JP2022066542A - Pressure sensitive adhesive layer, pressure sensitive adhesive film, and surface protective film - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide: a pressure sensitive adhesive layer that has an anti-static performance, is excellent in a balance between adhesive forces in low-speed and high-speed peel rates, has a long pot life, and is also excellent in durability and reworkability; a pressure sensitive adhesive film; and a surface protective film.

SOLUTION: The pressure sensitive adhesive layer includes: an acrylic polymer of a copolymer having an acid value of 0.01 to 8.0, which contains (A) a (meth)acrylic acid ester monomer having 4 to 18 carbon atoms in an alkyl group, (B) a monomer containing a hydroxyl group, (C) a monomer containing a carboxyl group, (D) a polyalkylene glycol mono(meth)acrylic acid ester monomer, and (E) a nitrogen-containing vinyl monomer or an alkoxy group-containing alkyl(meth)acrylate monomer, any of which does not contain a hydroxyl group; (F) an isocyanate compound having 2 or more functional groups; (G) a cross-linking catalyst of a metal chelate compound; (H) a keto-enol tautomeric isomer compound; (I) an anti-static agent; (J) a polyether-modified siloxane compound; and (K) an antioxidizing agent.

SELECTED DRAWING: None

COPYRIGHT: (C)2022,JPO&INPIT

Description

The present invention relates to an adhesive film and a surface protective film. More specifically, the surface of a polarizing plate having antistatic performance, an excellent balance of adhesive strength at a low peeling speed and a high peeling speed, a long pot life, and excellent durability and reworkability. The present invention relates to providing an adhesive film for a protective film and a surface protective film.

Since the pressure-sensitive adhesive for optical use has excellent transparency, it is a copolymer obtained by copolymerizing an alkyl (meth) acrylate as a main component with an acrylic monomer having a hydroxyl group, a carboxyl group, etc. as a functional group. An acrylic pressure-sensitive adhesive comprising the above is preferably used. Further, it is required that various physical properties such as the adhesive strength of the adhesive are appropriately adjusted. In particular, adhesives for surface protective films have a low peeling speed and a high peeling speed, which are suitable for bonding surface protective films with an automatic bonding device so that they can be adapted to factory-produced manufacturing processes. There is a demand for an adhesive having an excellent balance of adhesive strength. Further, in addition to the balance of adhesive strength, there is a need for an adhesive having a long pot life and excellent durability, reworkability, and antistatic property.

For such various physical properties of the pressure-sensitive adhesive, an isocyanate-based cross-linking agent, an epoxy-based cross-linking agent, etc. that react with functional groups such as hydroxyl groups and carboxyl groups contained in the acrylic pressure-sensitive adhesive made of a copolymer are used. The cross-linking reaction is carried out to adjust the adhesive force and the cohesive force.

Conventionally, an isocyanate-based cross-linking agent has been generally used as a cross-linking agent for an acrylic pressure-sensitive adhesive. Further, in the cross-linking reaction using an isocyanate-based cross-linking agent, a metal chelate is often used as a catalyst for promoting the cross-linking reaction.
In general, dibutyltin dilaurate, which is an organotin compound, has been used as a catalyst for the cross-linking reaction because the reaction rate of the cross-linking reaction is excellent. However, since the dibutyl-tin compound exhibits harmful toxicity. It is avoided to use.
Therefore, there has been a demand for a cross-linking catalyst that is inexpensive and has an excellent reaction rate for the cross-linking reaction, which is an alternative to the dibutyltin compound used in combination with the isocyanate-based cross-linking agent, but it has been difficult to find.

Under these circumstances, Patent Document 1 discloses that iron chelate is preferable as a cross-linking catalyst used in combination with an isocyanate-based cross-linking agent, and tris (acetylacetonate) iron is particularly preferable because it has excellent catalytic activity. There is.

By the way, in the acrylic pressure-sensitive adhesive composition containing a crosslinking catalyst, the crosslinking reaction gradually proceeds even while it is left at room temperature. Therefore, in the industrial production of pressure-sensitive adhesives, after blending the raw materials of the pressure-sensitive adhesive composition, a cross-linking catalyst and a reaction retarder are used in order to stop the cross-linking reaction until the time when the cross-linking reaction is generally started. Is used together.
Regarding the combined use of this cross-linking catalyst and the reaction retarder, Patent Document 2 describes a method for producing polyurethane, which comprises a mixture of at least one kind of metal acetylacetonate and acetylacetone, and the metal acetylacetonate and the acetylacetone. It is disclosed to use a reactive urethane mixture containing a catalytic system having a weight ratio of 2: 1.

Japanese Unexamined Patent Publication No. 2011-001440 Japanese Unexamined Patent Publication No. 2008-285681

In the pressure-sensitive adhesive composition described in Patent Document 1, the amount of the metal compound (crosslinking catalyst) added to the copolymer containing (meth) acrylate as a constituent monomer unit and containing a hydroxyl group and a carboxyl group is shown. However, there is no description about the amount of the cross-linking retarder added. Further, Patent Document 1 describes a method of using a reaction retarder, a method of adding a viscosity increase suppressing solvent, a functionality of blocked isocyanate and the like as a method of suppressing the viscosity increase rate after adding a cross-linking agent to the pressure-sensitive adhesive composition. A method of using a cross-linking agent that blocks a group is mentioned, but there is no specific explanation.

Further, in Patent Document 2, a metal having excellent stability and good catalytic activity, which does not bring about premature curing even when a metal acetylacetonate catalyst such as iron or copper having very high activity at a low temperature is used. A method for producing polyurethane using a catalytic system containing acetylacetonate and acetylacetone is disclosed.
However, in the method described in Patent Document 2, the weight ratio of metal acetylacetonate to acetylacetone is 2: 1. However, even if this compounding ratio is applied to the manufacturing process of an acrylic pressure-sensitive adhesive, the crosslinking reaction is temporary. Could not make a stop.

The present invention has been made in view of the above circumstances, has antistatic performance without using an organic tin compound, and has an excellent balance of adhesive strength at a low peeling speed and a high peeling speed. Further, it is an object of the present invention to provide an adhesive film and a surface protective film for a surface protective film of a polarizing plate having a long pot life and excellent durability and reworkability.

In order to solve the above problems, the present invention comprises forming a pressure-sensitive adhesive layer on one or both sides of a resin film, and a release film having a silicone-based release agent layer is bonded onto the pressure-sensitive adhesive layer. It is an adhesive film made of
The pressure-sensitive adhesive layer comprises cross-linking a pressure-sensitive adhesive composition containing an acrylic polymer and a cross-linking agent.
The acrylic polymer is based on 100 parts by weight of the total amount of the acrylic polymer.
(A) At least one kind of (meth) acrylic acid ester monomer having an alkyl group having C4 to C18 carbon atoms is 50 to 95 parts by weight.
(B) 0.1 to 10 parts by weight of a copolymerizable monomer containing a hydroxyl group,
(C) 0.1 to 1.0 parts by weight of a copolymerizable monomer containing a carboxyl group,
As a group of copolymerizable monomers, (D) polyalkylene glycol mono (meth) acrylate or polyalkylene glycol alkyl ether (meth) acrylate is used in an amount of 0 to 50 parts by weight, and (E) a nitrogen-containing vinyl monomer or hydroxyl group containing no hydroxyl group is used. An alkoxy group-containing alkyl (meth) acrylate monomer containing 0 to 20 parts by weight, and at least one copolymerizable monomer selected from the copolymerizable monomer group consisting of 0 to 20 parts by weight,
It is composed of an acrylic polymer of a copolymer having an acid value of 0.01 to 8.0 obtained by copolymerizing the above.
The copolymerizable monomer containing the (B) hydroxyl group is 8-hydroxyoctyl (meth) acrylate, 6-hydroxyhexyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, or 2-hydroxyethyl (meth) acrylate. , N-Hydroxy (meth) acrylamide, N-hydroxymethyl (meth) acrylamide, and N-hydroxyethyl (meth) acrylamide, which are at least one selected from the compound group.
The pressure-sensitive adhesive composition contains 0.1 to 10 parts by weight of the (F) bifunctional or higher functional isocyanate compound as the cross-linking agent and (G) the metal chelate compound with respect to 100 parts by weight of the total of the acrylic polymers. Contains 0.001 to 0.5 parts by weight of the cross-linking catalyst of the above and 0.1 to 200 parts by weight of the (H) ketoenol tautovarious compound, and the (H) ketoenol tautovariant compound. / (G) The weight ratio (H) / (G) of the cross-linking catalyst of the metal chelate compound is 1 to 700.
The pressure-sensitive adhesive composition further contains (I) an antistatic agent, (J) a polyether-modified siloxane compound, and (K) an antioxidant.
The (K) antioxidant is a tocopherol-based antioxidant, and the tocopherol-based compound as the antioxidant is d-α-tocopherol, dl-α-tocopherol, d-β-tocopherol, dl-β-. Tocopherol, d-γ-tocopherol, dl-γ-tocopherol, d-δ-tocopherol, dl-δ-tocopherol, d-α-tocotrienol, dl-α-tocotrienol, d-β-tocotrienol, dl-β-tocotrienol, Provided is an adhesive film characterized by being at least one selected from the compound group consisting of d-γ-tocotrienol, dl-γ-tocotrienol, d-δ-tocotrienol, and dl-δ-tocotrienol.

