KR20150123147A - Adhesive composition and surface protection film - Google Patents

Abstract

The present invention provides an adhesive composition with antistatic prevention properties, excellent balance of adhesive power with respect to a slow release rate and a fast release rate, a short pot life, and excellent durability and reworkability. The adhesive composition comprises: (A) at least one kind of a meth acrylate monomer having an alkyl group including 4-18 carbon atoms; (C) 0.1-10 parts by weight of bifunctional or more-functional isocyanate compound; (D) 0.001-0.5 parts by weight of a crosslinking catalyst of a metal chelate compound; (E) 0.1-200 parts by weight of a keto-enol tautomeric compound; and (F) 0.05-5 parts by weight of an ionic compound having a melting point of 25-50°C as an antistatic agent with respect to (B) 100 parts by weight of a copolymer of a monomer including a hydroxyl group as a copolymerizable monomer group. The part-by-weight ratio of (E) to (D) is 70-700.

Description

ADHESIVE COMPOSITION AND SURFACE PROTECTION 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 a pressure-sensitive adhesive composition for a surface protective film of a polarizing plate which has an antistatic property and is excellent in balance of adhesive force at a low speed peeling speed and a high speed peeling speed, To a protective film.

As the pressure-sensitive adhesive for optical use, an acrylic pressure-sensitive adhesive comprising an alkyl (meth) acrylate as a main component and a copolymer obtained by copolymerizing with an acrylic monomer having a hydroxyl group, a carboxyl group or the like as a functional group is preferably used because of its excellent transparency. In addition, various physical properties such as adhesion of the pressure-sensitive adhesive are required to be appropriately adjusted. In particular, a pressure-sensitive adhesive for a surface protective film is excellent in the balance of adhesive force at a low speed peeling speed and a high speed peeling speed suitable for bonding a surface protective film with an automatic bonding device so as to be suitable for a manufacturing process of a factory production Is required. In addition to the balance of adhesive strength, a pressure-sensitive adhesive excellent in durability, reworkability and antistatic property is required for a long pot life.

Various physical properties of the pressure-sensitive adhesive may be obtained by crosslinking reaction using an isocyanate-based crosslinking agent, an epoxy-based crosslinking agent, or the like, which reacts with a functional group such as a hydroxyl group or a carboxyl group contained in an acrylic pressure- .

BACKGROUND ART Conventionally, isocyanate-based crosslinking agents have been widely used as crosslinking agents for acrylic pressure-sensitive adhesives. Further, in the crosslinking reaction using an isocyanate crosslinking agent, a metal chelate is frequently used as a catalyst for promoting the crosslinking reaction.

Generally, dibutyltin dilaurate, which is an organic tin compound, has been used as a catalyst for the crosslinking reaction because of the excellent reaction rate of the crosslinking reaction. However, the dibutyltin compound is avoided from being used because it exhibits toxic toxicity have.

For this reason, there is a demand for a crosslinking catalyst that is a substitute for a dibutyltin compound used in combination with an isocyanate crosslinking agent, is inexpensive, and has an excellent reaction rate of the crosslinking reaction.

Among them, Patent Document 1 discloses iron chelates as metal chelates as crosslinking catalysts used in combination with isocyanate crosslinking agents, and tris (acetylacetonate) iron is particularly preferred because of its excellent catalytic activity.

However, the acrylic pressure-sensitive adhesive composition containing a crosslinking catalyst gradually undergoes a crosslinking reaction even when it is left at room temperature. For this reason, in the industrial production of the pressure-sensitive adhesive, a crosslinking catalyst and a reaction retarder are generally used together to stop the crosslinking reaction until the time when the raw material of the pressure-sensitive adhesive composition is blended and the crosslinking reaction is started.

Regarding the combination of the crosslinking catalyst and the reaction retarder, Patent Document 2 discloses a method for producing a polyurethane comprising a mixture of at least one metal acetylacetonate and acetylacetone, wherein the metal acetylacetonate and the acetylacetone Discloses the use of a reaction urethane mixture comprising a catalyst system in a weight ratio of 2: 1.

Japanese Laid-Open Patent Publication No. 2011-001440 Japanese Patent Application Laid-Open No. 2008-285681

In the pressure-sensitive adhesive composition described in Patent Document 1, the addition amount of a metal compound (a crosslinking catalyst) to a copolymer containing a hydroxyl group and a carboxyl group is described with (meth) acrylate as a constituent monomer unit. However, There is no description about it. Patent Literature 1 discloses a method of suppressing the viscosity increase rate after the crosslinking agent is blended in the pressure-sensitive adhesive composition, a method of using a reaction retarder, a method of adding a viscosity increasing inhibiting agent, a method of using a crosslinking agent blocking a functional group such as a block isocyanate Method, and the like are exemplified, but there is no specific explanation.

In addition, Patent Document 2 discloses that metal acetylacetonate and acetylacetone having excellent stability and good catalytic activity which do not cause premature curing even when a metal acetylacetonate catalyst such as iron or copper having high activity at low temperature is used, Discloses a method for producing a polyurethane using a catalyst system containing a catalyst.

However, although the weight ratio of metal acetylacetonate to acetylacetone is 2: 1 in the method described in Patent Document 2, the crosslinking reaction can not be temporarily stopped even when this compounding ratio is applied to the production process of an acrylic pressure-sensitive adhesive.

