１および表２に示されるように、Ｃ５－１８直鎖アルキル（メタ）アクリレートをモノマー成分として含むアクリル系ポリマーと、架橋剤と、を含む粘着剤組成物を用いた実施例３～６についても、ｎ－ブチルアクリレートを使用した比較例１および２－エチルヘキシルアクリレートを使用した比較例２と比較し、初期の接着力について、低速剥離した場合の接着力が低く、さらに高速剥離した場合も接着力上昇が抑制される傾向が認められた。実施例１～３の結果の対比から、アクリル系ポリマーの分子量（Ｍｗ）の違いにより、経時による高速剥離の接着力変化の傾向に差が見られた。また、実施例３～５の結果の対比により、架橋剤の量を低下させることによって高速剥離による経時接着力が上昇する傾向にあることが確認された。さらに、実施例６の結果より、粘着剤層の厚さを５μｍとしても、本発明の効果が見られることが確認された。 As shown in Tables 1 and 2, Examples 3 to 6 using a pressure-sensitive adhesive composition containing an acrylic polymer containing C 5-18 linear alkyl (meth)acrylate as a monomer component and a cross-linking agent Also, compared to Comparative Example 1 using n-butyl acrylate and Comparative Example 2 using 2-ethylhexyl acrylate, the initial adhesive strength was low when peeled at low speed, and even when peeled at high speed A tendency to suppress the increase in adhesive strength was observed. From the comparison of the results of Examples 1 to 3, it was found that the difference in the molecular weight (Mw) of the acrylic polymer caused a difference in the tendency of the adhesive strength to change over time for high-speed peeling. Further, by comparing the results of Examples 3 to 5, it was confirmed that the adhesive strength over time due to high-speed peeling tends to increase by reducing the amount of the cross-linking agent. Furthermore, from the results of Example 6, it was confirmed that the effect of the present invention was observed even when the thickness of the pressure-sensitive adhesive layer was 5 µm.
　以上、本発明の具体例を詳細に説明したが、これらは例示にすぎず、請求の範囲を限定するものではない。請求の範囲に記載の技術には、以上に例示した具体例を様々に変形、変更したものが含まれる。 Specific examples of the present invention have been described in detail above, but these are merely examples and do not limit the scope of the claims. The technology described in the claims includes various modifications and changes of the specific examples illustrated above.
　　１　　粘着シート
　１０　　支持基材
　１０Ａ　第一面
　１０Ｂ　第二面（背面）
　２１　　粘着剤層
　２１Ａ　粘着面
　３１　　剥離ライナー
１００　　剥離ライナー付き粘着シート Reference Signs List 1 adhesive sheet 10 support substrate 10A first surface 10B second surface (back surface)
21 adhesive layer 21A adhesive surface 31 release liner 100 adhesive sheet with release liner

Claims (10)

  1. 　アクリル系ポリマーと、エポキシ系架橋剤と、を含む粘着剤組成物であって、
    　前記アクリル系ポリマーは、炭素数５～１８の直鎖アルキル基をエステル末端に有するアルキル（メタ）アクリレートを含むモノマー成分の重合物である、粘着剤組成物。     A pressure-sensitive adhesive composition containing an acrylic polymer and an epoxy cross-linking agent,
    The pressure-sensitive adhesive composition, wherein the acrylic polymer is a polymer of a monomer component containing an alkyl (meth)acrylate having a linear alkyl group having 5 to 18 carbon atoms at the ester end.
  2. 　前記モノマー成分は、さらに（メタ）アクリル酸を含む、請求項１に記載の粘着剤組成物。 The pressure-sensitive adhesive composition according to claim 1, wherein the monomer component further contains (meth)acrylic acid.
  3. 　前記炭素数５～１８の直鎖アルキル基をエステル末端に有するアルキル（メタ）アクリレートは、ｎ－へプチルアクリレートを含む、請求項１または２に記載の粘着剤組成物。 The pressure-sensitive adhesive composition according to claim 1 or 2, wherein the alkyl (meth)acrylate having a linear alkyl group having 5 to 18 carbon atoms at the ester end includes n-heptyl acrylate.
  4. 　請求項１～３のいずれか一項に記載の粘着剤組成物から形成された粘着剤。 A pressure-sensitive adhesive formed from the pressure-sensitive adhesive composition according to any one of claims 1 to 3.
  5. 　請求項４に記載の粘着剤からなる粘着剤層を有する粘着シート。 A pressure-sensitive adhesive sheet having a pressure-sensitive adhesive layer made of the pressure-sensitive adhesive according to claim 4.
  6. 　ゲル分率が７０％以上である粘着剤層を有する粘着シートであって、
    　前記粘着剤層は、アクリル系ポリマーと、架橋剤と、を含む粘着剤組成物から形成されており、
    　前記アクリル系ポリマーは、炭素数５～１８の直鎖アルキル基をエステル末端に有するアルキル（メタ）アクリレートを含むモノマー成分の重合物である、粘着シート。     A pressure-sensitive adhesive sheet having a pressure-sensitive adhesive layer with a gel fraction of 70% or more,
    The pressure-sensitive adhesive layer is formed from a pressure-sensitive adhesive composition containing an acrylic polymer and a cross-linking agent,
    The pressure-sensitive adhesive sheet, wherein the acrylic polymer is a polymer of a monomer component containing an alkyl (meth)acrylate having a linear alkyl group having 5 to 18 carbon atoms at the ester end.
  7. 　前記架橋剤は、エポキシ系架橋剤を含む、請求項６に記載の粘着シート。 The pressure-sensitive adhesive sheet according to claim 6, wherein the cross-linking agent includes an epoxy-based cross-linking agent.
  8. 　前記モノマー成分は、さらに（メタ）アクリル酸を含む、請求項６または７に記載の粘着シート。 The adhesive sheet according to claim 6 or 7, wherein the monomer component further contains (meth)acrylic acid.
  9. 　請求項５～８のいずれか一項に記載の粘着シートからなる表面保護フィルム。 A surface protection film made of the adhesive sheet according to any one of claims 5 to 8.
  10. 　５０℃環境下で３日間エージングした後に引張速度３０ｍ／分で測定される初期高速接着力が３．０Ｎ／２５ｍｍ以下である、請求項９に記載の表面保護フィルム。 The surface protective film according to claim 9, which has an initial high-speed adhesive strength of 3.0 N/25 mm or less measured at a tensile speed of 30 m/min after aging for 3 days in a 50°C environment.
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JPH11256111A (en) * 1998-03-11 1999-09-21 Nitto Denko Corp Pressure sensitive adhesive for surface-protecting film, and film for surface protection
JP2001123139A (en) * 1999-10-28 2001-05-08 Furukawa Electric Co Ltd:The Adhesive tape for semiconductor processing use
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