WO2021106997A1 - Double-sided pressure-sensitive adhesive tape - Google Patents

Double-sided pressure-sensitive adhesive tape Download PDF

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Publication number
WO2021106997A1
WO2021106997A1 PCT/JP2020/043990 JP2020043990W WO2021106997A1 WO 2021106997 A1 WO2021106997 A1 WO 2021106997A1 JP 2020043990 W JP2020043990 W JP 2020043990W WO 2021106997 A1 WO2021106997 A1 WO 2021106997A1
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Prior art keywords
double
adhesive tape
base material
weight
sided adhesive
Prior art date
Application number
PCT/JP2020/043990
Other languages
French (fr)
Japanese (ja)
Inventor
友也 川本
智 土居
桃子 原田
由紀菜 松井
博亮 前川
Original Assignee
積水化学工業株式会社
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Application filed by 積水化学工業株式会社 filed Critical 積水化学工業株式会社
Priority to CN202080039952.8A priority Critical patent/CN113924350A/en
Priority to KR1020217031356A priority patent/KR20220104105A/en
Priority to JP2020571861A priority patent/JPWO2021106997A1/ja
Publication of WO2021106997A1 publication Critical patent/WO2021106997A1/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
    • C09J7/00—Adhesives in the form of films or foils
    • C09J7/20—Adhesives in the form of films or foils characterised by their carriers
    • C09J7/22—Plastics; Metallised plastics
    • C09J7/26—Porous or cellular plastics
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B32—LAYERED PRODUCTS
    • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
    • B32B27/00—Layered products comprising a layer of synthetic resin
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B32—LAYERED PRODUCTS
    • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
    • B32B27/00—Layered products comprising a layer of synthetic resin
    • B32B27/06—Layered products comprising a layer of synthetic resin as the main or only constituent of a layer, which is next to another layer of the same or of a different material
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B32—LAYERED PRODUCTS
    • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
    • B32B5/00—Layered products characterised by the non- homogeneity or physical structure, i.e. comprising a fibrous, filamentary, particulate or foam layer; Layered products characterised by having a layer differing constitutionally or physically in different parts
    • B32B5/18—Layered products characterised by the non- homogeneity or physical structure, i.e. comprising a fibrous, filamentary, particulate or foam layer; Layered products characterised by having a layer differing constitutionally or physically in different parts characterised by features of a layer of foamed material
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B32—LAYERED PRODUCTS
    • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
    • B32B7/00—Layered products characterised by the relation between layers; Layered products characterised by the relative orientation of features between layers, or by the relative values of a measurable parameter between layers, i.e. products comprising layers having different physical, chemical or physicochemical properties; Layered products characterised by the interconnection of layers
    • B32B7/02—Physical, chemical or physicochemical properties
    • B32B7/022—Mechanical properties
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08G—MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
    • C08G18/00—Polymeric products of isocyanates or isothiocyanates
    • C08G18/06—Polymeric products of isocyanates or isothiocyanates with compounds having active hydrogen
    • C08G18/28—Polymeric products of isocyanates or isothiocyanates with compounds having active hydrogen characterised by the compounds used containing active hydrogen
    • C08G18/30—Low-molecular-weight compounds
    • C08G18/32—Polyhydroxy compounds; Polyamines; Hydroxyamines
    • C08G18/3203—Polyhydroxy compounds
    • C08G18/3206—Polyhydroxy compounds aliphatic
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08G—MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
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    • C08G18/30—Low-molecular-weight compounds
    • C08G18/34—Carboxylic acids; Esters thereof with monohydroxyl compounds
    • C08G18/348—Hydroxycarboxylic acids
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08G—MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
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    • C08G—MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
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    • C08G18/65—Low-molecular-weight compounds having active hydrogen with high-molecular-weight compounds having active hydrogen
    • C08G18/66—Compounds of groups C08G18/42, C08G18/48, or C08G18/52
    • C08G18/6666—Compounds of group C08G18/48 or C08G18/52
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    • C08G18/6674—Compounds of group C08G18/48 or C08G18/52 with compounds of group C08G18/32 or polyamines of C08G18/38 with compounds of group C08G18/3203
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    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08G—MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
    • C08G18/00—Polymeric products of isocyanates or isothiocyanates
    • C08G18/06—Polymeric products of isocyanates or isothiocyanates with compounds having active hydrogen
    • C08G18/28—Polymeric products of isocyanates or isothiocyanates with compounds having active hydrogen characterised by the compounds used containing active hydrogen
    • C08G18/65—Low-molecular-weight compounds having active hydrogen with high-molecular-weight compounds having active hydrogen
    • C08G18/66—Compounds of groups C08G18/42, C08G18/48, or C08G18/52
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    • C08G18/6692—Compounds of group C08G18/48 or C08G18/52 with compounds of group C08G18/34
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08G—MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
    • C08G18/00—Polymeric products of isocyanates or isothiocyanates
    • C08G18/06—Polymeric products of isocyanates or isothiocyanates with compounds having active hydrogen
    • C08G18/70—Polymeric products of isocyanates or isothiocyanates with compounds having active hydrogen characterised by the isocyanates or isothiocyanates used
    • C08G18/72—Polyisocyanates or polyisothiocyanates
    • C08G18/74—Polyisocyanates or polyisothiocyanates cyclic
    • C08G18/76—Polyisocyanates or polyisothiocyanates cyclic aromatic
    • C08G18/7657—Polyisocyanates or polyisothiocyanates cyclic aromatic containing two or more aromatic rings
    • C08G18/7664—Polyisocyanates or polyisothiocyanates cyclic aromatic containing two or more aromatic rings containing alkylene polyphenyl groups
    • C08G18/7671—Polyisocyanates or polyisothiocyanates cyclic aromatic containing two or more aromatic rings containing alkylene polyphenyl groups containing only one alkylene bisphenyl group
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
    • C08J9/00—Working-up of macromolecular substances to porous or cellular articles or materials; After-treatment thereof
    • C08J9/04—Working-up of macromolecular substances to porous or cellular articles or materials; After-treatment thereof using blowing gases generated by a previously added blowing agent
    • C08J9/12—Working-up of macromolecular substances to porous or cellular articles or materials; After-treatment thereof using blowing gases generated by a previously added blowing agent by a physical blowing agent
    • C08J9/122—Hydrogen, oxygen, CO2, nitrogen or noble gases
    • 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
    • C09J11/08—Macromolecular additives
    • 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
    • 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
    • C09J133/062—Copolymers with monomers not covered by C09J133/06
    • C09J133/066—Copolymers with monomers not covered by C09J133/06 containing -OH groups
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    • 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
    • C09J7/20—Adhesives in the form of films or foils characterised by their carriers
    • C09J7/22—Plastics; Metallised plastics
    • C09J7/25—Plastics; Metallised plastics based on macromolecular compounds obtained otherwise than by reactions involving only carbon-to-carbon unsaturated bonds
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    • 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
    • C09J7/20—Adhesives in the form of films or foils characterised by their carriers
    • C09J7/29—Laminated material
    • 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
    • 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]
    • 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]
    • C09J7/381—Pressure-sensitive adhesives [PSA] based on macromolecular compounds obtained by reactions involving only carbon-to-carbon unsaturated bonds
    • C09J7/385—Acrylic polymers
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
    • C08J2375/00—Characterised by the use of polyureas or polyurethanes; Derivatives of such polymers
    • C08J2375/04—Polyurethanes
    • C08J2375/08—Polyurethanes from polyethers
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    • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
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    • C09J2301/00—Additional features of adhesives in the form of films or foils
    • C09J2301/10—Additional features of adhesives in the form of films or foils characterized by the structural features of the adhesive tape or sheet
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    • C09J2301/124—Additional features of adhesives in the form of films or foils characterized by the structural features of the adhesive tape or sheet by the arrangement of layers the adhesive layer being present on both sides of the carrier, e.g. double-sided adhesive tape
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    • C09J—ADHESIVES; NON-MECHANICAL ASPECTS OF ADHESIVE PROCESSES IN GENERAL; ADHESIVE PROCESSES NOT PROVIDED FOR ELSEWHERE; USE OF MATERIALS AS ADHESIVES
    • C09J2301/00—Additional features of adhesives in the form of films or foils
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    • C09J2433/00—Presence of (meth)acrylic polymer
    • C09J2433/006—Presence of (meth)acrylic polymer in the substrate
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    • C09J2467/00—Presence of polyester
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    • C09J2475/00—Presence of polyurethane
    • C09J2475/006—Presence of polyurethane in the substrate

Definitions

  • the present invention relates to a double-sided adhesive tape.
  • Adhesive tapes are widely used for fixing electronic components. Specifically, for example, in a display device such as a television or a monitor, an adhesive tape is used to fix a cover panel on the surface to a housing. Such an adhesive tape is used, for example, in the shape of a frame or the like so as to be arranged around the display screen.
  • Patent Documents 1 and 2 have an acrylic pressure-sensitive adhesive layer laminated and integrated on at least one surface of a base material layer, and the base material layer is specific.
  • a shock absorbing tape which is a crosslinked polyolefin resin foam sheet having a degree of crosslinking and an aspect ratio of air bubbles is described.
  • the present invention provides a double-sided adhesive tape which is excellent in drop impact resistance, can reduce display unevenness of a display device, and can easily tear a foam base material when peeled from an adherend. With the goal.
  • the present invention is a double-sided adhesive tape having a foam base material and pressure-sensitive adhesive layers laminated on both sides of the foam base material, and the foam base material has a bubble volume fraction of 40% by volume or more. and 75% by volume or less, the shear breaking strength of a double-sided pressure-sensitive adhesive tape is 200 N / inch 2 or more 500 N / inch 2 or less.
  • the present invention will be described in detail below.
  • the present inventors have an X-ray CT (X-ray Computed Tomography) apparatus in a double-sided adhesive tape having a foam base material and adhesive layers laminated on both sides of the foam base material.
  • the bubble structure of the foam base material was analyzed using image analysis software, and the effect of the bubble structure on the performance of the double-sided adhesive tape was examined.
  • the present inventors adjust the volume fraction of the foam base material to a specific range, and further adjust the shear breaking strength of the foam base material to a specific range to obtain the strength of the foam base material. And found that both can be increased in flexibility.
  • the foam base material has a lower limit of 40% by volume and an upper limit of 75% by volume of the bubble volume fraction.
  • both the strength and flexibility of the foam base material can be increased, and at the same time, both can be achieved.
  • the bubble volume fraction is 40% by volume or more
  • the foam base material can have appropriate flexibility, so that display unevenness of the display device can be reduced, and the double-sided adhesive tape is adhered.
  • the foam base material can be easily torn when peeled from.
  • the bubble volume fraction is 75% by volume or less, it is possible to prevent the strength of the foam base material from being excessively lowered, so that the drop impact resistance of the double-sided adhesive tape can be improved.
  • the preferable lower limit of the bubble volume fraction is 42% by volume, the preferable upper limit is 70% by volume, the more preferable lower limit is 46% by volume, the more preferable upper limit is 67% by volume, the further preferable lower limit is 48% by volume, and further preferable.
  • the upper limit is 63% by volume, a particularly preferable lower limit is 50% by volume, and a particularly preferable upper limit is 60% by volume.
  • the bubble volume fraction is calculated by the following formula (1) using an X-ray CT apparatus and image analysis software.
  • Bubble volume fraction (volume%) bubble volume / volume of foam base material x 100 (1)
  • the bubble volume is the total volume of all bubbles contained in the foam base material of the sample to be measured.
  • the average and standard deviation of the major axis distribution of the bubbles of the foam base material are not particularly limited, but the preferable upper limit of the average of the major axis distribution of the bubbles is 55 ⁇ m, and the preferable upper limit of the standard deviation of the major axis distribution of the bubbles is 30 ⁇ m.
  • the drop impact resistance of the double-sided adhesive tape can be improved, the display unevenness of the display device can be reduced, and the foam base material can be easily pulled when the double-sided adhesive tape is peeled off from the adherend. Can be torn.
  • the bubbles are too large or the size of the bubbles varies, there are locally particularly low strength points in the foam base material, especially when the double-sided adhesive tape is used in a thin and narrow width. As a result, an impact is applied due to dropping or the like during transportation, so that the above-mentioned location is the starting point for interlayer destruction of the foam base material or peeling of the double-sided adhesive tape.
  • a more preferable upper limit of the average of the major axis distribution is 53 ⁇ m, a further preferable upper limit is 51 ⁇ m, and a further preferable upper limit is 49 ⁇ m.
  • the lower limit of the average of the major axis distribution is not particularly limited, and is determined depending on the bubble volume fraction and the thickness of the foam base material, but the practical lower limit is 10 ⁇ m.
  • a more preferred upper limit of the standard deviation of the major axis distribution is 28 ⁇ m, a further preferred upper limit is 27 ⁇ m, and a further preferred upper limit is 24 ⁇ m.
  • the foaming ratio of the bubbles in the foam base material is not particularly limited, but when the foam base material is a polyurethane foam, the preferable upper limit of the foaming ratio of the bubbles is 95% by volume.
  • the polyurethane foam has a continuous foam structure, and the continuous foam ratio is close to 100% by volume. Therefore, when the foam base material is a polyurethane foam, having a continuous foam ratio in the above range means that the continuous foam ratio is relatively low and the number of closed cells is large among the polyurethane foams. By adjusting the continuous foam ratio within the above range and increasing the number of closed cells, the strength and flexibility of the polyurethane foam can be further increased.
  • a more preferable upper limit of the continuous foam ratio is 93% by volume, and a more preferable upper limit is 91% by volume.
  • the lower limit of the continuous foaming ratio is not particularly limited, but the general lower limit of the continuous foaming ratio of the polyurethane foam is 90% by volume.
  • the continuous bubble ratio of bubbles is calculated by the following formula (2) using an X-ray CT apparatus and image analysis software.
  • Communication bubble ratio (volume%) communication bubble volume / bubble volume x 100 (2)
  • the communicating bubble volume is the total volume of all the communicating bubbles contained in the foam base material of the sample to be measured, and the bubble volume is included in the foam base material of the sample to be measured. It is the sum of the volumes of all the bubbles.
  • the more preferable upper limit of the flatness is 0.18, the further preferable upper limit is 0.16, and the even more preferable upper limit is 0.14.
  • the lower limit of the flatness is not particularly limited, and the closer it is to 0, the closer the bubbles are to a true sphere, and the more uniform the impact relaxation against dropping from all angles is preferable. Therefore, the practical lower limit is 0.05.
  • the aspect ratio of the bubbles in the foam base material is not particularly limited, but the preferable upper limit is 1.5. By adjusting the aspect ratio to the above range, the impact mitigation against dropping from any angle can be made more uniform, and the drop impact resistance of the double-sided adhesive tape can be improved.
  • a more preferable upper limit of the aspect ratio is 1.1, a further preferable upper limit is 1.09, and a further preferable upper limit is 1.07.
  • the lower limit of the aspect ratio is not particularly limited, and the closer it is to 1, the closer the bubbles are to a perfect circle, and the more uniform the impact relaxation against dropping from all angles is preferable. Therefore, the practical lower limit is 1.01.
  • the aspect ratio and flatness of the bubbles are calculated by the following equations (3) and (4) using an X-ray CT apparatus and image analysis software.
  • the X-ray CT apparatus and the image analysis software are not particularly limited, but the analysis using the X-ray CT apparatus and the image analysis software is performed in more detail, for example, as follows.
  • the central part of the measurement sample obtained by cutting the foam substrate was imaged with an X-ray CT device (for example, "TDM1000H-II (2K)" manufactured by Yamato Scientific Co., Ltd., resolution of about 1.5 ⁇ m / pixel).
  • An X-ray CT device for example, "TDM1000H-II (2K)" manufactured by Yamato Scientific Co., Ltd., resolution of about 1.5 ⁇ m / pixel.
  • a rectangular parallelepiped 3D image having a length of 1.5 mm, a width of 1.2 mm, and a height of 0.3 mm is obtained.
  • the obtained image is noise-removed and binarized by image analysis software (for example, "Avizo 9.2.0" manufactured by FEI), and each numerical value (foam volume fraction) representing the bubble structure of the foam base material is used. , Average and standard deviation of the major axis distribution of bubbles, continuous bubble rate of bubbles, aspect ratio of bubbles, flatness of bubbles, etc.).
  • image analysis software for example, "Avizo 9.2.0" manufactured by FEI
  • each numerical value (foam volume fraction) representing the bubble structure of the foam base material is used. , Average and standard deviation of the major axis distribution of bubbles, continuous bubble rate of bubbles, aspect ratio of bubbles, flatness of bubbles, etc.).
  • Mo is used
  • a lens L0270
  • noise is first removed by the Median Filter (Neighborhood value 26) function.
  • the threshold value is 90 out of 256 gradations.
  • whether the bubble is a closed bubble or a continuous bubble is determined by the presence or absence of a break in the continuous portion of the pixel.
  • the bubbles are first divided by contacts to obtain the center of gravity of the bubbles.
  • a rectangular parallelepiped having the center of gravity at the same position as the center of gravity and inscribed in the bubble is set, and the lengths of the three orthogonal sides are set to the major axis, the medium diameter, and the minor axis, respectively, from the longest.
  • bubbles having a major axis of less than 10 ⁇ m are excluded.
  • each numerical value representing the bubble structure of the foam base material (volume fraction of bubbles, average and standard deviation of major axis distribution of bubbles, continuous bubble rate of bubbles, aspect ratio of bubbles, flatness of bubbles, etc.) within the above range.
  • the method of doing so is not particularly limited.
  • the foam base material is a polyurethane foam
  • the type and content of polyisocyanate and polyol in the urethane resin composition the conditions for mixing air, nitrogen, etc. with the urethane resin composition, and the urethane resin composition.
  • the reaction conditions and the like when the urethane is heat-cured may be adjusted.
  • the bubble volume fraction can be adjusted by changing the type and content of polyisocyanate and polyol in the urethane resin composition, and the foaming conditions. Even when the raw materials are the same, it can be adjusted by changing the conditions for mixing air, nitrogen, etc. with the urethane resin composition, the reaction conditions for heating and curing the urethane resin composition, and the like. Further, the average and standard deviation of the major axis distribution of the bubbles can be reduced by adjusting by slowly advancing the urethanization reaction.
  • the foam base material may have a single-layer structure or a multi-layer structure.
  • the foam base material is not particularly limited, and examples thereof include polyurethane foams, polyolefin foams, and acrylic foams. Of these, polyurethane foam is preferable because it has appropriate flexibility and the bubble structure can be easily adjusted.
  • polyurethane foam examples include a polyurethane foam made of a urethane resin composition containing a polyisocyanate and a polyol. Such a polyurethane foam can be produced by heat-curing the urethane resin composition.
  • the polyisocyanate is not particularly limited, and examples thereof include aromatic polyisocyanates and aliphatic polyisocyanates used for general polyurethane foams. Of these, aromatic diisocyanates or aliphatic diisocyanates having two isocyanate groups in one molecule are preferable.
  • 4,4'-diphenylmethane diisocyanate is also generally referred to as "MDI" or "binuclear monomeric MDI". Of these, 4,4'-diphenylmethane diisocyanate (MDI) is preferable because a polyurethane foam having excellent flexibility can be easily obtained.
  • aromatic diisocyanates or aliphatic diisocyanates may be used alone or in combination of two or more.
  • the above-mentioned polyol is not particularly limited, and examples thereof include polyols used for general polyurethane foams. Specific examples thereof include polyether polyols, polyester polyols, and polyether ester polyols. Further, examples of the above-mentioned polyol include trifunctional polyether polyol, glycerin, trimethylolpropane and the like. These polyols may be used alone or in combination of two or more.
  • the above-mentioned polyether polyol is not particularly limited, and examples thereof include polypropylene glycol (PPG) and the like.
  • the polyester polyol is not particularly limited, and a polyester polyol composed of a polyol component and an acid component can be used.
  • the polyol preferably contains a short chain diol.
  • the strength of the polyurethane foam is increased. Therefore, in order to generate bubbles having a more uniform size and adjust the bubble structure, for example, the urethanization reaction is slowed down by increasing the content of the polyisocyanate in the urethane resin composition to increase the fluidity of the resin. Even in the case of proceeding to the above, it is possible to prevent the polyurethane foam from being excessively lowered in strength.
  • Examples of the short chain diol include 1,5-pentanediol, 1,6-hexamethylene diol, neopentyl glycol, ethylene glycol, diethylene glycol, propylene glycol, dipropylene glycol, 1,4-butanediol, neopentyl glycol and the like. Can be mentioned. These short chain diols may be used alone or in combination of two or more. Of these, 1,5-pentanediol or 1,6-hexamethylenediol is preferable because a high-strength polyurethane foam can be easily obtained. In addition, neopentyl glycol is preferable because it is easy to lower the continuous foam ratio.
  • the weight average molecular weight of the polyol is not particularly limited, but the preferred lower limit is 500 and the preferred upper limit is 5000.
  • the weight average molecular weight of the polyol is 500 or more, the polyurethane foam can have appropriate flexibility.
  • the weight average molecular weight of the polyol is 5000 or less, it is possible to prevent the strength of the polyurethane foam from being excessively lowered.
  • the more preferable lower limit of the weight average molecular weight of the polyol is 700, the more preferable upper limit is 2000, the more preferable lower limit is 800, and the further preferable upper limit is 1500.
  • a GPC apparatus for example, manufactured by Tosoh Corporation, product name "HLC-8220", column: TSKgelSuper HZM-N (4 pieces)
  • HLC-8220 column: TSKgelSuper HZM-N (4 pieces)
  • a flow rate of 0.5 mL / min can be adopted as the measurement conditions.
  • the isocyanate index of the polyisocyanate in the urethane resin composition is not particularly limited, but a preferable lower limit is 70 and a preferable upper limit is 120.
  • the isocyanate index is an index relating to the isocyanate equivalent in the reaction between isocyanate and an active hydrogen-containing compound.
  • the isocyanate index is less than 100, it means that the reactive group such as a hydroxyl group is more than the isocyanate group, and when the isocyanate index is more than 100, it means that the isocyanate group is more than the reactive group such as the hydroxyl group.
  • the isocyanate index is 70 or more, the cross-linking with the polyisocyanate is sufficient and the bubble structure can be easily adjusted.
  • the polyurethane foam can have an appropriate density, and the strength and flexibility are increased. ..
  • the isocyanate index is 120 or less, the degree of cross-linking of the polyurethane foam does not increase too much, and the glass transition point (Tg) becomes relatively low, so that the foam becomes easily stretchable and has high strength and flexibility. ..
  • the content of the polyisocyanate in the urethane resin composition is not particularly limited, but the urethanization reaction is slowly promoted by, for example, increasing the content of the polyisocyanate in the urethane resin composition to increase the fluidity of the resin. Therefore, it is preferable to adjust the bubble structure by generating bubbles having a more uniform size.
  • the preferable lower limit is 5% by weight and the preferable upper limit is 30% by weight with respect to 100% by weight of the polyol.
  • the urethanization reaction can be slowly promoted to generate bubbles having a more uniform size, so that the bubble structure can be easily adjusted and the polyurethane foam can be easily adjusted.
  • the content of the polyisocyanate is 30% by weight or less, the degree of cross-linking of the polyurethane foam does not increase too much and the glass transition point (Tg) becomes relatively low, so that the foam becomes stretchable and has strength and flexibility.
  • Tg glass transition point
  • the sex becomes high.
  • the more preferable lower limit of the content of the polyisocyanate is 15% by weight, and the more preferable upper limit is 25% by weight.
  • the urethane resin composition may contain a catalyst, if necessary.
  • the catalyst include organic tin compounds, organic zinc compounds, organic nickel compounds, organic iron compounds, metal catalysts, tertiary amine-based catalysts, and organic acid salts. Of these, organic tin compounds are preferable. These catalysts may be used alone or in combination of two or more.
  • the amount of the catalyst added is not particularly limited, but the preferable lower limit is 0.05 parts by weight, the preferable upper limit is 5.0 parts by weight, and the more preferable upper limit is 4.0 parts by weight with respect to 100 parts by weight of the polyol.
  • Examples of the organic tin compound include stanas octoate, dibutyltin diacetate, dibutyltin dilaurate and the like.
  • Examples of the organic zinc compound include zinc octylate and the like.
  • Examples of the organic nickel compound include nickel acetylacetone and nickel diacetylacetone.
  • Examples of the organic iron compound include iron acetylacetone.
  • Examples of the metal catalyst include alkoxides and phenoxides of alkali metals such as sodium acetate or alkaline earth metals.
  • tertiary amine-based catalyst examples include triethylamine, triethylenediamine, N-methylmorpholine dimethylaminomethylphenol, imidazole, 1,8-diazabicyclo [5.4.0] undecene and the like.
  • the urethane resin composition may contain a foaming agent, if necessary.
  • the foaming agent include foaming agents used for general polyurethane foams. Specific examples thereof include water, pentane, cyclopentane, hexane, cyclohexane, dichloromethane, carbon dioxide and the like.
  • the amount of the foaming agent added is not particularly limited and may be an appropriate amount, but when the foaming agent is water, it is usually about 0.1 to 3 parts by weight with respect to 100 parts by weight of the polyol. is there.
  • the urethane resin composition may contain a defoaming agent, if necessary.
  • the defoaming agent include silicone-based defoaming agents such as dimethylsiloxane, polyetherdimethylsiloxane, and phenylmethylsiloxane. Of these, polyetherdimethylsiloxane is preferable. Among the polyether dimethylsiloxanes, block copolymers of dimethylpolysiloxane and polyether are more preferable. These foam stabilizers may be used alone or in combination of two or more.
  • the amount of the foam stabilizer added is not particularly limited, but the preferable lower limit with respect to 100 parts by weight of the polyol is 0.2 parts by weight, the preferable upper limit is 7 parts by weight, the more preferable lower limit is 0.4 parts by weight, and the more preferable upper limit. Is 5 parts by weight.
  • the urethane resin composition may contain additives generally used in the production of polyurethane foams such as ultraviolet absorbers, antioxidants, organic fillers, inorganic fillers, and colorants. Good.
  • a method for producing the polyurethane foam for example, a urethane resin composition (liquid) obtained by mechanically mixing air, nitrogen, etc. and foaming is applied to the surface of a release liner or a resin film, and the applied urethane resin composition is applied.
  • a method of producing a foam by heat-curing the resin mechanical floss method and the like can be mentioned.
  • a method of reacting the polyisocyanate with the raw material for forming the polyurethane foam to generate a gas (chemical foaming method) and the like can be mentioned.
  • the mechanical floss method is preferable.
  • the polyurethane foam obtained by the mechanical floss method tends to have a higher density than the polyurethane foam obtained by the chemical foam method, and the bubble structure tends to be fine and uniform.
  • polyolefin foam examples include a foam made of a resin such as a polyethylene resin, a polypropylene resin, and a polybutadiene resin. Of these, polyethylene-based resins are preferable because flexible polyolefin foams can be easily obtained.
  • the foam substrate has a lower limit of shear breaking strength of 200 N / inch 2 and an upper limit of 500 N / inch 2 .
  • the shear breaking strength is 200 N / inch 2 or more, the strength of the foam base material is sufficiently high, and the drop impact resistance of the double-sided adhesive tape is improved.
  • the shear breaking strength is 500 N / inch 2 or less, it is possible to suppress the flexibility of the foam base material from being excessively lowered, so that display unevenness of the display device can be reduced, and the double-sided adhesive tape can be used.
  • the foam base material can be easily torn when the material is peeled off from the adherend.
  • the preferred lower limit of the shear breaking strength 220 N / inch 2 a preferred upper limit is 470N / inch 2, and more preferable lower limit is 240 N / inch 2, and more preferred upper limit is 450 N / inch 2, still more preferred lower limit 270N / inch 2.
  • a more preferable upper limit is 415 N / inch 2 .
  • FIG. 1 shows a schematic diagram showing a method for measuring shear breaking strength.
  • a test piece 18 having a size of 25 mm ⁇ 25 mm and two SUS plates 19 having a size of 125 mm ⁇ 50 mm and a thickness of 2 mm of double-sided adhesive tape are laminated as shown in FIG.
  • This laminate is crimped with a weight under the conditions of 5 kg and 10 seconds, and then allowed to stand for 24 hours to prepare a test sample in which two SUS plates 19 are bonded via a test piece 18.
  • the upper one of the other SUS plates 19 is placed in the direction perpendicular to the stacking direction of the SUS plates (in the figure, the arrow direction). It is pulled under the condition of 7 mm / min, and the force (breaking point strength) applied to the test piece 18 when the test piece 18 breaks is measured.
  • the test piece 18 breaks it means that the foam base material breaks between layers.
  • the shear breaking strength of the foam base material can be adjusted by changing the type and content of the polyisocyanate and the polyol in the urethane resin composition. Even when the raw materials are the same, it can be adjusted by setting the volume fraction of bubbles, the average of the major axis distribution of bubbles, the standard deviation, and the like within appropriate ranges.