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances and has an object of providing an antistatic composition which does not use an organotin compound and which has an antistatic property and is excellent in balance of an adhesive force at a low speed release rate and a high speed release rate, A pressure-sensitive adhesive composition for a surface protective film of a polarizing plate excellent in reworkability, and a surface protective film.

In order to solve the above-mentioned problems, the present invention relates to (A) a copolymerizable monomer group of at least one (meth) acrylic acid ester monomer having an alkyl group having from 4 to 18 carbon atoms, (B) a copolymerizable monomer containing a hydroxyl group (C) 0.1 to 10 parts by weight of an isocyanate compound having two or more functional groups, (D) 0.001 to 0.5 parts by weight of a crosslinking catalyst of a metal chelate compound, (E) 0.1 to 200 parts by weight of a ketoene tautomer compound And (F) 0.05 to 5 parts by weight of an ionic compound having a melting point of 25 to 50 DEG C as an antistatic agent, wherein the weight ratio of (E) / (D) is 70 to 700.

Further, the copolymerizable monomer (B) containing a hydroxyl group is preferably selected from the group consisting of 8-hydroxyoctyl (meth) acrylate, 6-hydroxyhexyl (meth) acrylate, 4-hydroxybutyl At least one compound selected from the group consisting of N-hydroxyethyl (meth) acrylate, N-hydroxy (meth) acrylamide, N-hydroxymethyl (meth) acrylamide and N-hydroxyethyl desirable.

The bifunctional isocyanate compound (C) as the bifunctional or higher functional isocyanate compound is preferably a compound produced by reacting a diisocyanate compound with a diol compound with an acyclic aliphatic isocyanate compound. The diisocyanate compound is preferably an aliphatic diisocyanate and is preferably one selected from the group consisting of tetramethylene diisocyanate, pentamethylene diisocyanate, hexamethylene diisocyanate, trimethylhexamethylene diisocyanate, and lysine diisocyanate. Examples of the diol compound include 2-methyl-1,3-propanediol, 2,2-dimethyl-1,3-propanediol, 1,3-propanediol, 3-methyl-1,5-pentanediol, 2,2-dimethyl-1,3-propanediol monohydroxypivalate, polyethylene glycol and polypropylene glycol And the like.

Examples of the trifunctional isocyanate compound (C) as the bifunctional or higher isocyanate compound include an isocyanurate compound of a hexamethylene diisocyanate compound, an isocyanurate compound of an isophorone diisocyanate compound, a compound of a hexamethylene diisocyanate compound An isocyanurate compound of a tolylene diisocyanate compound, an isocyanate compound of an isophorone diisocyanate compound, an isocyanate compound of an isophorone diisocyanate compound, an isocyanate compound of an isophorone diisocyanate compound, An isocyanurate of a hydrogenated xylylene diisocyanate compound, an isocyanurate of a hydrogenated xylylene diisocyanate compound, an isocyanurate of a hydrogenated xylylene diisocyanate compound, an isocyanurate of a hydrogenated xylylene diisocyanate compound, an isocyanurate of a xylylene diisocyanate compound, And at least one selected from the group of water.

The crosslinking catalyst in the pressure-sensitive adhesive composition is preferably at least one selected from the group consisting of an aluminum chelate compound, a titanium chelate compound and an iron chelate compound.

The antistatic agent (F) is an ionic compound having a melting point of 25 to 50 DEG C, which is contained in an amount of 0.05 to 5.0 parts by weight based on 100 parts by weight of the copolymer, and / Is preferably an acryloyl group-containing ionic compound.

Wherein the copolymer contains at least one or more of a carboxyl group-containing monomer, a nitrogen-containing vinyl monomer not containing a hydroxyl group, and a polyalkylene glycol mono (meth) acrylate monomer as the other copolymerizable monomer group, and / A polyether siloxane compound, and other conventional antioxidants.

The pressure-sensitive adhesive layer obtained by crosslinking the pressure-sensitive adhesive composition preferably has an adhesive force of 0.05 to 0.1 N / 25 mm at a low speed peeling rate of 0.3 m / min and an adhesive force of 1.0 N / 25 mm or less at a high peeling rate of 30 m / Do.

Further, it is preferable that the surface resistivity of the pressure-sensitive adhesive layer formed by crosslinking the pressure-sensitive adhesive composition is 9.0 × 10 ⁺¹¹ Ω / □ or less, the peeling electrification voltage is ± 0~0.5㎸.

Further, the present invention provides an 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 on one side of a resin film, wherein the surface protective film is covered with a ballpoint pen through the pressure sensitive adhesive layer, Is provided.

Further, the surface protective film of the present invention can be used as a surface protective film of a polarizing plate.

It is preferable that the surface protective film of the present invention is subjected to antistatic treatment and antifouling treatment on the side of the resin film opposite to the side where the pressure-sensitive adhesive layer is formed.

INDUSTRIAL APPLICABILITY According to the present invention, it is possible to satisfy all of the performance required for a pressure-sensitive adhesive layer of a surface protective film without using an organotin compound, which can not be solved by the prior art, Can be prevented. Specifically, the amount of the antistatic agent to be added can be reduced while maintaining an excellent antistatic property, and the performance for preventing the occurrence of adhesive residue can also be improved.

