TW201602277A - Adhesive composition and surface protection film - Google Patents

Abstract

The present invention provides an adhesive composition and a surface-protective film that have a long pot life and a fast crosslinking rate without using an organic tin compound. The present invention, with respect to 100 parts by weight of a copolymer of (A) at least one (meth)acrylic acid ester monomer having a C4 to C18 alkyl group and, as copolymerizable monomers, (B) hydroxyl group-containing copolymerizable monomers, contains 0.1 to 10 parts by weight of (C) a bifunctional or higher isocyanate compound, 0.001 to 0.5 parts by weight of (D) a cross-linking promoting agent of a metal chelate compound, and 0.1 to 300 parts by weight of (E) a keto-enol tautomer compound, wherein the parts by weight ratio of (E)/(D) is 70 to 1,000.

Description

Adhesive composition and surface protection film

The present invention relates to a binder composition and a surface protective film. more In detail, since the use of an organotin compound which adversely affects the environment has been restricted in recent years, the present invention relates to providing an organotin compound without using a crosslinking catalyst of a metal chelate other than an organotin compound. In the case of a binder having a long storage period and a fast crosslinking speed, and a surface protective film.

Excellent transparency for adhesive compositions for optical applications In view of the above, an acrylic binder composed of a copolymer obtained by copolymerizing an alkyl (meth)acrylate as a main component and an acrylic monomer having a hydroxyl group or a carboxyl group as a functional group is preferably used. Further, a binder which appropriately adjusts various physical properties such as the adhesion force of the binder layer is required. In particular, in order to be suitable for the manufacturing process of factory production, the adhesive layer for the surface protective film is required to be suitable for bonding by an automatic bonding device, and the bonding force at a low peeling speed and a high peeling speed. Excellent balance. Further, a binder composition excellent in various physical properties such as a long storage period other than the balance of the bonding force is required.

For this method of adjusting various physical properties of the binder layer That is, by using the hydroxy group contained in the acrylic binder composed of the copolymer An isocyanate crosslinking agent or an epoxy crosslinking agent which reacts with a functional group such as a carboxyl group or a carboxyl group is subjected to a crosslinking reaction to adjust a binding force, a cohesive force, and the like.

In the past, as a crosslinking agent for acrylic adhesives, usually An isocyanate crosslinking agent is used. Further, in the crosslinking reaction using an isocyanate crosslinking agent, a metal chelate compound is often used as a catalyst for promoting the crosslinking reaction.

In general, from the viewpoint of excellent reaction rate of the crosslinking reaction, dibutyltin dilaurate, which is an organotin compound, is used as a catalyst for the crosslinking reaction. However, since the dibutyltin compound exhibits harmful toxicity, it is currently avoided.

Therefore, there is a need for a crosslinking catalyst which is an alternative to a dibutyltin compound which can be used in combination with an isocyanate crosslinking agent and which is inexpensive and has a high reaction rate of a crosslinking reaction, but it is difficult to develop and obtain.

In view of this situation, Patent Document 1 discloses the following contents: The crosslinking catalyst which can be used in combination with the isocyanate crosslinking agent is preferably an iron chelate compound in the metal chelate compound; and is particularly preferred because it has excellent catalytic activity of the tris(ethinylacetone)-coordinated iron.

However, an acrylic binder combination containing a crosslinking catalyst The cross-linking reaction is slowly carried out even during standing at room temperature. Therefore, in the industrial production of the binder, a crosslinking catalyst and a reaction inhibitor are usually used in combination in order to stop the crosslinking reaction after the raw material of the binder composition is prepared and the crosslinking reaction is started.

Regarding the combined use of the crosslinking catalyst and the reaction inhibitor, Patent Document 2 discloses a method for producing a polyurethane in which a reactive polyurethane mixture containing at least one metal acetoacetone and acetamidine is used. A catalyst system in which a mixture of acetone is obtained and the weight ratio of the aforementioned metal acetamidine acetone to the aforementioned acetamidine acetone is 2:1.

[Previous Technical Literature] [Patent Literature]

[Patent Document 1] JP-A-2011-001440

[Patent Document 2] JP-A-2008-285681

In the binder composition described in the patent document 1, the amount of addition of a metal compound (crosslinking catalyst) to a copolymer containing a hydroxyl group and a carboxyl group as a constituent monomer unit of (meth) acrylate is proposed. However, the amount of the crosslinking inhibitor added is not described. In addition, in the method of suppressing the viscosity increase rate after the crosslinking agent is prepared in the adhesive composition, the method of using a reaction inhibitor, the method of adding a solvent which suppresses viscosity increase, and the use of the method of using the reaction inhibitor are mentioned. A method of blocking a crosslinking agent such as a blocked isocyanate or the like, but is not specifically described.

Further, Patent Document 2 discloses a method for producing a polyurethane in which a catalyst system is used which does not cause early curing and is excellent even if a metal acetoacetone catalyst such as iron or copper which is highly active at a low temperature is used. The stability and good catalytic activity of the metal acetamidine acetone and acetamidine acetone.

However, in the method described in Patent Document 2, the weight ratio of metal acetoacetone to acetamidine is 2:1, but in the manufacturing process of the acrylic binder In the case where the blending ratio is used, the crosslinking reaction cannot be temporarily stopped.

The present invention has been made in view of the above circumstances, and the subject matter thereof is There is provided a binder composition and a surface protective film which have a long shelf life and a fast crosslinking speed without using an organotin compound.

In order to solve the above problems, the present invention provides a binder composition in which at least one of C4 to C18 (meth) acrylate monomers having a carbon number of (A) alkyl group and a copolymerizable monomer are used. 100 parts by weight of the copolymer of the group (B) hydroxyl group-containing copolymerizable monomer, containing (C) 0.1 to 10 parts by weight of a difunctional or higher isocyanate compound, and 0.001 to 0.5 weight of a crosslinking catalyst of the (D) metal chelate compound And (E) the keto-enol tautomer compound is 0.1 to 300 parts by weight, and the ratio by weight of (E)/(D) is 70 to 1,000.

Further, it is preferred that the viscosity of the above-mentioned binder composition after storage of the above-mentioned binder composition at 23 ° C for 8 hours is less than 1.25 times that of the viscosity just after blending.

Further, it is preferred that the (B) hydroxyl group-containing copolymerizable monomer is selected from the group consisting of 8-hydroxyoctyl (meth)acrylate, 6-hydroxyhexyl (meth)acrylate, and (meth)acrylic acid 4- Hydroxybutyl ester, 2-hydroxyethyl (meth)acrylate, N-hydroxy(meth)acrylamide, N-methylol (meth) acrylamide, N-hydroxyethyl (meth) propylene oxime At least one or more of the compounds consisting of amines.

