KR101800470B1 - Pressure-sensitive adhesive tape, laminate, and image display device - Google Patents

Abstract

일반식 (1) 중, R¹ 은 수소 원자 또는 메틸기를 나타내고, R² 는 탄소수 3 ∼ 14 의 알킬기를 나타낸다. R² 의 알킬기의 수소 원자는 시클로알킬기로 치환되어 있어도 된다.An adhesive tape excellent in transparency and excellent in adhesion to a polycarbonate plate and an acrylic plate and capable of suppressing lifting peeling occurring at an interface with a polycarbonate plate or an acrylic plate even under a high temperature condition is provided. Further, a laminate and an image display device manufactured using the adhesive tape are provided.
The present invention relates to a pressure-sensitive adhesive tape having a pressure-sensitive adhesive layer comprising a pressure-sensitive adhesive composition containing a copolymer, wherein the copolymer has a structural unit derived from a monomer having a bicyclo ring structure and one olefinic double bond in the molecule, (Meth) acrylic acid ester monomer having a structure represented by the following formula (1) and having a constitutional unit derived from a monomer having a bicyclo ring structure and one olefinic double bond in the molecule, which is contained in 100 parts by weight of the copolymer The proportion of the constituent unit is 10 to 60 parts by weight and the proportion of the constituent unit derived from the (meth) acrylic acid ester monomer having the structure represented by the general formula (1) in 100 parts by weight of the copolymer is 30 to 90 parts by weight , The total light transmittance in the visible light wavelength region is 90% or more and the haze value is 1 It is greater than the adhesive tape.
[Chemical Formula 1]

In the general formula (1), R ¹ represents a hydrogen atom or a methyl group, and R ² represents an alkyl group having 3 to 14 carbon atoms. The hydrogen atom of the alkyl group of R ² may be substituted with a cycloalkyl group.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to an adhesive tape, a laminate, and an image display device.

The present invention relates to a pressure-sensitive adhesive tape having high transparency and excellent adhesive strength to a polycarbonate plate and an acrylic plate, and capable of suppressing lifting peeling occurring at an interface with a polycarbonate plate or an acrylic plate even under high temperature conditions. The present invention also relates to a laminate and an image display device manufactured using the adhesive tape.

2. Description of the Related Art Recently, a display panel or a touch panel is used in an image display device such as a cellular phone, a portable information terminal, or the like, or an image display device in various fields. In such an image display apparatus, for example, a protective plate for protecting the surface through a transparent pressure-sensitive adhesive layer is stuck to a display panel or a touch panel. In recent years, a polycarbonate plate, An acrylic plate or the like is generally used.

However, it is known that the polycarbonate plate and the acrylic plate are easy to absorb moisture, and under high temperature condition, moisture is vaporized and outgas is produced. Therefore, under high temperature conditions, outgassing causes a problem that lifting peeling occurs at the interface between the polycarbonate plate or the acrylic plate and the pressure-sensitive adhesive layer to cause appearance defects. In order to prevent defective appearance due to lifting peeling, for example, the molecular weight of the acrylic polymer forming the pressure-sensitive adhesive layer is appropriately adjusted. In this way, a pressure-sensitive adhesive layer capable of sufficiently suppressing lifting peeling can be obtained .

For example, Patent Document 1 discloses a double-sided pressure-sensitive adhesive tape or sheet having transparency, in which a transparent pressure-sensitive adhesive layer is formed on both surfaces of a transparent substrate, and a transparent pressure-sensitive adhesive layer formed on at least one surface of the transparent substrate, A transparent double-sided pressure-sensitive adhesive tape or sheet formed from a pressure-sensitive adhesive composition containing a specific acrylic polymer (a) and an oligomer (b) is disclosed. In the patent document 1, the acrylic polymer (a) is obtained by copolymerizing (meth) acrylic acid alkyl ester having an alkyl group of 4 to 12 carbon atoms as a monomer main component and a monomer containing a carboxyl group as a monomer component in an amount of 3 To 10 parts by weight and a weight average molecular weight of 500,000 to 900,000 and the oligomer (b) has a glass transition temperature of 60 to 190 占 폚 when the homopolymer is formed and the cyclic Structure is contained as a monomer main component and a carboxyl group-containing monomer as a monomer component is contained in an amount of 3 to 10 parts by weight based on 100 parts by weight of the total monomer components and an oligomer having a weight average molecular weight of 3,000 to 6,000.

Patent Document 1 discloses that the transparent double-sided pressure-sensitive adhesive tape or sheet described in this document has excellent lifting and peeling resistance, and is also excellent in transparency and anti-bending property. However, since the transparent double-faced pressure-sensitive adhesive tape or sheet described in Patent Document 1 uses two kinds of polymers or oligomers in combination, there is a problem that the compatibility of two kinds of polymers or oligomers is not sufficient, It has been difficult to realize high transparency sufficient for application.

Japanese Patent Application Laid-Open No. 2005-255877

It is an object of the present invention to provide an adhesive tape which has high transparency and is excellent in adhesion to polycarbonate plates and acrylic plates and which can suppress lifting peeling occurring at the interface with polycarbonate plates or acrylic plates even under high temperature conditions . It is another object of the present invention to provide a laminate and an image display device manufactured using the adhesive tape.

The present invention relates to a pressure-sensitive adhesive tape having a pressure-sensitive adhesive layer comprising a pressure-sensitive adhesive composition containing a copolymer, wherein the copolymer has a structural unit derived from a monomer having a bicyclo ring structure and one olefinic double bond in the molecule, (Meth) acrylic acid ester monomer having a structure represented by the following formula (1) and having a constitutional unit derived from a monomer having a bicyclo ring structure and one olefinic double bond in the molecule, which is contained in 100 parts by weight of the copolymer The proportion of the constituent unit is 10 to 60 parts by weight and the proportion of the constituent unit derived from the (meth) acrylic acid ester monomer having the structure represented by the general formula (1) in 100 parts by weight of the copolymer is 30 to 90 parts by weight , The total light transmittance in the visible light wavelength region is 90% or more and the haze value is 1 It is greater than the adhesive tape.

[Chemical Formula 1]

In the general formula (1), R ¹ represents a hydrogen atom or a methyl group, and R ² represents an alkyl group having 3 to 14 carbon atoms. The hydrogen atom of the alkyl group of R ² may be substituted with a cycloalkyl group.

Hereinafter, the present invention will be described in detail.

It is considered that the lifting peeling occurring at the interface between the polycarbonate plate or the acrylic plate and the pressure-sensitive adhesive layer under the high-temperature condition is caused by the outgass being generated from the polycarbonate plate or the acrylic plate and the bubbles growing by the gas pressure . Therefore, in order to suppress the lifting peeling, it is conceivable that the adhesion of the pressure-sensitive adhesive layer to the polycarbonate plate and the acrylic plate is increased, thereby preventing bubble growth at the interface with the polycarbonate plate or the acrylic plate.

The present inventors have found that a pressure-sensitive adhesive containing a copolymer having a constituent unit derived from a monomer having a bicyclo ring structure and one olefinic double bond in a molecule and a constituent unit derived from a (meth) acrylic acid ester monomer having a specific structure By using the composition, it has been found that a pressure-sensitive adhesive layer having a dramatically improved adhesion to a polycarbonate plate and an acrylic plate can be formed. The present inventors have found that an adhesive tape having a pressure-sensitive adhesive layer made of such a pressure-sensitive adhesive composition and having a total light transmittance and a haze value within a predetermined range has a high transparency and can be lifted at an interface with a polycarbonate plate or an acrylic plate And peeling can be suppressed. Thus, the present invention has been accomplished. Further, (meth) acryl means acryl or methacryl.

