KR101853643B1 - Adhesive composition and surface-protective film - Google Patents

Abstract

The present invention provides a pressure-sensitive adhesive composition for a surface protective film and a surface protective film which are excellent in durability, reworkability, and antistatic property even for a polarizing plate having an acrylic protective film on its surface. A pressure-sensitive adhesive composition for a surface protective film of a polarizing plate having an acrylic protective film on its surface, comprising (A) a (meth) acrylic acid ester monomer having an alkyl group of C4 to C18, (B) a copolymerizable monomer containing a hydroxyl group, (D) a polyalkylene glycol mono (meth) acrylate monomer, and (E) a nitrogen-containing vinyl monomer or alkoxy group-containing alkyl (meth) acrylate monomer containing no hydroxyl group. (F) a trifunctional isocyanate compound, (G) a crosslinking catalyst, (H) a ketoene tautomer compound and (I) an antistatic agent, do.

Description

ADHESIVE COMPOSITION AND SURFACE-PROTECTIVE FILM < RTI ID = 0.0 >

The present invention relates to a pressure-sensitive adhesive composition and a surface protective film. More particularly, the present invention relates to an acrylic resin composition which has an antistatic property and is excellent in balance of adhesive force at a low speed peeling speed and a high speed peel rate, and which has a long pot life, excellent durability and reworkability, And a surface protective film for a surface protective film of a polarizing plate having a protective film on its surface.

BACKGROUND ART [0002] Conventionally, in a manufacturing process of an optical member such as a polarizing plate and a retarder, which constitute a liquid crystal display, a surface protective film for temporarily protecting the surface of an optical member is attached. Such a surface protective film is used only for the process of manufacturing the optical member, and is peeled off from the optical member at the time of mounting the optical member on the liquid crystal display. Since the surface protective film for protecting the surface of such an optical member is used only in the manufacturing process, it is sometimes called a process film in general.

As described above, the surface protective film used in the process of manufacturing the optical member is formed by forming a pressure-sensitive adhesive layer on one side of a polyethylene terephthalate (PET) resin film having optical transparency, Is peeled off from the surface of the pressure-sensitive adhesive layer.

In addition, since optical members such as a polarizing plate and a retardation plate are subjected to product inspection accompanied by optical evaluation such as display ability, color, contrast, and foreign substance incorporation of the liquid crystal display panel in a state where the surface protective film is stuck, It is required that the pressure-sensitive adhesive layer should not have bubbles or foreign matter attached thereto.

In recent years, when the surface protective film is peeled off from optical members such as a polarizing plate and a phase difference plate, peeling electrification caused by static electricity generated when the pressure sensitive adhesive layer is peeled off from the adherend affects the failure of the electric control circuit of the liquid crystal display And there is a demand for an excellent antistatic property for the pressure-sensitive adhesive layer.

When the surface protective film is attached to an optical member such as a polarizing plate or a retarder, the surface protective film may be peeled off once for various reasons, and the surface protective film may be reattached again for various reasons. (Reworkability) is required.

In addition, when the surface protective film is finally peeled off from optical members such as a polarizing plate and a retardation plate, it is required to be able to peel off quickly. It is required that the adhesive force is little changed even by the peeling speed so that it can be quickly peeled even by the so-called high-speed peeling.

As described above, in recent years, the required performance of the pressure-sensitive adhesive layer constituting the surface protective film has been improved as follows: (1) balance of adhesive force at low speed separation speed and high speed separation speed; (2) Excellent antistatic performance and (4) reworkability are required in terms of ease of use in using the surface protective film.

(1) to (4) required for the pressure-sensitive adhesive layer constituting the surface-protective film can satisfy the respective required performance, 4) It was a very difficult task to satisfy all required performance simultaneously.

For example, the following proposals are known for (1) balancing the adhesive force at a low speed peeling speed and a high speed peeling speed, and (2) preventing the occurrence of adhesive residue.

In the acrylic pressure-sensitive adhesive layer comprising a copolymer of a (meth) acrylic acid alkyl ester having an alkyl group having 7 or less carbon atoms and a carboxyl group-containing copolymerizable compound as a main component and crosslinking the same with a crosslinking agent, the pressure- And there is also a problem that the adhesiveness to the adherend increases with time. In order to avoid this, it has been known to use a copolymer of a (meth) acrylic acid alkyl ester having an alkyl group having 8 to 10 carbon atoms and a copolymerizable compound having an alcoholic hydroxyl group, and to form a pressure-sensitive adhesive layer crosslinked with a crosslinking agent Patent Document 1).

It has also been proposed that a small amount of a copolymer of a (meth) acrylic acid alkyl ester and a carboxyl group-containing copolymerizable compound is added to the same copolymer as described above, and a pressure-sensitive adhesive layer is formed by crosslinking the copolymer with a crosslinking agent. However, when they are used for protecting the surface of a plastic plate or the like having a low surface tension due to low surface tension, there arises a problem of peeling phenomenon such as lifting due to heating during processing or storage, There was also a problem that the peelability was poor.

In order to solve these problems, it is preferable that (a) 100 parts by weight of (a) a (meth) acrylic acid alkyl ester having a (meth) acrylic acid alkyl ester having an alkyl group having 8 to 10 carbon atoms as a main component, And c) 3 to 100 parts by weight of a vinyl ester of an aliphatic carboxylic acid having 1 to 5 carbon atoms is added to a copolymer of a monomer mixture containing a crosslinking agent in an equivalent amount or more with respect to the carboxyl group of the component b) (Patent Document 2).

In the pressure-sensitive adhesive composition described in Patent Document 2, peeling phenomena such as peeling during processing and storage are not generated, and the peelability of the adhesive strength is not so long, so that the peelability is excellent and long-term storage, It is possible to re-peel off with a small force, do not generate adhesive residue on the adherend at this time, and can peel off with small force even when high-speed peeling is performed.

As for the excellent antistatic performance, (3) a method of incorporating an antistatic agent into a base film as a method for imparting an antistatic property to the surface protective film is disclosed. Examples of the antistatic agent include (a) various cationic antistatic agents having cationic groups such as quaternary ammonium salts, pyridinium salts and primary to tertiary amino groups, (b) sulfonic acid bases, sulfuric acid ester bases, phosphoric acid An anionic antistatic agent having an anionic group such as an ester base or a phosphonic acid base, (c) a positive antistatic agent such as amino acid or amino sulfate ester, (d) a nonionic antioxidant such as amino alcohol, glycerin or polyethylene glycol (E) a polymer-type antistatic agent obtained by polymerizing an antistatic agent as described above (Patent Document 3).

Further, in recent years, it has been proposed to incorporate such an antistatic agent directly in the pressure-sensitive adhesive layer, either in the base film or not in the surface of the base film.

Regarding the reworkability, (4) a pressure-sensitive adhesive composition in which a curing agent of an isocyanate compound and an specific silicate oligomer are mixed in an acrylic resin in an amount of 0.0001 to 10 parts by weight based on 100 parts by weight of an acrylic resin (Patent Document 4).

Patent Document 4 discloses a method for producing a polyester resin composition which comprises an acrylic acid alkyl ester having an alkyl group of about 2 to 12 carbon atoms or a methacrylic acid alkyl ester having an alkyl group of about 4 to 12 as a main monomer component, Containing functional monomer component and a functional group-containing monomer component. The content of the monomer component containing a functional group is preferably 0.001 to 50% by weight, more preferably 0.001 to 25% by weight, still more preferably 0.01 to 25% by weight, . The pressure-sensitive adhesive composition described in Patent Document 4 is said to exhibit reworkability because it exhibits a small change in cohesive force and adhesive force over time under high temperature or high temperature and high humidity, and also exhibits an excellent adhesive force against a curved surface.

Generally, if the pressure-sensitive adhesive layer has a soft property, the pressure-sensitive adhesive residue tends to be generated, and the workability tends to decrease. That is, it is difficult to peel off when it is mistakenly bonded, and it is apt to be difficult to reattach. Therefore, it is considered that it is necessary to cross-link a monomer having a functional group such as a carboxyl group to a subject so as to make the pressure-sensitive adhesive layer have a constant hardness, in order to obtain reworkability.

