KR20180091892A - Pressure-sensitive adhesive composition - Google Patents

Abstract

[PROBLEMS] To provide a pressure-sensitive adhesive composition capable of forming a pressure-sensitive adhesive layer having excellent durability even under severe endurance conditions.
A pressure-sensitive adhesive composition comprising a (meth) acrylic resin (A), a crosslinking agent (B) and a silane compound (C), wherein the (meth) acrylic resin (A) (meth) acrylate represented by the following formula (a2), and the crosslinking agent (B) is an adduct of a tolylene diisocyanate compound and / or a tolylene diisocyanate compound with a polyhydric alcohol compound .

Description

Pressure-sensitive adhesive composition

The present invention relates to a pressure-sensitive adhesive composition useful for forming a pressure-sensitive adhesive layer having excellent durability in an optical film or the like provided with a pressure-sensitive adhesive layer used for a liquid crystal display or the like.

An optical film typified by a polarizing plate in which a transparent resin film is laminated on one surface or both surfaces of a polarizer is widely used as an optical member constituting an image display device such as a liquid crystal display device. An optical film such as a polarizing plate is often used by being bonded to another member (for example, a liquid crystal cell or the like in a liquid crystal display device) through a pressure-sensitive adhesive layer (see Patent Document 1). Therefore, as an optical film, an optical film having a pressure-sensitive adhesive layer having a pressure-sensitive adhesive layer formed on one side thereof in advance is known.

Patent Document 1: JP-A-2010-229321

2. Description of the Related Art In recent years, liquid crystal display devices have been developed for use in mobile devices typified by smart phones and tablet-type terminals, and in automotive devices represented by car navigation systems. In such an application, there is a possibility that the device is exposed to harsh environments as compared with the conventional use for an indoor TV, so that improvement of the durability of the device is a problem.

Durability is similarly demanded in an optical film having a pressure-sensitive adhesive layer constituting a liquid crystal display or the like. That is, the pressure-sensitive adhesive layer contained in the liquid crystal display device may be put under an environment of high temperature or high temperature and high humidity, or may be placed under an environment where high temperature and low temperature are repeated. In the optical film having the pressure-sensitive adhesive layer, It is required to be able to suppress problems such as lifting and peeling off at the interface with the optical member and foaming of the pressure-sensitive adhesive layer, and it is also required that the optical characteristics are not deteriorated. In particular, when the optical film is a polarizing plate, the pressure-sensitive adhesive layer needs to have a higher durability performance than a general optical film due to strong shrinkage stress under a high temperature environment. The durability required of the above-described pressure sensitive adhesive layer becomes very strict recently.

Accordingly, an object of the present invention is to provide a pressure-sensitive adhesive composition capable of forming a pressure-sensitive adhesive layer having excellent durability even under such severe endurance conditions.

Means for Solving the Problems The present inventors have intensively studied in order to solve the above-mentioned problems and have completed the present invention.

That is, the present invention includes the following.

[1] A pressure-sensitive adhesive composition comprising a (meth) acrylic resin (A), a crosslinking agent (B) and a silane compound (C)

The (meth) acrylic resin (A)

(Wherein n represents an integer of 1 to 4, A ¹ represents a hydrogen atom or an alkyl group, X ¹ represents a methylene group which may have a substituent, and when n is 2 or more, the substituents may be the same or different good)

(Meth) acrylate represented by the following formula (a2) and a structural unit derived from a hydroxyl group-containing

(Wherein m represents an integer of 5 or more, A ² represents a hydrogen atom or an alkyl group, X ² represents a methylene group which may have a substituent, and the above substituents may be the same or different)

(Meth) acrylate-containing structural unit represented by the general formula

Wherein the crosslinking agent (B) is an addition of a tolylene diisocyanate compound and / or a tolylene diisocyanate compound with a polyhydric alcohol compound.

The proportion of the structural unit derived from a hydroxyl group-containing (meth) acrylate represented by the formula (a1) is 1.5 to 4.5 parts by weight based on 100 parts by weight of all the constituent units constituting the [2] (meth) acrylic resin, The pressure-sensitive adhesive composition according to [1], wherein the proportion of the structural unit derived from a hydroxyl group-containing (meth) acrylate represented by the formula (a2) is 0.25 to 1.0 part by weight.

[3] The (meth) acrylic resin is a resin composition comprising a constituent unit derived from an alkyl acrylate (a3-1) having a glass transition temperature of the homopolymer of lower than 0 ° C and a constituent unit derived from an alkyl acrylate having a glass transition temperature of 0 ° C or higher (a3- The pressure-sensitive adhesive composition according to [1] or [2], which comprises a structural unit derived from an alkyl acrylate (a3) containing a structural unit derived from 2)

[4] A resin composition comprising a structural unit derived from an alkyl acrylate (a3-1) having a glass transition temperature of less than 0 ° C and a structural unit derived from an alkyl acrylate (a3-2) having a glass transition temperature of 0 ° C or higher (Weight ratio) of (a3-1) / (a3-2) = 20/80 to 95/5.

The pressure-sensitive adhesive composition according to any one of [1] to [4], wherein the weight average molecular weight of the (meth) acrylic resin is 6.0 × 10 ^{5 to} 2.5 × 10 ⁶ in terms of polystyrene.

[6] The pressure-sensitive adhesive composition according to any one of [1] to [5], wherein the ratio of the crosslinking agent (B) is 0.01 to 10 parts by weight based on 100 parts by weight of the (meth) acrylic resin (A).

[7] The silane compound (C) is represented by the following formula (c1)

(Wherein B represents an alkanediyl group having 1 to 20 carbon atoms or a divalent alicyclic hydrocarbon group having 3 to 20 carbon atoms, and the alkanediyl group and -CH ₂ - constituting the alicyclic hydrocarbon group are -O- or -O-, good which may be substituted by CO-, R ¹ represents an alkyl group having 1 to 5 carbon atoms, R ^2, R ^3, R ^4, R ⁵ and R ⁶ is alkoxy of 1 to 5 carbon atoms or an alkyl group having 1 to 5 carbon atoms are each independently Lt; / RTI >

The pressure-sensitive adhesive composition according to any one of [1] to [6], wherein the pressure-sensitive adhesive composition is a silane compound.

R ¹ , R ² , R ³ , R ⁴ , R ⁵ and R ⁶ are each independently a C 1 -C 5 alkyl group, A pressure-sensitive adhesive composition according to [7], wherein the pressure-sensitive adhesive composition is an alkoxy group having 1 to 5 carbon atoms.

[9] The pressure-sensitive adhesive composition according to any one of [1] to [8], wherein the proportion of the silane compound (C) is 0.01 to 10 parts by weight based on 100 parts by weight of the (meth) acrylic resin (A).

[10] The pressure-sensitive adhesive composition according to any one of [1] to [9], wherein the pressure-sensitive adhesive formed from the pressure-sensitive adhesive composition has a gel fraction of 50 to 95%.

The adhesive force of the pressure-sensitive adhesive layer after 24 hours under the conditions of a temperature of 23 ° C. and a relative humidity of 50% is preferably from 0.5 to 5 g / cm 2 at a stripping rate of 300 mm / min, Wherein the pressure-sensitive adhesive layer has a thickness of 10 N / 25 mm.

[12] The pressure-sensitive adhesive composition according to any one of [1] to [11], which is used for forming a pressure-sensitive adhesive layer to be laminated on an optical film.

The pressure-sensitive adhesive composition of the present invention can form a pressure-sensitive adhesive layer having excellent durability even under severe durability conditions.

1 is a schematic sectional view showing an example of an optical film having a pressure-sensitive adhesive layer formed from the pressure-sensitive adhesive composition according to the present invention.
2 is a schematic cross-sectional view showing an example of the layer structure of the polarizing plate.
3 is a schematic cross-sectional view showing another example of the layer structure of the polarizing plate.
4 is a schematic cross-sectional view showing an example of an optical laminate including an optical film having a pressure-sensitive adhesive layer formed from the pressure-sensitive adhesive composition according to the present invention.
5 is a schematic cross-sectional view showing an example of an optical laminate including an optical film having a pressure-sensitive adhesive layer formed from the pressure-sensitive adhesive composition according to the present invention.
6 is a schematic sectional view showing still another example of the optical laminate including the optical film having the pressure-sensitive adhesive layer formed from the pressure-sensitive adhesive composition according to the present invention.
7 is a schematic cross-sectional view showing another example of an optical laminate including an optical film having a pressure-sensitive adhesive layer formed from the pressure-sensitive adhesive composition according to the present invention.
8 is a schematic cross-sectional view showing another example of the optical laminate including the optical film having the pressure-sensitive adhesive layer formed from the pressure-sensitive adhesive composition according to the present invention.

[1] Pressure-sensitive adhesive composition

The pressure-sensitive adhesive composition of the present invention comprises a (meth) acrylic resin (A), a crosslinking agent (B), and a silane compound (C).

[1-1] (meth) acrylic resin (A)

(Meth) acrylic resin (A) is a polymer or copolymer containing as a main component (preferably, 50% by weight or more) a constitutional unit derived from a (meth) acrylic monomer and satisfies the following formulas (a1) (Meth) acrylate-containing structural units represented by the general formula (1) shown below.

(Wherein n represents an integer of 1 to 4, A ¹ represents a hydrogen atom or an alkyl group, X ¹ represents a methylene group which may have a substituent, and when n is 2 or more, the substituents may be the same or different good)

(Wherein m represents an integer of 5 or more, A ² represents a hydrogen atom or an alkyl group, X ² represents a methylene group which may have a substituent, and the above substituents may be the same or different)

That is, since the (meth) acrylic resin (A) of the present invention has a hydroxyalkyl group having a different carbon chain length (n and m) on the side chain, the pressure-sensitive adhesive layer formed of the pressure- Lt; RTI ID = 0.0 > crosslinked < / RTI > By optimizing the cross-linking density, it is possible to form a pressure-sensitive adhesive layer having an excellent balance between hardness and softness (or having an optimum hardness), thereby improving durability and, even at high temperature, peeling (or lifting) The foaming can be effectively suppressed. Moreover, even when a strong shrinkage stress is generated, the pressure-sensitive adhesive layer can relieve the stress effectively, so that whitening of the optical film (for example, deflection plate) due to shrinkage can be prevented. Further, the reworkability (peelability) can be improved by optimizing the crosslinking density. The term "durability" as used herein refers to a property of suppressing lifting and peeling at the interface between the pressure-sensitive adhesive layer and the optical member adjacent to the pressure-sensitive adhesive layer in an environment in which high temperature and low temperature are repeated under a high temperature and high humidity environment under a high temperature environment (Which may be referred to as " peel resistance ") capable of suppressing problems such as foaming of the pressure-sensitive adhesive layer and the like. In the present invention, the cohesive failure property refers to a property capable of suppressing cohesive failure (or tearing) of the pressure-sensitive adhesive layer.

In the formulas (a1) and (a2), X ¹ and X ² represent a methylene group which may have a substituent. Examples of the substituent include a halogen atom (a fluorine atom, a chlorine atom, a bromine atom and an iodine atom), an alkyl group (such as a methyl group, an ethyl group, a propyl group, an isopropyl group, a butyl group, , A C _1-10 alkyl group such as a hexyl group, preferably a C _1-6 alkyl group, more preferably a C _1-3 alkyl group), a cycloalkyl group (cyclopentyl group, cyclohexyl group, etc.) (For example, benzyl group, etc.), an alkoxy group (for example, a C _1-4 alkoxy group such as a methoxy group or an ethoxy group), a polyoxyalkylene group (for example, a dioxyethylene group, etc.) ) cycloalkoxy group (e.g., cyclohexyloxy group, etc. C _5-10 cycloalkyl, aryloxy, etc.), an aryloxy group (e.g. phenoxy group, etc.), aralkyl kilok group (e.g. benzyloxy group, etc.), alkylthio groups (e.g. A C _1-4 alkylthio group such as a methylthio group, an ethylthio group, etc.), a cycloalkylthio group (E.g., benzylthio group), an acyl group (e.g., acetyl group and the like), a nitro group, a cyano group, and the like can be given . Of these, a halogen atom, an alkyl group, an alkoxy group, an aryloxy group and the like are preferable, and an alkyl group (for example, methyl group, ethyl group and the like) is particularly preferable.

A ¹ and A ² each represent a hydrogen atom or an alkyl group, and the alkyl group may be an alkyl group (preferably a methyl group or the like) exemplified for X ¹ and X ² .

