TWI534223B - Adhesive, adhesive sheet and display - Google Patents

Description

Adhesives, adhesive sheets and displays

This invention relates to adhesives. Further, it relates to an adhesive sheet and a display formed using the adhesive.

With the rapid advancement of electronic technology in recent years, various flat panel displays (FPDs) such as liquid crystal display (LCD), plasma display (PDP), rear projection display (RPJ), EL display, and light emitting diode display have been widely used as display devices. use. In such a display device, various films such as an antireflection film for preventing reflection by an external light source and a protective film (protective film) for preventing surface scratching of the display device are generally used. For example, a polarizing film or a retardation film is used for the member for liquid crystal elements used in the LCD.

Moreover, the FPD is also used as an input device such as a touch screen. In the touch screen, a protective film, an anti-reflection film, a transparent electrode film, or the like is usually used. These films are typically pasted using an adhesive (also known as a "pressure-sensitive adhesive").

For adhesives used in touch screen applications, in addition to adhesiveness and transparency, it is also required that the adhesive layer does not generate bubbles (foam resistance) and adheres when used in a high-temperature and high-humidity environment. The film does not float or peel The separation (resistance to peeling), the adhesive layer is not white (non-whitening), and the properties of the transparent electrode are not corroded (non-corrosive). Further, since there is a step difference due to a line on the substrate on the transparent electrode, it is necessary to have a property of embedding the step (step difference followability) with the adhesive layer when the adhesive sheet is adhered to the transparent electrode. .

The touch screen is usually formed on the basis of an LCD, and an adhesive is used to adhere the polarizing plate to the liquid crystal element. The adhesive for a polarizing plate needs to have a performance that the polarizing plate does not peel off from the liquid crystal element or float when used in a severe environment of high temperature and high humidity, and does not expect to leak liquid crystal elements. The performance of light (non-light leakage). The reason why the light leakage phenomenon occurs is that when used in a high-temperature and high-humidity environment, the stress due to the dimensional change of the contraction or expansion of the polarizing plate is not buffered in the adhesive layer, thereby retaining the residual stress originating from the polarizing plate. reason.

Further, since the touch screen is used in a portable information terminal such as a smart phone, it is also important to consider the impact resistance such as dropping. Therefore, a transparent plastic film such as polycarbonate (PC), polymethyl methacrylate (PMMA), or cycloolefin (COP) is usually used for the surface layer of the touch panel. However, since the plastic having high transparency is hard and has poor flexibility, it is necessary to obtain a desired flexibility, workability, and formability by mixing a large amount of a plasticizer. However, the plasticizer causes a problem of generating a gas (also referred to as "discharge" between the plastic film and the adhesive layer when the touch screen is used in a high temperature environment.

In order to improve the foaming resistance and the peeling resistance, a method of copolymerizing a monomer having a functional group such as a carboxyl group or a mixed homopolymer is known. A method of a monomer having a high glass transition temperature (Tg) (high Tg monomer) and/or a high Tg oligomer (low molecular weight polymer). Further, in order to improve non-whitening properties and non-corrosive properties, a method of copolymerizing a crosslinkable functional acrylate other than a carboxyl group and an alkoxyalkyl acrylate is known. Further, in order to prevent outgassing, a method of adding a tackifier or a method of mixing a metal clamp is known.

Specifically, there is known an adhesive comprising 100 g of an adhesive polymer obtained by copolymerizing a carboxyl group-containing monomer with an alkoxyalkyl (meth)acrylate as a main component and copolymerizing a carboxyl group-containing monomer therein. a monomer or two or more monomers selected from the group consisting of alkyl methacrylate, cycloalkyl methacrylate, benzyl methacrylate or styrene as a main component, and copolymerized with an amine group or The low molecular weight polymer obtained by the amide group monomer is 5 to 40 parts by weight, and the crosslinking agent is 0.001 to 2.0 parts by weight (see Patent Document 1).

Further, an adhesive sheet for metal pasting is known, and an acrylic copolymer and a benzene which contain a carboxyl group-containing monomer as an essential component and which do not substantially contain a hydroxyl group-containing monomer are used in the adhesive sheet for metal adhesion. An adhesive in which a triazole or a derivative thereof is mixed in a specific weight ratio, and an epoxy crosslinking agent having a functional group capable of reacting with a carboxyl group in the acrylic copolymer is mixed and blended in a specific weight ratio The adhesive obtained in combination (refer to Patent Document 2).

Further, an adhesive having a weight average molecular weight obtained by mixing an alkoxyalkyl acrylate as a main component and copolymerizing 0.1 to 10% by weight of a carboxyl group-containing monomer therein is known. More than 10,000 100 parts by weight of the adhesive polymer, a monomer selected from alkyl methacrylate, cycloalkyl methacrylate, benzyl methacrylate or styrene as a main component, and copolymerized therein 0.5 to 10 5% by weight of a low molecular weight polymer having a glass transition temperature of 60 ° C or more and a weight average molecular weight of 50,000 or less, and crosslinking by a weight % of an amine group-containing monomer or a guanamine group-containing monomer The dose is 0.001 to 2.0 parts by weight (see Patent Document 3).

Further, a transparent double-sided adhesive tape formed of an adhesive mixed with an acrylic polymer and an oligomer containing 50% by weight or more of an alkyl group based on all the monomer components is known. An acrylate monomer having 4 to 12 carbon atoms and containing 3 to 10 parts by weight of a carboxyl group-containing monomer as a monomer component with respect to 100 parts by weight of all the monomer components, and having a weight average molecular weight of 500,000~ 90,000, the oligomer is an ethylenically unsaturated monomer having a cyclic structure and having a glass transition temperature of 60 to 190 ° C when the homopolymer is formed in an amount of 50% by weight or more based on the total of the monomer components, and is relatively The carboxyl group-containing monomer as a monomer component is contained in an amount of from 3 to 10 parts by weight based on 100 parts by weight of all the monomer components, and the weight average molecular weight is from 3,000 to 6,000 (see Patent Document 4).

Further, there is known an adhesive which is polymerized by containing an alkoxyalkyl acrylate (ingredient A) and an acrylic monomer (component B) having a crosslinkable functional group as an essential component. An acrylic polymer having a weight average molecular weight of 400,000 to 1.6 million, and an adhesive for a crosslinking agent, wherein the content of the component A is 45 to 99.5 with respect to 100 parts by weight of all the monomer components constituting the acrylic polymer. The content of the component B is 0.5 to 4.5 parts by weight, and the monomer constituting the acrylic polymer is formed by weight. The monomer does not substantially contain a carboxyl group-containing monomer (see Patent Document 5).

Further, there is known a transparent adhesive sheet which comprises an acrylate monomer (component A) having an alkyl group having 4 to 18 carbon atoms, an acrylate group-containing acrylate monomer (ingredient B), and The alkoxyalkyl acrylate is obtained by copolymerization, and has an acid value of 5 mg KOH/g or less (refer to Patent Document 6).

Further, an adhesive is known which is obtained by copolymerizing 45 to 99.5 parts by weight of an alkoxyalkyl acrylate monomer (component A) and 0.5 to 4.5 parts by weight of an acrylate monomer having a hydroxyl group. The acrylic polymer has a gel fraction of 40 to 80% after forming a crosslinked structure, and does not substantially contain a carboxyl group-containing monomer (see Patent Document 7).

Further, there is known an adhesive which is prepared by mixing styrene or α-methylstyrene in an acrylic polymer with respect to 100 parts by weight of the acrylic polymer for the purpose of suppressing outgas of the adherend. The tackifier is formed in an amount of 0.5 to 15 parts by weight and crosslinked by an isocyanate crosslinking agent (see Patent Document 8).

Further, there is known an adhesive which is formed by mixing an acrylic copolymer and a metal nip for the purpose of suppressing outgassing of an adherend, the acrylic copolymer being contained with respect to all monomers 40 to 99 parts by weight of butyl acrylate or ethyl acrylate or a mixture thereof (ingredient A), 1 to 15 parts by weight of α,β-ethylenically unsaturated carboxylic acid (ingredient B), and 0 to 55% by weight Methyl acrylate, methyl methacrylate, acrylonitrile or styrene or a mixture thereof (ingredient C), and weight average molecules The acrylic copolymer having an amount of 400,000 or more is 0.5 to 2.0 parts by weight based on 100 parts by weight of the acrylic copolymer (see Patent Document 9).