The pressure-sensitive adhesive tape of the present invention has a pressure-sensitive adhesive layer comprising a pressure-sensitive adhesive composition containing a copolymer.

The copolymer has a constituent unit derived from a monomer having a bicyclo ring structure and one olefinic double bond in the molecule. Since the copolymer has a constitutional unit derived from a monomer having a bicyclo ring structure and one olefinic double bond in the molecule, the adhesive tape of the present invention greatly improves the adhesive force to the polycarbonate plate and the acrylic plate.

The bicyclic ring structure is not particularly limited, and examples of the functional group having the bicyclo ring structure include a bicyclo [1.1.0] butyl group, a bicyclo [1.1.1] pentyl group, a bicyclo [2.1. Cyclohexyl [2.2.0] hexyl group, a bicyclo [2.2.1] heptyl group, a bicyclo [3.1.0] hexyl group, a bicyclo [2.1.1] hexyl group, a bicyclo [2.2.0] 3] heptyl group, a bicyclo [3.2.1] heptyl group, a bicyclo [3.2.0] heptyl group, a bicyclo [4.1.0] heptyl group, a bicyclo [2.2.2] octyl group, a bicyclo [3.2.1] 3] octyl group, a bicyclo [4.1.1] octyl group, a bicyclo [4.2.0] octyl group, a bicyclo [5.1.0] octyl group, a bicyclo [3.2.2] nonyl group, a bicyclo [3.3. Non-cyclo [4.2.1] nonyl group, a bicyclo [4.3.0] nonyl group, a bicyclo [5.1.1] nonyl group, a bicyclo [5.2.0] nonyl group, a bicyclo [6.1. 0] nonyl group, a bicyclo [4.3.1] decyl group, and a part of the hydrogen atoms of the functional group having a bicyclo ring structure as a chained alkyl group or a cyclic alkyl group And the like functional group having a structure in which substituted. The substitution may be a single point or a plurality of points. Of these functional groups having a bicyclo ring structure, a norbornyl group and an isobornyl group are preferable, and an isobornyl group is particularly preferable.

The olefinic double bond is not particularly limited, and examples of the functional group having an olefinic double bond include a (meth) acryloyl group, a vinyl group, and an allyl group. Among these functional groups having an olefinic double bond, a (meth) acryloyl group is preferable. Further, (meth) acryloyl means acryloyl or methacryloyl.

The monomer having a bicyclo ring structure and one olefinic double bond in the molecule is not particularly limited, but isobornyl (meth) acrylate having an isobornyl group and a (meth) acryloyl group is more preferable. Further, (meth) acrylate means acrylate or methacrylate.

The ratio of the constitutional unit derived from the monomer having a bicyclo ring structure and the monomer having one olefinic double bond in the molecule in the 100 parts by weight of the copolymer is 10 to 60 parts by weight. If the proportion of the constitutional unit derived from a monomer having a bicyclo ring structure and a monomer having an olefinic double bond in the molecule is less than 10 parts by weight, the resulting adhesive tape deteriorates the adhesive force to the polycarbonate plate and the acrylic plate, The bubble growth at the interface with the polycarbonate plate or the acrylic plate can not be prevented sufficiently. When the proportion of the constitutional unit derived from the monomer having a bicyclo ring structure and one olefinic double bond in the molecule is more than 60 parts by weight, the glass transition temperature of the resulting copolymer becomes high, and the adhesion The adhesion of the tape to the polycarbonate plate and the acrylic plate is lowered and the bubble growth at the interface with the polycarbonate plate or the acrylic plate can not be sufficiently prevented under high temperature conditions.

The ratio of the constitutional unit derived from the monomer having a bicyclo ring structure and the monomer having one olefinic double bond in the molecule in the molecule is preferably 15 to 55 parts by weight and more preferably 20 to 50 parts by weight in 100 parts by weight of the copolymer Do.

The copolymer has a constituent unit derived from a (meth) acrylate monomer having a structure represented by the following general formula (1).

(2)

In the general formula (1), R ¹ represents a hydrogen atom or a methyl group, and R ² represents an alkyl group having 3 to 14 carbon atoms. The hydrogen atom of the alkyl group of R ² may be substituted with a cycloalkyl group.

When the number of carbon atoms of the alkyl group of R ² is 2 or less or 15 or more, the resulting copolymer has a high glass transition temperature. In the pressure-sensitive adhesive tapes produced using the copolymer, the initial wettability of the pressure- The adhesion to the plate is lowered and bubble growth at the interface with the polycarbonate plate or the acrylic plate can not be sufficiently prevented under high temperature conditions. The alkyl group of R < ² > preferably has 4 to 12 carbon atoms.

The hydrogen atom of the alkyl group of R < ² > may be substituted with a cycloalkyl group. The cycloalkyl group is not particularly limited, and examples thereof include a cyclopropyl group, a cyclobutyl group, a cyclopentyl group, a cyclohexyl group, a cycloheptyl group, and a cyclooctyl group.

The (meth) acrylic acid ester monomer having the structure represented by the general formula (1) is not particularly limited and includes, for example, butyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, (Meth) acrylate, isodecyl (meth) acrylate, lauryl (meth) acrylate, isopropyl (meth) acrylate, (Meth) acrylate, isotetradecyl (meth) acrylate, and the like. When the copolymer has a structural unit derived from such a monomer, the resulting pressure-sensitive adhesive tape improves the cohesive strength, initial adhesion, adhesion and the like of the pressure-sensitive adhesive layer in addition to the adhesive force to the polycarbonate plate and the acrylic plate.

Among them, the (meth) acrylate monomer having a structure represented by the general formula (1) is preferably a 2-ethylhexyl (meth) acrylate, an octyl (meth) acrylate (Meth) acrylate monomer and at least one (meth) acrylate monomer selected from the group consisting of methyl (meth) acrylate and butyl (meth) acrylate.

The proportion of the constitutional unit derived from the (meth) acrylate monomer having the structure represented by the general formula (1) in 100 parts by weight of the copolymer is 30 to 90 parts by weight. When the proportion of the constitutional unit derived from the (meth) acrylate monomer having the structure represented by the general formula (1) is less than 30 parts by weight, the resulting pressure-sensitive adhesive tape has a low temperature elastic modulus of the pressure-sensitive adhesive layer and low initial wettability, The adhesion to the polycarbonate plate and the acrylic plate is lowered and the growth of the bubbles at the interface with the polycarbonate plate or the acrylic plate can not be sufficiently prevented under high temperature conditions. If the proportion of the constitutional unit derived from the (meth) acrylic acid ester monomer having the structure represented by the above general formula (1) exceeds 90 parts by weight, the resulting pressure-sensitive adhesive tape has a problem that the cohesive force of the pressure- The proportion of the constitutional unit derived from the monomer having a monocyclic olefinic double bond and the bicyclo ring structure in the molecule in the copolymer is relatively lowered so that the adhesive force of the obtained pressure sensitive adhesive tape to the polycarbonate plate and the acrylic plate .

The proportion of the (meth) acrylic acid ester monomer having the structure represented by the general formula (1) in 100 parts by weight of the copolymer is preferably 50 to 85 parts by weight.

The copolymer may further contain a constituent unit derived from another monomer.

When the copolymer has a constitutional unit derived from the other monomer, the intermolecular interaction of the resulting copolymer increases, and the cohesive force of the pressure-sensitive adhesive layer increases in the pressure-sensitive adhesive tape produced using the copolymer. Further, when the other monomer has a polar group, the polar group and the surface of the polycarbonate plate or the acrylic plate interact with each other, so that the resulting adhesive tape has an increased interfacial adhesion to the pressure-sensitive adhesive layer.

