KR20160108289A - Adhesive composition and surface protection film - Google Patents

Abstract

The present invention relates to an adhesive composition having antistatic property, a high balance of adhesive force at a low peel rate and high peel rate and excellent port life, durability and reworkability, and a surface protection film. The adhesive composition comprises: (A) a C4-C18 alkyl (meth)acrylate monomer; a copolymeric acrylic polymer including (B) a hydroxyl group-containing copolymerizable monomer; (C) a carboxyl group-containing copolymerizable monomer; (D) a polyalkylene glycol mono(meth)acrylate monomer; (E) a hydroxyl group-free nitrogen-containing vinyl monomer or alkoxy group-containing alkyl (meth)acrylate monomer; (F) a difunctional or higher functional isocyanate compound; (G) a crosslinking accelerator of a metal chelate compound; (H) a keto-enol tautomreic compound; (I) an antistatic agent; and (J) a polyether-modifed siloxane compound.

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 copolymerization with an acrylic monomer having a hydroxyl group or a carboxyl group 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 or the like is preferably used for a pressure-sensitive adhesive which is excellent in 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 . 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 cheap substitute for a dibutyltin compound used in combination with an isocyanate crosslinking agent and has an excellent reaction rate of the crosslinking reaction. However, it is difficult to find a crosslinking catalyst.

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 used in combination to stop the crosslinking reaction until the time of starting the crosslinking reaction after the raw material of the pressure-sensitive adhesive composition is blended.

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.

Disclosure of the Invention The present invention has been made in view of the above circumstances and has an object of providing an antistatic coating composition which does not use an organotin compound and which has an antistatic property and is excellent in balance of adhesive force at a low rate of peeling and a high rate of peeling, And a pressure-sensitive adhesive composition for a surface protective film of a polarizing plate excellent in reworkability and a surface protective film.

(A) a monomer copolymerizable with at least one of (meth) acrylic acid ester monomers having an alkyl group having from 4 to 18 carbon atoms, (B) a copolymerizable monomer containing a hydroxyl group, (C) a carboxyl group-containing copolymerizable monomer, (D) a polyalkylene glycol mono (meth) acrylate monomer, and (E) a nitrogen-containing vinyl monomer or alkoxy group-containing alkyl (F) a crosslinking accelerator of a bifunctional or higher isocyanate compound, (G) a metal chelate compound, (H) a ketoene (I) an ionic compound having a melting point of 25 to 50 DEG C as an antistatic agent and / or an ionic compound containing an acryloyl group And (J) a polyether-modified siloxane compound.

Further, with respect to 100 parts by weight in total 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 the copolymerizable monomer containing the hydroxyl group (B)

0 to 1.0 part by weight of the copolymerizable monomer containing the carboxyl group (C)

0 to 50 parts by weight of (D) the polyalkylene glycol mono (meth) acrylate monomer,

(E) 0 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 (B) isocyanate compound having two or more functional groups,

0.001 to 0.5 parts by weight of the crosslinking accelerator of the metal chelate compound (G)

And 0.1 to 200 parts by weight of the (H) ketoene tautomer compound,

As the (I) antistatic agent, 0.05 to 5.0 parts by weight of the total of the antistatic agent contained in the pressure-sensitive adhesive composition and the antistatic agent copolymerized in the copolymer,

It is preferable to contain 0.01 to 1.0 part by weight of the (J) polyether-modified siloxane compound.

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 copolymerizable monomer containing (C) a carboxyl group is preferably selected from the group consisting of (meth) acrylic acid, carboxyethyl (meth) acrylate, carboxypentyl (meth) acrylate, 2- (meth) acryloyloxyethylhexahydrophthalic acid, (Meth) acryloyloxyethyl methacrylate, 2- (meth) acryloyloxyethyl methacrylate, 2- (meth) acryloyloxyethyl methacrylate, 2- At least one member selected from the group consisting of carboxypolycaprolactone mono (meth) acrylate and 2- (meth) acryloyloxyethyltetrahydrophthalic acid is preferable.

Also, when the polyalkylene glycol mono (meth) acrylate monomer (D) is a polyalkylene glycol mono (meth) acrylate, methoxypolyalkylene glycol (meth) acrylate, ethoxypolyalkylene glycol Acrylate, and the like.

In addition, it is preferable that the acrylic polymer includes at least one nitrogen-containing vinyl monomer or alkoxy group-containing alkyl (meth) acrylate monomer (E) that does not contain a hydroxyl group as the copolymerizable monomer group.

