TWI648363B - Adhesive composition and surface protection film - Google Patents

Abstract

The present invention provides an adhesive composition having antistatic performance, excellent balance of adhesion at low peeling speed and high peeling speed, and long storage life, and excellent durability and reworkability. The adhesive composition includes: (A) at least one of (C) to C18 alkyl (meth) acrylate monomers having an alkyl group and (B) a hydroxyl group-containing copolymerizable monomer as a copolymerizable monomer group; 100 parts by weight of a copolymer of monomers; (C) 0.1 to 10 parts by weight of a difunctional or higher isocyanate compound; (D) 0.001 to 0.5 parts by weight of a metal chelate crosslinking catalyst; (E) keto-enol intervariability 0.1 to 200 parts by weight of the structure compound; 0.05 to 5 parts by weight of the ionic compound having a melting point of 25 to 50 ° C as the (F) antistatic agent, and a ratio of (E) / (D) to 70 parts by weight .

Description

Adhesive composition and surface protective film

The invention relates to an adhesive composition and a surface protective film. More specifically, the present invention relates to a surface protective film for a polarizing plate having antistatic properties, excellent balance of adhesion at low peeling speed and high peeling speed, long storage life, and excellent durability and reworkability. Use an adhesive composition and a surface protective film.

From the viewpoint of excellent transparency, an optical adhesive is preferably a copolymer obtained by copolymerizing an alkyl (meth) acrylate as a main component and an acrylic monomer having a hydroxyl group, a carboxyl group, or the like as a functional group. Composition of acrylic adhesive. In addition, an adhesive that appropriately adjusts various physical properties such as adhesion is required. In particular, in order to be suitable for a manufacturing process in a factory, adhesives for surface protective films, etc., are required to have excellent balance of adhesion at low peeling speed and high peeling speed suitable for bonding by an automatic bonding device. . Furthermore, in addition to the balance of the adhesive force, an adhesive having a long shelf life and excellent durability, reworkability, and antistatic properties is required.

For various physical properties of this adhesive, it is possible to use isocyanate-based crosslinking agents, epoxy-based crosslinking agents, etc., which react with functional groups such as hydroxyl and carboxyl groups contained in acrylic-based adhesives composed of copolymers. To carry out the crosslinking reaction, so as to adjust the adhesion and cohesion.

Conventionally, as a crosslinking agent of an acrylic adhesive, an isocyanate-based crosslinking agent has generally been used. In addition, in a 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.

Generally speaking, from the viewpoint of the excellent reaction speed of the cross-linking reaction, an organic tin compound, that is, dibutyltin dilaurate, is used as a catalyst for the cross-linking reaction, but the dibutyltin compound is currently being avoided due to its harmful toxicity. use.

Therefore, there is a need for a cross-linking catalyst that can be used in combination with an isocyanate-based cross-linking agent, can replace a dibutyltin compound, is inexpensive, and has an excellent reaction speed in the cross-linking reaction, but it is difficult to develop.

In view of the foregoing, Patent Document 1 discloses the following: As a cross-linking catalyst that can be used in combination with an isocyanate-based cross-linking agent, an iron chelate is preferred among metal chelates; and because of tris (acetamidineacetone) coordination Iron is particularly preferred because of its excellent catalytic activity.

However, the acrylic pressure-sensitive adhesive composition containing a cross-linking catalyst slowly undergoes a cross-linking reaction even during storage at normal temperature. Therefore, in the industrial production of adhesives, a crosslinking catalyst and a reaction inhibitor are usually used in combination in order to stop the crosslinking reaction from the time when the raw materials of the adhesive composition are blended to the start of the crosslinking reaction.

Regarding the combined use of the cross-linking catalyst and the reaction inhibitor, Patent Document 2 discloses a method for producing polyurethane, which uses a mixture containing at least one metal acetoacetone and acetoacetone and the aforementioned metal acetamidine A reactive polyurethane mixture of a catalyst system having a weight ratio of acetone to the aforementioned acetoacetone of 2: 1.

For the adhesive composition described in Patent Document 1, the amount of the metal compound (crosslinking catalyst) added to the copolymer containing a hydroxyl group and a carboxyl group as a monomer unit (meth) acrylate is proposed. , But does not describe the amount of cross-linking inhibitor added. Further, in Patent Document 1, as a method of suppressing a viscosity increase rate after a crosslinking agent is added to an adhesive composition, a method using a reaction inhibitor, a method of adding a solvent for suppressing viscosity increase, and the like are used. A method of a cross-linking agent that blocks (blocks) a functional group, such as a block isocyanate, is not specifically described.

In addition, Patent Document 2 discloses a method for producing polyurethane, in which the catalyst system used contains a metal acetoacetone catalyst such as iron, copper, or the like, which has a very high activity at low temperatures, and does not cause early curing, and has excellent properties. The stability and good catalytic activity of metal acetoacetone and acetoacetone.

However, in the method described in Patent Document 2, the weight ratio of metal acetoacetone to acetoacetone is set to 2: 1. However, even when the compounding ratio is used in the production process of the acrylic adhesive, it cannot be achieved. The crosslinking reaction is temporarily stopped.

Prior art literature

Patent literature

Patent Document 1: Japanese Patent Application Laid-Open No. 2011-001440

Patent Document 2: Japanese Patent Application Laid-Open No. 2008-285681

Problems to be solved by the invention

The present invention has been made in view of the above circumstances, and an object thereof is to provide an antistatic property without using an organotin compound, excellent balance of adhesion at low peeling speed and high peeling speed, and long storage life. An adhesive composition for a surface protective film of a polarizing plate which is also excellent in durability, reworkability, and a surface protective film.

Technical means to solve problems

In order to solve the above problems, the present invention provides an adhesive composition.

The adhesive composition includes (A) at least one of (C) to C18 alkyl (meth) acrylate monomers having an alkyl group and (B) a hydroxyl-containing copolymerizable monomer as a copolymerizable monomer group. 100 parts by weight of a copolymer; (C) 0.1 to 10 parts by weight of a difunctional or higher isocyanate compound; (D) 0.001 to 0.5 parts by weight of a metal chelate crosslinking catalyst; (E) keto-enol tautomerism 0.1 to 200 parts by weight of a bulk compound; 0.05 to 5 parts by weight of an ionic compound having a melting point of 25 to 50 ° C as an antistatic agent (F), and a ratio of (E) / (D) to 70 parts by weight.

In addition, it is preferable that the (B) hydroxyl-containing copolymerizable monomer is selected from the group consisting of 8-hydroxyoctyl (meth) acrylate, 6-hydroxyhexyl (meth) acrylate, and 4-hydroxybutyl (meth) acrylate. Esters, 2-hydroxyethyl (meth) acrylate, N-hydroxy (meth) acrylamide, N-hydroxymethyl (meth) acrylamide, and N-hydroxyethyl (meth) acrylamide At least one or more compounds in the composition group.

Moreover, as said (C) difunctional or more isocyanate compound, it is preferable that it is an acyclic aliphatic isocyanate compound as a difunctional isocyanate compound, and is a compound produced by making a diisocyanate compound and a diol compound react. The diisocyanate compound is an aliphatic diisocyanate, and is preferably selected from the group consisting of tetramethylene diisocyanate, pentamethylene diisocyanate, hexamethylene diisocyanate, trimethylhexamethylene diisocyanate, and ionamine. One of the compound group consisting of acid diisocyanate. The diol compound is preferably selected from 2-methyl-1,3-propanediol, 2,2-dimethyl-1,3-propanediol, and 2-methyl-2-propyl-1. 1,3-propanediol, 2-ethyl-2-butyl-1,3-propanediol, 3-methyl-1,5-pentanediol, 2,2-dimethyl-1,3-propanediol monohydroxy new One of the compound group consisting of valerate, polyethylene glycol, and polypropylene glycol.