Prior technical literature

Patent literature

Patent Document 1: Japanese Laid-Open Patent Publication No. 2002-327160

Patent Document 2: Japanese Laid-Open Patent Publication No. 2006-45315

Patent Document 3: Japanese Patent No. 4788937

Patent Document 4: Japanese Patent No. 4515118

Patent Document 5: Japanese Laid-Open Patent Publication No. 2009-79203

Patent Document 6: Japanese Laid-Open Patent Publication No. 2011-74308

Patent Document 7: Japanese Laid-Open Patent Publication No. 2010-215923

Patent Document 8: Japanese Patent No. 4437631

Patent Document 9: Japanese Patent Laid-Open No. Hei 6-49425

However, the adhesives of Patent Documents 1 and 2 have a problem of corroding metals due to the presence of a carboxyl group.

Further, since the adhesion to the base film is low, the adhesives of Patent Documents 3 and 4 have poor performance in terms of foam resistance and peeling resistance. Further, since the adhesion to the transparent electrode is low, the adhesive has a problem that the step difference followability is poor.

Further, in the adhesives of Patent Documents 5, 6 and 7, although alkoxyalkyl acrylate is used to improve non-whitening property, there is an improvement in non-whitening property. The problem of low standards. Further, since the polymerization initiator is easily left in the adhesive, the alkoxyalkyl group in the polymer is easily decomposed, and there is a problem that the foaming resistance and the peeling resistance are inferior. Further, since the alkoxyalkyl acrylate to be used has a low Tg (generally at -45 ° C or lower), there is a problem that the cohesive force of the adhesive is low and the adhesive strength is insufficient.

Further, when the adhesive of Patent Document 8 is in an environment of high temperature and high humidity, since the tackifier mixed in the adhesive bleeds out, performance in terms of foam resistance and peeling resistance cannot be ensured. Furthermore, there is a problem of contamination due to the oozing. Further, the adhesive of Patent Document 9 has a problem that the metal is corroded due to the presence of the metal nip.

In view of the above problems, an object of the present invention is to provide an adhesive, an adhesive sheet, and a display which are excellent in adhesion, transparency, non-whitening property, foaming resistance, and peeling resistance, and have step-span followability.

The adhesive of the present invention contains an acrylic copolymer (A), a polyisocyanate curing agent (B), and a decane coupling agent (C), and the acrylic copolymer (A) has a SP value of 8 or more by radical polymerization. 20 to 80% by weight of the ethylenically unsaturated monomer (A1) having an alkyl group and 20 to 80% by weight of the polar group-containing ethylenically unsaturated monomer (A2) having an SP value of 9.00 or more and 15 or less. form. Further, the polar group-containing ethylenically unsaturated monomer (A2) has a group selected from the group consisting of a hydroxyl group (a1), an amidino group (a2), an amine group (a3), and a nitrile group (a4). One or more polar groups, and the glass transition temperature (Tg) of the homopolymer is set to -40 ° C or more and 120 ° C or less. Here, the SP value refers to a solubility parameter. and, The acrylic copolymer (A) is a polymer having a weight average molecular weight of 200,000 or more and 1,000,000.

According to the invention having the above configuration, the SP value of the polar group-containing ethylenically unsaturated monomer (A2) used for the synthesis of the acrylic copolymer (A) is in a high range of 9.00 or more and 15 or less. Further, the acrylic copolymer (A) using the monomer (A2) has high affinity for water. After the adhesive is processed into an adhesive tape, for example, after being adhered to a glass plate of a liquid crystal element and placed in a high-temperature and high-humidity environment, water is immersed in the adhesive layer. However, since the adhesive layer contains a copolymer (A) using a large amount of the monomer (A2) having a high SP value, it has high affinity with water. Therefore, the transparent adhesive layer is not easily whitened, and therefore is excellent in non-whitening property. That is, in the present invention, water is appropriately immersed in the adhesive layer. Further, since the pressure-sensitive adhesive layer contains a polar group, the adhesion is not easily lowered even when placed in a high-temperature and high-humidity environment, so that the peeling resistance is excellent, and since the adhesive layer is less likely to generate bubbles, the foaming resistance is obtained. Excellent. Furthermore, the step difference followability is also excellent. In addition, an environment with high temperature and high humidity refers to an environment with high temperature and high humidity.

According to the present invention, it is possible to provide an adhesive, an adhesive sheet, and a display which are excellent in adhesion, transparency, non-whitening property, foaming resistance, and peeling resistance, and have step-span followability.

As the adhesive of the present invention, at least an acrylic copolymer is mixed (A), a polyisocyanate hardener (B) and a decane coupling agent (C).

The acrylic copolymer (A) has a polarity of 20 to 90% by weight of an alkyl group-containing ethylenically unsaturated monomer (A1) having a SP value of 8 or more and less than 9.00, and an SP value of 9.00 or more and 15 or less. The ethylenically unsaturated monomer (A2) is obtained in an amount of 10 to 80% by weight.

The adhesive of the present invention is used in the synthesis of the acrylic copolymer (A) by using an epoxy group-containing ethylenically unsaturated monomer (A2) having an SP value of 9.00 or more and 15 or less in an amount of 10 to 80% by weight, adhesion and resistance. The peelability is improved, especially the non-whitening property is improved. For this reason, the acrylic copolymer (A) using the monomer has high affinity for water. Further, when the adhesive of the present invention is processed into an adhesive tape, for example, adhered to a glass plate of a liquid crystal element and placed in a high-temperature and high-humidity environment, although water is immersed in the adhesive layer, it is used because it contains The amount of the copolymer (A) of the monomer (A2) having a high SP value is high, and thus the affinity with water is high. Therefore, the transparent adhesive layer is not easily whitened, and therefore is excellent in non-whitening property. That is, in the present invention, water is appropriately immersed in the adhesive layer. Further, since the pressure-sensitive adhesive layer contains a polar group, the adhesion is not easily lowered even when placed in an environment of high temperature and high humidity, and therefore the peeling resistance is excellent. Further, since the adhesive layer is less likely to generate bubbles, the foaming resistance is excellent. Furthermore, the step difference followability is also excellent. The polar group is preferably a hydroxyl group (a1), a guanamine group (a2), an amine group (a3), a nitrile group (a4), and a carboxyl group (a5).

In the present invention, the SP value is a solubility parameter. The SP value can refer to the algorithm of Fedors ["Polymer Engineering and Science", 14th, 2nd (1974), pp. 148-154], according to the following mathematical formula 1 Calculate by calculation.

Where δ is the solubility parameter (SP value), Δei is the evaporation heat of the mole, Δvi is the molar volume, and the solubility parameter unit here is (cal/cm ³ ) ^0.5 .

For the above formula 1, the eigenvalues of Δei and Δvi given to the main atom or atomic group are listed in Table 1.

In Table 1, Δei is the molar evaporation heat (cal/mol), and Δvi is the molar volume (cm ³ /mol).

Further, the solubility parameter (SP value) of the main monomer calculated according to the above formula and the glass transition temperature of the homopolymer are listed in Table 2.