Japanese Patent Application Laid-Open No. 63-225677 Japanese Laid-Open Patent Publication No. 11-256111 Japanese Laid-Open Patent Publication No. 11-070629 Japanese Unexamined Patent Publication No. 8-199130

A polarizing plate (hereinafter referred to as an acrylic polarizing plate) using an acrylic film in a polarizing plate (hereinafter referred to as a TAC polarizing plate) using a conventional TAC film (triacetylcellulose compound) as a protective film of a polarizing plate used for a liquid crystal display ). However, the surface protective film using an acrylic pressure-sensitive adhesive excellent in optical properties in the pressure-sensitive adhesive layer tends to have higher adhesive strength of the pressure-sensitive adhesive layer when used in an acrylic-based polarizing plate, as compared with the case where it is used in a TAC polarizing plate.

In the prior art, it has been demanded to balance the adhesive force at a low speed peeling speed and a high speed peeling speed, excellent antistatic performance and reworkability, and the like as performance requirements for the pressure-sensitive adhesive layer constituting the surface protective film. The required performance of the pressure sensitive adhesive layer of the surface protective film could not be satisfied.

The present invention has been made in view of the above circumstances, and it is an object of the present invention to provide a pressure-sensitive adhesive composition for a surface protective film and a surface protective film excellent in durability, reworkability and antistatic property even for a polarizing plate having an acrylic protective film on its surface.

The present invention provides a pressure-sensitive adhesive composition for a surface protective film of a polarizing plate having an acrylic protective film on its surface, comprising (A) a (C) a copolymerizable monomer containing a carboxyl group and (D) a polyalkylene glycol mono (meth) acrylic acid ester monomer, wherein (E) (F) a trifunctional isocyanate compound, and (G) a polyfunctional isocyanate compound, wherein the polyfunctional isocyanate compound is at least one compound selected from the group consisting of a polyfunctional isocyanate compound, A crosslinking catalyst, (H) a ketoene tautomer compound, (I) an ionic compound having a melting point of 25 to 50 占 폚 and / or an acryloyl Containing ionic compound, wherein the (D) polyalkylene glycol mono (meth) acrylic acid ester monomer is 5 parts by weight or more based on 100 parts by weight of the total amount of the acrylic polymer .

(A) 50 to 95 parts by weight of a (meth) acrylic acid ester monomer having an alkyl group having 4 to 18 carbon atoms, and (B) the hydroxyl group-containing (meth) acrylic ester monomer (C) from 0.05 to 1.0 part by weight of a copolymerizable monomer containing the carboxyl group, (D) from 5 to 50 parts by weight of the polyalkylene glycol mono (meth) acrylic acid ester monomer (D) , 0.1 to 20 parts by weight of a nitrogen-containing vinyl monomer or alkoxy group-containing alkyl (meth) acrylate monomer (E) containing no hydroxyl group, wherein the pressure-sensitive adhesive composition comprises 0.1 to 10 weight parts of the trifunctional isocyanate compound 0.001 to 0.5 parts by weight of the crosslinking catalyst (G) and 0.1 to 300 parts by weight of the ketoene alcohol tautomer compound (H) as the antistatic agent (I) (D) the polyalkylene glycol mono (meth) acrylic acid ester monomer constituting the polyalkylene glycol chain constitutes the polyalkylene glycol chain, and the total amount of the antistatic agent It is preferable that the average number of repeats of the alkylene oxide is 3 to 14, the diester content in the monomer is 0.3% or less, the water content is 0.1% or less and the solubility in water is 2% or less in the 20% Do.

It is preferable to contain 0.001 to 0.5 parts by weight of a polyether-modified siloxane compound having an HLB value of 7 to 14 with respect to 100 parts by weight of the total of the acrylic polymer of the copolymer.

(Meth) acrylate, 4-hydroxybutyl (meth) acrylate, 2-hydroxyethyl (meth) acrylate and 2-hydroxyethyl (Meth) acrylate, N-hydroxy (meth) acrylamide, N-hydroxymethyl (meth) acrylamide and N-hydroxyethyl .

(Meth) acrylic acid, carboxyethyl (meth) acrylate, carboxypentyl (meth) acrylate, 2- (meth) acryloyloxyethylhexahydrophthalic acid, 2- (Meth) acryloyloxyethylmaleic acid, 2- (meth) acryloyloxyethylphthalic acid, 2- (meth) acryloyloxyethylsuccinic acid, 2- Caprolactone mono (meth) acrylate, 2- (meth) acryloyloxyethyltetrahydrophthalic acid, and the like.

Wherein the polyalkylene glycol mono (meth) acrylate monomer (D) is at least one selected from the group consisting of polyalkylene glycol mono (meth) acrylate, methoxypolyalkylene glycol (meth) acrylate, ethoxypolyalkylene glycol At least one compound selected from the group consisting of

It is preferable that the gel fraction of the pressure-sensitive adhesive composition after crosslinking is 95 to 100%.

Wherein the (F) trifunctional isocyanate compound is an isocyanurate of a hexamethylene diisocyanate compound, an isocyanurate of an isophorone diisocyanate compound, an adduct of a hexamethylene diisocyanate compound, an isocyanurate of an isophorone diisocyanate compound An isocyanurate compound of a xylylene diisocyanate compound, an isocyanurate compound of a xylylene diisocyanate compound, an isocyanurate compound of a xylylene diisocyanate compound, an isocyanurate compound of a xylylene diisocyanate compound, a xylylene diisocyanate compound, At least one compound selected from the group consisting of an isocyanurate compound of an isocyanate compound, an adduct of a tolylene diisocyanate compound, an adduct of a xylylene diisocyanate compound, and an adduct of a hydrogenated xylylene diisocyanate compound .

(I) an ionic compound having an antistatic agent in an amount of 0.01 to 5.0 parts by weight based on 100 parts by weight of the copolymer and having a melting point of 25 to 50 DEG C, and / or an ionic compound containing 0.01 to 5.0% Containing compound is preferably an acryloyl group-containing ionic compound.

(H) / (G) wherein the (G) crosslinking catalyst is a crosslinking catalyst of a metal chelate compound, the (H) ketoene tautomer compound is contained in an amount of 1.0 to 30.0 parts by weight based on 100 parts by weight of the copolymer, Is preferably 70 to 1,000.

The adhesive force of the pressure-sensitive adhesive layer formed by crosslinking the pressure-sensitive adhesive composition to the polarizing plate having the acrylic protective film on its surface was 0.04 to 0.2 N / 25 mm at a low speed peeling rate of 0.3 m / min, Is preferably 2.0 N / 25 mm or less.

It is preferable that the pressure-sensitive adhesive layer formed by crosslinking the pressure-sensitive adhesive composition has a surface resistivity of 9.0 × 10 + ¹¹ Ω / □ or less and a peeling electrification voltage of ± 0 to 1.0 kV.

The present invention also provides a pressure-sensitive adhesive film comprising a pressure-sensitive adhesive layer formed by crosslinking the pressure-sensitive adhesive composition on one side or both sides of a resin film.

The present invention also provides a surface protective film comprising a pressure sensitive adhesive layer formed by crosslinking the pressure sensitive adhesive composition formed on one side of a resin film, wherein the surface protective film is covered with a ballpoint pen through the pressure sensitive adhesive layer, Wherein no adherence to the adherend of the polarizing plate contained in the surface protective film is caused.

It is preferable that the resin film has antistatic and antifouling treatment on the side opposite to the side where the pressure-sensitive adhesive layer is formed.

According to the present invention, it is possible to provide a pressure-sensitive adhesive composition for a surface protective film and a surface-protective film excellent in durability, reworkability, and antistatic property even for a polarizing plate having an acrylic protective film on its surface.

Hereinafter, the present invention will be described based on preferred embodiments.

The pressure-sensitive adhesive composition of the present invention is a pressure-sensitive adhesive composition for a surface protective film of a polarizing plate having an acrylic protective film on its surface, wherein (A) a monomer copolymerizable with (meth) acrylic acid ester monomers having C4- (C) a copolymerizable monomer containing a carboxyl group, and (D) a polyalkylene glycol mono (meth) acrylate monomer, wherein (E) a nitrogen-containing (F) a trifunctional isocyanate compound, (G) a cross-linking catalyst, and (D) an acrylic polymer of a copolymer containing at least one vinyl monomer or an alkyl (meth) acrylate monomer containing an alkoxy group. (I) an ionic compound having a melting point of 25 to 50 占 폚 and / or an acryloyl group-containing (meth) acryloyl group as an antistatic agent, Is made to contain a compound, wherein (D) a polyalkylene glycol mono (meth) pressure-sensitive adhesive composition, characterized in that at least 5 parts by weight based on the total 100 parts by weight of said acrylic polymer of acrylic acid ester monomer.

