CN117561313A - Double-sided adhesive sheet - Google Patents

Double-sided adhesive sheet Download PDF

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Publication number
CN117561313A
CN117561313A CN202280044676.3A CN202280044676A CN117561313A CN 117561313 A CN117561313 A CN 117561313A CN 202280044676 A CN202280044676 A CN 202280044676A CN 117561313 A CN117561313 A CN 117561313A
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CN
China
Prior art keywords
double
mass
meth
adhesive sheet
acrylate
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CN202280044676.3A
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Chinese (zh)
Inventor
西胁匡崇
井本荣一
加藤直宏
山元健一
渡边茂树
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Nitto Denko Corp
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Nitto Denko Corp
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Priority claimed from JP2022039920A external-priority patent/JP2023008796A/en
Application filed by Nitto Denko Corp filed Critical Nitto Denko Corp
Priority claimed from PCT/JP2022/024105 external-priority patent/WO2023282009A1/en
Publication of CN117561313A publication Critical patent/CN117561313A/en
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Abstract

The present invention provides a double-sided adhesive sheet having excellent impact resistance and high shear adhesive force. The double-sided adhesive sheet 1 is a double-sided adhesive sheet including an adhesive layer 2, and the adhesive layer 2 is an acrylic adhesive layer including an acrylic polymer as a base polymer. The acrylic polymer contains a structural unit derived from a monomer component (A) having a non-aromatic ring and having a glass transition temperature of 0 ℃ or higher, and the ratio of the structural unit derived from the monomer component (A) in the acrylic polymer is 5% by mass or higher. The storage modulus G 'of the adhesive layer 2 at-20 ℃ is 10MPa or more, and the storage modulus G' of the adhesive layer 2 at 65 ℃ is 0.05MPa or more.