Further, with respect to 100 parts by weight of the total acrylic polymer of the copolymer.
The acrylic polymer is
50 to 95 parts by weight of the (meth) acrylic acid ester monomer having C4 to C18 carbon atoms in the (A) alkyl group.
(B) 0.1 to 10 parts by weight of the copolymerizable monomer containing a hydroxyl group and
(C) 0.1 to 1.0 parts by weight of the copolymerizable monomer containing a carboxyl group and
0 to 50 parts by weight of the (D) polyalkylene glycol mono (meth) acrylate or polyalkylene glycol alkyl ether (meth) acrylate,
(E) 0 to 20 parts by weight of the nitrogen-containing vinyl monomer containing no hydroxyl group or the alkoxy group-containing alkyl (meth) acrylate monomer containing no hydroxyl group.
The pressure-sensitive adhesive composition
0.1 to 10 parts by weight of the above (F) bifunctional or higher functional isocyanate compound,
0.001 to 0.5 parts by weight of the cross-linking catalyst of the (G) metal chelate compound and
0.1 to 200 parts by weight of the (H) keto-enol tautomer compound and the weight ratio of the cross-linking catalyst of the (H) keto-enol tautomer compound / (G) metal chelate compound. (H) / (G) is 1 to 700, and further
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. When,
0.01 to 1.0 parts by weight of the (J) polyether-modified siloxane compound and
The (K) antioxidant contains 0.01 to 5 parts by weight of a tocopherol-based antioxidant.
The tocopherol compounds as antioxidants are d-α-tocopherol, dl-α-tocopherol, d-β-tocopherol, dl-β-tocopherol, d-γ-tocopherol, dl-γ-tocopherol, d-δ. -Tocopherol, dl-δ-tocotrienol, d-α-tocotrienol, dl-α-tocotrienol, d-β-tocotrienol, dl-β-tocotrienol, d-γ-tocotrienol, dl-γ-tocotrienol, d-δ-tocotrienol , Dl-δ-tocotrienol, preferably at least one selected from the group of compounds.

Further, the copolymerizable monomer containing the (C) carboxyl group is (meth) acrylic acid, carboxyethyl (meth) acrylate, carboxypentyl (meth) acrylate, 2- (meth) acryloyloxyethyl hexahydrophthal. Acid, 2- (meth) acryloyloxypropyl hexahydrophthalic acid, 2- (meth) acryloyloxyethyl phthalic acid, 2- (meth) acryloyloxyethyl succinic acid, 2- (meth) acryloyloxyethyl maleine At least one selected from the group of compounds consisting of acid, carboxypolycaprolactone mono (meth) acrylate, and 2- (meth) acryloyloxyethyl tetrahydrophthalic acid.
The (D) polyalkylene glycol mono (meth) acrylate or polyalkylene glycol alkyl ether (meth) acrylate has an average number of repetitions of the alkylene oxide constituting the polyalkylene glycol chain of 3 to 14, and the polyalkylene glycol mono (meth). ) At least one selected from acrylate, polyalkylene glycol methyl ether (meth) acrylate, and polyalkylene glycol ethyl ether (meth) acrylate.

Further, it is preferable that the acrylic polymer contains at least one or more of the (E) hydroxyl group-free nitrogen-containing vinyl monomer or the alkoxy group-containing alkyl (meth) acrylate monomer as the copolymerizable monomer group.

Further, as the (F) bifunctional or higher functional isocyanate compound, the bifunctional isocyanate compound is preferably an acyclic aliphatic isocyanate compound, which is a compound produced by reacting a diisocyanate compound with a diol compound. The diisocyanate compound is an aliphatic diisocyanate, and preferably consists of one selected from the compound 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, 2-methyl-2-propyl-1,3-propanediol, and 2-ethyl. A group of compounds consisting of -2-butyl-1,3-propanediol, 3-methyl-1,5-pentanediol, 2,2-dimethyl-1,3-propanediol monohydroxypivalate, polyethylene glycol, and polypropylene glycol. It is preferably composed of one selected from the above.
Further, as the above-mentioned (F) bifunctional or higher functional isocyanate compound, the trifunctional isocyanate compound includes an isocyanurate form of a hexamethylene diisocyanate compound, an isocyanurate form of an isophorone diisocyanate compound, an adduct form of a hexamethylene diisocyanate compound, and an isophorone diisocyanate compound. Adduct, hexamethylene diisocyanate compound bullet, isophorone diisocyanate compound bullet, tolylene diisocyanate compound isocyanurate, xylylene diisocyanate compound isocyanurate, hydrogenated xylylene diisocyanate compound isocyanurate, tolylene diisocyanate It is preferably at least one selected from the compound group consisting of the adduct body of the compound, the adduct body of the xylylene diisocyanate compound, and the adduct body of the hydrogenated xylylene diisocyanate compound.

Further, the (I) antistatic agent is an ionic compound having a melting point of 25 to 50 ° C., which is contained in an amount of 0.1 to 5.0 parts by weight with respect to 100 parts by weight of the copolymer. / Or, it is preferably an acryloyl group-containing ionic compound copolymerized in the copolymer by 0.1 to 5.0% by weight.

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

Further, it is preferable that the cross-linking catalyst in the pressure-sensitive adhesive composition does not contain an organic tin compound.

Further, the pressure-sensitive adhesive force of the pressure-sensitive adhesive layer obtained by cross-linking the pressure-sensitive adhesive composition at a low-speed peeling speed of 0.3 m / min is 0.05 to 0.1 N / 25 mm, and the high-speed peeling speed is 30 m / min. The adhesive strength is preferably 1.0 N / 25 mm or less.

Further, it is preferable that the surface resistivity of the pressure-sensitive adhesive layer obtained by cross-linking the pressure-sensitive adhesive composition is 9.0 × 10 ⁺¹¹ Ω / □ or less, and the peeling band voltage is ± 0 to 0.5 kV.

The present invention also provides a surface protective film characterized by using the pressure-sensitive adhesive film.

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

Further, it is preferable that the surface protective film of the present invention is antistatic and antifouling treated on the surface of the resin film opposite to the side on which the pressure-sensitive adhesive layer is formed.

According to the present invention, all the performances required for the pressure-sensitive adhesive layer of the surface protective film, which could not be solved by the prior art, can be satisfied without using an organic tin compound, and moreover, they can be satisfied. Excellent antistatic performance was obtained, and it became possible to prevent the generation of adhesive residue. Specifically, while maintaining excellent antistatic performance, the amount of antistatic agent added can be reduced, and the performance of preventing the generation of adhesive residue can be further improved.

Hereinafter, the present invention will be described based on a preferred embodiment.
The pressure-sensitive adhesive composition of the present invention has (A) a hydroxyl group as a group of monomers copolymerizable with at least one of (meth) acrylic acid ester monomers having an alkyl group having C4 to C18 carbon atoms. Containing copolymerizable monomer, (C) copolymerizable monomer containing carboxyl group, (D) polyalkylene glycol mono (meth) acrylic acid ester monomer, (E) nitrogen-containing vinyl containing no hydroxyl group Acrylic based copolymer having an acid value of 0.01 to 8.0, which comprises a monomer or an alkoxy group-containing alkyl (meth) acrylate monomer and at least one selected from a copolymerizable monomer group consisting of the monomer or an alkoxy group-containing alkyl (meth) acrylate monomer. It is composed of a polymer, and has a melting point of 25 as (F) a bifunctional or higher isocyanate compound, (G) a cross-linking catalyst of a metal chelate compound, (H) a ketoenol copolymer compound, and (I) an antistatic agent. It is characterized by containing an ionic compound having a temperature of about 50 ° C. and / or an acryloyl group-containing ionic compound, a (J) polyether-modified siloxane compound, and (K) an antioxidant.
Further, the acrylic polymer has 50 to 95 parts by weight of the (meth) acrylic acid ester monomer having (A) alkyl groups having C4 to C18 carbon atoms with respect to 100 parts by weight of the total of the acrylic polymers of the copolymer. And (B) 0.1 to 10 parts by weight of the copolymerizable monomer containing a hydroxyl group, and (C) 0.1 to 1.0 part by weight of the copolymerizable monomer containing a carboxyl group. D) 0 to 50 parts by weight of the polyalkylene glycol mono (meth) acrylic acid ester monomer, and (E) 0 to 20 parts by weight of the nitrogen-containing vinyl monomer containing no hydroxyl group or the alkoxy group-containing alkyl (meth) acrylate monomer. Is preferably contained.
Further, the pressure-sensitive adhesive composition contains 0.1 to 10 parts by weight of the (F) bifunctional or higher functional isocyanate compound and (G) the metal chelate compound with respect to 100 parts by weight of the total of the acrylic polymers of the copolymer. Containing 0.001 to 0.5 parts by weight of the cross-linking catalyst of (H) and 0.1 to 200 parts by weight of the (H) ketoenol tachivariant compound, and the above-mentioned (H) ketoenol remutable compound. / (G) The weight ratio (H) / (G) of the cross-linking catalyst of the metal chelate compound is 1 to 700, and further, as the (I) antistatic agent, the antistatic agent contained in the pressure-sensitive adhesive composition. And 0.05 to 5.0 parts by weight of the total of the antistatic agent copolymerized in the copolymer, and 0.01 to 1.0 part by weight of the (J) polyether-modified siloxane compound. , (K) It is preferable to contain 0.01 to 5 parts by weight of a tocopherol-based antioxidant as an antioxidant.