The bifunctional isocyanate compound (F) 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 (F) 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 antistatic agent (I) is an ionic compound having a melting point of 25 to 50 占 폚, which is contained in an amount of 0.1 to 5.0 parts by weight based on 100 parts by weight of the copolymer, and / or the copolymer is contained in an amount of 0.1 to 5.0% It is preferably an ionic compound containing a copolymerized acryloyl group.

The HLB value of the polyether-modified siloxane compound (J) is preferably 7 to 15.

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.

It is also preferable that the pressure-sensitive adhesive layer formed by crosslinking the pressure-sensitive adhesive composition has a surface resistivity of 9.0 x 10 ⁺ 10? /? Or less and a peeling electrification voltage of 占 0 to 0.5 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 surface of a resin film, wherein the surface protective film is covered with a ballpoint pen through the pressure- Is provided on the surface of the substrate.

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 the performance required for the pressure-sensitive adhesive layer of the surface protective film without using an organotin compound, which can not be solved by the prior art, It has become possible to prevent the occurrence. 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.

(A) a monomer copolymerizable with at least one of (meth) acrylic acid ester monomers having an alkyl group of C4 to C18 in the alkyl group, (B) a copolymerizable monomer containing a hydroxyl group, (C) (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 crosslinking accelerator of a bifunctional or higher-functional isocyanate compound, (G) a metal chelate compound, (H) a keto-enol ternary copolymer (I) an ionic compound having a melting point of 25 to 50 占 폚 and / or an ionic compound containing an acryloyl group as an antistatic agent It characterized in that it additionally contains water and, (J) a polyether modified siloxane compound.

(A) 50 to 95 parts by weight of a (meth) acrylic acid ester monomer having an alkyl group in which the number of carbon atoms is in the range of C4 to C18, and (B) an acrylic polymer having a hydroxyl group (C) 0 to 1.0 part by weight of a copolymerizable monomer containing a carboxyl group, (D) 0 to 50 parts by weight of a polyalkylene glycol mono (meth) acrylic acid ester monomer, and , And (E) 0 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.

(F) 0.1 to 10 parts by weight of the bifunctional or higher functional isocyanate compound, (G) 0.001 to 0.5 part by weight of the (G) crosslinking accelerator of the metal chelate compound, And (H) 0.1 to 200 parts by weight of a ketone-enol tautomeric compound, and wherein (I) an antistatic agent as an antistatic agent and an antistatic agent copolymerized in the above- And (J) 0.01 to 1.0 part by weight of the polyether-modified siloxane compound.

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 95 parts by weight, when the total amount of the acrylic polymer of the copolymer is 100 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.

When the total amount of the acrylic polymer of the copolymer is 100 parts by weight, it is preferable that the copolymerizable monomer containing the hydroxyl group (B) is contained in a proportion of 0.1 to 10 parts by weight.

(Meth) acrylic acid, carboxyethyl (meth) acrylate, carboxypentyl (meth) acrylate, 2- (meth) acryloyloxyethylhexahydrophthalic acid, 2- ) Acryloyloxyethyl methacrylate, 2- (meth) acryloyloxyethyl methacrylate, 2- (meth) acryloyloxyethyl methacrylate, 2- At least one member selected from the group consisting of lactone mono (meth) acrylate and 2- (meth) acryloyloxyethyl tetrahydrophthalic acid is preferable.

When the total amount of the acrylic polymer of the copolymer is 100 parts by weight, it is preferable that the copolymerizable monomer containing the carboxyl group (C) is contained at a ratio of 0 to 1.0 part by weight. In the pressure-sensitive adhesive layer according to the present invention, a copolymerizable monomer containing a carboxyl group (C) may not be contained in the pressure-sensitive adhesive 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.

(D) the average number of repeats of the alkylene oxide constituting the polyalkylene glycol chain of the polyalkylene glycol mono (meth) acrylic acid ester monomer is preferably 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.

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.

It is preferable that the polyalkylene glycol mono (meth) acrylate monomer (D) is contained in an amount of 0 to 50 parts by weight, based on 100 parts by weight of the total of the acrylic polymer of the copolymer. In the pressure-sensitive adhesive layer according to the present invention, (D) a polyalkylene glycol mono (meth) acrylic acid ester monomer may not be contained in the pressure-sensitive adhesive composition.

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 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.