Description

Double-sided adhesive sheet
Technical Field
The present invention relates to a double-sided adhesive sheet.
Background
In recent years, miniaturization of portable devices such as mobile phones, digital cameras, PDAs (portable information terminals) and the like has been advanced. Therefore, miniaturization and thickness reduction are also demanded for various electronic components to be mounted. For example, a mobile phone as a representative device of a portable device has a tendency that main components constituting the mobile phone are respectively thinned. In general, a display portion of a portable device mainly includes an LCD module and a backlight unit, and various sheet-like members are laminated in order to exhibit functions of light emission, reflection, light shielding, light guide, and the like. Therefore, a double-sided adhesive sheet (double-sided adhesive tape) for use in the assembly (joining) of these components is used.
For example, portable electronic devices are often at risk of falling due to the manner in which they are used. Therefore, the double-sided adhesive sheet used in the portable electronic device is required to have impact resistance such that it is not easily broken or peeled from the component by the impact of the portable electronic device falling off.
As a double-sided adhesive sheet used for a portable electronic device and having excellent impact resistance, for example, double-sided adhesive sheets disclosed in patent documents 1 to 3 are known.
Prior art literature
Patent literature
Patent document 1: japanese patent laid-open No. 2020-128453
Patent document 2: japanese patent laid-open No. 2020-128454
Patent document 3: japanese patent application laid-open No. 2021-24907
Disclosure of Invention
Problems to be solved by the invention
Since portable electronic devices are subjected to various impacts during non-operation, a double-sided adhesive sheet used in the portable electronic devices is required to have high shear adhesive strength in order to prevent peeling due to deformation of an adherend.
However, in general, when the pressure-sensitive adhesive layer is soft, the double-sided pressure-sensitive adhesive sheet tends to have excellent impact resistance, while the shear adhesion tends to be low. Therefore, it is difficult to realize a double-sided adhesive sheet excellent in impact resistance and having high shear adhesive force. Patent documents 1 to 3 do not mention that the impact resistance is excellent and the adhesive strength is high shear.
The present invention has been made in view of such circumstances, and an object thereof is to provide a double-sided adhesive sheet having excellent impact resistance and high shear adhesive strength.
Means for solving the problems
The present inventors have made intensive studies to achieve the above object, and as a result, have found that, in a double-sided adhesive sheet having no base material, a base polymer composition in an adhesive layer constituting the double-sided adhesive sheet has a specific composition and a storage modulus G' under 2 temperature conditions of the adhesive layer has a specific value, and that the double-sided adhesive sheet is excellent in impact resistance and has high shear adhesion. The present invention has been completed based on these findings.
That is, the present invention provides a double-sided adhesive sheet comprising an adhesive layer,
the adhesive layer is an acrylic adhesive layer comprising an acrylic polymer as a base polymer,
the acrylic polymer comprises structural units derived from a monomer component (A) having a homopolymer with a glass transition temperature of 0 ℃ or higher and a non-aromatic ring,
the proportion of the structural unit derived from the monomer component (A) in the acrylic polymer is 5% by mass or more,
The adhesive layer has a storage modulus G 'at-20 ℃ of 10MPa or more, and the adhesive layer has a storage modulus G' at 65 ℃ of 0.05MPa or more.
The acrylic polymer preferably contains a structural unit derived from an alkyl (meth) acrylate (B) having a linear or branched alkyl group having 2 to 7 carbon atoms.
The alkyl (meth) acrylate (B) preferably contains butyl (meth) acrylate, and the proportion of structural units derived from butyl (meth) acrylate in the acrylic polymer is preferably 50 mass% or more.
The adhesive layer is preferably an active energy ray-curable adhesive layer.
The acrylic polymer preferably contains a polyfunctional monomer copolymerizable with a monomer component forming the acrylic polymer as a constituent monomer component.
The non-aromatic ring is preferably an aliphatic hydrocarbon ring and/or a heterocyclic ring containing nitrogen atoms.
The glass transition temperature of the pressure-sensitive adhesive layer is preferably-10 ℃ or higher.
When the two-sided pressure-sensitive adhesive sheet is sandwiched between two stainless steel plates and the two pressure-sensitive adhesive surfaces are bonded to each other and the pressure-sensitive adhesive sheet is measured under conditions of a pulling speed of 10 mm/min and a peeling angle of 0 °, the shear adhesion force of the two-sided pressure-sensitive adhesive sheet to one stainless steel plate is preferably 1.0MPa or more.
The double-sided adhesive sheet is preferably used for fixing members of an electrical and electronic apparatus to each other.
In addition, the present invention provides an electric and electronic apparatus having the above-described double-sided adhesive sheet, the above-described double-sided adhesive sheet fixing members to each other through two adhesive surfaces.
Effects of the invention
The double-sided adhesive sheet of the present invention is excellent in impact resistance and has high shear adhesive strength. Therefore, for example, when used in a portable electronic device, the adherend is less likely to peel off even when subjected to a drop impact or deformation.
Drawings
Fig. 1 is a schematic cross-sectional view of a double-sided adhesive sheet according to an embodiment of the present invention.
Fig. 2 is an explanatory diagram schematically showing a method of measuring shear adhesion force.
Detailed Description
[ double-sided adhesive sheet ]
The double-sided adhesive sheet of the present invention is a double-sided adhesive sheet including an adhesive layer, and is a so-called "substrate-less" double-sided adhesive sheet having no substrate.
The pressure-sensitive adhesive layer is an acrylic pressure-sensitive adhesive layer containing an acrylic polymer as a base polymer, and has a storage modulus G 'at-20 ℃ of 10MPa or more and a storage modulus G' at 65 ℃ of 0.05MPa or more. The acrylic polymer contained in the acrylic pressure-sensitive adhesive layer contains a structural unit derived from a monomer component (sometimes referred to as "monomer component (a)") having a non-aromatic ring and having a glass transition temperature (Tg) of 0 ℃ or higher, and the proportion of the structural unit derived from the monomer component (a) in the acrylic polymer is 5 mass% or higher. In the present specification, the adhesive layer described above is sometimes referred to as "the adhesive layer of the present invention".
The pressure-sensitive adhesive layer constituting the double-sided pressure-sensitive adhesive sheet of the present invention may be a single layer or may be a plurality of layers. In the case where the double-sided adhesive sheet of the present invention is composed of a plurality of adhesive layers, the plurality of adhesive layers are all the adhesive layers of the present invention. The plurality of pressure-sensitive adhesive layers may be the same pressure-sensitive adhesive layer or may be pressure-sensitive adhesive layers having different compositions, thicknesses, physical properties, and the like.
Fig. 1 is a schematic cross-sectional view showing an embodiment of the double-sided adhesive sheet of the present invention. As shown in fig. 1, the double-sided adhesive sheet 1 is composed of a single layer of the adhesive layer 2 of the present invention. Release liners 3 and 4 are attached to the adhesive surface of the adhesive layer 2, respectively.
(adhesive layer of the invention)
The adhesive layer of the present invention is an acrylic adhesive layer containing an acrylic polymer as a base polymer exhibiting adhesion. In the present specification, the base polymer means a main component of polymer components in the adhesive constituting the adhesive layer, and for example, means a polymer component having a content of more than 50 mass%.
The proportion of the base polymer in the pressure-sensitive adhesive layer is preferably 60 mass% or more, more preferably 70 mass% or more, relative to 100 mass% of the total amount of the pressure-sensitive adhesive layer.
The acrylic polymer is a polymer containing an acrylic monomer (a monomer having a (meth) acryloyl group in a molecule) as a monomer component constituting the polymer. That is, the above acrylic polymer contains a structural unit derived from an acrylic monomer. The acrylic polymer may be used alone or in combination of two or more. The acrylic polymer may contain only one kind of acrylic monomer as a monomer component, or may contain two or more kinds of acrylic monomers as a monomer component. In the present specification, "(meth) acrylic acid" means "acrylic acid" and/or "methacrylic acid" ("acrylic acid" and "methacrylic acid" either or both), and the other is the same.
The acrylic polymer is a polymer formed (formed) from a monomer component (a) having a homopolymer with a glass transition temperature of 0 ℃ or higher and a non-aromatic ring as an essential monomer component. That is, the acrylic polymer contains the monomer component (a) as a structural unit. The acrylic polymer may contain only one monomer component (a) as a monomer component, or may contain two or more monomer components (a) as monomer components.
Examples of the non-aromatic ring include a non-aromatic hydrocarbon ring and a non-aromatic heterocyclic ring. The non-aromatic ring may be saturated or unsaturated. The non-aromatic hydrocarbon ring may be an aliphatic hydrocarbon ring, for example: cycloalkane rings such as cyclopentane ring, cyclohexane ring, cycloheptane ring, cyclooctane ring, etc.; cycloolefin rings such as cyclohexene ring; bridged hydrocarbon rings such as bicyclic hydrocarbon rings and tricyclic or higher aliphatic hydrocarbon rings. Examples of the bicyclic hydrocarbon ring include: pinane ring, pinene ring, pineapple ring, norbornane ring, norbornene ring, etc. Examples of the alicyclic hydrocarbon ring having three or more rings (bridged hydrocarbon ring having three or more rings) include a tetrahydrodicyclopentadiene ring, a dihydrodicyclopentadiene ring, an adamantane ring, a tetrahydrodicyclopentadiene ring, and a dihydrodicyclopentadiene ring.
Examples of the non-aromatic heterocyclic ring include: oxygen atom-containing heterocycles, nitrogen atom-containing heterocycles, sulfur atom-containing heterocycles, and the like. Examples of the oxygen atom-containing heterocyclic ring include: an oxolane ring, a furan ring, a pyran ring, a caprolactone ring, a caprolactam ring, a heterocyclic ring containing an oxygen atom and a nitrogen atom, and the like. Examples of the nitrogen atom-containing heterocycle include: an oxazolidine ring, an azacyclohexane ring, an azole ring, a piperidine ring, a caprolactam ring, a heterocyclic ring containing an oxygen atom and a nitrogen atom, a heterocyclic ring containing a nitrogen atom and a sulfur atom, and the like. Examples of the sulfur atom-containing heterocyclic ring include: thiacyclopentane ring, thiophene ring, heterocycle containing nitrogen atom and sulfur atom, and the like. Examples of the heterocyclic ring containing an oxygen atom and a nitrogen atom include a morpholine ring and the like. Examples of the heterocyclic ring containing a nitrogen atom and a sulfur atom include a thiazine ring and a thiazole ring.
The number of atoms constituting the non-aromatic ring is preferably 5 to 12, more preferably 6 to 10. The monomer component (a) is preferably a monomer component having an active energy ray polymerizable carbon-carbon double bond (for example, (meth) acryl, vinyl, etc.) and a non-aromatic ring, and examples thereof include a (meth) acrylate having a non-aromatic ring in an ester moiety, a monomer component having a vinyl group and a non-aromatic heterocyclic ring, and the like. In the (meth) acrylate, the non-aromatic ring is preferably bonded directly to a (meth) acryloyl group or bonded to a (meth) acryloyl group through an oxygen atom or an oxyalkylene group. Among these, aliphatic hydrocarbon rings and nitrogen atom-containing heterocyclic rings are preferable.
Specific examples of the monomer component (a) having an aliphatic hydrocarbon ring as the non-aromatic ring include: cycloalkyl (meth) acrylates such as cyclopentyl (meth) acrylate, cyclohexyl (meth) acrylate, cycloheptyl (meth) acrylate, and cyclooctyl (meth) acrylate; (meth) acrylic esters having a bicyclic aliphatic hydrocarbon ring such as isobornyl (meth) acrylate; and (meth) acrylic esters having an aliphatic hydrocarbon ring having three or more rings, such as tetrahydrodicyclopentadienyl (meth) acrylate, tetrahydrodicyclopentadienyloxyethyl (meth) acrylate, dihydrodicyclopentadienyloxyethyl (meth) acrylate, tetrahydrotricyclopentadienyl (meth) acrylate, 1-adamantyl (meth) acrylate, 2-methyl-2-adamantyl (meth) acrylate, and 2-ethyl-2-adamantyl (meth) acrylate.
Specific examples of the monomer component (a) in which the non-aromatic ring is a nitrogen atom-containing heterocyclic ring include: n- (meth) acryloylmorpholine, N-vinyl-2-pyrrolidone, N-vinyl-2-piperidone, N-vinyl-3-morpholine, N-vinyl-2-caprolactam, N-vinyl-1, 3-Oxazin-2-one, N-vinyl-3, 5-morpholindione, N-vinylpiperazine, N-vinylpyrazine, N-vinylmorpholine, N-vinylpyrazole, vinylpyridine, 2-vinyl-2->Oxazoline, 2-vinyl-5-methyl-2->Oxazoline, 2-isopropenyl-2->Oxazolines, vinylpyridines, (meth) acryloylpyrrolidines, N- (meth) acryloylpiperidines, and the like.
The Tg of the homopolymer of the monomer component (A) is 0℃or higher, preferably 10℃or higher, and more preferably 60℃or higher. When the Tg is 0℃or higher, the storage modulus G' becomes high and the impact resistance is excellent. The Tg is, for example, 200℃or lower.