(A) 50 to 95 parts by weight of a (meth) acrylic acid ester monomer having an alkyl group having 4 to 18 carbon atoms and (B) a copolymerizable (meth) acrylate monomer containing a hydroxyl group, based on 100 parts by weight of the total of the acrylic polymer of the copolymer (C) a carboxyl group-containing copolymerizable monomer in an amount of 0.05 to 1.0 part by weight, (D) 5 to 50 parts by weight of a polyalkylene glycol mono (meth) acrylate monomer, (E) (F) 0.1 to 10 parts by weight of a trifunctional isocyanate compound, and (G) a crosslinking agent (C), wherein the pressure-sensitive adhesive composition is a polyfunctional (meth) acrylate monomer, 0.001 to 0.5 parts by weight of a catalyst, and (H) 0.1 to 300 parts by weight of a keto-enol tautomer compound, and further comprising (I) an antistatic agent contained in the pressure- (D) the polyalkylene glycol mono (meth) acrylic acid ester monomer has an average number of repeating alkylene oxides constituting the polyalkylene glycol chain of 3 to 14, It is preferable that the diester content in the monomer is 0.3% or less, the water content is 0.1% or less, and the solubility in water is 2% or less in the 20% aqueous solution state.

Examples of the (meth) acrylic acid ester monomer (A) in which the alkyl group has 4 to 18 carbon atoms include butyl (meth) acrylate, isobutyl (meth) acrylate, pentyl (meth) acrylate, hexyl (Meth) acrylate, octyl (meth) acrylate, isooctyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, nonyl (Meth) acrylate, isodecyl (meth) acrylate, undecyl (meth) acrylate, dodecyl (meth) acrylate, tridecyl (Meth) acrylate, heptadecyl (meth) acrylate, octadecyl (meth) acrylate, myristyl (meth) acrylate, isomyristyl Cetyl (meth) acrylate Sites, and the like can be mentioned stearyl (meth) acrylate, isostearyl (meth) acrylate.

(A) the total amount of at least one (meth) acrylate monomer having an alkyl group of C4 to C18 in an amount of 50 to 95 parts by weight relative to 100 parts by weight of the total of the acrylic polymer of the copolymer, More preferably 60 to 90 parts by weight, particularly preferably 70 to 90 parts by weight.

Examples of the copolymerizable monomer containing a hydroxyl group (B) include a copolymerizable monomer having a hydroxyl group such as 8-hydroxyoctyl (meth) acrylate, 6-hydroxyhexyl (meth) acrylate, 4-hydroxybutyl (meth) (Meth) acrylate such as ethyl (meth) acrylate, N-hydroxy (meth) acrylamide, N-hydroxymethyl (meth) acrylamide, N-hydroxyethyl (Meth) acrylamides containing hydroxyl groups.

(Meth) acrylate, 4-hydroxybutyl (meth) acrylate, 2-hydroxyethyl (meth) acrylate, N-hydroxy ) Acrylamide, N-hydroxymethyl (meth) acrylamide and N-hydroxyethyl (meth) acrylamide.

Is preferably contained in a proportion of 0.1 to 10 parts by weight, and more preferably in a proportion of 2 to 8 parts by weight, based on 100 parts by weight of the total of the acrylic polymer of the copolymer, with the total amount of at least one copolymerizable monomer (B) More preferably from 2 to 6 parts by weight, per 100 parts by weight of the total weight of the composition.

(Meth) acrylic acid, carboxyethyl (meth) acrylate, carboxypentyl (meth) acrylate, 2- (meth) acryloyloxyethylhexahydrophthalic acid, 2- (Meth) acryloyloxyethylmaleic acid, 2- (meth) acryloyloxyethylphthalic acid, 2- (meth) acryloyloxyethylsuccinic acid, 2- Caprolactone mono (meth) acrylate, 2- (meth) acryloyloxyethyltetrahydrophthalic acid, and the like.

(C) a copolymerizable monomer containing a carboxyl group in an amount of 0.05 to 1.0 part by weight relative to 100 parts by weight of the total amount of the acrylic polymer of the copolymer, and preferably 0.05 to 0.8 part by weight More preferably 0.05 to 0.5 parts by weight, based on the total weight of the composition.

As the (D) polyalkylene glycol mono (meth) acrylic acid ester monomer, any of the plurality of hydroxyl groups of the polyalkylene glycol may be a compound in which one hydroxyl group is esterified as a (meth) acrylic acid ester. (Meth) acrylic acid ester group becomes a polymerizable group, it can be copolymerized with the subject polymer. The other hydroxyl group may be the same as OH, or may be an alkyl ether such as methyl ether or ethyl ether, or a saturated carboxylic acid ester such as acetic acid ester.

Examples of the alkylene group of the polyalkylene glycol include an ethylene group, a propylene group, and a butylene group, but are not limited thereto. The polyalkylene glycol may be a copolymer of two or more kinds of polyalkylene glycols such as polyethylene glycol, polypropylene glycol and polybutylene glycol. Examples of the copolymer of polyalkylene glycol include polyethylene glycol-polypropylene glycol, polyethylene glycol-polybutylene glycol, polypropylene glycol-polybutylene glycol, and polyethylene glycol-polypropylene glycol-polybutylene glycol. The copolymer may be a block copolymer or a random copolymer.

The (D) polyalkylene glycol mono (meth) acrylic acid ester monomer preferably has an average number of repeating alkylene oxides constituting the polyalkylene glycol chain of 3 to 14. The "average number of repeating units of alkylene oxide" refers to the number of repeating units in the "polyalkylene glycol chain" included in the molecular structure of the polyalkylene glycol mono (meth) acrylate monomer (D) It is the average number.

(D) the polyalkylene glycol mono (meth) acrylic acid ester monomer is 5 parts by weight or more based on 100 parts by weight of the total of the acrylic polymer.

The (D) polyalkylene glycol mono (meth) acrylic acid ester monomer is preferably a monomer having a diester content of 0.3% or less, a water content of 0.1% or less and a solubility in water of 20% 2% or less.

The "diester content in the monomer" is the content (% by weight) of the polyalkylene glycol di (meth) acrylate ester contained in the (D) polyalkylene glycol mono (meth) acrylic acid ester monomer.

The "water content rate" is the content (% by weight) of water contained in the (D) polyalkylene glycol mono (meth) acrylic acid ester monomer.

The "haze value in the 20% aqueous solution state" is the haze value (%) of the aqueous solution in the state of (D) 20% by weight aqueous solution of the polyalkylene glycol mono (meth) acrylic acid ester monomer. That is, not only has the water-solubility (water solubility) of the polyalkylene glycol mono (meth) acrylic acid ester monomer (D) to 20% aqueous solution, but also the haze value (% Is less).

In the present specification, the haze value of the 20% aqueous solution is a value measured by a haze meter after the aqueous solution is injected into a quartz cell having an optical path length of 10 mm. This index was introduced to select a monomer having high hydrophilicity, which is a degree of hydrophilicity of the (D) polyalkylene glycol mono (meth) acrylic acid ester monomer and which gives a solution without cloudiness even at a high concentration.

Examples of the polyalkylene glycol mono (meth) acrylate monomer (D) include polyalkylene glycol mono (meth) acrylate, methoxypolyalkylene glycol (meth) acrylate, ethoxypolyalkylene glycol (meth) And at least one selected from the group consisting of:

More specifically, there may be mentioned polyolefin such as polyethylene glycol-mono (meth) acrylate, polypropylene glycol-mono (meth) acrylate, polybutylene glycol- mono (meth) acrylate, polyethylene glycol-polypropylene glycol- Poly (ethylene glycol) -polybutylene glycol-mono (meth) acrylate, polypropylene glycol-polybutylene glycol-mono (meth) acrylate, polyethylene glycol-polypropylene glycol- Rate; Methoxypolyethylene glycol- (meth) acrylate, methoxypolyethylene glycol- (meth) acrylate, methoxypolypropylene glycol- (meth) acrylate, methoxypolybutylene glycol- (meth) acrylate, methoxypolyethylene glycol- (Meth) acrylate, methoxy-polyethylene glycol-polybutylene glycol- (meth) acrylate, methoxypolypropylene glycol-polybutylene glycol- (meth) acrylate, methoxy-polyethylene glycol-polypropylene glycol-polybutylene Glycol - (meth) acrylate; Acrylate, ethoxypolyethylene glycol- (meth) acrylate, ethoxypolyethylene glycol- (meth) acrylate, ethoxypolypropylene glycol- (meth) acrylate, ethoxypolybutylene glycol- (Meth) acrylate, ethoxy-polyethylene glycol-polybutylene glycol- (meth) acrylate, ethoxy-polypropylene glycol-polybutylene glycol- Glycol- (meth) acrylate, and the like.