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

The pressure-sensitive adhesive composition of the present invention comprises 100 parts by weight of a copolymer of (A) a copolymerizable monomer containing at least one (meth) acrylic acid ester monomer having an alkyl group of C4 to C18 and a copolymerizable monomer group (B) (C) 0.1 to 10 parts by weight of a bifunctional or higher isocyanate compound, (D) 0.001 to 0.5 parts by weight of a crosslinking catalyst of a metal chelate compound, (E) 0.1 to 200 parts by weight of a ketoene tautomer compound, (F) 0.05 to 5 parts by weight of an ionic compound having a melting point of 25 to 50 占 폚 as an antistatic agent and the weight ratio of (E) / (D) is 70 to 700.

As the other copolymerizable monomer group, the copolymer may include at least one or more of a carboxyl group-containing monomer, a nitrogen-containing vinyl monomer not containing a hydroxyl group, and a polyalkylene glycol mono (meth) acrylate monomer.

Wherein the antistatic agent (F) is an ionic compound having a melting point of 25 to 50 占 폚, wherein the antistatic agent is contained in an amount of 0.05 to 5.0 parts by weight based on 100 parts by weight of the copolymer; and / Containing ionic compound.

Further, the pressure-sensitive adhesive composition of the present invention may include other conventional antioxidants and the like of the polyether siloxane compound as an additive.

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.

It is preferable that (A) the (meth) acrylic acid ester monomer having an alkyl group of C4 to C18 is contained in an amount of 50 to 98 parts by weight relative to 100 parts by weight of the copolymer.

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.

(B) a copolymerizable monomer containing a hydroxyl group in an amount of 0.1 to 10 parts by weight based on 100 parts by weight of the copolymer.

The copolymer may contain at least one or more of a carboxyl group-containing monomer, a nitrogen-containing vinyl monomer not containing a hydroxyl group, and a polyalkylene glycol mono (meth) acrylate monomer as another copolymerizable monomer group.

Wherein the carboxyl group-containing monomer is at least one selected from the group consisting of (meth) acrylic acid, carboxyethyl (meth) acrylate, carboxypentyl (meth) acrylate, 2- (meth) acryloyloxyethylhexahydrophthalic acid, 2- (Meth) acryloyloxyethyl methacrylate, 2- (meth) acryloyloxyethyl methacrylate, 2- (meth) acryloyloxyethyl methacrylate, 2- Acrylate, and 2- (meth) acryloyloxyethyl tetrahydrophthalic acid.

When the copolymer contains a carboxyl group-containing monomer as the other copolymerizable monomer group, it is preferable that the copolymer contains 0.1 to 1.0 part by weight of a carboxyl group-containing monomer relative to 100 parts by weight of the copolymer. The copolymer may not contain the carboxyl group-containing monomer.

As the polyalkylene glycol mono (meth) acrylic acid ester monomer, any of a 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 a subject copolymer. 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.

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

Examples of the polyalkylene glycol mono (meth) acrylate monomer include polyalkylene glycol mono (meth) acrylate, methoxypolyalkylene glycol (meth) acrylate, ethoxypolyalkylene glycol (meth) And at least one selected from the above.

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.

It is preferable that the polyalkylene glycol mono (meth) acrylate monomer is contained in an amount of 0 to 50 parts by weight based on 100 parts by weight of the copolymer. The copolymer may not contain the polyalkylene glycol mono (meth) acrylate monomer.

Examples of the nitrogen-containing vinyl monomer not containing a hydroxyl group 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 complexes such as N-vinylpyrazine, N-vinylpyrrole, N-vinylimidazole, N-vinyloxazole, N-vinylmorpholine, N-vinylcaprolactam, N- A cyclic nitrogen vinyl compound having a cyclic 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.

It is preferable that the vinyl-containing vinyl monomer containing no hydroxyl group is contained in an amount of 0 to 20 parts by weight relative to 100 parts by weight of the copolymer. The copolymer may not contain a nitrogen-containing vinyl monomer containing no hydroxyl group.

As the bifunctional or higher functional isocyanate compound (C), at least one selected from polyisocyanate compounds having at least two 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. Specific examples of the polyisocyanate compound include aliphatic isocyanate compounds such as hexamethylene diisocyanate (HDI), isophorone diisocyanate (IPDI) and trimethylhexamethylene diisocyanate (TMDI), diphenylmethane diisocyanate (MDI) Aromatic isocyanate compounds such as xylylene diisocyanate (XDI), hydrogenated xylylene diisocyanate (H6XDI), dimethyldiphenylenediisocyanate (TOID), and tolylene diisocyanate (TDI).

Examples of the trifunctional or higher isocyanate compound include buret-modified or isocyanurate-modified bifunctional isocyanate compounds (compounds having two NCO groups in one molecule), trimethylolpropane (TMP), tri- or higher-valent polyols such as glycerin And an adduct (polyol modified product) with a compound having at least three OH groups in the molecule).

It is also possible to use only the (C-1) trifunctional isocyanate compound or (C-2) bifunctional isocyanate compound as the (C) bifunctional or higher isocyanate compound. It is also possible to use the (C-1) trifunctional isocyanate compound and the (C-2) bifunctional isocyanate compound in combination.