In the formula (a1), n represents an integer of 1 to 4, preferably an integer of 1 to 3, more preferably 2. In the formula (a2), m is an integer of 5 or more (e.g., an integer of 5 to 20), preferably 5 to 15 (e.g., an integer of 5 to 11), more preferably 5 to 9 , Especially 5). Further, m may be an even number (for example, 6, 8, 10, 12, etc.) of 5 or more, or an odd number of 5 or more (for example, 5, 7, 9,

Specific examples of the hydroxyl group-containing (meth) acrylate (a1) include 1-hydroxymethyl (meth) acrylate, 1-hydroxyethyl (meth) acrylate, 1-hydroxyheptyl 1-hydroxyC _1-8 alkyl (meth) acrylate such as 1-hydroxybutyl and 1-hydroxypentyl (meth) acrylate; (Meth) acrylate, 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 2-hydroxybutyl Of (meth) acrylic acid 2-hydroxyC _2-9 alkyl; (Meth) acrylate, 3-hydroxybutyl (meth) acrylate, 3-hydroxybutyl (meth) acrylate, 3-hydroxypentyl Of (meth) acrylic acid 3-hydroxyC _3-10 alkyl; (Meth) acrylate, 4-hydroxybutyl (meth) acrylate, 4-hydroxypentyl (meth) acrylate, 4-hydroxyhexyl Of (meth) acrylic acid 4-hydroxyC _4-11 alkyl; Chloro-2-hydroxypropyl (meth) acrylate, 3-chloro-2-hydroxypropyl (meth) acrylate and 2-hydroxy-3-phenoxypropyl (meth) acrylate. Of these, hydroxy-containing (meth) acrylates such as 2-hydroxyethyl acrylate, 2-hydroxypropyl (meth) acrylate and 2-hydroxybutyl (meth) acrylate, wherein n is 2; (Meth) acrylate such as 3-hydroxypropyl (meth) acrylate, 3-hydroxybutyl (meth) acrylate and 3-hydroxypentyl (meth) acrylate is preferable. (Meth) acrylate in which n is 2 are preferable, and among them, 2-hydroxyethyl (meth) acrylate is preferable.

Specific examples of the hydroxyl group-containing (meth) acrylate (a2) include 5-hydroxypentyl (meth) acrylate, 5-hydroxyhexyl (meth) acrylate, 5-hydroxyheptyl 5-hydroxyC _5-12 alkyl (meth) acrylate such as 5-hydroxyoctyl and 5-hydroxynonyl (meth) acrylate; (Meth) acrylate, 6-hydroxyhexyl (meth) acrylate, 6-hydroxyheptyl (meth) acrylate, 6-hydroxyoctyl Of (meth) acrylic acid 6-hydroxyC _6-13 alkyl; (Meth) acrylate, 7-hydroxyoctyl (meth) acrylate, 7-hydroxyoctyl (meth) acrylate, 7-hydroxynonyl (Meth) acrylic acid 7-hydroxyC _7-14 alkyl, such as (Meth) acrylate, 8-hydroxyoctyl (meth) acrylate, 8-hydroxynonyl (meth) acrylate, 8-hydroxydecyl of the yarn, such as (meth) acrylic acid 8-hydroxy C _8-15 alkyl; (Meth) acrylic acid 9-hydroxydecyl, (meth) acrylic acid 9-hydroxydecyl, (meth) acrylic acid 9- (Meth) acrylic acid 9-hydroxyC _9-16 alkyl such as tridecyl; (Meth) acrylic acid 10-hydroxydodecyl, (meth) acrylic acid 10-hydroxydecyl, (meth) acrylic acid 10-hydroxydodecyl, (Meth) acrylic acid 10-hydroxyC _10-17 alkyl, such as (Meth) acrylate, 11-hydroxydecyl (meth) acrylate, 11-hydroxydodecyl (meth) acrylate, 11-hydroxytridecyl 10-hydroxyC _11-18 alkyl (meth) acrylate such as hydroxypentadecyl; 12-hydroxy C _12-19 alkyl (meth) acrylate such as (meth) acrylic acid 12-hydroxydecyl, (meth) acrylic acid 12-hydroxytridecyl, and (meth) acrylic acid 12-hydroxytetradecyl; (Meth) acrylic acid 13-hydroxy-pentadecyl (meth) acrylate, 13-hydroxy-tetradecyl (meth) acrylate, 13-hydroxy-pentadecyl, etc. of (meth) acrylic acid 13-hydroxy-C _13-20 alkyl; (Meth) acrylic acid 14-hydroxy-tetradecyl (meth) acrylate, 14-hydroxy-pentadecyl, etc. of (meth) acrylic acid 14-hydroxy-C _14-21 alkyl; (Meth) acrylic acid 15-hydroxy-pentadecyl (meth) acrylate, 15-hydroxy-heptadecyl, etc. of (meth) acrylic acid 15-hydroxy-C _15-22 alkyl and the like. Of these, from the viewpoint of durability, 5-hydroxypentyl (meth) acrylate, 5-hydroxyhexyl (meth) acrylate, 5-hydroxyheptyl (meth) acrylate, 5-hydroxyoctyl (Meth) acrylate having an n of 5 such as 5-hydroxynonyl (meth) acrylate is preferable, and 5-hydroxypentyl (meth) acrylate is particularly preferable.

(Meth) acrylate based on 100 parts by weight of the total structural units constituting the (meth) acrylic resin, the ratio of the structural unit derived from a hydroxyl group-containing (meth) acrylate represented by the formula (a1) is preferably 1.5 to 4.5 parts by weight, The proportion of the structural unit derived from a hydroxyl group-containing (meth) acrylate represented by a2) is preferably 0.25 to 1.0 part by weight. The ratio (weight ratio) of the constitutional unit derived from a hydroxyl group-containing (meth) acrylate represented by the formula (a1) to the constitutional unit derived from a hydroxyl group-containing (meth) acrylate represented by the formula (a2) (A1) / (a2) = 13/1 to 3/1 (e.g., 11/1 to 3/1), more preferably 9/1 to 4/1, and particularly preferably 7/1 to 5/1. Within the above range, it is advantageous in forming an optimum crosslinked structure and the characteristics such as durability can be improved.

The (meth) acrylic resin (A) may contain a constituent unit derived from an alkyl acrylate (a3) and a constituent unit derived from a substituent group containing an alkyl acrylate (a4).

Examples of the alkyl acrylate (a3-1) in which the glass transition temperature (Tg) of the homopolymer is lower than 0 占 폚 in the alkyl acrylate (a3) include ethyl acrylate, n- and i- Butyl acrylate, n-pentyl acrylate, n- and i-hexyl acrylate, n- heptyl acrylate, n- and i-octyl acrylate, 2-ethylhexyl acrylate, n- and i- and linear or branched alkyl acrylates having 2 to 12 carbon atoms in the alkyl group such as n- and i-decyl acrylate and n-dodecyl acrylate. The alkyl acrylate (a3) may be an alkyl acrylate (cycloalkyl acrylate) having an alicyclic structure, but from the viewpoint of followability (or flexibility and adhesiveness) to an optical film, an alkyl acrylate having 2 to 10 carbon atoms, Preferably an alkyl acrylate having 3 to 8 carbon atoms, more preferably an alkyl acrylate having 4 to 6 carbon atoms, especially n-butyl alkyl acrylate. When n-butyl alkyl acrylate is used, the followability can be enhanced, and for example, peeling resistance and the like are advantageous. These alkyl acrylates (a3-1) may be used singly or in combination of two or more.

Examples of the alkyl acrylate (a3-2) having a homopolymer Tg of 0 ° C or higher include methyl acrylate, cycloalkyl acrylate (e.g., cyclohexyl acrylate, isobornyl acrylate), stearyl acrylate, t- And the like, and methyl acrylate is particularly preferable. The use of methyl acrylate can increase the strength and is advantageous, for example, against cohesive failure. These alkyl acrylates (a3-2) may be used alone or in combination of two or more. Further, the Tg of the homopolymer of alkyl acrylate can be referenced, for example, from literature data such as POLYMER HANDBOOK (Wiley-Interscience).

From the viewpoint of the durability and reworkability of the pressure-sensitive adhesive layer, the proportion of the constituent unit derived from the alkyl acrylate in the (meth) acrylic resin (A) is preferably 100 parts by weight or less, (For example, 50 to 98 parts by weight), preferably 60 parts by weight or more (for example 70 to 95 parts by weight), more preferably 70 parts by weight or more (for example, 80 to 90 parts by weight )to be.

When the alkyl acrylate having a Tg of the homopolymer of less than 0 占 폚 and the alkyl acrylate having a Tg of 0 占 폚 or more of the homopolymer are used in combination, it is possible to achieve both cohesive failure resistance and followability (foam resistance and peel resistance) Durability against dimensional changes of the polarizing plate can be improved.

The ratio (weight ratio) of the constituent unit derived from the alkyl acrylate (a3-1) having a glass transition temperature of the homopolymer of lower than 0 ° C and the constituent unit derived from the alkyl acrylate (a3-2) having a glass transition temperature of 0 ° C or higher is (a3 -1 / (a3-2) = 20/80 to 95/5 (e.g. 30/70 to 90/10), preferably 40/60 to 85/15, more preferably 55/45 to 75/25 to be. Within the above range, the durability can be further improved. As the proportion of the constitutional unit derived from the alkyl acrylate (a3-1) having a glass transition temperature of lower than 0 占 폚 is larger, followability is improved. As the proportion of the constituent unit derived from the alkyl acrylate (a3-2) having a glass transition temperature of 0 ° C or higher is larger, the coagulation failure resistance is improved.

Examples of the substituent-containing alkyl acrylate (a4) include alkyl acrylates in which a substituent is introduced into the alkyl group in the alkyl acrylate (a3-1) (in which the hydrogen atom of the alkyl group is substituted by a substituent). This substituent may be, for example, an aryl group (phenyl group, etc.), an aryloxy group (phenoxy group), an alkoxy group (such as methoxy group or ethoxy group) Examples of the substituent group-containing alkyl acrylate (a3-3) include alkoxyalkyl acrylates (e.g., 2-methoxyethyl acrylate, ethoxymethyl acrylate and the like), aryloxyalkyl acrylates (such as phenoxyethyl acrylate) Aryloxypolyalkylene glycol monoacrylate, polyalkylene glycol monoacrylate, and the like. These alkyl acrylates (a3-3) may be used alone or in combination of two or more. By including an alkyl acrylate containing an aromatic ring such as an aryl group or an aryloxy group, it is possible to improve the phenomenon that the polarizing plate is whitened out during the durability test. The alkylene group of the aryloxypolyalkylene glycol monoacrylate and the polyalkylene glycol monoacrylate is preferably a C _1-6 alkylene group (preferably an ethylene group or the like) such as a methylene group, an ethylene group or a propylene group And the repeating unit of the oxyalkylene group may be, for example, 2 to 7, preferably 2 to 5 (particularly 2) from the viewpoint of the durability of the pressure-sensitive adhesive layer formed of the pressure-sensitive adhesive composition. In the present invention, since an optimal crosslinking structure (or crosslinking density) can be formed by including the (meth) acrylic resin (A) and the crosslinking agent (B) described later in the pressure- Even if it is relatively small, it exhibits good reworkability. Specific examples thereof include phenoxydi to hepta C _1-3 alkylene glycol-acrylate such as phenoxy diethylene glycol acrylate, di-hepta C _1-3 alkylene-monoacrylate such as diethylene glycol monoacrylate, etc. .

The proportion of the constituent unit derived from the substituent group-containing alkyl acrylate is, for example, 0 to 30 parts by weight (for example, 1 to 25 parts by weight) relative to 100 parts by weight of the total constituent units constituting the (meth) acrylic resin (A) Is 3 to 20 parts by weight, more preferably 5 to 15 parts by weight.

The (meth) acrylic resin (A) is a copolymer of the monomer (a5) other than the hydroxyl group-containing (meth) acrylate (a1) and the monomer (a2), the alkyl acrylate (a3) And may contain a derived constituent unit. The other monomers may be used alone or in combination of two or more. As the other monomer (a5), a monomer (a5-1) having a polar functional group other than a hydroxyl group, an acrylamide monomer (a5-2), methacrylate (methacrylic acid ester) (a5-3), methacrylamide (A5-4), a styrene monomer (a5-5), a vinyl monomer (a5-6), and a plurality of (meth) acryloyl group-containing monomers (a5-7) in the molecule.

