KR20220013499A - Adhesive composition - Google Patents

Abstract

Provided are an adhesive composition, an adhesive film using the same, and a surface protection film. In terms of a low peel rate and a high peel rate, the present invention can achieve both anti-static performance and stain resistance performance along with excellent adhesive performance such as having a well-balanced adhesive force. An antistatic agent (F) is an ionic compound having a melting point of 25-80℃ represented by a chemical formula, K^+ x A^-, and is contained in a ratio of 0.01-10 parts by weight with respect to 100 parts by weight of an acrylic polymer. K^＋is one kind of positive ions selected from the group consisting of pyridinium, imidazolium, phosphonium, sulfonium, pyrrolidinium, guanidinium, ammonium, isouronium, thiouronium, piperidinium, pyrazolium, methylium, and morpholinium, and A^- is one kind of negative ions selected from the group consisting of trifluoromethanesulfonate and pentafluoroethanesulfonate which do not contain an imide group.

Description

Adhesive composition {ADHESIVE COMPOSITION}

The present invention relates to a pressure-sensitive adhesive composition containing an antistatic agent, an adhesive film using the same, and a surface protection film. More specifically, in a low-speed peeling rate and a high-speed peeling rate, an adhesive composition capable of achieving both antistatic performance and stain resistance performance as well as excellent adhesive performance, such as having a well-balanced adhesive force, and an adhesive film using the same; It relates to providing a surface protection film.

Conventionally, in the manufacturing process of optical members, such as a polarizing plate which is a member which comprises a liquid crystal display, the surface protection film for protecting the surface of an optical member temporarily is pasted together. Such a surface protection film is used only in the process of manufacturing an optical member, and is peeled and removed from an optical member at the time of mounting an optical member to a liquid crystal display. Since the surface protection film for protecting the surface of such an optical member is used only in the manufacturing process of an optical member, generally it may call a process film.

Thus, the surface protection film used in the process of manufacturing an optical member has an adhesive layer formed in one side of the polyethylene terephthalate (PET) resin film which has optical transparency. In order to protect the adhesive layer until a surface protection film is bonded together to an optical member, the release film by which the release process was carried out is bonded together by the surface of an adhesive layer.

And optical members, such as a polarizing plate, receive the product inspection accompanying optical evaluation, such as the display ability of a liquid crystal display board, hue, contrast, and foreign material mixing in the state to which the surface protection film was pasted up. For this reason, as a required performance for a surface protection film, that which does not adhere to a bubble, a foreign material, and the low molecular-weight component of an adhesive composition to an adhesive layer, ie, it is calculated|required that it has stain-resistance performance.

In addition, when peeling the surface protection film from an optical member such as a polarizing plate, there is a concern that peeling charging caused by static electricity generated when the pressure-sensitive adhesive layer and the adherend are peeled off affects the failure of the electric control circuit of the liquid crystal display. For this reason, it is calculated|required that the adhesive layer of a surface protection film has the outstanding antistatic performance.

Furthermore, in recent years, as a polarizer protective layer (sometimes referred to as a protective film) of a polarizing plate, in addition to the conventionally used triacetyl cellulose (TAC), acrylic resins such as polymethyl methacrylate (PMMA), polyethylene terephthalate (PET), etc. Adoption of materials which easily generate peeling electrification when peeling off the surface protection film of a polarizing plate, such as polyester-type resin, a cyclic olefin-type polymer, and polycarbonate, is expanding. For this reason, the thing excellent in the antistatic performance calculated|required of the adhesive layer for surface protection films of a polarizing plate compared with the past is required.

Moreover, when finally peeling a surface protection film from optical members, such as a polarizing plate, being able to peel quickly is calculated|required. It is calculated|required that there are few changes in adhesive force with a peeling rate so that what is called a high-speed peeling may also peel quickly.

As such, in recent years, with respect to the pressure-sensitive adhesive layer constituting the surface protection film, (1) having a balance of adhesive force in a low-speed peeling rate and a high-speed peeling rate, (2) having a stain resistance performance, (3) excellent charging What has prevention performance, etc. are calculated|required from the point of the ease of use in using a surface protection film.

However, with respect to the performance required for the pressure-sensitive adhesive layer constituting the surface protection film, (1) required for the pressure-sensitive adhesive layer of the surface protection film even if each of the performance requirements (1) to (3) can be satisfied. It was a very difficult subject to satisfy all the required performance of -(3) at the same time.

In order to solve these problems, for example, (1) having a balance of adhesive force in a low-speed peeling rate and a high-speed peeling rate, (2) having a stain resistance performance, (3) having an excellent antistatic performance For each, the following proposals are known.

(1) Regarding to have a balance of adhesive force in the low-speed peeling rate and the high-speed peeling rate, the main component is a copolymer of (meth)acrylic acid alkylester having an alkyl group having 7 or less carbon atoms and a carboxyl group-containing copolymerizable compound, and this is a crosslinking agent In an acrylic pressure-sensitive adhesive layer formed by crosslinking with a furnace, there was a problem in that, when adhered for a long period of time, the pressure-sensitive adhesive moved to the adherend side, and the synergism of the adhesive force to the adherend was large over time. In order to avoid this, it is known that a copolymer of a (meth)acrylic acid alkylester having an alkyl group having 8 to 10 carbon atoms and a copolymerizable compound having an alcoholic hydroxyl group is used, and an adhesive layer crosslinked with a crosslinking agent is formed ( Patent Document 1).