(Meth) acrylate monomer (D) is preferably contained in a proportion of 5 to 50 parts by weight, more preferably 5 to 40 parts by weight per 100 parts by weight of the total of the acrylic polymer of the copolymer By weight, more preferably 5 to 30 parts by weight, based on the total weight of the composition.

The acrylic polymer of the copolymer may contain, as optional components, at least one of (E) a nitrogen-containing vinyl monomer containing no hydroxyl group or an alkyl (meth) acrylate monomer containing an alkoxy group, Species. Examples of the nitrogen-containing vinyl monomer (E-1) in the component (E) include a vinyl monomer containing an amide bond, a vinyl monomer containing an amino group, and a vinyl monomer having a nitrogen-containing heterocyclic structure. More specifically, there may be mentioned N-vinyl-2-pyrrolidone, N-vinylpyrrolidone, methylvinylpyrrolidone, N- vinylpyridine, N-vinylpiperidone, N- vinylpyrimidine, Substituted vinyls such as N-vinylpyrroles, N-vinylpyrroles, N-vinylimidazoles, N-vinyloxazole, N-vinylmorpholine, N-vinylcaprolactam, N- A cyclic nitrogen vinyl compound having a heterocyclic structure; (Meth) acryloyl morpholine, N- (meth) acryloylpiperazine, N- (meth) acryloyl aziridine, N- (meth) acryloyl azetidine, N- (Meta) acryloyl-substituted complexes such as N- (meth) acryloylpiperidine, N- (meth) acryloyl azelane, N- A cyclic nitrogen vinyl compound having a cyclic structure; A cyclic nitrogen vinyl compound having a heterocyclic structure having a nitrogen atom such as N-cyclohexylmaleimide or N-phenylmaleimide and an ethylenically unsaturated bond in the ring; Unsubstituted or monoalkyl-substituted (meth) acrylamides such as N-methyl (meth) acrylamide, N-methyl (meth) acrylamide, N-isopropyl (meth) acrylamide and Nt-butyl (meth) acrylamide; (Meth) acrylamide, N, N-diethyl (meth) acrylamide, N, (Meth) acrylamide, N-methyl-N-methyl (meth) acrylamide, N-methyl- Substituted (meth) acrylamides; N, N-dimethylaminoethyl (meth) acrylate, N, N-dimethylaminopropyl (meth) acrylate, N, (Meth) acrylate, N, N-dimethylaminobutyl (meth) acrylate, N, N-diethylaminomethyl (Meth) acrylate, N, N-dibutylaminoethyl (meth) acrylate, N, N-dimethylaminoethyl (Meth) acrylate, t-butylaminoethyl (meth) acrylate and the like; N, N-diethylaminopropyl (meth) acrylamide, N, N-dipropylaminopropyl (meth) acrylamide, N, N-diisopropylaminopropyl (Meth) acrylamide, N-methyl-N-isopropylaminopropyl (meth) acrylamide, N-methyl- N, N-dialkyl-substituted aminopropyl (meth) acrylamides such as amides; N-vinylcarboxylic acid amides such as N-vinyl formamide, N-vinylacetamide and N-vinyl-N-methylacetamide; (Meth) acrylamide, N, N-methylenebis (meth) acrylamide, and the like can be used in combination with one or more of N-methoxymethyl (meth) acrylamide, N-ethoxyethyl (Meth) acrylamides; Unsaturated carboxylic acid nitriles such as (meth) acrylonitrile; And the like.

The nitrogen-containing vinyl monomer (E-1) is preferably a compound containing no hydroxyl group, and more preferably a compound containing no hydroxyl group and no carboxyl group. Examples of such monomers include acrylic monomers containing the above-exemplified monomers, for example, N, N-dialkyl substituted amino groups and N, N-dialkyl substituted amide groups; Vinyl-substituted lactams such as N-vinyl-2-pyrrolidone, N-vinylcaprolactam and N-vinyl-2-piperidone; N- (meth) acryloyl-substituted cyclic amines such as N- (meth) acryloylmorpholine and N- (meth) acryloylpyrrolidine are preferred.

(Meth) acrylate, 2-ethoxyethyl (meth) acrylate, 2-propoxyethyl (meth) acrylate and the like can be given as examples of the alkyl (meth) (Meth) acrylate, 2-ethoxypropyl (meth) acrylate, 2-butoxyethyl (meth) acrylate, 2- (Meth) acrylate, 2-propoxypropyl (meth) acrylate, 2-isopropoxypropyl (meth) acrylate, 2-butoxypropyl Propyl (meth) acrylate, 3-butoxypropyl (meth) acrylate, 4-methoxybutyl (meth) acrylate, Acrylate, 4-ethoxybutyl (meth) acrylate, 4-propoxybutyl (meth) acrylate, 4-isopropoxybutyl And the like methacrylate, 4-butoxy-butyl (meth) acrylate.

These alkoxy group-containing alkyl (meth) acrylate monomers have a structure in which the atom of the alkyl group in the alkyl (meth) acrylate is substituted with an alkoxy group.

(E) a nitrogen-containing vinyl monomer containing no hydroxyl group or an alkyl (meth) acrylate monomer containing an alkoxy group in an amount of 0.1 to 20 parts by weight based on 100 parts by weight of the total of the acrylic polymer of the copolymer More preferably 0.3 to 10 parts by weight, particularly preferably 0.3 to 8 parts by weight. (E-1) a nitrogen-containing vinyl monomer containing no hydroxyl group and (E-2) an alkyl (meth) acrylate monomer containing an alkoxy group may be used alone or in combination.

As the (F) trifunctional isocyanate compound, at least one kind or two or more kinds selected from a polyisocyanate compound having three isocyanate (NCO) groups in one molecule may be used. The polyisocyanate compound may be classified into an aliphatic isocyanate, an aromatic isocyanate, a non-glycidic isocyanate, and an alicyclic isocyanate.

Examples of the (F) trifunctional isocyanate compound include a bifunctional or isocyanurate modified product of a bifunctional isocyanate compound (a compound having two NCO groups in one molecule), a trivalent or more trivalent compound such as trimethylolpropane (TMP) And an adduct (polyol modified product) with a polyol (a compound having at least three OH groups in one molecule).

Examples of the trifunctional isocyanate compound include an isocyanurate compound of a hexamethylene diisocyanate compound, an isocyanurate compound of an isophorone diisocyanate compound, an adduct of a hexamethylene diisocyanate compound, an adduct of an isophorone diisocyanate compound A burette of hexamethylene diisocyanate compound, a burette of isophorone diisocyanate compound, an isocyanurate compound of tolylene diisocyanate compound, an isocyanurate compound of xylylene diisocyanate compound, a hydrogenated xylylene diisocyanate compound At least one selected from the group consisting of an isocyanurate of an isocyanate compound, an adduct of a tolylene diisocyanate compound, an adduct of a xylylene diisocyanate compound and an adduct of a hydrogenated xylylene diisocyanate compound desirable.

It is preferable that the (F) trifunctional isocyanate compound is contained in a proportion of 0.1 to 10 parts by weight based on 100 parts by weight of the total amount of the acrylic polymer of the copolymer.

(G) The crosslinking catalyst may be any substance that functions as a catalyst for the reaction (crosslinking reaction) between the copolymer and the crosslinking agent in the case where the polyisocyanate compound is used as a crosslinking agent. The crosslinking catalyst may be an amine compound such as a tertiary amine, , Organic tin compounds, organic lead compounds, organic zinc compounds and the like.

Examples of tertiary amines include trialkylamines, N, N, N ', N'-tetraalkyldiamines, N, N-dialkylaminoalcohols, triethylenediamine, morpholine derivatives and piperazine derivatives .