In addition, as the (C) difunctional or higher isocyanate compound, an isocyanurate selected from the group consisting of a hexamethylene diisocyanate compound and an isophorone diisocyanate compound as the trifunctional isocyanate compound is preferable. Acid ester, adduct of hexamethylene diisocyanate compound, adduct of isophorone diisocyanate compound, biuret of hexamethylene diisocyanate compound, biuret of isophorone diisocyanate compound , Isocyanurate of toluene diisocyanate compound, isocyanurate of xylylene diisocyanate compound, isocyanurate of hydrogenated xylylene diisocyanate compound, adduct of toluene diisocyanate compound, At least one or more of a compound group consisting of an adduct of a xylylene diisocyanate compound and an adduct of a hydrogenated xylylene diisocyanate compound.

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

The (F) antistatic agent preferably contains 0.05 to 5.0 parts by weight of an ionic compound having a melting point of 25 to 50 ° C based on 100 parts by weight of the copolymer, and / or an amount of copolymerization in the copolymer. It is an ionic compound containing 0.1 to 5.0% by weight and containing an acrylfluorene group.

The aforementioned copolymer preferably includes at least one or more of a carboxyl group-containing monomer, a hydroxyl group-containing nitrogen-containing vinyl monomer, and a polyalkylene glycol mono (meth) acrylate monomer as another copolymerizable monomer group. , And / or as additives include polyether siloxane compounds and other general antioxidants.

In addition, it is preferable that the adhesive force of the adhesive layer formed by crosslinking the adhesive composition at a low peeling speed of 0.3 m / min is 0.05 to 0.1 N / 25 mm, and the adhesive force at a high peeling speed of 30 m / min is 1.0N / 25mm or less.

In addition, the surface resistivity of the adhesive layer obtained by crosslinking the adhesive composition is preferably 9.0 × 10 ⁺¹¹ Ω / □ or less, and the peeling static voltage is ± 0 to 0.5 kV.

In addition, the present invention provides an adhesive film formed by forming an adhesive layer on one or both sides of a resin film, and the adhesive layer is formed by crosslinking the aforementioned adhesive composition.

In addition, the present invention provides a surface protection film formed by forming an adhesive layer on one side of a resin film, the adhesive layer being formed by cross-linking the aforementioned adhesive composition, wherein the adhesive is adhered with a ball pen After the agent layer was painted on the surface protection film, the contamination was not transferred to the adherend.

In addition, the surface protection film of the present invention can be used as a surface protection of a polarizing plate.

In the surface protection film of the present invention, it is preferable that antistatic and antifouling treatments are performed on the surface of the resin film opposite to the side on which the adhesive layer is formed.

efficacy

Based on the present invention, all the properties required for the adhesive layer of the surface protection film that cannot be solved in the prior art can be satisfied without using an organic tin compound, and excellent antistatic properties can be obtained, which can prevent adhesive residues. The occurrence of the phenomenon. Specifically, not only the excellent antistatic performance can be maintained, but also the addition amount of the antistatic agent can be reduced, and the performance of preventing the adhesive from remaining can be improved.

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

The adhesive composition of the present invention includes: (A) at least one of (C) to C18 alkyl (meth) acrylate monomers having an alkyl group and (B) a hydroxyl group-containing polymer having a copolymerizable monomer group; 100 parts by weight of a comonomer copolymer; (C) 0.1 to 10 parts by weight of a difunctional or higher isocyanate compound; (D) 0.001 to 0.5 parts by weight of a metal chelate crosslinking catalyst; (E) a keto-enol interaction 0.1 to 200 parts by weight of a isomer compound; and 0.05 to 5 parts by weight of an ionic compound having a melting point of 25 to 50 ° C as the (F) antistatic agent, and a ratio of (E) / (D) to 70 parts by weight ~ 700.

The aforementioned copolymer may include at least one of a carboxyl group-containing monomer, a hydroxyl group-containing nitrogen-containing vinyl monomer, and a polyalkylene glycol mono (meth) acrylate monomer as another copolymerizable monomer group. the above.

The (F) antistatic agent may contain 0.05 to 5.0 parts by weight of the ionic compound having a melting point of 25 to 50 ° C based on 100 parts by weight of the copolymer, and / or the copolymerization amount in the copolymer may be 0.1. -5.0% by weight and an ionic compound containing acryl fluorenyl group.

The adhesive composition of the present invention may include, as an additive, a polyether siloxane compound and other general antioxidants.

Examples of the (A) alkyl (meth) acrylate monomer having C4 to C18 carbon atoms include butyl (meth) acrylate, isobutyl (meth) acrylate, and (meth) acrylic acid Amyl ester, hexyl (meth) acrylate, heptyl (meth) acrylate, octyl (meth) acrylate, isooctyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, (formyl) (Nonyl) acrylate, isononyl (meth) acrylate, decyl (meth) acrylate, isodecyl (meth) acrylate, undecyl (meth) acrylate, twelve (meth) acrylate Alkyl ester, tridecyl (meth) acrylate, tetradecyl (meth) acrylate, pentadecyl (meth) acrylate, cetyl (meth) acrylate, (formyl) Base) heptadecyl acrylate, octadecyl (meth) acrylate, myristyl (meth) acrylate, isotetradecyl (meth) acrylate, cetyl (meth) acrylate, Isohexadecyl (meth) acrylate, stearyl (meth) acrylate, and (meth) propylene Isostearyl acrylate.

The content of the (A) alkyl (meth) acrylate monomer having C4 to C18 in the (A) alkyl group is preferably 50 to 98 parts by weight based on 100 parts by weight of the copolymer.

Examples of the (B) hydroxyl-containing copolymerizable monomer include 8-hydroxyoctyl (meth) acrylate, 6-hydroxyhexyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, and ( Hydroxyalkyl (meth) acrylates such as 2-hydroxyethyl methacrylate; N-hydroxy (meth) acrylamide, N-hydroxymethyl (meth) acrylamide, and N-hydroxyethyl Hydroxyl-containing (meth) acrylamide and the like such as (meth) acrylamide.

Preferably, the above-mentioned hydroxyl-containing copolymerizable monomer is selected from the group consisting of 8-hydroxyoctyl (meth) acrylate, 6-hydroxyhexyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, and (methyl) ) 2-hydroxyethyl acrylate, N-hydroxy (meth) acrylamide, N-hydroxymethyl (meth) acrylamide and N-hydroxyethyl (meth) acrylamide At least one more.

The content of the (B) hydroxyl-containing copolymerizable monomer is preferably 0.1 to 10 parts by weight based on 100 parts by weight of the copolymer.

For the aforementioned copolymers, it can also be used as other copolymerizable monomer groups, including carboxyl-containing monomers, hydroxyl-free nitrogen-containing vinyl monomers, and polyalkylene glycol mono (meth) acrylate monomers. At least one or more of them.