The ethylenically unsaturated monomer (A2) having a polar group having an SP value of 9.00 or more and 15 or less (hereinafter referred to as a monomer (A2)) may, for example, be 2-hydroxyethyl (meth)acrylate. 2-hydroxypropyl (meth)acrylate, 3-hydroxypropyl (meth)acrylate, 2-hydroxybutyl (meth)acrylate, 3-hydroxybutyl (meth)acrylate, (A) A hydroxyl group-containing ethylenically unsaturated monomer (a1), (meth) acrylamide, or N-methylol propylene oxime such as a hydroxyalkyl (meth) acrylate such as 4-hydroxybutyl acrylate. Amine, N,N-dimethyl(meth)acrylamide, diacetone (meth)acrylamide, N-vinylacetamide, N-vinylpyrrolidone, etc. Base ethylenically unsaturated monomer (a2), aminomethyl (meth) acrylate, dimethylaminomethyl (meth) acrylate, dimethylaminoethyl (meth) acrylate An amine group-containing ethylenically unsaturated monomer (a3) such as dimethylaminopropyl (meth) acrylate or a nitrile group-containing ethylenically unsaturated monomer such as acrylonitrile or methacrylonitrile ( A4), (meth)acrylic acid, phthalic acid monohydroxyethyl acrylate, p-carboxybenzyl acrylate, ethylene oxide addition molar number of 2 to 18 phthalic acid acrylate, adjacent Monohydroxypropyl phthalate, monohydroxyethyl succinate, 2-carboxyethyl acrylate, 2-(4-benzylidene-3-hydroxyphenoxy)ethyl acrylate, horse A carboxyl group-containing ethylenically unsaturated monomer (a5) such as acid, monoethyl maleate, methylene succinic acid, methyl maleic acid or fumaric acid. These monomers may be used singly or in combination of two or more. Among these monomers, a hydroxyl group-containing ethylenically unsaturated monomer (a1) and a decylamino group-containing ethylenically unsaturated monomer (a2) are preferred from the viewpoints of non-whitening property, foaming resistance, and peeling resistance. And an amino group-containing ethylenically unsaturated monomer (a3), in particular, a hydroxyl group-containing ethylenically unsaturated monomer (a1) is further preferable. Further, although it does not exist in the above enumeration, a monomer having an SP value in the range of 9.00 or more and 15 or less when calculated according to the calculation formula of Mathematical Formula 1 can be used.

Further, as the monomer (A2), the glass transition temperature (Tg) of the homopolymer is preferably -40 ° C or more and 120 ° C or less. When the glass transition temperature (Tg) of the homopolymer is within the above range, the adhesion and the peeling resistance can be further improved. The glass transition temperature (Tg) of the homopolymer is more preferably from -30 ° C to 100 ° C.

In the present invention, the glass transition temperature (Tg) of the homopolymer of the monomer (A2) is referred to the "Handbook of Polymers" 4th edition by J. Brandrup, EHImmergut and EAGrulke (Polymer Handbook, Fourth Edition, 1999). ).

The monomer (A2) is preferably used in an amount of 10 to 80% by weight based on 100% by weight of all the monomers. By using the monomer (A2) in an amount of 10 to 80% by weight, non-whitening property is improved, and adhesion and peeling resistance are also improved. Further, it is more preferred to use the monomer (A2) in an amount of 20 to 60% by weight.

In the synthesis of the acrylic copolymer (A), it is preferred to use an ethylenically unsaturated monomer (A1) having an alkyl group having an SP value of 8 or more and less than 9.00 in addition to the monomer (A2) at 20 to 90% by weight. . When the SP value is in the range of 8 or more and less than 9.00, since the polarity of the acrylic copolymer (A) is suitable, the adhesion to the adherend having high polarity such as metal, glass, or plastic can be improved, and the peeling resistance can be improved. And non-whitening is also improved.

In the present invention, as the monomer (A1), for example, an alkyl (meth)acrylate monomer having an alkyl group having 1 to 20 carbon atoms is preferable. Specifically, for example, methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, butyl (meth)acrylate, amyl (meth)acrylate, (methyl) ) hexyl acrylate, cyclohexyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, isooctyl (meth) acrylate, decyl (meth) acrylate, (meth) acrylate Dialkyl ester, tetradecyl (meth) acrylate, cetyl (meth) acrylate, octadecyl (meth) acrylate, and cyclohexyl (meth) acrylate, (A) base) A cycloalkyl (meth)acrylate such as isodecyl acrylate. These monomers may be used singly or in combination of two or more. Among these monomers, in particular, butyl (meth)acrylate and 2-ethylhexyl (meth)acrylate are more preferable because they can obtain moderate adhesion and are easy to adjust the weight average molecular weight.

The monomer (A1) is preferably used in an amount of 20 to 90% by weight based on 100% by weight of all the monomers. By using the monomer (A1) at 20 to 90% by weight, the acrylic copolymer (A) in a suitable weight average molecular weight range can be synthesized, and the peeling resistance and the non-whitening property can be further improved. The amount of use of the monomer (A1) is more preferably 40 to 80% by weight.

In the present invention, other ethylenically unsaturated monomers can be used within a range not impairing the effects of the invention. Specific examples thereof include methoxyethyl (meth)acrylate, phenoxyethyl (meth)acrylate, methoxypolyethylene glycol (meth)acrylate, and ethoxypolyethylene glycol ( An alkylene oxide-containing ethylenically unsaturated monomer such as methyl acrylate, phenoxy polyethylene glycol (meth) acrylate or methoxy polypropylene glycol (meth) acrylate, and vinyl acetate A vinyl monomer such as vinyl butenoate or styrene. These monomers may be used singly or in combination of two or more.

Further, the acrylic polymer in the present invention means a polymer of an ethylenically unsaturated monomer containing a (meth) acrylate monomer. Further, in the present invention, the (meth) acrylate monomer means both an acrylate monomer and a methacrylate monomer. Other similar terms are the same. Further, the polymer means both "homopolymer" and "copolymer".

In the present invention, it can be through solution polymerization, emulsion polymerization, suspension polymerization Synthetic synthetic acrylic copolymer (A). Among these polymerization methods, solution polymerization is preferred from the viewpoint of transparency and adhesion. Further, the weight average molecular weight of the acrylic copolymer (A) is preferably from 200,000 to 1,000,000. By controlling the weight average molecular weight within the above range, the adhesion and the peeling resistance can be further improved. Further, it is further preferred that the weight average molecular weight is from 400,000 to 800,000. As the acrylic copolymer (A), two or more copolymers having different weight average molecular weights may be used.

Further, the molecular weight distribution (Mw/Mn) indicating the weight average molecular weight (Mw) and the number average molecular weight (Mn) ratio of the acrylic copolymer (A) is preferably 20 or less. By controlling the molecular weight distribution to 20 or less, the adhesion and the peeling resistance can be further improved. Further, the weight average molecular weight and the number average molecular weight are values in terms of polystyrene measured by gel permeation chromatography (GPC).

The acrylic copolymer (A) is obtained by radically polymerizing an ethylenically unsaturated monomer using a radical polymerization initiator. When the radical polymerization is carried out by solution polymerization, for example, polymerization is preferably carried out in the presence of a solvent such as ethyl acetate, toluene, xylene, anisole, methyl ethyl ketone or cyclohexanone. The radical polymerization temperature is preferably in the range of 60 to 120 ° C, and preferably the polymerization time is 5 to 12 hours.

A known initiator can be used as the radical polymerization initiator, but it is not particularly limited as long as it is a compound capable of generating a radical at a polymerization temperature. For example, di-terternary butyl peroxide, dicumyl peroxide, tri-butyl cumyl peroxide, α,α'-bis(tri-butylperoxy-inter) Isopropyl)benzene, 2,5-di(tri-butylperoxy) Dialkyl peroxides such as hexyne-3, tertiary butyl peroxybenzoate, tertiary butyl peroxyacetate, 2,5-dimethyl-2,5-di Peroxyesters such as (benzimidylperoxy)hexane, cyclohexanone peroxide, 3,3,5-trimethylcyclohexanone peroxide, methylcyclohexanone peroxide Ketone peroxides, 2,2-bis(4,4-ditributylbutoxycyclohexyl)propane, 1,1-bis(tri-butylperoxy)3,3,5 -trimethylcyclohexane, 1,1-bis(tertiarybutylperoxy)cyclohexane, n-butyl-4,4-bis(tertiarybutylperoxy)trimethylacetate Hydroperoxides such as peroxy ketals, cumene hydroperoxide, diisopropylbenzene hydroperoxide, 2,5-dimethylcyclohexane-2,5-dihydroperoxide , bismuthinoyl peroxide, sulfhydryl peroxide, lauryl peroxide, 2,4-dichlorobenzhydryl peroxide, etc. An organic peroxide such as a peroxydicarboxylate such as a butylcyclohexyl)peroxydicarboxylate or a mixture thereof.