The metal chelate compound is a compound in which at least one dorsal ligand L is bonded to the central metal atom M. The metal chelate compound may or may not have at least one monocyclic ligand X bonded to the metal atom M. For example, when the chemical formula of a metal chelate compound having one metal atom M is represented by M (L) _m (X) _n , _m? 1, _n ? When m is 2 or more, m Ls may be the same ligand or different ligands. When n is 2 or more, n Xs may be the same ligand or different ligands.

Examples of the metal atom M include Fe, Ni, Mn, Cr, V, Ti, Ru, Zn, Al, Zr and Sn.

Examples of the polycondensate L include β-keto esters such as methyl acetoate, ethyl acetoate, octyl acetoate, oleyl acetoate, lauryl acetoacetate, and stearyl acetoate, acetyl acetone (also called 2,4-pentanedione) , 2,4-hexanedione, and benzoyl acetone. These are keto enol tautomeric compounds, and for the polydentate ligands L, enol may be a deprotonated enolate (for example, acetylacetonate).

Examples of the monocyclic ligand X include acyloxys such as a halogen atom such as a chlorine atom and a bromine atom, a pentanoyl group, a hexanoyl group, a 2-ethylhexanoyl group, an octanoyl group, a nonanoyl group, a decanoyl group, a dodecanoyl group, A methoxy group, an ethoxy group, an n-propoxy group, an isopropoxy group, and a butoxy group.

Specific examples of the metal chelate compound include tris (2,4-pentanedionate) iron (III), iron trisacetylacetonate, titanium trisacetylacetonate, ruthenium trisacetylacetonate, zinc bisacetylacetonate, aluminum tris (2,4-hexanedionate) iron (III), bis (2,4-hexanedionate) zinc, tris (2,4-hexanedionate) titanium, Tris (2,4-hexanedionate) aluminum, tetrakis (2,4-hexanedionate) zirconium, and the like.

Examples of the organic tin compound include dialkyltin oxide, dialkyltin fatty acid salt, and stannous acid tin salt.

The (G) crosslinking catalyst is preferably a metal chelate compound or an organotin compound. As the metal chelate compound, an aluminum chelate compound, a titanium chelate compound, an iron chelate compound, and a tin chelate compound are preferable. The organotin compound is preferably at least one selected from the group consisting of dioctyltin oxide and dioctyltin dilaurate.

The crosslinking catalyst (G) is preferably contained in an amount of 0.001 to 0.5 parts by weight based on 100 parts by weight of the total amount of the acrylic polymer of the copolymer.

Examples of the (H) ketoene tautomer compound include? -Keto esters such as methyl acetoacetate, ethyl acetoacetate, octyl acetoacetate, oleyl acetoacetate, lauryl acetoacetate, stearyl acetoacetate, , 4-hexanedione, and benzoyl acetone. (H) Ketoene enantiomeric compound is a pressure-sensitive adhesive composition comprising a polyisocyanate compound as a crosslinking agent. By blocking the isocyanate group of the crosslinking agent, the viscosity of the adhesive composition after the compounding of the crosslinking agent is increased, The pot life of the composition can be extended.

(H) ketone-enol tautomer compound, particularly preferably at least one compound selected from the group consisting of acetylacetone and ethyl acetoacetate.

(H) ketoene tautomer compound is preferably contained in a proportion of 0.1 to 300 parts by weight, more preferably 1.0 to 30.0 parts by weight, based on 100 parts by weight of the total amount of the acrylic polymer of the copolymer.

(H) Ketoenol tautomeric compound has an effect of inhibiting crosslinking as opposed to the (G) crosslinking catalyst, it is preferable to appropriately set the ratio of (H) ketoene tautomer compound to (G) . In order to extend the pot life of the pressure-sensitive adhesive composition and improve the storage stability, it is preferable that the weight ratio (H) / (G) of the (G) crosslinking catalyst to the (H) ketoenoyl tautomer compound is 70 to 1000.

(I-1) an ionic compound having a melting point of 25 to 50 占 폚 and / or (I-2) an acryloyl group-containing ionic compound.

(I-1) an ionic compound having a melting point of 25 to 50 占 폚 is added to the copolymer and / or (I-2) the acryloyl group-containing ionic compound is added to the copolymer Copolymerize. It is presumed that these (I) antistatic agents have a low melting point and also have a long chain alkyl group, so that the affinity with the acrylic copolymer is high.

(I) an antistatic agent contained in the pressure-sensitive adhesive composition as an antistatic agent and an antistatic agent copolymerized in the copolymer. It is preferable that (I) the antistatic agent is contained in an amount of 0.01 to 5.0 parts by weight of the total amount of the antistatic agent contained in the pressure-sensitive adhesive composition and the antistatic agent copolymerized in the copolymer, relative to 100 parts by weight of the acrylic polymer of the copolymer.

(I-1) As the ionic compound having a melting point of 25 to 50 캜, an ionic compound having a cation and an anion, wherein the cation is at least one selected from the group consisting of pyridinium cation, imidazolium cation, pyrimidinium cation, (PF ₆ ^- ), thiocyanate salt (SCN ^- ), phosphoric acid salt (SCN ^- ), and the like, Alkylbenzenesulfonate (RC ₆ H ₄ SO ₃ ^- ), perchlorate (ClO ₄ ^- ), tetrafluoroborate (BF ₄ ^- ), bis (fluorosulfonyl) imide salt (FSI), bis (Trifluoromethanesulfonyl) imide salt (TFSI), and trifluoromethanesulfonic acid salt (TF). It is preferably a solid at ordinary temperature (for example, 25 占 폚), and a melting point of 25 to 50 占 폚 can be obtained depending on the choice of the chain length of the alkyl group, the position and the number of substituent groups. The cation is preferably a quaternary nitrogen atom onium cation, a quaternary pyridinium cation or a quaternary pyridinium cation such as 1-alkyl pyridinium (the carbon atom at 2-6 may have a substituent or may be unsubstituted) , Quaternary imidazolium cation such as 3-dialkylimidazolium (the carbon atom at the 2, 4 and 5 positions may have a substituent or may be substituted), quaternary ammonium cation such as tetraalkylammonium And the like.

(I-1) It is preferable that the ionic compound having a melting point of 25 to 50 占 폚 is contained in an amount of 0.01 to 5.0 parts by weight based on 100 parts by weight of the acrylic polymer of the copolymer.

(I-2) The acryloyl group-containing ionic compound is an ionic compound having a cation and an anion, wherein the cation is a (meth) acryloyloxyalkyltrialkylammonium [R ₃ N ⁺ -C _n H _2n -OCOCQ = CH _2, stage, Q = H or CH _3, R = alkyl] such as (meth) and group-containing cation with acrylic, anion is hexafluorophosphate phosphate (PF ₆ ^-), thiocyanate (SCN ^-), an organic sulfonic acid And inorganic or organic anions such as salts (RSO ₃ ^- ), perchlorate (ClO ₄ ^- ), tetrafluoroborate (BF ₄ ^- ) and F-containing imide salts (R ^F ₂ N ^- ). F-containing already deuyeom (R ^F ₂ N ^-) roneun of R ^F, can be given as a trifluoromethanesulfonyl group, a pentafluorophenyl perfluoroalkyl ethane sulfonyl group, such as an alkane sulfonyl group or a fluoroalkyl sulfonyl group. F contained in an already deuyeom include bis (sulfonyl fluorophenyl) already deuyeom [(FSO _{2) 2} N ^-], bis (trifluoromethane sulfonyl) already deuyeom _{[(CF 3 SO 2) 2 N} - ], bis (Pentafluoroethanesulfonyl) imide salt [(C ₂ F ₅ SO ₂ ) ₂ N ^- ], and the like.

It is preferable that the (I-2) acryloyl group-containing ionic compound is copolymerized in the copolymer at a ratio of 0.01 to 5.0 parts by weight based on 100 parts by weight of the acrylic polymer.