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-1) a nitrogen-containing vinyl monomer containing no hydroxyl group or an alkyl (meth) acrylate monomer containing an alkoxyl group (E-2) in an amount of from 0 to 20 parts by weight, based on 100 parts by weight of the total of the acrylic- 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. In the pressure-sensitive adhesive layer according to the present invention, the pressure-sensitive adhesive composition may not contain a nitrogen-containing vinyl monomer or alkoxy group-containing alkyl (meth) acrylate monomer (E)

(F) The bifunctional or higher isocyanate compound may be at least one selected from polyisocyanate compounds having at least two isocyanate (NCO) groups in one molecule, or at least two kinds thereof. 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 (F-1) trifunctional isocyanate compound or (F-2) bifunctional isocyanate compound as the (F) bifunctional or higher isocyanate compound. It is also possible to use the (F-1) trifunctional isocyanate compound and the (F-2) bifunctional isocyanate compound in combination.

Examples of the (F-1) trifunctional isocyanate compound used in the present invention include an isocyanurate of a hexamethylene diisocyanate compound, an isocyanurate of an isophorone diisocyanate compound, a compound of a hexamethylene diisocyanate compound At least one member selected from the group of (F-1-1) first aliphatic isocyanate compounds, which is 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 the second aromatic isocyanate compounds (F-1-2), which is an adduct of an adduct of aniline isocyanurate compound and an adduct of an indolinone isocyanate compound. (F-1-1) The first aliphatic isocyanate compound group and the (F-1-2) second aromatic isocyanate compound group are preferably used in combination. In the present invention, at least one kind selected from among the (F-1-1) first aliphatic isocyanate compound group and (F-1-2) second aromatic isocyanate compound group as the (F-1) trifunctional 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 (F-1) trifunctional isocyanate compound may be at least one selected from the group of the above-mentioned (F-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 the first aliphatic isocyanate compound group (F-1-1) and the second aromatic isocyanate compound group (F-1-2) is (F- 1-1) :( F-1-2) is in the range of 10%: 90% to 90%: 10% by weight.

The (F-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 (F-1 / F-2) of the (F-1) trifunctional isocyanate compound and the (F-2) bifunctional isocyanate compound is preferably 1 to 90. It is preferable that the (B) isocyanate compound having a bifunctionality of (F) is 0.1 to 10 parts by weight based on 100 parts by weight of the acryl-based polymer.

When the polyisocyanate compound is used as a crosslinking agent, the crosslinking accelerator of the metal chelate compound (G) 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 accelerator.

The metal chelate compound is a compound in which one or more Dazoid ligands L are 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 includes at least one selected from the group consisting of an aluminum chelate compound, a titanium chelate compound, an iron chelate compound, and a tin chelate compound (however, not containing TBT) .

The crosslinking accelerator of the (G) metal chelate compound 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 (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. 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- .

(H) The ketoene tautomer compound is preferably contained in an amount of 0.1 to 200 parts by weight based on 100 parts by weight of the copolymer.

(H) Ketoenol tautomeric compound (G) has an effect of inhibiting crosslinking as opposed to (G) a crosslinking accelerator of a metal chelate compound. It is preferable to appropriately set the ratio of the isomeric compound. The weight ratio of (G) :( H) is preferably in the range of 1: 1 to 1: 300, more preferably 1:30 to 1: 300, in order to lengthen the pot life of the pressure- And most preferably from 1:80 to 1: 300.

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

(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 DEG C is added to the copolymer and / or (I-2) the acryloyl group-containing ionic compound is copolymerized in the copolymer do. Since the antistatic agent (I) 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.

(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, Compounds that are inorganic or organic anions such as alkylbenzenesulfonate (RC ₆ H ₄ SO ₃ ^- ), perchlorate (ClO ₄ ^- ), and tetrafluoroborate (BF ₄ ^- ). It is preferably a solid at room temperature (for example, 25 ° C), and a melting point of 25 to 50 ° C can be obtained by selecting the chain length of the alkyl group, the position and number of the substituent, and the like. The cation is preferably a quaternary nitrogen atom onium cation, and a quaternary pyridinium cation such as 1-alkyl pyridinium (the carbon atom at the 2-6 position may have a substituent or may be unsubstituted) or 1 , 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) The ionic compound having a melting point of 25 to 50 캜 is preferably contained in an amount of 0.1 to 5.0 parts by weight based on 100 parts by weight 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 in an amount of 0.1 to 5.0% by weight.

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 may optionally contain (J) a polyether-modified siloxane compound. (J) a 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⁾ has a -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 ].

(J) The polyether-modified siloxane compound is preferably a polyether-modified siloxane compound having an HLB value of 7 to 15. Further, it is preferable that 0.01 to 1.0 part by weight of the polyether-modified siloxane compound (J) is contained relative to 100 parts by weight of the copolymer. More preferably, it is 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).

(J) 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) .