Examples of the (C-1) trifunctional isocyanate compound used in the present invention include isocyanurate compounds of hexamethylene diisocyanate compounds, isocyanurate compounds of isophorone diisocyanate compounds, and compounds of hexamethylene diisocyanate compounds At least one member selected from the group of (C-1-1) first aliphatic isocyanate compounds consisting of a duct body, an adduct of an isophorone diisocyanate compound, a burette of a hexamethylene diisocyanate compound, and a burette of an isophorone diisocyanate compound An isocyanurate of a tolylene diisocyanate compound, an isocyanurate of a xylenediisocyanate compound, an isocyanurate of a hydrogenated xylylene diisocyanate compound, an adduct of a tolylene diisocyanate compound, The adducts, number of isocyanate compounds And at least one selected from the group of (C-1-2) second aromatic isocyanate compounds, which is an adduct of an adduct of aniline isocyanate compound and an adduct of an isocyanurate isocyanate compound. (C-1-1) first aliphatic isocyanate compound group and (C-1-2) second aromatic isocyanate compound group are preferably used in combination. In the present invention, at least one kind selected from the group consisting of (C-1-1) the first aliphatic isocyanate compounds and (C-1-2) the second aromatic isocyanate compound By using at least one selected in combination, it is possible to further improve the balance of the adhesive force in the low-speed peeling area and the high-speed peeling area.

The (C-1) trifunctional isocyanate compound is at least one selected from the group consisting of the above-mentioned (C-1-1) first aliphatic isocyanate compounds, , And preferably 0.5 to 5.0 parts by weight, based on 100 parts by weight of the copolymer. The mixing ratio of at least one selected from the group consisting of (C-1-1) the first aliphatic isocyanate compound group and the second aromatic isocyanate compound group (C-1-2) is (C- 1-1) :( C-1-2) in a weight ratio of 10%: 90% to 90%: 10%.

The (C-2) bifunctional isocyanate compound used in the present invention is preferably a non-cyclic aliphatic isocyanate compound, a compound produced by reacting a diisocyanate compound with a diol compound.

For example, the diisocyanate compound may be represented by the formula " HO-Y-OH " (Y is divalent) in the formula " O = C = NXN = C = O " , A compound produced by reacting a diisocyanate compound with a diol compound includes, for example, a compound represented by the following formula (Z).

(Z)

O = C = NX- (NH-CO-OYO-CO-NH-X) _n -N = C = O

Here, n is an integer of 0 or more. When n is 0, the formula Z represents " O = C = N-X-N = C = O ". As the bifunctional aliphatic isocyanate compound, a compound wherein n is 0 in the formula (Z) (diisocyanate compound unreacted with respect to the diol compound) may be contained, but it is preferable that the compound contains n as an essential component. The bifunctional aliphatic isocyanate compound may be a mixture of a plurality of compounds in which n in the general formula (Z) is different.

The diisocyanate compound represented by the chemical formula "O = C = N-X-N = C = O" is an aliphatic diisocyanate. X is a non-cyclic, aliphatic divalent radical. The aliphatic diisocyanate is preferably one or more selected from the group consisting of tetramethylene diisocyanate, pentamethylene diisocyanate, hexamethylene diisocyanate, trimethylhexamethylene diisocyanate, and lysine diisocyanate.

The diol compound represented by the formula " HO-Y-OH " is an aliphatic diol. Y is preferably a divalent aliphatic divalent non-cyclic. Examples of the diol compound include 2-methyl-1,3-propanediol, 2,2-dimethyl-1,3-propanediol, Methyl-1,5-pentanediol, 2,2-dimethyl-1,3-propanediol monohydroxy pivalate, polyethylene glycol, and polypropylene glycol. It is preferable that it is composed of one kind or two kinds or more selected.

The weight ratio (C-1 / C-2) of the (C-1) tribasic isocyanate compound and the (C-2) bifunctional isocyanate compound is preferably 1 to 90. It is preferable that the isocyanate compound (C) having a bifunctionality or higher is 0.1 to 10 parts by weight based on 100 parts by weight of the copolymer.

When the polyisocyanate compound is used as a crosslinking agent, the crosslinking catalyst of the metal chelate compound (D) may be any substance that functions as a catalyst for the reaction (crosslinking reaction) between the copolymer and the crosslinking agent, and an amine compound such as tertiary amine , A metal chelate compound, an organotin compound, an organic lead compound, and an organic zinc compound. In the present invention, a metal chelate compound is used as a crosslinking catalyst.

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 organotin compounds include dialkyltin oxide, dialkyltin fatty acid salts, and stannous primary fatty acid salts. Conventionally, dibutyltin compounds have been widely used. However, recently, toxicity problems of organotin compounds have been pointed out. In particular, tributyltin (TBT) contained in dibutyltin compounds is also considered as an endocrine disruptor. From the viewpoint of safety, long-chain alkyltin compounds such as dioctyltin compounds are preferable. Specific organic tin compounds include dioctyltin oxide, dioctyltin dilaurate and the like. Although Sn compounds may be used as a matter of fact, in the future, it is desirable to use metal chelate compounds such as Al, Ti, Fe, etc., which are more safe than Sn, in view of the trend of using a material having higher safety desirable.

The metal chelate compound in the pressure-sensitive adhesive composition according to the present invention is preferably at least one selected from the group consisting of an aluminum chelate compound, a titanium chelate compound and an iron chelate compound.