  • the 25% compressive strength of the foam base material is not particularly limited, but the preferable lower limit is 0.015 MPa and the preferable upper limit is 0.08 MPa.
  • the 25% compression strength is 0.015 MPa or more, the strength of the foam base material is sufficiently high, and the drop impact resistance of the double-sided adhesive tape is improved.
  • the 25% compression strength is 0.08 MPa or less, it is possible to prevent the flexibility of the foam base material from being excessively lowered, so that the double-sided adhesive tape can be satisfactorily crimped, and the display device can be used. Display unevenness can be reduced, and the foam base material can be easily torn when the double-sided adhesive tape is peeled off from the adherend.
  • the more preferable lower limit of the 25% compression strength is 0.02 MPa, the more preferable upper limit is 0.07 MPa, the further preferable lower limit is 0.025 MPa, the further preferable upper limit is 0.065 MPa, and the further preferable lower limit is 0.03 MPa.
  • An even more preferable upper limit is 0.06 MPa.
  • the 25% compression strength can be determined by measuring in accordance with JIS K 6254: 2010.
  • the 25% compressive strength of the foam base material can be adjusted by changing the type and content of the polyisocyanate and the polyol in the urethane resin composition. Even when the raw materials are the same, it can be adjusted by setting the volume fraction of bubbles, the average of the major axis distribution of bubbles, the standard deviation, and the like within appropriate ranges.
  • the glass transition point of the foam base material is not particularly limited, but a preferable lower limit is ⁇ 30 ° C. and a preferable upper limit is 30 ° C.
  • a preferable lower limit is ⁇ 30 ° C. or higher
  • the foam base material exhibits good low resilience and can relieve stress.
  • the foam base material can have appropriate flexibility, and the foam becomes an easily stretchable foam, and the strength and flexibility are increased. ..
  • the more preferable lower limit of the glass transition point of the foam base material is ⁇ 25 ° C., and the more preferable upper limit is 20 ° C.
  • the double-sided adhesive tape of the present invention may further have a resin sheet on at least one side of the foam base material.
  • the resin sheet may be laminated on one side of the foam base material, or may be laminated on both sides.
  • the resin constituting the resin sheet is not particularly limited, and for example, polyester resin such as polyethylene terephthalate, acrylic resin, polyethylene resin, polypropylene resin, polyvinyl chloride, epoxy resin, silicone resin, phenol resin, polyimide, etc. Examples include polyester and polypropylene. Of these, acrylic resins, polyethylene resins, polypropylene resins, and polyester resins are preferable because of their excellent flexibility. Among the polyester-based resins, polyethylene terephthalate is preferable.
  • the resin constituting the resin sheet may be a thermoplastic resin.
  • the thermoplastic resin is not particularly limited, and for example, a styrene-based (co) polymer, an olefin-based (co) polymer, a vinyl chloride-based (co) polymer, a polyether ester-based triblock-based (co) polymer, and the like. Examples thereof include polyester-based (co) polymers, urethane-based (co) polymers, amide-based (co) polymers, and acrylic (co) polymers.
  • the resin sheet When the resin constituting the resin sheet is a thermoplastic resin, the resin sheet preferably has a tensile elastic modulus of 200 MPa or less.
  • a tensile elastic modulus of 200 MPa or less By using a flexible resin having a tensile elastic modulus of 200 MPa or less, the flexibility of the entire double-sided adhesive tape is ensured, the double-sided adhesive tape can be easily wound into a roll, and the handleability is remarkably improved.
  • the tensile elastic modulus can be measured by a method according to JIS K 7161. Specifically, for example, a resin sheet is punched into a dumbbell shape using a punching blade "Tension No. 1 type dumbbell shape" manufactured by Polymer Instruments Co., Ltd. to prepare a test piece.
  • the tensile elastic modulus of the obtained test piece is measured at a tensile speed of 100 mm / min using, for example, "Autograph AGS-X” manufactured by Shimadzu Corporation.
  • the tensile elastic modulus is calculated from the slope of the tensile strength between the strains of 1 to 3%.
  • the resin constituting at least one of the resin sheets is preferably a thermoplastic resin. That is, the double-sided adhesive tape of the present invention preferably has a resin sheet made of a thermoplastic resin.
  • the double-sided adhesive tape of the present invention comprises a first resin sheet laminated on the first surface of the foam base material and a second resin sheet laminated on the second surface of the foam base material. At least one selected from the group consisting of the first resin sheet and the second resin sheet is preferably a resin sheet composed of a thermoplastic resin.
  • the thickness of the resin sheet is not particularly limited, but the preferable lower limit is 10 ⁇ m and the preferable upper limit is 100 ⁇ m. If the thickness of the resin sheet is 10 ⁇ m or more, the resin sheet is less likely to break even when the resin sheet is pulled. When the thickness of the resin sheet is 100 ⁇ m or less, it is possible to suppress a decrease in followability to the adherend.
  • a more preferable lower limit of the thickness of the resin sheet is 15 ⁇ m, a more preferable upper limit is 80 ⁇ m, a further preferable lower limit is 20 ⁇ m, a further preferable upper limit is 60 ⁇ m, a further preferable lower limit is 25 ⁇ m, and a further preferable upper limit is 50 ⁇ m.
  • the resin sheet may be colored.
  • coloring the resin sheet it is possible to impart light-shielding properties to the double-sided adhesive tape.
  • the method of coloring the resin sheet is not particularly limited, and for example, a method of kneading particles such as carbon black or titanium oxide or fine bubbles into the resin constituting the resin sheet, or applying ink to the surface of the resin sheet. The method and the like can be mentioned.
  • the pressure-sensitive adhesive layers laminated on both sides of the foam base material may have the same composition or different compositions.
  • the pressure-sensitive adhesive layer is not particularly limited, and examples thereof include a pressure-sensitive adhesive layer made of an acrylic pressure-sensitive adhesive, a rubber-based pressure-sensitive adhesive, a urethane pressure-sensitive adhesive, a silicone-based pressure-sensitive adhesive, and the like.
  • acrylic containing an acrylic copolymer and a tackifier because the adhesive strength can be easily adjusted, it is relatively stable against light, heat, moisture, etc., and it can be applied to various adherends.
  • It is preferably a pressure-sensitive adhesive layer made of a pressure-sensitive adhesive.
  • the acrylic copolymer is obtained by copolymerizing a monomer mixture.
  • the monomer mixture may be subjected to a radical reaction in the presence of a polymerization initiator.
  • a method of radically reacting the monomer mixture that is, a polymerization method
  • examples thereof include solution polymerization (boiling point polymerization or constant temperature polymerization), emulsion polymerization, suspension polymerization, and bulk polymerization.
  • the reaction method for radically reacting the monomer mixture include living radical polymerization and free radical polymerization.
  • the ratio of the weight average molecular weight (Mw) to the number average molecular weight (Mn) of the acrylic copolymer is not particularly limited, but the preferable lower limit is 1.05 and the preferable upper limit is 5.0. ..
  • Mw / Mn molecular weight distribution
  • the more preferable upper limit of the molecular weight distribution (Mw / Mn) is 3.0, the more preferable upper limit is 2.5, and the particularly preferable upper limit is 2.3.
  • the polymerization conditions such as the polymerization initiator and the polymerization temperature may be adjusted.
  • the number average molecular weight (Mn) and the weight average molecular weight (Mw) are standard polystyrene-equivalent molecular weights obtained by GPC (Gel Permeation Chromatography: Gel Permeation Chromatography). In GPC, for example, 2690 Separations Model (manufactured by Waters) or the like can be used.
  • a GPC apparatus for example, manufactured by Tosoh Corporation, product name "HLC-8220", column: TSKgelSuper HZM-N (4 pieces)
  • tetrahydrofuran can be used as a solvent
  • a measurement condition for example, 40 ° C. and a flow rate of 0.5 mL / min can be adopted.
  • the acrylic copolymer When the molecular weight distribution (Mw / Mn) of the acrylic copolymer is 2.5 or less, the acrylic copolymer preferably contains a structural unit derived from 2-ethylhexyl acrylate. When the molecular weight distribution (Mw / Mn) of the acrylic copolymer is 2.5 or less, the content of the structural unit derived from the 2-ethylhexyl acrylate is not particularly limited, but the preferable lower limit is 80% by weight and the preferable upper limit. Is 98% by weight.
  • the content of the structural unit is 80% by weight or more, the glass transition point of the acrylic copolymer is lowered, the wettability of the pressure-sensitive adhesive layer to the adherend is high, and the drop impact resistance of the double-sided adhesive tape is high. Is improved.
  • the content of the structural unit is 98% by weight or less, the cohesive force of the pressure-sensitive adhesive layer is increased, and the drop impact resistance of the double-sided pressure-sensitive adhesive tape is improved.
  • a more preferable lower limit of the content of the structural unit is 90% by weight, and a more preferable upper limit is 97% by weight.
  • the acrylic copolymer is a structural unit derived from a (meth) acrylic acid alkyl ester having an alkyl group having 4 or less carbon atoms. Is preferably contained.
  • the (meth) acrylic acid alkyl ester having an alkyl group having 4 or less carbon atoms is not particularly limited.
  • Examples of the (meth) acrylic acid alkyl ester having an alkyl group having 4 or less carbon atoms include methyl (meth) acrylate, ethyl (meth) acrylate, n-propyl (meth) acrylate, isopropyl (meth) acrylate, and n-. Butyl (meth) acrylate and the like can be mentioned. Of these, ethyl (meth) acrylate and n-butyl (meth) acrylate are preferable, and these acrylates are more preferable.
  • These (meth) acrylic acid alkyl esters having an alkyl group having 4 or less carbon atoms may be used alone or in combination of two or more.
  • the content of the structural unit derived from the (meth) acrylic acid alkyl ester having an alkyl group having 4 or less carbon atoms is particularly limited.
  • the preferred lower limit is 40% by weight and the preferred upper limit is 80% by weight.
  • the content of the structural unit is 40% by weight or more, the cohesive force of the pressure-sensitive adhesive layer is increased, and the drop impact resistance of the double-sided pressure-sensitive adhesive tape is improved.
  • the content of the structural unit is 80% by weight or less, it is possible to suppress the wettability of the pressure-sensitive adhesive layer from being excessively lowered to the adherend, and the drop impact resistance of the double-sided pressure-sensitive adhesive tape is improved.
  • the acrylic copolymer When the molecular weight distribution (Mw / Mn) of the acrylic copolymer is 2.5 or more, the acrylic copolymer preferably contains a structural unit derived from 2-ethylhexyl acrylate.
  • the content of the structural unit derived from the 2-ethylhexyl acrylate is not particularly limited, but the preferable lower limit is 10% by weight and the preferable upper limit. Is 40% by weight.
  • the content of the structural unit is 10% by weight or more, the cohesive force of the pressure-sensitive adhesive layer is increased, and the drop impact resistance of the double-sided pressure-sensitive adhesive tape is improved.
  • the content of the structural unit When the content of the structural unit is 40% by weight or less, it is possible to suppress the cohesive force of the pressure-sensitive adhesive layer from being excessively lowered, and the drop impact resistance of the double-sided pressure-sensitive adhesive tape is improved.
  • the acrylic copolymer can be copolymerized, if necessary, other than the structural unit derived from the 2-ethylhexyl acrylate and the structural unit derived from the (meth) acrylic acid alkyl ester having an alkyl group having 4 or less carbon atoms. It may contain structural units derived from other polymerizable monomers.
  • the other copolymerizable monomer include a (meth) acrylic acid alkyl ester having an alkyl group having 13 to 18 carbon atoms, a functional monomer and the like.
  • Examples of the (meth) acrylic acid alkyl ester having an alkyl group having 13 to 18 carbon atoms include tridecylic methacrylate and stearyl (meth) acrylic acid.
  • Examples of the functional monomer include hydroxyalkyl (meth) acrylic acid, glycerin dimethacrylate, glycidyl (meth) acrylate, 2-methacryloyloxyethyl isocyanate, (meth) acrylic acid, itaconic acid, maleic anhydride, and crotonic acid. Maleic acid, fumaric acid and the like can be mentioned. These other copolymerizable monomers may be used alone or in combination of two or more.
  • a functional monomer having a polar functional group such as a hydroxyl group or a carboxyl group is preferable, and a functional monomer having a hydroxyl group is preferable because the gel fraction of the pressure-sensitive adhesive layer can be easily adjusted by forming a cross-linked structure with the cross-linking agent.
  • Functional monomers are more preferred. That is, the acrylic copolymer preferably contains a hydroxyl group.
  • the weight average molecular weight (Mw) of the acrylic copolymer has a preferable lower limit of 300,000 and a preferable upper limit of 2 million.
  • the pressure-sensitive adhesive layer has an appropriate hardness, sufficient cohesive force, and high adhesive force.
  • the weight average molecular weight is 2 million or less, the adhesive strength of the pressure-sensitive adhesive layer is sufficient.
  • the more preferable lower limit of the weight average molecular weight is 500,000, and the more preferable upper limit is 1.4 million.
  • the polymerization conditions such as the polymerization initiator and the polymerization temperature may be adjusted.
  • Examples of the polymerization initiator include organic peroxides and azo compounds.
  • Examples of the organic peroxide include 1,1-bis (t-hexyl peroxy) -3,3,5-trimethylcyclohexane, t-hexyl peroxypivalate, t-butylperoxypivalate, 2,5.
  • the azo compound is not particularly limited as long as it is generally used for radical polymerization.
  • azo compound examples include 2,2'-azobis (isobutyronitrile), 2,2'-azobis (2-methylbutyronitrile), and 2,2'-azobis (2,4-dimethylvaleronitrile).
  • 1,1-azobis (cyclohexane-1-carbonitrile) 1-[(1-cyano-1-methylethyl) azo] Formamide
  • 4,4'-azobis (4-cyanovalerian acid) dimethyl-2,2'-azobis (2-methylpropionate), dimethyl-1,1'-azobis (1-cyclohexanecarboxylate)
  • the polymerization initiator that initiates living radical polymerization is not particularly limited, but an organic tellurium polymerization initiator is preferable. These polymerization initiators may be used alone or in combination of two or more.
  • a dispersion stabilizer may be used when the above-mentioned monomer mixture is radically reacted.
  • the dispersion stabilizer include polyvinylpyrrolidone, polyvinyl alcohol, methyl cellulose, ethyl cellulose, poly (meth) acrylic acid, poly (meth) acrylic acid ester, polyethylene glycol and the like.
  • the polymerization solvent is not particularly limited.
  • a non-polar solvent such as hexane, cyclohexane, octane, toluene, or xylene can be used.
  • a highly polar solvent such as water, methanol, ethanol, propanol, butanol, acetone, methyl ethyl ketone, methyl isobutyl ketone, tetrahydrofuran, dioxane, N, N-dimethylformamide can be used.
  • These polymerization solvents may be used alone or in combination of two or more.
  • the polymerization temperature is preferably 0 to 110 ° C. from the viewpoint of the polymerization rate.
  • tackifier examples include rosin-based resin, rosin ester-based resin, hydrogenated rosin-based resin, terpene-based resin, terpene phenol-based resin, kumaron inden-based resin, alicyclic saturated hydrocarbon-based resin, and C5-based petroleum.
  • resins examples include resins, C9-based petroleum resins, and C5-C9 copolymerized petroleum resins.
  • These tackifiers may be used alone or in combination of two or more. Of these, a rosin-based resin or a terpene-based resin is preferable, and a rosin-based resin containing a hydroxyl group or a terpene-based resin containing a hydroxyl group is more preferable.
  • the pressure-sensitive adhesive has a preferable lower limit of the softening temperature of 70 ° C. and a preferred upper limit of 170 ° C.
  • the softening temperature is 70 ° C. or higher, it is possible to prevent the pressure-sensitive adhesive layer from becoming too soft and reducing the drop impact resistance of the double-sided adhesive tape.
  • the softening temperature is 170 ° C. or lower, the wettability of the pressure-sensitive adhesive layer to the adherend is high, and the drop impact resistance of the double-sided pressure-sensitive adhesive tape is improved.
  • a more preferable lower limit of the softening temperature is 120 ° C.
  • the softening temperature is a softening temperature measured by the JIS K2207 ring-and-ball method.
  • the tackifier has a preferred lower limit of 25 and a preferred upper limit of the hydroxyl value of 160.
  • the hydroxyl value is within the above range, the wettability of the pressure-sensitive adhesive layer to the adherend is increased, and the drop impact resistance of the double-sided adhesive tape is improved.
  • the more preferable lower limit of the hydroxyl value is 30, and the more preferable upper limit is 150.
  • the hydroxyl value can be measured by JIS K1557 (phthalic anhydride method).
  • the content of the tackifier is not particularly limited, but the preferable lower limit with respect to 100 parts by weight of the acrylic copolymer is 10 parts by weight, and the preferable upper limit is 60 parts by weight.
  • the content of the pressure-sensitive adhesive is 10 parts by weight or more, the adhesive strength of the pressure-sensitive adhesive layer is high.
  • the content of the pressure-sensitive adhesive is 60 parts by weight or less, it is possible to prevent the pressure-sensitive adhesive layer from becoming too hard and reducing the adhesive strength.
  • the pressure-sensitive adhesive layer has a cross-linked structure formed between the main chains of the resin (for example, the acrylic copolymer, the pressure-sensitive adhesive, etc.) constituting the pressure-sensitive adhesive layer by adding a cross-linking agent.
  • a cross-linking agent for example, the acrylic copolymer, the pressure-sensitive adhesive, etc.
  • the above-mentioned cross-linking agent is not particularly limited, and examples thereof include isocyanate-based cross-linking agents, aziridine-based cross-linking agents, epoxy-based cross-linking agents, and metal chelate-type cross-linking agents. Of these, isocyanate-based cross-linking agents are preferable.
  • the preferable lower limit is 0.01 parts by weight and the preferable upper limit is 10 parts by weight with respect to 100 parts by weight of the acrylic copolymer, the more preferable lower limit is 0.1 parts by weight, and the more preferable upper limit is 3. It is a part by weight.
  • the pressure-sensitive adhesive layer may contain a silane coupling agent for the purpose of improving the adhesive strength.
  • the silane coupling agent is not particularly limited, and examples thereof include epoxysilanes, acrylicsilanes, methacrylsilanes, aminosilanes, and isocyanatesilanes.
  • the pressure-sensitive adhesive layer may contain a coloring material for the purpose of imparting light-shielding properties.
  • the coloring material is not particularly limited, and examples thereof include carbon black, aniline black, and titanium oxide. Of these, carbon black is preferable because it is relatively inexpensive and chemically stable.
  • the gel fraction of the pressure-sensitive adhesive layer is not particularly limited, but the preferable lower limit is 1% by weight and the preferable upper limit is 90% by weight.
  • the gel fraction is 1% by weight or more, the cohesive force of the pressure-sensitive adhesive layer is increased, and the drop impact resistance of the double-sided pressure-sensitive adhesive tape is improved.
  • the gel fraction is 90% by weight or less, it is possible to suppress the wettability of the pressure-sensitive adhesive layer from being excessively lowered to the adherend, and the drop impact resistance of the double-sided pressure-sensitive adhesive tape is improved.
  • the more preferable lower limit of the gel fraction is 20% by weight, the more preferable upper limit is 70% by weight, the further preferable lower limit is 30% by weight, and the further preferable upper limit is 50% by weight.
  • the gel fraction of the pressure-sensitive adhesive layer can be measured by the following method.
  • a test piece is prepared by cutting the double-sided adhesive tape into a flat rectangular shape of 50 mm ⁇ 100 mm.
  • the test piece is immersed in ethyl acetate at 23 ° C. for 24 hours, then removed from ethyl acetate and dried under the condition of 110 ° C. for 1 hour.
  • the weight of the test piece after drying is measured, and the gel fraction is calculated using the following formula (5). It is assumed that the test piece is not laminated with a release film for protecting the pressure-sensitive adhesive layer.
  • the thickness of the pressure-sensitive adhesive layer is not particularly limited, but the preferable lower limit of the thickness of the pressure-sensitive adhesive layer on one side is 20 ⁇ m, and the preferable upper limit is 100 ⁇ m. When the thickness of the pressure-sensitive adhesive layer is 20 ⁇ m or more, the adhesive strength of the pressure-sensitive adhesive layer is sufficient. When the thickness of the pressure-sensitive adhesive layer is 100 ⁇ m or less, the stress relaxation property of the foam base material can sufficiently contribute to the stress relaxation property of the double-sided adhesive tape as a whole.
  • a more preferable lower limit of the thickness of the pressure-sensitive adhesive layer is 25 ⁇ m, a more preferable upper limit is 80 ⁇ m, a further preferable lower limit is 30 ⁇ m, a further preferable upper limit is 70 ⁇ m, a further preferable lower limit is 35 ⁇ m, and a further preferable upper limit is 65 ⁇ m. ..
  • the thickness of the pressure-sensitive adhesive layer can be measured using a dial thickness gauge (for example, "ABS Digimatic Indicator" manufactured by Mitutoyo Co., Ltd.).
  • the thickness of the double-sided adhesive tape of the present invention is not particularly limited, but a preferable lower limit is 100 ⁇ m and a preferable upper limit is 1200 ⁇ m. When the thickness is 100 ⁇ m or more, the adhesive strength of the double-sided adhesive tape is sufficient, and the stress relaxation property is also sufficient. When the thickness is 1200 ⁇ m or less, sufficient adhesion and fixing with the double-sided adhesive tape can be realized.
  • a more preferable lower limit of the thickness is 250 ⁇ m, a more preferable upper limit is 900 ⁇ m, a further preferable lower limit is 350 ⁇ m, a further preferable upper limit is 700 ⁇ m, a further preferable lower limit is 400 ⁇ m, and a further preferable upper limit is 650 ⁇ m.
  • Examples of the method for producing the double-sided adhesive tape of the present invention include the following methods. First, a solvent is added to an acrylic copolymer, a pressure-sensitive adhesive, a cross-linking agent, etc. to prepare a solution of the pressure-sensitive adhesive A, and the solution of the pressure-sensitive adhesive A is applied to the surface of the foam base material. The solvent in the solution is completely dried and removed to form the pressure-sensitive adhesive layer A. Next, the release film is superposed on the formed pressure-sensitive adhesive layer A so that the release-treated surface faces the pressure-sensitive adhesive layer A. Next, a release film different from the release film is prepared, a solution of the adhesive B is applied to the release-treated surface of the release film, and the solvent in the solution is completely dried and removed to release the film.
  • a laminated film in which the pressure-sensitive adhesive layer B is formed on the surface of the mold film is produced.
  • the obtained laminated film is laminated on the back surface of the foam base material on which the pressure-sensitive adhesive layer A is formed so that the pressure-sensitive adhesive layer B faces the back surface of the foam base material to prepare a laminate.
  • the laminate is pressed by a rubber roller or the like. This makes it possible to obtain a double-sided adhesive tape having adhesive layers on both sides of the foam base material and having the surface of the adhesive layer covered with a release film.
  • two sets of laminated films are produced in the same manner, and these laminated films are laminated on both sides of the foam base material by laminating the pressure-sensitive adhesive layer of the laminated film on each side of the foam base material so as to face the foam base material.
  • a body may be produced and the laminated body may be pressurized with a rubber roller or the like. This makes it possible to obtain a double-sided adhesive tape having adhesive layers on both sides of the foam base material and having the surface of the adhesive layer covered with a release film.
  • the use of the double-sided adhesive tape of the present invention is not particularly limited, and is used, for example, for fixing parts in an electronic device.
  • the electronic device is not particularly limited, and examples thereof include a television, a monitor, a portable electronic device, an in-vehicle electronic device, and the like.
  • the double-sided adhesive tape of the present invention is suitably used for fixing parts in display devices such as televisions and monitors, particularly in relatively large display devices.
  • display devices such as televisions and monitors, particularly in relatively large display devices.
  • the surface cover panel in the above display device Is used to fix the housing to the housing. Since the double-sided adhesive tape of the present invention has excellent drop impact resistance and can reduce display unevenness of the display device, it is a case where parts are fixed by a narrow double-sided adhesive tape in a relatively large display device.
  • the double-sided adhesive tape of the present invention may have a narrow width, and the width is not particularly limited, but a preferable lower limit is 1000 ⁇ m, a preferable upper limit is 10000 ⁇ m, a more preferable lower limit is 1500 ⁇ m, and a more preferable upper limit is 5000 ⁇ m.
  • the shape of the double-sided adhesive tape of the present invention in these applications is not particularly limited, and examples thereof include a rectangle, a frame, a circle, an ellipse, and a donut. Further, the double-sided adhesive tape of the present invention may be used for the interior and exterior of vehicles, home appliances (for example, TVs, air conditioners, refrigerators, etc.).
  • a double-sided adhesive tape which is excellent in drop impact resistance, can reduce display unevenness of a display device, and can easily tear a foam base material when peeled from an adherend. can do.
  • Polyisocyanate (dinuclear monomeric MDI, manufactured by Tosoh Corporation) was adjusted and added thereto so as to have an isocyanate index of 85. Then, it was mixed and stirred with nitrogen gas so as to be 0.2 g / cm 3, and a solution containing fine bubbles was obtained. The solution was applied to a predetermined thickness on a PET separator (manufactured by nippers, V-2) having a thickness of 50 ⁇ m using an applicator, and the foam raw material was reacted to obtain a polyurethane foam. The shear breaking strength, 25% compressive strength, and thickness of the polyurethane foam were measured.
  • a polyurethane foam was obtained in the same manner as in the production of polyurethane foam 1-1 (PU1-1) except for the following points.
  • PPG polypropylene glycol
  • 5 parts by weight of 1,5-pentanediol 5 parts by weight of 1,6-hexamethylenediol were used.
  • Polyisocyanate (dinuclear monomeric MDI, manufactured by Tosoh Corporation) was adjusted to have an isocyanate index of 85 and charged.
  • a polyurethane foam was obtained in the same manner as in the production of polyurethane foam 1-1 (PU1-1) except for the following points.
  • the polyol 90 parts by weight of polypropylene glycol (PPG) (weight average molecular weight 1000), 5 parts by weight of 1,5-pentanediol, and 5 parts by weight of neopentyl glycol were used.
  • PPG polypropylene glycol
  • polyurethane foam 2 (Manufacturing of polyurethane foam 2 (PU2)) A polyurethane foam was obtained in the same manner as in the production of polyurethane foam 1-1 (PU1-1) except for the following points.
  • the polyol 85 parts by weight of polypropylene glycol (PPG) (weight average molecular weight 1000), 3 parts by weight of 1,6-hexamethylenediol, 3 parts by weight of neopentyl glycol, and 9 parts by weight of ⁇ -caprolactone were used.
  • Polyisocyanate Polymeric MDI, manufactured by Tosoh Corporation was adjusted to have an isocyanate index of 90 and charged.
  • a polyurethane foam was obtained in the same manner as in the production of polyurethane foam 1-1 (PU1-1) except for the following points.
  • PPG polypropylene glycol
  • ⁇ -caprolactone 9 parts by weight of ⁇ -caprolactone were used.
  • Polyisocyanate Polymeric MDI, manufactured by Tosoh Corporation was adjusted to have an isocyanate index of 100 and charged.
  • the nitrogen gas to be mixed was adjusted, and the thickness when the solution containing fine bubbles was applied onto a PET separator (manufactured by nippers, V-2) having a thickness of 50 ⁇ m was changed (thinned).
  • a polyurethane foam was obtained in the same manner as in the production of polyurethane foam 1-1 (PU1-1) except for the following points.
  • PU3-2 Polyurethane foam 1-1
  • Polyol 91 parts by weight of polypropylene glycol (PPG) (weight average molecular weight 1000) and 9 parts by weight of ⁇ -caprolactone were used.
  • PPG polypropylene glycol
  • Polyisocyanate Polymeric MDI, manufactured by Tosoh Corporation was adjusted to have an isocyanate index of 100 and charged.
  • a polyurethane foam was obtained in the same manner as in the production of polyurethane foam 1-1 (PU1-1) except for the following points.
  • PPG polypropylene glycol
  • 5 parts by weight of 1,5-pentanediol 5 parts by weight of 1,6-hexamethylenediol were used.
  • Polyisocyanate (dinuclear monomeric MDI, manufactured by Tosoh Corporation) was adjusted to have an isocyanate index of 75 and charged.
  • a polyurethane foam was obtained in the same manner as in the production of polyurethane foam 1-1 (PU1-1) except for the following points.
  • PPG polypropylene glycol
  • 1,6-hexamethylenediol were used.
  • Polyisocyanate dinuclear monomeric MDI, manufactured by Tosoh Corporation was adjusted to have an isocyanate index of 95 and charged.
  • a polyurethane foam was obtained in the same manner as in the production of polyurethane foam 1-1 (PU1-1) except for the following points.
