TWI825392B - Adhesive materials, adhesive sheets, flexible laminated components and mobile terminals - Google Patents

Abstract

Problem to be solved: Provide an adhesive material that, when used to bond flexible members constituting a flexible laminated member, can suppress bending even if the flexible laminated member is repeatedly bent. cracks or deformation. Solution: An adhesive material, characterized in that it is used to bond one flexible component to another flexible component, and the adhesive material is a (meth)acrylic copolymer containing reactive functional groups. and a cured product of an adhesive composition of a cross-linking agent. The (meth)acrylic copolymer is obtained through living free radical polymerization, and its molecular weight distribution is below 3.0. The shear of the adhesive material at 23°C The energy storage elastic modulus is 0.8×10 ⁴ ~30×10 ⁴ Pa, and the Young’s modulus of the adhesive material is 10~1000kPa. After the adhesive material is elongated until the tensile stress reaches 50kPa, the tensile stress is released. When the elongation and contraction test is repeated 10 times, the ratio of the elastic modulus at the tenth contraction to the elastic modulus at the first contraction is 60% or more.

Description

Adhesive materials, adhesive sheets, flexible laminated components and mobile terminals

The present invention relates to an adhesive material for bonding a flexible member to another flexible member that constitutes a flexible laminated member that can be bent repeatedly.

In various displays or touch panels such as televisions, mobile phones, and smart phones, adhesive materials are usually used to join their constituent components to each other. The adhesive material is provided in the form of, for example, an adhesive sheet with a base material having an adhesive material layer on a supporting base material, or an adhesive sheet without a base material without a supporting base material, so as to adhere the components to each other.

On the other hand, in recent years, in image display devices such as liquid crystal display devices and organic electroluminescence (organic EL) display devices, flexible displays that are used in repeated bending have attracted attention. Among the flexible displays, there are foldable displays that can be folded and rollable displays that can be rolled into a tube shape. They are expected to be used in mobile terminals such as smartphones and tablet terminals, and in fixed displays that can be stored. .

In such a flexible display, for example, Patent Document 1 discloses a repetitive flexing device as an adhesive material for bonding a flexible member constituting a member that repeatedly bends and stretches and other flexible members. Using an adhesive, the ratio of the shear stress (the shear stress after 60 seconds when the surface on one side of the adhesive layer and the surface on the other side of the adhesive layer are displaced 1000% in opposite directions relative to the maximum shear stress when the displacement is 1000% The ratio of shear stress) and the sol fraction (Gel Fraction) are controlled within a predetermined range (refer to the patent document (claim 1)).

[Prior technical literature]

[Patent Document]

[Patent Document 1] Japanese Patent Application Publication No. 2019-108498

In the conventional flexible member with an adhesive layer, when it is repeatedly bent, the recovery from the bent state to the original state is insufficient. Therefore, when a flexible laminated member is repeatedly bent, floating or peeling may occur at the interface between the adhesive layer and the flexible member at the bend, or appearance defects such as corrugations at the bend may occur.

The present invention was made in view of the above circumstances, and an object thereof is to provide an adhesive material that, when used to bond flexible members constituting a flexible laminated member, can prevent the flexible laminated member from bending repeatedly even if the flexible laminated member is repeatedly bent. It can still suppress appearance defects such as cracks or ripples at bends.

The adhesive material of the present invention that can solve the above problems is characterized in that it is used to bond one flexible member and another flexible member, and the adhesive material contains (methyl) having a reactive functional group. A cured product of an adhesive composition of an acrylic copolymer and a cross-linking agent. The (meth)acrylic copolymer is obtained through living radical polymerization, and its molecular weight distribution (Mw/Mn) is 3.0 or less. The shear energy storage elastic modulus of the adhesive material at 23°C is 0.8×10 ⁴ Pa ~ 30 × 10 ⁴ Pa. The Young's modulus of the adhesive material is 10 kPa ~ 1000 kPa. The adhesive material is stretched until it is stretched. After the tensile stress reaches 50kPa, the tensile stress is released and the test is repeated 10 times. The ratio of the elastic modulus at the 10th contraction to the elastic modulus at the 1st contraction is 60%. above.

In copolymers produced through free radical polymerization, the molecular chains obtained are not uniform in length, and the composition of each molecular chain is also uneven. Therefore, it is judged that when this copolymer is used in an adhesive material, the distance between the cross-linked points cross-linked by the cross-linking agent is uneven, causing the obtained adhesive material to have locations with different local elastic moduli. . According to research, if the adhesive material with uneven distance between cross-linking points is repeatedly bent and stretched, it will be prone to local fracture and plastic deformation due to its uneven elastic modulus.

The (meth)acrylic copolymer produced by living radical polymerization has a narrow molecular weight distribution and a consistent composition of each molecular chain. That is, the number of reactive functional groups in each molecular chain of the (meth)acrylic copolymer is the same. Therefore, when such a (meth)acrylic copolymer is used in an adhesive material, the distances between the cross-linked points cross-linked by the cross-linking agent are uniform, so that the obtained cured product (adhesive material) has an overall Almost the same elastic modulus. Furthermore, since the entire adhesive material has almost the same elastic modulus, even if the adhesive material is repeatedly bent and stretched, local fractures can be suppressed, and even if the adhesive material is repeatedly bent and stretched, the reduction in the restoring force to the original shape can be suppressed.

Furthermore, if the adhesive material has a predetermined shear energy storage elastic modulus and Young's modulus, and the elastic modulus maintenance rate is high during repeated shrinkage tests, the adhesive material can follow the elasticity of the flexible member. Deformation of bending and stretching. Therefore, by using the adhesive material of the present invention, the interface between the adhesive layer and the flexible member at the bend of the flexible laminated member can be prevented from floating or peeling, and the appearance of cracks, ripples, etc. can be suppressed. defect.

When the adhesive material of the present invention is used to bond flexible members constituting a flexible laminated member, even if the flexible laminated member is repeatedly bent, the adhesive layer and the flexible member will not be bonded at the bend. Floating or peeling occurs at the interface between components, which can suppress appearance defects such as cracks and ripples.

10: Adhesive sheet

12: Adhesive layer

14: First flexible sheet member

16: Second flexible sheet member

20: Flexible laminated components

22: First flexible member

24: Second flexible member

30: Flexible laminated components

32: Covering film (first flexible member)

32a: Covering film substrate

32b:hard coating

34: Polarizing film (second flexible member)

[Fig. 1] is a schematic cross-sectional view of an example of the adhesive sheet of the present invention.

[Fig. 2] is a schematic cross-sectional view of one example of the flexible laminated member of the present invention.

[Fig. 3] is a schematic cross-sectional view of one example of the flexible laminated member of the present invention.

An example of a preferred mode for implementing the present invention will be described below. However, the following implementation types are only examples. The present invention is not limited to the following embodiments.

In the present invention, "(meth)acrylic acid" refers to "one of acrylic acid and methacrylic acid", and "(meth)acrylate" refers to "at least one of acrylic acid ester and methacrylic acid ester". one". "(Meth)acrylamide" means "at least one of acrylic acid and methacrylic acid". "Vinyl monomer" refers to a monomer with a free radical polymerizable carbon-carbon double bond in the molecule. "Structural unit derived from vinyl monomer" refers to a structural unit in which a radically polymerizable carbon-carbon double bond of a vinyl monomer is polymerized to form a carbon-carbon single bond. "Structural unit derived from (meth)acrylate" refers to a structural unit in which a radically polymerizable carbon-carbon double bond of (meth)acrylate is polymerized to form a carbon-carbon single bond. "From "Structural unit of (meth)acrylic acid monomer" refers to the structural unit in which the radically polymerizable carbon-carbon double bond of the (meth)acrylic acid monomer is polymerized to form a carbon-carbon single bond.

[Adhesive material]

The adhesive material of the present invention is used to bond one flexible member and another flexible member, and the flexible member forms a flexible laminated member that can be bent repeatedly. The adhesive material is characterized in that it is a cured product of an adhesive composition containing a (meth)acrylic copolymer with reactive functional groups and a cross-linking agent, and the (meth)acrylic copolymer is reactive through It is obtained by free radical polymerization, and its molecular weight distribution (Mw/Mn) is below 3.0. In addition, the shear energy storage elastic modulus of the adhesive material at 23°C is 0.8×10 ⁴ Pa ~ 30 × 10 ⁴ Pa, and the Young's modulus of the adhesive material is 10 kPa ~ 1000 kPa, and the adhesive material After the material is elongated until the tensile stress reaches 50kPa, the tensile stress is released to allow it to shrink. When the elongation and contraction test is repeated 10 times, the ratio of the elastic modulus at the 10th contraction to the elastic modulus at the 1st contraction. The system is above 60%.

The shear energy storage elastic modulus (G') of the adhesive material at 23°C is 0.8×10 ⁴ Pa or more, preferably 1.0×10 ⁴ Pa or more, more preferably 2.0×10 ⁴ Pa or more, and is 30×10 ⁴ Pa or less, preferably 20×10 ⁴ Pa or less, more preferably 10×10 ⁴ Pa or less, most preferably 8.0×10 ⁴ Pa or less. When the shear storage modulus (G') is above 0.8×10 ⁴ Pa, the adhesive material has moderate softness and good shape followability. When it is below 30×10 ⁴ Pa, the cohesion and adhesiveness of the adhesive material become better. The measurement method of the shear storage elastic modulus (G') of the adhesive material is as described below.

The shear loss modulus (G”) of the adhesive material at 23°C is preferably 0.40×10 ⁴ Pa or more, more preferably 0.50×10 ⁴ Pa or more, most preferably 1.0×10 ⁴ Pa or more, and is relatively It is preferably below 27×10 ⁴ Pa, more preferably below 18×10 ⁴ Pa, and most preferably below 9.0×10 ⁴ Pa. When the shear loss modulus (G”) is above 0.40×10 ⁴ Pa, the adhesive material has It has moderate softness and good ability to follow the shape of the adhered object. When it is below 27×10 ⁴ Pa, the cohesion and adhesion of the adhesive material become better. The measurement method of the shear loss elastic modulus (G”) of the adhesive material is as described below.

The stress immediately after applying shear stress to the adhesive material to achieve a shear strain of 200% is preferably 5.0×10 ⁴ Pa or more, more preferably 7.0×10 ⁴ Pa or more, and most preferably 10 ×10 ⁴ Pa or more, preferably 150 × 10 ⁴ Pa or less, more preferably 100 × 10 ⁴ Pa or less, most preferably 50 × 10 ⁴ Pa or less. When the stress is 5.0×10 ⁴ Pa or above, the cohesion and adhesion of the adhesive material become better. When the stress is 150×10 ⁴ Pa or less, the adhesion is good.

When a shear stress is applied to the adhesive material to achieve a shear strain of 200% and maintained for 10 minutes, the stress is preferably 0.50×10 ⁴ Pa or more, more preferably 0.70×10 4 Pa or more, and the optimum is 0.70×10 ⁴ Pa or more. It is preferably 1.0×10 ⁴ Pa or more, more preferably 8.0×10 ⁴ Pa or less, more preferably 5.0×10 ⁴ Pa or less, most preferably 2.0×10 ⁴ Pa or less. When the stress is above 0.50×10 ⁴ Pa, the cohesion and adhesion of the adhesive material become better. When the stress is 8.0×10 ⁴ Pa or less, when the flexible laminate is bent by using the adhesive material, the stress applied to the bending part can be well relaxed and reduced, so the bending can be suppressed. Cracks occur in the flexible member, and floating or peeling occurs at the interface between the adhesive layer and the flexible member.

When a shear stress is applied to the adhesive material to achieve a shear strain of 200% and maintained for 10 minutes, the recovery rate after the stress is released and left for 10 minutes is preferably 60% or more. When the recovery rate is 60% or more, the deformation caused when the flexible laminated member is stretched can easily return to its original shape after the flexible laminated member is left in a bent state for a long time, so appearance defects such as ripples at the bends can be suppressed. In addition, the recovery rate is more preferably 65% or more, still more preferably 75% or more, still more preferably 85% or more, and the upper limit is 100%.

The Young's modulus of the adhesive material is 10kPa or more, preferably 25kPa or more, more preferably 50kPa or more, most preferably 90kPa or more, and 1000kPa or less, preferably 600kPa or less, more preferably 500kPa or less, most preferably is below 400kPa. When the Young's modulus is 10kPa or more, appearance defects such as waviness can be suppressed even in high-temperature environments, and when it is below 1000kPa, floating or peeling during bending can be suppressed even in low-temperature environments.

When the adhesive material is stretched until the tensile stress reaches 50kPa, the tensile stress is released to cause it to shrink. When the elongation and contraction test is repeated 10 times, the elastic modulus at the 10th contraction is relative to the elastic modulus at the 1st contraction. The ratio of carbon modulus is 60% or more. When the ratio is 60% or more, even when the adhesive material is repeatedly stretched, the amount of plastic deformation of the adhesive material is small. Therefore, when used in a flexible laminated member, appearance defects such as deformation marks at bends can be suppressed. In addition, the ratio is preferably 70% or more, more preferably 80% or more, and the upper limit is 100%.