Preferably, the carboxyl group-containing monomer is selected from the group consisting of (meth) acrylic acid, carboxyethyl (meth) acrylate, carboxypentyl (meth) acrylate, and 2- (meth) acryloxyethylhexahydro Phthalic acid, 2- (meth) acryloxypropylhexahydrophthalic acid, 2- (meth) acryloxyethyl phthalate, 2- (meth) acryloxy Ethyl ethyl succinic acid, 2- (meth) acryloxyethylmaleic acid, carboxy polycaprolactone mono (meth) acrylate, and 2- (meth) acryloxyethyl tetrahydro-o At least one or more of the compound group consisting of phthalic acid.

When the aforementioned copolymer includes a carboxyl group-containing monomer as another copolymerizable monomer group, the content of the carboxyl group-containing monomer is preferably 0.1 to 1.0 part by weight relative to 100 parts by weight of the aforementioned copolymer. The copolymer may not contain the carboxyl group-containing monomer.

As said polyalkylene glycol mono (meth) acrylate monomer, what is necessary is just a compound in which one of the several hydroxyl groups which a polyalkylene glycol has is esterified into a (meth) acrylate. . Since the (meth) acrylate group is a polymerizable group, it can be copolymerized with a copolymer of a main agent. The other hydroxyl group may be in the state of OH, may be an alkyl ether such as methyl ether and diethyl ether, or may be a saturated carboxylic acid ester such as acetate.

Examples of the alkylene group included in the polyalkylene glycol include, but are not limited to, vinyl, propenyl, and butenyl. 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 polyalkylene glycol copolymer include polyethylene glycol-polypropylene glycol, polyethylene glycol-polybutylene glycol, polypropylene glycol-polybutylene glycol, and polyethylene glycol-polypropylene glycol-polybutylene glycol. The copolymer may be a block copolymer or a random copolymer.

It is preferable that the average repeating number of the alkylene oxide which comprises a polyalkylene glycol chain in the said polyalkylene glycol mono (meth) acrylate monomer is 3-14. The "average repeat number of alkylene oxide" refers to the alkylene oxide in the "polyalkylene glycol chain" part contained in the molecular structure of the polyalkylene glycol mono (meth) acrylate monomer. The average number of unit repeats.

The polyalkylene glycol mono (meth) acrylate monomer is preferably selected from the group consisting of polyalkylene glycol mono (meth) acrylate and methoxy polyalkylene glycol (meth) acrylic acid. Ester and at least one of ethoxy polyalkylene glycol (meth) acrylate.

More specific examples include polyethylene glycol-mono (meth) acrylate, polypropylene glycol-mono (meth) acrylate, polybutylene glycol-mono (meth) acrylate, and polyethylene glycol. -Polypropylene glycol-mono (meth) acrylate, polyethylene glycol-polybutylene glycol-mono (meth) acrylate, polypropylene glycol-polybutylene glycol-mono (meth) acrylate, polyethylene glycol -Polypropylene glycol-polybutylene glycol-mono (meth) acrylate; methoxy polyethylene glycol- (meth) acrylate, methoxy polypropylene glycol- (meth) acrylate, methoxy polybutylene Glycol- (meth) acrylate, methoxy-polyethylene glycol-polypropylene glycol- (meth) acrylate, methoxy-polyethylene glycol-polybutylene glycol- (meth) acrylate, Methoxy-polypropylene glycol-polybutylene glycol- (meth) acrylate, methoxy-polyethylene glycol-polypropylene glycol-polybutylene glycol- (meth) acrylate; ethoxy polyethylene glycol -(Meth) acrylate, ethoxy polypropylene glycol- (meth) acrylate, ethoxy polybutylene glycol- (meth) acrylate, ethoxy-polyethylene glycol-polypropylene glycol- (methyl Based) acrylate, ethoxy-polyethylene glycol-polybutylene glycol- (meth) acrylate, ethoxy-polypropylene glycol-polybutylene glycol- (meth) acrylate, ethoxy-poly Ethylene glycol-polypropylene glycol-polybutylene glycol- (meth) acrylate.

The content of the polyalkylene glycol mono (meth) acrylate monomer is preferably 0 to 50 parts by weight based on 100 parts by weight of the copolymer. The copolymer may not include the polyalkylene glycol mono (meth) acrylate monomer.

Examples of the vinyl monomer containing no hydroxyl group and containing nitrogen include a vinyl monomer containing a amide bond, a vinyl monomer containing an amine group, and a vinyl monomer having a nitrogen-containing heterocyclic structure. . More specifically, N-vinyl-2-pyrrolidone, N-vinylpyrrolidone, methylvinylpyrrolidone, N-vinylpyridine, N-vinylpyridone, N-vinylpyrimidine, N-vinylpyrazine, N-vinylpyrazine, N-vinylpyrrole, N-vinylimidazole, N-vinyloxazole, N-vinylmorpholine, N-vinylcaprolactam, and N -Cyclic nitrogen vinyl compounds having N-vinyl substituted heterocyclic structures such as vinyl dodecylamine; N- (meth) acrylfluorenylmorpholine, N- (meth) acrylfluorenylfluorene Azine, N- (meth) propenylaziridine, N- (meth) propenylaziridine, N- (meth) propenylpyrrolidine, N- (meth) propenylpyrrolyl N- (meth) acrylfluorenyl azacycloheptane, N- (meth) acrylfluorenyl azacycloheptane, and N- (meth) acrylfluorenyl octane substituted heterocyclic structures Cyclic nitrogen vinyl compounds; N-cyclohexyl maleimide, N-phenyl maleimide, and other cyclic nitrogen vinyls having a heterocyclic structure containing a nitrogen atom and a vinyl unsaturated bond in the ring Based compound; ( Unsubstituted or monoalkyl groups such as acrylamide, N-methyl (meth) acrylamide, N-isopropyl (meth) acrylamide, and N-tert-butyl (meth) acrylamide Substituted (meth) 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 -Dialkyl-substituted (meth) acrylamide such as methyl-N-propyl (meth) acrylamide and N-methyl-N-isopropyl (meth) acrylamide; N, N- Dimethylaminomethyl (meth) acrylate, N, N-dimethylaminoethyl (meth) acrylate, N, N-dimethylaminopropyl (meth) acrylate, N, N-dimethylaminoisopropyl (meth) acrylate, N, N-dimethylaminobutyl (meth) acrylate, N, N-diethylaminomethyl (methyl Group) acrylate, N, N-diethylaminoethyl (meth) acrylate, N-ethyl-N-methylaminoethyl (meth) acrylate, N-methyl-N -Propylaminoethyl (meth) acrylate, N-methyl-N-isopropylaminoethyl (meth) acrylate, N, N-dibutylaminoethyl (methyl) Dialkylamine (meth) acrylates such as acrylate and tert-butylaminoethyl (meth) acrylate; N, N-dimethylaminopropyl (meth) acrylamidoamine, N, N-diethylaminopropyl (meth) acrylamide, N, N-dipropylaminopropyl (meth) acrylamide, N, N-diisopropylaminopropyl (methyl Group) acrylamide, N-ethyl-N-methylaminopropyl (meth) acrylamide, N-methyl-N-propylaminopropyl (meth) acrylamide, and N- N, N-dialkyl substituted aminopropyl (meth) acrylamide, such as methyl-N-isopropylaminopropyl (meth) acrylamide; N-vinylformamide, N -N-vinylcarboxylic acid amines such as vinylacetamide and N-vinyl-N-methylacetamide; N-methoxymethyl (meth) acrylamidine, N-ethoxy Ethyl (meth) acrylamide, N-butoxymethyl (meth) acrylamide, diacetone acrylamide, and N, N-methylenebis (meth) acryl Amine (meth) acrylamide-based; (meth) acrylonitrile, unsaturated carboxylic acid nitriles and the like.