The other monomer is not particularly limited, but monomers having at least one polar group and one olefinic double bond selected from the group consisting of a carboxyl group, hydroxyl group, amide group, amino group, epoxy group, aldehyde group and isocyanate group in the molecule are preferable. Of these other monomers, a monomer having a carboxyl group and an olefinic double bond in the molecule, or a monomer having a hydroxyl group and an olefinic double bond in the molecule is more preferable because the cohesive force of the pressure-sensitive adhesive layer of the resulting pressure-sensitive adhesive tape becomes high.

The monomer having a carboxyl group and one olefinic double bond in the molecule is not particularly limited and examples thereof include (meth) acrylic acid, (meth) acryloyl acetic acid, (meth) acryloyl propionic acid, Unsaturated monocarboxylic acids such as butyric acid, (meth) acryloylpentanoic acid and crotonic acid, and unsaturated dicarboxylic acids such as maleic acid, fumaric acid, citraconic acid, mesaconic acid and itaconic acid.

In the case where the copolymer has a constituent unit derived from a monomer having a carboxyl group and an olefinic double bond in the molecule, it is preferable that a monomer having a carboxyl group and one olefinic double bond in the molecule, which is contained in 100 parts by weight of the copolymer The proportion of the derived constituent unit is preferably 2 parts by weight or less. When the proportion of the structural unit derived from a monomer having a carboxyl group and one olefinic double bond in the molecule exceeds 2 parts by weight, the pressure-sensitive adhesive layer of the pressure-sensitive adhesive tape to be obtained may be a metal thin film containing ITO or the like or a metal oxide- The metal thin film may be easily deteriorated. The proportion of constituent components derived from a monomer having a carboxyl group and a single olefinic double bond in the molecule in the molecule of 100 parts by weight of the copolymer is more preferably 1 part by weight or less and still more preferably 0.5 parts by weight or less.

The copolymer may not have a constituent unit derived from a monomer having a carboxyl group and one olefinic double bond in the molecule.

Further, in general, the acid component in the copolymer contained in the pressure-sensitive adhesive layer causes deterioration of the metal thin film when a metal thin film containing ITO or the like or a metal oxide is used as an adherend. On the other hand, when the copolymer does not contain, for example, an acid component such as a structural unit derived from a monomer having a carboxyl group and a single olefinic double bond in the molecule, a high- It is difficult to obtain a layer.

On the other hand, in the adhesive tape of the present invention, it is preferable that the copolymer has a structural unit derived from a monomer having a bicyclo ring structure and one olefinic double bond in the molecule and a structural unit derived from a monomer having a structure represented by the general formula (1) (Meth) acrylic acid ester monomer, it is possible to provide a pressure-sensitive adhesive layer which is excellent in adhesion, cohesion, initial adhesion, adhesion, and the like even when the copolymer does not contain an acid component, Is high. Therefore, the pressure-sensitive adhesive tape of the present invention can maintain high reliability even under high-temperature conditions, and can suppress the deterioration of the metal thin film containing ITO or the like or a metal oxide.

The monomer having a hydroxyl group and one olefinic double bond in the molecule is not particularly limited, and examples thereof include 2-hydroxyethyl (meth) acrylate, 3-hydroxypropyl (meth) acrylate, Butyl (meth) acrylate, and the like.

When the copolymer has a constituent unit derived from the other monomer, the proportion of the constituent unit derived from the other monomer in 100 parts by weight of the copolymer is not particularly limited, but is preferably 20 parts by weight or less. If the proportion of the constitutional unit derived from the other monomer is more than 20 parts by weight, the resulting pressure-sensitive adhesive tape will have low initial wettability of the pressure-sensitive adhesive layer and poor adhesion to the polycarbonate plate and the acrylic plate, Or the bubble growth at the interface with the acrylic plate can not be prevented sufficiently. It is more preferable that the proportion of the constituent unit derived from the other monomer in 100 parts by weight of the copolymer is 15 parts by weight or less.

The method for producing the copolymer is not particularly limited, and examples thereof include monomers having a bicyclo ring structure and one olefinic double bond in the molecule, (meth) acrylic acid having a structure represented by the general formula (1) A method in which a monomer mixture containing an ester monomer and, if necessary, the above-mentioned other monomer is subjected to radical polymerization in the presence of a polymerization initiator.

The polymerization method is not particularly limited, and conventionally known polymerization methods such as solution polymerization, emulsion polymerization, suspension polymerization and bulk polymerization can be used.

The solvent used in the solution polymerization is not particularly limited, and examples thereof include ethyl acetate, toluene, dimethylsulfoxide, ethanol, acetone, diethyl ether, and the like.

The amount of the solvent used in the solution polymerization is not particularly limited, but the lower limit is preferably 25 parts by weight and the upper limit is preferably 300 parts by weight based on 100 parts by weight of the monomer mixture. When the blending amount of the solvent is less than 25 parts by weight, the molecular weight distribution of the resulting copolymer is widened, and the pressure-sensitive adhesive tape produced using the copolymer lowers the adhesive force to the polycarbonate plate and the acrylic plate and the cohesive force of the pressure- , The bubble growth at the interface with the polycarbonate plate or the acrylic plate can not be sufficiently prevented under high temperature conditions. If the blending amount of the solvent exceeds 300 parts by weight, it may be necessary to prepare the pressure-sensitive adhesive composition using the obtained copolymer and to remove the solvent at the time of manufacturing the pressure-sensitive adhesive tape.

The polymerization initiator is not particularly limited, and examples thereof include persulfates, organic peroxides, and azo compounds. Among them, in the case where a metal thin film containing ITO or the like or a metal oxide is used as an adherend, an azo compound is preferable considering the influence on the metal thin film.

The persulfate is not particularly limited, and examples thereof include potassium persulfate, sodium persulfate, and ammonium persulfate. The organic peroxide is not particularly limited and includes, for example, 1,1-bis (t-hexylperoxy) -3,3,5-trimethylcyclohexane, t-hexylperoxy pivalate, (2-ethylhexanoylperoxy) hexane, t-hexylperoxy-2-ethylhexanoate, t-butylperoxy-2- Ethylhexanoate, t-butylperoxyisobutyrate, t-butylperoxy-3,5,5-trimethylhexanoate, and t-butylperoxylaurate. The azo compound is not particularly limited, and examples thereof include azo compounds such as 2,2'-azobisisobutyronitrile, 2,2'-azobis (2,4-dimethylvaleronitrile), 4,4'-azobis (4-cyanopentanoic acid), 2,2'-azobis (2-methylbutyronitrile), and azobiscyclohexanecarbonitrile.

These polymerization initiators may be used alone or in combination of two or more.

The blending amount of the polymerization initiator is not particularly limited, but is preferably 0.02 to 0.5 parts by weight based on 100 parts by weight of the monomer mixture. If the blending amount of the polymerization initiator is less than 0.02 parts by weight, the polymerization reaction may become insufficient or the polymerization reaction may take a long time. When the blending amount of the polymerization initiator is more than 0.5 parts by weight, the weight average molecular weight of the obtained copolymer may be too low or the molecular weight distribution may be excessively widened. In the case of the adhesive tape produced using the copolymer, And the cohesive force of the adhesive layer and the cohesive force of the pressure-sensitive adhesive layer are lowered and the bubble growth at the interface with the polycarbonate plate or the acrylic plate can not be sufficiently prevented under high temperature conditions.