(J) The blend of the polyether-modified siloxane compound and the pressure-sensitive adhesive composition can improve the adhesive force and the workability of the pressure-sensitive adhesive. When the pressure-sensitive adhesive composition does not contain a polyether-modified siloxane compound, it becomes more inexpensive.

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 accelerator, 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) (D) a polyalkylene glycol mono (meth) acrylate monomer; and (E) a nitrogen-containing vinyl monomer or alkoxy group-containing alkyl (meth) acrylate containing no hydroxyl group. ) Acrylate monomers, which are copolymerizable with each other. 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.

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) at least one monomer selected from the group consisting of polyalkylene glycol mono (meth) acrylic acid (E) at least one member selected from the group of copolymerizable monomers comprising a nitrogen-containing vinyl monomer or an alkoxy group-containing alkyl (meth) acrylate monomer which does not contain a hydroxyl group, (I-2) Can be synthesized.

The pressure-sensitive adhesive composition of the present invention is characterized in that the above-mentioned pressure-sensitive adhesive composition comprises (F) a bifunctional or higher isocyanate compound, (G) a crosslinking accelerator of a metal chelate compound, (H) a ketoene tautomer compound, (I) an antistatic agent, An ether-modified siloxane compound, and further optionally an optional additive. When the (I-2) acryloyl group-containing ionic compound is polymerized in the copolymer of the subject, an antistatic agent (I) may be further added to the copolymer, or may not be 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 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 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 × 10 ⁺ 10 Ω / □ or less and a peeling electrification voltage of ± 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. The pressure-sensitive adhesive composition of the present invention has excellent antistatic properties because of the balanced combination of the components (A) to (J), and has excellent adhesive balance at low and high peel rates , Durability performance and reworkability (no contamination of 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.

As the base film of the pressure-sensitive adhesive layer or the release film (separator) for protecting the pressure-sensitive adhesive surface, 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. Thereafter, 100 parts by weight of 2-ethylhexyl acrylate, 3.0 parts by weight of 8-hydroxyoctyl acrylate, polypropylene glycol monoacrylate (average number of repeating units of alkylene oxide constituting the polyalkylene glycol chain n = 12) and 60 parts by weight of a solvent (ethyl acetate). 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, Reference Examples 1 to 3 and Comparative Examples 1 to 4]

The acrylic copolymer solution (1) used in Example 1 was prepared in the same manner as in the acrylic copolymer solution (1) used in Example 1 except that the monomers were changed to the compositions of (A) to (E) 6, Reference Examples 1 to 3 and Comparative Examples 1 to 4 were obtained.

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

[Example 1]

1.5 parts by weight of 1-octylpyridinium hexafluorophosphate, 0.05 part by weight of polyether-modified siloxane compound (HLB = 7) and 8.5 parts by weight of acetylacetone were added to the acrylic copolymer solution (1) , 2.0 parts by weight of Coronate HX (isocyanurate of hexamethylene diisocyanate compound) 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 6, Reference Examples 1 to 3 and Comparative Examples 1 to 4]

6, Reference Examples 1 to 3 and Comparative Example 1 were prepared in the same manner as in the surface protective film of Example 1, except that the composition of the additive was changed as shown in Table 2 (F) to (J) A surface protective film of? 4 was obtained.

Tables 1 and 2 show the results obtained by dividing all the tables showing the blending ratios of the respective components into two parts, and the values of the parts by weight obtained by taking the total of the whole (A) group as 100 parts by weight are enclosed in parentheses. 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 .; and Coronate (registered trademark) HX, HL and L are trade names of Nippon Polyurethane Industry Co., , And Desmodel (registered trademark) N3400 is a trade name of Sumika Bayer Urethane Co.,

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.

<Synthesis of bifunctional isocyanate compound>

The bifunctional isocyanate compounds of Synthesis Examples 1 to 3 were synthesized in the following manner. As shown in Tables 5 and 6, 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, a thin film evaporator was used to conduct unreacted Of diisocyanate was removed to obtain a desired bifunctional isocyanate compound.