The content of the vinyl monomer containing no hydroxyl group and containing nitrogen is preferably 0 to 20 parts by weight based on 100 parts by weight of the copolymer. The said copolymer may not contain the said vinyl monomer which does not contain the said hydroxyl group, and contains nitrogen.

The (C) difunctional or higher isocyanate compound may be at least one kind or two or more kinds selected from polyisocyanate compounds having at least two isocyanate (NCO) groups in one molecule. Polyisocyanate compounds include classifications of aliphatic isocyanates, aromatic isocyanates, acyclic isocyanates, and alicyclic isocyanates, and the present invention may be any of them. 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), xylylene diisocyanate (XDI), hydrogenated xylylene diisocyanate (H6XDI), dimethyldiphenylene diisocyanate (TODI), and toluene diisocyanate (TDI ) And other aromatic isocyanate compounds.

Examples of the trifunctional or higher isocyanate compound include biuret-modified or isocyanurate-modified bifunctional isocyanate compounds (compounds having two NCO groups in one molecule), and trimethylol. Adducts (polyol modified products) of trivalent or higher polyhydric alcohols (compounds having at least three or more OH groups in one molecule) such as propane (TMP) or glycerol.

As the (C) difunctional or higher isocyanate compound, only (C-1) a trifunctional isocyanate compound or only (C-2) a difunctional isocyanate compound may be used. In addition, (C-1) a trifunctional isocyanate compound and (C-2) a difunctional isocyanate compound may be used in combination.

The (C-1) trifunctional isocyanate compound used in the present invention preferably includes at least one or more selected from the group of (C-1-1) first aliphatic isocyanate compounds and is selected from (C-1- 2) At least one or more of the second aromatic isocyanate compound group, wherein the (C-1-1) first aliphatic isocyanate compound group is an isocyanurate composed of a hexamethylene diisocyanate compound Isocyanurate of isophorone diisocyanate compound, adduct of hexamethylene diisocyanate compound, adduct of isophorone diisocyanate compound, biuret of hexamethylene diisocyanate compound And the biuret of isophorone diisocyanate compound; the (C-1-2) second aromatic isocyanate compound group is composed of toluene diisocyanate compound isocyanurate, xylylene dimethionate Isocyanurate of isocyanate compound, isocyanurate of hydrogenated xylylene diisocyanate compound, addition product of toluene diisocyanate compound, addition product of xylylene diisocyanate compound Adducts of hydrogenated xylylene diisocyanate compound composed. The (C-1-1) first aliphatic isocyanate compound group and the (C-1-2) second aromatic isocyanate compound group are preferably used in combination. In the present invention, as the (C-1) trifunctional isocyanate compound, at least one or more selected from the (C-1-1) first aliphatic isocyanate compound group is used in combination and selected from (C-1-2) ) At least one or more of the second aromatic isocyanate compound group can further improve the balance of the adhesive force in the low-speed peeling region and the high-speed peeling region.

In addition, it is preferable that the (C-1) trifunctional isocyanate compound includes at least one selected from the aforementioned (C-1-1) first aliphatic isocyanate compound group and the aforementioned (C-1-2) second At least one or more of the aromatic isocyanate compound groups, and the total content of the (C) trifunctional or higher isocyanate compound is 0.5 to 5.0 parts by weight based on 100 parts by weight of the copolymer. In addition, as a mixture of at least one or more selected from the (C-1-1) first aliphatic isocyanate compound group and at least one or more selected from the (C-1-2) second aromatic isocyanate compound group The ratio is preferably calculated in a weight ratio such that (C-1-1): (C-1-2) is within a range of 10%: 90% to 90%: 10%.

The (C-2) difunctional isocyanate compound used in the present invention is preferably an acyclic aliphatic isocyanate compound, and a compound formed by a reaction between a diisocyanate compound and a diol compound.

For example, when the diisocyanate compound is represented by the general formula "O = C = NXN = C = O" (where X is a divalent group), and the general formula "HO-Y-OH" (where Y is a divalent group) When the group) represents a diol compound, examples of the compound produced by the reaction between the diisocyanate compound and the diol compound include compounds represented by the following general formula Z.

[Formula 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 general formula Z is expressed as "O = C = N-X-N = C = O". The difunctional acyclic aliphatic isocyanate compound may include a compound in which n is 0 (a diisocyanate compound unreacted with respect to a diol compound) in the general formula Z, and a compound containing n as an integer of 1 or more as an essential component is preferable. The bifunctional acyclic aliphatic isocyanate compound may be a mixture of a plurality of compounds in which n is different in the general formula Z.

The diisocyanate compound represented by the general formula "O = C = N-X-N = C = O" is an aliphatic diisocyanate. Preferably, X is an acyclic aliphatic divalent group. The aliphatic diisocyanate is preferably selected from the group consisting of tetramethylene diisocyanate, pentamethylene diisocyanate, hexamethylene diisocyanate, trimethylhexamethylene diisocyanate, and lysine diisocyanate. One or two or more compounds in the composition group.

The diol compound represented by the general formula "HO-Y-OH" is an aliphatic diol. Preferably, Y is an acyclic aliphatic divalent group. The diol compound is preferably selected from 2-methyl-1,3-propanediol, 2,2-dimethyl-1,3-propanediol, 2-methyl-2-propyl-1, 3-propanediol, 2-ethyl-2-butyl-1,3-propanediol, 3-methyl-1,5-pentanediol, 2,2-dimethyl-1,3-propanediol monohydroxyneopent One or two or more of the compound group consisting of an acid ester, polyethylene glycol, and polypropylene glycol.

The weight ratio (C-1 / C-2) of the (C-1) trifunctional isocyanate compound to the (C-2) difunctional isocyanate compound is preferably 1 to 90. It is preferable that it is 0.1-10 weight part with respect to 100 weight part of said copolymers, and the said (C) bifunctional or more isocyanate compound.

In the case where a polyisocyanate compound is used as the crosslinking agent, the crosslinking catalyst for the (D) metal chelate compound may be any substance that functions as a catalyst and functions in the reaction (crosslinking reaction) of the copolymer and the crosslinking agent. Examples include amine compounds such as tertiary amines, metal chelates, organic tin compounds, organic lead compounds, organic zinc compounds, and the like. In the present invention, a metal chelate is used as the crosslinking catalyst.

The metal chelate is a compound in which one or more polydentate ligands L are bonded to a central metal atom M. The metal chelate may or may not have one or more monodentate ligands X bonded to the metal atom M. For example, when the general formula of a metal chelate compound having one metal atom M is represented by M (L) _m (X) _n , m _≧ 1 and _{n ≧ 0} . When m is 2 or more, m Ls may be the same ligand or different ligands. When n is 2 or more, n X may be the same ligand or different ligands.

Examples of the metal atom M include iron (Fe), nickel (Ni), manganese (Mn), chromium (Cr), vanadium (V), titanium (Ti), ruthenium (Ru), zinc (Zn), and aluminum ( Al), zirconium (Zr), tin (Sn), and the like.

Examples of the multidentate ligand L include methyl ethyl acetate, ethyl ethyl acetate, ethyl ethyl acetate, oleyl ethyl acetate, lauryl ethyl acetate, and stearyl ethyl acetate. β-keto esters; β-diketones such as acetoacetone (alias: 2,4-pentanedione), 2,4-hexanedione, and benzophenone acetone. They are keto-enol tautomers, and in the multidentate ligand L may also be enolates (eg, acetamidine acetonate) formed by deprotonation of the enol.