In the present specification, "glass transition temperature (Tg) at the time of forming a homopolymer (sometimes simply referred to as" Tg of homopolymer ") means" glass transition temperature (Tg) of single polymer of the monomer ", and specifically, values in" handbook of polymers "(3 rd edition, john wiley & Sons, inc, 1987) are cited. The Tg of the homopolymer of the monomer not described in the above-mentioned document refers to, for example, a value obtained by the following measurement method (refer to japanese patent application laid-open No. 2007-51271). That is, 100 parts by mass of a monomer, 0.2 parts by mass of 2,2' -azobisisobutyronitrile and 200 parts by mass of ethyl acetate as a polymerization solvent were charged into a reactor having a thermometer, a stirrer, a nitrogen introduction pipe and a reflux condenser, and stirred for 1 hour while introducing nitrogen. The oxygen in the polymer system was removed in this manner, and the temperature was raised to 63℃and the reaction was carried out for 10 hours. Then, the mixture was cooled to room temperature to obtain a homopolymer solution having a solid content concentration of 33% by mass. Subsequently, the homopolymer solution was cast on a release liner and dried, thereby producing a test sample (sheet-like homopolymer) having a thickness of about 2 mm. Then, the test specimen was punched out into a disk shape having a diameter of 7.9mm and sandwiched between parallel plates, and the viscoelasticity was measured by a viscoelasticity tester (trade name "ARES", manufactured by Rheometrics Co.) at a temperature range of-70 to 150℃and a temperature rise rate of 5℃per minute while applying a shear strain having a frequency of 1Hz, and the peak top temperature of tan. Delta. Was defined as Tg of the homopolymer by a shear mode.
The proportion of the monomer component (a) is 5 mass% or more, preferably 10 mass% or more, and more preferably 15 mass% or more, based on 100 mass% of the total amount of all the monomer components constituting the acrylic polymer. When the ratio is 5% by mass or more, the storage modulus G '(in particular, the storage modulus G' at-20 ℃) becomes high, and the impact resistance is excellent. The proportion of the monomer component (a) is preferably 60 mass% or less, more preferably 50 mass% or less, and still more preferably 40 mass% or less. When the ratio is 60% by mass or less, flexibility is improved, and adhesiveness to an adherend and shear adhesion strength can be improved.
The acrylic polymer is preferably a polymer formed by (forming) an alkyl (meth) acrylate (sometimes referred to as an alkyl (meth) acrylate (B) ") as a monomer component together with the monomer component (a).
The alkyl (meth) acrylate (B) is preferably an alkyl (meth) acrylate having a linear alkyl group or a branched alkyl group. The alkyl (meth) acrylate (B) may be used alone or in combination of two or more.
The alkyl (meth) acrylate having a linear alkyl group or a branched alkyl group is not particularly limited, and examples thereof include: methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, isopropyl (meth) acrylate, n-butyl (meth) acrylate, isobutyl (meth) acrylate, sec-butyl (meth) acrylate, t-butyl (meth) acrylate, pentyl (meth) acrylate, isopentyl (meth) acrylate, hexyl (meth) acrylate, heptyl (meth) acrylate, octyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, isooctyl (meth) acrylate, nonyl (meth) acrylate, isononyl (meth) acrylate, decyl (meth) acrylate, isodecyl (meth) acrylate, undecyl (meth) acrylate, dodecyl (meth) acrylate, lauryl (meth) acrylate, tridecyl (meth) acrylate, tetradecyl (meth) acrylate, pentadecyl (meth) acrylate, hexadecyl (meth) acrylate, heptadecyl (meth) acrylate, octadecyl (meth) acrylate, stearyl (meth) acrylate, isostearyl (meth) acrylate, nonadecyl (meth) acrylate, and mixtures thereof, alkyl (meth) acrylates having a linear or branched alkyl group having 1 to 20 carbon atoms, such as eicosyl (meth) acrylate. Among them, the alkyl (meth) acrylate having a linear or branched alkyl group is preferably an alkyl (meth) acrylate having a linear or branched alkyl group having 2 to 7 carbon atoms, more preferably butyl (meth) acrylate, from the viewpoint of selecting a lower storage modulus G'. In addition, methyl (meth) acrylate may be contained.
The proportion of the alkyl (meth) acrylate (B) in 100 mass% of the total amount of all the monomer components constituting the acrylic polymer is not particularly limited, but is preferably 50 mass% or more, more preferably 60 mass% or more, and still more preferably 65 mass% or more. When the above ratio is 50 mass% or more, the balance with the amount of the monomer component (a) is good, and an adhesive layer having good adhesion even if thin can be formed. The proportion is preferably 94% by mass or less, more preferably 90% by mass or less, and still more preferably 85% by mass or less. The ratio of butyl (meth) acrylate is preferably within the above range.
The acrylic polymer may contain a copolymerizable monomer together with the monomer component (a) and the alkyl (meth) acrylate (B) as monomer components constituting the polymer. That is, the acrylic polymer may contain a copolymerizable monomer as a structural unit. The copolymerizable monomer may be used alone or in combination of two or more.
The copolymerizable monomer is preferably a carboxyl group-containing monomer and/or an acid anhydride monomer, from the viewpoints of being capable of forming an adhesive layer having good adhesion even when thin, improving the cohesive force, and further improving the impact resistance. Examples of the carboxyl group-containing monomer include: acrylic acid, methacrylic acid, carboxyethyl (meth) acrylate, carboxypentyl (meth) acrylate, itaconic acid, maleic acid, fumaric acid, crotonic acid, and the like. Examples of the acid anhydride monomer include maleic anhydride and itaconic anhydride.
The proportion of the carboxyl group-containing monomer and/or the acid anhydride monomer in 100 mass% of the total amount of all the monomer components constituting the acrylic polymer is not particularly limited, but is preferably 0.2 mass% or more, more preferably 1 mass% or more, and still more preferably 5 mass% or more. The proportion is preferably 20% by mass or less, more preferably 15% by mass or less, and still more preferably 10% by mass or less. When the ratio is within the above range, the balance with the amounts of the monomer component (a) and the alkyl (meth) acrylate (B) is good, and an adhesive layer excellent in impact resistance and having good adhesion even if thin can be formed.
As the copolymerizable monomer, a functional group-containing monomer may be further contained for the purpose of introducing a crosslinking point into the acrylic polymer or improving the cohesive force of the acrylic polymer. Examples of the functional group-containing monomer include: hydroxyl group-containing monomers, nitrogen atom-containing monomers (excluding monomers belonging to the monomer component (A)), ketone group-containing monomers, alkoxysilyl group-containing monomers, sulfonic acid group-containing monomers, phosphoric acid group-containing monomers, and the like. The functional group-containing monomer may be used alone or in combination of two or more.
Examples of the hydroxyl group-containing monomer include: hydroxyalkyl (meth) acrylates such as 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 3-hydroxypropyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, 6-hydroxyhexyl (meth) acrylate, 8-hydroxyoctyl (meth) acrylate, 10-hydroxydecyl (meth) acrylate, 12-hydroxylauryl (meth) acrylate, and (4-hydroxymethylcyclohexyl) methyl (meth) acrylate; unsaturated alcohols such as vinyl alcohol and allyl alcohol; polypropylene glycol mono (meth) acrylate, and the like.
Examples of the nitrogen atom-containing monomer include: amide group-containing monomers, amino group-containing monomers, cyano group-containing monomers, and the like. Examples of the amide group-containing monomer include: (meth) acrylamide, N-dimethyl (meth) acrylamide, N-butyl (meth) acrylamide, N-hydroxymethyl propane (meth) acrylamide, N-methoxymethyl (meth) acrylamide, N-butoxymethyl (meth) acrylamide, and the like. Examples of the amino group-containing monomer include: aminoethyl (meth) acrylate, N-dimethylaminoethyl (meth) acrylate, t-butylaminoethyl (meth) acrylate, and the like. Examples of the cyano group-containing monomer include: acrylonitrile, methacrylonitrile.
Examples of the ketone group-containing monomer include: diacetone (meth) acrylamide, diacetone (meth) acrylate, vinyl methyl ketone, vinyl ethyl ketone, allyl acetoacetate, vinyl acetoacetate, and the like.
Examples of the alkoxysilyl group-containing monomer include: 3- (meth) acryloxypropyl trimethoxysilane, 3- (meth) acryloxypropyl triethoxysilane, 3- (meth) acryloxypropyl methyldimethoxysilane, 3- (meth) acryloxypropyl methyldiethoxysilane, and the like.
Examples of the sulfonic acid group-containing monomer include: styrene sulfonic acid, allyl sulfonic acid, 2- (meth) acrylamide-2-methylpropane sulfonic acid, (meth) acrylamide propane sulfonic acid, sulfopropyl (meth) acrylate, and (meth) acryloxynaphthalene sulfonic acid.
Examples of the phosphate group-containing monomer include: 2-hydroxyethyl acryloyl phosphate, and the like.
The proportion of the functional group-containing monomer may be, for example, 0.1 mass% or more, 0.5 mass% or more, 1 mass% or more, 5 mass% or more, or 10 mass% or more, based on 100 mass% of the total amount of all monomer components constituting the acrylic polymer. The proportion may be, for example, 40 mass% or less and 20 mass% or less, and may be substantially not contained. In the present specification, substantially not means that the mixture is not actively mixed and is not intentionally mixed, and the mixture is, for example, 0.05 mass% or less and 0.01 mass% or less.
Other monomers may also be included as the copolymerizable monomer described above. Examples of the other monomer include: vinyl ester monomers such as vinyl acetate, vinyl propionate and vinyl laurate; aromatic vinyl compounds such as styrene, substituted styrene (α -methylstyrene, etc.), and vinyl toluene; olefin monomers such as ethylene, propylene, isoprene, butadiene, and isobutylene; chlorine-containing monomers such as vinyl chloride and vinylidene chloride; isocyanate group-containing monomers such as 2- (meth) acryloyloxyethyl isocyanate; an alkoxy group-containing monomer such as methoxyethyl (meth) acrylate and ethoxyethyl (meth) acrylate; vinyl ether monomers such as methyl vinyl ether and ethyl vinyl ether; aryl (meth) acrylates such as phenyl (meth) acrylate, aryloxyalkyl (meth) acrylate such as phenoxyethyl (meth) acrylate, arylalkyl (meth) acrylate such as benzyl (meth) acrylate, and (meth) acrylates having an aromatic ring.
The proportion of the other monomer may be, for example, 0.05 mass% or more and 0.5 mass% or more, based on 100 mass% of the total amount of all the monomer components constituting the acrylic polymer. The proportion may be, for example, 20 mass% or less, 10 mass% or less, or 5 mass% or less, or may be substantially not contained.
In order to form a crosslinked structure in the polymer skeleton of the acrylic polymer, the acrylic polymer may contain a polyfunctional monomer copolymerizable with the monomer component forming the acrylic polymer as a monomer component constituting the polymer. Examples of the polyfunctional monomer include: multifunctional (meth) acrylates such as hexanediol di (meth) acrylate, (poly) ethylene glycol di (meth) acrylate, (poly) propylene glycol di (meth) acrylate, neopentyl glycol di (meth) acrylate, pentaerythritol di (meth) acrylate, trimethylolpropane tri (meth) acrylate, pentaerythritol tri (meth) acrylate, dipentaerythritol hexa (meth) acrylate, and the like; epoxy (meth) acrylates (e.g., polyglycidyl (meth) acrylate), polyester (meth) acrylates, urethane (meth) acrylates, and the like, monomers having a (meth) acryloyl group and other reactive functional groups in the molecule, and the like. The polyfunctional monomer may be used alone or in combination of two or more.
The proportion of the polyfunctional monomer is preferably 0.05 mass% or more, more preferably 0.07 mass%, and even more preferably 0.10 mass% or more, based on 100 mass% of the total amount of all monomer components constituting the acrylic polymer. The proportion may be 5% by mass or less and 3% by mass or less, and may be substantially absent.
The acrylic polymer preferably has a structural part derived from a photopolymerization initiator. The acrylic polymer having a structural portion derived from a photopolymerization initiator means that the acrylic polymer and the adhesive layer of the present invention are a polymer polymerized by irradiation of active energy rays or a cured adhesive layer. The photopolymerization initiator may be a photopolymerization initiator described below.
The acrylic polymer is preferably a polymerization reaction product obtained by polymerizing a composition containing one or more selected from the group consisting of an acrylic partial polymer, an acrylic oligomer, and a monomer component. In the case where the acrylic polymer is a polymerization reaction product obtained by polymerizing a composition containing only a monomer component, the monomer component contains at least an acrylic monomer. Among these, polymerization reaction products of compositions comprising acrylic part polymers are preferred. The "partial polymer" is sometimes referred to as "prepolymer", "slurry", etc. The acrylic partial polymer, acrylic oligomer and monomer component may each be used alone or in combination of two or more. The monomer component that may be contained in the composition is sometimes referred to as "monomer component (C)".
The acrylic partial polymer and the acrylic oligomer are both compounds each composed of an acrylic monomer as an indispensable monomer component. The monomer components and the monomer component (C) constituting the acrylic partial polymer and the acrylic oligomer may be exemplified by the monomer components exemplified and described as the monomer components constituting the acrylic polymer.
The acrylic partial polymer may be obtained by polymerizing a monomer component at a polymerization conversion rate of, for example, 95 mass% or less, unlike the full polymer. The polymerization conversion is preferably 70 mass% or less, more preferably 60 mass% or less, further preferably 50 mass% or less, further preferably 40 mass% or less, particularly preferably 35 mass% or less. The polymerization conversion is preferably 1 mass% or more, more preferably 5 mass% or more.
The acrylic partial polymer contains an acrylic monomer as a structural unit. The acrylic partial polymer preferably contains a monomer component (a) as a structural unit. The monomer component contained in the structural unit may be one or two or more.