The weight average molecular weight of the copolymer is not particularly limited, but is preferably 200,000 to 1,500,000. When the weight average molecular weight of the copolymer is less than 200,000, the obtained pressure-sensitive adhesive tape has a problem that the high-temperature elastic modulus of the pressure-sensitive adhesive layer is lowered and the bubble growth at the interface with the polycarbonate plate or the acrylic plate There is a case. When the weight average molecular weight of the copolymer exceeds 1.5 million, the flowability of the copolymer is lowered, and the pressure-sensitive adhesive tape produced using the copolymer lowers the adhesion to the polycarbonate plate and the acrylic plate, There is a case that bubble growth at the interface with the plate or the acrylic plate can not be sufficiently prevented. The weight average molecular weight of the copolymer is more preferably from 300,000 to 1,200,000, and still more preferably from 400,000 to 900,000.

In the present specification, the weight average molecular weight means a value measured by gel permeation chromatography (GPC) in terms of polystyrene conversion. Specifically, for example, the copolymer is diluted 100 times with tetrahydrofuran (THF) to obtain a diluted solution. The diluted solution thus obtained is filtered with a filter. The obtained filtrate is applied to a column (for example, a trade name of 2690 Separations Model ", etc.).

Since the copolymer has a low viscosity, when the pressure-sensitive adhesive layer is formed using the pressure-sensitive adhesive composition containing the copolymer, it is possible to coat the pressure-sensitive adhesive layer well without diluting it with a solvent, and the handling property is excellent. Further, since it can be applied without using a solvent, it is easy to produce a thick pressure-sensitive adhesive layer, and the adhesive force of the pressure-sensitive adhesive layer to the polycarbonate plate and the acrylic plate can be increased. The viscosity of the copolymer is not particularly limited, but it is preferable that the viscosity measured by a B-type viscometer ("B8U-type viscometer", manufactured by Tokyo Kikai Co., Ltd.) at a temperature of 25 ° C is 500 to 100000 Pa · s.

The pressure-sensitive adhesive composition may contain a crosslinking agent in addition to the copolymer.

By containing the crosslinking agent, a crosslinked structure can be formed in the copolymer. The gel fraction of the pressure-sensitive adhesive layer of the obtained pressure-sensitive adhesive tape can be adjusted by suitably adjusting the kind and amount of the crosslinking agent.

The crosslinking agent is not particularly limited, and examples thereof include an isocyanate crosslinking agent, an aziridine crosslinking agent, an epoxy crosslinking agent, and a metal chelate crosslinking agent. Among them, the pressure-sensitive adhesive composition preferably contains at least one crosslinking agent selected from the group consisting of isocyanate-based crosslinking agents and epoxy-based crosslinking agents in view of easily exhibiting performance such as heat resistance and durability.

The isocyanate crosslinking agent is not particularly limited, but an aliphatic isocyanate crosslinking agent is preferred. Of the aliphatic isocyanate-based crosslinking agents, commercially available products include, for example, Coronate HX (manufactured by Nippon Polyurethane Industry Co., Ltd.).

The epoxy cross-linking agent is not particularly limited, but an aliphatic epoxy cross-linking agent is preferred. Among the above-mentioned aliphatic epoxy cross-linking agents, commercially available products include, for example, Denacol EX212 and Denacol EX214 (both manufactured by Nagase Chemtech).

The blending amount of the crosslinking agent is not particularly limited, but is preferably 0.1 to 10 parts by weight based on 100 parts by weight of the copolymer. If the blending amount of the crosslinking agent is less than 0.1 part by weight, crosslinking of the copolymer becomes insufficient, and the resulting pressure-sensitive adhesive tape may have poor cohesive strength and poor workability of the pressure-sensitive adhesive layer. In addition, The bubble growth at the interface between the substrate and the substrate can not be sufficiently prevented. If the blending amount of the cross-linking agent exceeds 10 parts by weight, the resulting adhesive tape may deteriorate the adhesive strength and initial adhesion to the polycarbonate plate and the acrylic plate. The blending amount of the crosslinking agent is more preferably 0.3 to 3.0 parts by weight based on 100 parts by weight of the copolymer.

The pressure-sensitive adhesive composition may further contain a tackifier resin.

The tackifier resin is not particularly limited, and examples thereof include a xylene resin, a phenol resin, a rosin resin, a terpene resin and the like. These tackifier resins may be used alone or in combination of two or more. Among them, xylene resin is preferable and alkylphenol reactant of xylene resin is more preferable. It is preferable to use a hydrogenated resin as the tackifier resin. By using such a resin, the transparency of the adhesive tape can be increased.

The pressure-sensitive adhesive composition may further contain a silane coupling agent. By containing the silane coupling agent, the adhesion property of the resulting adhesive tape to the polycarbonate plate and the acrylic plate can be improved.

The silane coupling agent is not particularly limited and includes, for example, vinyltrimethoxysilane, vinyltriethoxysilane, methacryloxypropyltrimethoxysilane,? -Methacryloxypropylmethyldimethoxysilane,? -Glycidyl Glycidoxypropylmethyldimethoxysilane, γ-glycidoxypropylmethyldimethoxysilane, γ-glycidoxypropylmethyldiethoxysilane, 2- (3,4-epoxycyclohexyl) ethyltrimethoxysilane, γ-aminopropyl Aminopropyltriethoxysilane,? -Aminopropyltrimethylmethoxysilane, N- (2-aminoethyl) 3-aminopropyltriethoxysilane, N- (2-aminoethyl) Aminopropylmethyldimethoxysilane,? -Mercaptopropyltrimethoxysilane,? -Mercaptopropyltriethoxysilane, mercaptobutyltrimethoxysilane,? -Mercaptopropylmethyldimethoxysilane, and the like.

The pressure-sensitive adhesive composition may further contain conventionally known additives as required.

The additive is not particularly limited as long as it does not impair the transparency of the obtained pressure-sensitive adhesive tape, and examples thereof include a filler and an antioxidant.

The method for producing the pressure-sensitive adhesive composition is not particularly limited, and for example, a method of mixing the copolymer and, if necessary, the crosslinking agent, the tackifier resin, the silane coupling agent, have.

The pressure-sensitive adhesive layer preferably has a shear storage modulus (G ') at a measurement frequency of 10 Hz of 1 x 10 ⁵ to 1 x 10 ⁷ Pa at 20 캜 and 3 x 10 ⁴ to 1 x 10 ⁵ Pa at 85 캜 . When the shear storage elastic modulus (G ') is less than 1 x 10 < ⁵ > Pa at 20 DEG C or less than 3 x 10 < ⁴ > Pa at 85 DEG C, the deformation of the pressure sensitive adhesive layer against stress increases, There is a case. When the shear storage elastic modulus (G ') exceeds 1 x 10 < ⁷ > Pa at 20 DEG C or exceeds 1 x 10 < ⁵ > Pa at 85 DEG C, the initial wettability of the pressure- The adhesion to the acrylic plate is lowered and the lifting separation occurring at the interface with the polycarbonate plate or the acrylic plate under high temperature conditions can not be sufficiently suppressed.

It is preferable that the pressure-sensitive adhesive layer has a shear storage modulus (G ') at a measurement frequency of 10 Hz of 1.2 x 10 ⁵ to 8 x 10 ⁶ Pa at 20 캜 and 3.2 x 10 ⁴ to 9 x 10 ⁴ Pa at 85 캜 and, at ^{20 ℃ 1.4 × 10 5 ~ 6} × 10 6 ㎩, more preferably from ^{85 ℃ 3.4 × 10 4 ~ 8} × 10 4 ㎩.

In the present specification, the shear storage elastic modulus (G ') at a measurement frequency of 10 Hz is measured using a dynamic viscoelasticity measuring device such as " DVA-200 " manufactured by Haitian Instrumentation Control Co., Means the shear storage modulus (G ') measured in ° C / min.