(A) Examples of the (meth) acrylic acid ester monomer having an alkyl group having C4 to C18 carbon atoms include butyl (meth) acrylate, isobutyl (meth) acrylate, pentyl (meth) acrylate, hexyl (meth) acrylate, and heptyl (meth). ) Acrylate, Octyl (meth) acrylate, Isooctyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, Nonyl (meth) acrylate, Isononyl (meth) acrylate, Decyl (meth) acrylate, Isodecyl (meth) acrylate, Undecyl (meth) ) Acrylate, dodecyl (meth) acrylate, tridecyl (meth) acrylate, tetradecyl (meth) acrylate, pentadecyl (meth) acrylate, hexadecyl (meth) acrylate, heptadecyl (meth) acrylate, octadecyl (meth) acrylate, myristyl (meth) acrylate. , Isomyristyl (meth) acrylate, cetyl (meth) acrylate, isosetyl (meth) acrylate, stearyl (meth) acrylate, isostearyl (meth) acrylate, and the like.
When the total amount of the acrylic polymers of the copolymer is 100 parts by weight, the (A) alkyl group contains 50 to 95 parts by weight of the (meth) acrylic acid ester monomer having C4 to C18 carbon atoms. Is preferable.

(B) Examples of the copolymerizable monomer containing a hydroxyl group include 8-hydroxyoctyl (meth) acrylate, 6-hydroxyhexyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, and 2-hydroxyethyl (meth) acrylate. Examples thereof include hydroxyalkyl (meth) acrylates such as, and hydroxyl group-containing (meth) acrylamides such as N-hydroxy (meth) acrylamide, N-hydroxymethyl (meth) acrylamide, and N-hydroxyethyl (meth) acrylamide.
8-Hydroxyoctyl (meth) acrylate, 6-hydroxyhexyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, 2-hydroxyethyl (meth) acrylate, N-hydroxy (meth) acrylamide, N-hydroxymethyl (meth) ) At least one selected from the compound group consisting of acrylamide and N-hydroxyethyl (meth) acrylamide is preferable.
When the total amount of the acrylic polymers of the copolymer is 100 parts by weight, it is preferable that the copolymerizable monomer containing the (B) hydroxyl group is contained in a ratio of 0.1 to 10 parts by weight.

(C) Copolymerizable monomers containing a carboxyl group are (meth) acrylic acid, carboxyethyl (meth) acrylate, carboxypentyl (meth) acrylate, 2- (meth) acryloyloxyethyl hexahydrophthalic acid, 2 -(Meta) acryloyloxypropyl hexahydrophthalic acid, 2- (meth) acryloyloxyethyl phthalic acid, 2- (meth) acryloyloxyethyl succinic acid, 2- (meth) acryloyloxyethyl maleic acid, carboxy It is preferably at least one selected from the compound group consisting of polycaprolactone mono (meth) acrylate and 2- (meth) acryloyloxyethyl tetrahydrophthalic acid.
When the total amount of the acrylic polymers of the copolymer is 100 parts by weight, the copolymerizable monomer containing the (C) carboxyl group may be contained in a proportion of 0.1 to 1.0 parts by weight. preferable. In the pressure-sensitive adhesive layer according to the present invention, the copolymerizable monomer containing (C) a carboxyl group in the pressure-sensitive adhesive composition has an acid value of 0.01 to 8.0 as described later. It is preferable to contain it within the range.

The (D) polyalkylene glycol mono (meth) acrylic acid ester monomer may be a compound in which one hydroxyl group is esterified as a (meth) acrylic acid ester among a plurality of hydroxyl groups of the polyalkylene glycol. Since the (meth) acrylic acid ester group becomes a polymerizable group, it can be copolymerized with the main polymer. The other hydroxyl group may be OH as it is, or may be an alkyl ether such as methyl ether or ethyl ether, a saturated carboxylic acid ester such as an acetate ester, or the like.
Examples of the alkylene group contained in the polyalkylene glycol include, but are not limited to, an ethylene group, a propylene group, and a butylene group. 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, polyethylene glycol-polypropylene glycol-polybutylene glycol, and the like. It may be a block copolymer or a random copolymer.
It is preferable that the polyalkylene glycol mono (meth) acrylic acid ester monomer (D) has an average number of repetitions of alkylene oxide constituting the polyalkylene glycol chain of 3 to 14. The "average number of repetitions of alkylene oxide" is the average number of repetitions of the alkylene oxide unit in the portion of the "polyalkylene glycol chain" contained in the molecular structure of the (D) polyalkylene glycol mono (meth) acrylic acid ester monomer. be.

The (D) polyalkylene glycol mono (meth) acrylic acid ester monomer was selected from polyalkylene glycol mono (meth) acrylate, methoxypolyalkylene glycol (meth) acrylate, and ethoxypolyalkylene glycol (meth) acrylate. It is preferably at least one kind.
More specifically, polyethylene glycol-mono (meth) acrylate, polypropylene glycol-mono (meth) acrylate, polybutylene glycol-mono (meth) acrylate, polyethylene glycol-polypropylene glycol-mono (meth) acrylate, polyethylene glycol-poly. Butylene glycol-mono (meth) acrylate, polypropylene glycol-polybutylene glycol-mono (meth) acrylate, polyethylene glycol-polypropylene glycol-polybutylene glycol-mono (meth) acrylate; methoxypolyethylene glycol- (meth) acrylate, methoxypolypropylene glycol -(Meta) acrylate, methoxypolybutylene glycol- (meth) acrylate, methoxy-polypropylene glycol-polypropylene glycol- (meth) acrylate, methoxy-polyethylene glycol-polybutylene glycol- (meth) acrylate, methoxy-polypropylene glycol-polybutylene Glycol- (meth) acrylate, methoxy-polypropylene glycol-polypropylene glycol-polybutylene glycol- (meth) acrylate; ethoxypolyethylene glycol- (meth) acrylate, ethoxypolypropylene glycol- (meth) acrylate, ethoxypolybutylene glycol- (meth) Acrylate, ethoxy-polypropylene glycol-polypropylene glycol- (meth) acrylate, ethoxy-polyethylene glycol-polybutylene glycol- (meth) acrylate, ethoxy-polypropylene glycol-polybutylene glycol- (meth) acrylate, ethoxy-polypropylene glycol-polypropylene glycol -Polybutylene glycol- (meth) acrylate and the like.
When the total amount of the acrylic polymers of the copolymer is 100 parts by weight, it is preferable that the (D) polyalkylene glycol mono (meth) acrylic acid ester monomer is contained in a ratio of 0 to 50 parts by weight. In the pressure-sensitive adhesive layer according to the present invention, the pressure-sensitive adhesive composition may not contain (D) a polyalkylene glycol mono (meth) acrylic acid ester monomer.