The proportion of the monomer component (a) is preferably 5 mass% or more, more preferably 10 mass% or more, and still more preferably 15 mass% or more, based on 100 mass% of the total amount of all the monomer components constituting the acrylic partial polymer. When the ratio is 5% by mass or more, the storage modulus G '(in particular, the storage modulus G' at-20 ℃) becomes high, and the impact resistance is more excellent. The proportion of the monomer component (a) is preferably 60 mass% or less, more preferably 50 mass% or less, and still more preferably 40 mass% or less. When the ratio is 60% by mass or less, flexibility is improved, and adhesion to an adherend and shear adhesion strength can be further improved.
The acrylic partial polymer preferably contains an alkyl (meth) acrylate (B) as a structural unit. The alkyl (meth) acrylate (B) is preferably an alkyl (meth) acrylate having a linear or branched alkyl group having 2 to 7 carbon atoms, and more preferably butyl (meth) acrylate. The alkyl (meth) acrylate (B) contained as the structural unit may be one kind or two or more kinds.
The proportion of the alkyl (meth) acrylate (B) is preferably 50% by mass or more, more preferably 60% by mass or more, and still more preferably 65% by mass or more, based on 100% by mass of the total amount of all the monomer components constituting the acrylic partial polymer. The proportion is preferably 94% by mass or less, more preferably 90% by mass or less, and still more preferably 85% by mass or less.
The acrylic partial polymer may contain the copolymerizable monomer as a structural unit. Among these copolymerizable monomers, monomers containing a carboxyl group and/or acid anhydride monomers are preferable from the viewpoint of being able to form an adhesive layer having good adhesion even if it is thin.
The proportion of the carboxyl group-containing monomer and/or the acid anhydride monomer is not particularly limited, but is preferably 0.2 mass% or more, more preferably 1 mass% or more, and still more preferably 5 mass% or more, based on 100 mass% of the total amount of all the monomer components constituting the acrylic partial polymer. The proportion is preferably 20% by mass or less, more preferably 15% by mass or less, and still more preferably 11% by mass or less.
The acrylic polymer may be the polymerization reaction product of a composition comprising an acrylic partial polymer and an acrylic oligomer. In this case, the storage modulus G' at-20℃is further increased.
The weight average molecular weight of the acrylic oligomer is preferably 2500 to 10000, more preferably 3000 to 8000. The weight average molecular weight can be obtained by GPC and converted to polystyrene. For example, the measurement can be performed under the following conditions using a high-speed GPC apparatus "HPLC-8120gPC" manufactured by Tosoh Corp.
Column: TSKgel SuperHZM-H/HZ4000/HZ3000/HZ2000
Solvent: tetrahydrofuran (THF)
Flow rate: 0.6 ml/min
The above acrylic oligomer contains an acrylic monomer as a structural unit. The acrylic oligomer preferably contains a monomer component (a) as a structural unit. The monomer component contained as the structural unit may be one or two or more.
The proportion of the monomer component (a) is preferably 40 mass% or more, more preferably 50 mass% or more, and still more preferably 55 mass% or more, based on 100 mass% of the total amount of all the monomer components constituting the acrylic oligomer. The proportion is preferably 90% by mass or less, more preferably 80% by mass or less.
The above acrylic oligomer preferably contains an alkyl (meth) acrylate (B) as a structural unit. As the alkyl (meth) acrylate (B), methyl Methacrylate (MMA) is preferable. The proportion of the alkyl (meth) acrylate (B) in the entire monomer components constituting the acrylic oligomer is preferably 10% by mass or more, more preferably 20% by mass or more. The proportion is preferably 60% by mass or less, more preferably 50% by mass or less, and still more preferably 45% by mass or less. The acrylic oligomer preferably contains the copolymerizable monomer as a structural unit.
The content of the acrylic oligomer is preferably 0.5 to 35 parts by mass, more preferably 2 to 20 parts by mass, and even more preferably 4 to 10 parts by mass, based on 100 parts by mass of the total amount of the acrylic partial polymer. When the content is within the above range, the storage modulus G' at-20℃tends to be high.
The acrylic polymer may be a polymerization reaction product of a composition comprising an acrylic partial polymer and a monomer component (C). In this case, the storage modulus G' is further increased, and the shear adhesion becomes high.
The monomer component (C) may be a monomer component exemplified and described as a monomer component which may be contained in the acrylic polymer as a structural unit. The monomer component (C) preferably contains the monomer component (A). The proportion of the monomer component (a) in the monomer component (C) is preferably 60 to 95% by mass, more preferably 70 to 90% by mass.
The monomer component (C) may contain the copolymerizable monomer described above. Among these copolymerizable monomers, monomers containing a carboxyl group and/or acid anhydride monomers are preferable from the viewpoint of being able to form an adhesive layer having good adhesion even if it is thin. The proportion of the carboxyl group-containing monomer and/or the acid anhydride monomer in the monomer component (C) is not particularly limited, but is preferably 5 to 40% by mass, more preferably 10 to 30% by mass.
The content of the monomer component (C) is preferably 1 to 30 parts by mass, more preferably 10 to 20 parts by mass, relative to 100 parts by mass of the total amount of the acrylic partial polymer. When the content is within the above range, the storage modulus G' is further increased, and the shear adhesion becomes high.
The acrylic partial polymer and the acrylic oligomer are obtained by polymerizing monomer components. The acrylic polymer is obtained by polymerizing a composition containing at least one selected from the group consisting of the acrylic partial polymer, the acrylic oligomer, and the monomer component (C). The polymerization method is not particularly limited, and examples thereof include: a solution polymerization method, an emulsion polymerization method, a bulk polymerization method, a thermal polymerization method, a polymerization method using irradiation of active energy rays (active energy ray polymerization method), and the like. Among them, the bulk polymerization method, the thermal polymerization method, and the active energy ray polymerization method are preferable from the viewpoint of enabling the crosslinking to be dense.
In addition, various general solvents can be used in the polymerization of the above monomer components and the like. Examples of the solvent include: esters such as ethyl acetate and n-butyl acetate; aromatic hydrocarbons such as toluene and benzene; aliphatic hydrocarbons such as n-hexane and n-heptane; alicyclic hydrocarbons such as cyclohexane and methylcyclohexane; organic solvents such as ketones including methyl ethyl ketone and methyl isobutyl ketone. The solvent may be used alone or in combination of two or more.
In the polymerization of the monomer component, a polymerization initiator such as a thermal polymerization initiator and a photopolymerization initiator (photoinitiator) may be used depending on the kind of polymerization reaction. The polymerization initiator may be used alone or in combination of two or more.
The thermal polymerization initiator is not particularly limited, and examples thereof include: azo-based polymerization initiators, peroxide-based polymerization initiators (e.g., persulfates such as dibenzoyl peroxide, t-butyl peroxymaleate, and potassium persulfate), phenyl-substituted ethane-based initiators such as benzoyl peroxide, and hydrogen peroxide, aromatic carbonyl compounds, and redox-type polymerization initiators. Among them, the azo-based polymerization initiator disclosed in Japanese patent application laid-open No. 2002-69411 is preferable. The azo-based polymerization initiator may be: 2,2 '-azobisisobutyronitrile, 2' -azobis (2-methylbutyronitrile), dimethyl 2,2 '-azobis (2-methylpropionate), 4' -azobis (4-cyanovaleric acid), and the like. The amount of the thermal polymerization initiator to be used may be a usual amount, and for example, the amount of the thermal polymerization initiator to be used may be selected from the range of, for example, 0.005 to 1 part by mass, preferably 0.01 to 1 part by mass, based on 100 parts by mass of the monomer component.
The photopolymerization initiator is not particularly limited, and examples thereof include: benzoin ether photopolymerization initiator and benzeneAn ethanone photopolymerization initiator, an α -ketol photopolymerization initiator, an aromatic sulfonyl chloride photopolymerization initiator, a photoactive oxime photopolymerization initiator, a benzoin photopolymerization initiator, a benzil photopolymerization initiator, a benzophenone photopolymerization initiator, a ketal photopolymerization initiator, a thioxanthone photopolymerization initiator, and the like. Also, an acylphosphine oxide-based photopolymerization initiator and a titanocene-based photopolymerization initiator can be mentioned. Examples of the benzoin ether photopolymerization initiator include: benzoin methyl ether, benzoin ethyl ether, benzoin propyl ether, benzoin isopropyl ether, benzoin isobutyl ether, 2-dimethoxy-1, 2-diphenylethane-1-one, anisoin methyl ether, and the like. Examples of the acetophenone photopolymerization initiator include: 2, 2-diethoxyacetophenone, 2-dimethoxy-2-phenylacetophenone, 1-hydroxycyclohexylphenyl ketone, 4-phenoxydichloroacetophenone, 4- (tert-butyl) dichloroacetophenone, and the like. Examples of the α -ketol photopolymerization initiator include: 2-methyl-2-hydroxy-propiophenone and 1- [4- (2-hydroxyethyl) phenyl group ]-2-methylpropan-1-one and the like. Examples of the aromatic sulfonyl chloride photopolymerization initiator include 2-naphthalenesulfonyl chloride. Examples of the photoactive oxime-type photopolymerization initiator include: 1-phenyl-1, 1-propanedione-2- (O-ethoxycarbonyl) oxime and the like. Examples of the benzoin photopolymerization initiator include benzoin. Examples of the benzil photopolymerization initiator include benzil. Examples of the benzophenone photopolymerization initiator include: benzophenone, benzoyl benzoic acid, 3' -dimethyl-4-methoxybenzophenone, polyvinylbenzophenone, α -hydroxycyclohexyl phenyl ketone, and the like. Examples of the ketal photopolymerization initiator include benzildimethyl ketal. Examples of the thioxanthone photopolymerization initiator include: thioxanthone, 2-chlorothioxanthone, 2-methylthioxanthone, 2, 4-dimethylthioxanthone, isopropylthioxanthone, 2, 4-diisopropylthioxanthone, dodecylthioxanthone, and the like. Examples of the acylphosphine oxide photopolymerization initiator include: 2,4, 6-trimethylbenzoyl diphenyl phosphine oxide, bis (2, 4, 6-trimethylbenzoyl) phenyl Phosphine oxides, and the like. Examples of the titanocene-based photopolymerization initiator include: bis (eta) 5 -2, 4-cyclopentadien-1-yl) -bis (2, 6-difluoro-3- (1H-pyrrol-1-yl) -phenyl) -titanium and the like. The amount of the photopolymerization initiator to be used may be any amount as long as it is a usual amount, and may be selected from, for example, 0.01 to 3 parts by mass, preferably 0.1 to 1.5 parts by mass, based on 100 parts by mass of the monomer component.
The adhesive layer of the present invention preferably further contains a filler. By compounding the filler, the storage modulus G' at-20℃and 65℃is easily adjusted. The filler may be used alone or in combination of two or more.
The shape of the filler is not particularly limited, and a granular or fibrous filler may be used. Among them, the granule form is preferable. The filler may be any of organic and inorganic substances.
Examples of the material constituting the inorganic substance include: metals such as copper, silver, gold, platinum, nickel, aluminum, chromium, iron, stainless steel, and the like; metal oxides such as aluminum oxide, silicon oxide (silica), titanium oxide, zirconium oxide, zinc oxide, tin oxide, copper oxide, and nickel oxide; metal hydroxides and hydrated metal compounds such as aluminum hydroxide, boehmite, magnesium hydroxide, calcium hydroxide, zinc hydroxide, silicic acid, iron hydroxide, copper hydroxide, barium hydroxide, zirconium oxide hydrate, tin oxide hydrate, basic magnesium carbonate, hydrotalcite, dawsonite, borax, and zinc borate; carbides such as silicon carbide, boron carbide, nitrogen carbide, and calcium carbide; nitrides such as aluminum nitride, silicon nitride, boron nitride, and gallium nitride; carbonates such as calcium carbonate; titanates such as barium titanate and potassium titanate; carbon substances such as carbon black, carbon tubes (carbon nanotubes), carbon fibers, and diamond; inorganic materials such as glass; and natural raw material particles such as volcanic sand, clay, sand and the like.
Examples of the material constituting the organic substance include: polystyrene, acrylic resins (e.g., polymethyl methacrylate), phenolic resins, phenylguanamine resins, urea-formaldehyde resins, silicone resins, polyesters, polyurethanes, polyethylene, polypropylene, polyamides (e.g., nylon, etc.), polyimide, polyvinylidene chloride, etc., polymers, and the like.
The above-mentioned filler may have a hollow body structure. The hollow portion (the inner space of the hollow particle) of the filler having the hollow body structure may be in a vacuum state or may be filled with a medium. Examples of the medium include inert gases such as nitrogen and argon, air, and volatile solvents.
Among these fillers, fillers whose surface is composed of an organic or inorganic substance other than an acrylic resin and fillers having a hollow structure are preferable. These fillers have a small interaction with the acrylic component in the acrylic pressure-sensitive adhesive layer or have a hollow structure, and therefore are not likely to break when the pressure-sensitive adhesive layer is stretched, and are excellent in peelability (reworkability) when peeled off after the double-sided pressure-sensitive adhesive sheet is adhered to an adherend.
The average particle diameter of the particulate filler is, for example, 0.5 to 80. Mu.m, preferably 1 to 40. Mu.m. When the average particle diameter is within the above range, the hardness of the adhesive layer can be made moderate. The average particle diameter is a median particle diameter (D50) measured by a dynamic light scattering method.
The proportion of the filler in the adhesive layer of the present invention is preferably 0.5 to 10 mass%, more preferably 1 to 5 mass%, relative to 100 mass% of the total amount of the adhesive layer. When the ratio is within the above range, the hardness of the adhesive layer can be made moderate. In addition, reworkability is excellent.