  • PPG polypropylene glycol
  • NPG polypropylene glycol
  • Polyisocyanate dinuclear monomeric MDI, manufactured by Tosoh Corporation was adjusted to have an isocyanate index of 70 and charged.
  • a polyurethane foam was obtained in the same manner as in the production of polyurethane foam 1-1 (PU1-1) except for the following points.
  • PPG polypropylene glycol
  • ⁇ -caprolactone 9 parts by weight of ⁇ -caprolactone were used.
  • Polyisocyanate Polymeric MDI, manufactured by Tosoh Corporation was adjusted to have an isocyanate index of 110 and charged.
  • a polyurethane foam was obtained in the same manner as in the production of polyurethane foam 3-1 (PU3-1) except for the following points.
  • PPG polypropylene glycol
  • ⁇ -caprolactone 9 parts by weight of ⁇ -caprolactone were used.
  • Polyisocyanate Polymeric MDI, manufactured by Tosoh Corporation was adjusted to have an isocyanate index of 85 and charged.
  • a polyurethane foam was obtained in the same manner as in the production of polyurethane foam 1-1 (PU1-1) except for the following points.
  • Polyisocyanate dinuclear monomeric MDI, manufactured by Tosoh Corporation
  • the nitrogen gas to be mixed was adjusted, and the thickness when the solution mixed with fine bubbles was applied onto a PET separator (manufactured by nippers, V-2) having a thickness of 50 ⁇ m was changed (thickened).
  • a polyurethane foam was obtained in the same manner as in the production of polyurethane foam 1-1 (PU1-1) except for the following points.
  • the polyol 30 parts by weight of polypropylene glycol (PPG) (weight average molecular weight 1000), 60 parts by weight of polypropylene glycol (PPG) (weight average molecular weight 3100), and 10 parts by weight of 1,5-pentanediol were used.
  • Polyisocyanate Polymeric MDI, manufactured by Tosoh Corporation
  • the nitrogen gas to be mixed was adjusted, and the thickness when the solution mixed with fine bubbles was applied onto a PET separator (manufactured by nippers, V-2) having a thickness of 50 ⁇ m was changed (thickened).
  • a polyurethane foam was obtained in the same manner as in the production of polyurethane foam 1-1 (PU1-1) except for the following points.
  • the polyol 20 parts by weight of polypropylene glycol (PPG) (weight average molecular weight 1000), 70 parts by weight of polypropylene glycol (PPG) (weight average molecular weight 3100), and 10 parts by weight of 1,5-pentanediol were used.
  • Polyisocyanate Polymeric MDI, manufactured by Tosoh Corporation
  • the nitrogen gas to be mixed was adjusted, and the thickness when the solution mixed with fine bubbles was applied onto a PET separator (manufactured by nippers, V-2) having a thickness of 50 ⁇ m was changed (thickened).
  • Polyethylene foam 1 (PE1)) XLIM # 15003 (manufactured by Sekisui Chemical Co., Ltd.) was used as the polyethylene foam.
  • the weight average molecular weight (Mw) and the molecular weight distribution (Mw / Mn) of the obtained acrylic copolymer were determined. Specifically, the obtained acrylic copolymer-containing solution was diluted 50-fold with tetrahydrofuran (THF), and the obtained diluted solution was filtered through a filter (material: polytetrafluoroethylene, pore diameter: 0.2 ⁇ m). .. The obtained filtrate was supplied to a gel permeation chromatograph (manufactured by Waters, 2690 Separations Model), and GPC measurement was performed under the conditions of a sample flow rate of 1 ml / min and a column temperature of 40 ° C. to convert the acrylic copolymer into polystyrene.
  • THF tetrahydrofuran
  • the molecular weight was measured to determine the weight average molecular weight and the molecular weight distribution (Mw / Mn).
  • the weight average molecular weight was 1 million, and the molecular weight distribution (Mw / Mn) was 2.6.
  • a GPC KF-806L manufactured by Showa Denko KK was used as the column, and a differential refractometer was used as the detector.
  • Ethyl acetate was added to 100 parts by weight of the non-volatile content of the obtained acrylic copolymer-containing solution and stirred, and 5 parts by weight of a cross-linking agent (isocyanate-based cross-linking agent, Coronate L-55E, manufactured by Toso Co., Ltd.) and a tackifier were added. A total of 30 parts by weight was added and stirred to obtain a pressure-sensitive adhesive I having a non-volatile content of 30% by weight.
  • a cross-linking agent isocyanate-based cross-linking agent, Coronate L-55E, manufactured by Toso Co., Ltd.
  • tackifier 10 parts by weight of a hydrogenated rosin resin (softening point 100 ° C., hydroxyl value 40 mgKOH / g), 10 parts by weight of a rosin ester resin (softening point 150 ° C., hydroxyl value 40 mgKOH / g), terpene phenol type. 10 parts by weight of a resin (softening point 150 ° C., hydroxyl value 40 mgKOH / g) was used.
  • the pressure-sensitive adhesive I was applied to the support layer 1 (resin sheet) and dried at 100 ° C. for 5 minutes to form the pressure-sensitive adhesive layer 1 having a thickness of 20 ⁇ m.
  • One side of the foam base material was pressure-bonded to the pressure-sensitive adhesive layer 1 to prepare a laminated body in which the support layer 1 and the foam base material were laminated via the pressure-sensitive adhesive layer 1.
  • the support layer 1 (resin sheet) polyethylene terephthalate (PET) (X30, manufactured by Toray Industries, Inc., thickness 50 ⁇ m) was used.
  • the support layer 2 (resin sheet) is heat-sealed to the other surface of the foam base material, and the support layer 1, the pressure-sensitive adhesive layer 1, the foam base material, and the support layer 2 are laminated in this order.
  • the support layer 2 (resin sheet)
  • a release paper having a thickness of 150 ⁇ m is prepared, the adhesive I is applied to the release-treated surface of the release paper, and the adhesive layer 2 is formed at 100 ° C.
  • the pressure-sensitive adhesive layer 2 was bonded to the surface of the support layer 1 (resin sheet) laminated on the foam base material.
  • the pressure-sensitive adhesive layer 3 having the same structure as the pressure-sensitive adhesive layer 2 was bonded to the surface of the support layer 2 (resin sheet) opposite to the foam base material. Then, it was cured by heating at 40 degreeC for 48 hours. As a result, a double-sided adhesive tape covered with a release paper was obtained.
  • the tensile elastic modulus of the support layer 2 (resin sheet) was 10 MPa and 108 MPa, respectively.
  • the obtained double-sided adhesive tape was cut into a flat rectangular shape of 50 mm ⁇ 100 mm to prepare a test piece, and the test piece was immersed in ethyl acetate at 23 ° C. for 24 hours, then taken out from ethyl acetate and taken out at 110 ° C. It was dried under the conditions for 1 hour. The weight of the test piece after drying was measured, and the gel fraction of the pressure-sensitive adhesive layer was calculated using the following formula (5). As a result, the gel fraction of the pressure-sensitive adhesive layer was 42% by weight.
  • FIG. 2 shows a schematic view showing an interlayer tear test of the double-sided adhesive tape.
  • FIG. 2A is a front view
  • FIG. 2B is a side view.
  • a test piece 2 having a size of 50 mm ⁇ 5 mm and two PC plates 1 having a size of 100 mm ⁇ 20 mm and a thickness of 2 mm of double-sided adhesive tape were laminated as shown in FIG. This laminate was crimped with a weight under the conditions of 5 kg and 10 seconds, and then left for 24 hours to prepare a tear test sample in which two PC plates 1 were bonded via a test piece 2.
  • a stainless steel wire 3 (0.3 ⁇ , TRUSCO "TYWS-03" is hooked from under the test piece 2 and 300 mm in the direction of the arrow in FIG. It was pulled under the condition of / min.
  • the test force when the base material layers of the test piece 2 were torn by the wire 3 was measured.
  • the case where the test force was less than 10 N / 5 mm was indicated by ⁇
  • the case where the test force was 10 N / 5 mm or more and less than 15 N / 5 mm was indicated by ⁇
  • the case where the test force was 15 N / 5 mm or more was indicated by ⁇ .
  • FIG. 3 shows a schematic view showing a sample for a tumble test of the double-sided adhesive tape.
  • a frame-shaped test piece 6 having a long side of 23 mm, a short side of 13.3 mm, and a width of 3.2 mm of double-sided adhesive tape, and a PMMA plate 5 having a size of 55 mm x 65 mm, a thickness of 10 mm, and a weight of 42 g, and a size of 70 mm x 130 mm, thickness. It was sandwiched between a SUS plate 4 having a size of 2 mm and a weight of 137 g, and laminated as shown in FIG.
  • This laminate was crimped with a weight under the conditions of 5 kg and 10 seconds, and then left for 24 hours to prepare a sample for tumble test in which the PMMA plate 5 and the SUS plate 4 were bonded to each other via the test piece 6. ..
  • the tumble test sample was placed in a tumble tester (TDR-1000A-SC01 manufactured by Shinei Denshi Keiki Co., Ltd.), and a drop impact from various angles was repeatedly applied at a frequency of 10 drops / min. The number of drops until the double-sided adhesive tape broke and the sample for tumble test was separated was measured. The case where the number of drops was 30 or more was indicated by ⁇ , the case where the number of drops was 10 or more and less than 30 was indicated by 0, and the case where the number of drops was less than 10 was indicated by ⁇ .
  • FIG. 4 shows a schematic view showing a surface waviness test of the double-sided adhesive tape.
  • FIG. 4A is a top view and FIG. 4B is a cross-sectional view.
  • a single-sided black light-shielding tape 8 having a width of 15 mm and a thickness of 50 ⁇ m was laminated on a glass plate 10 having a size of 256 mm ⁇ 182 mm and a thickness of 4 mm at intervals of 15 mm to form a step.
  • a single-sided black light-shielding tape 9 having a width of 15 mm and a thickness of 100 ⁇ m was laminated on the glass plate 10 to form a step.
  • test pieces 7 having a width of 10 mm of double-sided adhesive tape were laminated on the four sides of the glass plate 10.
  • a glass plate 12 having a size of 256 mm ⁇ 182 mm and a thickness of 1 mm was laminated on the test piece 7, and the glass plate 10 and the glass plate 12 were bonded to each other via the test piece 7.
  • a single-sided black light-shielding tape 13 having a thickness of 100 ⁇ m was laminated on the glass plate 12 to obtain a sample for a surface waviness test.
  • a double-sided adhesive tape which is excellent in drop impact resistance, can reduce display unevenness of a display device, and can easily tear a foam base material when peeled from an adherend. can do.

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Abstract

The purpose of the present invention is to provide a double-sided pressure-sensitive adhesive tape which has excellent resistance to impacts by dropping and can reduce display unevenness in display devices and which includes a foam base that is easy to tear for removing from the adherend. This double-sided pressure-sensitive adhesive tape comprises a foam base and pressure-sensitive adhesive layers superposed on both surfaces of the foam base, wherein the foam base has a cell content of 40-75 vol% and a shear breaking strength of 200 N/inch2 to 500 N/inch2.

Description

両面粘着テープDouble-sided adhesive tape
本発明は、両面粘着テープに関する。 The present invention relates to a double-sided adhesive tape.
粘着テープは、電子部品の固定用として広く用いられている。具体的には、例えば、テレビ、モニター等のディスプレイ装置において表面のカバーパネルを筐体に固定するために粘着テープが用いられている。このような粘着テープは、例えば額縁状等の形状で、表示画面の周辺に配置されるようにして用いられる。 Adhesive tapes are widely used for fixing electronic components. Specifically, for example, in a display device such as a television or a monitor, an adhesive tape is used to fix a cover panel on the surface to a housing. Such an adhesive tape is used, for example, in the shape of a frame or the like so as to be arranged around the display screen.
近年、デザインや機能性を追求した結果、テレビ、モニター等のディスプレイ装置は狭額縁化が進み、ベゼルレスなディスプレイ装置への期待も高まっている。従来のディスプレイ装置の製造では、カバーパネルをはめ込みやねじ止めによって筐体に固定することもあったが、狭額縁化の進んだディスプレイ装置でははめ込みやねじ止めが難しいため、粘着テープによる固定にますます需要が高まっており、粘着テープの薄型化及び細幅化も進んでいる。 In recent years, as a result of pursuing design and functionality, display devices such as televisions and monitors have become narrower in frame, and expectations for bezel-less display devices are increasing. In the manufacture of conventional display devices, the cover panel was sometimes fixed to the housing by fitting or screwing, but since it is difficult to fit or screw in a display device with a narrower frame, it is fixed with adhesive tape. Demand is increasing, and adhesive tapes are becoming thinner and narrower.
このようなディスプレイ装置において用いられ得る粘着テープとして、例えば、特許文献１及び２には、基材層の少なくとも片面にアクリル系粘着剤層が積層一体化されており、該基材層が特定の架橋度及び気泡のアスペクト比を有する架橋ポリオレフィン系樹脂発泡シートである衝撃吸収テープが記載されている。 As an adhesive tape that can be used in such a display device, for example, Patent Documents 1 and 2 have an acrylic pressure-sensitive adhesive layer laminated and integrated on at least one surface of a base material layer, and the base material layer is specific. A shock absorbing tape which is a crosslinked polyolefin resin foam sheet having a degree of crosslinking and an aspect ratio of air bubbles is described.
特開２００９－２４２５４１号公報Japanese Unexamined Patent Publication No. 2009-242541 特開２００９－２５８２７４号公報JP-A-2009-258274
しかしながら、テレビ、モニター等のディスプレイ装置は大型化が進んでおり、カバーパネル、筐体等の被固定部材の重量も増加している。このため、粘着テープにはせん断方向に従来以上の非常に大きな荷重がかかり、粘着テープを薄型かつ細幅で用いる場合には特に、輸送時の落下等により衝撃が加わることで基材の層間破壊又は粘着テープの剥がれが発生する問題が生じている。
また、大型化に伴い、ディスプレイ装置には表示ムラも発生しやすくなっている。表示ムラを低減するためには、粘着テープ、特に粘着テープの基材には、応力を解放できる適度な柔軟性が必要とされる。更には、近年、電子部品は高価になる傾向にあるため、例えば部品固定の際に不具合が生じた場合等には、部品をリワークできることが求められている。部品をリワークする方法の１つとして、例えばカッター刃で粘着テープの発泡体基材を引裂き、層間破壊させて部品を取りはずす方法が用いられる。このような場合にも、基材が硬すぎず、適度な柔軟性を有することが求められる。
ここで、輸送時の落下等による衝撃に耐えるためには基材の強度を上げる必要がある一方で、表示ムラの低減及び引裂きやすさのためには基材の柔軟性を上げる必要がある。しかしながら、基材の強度と柔軟性とは相反する性質であるため、これらを両立することは難しい。
本発明は、耐落下衝撃性に優れ、ディスプレイ装置の表示ムラを低減することができ、被着体から剥がす際には発泡体基材を容易に引裂くことができる両面粘着テープを提供することを目的とする。 However, display devices such as televisions and monitors are becoming larger in size, and the weight of fixed members such as cover panels and housings is also increasing. For this reason, a much larger load is applied to the adhesive tape in the shearing direction than before, and especially when the adhesive tape is used in a thin and narrow width, an impact is applied due to dropping during transportation or the like, and the layers of the base material are broken. Alternatively, there is a problem that the adhesive tape is peeled off.
In addition, as the size of the display device increases, display unevenness is likely to occur in the display device. In order to reduce display unevenness, the adhesive tape, particularly the base material of the adhesive tape, is required to have appropriate flexibility to release stress. Furthermore, in recent years, electronic components have tended to be expensive, and therefore, for example, when a problem occurs when fixing a component, it is required to be able to rework the component. As one of the methods for reworking the parts, for example, a method of tearing the foam base material of the adhesive tape with a cutter blade and breaking the layers to remove the parts is used. Even in such a case, it is required that the base material is not too hard and has appropriate flexibility.
Here, while it is necessary to increase the strength of the base material in order to withstand the impact caused by dropping during transportation, it is necessary to increase the flexibility of the base material in order to reduce display unevenness and ease of tearing. However, since the strength and flexibility of the base material are contradictory to each other, it is difficult to achieve both.
The present invention provides a double-sided adhesive tape which is excellent in drop impact resistance, can reduce display unevenness of a display device, and can easily tear a foam base material when peeled from an adherend. With the goal.
本発明は、発泡体基材と、上記発泡体基材の両側に積層された粘着剤層とを有する両面粘着テープであって、上記発泡体基材は、気泡体積分率が４０体積％以上７５体積％以下であり、せん断破断強度が２００Ｎ／ｉｎｃｈ２以上５００Ｎ／ｉｎｃｈ２以下である両面粘着テープである。
以下に本発明を詳述する。 The present invention is a double-sided adhesive tape having a foam base material and pressure-sensitive adhesive layers laminated on both sides of the foam base material, and the foam base material has a bubble volume fraction of 40% by volume or more. and 75% by volume or less, the shear breaking strength of a double-sided pressure-sensitive adhesive tape is 200 N / inch 2 or more 500 N / inch 2 or less.
The present invention will be described in detail below.
本発明者らは、発泡体基材と、該発泡体基材の両側に積層された粘着剤層とを有する両面粘着テープにおいて、Ｘ線ＣＴ（Ｘ－ｒａｙ　Ｃｏｍｐｕｔｅｄ　Ｔｏｍｏｇｒａｐｈｙ；コンピュータ断層撮影法）装置及び画像解析ソフトウェアを用いて発泡体基材の気泡構造を分析し、気泡構造が両面粘着テープの性能に与える影響について検討した。その結果、本発明者らは、発泡体基材の気泡体積分率を特定範囲に調整し、更には発泡体基材のせん断破断強度を特定範囲に調整することで、発泡体基材の強度と柔軟性とをいずれも高めることができることを見出した。これにより、耐落下衝撃性に優れ、ディスプレイ装置の表示ムラを低減することができ、被着体から剥がす際には発泡体基材を容易に引裂くことができる両面粘着テープが得られることを見出し、本発明を完成させるに至った。 The present inventors have an X-ray CT (X-ray Computed Tomography) apparatus in a double-sided adhesive tape having a foam base material and adhesive layers laminated on both sides of the foam base material. The bubble structure of the foam base material was analyzed using image analysis software, and the effect of the bubble structure on the performance of the double-sided adhesive tape was examined. As a result, the present inventors adjust the volume fraction of the foam base material to a specific range, and further adjust the shear breaking strength of the foam base material to a specific range to obtain the strength of the foam base material. And found that both can be increased in flexibility. As a result, it is possible to obtain a double-sided adhesive tape that has excellent drop impact resistance, can reduce display unevenness of the display device, and can easily tear the foam base material when it is peeled off from the adherend. We have found and completed the present invention.
本発明の両面粘着テープは、発泡体基材と、上記発泡体基材の両側に積層された粘着剤層とを有する。
上記発泡体基材は、適度な柔軟性を有するため、応力を解放することができる。上記発泡体基材を有することで、両面粘着テープの応力緩和性が向上する。 The double-sided adhesive tape of the present invention has a foam base material and adhesive layers laminated on both sides of the foam base material.
Since the foam base material has appropriate flexibility, stress can be released. By having the foam base material, the stress relaxation property of the double-sided adhesive tape is improved.
上記発泡体基材は、気泡体積分率の下限が４０体積％、上限が７５体積％である。上記気泡体積分率を上記範囲に調整することで、上記発泡体基材の強度と柔軟性とをいずれも高め、同時に両立することができる。
上記気泡体積分率が４０体積％以上であれば、上記発泡体基材が適度な柔軟性を有することができるため、ディスプレイ装置の表示ムラを低減することができ、両面粘着テープを被着体から剥がす際には容易に上記発泡体基材を引裂くことができる。上記気泡体積分率が７５体積％以下であれば、上記発泡体基材の強度が低下しすぎることを抑制することができるため、両面粘着テープの耐落下衝撃性を向上させることができる。また、上記気泡体積分率が７５体積％以下であれば、上記発泡体基材の防塵性及び防水性も確保されやすい。上記気泡体積分率の好ましい下限は４２体積％、好ましい上限は７０体積％であり、より好ましい下限は４６体積％、より好ましい上限は６７体積％であり、更に好ましい下限は４８体積％、更に好ましい上限は６３体積％であり、特に好ましい下限は５０体積％、特に好ましい上限は６０体積％である。
なお、気泡体積分率は、Ｘ線ＣＴ装置及び画像解析ソフトウェアを用い、下記式（１）により算出する。
気泡体積分率（体積％）＝気泡体積／発泡体基材の体積×１００　　　（１）
式（１）中、気泡体積とは、測定対象試料の発泡体基材に含まれる全ての気泡の体積の合計である。 The foam base material has a lower limit of 40% by volume and an upper limit of 75% by volume of the bubble volume fraction. By adjusting the bubble volume fraction within the above range, both the strength and flexibility of the foam base material can be increased, and at the same time, both can be achieved.
When the bubble volume fraction is 40% by volume or more, the foam base material can have appropriate flexibility, so that display unevenness of the display device can be reduced, and the double-sided adhesive tape is adhered. The foam base material can be easily torn when peeled from. When the bubble volume fraction is 75% by volume or less, it is possible to prevent the strength of the foam base material from being excessively lowered, so that the drop impact resistance of the double-sided adhesive tape can be improved. Further, when the bubble volume fraction is 75% by volume or less, the dustproof property and the waterproof property of the foam base material can be easily ensured. The preferable lower limit of the bubble volume fraction is 42% by volume, the preferable upper limit is 70% by volume, the more preferable lower limit is 46% by volume, the more preferable upper limit is 67% by volume, the further preferable lower limit is 48% by volume, and further preferable. The upper limit is 63% by volume, a particularly preferable lower limit is 50% by volume, and a particularly preferable upper limit is 60% by volume.
The bubble volume fraction is calculated by the following formula (1) using an X-ray CT apparatus and image analysis software.
Bubble volume fraction (volume%) = bubble volume / volume of foam base material x 100 (1)
In the formula (1), the bubble volume is the total volume of all bubbles contained in the foam base material of the sample to be measured.
上記発泡体基材の気泡の長径分布の平均及び標準偏差は特に限定されないが、気泡の長径分布の平均の好ましい上限が５５μｍ、気泡の長径分布の標準偏差の好ましい上限が３０μｍである。
上記長径分布の平均及び標準偏差を上記範囲に調整し、気泡の大きさ及び気泡の大きさのばらつきを一定レベル以下に抑えることで、上記発泡体基材の強度と柔軟性とをいずれも更に高めることができる。その結果、両面粘着テープの耐落下衝撃性を向上させることができ、また、ディスプレイ装置の表示ムラを低減するとともに両面粘着テープを被着体から剥がす際には上記発泡体基材を容易に引裂くことができる。
また、気泡が大きすぎたり気泡の大きさにばらつきがあったりすると、両面粘着テープを薄型かつ細幅で用いる場合には特に、上記発泡体基材において局所的に特に強度の低い箇所が存在することになり、輸送時の落下等により衝撃が加わることで、上記箇所を起点に上記発泡体基材の層間破壊又は両面粘着テープの剥がれが発生する。上記長径分布の平均及び標準偏差を上記範囲に調整し、気泡の大きさ及び気泡の大きさのばらつきを一定レベル以下に抑えることで、局所的に特に強度の低い箇所が存在することを抑制し、両面粘着テープの耐落下衝撃性を向上させることができる。 The average and standard deviation of the major axis distribution of the bubbles of the foam base material are not particularly limited, but the preferable upper limit of the average of the major axis distribution of the bubbles is 55 μm, and the preferable upper limit of the standard deviation of the major axis distribution of the bubbles is 30 μm.
By adjusting the average and standard deviation of the major axis distribution to the above range and suppressing the variation in the size of the bubbles and the size of the bubbles to a certain level or less, the strength and flexibility of the foam base material can be further increased. Can be enhanced. As a result, the drop impact resistance of the double-sided adhesive tape can be improved, the display unevenness of the display device can be reduced, and the foam base material can be easily pulled when the double-sided adhesive tape is peeled off from the adherend. Can be torn.
Further, if the bubbles are too large or the size of the bubbles varies, there are locally particularly low strength points in the foam base material, especially when the double-sided adhesive tape is used in a thin and narrow width. As a result, an impact is applied due to dropping or the like during transportation, so that the above-mentioned location is the starting point for interlayer destruction of the foam base material or peeling of the double-sided adhesive tape. By adjusting the average and standard deviation of the major axis distribution to the above range and suppressing the variation in bubble size and bubble size below a certain level, it is possible to suppress the presence of locally particularly low-intensity areas. , The drop impact resistance of the double-sided adhesive tape can be improved.
上記長径分布の平均のより好ましい上限は５３μｍ、更に好ましい上限は５１μｍ、更により好ましい上限は４９μｍである。上記長径分布の平均の下限は特に限定されず、上記発泡体基材の気泡体積分率及び厚みにも依存して決定されるが、実質的な下限は１０μｍである。
上記長径分布の標準偏差のより好ましい上限は２８μｍ、更に好ましい上限は２７μｍ、更により好ましい上限は２４μｍである。上記長径分布の標準偏差の下限は特に限定されず、小さいほど気泡の大きさにばらつきがなくなるため好ましく、実質的な下限は５μｍである。
なお、気泡の長径分布の平均及び標準偏差は、Ｘ線ＣＴ装置及び画像解析ソフトウェアを用い、気泡の長径分布を求め、得られた長径分布から平均及び標準偏差を算出する。 A more preferable upper limit of the average of the major axis distribution is 53 μm, a further preferable upper limit is 51 μm, and a further preferable upper limit is 49 μm. The lower limit of the average of the major axis distribution is not particularly limited, and is determined depending on the bubble volume fraction and the thickness of the foam base material, but the practical lower limit is 10 μm.
A more preferred upper limit of the standard deviation of the major axis distribution is 28 μm, a further preferred upper limit is 27 μm, and a further preferred upper limit is 24 μm. The lower limit of the standard deviation of the major axis distribution is not particularly limited, and the smaller it is, the more the size of the bubbles does not vary, which is preferable, and the practical lower limit is 5 μm.
For the average and standard deviation of the major axis distribution of bubbles, the major axis distribution of bubbles is obtained using an X-ray CT device and image analysis software, and the average and standard deviation are calculated from the obtained major axis distribution.
上記発泡体基材の気泡の連泡率は特に限定されないが、上記発泡体基材がポリウレタン発泡体である場合、気泡の連泡率の好ましい上限は９５体積％である。一般的に、ポリウレタン発泡体は連泡構造をとり、連泡率は１００体積％に近い値となる。従って、上記発泡体基材がポリウレタン発泡体である場合、上記範囲の連泡率を有することは、ポリウレタン発泡体のなかでは比較的連泡率が低く、独立気泡が多いことを意味する。
上記連泡率を上記範囲に調整し、独立気泡を増やすことで、ポリウレタン発泡体の強度と柔軟性とをいずれも更に高めることができる。その結果、両面粘着テープの耐落下衝撃性を向上させることができ、また、ディスプレイ装置の表示ムラを低減するとともに両面粘着テープを被着体から剥がす際には上記発泡体基材を容易に引裂くことができる。
また、上記連泡率を上記範囲に調整し、独立気泡を増やすことで、上述したような局所的に特に強度の低い箇所が存在することを抑制し、両面粘着テープの耐落下衝撃性を向上させることができる。 The foaming ratio of the bubbles in the foam base material is not particularly limited, but when the foam base material is a polyurethane foam, the preferable upper limit of the foaming ratio of the bubbles is 95% by volume. Generally, the polyurethane foam has a continuous foam structure, and the continuous foam ratio is close to 100% by volume. Therefore, when the foam base material is a polyurethane foam, having a continuous foam ratio in the above range means that the continuous foam ratio is relatively low and the number of closed cells is large among the polyurethane foams.
By adjusting the continuous foam ratio within the above range and increasing the number of closed cells, the strength and flexibility of the polyurethane foam can be further increased. As a result, the drop impact resistance of the double-sided adhesive tape can be improved, the display unevenness of the display device can be reduced, and the foam base material can be easily pulled when the double-sided adhesive tape is peeled off from the adherend. Can be torn.
In addition, by adjusting the continuous foam ratio to the above range and increasing the number of closed cells, it is possible to suppress the presence of locally particularly low-strength areas as described above and improve the drop impact resistance of the double-sided adhesive tape. Can be made to.
上記連泡率のより好ましい上限は９３体積％、更に好ましい上限は９１体積％である。上記連泡率の下限は特に限定されないが、ポリウレタン発泡体の連泡率の一般的な下限は９０体積％である。
なお、気泡の連泡率は、Ｘ線ＣＴ装置及び画像解析ソフトウェアを用い、下記式（２）により算出する。
連泡率（体積％）＝連通気泡体積／気泡体積×１００　　　（２）
式（２）中、連通気泡体積とは、測定対象試料の発泡体基材に含まれる全ての連通した気泡の体積の合計であり、気泡体積とは、測定対象試料の発泡体基材に含まれる全ての気泡の体積の合計である。 A more preferable upper limit of the continuous foam ratio is 93% by volume, and a more preferable upper limit is 91% by volume. The lower limit of the continuous foaming ratio is not particularly limited, but the general lower limit of the continuous foaming ratio of the polyurethane foam is 90% by volume.