The pressure-sensitive adhesive layer has a maximum point at an acidity (tan?) Obtained by dividing the shear loss elastic modulus (G ") at the same measurement temperature by the shear storage modulus (G ') in the temperature range of -25 to 25 ° C desirable.

For example, when the pressure-sensitive adhesive layer does not have a maximum point on the acid uniformity (tan?) In the temperature region and the acidity (tan?) Of the pressure-sensitive adhesive layer exceeds 25 占 폚, The initial wettability is lowered and the adhesion to the polycarbonate plate or the acrylic plate is lowered so that the lifting peeling at the interface with the polycarbonate plate or the acrylic plate under high temperature conditions can not be suppressed. For example, when the pressure-sensitive adhesive layer does not have a maximum point in the acidity (tan?) In the temperature region and the acidity (tan?) Of the pressure-sensitive adhesive layer is less than -25 占 폚, The cutting workability of the adhesive tape is deteriorated, and the pressure-sensitive adhesive at the cut end portion adheres to the cutting edge to interfere with the processing.

In the present specification, "the maximum value of the acidity (tan?) Obtained by dividing the shear loss elastic modulus (G") at the same measurement temperature by the shear storage modulus (G ') in the temperature range of -25 to 25 ° C Quot; means that the shear modulus of elasticity (G '') is measured at -25 to 25 DEG C at a frequency of 10 Hz and a temperature rising rate of 5 DEG C / min using a dynamic viscoelasticity measuring device such as DVA- ) And a shear storage elastic modulus (G ') are measured, and graphs are prepared assuming that the horizontal axis represents the temperature and the vertical axis represents the acid uniformity (tan delta).

The gel fraction of the pressure-sensitive adhesive layer is not particularly limited and can be suitably adjusted in accordance with the use of the pressure-sensitive adhesive tape, because the lifting peeling occurring at the interface with the polycarbonate plate or the acrylic plate under high temperature conditions can be suppressed, Among them, it is preferably 30 to 95% by weight. If the gel fraction of the pressure-sensitive adhesive layer is less than 30% by weight, the workability of the pressure-sensitive adhesive tape may be deteriorated. If the gel fraction of the pressure-sensitive adhesive layer exceeds 95% by weight, the initial wettability of the pressure-sensitive adhesive layer of the pressure-sensitive adhesive tape is lowered and the adhesion to the polycarbonate plate and the acrylic plate is lowered, The bubble growth at the interface can not be sufficiently prevented. The gel fraction of the pressure-sensitive adhesive layer is more preferably 40 to 90% by weight.

The gel fraction can be measured by the following method.

First, the adhesive tape of the present invention is cut into a flat rectangular shape of 50 mm x 25 mm to produce a test piece. The obtained test piece was immersed in ethyl acetate at 23 占 폚 for 24 hours, and then the test piece was taken out of ethyl acetate through a 200-mesh stainless steel mesh and dried at 110 占 폚 for 1 hour. Then, the weight of the dried test piece is measured, and the gel fraction is calculated using the following formula (1). The release tape or the release film is not laminated on the adhesive tape used for the test piece.

Gel fraction (% by weight) = 100 x (W ₂ - W ₀ ) / (W ₁ - W ₀ )

In the formula (1), W ₀ represents the weight of the base material, W ₁ represents the weight of the test piece before immersion, and W ₂ represents the weight of the test piece after immersion and drying. When the adhesive tape has no substrate, W ₀ = 0.

The thickness of the pressure-sensitive adhesive layer is not particularly limited, but is preferably 20 to 500 탆. If the thickness of the pressure-sensitive adhesive layer is less than 20 占 퐉, the pressure-sensitive adhesive tape has a low adhesive force to the polycarbonate plate and the acrylic plate and can not sufficiently inhibit the growth of bubbles at the interface with the polycarbonate plate or the acrylic plate under high temperature conditions There is a case. If the thickness of the pressure-sensitive adhesive layer exceeds 500 m, the pressure-sensitive adhesive component may leak out, resulting in deterioration in handling properties. The thickness of the pressure-sensitive adhesive layer is more preferably 20 to 300 占 퐉.

The adhesive tape of the present invention has a total light transmittance of 90% or more and a haze value of 1% or less in the visible light wavelength region. When the total light transmittance in the visible light wavelength region is less than 90% or the haze value is more than 1%, the transparency of the pressure-sensitive adhesive tape lowers and it is difficult to apply it to optical applications.

The adhesive tape of the present invention is preferably an adhesive tape for sticking to a polycarbonate plate or an acrylic plate.

It is also preferable that the adhesive tape of the present invention has a 180 DEG peel force against a polycarbonate plate or an acrylic plate at a rate of 3 N / 25 mm or more at a peeling speed of 0.3 mm / min. If the peeling force is less than 3 N / 25 mm, the pressure-sensitive adhesive tape may not be able to sufficiently prevent lifting peeling occurring at the interface with the polycarbonate plate or the acrylic plate under high temperature conditions. In addition, the present inventors think that the peeling speed of 0.3 mm / min is a suitable rate for evaluating the progress of lifting peeling when a polycarbonate plate or an acrylic plate is used as an adherend.

The pressure-sensitive adhesive tape of the present invention preferably has a 180 DEG peel force on a polycarbonate plate or an acrylic plate at a peel rate of 0.3 mm / min, more preferably at least 3.2 N / 25 mm, and still more preferably at least 3.4 N / 25 mm.

In the present specification, the 180 占 peeling force for a polycarbonate plate or an acrylic plate at a peeling speed of 0.3 mm / min means a value calculated by the following method.

First, the adhesive tape is cut to have a planar shape of 25 mm x 100 mm. One of the release type polyethylene terephthalate films of the cut adhesive tape is peeled off to expose the pressure-sensitive adhesive layer. Subsequently, a polyethylene terephthalate film having a thickness of 50 占 퐉 is bonded to the exposed surface of the adhesive tape. The other side of the pressure-sensitive adhesive tape was peeled off to expose the pressure-sensitive adhesive layer, and the exposed side of the pressure-sensitive adhesive tape on the polycarbonate plate or the acrylic plate was pressed at a speed of 300 mm / min And a polycarbonate plate or an acrylic plate is adhered to the adhesive tape and left at 23 占 폚 for 24 hours to prepare a test sample.

The obtained test sample was subjected to a tensile test in the direction of 180 DEG at a peeling speed of 0.3 mm / min. The obtained value was measured at 180 DEG peel force (N / mm < 2 >) against a polycarbonate plate or acrylic plate at a peeling rate of 0.3 mm / 25 mm).

The adhesive tape of the present invention may be of a non-support type having no substrate, or may be a support type having a pressure-sensitive adhesive layer formed on both surfaces of the substrate.

The substrate is not particularly limited as long as it is a substrate having transparency, and examples thereof include acrylic resin, polyolefin, polycarbonate, polyvinyl chloride, acrylo 2-tolylbutadiene styrene (ABS) resin, polyethylene terephthalate (PET) A sheet made of a transparent resin such as urethane or polyimide, a sheet having a net-like structure, a sheet having a hole, and the like.

The thickness of the base material is not particularly limited, but is preferably 2 to 200 占 퐉. If the thickness of the base material is less than 2 탆, the strength of the obtained pressure-sensitive adhesive tape may be insufficient, resulting in tearing or difficulty in handling. If the thickness of the base material exceeds 200 占 퐉, the rigidity of the base material is excessively strong, and the followability of the step of the obtained pressure-sensitive adhesive tape may be deteriorated. The thickness of the substrate is more preferably 5 to 100 탆.

The adhesive tape of the present invention may have a release paper or a release film laminated on the pressure-sensitive adhesive layer.