The adhesive layer of the present invention may contain a colorant. The pressure-sensitive adhesive layer is colored by containing a colorant, and the double-sided pressure-sensitive adhesive sheet of the present invention is excellent in visibility and design. The colorant may be a pigment or a dye. Examples of the coloring agent include: black-based colorants, cyan-based colorants, magenta-based colorants, yellow-based colorants, and the like. From the viewpoint of more excellent visibility and design, a black colorant is preferable. The colorant may be contained in one kind or two or more kinds. The proportion of the colorant in the pressure-sensitive adhesive layer of the present invention is preferably 0.05 to 5% by mass, more preferably 0.1 to 2% by mass, relative to 100% by mass of the total amount of the pressure-sensitive adhesive layer.
Examples of the black colorant include: carbon black, carbon nanotubes, graphite (black lead), copper oxide, manganese dioxide, azoic pigments such as azomethine azo black, aniline black, perylene black, titanium black, cyanine black, activated carbon, ferrite, magnetite, chromium oxide, iron oxide, molybdenum disulfide, composite oxide black pigments, anthraquinone organic black dyes, azo organic black dyes, and the like. Examples of the carbon black include: furnace black, channel black, acetylene black, thermal black, lamp black, and the like. As the black-based colorant, there may be mentioned: c.i. solvent black 3, c.i. solvent black 7, c.i. solvent black 22, c.i. solvent black 27, c.i. solvent black 29, c.i. solvent black 34, c.i. solvent black 43, c.i. solvent black 70; c.i. direct black 17, c.i. direct black 19, c.i. direct black 22, c.i. direct black 32, c.i. direct black 38, c.i. direct black 51, c.i. direct black 71; c.i. acid black 1, c.i. acid black 2, c.i. acid black 24, c.i. acid black 26, c.i. acid black 31, c.i. acid black 48, c.i. acid black 52, c.i. acid black 107, c.i. acid black 109, c.i. acid black 110, c.i. acid black 119, c.i. acid black 154; c.i. disperse black 1, c.i. disperse black 3, c.i. disperse black 10, c.i. disperse black 24; c.i. pigment black 1, c.i. pigment black 7, etc.
Examples of the cyan colorant include: c.i. solvent blue 25, c.i. solvent blue 36, c.i. solvent blue 60, c.i. solvent blue 70, c.i. solvent blue 93, c.i. solvent blue 95; c.i. acid blue 6, c.i. acid blue 45; c.i. pigment blue 1, c.i. pigment blue 2, c.i. pigment blue 3, c.i. pigment blue 15: 1. c.i. pigment blue 15: 2. c.i. pigment blue 15: 3. c.i. pigment blue 15: 4. c.i. pigment blue 15: 5. c.i. pigment blue 15: 6. c.i. pigment blue 16, c.i. pigment blue 17: 1. c.i. pigment blue 18, c.i. pigment blue 22, c.i. pigment blue 25, c.i. pigment blue 56, c.i. pigment blue 60, c.i. pigment blue 63, c.i. pigment blue 65, c.i. pigment blue 66; c.i. vat blue 4; c.i. vat blue 60, c.i. pigment green 7, etc. Cyan color
Examples of the magenta-based coloring agent include: c.i. solvent red 1, c.i. solvent red 3, c.i. solvent red 8, c.i. solvent red 23, c.i. solvent red 24, c.i. solvent red 25, c.i. solvent red 27, c.i. solvent red 30, c.i. solvent red 49, c.i. solvent red 52, c.i. solvent red 58, c.i. solvent red 63, c.i. solvent red 81, c.i. solvent red 82, c.i. solvent red 83, c.i. solvent red 84, c.i. solvent red 100, c.i. solvent red 109, c.i. solvent red 111, c.i. solvent red 121, c.i. solvent red 122; c.i. disperse red 9; c.i. solvent violet 8, c.i. solvent violet 13, c.i. solvent violet 14, c.i. solvent violet 21, c.i. solvent violet 27; c.i. disperse violet 1; c.i. basic red 1, c.i. basic red 2, c.i. basic red 9, c.i. basic red 12, c.i. basic red 13, c.i. basic red 14, c.i. basic red 15, c.i. basic red 17, c.i. basic red 18, c.i. basic red 22, c.i. basic red 23, c.i. basic red 24, c.i. basic red 27, c.i. basic red 29, c.i. basic red 32, c.i. basic red 34, c.i. basic red 35, c.i. basic red 36, c.i. basic red 37, c.i. basic red 38, c.i. basic red 39, c.i. basic red 40; c.i. basic violet 1, c.i. basic violet 3, c.i. basic violet 7, c.i. basic violet 10, c.i. basic violet 14, c.i. basic violet 15, c.i. basic violet 21, c.i. basic violet 25, c.i. basic violet 26, c.i. basic violet 27, c.i. basic violet 28, etc. Examples of the magenta-based coloring agent include: c.i. pigment red 1, c.i. pigment red 2, c.i. pigment red 3, c.i. pigment red 4, c.i. pigment red 5, c.i. pigment red 6, c.i. pigment red 7, c.i. pigment red 8, c.i. pigment red 9, c.i. pigment red 10, c.i. pigment red 11, c.i. pigment red 12, c.i. pigment red 13, c.i. pigment red 14, c.i. pigment red 15, c.i. pigment red 16, c.i. pigment red 17, c.i. pigment red 18, c.i. pigment red 19, c.i. pigment red 21, c.i. pigment red 22, c.i. pigment red 23, c.i. pigment red 30, c.i. pigment red 31, c.i. pigment red 32, c.i. pigment red 37, c.i. pigment red 38, c.i. pigment red 39, c.i. pigment red 40, c.i. pigment red 41, c.i. pigment red 48, c.i. pigment red 42. 1. C.i. pigment red 48: 2. c.i. pigment red 48: 3. c.i. pigment red 48: 4. c.i. pigment red 49, c.i. pigment red 49: 1. c.i. pigment red 50, c.i. pigment red 51, c.i. pigment red 52: 2. c.i. pigment red 53: 1. c.i. pigment red 54, c.i. pigment red 55, c.i. pigment red 56, c.i. pigment red 57: 1. c.i. pigment red 58, c.i. pigment red 60: 1. c.i. pigment red 63, c.i. pigment red 63: 1. c.i. pigment red 63: 2. c.i. pigment red 64, c.i. pigment red 64: 1. c.i. pigment red 67, c.i. pigment red 68, c.i. pigment red 81, c.i. pigment red 83, c.i. pigment red 87, c.i. pigment red 88, c.i. pigment red 89, c.i. pigment red 90, c.i. pigment red 92, c.i. pigment red 101, c.i. pigment red 104, c.i. pigment red 105, c.i. pigment red 106, c.i. pigment red 108, c.i. pigment red 112, c.i. pigment red 114, c.i. pigment red 122, c.i. pigment red 123, c.i. pigment red 139, c.i. pigment red 144, c.i. pigment red 146, c.i. pigment red 147, c.i. pigment red 149, c.i. pigment red 150, c.i. pigment red 151, c.i. pigment red c.i. pigment red 163, c.i. pigment red 166, c.i. pigment red 168, c.i. pigment red 170, c.i. pigment red 171, c.i. pigment red 172, c.i. pigment red 175, c.i. pigment red 176, c.i. pigment red 177, c.i. pigment red 178, c.i. pigment red 179, c.i. pigment red 184, c.i. pigment red 185, c.i. pigment red 187, c.i. pigment red 190, c.i. pigment red 193, c.i. pigment red 202, c.i. pigment red 206, c.i. pigment red 207, c.i. pigment red 209, c.i. pigment red 219, c.i. pigment red 222, c.i. pigment red 224, c.i. pigment red 238, c.i. pigment red 245; c.i. pigment violet 3, c.i. pigment violet 9, c.i. pigment violet 19, c.i. pigment violet 23, c.i. pigment violet 31, c.i. pigment violet 32, c.i. pigment violet 33, c.i. pigment violet 36, c.i. pigment violet 38, c.i. pigment violet 43, c.i. pigment violet 50; c.i. vat red 1, c.i. vat red 2, c.i. vat red 10, c.i. vat red 13, c.i. vat red 15, c.i. vat red 23, c.i. vat red 29, c.i. vat red 35, etc.
Examples of the yellow colorant include: c.i. solvent yellow 19, c.i. solvent yellow 44, c.i. solvent yellow 77, c.i. solvent yellow 79, c.i. solvent yellow 81, c.i. solvent yellow 82, c.i. solvent yellow 93, c.i. solvent yellow 98, c.i. solvent yellow 103, c.i. solvent yellow 104, c.i. solvent yellow 112, c.i. solvent yellow 162; c.i. pigment orange 31, c.i. pigment orange 43; c.i. pigment yellow 1, c.i. pigment yellow 2, c.i. pigment yellow 3, c.i. pigment yellow 4, c.i. pigment yellow 5, c.i. pigment yellow 6, c.i. pigment yellow 7, c.i. pigment yellow 10, c.i. pigment yellow 11, c.i. pigment yellow 12, c.i. pigment yellow 13, c.i. pigment yellow 14, c.i. pigment yellow 15, c.i. pigment yellow 16, c.i. pigment yellow 17, c.i. pigment yellow 23, c.i. pigment yellow 24, c.i. pigment yellow 34, c.i. pigment yellow 35, c.i. pigment yellow 37, c.i. pigment yellow 42, c.i. pigment yellow 53, c.i. pigment yellow 55, c.i. pigment yellow 65, c.i. pigment yellow 73, c.i. pigment yellow 74, c.i. pigment yellow 75, c.i. pigment yellow 81, c.i. pigment yellow 83, c.i. pigment yellow 93, c.i. pigment yellow 94, c.i. pigment yellow 93, c.i. pigment yellow 94. C.i. pigment yellow 97, c.i. pigment yellow 98, c.i. pigment yellow 100, c.i. pigment yellow 101, c.i. pigment yellow 104, c.i. pigment yellow 108, c.i. pigment yellow 109, c.i. pigment yellow 110, c.i. pigment yellow 113, c.i. pigment yellow 114, c.i. pigment yellow 116, c.i. pigment yellow 117, c.i. pigment yellow 120, c.i. pigment yellow 128, c.i. pigment yellow 129, c.i. pigment yellow 133, c.i. pigment yellow 138, c.i. pigment yellow 139, c.i. pigment yellow 147, c.i. pigment yellow 150, c.i. pigment yellow 151, c.i. pigment yellow 153, c.i. pigment yellow 154, c.i. pigment yellow 155, c.i. pigment yellow 156, c.i. pigment yellow 167, c.i. pigment yellow 172, c.i. pigment yellow 173, c.i. pigment yellow 180, c.i. pigment yellow 185, c.i. pigment yellow 195; c.i. vat yellow 1, c.i. vat yellow 3, c.i. vat yellow 20, etc.
The adhesive layer of the present invention may further contain, as necessary, within a range that does not impair the effects of the present invention: crosslinking agent, crosslinking accelerator, antioxidant, plasticizer, softener, surfactant, antistatic agent, surface lubricant, leveling agent, light stabilizer, ultraviolet absorber, polymerization inhibitor, foil, antirust agent, and other additives. The above additives may be used singly or in combination of two or more.
As described above, the storage modulus G' at-20 ℃ of the pressure-sensitive adhesive layer of the present invention is 10MPa or more, preferably 50MPa or more, more preferably 100MPa or more, still more preferably 200MPa or more, and particularly preferably 300MPa or more. The storage modulus G' at-20 ℃ is a property of the adhesive layer at low temperature, and may be replaced by a property in the case of being impacted at a relatively high speed. When the storage modulus G' at a low temperature of-20℃is 10MPa or more, the impact resistance is excellent, for example, when a member to which the double-sided adhesive sheet is applied is dropped at a high speed. The storage modulus G' may be calculated using a dynamic viscoelasticity measurement (DMA) apparatus.
As described above, the storage modulus G' at 65 ℃ of the pressure-sensitive adhesive layer of the present invention is 0.05MPa or more, preferably 0.06MPa or more, more preferably 0.08MPa or more, and still more preferably 0.10MPa or more. The storage modulus G' at 65 ℃ is a property of the adhesive layer at a relatively high temperature, and may be replaced with a property in the case of receiving a low-speed impact. The adhesive layer of the present invention has a high shear adhesive strength by having a storage modulus G' at 65℃of 0.05MPa or more. The storage modulus G' may be calculated using a dynamic viscoelasticity measurement (DMA) apparatus.
The storage modulus G' at 23℃of the pressure-sensitive adhesive layer of the present invention is preferably 0.10MPa or more, more preferably 0.13MPa or more, and still more preferably 0.20MPa or more. When the storage modulus G' at 23℃is 0.10MPa or more, the alloy has moderate hardness at ordinary temperature and excellent reworkability. The storage modulus G' may be calculated using a dynamic viscoelasticity measurement (DMA) apparatus.
The glass transition temperature (Tg) of the pressure-sensitive adhesive layer of the present invention is preferably-10℃or higher, more preferably-8℃or higher, still more preferably-5℃or higher, particularly preferably-3℃or higher. When the Tg is at least-10 ℃, the storage modulus G' becomes high, and the impact resistance is further excellent. The Tg is, for example, 50℃or lower. The Tg may be calculated using a dynamic viscoelasticity measurement (DMA) device.
The peak top value of tan δ of the pressure-sensitive adhesive layer of the present invention is preferably 0.5 or more, more preferably 1.0 or more, and still more preferably 1.5 or more. When the peak top value of tan δ is 0.5 or more, the impact resistance is more excellent. The tan delta may be calculated using a dynamic viscoelasticity measurement (DMA) device.
The pressure-sensitive adhesive layer of the present invention may be in any form, and may be, for example, emulsion type, solvent type (solution type), active energy ray-curable type, hot melt type (hot melt type), or the like. Among them, the active energy ray-curable adhesive layer is preferable from the viewpoint of enabling crosslinking to be dense, impact resistance to be more excellent, shear adhesion to be higher, and reworkability to be more excellent. That is, the adhesive layer of the present invention is preferably an adhesive layer formed from an active energy ray-curable adhesive composition.
Examples of the active energy ray include: particularly, ultraviolet rays are preferable, such as ionizing radiation rays, e.g., α rays, β rays, γ rays, neutron rays, and electron rays, and ultraviolet rays. That is, the active energy ray-curable adhesive layer is preferably an ultraviolet ray-curable adhesive layer.
The adhesive layer of the present invention can be produced, for example, as follows: coating (applying) an adhesive composition for forming an adhesive layer on a release liner, and drying and curing the resulting adhesive composition layer; the adhesive composition is coated (applied) on a release liner, and the resulting adhesive composition layer is irradiated with active energy rays to be cured. Further, if necessary, the heat drying may be further performed.
As the adhesive composition (acrylic adhesive composition) for forming the adhesive layer of the present invention, for example, there can be mentioned: an acrylic pressure-sensitive adhesive composition containing an acrylic polymer as an indispensable component, an acrylic pressure-sensitive adhesive composition containing the acrylic partial polymer, the acrylic oligomer, or a monomer mixture containing a monomer component (C) as an indispensable component, or the like. The former may be, for example, a so-called solvent-type acrylic pressure-sensitive adhesive composition. The latter may be, for example, a so-called active energy ray-curable acrylic pressure-sensitive adhesive composition.
From the viewpoint of more excellent reworkability, the adhesive composition preferably contains at least: a partial polymer comprising a monomer mixture of monomer component (A) and alkyl (meth) acrylate (B), a polyfunctional monomer, and a photopolymerization initiator. The adhesive composition may further contain an acrylic oligomer, an acrylic monomer, a filler, a colorant, or the like.
(double-sided adhesive sheet)