Further, in the above-mentioned (C) difunctional or higher isocyanate compound, a difunctional isocyanate compound is preferably a compound produced by reacting a diisocyanate compound with a diol compound, and an acyclic aliphatic isocyanate compound. As the aforementioned diisocyanate compound, it is an aliphatic diisocyanate The ester is preferably a compound selected from the group consisting of tetramethylene diisocyanate, pentamethylene diisocyanate, hexamethylene diisocyanate, trimethyl hexamethylene diisocyanate, and lysine diisocyanate. One of the groups is constructed. Further, as the diol compound, it is preferably selected from the group consisting of 2-methyl1,3-propanediol, 2,2-dimethyl-1,3-propanediol, and 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 monohydroxyl One of a group of compounds consisting of pivalate, polyethylene glycol, and polypropylene glycol.

Further, in the above-mentioned (C) difunctional or higher isocyanate compound, the trifunctional isocyanate compound is preferably selected from the group consisting of isocyanurate and isophorone diisocyanate compounds derived from a hexamethylene diisocyanate compound. Adduct of cyanurate, hexamethylene diisocyanate compound, adduct of isophorone diisocyanate compound, biuret of hexamethylene diisocyanate compound, shrinkage of isophorone diisocyanate compound Addition of isocyanurate of diurea, toluene diisocyanate compound, isocyanurate of benzodimethyl diisocyanate compound, isocyanurate of hydrogenated dimethyl diisocyanate compound, toluene diisocyanate compound At least one or more of the compound group consisting of the adduct of the benzodimethyl diisocyanate compound and the adduct of the hydrogenated dimethyl diisocyanate compound.

Further, in the above binder composition, as the aforementioned crosslinking reminder The agent is preferably free of organotin compounds.

In addition, the aforementioned copolymer is included as a group of other copolymerizable monomers. At least one or more acrylic polymers containing a carboxyl group-containing monomer and a hydroxyl group-free and nitrogen-containing vinyl monomer are preferred.

In addition, the gel fraction of the aforementioned binder composition after crosslinking is relatively Good is 90~100%.

Further, it is preferably a viscosity obtained by crosslinking the above-mentioned binder composition. The bonding layer has a bonding force of 0.05 to 0.2 N/25 mm at a low peeling speed of 0.3 m/min, and a bonding force of 2.0 N/25 mm or less at a high peeling speed of 30 m/min.

Moreover, the present invention provides a bonded film which is in a resin film A layer of a binder is formed on one or both sides, and the layer of the binder is formed by crosslinking the binder composition.

Moreover, the present invention provides a surface protective film which is in a resin A surface protective film formed by forming a binder layer on one surface of the film, and the binder layer is formed by crosslinking the binder composition.

In addition, the surface protective film of the present invention can be used as a surface of a polarizing plate The use of the protective film is used.

In addition, the surface protective film of the present invention can be used as a precision electric/electrical The use of a surface protective film for a sub-assembly, which is selected from any of a group of precision electrical/electronic components consisting of a flexible printed circuit board, a rigid printed circuit board, and a transparent conductive film. .

According to the present invention, it is possible to provide a binder composition and a surface protective film which have a long shelf life and a fast crosslinking speed without using an organotin compound.

Further, according to the surface protective film of the present invention, the adhesive composition does not contain a toxic organotin compound, and therefore has high safety.

[Implementation of the Invention]

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

The binder composition of the present invention is characterized in that at least one of the (meth) acrylate monomers having a CA to C18 carbon number of the (A) alkyl group and the group as a copolymerizable monomer (B) 100 parts by weight of the copolymer of the hydroxyl group-containing copolymerizable monomer, containing (C) 0.1 to 10 parts by weight of the difunctional or higher isocyanate compound, (D) 0.001 to 0.5 part by weight of the crosslinking catalyst of the metal chelate compound, and (E) The keto-enol tautomer compound is 0.1 to 300 parts by weight, and the ratio by weight of (E)/(D) is 70 to 1,000.

The foregoing copolymer is included as a carboxyl group as another copolymerizable monomer group. It is preferred that at least one of the monomer, the hydroxyl group-free, and the nitrogen-containing vinyl monomer is used.

As the (A) alkyl group, the number of carbon atoms is C4 to C18 (methyl) Examples of the acrylate monomer include butyl (meth)acrylate, isobutyl (meth)acrylate, amyl (meth)acrylate, hexyl (meth)acrylate, and heptyl (meth)acrylate. Octyl (meth)acrylate, isooctyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, decyl (meth)acrylate, isodecyl (meth)acrylate, (methyl) Ethyl acrylate, isodecyl (meth)acrylate, undecyl (meth)acrylate, dodecyl (meth)acrylate, tridecyl (meth)acrylate, (methyl) Tetradecyl acrylate, pentadecyl (meth) acrylate, cetyl (meth) acrylate, (A) Pentadecyl acrylate, octadecyl (meth) acrylate, myristyl (meth) acrylate, isotetradecyl (meth) acrylate, cetyl (meth) acrylate, Isohexadecyl (meth)acrylate, stearyl (meth)acrylate, isostearyl (meth)acrylate, and the like.

The (A) alkyl group has a C4 to C18 (meth) acrylate monomer content of 50 to 98 parts by weight, based on 100 parts by weight of the copolymer.

As (B) a hydroxyl group-containing copolymerizable monomer, there may be mentioned: (A) (meth)acrylic acid hydroxyalkyl group such as 8-hydroxyoctyl acrylate, 6-hydroxyhexyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, 2-hydroxyethyl (meth) acrylate Ester; N-hydroxy (meth) acrylamide, N-hydroxymethyl (meth) acrylamide, N-hydroxyethyl (meth) acrylamide, etc. Hydroxy-containing (meth) acrylamide Classes, etc.

Preferably, the hydroxyl group-containing copolymerizable monomer is selected from the group consisting of 8-hydroxyoctyl (meth)acrylate, 6-hydroxyhexyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, a compound consisting of 2-hydroxyethyl methacrylate, N-hydroxy(meth) acrylamide, N-methylol (meth) acrylamide, and N-hydroxyethyl (meth) acrylamide At least one or more of the groups.