The continuous bubble ratio of bubbles is calculated by the following formula (2) using an X-ray CT apparatus and image analysis software.
Communication bubble ratio (volume%) = communication bubble volume / bubble volume x 100 (2)
In the formula (2), the communicating bubble volume is the total volume of all the communicating bubbles contained in the foam base material of the sample to be measured, and the bubble volume is included in the foam base material of the sample to be measured. It is the sum of the volumes of all the bubbles.
上記発泡体基材の気泡の扁平率は特に限定されないが、好ましい上限は０．２である。上記扁平率を上記範囲に調整することで、あらゆる角度からの落下に対する衝撃緩和をより均一にすることができ、両面粘着テープの耐落下衝撃性を向上させることができる。 The flatness of the bubbles in the foam base material is not particularly limited, but the preferable upper limit is 0.2. By adjusting the flatness to the above range, the impact mitigation against dropping from any angle can be made more uniform, and the drop impact resistance of the double-sided adhesive tape can be improved.
上記扁平率のより好ましい上限は０．１８、更に好ましい上限は０．１６、更により好ましい上限は０．１４である。上記扁平率の下限は特に限定されず、０に近づくほど気泡が真球に近づき、あらゆる角度からの落下に対する衝撃緩和がより均一となるため好ましく、実質的な下限は０．０５である。 The more preferable upper limit of the flatness is 0.18, the further preferable upper limit is 0.16, and the even more preferable upper limit is 0.14. The lower limit of the flatness is not particularly limited, and the closer it is to 0, the closer the bubbles are to a true sphere, and the more uniform the impact relaxation against dropping from all angles is preferable. Therefore, the practical lower limit is 0.05.
上記発泡体基材の気泡のアスペクト比は特に限定されないが、好ましい上限は１．５である。上記アスペクト比を上記範囲に調整することで、あらゆる角度からの落下に対する衝撃緩和をより均一にすることができ、両面粘着テープの耐落下衝撃性を向上させることができる。 The aspect ratio of the bubbles in the foam base material is not particularly limited, but the preferable upper limit is 1.5. By adjusting the aspect ratio to the above range, the impact mitigation against dropping from any angle can be made more uniform, and the drop impact resistance of the double-sided adhesive tape can be improved.
上記アスペクト比のより好ましい上限は１．１、更に好ましい上限は１．０９、更により好ましい上限は１．０７である。上記アスペクト比の下限は特に限定されず、１に近づくほど気泡が真円に近づき、あらゆる角度からの落下に対する衝撃緩和がより均一となるため好ましく、実質的な下限は１．０１である。
なお、気泡のアスペクト比及び扁平率は、Ｘ線ＣＴ装置及び画像解析ソフトウェアを用い、下記式（３）及び（４）により算出する。
アスペクト比＝ｘ／ｙ　　　（３）
扁平率＝｛（ｘ＋ｙ）／２－ｚ｝／ｚ　　（４）
（ｘ＝長径、ｙ＝中径、ｚ＝短径、ｘ≧ｙ≧ｚ） A more preferable upper limit of the aspect ratio is 1.1, a further preferable upper limit is 1.09, and a further preferable upper limit is 1.07. The lower limit of the aspect ratio is not particularly limited, and the closer it is to 1, the closer the bubbles are to a perfect circle, and the more uniform the impact relaxation against dropping from all angles is preferable. Therefore, the practical lower limit is 1.01.
The aspect ratio and flatness of the bubbles are calculated by the following equations (3) and (4) using an X-ray CT apparatus and image analysis software.
Aspect ratio = x / y (3)
Flattening = {(x + y) /2-z} / z (4)
(X = major diameter, y = medium diameter, z = minor diameter, x ≧ y ≧ z)
上記Ｘ線ＣＴ装置及び上記画像解析ソフトウェアは特に限定されないが、上記Ｘ線ＣＴ装置及び上記画像解析ソフトウェアを用いた分析は、より詳細には、例えば、以下のようにして行われる。
発泡体基材を切断して得た測定サンプルの中心部を、Ｘ線ＣＴ装置（例えば、ヤマト科学社製、「ＴＤＭ１０００Ｈ－ＩＩ（２Ｋ）」、解像度１．５μｍ／１ピクセル程度）により撮像し、長さ１．５ｍｍ、幅１．２ｍｍ、高さ０．３ｍｍの直方体状３Ｄ画像を得る。得られた画像について、画像解析ソフトウェア（例えば、ＦＥＩ社製、「Ａｖｉｚｏ９．２．０」）によりノイズ除去及び二値化を行い、発泡体基材の気泡構造を表す各数値（気泡体積分率、気泡の長径分布の平均及び標準偏差、気泡の連泡率、気泡のアスペクト比及び気泡の扁平率等）を求める。Ｘ線源としては、Ｍｏを用い、レンズ（Ｌ０２７０）を用いて、ビニング２、露光時間１０秒、撮影枚数１２００枚の条件で撮影を行う。
画像解析の際には、まずＭｅｄｉａｎ　Ｆｉｌｔｅｒ（Ｎｅｉｇｈｂｏｒｈｏｏｄ値　２６）機能によりノイズを除去する。その後、Ｉｎｔｅｒａｃｔｉｖｅ　Ｔｈｒｅｓｈｏｌｄｉｎｇ機能で二値化を行う。閾値は２５６階調のうち９０とする。二値化後の画像において、気泡が独立気泡か連泡であるかは、画素の連続部分の途切れの有無によって判断する。また、長径、中径、短径の算出にあたっては、まず気泡同士を接点で分割し、気泡の重心を求める。次いで、当該重心と同じ位置に重心を持ち、かつ、気泡に内接する直方体を設定し、直交する３辺の長さについて長い方からそれぞれ長径、中径、短径とする。なおこのとき、長径が１０μｍ未満の気泡は除外する。 The X-ray CT apparatus and the image analysis software are not particularly limited, but the analysis using the X-ray CT apparatus and the image analysis software is performed in more detail, for example, as follows.
The central part of the measurement sample obtained by cutting the foam substrate was imaged with an X-ray CT device (for example, "TDM1000H-II (2K)" manufactured by Yamato Scientific Co., Ltd., resolution of about 1.5 μm / pixel). A rectangular parallelepiped 3D image having a length of 1.5 mm, a width of 1.2 mm, and a height of 0.3 mm is obtained. The obtained image is noise-removed and binarized by image analysis software (for example, "Avizo 9.2.0" manufactured by FEI), and each numerical value (foam volume fraction) representing the bubble structure of the foam base material is used. , Average and standard deviation of the major axis distribution of bubbles, continuous bubble rate of bubbles, aspect ratio of bubbles, flatness of bubbles, etc.). As an X-ray source, Mo is used, and a lens (L0270) is used to take a picture under the conditions of binning 2, an exposure time of 10 seconds, and the number of shots of 1200.
At the time of image analysis, noise is first removed by the Median Filter (Neighborhood value 26) function. After that, binarization is performed by the Interactive Thresholding function. The threshold value is 90 out of 256 gradations. In the binarized image, whether the bubble is a closed bubble or a continuous bubble is determined by the presence or absence of a break in the continuous portion of the pixel. In calculating the major diameter, medium diameter, and minor diameter, the bubbles are first divided by contacts to obtain the center of gravity of the bubbles. Next, a rectangular parallelepiped having the center of gravity at the same position as the center of gravity and inscribed in the bubble is set, and the lengths of the three orthogonal sides are set to the major axis, the medium diameter, and the minor axis, respectively, from the longest. At this time, bubbles having a major axis of less than 10 μm are excluded.
上記発泡体基材の気泡構造を表す各数値（気泡体積分率、気泡の長径分布の平均及び標準偏差、気泡の連泡率、気泡のアスペクト比及び気泡の扁平率等）を上記範囲に調整する方法は特に限定されない。
例えば、上記発泡体基材がポリウレタン発泡体である場合、ウレタン樹脂組成物におけるポリイソシアネート及びポリオールの種類及び含有量、ウレタン樹脂組成物に空気、窒素等を混合する際の条件、ウレタン樹脂組成物を加熱硬化させる際の反応条件等を調整すればよい。なかでも、例えばウレタン樹脂組成物におけるポリイソシアネートの含有量を増やして樹脂の流動性を高める等によってウレタン化反応を緩やかに進めることにより、より均一な大きさの気泡を生成させて気泡構造を調整する方法が好ましい。
より具体的には、上記気泡体積分率は、ウレタン樹脂組成物におけるポリイソシアネート及びポリオールの種類及び含有量、並びに、発泡条件を変化させることで調整することができる。原料が同じ場合であっても、ウレタン樹脂組成物に空気、窒素等を混合する際の条件、ウレタン樹脂組成物を加熱硬化させる際の反応条件等を変化させることで調整することができる。また、上記気泡の長径分布の平均及び標準偏差は、ウレタン化反応を緩やかに進めることにより調整することで小さくすることができる。 Adjust each numerical value representing the bubble structure of the foam base material (volume fraction of bubbles, average and standard deviation of major axis distribution of bubbles, continuous bubble rate of bubbles, aspect ratio of bubbles, flatness of bubbles, etc.) within the above range. The method of doing so is not particularly limited.
For example, when the foam base material is a polyurethane foam, the type and content of polyisocyanate and polyol in the urethane resin composition, the conditions for mixing air, nitrogen, etc. with the urethane resin composition, and the urethane resin composition. The reaction conditions and the like when the urethane is heat-cured may be adjusted. Among them, for example, by increasing the content of polyisocyanate in the urethane resin composition to increase the fluidity of the resin and gradually advancing the urethanization reaction, bubbles of a more uniform size are generated to adjust the bubble structure. The method of doing so is preferable.
More specifically, the bubble volume fraction can be adjusted by changing the type and content of polyisocyanate and polyol in the urethane resin composition, and the foaming conditions. Even when the raw materials are the same, it can be adjusted by changing the conditions for mixing air, nitrogen, etc. with the urethane resin composition, the reaction conditions for heating and curing the urethane resin composition, and the like. Further, the average and standard deviation of the major axis distribution of the bubbles can be reduced by adjusting by slowly advancing the urethanization reaction.
上記発泡体基材は、単層構造であっても多層構造であってもよい。
上記発泡体基材は特に限定されず、例えば、ポリウレタン発泡体、ポリオレフィン発泡体、アクリル発泡体等が挙げられる。なかでも、適度な柔軟性を有し、気泡構造を調整しやすいことから、ポリウレタン発泡体が好ましい。 The foam base material may have a single-layer structure or a multi-layer structure.
The foam base material is not particularly limited, and examples thereof include polyurethane foams, polyolefin foams, and acrylic foams. Of these, polyurethane foam is preferable because it has appropriate flexibility and the bubble structure can be easily adjusted.
上記ポリウレタン発泡体として、例えば、ポリイソシアネート及びポリオールを含有するウレタン樹脂組成物からなるポリウレタン発泡体が挙げられる。このようなポリウレタン発泡体は、上記ウレタン樹脂組成物を加熱硬化させることにより製造することができる。
上記ポリイソシアネートは特に限定されず、一般的なポリウレタン発泡体に用いられる芳香族ポリイソシアネート又は脂肪族ポリイソシアネートが挙げられる。なかでも、１分子中にイソシアネート基を２つ有する芳香族ジイソシアネート又は脂肪族ジイソシアネートが好ましい。 Examples of the polyurethane foam include a polyurethane foam made of a urethane resin composition containing a polyisocyanate and a polyol. Such a polyurethane foam can be produced by heat-curing the urethane resin composition.
The polyisocyanate is not particularly limited, and examples thereof include aromatic polyisocyanates and aliphatic polyisocyanates used for general polyurethane foams. Of these, aromatic diisocyanates or aliphatic diisocyanates having two isocyanate groups in one molecule are preferable.
上記ポリイソシアネートが上記芳香族ジイソシアネート又は脂肪族ジイソシアネートであることにより、上記ポリウレタン発泡体の架橋度が上がりすぎず、ガラス転移点（Ｔｇ）が比較的低くなるため、伸びやすい発泡体となって強度と柔軟性とが高くなる。
上記芳香族ジイソシアネート又は脂肪族ジイソシアネートとして、具体的には例えば、４，４’－ジフェニルメタンジイソシアネート、トリレンジイソシアネート、１，６－ヘキサメチレンジイソシアネート、１，５－ナフタレンジイソシアネート、パラフェニレンジイソシアネート、２，２，４－トリメチルヘキサメチレンジイソシアネート、２，４，４－トリメチルヘキサメチレンジイソシアネート、４，４’－ジシクロヘキシルメタンジイソシアネート、ｍ－キシ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、水素添加ＭＤＩ、イソホロンジイソシアネート等が挙げられる。なお、４，４’－ジフェニルメタンジイソシアネートは、一般に「ＭＤＩ」又は「２核体モノメリックＭＤＩ」とも呼ばれる。なかでも、柔軟性に優れるポリウレタン発泡体が得られやすいことから、４，４’－ジフェニルメタンジイソシアネート（ＭＤＩ）が好ましい。これらの芳香族ジイソシアネート又は脂肪族ジイソシアネートは単独で用いてもよいし、２種以上を併用してもよい。 Since the polyisocyanate is the aromatic diisocyanate or the aliphatic diisocyanate, the degree of cross-linking of the polyurethane foam does not increase too much and the glass transition point (Tg) becomes relatively low, so that the foam becomes easily stretchable and has strength. And flexibility is high.
Specific examples of the aromatic diisocyanate or aliphatic diisocyanate include 4,4'-diphenylmethane diisocyanate, tolylene diisocyanate, 1,6-hexamethylene diisocyanate, 1,5-naphthalenediocyanate, paraphenylenediocyanate, 2,2. , 4-trimethylhexamethylene diisocyanate, 2,4,4-trimethylhexamethylene diisocyanate, 4,4'-dicyclohexylmethane diisocyanate, m-xylene diisocyanate, hexamethylene diisocyanate, hydrogenated MDI, isophorone diisocyanate and the like. The 4,4'-diphenylmethane diisocyanate is also generally referred to as "MDI" or "binuclear monomeric MDI". Of these, 4,4'-diphenylmethane diisocyanate (MDI) is preferable because a polyurethane foam having excellent flexibility can be easily obtained. These aromatic diisocyanates or aliphatic diisocyanates may be used alone or in combination of two or more.
上記ポリイソシアネートは、１分子中にイソシアネート基を３つ以上有していてもよい。このようなポリイソシアネートとして、例えば、ポリメリックＭＤＩ等が挙げられる。上記ポリイソシアネートとして、更に、イソシアネート基を有するウレタンプレポリマー等も挙げられる。これらのポリイソシアネートは単独で用いてもよいし、２種以上を併用してもよい。 The polyisocyanate may have three or more isocyanate groups in one molecule. Examples of such a polyisocyanate include polyvinyl MDI and the like. Further, as the polyisocyanate, a urethane prepolymer having an isocyanate group and the like can be mentioned. These polyisocyanates may be used alone or in combination of two or more.
上記ポリオールは特に限定されず、一般的なポリウレタン発泡体に用いられるポリオールが挙げられる。具体的には例えば、ポリエーテルポリオール、ポリエステルポリオール、ポリエーテルエステルポリオール等が挙げられる。また、上記ポリオールとして、３官能ポリエーテルポリオール、グリセリン、トリメチロールプロパン等も挙げられる。これらのポリオールは単独で用いてもよいし、２種以上を併用してもよい。
上記ポリエーテルポリオールは特に限定されず、例えば、ポリプロピレングリコール（ＰＰＧ）等が挙げられる。上記ポリエステルポリオールは特に限定されず、ポリオール成分と、酸成分とからなるポリエステルポリオールを用いることができる。 The above-mentioned polyol is not particularly limited, and examples thereof include polyols used for general polyurethane foams. Specific examples thereof include polyether polyols, polyester polyols, and polyether ester polyols. Further, examples of the above-mentioned polyol include trifunctional polyether polyol, glycerin, trimethylolpropane and the like. These polyols may be used alone or in combination of two or more.
The above-mentioned polyether polyol is not particularly limited, and examples thereof include polypropylene glycol (PPG) and the like. The polyester polyol is not particularly limited, and a polyester polyol composed of a polyol component and an acid component can be used.
上記ポリオールは、短鎖ジオールを含有することが好ましい。
上記ポリオールが上記短鎖ジオールを含有することにより、上記ポリウレタン発泡体の強度が高くなる。このため、より均一な大きさの気泡を生成させて気泡構造を調整するために例えば上記ウレタン樹脂組成物における上記ポリイソシアネートの含有量を増やして樹脂の流動性を高める等によってウレタン化反応を緩やかに進める場合にも、上記ポリウレタン発泡体の強度が低下しすぎることを抑制することができる。
上記短鎖ジオールとして、例えば、１，５－ペンタンジオール、１，６－ヘキサメチレンジオール、ネオペンチルグリコール、エチレングリコール、ジエチレングリコール、プロピレングリコール、ジプロピレングリコール、１，４－ブタンジオール、ネオペンチルグリコール等が挙げられる。これらの短鎖ジオールは単独で用いてもよいし、２種以上を併用してもよい。なかでも、高強度のポリウレタン発泡体が得られやすいことから、１，５－ペンタンジオール又は１，６－ヘキサメチレンジオールが好ましい。また、上記連泡率を低くしやすいことから、ネオペンチルグリコールが好ましい。 The polyol preferably contains a short chain diol.
When the polyol contains the short chain diol, the strength of the polyurethane foam is increased. Therefore, in order to generate bubbles having a more uniform size and adjust the bubble structure, for example, the urethanization reaction is slowed down by increasing the content of the polyisocyanate in the urethane resin composition to increase the fluidity of the resin. Even in the case of proceeding to the above, it is possible to prevent the polyurethane foam from being excessively lowered in strength.
Examples of the short chain diol include 1,5-pentanediol, 1,6-hexamethylene diol, neopentyl glycol, ethylene glycol, diethylene glycol, propylene glycol, dipropylene glycol, 1,4-butanediol, neopentyl glycol and the like. Can be mentioned. These short chain diols may be used alone or in combination of two or more. Of these, 1,5-pentanediol or 1,6-hexamethylenediol is preferable because a high-strength polyurethane foam can be easily obtained. In addition, neopentyl glycol is preferable because it is easy to lower the continuous foam ratio.
上記ポリオールの重量平均分子量は特に限定されないが、好ましい下限は５００、好ましい上限は５０００である。上記ポリオールの重量平均分子量が５００以上であれば、上記ポリウレタン発泡体が適度な柔軟性を有することができる。上記ポリオールの重量平均分子量が５０００以下であれば、上記ポリウレタン発泡体の強度が低下しすぎることを抑制することができる。上記ポリオールの重量平均分子量のより好ましい下限は７００、より好ましい上限は２０００であり、更に好ましい下限は８００、更に好ましい上限は１５００である。
なお、ポリオールの重量平均分子量は、例えば、試料のテトラヒドロフラン溶液を調製後、ＧＰＣ装置（例えば、東ソー社製、製品名「ＨＬＣ－８２２０」、カラム：ＴＳＫｇｅｌＳｕｒｐｅｒ　ＨＺＭ－Ｎ（４本））を用いて測定することができる。ＧＰＣ測定では、測定条件として、例えば、４０℃、流量０．５ｍＬ／ｍｉｎを採用することができる。 The weight average molecular weight of the polyol is not particularly limited, but the preferred lower limit is 500 and the preferred upper limit is 5000. When the weight average molecular weight of the polyol is 500 or more, the polyurethane foam can have appropriate flexibility. When the weight average molecular weight of the polyol is 5000 or less, it is possible to prevent the strength of the polyurethane foam from being excessively lowered. The more preferable lower limit of the weight average molecular weight of the polyol is 700, the more preferable upper limit is 2000, the more preferable lower limit is 800, and the further preferable upper limit is 1500.
For the weight average molecular weight of the polyol, for example, after preparing a tetrahydrofuran solution of the sample, a GPC apparatus (for example, manufactured by Tosoh Corporation, product name "HLC-8220", column: TSKgelSuper HZM-N (4 pieces)) was used. Can be measured. In the GPC measurement, for example, 40 ° C. and a flow rate of 0.5 mL / min can be adopted as the measurement conditions.
上記ウレタン樹脂組成物における上記ポリイソシアネートのイソシアネートインデックスは特に限定されないが、好ましい下限は７０、好ましい上限は１２０である。
イソシアネートインデックスとは、イソシアネートと活性水素含有化合物との反応におけるイソシアネート当量に関する指数である。イソシアネートインデックスが１００未満の場合には水酸基等の反応基がイソシアネート基より過剰であり、イソシアネートインデックスが１００を超える場合にはイソシアネート基が水酸基等の反応基より過剰であることを意味する。
上記イソシアネートインデックスが７０以上であれば、上記ポリイソシアネートによる架橋が充分となり、気泡構造を調整しやすくなるため、上記ポリウレタン発泡体が適度な密度を有することができ、強度と柔軟性とが高くなる。上記イソシアネートインデックスが１２０以下であれば、上記ポリウレタン発泡体の架橋度が上がりすぎず、ガラス転移点（Ｔｇ）が比較的低くなるため、伸びやすい発泡体となって強度と柔軟性とが高くなる。 The isocyanate index of the polyisocyanate in the urethane resin composition is not particularly limited, but a preferable lower limit is 70 and a preferable upper limit is 120.
The isocyanate index is an index relating to the isocyanate equivalent in the reaction between isocyanate and an active hydrogen-containing compound. When the isocyanate index is less than 100, it means that the reactive group such as a hydroxyl group is more than the isocyanate group, and when the isocyanate index is more than 100, it means that the isocyanate group is more than the reactive group such as the hydroxyl group.
When the isocyanate index is 70 or more, the cross-linking with the polyisocyanate is sufficient and the bubble structure can be easily adjusted. Therefore, the polyurethane foam can have an appropriate density, and the strength and flexibility are increased. .. When the isocyanate index is 120 or less, the degree of cross-linking of the polyurethane foam does not increase too much, and the glass transition point (Tg) becomes relatively low, so that the foam becomes easily stretchable and has high strength and flexibility. ..
上記ウレタン樹脂組成物における上記ポリイソシアネートの含有量は特に限定されないが、例えば上記ウレタン樹脂組成物における上記ポリイソシアネートの含有量を増やして樹脂の流動性を高める等によってウレタン化反応を緩やかに進めることにより、より均一な大きさの気泡を生成させて気泡構造を調整することが好ましい。
上記ポリイソシアネートの含有量は、上記ポリオール１００重量％に対する好ましい下限が５重量％、好ましい上限が３０重量％である。上記ポリイソシアネートの含有量が５重量％以上であれば、ウレタン化反応を緩やかに進めてより均一な大きさの気泡を生成させることができるため、気泡構造を調整しやすくなり、上記ポリウレタン発泡体の強度と柔軟性とが高くなる。上記ポリイソシアネートの含有量が３０重量％以下であれば、上記ポリウレタン発泡体の架橋度が上がりすぎず、ガラス転移点（Ｔｇ）が比較的低くなるため、伸びやすい発泡体となって強度と柔軟性とが高くなる。上記ポリイソシアネートの含有量のより好ましい下限は１５重量％、より好ましい上限は２５重量％である。 The content of the polyisocyanate in the urethane resin composition is not particularly limited, but the urethanization reaction is slowly promoted by, for example, increasing the content of the polyisocyanate in the urethane resin composition to increase the fluidity of the resin. Therefore, it is preferable to adjust the bubble structure by generating bubbles having a more uniform size.
Regarding the content of the polyisocyanate, the preferable lower limit is 5% by weight and the preferable upper limit is 30% by weight with respect to 100% by weight of the polyol. When the content of the polyisocyanate is 5% by weight or more, the urethanization reaction can be slowly promoted to generate bubbles having a more uniform size, so that the bubble structure can be easily adjusted and the polyurethane foam can be easily adjusted. Increases strength and flexibility. When the content of the polyisocyanate is 30% by weight or less, the degree of cross-linking of the polyurethane foam does not increase too much and the glass transition point (Tg) becomes relatively low, so that the foam becomes stretchable and has strength and flexibility. The sex becomes high. The more preferable lower limit of the content of the polyisocyanate is 15% by weight, and the more preferable upper limit is 25% by weight.
上記ウレタン樹脂組成物は、必要に応じて、触媒を含有してもよい。
上記触媒として、例えば、有機錫化合物、有機亜鉛化合物、有機ニッケル化合物、有機鉄化合物、金属触媒、３級アミン系触媒、有機酸塩等が挙げられる。なかでも、有機錫化合物が好ましい。これらの触媒は単独で用いてもよいし、２種以上を併用してもよい。
上記触媒の添加量は特に限定されないが、上記ポリオール１００重量部に対する好ましい下限が０．０５重量部、好ましい上限が５．０重量部、より好ましい上限は４．０重量部である。 The urethane resin composition may contain a catalyst, if necessary.
Examples of the catalyst include organic tin compounds, organic zinc compounds, organic nickel compounds, organic iron compounds, metal catalysts, tertiary amine-based catalysts, and organic acid salts. Of these, organic tin compounds are preferable. These catalysts may be used alone or in combination of two or more.
The amount of the catalyst added is not particularly limited, but the preferable lower limit is 0.05 parts by weight, the preferable upper limit is 5.0 parts by weight, and the more preferable upper limit is 4.0 parts by weight with respect to 100 parts by weight of the polyol.
上記有機錫化合物として、例えば、スタナスオクトエート、ジブチルチンジアセテート、ジブチルチンジラウレート等が挙げられる。上記有機亜鉛化合物として、例えば、オクチル酸亜鉛等が挙げられる。上記有機ニッケル化合物として、例えば、ニッケルアセチルアセトエート、ニッケルジアセチルアセトエート等が挙げられる。上記有機鉄化合物として、例えば、鉄アセチルアセトエート等が挙げられる。上記金属触媒として、例えば、酢酸ナトリウム等のアルカリ金属又はアルカリ土類金属のアルコキシド、フェノキシド等が挙げられる。上記３級アミン系触媒として、例えば、トリエチルアミン、トリエチレンジアミン、Ｎ－メチルモルホリンジメチルアミノメチルフェノール、イミダゾール、１，８－ジアザビシクロ［５．４．０］ウンデセン等が挙げられる。 Examples of the organic tin compound include stanas octoate, dibutyltin diacetate, dibutyltin dilaurate and the like. Examples of the organic zinc compound include zinc octylate and the like. Examples of the organic nickel compound include nickel acetylacetone and nickel diacetylacetone. Examples of the organic iron compound include iron acetylacetone. Examples of the metal catalyst include alkoxides and phenoxides of alkali metals such as sodium acetate or alkaline earth metals. Examples of the tertiary amine-based catalyst include triethylamine, triethylenediamine, N-methylmorpholine dimethylaminomethylphenol, imidazole, 1,8-diazabicyclo [5.4.0] undecene and the like.
上記ウレタン樹脂組成物は、必要に応じて、発泡剤を含有してもよい。
上記発泡剤として、一般的なポリウレタン発泡体に用いられる発泡剤が挙げられる。具体的には例えば、水、ペンタン、シクロペンタン、ヘキサン、シクロヘキサン、ジクロロメタン、炭酸ガス等が挙げられる。
上記発泡剤の添加量は特に限定されず、適宜の量とされるが、上記発泡剤が水である場合には、通常、上記ポリオール１００重量部に対して０．１～３重量部程度である。 The urethane resin composition may contain a foaming agent, if necessary.
Examples of the foaming agent include foaming agents used for general polyurethane foams. Specific examples thereof include water, pentane, cyclopentane, hexane, cyclohexane, dichloromethane, carbon dioxide and the like.
The amount of the foaming agent added is not particularly limited and may be an appropriate amount, but when the foaming agent is water, it is usually about 0.1 to 3 parts by weight with respect to 100 parts by weight of the polyol. is there.
上記ウレタン樹脂組成物は、必要に応じて、整泡剤を含有してもよい。
上記整泡剤として、例えば、ジメチルシロキサン、ポリエーテルジメチルシロキサン、フェニルメチルシロキサン等のシリコーン系整泡剤が挙げられる。なかでも、ポリエーテルジメチルシロキサンが好ましい。ポリエーテルジメチルシロキサンのなかでも、ジメチルポリシロキサンとポリエーテルとのブロック共重合体がより好ましい。これらの整泡剤は単独で用いてもよいし、２種以上を併用してもよい。
上記整泡剤の添加量は特に限定されないが、上記ポリオール１００重量部に対する好ましい下限は０．２重量部、好ましい上限は７重量部であり、より好ましい下限は０．４重量部、より好ましい上限は５重量部である。 The urethane resin composition may contain a defoaming agent, if necessary.