The elastic modulus of the first contraction of the adhesive material is preferably 0.1MPa or more, more preferably 0.2MPa or more, most preferably 0.5MPa, and preferably 10MPa or less, more preferably 5.0MPa or less, most preferably 5.0MPa or less. Preferably, it is below 3.0MPa.

When the adhesive material is stretched until the tensile stress reaches 50kPa, in the shrinkage test to release the tensile stress, the elongation (first stretch) when the tensile stress is 50kPa is preferably 10% or more, more preferably It is more than 100%, more preferably more than 250%, and most preferably more than 500%. When the elongation is 10% or more, deformation of the film during bending can be absorbed. The upper limit of the elongation is not particularly limited, but is usually about 1000%. The elongation is calculated by the following formula.

λ=(l ₁ -l ₀ )/l ₀ ×100% [λ: elongation, l ₀ : length before elongation (mm), l ₁ : length after elongation (mm)]

From the viewpoint of durability and adhesive strength, the gel fraction of the adhesive material is preferably 20% to 100%, more preferably 50% to 100%, and most preferably 70% to 100%. When the gel fraction is too low, insufficient cohesion may easily lead to insufficient durability. The gel fraction can be controlled by the blending amount of the cross-linking agent in the adhesive composition, the cross-linking treatment temperature, and the cross-linking treatment time.

(adhesive composition)

The adhesive material is a cured product of an adhesive composition containing a (meth)acrylic copolymer having a reactive functional group and a cross-linking agent. The adhesive composition contains: (A) a (meth)acrylic copolymer with reactive functional groups; and (B) a cross-linking agent.

((A) (Meth)acrylic copolymer having reactive functional groups)

The (A) (meth)acrylic copolymer with reactive functional groups (hereinafter referred to as "(A) copolymer") is obtained through living radical polymerization, and its molecular weight distribution (Mw/Mn) is less than 3.0, and a (meth)acrylic copolymer with reactive functional groups.

The (meth)acrylic copolymer only needs to be a copolymer whose main component (50% by mass or more) is a structural unit derived from a (meth)acrylic acid monomer, and may contain other than (meth)acrylic acid monomers. of structural units derived from vinyl monomers. The content rate of structural units derived from (meth)acrylic acid monomers in the copolymer (A) is preferably 80 mass% or more, more preferably 90 mass% in 100 mass% of the entire copolymer. above. In addition, the copolymer (A) may be composed only of structural units derived from (meth)acrylic acid monomers.

The copolymer (A) is preferably a (meth)acrylate copolymer. As long as the (meth)acrylate copolymer contains structural units derived from (meth)acrylate as the main component (50% by mass or more) The above) copolymer is sufficient, and may contain structural units derived from vinyl monomers other than (meth)acrylate. The (meth)acrylate is an ester compound produced from a compound having (meth)acrylic acid and a hydroxyl group. The content rate of structural units derived from (meth)acrylate in the copolymer (A) is preferably 80 mass% or more, more preferably 90 mass% or more, based on 100 mass% of the entire copolymer. .

The (A) copolymer system has reactive functional groups. The reactive functional group refers to a functional group capable of reacting with the functional group of the cross-linking agent (B) described below. Examples of the reactive functional group include one or more types selected from the group consisting of a hydroxyl group, a carboxyl group and an epoxy group, and preferably a hydroxyl group and/or a carboxyl group.

The amount of reactive functional groups per 100g of the (A) copolymer is preferably 0.5mmol/100g or more, more preferably 5mmol/100g or more, still more preferably 10mmol/100g or more, most preferably 15mmol/100g or more , and preferably 150mmol/100g or less, more preferably 100mmol/100g or less, still more preferably 70mmol/100g or less, most preferably 50mmol/100g or less. When the amount of the reactive functional group is 0.5 mmol/100g or more, the adhesive material has excellent durability, and when it is 150 mmol/100g or less, the adhesive material has excellent adhesion to the adhered object.

When the (A) copolymer has a carboxyl group, the amount of the carboxyl group per 100 g of the (A) copolymer is preferably 0.5 mmol/100g or more, preferably 5 mmol/100g or more, and more preferably 10 mmol/100g or more, The optimum is 15mmol/100g or more, more preferably 150mmol/100g or less, more preferably 100mmol/100g or less, still more preferably 70mmol/100g or less, and most preferably 50mmol/100g or less.

When the (A) copolymer has a hydroxyl group, the amount of hydroxyl groups per 100 g of the (A) copolymer is preferably 0.5 mmol/100g or more, preferably 5 mmol/100g or more, and more preferably 10 mmol/100g or more, The optimum is 15mmol/100g or more, more preferably 150mmol/100g or less, more preferably 100mmol/100g or less, still more preferably 70mmol/100g or less, and most preferably 50mmol/100g or less.

The copolymer (A) has reactive functional groups. That is, the copolymer (A) contains the structural unit (a-1) having a reactive functional group in its structure. The structural unit (a-1) having a reactive functional group may include only one type or two or more types. The reactive functional group may be included in any of the following: structural units derived from (meth)acrylic acid monomers (preferably (meth)acrylic acid ester monomers and/or (meth)acrylic acid), Structural units derived from vinyl monomers other than (meth)acrylic monomers. That is to say, the structural unit (a-1) with a reactive functional group is derived from a (meth)acrylic monomer (preferably a (meth)acrylate monomer and/or a reactive functional group). or (meth)acrylic acid) structural units, or structural units derived from vinyl monomers other than (meth)acrylic acid monomers having reactive functional groups.

The content rate of the structural unit (structural unit (a-1) having a reactive functional group) derived from the vinyl monomer having a reactive functional group) in the copolymer (A), based on 100 mass of the entire copolymer %, preferably 0.1 mass% or more, more preferably 0.5 mass% or more, still more preferably 1 mass% or more, most preferably 3 mass% or more, and preferably 20 mass% or less, more preferably 15 mass% % or less, more preferably 10 mass% or less, most preferably 8 mass% or less. When the content rate of the structural unit (a-1) is within the above range, an adhesive material having excellent balance between adhesion and durability to the object to be adhered can be obtained. Furthermore, the vinyl monomer system having a reactive functional group includes a (meth)acrylic acid monomer having a reactive functional group and a vinyl monomer other than the (meth)acrylic monomer having a reactive functional group.

Examples of the (meth)acrylic monomer include (b1) a (meth)acrylic monomer having no reactive functional group and (b2) a (meth)acrylic monomer having a reactive functional group. These monomers can be used alone or in combination of two or more. As said (b1) acrylic monomer which does not have a reactive functional group, (b1-1) the (meth)acrylate monomer which does not have a reactive functional group is preferable. As said (b2) tool Examples of (meth)acrylic acid monomers having reactive functional groups include (meth)acrylic acid ester monomers having (b2-1) reactive functional groups.

Examples of the (meth)acrylic monomer (b1) that does not have a reactive functional group include (meth)acrylate having a linear alkyl group and (meth)acrylate having a branched alkyl group. , (meth)acrylate with alkoxy group, (meth)acrylate with alkylene glycol structural unit, (meth)acrylate with alicyclic hydrocarbon group, (meth)acrylate with aromatic group (Meth)acrylates, (meth)acrylates with tertiary amino groups, (meth)acrylamides, etc. Among these, preferred ones are selected from the group consisting of (meth)acrylates having a linear alkyl group, (meth)acrylates having a branched alkyl group, (meth)acrylates having an alicyclic hydrocarbon group, and At least one of the group consisting of aromatic (meth)acrylates and (meth)acrylamides.

As the (meth)acrylate having a linear alkyl group, it is preferably a (meth)acrylate having a linear alkyl group with a carbon number of 1 to 20, and more preferably a (meth)acrylate having a carbon number of 1 to 20. Linear alkyl (meth)acrylate of 10. Examples of the (meth)acrylate having a linear alkyl group include: methyl methacrylate, ethyl methacrylate, n-propyl (meth)acrylate, n-butyl (meth)acrylate, n-hexyl (meth)acrylate, n-octyl (meth)acrylate, n-nonyl (meth)acrylate, n-decyl (meth)acrylate, n-lauryl (meth)acrylate, n-stearyl (meth)acrylate (meth)acrylic acid linear alkyl ester.

The (meth)acrylate having a branched alkyl group is preferably a (meth)acrylate having a branched alkyl group having a carbon number of 3 to 20, and more preferably a branched alkyl group having a carbon number of 3 to 20. Branched alkyl (meth)acrylate of 10. Examples of the (meth)acrylate having a branched alkyl group include isopropyl (meth)acrylate, isobutyl (meth)acrylate, sec-butyl (meth)acrylate, and (meth)acrylic acid. uncle (Meth)acrylic branched chain of butyl ester, isooctyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, isononyl (meth)acrylate, isodecyl (meth)acrylate, etc. Alkyl ester.

Examples of the (meth)acrylate having an alkoxy group include (meth)acrylic acid alkoxyalkyl groups such as methoxyethyl (meth)acrylate and ethoxyethyl (meth)acrylate. ester.

As the (meth)acrylate having a polyalkylene glycol structural unit, examples include: polyethylene glycol (polymerization degree = 2 to 10) methyl ether (meth)acrylate, polyethylene glycol ( Polyethylene glycol (degree of polymerization = 2 to 10) ethyl ether (meth) acrylate, polyethylene glycol (degree of polymerization = 2 to 10) propyl ether (meth) acrylate, polyethylene glycol (degree of polymerization = 2 to 10) phenylene ether (Meth)acrylates and other (meth)acrylates with polyethylene glycol structural units; such as polypropylene glycol (degree of polymerization=2~10) methyl ether (meth)acrylate, polypropylene glycol (degree of polymerization=2 ~10) Ethyl ether (meth)acrylate, polypropylene glycol (degree of polymerization = 2~10) propyl ether (meth)acrylate, polypropylene glycol (degree of polymerization = 2~10) phenylene ether (meth)acrylate, etc. (Meth)acrylate with polypropylene glycol structural unit, etc.

Examples of the (meth)acrylate having an alicyclic hydrocarbon group include (meth)acrylate having a cyclic alkyl group and (meth)acrylate having a polycyclic structure. As the (meth)acrylate having a cyclic alkyl group, a (meth)acrylate having a cyclic alkyl group having 6 to 12 carbon atoms is preferred. Examples of the cyclic alkyl group include a cyclic alkyl group having a monocyclic structure (for example, a cycloalkyl group), and may also have a chain portion. Specific examples of (meth)acrylate having a cyclic alkyl group with a monocyclic structure include: (meth)acrylic acid cyclohexyl, (meth)acrylic acid methylcyclohexyl, (meth)acrylic acid Cyclic alkyl (meth)acrylate such as cyclododecyl ester.

As the (meth)acrylate having a polycyclic structure, a (meth)acrylate having a polycyclic structure having 6 to 12 carbon atoms is preferred. Examples of the polycyclic structure include a cyclic alkyl group having a cross-linked ring structure (for example, adamantyl, norbornyl, isobornyl), and may also have a chain portion. Specific examples of the (meth)acrylate having a polycyclic structure include: (meth)bornyl acrylate, (meth)isobornyl acrylate, (meth)acrylic acid 1-adamantyl ester, (meth)acrylic acid ester, ) 2-adamantyl acrylate, 2-methyl-2-adamantyl (meth)acrylate, 2-ethyl-2-adamantyl (meth)acrylate, norbornyl (meth)acrylate , dicyclopentyl (meth)acrylate, dicyclopentyl (meth)acrylate, dicyclopentyloxyethyl (meth)acrylate, dicyclopentyloxyethyl (meth)acrylate, etc.

As the (meth)acrylate having an aromatic group, a (meth)acrylate having an aromatic group having 6 to 12 carbon atoms is preferred. Examples of the aromatic group include aryl groups and the like, and may also have chain portions such as alkylaryl groups, aralkyl groups, aryloxyalkyl groups, and the like. Examples of the (meth)acrylate having an aromatic group include compounds in which an aryl group is directly bonded to a (meth)acryloxy group, and compounds in which an aralkyl group is directly bonded to a (meth)acryloxy group. Compounds in which an alkylaryl group is directly bonded to a (meth)acryloxy group. The number of carbon atoms of the aryl group is preferably 6 to 12. The number of carbon atoms of the aralkyl group is preferably 6 to 12. The number of carbon atoms of the alkylaryl group is preferably 6 to 12. Examples of the (meth)acrylate having an aromatic group include benzyl (meth)acrylate, phenyl (meth)acrylate, phenoxyethyl (meth)acrylate, and the like.

Examples of the (meth)acrylate having a tertiary amino group include 2-(dimethylamino)ethyl (meth)acrylate, N,N-dimethylaminopropyl (meth)acrylate, etc. .