Among (E), examples of the (E-1) nitrogen-containing vinyl monomer 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, N-vinyl-2-pyrrolidone, N-vinylpyrrolidone, methylvinylpyrrolidone, N-vinylpyridine, N-vinylpiperidone, N-vinylpyrimidine, N-vinylpiperazine, N-vinylpyrazine, N-vinyl. Cyclic nitrogen vinyl compounds having an N-vinyl-substituted heterocyclic structure, such as pyrrol, N-vinylimidazole, N-vinyloxazole, N-vinylmorpholin, N-vinylcaprolacttam, N-vinyllauryllolactum; N-( Meta) acryloyl morpholine, N- (meth) acryloyl piperazine, N- (meth) acryloyl azylidine, N- (meth) acryloyl azetidin, N- (meth) acryloyl pyrrylidine, N- (meth) acryloyl piperidin, N- (meta). ) Cyclic nitrogen vinyl compounds having a heterocyclic structure of N- (meth) acryloyl substitution such as acryloyl azepan, N- (meth) acryloyl azocan; nitrogen atoms such as N-cyclohexylmaleimide and N-phenylmaleimide and Cyclic nitrogen vinyl compound having a heterocyclic structure having an ethylene-based unsaturated bond in the ring; (meth) acrylamide, N-methyl (meth) acrylamide, N-isopropyl (meth) acrylamide, N-t-butyl (meth) Unsubstituted or monoalkyl-substituted (meth) acrylamide such as acrylamide; N, N-dimethyl (meth) acrylamide, N, N-diethyl (meth) acrylamide, N, N-dipropylacrylamide, N, N-diisopropyl (meth). ) Acrylamide, N, N-dibutyl (meth) acrylamide, N-ethyl-N-methyl (meth) acrylamide, N-methyl-N-propyl (meth) acrylamide, N-methyl-N-isopropyl (meth) acrylamide, etc. Dialkyl-substituted (meth) acrylamide; N, N-dimethylaminomethyl (meth) acrylate, N, N-dimethylaminoethyl (meth) acrylate, N, N-dimethylaminopropyl (meth) acrylate, N, N-dimethylaminoisopropyl (Meta) acrylate, N, N-dimethylaminobutyl (meth) acrylate, N, N-diethylaminomethyl (meth) acrylate, N, N-diethylaminoethyl (meth) acrylate, N-ethyl-N-methylaminoethyl (meth) ) Acrylic, N-methyl-N-propylaminoethyl (meth) acrylate, N-methyl-N-isopropylaminoethyl (me D) Dialkylamino (meth) acrylates such as acrylate, N, N-dibutylaminoethyl (meth) acrylate, t-butylaminoethyl (meth) acrylate; N, N-dimethylaminopropyl (meth) acrylamide, N, N- Diethylaminopropyl (meth) acrylamide, N, N-dipropylaminopropyl (meth) acrylamide, N, N-diisopropylaminopropyl (meth) acrylamide, N-ethyl-N-methylaminopropyl (meth) acrylamide, N-methyl- N, N-dialkyl-substituted aminopropyl (meth) acrylamides such as N-propylaminopropyl (meth) acrylamide, N-methyl-N-isopropylaminopropyl (meth) acrylamide; N-vinylformamide, N-vinylacetamide, N- N-vinylcarboxylic acid amides such as vinyl-N-methylacetamide; N-methoxymethyl (meth) acrylamide, N-ethoxyethyl (meth) acrylamide, N-butoxymethyl (meth) acrylamide, diacetone acrylamide, N, N -(Meta) acrylamides such as methylenebis (meth) acrylamide; unsaturated carboxylic acid nitriles such as (meth) acrylonitrile; and the like.

(E-1) As the nitrogen-containing vinyl monomer, those containing no hydroxyl group are preferable, and those containing no hydroxyl group and a carboxyl group are more preferable. Examples of such a monomer include the monomers exemplified above, for example, an acrylic monomer containing an N, N-dialkyl substituted amino group or an N, N-dialkyl substituted amide group; N-vinyl-2-pyrrolidone, N-vinyl. N-vinyl-substituted lactams such as caprolactam and N-vinyl-2-piperidone; N- (meth) acryloyl-substituted cyclic amines such as N- (meth) acryloylmorpholine and N- (meth) acryloylpyrrolidine are preferred.

Among (E), examples of the (E-2) alkoxy group-containing alkyl (meth) acrylate monomer include 2-methoxyethyl (meth) acrylate, 2-ethoxyethyl (meth) acrylate, and 2-propoxyethyl (meth) acrylate. 2-Isopropoxyethyl (meth) acrylate, 2-butoxyethyl (meth) acrylate, 2-methoxypropyl (meth) acrylate, 2-ethoxypropyl (meth) acrylate, 2-propoxypropyl (meth) acrylate, 2-isopropoxy Propyl (meth) acrylate, 2-butoxypropyl (meth) acrylate, 3-methoxypropyl (meth) acrylate, 3-ethoxypropyl (meth) acrylate, 3-propoxypropyl (meth) acrylate, 3-isopropoxypropyl (meth) Acrylate, 3-butoxypropyl (meth) acrylate, 4-methoxybutyl (meth) acrylate, 4-ethoxybutyl (meth) acrylate, 4-propoxybutyl (meth) acrylate, 4-isopropoxybutyl (meth) acrylate, 4- Butoxybutyl (meth) acrylate and the like can be mentioned.
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.

When the total amount of the acrylic polymers of the copolymer is 100 parts by weight, the weight of the (E-1) hydroxyl group-free nitrogen-containing vinyl monomer or the (E-2) alkoxy group-containing alkyl (meth) acrylate monomer is 0 to 20 parts by weight. It is preferable that it is contained in a proportion of a portion. (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 of two or more. In the pressure-sensitive adhesive layer according to the present invention, the pressure-sensitive adhesive composition may not contain (E) a nitrogen-containing vinyl monomer containing no hydroxyl group or an alkoxy group-containing alkyl (meth) acrylate monomer.

(F) The bifunctional or higher functional isocyanate compound may be at least one or more selected from polyisocyanate compounds having at least two or more isocyanate (NCO) groups in one molecule. The polyisocyanate compound is classified into an aliphatic isocyanate, an aromatic isocyanate, an acyclic isocyanate, an alicyclic isocyanate and the like, but any of them may be used. 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), and xylylene diisocyanate (XDI). , Aromatic isocyanate compounds such as hydrogenated xylylene diisocyanate (H6XDI), dimethyldiphenylenedi isocyanate (TOID), and tolylene diisocyanate (TDI).
Examples of the trifunctional or higher functional isocyanate compound include a burette-modified form of a bifunctional isocyanate compound (a compound having two NCO groups in one molecule), an isocyanurate-modified form, and trivalent or higher valents such as trimethylolpropane (TMP) and glycerin. Examples thereof include an adduct form (polyol modified form) with a polyol (a compound having at least 3 or more OH groups in one molecule).
As the (F) bifunctional or higher functional isocyanate compound, it is also possible to use only the (F-1) trifunctional isocyanate compound or only the (F-2) bifunctional isocyanate compound. It is also possible to use the (F-1) trifunctional isocyanate compound and the (F-2) bifunctional isocyanate compound in combination.

Further, as the (F-1) trifunctional isocyanate compound used in the present invention, an isocyanurate form of a hexamethylene diisocyanate compound, an isocyanurate form of an isophorone diisocyanate compound, an adduct body of a hexamethylene diisocyanate compound, an adduct body of an isophorone diisocyanate compound, and the like. At least one selected from the (F-1-1) first aliphatic isocyanate compound group consisting of a burette of a hexamethylene diisocyanate compound and a burette of an isophorone diisocyanate compound, and a tolylene diisocyanate compound. Isocyanurate form, isocyanurate form of xylylene diisocyanate compound, isocyanurate form of hydrogenated xylylene diisocyanate compound, adduct form of tolylene diisocyanate compound, adduct form of xylylene diisocyanate compound, adduct form of hydrogenated xylylene diisocyanate compound. (F-1-2) It is preferable to contain at least one selected from the second aromatic isocyanate compound group. It is preferable to use (F-1-1) the first aliphatic isocyanate compound group and (F-1-2) the second aromatic isocyanate compound group in combination. In the present invention, as the (F-1) trifunctional isocyanate compound, at least one selected from the (F-1-1) first aliphatic isocyanate compound group and (F-1-2). ) By using at least one selected from the second aromatic isocyanate compound group in combination, the balance of adhesive force between the low-speed peeling region and the high-speed peeling region can be further improved.
Further, the (F-1) trifunctional isocyanate compound is at least one selected from the above-mentioned (F-1-1) first aliphatic isocyanate compound group, and the above-mentioned (F-1-2). ) Contains at least one selected from the second aromatic isocyanate compound group, and contains 0.5 to 5.0 parts by weight in total with respect to 100 parts by weight of the copolymer. Is preferable. Further, at least one selected from the (F-1-1) first aliphatic isocyanate compound group and (F-1-2) the second aromatic isocyanate compound group. The mixing ratio with at least one selected from the above is in the range of (F-1-1) :( F-1-2) in the range of 10%: 90% to 90%: 10% by weight. Is preferable.

Further, the (F-2) bifunctional isocyanate compound used in the present invention is preferably an acyclic aliphatic isocyanate compound, which is a compound produced by reacting a diisocyanate compound with a diol compound.
For example, a diisocyanate compound has a general formula "O = C = N-X-N = C = O" (where X is a divalent group), and a general formula "HO-Y-OH" (where Y is a divalent group). ), Examples of the compound produced by reacting the diisocyanate compound with the diol compound include the compound represented by the following general formula Z.