The double-sided adhesive sheet of the present invention is composed of the adhesive layer of the present invention. The thickness of the double-sided adhesive sheet is preferably 50 μm to 500. Mu.m, more preferably 100 μm to 300. Mu.m. When the thickness is 50 μm or more, the adhesiveness to an adherend and the follow-up property are excellent. When the thickness is 500 μm or less, the thickness of the double-sided adhesive sheet can be made thinner. The thickness of the double-sided adhesive sheet refers to the thickness from one adhesive surface to the other, that is, the thickness of the adherend, excluding the release liner.
The double-sided adhesive sheet of the present invention preferably has a shear adhesion strength to one stainless steel sheet of 1.0MPa or more, more preferably 1.3MPa or more, still more preferably 1.5MPa or more, and still more preferably 2.0MPa or more, when the two adhesive surfaces are bonded by sandwiching the double-sided adhesive sheet between two stainless steel sheets and when measured under conditions of a pulling speed of 10 mm/min and a peeling angle of 0 °. When the shear adhesion force is 1.0MPa or more, the adhesion is excellent when the adhesive is adhered to an adherend. From the viewpoint of excellent reworkability, the shear adhesion is preferably 10MPa or less, more preferably 7.5MPa or less, and even more preferably 5.0MPa or less. In the case where a release liner is attached to the double-sided pressure-sensitive adhesive sheet of the present invention, the release strength is a value measured in a state after the release liner is peeled, and the detailed method is as shown in examples.
The energy (load x height) of the double-sided pressure-sensitive adhesive sheet of the present invention before any one of the stainless steel sheets is peeled off, as measured by the impact test of Du Bangshi described below, is preferably 0.3 or more, more preferably 0.4 or more, and even more preferably 0.5 or more.
< impact test >)
A frame-shaped double-sided adhesive sheet having an outer diameter of 24.5mm square and a width of 2mm was sandwiched between a stainless steel plate having a hole formed in the center of a square having a thickness of 2mm and an outer shape of 50mm square and a stainless steel plate having a square having a thickness of 3mm and an outer shape of 25mm square, and was pressure-bonded, and allowed to stand at a temperature of 50℃for 2 hours, and thereafter, was returned to normal temperature, whereby an evaluation sample was produced. Using a Du Bangshi impact tester, the drop weight and drop height of the evaluation sample were changed, energy was increased until peeling occurred, the drop height was changed 50mm to 500mm each time from 50mm in the case of 100g of the drop weight, the drop height was changed 50mm to 500mm each time from 350mm in the case of 150g of the drop weight, the drop height was changed 50mm to 500mm each time from 400mm in the case of 200g of the drop weight, and the drop height was changed 50mm to 500mm each time from 350mm in the case of 300g of the drop weight. At this time, no test was performed on the evaluated energy, and the load and the height were set so that the energy was not repeated. Then, at least any one of the stainless steel plates was calculated as load×height until the energy before peeling was dropped.
The double-sided pressure-sensitive adhesive sheet may be provided with a release liner attached to the surface (pressure-sensitive adhesive surface) of the pressure-sensitive adhesive layer until the use. The two-sided pressure-sensitive adhesive sheets may be each protected on both sides by 2 release liners, or may be each protected in a roll-like form (roll) by 1 release liner having both sides as release surfaces. The release liner is used as a protective material for the adhesive layer and is peeled off when attached to an adherend. The release liner may not be necessarily provided.
The release liner may be a conventional release paper, and examples thereof include, but are not particularly limited to: a substrate having a release treatment layer, a low-tackiness substrate comprising a fluoropolymer, a low-tackiness substrate comprising a nonpolar polymer, and the like. Examples of the substrate having the release treatment layer include: plastic films, papers, etc. obtained by surface treatment with a release treating agent such as polysiloxanes, long-chain alkyl groups, fluorine-containing, molybdenum sulfide, etc. Examples of the fluoropolymer in the low-tackiness base material containing a fluoropolymer include: polytetrafluoroethylene, polychlorotrifluoroethylene, polyvinylfluoride, polyvinylidene fluoride, tetrafluoroethylene-hexafluoropropylene copolymer, chlorofluoroethylene-vinylidene fluoride copolymer, and the like. Examples of the nonpolar polymer include: olefin resins (e.g., polyethylene, polypropylene, etc.), and the like. The release liner can be formed by a known or conventional method. In addition, the thickness of the release liner is not particularly limited.
The double-sided adhesive sheet is preferably used for attaching electric and electronic components used for attaching the components of electric and electronic devices. The double-sided adhesive sheet is particularly preferably used for the purpose of attaching components of an electric and electronic device to both adhesive surfaces of the double-sided adhesive sheet, that is, for the purpose of fixing members of the electric and electronic device to each other. The double-sided adhesive sheet may be used for any of the purposes of fixing the members to each other and the purposes of temporarily fixing the members to each other. For example, when the double-sided adhesive sheet is used for fixing or temporarily fixing components of an electrical and electronic apparatus, there are cases where the double-sided adhesive sheet must be peeled off for reworking due to occurrence of a defect in the adhesion work of the double-sided adhesive sheet, or where the double-sided adhesive sheet must be peeled off for repairing, replacing, inspecting, and recycling a member having an adherend to which the double-sided adhesive sheet is adhered. In this way, when the double-sided adhesive sheet is used for fixing or temporarily fixing a component of an electrical and electronic apparatus, for example, the frequency of removing the double-sided adhesive sheet is high.
Among them, the double-sided adhesive sheet is preferably used by bonding outer frames of optical members (particularly, electric and electronic devices) to each other. Therefore, the double-sided adhesive sheet can be satisfactorily used even when the width is 5mm or less, preferably 3mm or less.
The term "electric and electronic equipment" refers to equipment corresponding to at least one of electric equipment and electronic equipment. Examples of the electric and electronic devices include: image display devices such as liquid crystal displays, electroluminescent displays, and plasma displays; portable electronic devices, and the like.
Examples of the portable electronic device include: a mobile phone, a smart phone, a tablet personal computer, a notebook personal computer, various wearable devices (for example, a wrist wearing type worn on a wrist like a wristwatch, a modularized type worn on a part of a body using a clip, a band, or the like, an eye wearing type including a glasses type (monocular type, binocular type, also including a head wearing type), a clothing type worn on a shirt, a sock, a hat, or the like in the form of a jewelry, an ear wearing type worn on an ear like an earphone, or the like), a digital camera, a digital video camera, an audio device (portable music player, an IC recorder, or the like), a calculator (electronic calculator, or the like), a portable game machine, an electronic dictionary, an electronic notepad, an electronic book, an in-vehicle information device, a portable radio, a portable television, a portable printer, a portable scanner, a portable modem, or the like. In this specification, "portable" means that portability is insufficient only in that it can be carried, and that it has a level that an individual (a standard adult) can relatively easily carry. The double-sided adhesive sheet is used, for example, such that an adhesive layer adheres to a member of the portable electronic device.
Examples
The present invention will be described in more detail with reference to the following examples, but the present invention is not limited to these examples.
Production example 1: synthesis of slurry (1)
Butyl Acrylate (BA) as monomer component: 70 parts by mass of Acrylic Acid (AA): 7 parts by mass and isobornyl acrylate (IBXA, tg:97 ℃ C.): 23 parts by mass of a mixture of monomers (monomer composition) in a liquid state, 2-dimethoxy-1, 2-diphenylethan-1-one (trade name "OMNIRAD651", manufactured by IGM Resins b.v.) was added as a photopolymerization initiator: 0.05 part by mass, and then pulse-irradiating ultraviolet until the viscosity (BH viscometer No. 5 spindle, 10rpm, measurement temperature: 30 ℃) reaches about 15 Pa.s, thereby obtaining a slurry (partial polymer) containing a partially polymerized partial polymer (polymerization rate: about 8%) of the monomer component.
Production example 2: synthesis of slurry (2)
Butyl Acrylate (BA) as monomer component: 70 parts by mass of Acrylic Acid (AA): 7 parts by mass and tetrahydrodicyclopentadiene acrylate (DCPA, tg: about 100 ℃): 23 parts by mass of a mixture of monomers (monomer composition) in a liquid state, 2-dimethoxy-1, 2-diphenylethan-1-one (trade name "OMNIRAD651", manufactured by IGM Resins b.v.) was added as a photopolymerization initiator: 0.05 part by mass, and then pulse-irradiating ultraviolet until the viscosity (BH viscometer No. 5 spindle, 10rpm, measurement temperature: 30 ℃) reaches about 15 Pa.s, thereby obtaining a slurry (partial polymer) containing a partially polymerized partial polymer (polymerization rate: about 8%) of the monomer component.
Production example 3: synthesis of slurry (3)
Butyl Acrylate (BA) as monomer component: 70 parts by mass of Acrylic Acid (AA): 7 parts by mass and cyclohexyl acrylate (CHA, tg:15 ℃ C.). 23 parts by mass of a mixture of monomers (monomer composition) in a liquid state, 2-dimethoxy-1, 2-diphenylethan-1-one (trade name "OMNIRAD651", manufactured by IGM Resins b.v.) was added as a photopolymerization initiator: 0.05 part by mass, and then pulse-irradiating ultraviolet until the viscosity (BH viscometer No. 5 spindle, 10rpm, measurement temperature: 30 ℃) reaches about 15 Pa.s, thereby obtaining a slurry (partial polymer) containing a partially polymerized partial polymer (polymerization rate: about 8%) of the monomer component.
Production example 4: synthesis of slurry (4)
Butyl Acrylate (BA) as monomer component: 78 parts by mass of Acrylic Acid (AA): 7 parts by mass and N-acryloylmorpholine (ACMO, tg: about 145 ℃ C.). 15 parts by mass of a monomer mixture (monomer composition) in a liquid state, to which 2, 2-dimethoxy-1, 2-diphenylethan-1-one (trade name "OMNIRAD651", manufactured by IGM Resins B.V.) was added as a photopolymerization initiator: 0.05 part by mass, and then pulse-irradiating ultraviolet until the viscosity (BH viscometer No. 5 spindle, 10rpm, measurement temperature: 30 ℃) reaches about 15 Pa.s, thereby obtaining a slurry (partial polymer) containing a partially polymerized partial polymer (polymerization rate: about 8%) of the monomer component.
Production example 5: synthesis of slurry (5)
Butyl Acrylate (BA) as monomer component: 70 parts by mass of Acrylic Acid (AA): 10 parts by mass and isobornyl acrylate (IBXA, tg:97 ℃ C.): 20 parts by mass of a mixture of monomers (monomer composition) in a liquid state, 2-dimethoxy-1, 2-diphenylethan-1-one (trade name "OMNIRAD651", manufactured by IGM Resins B.V.) was added as a photopolymerization initiator: 0.05 part by mass, and then pulse-irradiating ultraviolet until the viscosity (BH viscometer No. 5 spindle, 10rpm, measurement temperature: 30 ℃) reaches about 15 Pa.s, thereby obtaining a slurry (partial polymer) containing a partially polymerized partial polymer (polymerization rate: about 8%) of the monomer component.
Production example 6: synthesis of slurry (6)
Butyl Acrylate (BA) as monomer component: 77 parts by mass of Acrylic Acid (AA): 8 parts by mass and tetrahydrodicyclopentadiene acrylate (DCPA, tg: about 100 ℃): 15 parts by mass of a monomer mixture (monomer composition) in a liquid state, 2-dimethoxy-1, 2-diphenylethan-1-one (trade name "OMNIRAD651", manufactured by IGM Resins B.V.) was blended as a photopolymerization initiator: 0.05 part by mass, and then pulse-irradiating ultraviolet until the viscosity (BH viscometer No. 5 spindle, 10rpm, measurement temperature: 30 ℃) reaches about 15 Pa.s, thereby obtaining a slurry (partial polymer) containing a partially polymerized partial polymer (polymerization rate: about 8%) of the monomer component.
Production example 7: synthesis of slurry (7)
Butyl Acrylate (BA) as monomer component: 60 parts by mass of Acrylic Acid (AA): 10 parts by mass and tetrahydrodicyclopentadiene acrylate (DCPA, tg: about 100 ℃): 30 parts by mass of a mixture of monomers (monomer composition) in a liquid state, 2-dimethoxy-1, 2-diphenylethan-1-one (trade name "OMNIRAD651", manufactured by IGM Resins B.V.) was added as a photopolymerization initiator: 0.05 part by mass, and then pulse-irradiating ultraviolet until the viscosity (BH viscometer No. 5 spindle, 10rpm, measurement temperature: 30 ℃) reaches about 15 Pa.s, thereby obtaining a slurry (partial polymer) containing a partially polymerized partial polymer (polymerization rate: about 8%) of the monomer component.
Production example 8: synthesis of slurry (8)
Butyl Acrylate (BA) as monomer component: 55 parts by mass of Acrylic Acid (AA): 10 parts by mass and tetrahydrodicyclopentadiene acrylate (DCPA, tg: about 100 ℃): 35 parts by mass of a monomer mixture (monomer composition) in a liquid state, to which 2, 2-dimethoxy-1, 2-diphenylethan-1-one (trade name "OMNIRAD651", manufactured by IGM Resins b.v.) was added as a photopolymerization initiator: 0.05 part by mass, and then pulse-irradiating ultraviolet until the viscosity (BH viscometer No. 5 spindle, 10rpm, measurement temperature: 30 ℃) reaches about 15 Pa.s, thereby obtaining a slurry (partial polymer) containing a partially polymerized partial polymer (polymerization rate: about 8%) of the monomer component.
Production example 9: synthesis of slurry (9)
Butyl Acrylate (BA) as monomer component: 95 parts by mass and Acrylic Acid (AA): 5 parts by mass of a mixture of monomers (monomer composition) in a liquid state, 2-dimethoxy-1, 2-diphenylethan-1-one (trade name "OMNIRAD651", manufactured by IGM Resins B.V.) was added as a photopolymerization initiator: 0.05 part by mass, and then pulse-irradiating ultraviolet until the viscosity (BH viscometer No. 5 spindle, 10rpm, measurement temperature: 30 ℃) reaches about 15 Pa.s, thereby obtaining a slurry (partial polymer) containing a partially polymerized partial polymer (polymerization rate: about 8%) of the monomer component.