Examples of the (meth)acrylamides include N,N-dimethyl(meth)acrylamide, N,N-diethyl(meth)acrylamide, and N,N-dimethylacrylamide. Isopropyl(meth)acrylamide, (meth)acrylamide, N-methyl(meth)acrylamide, N-ethyl(meth)acrylamide, N-isopropyl(meth)acrylamide acrylamide, N-tert-butyl(meth)acrylamide, N-octyl(meth)acrylamide, N-methoxymethyl(meth)acrylamide, N-ethoxy Methyl(meth)acrylamide, N-propoxymethyl(meth)acrylamide, N-butoxymethyl(meth)acrylamide, diacetoneacrylamide, N-( Methyl acryloyl morpholine, etc. described Although (meth)acrylamides are (meth)acrylic acid monomers, they are not included in (meth)acrylic acid ester monomers.

Examples of (b2) the (meth)acrylic monomer having a reactive functional group include a (meth)acrylic monomer having a hydroxyl group (preferably a (meth)acrylic acid ester monomer), a (meth)acrylic acid monomer having a carboxyl group (Meth)acrylic acid monomer (preferably (meth)acrylic acid), (meth)acrylic acid monomer having an epoxy group (preferably (meth)acrylic acid ester monomer), etc. Among these, a (meth)acrylic acid monomer having a hydroxyl group and/or a (meth)acrylic acid monomer having a carboxyl group is preferred.

Examples of the (meth)acrylic monomer having a hydroxyl group include: 2-hydroxyethyl (meth)acrylate, 3-hydroxypropyl (meth)acrylate, and 2-hydroxypropyl (meth)acrylate. , 4-hydroxybutyl (meth)acrylate, 6-hydroxyhexyl (meth)acrylate, 8-hydroxyoctyl (meth)acrylate, 10-hydroxydecyl (meth)acrylate, (meth)acrylic acid Hydroxyalkyl (meth)acrylate such as 12-hydroxylauryl ester; hydroxyalkylcycloalkane (meth)acrylate such as (4-hydroxymethylcyclohexyl) methyl (meth)acrylate; hydroxyl Caprolactone adducts of alkyl (meth)acrylates, etc. Among these, hydroxyalkyl (meth)acrylate is preferred, and (meth)acrylate having a hydroxyalkyl group having 1 to 5 carbon atoms is more preferred.

Examples of the (meth)acrylic monomer having a carboxyl group include acid anhydrides such as maleic anhydride, succinic anhydride, and phthalic anhydride, and (meth)acrylate having a hydroxyl group (such as (methyl) Carboxyethyl acrylate, carboxypentyl (meth)acrylate, 2-(meth)acryloxyethylsuccinate, 2-(meth)acryloxyethylmaleate, 2-(meth)acryloxyethylmaleate Monomers obtained by the reaction of meth)acryloxyethyl phthalate), (meth)acrylic acid, etc. Among these, (meth)acrylic acid is preferred.

Examples of the (meth)acrylate having an epoxy group include glycidyl (meth)acrylate, 3,4-epoxycyclohexyl (meth)acrylic acid methyl ester, and the like.

Examples of vinyl monomers other than the (meth)acrylic monomer include: (b3) vinyl monomers other than (meth)acrylic monomers that do not have a reactive functional group; (b4) vinyl monomers that have reactivity Vinyl monomers other than functional (meth)acrylic monomers. These monomers can be used individually or in combination of 2 or more types.

Examples of the vinyl monomer other than the (meth)acrylic monomer having no reactive functional group in (b3) include aromatic vinyl monomers, heterocyclic-containing vinyl monomers, and vinyl carboxylates. , Vinyl monomers containing tertiary groups, vinyl monomers containing quaternary ammonium bases, vinylamides, α-olefins, dienes, vinyl halide monomers, etc.

Examples of the aromatic vinyl monomer include styrene, α-methylstyrene, 4-methylstyrene, 2-methylstyrene, 3-methylstyrene, and 4-methoxybenzene. Ethylene, 2-hydroxymethylstyrene, 1-vinylnaphthalene, etc.

Examples of the heterocyclic-containing vinyl monomer include 2-vinylthiophene, N-methyl-2-vinylpyrrole, 2-vinylpyridine, 4-vinylpyridine, and the like.

Examples of the vinyl carboxylate include vinyl acetate, vinyl pivalate, vinyl benzoate, and the like.

Examples of the vinyl monomer containing a tertiary amino group include N,N-dimethylallylamine.

Examples of the vinyl monomer containing a quaternary ammonium base include N-methacrylamideethyl-N,N,N-dimethylbenzylammonium chloride and the like.

Examples of the vinylamides include N-vinylformamide, N-vinylacetamide, 1-vinyl-2-pyrrolidone, N-vinyl-ε-lactam and the like.

Examples of the α-olefin include 1-hexene, 1-octene, 1-decene, and the like.

Examples of the dienes include butadiene, isoprene, 4-methyl-1,4-hexadiene, 7-methyl-1,6-octadiene, and the like.

Examples of the vinyl halide monomer include vinyl fluoride, vinylidene fluoride, trifluoroethylene, chlorotrifluoroethylene, tetrafluoroethylene, hexafluoropropylene, tetrafluoropropylene, vinylidene chloride, vinyl chloride, 1-Chloro-1-fluoroethylene, 1,2-dichloro-1,2-difluoroethylene, etc.

Examples of the vinyl monomer other than the (meth)acrylic monomer having a reactive functional group (b4) include a hydroxyl group-containing vinyl monomer, a carboxyl group-containing vinyl monomer, and an epoxy group-containing vinyl monomer. Vinyl monomer, etc.

Examples of the hydroxyl-containing vinyl monomer include p-hydroxystyrene, allyl alcohol, and the like.

Examples of the carboxyl group-containing vinyl monomer include crotonic acid, maleic acid, itaconic acid, citraconic acid, cinnamic acid, and the like.

Examples of the epoxy group-containing vinyl monomer include 2-allylxylan, glycidyl vinyl ether, 3,4-epoxycyclohexyl vinyl ether, and the like.

The copolymer (A) can be any one of a random copolymer, a block copolymer, and a graft copolymer, and is preferably a random copolymer.

The weight average molecular weight (Mw) of the copolymer (A) is preferably 200,000 or more, more preferably 300,000 or more, most preferably 400,000 or more, and preferably 2 million or less, more preferably 1.8 million or less, The best is less than 1.5 million, and the best is less than 1 million. When the Mw of the copolymer (A) is 200,000 or more, the cohesion force is improved and the heat resistance of the adhesive material is improved. When the Mw is 2,000,000 or less, the coating processability of the adhesive composition becomes better. The method for measuring the weight average molecular weight (Mw) will be described later.

The molecular weight distribution (PDI) of the (A) copolymer is less than 3.0, preferably less than 3.0, more preferably less than 2.5, still more preferably less than 2.2, most preferably less than 1.8. The smaller the PDI, the narrower the width of the molecular weight distribution, forming a copolymer with uniform molecular weight. When its value is 1.0, the width of the molecular weight distribution is the narrowest. When the PDI is below 3.0, the adhesive material that can be obtained has a small molecular weight or a low content of large molecular weight compared with the molecular weight of the designed polymer, and has excellent bending resistance. In addition, in the present invention, the molecular weight distribution (PDI) is a value calculated based on (weight average molecular weight (Mw)/(number average molecular weight (Mn)). The measurement methods of Mw and Mn will be described later.

The glass transition temperature (Tg) of the (A) copolymer is preferably -70°C or higher, more preferably -60°C or higher, and preferably is 0°C or lower, more preferably -10°C or lower, and most preferably - Below 20℃. When the glass transition temperature is above -70°C, sufficient cohesion is given to the adhesive material and the durability of the adhesive material is improved. When it is below 0°C, the adhesion of the adhesive material to the adhered object is improved and peeling is inhibited. , and the durability is improved.

The glass transition temperature (Tg) of the copolymer (A) is a value calculated from the following FOX formula (mathematical formula (1)). In the mathematical formula (1), Tg represents the glass transition temperature (°C) of the co-material. The Tgi system represents the glass transition temperature (°C) when the vinyl monomer forms a homopolymer. Wi represents the mass ratio of vinyl monomer i among all vinyl monomers forming the copolymer, ΣWi=1, and i is a natural number from 1 to n.

Table 1 shows the glass transition temperatures of typical homopolymers.

[Table 1]

The copolymer (A) is produced by radically polymerizing vinyl monomers through living radical polymerization. The living radical polymerization method maintains the simplicity and versatility of previous radical polymerization methods, and it grows without being hindered by side reactions that inactivate the growth terminals, such as termination reactions and chain transfers. It is easy to precisely control the molecular weight distribution and to produce polymers with uniform composition. Therefore, in the copolymer produced by living radical polymerization, the reactive functional groups are evenly distributed in each molecular chain. Therefore, when using a copolymer produced by living radical polymerization, the density of cross-linking points in the adhesive material becomes uniform overall.

In the living radical polymerization method, a random copolymer can be obtained by using a mixture of individual monomers (vinyl monomers) constituting the copolymer (A). In addition, the block copolymer is obtained by sequentially reacting the vinyl monomers constituting the copolymer.

Among the living radical polymerization methods, depending on the method of stabilizing the polymerization growth terminal, there are: a method using a transition metal catalyst (atom-transfer radical-polymerization, ATRP method); a method using a sulfur-based polymerization method; Methods using reversible chain transfer agents (reversible addition-fragmentation chain transfer polymerization, RAFT method); methods using radical tellurium compounds (organotellurium-mediated active free radical polymerization) Legal, Organotellurium mediated Living Radical Polymerization, TERP method) and other methods. Among these methods, the TERP method is preferable from the viewpoint of diversity of types of monomers that can be used, molecular weight control in the polymer range, uniform composition, or coloring.

The TERP method refers to a method of polymerizing a radically polymerizable compound (vinyl monomer) using an organic tellurium compound as a chain transfer agent, and is described in, for example, International Publication No. 2004/14848, International Publication No. 2004/14962, Methods of International Publication No. 2004/072126 and International Publication No. 2004/096870.

Specific polymerization methods of the TERP method include the following (a) to (d).

(a) A method of polymerizing a vinyl monomer with an organic tellurium compound represented by formula (1).

(b) A method of polymerizing a vinyl monomer using a mixture of an organic tellurium compound represented by formula (1) and an azo polymerization initiator.

(c) A method of polymerizing a vinyl monomer with a mixture of an organic tellurium compound represented by formula (1) and an organic ditellurium compound represented by formula (2).

(d) A method of polymerizing a vinyl monomer with a mixture of an organic tellurium compound represented by formula (1), an azo polymerization initiator, and an organic ditellurium compound represented by formula (2).

[In formula (1), R ¹ is an alkyl group, an aryl group or an aromatic heterocyclic group having 1 to 8 carbon atoms. R ² and R ³ are each independently a hydrogen atom or an alkyl group with 1 to 8 carbon atoms. R ⁴ is an alkyl group with 1 to 8 carbon atoms, an aryl group, a substituted aryl group, an aromatic heterocyclic group, an alkoxy group, a acyl group, an amide group, an oxycarbonyl group, a cyano group, an allyl group, or Propargyl.

In formula (2), R ¹ is an alkyl group, an aryl group or an aromatic heterocyclic group having 1 to 8 carbon atoms. ]

Specific examples of the organic tellurium compound represented by formula (1) include: ethyl-2-methyl-2-n-butyl tert-propionic acid propionate, ethyl-2-n-butyl tert-butyl propionate, (2-Hydroxyethyl)-2-methyl-methyl tert-butyl-propionate, etc., are described in International Publication No. 2004/14848, International Publication No. 2004/14962, International Publication No. 2004/072126, and Organotellurium compounds, etc. in International Publication No. 2004/096870. Examples of the organic ditellurium compound represented by formula (2) include dimethyl ditellurium, dibutyl ditellurium, and the like. The azo polymerization initiator can be used without particular limitation as long as it is an azo polymerization initiator commonly used in radical polymerization. Examples thereof include: 2,2'-azo(isobutyronitrile) (AIBN) ), 2,2'-Azobis(2,4-dimethylvaleronitrile)(ADVN), 1,1'-Azobis(1-cyclohexanecarbonitrile)(ACHN), 2,2' -Azobis(4-methoxy-2,4-dimethylvaleronitrile) (V-70), etc.

The polymerization step is to mix the vinyl monomer and the organic tellurium compound of formula (1) in a container replaced with an inert gas, and further perform the steps according to the type of the vinyl monomer for the purpose of promoting the reaction, controlling the molecular weight and molecular weight distribution, etc. Mix an azo polymerization initiator and/or an organic ditellurium compound of formula (2). At this time, examples of the inert gas include nitrogen gas, argon gas, helium gas, and the like. Preferred are argon gas and nitrogen gas. The usage amount of the vinyl monomer in (a), (b), (c) and (d) can be appropriately adjusted according to the physical properties of the target copolymer.