Examples of the monodentate ligand X include a halogen atom such as a chlorine atom and a bromine atom; pentamyl, hexyl, 2-ethylhexyl, octyl, nonyl, decyl, sulfanyl, and An alkoxy group such as stearyl, and the like; methoxy, ethoxy, n-propoxy, isopropoxy, and alkoxy such as butoxy.

Specific examples of the metal chelate include tris (2,4-pentanedionato) iron (III), triacetin iron acetone, and triethyl Titanium acetone, ruthenium triacetate acetone, zinc diacetonate acetone, aluminum triacetonate acetone, zirconium tetraacetonate acetone, tris (2,4-hexadione) iron (III), bis (2,4-hexane Diketone) zinc, tris (2,4-hexadione) titanium, tris (2,4-hexadione) aluminum, and tetra (2,4-hexadione) zirconium.

Examples of the organotin compounds include dialkyltin oxides, fatty acid salts of dialkyltin, and fatty acid salts of stannous acids. In the past, dibutyltin compounds have been used in most cases, but in recent years, the toxicity of organic tin compounds has been pointed out. In particular, tributyltin (TBT) contained in dibutyltin compounds is also a cause of concern. From the viewpoint of safety, a long-chain alkyltin compound such as a dioctyltin compound is preferred. Specific examples of the organotin compound include dioctyltin oxide and dioctyltin dilaurate. Although Sn compounds can also be used temporarily, in view of the tendency to use more safe substances in the future, it is preferable to use metal chelates such as Al, Ti, Fe, etc., which are safer than Sn.

The metal chelate compound in the adhesive composition of the present invention preferably contains at least one or more members selected from the group consisting of an aluminum chelate compound, a titanium chelate compound, and an iron chelate compound.

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

Examples of (E) keto-enol tautomers include methyl ethyl acetate, ethyl ethyl acetate, octyl ethyl acetate, oleyl ethyl acetate, lauryl ethyl acetate, and ethyl ethyl acetate Β-ketoesters such as stearyl acetate; β-diketones such as acetoacetone, 2,4-hexanedione, and benzophenone acetone. In an adhesive composition using a polyisocyanate compound as a cross-linking agent, by blocking the isocyanate group of the cross-linking agent, they can suppress the excessive increase in the viscosity of the adhesive composition or gelation after the cross-linking agent is mixed. This phenomenon can extend the shelf life of the adhesive composition.

The content of the (E) keto-enol tautomer compound is preferably 0.1 to 200 parts by weight based on 100 parts by weight of the copolymer.

In contrast to (D) a metal chelate cross-linking catalyst, (E) a keto-enol tautomer has an effect of inhibiting cross-linking. Therefore, it is preferable to appropriately set (E) a keto-enol tautomer. Ratio of the compound to the crosslinking catalyst of (D) metal chelate. In order to extend the shelf life of the adhesive composition and improve storage stability, the weight ratio (E) / (D) of the crosslinking catalyst of (E) keto-enol tautomer compound / (D) metal chelate compound is preferred ) Is a high value. The value of (E) / (D) is preferably in the range of 70 to 700, more preferably 70 to 300, and most preferably 80 to 300.

Examples of the (F) antistatic agent include an antistatic agent contained in the adhesive composition and an antistatic agent copolymerized in the copolymer. The content of the antistatic agent (F) is preferably 0.05 to 5.0 parts by weight based on 100 parts by weight of the copolymer.

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

In the present invention, as the (F) antistatic agent, (F-1) an ionic compound having a melting point of 25 to 50 ° C. is added to the copolymer, and / or (F-2) an ion containing acryl fluorenyl group is added. Sexual compounds are copolymerized in the copolymer. It is estimated that these (F) antistatic agents have a low melting point and long-chain alkyl groups, and therefore have high affinity with acrylic copolymers.

(F-1) The ionic compound having a melting point of 25 to 50 ° C is an ionic compound having a cation and an anion, and examples thereof include a pyridinium cation, an imidazolium cation, a pyrimidinium cation, a pyrazolium cation, Nitrogen cations such as pyrrolium cations and ammonium cations, or sulfonium cations, sulfonium cations, etc., the anions are hexafluorophosphate (PF ₆ ^— ), thiocyanate (SCN ^— ), alkylbenzene sulfonate (RC ₆ H ₄ SO ₃ ^— ), perchlorate (ClO ₄ ^— ), tetrafluoroborate (BF ₄ ^— ), bis (fluorosulfonyl) imide (FSI), bis (trifluoromethanesulfonyl) 醯Compounds of inorganic or organic anions such as imine (TFSI) and triflate (TF). It is preferably solid at normal temperature (for example, 25 ° C), and a compound having 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 substituents, and the like. Preferred cations are quaternary azinium cations, and examples include quaternary pyridinium cations such as 1-alkylpyridinium (carbon atoms at the 2 to 6 position may or may not have a substituent), 1,3-bis Quaternary imidazolium cations such as alkylimidazolium (carbon atoms at the 2, 4, and 5 positions may or may not have a substituent), and quaternary ammonium cations such as tetraalkylammonium.

The content of the ionic compound having a melting point of 25 to 50 ° C. (F-1) is preferably 0.05 to 5 parts by weight based on 100 parts by weight of the copolymer.

(F-2) The ionic compound containing acrylfluorenyl group is an ionic compound having a cation and an anion. Examples of the ionic compound include (meth) acryloxyalkyltrialkylammonium (R ₃ N ⁺ _{-C n H 2n -OCOCQ = CH 2} , where, Q = H or CH _3, R = alkyl) or the like containing the cationic (meth) Bingxi Xi group; hexafluorophosphate anion (PF ₆ ^-), Thiocyanate (SCN ^— ), Organic Sulfonate (RSO ₃ ^— ), Perchlorate (ClO ₄ ^— ), Tetrafluoroborate (BF ₄ ^— ), Fimide (R ^F ₂ N ^— ) And other inorganic or organic anionic compounds. (PEI) containing a root of F (R ^F ₂ N ^-) of R & lt ^F, include trifluoromethanesulfonic acyl, sulfo pentafluoroethyl acyl group such as a perfluoroalkyl sulfonic acyl, sulfo-fluoro-acyl. Examples of the fluorenimide group containing F include bis (fluorosulfonyl) sulfonium imine [(FSO ₂ ) ₂ N ^— ], bis (trifluoromethanesulfonyl) sulfonium imine [[CF ₃ SO ₂ ) ₂ N ^— ], bis (pentafluoroethanesulfonyl) fluorenimide [(C ₂ F ₅ SO ₂ ) ₂ N ^— ], and the like.

The copolymerization amount of the (F-2) propylene fluorene-containing ionic compound in the copolymer is preferably 0.1 to 5.0% by weight.