Examples of the monomer (a5-1) having a polar functional group other than the hydroxyl group include a (meth) acrylate having a substituent such as a carboxyl group, a substituted or unsubstituted amino group, and a heterocyclic group such as an epoxy group. Specific examples thereof include acryloylmorpholine, vinylcaprolactam, N-vinyl-2-pyrrolidone, vinylpyridine, tetrahydrofurfuryl (meth) acrylate, caprolactone-modified tetrahydrofurfuryl acrylate, Monomers having a heterocyclic group such as epoxy cyclohexylmethyl (meth) acrylate, glycidyl (meth) acrylate, and 2,5-dihydrofuran; Monomers having substituted or unsubstituted amino groups such as aminoethyl (meth) acrylate, N, N-dimethylaminoethyl (meth) acrylate and dimethylaminopropyl (meth) acrylate; A monomer having a carboxyl group such as (meth) acrylic acid, maleic acid, maleic anhydride, fumaric acid, crotonic acid, carboxyalkyl (meth) acrylate (such as carboxyethyl (meth) acrylate, carboxypentyl . These monomers may be used alone or in combination of two or more. Further, from the viewpoint of preventing deterioration of the releasability of the separable film laminated on the pressure-sensitive adhesive layer, it is preferable that substantially no constituent unit derived from a monomer having an amino group is contained. Here, substantially no inclusion means that the amount is less than 1.0 part by weight based on 100 parts by weight of all the constituent units constituting the (meth) acrylic resin (A).

In the present invention, even if it does not contain a constituent unit derived from a monomer having a carboxyl group (which is a constituent unit derived from a carboxyl group-containing (meth) acrylate), which is thought to increase the ITO corrosion resistance, it exhibits high durability and therefore has both durability and ITO corrosion resistance .

On the other hand, when a structural unit derived from a monomer having a carboxyl group [a structural unit derived from a carboxyl group-containing (meth) acrylate]] is contained, durability can be further improved. In the present invention, since the durability can be effectively improved even when the proportion of the constituent unit derived from a carboxyl group-containing (meth) acrylate is small, it is possible to improve the durability while suppressing the corrosion of the ITO.

The proportion of the constituent unit derived from a carboxyl group-containing (meth) acrylate is, for example, not more than 5.0 parts by weight (for example, 0 to 3 parts by weight), preferably 1.0 part by weight (For example, 0.001 to 0.5 part by weight), more preferably not more than 0.3 part by weight (for example, 0.005 to 0.3 part by weight), particularly preferably not more than 0.2 part by weight For example, 0.01 to 0.2 parts by weight), particularly 0.15 parts by weight or less (for example, 0.05 to 0.15 parts by weight). If it is not more than the upper limit value, the ITO corrosion resistance can be suppressed, and if it is not less than the lower limit value, the durability can be improved.

Examples of the acrylamide monomer (a5-2) include N-methylol acrylamide, N- (2-hydroxyethyl) acrylamide, N- (3- hydroxypropyl) acrylamide, N- Butyl acrylate, N, N-dimethylacrylamide, N, N-diethylacrylamide, N-isopropyl (meth) acrylate, N- Acrylamide, N- (2-oxo-1-imidazolidinyl) ethyl (meth) acrylate, N- (Methoxymethyl) acrylamide, N- (ethoxymethyl) acrylamide, N- (propoxymethyl) acrylamide, N- Acrylamides such as N- (1-methylethoxymethyl) acrylamide, N- (1-methylpropoxymethyl) acrylamide and N- (2-methylpropoxymethyl) ], N- (butoxymethyl) Acrylamide, N- (2-ethoxyethyl) acrylamide, N- (2-methoxyethyl) Acrylamide, N- [2- (2-methylpropoxy) ethyl] acrylamide, N- [2- Ethyl] acrylamide [alias: N- (2-isobutoxyethyl) acrylamide], N- (2-butoxyethyl) acrylamide, N- [2- (1,1-dimethylethoxy) ethyl] acrylamide Etc. Of these, preferred are N- (methoxymethyl) acrylamide, N- (ethoxymethyl) acrylamide, N- (propoxymethyl) acrylamide, N- (butoxymethyl) Hydroxy-methyl) acrylamide and the like are preferable.

Examples of the methacrylate (methacrylate ester) (a5-3) include methyl methacrylate, ethyl methacrylate, propyl methacrylate, n-butyl methacrylate, n-octyl methacrylate, And the like; branched alkyl methacrylates such as i-butyl methacrylate, 2-ethylhexyl methacrylate, and i-octyl methacrylate; Cyclohexyl methacrylate, isobornyl methacrylate, cyclohexyl methacrylate, dicyclopentyl methacrylate, cyclododecyl methacrylate, methyl cyclohexyl methacrylate, trimethyl cyclohexyl methacrylate, t-butyl cyclohexyl methacrylate, Mono or dicycloalkyl methacrylates such as cyclohexyl phenyl methacrylate; Alkoxyalkyl methacrylates such as 2-methoxyethyl methacrylate and ethoxy methyl methacrylate; And aralkyl methacrylates such as benzyl methacrylate.

Examples of the methacrylamide-based monomer (a5-4) include a methacrylamide-based monomer corresponding to the acrylamide-based monomer described in (a5-2).

Examples of the styrene-based monomer (a5-5) include styrene; Alkylstyrenes such as methylstyrene, dimethylstyrene, trimethylstyrene, ethylstyrene, diethylstyrene, triethylstyrene, propylstyrene, butylstyrene, hexylstyrene, heptylstyrene and octylstyrene; Halogenated styrenes such as fluorostyrene, chlorostyrene, bromostyrene, dibromostyrene, and iodostyrene; Nitrostyrene; Acetyl styrene; Methoxystyrene; Divinylbenzene and the like.

Examples of the vinyl monomer (a5-6) include fatty acid vinyl esters such as vinyl acetate, vinyl propionate, vinyl butyrate, vinyl 2-ethylhexanoate and vinyl laurate; Vinyl halides such as vinyl chloride and vinyl bromide; Vinylidene halides such as vinylidene chloride; Nitrogen-containing aromatic vinyls such as vinylpyridine, vinylpyrrolidone and vinylcarbazole; Conjugated diene monomers such as butadiene, isoprene, and chloroprene; And unsaturated nitriles such as acrylonitrile and methacrylonitrile.

Examples of the monomer (a5-7) having a plurality of (meth) acryloyl groups in the molecule include 1,4-butanediol di (meth) acrylate, 1,6-hexanediol di (meth) acrylate, (Meth) acrylate, ethylene glycol di (meth) acrylate, diethylene glycol di (meth) acrylate, tetraethylene glycol di (meth) acrylate and tripropylene glycol di A monomer having two (meth) acryloyl groups in the molecule; And monomers having three (meth) acryloyl groups in the molecule such as trimethylolpropane tri (meth) acrylate.

From the viewpoint of reworkability of the pressure-sensitive adhesive layer, the (meth) acrylic resin (A) is preferably methacrylic acid such as methacrylate (methacrylic ester) (a5-3), methacrylamide monomer (Or the content) of the constituent unit derived from the monomer is preferably small. That is, the proportion of the structural unit is preferably 10 parts by weight or less, more preferably 5 parts by weight or less, and particularly preferably 1 part by weight or less, based on 100 parts by weight of the total structural units constituting the (meth) acrylic resin (A) Or less.

The proportion of the structural unit derived from the other monomer (a5) is, for example, 0 to 20 parts by weight, preferably 0 to 10 parts by weight, relative to 100 parts by weight of the total structural units constituting the (meth) acrylic resin (A) (E.g., 0.001 to 10 parts by weight), more preferably 0 to 5 parts by weight (e.g., 0.01 to 3 parts by weight).

(Meth) acrylic resin (A) has a weight average molecular weight (Mw) in terms of standard polystyrene by gel permeation chromatography GPC, for example, ^{6.0 × 10 5 ~2.5 × 10 6} ( for example, 8.0 × 10 ⁵ ~2.5 × 10 ⁶ ), Preferably 1.0 x 10 ^{6 to} 2.0 x 10 ⁶ , and more preferably 1.2 x 10 ^{6 to} 1.8 x 10 ⁶ (e.g., 1.3 x 10 ^{6 to} 1.6 x 10 ⁶ ). When the Mw is not more than the upper limit, the pressure-sensitive adhesive composition is advantageous from the viewpoint of coating on the substrate, and if the Mw is not less than the lower limit, it is advantageous for improving the followability of the pressure-sensitive adhesive layer against the dimensional change of the optical film. The molecular weight distribution represented by the ratio (Mw / Mn) of the weight average molecular weight (Mw) to the number average molecular weight (Mn) is usually 2 to 10, preferably 3 to 8, more preferably 4 to 6.

It is also preferable that the (meth) acrylic resin (A) has a single peak in the range of Mw on the discharge curve in GPC in the range of 1.0 × 10 ^{3 to} 2.5 × 10 ⁶ . When the (meth) acrylic resin (A) having a peak number of 1 is used, the durability of the pressure-sensitive adhesive layer is advantageously improved.

The term "having a single peak" in the above range of the obtained discharge curve means that it has only one maximum value in the range of Mw 1.0 × 10 ^{3 to} 2.5 × 10 ⁶ . In the present specification, a peak having an S / N ratio of 30 or more in the GPC discharge curve is defined as a peak. Further, the number of peaks of the GPC discharge curve and the Mw and Mn of the (meth) acrylic resin (A) can be determined by the GPC measurement conditions described in the embodiment section.

When the (meth) acrylic resin (A) is dissolved in ethyl acetate to give a solution having a concentration of 20% by weight, the viscosity at 25 ° C is preferably 20 Pa · s or less, more preferably 0.1 to 7 Pa · s More preferable. When the viscosity is within this range, the pressure-sensitive adhesive composition is advantageous from the viewpoint of coatability when it is applied to a substrate. The viscosity can also be measured by a Brookfield viscometer.

The glass transition temperature (Tg) of the (meth) acrylic resin (A) is, for example, from -60 to 0 캜 (for example, from -50 to -10 캜), preferably from -50 to -20 캜, -20 占 폚 (for example, -40 to -25 占 폚). Within this range, it is advantageous in improving durability. The glass transition temperature can be measured by a differential scanning calorimeter (DSC).

The (meth) acrylic resin (A) can be produced by a known method such as a solution polymerization method, a bulk polymerization method, a suspension polymerization method or an emulsion polymerization method, and a solution polymerization method is particularly preferable. Examples of the solution polymerization method include a method in which a monomer and an organic solvent are mixed, a thermal polymerization initiator is added in a nitrogen atmosphere, and the mixture is stirred for about 3 to 15 hours under a temperature condition of about 40 to 90 캜 (preferably 50 to 80 캜) . For reaction control, a monomer or a thermal polymerization initiator may be added continuously or intermittently during the polymerization. The monomer or thermal initiator may be added to an organic solvent.

As the polymerization initiator, a thermal polymerization initiator, a photopolymerization initiator, and the like are used. Examples of the photopolymerization initiator include 4- (2-hydroxyethoxy) phenyl (2-hydroxy-2-propyl) ketone and the like. As the thermal polymerization initiator, for example, 2,2'-azobisisobutyronitrile, 2,2'-azobis (2-methylbutyronitrile), 1,1'-azobis (cyclohexane-1-carbonitrile) , 2,2'-azobis (2,4-dimethylvaleronitrile), 2,2'-azobis (2,4-dimethyl-4-methoxy valeronitrile) Azo compounds such as bis (2-methylpropionate) and 2,2'-azobis (2-hydroxymethylpropionitrile); Butyl peroxide, lauryl peroxide, t-butyl hydroperoxide, benzoyl peroxide, t-butyl peroxybenzoate, cumene hydroperoxide, diisopropyl peroxydicarbonate, dipropyl peroxydicarbonate, t- Organic peroxides such as neodecanoate, t-butyl peroxypivalate and (3,5,5-trimethylhexanoyl) peroxide; And inorganic peroxides such as potassium persulfate, ammonium persulfate, and hydrogen peroxide. A redox-type initiator using a peroxide and a reducing agent in combination may also be used.

The proportion of the polymerization initiator is about 0.001 to 5 parts by weight based on 100 parts by weight of the total amount of the monomers constituting the (meth) acrylic resin. The polymerization of the (meth) acrylic resin may be carried out by a polymerization method using an active energy ray (for example, ultraviolet rays).

Examples of the organic solvent include aromatic hydrocarbons such as toluene and xylene; Esters such as ethyl acetate and butyl acetate; Aliphatic alcohols such as propyl alcohol and isopropyl alcohol; And ketones such as acetone, methyl ethyl ketone and methyl isobutyl ketone.