Further, an azo compound can also be used as the radical polymerization initiator. As an example, 2,2'-azobispyrene such as 2,2'-azobisisobutyronitrile (abbreviated as AIBN) or 2,2'-azobis(2-methylbutyronitrile) can be used. Nitriles, 2,2'-azobis(4-methoxy-2,4-dimethylvaleronitrile), 2,2'-azobis(2,4-dimethylvaleronitrile), etc. 2,2'-azobisvaleronitrile, 2,2'-azobispropionitrile such as 2,2'-azobis(2-hydroxymethylpropionitrile), 1,1'-azo 1,1'-azobis-1-alkanonitrile such as bis(cyclohexane-1-carbonitrile).

The radical polymerization initiator is preferably used in an amount of 0.01 to 10 parts by weight, more preferably 0.1 to 2 parts by weight, based on 100 parts by weight of the ethylenically unsaturated monomer.

In the present invention, the polyisocyanate hardener (B) preferably has two The above isocyanato aromatic polyisocyanate, aliphatic polyisocyanate, aromatic aliphatic polyisocyanate, and alicyclic polyisocyanate.

Examples of the aromatic polyisocyanate include 1,3-phenylene diisocyanate, 4,4'-diphenyl diisocyanate, 1,4-phenylene diisocyanate, and 4,4'-diphenylmethane. Diisocyanate, 2,4-methylphenylene diisocyanate, 2,6-methylphenylene diisocyanate, 4,4'-tolidine diisocyanate, 2,4,6-triisocyanate 1,3,5-triisocyanatophenyl ester, dimethoxyaniline diisocyanate, 4,4'-diphenyl ether diisocyanate, 4,4',4"-triphenylmethane triisocyanate, and the like.

Examples of the aliphatic polyisocyanate include trimethylene diisocyanate, tetramethylene diisocyanate, hexamethylene diisocyanate (also referred to as HMDI), pentamethylene diisocyanate, and 1,2-propylene group II. Isocyanate, 2,3-butylene diisocyanate, 1,3-butylene diisocyanate, dodecamethylene diisocyanate, 2,4,4-trimethylhexamethylene diisocyanate, and the like.

As the aromatic aliphatic polyisocyanate, for example, ω,ω'-diisocyanate-1,3-dimethylbenzene, ω,ω'-diisocyanate-1,4-dimethylbenzene, ω,ω'- can be cited. Diisocyanate-1,4-diethylbenzene, 1,4-tetramethylbenzenedimethylene diisocyanate, 1,3-tetramethylbenzenedimethylene diisocyanate, and the like.

As the alicyclic polyisocyanate, for example, 3-isocyanate-methylene-3,5,5-trimethylcyclohexyl isocyanate (abbreviated as IPDI, isophorone diisocyanate), 1,3-cyclopentane can be cited. Alkyl diisocyanate, 1,3-cyclohexane diisocyanate, 1,4-cyclohexane diisocyanate, methyl-2,4-cyclohexane diisocyanate, methyl-2,6-cyclohexane diisocyanate, 4,4'-methylenebis(cyclohexyl isocyanate), 1,4-bis(isocyanatemethylene)cyclohexane or the like.

Further, examples thereof include a biuret compound, a trimer, an adduct, and the like of the above polyisocyanate.

The biuretide refers to a self-condensation product having a biuret bond formed by condensation of the above isocyanate monomer itself, and for example, a biuret compound of hexamethylene diisocyanate (Sumidur N-75, Suvarh Bayer) Polyurethane company, Duranate 24A-90CX, manufactured by Asahi Kasei Co., Ltd.).

The trimer refers to a trimer of the above isocyanate monomer, and examples thereof include a trimer of hexamethylene diisocyanate (Sumidur N-3300, manufactured by Sumiy Bayer Polyurethane Co., Ltd., Coronate HX, Made by Japan Polyurethane Industry Co., Ltd., Aquanate 100, manufactured by Japan Polyurethane Industry Co., Ltd., Aquanate 110, manufactured by Japan Polyurethane Industry Co., Ltd., Duranate TPA100, manufactured by Asahi Kasei Co., Ltd.), a trimer of isophorone diisocyanate (VESTANAT T-1890, Evonik Degussa) Japanese company, Desmodur Z-4370, manufactured by Bayer Polyurethane Co., Ltd.), trimer of phenylene diisocyanate (Coronate 2030, manufactured by Japan Polyurethane Industry Co., Ltd.), and the like.

The adduct is a difunctional or higher isocyanate compound formed by reacting the above isocyanate monomer and a low molecular weight active hydrogen-containing compound, and examples of the trifunctional isocyanate compound include trimethylolpropane and hexamethylene. A compound formed by the reaction of diisocyanate (Coronate HL, manufactured by Japan Polyurethane Industry Co., Ltd., Sumidur HT, manufactured by Surin Bayer Polyurethane Co., Ltd., Takenate D-160N, manufactured by Mitsui Chemical Polyurethane Co., Ltd.), and trimethylol a compound formed by reacting propane with phenylene diisocyanate (Coronate L, Japan Polyurethane Industry Corporation System, Sumidur L-75, made by Bayer Polyurethane Co., Ltd., Takenate D-102, manufactured by Mitsui Chemicals Polyurethane Co., Ltd.), reacting trimethylolpropane and phenylenediethylene diisocyanate to form Compound (Takenate D-110N, manufactured by Mitsui Chemicals Polyurethane Co., Ltd.), a compound formed by reacting trimethylolpropane and isophorone diisocyanate (Takenate D-140N, Mitsui Chemical Polyurethane Co., Mitec NY215A, Mitsubishi Chemical Corporation) The bifunctional isocyanate compound is an allophanate compound obtained from 1,6-hexamethylene diisocyanate and a monohydric alcohol (Duranate D-201, manufactured by Asahi Kasei Co., Ltd., Coronate 2770, Japan) Polyurethane Industry Co., Ltd.).

Further, examples of the low molecular weight active hydrogen-containing compound include ethylene glycol, propylene glycol, diethylene glycol, butylene glycol, 1,6-hexanediol, 3-methyl-1,5-pentanediol, and 3 , 3'-dimethylol heptane, 2-methyl-1,8-octanediol, 3,3'-dimethylol heptane, 2-butyl-2-ethyl-1,3- Propylene glycol, polyethylene glycol (additional molar number below 10), polypropylene glycol (additional molar number below 10), 1,4-butanediol, 1,5-pentanediol, 1,6- Hexanediol, 1,8-octanediol, 1,9-nonanediol, neopentyl glycol, butyl ethyl pentanediol, 2-ethyl-1,3-hexanediol, cyclohexanediol An aliphatic or alicyclic diol such as cyclohexanedimethanol, tricyclodecane dimethanol, cyclopentadiene dimethanol or dimer alcohol, 1,3-bis(2-hydroxyethoxy) Benzene, 1,2-bis(2-hydroxyethoxy)benzene, 1,4-bis(2-hydroxyethoxy)benzene, 4,4'-methylenebiphenol, 4,4'-(2 - sub-norbornene) biphenol, 4,4'-dihydroxybiphenol, o-, m- and p-dihydroxybenzene, 4,4'-isopropylidene propyl phenol, or in bisphenol A or bisphenol Bisphenol formed by adding an alkylene oxide such as ethylene oxide or propylene oxide to a bisphenol such as F Wait Aromatic diols, 1,1,1-trimethylolpropane, 1,1,1-trimethylolbutane, 1,1,1-trimethylolpentane, 1,1,1 - Trimethylol hexane, 1,1,1-trishydroxymethylheptane, 1,1,1-trimethylol octane, 1,1,1-trishydroxymethyl decane, 1,1 , 1-trimethylol decane, 1,1,1-trimethylolundecane, 1,1,1-trimethyloldodecane, 1,1,1-trimethyloltride Alkane, 1,1,1-trimethyloltetradecane, 1,1,1-trimethylolpentadecane, 1,1,1-trimethylolhexadecane, 1,1,1- Trimethylolhexadecane, 1,1,1-trishydroxymethyloctadecane, 1,1,1-trimethylolpentadecane, 1,1,1-trishydroxyhydroxybutane, 1,1,1-trimethylol tertiary pentane, 1,1,1-trishydroxymethyltridecane, 1,1,1-trishydroxymethyltritridecane, 1,1, 1-trimethylol tertiary heptadecane, 1,1,1-trishydroxymethyl-2-methyl-hexane, 1,1,1-trishydroxymethyl-3-methyl-hexane, 1,1,1-trishydroxymethyl-2-ethyl-hexane, 1,1,1-trishydroxymethyl-3-ethyl-hexane, 1,1,1-trimethylol Trimethylol branched alkanes such as heptane, trimethylolbutene, trimethylol heptene, trimethylolpentene, trimethylolhexene, trimethylol heptene, three Methylol octene, trishydroxymethyl nonene, trimethyloldodecene, trimethyloltridecene, trimethylolpentadecene, trimethylolhexadecene, trimethylol10 Trifunctional polyols such as hepene, trimethylol octadecene, 1,2,6-butane triol, 1,2,4-butane triol, glycerin, etc., pentaerythritol, dipentaerythritol, sorbitol, A tetrafunctional or higher polyhydric alcohol such as xylitol, ethylenediamine, propylenediamine, butanediamine, pentanediamine, hexamethylenediamine, heptanediamine, octanediamine, decanediamine, diaminobicyclic Hexylmethane, 3-aminomethyl-3,5,5-trimethylcyclohexylamine, 1,3-bis(aminomethyl)cyclohexane, triethylenetetramine, diethylenetriamine An aliphatic polyamine such as triaminopropane, an aromatic polyamine such as phenylene diamine, phenylenediamine, diaminodiphenylmethane or diaminodiphenyl ether. B Dithiol, propylene dithiol, butyl dithiol, pentanethiol, hexanedithiol, heptanedithiol, octanedithiol, decanedithiol, dimercaptodicyclohexylmethane, 3-mercapto -3,5,5-trimethylcyclohexyl mercaptan, 1,3-bis(decylmethyl)cyclohexane, 1,4-bis(3-mercaptobutyloxy)butane, pentaerythritol tetra ( A polythiol such as 3-mercaptobutyrate).