The crosslinking catalyst of the metal chelate compound (D) is preferably contained in an amount of 0.001 to 0.5 parts by weight based on 100 parts by weight of the copolymer.

Examples of the ketone-enol tautomer compound (E) include β-keto esters such as methyl acetoate, ethyl acetoate, octyl acetoate, oleyl acetoate, lauryl acetoacetate and stearyl acetoate, acetyl acetone, , 4-hexanedione, and benzoyl acetone. In these pressure-sensitive adhesive compositions using a polyisocyanate compound as a cross-linking agent, blocking the isocyanate group of the cross-linking agent inhibits the viscosity increase and gelation, which are excessive in the pressure-sensitive adhesive composition after the cross-linking agent is blended, and prolongs the pot life of the pressure- .

It is preferable that the (E) ketoene tautomer compound is contained in an amount of 0.1 to 200 parts by weight based on 100 parts by weight of the copolymer.

(E) Keto enol tautomer compound (D) has an effect of inhibiting crosslinking as opposed to (D) a crosslinking catalyst of a metal chelate compound, and (D) It is preferable to appropriately set the ratio of the isomeric compound. (E) / (D) of the crosslinking catalyst of the (E) ketoene aliphatic isomer compound / (D) metal chelate compound is preferably high in order to prolong the pot life of the pressure-sensitive adhesive composition and improve the storage stability Do. The value of (E) / (D) is preferably in the range of 70 to 700, more preferably 70 to 300, and most preferably 80 to 300.

(F) 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 the antistatic agent (F) is contained in an amount of 0.05 to 5.0 parts by weight based on 100 parts by weight of the copolymer.

(F) The antistatic agent is preferably (F-1) an ionic compound having a melting point of 25 to 50 캜 and / or an ionic compound containing an acryloyl group (F-2).

(F-1) an ionic compound having a melting point of 25 to 50 DEG C is added to the copolymer and / or (F-2) the acryloyl group-containing ionic compound is copolymerized in the copolymer as the antistatic agent (F) do. Since the antistatic agent (F) has a low melting point and also has a long-chain alkyl group, it is presumed that the affinity with the acrylic copolymer is high.

(F-1) As the ionic compound having a melting point of 25 to 50 占 폚, an ionic compound having a cation and an anion, wherein the cation is a pyridinium cation, an imidazolium cation, a 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 Sulfonyl) imide salt (TFSI), trifluoromethanesulfonic acid salt (TF), and the like. It is preferably 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 number of substituent groups, and the like. The cation is preferably a quaternary ammonium onium cation, a quaternary pyridinium cation such as 1-alkylpyridinium (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 unsubstituted), quaternary ammonium cation such as tetraalkylammonium, etc. .

(F-1) It is preferable that the ionic compound having a melting point of 25 to 50 占 폚 is contained in an amount of 0.05 to 5 parts by weight based on 100 parts by weight of the copolymer.

(F-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 contains the already deuyeom, 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.

The ionic compound containing (F-2) acryloyl group is preferably copolymerized in the copolymer in an amount of from 0.1 to 5.0% by weight.

(F) Specific examples of the antistatic agent include, but are not particularly limited to, (F-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 quaternary ammonium salts of trifluoromethanesulfonic acid. Specific examples of the acryloyl group-containing ionic compound (F-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], (methanesulfonyl trifluoromethyl) dimethylaminoethyl (meth) acrylate, bis-imide methyl salt ^{_{[(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 ^- , where Q = H or CH ₃ ].

The pressure-sensitive adhesive composition of the present invention may include polyether siloxane compounds and other conventional antioxidants as additives.

The polyether-modified siloxane compound is a siloxane compound having a polyether, a typical siloxane unit [-SiR ¹ ₂ -O-] In addition, the siloxane units having polyether ^{[-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 15. It is preferable that the polyether-modified siloxane compound is contained in an amount of 0.01 to 1.0 part by weight based on 100 parts by weight 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) .

By blending the polyether-modified siloxane compound with the pressure-sensitive adhesive composition, the pressure-sensitive adhesive and the pressure-sensitive adhesive can be improved. When the pressure-sensitive adhesive composition does not contain a polyether-modified siloxane compound, it becomes more inexpensive.

Examples of the antioxidant include a hindered phenol-based antioxidant, a polyphenol compound, and a tocopherol-based compound. Among them, a tocopherol compound is preferable. The tocopherol-based compounds are generally vitamin E and are also natural-derived chemicals. As a result, there are few adverse effects on the human body, high handling safety, and environment friendliness. Further, since it is an oil-soluble and liquid at room temperature, it is also excellent in compatibility with a pressure-sensitive adhesive composition and in precipitation resistance. By adding the tocopherol-based compound as the antioxidant, the storage stability of the pressure-sensitive adhesive is improved, so that the pot life of the pressure-sensitive adhesive composition containing the curing agent is improved.

The tocopherol-based compound used in the present invention is preferably a compound having no ferulic hydroxyl group in the tocopherol such as ester or the like in view of its being used in combination with the pressure-sensitive adhesive composition (it is not metabolized as in the human body) Compounds are preferred. For example, tocopherol or tocotrienol may be mentioned. It is known that tocopherol and tocotrienol have a distinction such as a natural compound (d-form), a non-natural compound (1-form) and a racemic mixture (dl-form). Natural compounds (d-form) and racemates (dl-form) are preferred because they are also used as food additives and the like.