Production example 10: synthesis of slurry (10)
Butyl Acrylate (BA) as monomer component: 80 parts by mass of Acrylic Acid (AA): 5 parts by mass and isobornyl acrylate (IBXA, tg:97 ℃ C.). 15 parts by mass of a monomer mixture (monomer composition) in a liquid state, to which 2, 2-dimethoxy-1, 2-diphenylethan-1-one (trade name "OMNIRAD651", manufactured by IGFRESINS B.V.) was added as a photopolymerization initiator: 0.05 part by mass, and then pulse-irradiating ultraviolet until the viscosity (BH viscometer No. 5 spindle, 10rpm, measurement temperature: 30 ℃) reaches about 15 Pa.s, thereby obtaining a slurry (partial polymer) containing a partially polymerized partial polymer (polymerization rate: about 8%) of the monomer component.
Production example 11: synthesis of acrylic oligomers
To the flask was added tetrahydrodicyclopentadiene methacrylate (DCPMA, tg:175 ℃ C.): 60 parts by mass of Methyl Methacrylate (MMA): 40 parts by mass of alpha-thioglycerol: 3 parts by mass of 2,2' -azobisisobutyronitrile: 0.2 parts by mass and ethyl acetate: 65 parts by mass. The flask was sufficiently filled with nitrogen, polymerized at 70℃for 5 hours, and then further added with 0.1 parts by mass of 2,2' -azobisisobutyronitrile, and polymerized at 80℃for 8 hours. Thereafter, ethyl acetate was distilled off from the reaction solution, and further dried by a vacuum dryer, whereby an acrylic oligomer (weight average molecular weight: 5080) was obtained.
Example 1
Slurry (1) obtained in production example 1 was prepared: 100 parts by mass of a black pigment (trade name "Multilac A903", manufactured by Toyocor Co., ltd.) containing carbon black: 0.2 part by mass of a polyethylene powder (trade name "Flowsen UF-80", manufactured by Sumitomo Co., ltd.) as a filler: 2 parts by mass of 1, 6-hexanediol diacrylate (HDDA): 0.12 part by mass and 2, 2-dimethoxy-1, 2-diphenylethan-1-one (trade name "OMNIRAD651", manufactured by IGM Resins B.V..) as a photopolymerization initiator: 0.1 part by mass of an acrylic pressure-sensitive adhesive composition was obtained by mixing the components uniformly using a disperser and then defoaming the mixture.
The obtained acrylic adhesive composition was coated on a polyethylene terephthalate film (product name "mrf#38", manufactured by mitsubishi chemical corporation) having a thickness of 38 μm obtained by subjecting one surface to a release treatment with polysiloxane using an applicator so that the thickness of the adhesive layer became 200 μm, thereby forming a coating layer.
Next, the coating layer was covered so that the release treated surface of a polyethylene terephthalate film (product name "mre#25", manufactured by mitsubishi chemical corporation) having a thickness of 25 μm, which was obtained by subjecting one surface to a release treatment with polysiloxane, became the coating layer side, thereby blocking oxygen. Thereafter, the film was irradiated with a black light lamp for 180 seconds with an illuminance of 4mW/cm from the upper surface thereof 2 (UV checker "UVR-T1", manufactured by Topcon, co., ltd., maximum sensitivity at the time of measurement was about 350 nm), thereby forming an adhesive layer having a thickness of 200. Mu.m, thereby manufacturing a double-sided adhesive sheet.
Example 2
Except that silicone rubber particles (trade name "Trefil E-606", manufactured by eastern corporation) were used as the filler: a double-sided pressure-sensitive adhesive sheet of example 2 was produced in the same manner as in example 1, except for 2 parts by mass.
Example 3
Except that polyethylene particles (trade name "Flow beads FBRP", manufactured by sumitomo refinement corporation) were used as the filler: a double-sided pressure-sensitive adhesive sheet of example 3 was produced in the same manner as in example 1, except for 2 parts by mass.
Example 4
Slurry (1) obtained in production example 1 was prepared: 100 parts by mass of the acrylic oligomer obtained in production example 11: 5 parts by mass of a black pigment (trade name "Multilac A903", manufactured by Toyocor Co., ltd.) containing carbon black: 1 part by mass of polyethylene powder (trade name "Flowsen UF-80", manufactured by sumitomo refinement corporation) as a filler: 2 parts by mass of 1, 6-hexanediol diacrylate (HDDA): 0.12 part by mass of an ultraviolet curable urethane acrylate oligomer (trade name "ultraviolet UV-3000B", manufactured by mitsubishi chemical Co., ltd.): 3 parts by mass and 2, 2-dimethoxy-1, 2-diphenylethan-1-one (trade name "OMNIRAD651", manufactured by IGM Resins B.V.): 0.5 parts by mass, and then uniformly mixed using a disperser, and then defoamed, to obtain an acrylic adhesive composition.
A double-sided adhesive sheet of example 4 was produced in the same manner as in example 1, except that the acrylic adhesive composition obtained above was used.
Example 5
Slurry (1) obtained in production example 1 was prepared: 100 parts by mass of cyclohexyl acrylate (CHA): 13 parts by mass of Acrylic Acid (AA): 2 parts by mass of a black pigment (trade name "Multilac A903", manufactured by Toyocor Co., ltd.) containing carbon black: 0.2 part by mass of a polyethylene powder (trade name "Flowsen UF-80", manufactured by Sumitomo Co., ltd.) as a filler: 2 parts by mass of 1, 6-hexanediol diacrylate (HDDA): 0.12 part by mass and 2, 2-dimethoxy-1, 2-diphenylethan-1-one (trade name "OMNIRAD651", manufactured by IGM Resins B.V..) as a photopolymerization initiator: 0.1 part by mass of an acrylic pressure-sensitive adhesive composition was obtained by mixing the components uniformly using a disperser and then defoaming the mixture.
A double-sided adhesive sheet of example 5 was produced in the same manner as in example 1, except that the acrylic adhesive composition obtained above was used.
Example 6
A double-sided adhesive sheet of example 6 was produced in the same manner as in example 1, except that the blending amount of the black pigment was set to 0.5 parts by mass.
Example 7
A double-sided adhesive sheet of example 7 was produced in the same manner as in example 1, except that the slurry (2) obtained in production example 2 was used instead of the slurry (1) obtained in production example 1.
Example 8
A double-sided adhesive sheet of example 8 was produced in the same manner as in example 7, except that the blending amount of the photopolymerization initiator was set to 0.05 parts by mass.
Example 9
A double-sided adhesive sheet of example 9 was produced in the same manner as in example 1, except that the slurry (3) obtained in production example 3 was used instead of the slurry (1) obtained in production example 1.
Example 10
A double-sided adhesive sheet of example 10 was produced in the same manner as in example 1, except that the slurry (4) obtained in production example 4 was used instead of the slurry (1) obtained in production example 1.
Example 11
Slurry (1) obtained in production example 1 was prepared: 100 parts by mass of the acrylic oligomer obtained in production example 11: 5 parts by mass of a black pigment (trade name "Multilac A903", manufactured by Toyocor Co., ltd.) containing carbon black: 1 part by mass of polyethylene powder (trade name "Flowsen UF-80", manufactured by sumitomo refinement corporation) as a filler: 2 parts by mass of 1, 6-hexanediol diacrylate (HDDA): 0.12 part by mass and 2, 2-dimethoxy-1, 2-diphenylethan-1-one (trade name "OMNIRAD651", manufactured by IGM Resins B.V..) as a photopolymerization initiator: 0.5 parts by mass, and then uniformly mixed using a disperser, and then defoamed, to obtain an acrylic adhesive composition.
A double-sided adhesive sheet of example 11 was produced in the same manner as in example 1, except that the acrylic adhesive composition obtained above was used.
Example 12
A double-sided adhesive sheet of example 12 was produced in the same manner as in example 11, except that the slurry (5) obtained in production example 5 was used instead of the slurry (1) obtained in production example 1.
Example 13
A double-sided adhesive sheet of example 13 was produced in the same manner as in example 1, except that the slurry (6) obtained in production example 6 was used instead of the slurry (1) obtained in production example 1.
Example 14
A double-sided adhesive sheet of example 14 was produced in the same manner as in example 1, except that the slurry (7) obtained in production example 7 was used instead of the slurry (1) obtained in production example 1.
Example 15
A double-sided adhesive sheet of example 15 was produced in the same manner as in example 1, except that the slurry (8) obtained in production example 8 was used instead of the slurry (1) obtained in production example 1.
Example 16
A double-sided adhesive sheet of example 16 was produced in the same manner as in example 15, except that spherical silicone rubber powder (trade name "DOWSIL EP-2600", manufactured by Tao Shidong co.) was used instead of polyethylene powder (trade name "Flowsen UF-80", manufactured by sumitomo refinement co.) as a filler.
Comparative example 1
A double-sided adhesive sheet of comparative example 1 was produced in the same manner as in example 11, except that the slurry (9) obtained in production example 9 was used instead of the slurry (1) obtained in production example 1.
Comparative example 2
A double-sided adhesive sheet of comparative example 2 was produced in the same manner as in example 11, except that the slurry (10) obtained in production example 10 was used instead of the slurry (1) obtained in production example 1.
< evaluation >
The double-sided adhesive sheets obtained in examples and comparative examples were evaluated as follows. The results are shown in the table. The amounts of the components in the tables are expressed in parts by mass.
(1) Dynamic viscoelasticity measurement
By overlapping a plurality of double-sided adhesive sheets produced in examples and comparative examples, an adhesive layer having a thickness of about 2mm was produced. The adhesive layer was punched out into a disk shape having a diameter of 7.9mm to obtain a sample, the sample was sandwiched between parallel plates and fixed, and a viscoelasticity tester (trade name "ARES rheometer", manufactured by TA Instruments) was used under the environment of 23℃and 50% RH to measure dynamic viscoelasticity under the following conditions, and peak top values of storage modulus G ' (-20 ℃) and storage modulus G ' (23 ℃), storage modulus G ' (65 ℃), glass transition temperature and tan. Delta. Were calculated.
Measurement mode: shear mode
Temperature range: -70-150 DEG C
Heating rate: 5 ℃/min
Measuring frequency: 1Hz
(2) Shear adhesive force
The double-sided adhesive sheets produced in examples and comparative examples were cut into dimensions of 20mm×20mm, thereby producing measurement samples. The adhesive surfaces of the measurement samples were each superposed on the surfaces of two stainless steel plates at 23℃under 50% RH, and a 2kg roller was reciprocated and pressure-bonded once. The resultant was left under the same environment for 30 minutes, and then the shear adhesion was measured using a tensile tester under conditions of a pulling speed of 10 mm/minute and a peeling angle of 0 °. Specifically, as shown in fig. 2, one adhesive surface 10a of the measurement sample 10 is bonded to the stainless steel plate 21, and the other adhesive surface 10b of the measurement sample 10 is bonded to the stainless steel plate 22, and pressure-bonding is performed. The resulting sheet was pulled in the direction of the arrow (i.e., in the shearing direction) in FIG. 2 at the above-mentioned speed, and the peel strength was measured every 20 mm. Times.20 mm. From the obtained values, shear adhesion force [ MPa ] was obtained. As a tensile tester, a universal tensile compression tester (product name "TG-1kN", manufactured by Meibuya Co., ltd.) was used.
(3) Impact resistance
The double-sided pressure-sensitive adhesive sheets produced in examples and comparative examples were punched out in a frame shape having an outer diameter of 24.5mm square and a width of 2mm in a state of being sandwiched between release liners. Thereafter, the release liner was peeled from the double-sided adhesive sheet, sandwiched between a stainless steel plate having a hole formed in the center of a square having a thickness of 2mm and an external shape of 50mm and a stainless steel plate having a square having a thickness of 3mm and an external shape of 25mm, and pressure-bonded, allowed to stand in an atmosphere at a temperature of 50 ℃ for 2 hours, and thereafter returned to normal temperature, to prepare an evaluation sample. A cylindrical measuring table having a length of 50mm, an outer diameter of 49mm and an inner diameter of 43mm was set on a base of a Du Bangshi impact tester (manufactured by Toyo Seiki Seisaku-Sho-K.K.), and a test piece was placed thereon with a square stainless steel plate (stainless steel plate without holes) as the lower side. A stainless steel core with a tip radius of 3.1mm was placed on the test piece, the drop weight and drop height were changed, energy was increased until peeling occurred, the drop height was changed 50mm to 500mm each time from 50mm in the case of a drop weight of 100g, the drop height was changed 50mm to 500mm each time from 350mm in the case of a drop weight of 150g, the drop height was changed 50mm to 500mm each time from 400mm in the case of a drop weight of 200g, the drop height was changed 50mm to 500mm each time from 400mm in the case of a drop weight of 300g, and the drop height was changed 50mm to 500mm each time from 350mm each time. At this time, no test was performed on the evaluated energy, and the load and the height were set so that the energy was not repeated. Thereafter, the energy before peeling of at least any one of the stainless steel plates was calculated as the load x height.
/>
As shown in tables 1 and 2, it was confirmed that the double-sided adhesive sheet of the present invention was high in shear adhesion and excellent in impact resistance. On the other hand, the ratio of the structural unit derived from the monomer component (a) in the acrylic polymer contained in the double-sided adhesive sheet is low, and in the case where the storage modulus G 'at-20 ℃ and the storage modulus G' at 65 ℃ of the adhesive layer are low (comparative examples 1 and 2), the shear adhesion is sometimes low and the impact resistance is poor.
Description of the reference numerals
1. Double-sided adhesive sheet
2. Adhesive layer
3. 4 Release liner
10. Measuring samples
10a, 10b adhesive face
21. 22 stainless steel plate