The polyisocyanate-based curing agent (B) of the present invention can be obtained by reacting the above-mentioned isocyanate monomer and a low molecular weight active hydrogen-containing compound. In this case, the isocyanate monomer and the low molecular weight active hydrogen-containing compound may be used alone or in combination of two or more.

A polyfunctional isocyanate compound is also preferable in the polyisocyanate-based curing agent (B) for the reason that a sufficient crosslinked structure is formed. Further, in view of adhesion, adhesion durability, and the like, an adduct is preferable, and a trimethylolpropane adduct of hexamethylene diisocyanate or a trimethylolpropane of phenylene diisocyanate is preferable. a trifunctional isocyanate compound such as an adduct, a trimethylolpropane adduct of isophorone diisocyanate, a trimethylolpropane adduct of phenyldimethylene diisocyanate, and 1,6-hexa An allophanate compound prepared from methylene diisocyanate and a monohydric alcohol. In particular, a bifunctional isocyanate compound is more preferable from the viewpoint of adhesion and moist heat resistance. These polyisocyanate hardeners (B) may be used alone or in combination of two or more.

In the present invention, the polyisocyanate curing agent (B) is preferably used in an amount of 0.01 to 10 parts by weight, more preferably 0.05 to 8 parts by weight, still more preferably 0.1 to 5 parts by weight, per 100 parts by weight of the acrylic copolymer (A). .

In the present invention, as a range which does not impair the effects of the present invention, it is hardened. A polyfunctional epoxy compound may also be used in combination. By using a polyfunctional epoxy compound in combination, the heat resistance of the adhesive layer can be further improved. Examples of the polyfunctional epoxy compound include ethylene glycol diglycidyl ether, polyethylene glycol diglycidyl ether, 1,6-hexanediol diglycidyl ether, and bisphenol A/epichlorohydrin type epoxy. Resin, N, N, N'N'-tetraglycidyl-m-xylylenediamine, 1,3-bis(N,N-diglycidylaminomethyl)cyclohexane, N,N-di Glycidylaniline, N,N-diglycidyltoluidine, and the like.

In the present invention, the polyfunctional epoxy compound is preferably used in an amount of 0.1 to 5 parts by weight based on 100 parts by weight of the copolymer (A).

In a display such as a touch panel, a conductive line having a step of about 10 to 30 μm formed of a silver paste or the like is often provided at the edge portion of the transparent conductive film. Therefore, when the adhesive tape using the adhesive of the present invention is adhered to the conductive line, the combination effect of the acrylic copolymer (A) and the polyisocyanate hardener (B) can be achieved at the corner of the step or the like. Excellent step followability of residual bubbles. Here, examples of the transparent conductive film include a metal thin film such as an ITO (indium/tin) film, a conductive polymer film such as polythiophene or polyaniline, and the like. Further, in the present invention, the step-embedded embedding property means a step-difference embedding property at a low-temperature heat lamination of about 40 ° C to 50 ° C, and should be carried out in a dry film state in the field of printed wiring board technology. The adhesive sheet is laminated on the wiring circuit at a temperature of about 80 ° C to 200 ° C to distinguish the high-temperature heat lamination with a step difference.

In the present invention, by using the decane coupling agent (C), the adhesion of the adhesive layer and the adherend can be improved, and the foaming resistance and the peeling resistance can be improved.

Specific examples of the decane coupling agent (C) include γ-(meth)acryloxymethyltrimethoxydecane, γ-(meth)acryloxypropyltrimethoxydecane, and γ. -(Methyl)acryloxypropyltriethoxydecane, γ-(meth)acryloxypropyltributoxydecane, γ-(meth)acryloxypropylmethyldi Alkoxydecane compound having a (meth)acryloxy group, such as methoxy decane or γ-(meth) propylene methoxy propyl methyl diethoxy decane, vinyl trimethoxy decane, ethylene Alkoxy decane compound having a vinyl group such as triethoxy decane, vinyl tributoxy decane or vinyl methyl dimethoxy decane, γ-aminopropyltrimethoxy decane, γ-amine An alkoxydecane compound having an aminoalkyl group such as propyl triethoxy decane, γ-aminopropyl methyl dimethoxy decane or γ-aminopropyl methyl diethoxy decane, Γ-mercaptopropyltrimethoxydecane, γ-mercaptopropyltriethoxydecane, γ-mercaptopropylmethyldimethoxydecane, γ-mercaptopropylmethyldiethoxydecane, β-mercapto Alkoxydecane compound having a mercapto group, such as phenylethyltrimethoxydecane, mercaptomethyltrimethoxydecane, 6-decylhexyltrimethoxydecane, 10-mercaptodecyltrimethoxydecane, methyltrimethyl Oxy decane, methyl triethoxy decane, dimethyl dimethoxy decane, dimethyl diethoxy decane, ethyl trimethoxy decane, ethyl triethoxy decane, diethyl dimethyl An alkoxydecane compound having an alkyl group such as oxydecane, diethyldiethoxydecane, hexyltrimethoxydecane or decyltrimethoxydecane, phenyltrimethoxydecane, phenyltriethoxy Alkoxydecane compound having a phenyl group such as decane, phenyltripropoxydecane or phenyltributyloxane, tetramethoxynonane, tetraethoxydecane, tetrabutoxydecane, tetrapropoxy No substitution of decane, etc. Alkoxydecane compound, 3-glycidoxypropyltrimethoxydecane, 3-glycidoxypropyltriethoxydecane, 3-glycidoxypropylmethyldimethoxydecane The alkoxydecane compound having a glycidyl group, and the alkoxydecane compound, 2-(3,4-epoxycyclohexyl)ethyltrimethoxydecane, 2-(3,4) -Epoxycyclohexyl)ethyltriethoxydecane, 3-chloropropylmethyldimethoxydecane, 3-chloropropyltrimethoxydecane, hexamethylguanidine, diphenyldimethyl Oxydecane, 1,3,5-tris(3-trimethoxycarbamidopropyl)isocyanurate, vinyltris(2-methoxyethoxy)decane, N-(2-amine Benzyl)-3-aminopropylmethyldimethoxydecane, N-(2-aminoethyl)-3-aminopropyltrimethoxydecane, 3-isocyanatepropyltriethoxy Base decane and the like.