Examples of the defoaming agent include silicone-based defoaming agents such as dimethylsiloxane, polyetherdimethylsiloxane, and phenylmethylsiloxane. Of these, polyetherdimethylsiloxane is preferable. Among the polyether dimethylsiloxanes, block copolymers of dimethylpolysiloxane and polyether are more preferable. These foam stabilizers may be used alone or in combination of two or more.
The amount of the foam stabilizer added is not particularly limited, but the preferable lower limit with respect to 100 parts by weight of the polyol is 0.2 parts by weight, the preferable upper limit is 7 parts by weight, the more preferable lower limit is 0.4 parts by weight, and the more preferable upper limit. Is 5 parts by weight.
上記ウレタン樹脂組成物は、必要に応じて、紫外線吸収剤、酸化防止剤、有機充填剤、無機充填剤、着色剤等のポリウレタン発泡体の製造において一般的に用いられる添加剤を含有してもよい。 If necessary, the urethane resin composition may contain additives generally used in the production of polyurethane foams such as ultraviolet absorbers, antioxidants, organic fillers, inorganic fillers, and colorants. Good.
上記ポリウレタン発泡体を製造する方法として、例えば、空気、窒素等を機械的に混合し泡立てたウレタン樹脂組成物（液体）を離型ライナー又は樹脂フィルムの表面に塗布し、塗布したウレタン樹脂組成物を加熱硬化させることによって発泡体を製造する方法（メカニカルフロス法）等が挙げられる。また、上記ポリウレタン発泡体を形成するための原料に、上記ポリイソシアネートを反応させガスを発生させる方法（化学的発泡法）等が挙げられる。なかでも、メカニカルフロス法が好ましい。メカニカルフロス法により得られたポリウレタン発泡体は、化学的発泡法により得られたポリウレタン発泡体と比べて高密度となりやすく、かつ、気泡構造が微細で均一になりやすい。 As a method for producing the polyurethane foam, for example, a urethane resin composition (liquid) obtained by mechanically mixing air, nitrogen, etc. and foaming is applied to the surface of a release liner or a resin film, and the applied urethane resin composition is applied. A method of producing a foam by heat-curing the resin (mechanical floss method) and the like can be mentioned. Further, a method of reacting the polyisocyanate with the raw material for forming the polyurethane foam to generate a gas (chemical foaming method) and the like can be mentioned. Of these, the mechanical floss method is preferable. The polyurethane foam obtained by the mechanical floss method tends to have a higher density than the polyurethane foam obtained by the chemical foam method, and the bubble structure tends to be fine and uniform.
上記ポリオレフィン発泡体として、例えば、ポリエチレン系樹脂、ポリプロピレン系樹脂、ポリブタジエン系樹脂等の樹脂からなる発泡体が挙げられる。なかでも、柔軟なポリオレフィン発泡体が得られやすいことから、ポリエチレン系樹脂が好ましい。 Examples of the polyolefin foam include a foam made of a resin such as a polyethylene resin, a polypropylene resin, and a polybutadiene resin. Of these, polyethylene-based resins are preferable because flexible polyolefin foams can be easily obtained.
上記発泡体基材は、せん断破断強度の下限が２００Ｎ／ｉｎｃｈ２、上限が５００Ｎ／ｉｎｃｈ２である。上記せん断破断強度が２００Ｎ／ｉｎｃｈ２以上であれば、上記発泡体基材の強度が充分に高くなり、両面粘着テープの耐落下衝撃性が向上する。上記せん断破断強度が５００Ｎ／ｉｎｃｈ２以下であれば、上記発泡体基材の柔軟性が低下しすぎることを抑制することができるため、ディスプレイ装置の表示ムラを低減することができ、両面粘着テープを被着体から剥がす際には容易に上記発泡体基材を引裂くことができる。上記せん断破断強度の好ましい下限は２２０Ｎ／ｉｎｃｈ２、好ましい上限は４７０Ｎ／ｉｎｃｈ２であり、より好ましい下限は２４０Ｎ／ｉｎｃｈ２、より好ましい上限は４５０Ｎ／ｉｎｃｈ２であり、更に好ましい下限は２７０Ｎ／ｉｎｃｈ２、より好ましい上限は４１５Ｎ／ｉｎｃｈ２である。 The foam substrate has a lower limit of shear breaking strength of 200 N / inch 2 and an upper limit of 500 N / inch 2 . When the shear breaking strength is 200 N / inch 2 or more, the strength of the foam base material is sufficiently high, and the drop impact resistance of the double-sided adhesive tape is improved. When the shear breaking strength is 500 N / inch 2 or less, it is possible to suppress the flexibility of the foam base material from being excessively lowered, so that display unevenness of the display device can be reduced, and the double-sided adhesive tape can be used. The foam base material can be easily torn when the material is peeled off from the adherend. The preferred lower limit of the shear breaking strength 220 N / inch 2, a preferred upper limit is 470N / inch 2, and more preferable lower limit is 240 N / inch 2, and more preferred upper limit is 450 N / inch 2, still more preferred lower limit 270N / inch 2. A more preferable upper limit is 415 N / inch 2 .
なお、せん断破断強度は、以下の方法により測定できる。
図１に、せん断破断強度の測定方法を示す模式図を示す。まず、両面粘着テープのサイズ２５ｍｍ×２５ｍｍの試験片１８、及び、２枚のサイズ１２５ｍｍ×５０ｍｍ、厚み２ｍｍのＳＵＳ板１９を図１に示すように積層する。この積層体を５ｋｇ、１０秒の条件で重しを用いて圧着した後、２４時間静置し、試験片１８を介して２枚のＳＵＳ板１９を貼り合わせた試験用サンプルを作製する。この試験用サンプルの一方のＳＵＳ板１９を固定した後、２３℃の条件下、他方のＳＵＳ板１９の上方一方を、ＳＵＳ板の積層方向と垂直な方向（図中、矢印方向）に１２．７ｍｍ／ｍｉｎの条件で引っ張り、試験片１８が破断するときに試験片１８にかかる力（破断点強度）を測定する。なお、試験片１８が破断するとは、発泡体基材が層間破壊することを意味する。
上記発泡体基材のせん断破断強度は、ウレタン樹脂組成物におけるポリイソシアネート及びポリオールの種類及び含有量を変化させることで調整することができる。原料が同じ場合であっても、気泡体積分率、気泡の長径分布の平均及び標準偏差等を適切な範囲に設定することで調整することができる。 The shear breaking strength can be measured by the following method.
FIG. 1 shows a schematic diagram showing a method for measuring shear breaking strength. First, a test piece 18 having a size of 25 mm × 25 mm and two SUS plates 19 having a size of 125 mm × 50 mm and a thickness of 2 mm of double-sided adhesive tape are laminated as shown in FIG. This laminate is crimped with a weight under the conditions of 5 kg and 10 seconds, and then allowed to stand for 24 hours to prepare a test sample in which two SUS plates 19 are bonded via a test piece 18. After fixing one of the SUS plates 19 of this test sample, under the condition of 23 ° C., the upper one of the other SUS plates 19 is placed in the direction perpendicular to the stacking direction of the SUS plates (in the figure, the arrow direction). It is pulled under the condition of 7 mm / min, and the force (breaking point strength) applied to the test piece 18 when the test piece 18 breaks is measured. In addition, when the test piece 18 breaks, it means that the foam base material breaks between layers.
The shear breaking strength of the foam base material can be adjusted by changing the type and content of the polyisocyanate and the polyol in the urethane resin composition. Even when the raw materials are the same, it can be adjusted by setting the volume fraction of bubbles, the average of the major axis distribution of bubbles, the standard deviation, and the like within appropriate ranges.
上記発泡体基材の２５％圧縮強度は特に限定されないが、好ましい下限は０．０１５ＭＰａ、好ましい上限は０．０８ＭＰａである。上記２５％圧縮強度が０．０１５ＭＰａ以上であれば、上記発泡体基材の強度が充分に高くなり、両面粘着テープの耐落下衝撃性が向上する。上記２５％圧縮強度が０．０８ＭＰａ以下であれば、上記発泡体基材の柔軟性が低下しすぎることを抑制することができるため、両面粘着テープを良好に圧着することができ、ディスプレイ装置の表示ムラを低減することができ、両面粘着テープを被着体から剥がす際には容易に上記発泡体基材を引裂くことができる。上記２５％圧縮強度のより好ましい下限は０．０２ＭＰａ、より好ましい上限は０．０７ＭＰａであり、更に好ましい下限は０．０２５ＭＰａ、更に好ましい上限は０．０６５ＭＰａであり、更により好ましい下限は０．０３ＭＰａ、更により好ましい上限は０．０６ＭＰａである。
なお、２５％圧縮強度は、ＪＩＳ　Ｋ　６２５４：２０１０に準拠し測定することで求めることができる。
上記発泡体基材の２５％圧縮強度は、ウレタン樹脂組成物におけるポリイソシアネート及びポリオールの種類及び含有量を変化させることで調整することができる。原料が同じ場合であっても、気泡体積分率、気泡の長径分布の平均及び標準偏差等を適切な範囲に設定することで調整することができる。 The 25% compressive strength of the foam base material is not particularly limited, but the preferable lower limit is 0.015 MPa and the preferable upper limit is 0.08 MPa. When the 25% compression strength is 0.015 MPa or more, the strength of the foam base material is sufficiently high, and the drop impact resistance of the double-sided adhesive tape is improved. When the 25% compression strength is 0.08 MPa or less, it is possible to prevent the flexibility of the foam base material from being excessively lowered, so that the double-sided adhesive tape can be satisfactorily crimped, and the display device can be used. Display unevenness can be reduced, and the foam base material can be easily torn when the double-sided adhesive tape is peeled off from the adherend. The more preferable lower limit of the 25% compression strength is 0.02 MPa, the more preferable upper limit is 0.07 MPa, the further preferable lower limit is 0.025 MPa, the further preferable upper limit is 0.065 MPa, and the further preferable lower limit is 0.03 MPa. An even more preferable upper limit is 0.06 MPa.
The 25% compression strength can be determined by measuring in accordance with JIS K 6254: 2010.
The 25% compressive strength of the foam base material can be adjusted by changing the type and content of the polyisocyanate and the polyol in the urethane resin composition. Even when the raw materials are the same, it can be adjusted by setting the volume fraction of bubbles, the average of the major axis distribution of bubbles, the standard deviation, and the like within appropriate ranges.
上記発泡体基材のガラス転移点は特に限定されないが、好ましい下限は－３０℃、好ましい上限は３０℃である。上記発泡体基材のガラス転移点が－３０℃以上であれば、上記発泡体基材が良好な低反発性を示し、応力を緩和することができる。上記発泡体基材のガラス転移点が３０℃以下であれば、上記発泡体基材が適度な柔軟性を有することができ、また、伸びやすい発泡体となって強度と柔軟性とが高くなる。上記発泡体基材のガラス転移点のより好ましい下限は－２５℃、より好ましい上限は２０℃である。
なお、ガラス転移点は、粘弾性測定装置（例えば、レオメトリックス社製「Ｒｈｅｏｍｅｔｒｉｃｓ　Ｄｙｎａｍｉｃ　Ａｎａｌｙｚｅ　ＲＤＡ－７００）を使用して、測定温度－３０～１００℃、昇温速度３℃／ｍｉｎ、周波数１Ｈｚの条件下で求めることができる。 The glass transition point of the foam base material is not particularly limited, but a preferable lower limit is −30 ° C. and a preferable upper limit is 30 ° C. When the glass transition point of the foam base material is −30 ° C. or higher, the foam base material exhibits good low resilience and can relieve stress. When the glass transition point of the foam base material is 30 ° C. or lower, the foam base material can have appropriate flexibility, and the foam becomes an easily stretchable foam, and the strength and flexibility are increased. .. The more preferable lower limit of the glass transition point of the foam base material is −25 ° C., and the more preferable upper limit is 20 ° C.
The glass transition point is measured using a viscoelasticity measuring device (for example, "Rheometrics Dynamic Analog RDA-700" manufactured by Leometrics) at a measurement temperature of -30 to 100 ° C., a heating rate of 3 ° C./min, and a frequency of 1 Hz. It can be determined under the conditions.
上記発泡体基材の厚みは特に限定されないが、好ましい下限は１００μｍ、好ましい上限は１０００μｍである。上記発泡体基材の厚みが１００μｍ以上であれば、上記発泡体基材が適度な柔軟性を有することができる。上記発泡体基材の厚みが１０００μｍ以下であれば、気泡の大きさのばらつきを抑えることができ、また、輸送時の落下等により衝撃が加わることで上記発泡体基材が伸びて破断することを抑えることができる。上記発泡体基材の厚みのより好ましい下限は１５０μｍ、より好ましい上限は９５０μｍであり、更に好ましい下限は３００μｍ、更に好ましい上限は７５０μｍであり、更により好ましい下限は４５０μｍ、更により好ましい上限は７００μｍである。
なお、発泡体基材の厚みは、ダイヤル厚み計（例えば、Ｍｉｔｕｔｏｙｏ社製、「ＡＢＳデジマチックインジケーター」）を使用して測定できる。 The thickness of the foam base material is not particularly limited, but the preferable lower limit is 100 μm and the preferable upper limit is 1000 μm. When the thickness of the foam base material is 100 μm or more, the foam base material can have appropriate flexibility. When the thickness of the foam base material is 1000 μm or less, it is possible to suppress variations in the size of bubbles, and the foam base material stretches and breaks when an impact is applied due to dropping during transportation or the like. Can be suppressed. A more preferable lower limit of the thickness of the foam base material is 150 μm, a more preferable upper limit is 950 μm, a further preferable lower limit is 300 μm, a further preferable upper limit is 750 μm, a further preferable lower limit is 450 μm, and a further preferable upper limit is 700 μm. is there.
The thickness of the foam base material can be measured using a dial thickness gauge (for example, "ABS Digimatic Indicator" manufactured by Mitutoyo Co., Ltd.).
本発明の両面粘着テープは、更に、上記発泡体基材の少なくとも片側に樹脂シートを有していてもよい。上記樹脂シートを用いることで、取り扱い時に上記発泡体基材が伸びて破断することを抑止することができ、かつ、両面粘着テープにリワーク性を付与することができる。
上記樹脂シートは、上記発泡体基材の片側に積層されていてもよく、両側に積層されていてもよい。
上記樹脂シートを構成する樹脂は特に限定されず、例えば、ポリエチレンテレフタレート等のポリエステル系樹脂、アクリル系樹脂、ポリエチレン系樹脂、ポリプロピレン系樹脂、ポリ塩化ビニル、エポキシ樹脂、シリコーン樹脂、フェノール樹脂、ポリイミド、ポリエステル、ポリカーボネート等が挙げられる。なかでも、柔軟性に優れていることから、アクリル系樹脂、ポリエチレン系樹脂、ポリプロピレン系樹脂、ポリエステル系樹脂が好ましい。ポリエステル系樹脂のなかでは、ポリエチレンテレフタレートが好ましい。 The double-sided adhesive tape of the present invention may further have a resin sheet on at least one side of the foam base material. By using the resin sheet, it is possible to prevent the foam base material from stretching and breaking during handling, and it is possible to impart reworkability to the double-sided adhesive tape.
The resin sheet may be laminated on one side of the foam base material, or may be laminated on both sides.
The resin constituting the resin sheet is not particularly limited, and for example, polyester resin such as polyethylene terephthalate, acrylic resin, polyethylene resin, polypropylene resin, polyvinyl chloride, epoxy resin, silicone resin, phenol resin, polyimide, etc. Examples include polyester and polypropylene. Of these, acrylic resins, polyethylene resins, polypropylene resins, and polyester resins are preferable because of their excellent flexibility. Among the polyester-based resins, polyethylene terephthalate is preferable.
また、上記樹脂シートを構成する樹脂は、熱可塑性樹脂であってもよい。上記熱可塑性樹脂は特に限定されず、例えば、スチレン系（共）重合体、オレフィン系（共）重合体、塩化ビニル系（共）重合体、ポリエーテルエステル系トリブロック系（共）重合体、ポリエステル系（共）重合体、ウレタン系（共）重合体、アミド系（共）重合体、アクリル系（共）重合体等が挙げられる。なかでも、弾性体としての強度、伸び、柔軟性、自己粘着性を発揮することができ、優れたリワーク性を発揮しながら、樹脂シートと発泡体基材との密着性をより向上させることができる観点から、上記熱可塑性樹脂がアクリル系（共）重合体、スチレン系（共）重合体又はオレフィン系（共）重合体であることが好ましい。更に、アクリル系（共）重合体又はスチレン系（共）重合体であることがより好ましく、スチレン系（共）重合体であることが更に好ましい。 Further, the resin constituting the resin sheet may be a thermoplastic resin. The thermoplastic resin is not particularly limited, and for example, a styrene-based (co) polymer, an olefin-based (co) polymer, a vinyl chloride-based (co) polymer, a polyether ester-based triblock-based (co) polymer, and the like. Examples thereof include polyester-based (co) polymers, urethane-based (co) polymers, amide-based (co) polymers, and acrylic (co) polymers. Above all, it is possible to exhibit strength, elongation, flexibility, and self-adhesiveness as an elastic body, and it is possible to further improve the adhesion between the resin sheet and the foam base material while exhibiting excellent reworkability. From the viewpoint of being able to do so, it is preferable that the thermoplastic resin is an acrylic (co) polymer, a styrene (co) polymer, or an olefin (co) polymer. Further, it is more preferably an acrylic (co) polymer or a styrene (co) polymer, and further preferably a styrene (co) polymer.
上記樹脂シートを構成する樹脂が熱可塑性樹脂である場合、上記樹脂シートは、引張弾性率が２００ＭＰａ以下であることが好ましい。引張弾性率が２００ＭＰａ以下である柔軟な樹脂を用いることにより、両面粘着テープ全体の柔軟性を確保して、両面粘着テープをロール状に巻き取ることが容易となり、取り扱い性が格段に向上する。
なお、引張弾性率は、ＪＩＳ　Ｋ　７１６１に準ずる方法により測定することができる。具体的には例えば、例えば高分子計器社製の打ち抜き刃「引張１号型ダンベル状」等を用いて、樹脂シートをダンベル状に打ち抜いて試験片を作製する。得られた試験片の引張弾性率を、例えば島津製作所社製「オートグラフＡＧＳ－Ｘ」等を用いて、引張速度１００ｍｍ／ｍｉｎで測定する。１～３％の歪み間の引張強度の傾きから引張弾性率を算出する。 When the resin constituting the resin sheet is a thermoplastic resin, the resin sheet preferably has a tensile elastic modulus of 200 MPa or less. By using a flexible resin having a tensile elastic modulus of 200 MPa or less, the flexibility of the entire double-sided adhesive tape is ensured, the double-sided adhesive tape can be easily wound into a roll, and the handleability is remarkably improved.
The tensile elastic modulus can be measured by a method according to JIS K 7161. Specifically, for example, a resin sheet is punched into a dumbbell shape using a punching blade "Tension No. 1 type dumbbell shape" manufactured by Polymer Instruments Co., Ltd. to prepare a test piece. The tensile elastic modulus of the obtained test piece is measured at a tensile speed of 100 mm / min using, for example, "Autograph AGS-X" manufactured by Shimadzu Corporation. The tensile elastic modulus is calculated from the slope of the tensile strength between the strains of 1 to 3%.
上記樹脂シートが上記発泡体基材の両側に積層されている場合、少なくとも一方の樹脂シートを構成する樹脂は、熱可塑性樹脂であることが好ましい。即ち、本発明の両面粘着テープは、熱可塑性樹脂から構成される樹脂シートを有することが好ましい。
本発明の両面粘着テープは、上記発泡体基材の第１の面に積層された第１の樹脂シートと、上記発泡体基材の第２の面に積層された第２の樹脂シートとを有し、上記第１の樹脂シート及び上記第２の樹脂シートからなる群より選択される少なくとも一方は、熱可塑性樹脂から構成される樹脂シートであることが好ましい。 When the resin sheet is laminated on both sides of the foam base material, the resin constituting at least one of the resin sheets is preferably a thermoplastic resin. That is, the double-sided adhesive tape of the present invention preferably has a resin sheet made of a thermoplastic resin.
The double-sided adhesive tape of the present invention comprises a first resin sheet laminated on the first surface of the foam base material and a second resin sheet laminated on the second surface of the foam base material. At least one selected from the group consisting of the first resin sheet and the second resin sheet is preferably a resin sheet composed of a thermoplastic resin.
上記樹脂シートの厚みは特に限定されないが、好ましい下限は１０μｍ、好ましい上限は１００μｍである。上記樹脂シートの厚みが１０μｍ以上であれば、上記樹脂シートを引っ張った際にも上記樹脂シートが破断しにくくなる。上記樹脂シートの厚みが１００μｍ以下であれば、被着体への追従性の低下を抑制することができる。上記樹脂シートの厚みのより好ましい下限は１５μｍ、より好ましい上限は８０μｍであり、更に好ましい下限は２０μｍ、更に好ましい上限は６０μｍ、更により好ましい下限は２５μｍ、更により好ましい上限は５０μｍである。 The thickness of the resin sheet is not particularly limited, but the preferable lower limit is 10 μm and the preferable upper limit is 100 μm. If the thickness of the resin sheet is 10 μm or more, the resin sheet is less likely to break even when the resin sheet is pulled. When the thickness of the resin sheet is 100 μm or less, it is possible to suppress a decrease in followability to the adherend. A more preferable lower limit of the thickness of the resin sheet is 15 μm, a more preferable upper limit is 80 μm, a further preferable lower limit is 20 μm, a further preferable upper limit is 60 μm, a further preferable lower limit is 25 μm, and a further preferable upper limit is 50 μm.
上記樹脂シートは、着色されていてもよい。上記樹脂シートを着色することにより、両面粘着テープに遮光性を付与することができる。
上記樹脂シートを着色する方法は特に限定されず、例えば、上記樹脂シートを構成する樹脂にカーボンブラック、酸化チタン等の粒子又は微細な気泡を練り込む方法、上記樹脂シートの表面にインクを塗布する方法等が挙げられる。 The resin sheet may be colored. By coloring the resin sheet, it is possible to impart light-shielding properties to the double-sided adhesive tape.
The method of coloring the resin sheet is not particularly limited, and for example, a method of kneading particles such as carbon black or titanium oxide or fine bubbles into the resin constituting the resin sheet, or applying ink to the surface of the resin sheet. The method and the like can be mentioned.
上記発泡体基材の両側に積層された粘着剤層は、同じ組成であってもよいし、それぞれ異なる組成であってもよい。
上記粘着剤層は特に限定されず、例えば、アクリル粘着剤、ゴム系粘着剤、ウレタン粘着剤、シリコーン系粘着剤等からなる粘着剤層が挙げられる。なかでも、粘着力の調節が容易であり、光、熱、水分等に対し比較的安定で、様々な被着体に適用可能であることから、アクリル共重合体及び粘着付与剤を含有するアクリル粘着剤からなる粘着剤層であることが好ましい。 The pressure-sensitive adhesive layers laminated on both sides of the foam base material may have the same composition or different compositions.
The pressure-sensitive adhesive layer is not particularly limited, and examples thereof include a pressure-sensitive adhesive layer made of an acrylic pressure-sensitive adhesive, a rubber-based pressure-sensitive adhesive, a urethane pressure-sensitive adhesive, a silicone-based pressure-sensitive adhesive, and the like. Among them, acrylic containing an acrylic copolymer and a tackifier because the adhesive strength can be easily adjusted, it is relatively stable against light, heat, moisture, etc., and it can be applied to various adherends. It is preferably a pressure-sensitive adhesive layer made of a pressure-sensitive adhesive.
上記アクリル共重合体は、モノマー混合物を共重合して得られるものである。上記モノマー混合物を共重合して上記アクリル共重合体を得るには、上記モノマー混合物を、重合開始剤の存在下にてラジカル反応させればよい。上記モノマー混合物をラジカル反応させる方法、即ち、重合方法としては、従来公知の方法が用いられ、例えば、溶液重合（沸点重合又は定温重合）、乳化重合、懸濁重合、塊状重合等が挙げられる。上記モノマー混合物をラジカル反応させる際の反応方式としては、例えば、リビングラジカル重合、フリーラジカル重合等が挙げられる。 The acrylic copolymer is obtained by copolymerizing a monomer mixture. In order to copolymerize the monomer mixture to obtain the acrylic copolymer, the monomer mixture may be subjected to a radical reaction in the presence of a polymerization initiator. As a method of radically reacting the monomer mixture, that is, a polymerization method, a conventionally known method is used, and examples thereof include solution polymerization (boiling point polymerization or constant temperature polymerization), emulsion polymerization, suspension polymerization, and bulk polymerization. Examples of the reaction method for radically reacting the monomer mixture include living radical polymerization and free radical polymerization.
上記アクリル共重合体の数平均分子量（Ｍｎ）に対する重量平均分子量（Ｍｗ）の比（分子量分布、Ｍｗ／Ｍｎ）は特に限定されないが、好ましい下限は１．０５、好ましい上限は５．０である。上記分子量分布（Ｍｗ／Ｍｎ）が上記範囲内であれば、低分子量成分等の含有量が少なくなるため、上記粘着剤層の凝集力が上がり、両面粘着テープの耐落下衝撃性が向上する。上記分子量分布（Ｍｗ／Ｍｎ）のより好ましい上限は３．０、更に好ましい上限は２．５、特に好ましい上限は２．３である。上記分子量分布（Ｍｗ／Ｍｎ）を上記範囲に調整するためには、重合開始剤、重合温度等の重合条件を調整すればよい。
なお、数平均分子量（Ｍｎ）及び重量平均分子量（Ｍｗ）とは、ＧＰＣ（Ｇｅｌ　Ｐｅｒｍｅａｔｉｏｎ　Ｃｈｒｏｍａｔｏｇｒａｐｈｙ：ゲルパーミエーションクロマトグラフィ）による標準ポリスチレン換算の分子量である。ＧＰＣでは、例えば、２６９０　Ｓｅｐａｒａｔｉｏｎｓ　Ｍｏｄｅｌ（Ｗａｔｅｒｓ社製）等を使用できる。また、ＧＰＣ装置（例えば、東ソー社製、製品名「ＨＬＣ－８２２０」、カラム：ＴＳＫｇｅｌＳｕｒｐｅｒ　ＨＺＭ－Ｎ（４本））等も使用でき、溶媒としてテトラヒドロフランを用いることができ、測定条件として、例えば、４０℃、流量０．５ｍＬ／ｍｉｎを採用することができる。 The ratio of the weight average molecular weight (Mw) to the number average molecular weight (Mn) of the acrylic copolymer (molecular weight distribution, Mw / Mn) is not particularly limited, but the preferable lower limit is 1.05 and the preferable upper limit is 5.0. .. When the molecular weight distribution (Mw / Mn) is within the above range, the content of the low molecular weight component and the like is reduced, so that the cohesive force of the pressure-sensitive adhesive layer is increased and the drop impact resistance of the double-sided pressure-sensitive adhesive tape is improved. The more preferable upper limit of the molecular weight distribution (Mw / Mn) is 3.0, the more preferable upper limit is 2.5, and the particularly preferable upper limit is 2.3. In order to adjust the molecular weight distribution (Mw / Mn) to the above range, the polymerization conditions such as the polymerization initiator and the polymerization temperature may be adjusted.
The number average molecular weight (Mn) and the weight average molecular weight (Mw) are standard polystyrene-equivalent molecular weights obtained by GPC (Gel Permeation Chromatography: Gel Permeation Chromatography). In GPC, for example, 2690 Separations Model (manufactured by Waters) or the like can be used. Further, a GPC apparatus (for example, manufactured by Tosoh Corporation, product name "HLC-8220", column: TSKgelSuper HZM-N (4 pieces)) or the like can be used, and tetrahydrofuran can be used as a solvent, and as a measurement condition, for example, 40 ° C. and a flow rate of 0.5 mL / min can be adopted.
上記アクリル共重合体の分子量分布（Ｍｗ／Ｍｎ）が２．５以下である場合、上記アクリル共重合体は、２－エチルヘキシルアクリレートに由来する構成単位を含有することが好ましい。
上記アクリル共重合体の分子量分布（Ｍｗ／Ｍｎ）が２．５以下である場合、上記２－エチルヘキシルアクリレートに由来する構成単位の含有量は特に限定されないが、好ましい下限は８０重量％、好ましい上限は９８重量％である。上記構成単位の含有量が８０重量％以上であれば、上記アクリル共重合体のガラス転移点が下がり、上記粘着剤層の被着体に対する濡れ性が高くなり、両面粘着テープの耐落下衝撃性が向上する。上記構成単位の含有量が９８重量％以下であれば、上記粘着剤層の凝集力が上がり、両面粘着テープの耐落下衝撃性が向上する。上記構成単位の含有量のより好ましい下限は９０重量％、より好ましい上限は９７重量％である。 When the molecular weight distribution (Mw / Mn) of the acrylic copolymer is 2.5 or less, the acrylic copolymer preferably contains a structural unit derived from 2-ethylhexyl acrylate.