Specific tocopherol-based compounds include d-alpha-tocopherol, dl- alpha -tocopherol, dl-beta -tocopherol, dl-beta -tocopherol, d- tocotrienol, dl-a-tocotrienol, dl-a-tocotrienol, dl-a-tocotrienol, dl-a-tocotrienol, dl- - at least one selected from the group consisting of tocotrienol. Two or more kinds of tocopherol compounds may be used in combination. As a food additive, what is termed "mixed tocopherol" is a mixture containing d-α-tocopherol, d-β-tocopherol, d-γ-tocopherol and d-δ-tocopherol as the main components, Tocotrienol, d-β-tocotrienol, d-γ-tocotrienol and d-δ-tocotrienol.

When the pressure-sensitive adhesive composition of the present invention contains a tocopherol compound, it is preferable that the tocopherol compound is contained in an amount of 0.01 to 5 parts by weight based on 100 parts by weight of the copolymer.

Further, it is also possible to use other components such as a copolymerizable (meth) acrylic monomer, a (meth) acrylamide monomer, a dialkyl substituted acrylamide monomer, a surfactant, a curing catalyst, a plasticizer, a filler, , An antioxidant, and an antioxidant may be appropriately added. These may be used alone or in combination of two or more.

The subject copolymer used in the pressure-sensitive adhesive composition of the present invention is a monomer copolymerizable with at least one of (A) a (meth) acrylic acid ester monomer having an alkyl group of C4 to C18 in number, and (B) Can be synthesized by copolymerizing monomers. 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.

(F) a copolymer of a subject to be used in the pressure-sensitive adhesive composition of the present invention, (A) a (meth) acrylate having an alkyl group having a carbon number of C4 to C18, (B) a copolymerizable monomer containing a hydroxyl group and (F-2) an acryloyl group-containing ionic compound as a copolymerizable monomer group with at least one kind of acrylic acid ester monomer.

In addition, the copolymer may include at least one or more of a carboxyl group-containing monomer, a nitrogen-containing vinyl monomer not containing a hydroxyl group, and a polyalkylene glycol mono (meth) acrylic acid ester monomer as another copolymerizable monomer group.

The pressure-sensitive adhesive composition of the present invention comprises the above copolymer, (C) a bifunctional or higher isocyanate compound, (D) a crosslinking catalyst of a metal chelate compound, (E) a ketoene tautomer compound, and (F) -1) an ionic compound having a melting point of 25 to 50 캜, and further optionally, an optional additive. When (F-2) an acryloyl group-containing ionic compound is polymerized in the copolymer of the subject, (F) an antistatic agent (F-1) May be further added or not added.

The copolymer is preferably an acrylic polymer, and it is preferable that the copolymer contains 50 to 100% by weight of an acrylic monomer such as (meth) acrylate monomer, (meth) acrylic acid or (meth) acrylamide.

The acid value of the copolymer 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 indices indicating the content of the acid, and represents 1 g of the polymer containing a carboxyl group, in mg of potassium hydroxide necessary for neutralization.

It is preferable that the pressure-sensitive adhesive layer formed by crosslinking the pressure-sensitive adhesive composition has an adhesive force of 0.05 to 0.1 N / 25 mm at a low speed peeling speed of 0.3 m / min and an adhesive force of 1.0 N / 25 mm or less at a high speed peeling speed of 30 m / . 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. In addition, in order to reattach it, an excessive force is not necessary even once the surface protective film is peeled, 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 x 10 + ¹¹ ? /? Or less and a peeling electrification voltage of 占 0 to 0.5 kV. In the present invention, "± 0 to 0.5 kV" means 0 to 0.5 kV and 0 to + 0.5 kV, that is, -0.5 to +0.5 kV. When the surface resistivity is high, the performance for escaping the static electricity generated by the charging at the time of peeling is lowered. Therefore, by sufficiently reducing the surface resistivity, the peeling electrification voltage caused by the static electricity generated when the adherend is peeled off is reduced Thus, it is possible to suppress the influence on the electric control circuit of the adherend or the like.

The gel fraction of the pressure-sensitive adhesive layer (pressure-sensitive adhesive after crosslinking) obtained by crosslinking the pressure-sensitive adhesive composition of the present invention is preferably 95 to 100%. As described above, the high gel fraction lowers the adhesive force at a low rate of peeling, reduces elution of the unpolymerized monomer or oligomer from the copolymer, and improves the reworkability and durability at high temperature and high humidity, The contamination of the complex 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 (F) 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 and high- , Durability performance and reworkability (no stain on the adherend after the surface protective film is overlaid with the ballpoint pen through the pressure-sensitive adhesive layer) is also excellent. Therefore, it can be preferably used as a surface protective film of a polarizing plate.

In the adhesive film and the surface protective film according to the present invention, a polyester film or the like can be used as the base material of the resin film and the release film (separator) for protecting the pressure-sensitive adhesive layer.

The resin film may be subjected to an antifouling treatment with a silicone, a fluorine-based releasing agent, a coating agent, a silica fine particle or the like, or an antistatic treatment by application or incorporation of an antistatic agent on the side opposite to the side where the pressure- .

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

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. Thereafter, 100 parts by weight of 2-ethylhexyl acrylate and 3.5 parts by weight of 8-hydroxyoctyl acrylate were added to the reactor. 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 (1) of Example 1 having a weight average molecular weight of 500,000 . A part of the acrylic copolymer was sampled and used as a sample for measuring the acid value described later.