The releasing paper or release film is not particularly limited and may be, for example, a release film obtained by subjecting a synthetic resin film made of a polyester resin, a polyethylene resin, a polypropylene resin, polyvinyl chloride, nylon or the like to a release process, And releasing paper obtained by forming a release layer on a base paper having a high surface smoothness such as cloth or glaze paper.

The thickness of the releasing paper or release film is not particularly limited, but is preferably 12 to 125 占 퐉. If the thickness is out of the above range, the cutting workability of the pressure-sensitive adhesive tape may be deteriorated. The thickness of the release paper or release film is more preferably 20 to 100 占 퐉. The center line average roughness (Ra) of the releasing paper or release film is not particularly limited, but is preferably 0.2 탆 or less.

The method for producing the pressure sensitive adhesive tape of the present invention is not particularly limited. For example, as a method for producing a pressure sensitive adhesive tape of a non-support type, a pressure sensitive adhesive layer is formed by applying the pressure sensitive adhesive composition onto a releasing treated surface of a release paper or release film , A method of laminating a newly prepared releasing paper or release film on the resulting pressure-sensitive adhesive layer so that the release-treated surface faces the pressure-sensitive adhesive layer to obtain a laminate, and then pressing the resulting laminate with a rubber roller or the like .

The use of the pressure-sensitive adhesive tape of the present invention is not particularly limited. However, when an image display apparatus such as a cellular phone or a portable information terminal is manufactured, a protective plate for protecting the surface made of a polycarbonate plate or an acrylic plate is used as a display panel, (Refer to Fig. 5). It is also possible to use the display panel or the touch panel for bonding with the surface of a support made of a polycarbonate plate or an acrylic plate.

INDUSTRIAL APPLICABILITY The adhesive tape of the present invention can be preferably applied to optical applications having high transparency and requiring high transparency such as bonding to a display panel or a touch panel. In addition, since the polycarbonate plate and the acrylic plate are easy to absorb moisture, outgas generated under high temperature conditions is apt to cause lifting peeling at the interface with the pressure-sensitive adhesive layer. By using the pressure-sensitive adhesive tape of the present invention, The same lifting exfoliation can be effectively suppressed.

A laminate obtained by bonding a polycarbonate plate or an acrylic plate to a transparent electrode through the adhesive tape of the present invention is also one of the present invention.

The polycarbonate plate or the acrylic plate is not particularly limited but is preferably a polycarbonate plate or an acrylic plate used for an image display apparatus or the like and is preferably a polycarbonate used as a protective plate for protecting the surface of an image display apparatus or the like Plate or an acrylic plate.

As the transparent electrode, for example, an ITO electrode and the like can be given.

The laminate of the present invention is not particularly limited as long as the polycarbonate plate or the acrylic plate is pasted to the transparent electrode through the adhesive tape of the present invention, and for example, a laminate used for an image display apparatus can be mentioned.

The image display apparatus having the laminate of the present invention is also one of the present invention.

Examples of the image display device of the present invention include a resistive touch panel, a touch panel such as a capacitive touch panel, and the like.

The resistive film touch panel has, in this order, a protective plate made of, for example, a polycarbonate plate or an acrylic plate, an upper transparent electrode, a spacer, and a support having a lower transparent electrode. An example of such a resistive film touch panel is shown in Fig.

In the resistive film type touch panel shown in Fig. 3, the protective plate 1 made of a polycarbonate plate or an acrylic plate is bonded to the upper transparent electrode 3 through the adhesive tape 2 of the present invention. The support 7 and the lower transparent electrode 5 are bonded to each other through the adhesive tape 6 of the present invention. The support 7 and the lower transparent electrode 5 may be bonded by the adhesive tape of the present invention or by an adhesive tape other than the adhesive tape of the present invention. The support 7 and the lower transparent electrode 5 may be laminated by a method other than an adhesive tape. In the resistive film type touch panel shown in Fig. 3, the adhesive tape of the present invention is a double-sided adhesive tape.

The capacitive touch panel has, for example, a protective plate made of a polycarbonate plate or an acrylic plate, a glass plate on which an ITO film is formed on the front and back, and a support. An example of such a capacitive touch panel is shown in Fig.

4, a protective plate 8 made of a polycarbonate plate or an acrylic plate and a glass plate (a protective film) 8 on which the ITO films 10 and 12 are formed on the front and back sides, respectively, through the adhesive tape 9 of the present invention 11). Further, a glass plate (opposite surface) on which an ITO film is formed on the front and back surfaces is bonded to the support member 14 through the adhesive tape 13 of the present invention. The support 14 and the glass plate on which the ITO film is formed on the front and back surfaces may be bonded by the adhesive tape of the present invention or may be bonded by an adhesive tape other than the adhesive tape of the present invention. The glass plate on which the support 14 and the ITO film are formed on the front and back surfaces may be laminated by a method other than the adhesive tape. Further, in the capacitive touch panel shown in Fig. 4, the adhesive tape of the present invention is a double-sided adhesive tape.

According to the present invention, there is provided an adhesive tape having high transparency, excellent adhesion to a polycarbonate plate and an acrylic plate, and capable of suppressing lifting peeling occurring at an interface with a polycarbonate plate or an acrylic plate even under high temperature conditions . According to the present invention, a laminate and an image display device manufactured using the adhesive tape can be provided.

Fig. 1 is a photograph of a test sample produced using the double-faced pressure-sensitive adhesive tape obtained in Example 1 in the evaluation of the bubble generation state.
2 is a photograph of a test sample produced using the double-faced pressure-sensitive adhesive tape obtained in Comparative Example 1 in the evaluation of the bubble generation state.
3 (a) and 3 (b) are a cross-sectional view and a perspective view that schematically show one example in which a protective plate made of a polycarbonate plate or an acrylic plate is attached to a transparent electrode through the adhesive tape of the present invention.
4 (a) and 4 (b) are a cross-sectional view and a perspective view that schematically show an example of a case where a protective plate made of a polycarbonate plate or an acrylic plate is attached to a transparent electrode through the adhesive tape of the present invention.
5 is a cross-sectional view schematically showing an example of a case where a protective plate is attached to the surface of an image display device using the adhesive tape of the present invention.

Hereinafter, embodiments of the present invention will be described in more detail with reference to examples, but the present invention is not limited to these examples.

(Example 1)

(1) Production of double-sided adhesive tape

89.3 parts by weight of 2-ethylhexyl acrylate, 10 parts by weight of isobornyl acrylate, 0.5 part by weight of acrylic acid, 0.2 part by weight of 2-hydroxyethyl acrylate, and 100 parts by weight of these monomers were mixed in a reactor equipped with a stirrer, , 100 parts by weight of ethyl acetate was added, and after nitrogen replacement, the reactor was heated to initiate reflux. Next, 0.2 part by weight of t-hexyl peroxy pivalate as a polymerization initiator was diluted with 5 parts by weight of ethyl acetate based on 100 parts by weight of the monomer, and the resulting polymerization initiator solution was added dropwise to the reactor over 2 hours. Thereafter, the solution was refluxed at 70 캜 for 8 hours from the start of the addition of the polymerization initiator to obtain an acrylic copolymer solution having a solid content of 50%.

IR (Thermo Fisher Scientific Co., Ltd.), GC-MS apparatus (manufactured by Nippon Denki Co., Ltd., Q-1000GC), Pyrolysis apparatus (Double Shot Pyrolizer manufactured by Frontier Laboratories Co., Ltd.) (Weight%) of the constituent units derived from each monomer constituting the acrylic copolymer were measured using a spectrophotometer (NICOLET6700) and NMR (JNM-ECA400, manufactured by NIHON Electronics Co., Ltd.). The ratio (% by weight) of the constituent units obtained is shown in Table 1.