When the molecular weight distribution (Mw / Mn) of the acrylic copolymer is 2.5 or less, the content of the structural unit derived from the 2-ethylhexyl acrylate is not particularly limited, but the preferable lower limit is 80% by weight and the preferable upper limit. Is 98% by weight. When the content of the structural unit is 80% by weight or more, the glass transition point of the acrylic copolymer is lowered, the wettability of the pressure-sensitive adhesive layer to the adherend is high, and the drop impact resistance of the double-sided adhesive tape is high. Is improved. When the content of the structural unit is 98% by weight or less, the cohesive force of the pressure-sensitive adhesive layer is increased, and the drop impact resistance of the double-sided pressure-sensitive adhesive tape is improved. A more preferable lower limit of the content of the structural unit is 90% by weight, and a more preferable upper limit is 97% by weight.
上記アクリル共重合体の分子量分布（Ｍｗ／Ｍｎ）が２．５以上である場合、上記アクリル共重合体は、炭素数４以下のアルキル基を有する（メタ）アクリル酸アルキルエステルに由来する構成単位を含有することが好ましい。
上記アクリル共重合体の分子量分布（Ｍｗ／Ｍｎ）が２．５以上である場合、上記炭素数４以下のアルキル基を有する（メタ）アクリル酸アルキルエステルとしては、特に限定されない。上記炭素数４以下のアルキル基を有する（メタ）アクリル酸アルキルエステルとしては、例えば、メチル（メタ）アクリレート、エチル（メタ）アクリレート、ｎ－プロピル（メタ）アクリレート、イソプロピル（メタ）アクリレート、ｎ－ブチル（メタ）アクリレート等が挙げられる。なかでも、エチル（メタ）アクリレート及びｎ－ブチル（メタ）アクリレートが好ましく、これらのアクリレートがより好ましい。これらの炭素数４以下のアルキル基を有する（メタ）アクリル酸アルキルエステルは単独で用いてもよいし、２種以上を併用してもよい。 When the molecular weight distribution (Mw / Mn) of the acrylic copolymer is 2.5 or more, the acrylic copolymer is a structural unit derived from a (meth) acrylic acid alkyl ester having an alkyl group having 4 or less carbon atoms. Is preferably contained.
When the molecular weight distribution (Mw / Mn) of the acrylic copolymer is 2.5 or more, the (meth) acrylic acid alkyl ester having an alkyl group having 4 or less carbon atoms is not particularly limited. Examples of the (meth) acrylic acid alkyl ester having an alkyl group having 4 or less carbon atoms include methyl (meth) acrylate, ethyl (meth) acrylate, n-propyl (meth) acrylate, isopropyl (meth) acrylate, and n-. Butyl (meth) acrylate and the like can be mentioned. Of these, ethyl (meth) acrylate and n-butyl (meth) acrylate are preferable, and these acrylates are more preferable. These (meth) acrylic acid alkyl esters having an alkyl group having 4 or less carbon atoms may be used alone or in combination of two or more.
上記アクリル共重合体の分子量分布（Ｍｗ／Ｍｎ）が２．５以上である場合、上記炭素数４以下のアルキル基を有する（メタ）アクリル酸アルキルエステルに由来する構成単位の含有量は特に限定されないが、好ましい下限は４０重量％、好ましい上限は８０重量％である。上記構成単位の含有量が４０重量％以上であれば、上記粘着剤層の凝集力が上がり、両面粘着テープの耐落下衝撃性が向上する。上記構成単位の含有量が８０重量％以下であれば、上記粘着剤層の被着体に対する濡れ性が低下しすぎることを抑制することができ、両面粘着テープの耐落下衝撃性が向上する。 When the molecular weight distribution (Mw / Mn) of the acrylic copolymer is 2.5 or more, the content of the structural unit derived from the (meth) acrylic acid alkyl ester having an alkyl group having 4 or less carbon atoms is particularly limited. However, the preferred lower limit is 40% by weight and the preferred upper limit is 80% by weight. When the content of the structural unit is 40% by weight or more, the cohesive force of the pressure-sensitive adhesive layer is increased, and the drop impact resistance of the double-sided pressure-sensitive adhesive tape is improved. When the content of the structural unit is 80% by weight or less, it is possible to suppress the wettability of the pressure-sensitive adhesive layer from being excessively lowered to the adherend, and the drop impact resistance of the double-sided pressure-sensitive adhesive tape is improved.
上記アクリル共重合体の分子量分布（Ｍｗ／Ｍｎ）が２．５以上である場合もまた、上記アクリル共重合体は、２－エチルヘキシルアクリレートに由来する構成単位を含有することが好ましい。
上記アクリル共重合体の分子量分布（Ｍｗ／Ｍｎ）が２．５以上である場合、上記２－エチルヘキシルアクリレートに由来する構成単位の含有量は特に限定されないが、好ましい下限は１０重量％、好ましい上限は４０重量％である。上記構成単位の含有量が１０重量％以上であれば、上記粘着剤層の凝集力が上がり、両面粘着テープの耐落下衝撃性が向上する。上記構成単位の含有量が４０重量％以下であれば、上記粘着剤層の凝集力が低下しすぎることを抑制することができ、両面粘着テープの耐落下衝撃性が向上する。 When the molecular weight distribution (Mw / Mn) of the acrylic copolymer is 2.5 or more, the acrylic copolymer preferably contains a structural unit derived from 2-ethylhexyl acrylate.
When the molecular weight distribution (Mw / Mn) of the acrylic copolymer is 2.5 or more, the content of the structural unit derived from the 2-ethylhexyl acrylate is not particularly limited, but the preferable lower limit is 10% by weight and the preferable upper limit. Is 40% by weight. When the content of the structural unit is 10% by weight or more, the cohesive force of the pressure-sensitive adhesive layer is increased, and the drop impact resistance of the double-sided pressure-sensitive adhesive tape is improved. When the content of the structural unit is 40% by weight or less, it is possible to suppress the cohesive force of the pressure-sensitive adhesive layer from being excessively lowered, and the drop impact resistance of the double-sided pressure-sensitive adhesive tape is improved.
上記アクリル共重合体は、必要に応じて上記２－エチルヘキシルアクリレートに由来する構成単位及び上記炭素数４以下のアルキル基を有する（メタ）アクリル酸アルキルエステルに由来する構成単位以外の共重合可能な他の重合性モノマーに由来する構成単位を含んでいてもよい。
上記共重合可能な他の重合性モノマーとして、例えば、炭素数１３～１８のアルキル基を有する（メタ）アクリル酸アルキルエステル、官能性モノマー等が挙げられる。
上記炭素数１３～１８のアルキル基を有する（メタ）アクリル酸アルキルエステルとして、例えば、メタクリル酸トリデシル、（メタ）アクリル酸ステアリル等が挙げられる。上記官能性モノマーとして、例えば、（メタ）アクリル酸ヒドロキシアルキル、グリセリンジメタクリレート、（メタ）アクリル酸グリシジル、２－メタクリロイルオキシエチルイソシアネート、（メタ）アクリル酸、イタコン酸、無水マレイン酸、クロトン酸、マレイン酸、フマル酸等が挙げられる。
これらの共重合可能な他の重合性モノマーは単独で用いてもよいし、２種以上を併用してもよい。なかでも、架橋剤と架橋構造を形成することで上記粘着剤層のゲル分率を調整しやすくなることから、水酸基やカルボキシル基のような極性官能基を有する官能性モノマーが好ましく、水酸基を有する官能性モノマーがより好ましい。即ち、上記アクリル共重合体は、水酸基を含有することが好ましい。 The acrylic copolymer can be copolymerized, if necessary, other than the structural unit derived from the 2-ethylhexyl acrylate and the structural unit derived from the (meth) acrylic acid alkyl ester having an alkyl group having 4 or less carbon atoms. It may contain structural units derived from other polymerizable monomers.
Examples of the other copolymerizable monomer include a (meth) acrylic acid alkyl ester having an alkyl group having 13 to 18 carbon atoms, a functional monomer and the like.
Examples of the (meth) acrylic acid alkyl ester having an alkyl group having 13 to 18 carbon atoms include tridecylic methacrylate and stearyl (meth) acrylic acid. Examples of the functional monomer include hydroxyalkyl (meth) acrylic acid, glycerin dimethacrylate, glycidyl (meth) acrylate, 2-methacryloyloxyethyl isocyanate, (meth) acrylic acid, itaconic acid, maleic anhydride, and crotonic acid. Maleic acid, fumaric acid and the like can be mentioned.
These other copolymerizable monomers may be used alone or in combination of two or more. Among them, a functional monomer having a polar functional group such as a hydroxyl group or a carboxyl group is preferable, and a functional monomer having a hydroxyl group is preferable because the gel fraction of the pressure-sensitive adhesive layer can be easily adjusted by forming a cross-linked structure with the cross-linking agent. Functional monomers are more preferred. That is, the acrylic copolymer preferably contains a hydroxyl group.
上記アクリル共重合体の重量平均分子量（Ｍｗ）は、好ましい下限が３０万、好ましい上限が２００万である。上記重量平均分子量が３０万以上であれば、上記粘着剤層が適度な硬さとなって凝集力が充分となり、粘着力が高くなる。上記重量平均分子量が２００万以下であれば、上記粘着剤層の粘着力が充分となる。上記重量平均分子量のより好ましい下限は５０万、より好ましい上限は１４０万である。上記重量平均分子量を上記範囲に調整するためには、重合開始剤、重合温度等の重合条件を調整すればよい。 The weight average molecular weight (Mw) of the acrylic copolymer has a preferable lower limit of 300,000 and a preferable upper limit of 2 million. When the weight average molecular weight is 300,000 or more, the pressure-sensitive adhesive layer has an appropriate hardness, sufficient cohesive force, and high adhesive force. When the weight average molecular weight is 2 million or less, the adhesive strength of the pressure-sensitive adhesive layer is sufficient. The more preferable lower limit of the weight average molecular weight is 500,000, and the more preferable upper limit is 1.4 million. In order to adjust the weight average molecular weight within the above range, the polymerization conditions such as the polymerization initiator and the polymerization temperature may be adjusted.
上記重合開始剤として、例えば、有機過酸化物、アゾ化合物等が挙げられる。
上記有機過酸化物として、例えば、１，１－ビス（ｔ－ヘキシルパーオキシ）－３，３，５－トリメチルシクロヘキサン、ｔ－ヘキシルパーオキシピバレート、ｔ－ブチルパーオキシピバレート、２，５－ジメチル－２，５－ビス（２－エチルヘキサノイルパーオキシ）ヘキサン、ｔ－ヘキシルパーオキシ－２－エチルヘキサノエート、ｔ－ブチルパーオキシ－２－エチルヘキサノエート、ｔ－ブチルパーオキシイソブチレート、ｔ－ブチルパーオキシ－３，５，５－トリメチルヘキサノエート、ｔ－ブチルパーオキシラウレート等が挙げられる。
上記アゾ化合物は、ラジカル重合に一般的に用いられるものであれば特に限定されない。上記アゾ化合物として、例えば、２，２’－アゾビス（イソブチロニトリル）、２，２’－アゾビス（２－メチルブチロニトリル）、２，２’－アゾビス（２，４－ジメチルバレロニトリル）、２，２’－アゾビス（４－メトキシ－２，４－ジメチルバレロニトリル）、１，１－アゾビス（シクロヘキサン－１－カルボニトリル）、１－［（１－シアノ－１－メチルエチル）アゾ］ホルムアミド、４，４’－アゾビス（４－シアノバレリアン酸）、ジメチル－２，２’－アゾビス（２－メチルプロピオネート）、ジメチル－１，１’－アゾビス（１－シクロヘキサンカルボキシレート）、２，２’－アゾビス｛２－メチル－Ｎ－［１，１’－ビス（ヒドロキシメチル）－２－ヒドロキシエチル］プロピオンアミド｝、２，２’－アゾビス［２－メチル－Ｎ－（２－ヒドロキシエチル）プロピオンアミド］、２，２’－アゾビス［Ｎ－（２－プロペニル）－２－メチルプロピオンアミド］、２，２’－アゾビス（Ｎ－ブチル－２－メチルプロピオンアミド）、２，２’－アゾビス（Ｎ－シクロヘキシル－２－メチルプロピオンアミド）、２，２’－アゾビス［２－（２－イミダゾリン－２－イル）プロパン］二塩酸塩、２，２’－アゾビス｛２－［１－（２－ヒドロキシエチル）－２－イミダゾリン－２－イル］プロパン｝二塩酸塩、２，２’－アゾビス［２－（２－イミダゾリン－２－イル）プロパン］、２，２’－アゾビス（２－アミジノプロパン）二塩酸塩、２，２’－アゾビス［Ｎ－（２－カルボキシエチル）－２－メチルプロピオンアミジン］四水和物、２，２’－アゾビス（１－イミノ－１－ピロリジノ－２－メチルプロパン）二塩酸塩、２，２’－アゾビス（２，４，４－トリメチルペンタン）等が挙げられる。
また、上記重合開始剤として、リビングラジカル重合を開始させる重合開始剤は特に限定されないが、有機テルル重合開始剤が好ましい。
これらの重合開始剤は単独で用いてもよいし、２種以上を併用してもよい。 Examples of the polymerization initiator include organic peroxides and azo compounds.
Examples of the organic peroxide include 1,1-bis (t-hexyl peroxy) -3,3,5-trimethylcyclohexane, t-hexyl peroxypivalate, t-butylperoxypivalate, 2,5. -Dimethyl-2,5-bis (2-ethylhexanoylperoxy) hexane, t-hexylperoxy-2-ethylhexanoate, t-butylperoxy-2-ethylhexanoate, t-butylperoxy Examples thereof include isobutyrate, t-butylperoxy-3,5,5-trimethylhexanoate and t-butylperoxylaurate.
The azo compound is not particularly limited as long as it is generally used for radical polymerization. Examples of the azo compound include 2,2'-azobis (isobutyronitrile), 2,2'-azobis (2-methylbutyronitrile), and 2,2'-azobis (2,4-dimethylvaleronitrile). , 2,2'-azobis (4-methoxy-2,4-dimethylvaleronitrile), 1,1-azobis (cyclohexane-1-carbonitrile), 1-[(1-cyano-1-methylethyl) azo] Formamide, 4,4'-azobis (4-cyanovalerian acid), dimethyl-2,2'-azobis (2-methylpropionate), dimethyl-1,1'-azobis (1-cyclohexanecarboxylate), 2 , 2'-azobis {2-methyl-N- [1,1'-bis (hydroxymethyl) -2-hydroxyethyl] propionamide}, 2,2'-azobis [2-methyl-N- (2-hydroxy) Ethyl) propionamide], 2,2'-azobis [N- (2-propenyl) -2-methylpropionamide], 2,2'-azobis (N-butyl-2-methylpropionamide), 2,2' -Azobis (N-cyclohexyl-2-methylpropionamide), 2,2'-azobis [2- (2-imidazolin-2-yl) propane] dihydrochloride, 2,2'-azobis {2- [1-] (2-Hydroxyethyl) -2-imidazolin-2-yl] propane} dihydrochloride, 2,2'-azobis [2- (2-imidazolin-2-yl) propane], 2,2'-azobis (2) -Amidinopropane) dihydrochloride, 2,2'-azobis [N- (2-carboxyethyl) -2-methylpropion amidine] tetrahydrate, 2,2'-azobis (1-imino-1-pyrrolidino-) 2-Methylpropane) dihydrochloride, 2,2'-azobis (2,4,4-trimethylpentane) and the like can be mentioned.
Further, as the above-mentioned polymerization initiator, the polymerization initiator that initiates living radical polymerization is not particularly limited, but an organic tellurium polymerization initiator is preferable.
These polymerization initiators may be used alone or in combination of two or more.
上記モノマー混合物をラジカル反応させる際には、分散安定剤を用いてもよい。上記分散安定剤として、例えば、ポリビニルピロリドン、ポリビニルアルコール、メチルセルロース、エチルセルロース、ポリ（メタ）アクリル酸、ポリ（メタ）アクリル酸エステル、ポリエチレングリコール等が挙げられる。 A dispersion stabilizer may be used when the above-mentioned monomer mixture is radically reacted. Examples of the dispersion stabilizer include polyvinylpyrrolidone, polyvinyl alcohol, methyl cellulose, ethyl cellulose, poly (meth) acrylic acid, poly (meth) acrylic acid ester, polyethylene glycol and the like.
上記モノマー混合物をラジカル反応させる際に重合溶媒を用いる場合、該重合溶媒は特に限定されない。上記重合溶媒として、例えば、ヘキサン、シクロヘキサン、オクタン、トルエン、キシレン等の非極性溶媒を用いることができる。また、上記重合溶媒として、例えば、水、メタノール、エタノール、プロパノール、ブタノール、アセトン、メチルエチルケトン、メチルイソブチルケトン、テトラヒドロフラン、ジオキサン、Ｎ，Ｎ－ジメチルホルムアミド等の高極性溶媒を用いることができる。これらの重合溶媒は単独で用いてもよいし、２種以上を併用してもよい。重合温度は、重合速度の観点から０～１１０℃が好ましい。 When a polymerization solvent is used in the radical reaction of the monomer mixture, the polymerization solvent is not particularly limited. As the polymerization solvent, for example, a non-polar solvent such as hexane, cyclohexane, octane, toluene, or xylene can be used. Further, as the above-mentioned polymerization solvent, for example, a highly polar solvent such as water, methanol, ethanol, propanol, butanol, acetone, methyl ethyl ketone, methyl isobutyl ketone, tetrahydrofuran, dioxane, N, N-dimethylformamide can be used. These polymerization solvents may be used alone or in combination of two or more. The polymerization temperature is preferably 0 to 110 ° C. from the viewpoint of the polymerization rate.
上記粘着付与剤として、例えば、ロジン系樹脂、ロジンエステル系樹脂、水添ロジン系樹脂、テルペン系樹脂、テルペンフェノール系樹脂、クマロンインデン系樹脂、脂環族飽和炭化水素系樹脂、Ｃ５系石油樹脂、Ｃ９系石油樹脂、Ｃ５－Ｃ９共重合系石油樹脂等が挙げられる。これらの粘着付与剤は単独で用いてもよいし、２種以上を併用してもよい。なかでも、ロジン系樹脂又はテルペン系樹脂が好ましく、水酸基を含有するロジン系樹脂又は水酸基を含有するテルペン系樹脂がより好ましい。 Examples of the tackifier include rosin-based resin, rosin ester-based resin, hydrogenated rosin-based resin, terpene-based resin, terpene phenol-based resin, kumaron inden-based resin, alicyclic saturated hydrocarbon-based resin, and C5-based petroleum. Examples thereof include resins, C9-based petroleum resins, and C5-C9 copolymerized petroleum resins. These tackifiers may be used alone or in combination of two or more. Of these, a rosin-based resin or a terpene-based resin is preferable, and a rosin-based resin containing a hydroxyl group or a terpene-based resin containing a hydroxyl group is more preferable.
上記粘着付与剤は、軟化温度の好ましい下限が７０℃、好ましい上限が１７０℃である。上記軟化温度が７０℃以上であれば、上記粘着剤層が柔らかくなりすぎて両面粘着テープの耐落下衝撃性が低下することを抑制することができる。上記軟化温度が１７０℃以下であれば、上記粘着剤層の被着体に対する濡れ性が高くなり、両面粘着テープの耐落下衝撃性が向上する。上記軟化温度のより好ましい下限は１２０℃である。
なお、軟化温度とは、ＪＩＳ　Ｋ２２０７環球法により測定した軟化温度である。 The pressure-sensitive adhesive has a preferable lower limit of the softening temperature of 70 ° C. and a preferred upper limit of 170 ° C. When the softening temperature is 70 ° C. or higher, it is possible to prevent the pressure-sensitive adhesive layer from becoming too soft and reducing the drop impact resistance of the double-sided adhesive tape. When the softening temperature is 170 ° C. or lower, the wettability of the pressure-sensitive adhesive layer to the adherend is high, and the drop impact resistance of the double-sided pressure-sensitive adhesive tape is improved. A more preferable lower limit of the softening temperature is 120 ° C.
The softening temperature is a softening temperature measured by the JIS K2207 ring-and-ball method.
上記粘着付与剤は、水酸基価の好ましい下限が２５、好ましい上限が１６０である。上記水酸基価が上記範囲内であることで、上記粘着剤層の被着体に対する濡れ性が高くなり、両面粘着テープの耐落下衝撃性が向上する。上記水酸基価のより好ましい下限は３０、より好ましい上限は１５０である。
なお、水酸基価は、ＪＩＳ　Ｋ１５５７（無水フタル酸法）により測定できる The tackifier has a preferred lower limit of 25 and a preferred upper limit of the hydroxyl value of 160. When the hydroxyl value is within the above range, the wettability of the pressure-sensitive adhesive layer to the adherend is increased, and the drop impact resistance of the double-sided adhesive tape is improved. The more preferable lower limit of the hydroxyl value is 30, and the more preferable upper limit is 150.
The hydroxyl value can be measured by JIS K1557 (phthalic anhydride method).
上記粘着付与剤の含有量は特に限定されないが、上記アクリル共重合体１００重量部に対する好ましい下限は１０重量部、好ましい上限は６０重量部である。上記粘着付与剤の含有量が１０重量部以上であれば、上記粘着剤層の粘着力が高くなる。上記粘着付与剤の含有量が６０重量部以下であれば、上記粘着剤層が硬くなりすぎて粘着力が低下することを抑制することができる。 The content of the tackifier is not particularly limited, but the preferable lower limit with respect to 100 parts by weight of the acrylic copolymer is 10 parts by weight, and the preferable upper limit is 60 parts by weight. When the content of the pressure-sensitive adhesive is 10 parts by weight or more, the adhesive strength of the pressure-sensitive adhesive layer is high. When the content of the pressure-sensitive adhesive is 60 parts by weight or less, it is possible to prevent the pressure-sensitive adhesive layer from becoming too hard and reducing the adhesive strength.
上記粘着剤層は、架橋剤が添加されることにより上記粘着剤層を構成する樹脂（例えば、上記アクリル共重合体、上記粘着付与剤等）の主鎖間に架橋構造が形成されていることが好ましい。上記架橋剤の種類及び量を調整することによって、上記粘着剤層のゲル分率を調整しやすくなる。
上記架橋剤は特に限定されず、例えば、イソシアネート系架橋剤、アジリジン系架橋剤、エポキシ系架橋剤、金属キレート型架橋剤等が挙げられる。なかでも、イソシアネート系架橋剤が好ましい。
上記架橋剤の添加量は、上記アクリル共重合体１００重量部に対する好ましい下限が０．０１重量部、好ましい上限が１０重量部であり、より好ましい下限が０．１重量部、より好ましい上限が３重量部である。 The pressure-sensitive adhesive layer has a cross-linked structure formed between the main chains of the resin (for example, the acrylic copolymer, the pressure-sensitive adhesive, etc.) constituting the pressure-sensitive adhesive layer by adding a cross-linking agent. Is preferable. By adjusting the type and amount of the cross-linking agent, it becomes easy to adjust the gel fraction of the pressure-sensitive adhesive layer.
The above-mentioned cross-linking agent is not particularly limited, and examples thereof include isocyanate-based cross-linking agents, aziridine-based cross-linking agents, epoxy-based cross-linking agents, and metal chelate-type cross-linking agents. Of these, isocyanate-based cross-linking agents are preferable.
Regarding the amount of the cross-linking agent added, the preferable lower limit is 0.01 parts by weight and the preferable upper limit is 10 parts by weight with respect to 100 parts by weight of the acrylic copolymer, the more preferable lower limit is 0.1 parts by weight, and the more preferable upper limit is 3. It is a part by weight.
上記粘着剤層は、粘着力を向上させる目的で、シランカップリング剤を含有してもよい。上記シランカップリング剤は特に限定されず、例えば、エポキシシラン類、アクリルシラン類、メタクリルシラン類、アミノシラン類、イソシアネートシラン類等が挙げられる。 The pressure-sensitive adhesive layer may contain a silane coupling agent for the purpose of improving the adhesive strength. The silane coupling agent is not particularly limited, and examples thereof include epoxysilanes, acrylicsilanes, methacrylsilanes, aminosilanes, and isocyanatesilanes.
上記粘着剤層は、遮光性を付与する目的で、着色材を含有してもよい。上記着色材は特に限定されず、例えば、カーボンブラック、アニリンブラック、酸化チタン等が挙げられる。なかでも、比較的安価で化学的に安定であることから、カーボンブラックが好ましい。 The pressure-sensitive adhesive layer may contain a coloring material for the purpose of imparting light-shielding properties. The coloring material is not particularly limited, and examples thereof include carbon black, aniline black, and titanium oxide. Of these, carbon black is preferable because it is relatively inexpensive and chemically stable.
上記粘着剤層のゲル分率は特に限定されないが、好ましい下限が１重量％、好ましい上限が９０重量％である。上記ゲル分率が１重量％以上であれば、上記粘着剤層の凝集力が上がり、両面粘着テープの耐落下衝撃性が向上する。上記ゲル分率が９０重量％以下であれば、上記粘着剤層の被着体に対する濡れ性が低下しすぎることを抑制することができ、両面粘着テープの耐落下衝撃性が向上する。上記ゲル分率のより好ましい下限は２０重量％、より好ましい上限は７０重量％であり、更に好ましい下限は３０重量％、更に好ましい上限は５０重量％である。
なお、粘着剤層のゲル分率は、以下の方法により測定できる。
両面粘着テープを５０ｍｍ×１００ｍｍの平面長方形状に裁断して試験片を作製する。試験片を酢酸エチル中に２３℃にて２４時間浸漬した後、酢酸エチルから取り出して、１１０℃の条件下で１時間乾燥させる。乾燥後の試験片の重量を測定し、下記式（５）を用いてゲル分率を算出する。なお、試験片には、粘着剤層を保護するための離型フィルムは積層されていないものとする。
ゲル分率（重量％）＝１００×（Ｗ２－Ｗ０）／（Ｗ１－Ｗ０）　　　（５）
（Ｗ０：基材の重量、Ｗ１：浸漬前の試験片の重量、Ｗ２：浸漬、乾燥後の試験片の重量） The gel fraction of the pressure-sensitive adhesive layer is not particularly limited, but the preferable lower limit is 1% by weight and the preferable upper limit is 90% by weight. When the gel fraction is 1% by weight or more, the cohesive force of the pressure-sensitive adhesive layer is increased, and the drop impact resistance of the double-sided pressure-sensitive adhesive tape is improved. When the gel fraction is 90% by weight or less, it is possible to suppress the wettability of the pressure-sensitive adhesive layer from being excessively lowered to the adherend, and the drop impact resistance of the double-sided pressure-sensitive adhesive tape is improved. The more preferable lower limit of the gel fraction is 20% by weight, the more preferable upper limit is 70% by weight, the further preferable lower limit is 30% by weight, and the further preferable upper limit is 50% by weight.
The gel fraction of the pressure-sensitive adhesive layer can be measured by the following method.
A test piece is prepared by cutting the double-sided adhesive tape into a flat rectangular shape of 50 mm × 100 mm. The test piece is immersed in ethyl acetate at 23 ° C. for 24 hours, then removed from ethyl acetate and dried under the condition of 110 ° C. for 1 hour. The weight of the test piece after drying is measured, and the gel fraction is calculated using the following formula (5). It is assumed that the test piece is not laminated with a release film for protecting the pressure-sensitive adhesive layer.
Gel fraction (% by weight) = 100 x (W 2- W 0 ) / (W 1- W 0 ) (5)
(W 0 : Weight of base material, W 1 : Weight of test piece before immersion, W 2 : Weight of test piece after immersion and drying)
上記粘着剤層の厚みは特に限定されないが、片側の粘着剤層の厚みの好ましい下限が２０μｍ、好ましい上限が１００μｍである。上記粘着剤層の厚みが２０μｍ以上であれば、上記粘着剤層の粘着力が充分となる。上記粘着剤層の厚みが１００μｍ以下であれば、上記発泡体基材の応力緩和性が両面粘着テープ全体としての応力緩和性にも充分に寄与することができる。上記粘着剤層の厚みのより好ましい下限は２５μｍ、より好ましい上限は８０μｍであり、更に好ましい下限は３０μｍ、更に好ましい上限は７０μｍであり、更により好ましい下限は３５μｍ、更により好ましい上限は６５μｍである。
なお、粘着剤層の厚みは、ダイヤル厚み計（例えば、Ｍｉｔｕｔｏｙｏ社製、「ＡＢＳデジマチックインジケーター」）を使用して測定できる。 The thickness of the pressure-sensitive adhesive layer is not particularly limited, but the preferable lower limit of the thickness of the pressure-sensitive adhesive layer on one side is 20 μm, and the preferable upper limit is 100 μm. When the thickness of the pressure-sensitive adhesive layer is 20 μm or more, the adhesive strength of the pressure-sensitive adhesive layer is sufficient. When the thickness of the pressure-sensitive adhesive layer is 100 μm or less, the stress relaxation property of the foam base material can sufficiently contribute to the stress relaxation property of the double-sided adhesive tape as a whole. A more preferable lower limit of the thickness of the pressure-sensitive adhesive layer is 25 μm, a more preferable upper limit is 80 μm, a further preferable lower limit is 30 μm, a further preferable upper limit is 70 μm, a further preferable lower limit is 35 μm, and a further preferable upper limit is 65 μm. ..