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

For the aforementioned copolymer, it can also be used as a group of other copolymerizable monomers including a carboxyl group-containing monomer, a hydroxyl group-free nitrogen-containing vinyl monomer, a polyalkylene glycol mono(meth)acrylate monomer. At least one of the above.

Preferably, the aforementioned carboxyl group-containing monomer is selected from (meth) propyl group Acrylic acid, carboxyethyl (meth)acrylate, carboxypentyl (meth)acrylate, 2-(methyl)propenyloxyethylhexahydrophthalic acid, 2-(methyl)propenyloxy Propyl hexahydrophthalic acid, 2-(meth) propylene oxiranyl ethyl phthalate, 2-(methyl) propylene methoxyethyl succinic acid, 2-(methyl) propylene oxime At least one or more of the compound group consisting of phenylethylmaleic acid, carboxypolycaprolactone mono(meth)acrylate, and 2-(meth)acryloxyethyltetrahydrophthalic acid.

When the copolymer described above as the other copolymerizable monomer group includes a carboxyl group-containing monomer, the content of the carboxyl group-containing monomer is preferably 0.1 to 1.0 part by weight based on 100 parts by weight of the above copolymer. The aforementioned copolymer may also be free of the aforementioned carboxyl group-containing monomer.

As the aforementioned polyalkylene glycol mono(meth)acrylate monomer, The compound may be a compound in which one of a plurality of hydroxyl groups of the polyalkylene glycol is esterified to a (meth) acrylate. Since the (meth) acrylate group is a polymerizable group, it can be copolymerized with the copolymer of the main component. The other hydroxyl group may be in an OH state, may be an alkyl ether such as methyl ether or diethyl ether, or may be a saturated carboxylic acid ester such as acetate.

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

It is preferable that the average number of repetitions of the alkylene oxide constituting the polyalkylene glycol chain in the polyalkylene glycol mono(meth)acrylate monomer is from 3 to 14. The "average repeat number of alkylene oxide" means the alkylene oxide in the "polyalkylene glycol chain" portion contained in the molecular structure of the polyalkylene glycol mono(meth)acrylate monomer. The average number of unit repetitions.

As the aforementioned polyalkylene glycol mono(meth)acrylate monomer, Preferably, it is selected from the group consisting of polyalkylene glycol mono (meth) acrylate, methoxy polyalkylene glycol (meth) acrylate, ethoxy polyalkylene glycol (meth) acrylate At least one of the above.

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 - 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 poly butyl 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; ethoxypolyethylene glycol -(Meth)acrylate, ethoxypolypropylene glycol-(meth)acrylate, ethoxylated polybutylene glycol-(meth)acrylate, ethoxy-polyethylene glycol-polypropylene glycol-(A Acrylate, ethoxy-polyethylene glycol-polybutylene glycol-(meth) propylene Esters, ethoxylated - polyethylene glycol - polypropylene glycol - (meth) acrylate, ethoxy - polyethylene glycol - polypropylene glycol - polyethylene glycol - (Meth) acrylate, etc.

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

As the above-mentioned vinyl monomer containing no hydroxyl group and containing nitrogen, A vinyl monomer containing a guanamine bond, a vinyl monomer containing an amino group, a vinyl monomer having a nitrogen-containing heterocyclic structure, and the like. More specifically, N-vinyl-2-pyrrolidone, N-vinylpyrrolidone, methylvinylpyrrolidone, N-vinylpyridine, N-vinylacridone, N-vinylpyrimidine, N-vinylpyridazine, N-vinylpyrazine, N-vinylpyrrole, N-vinylimidazole, N-vinyloxazole, N-vinylmorpholine, N-vinylcaprolactam, N a cyclic nitrogen vinyl compound having an N-vinyl substituted heterocyclic ring structure such as vinyl dodecanoin; N-(meth)acryl hydrazinomorpholine, N-(methyl) acrylonitrile fluorene Pyrazine, N-(methyl) acrylonitrile aziridine, N-(methyl) propylene decylpyridinium, N-(methyl) propylene decyl pyrrolidine, N-(methyl) propylene fluorenyl a heterocyclic structure having an N-(meth)acrylinyl group-substituted heterocyclic ring such as acridine, N-(methyl)acrylonitrile-azetidene or N-(methyl)propenylazepane a cyclic nitrogen-vinyl compound; a cyclic nitrogen-oxyethylene having a heterocyclic structure containing a nitrogen atom and a vinyl-based unsaturated bond in the ring, such as N-cyclohexylmaleimide or N-phenylmaleimide. Base compound; (meth) acrylamide, N-methyl (meth) propylene oxime An unsubstituted or monoalkyl-substituted (meth) acrylamide such as N-isopropyl (meth) acrylamide or N-tert-butyl (meth) acrylamide; N,N-dimethyl (Meth) acrylamide, N,N-diethyl(meth) acrylamide, N,N-dipropyl acrylamide, N,N-diisopropyl(meth) acrylamide, N,N-dibutyl(methyl)propane Enamine, N-ethyl-N-methyl (meth) acrylamide, N-methyl-N-propyl (meth) acrylamide, N-methyl-N-isopropyl (A Dialkyl substituted (meth) acrylamide such as acrylamide; N,N-dimethylaminomethyl (meth) acrylate, N,N-dimethylaminoethyl (meth) acrylate Ester, N,N-dimethylaminopropyl (meth) acrylate, N,N-dimethylaminoisopropyl (meth) acrylate, N,N-dimethylaminobutyl (methyl) Acrylate, N,N-diethylaminomethyl (meth) 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- Dialkylamino (meth) acrylate such as dibutylaminoethyl (meth) acrylate or t-butylaminoethyl (meth) acrylate; N, N-dimethylaminopropyl (methyl) Acrylamide, N,N-diethylaminopropyl(meth)acrylamide, N,N-dipropylaminopropyl(meth)acrylamide, N,N-diisopropylamino Propyl (meth) acrylamide, N- -N-methylaminopropyl (meth) acrylamide, N-methyl-N-propylaminopropyl (meth) acrylamide, N-methyl-N-isopropylaminopropyl N,N-dialkyl substituted aminopropyl (meth) acrylamide of (meth)acrylamide or the like; N-vinylformamide, N-vinylacetamide, N-vinyl-N - N-vinyl carboxylic acid amides such as methyl acetamide; N-methoxymethyl (meth) acrylamide, N-ethoxyethyl (meth) acrylamide, N-butyl (meth)acrylamide, etc. such as oxymethyl (meth) acrylamide, diacetone acrylamide, N, N-methylene bis(meth) acrylamide, etc.; (meth) acrylonitrile Unsaturated carboxylic acid nitriles;

With respect to 100 parts by weight of the aforementioned copolymer, it is preferred that the aforementioned The content of the hydroxyl group-containing nitrogen-containing vinyl monomer is 0 to 20 parts by weight. The aforementioned copolymerization The vinyl monomer having no hydroxyl group and containing nitrogen may not be contained.