The decane coupling agent (C) is preferably present in the adhesive layer in the form of a ruthenium coupling of a decane coupling agent in which an alkoxy group is hydrolyzed. By adopting such a form, it is easy to affinity with water intruding into the adhesive layer, so that non-whitening property can be further improved. Further, it is further preferred that the decane coupling agent (C) relatively freely moves in the adhesive layer and is in contact with water. Therefore, in order to further improve the non-whitening property, it is more preferable that the decane coupling agent (C) has no reactive functional group other than the alkoxy group or a functional group which does not easily react with the functional group of the acrylic copolymer (A). For example, it is further preferred to have an alicyclic epoxy group other than the alkoxy group. Further, it should be noted that the description is not intended to prevent the decane coupling agent (C) from having a reactive functional group other than an alicyclic epoxy group.

Examples of the decane coupling agent having an alicyclic epoxy group include 2-(3,4-epoxycyclohexyl)ethyltrimethoxynonane and 2-(3,4-epoxycyclohexyl). Ethyltriethoxydecane, and the like. Further, the "decane coupling agent having no reactive group other than an alkoxy group" means the above alkoxydecane compound having an alkyl group, an alkoxydecane compound having a phenyl group, and an alkoxydecane having no substituent. Compound. Further preferred are 2-(3,4-epoxycyclohexyl)ethyltrimethoxynonane, methyltriethoxydecane, tetraethoxydecane, and phenyltriethoxydecane. Further, the decane coupling agent (C) may be used alone or in combination of two or more.

The decane coupling agent (C) is preferably used in an amount of 0.001 to 1 part by weight based on 100 parts by weight of the acrylic copolymer (A). By using the decane coupling agent (C) in the above range, the adhesion can be further improved. The decane coupling agent (C) is further preferably used in an amount of 0.005 to 0.8 parts by weight.

As the adhesive of the present invention, in addition to the acrylic copolymer (A), the polyisocyanate curing agent (B), and the decane coupling agent (C), other resins may be used in combination, for example, acrylic resin or polyester may be used in combination. Resin, amine based resin, epoxy resin, polyurethane resin. Further, depending on the application, a filler such as a coupling agent, a tackifier, talc, calcium carbonate or titanium oxide, a coloring agent, a softening agent, an ultraviolet absorber, an antioxidant, an antifoaming agent, a light stabilizer, and a weathering stabilizer may be mixed. An additive such as a hardening accelerator, a hardening retarder, or a phosphate ester.

The adhesive sheet of the present invention preferably contains at least an adhesive layer formed of the above-described adhesive composition. The adhesive sheet can be obtained by applying an adhesive on a release paper. Alternatively, the adhesive sheet can also be obtained by directly applying an adhesive to the substrate. In the case of an adhesive sheet, it is possible to form an adhesive layer by applying an adhesive on a release paper and then attaching the release paper. The adhesive sheet of the substrate is used as a cast adhesive sheet. Further, the substrate is a material that can sufficiently adhere to the adhesive layer and is not easily peeled off. On the other hand, the release paper is a material which is easily peeled off from the adhesive layer by a peeling treatment or the like. In the present invention, the adhesive tape, the adhesive sheet, and the adhesive film are synonymous.

A suitable liquid medium can be added to the viscosity of the adhesive to adjust the viscosity. Specifically, for example, a hydrocarbon solvent such as toluene, xylene, hexane or heptane, an ester solvent such as ethyl acetate or butyl acetate, a ketone solvent such as acetone or methyl ethyl ketone, or dichloromethane or chloroform may be mentioned. A halogenated hydrocarbon solvent such as diethyl ether, methoxytoluene or an ether solvent such as dioxane or another hydrocarbon solvent. Among them, water or alcohol may be used cautiously because it may cause a reaction inhibition of the acrylic copolymer (A) and the polyisocyanate hardener (B).

The coating method is not particularly limited, and examples thereof include wire bar coating, coater coating, brush coating, spray coating, roll coating, gravure roll coating, die coating, coincidence roll coating, comma coating, blade coating, and reversal. Various coating methods such as roll coating and spin coating. The drying method is not particularly limited, and examples thereof include hot air drying and a drying method using infrared rays or a reduced pressure method. As drying conditions, it is usually possible to heat with hot air or steam of about 60 to 180 °C.

In the present invention, the substrate is not particularly limited, and examples thereof include various optical films such as a plastic film, an antireflection (AR) film, a polarizing plate, and a phase difference plate. Examples of the plastic film include a polyvinyl chloride film, a polyethylene film, a polyethylene terephthalate (PET) film, a polyurethane film, a nylon film, a polyolefin film, a triacetyl cellulose film, and a ring. Olefin film and the like. For substrates The thickness is not particularly limited, but is preferably 10 to 2000 μm.

The thickness of the adhesive layer is preferably 2 to 1000 μm, and more preferably 5 to 500 μm. Further, the adhesive layer may be a single layer or a laminate of two or more layers.

The adherend (adhesive member) of the adhesive sheet of the present invention is not particularly limited, but an acrylic plate, a polycarbonate plate, a cycloolefin film, glass, or polyethylene terephthalate having a transparent conductive film is preferable. board.

The adhesive sheet of the present invention is preferably used in the bonding of optical members. When the optical member is in the form of a sheet, it is also referred to as an optical film, and specifically, a polarizing film, a retardation film, an elliptically polarizing film, an antireflection film, a brightness enhancement film, or the like can be given.

By adhering the above-mentioned optical member to the adhesive sheet of the base material, for example, a glass member for a liquid crystal element, a liquid crystal element member in which a sheet-shaped optical member/adhesive layer/glass member for a liquid crystal element is laminated in this order can be obtained. In the present invention, when the optical member is a polarizing plate, it is particularly useful, and a laminate having good peeling resistance can be obtained.

Further, since it can be used in a liquid crystal element member, the adhesive sheet of the present invention can be used in a display such as a liquid crystal panel, a plasma display panel (PDP) or the like. Further, it is further preferred to use the adhesive sheet of the present invention in the process of manufacturing these displays into a touch screen. In particular, it is preferable to directly adhere to the surface of the touch screen in which the transparent conductive film and the conductive line are formed. Even in this case, since the step difference of the step of embedding the conductive line is good, the bubble mixing inside the touch screen can be minimized. Furthermore, in the adhesive sheet of the present invention, it is difficult to be placed in a high-temperature and high-humidity environment by various compositions of the adhesive layer. In order to cause corrosion of the conductive line, and the transparency of the adhesive layer is also hard to be damaged. Further, it is preferable to use the adhesive sheet of the present invention when adhering to a plastic substrate such as an acrylic plate or a polycarbonate plate as a touch screen support. Even in this case, the outgas of the plastic substrate can be suppressed, and even if it is placed in a high-temperature or high-temperature high-humidity environment, floating or peeling does not occur, and high transparency can be maintained.

As described above, in addition to being suitable as an adhesive for optical members, the adhesive of the present invention is also very suitable as a general sticker label, paint, elastic wall material, coating waterproof material, flooring material, tackifier, Adhesives, adhesives for laminate structures, sealants, forming materials, coating agents for surface modification, adhesives (magnetic storage media, ink binders, casting binders, sintered brick binders, graft materials, microcapsules) , glass fiber sizing agent, etc., polyurethane foam (hard, semi-rigid, soft), polyurethane RIM, UV/EB hardening resin, high solid coating, thermosetting elastomer, microcellular foaming material, fiber processing agent, plasticizer, Sound absorbing material, shock absorbing material, surfactant, gel coating agent, resin for artificial marble, impact resistance imparting agent for artificial marble, resin for ink, film (lamination adhesive, protective film, etc.), laminated glass Raw materials such as resins, reactive diluents, various molding materials, elastic fibers, artificial leather, synthetic leather, or the like, or used as various resin additives and raw materials.

Example 1

Hereinafter, the present invention will be further specifically described in conjunction with the examples, but the present invention is not limited by the examples. Further, in the following examples, "parts by weight" means "parts by weight" and "%" means "% by weight".

<Synthesis Example 1>

Using a reaction apparatus having a stirrer, a reflux cooling tube, a nitrogen gas conduit, a thermometer, and a dropper, 50% by weight of the total amount of each monomer in Table 3, an appropriate amount of azobisisobutyronitrile as a starter, and a solvent Ethyl acetate was added to the reaction tank. Subsequently, all of the remaining monomers, and an appropriate amount of ethyl acetate and azobisisobutyronitrile were added and mixed, and the solution was added dropwise to the reaction tank by a dropper for about 2 hours, followed by a nitrogen atmosphere. Polymerization was carried out at about 80 ° C for 5 hours. After the reaction was completed, it was cooled and diluted with ethyl acetate to obtain a nonvolatile content of 40% and a viscosity of 3000 mPa. s copolymer solution. Here, the obtained copolymer was referred to as a copolymer (A-1).