[General formula Z]
O = C = N-X- (NH-CO-O-YO-CO-NH-X) _n -N = C = O

Here, n is an integer of 0 or more. When n is 0, the general formula Z represents “O = C = N—X—N = C = O”. As the bifunctional acyclic aliphatic isocyanate compound, a compound having n of 0 in the general formula Z (a diisocyanate compound unreacted with a diol compound) may be contained, but a compound in which n is an integer of 1 or more is an essential component. It is preferable to include as. The bifunctional acyclic aliphatic isocyanate compound may be a mixture composed of a plurality of compounds having different n in the general formula Z.

The diisocyanate compound represented by the general formula “O = C = N—X—N = C = O” is an aliphatic diisocyanate. X is preferably an acyclic and aliphatic divalent group. The aliphatic diisocyanate is preferably one or more selected from the compound group consisting of tetramethylene diisocyanate, pentamethylene diisocyanate, hexamethylene diisocyanate, trimethylhexamethylene diisocyanate, and lysine diisocyanate.

The diol compound represented by the general formula "HO-Y-OH" is an aliphatic diol. Y is preferably an acyclic and aliphatic divalent group. Examples of the diol compound include 2-methyl-1,3-propanediol, 2,2-dimethyl-1,3-propanediol, 2-methyl-2-propyl-1,3-propanediol, and 2-ethyl-2. -From the compound group consisting of butyl-1,3-propanediol, 3-methyl-1,5-pentanediol, 2,2-dimethyl-1,3-propanediol monohydroxypivalate, polyethylene glycol, and polypropylene glycol. It is preferably composed of one or more selected species.

The weight ratio (F-1 / F-2) of the (F-1) trifunctional isocyanate compound to the (F-2) bifunctional isocyanate compound is preferably 1 to 90. The amount of the (F) bifunctional or higher isocyanate compound is preferably 0.1 to 10 parts by weight with respect to 100 parts by weight of the acrylic polymer.

(G) The cross-linking catalyst of the metal chelate compound may be any substance that functions as a catalyst for the reaction (cross-linking reaction) between the copolymer and the cross-linking agent when the polyisocyanate compound is used as the cross-linking agent. Examples thereof include amine compounds such as tertiary amines, metal chelate compounds, organic tin compounds, organic lead compounds, and organic metal compounds such as organic zinc compounds. In the present invention, a metal chelate compound is used as the cross-linking catalyst.

The metal chelate compound is a compound in which one or more polydentate ligands L are bonded to the central metal atom M. The metal chelate compound may or may not have one or more monodentate ligands X attached to the metal atom M. For example, when the general formula of a metal chelate compound having one metal atom M is expressed by M (L) _m (X) _n , m ≧ 1 and n ≧ 0. When m is 2 or more, m L may be the same ligand or may be 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, Sn and the like.
Examples of the polydentate ligand L include β-ketoesters such as methyl acetoacetate, ethyl acetoacetate, octyl acetoacetic acid, oleyl acetoacetic acid, lauryl acetoacetic acid, and stearyl acetoacetic acid, and acetylacetone (also known as 2,4-pentandione). Examples thereof include β-diketones such as 2,4-hexanedione and benzoylacetone. These are keto-enol tautomeric compounds and may be enol-deprotonated enolates (eg, acetylacetonate) in the polydentate ligand L.
Examples of the monodentate ligand X include halogen atoms such as chlorine atom and bromine atom, pentanoyl group, hexanoyl group, 2-ethylhexanoyl group, octanoyl group, nonanoyl group, decanoyl group, dodecanoyl group and octadecanoyl group. Examples thereof include an alkoxy group such as a 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-pentanedionato) iron (III), iron tris acetylacetonate, titaniumtris acetylacetonate, ruthenium trisacetylacetonate, zinc bisacetylacetonate, and aluminum tris. Acetylacetonate, Zirconite Tetrakis Acetylacetonate, Tris (2,4-Hexanedionate) Iron (III), Bis (2,4-HexaneDionato) Zinc, Tris (2,4-HexaneDionato) Titanium, Tris Examples thereof include (2,4-hexanezonato) aluminum and tetrakis (2,4-hexanezonato) zirconium.

Examples of the organic tin compound include dialkyl tin oxide, a fatty acid salt of dialkyl tin, and a fatty acid salt of first tin. Conventionally, dibutyltin compounds have been widely used, but in recent years, the problem of toxicity of organotin compounds has been pointed out, and in particular, tributyltin (TBT) contained in dibutyltin compounds is also a concern as an endocrine disruptor. From the viewpoint of safety, a long-chain alkyl tin compound such as a dioctyl tin compound is preferable. Specific examples of the organic tin compound include dioctyl tin oxide and dioctyl tin dilaurate. Sn compounds can be used provisionally, but in the future, in view of the trend that the use of safer substances is required, Al, Ti, Fe, etc., which are safer than Sn, etc. It is preferable to use a metal chelate compound.
The metal chelate compound in the pressure-sensitive adhesive composition according to the present invention is 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 (provided that they do not contain TBT). It is preferable that it contains more than a seed.
The cross-linking catalyst of the (G) metal chelate compound is preferably contained in an amount of 0.001 to 0.5 parts by weight with respect to 100 parts by weight of the copolymer.

(H) Ketoenol tetonic compounds include β-ketoesters such as methyl acetoacetate, ethyl acetoacetate, octyl acetoacetate, oleyl acetoacetic acid, lauryl acetoacetic acid, and stearyl acetoacetic acid, acetylacetone, and 2,4-hexanedione. , Β-diketone such as benzoylacetone. In a pressure-sensitive adhesive composition using a polyisocyanate compound as a cross-linking agent, these prevent excessive increase in viscosity and gelation of the pressure-sensitive adhesive composition after blending the cross-linking agent by blocking the isocyanate group contained in the cross-linking agent. , The pot life of the pressure-sensitive adhesive composition can be extended.
The keto-enol 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.

Since the (H) ketoenol tautomer compound has an effect of suppressing cross-linking as opposed to the cross-linking catalyst of the (G) metal chelate compound, the (H) keto-enol tautomer with respect to the cross-linking catalyst of the (G) metal chelate compound. It is preferable to appropriately set the ratio of the mutant compound. In order to prolong the pot life of the pressure-sensitive adhesive composition and improve the storage stability, the weight ratio (H) / (G) of the cross-linking catalyst of (H) keto-enol tautomer compound / (G) metal chelate compound is required. Is preferable. The value of (H) / (G) is preferably in the range of 1 to 700, more preferably 30 to 300, and most preferably 80 to 300.

(I) Examples of the antistatic agent include an antistatic agent contained in the pressure-sensitive adhesive composition and an antistatic agent copolymerized in the copolymer. It is preferable that the (I) antistatic agent is contained in an amount of 0.05 to 5.0 parts by weight with respect to 100 parts by weight of the copolymer.
The (I) antistatic agent is preferably (I-1) an ionic compound having a melting point of 25 to 50 ° C. and / or (I-2) an acryloyl group-containing ionic compound.
In the present invention, as (I) an antistatic agent, (I-1) an ionic compound having a melting point of 25 to 50 ° C. is added to the copolymer, and / or (I-2) an acryloyl group-containing ionic compound is added. Is copolymerized in the copolymer. Since these (I) antistatic agents have a low melting point and have a long-chain alkyl group, it is presumed that they have a high affinity with the acrylic copolymer.

(I-1) The ionic compound having a melting point of 25 to 50 ° C. is an ionic compound having a cation and an anion, and the cation is a pyridinium cation, an imidazolium cation, a pyrimidinium cation, or a pyrazonium cation. , Pyrrolidinium cations, ammonium cations and other nitrogen-containing onium cations, phosphonium cations, sulfonium cations and the like, and the anions are hexafluorinated phosphate (PF _6- ⁾ , thiocyanate (SCN- ⁾ , alkylbenzene sulfonates. Acid (RC ₆ H ₄ SO _3- ⁾ , perchlorate (ClO _4- ⁾ , borate tetrafluoride (BF _4- ⁾ , bis (fluorosulfonyl) imide salt (FSI), bis (trifluoromethanesulfonyl) ) Inorganic or organic anion compounds such as imide salt (TFSI), trifluoromethanesulfonate (TF) and the like. It is preferably 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 of the substituent, the number of substituents, and the like. The cation is preferably a quaternary nitrogen-containing onium cation, and is a quaternary pyridinium cation such as 1-alkylpyridinium (the carbon atom at the 2nd to 6th positions may have a substituent or may be unsubstituted), or 1, Examples thereof include a quaternary imidazolium cation such as 3-dialkyl imidazolium (the carbon atom at the 2, 4 and 5 positions may have a substituent or not substituted), a quaternary ammonium cation such as tetraalkylammonium and the like. ..
(I-1) The ionic compound having a melting point of 25 to 50 ° C. 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, and the cation is (meth) acryloyloxyalkyltrialkylammonium [R 3N ⁺ -C _n H _{2n -} OCOCQ. = CH ₂ , where Q = H or CH ₃ , R = alkyl] and other (meth) acryloyl group-containing cations, where the anions are hexafluorinated phosphate (PF _6- ⁾ , thiocyanate (SCN- ⁾ . ), Organic sulfonate (RSO _3- ⁾ , perchlorate (ClO _4- ⁾ , tetrafluoride borate (BF _4- ), ^{F -} containing imide salt (RF ₂ ^- N-), etc. Examples include compounds that are anions. ^Examples of the RF of the ^F _- containing imide salt (RF ^2N- ) include a perfluoroalkanesulfonyl group such as a trifluoromethanesulfonyl group and a pentafluoroethanesulfonyl group, and a fluorosulfonyl group. Examples of the F-containing imide salt include bis (fluorosulfonyl) imide salt [(FSO ₂ ) ₂ N- ^] , bis (trifluoromethanesulfonyl) imide salt [(CF ₃ SO ₂ ) ₂ N- ^] , and bis (pentafluoroethanesulfonyl). ) Bissulfonylimide salts such as imide salt [(C ₂ F ₅ SO ₂ ) ₂ N- ^] can be mentioned.
(I-2) The acryloyl group-containing ionic compound is preferably copolymerized in an amount of 0.1 to 5.0% by weight in the copolymer.