[1-2] Crosslinking agent (B)

The pressure-sensitive adhesive composition comprises a crosslinking agent (B). The crosslinking agent (B) reacts with a polar functional group containing a hydroxy group in the (meth) acrylic resin (A).

The crosslinking agent (B) is an adduct (adduct) of a tolylene diisocyanate compound and / or a polyhydric alcohol compound of a tolylene diisocyanate compound (for example, glycerin, trimethylolpropane, etc.). Examples of the tolylene diisocyanate compound include monomethylbenzene diisocyanate such as 2,6-tolylene diisocyanate, 2,4-tolylene diisocyanate and 3,5-tolylene diisocyanate. In the present invention, the OH group (hydroxyl group) of the hydroxyalkyl group having another carbon chain length (n and m) introduced into the side chain of the (meth) acrylic resin (A) reacts with the crosslinking agent (B) Thereby forming a crosslinked structure favorable for reworkability. In particular, since the crosslinking agent (B) is composed of the tolylene diisocyanate compound and / or the polyhydric alcohol compound of the tolylene diisocyanate compound, a crosslinked structure having a better balance of strength and flexibility (flexibility) can be formed It can be presumed that there is, and the durability can be improved. In other words, high durability can be exhibited not only when it is applied to a glass substrate but also when it is applied (laminated) to, for example, an ITO substrate. Further, since the crosslinking agent (B) is an isocyanate-based compound, it is also advantageous in view of the crosslinking speed and the pot life of the pressure-sensitive adhesive composition.

The proportion of the crosslinking agent (B) is, for example, from 0.01 to 10 parts by weight (for example, from 0.05 to 5 parts by weight), preferably from 0.1 to 3 parts by weight (for example, from 0.1 to 2 parts by weight), based on 100 parts by weight of the (meth) By weight, more preferably 0.2 to 1 part by weight (e.g., 0.3 to 0.8 part by weight). The smaller the upper limit value, the better the improvement in followability (or peel resistance). The larger the lower limit value, the better the cohesion resistance (or foam resistance) and the lee workability are improved.

[1-3] The silane compound (C)

The pressure-sensitive adhesive composition includes the silane compound (C). By including the silane compound (C), adhesion (or adhesiveness) between the pressure-sensitive adhesive layer and the metal layer, the transparent electrode, the glass substrate and the like can be improved. The silane compound (C) may be a silane compound capable of bonding with a reactive group of the (meth) acrylic resin (A) (for example, an OH group of a hydroxyl group), and examples thereof include vinyltrimethoxysilane, vinyltriethoxysilane, (2-methoxyethoxy) silane, 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropyltriethoxysilane, 3-glycidoxypropylmethyldimethoxysilane, 3-glycidoxypropyl 3-chloropropylmethyldimethoxysilane, 3-chloropropyltrimethoxysilane, 3-methacryloyloxypropyltrimethoxy silane, 3-methacryloyloxypropyltrimethoxysilane, 3- Silane, 3-mercaptopropyltrimethoxysilane, and 1,3-bis (3'-trimethoxypropyl) urea.

The silane compound (C) may be a silicone oligomer type compound. When the silicone oligomer is represented by a combination of monomers, for example, 3-mercaptopropyl di- or trimethoxysilane-tetramethoxysilane oligomer, 3- Mercaptomethyl di or trimethoxysilane-tetraethoxysilane oligomer, 3-mercaptopropyl di or triethoxysilane-tetramethoxysilane oligomer, 3-mercaptomethyl di or triethoxysilane-tetraethoxysilane oligomer Containing mercaptoalkyl group-containing oligomers; And an oligomer obtained by substituting the mercaptoalkyl group of the mercaptoalkyl group-containing oligomer with another substituent [3-glycidoxypropyl group, (meth) acryloyloxypropyl group, vinyl group, amino group, etc.].

The silane compound (C) may preferably be a silane compound represented by the following formula (c1). When the pressure-sensitive adhesive composition contains the silane compound represented by the following formula (c1), the pressure-sensitive adhesive layer having excellent peeling resistance can be formed because the adhesiveness (or adhesiveness) can be further improved. The pressure-sensitive adhesive layer is also excellent in the workability. In particular, even when the pressure-sensitive adhesive layer is applied (or laminated) to a transparent electrode (for example, an ITO substrate or the like) under a high temperature environment, adhesion (or adhesiveness) can be maintained and high durability can be shown.

(Wherein B represents an alkanediyl group having 1 to 20 carbon atoms or a divalent alicyclic hydrocarbon group having 3 to 20 carbon atoms, and the alkanediyl group and -CH ₂ - constituting the alicyclic hydrocarbon group are -O- or -O-, good which may be substituted by CO-, R ¹ represents an alkyl group having 1 to 5 carbon atoms, R ^2, R ^3, R ^4, R ⁵ and R ⁶ is alkoxy of 1 to 5 carbon atoms or an alkyl group having 1 to 5 carbon atoms are each independently Lt; / RTI >

In the formula (c1), B is an alkanediyl group having 1 to 20 carbon atoms such as a methylene group, an ethylene group, a trimethylene group, a tetramethylene group, a hexamethylene group, a heptamethylene group and an octamethylene group; Cyclopentylene group), a cyclohexylene group (e.g., a 1,2-cyclohexylene group), a cyclooctylene group (e.g., 1, 2-cyclohexylene group) , 2-cyclooctylene group), and other divalent alicyclic hydrocarbon groups having 3 to 20 carbon atoms; Or an alkanediyl group thereof and a group in which -CH ₂ - constituting the alicyclic hydrocarbon group is substituted with -O- or -CO-. Preferable B is an alkanediyl group having 1 to 10 carbon atoms. R ¹ represents a methyl group, an ethyl group, a propyl group, an isopropyl group, a butyl group, a s- butyl group, a t- butyl group, Pen alkyl group of 1 to 5 carbon atoms such as a group, R ^2, R ^3, R ^4, R ⁵ and R ⁶ each independently represent an alkyl group having 1 to 5 carbon atoms exemplified for R ¹ above; Or an alkoxy group having 1 to 5 carbon atoms such as methoxy, ethoxy, propoxy, i-propoxy, butoxy, s-butoxy and t- Preferred R ² , R ³ , R ⁴ , R ⁵ and R ⁶ are an alkoxy group having 1 to 5 carbon atoms. These silane compounds (C) may be used alone or in combination of two or more.

Specific examples of the silane compound (c1) include (trimethoxysilyl) methane, 1,2-bis (trimethoxysilyl) ethane, 1,2-bis (triethoxysilyl) Bis (trimethoxysilyl) butane, 1,4-bis (triethoxysilyl) butane, 1,5-bis (Trimethoxysilyl) pentane, 1,5-bis (triethoxysilyl) pentane, 1,6-bis (trimethoxysilyl) Bis (trimethoxysilyl) octane, 1,8-bis (triethoxysilyl) octane, 1,8-bis Bis (tri C _1-5 alkoxysilyl) C _1-10 alkanes; Bis (dimethoxymethylsilyl) methane, 1,2-bis (dimethoxymethylsilyl) ethane, 1,2-bis (dimethoxyethylsilyl) ethane, 1,4- Bis (dimethoxymethylsilyl) hexane, 1,8-bis (dimethoxymethylsilyl) butane, 1,6-bis (dimethoxymethylsilyl) Bis (di C _1-5 alkoxy C _1-5 alkylsilyl) C _1-10 alkanes such as 1,8-bis (dimethoxyethylsilyl) octane; (Mono C _1-5 alkoxy-di C _1-5 alkylsilyl) C _1-10 alkanes such as 1,6-bis (methoxydimethylsilyl) hexane and 1,8-bis (methoxydimethylsilyl) . Of these, 1,2-bis (trimethoxysilyl) ethane, 1,3-bis (trimethoxysilyl) propane, 1,4-bis (trimethoxysilyl) butane, 1,5- Bis (tri C _1-3 alkoxysilyl) C _1-10 alkanes such as 1,6-bis (trimethoxysilyl) pentane, 1,6-bis (trimethoxysilyl) hexane and 1,8- , Particularly 1,6-bis (trimethoxysilyl) hexane and 1,8-bis (trimethoxysilyl) octane.

The proportion of the silane compound (C) is, for example, 0.01 to 10 parts by weight (for example, 0.03 to 5 parts by weight), preferably 0.05 to 3 parts by weight, more preferably 0.05 to 3 parts by weight, relative to 100 parts by weight of the (meth) Is 0.1 to 1 part by weight (for example, 0.2 to 0.5 part by weight). If it is not more than the upper limit, it is advantageous in suppressing the bleed-out of the silane compound (C) from the pressure-sensitive adhesive layer, and if it is not lower than the lower limit value, the adhesiveness (or adhesiveness) And the like.

[1-4] Antistatic Agent

The pressure-sensitive adhesive composition may further contain an antistatic agent. By including an antistatic agent, it is possible to improve the antistatic property of the pressure-sensitive adhesive (for example, to prevent problems caused by static electricity generated when a release film or a protective film is peeled off). As the antistatic agent, there can be mentioned conventional ones, and ionic antistatic agents are suitable. Examples of the cation component constituting the ionic antistatic agent include organic cations and inorganic cations. Examples of the organic cations include pyridinium cations, imidazolium cations, ammonium cations, sulfonium cations and phosphonium cations. Examples of the inorganic cations include alkali metal cations such as lithium cations, potassium cations, sodium cations and cesium cations, and alkaline earth metal cations such as magnesium cations and calcium cations. As the anion component constituting the ionic antistatic agent, any of an inorganic anion and an organic anion may be used, but an anion component containing a fluorine atom is preferable from the viewpoint of excellent antistatic performance. Examples of the anion component containing a fluorine atom include anions such as hexafluorophosphate anion (PF ₆ -), bis (trifluoromethanesulfonyl) imide anion [(CF ₃ SO ₂ ) ₂ N-], bis ((C ₆ F ₅ ) ₄ B-], and the like can be given as examples of the anion [(FSO ₂ ) ₂ N-] and tetra (pentafluorophenyl) borate anion [ These antistatic agents may be used alone or in combination of two or more. (Trifluoromethanesulfonyl) imide anion [(CF ₃ SO ₂ ) ₂ N-], bis (fluorosulfonyl) imide anion [(FSO ₂ ) ₂ N-], tetra (pentafluoro Phenyl) borate anion [(C ₆ F ₅ ) ₄ B-].

An ionic antistatic agent which is solid at room temperature is preferable from the viewpoint of excellent stability over time of the antistatic property of the pressure-sensitive adhesive composition.

The proportion of the antistatic agent may be, for example, 0.01 to 10 parts by weight, preferably 0.1 to 5 parts by weight, more preferably 1 to 3 parts by weight based on 100 parts by weight of the (meth) acrylic resin (A).

[1-5] Other components

The pressure-sensitive adhesive composition may contain additives such as a solvent, a crosslinking catalyst, an ultraviolet absorber, a weathering stabilizer, a tackifier, a plasticizer, a softener, a dye, a pigment, an inorganic filler and a light scattering fine particle. It is also useful to form a harder pressure-sensitive adhesive layer by blending an ultraviolet curing compound into the pressure-sensitive adhesive composition and curing the pressure-sensitive adhesive layer by irradiating ultraviolet rays after forming the pressure-sensitive adhesive layer. Examples of the crosslinking catalyst include amine compounds such as hexamethylenediamine, ethylenediamine, polyethyleneimine, hexamethylenetetramine, diethylenetriamine, triethylenetetramine, isophoronediamine, trimethylenediamine, polyamino resin and melamine resin .

The pressure-sensitive adhesive composition may contain an antirust agent from the viewpoint of enhancing the corrosion resistance of the metal in the pressure-sensitive adhesive layer. As the rust-preventive agent, for example, triazole-based compounds such as benzotriazole-based compounds; Thiazole-based compounds such as benzothiazole-based compounds; Imidazole compounds such as benzylimidazole-based compounds; Imidazoline-based compounds; Quinoline compounds; Pyridine-based compounds; Pyrimidine-based compounds; Indole-based compounds; Amine-based compounds; Urea compound; Sodium benzoate; Benzyl mercapto compounds; Di-sec-butylsulfide; And diphenyl sulfoxide.

[2] Construction and production method of optical film having pressure-sensitive adhesive layer and pressure-sensitive adhesive layer

The pressure-sensitive adhesive composition of the present invention can form a pressure-sensitive adhesive layer by performing surface activation treatment (e.g., plasma treatment, corona treatment, etc.). Usually, the pressure-sensitive adhesive layer is laminated on at least one surface of the optical film.