<Synthesis Example 2 to 36>

Each of the raw materials was added in a weight ratio of Tables 3 and 4, and an acrylic copolymer was synthesized in the same manner as in Synthesis Example 1. Further, the weight average molecular weight of the obtained acrylic copolymer is shown in Tables 3 and 4.

<Measurement of Weight Average Molecular Weight (Mw)>

The GPC "LC-GPC system" manufactured by Shimadzu Corporation was used for the measurement of the weight average molecular weight. GPC is a liquid chromatograph for separating and quantifying a substance dissolved in a solvent (THF: tetrahydrofuran) according to the difference in molecular size, and is converted into polystyrene when the weight average molecular weight is determined.

Device name: Shimadzu Corporation's system, LC-GPC system "Prominence"

Pipe column: Four GMOXLs made by Tosoh Corporation and one HXL-H made by Tosoh Corporation are connected in series.

Mobile phase solvent: tetrahydrofuran

Flow rate: 1.0mL/min

Column temperature: 40 ° C

<Example 1>

With respect to 100 parts by weight of the copolymer solution obtained in Synthesis Example 1, 1.0 part of a 50% ethyl acetate solution of a dimethylene diisocyanate trimethylolpropane adduct was mixed, and as a decane coupling agent. KBE-403 (manufactured by Shin-Etsu Chemical Co., Ltd.) was 0.2 parts, thereby obtaining an adhesive.

The obtained adhesive was applied to a release paper (thickness: 38 μm) by a comma coater and dried to a thickness of 25 μm, and after drying at 100 ° C for 2 minutes, other release paper was adhered to the adhesive layer, in this state. The film was aged at room temperature for 7 days to obtain a cast adhesive sheet.

<Examples 2 to 17, 19 to 22, 24 to 34, Reference Examples 18, 23, 35, and Comparative Examples 1 to 19>

As shown in Tables 5 and 6, in addition to changing the type of copolymer and hardener, A substrate-free adhesive sheet was obtained in the same manner as in Example 1 except that the type and the amount of the decane coupling agent were used. Further, in the present specification, Examples 18, 23 and 35 are reference examples.

The adhesives and adhesive sheets obtained in Examples 1 to 17, 19 to 22, 24 to 34, Reference Examples 18, 23, and 35 and Comparative Examples 1 to 19 were evaluated as basic physical properties by the following methods. Coating properties, adhesion, foaming resistance, peeling resistance, and transparency. Further, evaluations of heat resistance, moist heat resistance, removability, non-corrosiveness, wet heat whitening resistance, PC gas swelling property, and step embedding property as optical characteristics were performed. The results are shown in Table 7.

<Coating property> The obtained adhesive was applied to a release paper by a comma coater at a coating speed of 3 m/min, and visually evaluated by the following criteria.

○: The surface of the adhesive layer was smooth. That is, there are no streaks, dents, and the like, and the coated surface is smooth.

×: The surface of the adhesive layer is not smooth or has pinholes.

<Adhesive force> The release paper on one side of the obtained adhesive sheet was peeled off, and the adhesive layer was adhered to a PET film (A-4300, manufactured by Toyobo Co., Ltd., thickness: 100 μm), and then cut into a width of 25 mm × a length of 100 mm. Made out Adhesive sheets for testing. The test was peeled off from the release sheet of the adhesive sheet, and the adhesive layer was adhered to a glass plate (thickness: 0.4 mm) in an environment of 23 ° C to 50% RH, followed by further pressurization according to JIS Z-0237 with a roller. Adhesive. After 24 hours from the pressure bonding, the peel strength (peeling angle of 180°, peeling speed of 300 mm/min, unit of N/25 mm width) was measured by a universal tensile tester.

<Flame resistance and peeling resistance>

The release paper on one side of the obtained adhesive sheet was peeled off, and the adhesive layer was adhered to a PET film (A-4300, manufactured by Toyobo Co., Ltd., thickness: 100 μm), and then cut into a width of 100 mm × a length of 100 mm to prepare a test. Use adhesive sheets. This test was peeled off from the release sheet of the adhesive sheet, and the adhesive layer was adhered to the glass plate, and then left in an environment of 85 ° C for 240 hours. Subsequently, after cooling in an environment of 23 ° C to 50% RH for 24 hours, the occurrence of bubbles in the adhesive layer and the floating or peeling of the adhesive sheet were visually evaluated under the following conditions.

○: No bubbles, floating, and peeling were observed at all.

△: A small amount of bubbles, floating and peeling were found.

×: A large amount of bubbles, floating and peeling were found.

<Transparency> The release paper on one side of the obtained adhesive sheet was peeled off, and the adhesive layer was adhered to a PET film (A-4300, manufactured by Toyobo Co., Ltd., thickness: 100 μm), and then cut into a width of 25 mm × a length of 100 mm. A test adhesive sheet was prepared.

Peel off the release sheet of the test adhesive sheet, ring at 23 ° C - 50% RH In the environment, a laminator was attached to the glass plate, and then HAZE was measured. In addition, HAZE was measured using a Turbidimeter NDH5000W manufactured by Nippon Denshoku Industries Co., Ltd. The evaluation criteria are as follows.

○: HAZE is less than 1.0 (good transparency).

×: HAZE is 1.0 or more (poor transparency).

<Adaptability to polarizing plate>

1. Preparation of samples

A polarizing film of a multilayer structure in which both sides of a polyvinyl alcohol (PVA)-based polarizer are sandwiched between a triethylenesulfonyl cellulose-based protective film (hereinafter referred to as a "TAC film"), and one side thereof is obtained. Adhesive layer after peeling off the release paper on one side of the adhesive sheet is adhered. Thus, a laminate A composed of "release paper/adhesive layer/TAC film/PVA/TAC film" was obtained.

Subsequently, the laminate A was cut into a size of 150 mm × 80 mm, and after releasing the release paper, it was adhered to both sides of a flat glass having a thickness of 1.1 mm by a laminator, and the absorption axes of the respective polarizing plates were perpendicularly intersected. Subsequently, the glass plate to which the laminate was adhered was held in an autoclave at 50 ° C and 5 atmospheres for 20 minutes, thereby bringing the laminate into close contact with the glass plate, thereby obtaining a laminate and a glass plate. Laminate B for evaluation.

2. Heating evaluation

After the obtained laminate B for evaluation was allowed to stand in an environment of 120 ° C for 1,000 hours, the laminate B for evaluation was visually observed to confirm the presence or absence of floating and peeling. Further, light was transmitted through the evaluation laminate B, and light leakage (also referred to as "whitening") from the evaluation laminate B was visually confirmed.

3. Heating and humidification evaluation

The laminate B for evaluation was allowed to stand in an environment of 80° C. to 90% RH for 1000 hours, and then the laminate B for evaluation was visually observed to confirm the presence or absence of floating and peeling. Further, light was transmitted through the evaluation laminate B, and light leakage (also referred to as "whitening") from the evaluation laminate B was visually confirmed.

4. Evaluation criteria

The heating evaluation, heating, and humidification evaluation were all evaluated by the following criteria.

◎: There is no floating, peeling and whitening at all, and the performance is excellent.

○: A small amount of floating, peeling, and whitening appeared, and there was no problem in practical use.

△: A large amount of floating, peeling, and whitening appeared, and there was a problem in practical use.

×: The whole appearance of floating, peeling, and whitening is not practical.

<Repeelability (reworkability)>

The obtained laminate A was cut into a size of 25 mm × 150 mm, and after releasing the release paper, it was adhered to a flat glass having a thickness of 1.1 mm by a laminator. Subsequently, it was kept in an autoclave at 50 ° C and 5 atmospheres for 20 minutes to be brought into close contact with the glass plate. After the test piece was allowed to stand in an environment of 23 ° C to 50% RH for one week, a 180° peel test of peeling the laminate A from the test piece at a speed of 180 degrees and 300 mm/min was performed. Dark spots generated by the adhesive remaining on the surface of the peeled glass were visually observed and evaluated by the following criteria.