The obtained acrylic copolymer had a weight average molecular weight of about 500,000 as measured by a GPC method using a "2690 Separations Model" manufactured by Waters Corporation as a column in terms of polystyrene.

0.5 part by weight of Coronate HX (manufactured by Nippon Polyurethane Industry Co., Ltd.) as a crosslinking agent was added to 100 parts by weight of the obtained acrylic copolymer and stirred to obtain a pressure-sensitive adhesive composition. The pressure-sensitive adhesive composition thus obtained was applied to the release-treated surface of the release-type polyethylene terephthalate film to form a pressure-sensitive adhesive layer, and a newly prepared release-type polyethylene terephthalate film was superimposed on the pressure-sensitive adhesive layer so that the release- To obtain a laminate. The resulting laminate was pressed with a rubber roller to obtain a double-faced pressure-sensitive adhesive tape in which a releasable polyethylene terephthalate film was attached to both surfaces.

(2) Measurement of gel fraction

A double-sided pressure-sensitive adhesive tape was cut into a flat rectangular shape of 50 mm x 25 mm to prepare a test piece having no release paper or release film laminated, and the weight W ₁ of the produced test piece was measured. The test piece was immersed in ethyl acetate at 23 DEG C for 24 hours, and then the test piece was taken out of ethyl acetate through a 200-mesh stainless steel mesh and dried at 110 DEG C for 1 hour. The weight W ₂ of the test piece after drying was measured, and the gel fraction was calculated by the formula (1).

(3) Measurement of total light transmittance and haze value in the visible light wavelength region

A double-sided pressure-sensitive adhesive tape was laminated on a slide glass (trade name: "S-1214", manufactured by MATSUNAMI) to prepare a test piece having a pressure-sensitive adhesive layer / slide glass layer structure. The total light transmittance and the total light transmittance The haze value (%) was measured using a haze meter (automatic haze meter " TC-HIIIDPK ", manufactured by Tokyo Electron Co., Ltd.).

(4) Measurement of adhesive force

The double-faced pressure-sensitive adhesive tape was cut to have a planar shape of 25 mm x 100 mm. One of the release type polyethylene terephthalate films of the cut double-sided adhesive tape was peeled off to expose the pressure-sensitive adhesive layer. Then, the exposed side of the double-faced adhesive tape was bonded onto the polyethylene terephthalate film. Further, the other one-side releasable polyethylene terephthalate film of the double-sided pressure-sensitive adhesive tape is peeled to expose the pressure-sensitive adhesive layer, and the exposed surface of the double-faced pressure-sensitive adhesive tape is stuck on the polycarbonate plate (PC plate) A double-faced pressure-sensitive adhesive tape and a polyethylene terephthalate film were stacked in this order to obtain a laminated sample. Thereafter, a 2.0 kg rubber roller was placed on the polyethylene terephthalate film of the obtained laminated sample, and a polycarbonate plate (PC plate) and a double-faced adhesive tape were laminated by making one round trip of the rubber roller at a speed of 300 mm / And then left at 23 DEG C for 20 minutes to prepare a test sample.

A test sample was similarly prepared using an acrylic plate instead of the polycarbonate plate (PC plate).

The obtained test sample was subjected to a tensile test in the direction of 180 DEG at a peeling speed of 300 mm / min according to JIS Z 0237 to measure the adhesive force (N / 25 mm).

(5) Bubbling state (foam resistance test)

The double-sided pressure-sensitive adhesive tape was cut to have a planar shape of 45 mm x 60 mm. One of the release type polyethylene terephthalate films of the cut double-sided adhesive tape was peeled off to expose the pressure-sensitive adhesive layer. Then, the exposed surface of the double-sided adhesive tape was bonded onto a polyethylene terephthalate film having a thickness of 0.5 mm. Further, the other one-side releasable polyethylene terephthalate film of the double-faced pressure-sensitive adhesive tape was peeled off to expose the pressure-sensitive adhesive layer, and the exposed face of the double-faced pressure-sensitive adhesive tape on the polycarbonate plate (PC plate) A laminated sample in which a double-faced pressure-sensitive adhesive tape and a polyethylene terephthalate film were laminated in this order on a polycarbonate plate (PC plate) was obtained. Thereafter, the resultant laminated sample was stopped for 500 hours under conditions of a temperature of 85 캜, a temperature of 60 캜 and a relative humidity (RH) of 90% to obtain a test sample. The state of bubble formation at the bonding interface of the obtained test sample was visually observed.

A case where no bubble having a size of 0.01 mm or more was observed at all, a case where 1 to 5 bubbles having a size of 0.01 mm or more was observed per one test sample was defined as " The case where six or more samples were observed per one test sample was evaluated as " x ", and the state of bubble formation was evaluated.

1 shows a photograph of a test sample of Example 1 in which no bubbles having a size of 0.01 mm or more were observed at all and FIG. 2 shows a photograph of a test sample of Comparative Example 1 in which six bubbles having a size of 0.01 mm or more were observed .

(Examples 2 to 15 and Comparative Examples 1 to 6)

A double-faced pressure-sensitive adhesive tape was produced in the same manner as in Example 1 except that an acrylic copolymer having a proportion (weight%) of constituent units shown in Table 1 or 2 was obtained by changing the monomer composition of the acrylic copolymer, Respectively.

(Examples 16 to 21 and Comparative Examples 7 to 10)

(1) Production of double-sided adhesive tape

A double-faced pressure-sensitive adhesive tape was obtained in the same manner as in Example 1, except that the monomer composition of the acrylic copolymer and the addition amount of the crosslinking agent were changed as shown in Table 3.

(2) Measurement of gel fraction

The gel fraction was calculated in the same manner as in Example 1.

(3) Measurement of total light transmittance and haze value in the visible light wavelength region

The total light transmittance and the haze value in the visible light wavelength region were measured in the same manner as in Example 1. [

(4) Measurement of 180 ° peel force on polycarbonate plate or acrylic plate

The double-faced pressure-sensitive adhesive tape was cut to have a planar shape of 25 mm x 100 mm. One of the release type polyethylene terephthalate films of the cut double-sided adhesive tape was peeled off to expose the pressure-sensitive adhesive layer. Then, a polyethylene terephthalate film having a thickness of 50 占 퐉 was bonded to the exposed surface of the double-sided adhesive tape. Further, the other one-side release polyethylene terephthalate film of the double-sided pressure-sensitive adhesive tape was peeled off to expose the pressure-sensitive adhesive layer, and the exposed surface of the pressure-sensitive adhesive tape on the polycarbonate plate or the acrylic plate was coated with a rubber roller of 2.0 kg / A polycarbonate plate or an acrylic plate and a double-faced adhesive tape were laminated and allowed to stand at 23 占 폚 for 24 hours to prepare a test sample.

The obtained test sample was subjected to a tensile test in the direction of 180 DEG at a peeling rate of 0.3 mm / min and the 180 DEG peel force (N / 25 mm) against the polycarbonate plate or acrylic plate at the peeling rate of 0.3 mm / Were measured.

(5) Measurement of shear modulus of the pressure-sensitive adhesive layer

The double-faced pressure-sensitive adhesive tape was superimposed to obtain a double-faced pressure-sensitive adhesive tape having a thickness of 1 mm. The front end storage elastic modulus (G ') of the obtained double-sided adhesive tape at 20 ° C and 85 ° C was measured at a frequency of 10 Hz and a heating rate of 5 ° C / min by a dynamic viscoelasticity measuring apparatus (DVA-200, Respectively. The shear modulus of elasticity (G '') and the shear modulus of elasticity (G ') at -25 to 25 ° C were measured by a dynamic viscoelasticity measuring device (DVA-200, A graph was prepared with the horizontal axis as the temperature and the vertical axis as the acid flatness (tan?) At 5 占 폚 / min, and it was judged whether or not the maximum points were within the range of -25 to 25 占 폚.