[Examples 2 to 6 and Comparative Examples 1 to 3]

The same procedure as in the acrylic copolymer solution (1) used in Example 1 was carried out except that the monomers were prepared as described in (A), (B), (I) and (F- Acrylic copolymer solutions used in Examples 2 to 6 and Comparative Examples 1 to 3 were obtained.

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

[Example 1]

1.5 parts by weight of 1-octylpyridinium hexafluorophosphate and 4.0 parts by weight of acetylacetone were added to the acrylic copolymer solution (1) of Example 1 prepared as described above, followed by stirring. Coronate HX (hexamethylene diisocyanate , 1.5 parts by weight of isocyanurate compound and 0.05 part by weight of tris (2,4-pentanedionate) iron (III) 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 6 and Comparative Examples 1 to 3]

The surface protective films of Examples 2 to 6 and Comparative Examples 1 to 3 were prepared in the same manner as in the surface protective film of Example 1 except that the additive compositions were changed as described in (C) to (F) and (J) A surface protective film was obtained.

Table 1 and Table 2 show the values of the parts by weight obtained by dividing all the tables showing the blending ratios of the respective components by two and calculating the total of the group (A) as 100 parts by weight in parentheses. The values of the ratio of (E) / (D) are shown in Table 3. Table 4 and Table 5 show the chemical names of the weak symbols of the respective components used in Tables 1 and 2. D-140N, D-127N, and D-110N are trade names of Mitsui Chemicals, Inc., and Death Modules (trade names) are trade names of Nippon Polyurethane Industry Co., (Registered trademark) N3400 is a trade name of Sumika Bayer Urethane Co., Ltd.

In Table 1, in the antistatic agent (F), the ionic compound containing the (F-2) acryloyl group copolymerized in the copolymer is described in a column separate from the antistatic agent (F) added after polymerization.

<Synthesis of bifunctional isocyanate compound>

The bifunctional isocyanate compounds of Synthesis Examples 1 and 2 were synthesized in the following manner.

As shown in Table 6 and Table 7, the diisocyanate and the diol compound were mixed at a molar ratio of NCO / OH = 16, and the mixture was reacted at 120 ° C for 3 hours. Thereafter, Of diisocyanate was removed to obtain a desired bifunctional isocyanate compound.

<Test Method and Evaluation>

After the surface protective films of Examples 1 to 6 and Comparative Examples 1 to 3 were aged for 7 days in an atmosphere of 23 ° C and 50% RH, a release film (PET film coated with silicone resin) was peeled off to expose the pressure- Was used as a sample for measuring 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.

<Adhesion>

The test specimen obtained by bonding the surface of the polarizing plate with the surface protective film having a width of 25 mm was stretched in the direction of 180 DEG at a low speed peeling speed (0.3 m / min) and a high speed peeling speed (30 m / min) And peel strength measured as the adhesive force.

<Surface resistivity>

After aging, a releasing film (PET resin film coated with a silicone resin) was peeled off to form a pressure-sensitive adhesive layer before being adhered to the polarizing plate, and the pressure-sensitive adhesive layer was exposed using a resistivity meter Hiresta UP-HT450 (manufactured by Mitsubishi Chemical Corporation) The surface resistivity was measured.

<Peeling Voltage>

The voltage (high voltage) generated when the polarizing plate was charged by 180 ° peeling at a tensile speed of 30 m / min was measured using a high-precision electrostatic sensor SK-035, SK-200 (manufactured by Keyes Corporation) , And the maximum value of the measured value was taken as the peeling electrification voltage.

<Workability>

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

<Portlife>

Of (C) ~ (F) and (J) after the measurement of the viscosity η ₀ (initial viscosity) of the adhesive composition immediately after combination of additives, and allowed to stand again 23 ℃ × 8 hours of pressure-sensitive adhesive composition to a sealed pressure-sensitive adhesive composition of the The viscosity? ₁ (viscosity after 8 hours) was measured. The ratio of the value of eta ₁ , that is, the ratio of eta ₁ / eta _{0 to} the value of eta ₀ as an index of pot life was obtained. The evaluation target standard was evaluated as &quot;?&Quot; when the viscosity after 8 hours was less than 1.25 times the initial viscosity, &quot;?&Quot; when the viscosity was 1.25 times or more and 1.50 times or less, Respectively.

<Durability>

The sample thus obtained was allowed to stand in an atmosphere at 60 DEG C and 90% RH for 250 hours, taken out to room temperature, left for another 12 hours, and then measured for adhesion, and it was confirmed that there was no apparent increase compared with the initial adhesion. 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 8 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 6 had an adhesive force of 0.05 to 0.1 N / 25 mm at a low speed peeling rate of 0.3 m / min, an adhesive force of 1.0 N / 25 mm or less at a high peeling rate of 30 m / Of 9.0 × 10 + ¹¹ Ω / □ or less, peeling electrification voltage of ± 0 to 0.5 kV, and the surface protection film is covered with a ball pen through the pressure-sensitive adhesive layer, there is no contamination on the adherend, the port life is long, Deg.] C and 90% RH for 250 hours.