(I) Specific examples of the antistatic agent are not particularly limited, but (I-1) specific examples of the ionic compound having a melting point of 25 to 50 ° C. are 1-octylpyridinium hexafluorophosphorus. Acid, 1-nonylpyridinium hexafluorophosphate, 2-methyl-1-dodecylpyridinium hexafluorophosphate, 1-octylpyridinium dodecylbenzenesulfonate, 1-dodecylpyridinium thiocyanate, 1-dodecyl Examples thereof include pyridinium dodecylbenzene sulfonate, 4-methyl-1-octylpyridinium hexafluorophosphate, and a quaternary ammonium salt of trifluoromethanesulfonic acid. Further, as a specific example of the (I-2) acryloyl group-containing ionic compound, dimethylaminomethyl (meth) acrylate methyl hexafluorophosphate [(CH ₃ ) ₃ N ⁺ CH ₂ OCOCQ = CH ₂ · PF ₆ ^-However , Q = H or CH ₃ ], dimethylaminoethyl (meth) acrylate bis (trifluoromethanesulfonyl) imidemethyl salt [(CH ₃ ) ₃ N ⁺ (CH ₂ ) ₂ OCOCQ = CH ₂ · (CF ₃ SO ₂ ) ) ₂ N- ^, but Q = H or CH ₃ ], dimethylaminomethylmethacrylate bis (fluorosulfonyl) imidemethyl salt [(CH ₃ ) ₃ N ⁺ CH ₂ OCOCQ = CH ₂ · (FSO ₂ ) ₂ N- ^, but , Q = H or CH ₃ ] and the like.

The pressure-sensitive adhesive composition of the present invention contains (J) a polyether-modified siloxane compound. (J) The polyether-modified siloxane compound is a siloxane compound having a polyether group, and is a siloxane unit having a polyether group [-SiR ¹ (R)] in addition to the usual siloxane unit [-SiR ¹ ₂ -O-]. It has ² O (R ³ O) _n R ⁴ ) -O-]. Here, R ¹ is one or more kinds of alkyl groups or aryl groups, R ² and R ³ are one or more kinds of alkylene groups, and R ⁴ is one or more kinds of alkyl groups or acyl groups. Etc. (terminal group). Examples of the polyether group include a polyoxyalkylene group such as a polyoxyethylene group [(C ₂ H ₄ O) _n ] and a polyoxypropylene group [(C ₃ H ₆ O) _n ].
The (J) 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 (J) polyether-modified siloxane compound is contained with respect to 100 parts by weight of the copolymer. More preferably, it is 0.1 to 0.5 parts by weight.
The HLB is, for example, a hydrophilic lipophilic balance (hydrophilic lipophilic ratio) defined in JIS K3211 (surfactant term) and the like.
(J) The polyether-modified siloxane compound can be obtained, for example, by grafting an organic compound having an unsaturated bond and a polyoxyalkylene group on a polyorganosiloxane backbone having a silicon hydride group by a hydrosilylation reaction. can. Specifically, dimethylsiloxane / methyl (polyoxyethylene) siloxane copolymer, dimethylsiloxane / methyl (polyoxyethylene) siloxane / methyl (polyoxypropylene) siloxane copolymer, dimethylsiloxane / methyl (polyoxypropylene) Examples thereof include siloxane polymers.
By blending the (J) polyether-modified siloxane compound into the pressure-sensitive adhesive composition, the pressure-sensitive adhesive strength and rework performance of the pressure-sensitive adhesive can be improved. If the pressure-sensitive adhesive composition does not contain a polyether-modified siloxane compound, the cost will be lower.

The pressure-sensitive adhesive composition of the present invention contains (K) an antioxidant. Examples of the (K) antioxidant include hindered phenolic antioxidants, polyphenol compounds, tocopherol compounds and the like. Of these, tocopherol compounds are preferable. Tocopherol compounds are generally vitamin E and are also naturally occurring chemicals. For this reason, it has little adverse effect on the human body, is highly safe to handle, and is environmentally friendly. Further, since it is oil-soluble and liquid at room temperature, it is excellent in compatibility with the pressure-sensitive adhesive composition and precipitation resistance. (K) By blending a tocopherol compound as an 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.
Since the tocopherol-based compound used in the present invention is used by blending it in a pressure-sensitive adhesive composition (it is not metabolized like in the human body), the ferrule-like hydroxyl group of tocopherol is not changed to an ester or the like, and the ferrule property is obtained. A compound having a hydroxyl group is preferable. For example, tocopherols and tocotrienols can be mentioned. It is known that tocopherols and tocotrienols have a distinction between a natural compound (d-form), a non-natural compound (l-form), and a racemate (dl-form) which is a mixture thereof. ing. Natural compounds (d-form) and racemates (dl-form) are preferable because some of them are used as food additives and the like.
Specific tocopherol compounds include d-α-tocopherol, dl-α-tocopherol, d-β-tocopherol, dl-β-tocopherol, d-γ-tocopherol, dl-γ-tocopherol, and d-δ-tocopherol. , Dl-δ-tocotrienol, d-α-tocotrienol, dl-α-tocotrienol, d-β-tocotrienol, dl-β-tocotrienol, d-γ-tocotrienol, dl-γ-tocotrienol, d-δ-tocotrienol, dl At least one selected from the group of compounds consisting of -δ-tocotrienols can be mentioned. Two or more kinds of tocopherol compounds may be used in combination. As a food additive, what is called "mixed tocopherol" is a mixture containing d-α-tocopherol, d-β-tocopherol, d-γ-tocopherol and d-δ-tocotrienol as main components, and is referred to as "tocotrienol". What is called is a mixture containing d-α-tocotrienol, d-β-tocotrienol, d-γ-tocotrienol and d-δ-tocotrienol as main components.
The pressure-sensitive adhesive composition of the present invention preferably contains 0.01 to 5 parts by weight of the tocopherol compound with respect to 100 parts by weight of the copolymer.

Further, as other components, copolymerizable (meth) acrylic monomer containing alkylene oxide, (meth) acrylamide monomer, dialkyl-substituted acrylamide monomer, surfactant, curing catalyst, thermoplastic, filler, curing retarder, processing Known additives such as auxiliaries, antioxidants, and antioxidants can be appropriately added. These may be used alone or in combination of two or more.

The main agent copolymer used in the pressure-sensitive adhesive composition of the present invention is (A) as a group of monomers copolymerizable with at least one kind of (meth) acrylic acid ester monomer having an alkyl group having C4 to C18 carbon atoms (A). B) Containing a copolymerizable monomer containing a hydroxyl group, (C) a copolymerizable monomer containing a carboxyl group, (D) a polyalkylene glycol mono (meth) acrylic acid ester monomer, and (E) a hydroxyl group. It can be synthesized by copolymerizing a non-nitrogen-containing vinyl monomer or an alkoxy group-containing alkyl (meth) acrylate monomer and at least one selected from a group of copolymerizable monomers. The polymerization method of the copolymer is not particularly limited, and an appropriate polymerization method such as solution polymerization or emulsion polymerization can be used.
(I) When (I-2) an acryloyl group-containing ionic compound is used as the antistatic agent, the copolymer of the main agent used in the pressure-sensitive adhesive composition of the present invention has (A) an alkyl group having C4 carbon atoms. ~ C18 (meth) acrylic acid ester monomer, at least one copolymerizable monomer group, (B) a copolymerizable monomer containing a hydroxyl group, and (C) a copolymerizable monomer containing a carboxyl group. , (D) Polyalkylene glycol mono (meth) acrylic acid ester monomer, and (E) a group of copolymerizable monomers composed of a hydroxyl group-free nitrogen-containing vinyl monomer or an alkoxy group-containing alkyl (meth) acrylate monomer. It can be synthesized by copolymerizing at least one selected from the above with (I-2) an acryloyl group-containing ionic compound.
The pressure-sensitive adhesive composition of the present invention comprises the above-mentioned copolymer, (F) a cross-linking catalyst of a bifunctional or higher-functional isocyanate compound, (G) a metal chelate compound, and (H) a ketoenol homozygous compound, (I). It can be prepared by blending an antioxidant, (J) a polyether-modified siloxane compound, (K) an antioxidant, and an appropriate additive. When the (I-2) acryloyl group-containing ionic compound is polymerized in the copolymer of the main agent, the (I) antistatic agent may be further added to the copolymer, or may be added. It doesn't have to be.