1 is a schematic sectional view showing an example of an optical film having a pressure-sensitive adhesive layer formed from the pressure-sensitive adhesive composition according to the present invention. An optical film (1) having a pressure-sensitive adhesive layer shown in Fig. 1 is an optical film in which an optical film (10) and a pressure-sensitive adhesive layer (20) are laminated on one side of the optical film. The pressure-sensitive adhesive layer 20 is usually directly laminated on the surface of the optical film 10. Further, the pressure-sensitive adhesive layer 20 may be laminated on both sides of the optical film 10.

When the pressure-sensitive adhesive layer 20 is laminated on the surface of the optical film 10, a primer layer is formed on the bonding surface of the optical film 10 and / or the bonding surface of the pressure-sensitive adhesive layer 20, (For example, a plasma treatment, a corona treatment, or the like) is preferably carried out, and it is particularly preferable to conduct the corona treatment.

In the case where the optical film 10 is a one-side protective polarizing plate as shown in Fig. 2, the pressure-sensitive adhesive layer 20 is usually laminated on the polarizing surface, that is, on the side opposite to the first resin film 3 in the polarizer 2 (Preferably directly laminated). When the optical film 10 is a double-side protective polarizer as shown in Fig. 3, the pressure-sensitive adhesive layer 20 may be laminated on the outer surface of any one of the first and second resin films 3 and 4, It may be laminated on the outer surface.

An antistatic layer may be separately provided between the optical film 10 and the pressure-sensitive adhesive layer 20. As the antistatic layer, there can be used silicon-based materials such as polysiloxane, inorganic metal-based materials such as tin-doped indium oxide and tin-doped antimony oxide, and organic high molecular materials such as polythiophene, polystyrenesulfonic acid and polyaniline.

The optical film (1) having a pressure sensitive adhesive layer may include a separate film (release film) laminated on the outer surface of the pressure sensitive adhesive layer (20). The separator film is usually peeled off when the pressure-sensitive adhesive layer 20 is used (for example, when the transparent conductive film is laminated on a glass substrate). The separator film is a film obtained by subjecting a surface of a film made of various resins such as polyethylene terephthalate, polybutylene terephthalate, polycarbonate, and polyarylate to a surface of the pressure-sensitive adhesive layer 20 on which a release treatment such as silicone treatment is performed good.

The optical film (1) having a pressure-sensitive adhesive layer is prepared by dissolving or dispersing the respective components constituting the pressure-sensitive adhesive composition in a solvent to prepare a pressure-sensitive adhesive composition containing a solvent and then applying and drying the pressure-sensitive adhesive composition on the surface of the optical film (10) (20). The optical film 1 having the pressure-sensitive adhesive layer can be obtained by forming the pressure-sensitive adhesive layer 20 on the release-treated surface of the separate film as described above and then laminating the pressure-sensitive adhesive layer 20 on the surface of the optical film 10 Transfer).

The thickness of the pressure-sensitive adhesive layer is usually from 2 to 40 占 퐉, preferably from 5 to 30 占 퐉, more preferably from 10 to 30 占 퐉 in view of the durability of the optical film having the pressure-sensitive adhesive layer and the reworkability of the optical film having the pressure- To 25 m. Below the upper limit value, the followability (or followability) of the pressure-sensitive adhesive layer with respect to the dimensional change of the optical film becomes good, and when it is more than the lower limit value,

The pressure-sensitive adhesive layer preferably exhibits a storage elastic modulus of 0.1 to 5 MPa in a temperature range of 23 to 80 캜. As a result, the durability of the optical film having the pressure-sensitive adhesive layer can be improved more effectively. Means that the storage elastic modulus is 0.1 to 5 MPa in the temperature range of 23 to 80 캜, which means that the storage elastic modulus is within the above range at any temperature within this range. Since the storage elastic modulus generally decreases with temperature rise, if the storage elastic moduli at 23 deg. C and 80 deg. C are all within the above range, it can be assumed that the storage elastic modulus within the above range is shown at the temperature within this range. The storage elastic modulus of the pressure-sensitive adhesive layer can be measured using a commercially available viscoelasticity measuring apparatus, for example, a viscoelasticity measuring apparatus "DYNAMIC ANALYZER RDA II" manufactured by REOMETRIC.

The gel fraction can be used as an index of cross-link density. The pressure-sensitive adhesive layer formed from the pressure-sensitive adhesive composition of the present invention has a predetermined gel fraction because it has a predetermined crosslink density. That is, the gel fraction of the pressure-sensitive adhesive layer is, for example, 50 to 95% by weight (such as 55 to 93% by weight), preferably 60 to 90% by weight (such as 65 to 90% % (E.g., 80 to 85% by weight). If the gel fraction is at least the lower limit, it is advantageous in terms of foam resistance (cohesive failure resistance) and reworkability of the pressure-sensitive adhesive layer, and if the gel fraction is not more than the upper limit value, In addition, the gel fraction can be measured by the method described in the embodiment section.

The pressure-sensitive adhesive layer formed from the pressure-sensitive adhesive composition of the present invention has a predetermined adhesive force. That is, the adhesive force of the pressure-sensitive adhesive layer after 24 hours under the conditions of a temperature of 23 占 폚 and a relative humidity of 50% by bonding the pressure-sensitive adhesive layer to a glass substrate is, for example, 0.5 to 25 N To 20 N), preferably 0.5 to 10 N (e.g., 1 to 10 N), and more preferably 1 to 8 N. If the adhesive strength is lower than the lower limit, the adhesiveness (or adhesiveness) is improved, which is advantageous for peeling resistance and the adhesive strength is lower than the upper limit value. Further, the adhesive force can be measured by the method described in the embodiment section.

[2-1] Optical film

The optical film 10 constituting the optical film 1 having the pressure-sensitive adhesive layer may be various optical films (films having optical characteristics) that can be incorporated into an image display apparatus such as a liquid crystal display apparatus. The optical film 10 may have a single layer structure (e.g., an optical functional film such as a polarizer, a retardation film, a brightness enhancement film, an antiglare film, an antireflection film, a diffusion film, Etc.). The optical film 10 is preferably a polarizing plate, a polarizer, a retardation film or a retardation film, and in particular, a polarizing plate or a polarizer is preferable. In the present specification, the optical film means a film that functions for image display (display screen, etc.) (for example, a film that functions for improving the visibility of an image). In the present specification, the term "polarizing plate" means that a resin film or a resin layer is laminated on at least one surface of a polarizer, and the term "retardation plate" means that a resin film or a resin layer is laminated on at least one surface of a retardation film.

[2-2] Polarizer

Figs. 2 and 3 are schematic sectional views showing examples of the layer structure of the polarizing plate. Fig. The polarizing plate 10a shown in Fig. 2 is a one-side protective polarizing plate in which a first resin film 3 is laminated (or laminated) on one side of the polarizer 2, and the polarizing plate 10b shown in Fig. 3 is a polarizing plate 2) is further laminated (or laminated) to the second resin film 4 on the other side thereof. The first and second resin films 3 and 4 can be bonded to the polarizer 2 through an adhesive layer or a pressure-sensitive adhesive layer not shown. The polarizing plates 10a and 10b may include films or layers other than the first and second resin films 3 and 4. [

The polarizer 2 is a film having a property of absorbing linearly polarized light having a vibration plane parallel to the absorption axis and transmitting linearly polarized light having a vibration plane perpendicular to the absorption axis (parallel to the transmission axis) A film in which a dichroic dye is adsorbed and oriented on an alcoholic resin film can be used. Examples of the dichroic dye include iodine and dichroic organic dyes.

The polyvinyl alcohol-based resin can be obtained by saponifying a polyvinyl acetate-based resin. Examples of the polyvinyl acetate-based resin include polyvinyl acetate, a monomer copolymerizable with vinyl acetate (such as unsaturated carboxylic acid, olefin, vinyl ether, unsaturated sulfonic acid, (meth) acrylamide having an ammonium group, etc.) as a homopolymer of vinyl acetate, And copolymers with vinyl acetate.

The saponification degree of the polyvinyl alcohol-based resin is usually 85 to 100 mol%, preferably 98 mol% or more. The polyvinyl alcohol resin may be modified or may be polyvinyl formal or polyvinyl acetal modified with aldehydes, for example. The average degree of polymerization of the polyvinyl alcohol-based resin is usually 1,000 to 10,000, preferably 1,500 to 5,000. The average degree of polymerization of the polyvinyl alcohol-based resin can be obtained according to JIS K 6726.

Usually, a film formed of a polyvinyl alcohol-based resin is used as a raw film of the polarizer 2. The polyvinyl alcohol resin can be formed by a known method. The thickness of the fabric film is usually 1 to 150 占 퐉, and preferably 10 占 퐉 or more, considering ease of drawing and the like.

The polarizer 2 is formed by, for example, a step of uniaxially stretching a raw film, a step of dyeing the film with a dichroic dye, a step of adsorbing the dichroic dye, a step of treating the film with an aqueous solution of boric acid, Dried, and finally dried. The thickness of the polarizer 2 is usually 1 to 30 占 퐉 and preferably 20 占 퐉 or less, more preferably 15 占 퐉 or less, particularly 10 占 퐉 or less, from the viewpoint of thinning of the optical film 1 having a pressure-sensitive adhesive layer.

A polarizer (2) obtained by adsorbing and orienting a dichroic dye to a polyvinyl alcohol-based resin film can be obtained by (1) using a single film of a polyvinyl alcohol-based resin film as a raw film and then subjecting the film to uniaxial stretching treatment and dichroic dye (2) a coating solution (aqueous solution or the like) containing a polyvinyl alcohol-based resin is coated on the base film and dried to obtain a base film having a polyvinyl alcohol-based resin layer, A method of uniaxially stretching for each film, dyeing the dichroic dye to the polyvinyl alcohol-based resin layer after stretching, and then peeling off the base film. As the base film, a film made of a thermoplastic resin such as a thermoplastic resin which can constitute the first and second resin films (3, 4) described later can be used. Preferably, a polyester resin such as polyethylene terephthalate, A polycarbonate resin, a cellulose resin such as triacetyl cellulose, a cyclic polyolefin resin such as a norbornene resin, and a polystyrene resin. Using the method 2), the polarizer 2 of a thin film can be easily manufactured, and the polarizer 2 having a thickness of, for example, 7 μm or less can be easily produced.

The first and second resin films 3 and 4 are each independently formed of a transparent thermoplastic resin, preferably a optically transparent thermoplastic resin such as a chain polyolefin resin (polyethylene resin, polypropylene resin, etc.), a cyclic polyolefin resin Polyolefin resins such as resins (norbornene resins and the like); Cellulose-based resins (such as cellulose ester-based resins); Polyester resins (polyethylene terephthalate, polyethylene naphthalate, polybutylene terephthalate and the like); Polycarbonate resins (for example, polycarbonates derived from bisphenols such as 2,2-bis (4-hydroxyphenyl) propane and the like); (Meth) acrylic resins; Polystyrene type resin; Polyether ether ketone resin; A polysulfone resin, a mixture thereof, a copolymer and the like. Of these, the first and second resin films 3 and 4 are preferably films composed of a cyclic polyolefin resin, a polycarbonate resin, a cellulose resin, a polyester resin and a (meth) acrylic resin, respectively , In particular, a film composed of a cellulose-based resin and a cyclic polyolefin-based resin.

Examples of the chain polyolefin-based resin include a homopolymer of a chain olefin such as a polyethylene resin and a polypropylene resin, and a copolymer composed of two or more chain olefins.

The cyclic polyolefin-based resin is a generic name of a resin containing, as a polymerization unit, a cyclic olefin represented by norbornene or tetracyclododecene (alias: dimethano-octahydronaphthalene) or a derivative thereof. Examples of the cyclic polyolefin resin include ring-opened (co) polymers of cyclic olefins and hydrogenated products thereof, addition polymers of cyclic olefins, copolymers of cyclic olefins and chain olefins such as ethylene and propylene, or aromatic compounds having vinyl groups, And a modified (co) polymer modified with a carboxylic acid or a derivative thereof. Of these, norbornene-based resins using norbornene monomers such as norbornene and polycyclic norbornene monomers as cyclic olefins are preferable.

The cellulose-based resin is preferably a cellulose ester-based resin, that is, a partial or complete esterified product of cellulose, and examples thereof include acetate, propionic acid, butyric acid ester and mixed ester thereof of cellulose. Of these, triacetylcellulose, diacetylcellulose, cellulose acetate propionate, cellulose acetate butyrate and the like are preferable.