That is, it has an antistatic property, has excellent balance of adhesive force at a low speed peeling speed and a high speed peeling speed, has a long pot life, and is excellent in durability and reworkability.

Further, according to the surface protecting films of Examples 1 to 6, since the organotin compound is not contained in the pressure-sensitive adhesive composition, safety is high.

The surface protective film of Comparative Example 1 had a too large adhesive force at a low speed peeling rate of 0.3 m / min and a high peeling rate of 30 m / min because it did not contain (C) a bifunctional or higher isocyanate compound serving as a crosslinking agent, And the peeling electrification voltage was high, and the reworkability and durability were poor.

The surface protective film of Comparative Example 2 had a high peeling electrification voltage, short pot life, and poor durability because of the small ratio of the (E) ketoene tautomeric compound to the crosslinking catalyst of the metal chelate compound (D) .

Since the ratio of the (E) ketoene tautomeric compound to the crosslinking catalyst of (D) the metal chelate compound was small in the surface protective film of Comparative Example 3, the port life was too short and the crosslinking proceeded before coating, I could not do it.

As described above, the surface protective films of Comparative Examples 1 to 3 had an antistatic property, excellent balance of adhesive force at a low speed peeling speed and a high speed peeling speed, and a long port life and excellent durability and workability All required performance can not be satisfied at the same time.

Claims (12)

(C) relative to 100 parts by weight of a copolymer of a copolymerizable monomer containing a hydroxyl group (B) as a copolymerizable monomer group with at least one (meth) acrylate monomer having an alkyl group of C4 to C18 in the alkyl group (A) 0.1 to 10 parts by weight of a bifunctional or higher functional isocyanate compound, (D) 0.001 to 0.5 part by weight of a crosslinking catalyst of a metal chelate compound, (E) 0.1 to 200 parts by weight of a ketoene tautomer compound, (F) 0.05 to 5 parts by weight of an ionic compound having a melting point of 25 to 50 DEG C, and a ratio by weight of (E) / (D) of 70 to 700. The method according to claim 1,
(Meth) acrylate, 4-hydroxybutyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, Sensitive adhesive composition comprising at least one compound selected from the group consisting of ethyl (meth) acrylate, N-hydroxy (meth) acrylamide, N-hydroxymethyl (meth) acrylamide and N-hydroxyethyl . 3. The method according to claim 1 or 2,
Examples of the bifunctional isocyanate compound (C) as the bifunctional or higher functional isocyanate compound include a non-cyclic aliphatic isocyanate compound, a compound produced by reacting a diisocyanate compound and a diol compound, the diisocyanate compound is an aliphatic diisocyanate, Methylene-1,3-propanediol, 2-methyl-1,3-propanediol, 2-methyl-1,3-propanediol, 2-methyl-1,3-propanediol and the like can be used as a diol compound selected from the group consisting of methylene diisocyanate, pentamethylene diisocyanate, hexamethylene diisocyanate, trimethylhexamethylene diisocyanate, Propylene-1,3-propanediol, 2-ethyl-2-butyl-1,3-propanediol, 3-methyl- Pentanediol, 2,2-dimethyl-1,3-propanediol monohydroxypivalate, polyethylene glycol, and polypropylene glycol. 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 isophorone diisocyanate compound An isocyanurate of a xylylene diisocyanate compound, an isocyanurate of a xylylene diisocyanate compound, a burette of an isophorone diisocyanate compound, an isocyanurate of a tolylene diisocyanate compound, an isocyanurate of a xylylene diisocyanate compound, A pressure-sensitive adhesive composition comprising 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. 3. The method according to claim 1 or 2,
Wherein the crosslinking catalyst in the pressure-sensitive adhesive composition is at least one selected from the group consisting of an aluminum chelate compound, a titanium chelate compound, and an iron chelate compound. 3. The method according to claim 1 or 2,
Wherein the antistatic agent (F) is an ionic compound having a melting point of 25 to 50 占 폚, wherein the antistatic agent is contained in an amount of 0.05 to 5.0 parts by weight based on 100 parts by weight of the copolymer; and / Containing compound is an ionic compound containing a nitro group. 3. The method according to claim 1 or 2,
Wherein the copolymer contains at least one or more of a carboxyl group-containing monomer, a nitrogen-containing vinyl monomer not containing a hydroxyl group, and a polyalkylene glycol mono (meth) acrylate monomer as the other copolymerizable monomer group, and / A polyether siloxane compound, and other conventional antioxidants. 3. The method according to claim 1 or 2,
Wherein the pressure-sensitive adhesive layer formed by crosslinking the pressure-sensitive adhesive composition has an adhesive force of 0.05 to 0.1 N / 25 mm at a low speed peeling speed of 0.3 m / min and an adhesive force of 1.0 N / 25 mm or less at a high speed peeling speed of 30 m / min. 3. The method according to claim 1 or 2,
Wherein the pressure-sensitive adhesive layer formed by crosslinking the pressure-sensitive adhesive composition has a surface resistivity of 9.0 10 + ¹¹ ? /? Or less and a peeling electrification voltage of +/- 0 to 0.5 kV. 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 claim 1 or 2 on one side of a resin film, characterized in that after the surface protective film is covered with a ballpoint pen through the pressure sensitive adhesive layer, No surface protection film. 11. The method of claim 10,
A surface protective film used as a surface protective film of a polarizing plate. 12. The method of claim 11,
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.