As the (C) difunctional or higher isocyanate compound, as long as it is At least one or two or more selected from the group consisting of polyisocyanate compounds having at least two or more isocyanate (NCO) groups in one molecule may be used. The polyisocyanate compound includes a classification of an aliphatic isocyanate, an aromatic isocyanate, an acyclic isocyanate, an alicyclic isocyanate, and the like, 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), benzodimethyl diisocyanate (XDI), hydrogenated dimethyl diisocyanate (H6XDI), dimethyl diphenylene diisocyanate (TOID), toluene diisocyanate (TDI An aromatic isocyanate compound.

Examples of the trifunctional or higher isocyanate compound include a biuret modified product or a isocyanurate modified product of a difunctional isocyanate compound (a compound having two NCO groups in one molecule), and a trihydroxyl group. An adduct (polyol modified product) of a trivalent or higher polyvalent alcohol (a compound having at least three or more OH groups in one molecule) such as a propane (TMP) or glycerin.

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

Further, as the (C-1) trifunctional isocyanic acid used in the present invention The ester compound preferably comprises a (C-1-1) first aliphatic isocyanate selected from the group consisting of (C-1-1) At least one or more of the compound group and at least one selected from the group consisting of (C-1-2) second aromatic isocyanate compounds, wherein the (C-1-1) first aliphatic isocyanate compound group Is an isocyanurate of a hexamethylene diisocyanate compound, an isocyanurate of an isophorone diisocyanate compound, an adduct of a hexamethylene diisocyanate compound, or an isophorone diisocyanate compound An adduct, a biuret of a hexamethylene diisocyanate compound, and a biuret of an isophorone diisocyanate compound; the (C-1-2) second aromatic isocyanate compound group is composed of toluene Isocyanurate of diisocyanate compound, isocyanurate of benzodimethyl diisocyanate compound, isocyanurate of hydrogenated dimethylated diisocyanate compound, adduct of toluene diisocyanate compound, benzene An adduct of a methyl diisocyanate compound and an adduct of a hydrogenated dimethyl diisocyanate compound. Preferably, the (C-1-1) first aliphatic isocyanate compound group and the (C-1-2) second aromatic isocyanate compound group are used in combination. In the present invention, as the (C-1) trifunctional isocyanate compound, at least one or more selected from the group consisting of (C-1-1) first aliphatic isocyanate compounds and selected from (C-1-2) are used in combination. At least one or more of the second aromatic isocyanate compound group can further improve the balance of the bonding force in the low-speed peeling region and the high-speed peeling region.

Further, it is preferred that the (C-1) trifunctional isocyanate compound contains at least one selected from the group consisting of the above (C-1-1) first aliphatic isocyanate compound group and is selected from the above (C-1-2). At least one or more of the diaromatic isocyanate compound groups are used in an amount of from 0.5 to 5.0 parts by weight based on 100 parts by weight of the copolymer. Further, as at least one or more selected from the group consisting of (C-1-1) first aliphatic isocyanate compounds and selected from (C-1-2) second aromatics The mixing ratio of at least one of the isocyanate compound groups is preferably (C-1-1): (C-1-2) in the range of 10%: 90% to 90%: 10% by weight.

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

For example, when the formula "O=C=NXN=C=O" (where X is a divalent group), the diisocyanate compound is represented by the formula "HO-Y-OH" (wherein Y is a divalent group) In the case of the diol compound, a compound which is formed by reacting a diisocyanate compound with a diol compound, for example, a compound represented by the following formula Z can be mentioned.

[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 also include a compound of the formula Z in which n is 0 (diisocyanate compound which is not reacted with respect to the diol compound), and a compound having n as an integer of 1 or more as an essential component is preferable. . The difunctional acyclic aliphatic isocyanate compound may also be a mixture of a plurality of compounds different from n in the general formula Z.

The diisocyanate compound represented by the formula "O=C=N-X-N=C=O" is an aliphatic diisocyanate. X is preferably an acyclic aliphatic divalent group. The aliphatic diisocyanate is preferably selected from the group consisting of tetramethylene diisocyanate, pentamethylene diisocyanate, hexamethylene diisocyanate, and trimethyl One or two or more kinds of compound groups consisting of hexamethylene diisocyanate and lysine diisocyanate are used.

The diol compound represented by the formula "HO-Y-OH" is aliphatic alcohol. Y is preferably an acyclic aliphatic divalent group. The diol compound is preferably selected from the group consisting of 2-methyl1,3-propanediol, 2,2-dimethyl-1,3-propanediol, and 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 monohydroxynepenta One or two or more of the compound groups consisting of an acid ester, polyethylene glycol, and polypropylene glycol.

Preferred is the aforementioned (C-1) trifunctional isocyanate compound and (C-2) The weight ratio (C-1/C-2) of the difunctional isocyanate compound is from 1 to 90. The (C) difunctional or higher isocyanate compound is preferably 0.1 to 10 parts by weight based on 100 parts by weight of the copolymer.

When a polyisocyanate compound is used as a crosslinking agent, (D) metal The crosslinking catalyst of the chelate compound may be a compound which functions as a catalyst for the reaction (crosslinking reaction) between the copolymer and the crosslinking agent, and examples thereof include an amine compound such as a tertiary amine and a metal chelate compound. Organic metal compounds such as organotin compounds, organic lead compounds, and organozinc compounds. A metal chelate compound is employed as the crosslinking catalyst in the present invention.

The metal chelate compound is a compound in which one or more multidentate 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 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, n 0. When m is 2 or more, m of L may be the same ligand or a different ligand. When n is 2 or more, n of X may be the same ligand or a different ligand.

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

Examples of the polydentate ligand L include methyl ethyl acetate, ethyl acetate, octyl acetate, ethyl acetoacetate, lauryl acetate, and stearyl acetate. beta] - keto ester; Acetylacetonates: β (alias 2,4-pentanedione), 2,4-hexanedione, benzoyl acetone, etc. - dione. These are keto-enol tautomer compounds, and in the polydentate ligand L, they may also be enolates (for example, acetoacetate) in which an enol is deprotonated.