The polyester-based resin is a resin other than the above-mentioned cellulose ester-based resin having an ester bond, and is generally composed of a polycondensation product of a polyvalent carboxylic acid or a derivative thereof and a polyhydric alcohol. Examples of the polyester resin include polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, polybutylene naphthalate, polytrimethylene terephthalate, polytrimethylene naphthalate, polycyclohexanedimethyl terephthalate, polycyclohexane dimethyl Phthalate and the like.

The polycarbonate resin is a polyester formed from carbonic acid and glycol or bisphenol. Of these, aromatic polycarbonates having a diphenylalkane in the molecular chain are preferable from the viewpoints of heat resistance, weather resistance and acid resistance. Examples of the polycarbonate include 2,2-bis (4-hydroxyphenyl) propane (aliphatic bisphenol A), 2,2-bis (4-hydroxyphenyl) butane, And polycarbonates derived from bisphenol such as cyclohexane, 1,1-bis (4-hydroxyphenyl) isobutane, and 1,1-bis (4-hydroxyphenyl) ethane.

The (meth) acrylic resin capable of constituting the first and second resin films (3, 4) may be a polymer composed mainly of a methacrylate ester-derived constituent unit (for example, containing 50 wt% or more thereof) , And a copolymer in which other copolymerizable components are copolymerized.

The (meth) acrylic resin may contain two or more constitutional units derived from methacrylic acid ester. Examples of the methacrylic acid ester include C ₁ -C ₄ alkyl esters of methacrylic acid such as methyl methacrylate, ethyl methacrylate and butyl methacrylate.

Examples of the copolymerizable component copolymerizable with the methacrylic acid ester include acrylic acid esters. Acrylic acid esters are preferably C ₁ -C ₈ alkyl esters of acrylic acid such as methyl acrylate, ethyl acrylate, butyl acrylate, 2-ethylhexyl acrylate and the like. Specific examples of other copolymerization components include unsaturated acids such as (meth) acrylic acid; Aromatic vinyl compounds such as styrene, halogenated styrene,? -Methylstyrene and vinyltoluene; (Meth) acrylonitrile; Unsaturated acid anhydrides such as maleic anhydride and citraconic anhydride; And unsaturated imides such as phenylmaleimide and cyclohexylmaleimide, and compounds other than acrylic ester having one polymerizable carbon-carbon double bond in the molecule. A compound having two or more polymerizable carbon-carbon double bonds in the molecule may be used as a copolymerization component. The copolymerizable components may be used alone or in combination of two or more.

The (meth) acrylic acid resin may have a cyclic structure in the main chain of the polymer in view of increasing the durability of the film. The ring structure is preferably a heterocyclic structure such as cyclic acid anhydride structure, cyclic imide structure, and lactone ring structure. Specific examples of the cyclic acid anhydride structure include anhydroglutaric acid structure and anhydrous succinic acid structure. Specific examples of the cyclic imide structure include a glutarimide structure and a succinimide structure. Specific examples of the lactone ring structure include A butyrolactone ring structure, a valerolactone ring structure, and the like.

The (meth) acrylic resin may contain acrylic rubber particles from the viewpoints of the film formability to the film and the impact resistance of the film. The acrylic rubber particles are particles composed of an elastomer mainly composed of an acrylate ester as an essential component and substantially composed of a single layer structure composed of only the elastomer but a multi layer structure composed of a single layer of an elastomer. Examples of the elastomer include a crosslinked elastic copolymer comprising an alkyl acrylate as a main component and another copolymerizable vinyl monomer and a crosslinkable monomer copolymerized with the alkyl acrylate. Examples of the alkyl acrylate as a main component of the elastomer include C ₁ -C ₈ alkyl esters of acrylic acid such as methyl acrylate, ethyl acrylate, butyl acrylate and 2-ethylhexyl acrylate. The number of carbon atoms in the alkyl group is preferably 4 or more.

Examples of other vinyl monomers copolymerizable with alkyl acrylate include compounds having one polymerizable carbon-carbon double bond in the molecule, and more specifically, methacrylic acid esters such as methyl methacrylate, aromatic vinyl compounds such as styrene , And vinyl cyan compounds such as (meth) acrylonitrile. Examples of the crosslinkable monomer include crosslinkable compounds having at least two polymerizable carbon-carbon double bonds in the molecule, and more specifically, polyvalent compounds such as ethylene glycol di (meth) acrylate and butanediol di (meth) (Meth) acrylate of an alcohol, alkenyl esters of (meth) acrylic acid such as allyl (meth) acrylate, and divinylbenzene.

The content of the acrylic rubber particles is preferably 5 parts by weight or more, and more preferably 10 parts by weight or more, based on 100 parts by weight of the (meth) acrylic resin. When the content of the acrylic rubber particles is too large, the surface hardness of the film is lowered, and when the film is subjected to the surface treatment, the solvent resistance to the organic solvent in the surface treatment agent may be lowered. Therefore, the content of the acrylic rubber particles is generally 80 parts by weight or less, preferably 60 parts by weight or less, based on 100 parts by weight of the (meth) acrylic resin.

The first and second resin films 3 and 4 may contain conventional additives in the technical field of the present invention. Examples of the additives include ultraviolet absorbers, infrared absorbers, organic dyes, pigments, inorganic pigments, antioxidants, antistatic agents, surfactants, lubricants, dispersants and heat stabilizers. Examples of the ultraviolet absorber include a salicylic acid ester compound, a benzophenone compound, a benzotriazole compound, a triazine compound, a cyano (meth) acrylate compound, and a nickel complex salt.

The first and second resin films 3 and 4 may each be a film that is not stretched or a film that is uniaxially or biaxially stretched. The first resin film 3 and / or the second resin film 4 may be a protective film that protects the polarizer 2 or may be a protective film having an optical function such as a retardation film described later. The first resin film 3 and the second resin film 4 may be the same or different.

The first resin film 3 and / or the second resin film 4 may be provided with a hard coat layer, an antiglare layer, an antireflection layer, a light diffusion layer, an antistatic layer, (Coating layer) such as an antifouling layer, a conductive layer, or the like may be provided. The thicknesses of the first resin film 3 and the second resin film 4 are each usually 1 to 150 占 퐉, preferably 5 to 100 占 퐉 (e.g., 5 to 60 占 퐉), more preferably 50 占 퐉 (or less For example, 1 to 40 mu m), and furthermore, 30 mu m or less (for example, 5 to 25 mu m).

Particularly, in the case of a small-sized polarizer used for a smart phone or a tablet type terminal, a thin film having a thickness of 30 탆 or less is often used as the first resin film 3 and / or the second resin film 4 because of the requirement for thinning , The polarizing plate has a weak force for suppressing the contracting force of the polarizer 2, and the durability tends to become insufficient. Even when such a polarizing plate is used as the optical film 10, the optical film 1 having the pressure-sensitive adhesive layer of the present invention has good durability.

The first and second resin films 3 and 4 can be bonded to the polarizer 2 through the adhesive layer or the pressure-sensitive adhesive layer. As an adhesive for forming the adhesive layer, an aqueous adhesive or an active energy ray-curable adhesive can be used.

As the water-based adhesive, a water-based adhesive (for example, an adhesive comprising a polyvinyl alcohol-based resin solution, an aqueous two-component type urethane emulsion adhesive, an aldehyde compound, an epoxy compound, a melamine compound, a methylol compound, an isocyanate compound, an amine compound, And the like). Among them, an aqueous adhesive composed of a polyvinyl alcohol-based resin aqueous solution can be suitably used. When an aqueous adhesive is used, it is preferable to carry out a step of bonding the polarizer 2 and the first and second resin films 3 and 4, followed by drying to remove water contained in the aqueous adhesive Do. After the drying step, a curing step may be performed for curing at a temperature of, for example, about 20 to 45 캜.

The active energy ray-curable adhesive refers to an adhesive which is cured by irradiating active energy rays such as ultraviolet rays or electron beams, and includes, for example, a curable composition containing a polymerizable compound and a photopolymerization initiator, a curable composition comprising a photoreactive resin, A curable composition containing a photoreactive crosslinking agent, and the like, preferably an ultraviolet curable adhesive.

In the case of using an active energy ray-curable adhesive, the polarizing element 2 and the first and second resin films 3 and 4 are bonded to each other and then a drying step is carried out if necessary. Then, A curing process for curing the curable adhesive is performed. The light source of the active energy ray is not particularly limited, but an ultraviolet ray having a light emission distribution at a wavelength of 400 nm or less is preferable.

As a method of joining the polarizer 2 and the first and second resin films 3 and 4, a method of performing surface activation treatment such as saponification treatment, corona treatment or plasma treatment on at least one of the bonding surfaces . When the resin film is bonded to both sides of the polarizer 2, the adhesive for bonding these resin films may be the same kind of adhesive or different kinds of adhesives.

The polarizing plates 10a and 10b may further include other films or layers. Specific examples thereof include a brightness enhancement film, an antiglare film, an antireflection film, a diffusion film, a light-condensing film, a pressure-sensitive adhesive layer other than the pressure-sensitive adhesive layer 20, a coating layer, and a protective film in addition to the retardation film to be described later. The protective film is a film used for the purpose of protecting the surface of the optical film 10 such as a polarizing plate from scratches or dirt. The optical film 1 having the pressure-sensitive adhesive layer is bonded to, for example, a metal layer or a substrate, .

The protective film is usually composed of a base film and a pressure-sensitive adhesive layer laminated on the base film. The base film may be a thermoplastic resin, for example, a polyolefin resin such as a polyethylene resin or a polypropylene resin; Polyester based resins such as polyethylene terephthalate and polyethylene naphthalate; Polycarbonate resin; (Meth) acrylic resin or the like.

[2-3]

The retardation film included in the retardation plate is an optical film exhibiting optical anisotropy as described above and can be used for the first and second resin films 3 and 4. In addition to the thermoplastic resin exemplified above, for example, a polyvinyl alcohol- Resin, polyarylate resin, polyimide resin, polyether sulfone resin, polyvinylidene fluoride / polymethyl methacrylate resin, liquid crystal polyester resin, ethylene-vinyl acetate copolymer saponite, polyvinyl chloride Based resin or the like can be a stretched film obtained by stretching the resin film to 1.01 to 6 times. Of these, a polycarbonate resin film, a cycloolefin resin film, a (meth) acrylic resin film, or a stretched film obtained by uniaxially or biaxially stretching a cellulose resin film is preferable. In this specification, a zero retardation film is also included in the retardation film (however, it may also be used as a protective film). In addition, a film called a uniaxial retardation film, a wide viewing angle retardation film, and a low elastic modulus retardation film can be applied as a retardation film.

The zero retardation film refers to a film having an in-plane retardation value (R _e ) and a thickness direction retardation value (R _th ) together of -15 to 15 nm. This retardation film is suitably used for an IPS mode liquid crystal display device. The in-plane retardation value (R _e ) and the thickness direction retardation value (R _th ) are preferably -10 to 10 nm, more preferably -5 to 5 nm together. The in-plane retardation value (R _e ) and the thickness direction retardation value (R _th ) referred to herein are values at a wavelength of 590 nm.

The in-plane retardation value (R _e ) and the thickness direction retardation value (R _th )

R _e = (n _x -n _y ) x d

_{R th = [(n x +} n y) / 2-n z] × d

. Wherein, n _x is a refractive index in a slow axis direction (x axis direction) in the film plane, n _y is a refractive index in the fast axis direction (y-axis direction perpendicular in a plane on the x-axis) in the film plane, n _z is the film Is the refractive index in the thickness direction (z-axis direction perpendicular to the film surface), and d is the thickness of the film.

As the zero retardation film, for example, a resin film made of a polyolefin resin such as a cellulose resin, a chain polyolefin resin and a cyclic polyolefin resin, a polyethylene terephthalate resin or a (meth) acrylic resin can be used. Particularly, a cellulose resin, a polyolefin resin or a (meth) acrylic resin is preferably used because it is easy to control the retardation value and is easily available.

A film exhibiting optical anisotropy by application and orientation of a liquid crystalline compound or a film exhibiting optical anisotropy by application of an inorganic layered compound can also be used as a retardation film. Such a phase difference film is referred to as a temperature compensation type retardation film, a film in which a rod-shaped liquid crystal sold under the trade name of " NH film " from JX Nitomon Seki Energy Co., Quot; WV Film ", a completely biaxially oriented film sold by Sumitomo Chemical Co., Ltd. under the trade name of " VAC Film "quot; new VAC film " and the like. The resin film laminated on at least one side of the retardation film may be, for example, the above-mentioned protective film.