Claims (10)

1. A double-sided adhesive sheet comprising an adhesive layer,
the adhesive layer is an acrylic adhesive layer comprising an acrylic polymer as a base polymer,
the acrylic polymer comprises structural units derived from a monomer component (A) having a homopolymer with a glass transition temperature of 0 ℃ or higher and a non-aromatic ring,
the proportion of the structural unit derived from the monomer component (A) in the acrylic polymer is 5% by mass or more,
the adhesive layer has a storage modulus G 'at-20 ℃ of 10MPa or more, and the adhesive layer has a storage modulus G' at 65 ℃ of 0.05MPa or more.
2. The double-sided adhesive sheet according to claim 1, wherein the acrylic polymer comprises a structural unit derived from an alkyl (meth) acrylate (B) having a linear or branched alkyl group having 2 to 7 carbon atoms.
3. The double-sided adhesive sheet according to claim 2, wherein the alkyl (meth) acrylate (B) contains butyl (meth) acrylate, and the proportion of structural units derived from butyl (meth) acrylate in the acrylic polymer is 50 mass% or more.
4. The double-sided adhesive sheet according to any one of claims 1 to 3, wherein the adhesive layer is an active energy ray-curable adhesive layer.
5. The double-sided adhesive sheet according to any one of claims 1 to 4, wherein the acrylic polymer contains a polyfunctional monomer copolymerizable with a monomer component forming the acrylic polymer as a constituent monomer component.
6. The double-sided adhesive sheet according to any one of claims 1 to 5, wherein the non-aromatic ring is an aliphatic hydrocarbon ring and/or a nitrogen atom-containing heterocycle.
7. The double-sided adhesive sheet according to any one of claims 1 to 6, wherein the adhesive layer has a glass transition temperature of-10 ℃ or higher.
8. The double-sided adhesive sheet according to any one of claims 1 to 7, wherein the double-sided adhesive sheet has a shear adhesion force to one stainless steel sheet of 1.0MPa or more when the two adhesive surfaces are bonded by sandwiching the double-sided adhesive sheet between the two stainless steel sheets and when measured under conditions of a pulling speed of 10 mm/min and a peeling angle of 0 °.
9. The double-sided adhesive sheet according to any one of claims 1 to 8, wherein the double-sided adhesive sheet is used for fixation of members in an electric and electronic apparatus to each other.
10. An electrical and electronic apparatus having the double-sided adhesive sheet according to claim 9,
the double-sided adhesive sheet fixes the members to each other by two adhesive faces.
CN202280044676.3A 2021-07-06 2022-06-16 Double-sided adhesive sheet Pending CN117561313A (en)

Applications Claiming Priority (4)

Application Number Priority Date Filing Date Title
JP2021-112343 2021-07-06
JP2022-039920 2022-03-15
JP2022039920A JP2023008796A (en) 2021-07-06 2022-03-15 double-sided adhesive sheet
PCT/JP2022/024105 WO2023282009A1 (en) 2021-07-06 2022-06-16 Double-sided pressure-sensitive adhesive sheet

Publications (1)

Publication Number Publication Date
CN117561313A true CN117561313A (en) 2024-02-13

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Family Applications (1)

Application Number Title Priority Date Filing Date
CN202280044676.3A Pending CN117561313A (en) 2021-07-06 2022-06-16 Double-sided adhesive sheet

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CN (1) CN117561313A (en)

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