Examples of the monodentate ligand X include a halogen atom such as a chlorine atom or a bromine atom, a pentamidine group, a hexyl group, a 2-ethylhexyl group, a octyl group, an anthracenyl group, a fluorenyl group, and a fluorenyl group. An alkoxy group such as a stearyl group or an alkoxy group such as a methoxy group, an ethoxy group, a n-propoxy group, an isopropoxy group or a butoxy group.

Specific examples of the metal chelate compound include: three (2, 4- Ethyl pentoxide) iron (III), triethyl sulfonium iron, triethyl hydrazine acetonide, triethyl hydrazine acetonide, diethyl acetonide zinc, triethyl acetonide aluminum, tetraethylene acetonide zirconium, three (2, 4 -hexanedione) iron (III), bis(2,4-hexanedione) zinc, tris(2,4-hexanedione)titanium, tris(2,4-hexanedione)aluminum, tetra (2, 4-hexanedione) Zirconium and the like.

Examples of the organotin compound include dialkyl tin oxides. a fatty acid salt of a dialkyl tin, a fatty acid salt of stannous, and the like. In the past, dibutyltin compounds have been used in most cases, but in recent years, the toxicity problem of organotin compounds has been pointed out, and in particular, tributyltin (TBT) contained in dibutyltin compounds is also considered as an endocrine disruptor. From a safety point of view, it is preferred It is a long-chain alkyl tin compound such as a dioctyltin compound. Specific examples of the organotin compound include dioctyltin oxide, dioctyltin dilaurate, and the like. Although it is also possible to use the Sn compound temporarily, in view of the tendency to use a more safe substance in the future, it is preferred to use a metal chelate compound of Al, Ti, Fe or the like which is safer than Sn.

The metal chelate compound in the binder composition of the present invention preferably contains at least one selected from the group consisting of aluminum chelate compounds, titanium chelate compounds, and iron chelate compounds.

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

Examples of the (E) keto-enol tautomer compound include methyl acetonitrile acetate, ethyl acetate, octyl acetate, ethyl acetoacetate, lauryl acetate, and acetamidine. acetic acid esters such as stearyl acyl beta] - keto ester; beta] acetyl acetone, 2,4-hexanedione, benzoyl acetone, etc. - dione. In the binder composition using a polyisocyanate compound as a crosslinking agent, by blocking the isocyanate group of the crosslinking agent, it is possible to suppress excessive increase or gelation of the viscosity of the binder composition after the preparation of the crosslinking agent. Phenomenon, can extend the shelf life of the binder composition.

The content of the (E) keto-enol tautomer compound is preferably from 0.1 to 300 parts by weight based on 100 parts by weight of the copolymer.

Contrary to the crosslinking catalyst of (D) metal chelate, (E) The keto-enol tautomer compound has an effect of inhibiting crosslinking, and therefore, it is preferred to appropriately set the ratio of the (E) keto-enol tautomer compound to the crosslinking catalyst of the (D) metal chelate compound. . In order to extend the storage of the binder composition In order to improve storage stability, it is preferred that the (E) keto-enol tautomer compound/(D) metal chelate crosslinking catalyst has a weight ratio (E)/(D) which is high. Preferably, the value of (E)/(D) is in the range of 70 to 1000, more preferably 70 to 800, and most preferably 80 to 600.

A binder composition that extends shelf life based on the present invention, Specifically, it is preferred that the viscosity of the above-mentioned binder composition after storage of the above-mentioned binder composition at 23 ° C for 8 hours is less than 1.25 times that of the viscosity immediately after blending. Thereby, the binder composition which suppresses the viscosity increase after preparation can be obtained.

The adhesive composition of the present invention may include antistatic as an additive Additives such as an electric agent, a polyether siloxane compound, and other conventional antioxidants.

As the antistatic agent, a binder composition can be mentioned. An antistatic agent contained therein and an antistatic agent copolymerized in the aforementioned copolymer. The antistatic agent is preferably contained in an amount of from 0.05 to 5.0 parts by weight based on 100 parts by weight of the copolymer.

The antistatic agent has a melting point of 25 ° C to 50 ° C, and is preferably an ionic compound which is solid at a temperature of 25 ° C and/or an ionic compound containing an acryl oxime group. Since these antistatic agents have a low melting point and a long-chain alkyl group, they are presumed to have high affinity with an acrylic copolymer.

The ionic compound having a melting point of 25 to 50 ° C is an ionic compound having a cation and an anion, and examples of the cation include a pyridinium cation, an imidazolium cation, a pyrimidine cation, a pyrazolium cation, a pyrrolidinium cation, and an ammonium salt. a nitrogen-containing phosphonium cation such as a cation, or a phosphonium cation or a phosphonium cation, and the anion is hexafluorophosphate (PF ₆ ^- ), thiocyanate (SCN ^- ), alkylbenzenesulfonate (RC ₆ H ₄ SO ₃ ^- ) , perchlorate (ClO ^4-), tetrafluoroborate (BF ₄ ^-), bis (fluorosulfonyl acyl) (PEI) root (FSI), bis (trifluoromethanesulfonyl acyl) (PEI) root (TFSI a compound of an inorganic or organic anion such as triflate (TF). It is preferably a 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 of the substituent, the number, and the like. The cation is preferably a quaternary nitrogen sulfonium cation, and examples thereof include a quaternary pyridinium cation such as 1-alkylpyridinium (having a substituent or a substituent at a carbon atom of 2 to 6), and 1,3. a quaternary ammonium cation such as a quaternary imidazolium cation or a tetraalkylammonium such as a dialkylimidazolium (a carbon atom at the 2, 4 or 5 position may have a substituent or a substituent).

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

The ionic compound containing an acryl fluorenyl group is an ionic compound having a cation and an anion, and the cation is a (meth) propylene decyloxyalkyltrialkylammonium (R ₃ N ⁺ -C _n H _2n -OCOCQ =CH ₂ , wherein Q=H or CH ₃ , R=alkyl), etc. (meth)acryloyl group-containing cation; anion is hexafluorophosphate (PF ₆ ^- ), thiocyanate (SCN ^- ), inorganic or organic such as organic sulfonate (RSO ₃ ^- ), perchlorate (ClO ₄ ^- ), tetrafluoroborate (BF ₄ ^- ), fluorenium iodide (R ^F ₂ N ^- ) Anionic compound. (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 ruthenium root containing F include bis(fluorosulfonyl) ruthenium root [(FSO ₂ ) ₂ N ^- ], bis(trifluoromethanesulfonyl) fluorenylene root [(CF _{3 )} SO ₂ ) ₂ N ^- 〕, bis(sulfonyl sulfonyl) ruthenium root [(C ₂ F ₅ SO ₂ ) ₂ N ^- ), etc.