Specific examples of the (I) antistatic agent include, but are not particularly limited to, (I-1) Specific examples of the ionic compound having a melting point of 25 to 50 캜 include 1-octylpyridinium hexafluorophosphate, Dodecylpyridinium dodecylbenzenesulfonate, 1-octylpyridinium dodecylbenzenesulfonate, 1-dodecylpyridinium thiocyanate, 1-dodecylpyridinium dodecylbenzene Sulfonic acid salts, 4-methyl-1-octylpyridinium hexafluorophosphate, and the like. Specific examples of the acryloyl group-containing ionic compound (I-2) include dimethylaminomethyl (meth) acrylate hexafluorophosphate methyl [(CH ₃ ) ₃ N ⁺ CH ₂ OCOCQ = CH ₂ PF ₆ ^-, with the proviso that, Q = H or CH _3], dimethylaminoethyl (meth) (methanesulfonyl-trifluoromethyl) acrylate bis salt imide methyl ^{_{[(CH 3) 3 N + (}} CH 2) 2 OCOCQ = CH 2 (CF ₃ SO ₂ ) ₂ N ^- , where Q = H or CH ₃ , dimethylaminomethyl methacrylate bis (fluorosulfonyl) imide methyl salt [(CH ₃ ) ₃ N ⁺ CH ₂ OCOCQ = CH _2. (FSO ₂ ) ₂ N ^- , with Q = H or CH ₃ ].

The pressure-sensitive adhesive composition according to the present invention may optionally contain a polyether-modified siloxane compound having an HLB value of 7 to 14. A polyether-modified siloxane compound is a siloxane compound having a polyether, in addition to conventional siloxane units [-SiR ¹ ₂ -O-], a polyether siloxane unit having a group ^{[-SiR 1 (R 2 O (R} 3 O) n R ⁴ ) -O-]. (Wherein R ¹ represents one or two or more kinds of alkyl groups or aryl groups, R ² and R ³ represent one or two or more kinds of alkylene groups, and R ⁴ represents one or two or more kinds of alkyl groups or acyl groups . Examples of the polyether group include polyoxyalkylene groups such as a polyoxyethylene group [(C ₂ H ₄ O) _n ] and a polyoxypropylene group [(C ₃ H ₆ O) _n ].

The polyether-modified siloxane compound is preferably a polyether-modified siloxane compound having an HLB value of 7 to 14. It is preferable that the polyether-modified siloxane compound having an HLB value of 7 to 14 is contained in an amount of 0.001 to 0.5 parts by weight based on 100 parts by weight of the total of the acrylic polymer of the copolymer. More preferably 0.1 to 0.5 parts by weight. HLB is a hydrophilic lipophilic balance (hydrophilic lipophilic ratio) defined by, for example, JIS K3211 (surfactant term).

The polyether-modified siloxane compound can be obtained, for example, by grafting an organic compound having an unsaturated bond and a polyoxyalkylene group to a polyorganosiloxane main chain having a hydrogenated silicon group by a hydrosilylation reaction. Specific examples thereof include dimethylsiloxane · methyl (polyoxyethylene) siloxane copolymer, dimethylsiloxane · methyl (polyoxyethylene) siloxane · methyl (polyoxypropylene) siloxane copolymer, dimethylsiloxane · methyl (polyoxypropylene) . The HLB value of the polyether-modified siloxane compound can be adjusted by selecting the ratio of the polyether group and the siloxane group.

By blending a polyether-modified siloxane compound having an HLB value of 7 to 14 in a pressure-sensitive adhesive composition, the pressure-sensitive adhesive can be improved in adhesive strength and rework performance. When the pressure-sensitive adhesive composition does not contain a polyether-modified siloxane compound, it becomes more inexpensive.

However, in the present invention, since a hydrophilic property is improved even when a siloxane compound such as a polyether-modified siloxane compound is not contained by adding a predetermined amount of (D) a polyalkylene glycol mono (meth) acrylic acid ester monomer to an adhesive, The excellent pressure-sensitive adhesive layer can be formed.

Further, it is also possible to use, as other components, a copolymerizable (meth) acrylic monomer containing an alkylene oxide, (meth) acrylamide monomer, dialkyl substituted acrylamide monomer, surfactant, curing accelerator, plasticizer, filler, Antioxidants, antioxidants, and other known additives may be appropriately added. They may be used alone or in combination of two or more.

(A) a (meth) acrylic ester monomer having an alkyl group of C4 to C18, (B) a copolymerizable monomer containing a hydroxyl group, (C) a carboxyl group-containing (D) a polyalkylene glycol mono (meth) acrylate monomer, and optionally a nitrogen-containing vinyl monomer or alkoxy group-containing alkyl (meth) acrylate monomer containing no (E) Can be synthesized. The polymerization method of the copolymer is not particularly limited, and suitable polymerization methods such as solution polymerization, emulsion polymerization and the like can be used. The monomer (E) as an optional component may be omitted.

When the (I-2) acryloyl group-containing ionic compound (I-2) is used as the antistatic agent, the subject copolymer used in the pressure sensitive adhesive composition of the present invention is a copolymer of (A) a (meth) (B) a copolymerizable monomer containing a hydroxyl group, (C) a copolymerizable monomer containing a carboxyl group, (D) a polyalkylene glycol mono (meth) acrylic acid ester monomer, and an optional component E ) Can be synthesized by polymerizing a nitrogen-containing vinyl monomer containing no hydroxyl group or an alkyl (meth) acrylate monomer containing an alkoxy group and (I-2) an acryloyl group-containing ionic compound. The monomer (E) as an optional component may be omitted.

The pressure-sensitive adhesive composition of the present invention is further prepared by blending (F) a trifunctional isocyanate compound, (G) a crosslinking catalyst, (H) a ketoene aliphatic tautomer compound, and further optionally an optional additive to the copolymer . Here, when the ionic compound containing (I-2) acryloyl group is polymerized in the copolymer of the subject, an ionic compound having a melting point (I-1) of 25 to 50 ° C may be further added to the copolymer, It may not be added.

In the production of the copolymer of the subject, in order to reduce the water content in the pressure-sensitive adhesive composition, it is preferable to conduct the polymerization reaction under anhydrous conditions, such as solution polymerization using an anhydrous organic solvent. Particularly, since the polyalkylene glycol mono (meth) acrylic acid ester monomer (D) is highly hydrophilic, it is preferable to use a monomer having a low water content.

In order to avoid an increase in the viscosity of the pressure-sensitive adhesive composition, each monomer used in the production of the copolymer of the subject is desirably as much as possible to reduce the amount of the multifunctional (bifunctional or higher) monomer capable of functioning as a crosslinking agent. Particularly, the polyalkylene glycol mono (meth) acrylic acid ester monomer (D) is preferably a di (ester) monomer because the corresponding diester moiety is a di (meth) acrylic acid ester of a bifunctional monomer.

The copolymer is preferably an acryl-based polymer, and an acrylic monomer such as (meth) acrylic acid ester monomer, (meth) acrylic acid or (meth) acryl amide is added in an amount of 50 to 100 parts by weight per 100 parts by weight of the acrylic polymer .

The acid value of the acrylic polymer is preferably 0.01 to 8.0. This makes it possible to improve stain resistance and improve the ability to prevent the occurrence of adhesive residue.

Here, "acid value" is one of the indicators of the content of the acid and is represented by the number of mg of potassium hydroxide necessary for neutralizing 1 g of the carboxyl group-containing polymer.

The adhesive force to the polarizing plate having the acrylic protective film on the surface of the pressure-sensitive adhesive layer formed by crosslinking the pressure-sensitive adhesive composition was 0.04 to 0.2 N / 25 mm at a low speed peeling speed of 0.3 m / min and the adhesive strength at a high speed peeling speed of 30 m / Is preferably 2.0 N / 25 mm or less. As a result, it is possible to obtain a performance in which the adhesive force does not change even by the peeling speed, and it is possible to peel quickly even by high-speed peeling. Further, even when the surface protective film is once peeled off for reattaching, an excessive force is not required and it is easy to peel off from the adherend.

It is preferable that the pressure-sensitive adhesive layer formed by crosslinking the pressure-sensitive adhesive composition has a surface resistivity of 9.0 × 10 + ¹¹ Ω / □ or less and a peeling electrification voltage of ± 0 to 1.0 kV. In the present invention, "± 0 to 1.0 kV" means 0 to -1.0 kV and 0 to +1.0 kV, that is, -1.0 to +1.0 kV. If the surface resistivity is large, the ability to escape the static electricity generated by the charging at the time of peeling is deteriorated. Therefore, by sufficiently reducing the surface resistivity, the peeling electrification voltage caused by the static electricity generated when the adhesive layer is peeled off from the adherend can be reduced, and the influence on the electric control circuit of the adherend and the like can be suppressed.