Specific examples of the (F) antistatic agent are not particularly limited, but specific examples of the (F-1) ionic compound having a melting point of 25 to 50 ° C include 1-octylpyridinium hexafluorophosphate, 1-nonylpyridinium hexafluorophosphate, 2-methyl-1-dodecylpyridinium hexafluorophosphate, 1-octylpyridinium dodecylbenzenesulfonate, 1-dodecyl Pyridinium thiocyanate, 1-dodecylpyridinium dodecylbenzenesulfonate, 4-methyl-1-octylpyridinium hexafluorophosphate, and quaternary ammonium salt of trifluoromethanesulfonic acid, etc. . In addition, as a specific example of the ionic compound containing acrylfluorenyl group (F-2), dimethylaminomethyl (meth) acrylate hexafluorophosphate methyl salt [(CH ₃ ) ₃ N ⁺ CH ₂ OCOCQ = CH ₂ • PF ₆ ^— , where Q = H or CH ₃ ], dimethylaminoethyl (meth) acrylate bis (trifluoromethanesulfonyl) fluorene imine methyl salt [ ^{_{(CH 3) 3 N + (}} CH 2) 2 OCOCQ = CH 2 • (CF 3 SO 2) 2 N -, where, Q = H or CH _3], methacrylic acid dimethylamino ester bis (fluoromethyl Sulfo) phosphonium imine methyl salt [(CH ₃ ) ₃ N ⁺ CH ₂ OCOCQ = CH ₂ • (FSO ₂ ) ₂ N ^— , where Q = H or CH ₃ ] and the like.

The adhesive composition of the present invention may contain a polyether siloxane compound and other general antioxidants as additives.

The aforementioned polyether-modified silicone compound is a silicone compound having a polyether group, and has a silicone unit containing a polyether group in addition to a normal silicone unit (-SiR ¹ ₂ -O-). (-SiR ¹ (R ² O (R ³ O) _n R ⁴ ) -O-). Here, R ¹ represents one or two or more alkyl or aryl groups, R ² and R ³ represent one or two or more alkylene groups, and R ⁴ represents one or two or more alkyl groups, fluorenyl groups, and the like ( Terminal group). Examples of the polyether group include polyoxyalkylene groups such as a polyoxyethylene group ((C ₂ H ₄ O) _n ) and a polyoxypropylene group ((C ₃ H ₆ O) _n ).

The polyether-modified silicone compound is preferably a polyether-modified silicone compound having an HLB value of 7 to 15. The content of the polyether-modified silicone compound is preferably 0.01 to 1.0 part by weight, and more preferably 0.1 to 0.5 part by weight, based on 100 parts by weight of the copolymer.

HLB refers to a predetermined hydrophilic-lipophilic balance (a ratio of hydrophilicity to lipophilicity) specified in JIS K3211 (surfactant term).

The aforementioned polyether-modified siloxane compound can be obtained, for example, by a method of grafting an organic compound having an unsaturated bond and a polyoxyalkylene group to a polyorganosiloxane having a silane group by a hydrosilylation reaction. Obtained from the main chain. Specific examples thereof include a dimethylsiloxane-methyl (polyoxyethylene) siloxane copolymer, and a dimethylsiloxane-methyl (polyoxyethylene) siloxane-methyl (poly (ethylene oxide)) (Propylene oxide) silicone copolymer and dimethylsilane-methyl (polyoxypropylene) silicone copolymer.

By blending the polyether-modified silicone compound with the adhesive composition, the adhesive force and reworkability of the adhesive can be improved. When the adhesive composition does not contain a polyether-modified silicone compound, the cost can be made lower.

Examples of the antioxidant include hindered phenol-based antioxidants, polyphenol compounds, and tocopherol-based compounds. Among them, a tocopherol compound is preferred. Tocopherols are usually vitamin E and are derived from natural chemicals. Therefore, it has less adverse effects on the human body, has high safety in use, and is conducive to protecting the environment. In addition, since it is oil-soluble and liquid at normal temperature, it has excellent compatibility with the adhesive composition and excellent precipitation resistance. By blending the tocopherol compound as the above-mentioned antioxidant, the storage stability of the adhesive is improved, and therefore the shelf life of the adhesive composition to which the curing agent has been added is increased.

As the tocopherol compound used in the present invention, a compound containing a phenolic hydroxyl group without being converted into an ester or the like from the viewpoint of being used in an adhesive composition (which does not undergo metabolism in the human body) is used. Examples include tocopherol and tocotrienol. It is known that tocopherols and tocotrienols are distinguished by natural compounds (d-body), non-natural compounds (l-body), racemic bodies (dl-body) of their equivalent mixtures, and the like. Natural compounds (d-forms) and racemic forms (dl-forms) are substances which can also be used as food additives and the like, and are therefore preferred.

Specific examples of tocopherols include compounds selected from the group consisting of 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- at least one of the compound group consisting of β-tocotrienol, d-γ-tocotrienol, dl-γ-tocotrienol, d-δ-tocotrienol, and dl-δ-tocotrienol One. Two or more tocopherol compounds may be used in combination. As a food additive, a substance called "mixed tocopherol" is mainly composed of d-α-tocopherol, d-β-tocopherol, d-γ-tocopherol, and d-δ-tocopherol. A mixture of ingredients; substances known as "tocotrienols" are d-α-tocotrienols, d-β-tocotrienols, d-γ-tocotrienols and d-δ-tocopherols Trienol is a mixture of main ingredients.

When the adhesive composition of the present invention contains a tocopherol compound, the content of the tocopherol compound is preferably 0.01 to 5 parts by weight based on 100 parts by weight of the copolymer.

In addition, as other components, a copolymerizable (meth) acrylic acid monomer containing an alkylene oxide, a (meth) acrylamide monomer, a dialkyl-substituted acrylamide monomer, Known additives such as surfactants, curing catalysts, plasticizers, fillers, curing inhibitors, processing aids, anti-aging agents, and antioxidants. These may be used alone or in combination of two or more.

As the copolymer of the main agent used in the adhesive composition of the present invention, at least one of (A) alkyl (meth) acrylate monomers having C4 to C18 carbon atoms can be used as a copolymerizable monomer. (B) a hydroxyl group-containing copolymerizable monomer is copolymerized and synthesized. 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.

When the (F-2) propylene fluorene group-containing ionic compound is used as the (F) antistatic agent, the copolymer of the main agent used in the adhesive composition of the present invention can be obtained by changing the carbon atom of the (A) alkyl group. At least one of (C) to C18 (meth) acrylate monomers, (B) a hydroxyl-containing copolymerizable monomer as a copolymerizable monomer group, and (F-2) an propylene fluorenyl group-containing ion Synthetic compounds are copolymerized.

In addition, for the aforementioned copolymer, the other copolymerizable monomer group may include a carboxyl group-containing monomer, a hydroxyl group-containing nitrogen-containing vinyl monomer, and a polyalkylene glycol mono (meth) acrylate monomer. At least one or more of them.

The adhesive composition of the present invention can be obtained by compounding (C) a difunctional or higher isocyanate compound, (D) a metal chelate cross-linking catalyst, and (E) a keto-enol tautomer compound in the copolymer. (F-1) an ionic compound having a melting point of 25 to 50 ° C as an antistatic agent (F-1), and an appropriate optional additive. In addition, if (F-2) an acrylofluorenyl group-containing ionic compound is polymerized in the main component copolymer, the copolymer may be further added with a (F-1) melting point as an (F) antistatic agent. The ionic compound having a melting point of 25 to 50 ° C may not be added as the (F) antistatic agent (F-1).

The copolymer is preferably an acrylic polymer, and preferably contains 50 to 100% by weight of a (meth) acrylic acid ester monomer or an acrylic monomer such as (meth) acrylic acid or (meth) acrylamide.

The acid value of the copolymer is preferably 0.01 to 8.0. Thereby, it is possible to improve the contamination property and the performance of preventing the occurrence of an adhesive residue phenomenon.