The copolymer is preferably an acrylic polymer, and preferably contains 50 to 100% by weight of an acrylic monomer such as (meth) acrylic acid ester monomer, (meth) acrylic acid, and (meth) acrylamides.
The acid value of the acrylic polymer is preferably 0.01 to 8.0. As a result, the contamination property can be improved and the performance of preventing the generation of adhesive residue can be improved.
Here, the "acid value" is one of the indexes representing the acid content, and is represented by the number of mg of potassium hydroxide required to neutralize 1 g of the polymer containing a carboxyl group.

The pressure-sensitive adhesive layer formed by cross-linking 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 a high-speed peeling speed of 30 m / min. The adhesive strength is preferably 1.0 N / 25 mm or less. As a result, it is possible to obtain a performance in which the adhesive strength does not change much depending on the peeling speed, and it is possible to quickly peel even by high-speed peeling. Further, since it is reattached, even when the surface protective film is once peeled off, it does not require an excessive force and can be easily peeled off from the adherend.

It is preferable that the surface resistivity of the pressure-sensitive adhesive layer obtained by cross-linking the pressure-sensitive adhesive composition is 9.0 × 10 ⁺¹¹ Ω / □ or less, and the peeling band voltage is ± 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. If the surface resistivity is large, the ability to release the static electricity generated by charging during peeling is inferior. Therefore, by making the surface resistivity sufficiently small, the peeling that occurs due to the static electricity generated when the adherend peels off the adhesive layer. The band resistivity is reduced, and it is possible to suppress the influence on the electric control circuit of the adherend and the like.

The gel fraction of the pressure-sensitive adhesive layer (the pressure-sensitive adhesive after cross-linking) obtained by cross-linking the pressure-sensitive adhesive composition of the present invention is preferably 95 to 100%. Due to such a high gel content, the adhesive strength does not become excessive at a low peeling speed, the elution of unpolymerized monomers or oligomers from the copolymer is reduced, and the reworkability and high temperature / high humidity are achieved. Durability is improved and contamination of the adherend can be suppressed.

The pressure-sensitive adhesive film of the present invention is formed by forming a pressure-sensitive adhesive layer formed by cross-linking the pressure-sensitive adhesive composition of the present invention on one or both sides of a resin film. Further, the surface protective film of the present invention is a surface protective film formed by forming a pressure-sensitive adhesive layer formed by cross-linking 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 contains the above-mentioned components (A) to (K) in a well-balanced manner, it has excellent antistatic performance, and has a low peeling speed and a high peeling speed. It has an excellent balance of adhesive strength, and also has excellent durability and rework performance (no contamination transfer to the adherend after tracing the surface protective film with a ballpoint pen through the adhesive layer). Become. Therefore, it can be suitably used as a surface protective film for a polarizing plate.

As the base film of the pressure-sensitive adhesive layer and the release film (separator) for protecting the pressure-sensitive adhesive surface, a resin film such as a polyester film can be used.
On the base film, on the side opposite to the side where the adhesive layer of the resin film is formed, antifouling treatment with silicone-based or fluorine-based mold release agent or coating agent, silica fine particles, etc., application of antistatic agent, etc. Antistatic treatment such as kneading can be applied.
The release film is subjected to a mold release treatment with a silicone-based or fluorine-based mold release agent or the like on the surface of the pressure-sensitive adhesive layer that is combined with the adhesive surface.

Hereinafter, the present invention will be specifically described with reference to Examples.

<Manufacturing of acrylic copolymer>
[Example 1]
Nitrogen gas was introduced into a reaction apparatus equipped with a stirrer, a thermometer, a reflux condenser and a nitrogen introduction pipe, and the air in the reaction apparatus was replaced with nitrogen gas. After that, 100 parts by weight of 2-ethylhexyl acrylate, 3.0 parts by weight of 8-hydroxyoctyl acrylate, 0.4 parts by weight of acrylic acid, and polypropylene glycol monoacrylate (average number of repetitions of alkylene oxide constituting the polyalkylene glycol chain) were added to the reaction device. n = 12) 60 parts by weight of the solvent (ethyl acetate) was added together with 10 parts by weight. Then, 0.1 part by weight of azobisisobutyronitrile as a polymerization initiator was added dropwise over 2 hours and reacted at 65 ° C. for 6 hours to obtain an acrylic copolymer solution having a weight average molecular weight of 500,000 and used in Example 1. I got 1. A part of the acrylic copolymer was collected and used as a sample for measuring the acid value described later.
[Examples 2 to 6 and Comparative Examples 1 to 7]
The composition of the monomers is the same as that of the acrylic copolymer solution 1 used in Example 1 above, except that the compositions of the monomers are as described in (A) to (E) and (I-2) of Table 1. , Acrylic copolymer solutions used in Examples 2 to 6 and Comparative Examples 1 to 7 were obtained.

<Manufacturing of adhesive composition and surface protective film>
[Example 1]
1.5 parts by weight of 1-octylpyridinium hexafluorophosphate and 0.05 weight by weight of the polyether-modified siloxane compound (HLB = 7) with respect to the acrylic copolymer solution 1 of Example 1 produced as described above. Parts, 8.5 parts by weight of acetylacetone and 0.1 part by weight of α-tocopherol were added and stirred, and then 2.0 parts by weight of coronate HX (isocyanurate compound of hexamethylene diisocyanate compound) and 0.1 parts of titanium trisacetylacetonate were added. Parts by weight were added and stirred and mixed to obtain the pressure-sensitive adhesive composition of Example 1. This pressure-sensitive adhesive composition is applied onto a release film made of a polyethylene terephthalate (PET) film coated with a silicone resin, and then dried at 90 ° C. to remove the solvent, and the pressure-sensitive adhesive layer has a thickness of 25 μm. I got a sheet.
After that, the adhesive sheet is transferred to the surface opposite to the antistatic and antifouling treated polyethylene terephthalate (PET) film on one surface, and "antistatic and antifouling treated". A surface protective film of Example 1 having a laminated structure of "PET film / adhesive layer / release film (PET film coated with silicone resin)" was obtained.
[Examples 2 to 6 and Comparative Examples 1 to 7]
Examples 2 to 6 and Comparative Example 1 are the same as the surface protective film of Example 1 above, except that the compositions of the additives are as described in Table 2 (F) to (K), respectively. A surface protective film of ~ 7 was obtained.

Tables 1 and 2 divide the integrated table showing the compounding ratio of each component into two, and in each case, the numerical value of the weight part obtained by assuming that the total of the group (A) is 100 parts by weight is enclosed in parentheses. Indicated by. The value of the ratio of (H) / (G) is shown in Table 3. The compound names of the abbreviations of the respective components used in Tables 1 and 2 are shown in Tables 4 and 5. Coronate (registered trademark) HX, HL and L are trade names of Nippon Polyurethane Industry Co., Ltd., and Takenate (registered trademark) D-140N, D-127N, D-110N and D-120N are Mitsui Chemicals shares. It is a product name of the company, and Death Module (registered trademark) N3400 is a product name of Sumika Bayer Urethane Co., Ltd.
In Table 1, among the (I) antistatic agents, the (I-2) acryloyl group-containing ionic compound copolymerized in the copolymer is different from the (I) antistatic agent added after the polymerization. Described in the column of.

<Synthesis of bifunctional isocyanate compound>
The bifunctional isocyanate compounds of Synthesis Examples 1 to 3 were synthesized by the following methods. As shown in Tables 6 and 7, the diisocyanate and the diol compound were mixed at a molar ratio of NCO / OH = 16 and reacted at 120 ° C. for 3 hours, and then under reduced pressure using a thin film evaporator. The unreacted diisocyanate was removed to obtain the desired bifunctional isocyanate compound.