It is preferred that the ionic compound containing an acrylonitrile group is copolymerized in the copolymer in an amount of from 0.1 to 5.0% by weight.

Specific examples of the antistatic agent are not particularly limited, but specific examples of the ionic compound having a melting point of 25 to 50 ° C include 1-octylpyridinium hexafluorophosphate and 1-decylpyridinium hexafluorophosphate. Salt, 2-methyl-1-dodecylpyridinium hexafluorophosphate, 1-octylpyridinium dodecylbenzenesulfonate, 1-dodecylpyridinium thiocyanate, 1- Dodecylpyridinium dodecylbenzenesulfonate, 4-methyl-1-octylpyridinium hexafluorophosphate, quaternary ammonium salt of trifluoromethanesulfonic acid, and the like. Further, as a specific example of the ionic compound containing an acryloyl group, methyl dimethylamino (meth) acrylate hexafluorophosphate methyl salt [(CH ₃ ) ₃ N ⁺ CH ₂ OCOCQ=CH ₂ ‧ PF ₆ ^- , wherein, Q = H or CH ₃ ], dimethylamino (meth) acrylate bis(trifluoromethanesulfonyl) quinone 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], dimethylaminoethyl methacrylate bis (acyl-fluoro-sulfo) methyl acyl imide salt [(CH ₃ ) ₃ N ⁺ CH ₂ OCOCQ=CH ₂ ‧(FSO ₂ ) ₂ N ^- , wherein Q=H or CH ₃ ].

The above polyether-modified siloxane compound is a siloxane compound having a polyether group, and has a polyoxyl group-containing siloxane unit in addition to a usual siloxane 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 groups 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 ( End base). The polyether group may include: polyoxyethylene _{((C 2 H 4 O)} n) or a polyoxypropylene group _{((C 3 H 6 O)} n) like polyoxyalkylene.

Preferably, the polyether modified siloxane compound is a polycondensation having an HLB value of 7 to 15. Ether modified oxoxane compound. Further, it is preferred that the content of the polyether-modified siloxane compound is 0.01 to 1.0 part by weight based on 100 parts by weight of the copolymer. More preferably, it is 0.1 to 0.5 part by weight.

HLB is a predetermined hydrophilic-lipophilic balance (ratio of hydrophilicity to lipophilicity) such as JIS K3211 (surfactant term).

The above polyether-modified oxoxane compound can be obtained, for example, by grafting an organic compound having an unsaturated bond and a polyoxyalkylene group to a polyorganosiloxane having a decyl group by a hydrogenation oximation reaction. The main chain is obtained. Specifically, a dimethyl methoxy oxane-methyl (polyoxyethylene) decane copolymer, dimethyl methoxy oxane-methyl (polyoxyethylene) decane-methyl (poly) A propylene oxide) siloxane copolymer, a dimethyl methoxy oxane-methyl (polyoxypropylene) siloxane copolymer, or the like.

By blending the above polyether-modified siloxane compound into the binder composition, the adhesion and reworkability of the binder can be improved. When the binder composition does not contain a polyether modified siloxane compound, the cost can be made lower.

As the aforementioned antioxidant, there may be mentioned hindered phenol antioxidants Agent, polyphenol compound, tocopherol compound, and the like. Among them, a tocopherol compound is preferred. Tocopherols are usually vitamin E and are also derived from natural chemicals. As a result, the adverse effects on the human body are small, the safety in use is high, and there is no pollution to the environment. Further, since it is oil-soluble and liquid at normal temperature, it is also excellent in compatibility with the binder composition and precipitation resistance. By formulating the tocopherol compound as the antioxidant, the storage stability of the binder is improved, and thus the pot life of the binder composition in which the curing agent is formulated is increased.

As a tocopherol compound used in the present invention, it is formulated from a binder combination From the viewpoint of use (not to be metabolized as in the human body), it is preferred that the phenolic hydroxyl group of the tocopherol is not converted into an ester or the like and contains a phenolic hydroxyl group. For example, tocopherol and tocotrienol can be mentioned. It is known that a natural type compound (d-body), a non-natural type compound (1-body), and an isomer (dl-body) of an equal mixture thereof are present in tocopherol and tocotrienol. Since the natural compound (d-body) and the racemate (dl-body) are also used as food additives or the like, they are preferred.

Specific examples of the tocopherol compound include d- α -tocopherol, dl- α -tocopherol, d- β -tocopherol, dl- β -tocopherol, and d- γ -tocopherol. Dl- γ -tocopherol, d- δ -tocopherol, dl- δ -tocopherol, d- α -tocotrienol, dl- α -tocotrienol, d- β -tocotrienol, dl- At least at least one of a group consisting of β -tocotrienol, d- γ -tocotrienol, dl- γ -tocotrienol, d- δ -tocotrienol, and dl- δ -tocotrienol One. It is also possible to use two or more tocopherol compounds in combination. As a food additive, it is called "mixed tocopherol", which is based on d- α -tocopherol, d- β -tocopherol, d- γ -tocopherol and d- δ -tocopherol. a mixture called "tocotrienol", which is d- α -tocotrienol, d- β -tocotrienol, d- γ -tocotrienol, and d- δ -fertility A mixture of phenols as a main component.

When the binder 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.

Further, as other components, an alkylene oxide-containing compound can be appropriately formulated. (alkylene oxide) copolymerizable (meth)acrylic monomer, (meth)acrylamide monomer, dialkyl substituted acrylamide monomer, surfactant, curing reminder Conventional additives such as chemicals, plasticizers, fillers, curing inhibitors, processing aids, anti-aging agents, antioxidants, and the like. These may be used alone or in combination of two or more.

a copolymer as a main component used in the binder composition of the present invention, Copolymerization of at least one of (A) alkyl groups having a C4 to C18 (meth) acrylate monomer and (B) a hydroxyl group-containing copolymerizable monomer as a copolymerizable monomer group To synthesize. 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.

Further, the copolymer may preferably contain at least one of a carboxyl group-containing monomer and a hydroxyl group-free and nitrogen-containing vinyl monomer as the other copolymerizable monomer group.

The binder composition of the present invention can be prepared by blending (C) a difunctional or higher isocyanate compound, (D) a metal chelate crosslinking catalyst, and (E) a keto-enol tautomer compound in the above copolymer. And any suitable additives for formulation.