In Table 3, when the maximum point is within the range of -25 to 25 ° C, the temperature is described, and when there is no maximum point, "no" is described.

(6) Bubbling state (foam resistance test)

The double-sided pressure-sensitive adhesive tape was cut to have a planar shape of 45 mm x 60 mm. One of the release type polyethylene terephthalate films of the cut double-sided adhesive tape was peeled off to expose the pressure-sensitive adhesive layer. Then, a polyethylene terephthalate film having a thickness of 0.5 mm was bonded to the exposed surface of the double-faced pressure-sensitive adhesive tape. Further, the other one-side releasable polyethylene terephthalate film of the double-sided pressure-sensitive adhesive tape was peeled off to expose the pressure-sensitive adhesive layer, and the exposed side of the pressure-sensitive adhesive tape on a polycarbonate plate or an acrylic plate having a planar shape of 2.0 mm in thickness, , A polycarbonate plate or an acrylic plate and a double-faced adhesive tape were bonded to each other and treated in an autoclave at 60 占 폚 and 0.5 MPa for 20 minutes to prepare test samples.

With respect to the obtained test sample, the polycarbonate plate and the acrylic plate were kept still at a temperature of 85 占 폚 or at a temperature of 60 占 폚 and a relative humidity (RH) of 90% for 500 hours, And observed with naked eyes.

A case where no bubble having a size of 0.01 mm or more was observed at all, a case where one bubble with a size of 0.01 mm or more was observed per one test sample was defined as "Quot;, and " x " when six or more bubbles having a size of 0.01 mm or more were observed per one test sample were evaluated.

(7) Cutting workability test (state of double-sided adhesive tape section)

The double-sided pressure-sensitive adhesive tape was subjected to a punching operation 40 times using a cutter blade, the blade contamination caused by the attachment of the pressure-sensitive adhesive to the cutter blade, and the coving webbing phenomenon of the pressure-

The case where the coved webbing phenomenon of the pressure-sensitive adhesive was not observed was evaluated as "? &Quot;, the case where blade contamination was observed but the coved webbing phenomenon was not observed was indicated as " Was observed and a coving webbing phenomenon was also observed was evaluated as " x ", and the cutting workability was evaluated.

Industrial availability

According to the present invention, there is provided an adhesive tape having high transparency, excellent adhesion to a polycarbonate plate and an acrylic plate, and capable of suppressing lifting peeling occurring at an interface with a polycarbonate plate or an acrylic plate even under high temperature conditions . According to the present invention, a laminate and an image display device manufactured using the adhesive tape can be provided.

1: Shield plate
2: Adhesive tape
3: upper transparent electrode
4: Spacer
5: Lower transparent electrode
6: Adhesive tape
7: Support
8: Shield plate
9: Adhesive tape
10: ITO film
11: Glass plate
12: ITO film
13: Adhesive tape
14: Support
15: Shield plate
16: Adhesive tape
17: Image display device

Claims (17)

A pressure-sensitive adhesive tape having a pressure-sensitive adhesive layer comprising a pressure-sensitive adhesive composition containing a copolymer,
The copolymer is a copolymer comprising a constituent unit derived from a monomer having a bicyclo ring structure and one olefinic double bond in a molecule and a constituent unit derived from a (meth) acrylate monomer having a structure represented by the following general formula (1) , A structural unit derived from a monomer having a hydroxyl group and one olefinic double bond in the molecule,
The ratio of the constitutional unit derived from the monomer having a bicyclo ring structure and one olefinic double bond in the molecule in the 100 parts by weight of the copolymer is not less than 15 parts by weight and not more than 55 parts by weight,
The proportion of the constitutional unit derived from the (meth) acrylic acid ester monomer having the structure represented by the general formula (1) in 100 parts by weight of the copolymer is 30 parts by weight or more and less than 85 parts by weight,
The ratio of the constitutional unit derived from a monomer having a hydroxyl group and an olefinic double bond in the molecule in the molecule of 100 parts by weight of the copolymer is 0 to 20 parts by weight,
A test piece having a pressure-sensitive adhesive layer / slide glass layer structure produced by sticking an adhesive tape to a slide glass was measured for a total light transmittance of 90% or more in a visible light wavelength range measured with a haze meter and a haze value of 1 % Or less.
[Chemical Formula 1]

In the general formula (1), R ¹ represents a hydrogen atom or a methyl group, and R ² represents an alkyl group having 3 to 14 carbon atoms. The hydrogen atom of the alkyl group of R ² may be substituted with a cycloalkyl group. The method according to claim 1,
Wherein the monomer having a bicyclo ring structure and one olefinic double bond in the molecule is a monomer having an isobornyl group. 3. The method according to claim 1 or 2,
Wherein the monomer having a bicyclo ring structure and one olefinic double bond in the molecule is a monomer having a (meth) acryloyl group. 3. The method according to claim 1 or 2,
The (meth) acrylic acid ester monomer having a structure represented by the general formula (1) is at least one (meth) acrylate monomer selected from the group consisting of 2-ethylhexyl (meth) acrylate, octyl (meth) acrylate and butyl Methacrylic acid ester monomer. 3. The method according to claim 1 or 2,
The copolymer is further characterized by having a constituent unit derived from a monomer having at least one polar group and one olefinic double bond selected from the group consisting of a carboxyl group, an amide group, an amino group, an epoxy group, an aldehyde group and an isocyanate group in the molecule . 3. The method according to claim 1 or 2,
Wherein the copolymer has a weight average molecular weight of 200,000 to 1,500,000. 3. The method according to claim 1 or 2,
Wherein the pressure-sensitive adhesive composition further contains at least one crosslinking agent selected from the group consisting of an isocyanate-based crosslinking agent and an epoxy-based crosslinking agent. 8. The method of claim 7,
Wherein the isocyanate crosslinking agent and the epoxy crosslinking agent are an aliphatic isocyanate crosslinking agent and an aliphatic epoxy crosslinking agent, respectively. 3. The method according to claim 1 or 2,
The pressure-sensitive adhesive layer had a shear storage modulus (G ') at a measurement frequency of 10 Hz of 1 x 10 ⁵ to 1 x 10 ⁷ Pa at 20 캜, 3 x 10 ⁴ to 1 x 10 ⁵ Pa at 85 캜, (T) obtained by dividing the shear modulus of elasticity (G '') at the same measurement temperature by the shear storage modulus (G ') in the temperature range of 25 ° C to 25 ° C. 3. The method according to claim 1 or 2,
Wherein the pressure-sensitive adhesive layer has a gel fraction of 30 to 95% by weight. 3. The method according to claim 1 or 2,
Wherein the pressure-sensitive adhesive layer has a thickness of 20 to 500 占 퐉. 3. The method according to claim 1 or 2,
Wherein the adhesive tape is attached to a polycarbonate plate or an acrylic plate. 13. The method of claim 12,
Wherein the 180 ° peel force on the polycarbonate plate or the acrylic plate is 3 N / 25 mm or more at a peeling rate of 0.3 mm / min. 6. The method of claim 5,
Wherein the pressure-sensitive adhesive composition further contains at least one crosslinking agent selected from the group consisting of an isocyanate-based crosslinking agent and an epoxy-based crosslinking agent. A laminate obtained by bonding a polycarbonate plate or an acrylic plate to a transparent electrode through the adhesive tape according to claim 1 or 2. 16. The method of claim 15,
Wherein the polycarbonate plate or the acrylic plate is a protective plate for protecting the surface of the image display device. An image display apparatus having the laminate according to claim 16.

Images