The gel fraction of the pressure-sensitive adhesive composition of the present invention after crosslinking is preferably 95 to 100%. As described above, the gel fraction is so high that the adhesive force does not become excessive at a low rate of peeling, and elution of the unpolymerized monomer or oligomer from the copolymer is reduced, and durability in the reworkability and high temperature and high humidity is improved, Can be suppressed.

The pressure-sensitive adhesive film of the present invention is formed by forming a pressure-sensitive adhesive layer formed by crosslinking the pressure-sensitive adhesive composition of the present invention on one side or both sides of a resin film. The surface protective film of the present invention is a surface protective film comprising a pressure-sensitive adhesive layer formed by crosslinking the pressure-sensitive adhesive composition of the present invention on one side of a resin film. Since the pressure-sensitive adhesive composition of the present invention has the components (A) to (I) in a well-balanced manner, the pressure-sensitive adhesive composition of the present invention has excellent antistatic properties and excellent balance of adhesive force at low- , Durability and reworkability (one in which there is no contamination of an adherend of a polarizing plate having an acrylic protective film on its surface after the surface protective film is overlaid with a ballpoint pen through a pressure-sensitive adhesive layer) is also excellent. Therefore, it can be preferably used as a surface protective film of a polarizing plate having an acrylic protective film on its surface.

As the release film (separator) for protecting the substrate film or the adhesive surface of the pressure-sensitive adhesive layer, a resin film such as a polyester film or the like can be used.

Antistatic treatment with an antifouling treatment with a silicon-based or fluorine-based releasing agent, a coating agent, fine silica particles, antistatic treatment by application or incorporation of an antistatic agent, etc. can be performed on the surface of the base film opposite to the side where the pressure-

The release film is subjected to releasing treatment by a silicone-based, fluorine-based releasing agent or the like on the side of the pressure-sensitive adhesive layer to be combined with the adhesive surface.

Example

Hereinafter, the present invention will be described in detail by way of examples.

≪ Preparation of acrylic copolymer >

[Example 1]

Nitrogen gas was introduced into a reactor equipped with a stirrer, a thermometer, a reflux condenser, and a nitrogen introduction tube to replace the air in the reactor with nitrogen gas. Then, 100 parts by weight of 2-ethylhexyl acrylate, 6.0 parts by weight of 8-hydroxyoctyl acrylate, 0.1 part by weight of acrylic acid, polypropylene glycol monoacrylate (alkylene oxide constituting polyalkylene glycol chain , 10 parts by weight of an average repeating number of n = 12, a diester content in a monomer of 0.1%, a solubility in water of 20%, a haze value in an aqueous solution of 0.8% and a water content of 0.05%), N-vinylpyrrolidone 2 And 60 parts by weight of a solvent (ethyl acetate) were added. Thereafter, 0.1 part by weight of azobisisobutyronitrile as a polymerization initiator was added dropwise over 2 hours and reacted at 65 DEG C for 6 hours to obtain an acrylic copolymer solution used in Example 1 having a weight average molecular weight of 500,000. A part of the acrylic copolymer was sampled and used as a measurement sample of the acid value described later.

[Examples 2 to 8 and Comparative Examples 1 to 4]

The same procedures as those of the acrylic copolymer solution used in Example 1 were carried out except that the monomers were changed as shown in Table 1 (A) to (E) and (I-2) Acrylic copolymer solutions used in Examples 1 to 4 were obtained.

≪ Preparation of pressure-sensitive adhesive composition and surface protective film &

[Example 1]

1.0 part by weight of 1-octylpyridinium hexafluorophosphate and 8.5 parts by weight of acetylacetone were added to the acrylic copolymer solution of Example 1 prepared as described above, followed by stirring. Coronate HX (isomer of hexamethylene diisocyanate compound 3.0 parts by weight of cyanurate and 0.1 part by weight of titanium trisacetylacetonate were added and stirred to obtain a pressure-sensitive adhesive composition of Example 1. This pressure-sensitive adhesive composition was coated on a release film made of a polyethylene terephthalate (PET) film coated with a silicone resin and dried at 90 ° C to remove the solvent to obtain a pressure-sensitive adhesive sheet having a pressure-sensitive adhesive layer thickness of 25 μm.

Thereafter, the pressure-sensitive adhesive sheet was transferred onto the surface opposite to the antistatic and antifouling treated surface of a polyethylene terephthalate (PET) film having antistatic and antifouling treatment on one side, Sensitive adhesive layer / release film (PET film coated with silicone resin) ".

[Examples 2 to 8 and Comparative Examples 1 to 4]

The surface protective films of Examples 2 to 8 and Comparative Examples 1 to 4 were prepared in the same manner as in the surface protective film of Example 1 except that the composition of the additives was changed as shown in Table 2 (F) to (J) .

In Table 1 and Table 2, the compounding ratio of each component is expressed in parentheses in the numerical value of the weight part obtained by taking the total of the group (A) as 100 parts by weight. In Table 1, among (I) antistatic agents, the ionic compound containing an acryloyl group copolymerized in the copolymer (I-2) is described in a column separate from the antistatic agent (I) added after polymerization.

Tables 3 and 4 show the compound names of the weak symbols of the respective components used in Tables 1 and 2. D-140N, D-127N, D-110N and D-120N are trade names of Nippon Polyurethane Industry Co., Ltd., to be. With respect to group (D) in Table 3, the numerical value of "n" is the average number of repeating alkylene oxides constituting the polyalkylene glycol chain. The value of "diester" is the diester content (%) in the monomer. The numerical value of "moisture" is the water content (%). The value of "haze" is the haze value (%) in the state of 20% aqueous solution. The values of "(H) / (G)" in Table 2 indicate weight ratios.

<Test Method and Evaluation>

After the surface protective films of Examples 1 to 8 and Comparative Examples 1 to 4 were aged for 7 days under the atmosphere of 23 ° C and 50% RH, the release film (PET film coated with silicone resin) was peeled off to expose the pressure- Was used as a sample for measuring the gel fraction and the surface resistivity.

The surface protective film on which the pressure-sensitive adhesive layer was exposed was adhered to the surface of the polarizing plate attached to the liquid crystal cell via the pressure-sensitive adhesive layer, allowed to stand for one day, autoclaved at 50 DEG C and 5 atm for 20 minutes, The sample was allowed to stand for 12 hours to measure adhesion, peeling electrification, reworkability and durability. The polarizing plate of the adherend is a polarizing plate having an acrylic protective film on its surface.

<Gel fraction>

After the completion of the aging, the mass of the pressure-sensitive adhesive layer separated from the sample to be measured before the application to the polarizing plate was precisely measured. The sample was immersed in toluene for 24 hours and then filtered through a wire mesh of 200 mesh. Thereafter, the filtrate was dried at 100 DEG C for 1 hour, and the mass of the residue was accurately measured. From the following equation, the gel fraction of the pressure-sensitive adhesive layer (pressure-sensitive adhesive layer after crosslinking) was calculated.

Gel fraction (%) = Insoluble part mass (g) / Mass of pressure-sensitive adhesive layer (g) × 100

<adhesiveness>

The test specimen obtained in the above manner (a 25 mm wide surface protective film adhered to the surface of a polarizing plate having an acrylic protective film on its surface) was peeled off at a low speed peeling speed (0.3 m / min) and a high speed peeling Peeled at a speed of 30 m / min, and the peel strength measured was determined as an adhesive force (N / 25 mm).

<Surface resistivity>

After aging, a release film (PET resin film coated with a silicone resin) was peeled off before being adhered to the polarizing plate to expose the pressure-sensitive adhesive layer, and the pressure-sensitive adhesive layer was exposed using a resistivity meter HILESTA UP-HT450 (manufactured by Mitsubishi Chemical Engineering Co., Ltd.) The resistivity (? /?) Was measured.

<Peeling Voltage>

When the measured specimen obtained above was peeled 180 ° at a tensile speed of 30 m / min, the voltage (voltage) generated by the polarizing plate having the acrylic protective film on its surface charged was measured with the high-precision electrostatic sensors SK-035 and SK- , And the maximum value of the measured values was taken as the peeling electrification voltage (kV).