The polymerization reaction can be carried out without a solvent, but it can also be carried out using an aprotic solvent or a protic solvent commonly used in free radical polymerization, and stirring the mixture. OK. Examples of usable aprotic solvents include anisole, benzene, toluene, propylene glycol monomethyl ether acetate, ethyl acetate, tetrahydrofuran (THF), and the like. Examples of the protic solvent include water, methanol, 1-methoxy-2-propanol, and the like. The solvent can be used alone or in combination of two or more. The usage amount of the solvent can be adjusted appropriately, for example, it is preferably 0.01 ml to 50 ml per 1 g of vinyl monomer. The reaction temperature and reaction time can be appropriately adjusted according to the molecular weight or molecular weight distribution of the polymer obtained, but usually stirring at 0°C to 150°C for 1 minute to 100 hours. After the polymerization reaction is completed, the target copolymer can be isolated by using general separation and purification methods, such as removing the used solvent and residual vinyl monomer from the obtained reaction mixture.

The growing end of the copolymer obtained through the polymerization reaction is in the form of -TeR ¹ (where R ¹ is the same as above) derived from the tellurium compound, and is deactivated by operation in the air after the polymerization reaction. , but tellurium atoms may remain. Since the polymer with tellurium atoms remaining at the end may be colored or have poor thermal stability, it is preferable to remove the tellurium atoms. Examples of methods for removing tellurium atoms include radical reduction, adsorption with activated carbon, etc., adsorption of metals with ion exchange resin, etc. In addition, a combination of these methods can also be used. In addition, the other end of the copolymer obtained by the polymerization reaction (the end opposite to the growth end) is -CR ² R ³ R ⁴ derived from the tellurium compound (where R ² , R ³ and R ⁴ are the same as the formula) R ² , R ³ and R ⁴ in (1) are the same) type.

((B) Cross-linking agent)

The adhesive composition contains (B) a cross-linking agent. The cross-linking agent (B) is a compound having two or more reactive groups in one molecule that can react with the reactive functional group of the copolymer (A). The (B) cross-linking agent is not particularly limited, and examples thereof include isocyanate-based cross-linking agents, epoxy-based cross-linking agents, aziridine-based cross-linking agents, metal chelate-type cross-linking agents, and melamine resin-based cross-linking agents. Cross-linking agent, urea resin system Combined agents, etc. Among these, isocyanate-based cross-linking agents, epoxy-based cross-linking agents, and aziridine-based cross-linking agents are preferred, and from the viewpoint of easy control of the progress of the cross-linking reaction and bending resistance, more preferred are Isocyanate cross-linking agent or epoxy cross-linking agent.

(Isocyanate cross-linking agent)

The isocyanate cross-linking agent is a compound having two or more isocyanate groups (including an isocyanate regeneration type functional group that temporarily protects the isocyanate group through a blocking agent, oligomerization, etc.) as a reactive group in one molecule. The isocyanate cross-linking agent may be used alone or in combination of two or more.

Examples of isocyanate-based crosslinking agents include aromatic polyisocyanates, alicyclic polyisocyanates, aliphatic polyisocyanates, and adducts of these with various polyols, through isocyanurate bonds, and biuret bonds. , allophanate bonds, etc. and polyfunctionalized polyisocyanates, etc. More specifically, for example, one or more types selected from the following can be used: lower aliphatic polyisocyanates such as butylene diisocyanate and hexamethylene diisocyanate; such as cyclopentadiisocyanate and cyclohexane diisocyanate. Alicyclic polyisocyanates such as isocyanate, isophorone diisocyanate, hydrogenated toluene diisocyanate, 1,3-bis(isocyanatomethyl)cyclohexane, etc.; such as 2,4-toluene diisocyanate, 2, 6-Toluene diisocyanate, 4,4'-diphenylmethane diisocyanate, 1,3-xylylene diisocyanate, 1,4-xylylene diisocyanate, tetramethylxylene diisocyanate, 1 , Aromatic polyisocyanates such as 5-naphthalene diisocyanate, triphenylmethane triisocyanate, polymethylene polyphenyl isocyanate; such as trimethylolpropane/toluene diisocyanate trimer adduct, trimethylol Trimethylpropane/hexamethylene diisocyanate trimer adduct, isocyanate adducts such as the isocyanurate form of hexamethylene diisocyanate; trimethylolpropane adduct of xylene diisocyanate; Trimethylolpropane adduct of hexamethylene diisocyanate; polyether polyisocyanate, polyester polyisocyanate, and their adducts with various polyols, through isocyanurate bonds, dicondensation Polyisocyanate polyfunctionalized with urea bonds, allophanate bonds, etc. Among these, an aliphatic polyisocyanate is preferably used, and an isocyanurate form of an aliphatic diisocyanate (for example, an isocyanurate form of hexamethylene diisocyanate) is more preferred.

(Epoxy cross-linking agent)

The epoxy cross-linking agent is a compound having two or more epoxy groups as reactive groups in one molecule. The epoxy cross-linking agent can be used alone or in combination of two or more.

Examples of the epoxy cross-linking agent include bisphenol A, epichlorohydrin type epoxy resin, vinyl glycidyl ether, N,N,N',N'-tetraglycidyl-m-xylene Diamine, diglycidyl aniline, diamine glycidylamine, 1,3-bis(N,N-diglycidylaminomethyl)cyclohexane, 1,6-hexanediol diglycidyl ether, new Pentylene glycol diglycidyl ether, ethylene glycol diglycidyl ether, propylene glycol diglycidyl ether, polyethylene glycol diglycidyl ether, polypropylene glycol diglycidyl ether, sorbitol polyglycidyl ether, glycerin polyglycidyl ether , Pentaerythritol polyglycidyl ether, glycerol diglycidyl ether, glyceryl triglycidyl ether, polyglycerol polyglycidyl ether, sorbitan polyglycidyl ether, trimethylolpropane polyglycidyl ether, adipic acid diglycidyl ether Ester, diglycidyl phthalate, triglycidyl tris(2-hydroxyethyl)isocyanate, resorcinol diglycidyl ether, bisphenol-S-diglycidyl ether, etc.

(aziridine cross-linking agent)

The aziridine-based cross-linking agent is a compound having two or more aziridinyl groups as reactive groups in one molecule. The aziridine cross-linking agent can be used alone or in combination of two or more.

Examples of aziridine-based cross-linking agents include: tris-2,4,6-(1-azido)-1,3,5-triazine, tris[1-(2-methyl)-azide base]phosphine oxide, hexa[1-(2-methyl)-azido]triphosphorus triazine, etc.

The content of the reactive group of the cross-linking agent (B) is preferably 0.5 mmol/g or more, more preferably 1.0 mmol/g or more, still more preferably 3.0 mmol/g or more, most preferably 6.0 mmol/g or more, And it is preferably 20 mmol/g or less, more preferably 15.0 mmol/g or less, most preferably 12.0 mmol/g or less. When the content of the reactive group of the cross-linking agent (B) is within this range, the cohesive force of the adhesive material is better, and even if it is bent, deformation at the bend can be further suppressed.

The content of the cross-linking agent (B) in the adhesive composition is preferably 0.01 part by mass or more, more preferably 0.03 part by mass or more, and more preferably 1 part by mass based on 100 parts by mass of the copolymer (A). or less, more preferably 0.5 parts by mass or less. When the content of the cross-linking agent (B) is 0.01 parts by mass or more, sufficient cohesive force is exerted and excellent flexibility is exhibited. When the amount is 1 part by mass or less, sufficient adhesion to the base material is exerted, and floating and peeling during bending can be suppressed.

In the adhesive composition, the molar ratio of the reactive functional groups of the copolymer (A) relative to the reactive groups of the cross-linking agent (B) (molar amount of the reactive functional groups/reactive groups The molar amount) is preferably 1 or more, more preferably 2 or more, most preferably 10 or more, and preferably 1,000 or less, more preferably 200 or less, most preferably 100 or less.

(Other additives)

In the adhesive composition, in addition to the (A) copolymer and (B) cross-linking agent, other additives may be mixed and used. Examples of other additives include cross-linking accelerators, cross-linking retarders, tackifying resins (tackifying agents), plasticizers, softeners, release aids, silane coupling agents, dyes, pigments, pigments, fluorescent Optical brightener, antistatic agent, wetting agent, surfactant, tackifier, antifungal agent, preservative, oxygen absorption Agents, UV absorbers, antioxidants, near-infrared absorbers, water-soluble matting agents, fragrances, metal deactivators, nucleating agents, alkylating agents, flame retardants, lubricants, processing aids, etc. These adhesive materials can be appropriately selected and blended according to their uses and purposes.

(cross-linking accelerator)

A crosslinking accelerator may be incorporated into the adhesive composition as necessary. Examples of crosslinking accelerators include organotin compounds, metal chelates, and the like. The cross-linking accelerator can be used alone or in combination of two or more.

Examples of the organotin compound include dibutyltin dilaurate, dioctyltin laurate, dibutyltin dioctoate, and the like. The metal chelate refers to a complex in which ligands with two or more coordination atoms form a ring and are bonded to the central metal.

The content of the cross-linking accelerator in the adhesive composition is preferably 0.01 parts by mass or more, more preferably 0.02 parts by mass or more, and most preferably 0.04 parts by mass or more based on 100 parts by mass of the copolymer (A). , and it is preferably 0.5 parts by mass or less, more preferably 0.4 parts by mass or less, and most preferably 0.3 parts by mass or less. By setting the content of the crosslinking accelerator within the above range, excellent crosslinking accelerating effect can be obtained.

(Cross-linking blocker)

A cross-linking retardant may be incorporated into the adhesive composition as necessary. The cross-linking retardant refers to a compound in an adhesive composition containing a cross-linking agent that can inhibit an excessive increase in the viscosity of the adhesive composition by blocking the functional groups containing the cross-linking agent. The type of cross-linking retardant is not particularly limited. For example, acetylacetone, hexane-2,4-dione, heptane-2,4-dione, and octane-2,4-dione can be used. β-diketones such as acetyl methyl acetate, acetyl ethyl acetate, acetyl propyl acetate, acetyl butyl acetate, acetyl acetate β-keto esters such as octyl acetate, oleyl acetate, lauryl acetate, stearyl acetate, etc.; benzoyl acetone, etc. The cross-linking retardant is preferably one that functions as a chelating agent, and among these, β-diketones and β-ketoesters are preferred.

The content of the cross-linking retardant that can be incorporated into the adhesive composition is preferably 0.1 parts by mass or more, more preferably 0.2 parts by mass or more, and most preferably 0.5, based on 100 parts by mass of the (A) copolymer. Parts by mass or less, preferably 4.0 parts by mass or less, more preferably 3.0 parts by mass or less, most preferably 1.5 parts by mass or less. By adjusting the content of the cross-linking retardant to the above range, after the (B) cross-linking agent is incorporated into the adhesive composition, excessive increase in viscosity and gelation of the adhesive composition can be suppressed. , and can extend the storage stability (usable period) of the adhesive composition.

(silane coupling agent)

In the adhesive composition, a silane coupling agent can be blended and used as needed. The silane coupling agent is not particularly limited, and examples thereof include: 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropyltriethoxysilane, 3-glycidoxypropyltriethoxysilane, Silane coupling agents containing epoxy groups such as oxypropylmethyldiethoxysilane, 2-(3,4 epoxycyclohexyl)ethyltrimethoxysilane, etc.; such as 3-aminopropyltrimethoxy Silane, N-2-(aminoethyl)-3-aminopropylmethyldimethoxysilane, 3-triethoxysilyl-N-(1,3-dimethylbutylene)propylamine, Silane coupling agents containing amino groups such as N-phenyl-γ-aminopropyltrimethoxysilane; such as 3-acryloxypropyltrimethoxysilane, 3-methacryloxypropyltriethyl Silane coupling agents containing (meth)acrylic acid groups, such as oxysilane; silane coupling agents containing isocyanate groups, such as 3-isocyanatepropyltriethoxysilane, etc.

The content of the silane coupling agent that can be incorporated into the adhesive composition is preferably less than 1 part by mass, more preferably 0.01 to 1 part by mass, based on 100 parts by mass of the (A) copolymer. for 0.02 parts by mass ~ 0.6 parts by mass. By adjusting the content of the silane coupling agent within the above range, the water resistance at the interface when the adhesive material is applied to hydrophilic adherends such as glass can be improved.

(Adhesive agent)

In the adhesive composition, a tackifier other than the copolymer used (A) may be incorporated as necessary. The tackifier is not particularly limited, and examples thereof include rosin-based tackifier resins, terpene-based tackifier resins, phenol-based tackifier resins, hydrocarbon-based tackifier resins, and the like.