Here, the "acid value" is one of the indicators showing the acid content, and is expressed in mg of potassium hydroxide required to neutralize 1 g of a polymer containing a carboxyl group.

The adhesive layer formed by cross-linking the adhesive composition preferably has an adhesive force at a low peeling speed of 0.3 m / min of 0.05 to 0.1 N / 25 mm, and an adhesive force at a high peeling speed of 30 m / min is 1.0. N / 25mm or less. As a result, a small change in the adhesive force with the peeling speed can be obtained, and the peeling can be performed quickly even in the case of high-speed peeling. In addition, even when the surface protection film is temporarily peeled for re-adhesion, an excessive force is not required, and it is easy to peel from the adherend.

The surface resistivity of the adhesive layer obtained by crosslinking the adhesive composition is preferably 9.0 × 10 ⁺¹¹ Ω / □ or less, and the peeling static voltage is ± 0 to 0.5 kV. In addition, 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 performance of discharging the static electricity generated by the charging at the time of peeling is poor. Therefore, by making the surface resistivity sufficiently small, it is possible to reduce the static electricity generated when the adhesive layer is peeled from the adherend. The peeling static voltage can suppress the influence on the electrical control circuit and the like of the adherend.

The gel fraction of the adhesive layer (crosslinked adhesive) obtained by crosslinking the adhesive composition of the present invention is preferably 95 to 100%. Because the gel fraction is so high, the adhesive force does not become too large at low peel speeds, reducing the phenomenon of dissolution of unpolymerized monomers or oligomers from the copolymer, which can improve reworkability, high temperature / high Durability under wet conditions and suppresses contamination by adherends.

The adhesive film of the present invention is formed by forming an adhesive layer on one or both sides of a resin film, and the adhesive layer is formed by crosslinking the adhesive composition of the present invention. In addition, the surface protective film of the present invention is formed by forming an adhesive layer on one side of a resin film, and the adhesive layer is formed by crosslinking the adhesive composition of the present invention. In the adhesive composition of the present invention, since each of the components (A) to (F) is blended in a good balance, it has excellent antistatic performance, and has an adhesive force at a low peeling speed and a high peeling speed. It is excellent in balance, durability, and reworkability (after drawing on a surface protective film with an adhesive pen through an adhesive layer, it does not transfer contamination to the adherend). Therefore, a surface protective film as a polarizing plate can be preferably used.

Among the adhesive film and the surface protective film of the present invention, a polyester film or the like can be used as a base material of a resin film or a release film (separator) that protects an adhesive layer.

In addition, the resin film may be formed on the surface of the resin film opposite to the side where the adhesive layer is formed by using a silicone-based, fluorine-based release agent or coating agent, or silica particles. The antifouling treatment may be an antistatic treatment by applying or mixing an antistatic agent.

In addition, the release film is subjected to a release treatment with a silicone-based, fluorine-based release agent, or the like on the surface to be bonded to the adhesive surface of the adhesive layer.

Examples

Hereinafter, the present invention will be specifically described based on examples.

<Production of acrylic copolymer>

[Example 1]

Nitrogen was introduced into a reaction device equipped with a stirrer, a thermometer, a reflux condenser, and a nitrogen introduction tube, thereby replacing the air in the reaction device with nitrogen. Then, 100 parts by weight of 2-ethylhexyl acrylate and 3.5 parts by weight of 8-hydroxyoctyl acrylate were added to the reaction apparatus. Then, after 2 hours, 0.1 part by weight of azobisisobutyronitrile as a polymerization initiator was added dropwise and reacted at 65 ° C. for 6 hours to obtain acrylic acid for Example 1 having a weight average molecular weight of 500,000. Copolymer Solution 1. A part of the acrylic copolymer was taken and used as an acid value measurement sample described later.

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

Except that the composition of each monomer was adjusted as shown in (A), (B), (I), and (F-2) in Table 1, it was the same as the acrylic copolymer solution 1 used in Example 1 described above. The acrylic copolymer solution used in Examples 2 to 6 and Comparative Examples 1 to 3 was obtained. 【Table 1】

<Manufacture of an adhesive composition and a surface protection film>

[Example 1]

To the acrylic copolymer solution 1 of Example 1 manufactured as described above, 1.5 parts by weight of 1-octylpyridinium hexafluorophosphate and 4.0 parts by weight of acetamidine and acetone were added, and then 1.5 parts by weight of hexamethylene was added. Diisocyanate compound isocyanurate (trade name Coronate HX) and 0.05 parts by weight of tris (2,4-pentanedione) iron (III), and then mixed by stirring to obtain the adhesion of Example 1.剂 组合 物。 Composition. This adhesive composition was coated on a release film composed of a silicone resin-coated polyethylene terephthalate (PET) film, and then dried at 90 ° C to remove the solvent to obtain an adhesive layer. Adhesive sheet with a thickness of 25 μm.

Then, prepare a polyethylene terephthalate (PET) film with antistatic treatment and antifouling treatment on one side, and transfer the adhesive sheet to the polyethylene terephthalate (PET) film. On the side opposite to the surface subjected to antistatic treatment and antifouling treatment, a PET film / adhesive layer / peeling film (PET film coated with silicone resin) ) "The surface protective film of Example 1 having a laminated structure.

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

Except that the composition of each additive was adjusted as shown in (C) to (F) and (J) of Table 2, the same operation as in the surface protective film of Example 1 was performed to obtain Examples 2 to 6 and Comparative surface protection films of Examples 1 to 3. 【Table 2】

Tables 1 and 2 are tables in which the entire table showing the mixing ratio of each component is divided into two parts, and the values in parentheses represent the weight parts of each component obtained by setting the total amount of group (A) to 100 parts by weight. Value. The ratio of (E) / (D) is shown in Table 3. In addition, the compound names corresponding to the abbreviations of the respective components used in Tables 1 and 2 are shown in Tables 4 and 5. In addition, Coronate (コ ロ ネ ー ト, registered trademark) HX, Coronate HL and Coronate L are the trade names of Nippon Polyurethane Industry Co., Ltd., Takenate (タ ケ ネ ー ト, registered trademark) D-140N, D- 127N and D-110N are trade names of Mitsui Chemicals Co., Ltd., and Desmodur (デ ス モ ジ ュ ー ル, registered trademark) N3400 is a trade name of Sumika Bayer Urethane Co., Ltd.

In Table 1, the (F-2) antistatic agent copolymerized in the copolymer (F-2) propylene fluorenyl group-containing ionic compound and the (F) antistatic agent added after polymerization are described in different columns, respectively. in. 【table 3】 【Table 4】 【table 5】

<Synthesis of difunctional isocyanate compound>

The difunctional isocyanate compounds of Synthesis Examples 1 and 2 were synthesized by the following method. That is, as shown in Tables 6 and 7, the diisocyanate and the diol compound were mixed at a molar ratio of NCO / OH = 16, reacted at 120 ° C for 3 hours, and then removed under reduced pressure using a thin film evaporation device. Unreacted diisocyanate yields the desired difunctional isocyanate compound. [Table 6] [Table 7]

＜ Test method and evaluation ＞

After the surface protective films of Examples 1 to 6 and Comparative Examples 1 to 3 were aged at 23 ° C and 50% RH for 7 days, the release film (a silicone resin-coated PET film) was peeled off to make adhesion. The agent layer was exposed and used as a sample for measuring surface resistivity.