<Workability>

The surface protective film of the measurement specimen obtained above was overlaid with a ballpoint pen (load: 500 g, three round trips), and then the surface protective film was peeled off from the polarizing plate to observe the surface of the polarizing plate. The evaluation target standard was "◯" when no pollution was observed on the polarizer, "Δ" when the pollution was confirmed to be at least partially along the locus padded with the ballpoint pen, the contamination was confirmed along the locus of the ballpoint pen, Quot ;, and the case where the release of the pressure-sensitive adhesive was confirmed also from &quot; X &quot;.

<durability>

The test sample thus obtained was allowed to stand in an atmosphere at 60 DEG C and 90% RH for 250 hours, taken out at room temperature and left for another 12 hours, and then its adhesive strength was measured to confirm that there was no clear increase compared with the initial adhesive strength. The evaluation target standard was evaluated as &quot;? &Quot; when the adhesion after the test was 1.5 times or less than the initial adhesion, and &quot; x &quot;

Table 5 shows the evaluation results. In addition, the surface resistivity is represented by a method of "m × 10 ^{+ n} " being "mE + n" (where m is an arbitrary real number and n is a positive integer).

The surface protective films of Examples 1 to 8 had an adhesive force of 0.04 to 0.2 N / 25 mm at a low speed peeling speed of 0.3 m / min and a fast peeling speed of 30 m / min to an adherend of a polarizing plate having an acrylic protective film on its surface , The surface resistivity is 9.0 × 10 + ¹¹ Ω / □ or less, the peeling electrification voltage is ± 0 to 1.0 kV, the surface protection film is covered with a ball pen over the pressure-sensitive adhesive layer, The durability was excellent when the complex was left to stand for 250 hours under an atmosphere of 60 DEG C and 90% RH without contamination.

That is, (1) balance the adhesive force at the low speed peeling speed and high speed peeling speed, (2) prevent the occurrence of adhesive residue, (3) excellent antistatic performance and I have to.

The surface protective film of Comparative Example 1 is a surface protective film of Comparative Example 1 in which (C) a copolymerizable monomer containing a carboxyl group is excessive, (D) a polyalkylene glycol mono (meth) acrylate monomer, (G) a crosslinking catalyst, The adhesive force at the low speed peeling speed of 0.3 m / min and the high peeling speed of 30 m / min was excessively large, and the reworkability was poor.

The surface protective film of Comparative Example 2 is a surface protective film of Comparative Example 2 in which (C) the copolymerizable monomer containing a carboxyl group is low, (D) the diester content of the polyalkylene glycol mono (meth) acrylic acid ester monomer is large and the water content is high, The adhesive strength was too large at a low rate of peeling at 0.3 m / min and at a high rate of peeling of 30 m / min, the surface resistivity and peeling voltage were high, and the durability was poor.

The surface protective film of Comparative Example 3 contained no copolymerizable monomer containing (B) a hydroxyl group, (C) a copolymerizable monomer containing a carboxyl group was excessive, (D) a polyalkylene glycol mono (meth) acrylic acid ester (H) and (H) / (G) are small, the pot life is low because the diester content of the monomer is high, the moisture content is high, the solubility in water is low, It was too short and the coating could not be performed because the gelation proceeded before application.

The surface protective film of Comparative Example 4 had a large average number of repeating units of the alkylene oxide constituting the polyalkylene glycol chain of the polyalkylene glycol mono (meth) acrylic acid ester monomer (D), a large amount of diesters, a high water content, The solubility in water was low, the content thereof was excessive, the adhesive force at a low speed peeling rate of 0.3 m / min was too small, and the reworkability and durability were poor.

As described above, in the surface protective films of Comparative Examples 1 to 4, it was found that (1) the adhesive force was balanced at the low speed peeling speed and the high speed peeling speed, (2) the generation of the adhesive remnant was prevented, (3) 4) All required performance of reworkability could not be satisfied at the same time.

Claims (15)

A pressure-sensitive adhesive composition for a surface protective film of a polarizing plate having an acrylic protective film on its surface, comprising: (A) a monomer copolymerizable with a (meth) acrylic acid ester monomer having an alkyl group having from 4 to 18 carbon atoms, (B) (D) a polyalkylene glycol mono (meth) acrylate monomer, and (E) a nitrogen-containing vinyl monomer or alkoxy group-containing (meth) acrylate monomer containing no hydroxyl group, (F) a trifunctional isocyanate compound, (G) a cross-linking catalyst, (H) a keto-enol (meth) acrylate monomer, (I) an antistatic agent containing an ionic compound and / or an acryloyl group-containing ionic compound having a melting point of 25 to 50 DEG C, It is uh,
Wherein the (D) polyalkylene glycol mono (meth) acrylic acid ester monomer is 5 parts by weight or more based on 100 parts by weight of the total of the acrylic polymer,
Wherein the polyalkylene glycol mono (meth) acrylic acid ester monomer (D) has a diester content in the monomer of 0.3% or less and a water content of 0.1% or less. The method according to claim 1,
Based on the total 100 parts by weight of the acrylic polymer of the copolymer,
The acrylic polymer
(A) 50 to 95 parts by weight of a (meth) acrylic acid ester monomer having an alkyl group having 4 to 18 carbon atoms,
0.1 to 10 parts by weight of a copolymerizable monomer containing the hydroxyl group (B)
0.05 to 1.0 part by weight of the copolymerizable monomer containing the carboxyl group (C)
(D) 5 to 50 parts by weight of a polyalkylene glycol mono (meth) acrylic acid ester monomer,
(E) 0.1 to 20 parts by weight of a nitrogen-containing vinyl monomer containing no hydroxyl group or an alkyl (meth) acrylate monomer containing an alkoxy group,
The pressure-
0.1 to 10 parts by weight of the (F) trifunctional isocyanate compound,
0.001 to 0.5 parts by weight of the crosslinking catalyst (G)
0.1 to 300 parts by weight of the (keto) enol tautomer compound (H)
The antistatic agent (I) may further contain 0.01 to 5.0 parts by weight of the total amount of the antistatic agent contained in the pressure-sensitive adhesive composition and the antistatic agent copolymerized in the copolymer,
The (D) polyalkylene glycol mono (meth) acrylic acid ester monomer preferably has an average number of repeats of alkylene oxide constituting the polyalkylene glycol chain of 3 to 14 and a solubility in water of 20% Is 2% or less. 3. The method according to claim 1 or 2,
And 0.001 to 0.5 part by weight of a polyether-modified siloxane compound having an HLB value of 7 to 14, based on 100 parts by weight of the total of the acrylic polymer of the copolymer. 3. The method according to claim 1 or 2,
(Meth) acrylate, 4-hydroxybutyl (meth) acrylate, 2-hydroxyethyl (meth) acrylate and 2-hydroxyethyl (Meth) acrylate, N-hydroxy (meth) acrylamide, N-hydroxymethyl (meth) acrylamide and N-hydroxyethyl
(Meth) acrylic acid, carboxyethyl (meth) acrylate, carboxypentyl (meth) acrylate, 2- (meth) acryloyloxyethylhexahydrophthalic acid, 2- (Meth) acryloyloxyethylmaleic acid, 2- (meth) acryloyloxyethylphthalic acid, 2- (meth) acryloyloxyethylsuccinic acid, 2- Caprolactone mono (meth) acrylate, 2- (meth) acryloyloxyethyltetrahydrophthalic acid, and the like.
Wherein the polyalkylene glycol mono (meth) acrylate monomer (D) is at least one selected from the group consisting of polyalkylene glycol mono (meth) acrylate, methoxypolyalkylene glycol (meth) acrylate, ethoxypolyalkylene glycol Wherein the pressure-sensitive adhesive composition is at least one selected from the group consisting of a compound of the following formula (1). delete delete delete delete delete delete delete delete A pressure-sensitive adhesive film comprising a pressure-sensitive adhesive layer formed by crosslinking the pressure-sensitive adhesive composition of claim 1 or 2 on one side or both sides of a resin film. A surface protective film comprising a pressure sensitive adhesive layer formed by crosslinking the pressure sensitive adhesive composition of any one of claims 1 to 3 on one side of a resin film. 15. The method of claim 14,
Wherein a surface of the resin film opposite to the side on which the pressure-sensitive adhesive layer is formed is subjected to antistatic treatment and antifouling treatment.