Examples of rosin-based viscosity-imparting resins include unmodified rosin (raw rosin) such as colloidal rosin, woody rosin, and oily rosin, and modified rosin modified by polymerization, disproportionation, hydrogenation, etc. Sexual rosin (such as polymerized rosin, stabilized rosin, disproportionated rosin, fully hydrogenated rosin, partially hydrogenated rosin, other chemically modified rosin, etc.), and various rosin derivatives, etc.

Examples of the rosin derivatives include: rosin phenolic resins obtained by adding phenol to rosins (unmodified rosin, modified rosin) and thermally polymerizing them; such as passing unmodified rosin through alcohols. Esterified rosin ester compounds (unmodified rosin ester), modified rosin ester compounds obtained by esterifying modified rosin through alcohols (polymerized rosin ester, stabilized rosin ester, disproportionated rosin ester, fully hydrogenated rosin ester , partially hydrogenated rosin ester, etc.); rosin ester resins modified by unsaturated fatty acids through unsaturated fatty acids; rosin ester resins modified through unsaturated fatty acids; Unsaturated fatty acid modified rosin ester resin; rosin alcohol obtained by reducing the carboxyl groups in unmodified rosin, modified rosin, unsaturated fatty acid modified rosin resin or unsaturated fatty acid modified rosin ester resin Resins; metal salts of rosin-based resins (especially rosin ester-based resins) such as unmodified rosin and modified rosin.

Examples of the terpene-based tackifying resin include terpene-based resins such as α-pinene polymer, β-pinene polymer, dipentene polymer, etc. These terpene-based resins are modified (phenolic resins) modified, aromatic modification, hydrogenation modification, hydrocarbon modification, etc.) modified terpene resin (such as terpene phenol resin, styrene-modified terpene resin, aromatic modified terpene resin, Hydrogenated terpene resin).

Examples of the phenolic tackifying resin include condensates of various phenols (such as phenol, m-cresol, 3,5-xylenol, p-alkylphenol, resorcinol) and formaldehyde (such as alkylphenol). resin, xylene-based resin), resol phenolic resin (resol) obtained by the addition reaction of the phenols and formaldehyde through an alkali catalyst, and the condensation reaction of the phenols and formaldehyde through an acid catalyst of phenolic varnish, etc.

Examples of hydrocarbon-based tackifying resins (petroleum-based tackifying resins) include aliphatic hydrocarbon resins [such as olefins with 4 to 5 carbon atoms and dienes (such as butene-1, isobutene, pentene- Class 1 olefins; polymers of aliphatic hydrocarbons such as butadiene, 1,3-pentadiene, isoprene and other dienes), aliphatic cyclic hydrocarbon resins [converting so-called "C4 Alicyclic hydrocarbon resins and cyclic diene compounds (cyclopentadiene, dicyclopentadiene, acetylene norbornene) obtained by polymerizing the cyclized dimer of "petroleum fraction" or "C5 petroleum fraction" , dipentene, etc.) or their hydrogenation products, alicyclic hydrocarbon resins obtained by hydrogenating the aromatic rings of the following aromatic hydrocarbon resins or aliphatic/aromatic petroleum resins, etc.], aromatic hydrocarbon resins [carbon Vinyl-containing aromatics with 8 to 10 atoms (such as styrene, vinyltoluene, α-methylstyrene, indene, methylindene, etc.)], aliphatic/aromatic petroleum resin (styrene-olefin copolymer etc.), aliphatic/alicyclic petroleum resin, hydrogenated hydrocarbon resin, benzofuran resin, benzofuran-indene resin (coumarone-indene resin), etc.

The content of the tackifier that can be incorporated into the adhesive composition is preferably 5 parts by mass or more, more preferably 10 parts by mass or more, and most preferably 20 parts by mass relative to 100 parts by mass of the (A) copolymer. parts by mass or above, and preferably 60 parts by mass or less, more preferably 50 parts by mass or less, and most preferably 40 parts by mass or less. By adjusting the content of the adhesive agent within the above range, sufficient adhesion to the adhered object can be ensured, and floating and peeling during bending can be suppressed.

(Method for manufacturing adhesive composition)

The adhesive composition can be produced by incorporating the (A) copolymer, (B) cross-linking agent and other additives as needed. The adhesive composition may contain a solvent produced from the copolymer (A), and a suitable solvent may be further added to obtain a solution diluted to a viscosity suitable for forming an adhesive layer.

Examples of the solvent include: aliphatic hydrocarbons such as hexane, heptane, etc.; aromatic hydrocarbons such as toluene, xylene, etc.; halogenated hydrocarbons such as dichloromethane, ethyl chloride, etc.; such as acetone, methyl ethyl ketone, 2-pentane, etc. Ketones such as ketone, isophorone, cyclohexanone, etc.; esters such as ethyl acetate, butyl acetate, etc.; cellosolve solvents such as ethyl cellosolve, etc.; ethylene glycol such as propylene glycol monomethyl ether, etc. Alcohol ether solvent. These solvents may be used individually by 1 type, or in mixture of 2 or more types.

The amount of solvent used is not particularly limited and can be appropriately adjusted to a viscosity suitable for coating of the adhesive composition. However, from the viewpoint of coating properties, for example, 1 to 90 mass % is preferred, and 10 is more preferred. Mass %~80 mass %, optimally 20 mass %~70 mass %.

(Use of adhesive material)

The use of the adhesive material is not particularly limited and can be used in a wide range of applications. In particular, it is preferably used in flexible displays that can be bent repeatedly or as components used in flexible displays.

Examples of flexible displays that can be repeatedly bent and stretched include foldable displays, roll displays that can be rolled into a tube, and the like. Flexible displays are expected to be used in mobile terminals such as smartphones and tablets, and in stowable fixed displays.

[Adhesive sheet]

The adhesive sheet of the present invention is characterized by having: an adhesive layer for bonding one flexible member and another flexible member; and a flexible sheet member that is bonded to at least one of the adhesive layers. on the surface of the side, wherein the adhesive layer is formed of the adhesive material.

Examples of the structure of the adhesive sheet include an adhesive layer and a first flexible sheet member, wherein the first flexible sheet member is attached to one surface of the adhesive layer. on; and having an adhesive layer, a first flexible sheet member, and a second flexible sheet member, wherein the first flexible sheet member is attached to the surface of one side of the adhesive layer On the other side, the second flexible sheet member is attached to the surface of the other side of the adhesive layer.

FIG. 1 shows an example of the adhesive sheet of the present invention. The adhesive sheet 10 in FIG. 1 is composed of an adhesive layer 12, a first flexible sheet member 14, and a second flexible member 16 sandwiching the adhesive layer 12. The adhesive layer 12 is in contact with the release surfaces of the first flexible member 14 and the second flexible member 16 .

(adhesive layer)

The thickness of the adhesive layer is preferably 5 μm or more, more preferably 10 μm or more, still more preferably 15 μm or more, and most preferably 20 μm or more. When the thickness of the adhesive layer is 5 μm or more, sufficient adhesion to the flexible sheet member can be obtained. In addition, the thickness of the adhesive layer is preferably 100 μm or less, more preferably 75 μm or less, and most preferably 50 μm or less. When the thickness of the adhesive layer is 100 μm or less, protrusion of the adhesive layer can be suppressed.

The adhesive force of the adhesive layer to the flexible sheet member (excluding the peel-off sheet) at 23°C is preferably 10N/25mm or more, more preferably 15N/25mm or more, and most preferably 20N/25mm or more. When it is 10N/25mm or more, the floating or peeling of the adhesive material can be suppressed. The upper limit of the adhesive force is not particularly limited, but is usually 50N/25mm or less, preferably 40N/25mm or less.

(Flexible sheet member)

Examples of the flexible sheet member include a flexible base sheet, a release sheet, and the like. The base material sheet is a sheet member used to support the adhesive layer, and this sheet member may be a functional sheet member. Examples of the functional sheet member include cover films, barrier films, polarizing films, retardation films, optical compensation films, brightness enhancement films, diffusion films, anti-reflection films, and the like. The peeling sheet is used to protect the adhesive layer until the adhesive layer is adhered to the object to be adhered, and is peeled off from the adhesive layer before the adhesive layer is adhered to the object to be adhered.

Generally speaking, "sheet" is defined according to Japanese Industrial Standards (JIS) as a thin, flat product whose thickness is small relative to length and width. Generally speaking, "film" refers to a film whose thickness is extremely small compared to length and width. Thin flat products with an arbitrary thickness limit, generally supplied in the form of rolls (Japanese Industrial Standard JIS K6900). For example, in a narrow sense, a thickness of 100 μm or more is called a sheet, and a thickness of less than 100 μm is called a film. However, the boundary between a sheet and a film is not absolute, and there is no need to distinguish the two in words in the present invention. Therefore, in the present invention, even when it is called "sheet", it also includes "film", and when it is called "film", it also includes "film". "piece".

Examples of the flexible sheet member include polymer material sheets, glass sheets, and the like. The thickness of the flexible member is not particularly limited, but from the viewpoint of excellent operability, it is preferably 2 μm to 500 μm, and more preferably 2 μm to 200 μm.

Examples of the polymer material include: polyester resins such as polyethylene terephthalate resin and polyethylene naphthalate resin; polycarbonate resin; poly(meth)acrylate resin; Polystyrene resin; polyamide resin; polyimide resin; polyacrylonitrile resin; polyolefin resins such as polypropylene resin, polyethylene resin, polycyclic olefin resin, cyclic olefin copolymer resin, etc.; such as triacetyl Cellulose resins, diethyl cellulose resins, and other cellulose-based resins; polyphenylene sulfide resin; polyvinyl chloride resin; polyvinylidene chloride resin; polyvinyl alcohol resin, etc.

The flexible sheet member may be composed of a single layer formed of a layer containing one or more of the polymer materials. It may also be composed of two or more layers, such as a layer containing one or two or more types of polymer materials and a layer containing one or two or more types of polymer materials different from this layer.

The flexible sheet member is preferably a release sheet in which a release treatment is applied to a surface in contact with the adhesive layer. Examples of release agents used for release treatment include silicone-based, fluorine-based, alkyd-based, unsaturated polyester-based, polyolefin-based, wax-based release agents, and the like.

Preferably, the adhesive sheet has: a first flexible sheet member that is attached to the surface of one side of the adhesive layer; a second flexible sheet member that is attached to the adhesive layer. On the surface of the other side of the layer, the first flexible sheet member is a first release sheet, the second flexible sheet member is a second release sheet, and the first release sheet and the The second release sheet is bonded so that its respective release surfaces are in contact with the adhesive layer. In addition, when the adhesive layer is sandwiched between two release sheets, it is preferable that the release sheet on one side be a heavy release type release sheet with a large release force, and the release sheet on the other side be a release sheet with a small release force. Light peeling type peel-off sheet.

(Manufacturing of adhesive sheets)

The adhesive sheet can be manufactured by, for example, coating the above-mentioned adhesive composition on a flexible sheet member and curing it through drying and heating treatment as needed to form an adhesive layer.

For coating the adhesive composition, methods such as reverse gravure coating, direct gravure coating, die coating, rod coating, wire rod coating, roller coating, and spin coating can be used. , various coating methods such as dip coating, spray coating, knife coating, and kiss coating; or various printing methods such as inkjet printing, offset printing, screen printing, flexographic printing, etc. In addition, before coating the adhesive composition, surface treatment such as corona treatment, plasma treatment, hot air treatment, ozone treatment, ultraviolet treatment, etc. can also be applied to the surface of the release sheet.

The drying and curing steps are not particularly limited as long as the solvent used in the adhesive composition can be removed and cured, but it is preferably carried out at a temperature of 60°C to 150°C for about 20 seconds to 300 seconds. In particular, the preferred drying temperature is 100°C to 130°C.

When the first flexible sheet member is disposed on one side of the adhesive layer and the second flexible sheet member is disposed on the other side of the adhesive layer, the adhesive composition can be applied to the first flexible sheet member. The sheet member is used to form an adhesive layer on the first flexible sheet member, and then attach the second flexible sheet member to the adhesive layer. In addition, the adhesive layer can be further cured as needed. Examples of the curing conditions include, for example, about 3 to 7 days at 40°C.

[Flexible laminated member]

The flexible laminated member of the present invention is characterized by comprising: a first flexible member; a second flexible member; and an adhesive layer for connecting the first flexible member and the second flexible member. The flexible members are attached to each other, and the adhesive layer is formed of the adhesive material. Since the adhesive layer of the flexible laminated member is formed of the adhesive material, even if the flexible laminated member is bent repeatedly, it will remain in the bend. There is no floating or peeling at the interface between the adhesive layer and the flexible member, and appearance defects such as cracks and ripples are suppressed.

FIG. 2 shows an example of the flexible laminated member of the present invention. The flexible laminated component 20 of FIG. 2 has: a first flexible component 22; a second flexible component 24; and an adhesive layer 12 located between the first flexible component 22 and the second flexible component. between the components 24 and used to fit these flexible components.