[3] Optical laminate

Figs. 4 to 8 are schematic sectional views showing examples of the optical laminate including the optical film having the pressure-sensitive adhesive layer formed from the pressure-sensitive adhesive composition according to the present invention.

The optical laminate 5 shown in Fig. 4 is obtained by laminating the metal layer 30 (or the metal wiring layer 30) laminated on the substrate 40 with the optical film 1a (or the pressure-sensitive adhesive layer (A polarizing plate 1a equipped with a pressure-sensitive adhesive layer). The optical film 1a having the pressure-sensitive adhesive layer is obtained by laminating the pressure-sensitive adhesive layer 20 on the polarizer 2 side of the polarizing plate 10a.

The optical laminate 6 shown in Fig. 5 is a laminate in which the metal layer 30 laminated on the substrate 40 is laminated on the pressure-sensitive adhesive layer 4 of the optical film 1b (or the polarizer 1b having the pressure- Layered structure. The optical film 1b having the pressure-sensitive adhesive layer is an optical film in which a pressure-sensitive adhesive layer 20 is laminated on the surface of the polarizing plate 10b on the second resin film 4 side.

The optical laminate bodies 5 and 6 can be obtained by bonding the optical films 1a and 1b having a pressure sensitive adhesive layer to the metal layer 30 laminated on the substrate 40 with the pressure sensitive adhesive layer 20 interposed therebetween.

As a method of forming the metal layer 30 on the substrate 40, for example, a sputtering method and the like can be given. The substrate 40 may be a transparent substrate constituting a liquid crystal cell included in a touch input device, and preferably a glass substrate. As the material of the glass substrate, soda lime glass, low alkali glass, non-alkali glass, or the like can be used. The metal layer 30 may be formed on the entire surface of the substrate 40, or may be formed on a part of the substrate 40.

The metal layer 30 includes at least one metal element selected from the group consisting of aluminum, copper, silver, iron, tin, zinc, nickel, molybdenum, chromium, tungsten, lead and alloys containing two or more of these metals . Of these, from the viewpoint of conductivity, a layer containing at least one kind of metal element selected from aluminum, copper, silver and gold may be used. From the viewpoint of conductivity and cost, more preferably, Or more preferably a layer containing an aluminum element as a main component (50% by weight or more of the total metal components constituting the metal layer 30).

The metal layer 30 may be a transparent electrode layer such as ITO (tin-doped indium oxide), or may have a transparent electrode layer made of a metal oxide such as ITO together with the metal layer 30. Further, a metal mesh, a metal nanoparticle, or a layer in which metal nanowires are added to a binder in which a metal wiring layer with fine lines is disposed on a substrate may be used.

The method of preparing the metal layer 30 is not particularly limited and may be a metal foil or may be formed by a vacuum deposition method, a sputtering method, an ion plating method, an inkjet printing method, or a gravure printing method. Preferably, the metal layer 30 is formed by a sputtering method, , A metal layer formed by a gravure printing method, and more preferably a metal layer formed by sputtering. The thickness of the metal layer 30 is not particularly limited, but is usually 3 占 퐉 or less, preferably 1 占 퐉 or less, more preferably 0.8 占 퐉 or less, and usually 0.01 占 퐉 or more. When the metal layer 30 is a metal wiring layer (e.g., a metal mesh), the line width of the metal wiring is usually 10 占 퐉 or less, preferably 5 占 퐉 or less, more preferably 3 占 퐉 or less, to be.

The optical laminate 7 shown in Fig. 6 is an optical laminate obtained by laminating the pressure-sensitive adhesive layer 20 of the optical film 1 having the above-mentioned pressure-sensitive adhesive layer on a substrate 40. Fig.

The optical laminate 8 shown in Fig. 7 is formed by stacking a resin layer 50, which is further laminated on a surface of a metal layer 30 (on the surface opposite to the substrate 40) Is laminated on the side of the pressure-sensitive adhesive layer (20) side of the optical film (1) having the pressure-sensitive adhesive layer. As the resin forming the resin layer 50, for example, a resin constituting the above-described first or second resin film can be mentioned.

The optical laminate 9 shown in Fig. 8 has a structure in which a plurality of metal layers 30 are stacked on the substrate 40 at predetermined intervals in the longitudinal and transverse directions, and between the plurality of metal layers 30 (or gaps) And the resin layer 50 is formed (or laminated) on the surface of the metal layer 30 (on the surface opposite to the substrate 40). In the case where the shape of the optical multilayer body 8 (the metal layer 30 is patterned in a predetermined shape), the metal layer 30 is a metal wiring layer (i.e., electrode layer) of a touch input element of a touch input type liquid crystal display, .

In the optical laminate 8, the plurality of metal layers 30 may be entirely or partially in contact with the pressure-sensitive adhesive layer 20, or may not be in contact with each other. The metal layer 30 may be a continuous film containing the metal or alloy. The resin layer 50 may be omitted.

After the optical laminate is manufactured by sticking the optical film (1, 1a, 1b) having the pressure-sensitive adhesive layer and the substrate 40 (glass substrate, transparent substrate or the like) or the metal layer 30 (transparent electrode layer) An optical film having a pressure-sensitive adhesive layer is peeled off from the substrate 40 or the metal layer 30 and the optical film 1 having another pressure-sensitive adhesive layer is adhered to the substrate 40 or the metal layer 30, There is a case where work work is required. The optical film (1) having the pressure-sensitive adhesive layer formed from the pressure-sensitive adhesive composition according to the present invention is excellent in reworkability because it is hard to generate dark portions or grass residue on the surface of the glass substrate or the transparent electrode after peeling.

[4] liquid crystal display

The liquid crystal display device according to the present invention includes the optical film (1) having the pressure-sensitive adhesive layer formed from the pressure-sensitive adhesive composition according to the present invention, and more typically includes the optical laminate. Therefore, the liquid crystal display device according to the present invention has excellent durability.

The liquid crystal display device according to the present invention may be a touch input type liquid crystal display device having a touch panel function. A touch input type liquid crystal display device includes a touch input device including a liquid crystal cell and a backlight. The touch panel may be constructed in any known manner (e.g., an out-cell type, an on-cell type, an in-cell type, etc.) Type electrostatic capacity type) or the like. The optical film (1) having the pressure-sensitive adhesive layer according to the present invention may be disposed on the viewer side of the touch input element (liquid crystal cell), on the backlight side, or on both sides. The driving method of the liquid crystal cell may be any conventionally known method such as a TN method, a VA method, an IPS method, a multi-domain method, and an OCB method. In the liquid crystal display device according to the present invention, the substrate 40 included in the optical stacked body may be a substrate (typically, a glass substrate) included in the liquid crystal cell.

Example

Hereinafter, the present invention will be described in more detail with reference to examples and comparative examples, but the present invention is not limited to these examples. Hereinafter, parts and percentages indicating amounts used and contents are by weight unless otherwise specified.

Production Example 1: Production of (meth) acrylic resin (A-1) for pressure-sensitive adhesive layer>

Into a reaction vessel equipped with a cooling tube, a nitrogen inlet tube, a thermometer and a stirrer, a solution obtained by mixing a monomer of the composition shown in Table 1 (parts by weight in Table 1) with 81.8 parts of ethyl acetate was placed. After the air in the reaction vessel was replaced with nitrogen gas, the internal temperature was set to 60 占 폚. Thereafter, a solution prepared by dissolving 0.12 part of azobisisobutyronitrile in 10 parts of ethyl acetate was added. After maintaining the temperature at the same temperature for one hour, ethyl acetate was continuously added to the reaction vessel so that the concentration of the polymer was approximately 35% at an addition rate of 17.3 parts / Hr while maintaining the internal temperature at 54 to 56 ° C. (Meth) acryl-based resin (A-1) was prepared by maintaining the internal temperature at 54 to 56 ° C from the start of the addition of ethyl acetate to the elapse of 12 hours and then adding ethyl acetate to adjust the concentration of the polymer to 20% ) Of an ethyl acetate solution. The weight average molecular weight (Mw) of the resulting (meth) acrylic resin (A-1) was 139,000 and the ratio (Mw / Mn) of the weight average molecular weight (Mw) to the number average molecular weight (Mn) was 5.32.

Production Example 2-12: Production of (meth) acrylic resin (A-2 to 12) for pressure-

An ethyl acetate solution of the (meth) acrylic resin (A-2 to 12) was obtained in the same manner as in Production Example 1 except that the composition of the monomers was changed to the composition shown in Table 1 (resin concentration: 20%). The weight average molecular weights (Mw) of the obtained (meth) acrylic resins (A-2 to A12) were all in the range of 1.3 million to 1.5 million, and the Mw / Mn was in the range of 4 to 6.

In the above production examples, the weight average molecular weight (Mw) and the number average molecular weight (Mn) were measured in a GPC apparatus using four "TSKgel XL" manufactured by Tosoh Corporation as a column and "Shodex GPC KF-802 " were connected in series in a column, and tetrahydrofuran was used as the eluent, under conditions of a sample concentration of 5 mg / mL, a sample introduction amount of 100 mu L, a temperature of 40 DEG C and a flow rate of 1 mL / min By standard polystyrene conversion. The conditions for obtaining the discharge curve of the GPC were as described above.

The glass transition temperature (Tg) was measured using a differential scanning calorimeter (DSC) "EXSTAR DSC6000" manufactured by SII Co., Ltd. under a nitrogen atmosphere at a measurement temperature range of -80 to 50 ° C and a temperature increase rate of 10 ° C / Min.

Table 1 shows the composition of the monomers in each production example (the values in Table 1 are parts by weight).

The abbreviation in the column "monomer composition" in Table 1 means the following monomers.

BA: butyl acrylate (glass transition temperature of homopolymer: -54 DEG C)

MA: methyl acrylate (glass transition temperature of homopolymer: 10 DEG C)

HEA: 2-hydroxyethyl acrylate

4HBA: 4-hydroxybutyl acrylate

5HPA: 5-hydroxypentyl acrylate

PEA: Phenoxyethyl acrylate

PEA2: phenoxydiethylene glycol acrylate

BMAA: Butoxy methyl acrylamide

AA: Acrylic acid

≪ Examples 1 to 12 and Comparative Examples 1 to 9 >

(1) Preparation of pressure-sensitive adhesive composition

(Parts by weight) of the crosslinking agent (B) and the silane compound (B) were added to 100 parts of the solid content of the solution in the ethyl acetate solution (resin concentration: 20%) of the (meth) C) and the ionic compound (D) were mixed, and ethyl acetate was further added so that the solid concentration became 14% to obtain a pressure-sensitive adhesive composition. The compounding amount of each compounding ingredient shown in Table 2 is the number of the active ingredient contained therein in the case where the product used includes a solvent or the like.

Details of each compounding ingredient represented by abbreviations in Table 2 are as follows.

(Crosslinking agent)

B-1: Trimethylolpropane adduct of tolylene diisocyanate An ethyl acetate solution (solid concentration 75%) of the duct body and a trade name "Colonate L" obtained from Tosoh Corporation.

B-2: Ethyl acetate solution (solid content concentration 75%) of trimethylolpropane adduct of xylylene diisocyanate, trade name "Takenate D-110N" obtained from Mitsui Kagaku Co., Ltd.

(Silane compound)

C-2: 1,8-bis (trimethoxysilyl) hexane, C-3: methyl group / methoxy group-containing silicone oligomer, Shinetsu Kagaku Kogyo Co., X-40-9250 ", C-4: 1,3-bis (3'-trimethoxypropyl) urea,

(Ionic compound)

D-1: N-decalpyridinium bis (fluorosulfonyl) imide, D-2: Potassium bis (fluorosulfonyl) imide, D-3: Lithium bis (trifluoromethylsulfonyl) imide D-4: N-decalpyridinium tetra (pentafluorophenyl) borate.

(2) Production of pressure-sensitive adhesive layer

Each of the pressure-sensitive adhesive compositions prepared in (1) above was applied to the release-treated surface of a separator film (trade name "PLR-382051" available from LINTEC CO., LTD.) Made of a polyethylene terephthalate film subjected to release treatment by using an applicator To a thickness of 20 mu m, and dried at 100 DEG C for 1 minute to prepare a pressure-sensitive adhesive layer (pressure-sensitive adhesive sheet).