<Test method and evaluation>
The surface protective films of Examples 1 to 6 and Comparative Examples 1 to 7 were aged at 23 ° C. and 50% RH for 7 days, and then the release film (silicone resin coated PET film) was peeled off to adhere. The exposed agent layer was used as a sample for measuring the surface resistance.
Further, the surface protective film on which the pressure-sensitive adhesive layer is exposed is attached to the surface of the polarizing plate attached to the liquid crystal cell via the pressure-sensitive adhesive layer, left for 1 day, and then left at 50 ° C., 5 atm for 20 minutes. A sample that had been autoclaved and left at room temperature for another 12 hours was used as a sample for measuring adhesive strength, peeling band voltage, reworkability, and durability.

<Adhesive strength>
The measurement sample obtained above (a 25 mm wide surface protective film bonded to the surface of the polarizing plate) was subjected to a low speed peeling speed (0.3 m / min) and a high speed in the 180 ° direction using a tensile tester. The peeling strength was taken as the adhesive strength after peeling at the peeling speed (30 m / min).

<Surface resistivity>
After aging, before bonding to the polarizing plate, the release film (PET film coated with silicone resin) is peeled off to expose the adhesive layer, and the resistance meter Hiresta UP-HT450 (manufactured by Mitsubishi Chemical Analytec) is used. The surface resistance of the pressure-sensitive adhesive layer was measured.

<Peeling band voltage>
High-precision electrostatic sensors SK-035 and SK-200 (stocks) can be used to measure the voltage (band voltage) generated by charging the polarizing plate when the measurement sample obtained above is peeled 180 ° at a tensile speed of 30 m / min. It was measured using (manufactured by the company Keyence), and the maximum value of the measured value was taken as the peeling band voltage.

<Reworkability>
After tracing the surface protective film of the measurement sample obtained above with a ball pen (load 500 g, 3 reciprocations), the surface protective film is peeled off from the polarizing plate, the surface of the polarizing plate is observed, and the polarizing plate is contaminated. Confirmed that there was no migration. The evaluation target criteria are "○" when there is no contamination transfer on the polarizing plate, "△" when contamination transfer is confirmed at least in part along the trajectory traced with the ballpoint pen, and along the trajectory traced with the ballpoint pen. When the transfer of contamination was confirmed and the detachment of the adhesive was confirmed from the surface of the adhesive, it was evaluated as "x".

<Pot life>
The viscosity η ₀ (initial viscosity) of the pressure-sensitive adhesive composition immediately after blending the additives (F) to (K) was measured, and the pressure-sensitive adhesive composition was left in a sealed state at 23 ° C. for 8 hours for adhesion. The viscosity η ₁ (viscosity after 8 hours) of the agent composition was measured. As an index of pot life, the value of η ₁ when η ₀ was 1.0, that is, the ratio of η ₁ / η ₀ was obtained. The evaluation target criteria are "○" when the viscosity after 8 hours is less than 1.25 times the initial viscosity, "△" when it is 1.25 times or more and less than 1.50 times, 1.50 times or more or The case where the gel was formed after being left for 8 hours was evaluated as "x".

<Durability>
The measurement sample obtained above was left in an atmosphere of 60 ° C. and 90% RH for 250 hours, then taken out to room temperature, left for another 12 hours, and then the adhesive strength was measured and clearly compared with the initial adhesive strength. It was confirmed that there was no significant increase. The evaluation target criteria were evaluated as "◯" when the adhesive strength after the test was 1.5 times or less of the initial adhesive strength, and "x" when the adhesive strength exceeded 1.5 times.

Table 8 shows the evaluation results. The surface resistivity is expressed by a method in which "m × 10 ^{+ n} " is set to "mE + n" (where m is an arbitrary real number and n is a positive integer).

The surface protective films of Examples 1 to 6 have an adhesive strength of 0.05 to 0.1 N / 25 mm at a low peeling speed of 0.3 m / min and an adhesive strength of 1 at a high peeling speed of 30 m / min. It is 0.0 N / 25 mm or less, the surface resistance is 9.0 × 10 ^{+ 11} Ω / □ or less, the peeling band voltage is ± 0 to 0.5 kV, and it is placed on the surface protective film via the adhesive layer. After tracing with a ball pen, there was no transfer of contamination to the adherend, the pot life was long, and the durability was excellent when left in an atmosphere of 60 ° C. and 90% RH for 250 hours.
That is, it has antistatic performance, has an excellent balance of adhesive strength at a low peeling speed and a high peeling speed, has a long pot life, and has excellent durability and reworkability.
Further, according to the surface protective films of Examples 1 to 6, since the pressure-sensitive adhesive composition does not contain the organic tin compound, the safety is high.

The surface protective film of Comparative Example 1 does not contain (F) a bifunctional or higher functional isocyanate compound as a cross-linking agent, and has an adhesive force at a low peeling speed of 0.3 m / min and a high peeling speed of 30 m / min. Was too large, the peeling band voltage was high, and the reworkability and durability were inferior.
In the surface protective film of Comparative Example 2, the ratio of the (H) ketoenol tautomer compound to the cross-linking catalyst of the (G) metal chelate compound was small, and the HLB value of the (J) polyether-modified siloxane compound was excessive. (K) Probably because it does not contain an antioxidant, the peeling zone voltage is high, the pot life is short, and the durability is inferior.
The surface protective film of Comparative Example 3 uses a cross-linking catalyst of an organotin compound instead of the cross-linking catalyst of the (G) metal chelate compound, and does not contain (K) an antioxidant, so that the pot life becomes too short. Since the cross-linking proceeded before the coating, the coating could not be performed.
The surface protective film of Comparative Example 4 did not contain (G) a cross-linking catalyst of a metal chelate compound and (H) a ketoenol tautomer compound, and did not contain (J) a polyether-modified siloxane compound (K). ) Probably because it does not contain an antioxidant, the adhesive strength at a high peeling speed of 30 m / min is too large, the pot life is short, and the durability is inferior.
As described above, the surface protective films of Comparative Examples 1 to 4 have antistatic performance, have an excellent balance of adhesive strength at a low peeling speed and a high peeling speed, and have a long pot life, durability and durability. It was not possible to meet all the required performances, which are excellent in reworkability, at the same time.
Further, in the surface protective films of Comparative Examples 5 to 7, since the cross-linking catalyst is not a metal chelate compound but an organic tin compound, safety may be regarded as a problem in the future.

Claims (3)

(A) At least one kind of (meth) acrylic acid ester monomer having an alkyl group having C4 to C18, a copolymerizable monomer containing (B) a hydroxyl group as a copolymerizable monomer group, and (C) carboxyl. A group-containing copolymerizable monomer, (D) a polyalkylene glycol mono (meth) acrylic acid ester monomer, and (E) a hydroxyl group-free nitrogen-containing vinyl monomer or an alkoxy group-containing alkyl (meth) acrylate monomer. It is composed of an acrylic polymer of a copolymer having an acid value of 0.01 to 8.0, which comprises at least one selected from the copolymerizable monomer group consisting of (F), and further has (F) bifunctionality or higher. An isocyanate compound, a cross-linking catalyst of (G) a metal chelate compound, (H) a ketoenol copolymer compound, (I) an antioxidant, (J) a polyether-modified siloxane compound, and (K) an antioxidant. And, containing,
The copolymerizable monomer containing the (B) hydroxyl group is 8-hydroxyoctyl (meth) acrylate, 6-hydroxyhexyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, or 2-hydroxyethyl (meth) acrylate. , N-Hydroxy (meth) acrylamide, N-hydroxymethyl (meth) acrylamide, N-hydroxyethyl (meth) acrylamide, at least one selected from the group of compounds.
The copolymerizable monomer containing the (C) carboxyl group is (meth) acrylic acid, carboxyethyl (meth) acrylate, carboxypentyl (meth) acrylate, 2- (meth) acryloyloxyethyl hexahydrophthalic acid, 2- (Meta) acryloyloxypropyl hexahydrophthalic acid, 2- (meth) acryloyloxyethyl phthalic acid, 2- (meth) acryloyloxyethyl succinic acid, 2- (meth) acryloyloxyethyl maleic acid, At least one selected from the group of compounds consisting of carboxypolycaprolactone mono (meth) acrylate and 2- (meth) acryloyloxyethyl tetrahydrophthalic acid.
The (D) polyalkylene glycol mono (meth) acrylic acid ester monomer has an average number of repetitions of alkylene oxides constituting the polyalkylene glycol chain of 3 to 14, and polyalkylene glycol mono (meth) acrylate and methoxypolyalkylene glycol. At least one selected from (meth) acrylate and ethoxypolyalkylene glycol (meth) acrylate.
A pressure-sensitive adhesive layer having a surface resistivity of 9.0 × 10 ⁺¹¹ Ω / □ or less and a peeling band voltage of ± 0 to 0.5 kV. A pressure-sensitive adhesive film, wherein the pressure-sensitive adhesive layer according to claim 1 is formed on one side or both sides of a resin film. A surface protective film comprising the pressure-sensitive adhesive layer according to claim 1 formed on one side or both sides of a resin film.