Examples of the structure of the flexible laminated member include a structure in which both the first flexible member and the second flexible member are components of a flexible device; and the second flexible member is a flexible member. A flexible device is provided, and the first flexible member is a functional sheet member that is attached to the flexible device. Examples of the flexible device include a foldable display, a roll display cover film that can be rolled into a tube shape, and the like. Examples of the functional sheet member include cover films, barrier films, polarizing films, retardation films, optical compensation films, brightness enhancement films, diffusion films, anti-reflection films, transparent conductive films, metal mesh films, buffer films, and the like.

The first flexible member and the second flexible member are members that can be bent repeatedly. Examples of the first flexible member and the second flexible member include: flexible substrate materials, functional sheet members, display elements (organic electroluminescence (EL) modules, electronic paper modules) group) etc. Preferably, at least one of the first flexible member and the second flexible member is a display element.

(Method for manufacturing flexible laminated member)

The manufacturing method of the flexible laminated member of the present invention is not particularly limited, and examples thereof include the following methods (1) to (4).

(1) Peel off the peeling sheet adhered to one side of the adhesive sheet and attach the exposed adhesive layer to the first flexible member, and then attach it to the other side of the adhesive sheet. The peeling sheet is peeled off, and the exposed adhesive layer is bonded to the second flexible member to obtain a flexible laminated member.

(2) Coat the adhesive composition on one side of the first flexible member, and cure it by drying and heating as necessary to form an adhesive layer, and then remove the release sheet from the surface. Fit onto this adhesive layer. Then, the release sheet is peeled off and the exposed adhesive layer is bonded to the second flexible member to obtain a flexible laminated member.

(3) Coat the adhesive composition on one surface of the first flexible member, and cure it by drying and heating as needed to form an adhesive layer, and then attach the second flexible member to the surface of the first flexible member. This adhesive layer is used to obtain a flexible laminated component.

(4) Coat the adhesive composition on the releasable surface of the release sheet, cure it through drying and heat treatment as required to form an adhesive layer, and then attach the first flexible member to the adhesive layer. superior. Then, the release sheet is peeled off and the exposed adhesive layer is bonded to the second flexible member to obtain a flexible laminated member.

In addition, even in any case of (1) to (4) above, the order of using the first flexible member and the second flexible member may be replaced.

In the formation of the adhesive layer, the same various coating methods and various printing methods used in the manufacture of the adhesive layer can be used, and the same is true for the drying and curing steps. In addition, it can be cured as needed. In addition, as a release sheet used when manufacturing a flexible laminated member, the same release sheet used for a pressure-sensitive adhesive sheet can be used.

(Specific example of flexible laminated member)

The following describes a preferred aspect of the flexible laminated component of the present invention with reference to FIG. 3 . FIG. 3 is a schematic cross-sectional view of a specific example of the flexible laminated member of the present invention. The flexible laminated member 30 shown in FIG. 3 has: a first flexible member 32; a second flexible member 34; and an adhesive layer 12 located between the first flexible member 32 and the second flexible member 34. between the flexible members 34 and used to adhere the flexible members to each other. Moreover, the first flexible member 32 is a covering film, and the covering film has a covering film base material 32 a and a hard coating layer 32 b. The covering film base material 32 a is bonded to the adhesive layer 12 . In addition, the second flexible member 34 is a polarizing film.

The adhesive layer 12 can inhibit lifting and peeling at the interface between the first flexible member 32 and the second flexible member 34 at the bend. Therefore, it is also possible to suppress the occurrence of cracks in the hard coat layer 32b provided on the cover film (first flexible member 32) when the flexible laminated member 30 is repeatedly bent.

(covering film base material)

The cover film base material 32a is not particularly limited as long as it has flexibility and transparency. Examples of the cover film base material 32a include a transparent polymer film, a transparent glass film, and the like. Transparency refers to the total transmittance of more than 50% in the visible light wavelength range. The total light transmittance is preferably above 85%. The total light transmittance is measured according to JIS K7361-1 (1997).

The yellowness (YI value) of the cover film base material 32a is preferably 20 or less, more preferably 10 or less, and most preferably 5 or less. This makes it possible to obtain a display that displays images with high transparency and high color reproducibility. The yellowness (YI value) is measured in accordance with JIS 7373 (2006).

The thickness of the covering base material 32a is not particularly limited, but from the viewpoint of ease of operation, it is preferably 2 μm to 500 μm, and more preferably 2 μm to 200 μm.

Examples of the polymer material used as the polymer film of the cover film base material 32a include: polyester resin (such as polyethylene terephthalate resin, polyethylene naphthalate resin, etc.); polycarbonate Resin; poly(meth)acrylate resin; polystyrene resin; polyamide resin; polyimide resin; polyacrylonitrile resin; polyolefin resin (such as polypropylene resin, polyethylene resin, polycyclic olefin resin, Cyclic olefin copolymer resin, etc.); cellulose resin (such as triacetyl cellulose resin, diethyl cellulose resin); polyphenylene sulfide resin; polyvinyl chloride resin; polyvinylidene chloride resin; polyvinyl alcohol Resin etc.

The polymer material may be composed of only one type, or may be composed of a combination of two or more types. From the viewpoint of optical properties, durability, etc., preferably, the polymer material contains polyethylene terephthalate resin, polyimide resin, polycarbonate resin, poly(meth)acrylic acid At least one of the group consisting of ester resin, polycyclic olefin resin, cyclic olefin copolymer resin and triacetyl cellulose resin, particularly preferably contains polyimide resin. The film system containing polyimide resin has the flexibility to withstand repeated bending, and has excellent surface hardness and heat resistance. The content rate of the polyimide resin in the polymer material is preferably 50 mass% or more, more preferably 70 mass% or more, and most preferably 90 mass% or more. The polymer material may also be composed only of polyimide resin.

The cover film base material 32a may have a single-layer structure or a multi-layer structure of two or more layers. In addition, each layer of the cover film base material 32a may be composed of only one type of the above-mentioned polymer materials, or may be composed of two or more types of the above-mentioned polymer materials.

(hard coat)

The pencil hardness of the hard coat layer 32b is preferably 3H or more, more preferably 4H or more. The pencil hardness of the hard coating layer 32b refers to the pencil hardness of the surface of the hard coating layer 32b formed on one side surface of the cover film base material 32a, and does not form an adhesion on the other side surface of the cover film base material 32a. Measured in layer 12 condition. The pencil hardness of the hard coat layer 32b is measured in accordance with JIS K5600-5-4.

The thickness of the hard coat layer 32b is preferably 0.5 μm or more, more preferably 1.0 μm or more, most preferably 3.0 μm or more, and preferably 10.0 μm or less, more preferably 8.0 μm or less, most preferably 6.0 μm or less. When the thickness is 0.5 μm or more, the pencil hardness of the cover film 32 can be sufficiently ensured. When the thickness is 10.0 μm or less, the flexibility of the cover film to withstand repeated bending can be sufficiently ensured, and curling of the cover film 32 caused by the thermal shrinkage difference between the hard coat layer 32 b and the cover film base material 32 a can be suppressed. The thickness of the hard coat layer 32b is the thickness of the smooth portion, and when the hard coat layer contains particles, it refers to the thickness of the smooth portion of the portion without unevenness caused by particles in the thickness direction.

From the viewpoint of high hardness, high flexibility, productivity, etc., the hard coat layer 32b is preferably composed of a cured product of a curable composition containing an ultraviolet curable compound.

Examples of the ultraviolet curable compound include monomers, oligomers, prepolymers, and the like having an ultraviolet reactive reactive group. Examples of ultraviolet reactive reactive groups include radically polymerizable reactive groups having ethylenically unsaturated bonds such as (meth)acrylyl, allyl, vinyl, etc.; such as oxyheterocycles Cationic polymerization type reactive groups such as butyl group, etc. Among these, as the ultraviolet reactive reactive group, a (meth)acrylyl group and an oxetanyl group are more preferred, and a (meth)acrylyl group is more preferred.

Examples of the compound having a (meth)acryl group include urethane (meth)acrylate, silicone (meth)acrylate, alkyl (meth)acrylate, and aromatic (meth)acrylate. base ester wait. In particular, urethane (meth)acrylate is preferred from the viewpoint of being relatively soft and improving the flexibility of the hard coat film.

The urethane (meth)acrylate is obtained through the addition reaction of a polyol, an isocyanate compound and a (meth)acrylate having a hydroxyl group. Examples of the polyol include polyether polyol, polyester polyol, polycarbonate polyol, and the like, and can be appropriately selected based on flexibility, heat resistance, chemical resistance, and the like.

Examples of the isocyanate compound include aromatic aromatic compounds such as tolylene diisocyanate, diphenylmethane diisocyanate, naphthalene diisocyanate, xylylene diisocyanate, and tetramethylxylylene diisocyanate. Group diisocyanates; such as 1,4-cyclohexane diisocyanate, isophorone diisocyanate, 4,4'-dicyclohexylmethane diisocyanate, methylcyclohexane diisocyanate, isopropylene dicyclohexyl- Alicyclic diisocyanates such as 4,4'-diisocyanate, 1,3-diisocyanatomethylcyclohexane, 4-methyl-1,3-cyclohexylene diisocyanate, etc.

The compound having a (meth)acrylyl group may be a monofunctional (meth)acrylate having one (meth)acrylyl group in the molecule, or it may be a compound having two or more (meth)acrylates in the molecule. Polyfunctional (meth)acrylates of acyl groups. The compound having a (meth)acrylyl group preferably contains a polyfunctional (meth)acrylate.

Examples of the monofunctional (meth)acrylate include: (methyl)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, isopropyl (meth)acrylate, (meth)acrylate Butyl acrylate, amyl(meth)acrylate, isobutyl(meth)acrylate, tert-butyl(meth)acrylate, pentyl(meth)acrylate ), isopentyl (meth)acrylate, hexyl (meth)acrylate, heptyl (meth)acrylate, octyl (meth)acrylate, isooctyl (meth)acrylate, (meth)acrylic acid 2 -Ethylhexyl, nonyl (meth)acrylate, decyl (meth)acrylate, iso(meth)acrylate Decyl ester, undecyl (meth)acrylate, dodecyl (meth)acrylate, lauryl (meth)acrylate, stearyl (meth)acrylate, isostearyl (meth)acrylate, Isobornyl (meth)acrylate, 1-adamantyl (meth)acrylate, 2-methyl-2-adamantyl (meth)acrylate, 2-ethyl-2-adamantyl (meth)acrylate Alkyl ester, bornyl (meth)acrylate, tricyclodecyl (meth)acrylate, dicyclopentyl (meth)acrylate, dicyclopentenyl (meth)acrylate, cyclohexyl (meth)acrylate Ester, benzyl (meth)acrylate, 1-naphthylmethyl (meth)acrylate, 2-naphthylmethyl (meth)acrylate, phenoxyethyl (meth)acrylate, (meth)acrylate Phenoxy-2-methylethyl acrylate, phenoxyethoxyethyl (meth)acrylate, 3-phenoxy-2-hydroxypropyl (meth)acrylate, (meth)acrylic acid 2-Phenylphenoxyethyl ester, 4-phenylphenoxyethyl (meth)acrylate, 3-(2-phenylphenyl)-2-hydroxypropyl (meth)acrylate, (meth)acrylate 2-hydroxyethyl acrylate, 2-hydroxypropyl (meth)acrylate, 2-hydroxybutyl (meth)acrylate, tetrahydrofurfuryl (meth)acrylate, butoxyethyl (meth)acrylate, ethanol Oxydiethylene glycol (meth)acrylate, polyethylene glycol mono(meth)acrylate, polypropylene glycol mono(meth)acrylate, methoxyethylene glycol (meth)acrylate, ethoxy Ethyl (meth)acrylate, methoxypolyethylene glycol (meth)acrylate, methoxypolypropylene glycol (meth)acrylate, etc.

Examples of polyfunctional (meth)acrylates include difunctional (meth)acrylates, trifunctional (meth)acrylates, tetrafunctional (meth)acrylates, and the like. Specific examples include: 1,4-butanediol di(meth)acrylate, 1,6-hexanediol di(meth)acrylate, and 1,9-nonanediol di(meth)acrylic acid. Ester, ethylene glycol di(meth)acrylate, diethylene glycol di(meth)acrylate, neopentyl glycol di(meth)acrylate, triethylene glycol di(meth)acrylate, tetraethylene glycol di(meth)acrylate Alcohol di(meth)acrylate, polyethylene glycol di(meth)acrylate, trimethylolpropane tri(meth)acrylate, pentaerythritol tri(meth)acrylate, pentaerythritol tetra(meth)acrylate Esters, dipentaerythritol penta(meth)acrylate, dipentaerythritol hexa(meth)acrylate, tripentaerythritol tetra(meth)acrylate, tripentaerythritol penta(meth)acrylate Esters, tripentaerythritol hexa(meth)acrylate, tripentaerythritol hepta(meth)acrylate, tripentaerythritol eight(meth)acrylate, etc.