Preferably, the aforementioned copolymer is an acrylic polymer, preferably containing 50 ~100% by weight of (meth) acrylate monomer or acrylic monomer such as (meth)acrylic acid or (meth) acrylamide.

Further, the copolymer preferably has an acid value of 8.0 or less, more preferably 0.01 to 8.0. Thereby, it is possible to improve the contamination and improve the performance of preventing the occurrence of the sticking phenomenon.

Here, the "acid value" is one of the indexes indicating the acid content, and is expressed by the number of mg of potassium hydroxide required to neutralize 1 g of the carboxyl group-containing polymer.

Preferably, the adhesive layer is obtained by crosslinking the above-mentioned binder composition The bonding force at a low peeling speed of 0.3 m/min is 0.05 to 0.2 N/25 mm, and the bonding force at a high peeling speed of 30 m/min is 2.0 N/25 mm or less. Thereby, it is possible to obtain a performance in which the change in the adhesive force with the peeling speed is small, and it is possible to quickly peel off even in the case of high-speed peeling. Further, even if the surface protective film is temporarily peeled off for re-adhesion, it does not require excessive force and is easily peeled off from the adherend.

Preferably, the bonding of the cement composition of the present invention is achieved by crosslinking The gel fraction of the agent layer (crosslinked binder) is 90 to 100%. Since the gel fraction is so high, the bonding force does not become excessive at a low peeling speed, and the phenomenon of eluting unpolymerized monomers or oligomers from the copolymer is lowered, thereby improving reworkability, high temperature/high Durability under wet and inhibit contamination by adherends.

The adhesive film of the present invention is formed on one side or both sides of the resin film. The layer of the binder is formed by crosslinking the binder composition of the present invention. Further, the surface protective film of the present invention is formed by forming a binder layer on one side of a resin film, and the binder layer is obtained by crosslinking the binder composition of the present invention. Since the binder composition of the present invention is formulated with the above components (A) to (E) in a good balance, the storage period is long and the crosslinking speed is high without using an organotin compound. Also fast. Therefore, the surface protective film of the present invention can be suitably used as a surface protective film for a polarizing plate, or can be selected as a precision electric material selected from a flexible printed circuit board, a rigid printed circuit board, and a transparent conductive film. The surface protective film of any of the precision electrical/electronic parts in the electronic component group is suitable for use.

In the adhesive film and surface protection film of the present invention, as a resin film or A polyester film or the like can be used as the substrate of the release film (separator) for protecting the adhesive layer.

In addition, for the resin film, a layer of the adhesive film may be formed on the resin film. Anti-fouling treatment by an anthrone or a fluorine-based release agent, a coating agent, cerium oxide fine particles or the like is performed on the opposite side surface, and antistatic treatment by application or mixing of an antistatic agent can be performed. .

In addition, the release film is subjected to a release treatment by a release agent such as an anthrone or a fluorine-based agent on the surface on the side where the bonding surface of the adhesive layer is bonded.

[Examples]

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

<Manufacture 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 tube, thereby replacing the air in the reaction apparatus with nitrogen. Then, 100 parts by weight of 2-ethylhexyl acrylate and 3.5 parts by weight of 8-hydroxyoctyl acrylate were placed in the reaction apparatus. Then, 0.1 part by weight of azobisisobutyronitrile as a polymerization initiator was added dropwise thereto over 2 hours, and the mixture was reacted at 65 ° C for 6 hours to obtain an acrylic acid used in 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 described in (A), (B), and (I) in Table 1, the operation was carried out in the same manner as in the above-described acrylic copolymer solution 1 used in Example 1, and obtained. The acrylic copolymer solutions used in Examples 2 to 6 and Comparative Examples 1 to 3 were used.

<Manufacture of a binder composition and a surface protective film> [Example 1]

To the acrylic copolymer solution 1 of Example 1 produced as described above, 6.0 parts by weight of acetamidine acetone was added and stirred, and then 1.5 parts by weight of Coronate HX ( HX, an isocyanurate of a hexamethylene diisocyanate compound, and 0.05 part by weight of tris(2,4-pentanedione)iron (III) were stirred and mixed to obtain a binder composition of Example 1. The adhesive composition was applied onto a release film composed of a polyethylene terephthalate (PET) film coated with an fluorenone resin, and then dried at 90 ° C to remove the solvent to obtain a binder layer. A bonded sheet having a thickness of 25 μm.

Then, a polyethylene terephthalate (PET) film having antistatic treatment and antifouling treatment is prepared on one side, and the bonded sheet is transferred to the polyethylene terephthalate (PET). On the surface opposite to the surface on which the antistatic treatment and the antifouling treatment were carried out, a PET film/adhesive layer/release film (PET coated with an anthrone resin) having antistatic treatment and antifouling treatment was obtained. The surface protective film of Example 1 in which the film was laminated.

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

Surface protection of Examples 2 to 6 and Comparative 1 to 3 was obtained in the same manner as in the surface protective film of Example 1 except that the composition of each additive was set as described in (C) to (E) of Table 1. membrane.

In Table 1, the numerical values in parentheses indicate the numerical values of the parts by weight obtained by setting the total weight of the group (A) to 100 parts by weight. In addition, the ratio of (E) / (D) is shown in Table 2. Further, the names of the compounds corresponding to the abbreviations of the respective components used in Table 1 are shown in Table 3. In addition, Coronate (registered trademark) HX, Coronate HL and Coronate L are trade names of Nippon Polyurethane Industry Co., Ltd.; Takenate (registered trademark) D-140N is Mitsui Chemicals Co., Ltd. Trade name; DURANATE (registered trademark) D101 is the trade name of Asahi Kasei Chemicals Corporation.

<Test method and evaluation>

After the surface protective films of Examples 1 to 6 and Comparative Examples 1 to 3 were aged for 7 days in an environment of 23 ° C and 50% RH, the release film (PET film coated with an anthrone resin) was peeled off to bond The agent layer is exposed. Further, the surface protective film exposed to the adhesive layer is bonded to the surface of the polarizing plate adhered to the liquid crystal cell through the adhesive layer, and left for 1 day, and then subjected to autoclave treatment at 50 ° C and 5 atm for 20 minutes, further. The surface protective film thus obtained was used as a sample for measuring the adhesion force by allowing to stand at room temperature for 12 hours.