○: There is no dark spot at all, and the performance is excellent.

△: A small amount of dark spots can be seen, and there is no problem in practical use.

×: The adhesive layer remains on the glass surface and is not practical.

<non-corrosive>

The release paper on one side of the obtained adhesive sheet was peeled off, and the adhesive layer was adhered to a PET film (A-4300, manufactured by Toyobo Co., Ltd., thickness: 100 μm), and then cut into a width of 40 mm × a length of 100 mm to prepare a test. Use adhesive sheets.

The release paper for peeling test adhesive sheets was adhered to a transparent conductive film of a film (width 40 mm × length 160 mm) on which an ITO transparent conductive film was formed by a laminator in a 23 ° C - 50% RH atmosphere. Thus, a test sample was obtained. The test sample was allowed to stand in an environment of 85 ° C - 90% RH for 1000 hours, and the resistance value immediately after the adhesion and the resistance value after the placement were measured, and the corrosion of the transparent conductive film was performed according to the rate of change of the resistance value before and after the placement. Evaluation. Further, the resistance value was measured using LORESTA GP (MCP-T600 type) manufactured by Mitsubishi Chemical Corporation. The evaluation criteria are as follows.

○: The rate of change of the resistance value was less than 150%, and the non-corrosiveness was good.

×: The rate of change of the resistance value is 150% or more, and the non-corrosiveness is poor.

<non-whitening>

The release paper on one side of the obtained adhesive sheet was peeled off, and the adhesive layer was adhered to a PET film (A-4300, manufactured by Toyobo Co., Ltd., thickness: 100 μm), and then cut into a width of 25 mm × a length of 80 mm to prepare a test. Use adhesive sheets. Subsequently, after peeling off the release paper of the test adhesive sheet, the same transparency was formed by laminating in a 23 ° C - 50% RH environment with a laminator. The film of the conductive film (width 40 mm × length 160 mm) on the transparent conductive film. It was allowed to stand in an environment of 85 ° C - 90% RH for 1000 hours, and was measured after cooling at 23 ° C - 50% RH for 3 hours. In addition, HAZE was measured using a Turbidimeter NDH5000W manufactured by Nippon Denshoku Industries Co., Ltd. The evaluation criteria are as follows.

◎: HAZE is less than 1.2, and it is excellent in non-whitening property.

○: HAZE is 1.2 or more and less than 8.0, and non-whitening property is practically not problematic.

×: HAZE is at least 8.0, and the non-whitening property is poor.

<ease evaluation>

The release paper on one side of the obtained adhesive sheet was peeled off, and the adhesive layer was adhered to a PET film (A-4300, manufactured by Toyobo Co., Ltd., thickness: 100 μm), and then cut into a width of 25 mm × a length of 100 mm to prepare a test. Use adhesive sheets. Subsequently, the test release adhesive sheet was adhered to a polycarbonate (PC) plate having a thickness of 5 mm. Subsequently, it was applied at a pressure of 0.5 MPa in an environment of 50 ° C for 20 minutes to prepare a test piece in which a PET film/adhesive layer/PC board was laminated in this order. The test piece was placed in an oven at 80 ° C for 24 hours. Subsequently, the state of the interface between the adhesive layer and the PC board was visually observed after standing for 24 hours in an environment of 23 ° C, and was evaluated by the following criteria.

◎: The state of the interface did not change, and the performance was excellent.

○: A small amount of bubbles or floating of the adhesive layer appeared in the interface, and there was no problem in practical use.

×: A large amount of bubbles or floating layer of the adhesive layer appear in the interface, and may not practical.

<step difference followability>

The release paper on one side of the obtained adhesive sheet was peeled off, and the adhesive layer was adhered to a PET film (A-4300, manufactured by Toyobo Co., Ltd., thickness: 100 μm), and then cut into a width of 25 mm × a length of 100 mm to prepare a test. Use adhesive sheets.

On the other hand, a line pattern of silver ink having a line width of 1 cm, a line interval of 1 cm, and a thickness of 10 μm was printed on a separately prepared PET film by a screen printer.

Subsequently, in a 23 ° C - 50% RH environment, the release paper of the test adhesive sheet was peeled off and then adhered to the line pattern with a laminator. Subsequently, it was further treated in an autoclave at 50 ° C - 0.5 MPa for 20 minutes, and further placed in a 23 ° C - 50% RH environment for 24 hours, and then whether the adhesive layer can follow the step of the line pattern. It was visually observed and evaluated using the following criteria.

◎: After pasting with a laminator, the step is then embedded by the adhesive layer.

○: After the autoclave treatment, the step difference was then embedded by the adhesive layer.

△: After 24 hours of autoclaving, the step was embedded by the adhesive layer.

×: Even after 24 hours of autoclaving, the step difference was not embedded by the adhesive layer.

As shown in Table 7, Comparative Examples 1 to 19 did not satisfy coating properties, adhesion, All properties of foaming resistance, peeling resistance, transparency, heat resistance, moist heat resistance, removability, non-corrosiveness, wet heat whitening resistance, PC gas swelling resistance, and step difference embedding property.

On the other hand, Examples 1 to 35 have excellent coatability, adhesion, foaming/peeling resistance, transparency, and heat resistance, moist heat resistance, re-peelability, non-corrosiveness, and moisture-resistant whitening. Excellent results were obtained in terms of properties, resistance to PC gas expansion, and step difference embedding.

The adhesive and the adhesive sheet of the present invention not only have excellent coatability, adhesiveness, foaming/peeling resistance, transparency, but also high non-corrosiveness, moisture and heat blush resistance, and PC gas swell resistance. It is suitable for adhesion of optical members such as applications for direct adhesion and fixation on metal films such as displays or touch screens.

Claims (6)

An adhesive comprising an acrylic copolymer (A), a polyisocyanate curing agent (B), and a decane coupling agent (C); and the acrylic copolymer (A) has a SP value of 8 or more and less than 9.00 by radical polymerization. 20 to 90% by weight of an alkyl group-containing ethylenically unsaturated monomer (A1) and 10 to 80% by weight of a polar group-containing ethylenically unsaturated monomer (A2) having an SP value of 9.00 or more and 15 or less. And a polymer having a weight average molecular weight of 200,000 to 1,000,000; the above ethylenically unsaturated monomer (A1) having an alkyl group does not include a monomer having a bicyclic ring structure and an olefinic double bond; The ethylenically unsaturated monomer (A2) is: (1) selected from the group consisting of a hydroxyl group-containing ethylenically unsaturated monomer (a1), a mercaptoamine group-containing ethylenically unsaturated monomer (a2), and an amine group-containing One of the group consisting of the ethylenically unsaturated monomer (a3) and the nitrile group-containing ethylenically unsaturated monomer (a4); or (2) having an ethylenically unsaturated monomer selected from the group consisting of a guanamine group ( A2), one of a group consisting of an amine group-containing ethylenically unsaturated monomer (a3) and a nitrile group-containing ethylenically unsaturated monomer (a4), and a hydroxyl group-containing ethylenic group Unsaturated monomer (A1); and homopolymer glass transition temperature (Tg) of less than -40 ℃ 120 ℃. The adhesive according to claim 1, wherein the acrylic copolymer (A) has a SP value of 8 or more and less than 9.00 by radical polymerization. The alkyl group-containing ethylenically unsaturated monomer (A1) is formed in an amount of 40 to 80% by weight, and the polar group-containing ethylenically unsaturated monomer (A2) having an SP value of 9.00 or more and 15 or less is formed in an amount of 20 to 60% by weight. The adhesive according to claim 1 or 2, wherein the polyisocyanate hardener (B) is one or more compounds selected from the group consisting of aromatic aliphatic polyisocyanates, aliphatic polyisocyanates, and alicyclic polyisocyanates. , or a modification of these compounds. The adhesive according to claim 1 or 2, wherein the decane coupling agent (C) has an alkoxy group and an alicyclic epoxy group, or only has an alkoxy group as a reactive functional group. An adhesive sheet having at least an adhesive layer formed of the adhesive according to any one of claims 1 to 4. A display having at least an adhesive layer formed of the adhesive according to any one of claims 1 to 4.