The curable composition may or may not contain a non-ultraviolet curable resin in addition to the ultraviolet curable compound. In addition, the curable composition may contain a photopolymerization initiator. In addition, the curable composition may contain additives and solvents as necessary. Examples of the additives include inorganic particles, resin particles, antifouling agents, dispersants, leveling agents, defoaming agents, thixotropic agents, antibacterial agents, flame retardants, slip agents, and the like.

Examples of non-ultraviolet curable resins include thermoplastic resins, thermosetting resins, and the like. Examples of thermoplastic resins include polyester resin, polyether resin, polyolefin resin, polyamide resin, and the like. Examples of thermosetting resins include unsaturated polyester resin, epoxy resin, alkyd resin, phenolic resin, and the like.

Examples of the photopolymerization initiator include alkylphenone-based photopolymerization initiators, acylphosphine oxide-based photopolymerization initiators, and oxime ester-based photopolymerization initiators. Examples of alkylphenone-based photopolymerization initiators include: 2,2'-dimethoxy-1,2-diphenylethane-1-one, 1-hydroxy-cyclohexyl-phenyl-one, 2 -Hydroxy-2-methyl-1-phenyl-propan-1-one, 1-[4-(2-hydroxyethoxy)-phenyl]-2-hydroxy-2-methyl-1-propane- 1-one, 2-hydroxy-1-{4-[4-[2-(2-hydroxy-2-methyl-propyl)-benzyl]phenyl]-2-methyl-propane-1- Ketone, 2-methyl-1-[4-(methylthio)phenyl]-2-morpholinopropan-1-one, 2-benzylmethyl-2-(dimethylamino)-1- (4-morpholinophenyl)-1-butanone, 2-(dimethylamino)-2-[(4-methylphenyl)methyl]-1-(4-morpholinophenyl) -1-Butanone, 2-(4-methylbenzyl)-2-(dimethylamino)-1-(4-morpholinophenyl)-1-butanone, N,N-dimethyl Aminoacetophenone, etc. Examples of the acylphosphine oxide-based photopolymerization initiator include: 2,4,6-trimethylbenzyldiphenylphosphine oxide, bis(2,4,6-trimethylbenzyldiphenyl)- Phenylphosphine oxide, bis(2,6-dimethoxybenzoyl)-2,4,4-trimethyl-pentylphosphine oxide, etc. Examples of the oxime ester photopolymerization initiator include: 1,2-octanedione, 1- [4-(phenylthio)phenyl]-2-(O-benzoyl oxime), ethanone-1-[9-ethyl-6-(2-methylbenzoyl)-9H-carb Azol-3-yl]-1-(O-acetyl oxime), etc. The photopolymerization initiator can be used alone or in combination of two or more types.

The content of the photopolymerizer initiator is preferably 0.1% to 10% by mass, more preferably 1% to 5% by mass in the total solid content of the curable composition.

Inorganic particles and resin particles are added for the purpose of preventing adhesion of the hard coat layer, increasing the hardness of the hard coat layer, and imparting anti-glare properties. Examples of the inorganic particles include metal oxide particles formed of oxides of metals such as silicon dioxide, titanium, zirconium, tin, zinc, silicon, niobium, aluminum, chromium, magnesium, germanium, gallium, antimony, and platinum. These inorganic particles can be used alone or in combination of two or more types. Among these, from the viewpoint of having both high hardness and transparency, titanium oxide particles, zirconium oxide particles, and tin oxide particles are preferred.

Examples of the resin particles include: (meth)acrylic resin, styrene resin, styrene-(meth)acrylic resin, polyurethane resin, polyamide resin, silicone resin, epoxy resin, phenolic resin, Resin particles formed from polyethylene resin, cellulose and other resins. These resin particles can be used alone or in combination of two or more types.

Examples of antifouling agents include fluorine-containing compounds. Examples of the fluorine-containing compound include perfluoroalkyl group-containing (meth)acrylate. Examples of such compounds include "X-71-1203M" manufactured by Shin-Etsu Chemical Industry, "MEGAFACE ^TM RS-75" manufactured by DIC Corporation, "Optool ^TM DAC-HP" manufactured by Daikin Industries, and "Futagent ^TM" manufactured by NEOS Corporation. 601AD" etc. The fluorine-containing compound can suppress the adhesion of dirt and fingerprints and can easily remove dirt and fingerprints. The content of the fluorine-containing compound in the total amount of the hard coat layer 32b is preferably 0.01 mass% to 15 mass%, more preferably 0.05 mass% to 10 mass%, and most preferably 0.2 mass% to 5 mass%. When the content of the fluorine-containing compound is within the above range, excellent antifouling properties and anti-fingerprint properties can be obtained.

Examples of the solvent used for the curable composition that forms the hard coat layer 32b include alcoholic solvents (such as ethanol, isopropyl alcohol, n-butanol, ethylene glycol monomethyl ether, ethylene glycol monoisomethyl ether, propylene glycol). Monomethyl ether, diethylene glycol monobutyl ether, etc.), ketone solvents (such as methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone, acetone, etc.), aromatic solvents (toluene, xylene, etc.), ester solvents (such as ethyl acetate, propyl acetate, isopropyl acetate, butyl acetate, etc.), amide solvents (N-methylpyrrolidone, acetamide, dimethylformamide, etc.), etc. These solvents can be used alone or in combination of two or more.

The solid content concentration (concentration of components other than the solvent) of the curable composition may be appropriately determined in consideration of coatability, film thickness, etc., and is, for example, 1 to 90 mass %, preferably 1.5 to 80 mass %. mass %, optimally 2 mass % to 70 mass %.

(Manufacture of covering film)

The cover film can be produced by forming a hard coat layer 32b on one surface of the cover film base material 32a. The hard coat layer 32b can be formed by applying a composition for forming the hard coat layer on the surface covering the side of the base material 32a, and then drying, ultraviolet irradiation, etc. are performed as necessary.

In order to improve the adhesion between the cover film base material 32a and the hard coating layer 32b, preferably, corona treatment, plasma treatment, hot air treatment, ozone treatment, and ultraviolet treatment can be applied to the surface of the cover film base material 32a. and other surface treatments. In addition, an easy-adhesion layer may be provided on the surface of the cover film base material 32a. In addition, various functional layers such as a gas barrier improvement layer, an antistatic layer, and an oligomer barrier layer may be provided on the surface of the cover film base material 32a. In addition, another hard coating layer may be provided between the cover film base material 32a and the adhesive layer 12.

Regarding coating of the composition used to form the hard coat layer 32b, coating methods (such as reverse gravure coating, direct gravure coating, die coating, rod coating, wire rod coating) may be used. cloth method, roller coating method, spin coating method, dip coating method, spray coating method, knife coating method, kiss coating method, etc.), inkjet method, printing method (offset printing, screen printing, flexographic printing, etc.).

Drying is not particularly limited as long as the solvent etc. used in the coating liquid can be removed. Preferably, it is carried out at 50°C to 150°C for about 10 seconds to 180 seconds, and more preferably at 50°C to 120°C.

Regarding ultraviolet irradiation, a high-pressure mercury lamp, an electrodeless (microwave) lamp, a xenon lamp, a metal halide lamp, or any other ultraviolet irradiation device can be used. Ultraviolet irradiation can be performed in an inert gas atmosphere such as nitrogen if necessary. The amount of ultraviolet irradiation is not particularly limited, but is preferably 50mJ/cm ² ~800mJ/cm ² , and more preferably 100mJ/cm ² ~300mJ/cm ² .

(Polarizing film)

The polarizing film may be, for example, a protective layer bonded to at least one surface of the polarized photon via an adhesive layer. In addition, other optically functional films such as retardation films and barrier films can also be laminated on the polarizer or the protective film via an adhesive layer or adhesive material.

The polarizer is a film that has the function of transmitting only light polarized in a specific direction. For example, a polyvinyl alcohol-based resin film that is uniaxially stretched and iodine-oriented can be used. The thickness of the polarized photons can be, for example, 1 μm to 12 μm, preferably 1 μm to 9 μm, and more preferably 3 μm to 6 μm.

Regarding the protective film, the same base material as that used for the cover film can be used. The thickness of the protective film is not particularly limited, but from the viewpoint of operability, it is preferably 2 μm to 500 μm, and more preferably 2 μm to 200 μm.

In addition, this protective film can also function as a retardation film. Retardation film is an optical film that exhibits optical anisotropy and can be formed by stretching a film made of resin that can be used as a protective film, or by coating a liquid crystal compound on a base film and Orientation and solidification form the square Law etc. When the polarizing film is used as an anti-reflection circular polarizing plate for an organic EL display device, preferably, the phase difference film: imparts a phase difference of λ/4 (90°) and changes the linearly polarized light to Circularly polarized λ/4 plate.

[Example]

The present invention will be described in further detail below based on specific embodiments. The present invention is not limited to the following examples, and can be implemented with appropriate modifications within the scope of the gist. In addition, the polymerization rate, weight average molecular weight (Mw), molecular weight distribution (PDI) of the block copolymer, gel fraction of the adhesive material, thickness of the adhesive layer, Young's modulus, elastic modulus during shrinkage, shear storage Energy elastic modulus, shear stress, recovery rate, etc. are evaluated according to the following methods.

In addition, the meanings of abbreviations are as follows.

BA: n-butyl acrylate

LA: Lauryl acrylate

EHA: 2-ethylhexyl acrylate

IBXA: Isobornyl acrylate

ACMO: Acrylylmorpholine

AA: acrylic

HBA: 4-hydroxybutyl acrylate

DMAAm: Dimethylacrylamide

BTEE: Ethyl-2-methyl-2-n-butyltellurium-propionate

AIBN: Azobisisobutyronitrile

AcOEt: Ethyl acetate

(polymerization rate)

¹ H-NMR (solvent: CDCl ₃ , internal standard: TMS) was measured using a nuclear magnetic resonance (NMR) measurement device (manufactured by Bruker Beispin, model: AVANCE500 (frequency 500 MHz)). Regarding the obtained NMR spectrum, the integrated ratio of the peaks derived from the vinyl group derived from the monomer and the ester side chain derived from the polymer was calculated, and the polymerization rate of the monomer was calculated.

(Weight average molecular weight (Mw) and molecular weight distribution (PDI))

Calculation was performed by gel permeation chromatography (GPC) using a high-speed liquid chromatograph (model HLC-8320GPC manufactured by Tosoh Co., Ltd.). Two strips of TSKgel Super Multipore HZ-H (manufactured by Tosoh Corporation) were used as the column, a tetrahydrofuran solution was used as the mobile phase, and a differential refractometer was used as the detector. The measurement conditions are set as follows: column temperature is 40°C, sample concentration is 10 mg/mL, sample injection volume is 10 μm, and flow rate is 0.2 mL/min. Using polystyrene (molecular weight 2,890,000, 1,090,000, 775,000, 427,000, 190,000, 96,400, 37,900, 10,200, 2,630,440) as a standard material, prepare a calibration curve (calibration curve) and measure the weight average molecular weight (Mw) and number average molecular weight (Mn) ). From the measured values, the molecular weight distribution (PDI=Mw/Mn) was calculated.

(gel fraction)

Measure the mass W1 of the metal mesh (400 mesh) cut out with a width of 50mm and a length of 120mm. Collect 0.1g of sheet-like adhesive material, wrap the adhesive material with a metal mesh to prevent it from falling off, and then make a test piece, and measure the mass W2 of this test piece. The test piece was put into a glass bottle, and 40 g of ethyl acetate was injected into the bottle, and then shaken gently, and then left to stand at normal temperature (25° C.) for 76 hours. After standing, take it out from the glass bottle The pieces were tested and left at room temperature for 12 hours, and further dried in a vacuum oven at 100°C for 4 hours. Cool the dried test piece to room temperature and measure the mass W3, and calculate the gel fraction according to the following formula.

Gel fraction (mass %) = ((W3-W1)/(W2-W1))×100

(Young's modulus)

Cut the sheet-like adhesive material (thickness 1mm) into a size of 5mm width and 70mm length to make a test piece. The tensile test was performed using a precision universal testing machine (manufactured by Shimadzu Corporation, using AUTOGRAPH ^TM AGX). The test was carried out in an environment of 23°C and 50%, with the distance between clamps set to 30mm, the tensile speed 30mm/min, and the tensile stress increased from 0kPa to 50kPa. Regarding the obtained stress-strain curve, the average value of the tangent slope at a distance between clamps of 30.9 to 31.8 mm (displacement of 3 to 6% from the initial distance between clamps) was used as the Young's modulus.