<bonding force>

Using a tensile tester, the above-obtained measurement sample was peeled off at a low peeling speed (0.3 m/min) and a high peeling speed (30 m/min) in a 180° direction (a 25 mm wide surface protective film was attached to the polarized light). The sample formed on the surface of the plate was measured for peel strength, and the peel strength was used as a bonding force.

<Storage period>

Immediately after the addition of the additives of (C) to (E), the viscosity η ₀ (initial viscosity) of the binder composition was measured, and then the viscosity of the binder composition was measured after placing the binder composition at 23 ° C × 8 hours in a sealed state. η ₁ (viscosity after 8 hours). As an index of the storage period, the ratio of η ₁ when η ₀ is 1.0, that is, the ratio of η ₁ /η ₀ is obtained. The evaluation target is as follows: when the viscosity after 8 hours is lower than 1.25 times the initial viscosity, it is evaluated as "○", and when it is 1.25 times or more and less than 1.50 times, it is evaluated as "△", and it is placed at 1.50 times or more or after 8 hours. When gelation occurred, it was evaluated as "x".

The evaluation results are shown in Table 4.

For the surface protective films of Examples 1 to 6, at a low peeling speed The bonding force at 0.3 m/min is 0.05 to 0.2 N/25 mm, and the bonding force at a high peeling speed of 30 m/min is 2.0 N/25 mm or less, and the storage period is also long enough.

That is, the balance of the adhesive force is excellent at a low peeling speed and a high peeling speed, and the storage period is long, and the characteristics as the surface protective film are also excellent.

Further, in the surface protective films of Examples 1 to 6, since the binder composition does not contain an organotin compound, it is highly safe.

For the surface protective film of Comparative Example 1, it may be due to no There is a (C) difunctional or higher isocyanate compound as a crosslinking agent, and the binding force at a low peeling speed of 0.3 m/min and a high peeling speed of 30 m/min is excessive.

In the surface protective film of Comparative Example 2, since the ratio of the (E) keto-enol tautomer compound to the crosslinking catalyst of the (D) metal chelate compound was small, the storage period was short.

The surface protective film of Comparative Example 3 may have a storage period of too short due to a small ratio of the (E) keto-enol tautomer compound to the crosslinking catalyst of the (D) metal chelate compound. Since crosslinking has been carried out before coating, coating cannot be performed.

As described above, in the surface protective films of Comparative Examples 1 to 3, it was not possible to simultaneously satisfy all the performance requirements such as excellent balance of the adhesive strength at a low peeling speed and a high peeling speed, and a long storage period.

Claims (12)

A binder composition in which at least one of C4 to C18 (meth) acrylate monomers having a carbon number of (A) alkyl group and (B) a hydroxyl group-containing group as a copolymerizable monomer group 100 parts by weight of the copolymer of the copolymerizable monomer, containing (C) 0.1 to 10 parts by weight of the difunctional or higher isocyanate compound, (D) 0.001 to 0.5 part by weight of the metal chelate crosslinking catalyst, and (E) keto-enol The tautomeric compound is 0.1 to 300 parts by weight, and the ratio by weight of (E)/(D) is 70 to 1,000. The adhesive composition according to claim 1, wherein the viscosity of the adhesive composition after storage of the above-mentioned binder composition at 23 ° C for 8 hours is lower than that after just after blending 1.25 times the viscosity. The binder composition according to claim 1 or 2, wherein the (B) hydroxyl group-containing copolymerizable monomer is selected from the group consisting of 8-hydroxyoctyl (meth)acrylate, (methyl) ) 6-hydroxyhexyl acrylate, 4-hydroxybutyl (meth) acrylate, 2-hydroxyethyl (meth) acrylate, N-hydroxy (meth) acrylamide, N-methylol (methyl) At least one or more of the compound group consisting of acrylamide and N-hydroxyethyl (meth) acrylamide. The binder composition according to any one of claims 1 to 3, wherein, in the (C) difunctional or higher isocyanate compound, the difunctional isocyanate compound is an acyclic aliphatic isocyanate compound and is A compound formed by reacting a diisocyanate compound with a diol compound, wherein the diisocyanate compound is an aliphatic diisocyanate selected from the group consisting of tetramethylene diisocyanate, pentamethylene diisocyanate, and hexamethylene diene. One of a group consisting of isocyanate, trimethylhexamethylene diisocyanate and lysine diisocyanate selected from 2-methyl1,3-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 One of a group of compounds consisting of pentanediol, 2,2-dimethyl-1,3-propanediol monohydroxypivalate, polyethylene glycol, and polypropylene glycol, and the trifunctional isocyanate compound is hexamethylene Isocyanurate of diisocyanate compound, isocyanurate of isophorone diisocyanate compound, adduct of hexamethylene diisocyanate compound, adduct of isophorone diisocyanate compound, Liu Ya Biuret of methyl diisocyanate compound, biuret of isophorone diisocyanate compound, isocyanurate of toluene diisocyanate compound, isocyanurate of benzene dimethylene diisocyanate compound, hydrogenated benzene An isocyanurate of a methyl diisocyanate compound, an adduct of a toluene diisocyanate compound, a phthalic acid Diisocyanate adduct compound, adducts of hydrogenated xylylene diisocyanate compound. The binder composition according to claim 1, wherein in the binder composition, the crosslinking catalyst does not contain an organotin compound. The binder composition according to any one of claims 1 to 5, wherein the copolymer is a group of other copolymerizable monomers including a carboxyl group-containing monomer, a hydroxyl group-free nitrogen group-containing vinyl group. At least one or more acrylic polymers in the monomer. The binder composition according to any one of claims 1 to 6, Wherein, the gel fraction of the binder composition after crosslinking is 90 to 100%. The adhesive composition according to any one of claims 1 to 7, wherein the adhesive layer obtained by crosslinking the adhesive composition has a low peeling speed of 0.3 m/min. 0.05~0.2N/25mm, the bonding force at a high peeling speed of 30m/min is 2.0N/25mm or less. A bonded film obtained by forming a binder layer on one or both sides of a resin film, the binder layer being crosslinked by the binder composition according to any one of claims 1 to 8. Made. A surface protective film obtained by forming a binder layer on one side of a resin film, the binder layer being obtained by crosslinking the binder composition according to any one of claims 1 to 9. . The surface protective film according to claim 10, which is used as a surface protective film for a polarizing plate. The surface protective film according to claim 10, which is used as a surface protective film for precision electric/electronic parts selected from a flexible printed circuit board and rigidly printed. Any of a group of precision electrical/electronic components composed of a circuit board and a transparent conductive film.