The thickness of the pressure-sensitive adhesive layer can be measured using a dial thickness gauge (for example, "ABS Digimatic Indicator" manufactured by Mitutoyo Co., Ltd.).
本発明の両面粘着テープの厚みは特に限定されないが、好ましい下限は１００μｍ、好ましい上限は１２００μｍである。上記厚みが１００μｍ以上であれば、両面粘着テープの粘着力が充分となり、また、応力緩和性も充分となる。上記厚みが１２００μｍ以下であれば、両面粘着テープによる充分な接着及び固定を実現することができる。上記厚みのより好ましい下限は２５０μｍ、より好ましい上限は９００μｍであり、更に好ましい下限は３５０μｍ、更に好ましい上限は７００μｍであり、更により好ましい下限は４００μｍ、更により好ましい上限は６５０μｍである。 The thickness of the double-sided adhesive tape of the present invention is not particularly limited, but a preferable lower limit is 100 μm and a preferable upper limit is 1200 μm. When the thickness is 100 μm or more, the adhesive strength of the double-sided adhesive tape is sufficient, and the stress relaxation property is also sufficient. When the thickness is 1200 μm or less, sufficient adhesion and fixing with the double-sided adhesive tape can be realized. A more preferable lower limit of the thickness is 250 μm, a more preferable upper limit is 900 μm, a further preferable lower limit is 350 μm, a further preferable upper limit is 700 μm, a further preferable lower limit is 400 μm, and a further preferable upper limit is 650 μm.
本発明の両面粘着テープの構成は特に限定されず、上記発泡体基材の表面上に上記粘着剤層が積層されていてもよく、上記発泡体基材と上記粘着剤層との間に上記樹脂シートが積層されていてもよい。 The configuration of the double-sided adhesive tape of the present invention is not particularly limited, and the pressure-sensitive adhesive layer may be laminated on the surface of the foam base material, and the pressure-sensitive adhesive layer may be laminated between the foam base material and the pressure-sensitive adhesive layer. Resin sheets may be laminated.
本発明の両面粘着テープの製造方法として、例えば、以下のような方法が挙げられる。
まず、アクリル共重合体、必要に応じて粘着付与剤、架橋剤等に溶剤を加えて粘着剤Ａの溶液を作製して、この粘着剤Ａの溶液を発泡体基材の表面に塗布し、溶液中の溶剤を完全に乾燥除去して粘着剤層Ａを形成する。次に、形成された粘着剤層Ａの上に離型フィルムをその離型処理面が粘着剤層Ａに対向した状態に重ね合わせる。
次いで、上記離型フィルムとは別の離型フィルムを用意し、この離型フィルムの離型処理面に粘着剤Ｂの溶液を塗布し、溶液中の溶剤を完全に乾燥除去することにより、離型フィルムの表面に粘着剤層Ｂが形成された積層フィルムを作製する。得られた積層フィルムを粘着剤層Ａが形成された発泡体基材の裏面に、粘着剤層Ｂが発泡体基材の裏面に対向した状態に重ね合わせて積層体を作製する。そして、上記積層体をゴムローラ等によって加圧する。これにより、発泡体基材の両側に粘着剤層を有し、かつ、粘着剤層の表面が離型フィルムで覆われた両面粘着テープを得ることができる。 Examples of the method for producing the double-sided adhesive tape of the present invention include the following methods.
First, a solvent is added to an acrylic copolymer, a pressure-sensitive adhesive, a cross-linking agent, etc. to prepare a solution of the pressure-sensitive adhesive A, and the solution of the pressure-sensitive adhesive A is applied to the surface of the foam base material. The solvent in the solution is completely dried and removed to form the pressure-sensitive adhesive layer A. Next, the release film is superposed on the formed pressure-sensitive adhesive layer A so that the release-treated surface faces the pressure-sensitive adhesive layer A.
Next, a release film different from the release film is prepared, a solution of the adhesive B is applied to the release-treated surface of the release film, and the solvent in the solution is completely dried and removed to release the film. A laminated film in which the pressure-sensitive adhesive layer B is formed on the surface of the mold film is produced. The obtained laminated film is laminated on the back surface of the foam base material on which the pressure-sensitive adhesive layer A is formed so that the pressure-sensitive adhesive layer B faces the back surface of the foam base material to prepare a laminate. Then, the laminate is pressed by a rubber roller or the like. This makes it possible to obtain a double-sided adhesive tape having adhesive layers on both sides of the foam base material and having the surface of the adhesive layer covered with a release film.
また、同様の要領で積層フィルムを２組作製し、これらの積層フィルムを発泡体基材の両側のそれぞれに、積層フィルムの粘着剤層を発泡体基材に対向させた状態に重ね合わせて積層体を作製し、この積層体をゴムローラ等によって加圧してもよい。これにより、発泡体基材の両側に粘着剤層を有し、かつ、粘着剤層の表面が離型フィルムで覆われた両面粘着テープを得ることができる。 Further, two sets of laminated films are produced in the same manner, and these laminated films are laminated on both sides of the foam base material by laminating the pressure-sensitive adhesive layer of the laminated film on each side of the foam base material so as to face the foam base material. A body may be produced and the laminated body may be pressurized with a rubber roller or the like. This makes it possible to obtain a double-sided adhesive tape having adhesive layers on both sides of the foam base material and having the surface of the adhesive layer covered with a release film.
本発明の両面粘着テープの用途は特に限定されず、例えば、電子機器における部品固定に用いられる。上記電子機器は特に限定されず、例えば、テレビ、モニター、携帯電子機器、車載用電子機器等が挙げられる。
なかでも、本発明の両面粘着テープは、テレビ、モニター等のディスプレイ装置、特に比較的大型のディスプレイ装置における部品固定に好適に用いられ、具体的には、例えば、上記ディスプレイ装置において表面のカバーパネルを筐体に固定するために用いられる。本発明の両面粘着テープは、耐落下衝撃性に優れ、ディスプレイ装置の表示ムラを低減することができることから、比較的大型のディスプレイ装置において細幅の両面粘着テープにより部品を固定する場合であっても好適に用いられる。本発明の両面粘着テープは細幅であってよく、その幅は特に限定されないが、好ましい下限は１０００μｍ、好ましい上限は１００００μｍであり、より好ましい下限は１５００μｍ、より好ましい上限は５０００μｍである。これらの用途における本発明の両面粘着テープの形状は特に限定されないが、長方形、額縁状、円形、楕円形、ドーナツ型等が挙げられる。
また、本発明の両面粘着テープは、車輌用内装、家電（例えば、ＴＶ、エアコン、冷蔵庫等）の内外装等に用いられてもよい。 The use of the double-sided adhesive tape of the present invention is not particularly limited, and is used, for example, for fixing parts in an electronic device. The electronic device is not particularly limited, and examples thereof include a television, a monitor, a portable electronic device, an in-vehicle electronic device, and the like.
Among them, the double-sided adhesive tape of the present invention is suitably used for fixing parts in display devices such as televisions and monitors, particularly in relatively large display devices. Specifically, for example, the surface cover panel in the above display device. Is used to fix the housing to the housing. Since the double-sided adhesive tape of the present invention has excellent drop impact resistance and can reduce display unevenness of the display device, it is a case where parts are fixed by a narrow double-sided adhesive tape in a relatively large display device. Is also preferably used. The double-sided adhesive tape of the present invention may have a narrow width, and the width is not particularly limited, but a preferable lower limit is 1000 μm, a preferable upper limit is 10000 μm, a more preferable lower limit is 1500 μm, and a more preferable upper limit is 5000 μm. The shape of the double-sided adhesive tape of the present invention in these applications is not particularly limited, and examples thereof include a rectangle, a frame, a circle, an ellipse, and a donut.
Further, the double-sided adhesive tape of the present invention may be used for the interior and exterior of vehicles, home appliances (for example, TVs, air conditioners, refrigerators, etc.).
本発明によれば、耐落下衝撃性に優れ、ディスプレイ装置の表示ムラを低減することができ、被着体から剥がす際には発泡体基材を容易に引裂くことができる両面粘着テープを提供することができる。 According to the present invention, there is provided a double-sided adhesive tape which is excellent in drop impact resistance, can reduce display unevenness of a display device, and can easily tear a foam base material when peeled from an adherend. can do.
せん断破断強度の測定方法を示す模式図である。It is a schematic diagram which shows the measuring method of the shear breaking strength. 両面粘着テープの層間引裂き試験を示す模式図である。It is a schematic diagram which shows the interlayer tear test of a double-sided adhesive tape. 両面粘着テープのタンブル試験用サンプルを示す模式図である。It is a schematic diagram which shows the sample for tumble test of a double-sided adhesive tape. 両面粘着テープの面うねり試験を示す模式図を示す。The schematic diagram which shows the surface waviness test of the double-sided adhesive tape is shown.
以下に実施例を挙げて本発明の態様を更に詳しく説明するが、本発明はこれら実施例にのみ限定されるものではない。 Hereinafter, embodiments of the present invention will be described in more detail with reference to examples, but the present invention is not limited to these examples.
（ポリウレタン発泡体１－１（ＰＵ１－１）の製造）
ポリオールとして、ポリプロピレングリコール（ＰＰＧ）（重量平均分子量１０００）９０重量部、１，５－ペンタンジオール１０重量部を用いた。
ポリオールの合計１００重量部にアミン触媒（ダブコＬＶ３３、三共エアープロダクト社製）を０．７重量部、整泡剤（ＳＺ５７４０Ｍ、東レ・ダウコーニング社製）を１重量部添加し、攪拌した。そこへポリイソシアネート（２核体モノメリックＭＤＩ、東ソー社製）をイソシアネートインデックス８５になるよう調整し投入した。その後、０．２ｇ／ｃｍ３になるように窒素ガスと混合攪拌し、微細な気泡が混入した溶液を得た。その溶液を厚み５０μｍのＰＥＴセパレーター（ニッパ製、Ｖ－２）上にアプリケーターを使用して所定の厚みに塗布し、発泡体原料を反応させ、ポリウレタン発泡体を得た。
ポリウレタン発泡体のせん断破断強度、２５％圧縮強度、及び、厚みを測定した。
ポリウレタン発泡体を切断して得た測定サンプルの中心部を、Ｘ線ＣＴ装置（ヤマト科学社製、「ＴＤＭ１０００Ｈ－ＩＩ（２Ｋ）」、解像度１．５μｍ／１ピクセル程度）により撮像し、長さ１．５ｍｍ、幅１．２ｍｍ、高さ０．３ｍｍの直方体状３Ｄ画像を得た。得られた画像について、画像解析ソフトウェア（ＦＥＩ社製、「Ａｖｉｚｏ９．２．０」）によりノイズ除去及び二値化を行い、気泡体積分率、気泡の長径分布の平均及び標準偏差、気泡の連泡率、気泡のアスペクト比及び気泡の扁平率を求めた。 (Manufacture of Polyurethane Foam 1-1 (PU1-1))
As the polyol, 90 parts by weight of polypropylene glycol (PPG) (weight average molecular weight 1000) and 10 parts by weight of 1,5-pentanediol were used.
0.7 parts by weight of an amine catalyst (Dabco LV33, manufactured by Sankyo Air Products Co., Ltd.) and 1 part by weight of a defoaming agent (SZ5740M, manufactured by Toray Dow Corning) were added to a total of 100 parts by weight of the polyol, and the mixture was stirred. Polyisocyanate (dinuclear monomeric MDI, manufactured by Tosoh Corporation) was adjusted and added thereto so as to have an isocyanate index of 85. Then, it was mixed and stirred with nitrogen gas so as to be 0.2 g / cm 3, and a solution containing fine bubbles was obtained. The solution was applied to a predetermined thickness on a PET separator (manufactured by nippers, V-2) having a thickness of 50 μm using an applicator, and the foam raw material was reacted to obtain a polyurethane foam.
The shear breaking strength, 25% compressive strength, and thickness of the polyurethane foam were measured.
The central part of the measurement sample obtained by cutting the polyurethane foam was imaged with an X-ray CT device (manufactured by Yamato Scientific Co., Ltd., "TDM1000H-II (2K)", resolution of about 1.5 μm / pixel), and the length was taken. A rectangular parallelepiped 3D image of 1.5 mm, width 1.2 mm, and height 0.3 mm was obtained. The obtained image is noise-removed and binarized by image analysis software (FEI, "Avizo 9.2.0"), and the volume fraction of bubbles, the average and standard deviation of the major axis distribution of bubbles, and the sequence of bubbles are performed. The bubble ratio, the aspect ratio of the bubbles and the flatness of the bubbles were determined.
（ポリウレタン発泡体１－２（ＰＵ１－２）の製造）
以下の点以外はポリウレタン発泡体１－１（ＰＵ１－１）の製造と同様にして、ポリウレタン発泡体を得た。
［１］ポリオールとして、ポリプロピレングリコール（ＰＰＧ）（重量平均分子量１０００）９０重量部、１，５－ペンタンジオール５重量部、１，６－ヘキサメチレンジオール５重量部を用いた。
［２］ポリイソシアネート（２核体モノメリックＭＤＩ、東ソー社製）をイソシアネートインデックス８５になるよう調整し投入した。 (Manufacturing of polyurethane foam 1-2 (PU1-2))
A polyurethane foam was obtained in the same manner as in the production of polyurethane foam 1-1 (PU1-1) except for the following points.
[1] As the polyol, 90 parts by weight of polypropylene glycol (PPG) (weight average molecular weight 1000), 5 parts by weight of 1,5-pentanediol, and 5 parts by weight of 1,6-hexamethylenediol were used.
[2] Polyisocyanate (dinuclear monomeric MDI, manufactured by Tosoh Corporation) was adjusted to have an isocyanate index of 85 and charged.
（ポリウレタン発泡体１－３（ＰＵ１－３）の製造）
以下の点以外はポリウレタン発泡体１－１（ＰＵ１－１）の製造と同様にして、ポリウレタン発泡体を得た。
［１］ポリオールとして、ポリプロピレングリコール（ＰＰＧ）（重量平均分子量１０００）９０重量部、１，５－ペンタンジオール５重量部、ネオペンチルグリコール５重量部を用いた。 (Manufacturing of polyurethane foam 1-3 (PU1-3))
A polyurethane foam was obtained in the same manner as in the production of polyurethane foam 1-1 (PU1-1) except for the following points.
[1] As the polyol, 90 parts by weight of polypropylene glycol (PPG) (weight average molecular weight 1000), 5 parts by weight of 1,5-pentanediol, and 5 parts by weight of neopentyl glycol were used.
（ポリウレタン発泡体２（ＰＵ２）の製造）
以下の点以外はポリウレタン発泡体１－１（ＰＵ１－１）の製造と同様にして、ポリウレタン発泡体を得た。
［１］ポリオールとして、ポリプロピレングリコール（ＰＰＧ）（重量平均分子量１０００）８５重量部、１，６－ヘキサメチレンジオール３重量部、ネオペンチルグリコール３重量部、ε－カプロラクトン９重量部を用いた。
［２］ポリイソシアネート（ポリメリックＭＤＩ、東ソー社製）をイソシアネートインデックス９０になるよう調整し投入した。 (Manufacturing of polyurethane foam 2 (PU2))
A polyurethane foam was obtained in the same manner as in the production of polyurethane foam 1-1 (PU1-1) except for the following points.
[1] As the polyol, 85 parts by weight of polypropylene glycol (PPG) (weight average molecular weight 1000), 3 parts by weight of 1,6-hexamethylenediol, 3 parts by weight of neopentyl glycol, and 9 parts by weight of ε-caprolactone were used.
[2] Polyisocyanate (Polymeric MDI, manufactured by Tosoh Corporation) was adjusted to have an isocyanate index of 90 and charged.
（ポリウレタン発泡体３－１（ＰＵ３－１）の製造）
以下の点以外はポリウレタン発泡体１－１（ＰＵ１－１）の製造と同様にして、ポリウレタン発泡体を得た。
［１］ポリオールとして、ポリプロピレングリコール（ＰＰＧ）（重量平均分子量１０００）９１重量部、ε－カプロラクトン９重量部を用いた。
［２］ポリイソシアネート（ポリメリックＭＤＩ、東ソー社製）をイソシアネートインデックス１００になるよう調整し投入した。
［３］混合する窒素ガスを調整するとともに、微細な気泡が混入した溶液を厚み５０μｍのＰＥＴセパレーター（ニッパ製、Ｖ－２）上に塗布する際の厚みを変更した（薄くした）。 (Manufacture of Polyurethane Foam 3-1 (PU3-1))
A polyurethane foam was obtained in the same manner as in the production of polyurethane foam 1-1 (PU1-1) except for the following points.
[1] As the polyol, 91 parts by weight of polypropylene glycol (PPG) (weight average molecular weight 1000) and 9 parts by weight of ε-caprolactone were used.
[2] Polyisocyanate (Polymeric MDI, manufactured by Tosoh Corporation) was adjusted to have an isocyanate index of 100 and charged.
[3] The nitrogen gas to be mixed was adjusted, and the thickness when the solution containing fine bubbles was applied onto a PET separator (manufactured by nippers, V-2) having a thickness of 50 μm was changed (thinned).
（ポリウレタン発泡体３－２（ＰＵ３－２）の製造）
以下の点以外はポリウレタン発泡体１－１（ＰＵ１－１）の製造と同様にして、ポリウレタン発泡体を得た。
［１］ポリオールとして、ポリプロピレングリコール（ＰＰＧ）（重量平均分子量１０００）９１重量部、ε－カプロラクトン９重量部を用いた。
［２］ポリイソシアネート（ポリメリックＭＤＩ、東ソー社製）をイソシアネートインデックス１００になるよう調整し投入した。 (Manufacturing of polyurethane foam 3-2 (PU3-2))
A polyurethane foam was obtained in the same manner as in the production of polyurethane foam 1-1 (PU1-1) except for the following points.
[1] As the polyol, 91 parts by weight of polypropylene glycol (PPG) (weight average molecular weight 1000) and 9 parts by weight of ε-caprolactone were used.
[2] Polyisocyanate (Polymeric MDI, manufactured by Tosoh Corporation) was adjusted to have an isocyanate index of 100 and charged.
（ポリウレタン発泡体３－３（ＰＵ３－３）の製造）
以下の点以外はポリウレタン発泡体１－１（ＰＵ１－１）の製造と同様にして、ポリウレタン発泡体を得た。
［１］ポリオールとして、ポリプロピレングリコール（ＰＰＧ）（重量平均分子量１０００）９１重量部、ε－カプロラクトン９重量部を用いた。
［２］ポリイソシアネート（ポリメリックＭＤＩ、東ソー社製）をイソシアネートインデックス１００になるよう調整し投入した。
［３］混合する窒素ガスを調整するとともに、微細な気泡が混入した溶液を厚み５０μｍのＰＥＴセパレーター（ニッパ製、Ｖ－２）上に塗布する際の厚みを変更した（厚くした）。 (Manufacturing of polyurethane foam 3-3 (PU3-3))
A polyurethane foam was obtained in the same manner as in the production of polyurethane foam 1-1 (PU1-1) except for the following points.
[1] As the polyol, 91 parts by weight of polypropylene glycol (PPG) (weight average molecular weight 1000) and 9 parts by weight of ε-caprolactone were used.
[2] Polyisocyanate (Polymeric MDI, manufactured by Tosoh Corporation) was adjusted to have an isocyanate index of 100 and charged.
[3] The nitrogen gas to be mixed was adjusted, and the thickness when the solution mixed with fine bubbles was applied onto a PET separator (manufactured by nippers, V-2) having a thickness of 50 μm was changed (thickened).
（ポリウレタン発泡体４（ＰＵ４）の製造）
以下の点以外はポリウレタン発泡体１－１（ＰＵ１－１）の製造と同様にして、ポリウレタン発泡体を得た。
［１］ポリオールとして、ポリプロピレングリコール（ＰＰＧ）（重量平均分子量１０００）９０重量部、１，５－ペンタンジオール５重量部、１，６－ヘキサメチレンジオール５重量部を用いた。
［２］ポリイソシアネート（２核体モノメリックＭＤＩ、東ソー社製）をイソシアネートインデックス７５になるよう調整し投入した。 (Manufacturing of Polyurethane Foam 4 (PU4))
A polyurethane foam was obtained in the same manner as in the production of polyurethane foam 1-1 (PU1-1) except for the following points.
[1] As the polyol, 90 parts by weight of polypropylene glycol (PPG) (weight average molecular weight 1000), 5 parts by weight of 1,5-pentanediol, and 5 parts by weight of 1,6-hexamethylenediol were used.
[2] Polyisocyanate (dinuclear monomeric MDI, manufactured by Tosoh Corporation) was adjusted to have an isocyanate index of 75 and charged.
（ポリウレタン発泡体５（ＰＵ５）の製造）
以下の点以外はポリウレタン発泡体１－１（ＰＵ１－１）の製造と同様にして、ポリウレタン発泡体を得た。
［１］ポリオールとして、ポリプロピレングリコール（ＰＰＧ）（重量平均分子量１０００）９０重量部、１，６－ヘキサメチレンジオール１０重量部を用いた。
［２］ポリイソシアネート（２核体モノメリックＭＤＩ、東ソー社製）をイソシアネートインデックス９５になるよう調整し投入した。 (Manufacturing of Polyurethane Foam 5 (PU5))
A polyurethane foam was obtained in the same manner as in the production of polyurethane foam 1-1 (PU1-1) except for the following points.
[1] As the polyol, 90 parts by weight of polypropylene glycol (PPG) (weight average molecular weight 1000) and 10 parts by weight of 1,6-hexamethylenediol were used.
[2] Polyisocyanate (dinuclear monomeric MDI, manufactured by Tosoh Corporation) was adjusted to have an isocyanate index of 95 and charged.
（ポリウレタン発泡体６（ＰＵ６）の製造）
以下の点以外はポリウレタン発泡体１－１（ＰＵ１－１）の製造と同様にして、ポリウレタン発泡体を得た。
［１］ポリオールとして、ポリプロピレングリコール（ＰＰＧ）（重量平均分子量１０００）９０重量部、１，５－ペンタンジオール１０重量部を用いた。
［２］ポリイソシアネート（２核体モノメリックＭＤＩ、東ソー社製）をイソシアネートインデックス７０になるよう調整し投入した。 (Manufacturing of polyurethane foam 6 (PU6))
A polyurethane foam was obtained in the same manner as in the production of polyurethane foam 1-1 (PU1-1) except for the following points.
[1] As the polyol, 90 parts by weight of polypropylene glycol (PPG) (weight average molecular weight 1000) and 10 parts by weight of 1,5-pentanediol were used.
[2] Polyisocyanate (dinuclear monomeric MDI, manufactured by Tosoh Corporation) was adjusted to have an isocyanate index of 70 and charged.
（ポリウレタン発泡体７（ＰＵ７）の製造）
以下の点以外はポリウレタン発泡体１－１（ＰＵ１－１）の製造と同様にして、ポリウレタン発泡体を得た。
［１］ポリオールとして、ポリプロピレングリコール（ＰＰＧ）（重量平均分子量１０００）９１重量部、ε－カプロラクトン９重量部を用いた。
［２］ポリイソシアネート（ポリメリックＭＤＩ、東ソー社製）をイソシアネートインデックス１１０になるよう調整し投入した。 (Manufacturing of Polyurethane Foam 7 (PU7))
A polyurethane foam was obtained in the same manner as in the production of polyurethane foam 1-1 (PU1-1) except for the following points.
[1] As the polyol, 91 parts by weight of polypropylene glycol (PPG) (weight average molecular weight 1000) and 9 parts by weight of ε-caprolactone were used.
[2] Polyisocyanate (Polymeric MDI, manufactured by Tosoh Corporation) was adjusted to have an isocyanate index of 110 and charged.
（ポリウレタン発泡体８（ＰＵ８）の製造）
以下の点以外はポリウレタン発泡体３－１（ＰＵ３－１）の製造と同様にして、ポリウレタン発泡体を得た。
［１］ポリオールとして、ポリプロピレングリコール（ＰＰＧ）（重量平均分子量１０００）９１重量部、ε－カプロラクトン９重量部を用いた。
［２］ポリイソシアネート（ポリメリックＭＤＩ、東ソー社製）をイソシアネートインデックス８５になるよう調整し投入した。 (Manufacturing of Polyurethane Foam 8 (PU8))
A polyurethane foam was obtained in the same manner as in the production of polyurethane foam 3-1 (PU3-1) except for the following points.
[1] As the polyol, 91 parts by weight of polypropylene glycol (PPG) (weight average molecular weight 1000) and 9 parts by weight of ε-caprolactone were used.
[2] Polyisocyanate (Polymeric MDI, manufactured by Tosoh Corporation) was adjusted to have an isocyanate index of 85 and charged.
（ポリウレタン発泡体９（ＰＵ９）の製造）
以下の点以外はポリウレタン発泡体８（ＰＵ８）の製造と同様にして、ポリウレタン発泡体を得た。
［１］ポリイソシアネート（ポリメリックＭＤＩ、東ソー社製）をイソシアネートインデックス９０になるよう調整し投入した。 (Manufacture of Polyurethane Foam 9 (PU9))
A polyurethane foam was obtained in the same manner as in the production of the polyurethane foam 8 (PU8) except for the following points.
[1] Polyisocyanate (Polymeric MDI, manufactured by Tosoh Corporation) was adjusted to have an isocyanate index of 90 and charged.
（ポリウレタン発泡体１０（ＰＵ１０）の製造）
以下の点以外はポリウレタン発泡体１－１（ＰＵ１－１）の製造と同様にして、ポリウレタン発泡体を得た。
［１］ポリイソシアネート（２核体モノメリックＭＤＩ、東ソー社製）をイソシアネートインデックス７０になるよう調整し投入した。
［２］混合する窒素ガスを調整するとともに、微細な気泡が混入した溶液を厚み５０μｍのＰＥＴセパレーター（ニッパ製、Ｖ－２）上に塗布する際の厚みを変更した（厚くした）。 (Manufacturing of Polyurethane Foam 10 (PU10))
A polyurethane foam was obtained in the same manner as in the production of polyurethane foam 1-1 (PU1-1) except for the following points.
[1] Polyisocyanate (dinuclear monomeric MDI, manufactured by Tosoh Corporation) was adjusted to have an isocyanate index of 70 and charged.
[2] The nitrogen gas to be mixed was adjusted, and the thickness when the solution mixed with fine bubbles was applied onto a PET separator (manufactured by nippers, V-2) having a thickness of 50 μm was changed (thickened).
（ポリウレタン発泡体１１（ＰＵ１１）の製造）
以下の点以外はポリウレタン発泡体１－１（ＰＵ１－１）の製造と同様にして、ポリウレタン発泡体を得た。
［１］ポリオールとして、ポリプロピレングリコール（ＰＰＧ）（重量平均分子量１０００）３０重量部、ポリプロピレングリコール（ＰＰＧ）（重量平均分子量３１００）６０重量部、１，５－ペンタンジオール１０重量部を用いた。
［２］ポリイソシアネート（ポリメリックＭＤＩ、東ソー社製）をイソシアネートインデックス６５になるよう調整し投入した。
［３］混合する窒素ガスを調整するとともに、微細な気泡が混入した溶液を厚み５０μｍのＰＥＴセパレーター（ニッパ製、Ｖ－２）上に塗布する際の厚みを変更した（厚くした）。 (Manufacturing of Polyurethane Foam 11 (PU11))
A polyurethane foam was obtained in the same manner as in the production of polyurethane foam 1-1 (PU1-1) except for the following points.
[1] As the polyol, 30 parts by weight of polypropylene glycol (PPG) (weight average molecular weight 1000), 60 parts by weight of polypropylene glycol (PPG) (weight average molecular weight 3100), and 10 parts by weight of 1,5-pentanediol were used.
[2] Polyisocyanate (Polymeric MDI, manufactured by Tosoh Corporation) was adjusted to have an isocyanate index of 65 and charged.
[3] The nitrogen gas to be mixed was adjusted, and the thickness when the solution mixed with fine bubbles was applied onto a PET separator (manufactured by nippers, V-2) having a thickness of 50 μm was changed (thickened).