Furthermore, the exposed surface protection film of the adhesive layer was bonded to the surface of the polarizing plate pasted on the liquid crystal cell through the adhesive layer, and after being left for 1 day, the autoclave treatment was performed at 50 ° C and 5 atmospheres for 20 minutes. After being left at room temperature for 12 hours, it was used as a sample for measuring adhesion, peeling static voltage, reworkability, and durability.

＜ Adhesiveness ＞

A tensile tester was used to peel the measurement sample obtained above at a low peel speed (0.3 m / min) and a high peel speed (30 m / min) in a direction of 180 ° (a 25 mm wide surface protective film was laminated) A sample formed on the surface of a polarizing plate) was measured for peeling strength, and this peeling strength was used as an adhesive force.

＜ Surface resistivity ＞

After aging and before bonding to the polarizing plate, peel off the peeling film (PET film coated with silicone resin) to expose the adhesive layer, and use a resistivity meter (model HirestaUP-HT450 (HI-RESPU UP-HT450) Mitsubishi Chemical Analysis) (Manufactured by Mitsubishi Chemical Analytech Co., Ltd.), and measured the surface resistivity of the adhesive layer.

＜ Peeling Static Voltage ＞

Using high-precision electrostatic sensors SK-035 and SK-200 (manufactured by Keyence Corporation), the measurement was performed at 180 ° at a tensile speed of 30 m / min. At the time of peeling, the voltage (static voltage) generated by the electrification of the polarizing plate was taken as the maximum value of the measured value as the peeling static voltage.

＜ Reworkability ＞

After drawing on the surface protective film of the measurement sample obtained above with a ball pen (load 500 g, 3 times back and forth), peel the surface protective film from the polarizing plate, observe the surface of the polarizing plate, and confirm whether the pollution is transferred to the polarizing plate. . Evaluation target standard: When the pollution is not transferred to the polarizing plate, it is evaluated as "○"; when it is confirmed that the trajectory drawn along the ball pen is at least partially transferred, it is evaluated as "△"; when it is confirmed that there is When contamination was transferred and the release of the adhesive was also confirmed from the surface of the adhesive, it was evaluated as “×”.

＜ Storage period ＞

Immediately after the additives (C) to (F) and (J) were blended, the viscosity η ₀ (initial viscosity) of the adhesive composition was measured, and then the adhesive composition was left at 23 ° C. for 8 hours in a sealed state to measure the adhesive. Composition viscosity η ₁ (viscosity after 8 hours). As an index of the storage period, the value of η ₁ when η ₀ was 1.0, that is, the ratio of η ₁ / η ₀ was obtained. The evaluation criteria are as follows: when the viscosity after 8 hours is less than 1.25 times the initial viscosity, it is evaluated as "○", when it is 1.25 times or more and less than 1.50 times, it is evaluated as "△", and it is left at 1.50 times or after 8 hours. When gelation occurred, it was evaluated as "×".

＜ Durability ＞

After leaving the measurement sample obtained at 60 ° C and 90% RH for 250 hours, the sample was taken out and placed at room temperature for another 12 hours. Then, the adhesive force was measured, and it was confirmed whether it was obvious compared with the initial adhesive force. Increase. Evaluation target criteria: When the adhesion after the test is 1.5 times or less the initial adhesion, it is evaluated as "○", and when it exceeds 1.5 times, it is evaluated as "×".

The evaluation results are shown in Table 8. In the surface resistivity, “mE + n” is used to represent “m × 10 ^{+ n} ” (where m is an arbitrary real number and n is a positive integer). [Table 8]

For the surface protective films of Examples 1 to 6, the adhesive force at a low peeling speed of 0.3 m / min was 0.05 to 0.1 N / 25 mm, and the adhesive force at a high peeling speed of 30 m / min was 1.0 N / 25 mm. The surface resistivity is below 9.0 × 10 ⁺¹¹ Ω / □, and the peeling static voltage is ± 0 to 0.5 kV. Furthermore, after drawing on the surface protective film with an adhesive pen through an adhesive layer, the surface resistivity is not shown on the adherend. Contamination is transferred, the storage period is long, and the durability after being placed in an environment of 60 ° C and 90% RH for 250 hours is also excellent.

That is, it has excellent antistatic performance, excellent balance of adhesive force at low peeling speed and high peeling speed, and long storage period, durability, and reworkability.

In addition, the surface protective films of Examples 1 to 6 have high safety because the adhesive composition does not contain an organic tin compound.

The surface protective film of Comparative Example 1 may be because it does not contain a (C) difunctional or higher isocyanate compound as a crosslinking agent, and has a low peeling speed of 0.3 m / min and a high peeling speed of 30 m / min. The adhesive force is too large, the surface resistivity and the peeling static voltage are high, and the reworkability and durability are poor.

The surface protective film of Comparative Example 2 may have a high peeling static voltage because the ratio of the (E) keto-enol tautomer compound to the (D) metal chelate cross-linking catalyst is small. , Short storage period, and poor durability.

The surface protection film of Comparative Example 3 may be because the ratio of the (E) keto-enol tautomer compound to the (D) metal chelate cross-linking catalyst is small, and its storage period becomes too short. Since the cross-linking has been performed before coating, coating cannot be performed.

In this way, the surface protective films of Comparative Examples 1 to 3 cannot satisfy both of the excellent antistatic properties, the balance of the adhesive force at the low peeling speed and the high peeling speed is excellent, and the storage period is long, the durability and All refining properties are also excellent, such as excellent reworkability.

Claims (4)

An adhesive composition containing an acrylic copolymer, an antistatic agent, and a cross-linking agent, characterized in that the acrylic copolymer is composed of 100 parts by weight of carbon of the (A) alkyl group of the acrylic copolymer. 50 to 98 parts by weight of at least one or more of (meth) acrylate monomers having C4 to C18 atoms, and 0.1 to 10 parts by weight of one or more of (B) hydroxyl-containing copolymerizable monomers, and as Copolymerizable monomers, one or more of carboxyl-containing monomers total 0 to 1 part by weight, one or more of hydroxyl-free and nitrogen-containing vinyl monomers total 0 to 20 parts by weight, and polyalkylene glycol mono A copolymer composed of one or more (meth) acrylate monomers copolymerized in a total amount of 0 to 50 parts by weight; the antistatic agent is an ionic compound having a melting point of 25 to 50 ° C; The acrylic copolymer, wherein the adhesive composition contains (D) 0.001 to 0.5 parts by weight of a metal chelate cross-linking catalyst and (E) 0.1 to 200 parts by weight of a keto-enol tautomer compound, (E) / (D) ratio by weight is greater than 80 and less than 700; the crosslinking catalyst of the (D) metal chelate is The group consisting of aluminum chelate, titanium chelate, iron chelate consisting of at least one or more selected. The adhesive composition according to claim 1, wherein the (B) hydroxyl-containing copolymerizable monomer is selected from 8-hydroxyoctyl (meth) acrylate and 6-hydroxyhexyl (meth) acrylate , 4-hydroxybutyl (meth) acrylate, 2-hydroxyethyl (meth) acrylate, N-hydroxy (meth) acrylamide, N-hydroxymethyl (meth) acrylamide, N-hydroxyl At least one selected from the group consisting of ethyl (meth) acrylamide. An adhesive film is characterized in that it is formed by forming an adhesive layer on one or both sides of a resin film, and the adhesive layer is made to pass the adhesive composition according to any one of claims 1 or 2. United. A surface protection film, which is formed by forming an adhesive layer on one side of a resin film, and the adhesive layer is obtained by crosslinking the adhesive composition according to any one of claims 1 or 2. to make.