<Test Method and Evaluation>

The surface protective films of Examples 1 to 6, Reference Examples 1 to 3 and Comparative Examples 1 to 4 were aged for 7 days under an atmosphere of 23 ° C and 50% RH, and then a release film (PET resin film coated with a silicone resin) And the pressure-sensitive adhesive layer was exposed to be 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>

The viscosity η ₀ (initial viscosity) of the pressure-sensitive adhesive composition immediately after the addition of the additives of (F) to (J) was measured, and the viscosity η ₁ of the pressure-sensitive adhesive composition after leaving the pressure- 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 7 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 and Reference Examples 1 to 3 had 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, a surface resistivity of 9.0 × 10 ^{+ 10} Ω / □ or less, and a peeling electrification voltage of ± 0 to 0.5 kV. After the surface protective film is overlaid with a ball pen through the pressure-sensitive adhesive layer, , The pot life was long, and durability was excellent when left in an atmosphere of 60 ° 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 an excessively large adhesive force at a low rate of peel rate of 0.3 m / min and a high rate of peel rate of 30 m / min because it did not contain the (F) 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 small ratio of the (H) ketoene tautomer compound to the crosslinking accelerator of the (G) metal chelate compound, and the HLB value of the (J) polyether modified siloxane compound was excessive The peeling voltage was high, the port life was slightly short, and the durability was poor.

The surface protective film of Comparative Example 3 uses a crosslinking accelerator of an organic tin compound instead of the crosslinking accelerator of the (G) metal chelate compound and the ratio of the (k) (keto) enol tautomeric compound to the crosslinking accelerator is smaller , The pot life became too short, and the crosslinking proceeded before application, so that the coating could not be performed.

The surface protective film of Comparative Example 4 did not contain all of the (G) metal chelate compound crosslinking accelerator and (H) ketoene tautomeric compound, and (J) did not contain the polyether modified siloxane compound , The adhesive force at a high speed peeling speed of 30 m / min was too large, the port life was short, and the durability was poor.

As described above, the surface protective films of Comparative Examples 1 to 4 had an antistatic property and were excellent in balance of adhesive force at a low rate of peeling and at a high rate of peeling, and had a long pot life and excellent durability and workability Can not satisfy all the required performance simultaneously.

Claims (4)

1. A surface protective film comprising a pressure-sensitive adhesive layer formed by crosslinking an acrylic polymer, (I) an antistatic agent, and (F) a pressure-sensitive adhesive composition containing a crosslinking agent,
Based on 100 parts by weight of the total of the acryl-based polymer,
(A) 50 to 95 parts by weight of at least one (meth) acrylic acid ester monomer having an alkyl group having 4 to 18 carbon atoms,
(C) a copolymerizable monomer containing a carboxyl group, (D) a polyalkylene glycol mono (meth) acrylate monomer and (B) a copolymerizable monomer containing a hydroxyl group, , (E) a nitrogen-containing vinyl monomer containing no hydroxyl group, or an alkyl (meth) acrylate monomer containing an alkoxy group containing no hydroxyl group, is copolymerized with an acryl-based polymer under,
(Meth) acrylate, 4-hydroxybutyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, At least one compound selected from the group consisting of ethyl (meth) acrylate, N-hydroxy (meth) acrylamide, N-hydroxymethyl (meth) acrylamide and N-hydroxyethyl
Wherein the pressure-sensitive adhesive composition further comprises (G) a crosslinking accelerator of a metal chelate compound, (H) a ketoene tautomeric compound, and (J) a polyether-modified siloxane compound having an HLB value of 7 to 15,
0.001 to 0.5 parts by weight of the crosslinking accelerator of the metal chelate compound (G) and 0.1 to 200 parts by weight of the ketoene enol tylosyl compound (H), relative to 100 parts by weight of the total of the acrylic polymer of the copolymer , The weight ratio of (G) :( H) is 1: 80 to 1: 300,
Wherein the (G) metal chelate compound is a titanium chelate compound or an iron chelate compound. The method according to claim 1,
Based on the total 100 parts by weight of the acrylic polymer of the copolymer,
The acrylic polymer
0 to 1.0 part by weight of the copolymerizable monomer containing the carboxyl group (C)
0 to 150 parts by weight of (D) the polyalkylene glycol mono (meth) acrylic acid ester monomer,
(E) 0 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 containing no hydroxyl group,
Wherein the pressure-sensitive adhesive composition comprises 0.1 to 10 parts by weight of a bifunctional or higher isocyanate compound as the crosslinking agent (F), 0.1 to 10 parts by weight of an isocyanate compound having a melting point of 25 to 50 DEG C 0.05 to 5.0 parts by weight of the total amount of the acrylic compound and / or the acryloyl group-containing ionic compound copolymerized in the copolymer in an amount of 0.1 to 5.0% by weight,
(J) 0.01 to 1.0 part by weight of a polyether-modified siloxane compound having an HLB value of 7 to 15. 3. The method according to claim 1 or 2,
(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 selected from the group consisting of polyvinyl alcohol and polyvinyl alcohol. 3. The method according to claim 1 or 2,
A surface protective film used as a surface protective film of a polarizing plate.