(modulus of elasticity during contraction)

Cut the sheet-like adhesive material (thickness 1mm) into a size of 5mm width and 70mm length to make a test piece. The tensile test was performed using a precision universal testing machine (manufactured by Shimadzu Corporation, using AUTOGRAPH ^TM AGX). The test was conducted in an environment of 23°C and 50%, with the distance between clamps set to 30mm and the tensile speed set to 30mm/min. After stretching so that the tensile stress reaches 50 kPa from 0 kPa, it is shrunk so that the tensile stress becomes 0 kPa, and the tensile stress at each elongation rate during shrinkage is recorded. This stretching and contraction was repeated 10 times, and the elastic modulus at the time of the first contraction and the 10th contraction was calculated.

Regarding the shrinkage elastic modulus, when the displacement from the length of the test piece under the tensile stress of 50 kPa at the n-th contraction to the length of the test piece at the tensile stress of 0 kPa at the n-th contraction is set to 1, the displacement is 0.97 The tensile stress under and the tensile stress under displacement 0.94 are calculated.

(Adhesive layer thickness)

Using a thickness measuring machine (using "TH-104" manufactured by Testing Machine Industry Co., Ltd.), the total thickness of the entire adhesive sheet is measured, and the thickness of the adhesive layer is calculated by dividing the total thickness by the thickness of the peeling sheet.

(Shear storage elastic modulus, shear loss elastic modulus)

The adhesive layer (sheet-like adhesive material) constituting the adhesive sheet is bonded and laminated using a manual roller to produce a laminated body with a thickness of 0.5 mm. This laminate was used as a sample, and a viscoelasticity measuring device (Discovery HR-2 manufactured by Texas Instruments) was used at 23°C 50% environment and in shear mode, geometry: 8 mm diameter parallel plate, frequency: 1Hz, strain: below 1%, measure shear energy storage elastic modulus and shear loss elastic modulus.

(Stress and recovery rate when shear stress is applied and maintained for 10 minutes)

The adhesive layer (sheet-like adhesive material) constituting the adhesive sheet is bonded and laminated using a manual roller to produce a laminated body with a thickness of 0.5 mm. This laminated body was used as a sample, and a viscoelasticity measuring device (Discovery HR-2 manufactured by Texas Instruments) was used to measure at 23°C 50% environment: Immediately after applying shear stress, the parallel plate with a diameter of 8 mm had a 200 % strain; and the stress after continuous application of shear stress for 10 minutes.

Next, the applied shear stress was released, the shear stress was set to 0 kPa, and the strain when it was left to stand for 10 minutes was measured. From the obtained strain, the recovery rate (%) was calculated according to the following equation.

Recovery rate (%) = (200-strain after being left for 10 minutes)/200

(adhesion)

Peel off the release sheet on one side of the adhesive sheet from the adhesive layer, and laminate a polyethylene terephthalate (PET) film (Toyobo ^EsterTM Film Film E5100: Toyobo, thickness 50 μm) on the adhesive layer. , peel off the release sheet on the other side from the adhesive layer, and laminate the adhesive layer to the polyimide film (Capton ^TM 200V: Toray Co., Ltd., thickness 50 μm) by moving a 2kg roller back and forth twice.

After laminating for 1 hour, cut out the size with a width of 25mm and a length of 150mm. According to the method of JIS Z 0237 (2009), use a precision universal testing machine (AUTOGRAPH ^TM AGS-1kNX, 50N load cell) manufactured by Shimadzu, and test at 23℃ Under the conditions of 50% environment, peeling speed 0.5mm/s, and peeling angle 180°, measure the adhesion of the adhesive layer to the polyimide film.

(repeated bending test)

Peel off the release sheet on one side of the adhesive sheet from the adhesive layer, and laminate a polyethylene terephthalate (PET) film (Toyobo ^EsterTM Film Film E5100: Toyobo, thickness 50 μm) on the adhesive layer. , peel off the release sheet on the other side from the adhesive layer, and laminate the adhesive layer to the polyethylene terephthalate (PET) film (Diafoil ^TM T330E: Mitsubishi Chemical Co., Ltd. by moving a 2kg roller back and forth twice). , thickness 150μm).

The obtained test piece for the bending test was cut into a size of 25 mm in width and 90 mm in length, with the polyethylene terephthalate (PET) film side with a thickness of 150 μm as the outside, and the two short sides were fixed on a durable Put it on a testing machine (manufactured by Yuasa System Machinery Co., Ltd., planar body unloaded U-shaped telescopic testing machine, "DLDM111LH") and bend it at a bending diameter (inner diameter‧diameter) of 5 mm and a reciprocating speed of 60 spm (bending 60 times per minute). ) to bend it 200,000 times. The test piece taken out from the testing machine was visually observed and evaluated based on the following standards.

○: There is no floating or peeling between the polyester film and the adhesive layer, and no cracks.

×: There is floating or peeling between the polyester film and the adhesive layer, or there are cracks.

<Manufacture of copolymer>

(Synthesis Example 1: Copolymer No.A)

Butyl acrylate (BA, 1742.0g), acrylic acid (AA, 3.6g), 4-hydroxybutyl acrylate (HBA, 54.0g), azobisisobutyronitrile (AIBN, 87.6mg), ethyl acetate (AcOEt , 1340g) into a flask equipped with an argon gas introduction tube and a stirrer, and replace it with argon gas. Add 1,2-bis(triethoxysilyl)ethane (BTEE, 400mg) at 60°C. This was allowed to react for 24 hours to proceed with polymerization.

After the reaction is completed, AcOEt is added to the reaction solution to obtain a copolymer solution containing copolymer No. A. The Mw of the obtained copolymer No. A was 894,000, the PDI was 2.06, and the solid content of the solution was 20.1 mass %.

(Synthesis Examples 2~6: Copolymer No.B~F)

Copolymers No.B to F were produced in the same manner as the production method of copolymer No.A. Table 2 shows the raw material monomers, organic tellurium compounds, azo polymerization initiators, solvents, reaction conditions, and polymerization rates used. In addition, Table 3 shows the composition, Mw, PDI, and glass transition temperature of each copolymer.

(Synthesis Example 7: Copolymer No.G)

Put BA (364.5g), acrylomorpholine (ACMO, 67.5g), acrylamide (AA, 13.5g), HBA (4.5g), and AcOEt (276.5g) into an argon gas introduction tube and a dropping funnel. and stirrer in the flask, replace it with argon gas, and raise the temperature to 80°C. What was prepared by dissolving AIBN (197.1 mg) in AcOEt (45 g) was added over 2 hours, and the mixture was reacted for 4 hours to perform polymerization.

After the reaction is completed, AcOEt is added to the reaction solution to obtain a copolymer solution containing copolymer No. F. The Mw of the obtained copolymer No. F was 873,000, the PDI was 6.48, and the solid content of the solution was 20.0 mass %.

(Synthesis Example 8: Copolymer No.H)

Copolymer No.H was produced in the same manner as in the production method of copolymer No.G. Table 2 shows the raw material monomers, azo polymerization initiators, solvents, reaction conditions, and polymerization rates used. In addition, Table 3 shows the composition, Mw, PDI, and glass transition temperature of each copolymer.

<Manufacture of adhesive composition>

(Adhesive composition No. 1)

To 100 parts by mass of the copolymer component of copolymer No. A obtained in Synthesis Example 1, 0.076 parts by mass of a cross-linking agent (Duranate ^TM TPA-100) and 0.023 parts by mass of a cross-linking accelerator (Neostan ^TM U -810), 0.33 parts by mass of a cross-linking retarder (acetyl acetone), 30 parts by mass of a tackifier (FTR ^TM 6100), and AcOEt, and stirred to obtain adhesive composition No. 1.

(Adhesive composition No.2~16)

Adhesive compositions No. 2 to 16 were prepared in the same manner as adhesive composition No. 1, except that the formula was changed to that described in Table 4.

[Table 4]

TETRAD ^TM -C: Mitsubishi Gas Chemical Co., Ltd., 1,3-bis(N,N-diglycidylaminoethyl)cyclohexane (epoxy group amount; 9.76mmol/g)

TPA-100: Made by Asahi Kasei Co., Ltd., Duranate ^TM TPA-100 (isocyanurate form of hexamethylene diisocyanate (NCO%; 23.01 mass%))

U-810: Made by Nitto Kasei Co., Ltd., Neostan ^TM U-810 (dioctyl tin)

AcAc; acetyl acetone

FTR6100: Mitsui Chemicals, FTR ^TM 6100 (aromatic resin)

FTR8120: Mitsui Chemicals, FTR ^TM 8120 (aromatic resin)

<Sheet adhesive material>

Use a release sheet (polyethylene terephthalate (PET) film with release treatment on the surface, Clean Sepa ^TM HY-S10: manufactured by Higashiyama Film Co., Ltd., thickness 38 μm) so that the surface with release treatment is on the inside , make a container with a length of 70mm×width of 70mm×height of 20mm. Each adhesive composition was added to this container in such a way that the film thickness after drying was 1.0 mm, and dried at 60°C for 12 hours using a constant temperature dryer, and then taken out from the container to produce a sheet. Adhesive materials. Table 5 shows the evaluation results of each sheet-shaped adhesive material.

[table 5]

As shown in Table 5, sheet-like adhesive materials No. 1 to 13 are cured products of an adhesive composition containing a (meth)acrylic copolymer having a reactive functional group and a cross-linking agent, and are made of (meth) acrylic acid It is a copolymer obtained through living free radical polymerization. The adhesive material has a predetermined Young's modulus and a maintenance rate of the elastic modulus during shrinkage.

<Manufacturing of adhesive sheets>

Using a Baker-type coater, apply the adhesive composition to the first release sheet (PET film with release treatment on the surface, Clean Sepa ^TM HY-S10: Higashiyama) so that the film thickness after drying is 25 μm. film, thickness 38 μm) on the release surface, use a constant temperature dryer to dry at 120°C for 3 minutes. Next, the adhesive layer formed on the first release sheet was bonded to the release surface of the second release sheet (PET film with release treatment on the surface, Clean Sepa ^TM HY-S10: manufactured by Higashiyama Film Co., Ltd., thickness 38 μm), Aging was performed at 40°C for 3 days to produce an adhesive layer sandwiched between two peeling sheets. The evaluation results of each adhesive sheet are shown in Table 6.

As shown in Table 6, in the adhesive sheets Nos. 21, 22, 23 and 25, the adhesive layers are formed from the sheet-like adhesive materials Nos. 4, 9, 11 and 13. Even if these adhesive sheets are repeatedly bent, they will not float or peel at the interface between the adhesive layer and the flexible component at the bend, thereby suppressing the occurrence of appearance defects such as cracks and ripples.

[Industrial Applicability]

The adhesive material of the present invention can be used to bond one flexible component (such as a functional component) and another flexible component (such as a display element) used to form a flexible display (which can be repeatedly bent and stretched). .

Claims (9)

An adhesive material, characterized in that it is used to bond one flexible member and another flexible member, and the adhesive material is a (meth)acrylic copolymer containing reactive functional groups and an intersection The cured product of the adhesive composition of the joint agent, the (meth)acrylic copolymer is obtained through living free radical polymerization, and its molecular weight distribution (Mw/Mn) is less than 3.0, and the adhesive material is at 23°C. The shear energy storage elastic modulus is 0.8×10 ⁴ Pa~30×10 ⁴ Pa, and the Young’s modulus of the adhesive material is 10kPa~1000kPa. After the adhesive material is elongated until the tensile stress reaches 50kPa, the tension is released. When the elongation and contraction test is repeated 10 times, the ratio of the elastic modulus at the 10th contraction to the elastic modulus at the 1st contraction is 60% or more. The adhesive material according to claim 1, wherein the weight average molecular weight of the (meth)acrylic copolymer is 200,000 to 2,000,000. The adhesive material according to claim 1 or 2, wherein the reactive functional group is a carboxyl group and/or a hydroxyl group. The adhesive material according to claim 1, wherein the cross-linking agent has an epoxy group and/or an isocyanate group. An adhesive sheet, characterized by having: an adhesive layer for bonding one flexible member and another flexible member; and a flexible sheet member that is bonded to at least one of the adhesive layers. On the side surface, Wherein, the adhesive layer is formed of the adhesive material described in any one of claims 1 to 4. The adhesive sheet according to claim 5, wherein the adhesive sheet has: a first flexible sheet member that is attached to the surface of one side of the adhesive layer; a second flexible sheet member , which is attached to the surface of the other side of the adhesive layer, wherein the first flexible sheet member is a first peeling sheet, and the second flexible sheet member is a second peeling sheet. The first release sheet and the second release sheet are bonded together with their respective release surfaces in contact with the adhesive layer. A flexible laminated member, characterized by comprising: a first flexible member; a second flexible member; and an adhesive layer for connecting the first flexible member and the second flexible member. The elastic components are adhered to each other, wherein the adhesive layer is formed of the adhesive material as described in any one of claims 1 to 4. The flexible laminated member according to claim 7, wherein at least one of the first flexible member and the second flexible member is a display element. A mobile terminal, characterized by having a flexible laminated member as described in claim 7 or 8.

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