（ポリウレタン発泡体１２（ＰＵ１２）の製造）
以下の点以外はポリウレタン発泡体１－１（ＰＵ１－１）の製造と同様にして、ポリウレタン発泡体を得た。
［１］ポリオールとして、ポリプロピレングリコール（ＰＰＧ）（重量平均分子量１０００）２０重量部、ポリプロピレングリコール（ＰＰＧ）（重量平均分子量３１００）７０重量部、１，５－ペンタンジオール１０重量部を用いた。
［２］ポリイソシアネート（ポリメリックＭＤＩ、東ソー社製）をイソシアネートインデックス６５になるよう調整し投入した。
［３］混合する窒素ガスを調整するとともに、微細な気泡が混入した溶液を厚み５０μｍのＰＥＴセパレーター（ニッパ製、Ｖ－２）上に塗布する際の厚みを変更した（厚くした）。 (Manufacture of Polyurethane Foam 12 (PU12))
A polyurethane foam was obtained in the same manner as in the production of polyurethane foam 1-1 (PU1-1) except for the following points.
[1] As the polyol, 20 parts by weight of polypropylene glycol (PPG) (weight average molecular weight 1000), 70 parts by weight of polypropylene glycol (PPG) (weight average molecular weight 3100), and 10 parts by weight of 1,5-pentanediol were used.
[2] Polyisocyanate (Polymeric MDI, manufactured by Tosoh Corporation) was adjusted to have an isocyanate index of 65 and charged.
[3] The nitrogen gas to be mixed was adjusted, and the thickness when the solution mixed with fine bubbles was applied onto a PET separator (manufactured by nippers, V-2) having a thickness of 50 μm was changed (thickened).
（ポリエチレン発泡体１（ＰＥ１））
ポリエチレン発泡体として、ＸＬＩＭ＃１５００３（積水化学工業社製）を用いた。 (Polyethylene foam 1 (PE1))
XLIM # 15003 (manufactured by Sekisui Chemical Co., Ltd.) was used as the polyethylene foam.
（粘着剤Ｉの製造（ラジカル重合））
温度計、攪拌機、冷却管を備えた反応器に酢酸エチル５２重量部を入れて、窒素置換した後、反応器を加熱して還流を開始した。酢酸エチルが沸騰してから、３０分後に重合開始剤としてアゾビスイソブチロニトリル０．０８重量部を投入した。ここにモノマー混合物（アクリル酸ブチル（ＢＡ）６０重量部、アクリル酸２－エチルへキシル（２ＥＨＡ）３６．９重量部、アクリル酸（ＡＡｃ）３重量部、及び、アクリル酸２－ヒドロキシエチル（２ＨＥＡ）０．１重量部）を１時間３０分かけて、均等かつ徐々に滴下し反応させた。滴下終了３０分後にアゾビスイソブチロニトリル０．１重量部を添加し、更に５時間重合反応させ、反応器内に酢酸エチルを加えて希釈しながら冷却することにより、アクリル共重合体含有溶液を得た。 (Production of Adhesive I (Radical Polymerization))
52 parts by weight of ethyl acetate was placed in a reactor equipped with a thermometer, a stirrer, and a cooling tube to replace with nitrogen, and then the reactor was heated to start reflux. Thirty minutes after the ethyl acetate boiled, 0.08 parts by weight of azobisisobutyronitrile was added as a polymerization initiator. Here, a monomer mixture (60 parts by weight of butyl acrylate (BA), 36.9 parts by weight of 2-ethylhexyl acrylate (2EHA), 3 parts by weight of acrylic acid (AAc), and 2-hydroxyethyl acrylate (2HEA) ) 0.1 part by weight) was added dropwise evenly and gradually over 1 hour and 30 minutes to react. 30 minutes after the completion of the dropping, 0.1 part by weight of azobisisobutyronitrile was added, the polymerization reaction was further carried out for 5 hours, and ethyl acetate was added to the reactor to cool the solution while diluting the solution. Got
得られたアクリル共重合体の重量平均分子量（Ｍｗ）及び分子量分布（Ｍｗ／Ｍｎ）を求めた。具体的には、得られたアクリル共重合体含有溶液をテトラヒドロフラン（ＴＨＦ）によって５０倍希釈して得られた希釈液をフィルター（材質：ポリテトラフルオロエチレン、ポア径：０．２μｍ）で濾過した。得られた濾液をゲルパミエーションクロマトグラフ（Ｗａｔｅｒｓ社製、２６９０　Ｓｅｐａｒａｔｉｏｎｓ　Ｍｏｄｅｌ）に供給して、サンプル流量１ミリリットル／ｍｉｎ、カラム温度４０℃の条件でＧＰＣ測定を行い、アクリル共重合体のポリスチレン換算分子量を測定して、重量平均分子量及び分子量分布（Ｍｗ／Ｍｎ）を求めた。重量平均分子量は１００万、分子量分布（Ｍｗ／Ｍｎ）は２．６であった。カラムとしてはＧＰＣ　ＫＦ－８０６Ｌ（昭和電工社製）を用い、検出器としては示差屈折計を用いた。 The weight average molecular weight (Mw) and the molecular weight distribution (Mw / Mn) of the obtained acrylic copolymer were determined. Specifically, the obtained acrylic copolymer-containing solution was diluted 50-fold with tetrahydrofuran (THF), and the obtained diluted solution was filtered through a filter (material: polytetrafluoroethylene, pore diameter: 0.2 μm). .. The obtained filtrate was supplied to a gel permeation chromatograph (manufactured by Waters, 2690 Separations Model), and GPC measurement was performed under the conditions of a sample flow rate of 1 ml / min and a column temperature of 40 ° C. to convert the acrylic copolymer into polystyrene. The molecular weight was measured to determine the weight average molecular weight and the molecular weight distribution (Mw / Mn). The weight average molecular weight was 1 million, and the molecular weight distribution (Mw / Mn) was 2.6. A GPC KF-806L (manufactured by Showa Denko KK) was used as the column, and a differential refractometer was used as the detector.
得られたアクリル共重合体含有溶液の不揮発分１００重量部に対して酢酸エチルを加えて攪拌し、架橋剤（イソシアネート系架橋剤、コロネートＬ－５５Ｅ、東ソー社製）５重量部、粘着付与剤の合計３０重量部を添加して攪拌し、不揮発分３０重量％の粘着剤Ｉを得た。粘着付与剤としては、水添ロジン系樹脂（軟化点１００℃、水酸基価４０ｍｇＫＯＨ／ｇ）１０重量部、ロジンエステル系樹脂（軟化点１５０℃、水酸基価４０ｍｇＫＯＨ／ｇ）１０重量部、テルペンフェノール系樹脂（軟化点１５０℃、水酸基価４０ｍｇＫＯＨ／ｇ）１０重量部を用いた。 Ethyl acetate was added to 100 parts by weight of the non-volatile content of the obtained acrylic copolymer-containing solution and stirred, and 5 parts by weight of a cross-linking agent (isocyanate-based cross-linking agent, Coronate L-55E, manufactured by Toso Co., Ltd.) and a tackifier were added. A total of 30 parts by weight was added and stirred to obtain a pressure-sensitive adhesive I having a non-volatile content of 30% by weight. As the tackifier, 10 parts by weight of a hydrogenated rosin resin (softening point 100 ° C., hydroxyl value 40 mgKOH / g), 10 parts by weight of a rosin ester resin (softening point 150 ° C., hydroxyl value 40 mgKOH / g), terpene phenol type. 10 parts by weight of a resin (softening point 150 ° C., hydroxyl value 40 mgKOH / g) was used.
（実施例１～１２、比較例１～５）
支持層１（樹脂シート）に粘着剤Ｉを塗布し、１００℃で５分間乾燥させることにより、厚み２０μｍの粘着剤層１を形成した。この粘着剤層１に発泡体基材の片面を圧着させ、支持層１と発泡体基材とが粘着剤層１を介して積層された積層体を作製した。支持層１（樹脂シート）としては、ポリエチレンテレフタレート（ＰＥＴ）（Ｘ３０、東レ社製、厚み５０μｍ）を用いた。次いで、発泡体基材のもう一方の面に支持層２（樹脂シート）を熱融着させ、支持層１、粘着剤層１、発泡体基材、支持層２がこの順に積層された積層体を作製した。支持層２（樹脂シート）としては、アクリル系樹脂（ＬＡ２２５０、クラレ社製、厚み５０μｍ）又はウレタン系ブロック共重合体（ＴＰＵ）からなるシート（１１９８ＡＴＲ、ＢＡＳＦ社製、厚み２０μｍ）を用いた。
次いで、厚み１５０μｍの離型紙を用意し、この離型紙の離型処理面に粘着剤Ｉを塗布し、１００℃で５分間乾燥させることにより、厚み５０μｍ、５５μｍ又は６０μｍの粘着剤層２を形成した。この粘着剤層２を、発泡体基材に積層された支持層１（樹脂シート）の表面と貼り合わせた。次いで、同様の要領で、発泡体基材の反対の支持層２（樹脂シート）の表面にも、上記粘着剤層２と同じ構成の粘着剤層３を貼り合わせた。その後、４０℃で４８時間加熱することで養生を行った。これにより、離型紙で覆われた両面粘着テープを得た。
なお、支持層２（樹脂シート）の引張弾性率は、それぞれ１０ＭＰａ、１０８ＭＰａであった。 (Examples 1 to 12, Comparative Examples 1 to 5)
The pressure-sensitive adhesive I was applied to the support layer 1 (resin sheet) and dried at 100 ° C. for 5 minutes to form the pressure-sensitive adhesive layer 1 having a thickness of 20 μm. One side of the foam base material was pressure-bonded to the pressure-sensitive adhesive layer 1 to prepare a laminated body in which the support layer 1 and the foam base material were laminated via the pressure-sensitive adhesive layer 1. As the support layer 1 (resin sheet), polyethylene terephthalate (PET) (X30, manufactured by Toray Industries, Inc., thickness 50 μm) was used. Next, the support layer 2 (resin sheet) is heat-sealed to the other surface of the foam base material, and the support layer 1, the pressure-sensitive adhesive layer 1, the foam base material, and the support layer 2 are laminated in this order. Was produced. As the support layer 2 (resin sheet), a sheet made of an acrylic resin (LA2250, manufactured by Kuraray, thickness 50 μm) or a urethane-based block copolymer (TPU) (1198ATR, manufactured by BASF, thickness 20 μm) was used.
Next, a release paper having a thickness of 150 μm is prepared, the adhesive I is applied to the release-treated surface of the release paper, and the adhesive layer 2 is formed at 100 ° C. for 5 minutes to form an adhesive layer 2 having a thickness of 50 μm, 55 μm or 60 μm. did. The pressure-sensitive adhesive layer 2 was bonded to the surface of the support layer 1 (resin sheet) laminated on the foam base material. Next, in the same manner, the pressure-sensitive adhesive layer 3 having the same structure as the pressure-sensitive adhesive layer 2 was bonded to the surface of the support layer 2 (resin sheet) opposite to the foam base material. Then, it was cured by heating at 40 degreeC for 48 hours. As a result, a double-sided adhesive tape covered with a release paper was obtained.
The tensile elastic modulus of the support layer 2 (resin sheet) was 10 MPa and 108 MPa, respectively.
得られた両面粘着テープを５０ｍｍ×１００ｍｍの平面長方形状に裁断して試験片を作製し、試験片を酢酸エチル中に２３℃にて２４時間浸漬した後、酢酸エチルから取り出して、１１０℃の条件下で１時間乾燥させた。乾燥後の試験片の重量を測定し、下記式（５）を用いて粘着剤層のゲル分率を算出したところ、粘着剤層のゲル分率は４２重量％であった。
ゲル分率（重量％）＝１００×（Ｗ２－Ｗ０）／（Ｗ１－Ｗ０）　　　（５）
（Ｗ０：基材の重量、Ｗ１：浸漬前の試験片の重量、Ｗ２：浸漬、乾燥後の試験片の重量） The obtained double-sided adhesive tape was cut into a flat rectangular shape of 50 mm × 100 mm to prepare a test piece, and the test piece was immersed in ethyl acetate at 23 ° C. for 24 hours, then taken out from ethyl acetate and taken out at 110 ° C. It was dried under the conditions for 1 hour. The weight of the test piece after drying was measured, and the gel fraction of the pressure-sensitive adhesive layer was calculated using the following formula (5). As a result, the gel fraction of the pressure-sensitive adhesive layer was 42% by weight.
Gel fraction (% by weight) = 100 x (W 2- W 0 ) / (W 1- W 0 ) (5)
(W 0 : Weight of base material, W 1 : Weight of test piece before immersion, W 2 : Weight of test piece after immersion and drying)
＜評価＞
実施例、比較例で得られた両面粘着テープについて以下の評価を行った。結果を表１～２に示した。 <Evaluation>
The double-sided adhesive tapes obtained in Examples and Comparative Examples were evaluated as follows. The results are shown in Tables 1 and 2.
（１）リワーク（層間引裂き試験）
図２に、両面粘着テープの層間引裂き試験を示す模式図を示す。図２（ａ）は正面図、図２（ｂ）は側面図である。両面粘着テープのサイズ５０ｍｍ×５ｍｍの試験片２、及び、２枚のサイズ１００ｍｍ×２０ｍｍ、厚さ２ｍｍのＰＣ板１を図２に示すように積層した。この積層体を５ｋｇ、１０秒の条件で重しを用いて圧着した後、２４時間放置し、試験片２を介して２枚のＰＣ板１を貼り合わせた引裂き試験用サンプルを作製した。この引裂き試験用サンプルの一方のＰＣ板を固定した後、ステンレス製の針金３（０．３φ、ＴＲＵＳＣＯ社製「ＴＹＷＳ－０３」）を試験片２の下から引っ掛け、図２の矢印方向に３００ｍｍ／ｍｉｎの条件で引っ張った。試験片２の基材層間が針金３により引裂かれる際の試験力を測定した。試験力が１０Ｎ／５ｍｍ未満であった場合を◎、１０Ｎ／５ｍｍ以上１５Ｎ／５ｍｍ未満であった場合を〇、１５Ｎ／５ｍｍ以上であった場合を×と示した。 (1) Rework (interlayer tear test)
FIG. 2 shows a schematic view showing an interlayer tear test of the double-sided adhesive tape. FIG. 2A is a front view, and FIG. 2B is a side view. A test piece 2 having a size of 50 mm × 5 mm and two PC plates 1 having a size of 100 mm × 20 mm and a thickness of 2 mm of double-sided adhesive tape were laminated as shown in FIG. This laminate was crimped with a weight under the conditions of 5 kg and 10 seconds, and then left for 24 hours to prepare a tear test sample in which two PC plates 1 were bonded via a test piece 2. After fixing one PC plate of this tear test sample, a stainless steel wire 3 (0.3φ, TRUSCO "TYWS-03") is hooked from under the test piece 2 and 300 mm in the direction of the arrow in FIG. It was pulled under the condition of / min. The test force when the base material layers of the test piece 2 were torn by the wire 3 was measured. The case where the test force was less than 10 N / 5 mm was indicated by ⊚, the case where the test force was 10 N / 5 mm or more and less than 15 N / 5 mm was indicated by 〇, and the case where the test force was 15 N / 5 mm or more was indicated by ×.
（２）耐落下衝撃（タンブル試験）
図３に、両面粘着テープのタンブル試験用サンプルを示す模式図を示す。両面粘着テープの長辺２３ｍｍ×短辺１３．３ｍｍ、幅３．２ｍｍの額縁状の試験片６を、サイズ５５ｍｍ×６５ｍｍ、厚さ１０ｍｍ、重さ４２ｇのＰＭＭＡ板５とサイズ７０ｍｍ×１３０ｍｍ、厚さ２ｍｍ、重さ１３７ｇのＳＵＳ板４とで挟み、図３に示すように積層した。この積層体を５ｋｇ、１０秒の条件で重しを用いて圧着した後、２４時間放置し、試験片６を介してＰＭＭＡ板５とＳＵＳ板４とを貼り合わせたタンブル試験用サンプルを作製した。タンブル試験用サンプルをタンブル試験機（新栄電子計測器社製、ＴＤＲ－１０００Ａ－ＳＣ０１）に入れ、１０回落下／ｍｉｎの頻度で様々な角度からの落下衝撃を繰り返し与えた。両面粘着テープが破断してタンブル試験用サンプルが分離するまでの落下回数を測定した。落下回数が３０回以上であった場合を◎、１０回以上３０回未満であった場合を〇、１０回未満であった場合を×と示した。 (2) Drop impact resistance (tumble test)
FIG. 3 shows a schematic view showing a sample for a tumble test of the double-sided adhesive tape. A frame-shaped test piece 6 having a long side of 23 mm, a short side of 13.3 mm, and a width of 3.2 mm of double-sided adhesive tape, and a PMMA plate 5 having a size of 55 mm x 65 mm, a thickness of 10 mm, and a weight of 42 g, and a size of 70 mm x 130 mm, thickness. It was sandwiched between a SUS plate 4 having a size of 2 mm and a weight of 137 g, and laminated as shown in FIG. This laminate was crimped with a weight under the conditions of 5 kg and 10 seconds, and then left for 24 hours to prepare a sample for tumble test in which the PMMA plate 5 and the SUS plate 4 were bonded to each other via the test piece 6. .. The tumble test sample was placed in a tumble tester (TDR-1000A-SC01 manufactured by Shinei Denshi Keiki Co., Ltd.), and a drop impact from various angles was repeatedly applied at a frequency of 10 drops / min. The number of drops until the double-sided adhesive tape broke and the sample for tumble test was separated was measured. The case where the number of drops was 30 or more was indicated by ⊚, the case where the number of drops was 10 or more and less than 30 was indicated by 0, and the case where the number of drops was less than 10 was indicated by ×.
（３）表示ムラ（面うねり試験）
図４に、両面粘着テープの面うねり試験を示す模式図を示す。図４（ａ）は上面図、図４（ｂ）は断面図である。サイズ２５６ｍｍ×１８２ｍｍ、厚さ４ｍｍのガラス板１０の上に、幅１５ｍｍ、厚さ５０μｍの片面黒色遮光テープ８を１５ｍｍ間隔を空けて積層し段差を作った。同様にガラス板１０の上に、幅１５ｍｍ、厚さ１００μｍの片面黒色遮光テープ９を積層し段差を作った。これらの段差の上から、両面粘着テープの幅１０ｍｍの試験片７をガラス板１０の４辺に積層した。試験片７の上にサイズ２５６ｍｍ×１８２ｍｍ、厚さ１ｍｍのガラス板１２を積層し、試験片７を介してガラス板１０とガラス板１２とを貼り合わせた。更にガラス板１２の上に厚さ１００μｍの片面黒色遮光テープ１３を積層し、面うねり試験用サンプルを得た。ＪＩＳ　Ｂ０６０１：２００１に準拠して、面うねり試験用サンプルにおける２１０ｍｍ×１０５ｍｍの測定領域１１に対して、レーザー顕微鏡（キーエンス社製、ＶＲ－３０００型）を用いて表面粗さの最大高さＳｚを測定した。最大高さＳｚが１２０μｍ未満であった場合を◎、１２０μｍ以上２００μｍ未満であった場合を〇、２００μｍ以上であった場合を×と示した。 (3) Display unevenness (surface swell test)
FIG. 4 shows a schematic view showing a surface waviness test of the double-sided adhesive tape. FIG. 4A is a top view and FIG. 4B is a cross-sectional view. A single-sided black light-shielding tape 8 having a width of 15 mm and a thickness of 50 μm was laminated on a glass plate 10 having a size of 256 mm × 182 mm and a thickness of 4 mm at intervals of 15 mm to form a step. Similarly, a single-sided black light-shielding tape 9 having a width of 15 mm and a thickness of 100 μm was laminated on the glass plate 10 to form a step. From above these steps, test pieces 7 having a width of 10 mm of double-sided adhesive tape were laminated on the four sides of the glass plate 10. A glass plate 12 having a size of 256 mm × 182 mm and a thickness of 1 mm was laminated on the test piece 7, and the glass plate 10 and the glass plate 12 were bonded to each other via the test piece 7. Further, a single-sided black light-shielding tape 13 having a thickness of 100 μm was laminated on the glass plate 12 to obtain a sample for a surface waviness test. According to JIS B0601: 2001, the maximum height Sz of the surface roughness is determined by using a laser microscope (manufactured by KEYENCE, VR-3000 type) for the measurement area 11 of 210 mm × 105 mm in the sample for surface waviness test. It was measured. The case where the maximum height Sz was less than 120 μm was indicated by ⊚, the case where the maximum height Sz was 120 μm or more and less than 200 μm was indicated by ◯, and the case where the maximum height Sz was 200 μm or more was indicated by ×.
Figure JPOXMLDOC01-appb-T000001
Figure JPOXMLDOC01-appb-T000001
Figure JPOXMLDOC01-appb-T000002
Figure JPOXMLDOC01-appb-T000002
本発明によれば、耐落下衝撃性に優れ、ディスプレイ装置の表示ムラを低減することができ、被着体から剥がす際には発泡体基材を容易に引裂くことができる両面粘着テープを提供することができる。 According to the present invention, there is provided a double-sided adhesive tape which is excellent in drop impact resistance, can reduce display unevenness of a display device, and can easily tear a foam base material when peeled from an adherend. can do.
１　　ＰＣ板
２　　試験片（両面粘着テープ）
３　　針金
４　　ＳＵＳ板
５　　ＰＭＭＡ板
６　　額縁状の試験片（両面粘着テープ）
７　　試験片（両面粘着テープ）
８　　片面黒色遮光テープ（幅１５ｍｍ、厚さ５０μｍ）
９　　片面黒色遮光テープ（幅１５ｍｍ、厚さ１００μｍ）
１０　ガラス板
１１　測定領域
１２　ガラス板
１３　片面黒色遮光テープ
１８　試験片（両面粘着テープ）
１９　ＳＵＳ板 1 PC board 2 Test piece (double-sided adhesive tape)
3 Wire 4 SUS plate 5 PMMA plate 6 Frame-shaped test piece (double-sided adhesive tape)
7 Test piece (double-sided adhesive tape)
8 Single-sided black light-shielding tape (width 15 mm, thickness 50 μm)
9 Single-sided black light-shielding tape (width 15 mm, thickness 100 μm)
10 Glass plate 11 Measurement area 12 Glass plate 13 Single-sided black light-shielding tape 18 Test piece (double-sided adhesive tape)
19 SUS board

Claims (13)

  1. 発泡体基材と、前記発泡体基材の両側に積層された粘着剤層とを有する両面粘着テープであって、
    前記発泡体基材は、気泡体積分率が４０体積％以上７５体積％以下であり、せん断破断強度が２００Ｎ／ｉｎｃｈ２以上５００Ｎ／ｉｎｃｈ２以下である
    ことを特徴とする両面粘着テープ。     A double-sided adhesive tape having a foam base material and pressure-sensitive adhesive layers laminated on both sides of the foam base material.
    The foam base material is a double-sided adhesive tape having a bubble volume fraction of 40% by volume or more and 75% by volume or less and a shear breaking strength of 200 N / inch 2 or more and 500 N / inch 2 or less.
  2. 発泡体基材は、２５％圧縮強度が０．０１５ＭＰａ以上０．０８ＭＰａ以下であることを特徴とする請求項１記載の両面粘着テープ。 The double-sided adhesive tape according to claim 1, wherein the foam base material has a 25% compression strength of 0.015 MPa or more and 0.08 MPa or less.
  3. 発泡体基材は、気泡の長径分布の平均が５５μｍ以下であることを特徴とする請求項１又は２記載の両面粘着テープ。 The double-sided adhesive tape according to claim 1 or 2, wherein the foam base material has an average major axis distribution of bubbles of 55 μm or less.
  4. 発泡体基材は、気泡の長径分布の標準偏差が３０μｍ以下であることを特徴とする請求項１、２又は３記載の両面粘着テープ。 The double-sided adhesive tape according to claim 1, 2 or 3, wherein the foam base material has a standard deviation of the major axis distribution of bubbles of 30 μm or less.
  5. 発泡体基材は、気泡の扁平率が０．２以下であることを特徴とする請求項１、２、３又は４記載の両面粘着テープ。 The double-sided adhesive tape according to claim 1, 2, 3 or 4, wherein the foam base material has a flatness of bubbles of 0.2 or less.
  6. 発泡体基材は、気泡のアスペクト比が１．５以下であることを特徴とする請求項１、２、３、４又は５記載の両面粘着テープ。 The double-sided adhesive tape according to claim 1, 2, 3, 4 or 5, wherein the foam base material has an aspect ratio of bubbles of 1.5 or less.
  7. 発泡体基材は、ポリウレタン発泡体であり、気泡の連泡率が９５体積％以下であることを特徴とする請求項１、２、３、４、５又は６記載の両面粘着テープ。 The double-sided adhesive tape according to claim 1, 2, 3, 4, 5 or 6, wherein the foam base material is a polyurethane foam and the continuous foam ratio of bubbles is 95% by volume or less.
  8. 発泡体基材は、厚みが１００μｍ以上１０００μｍ以下であることを特徴とする請求項１、２、３、４、５、６又は７記載の両面粘着テープ。 The double-sided adhesive tape according to claim 1, 2, 3, 4, 5, 6 or 7, wherein the foam base material has a thickness of 100 μm or more and 1000 μm or less.
  9. 粘着剤層は、アクリル共重合体及び粘着付与剤を含有するアクリル粘着剤からなり、ゲル分率が１重量％以上９０重量％以下であり、
    前記アクリル共重合体は、水酸基を含有し、重量平均分子量が３０万以上２００万以下、分子量分布（Ｍｗ／Ｍｎ）が１．０５以上５．０以下であり、
    前記粘着付与剤は、水酸基を含有するロジン系樹脂又は水酸基を含有するテルペン系樹脂であり、軟化温度が７０℃以上１７０℃以下、水酸基価が２５以上１６０以下である
    ことを特徴とする請求項１、２、３、４、５、６、７又は８記載の両面粘着テープ。     The pressure-sensitive adhesive layer is composed of an acrylic pressure-sensitive adhesive containing an acrylic copolymer and a pressure-sensitive adhesive, and has a gel content of 1% by weight or more and 90% by weight or less.
    The acrylic copolymer contains a hydroxyl group, has a weight average molecular weight of 300,000 or more and 2 million or less, and has a molecular weight distribution (Mw / Mn) of 1.05 or more and 5.0 or less.
    The tackifier is a rosin-based resin containing a hydroxyl group or a terpene-based resin containing a hydroxyl group, and is characterized by having a softening temperature of 70 ° C. or higher and 170 ° C. or lower and a hydroxyl group value of 25 or higher and 160 or lower. The double-sided adhesive tape according to 1, 2, 3, 4, 5, 6, 7 or 8.
  10. 更に、発泡体基材の少なくとも片側に樹脂シートを有し、前記樹脂シートの厚みが１０μｍ以上１００μｍ以下であることを特徴とする請求項１、２、３、４、５、６、７、８又は９記載の両面粘着テープ。 Further, claims 1, 2, 3, 4, 5, 6, 7, 8 are characterized in that a resin sheet is provided on at least one side of the foam base material, and the thickness of the resin sheet is 10 μm or more and 100 μm or less. Or the double-sided adhesive tape according to 9.
  11. 発泡体基材の第１の面に積層された第１の樹脂シートと、発泡体基材の第２の面に積層された第２の樹脂シートとを有し、前記第１の樹脂シート及び前記第２の樹脂シートからなる群より選択される少なくとも一方は、熱可塑性樹脂から構成される樹脂シートであることを特徴とする請求項１、２、３、４、５、６、７、８、９又は１０記載の両面粘着テープ。 It has a first resin sheet laminated on the first surface of the foam base material and a second resin sheet laminated on the second surface of the foam base material, and the first resin sheet and Claim 1, 2, 3, 4, 5, 6, 7, 8 characterized in that at least one selected from the group consisting of the second resin sheet is a resin sheet composed of a thermoplastic resin. , 9 or 10. The double-sided adhesive tape according to 10.
  12. 粘着剤層の厚みが２０μｍ以上１００μｍ以下であることを特徴とする請求項１、２、３、４、５、６、７、８、９、１０又は１１記載の両面粘着テープ。 The double-sided adhesive tape according to claim 1, 2, 3, 4, 5, 6, 7, 8, 9, 10 or 11, wherein the thickness of the pressure-sensitive adhesive layer is 20 μm or more and 100 μm or less.
  13. 両面粘着テープの厚みが１００μｍ以上１２００μｍ以下であることを特徴とする請求項１、２、３、４、５、６、７、８、９、１０、１１又は１２記載の両面粘着テープ。 The double-sided adhesive tape according to claim 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11 or 12, wherein the thickness of the double-sided adhesive tape is 100 μm or more and 1200 μm or less.
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