(3) Production of optical film (P-1) having pressure-sensitive adhesive layer

A polyvinyl alcohol film (trade name "Kurarabinetron VF-PE # 6000", manufactured by Kuraray Co., Ltd.) was immersed in pure water at 37 ° C, and an iodine And potassium iodide (iodine / potassium iodide / water (weight ratio) = 0.04 / 1.5 / 100) at 30 占 폚. Thereafter, it was immersed in an aqueous solution (potassium iodide / boric acid / water (weight ratio) = 12 / 3.6 / 100) containing potassium iodide and boric acid at 56.5 캜. The film was washed with pure water at 10 캜 and then dried at 85 캜 to obtain a polarizer having a thickness of about 23 탆 in which iodine was adsorbed and oriented in polyvinyl alcohol. The stretching was carried out mainly in a step of iodine dyeing and boric acid treatment, and the total stretching magnification was 5.3 times.

A transparent protective film (trade name: "KC2UA", manufactured by Konica Minolta Opt.) Comprising a triacetyl cellulose film having a thickness of 25 μm was bonded to one surface of the obtained polarizer through an adhesive comprising an aqueous solution of a polyvinyl alcohol-based resin. Next, a zero-phase difference film (trade name "ZEONOR", manufactured by Nippon Zeon Co., Ltd.) consisting of a ring-shaped polyolefin resin having a thickness of 23 μm was laminated on the surface opposite to the triacetylcellulose film in the polarizer, Aqueous solution to form a polarizing plate. Then, the surface of the zero-phase difference film opposite to the side on which the polarizer is touched was subjected to a corona discharge treatment for improving the adhesion, and then the surface (pressure-sensitive adhesive layer side) opposite to the separate film of the pressure- The laminate was cured for 7 days at a temperature of 23 캜 and a relative humidity of 65% to obtain an optical film (P-1) having a pressure-sensitive adhesive layer.

(4) Evaluation of durability of optical film having pressure-sensitive adhesive layer

The optical film (P-1) having the pressure-sensitive adhesive layer prepared in the above (3) was cut into a size of 300 mm x 220 mm such that the stretching axis direction of the polarizing plate was long, and the separate film was peeled off. Glass substrate or ITO (tin-doped indium oxide). The test piece to which the obtained glass substrate was adhered (optical film having a pressure-sensitive adhesive layer with a glass substrate adhered thereto) was pressed in an autoclave at a temperature of 50 占 폚 and a pressure of 5 kg / cm2 (490.3 kPa) for 20 minutes. As the glass substrate, "Eagle XG", trade name of alkali-free glass manufactured by Corning Inc. was used. As a glass substrate provided with ITO, an ITO layer having a thickness of 30 nm formed by ITO deposition was used in an alkali-free glass (trade name: "Eagle XG") manufactured by Corning Incorporated.

The following three types of durability tests were performed on the obtained optical laminate.

[Durability test]

· Heat resistance test (glass substrate) for 1000 hours holding at 95 ℃,

· Heat resistance test (glass with ITO) in which the sample is kept under a drying condition at a temperature of 95 ° C for 1000 hours,

Heat resistance test (glass substrate) in which the sample is held for 1000 hours under an environment of a temperature of 60 ° C and a relative humidity of 90%

An internal heat shock (HS) test (glass substrate) in which a cycle of holding for 30 minutes under a drying condition at a temperature of 85 ° C and then for 30 minutes under a drying condition of a temperature of -40 ° C is repeated 1000 times.

The optical laminate after each test was visually observed to visually observe whether or not appearance changes such as lifting, peeling, and foaming of the pressure-sensitive adhesive layer were observed, and durability was evaluated according to the following evaluation criteria. The results are shown in Table 3.

5: There is no change in appearance such as peeling, peeling, foaming and the like,

4: Almost no change in appearance such as peeling, peeling, foaming,

3: A slight change in the external appearance such as peeling, peeling, and foaming is conspicuous,

2: Appearance changes such as peeling, peeling, and foaming are conspicuous,

1: Appearance change such as peeling, peeling, foaming and the like is remarkably recognized.

(5) Evaluation of adhesion of optical film having pressure-sensitive adhesive layer

The optical film (P-1) having the pressure-sensitive adhesive layer prepared in the above (3) was cut into test pieces having a size of 25 mm x 150 mm. The separator was peeled from the test piece, and the adhesive surface was bonded to the glass substrate. The test piece to which the obtained glass substrate was adhered (optical film having a pressure-sensitive adhesive layer with a glass substrate adhered thereto) was pressed in an autoclave at a temperature of 50 占 폚 and a pressure of 5 kg / cm2 (490.3 kPa) for 20 minutes. After being stored for 24 hours in an atmosphere at a temperature of 23 DEG C and a relative humidity of 50%, the optical film was peeled from the test piece together with the pressure-sensitive adhesive layer at a rate of 300 mm / min in the direction of 180 DEG. The average peel force at the time of peeling is shown in Table 3 as the adhesive force. When the adhesive force is 10 N or less, the reworkability is excellent. When the adhesive force is 0.5 N or more, peeling is not likely to occur even when a shock is received from the end of the polarizing plate.

[Evaluation of ITO Corrosion of Optical Laminate]

The surface resistance (surface resistance value before test) of the ITO layer surface of the glass substrate provided with the ITO layer was measured with a low resistivity meter (trade name "Loresta AX" manufactured by Mitsubishi Chemical Corporation). Then, the polarizing plate on which the pressure-sensitive adhesive layer prepared in (3) was formed was cut into test pieces of 20 mm x 40 mm in size, and the pressure-sensitive adhesive layer was adhered to the ITO layer side of the glass substrate. The obtained optical laminate was stored in an oven at 60 ° C. and 90% relative humidity for 500 hours, and then peeled off between the ITO layer and the pressure-sensitive adhesive layer in an atmosphere at a temperature of 23 ° C. and a relative humidity of 50%. The surface resistance (surface resistance value after testing) of the ITO layer after peeling was measured. The rate of change in resistance before and after the test was calculated by the following formula and evaluated according to the following criteria. The smaller the rate of resistance change, the lower the ITO corrosion. The results are shown in Table 3.

(%) = [(Surface resistance after test) - (surface resistance before test)] / [surface resistance before test] x 100

≪ Evaluation Criteria of ITO Corrosion >

?: An optical laminate having a resistance change ratio of less than 50% and good ITO corrosion resistance.

X: The rate of change in resistance is 50% or more, and the ITO corrosion resistance of the optical laminate is poor.

(6) Evaluation of antistatic property of optical film having pressure-sensitive adhesive layer

After peeling the separator of the polarizing film provided with the obtained pressure-sensitive adhesive layer, the surface resistance value of the pressure-sensitive adhesive was measured by a surface intrinsic resistance measuring device ("Hiesta-up MCP-HT450" (trade name), manufactured by Mitsubishi Chemical Corporation) . An applied voltage of 250 V, and an application time of 10 seconds. When the surface resistance value is 1.0 x 10 < ¹² > [Omega] / square or less, good antistatic properties can be obtained.

[Gel fraction of pressure-sensitive adhesive sheet]

A method for evaluating the gel fraction of the pressure-sensitive adhesive sheet of the present invention will be described. The larger the gel fraction, the more crosslinking reaction proceeds in the pressure-sensitive adhesive, and the crosslinking density can be used as a reference. The gel fraction is a value measured according to the following (1) to (4).

(1) A metal mesh (weight is Wm) of an adhesive sheet of about 8 cm × about 8 cm in area and SUS 304 of about 10 cm × about 10 cm is bonded.

(2) The joint obtained in the above (1) is weighed, its weight is made to be Ws, then folded four times so as to wrap the adhesive sheet, and then weighed with a stapler and weighed to be Wb.

(3) In the above (2), the staple fixed mesh is placed in a glass container, and 60 mL of ethyl acetate is added to the glass container. The glass container is kept at room temperature for 3 days.

(4) Take out the mesh from the glass container, dry at 120 DEG C for 24 hours, weigh the weight, and calculate the gel fraction based on the following formula.

Gel fraction (% by weight) = [{Wa- (Wb-Ws) -Wm} / (Ws-Wm)

1, 1a, 1b: optical film having a pressure-sensitive adhesive layer, 2: polarizer, 3: first resin film, 4: second resin film, 5, 6, 7, 8, 9: optical laminate, 10a, 10b: polarizing plate, 20: pressure-sensitive adhesive layer, 30: metal layer, 40: substrate, 50: resin layer

Claims (12)

A pressure-sensitive adhesive composition comprising a (meth) acrylic resin (A), a crosslinking agent (B) and a silane compound (C)
The (meth) acrylic resin (A)

(Wherein n represents an integer of 1 to 4, A ¹ represents a hydrogen atom or an alkyl group, X ¹ represents a methylene group which may have a substituent, and when n is 2 or more, the substituents may be the same or different good)
(Meth) acrylate represented by the following formula (a2) and a structural unit derived from a hydroxyl group-containing

(Wherein m represents an integer of 5 or more, A ² represents a hydrogen atom or an alkyl group, X ² represents a methylene group which may have a substituent, and the above substituents may be the same or different)
(Meth) acrylate-containing structural unit represented by the general formula
Wherein the crosslinking agent (B) is an addition of a tolylene diisocyanate compound and / or a tolylene diisocyanate compound with a polyhydric alcohol compound. The resin composition according to claim 1, wherein the ratio of the structural unit derived from a hydroxyl group-containing (meth) acrylate represented by the formula (a1) to the total structural units constituting the (meth) acrylic resin is from 1.5 to 4.5 And the ratio of the structural unit derived from a hydroxyl group-containing (meth) acrylate represented by the formula (a2) is 0.25 to 1.0 part by weight. 3. The thermoplastic resin composition according to claim 1 or 2, wherein the (meth) acrylic resin comprises a structural unit derived from an alkyl acrylate (a3-1) having a glass transition temperature of the homopolymer of less than 0 占 폚, (A3-2) derived from an alkyl acrylate (a3-2) having a structural unit derived from an alkyl acrylate (a3-2). The composition according to claim 3, wherein the homopolymer has a constitutional unit derived from an alkyl acrylate (a3-1) having a glass transition temperature lower than 0 ° C and a constitutional unit derived from an alkyl acrylate (a3-2) having a glass transition temperature of the homopolymer of 0 ° C or higher (Weight ratio) of (a3-1) / (a3-2) = 20/80 to 95/5. The pressure-sensitive adhesive composition according to any one of claims 1 to 4, wherein the weight average molecular weight of the (meth) acrylic resin is 6.0 10 ^{5 to} 2.5 10 ⁶ in terms of polystyrene. The pressure-sensitive adhesive composition according to any one of claims 1 to 5, wherein the ratio of the crosslinking agent (B) is 0.01 to 10 parts by weight based on 100 parts by weight of the (meth) acrylic resin (A). 7. The positive resist composition according to any one of claims 1 to 6, wherein the silane compound (C)

(Wherein B represents an alkanediyl group having 1 to 20 carbon atoms or a divalent alicyclic hydrocarbon group having 3 to 20 carbon atoms, and the alkanediyl group and -CH ₂ - constituting the alicyclic hydrocarbon group are -O- or -O-, may be substituted by CO-, R ¹ represents an alkyl group having 1 to 5 carbon atoms, R ^2, R ^3, R ^4, R ⁵ and R ⁶ is alkoxy of 1 to 5 carbon atoms or an alkyl group having 1 to 5 carbon atoms are each independently Lt; / RTI >
≪ / RTI > A compound according to claim 7, wherein B in the formula (c1) is an alkanediyl group having 1 to 10 carbon atoms, R ¹ is an alkyl group having 1 to 5 carbon atoms, and R ² , R ³ , R ⁴ , R ⁵ and R ⁶ are Independently an alkoxy group having 1 to 5 carbon atoms. The pressure-sensitive adhesive composition according to any one of claims 1 to 8, wherein the proportion of the silane compound (C) is 0.01 to 10 parts by weight based on 100 parts by weight of the (meth) acrylic resin (A). The pressure-sensitive adhesive composition according to any one of claims 1 to 9, wherein the gel fraction of the pressure-sensitive adhesive formed from the pressure-sensitive adhesive composition is 50 to 95%. The pressure-sensitive adhesive sheet according to any one of claims 1 to 10, wherein the pressure-sensitive adhesive layer formed of the pressure-sensitive adhesive composition is bonded to a glass substrate and the pressure-sensitive adhesive force of the pressure-sensitive adhesive layer after 24 hours at a temperature of 23 캜 and a relative humidity of 50% , And 0.5 to 10 N / 25 mm at a peeling speed of 300 mm / min. The pressure-sensitive adhesive composition according to any one of claims 1 to 11, which is used for forming a pressure-sensitive adhesive layer to be laminated on an optical film.

Images