In addition, a small amount of a copolymer of a (meth)acrylic acid alkylester and a carboxyl group-containing copolymerizable compound is blended in the same copolymer as described above, and a pressure-sensitive adhesive layer obtained by crosslinking this with a crosslinking agent is proposed. However, when they are used for surface protection such as plastic plates with a smooth surface due to their low surface tension, there is a problem in that they cause peeling phenomena such as lifting due to heating during processing or storage, or when peeling at high speed in the manual operation area. There also existed a problem that peelability was inferior.

In order to solve these problems, a) 100 parts by weight of (meth)acrylic acid alkyl ester containing (meth)acrylic acid alkyl ester having an alkyl group having 8 to 10 carbon atoms as a main component, b) 1 to 15 weight part of carboxyl group-containing copolymerizable compound Part and c) a copolymer of a monomer mixture formed by adding 3 to 100 parts by weight of a vinyl ester of an aliphatic carboxylic acid having 1 to 5 carbon atoms, and a crosslinking agent equivalent to or more than the carboxyl group of the component b) is blended. It has been proposed (Patent Document 2).

In the pressure-sensitive adhesive composition described in Patent Document 2, peeling phenomena such as lifting during processing or storage do not occur, and the increase in adhesive strength over time is small and excellent in re-peelability, and long-term storage, especially long-term storage under a high-temperature atmosphere It is said that it can peel again with a small force, and does not generate|occur|produce an adhesive residue on a to-be-adhered body at that time, and also when high-speed peeling is performed, it is said that it can peel again with a small force.

However, in the adhesive composition of patent document 2, since the gel fraction of the adhesive layer in Examples 1-3 is 90 %, an unpolymerized monomer or an oligomer elutes easily from a copolymer. In addition, there is no description regarding antistatic performance and stain resistance performance in Patent Document 2, and when a material that is prone to peeling and charging is used as an adherend, it is difficult to obtain a pressure-sensitive adhesive layer having excellent antistatic performance and stain resistance performance. there was.

Further, (2) for those having stain resistance performance, 0 parts by mass or more and less than 0.5 parts by mass of a carboxyl group-containing monomer, 0.6 to 9 parts by mass of a hydroxyl group-containing (meth)acrylic monomer, and 99.4 to 90.5 parts by mass of a (meth)acrylic acid ester monomer. 100 parts by mass of a (meth)acrylic copolymer having a weight average molecular weight of 100,000 or more and less than 1,000,000; And a pressure-sensitive adhesive composition containing 0.1 to 5 parts by mass of a carbodiimide-based crosslinking agent is disclosed (Patent Document 3).

The pressure-sensitive adhesive composition described in Patent Document 3 is characterized in that a carbodiimide-based crosslinking agent is used as a crosslinking agent for a (meth)acrylic copolymer having a specific composition. For this reason, the crosslinked structure which can follow the shrinkage|contraction by the pressure and temperature at the time of an autoclave process can be formed in an adhesive layer. For this reason, the pressure-sensitive adhesive layer formed using the pressure-sensitive adhesive composition described in Patent Document 3 can suppress and prevent foaming even under high-temperature and high-pressure conditions (in autoclave treatment), and has excellent stain-resistance performance and excellent transparency. has been

However, in the pressure-sensitive adhesive composition described in Patent Document 3, although the stain resistance performance is improved, it has not been realized to achieve both the excellent adhesion performance and the antistatic performance, and it remains as a problem to be further solved.

Moreover, (3) About what has the outstanding antistatic performance, the method of mixing an antistatic agent into a base film, etc. are known as a method for providing antistatic property to a surface protection film. Examples of the antistatic agent include (a) quaternary ammonium salts, pyridinium salts, and various cationic antistatic agents having a cationic group such as a primary to tertiary amino group, (b) a sulfonate group, a sulfate group, phosphoric acid Anionic antistatic agents having anionic groups such as ester bases and phosphonate groups, (c) amphoteric antistatic agents such as amino acids and aminosulfate esters, (d) aminoalcohols, glycerin, polyethylene glycol, etc. An on-type antistatic agent, (e) a high molecular weight antistatic agent as described above, etc. are disclosed (patent document 4).

However, in the surface protection film described in Patent Document 4, although there is a description regarding the provision of antistatic performance related to the adhesion of foreign substances to the adherend, there is no description of a means for reconciling stain resistance performance with excellent adhesion performance. remains as a challenge to be addressed.

Moreover, in recent years, making a base film contain an antistatic agent, or making an adhesive layer contain an antistatic agent directly without apply|coating to the surface of a base film is proposed. For example, an antistatic pressure-sensitive adhesive composition is disclosed in which a salt having an anion having a fluoro group and a sulfonyl group is dispersed in a dissolved state in a polyether ester plasticizer containing a polyether group in the main chain. (Patent Document 5).

In the pressure-sensitive adhesive composition described in Patent Document 5, as a plasticizer, an ester formed of a mono or dicarboxylic acid having a saturated or unsaturated acyclic hydrocarbon group and an alcohol having an acyclic hydrocarbon group having 1 to 20 carbon atoms, or in the unsaturated acyclic hydrocarbon group The use of plasticizers comprising esters in which the unsaturated groups are epoxidized is disclosed. The mono- or dicarboxylic acid having such a saturated or unsaturated acyclic hydrocarbon group has a carbon number close to the carbon number of the acrylic monomer constituting the acrylic copolymer used in the pressure-sensitive adhesive layer, thereby improving compatibility in the antistatic pressure-sensitive adhesive composition, Plasticizer Since a plasticizer is preferably hold|maintained in an acrylic type antistatic adhesive composition, it is said that bleed-out is suppressed.

However, in the antistatic pressure-sensitive adhesive composition described in Patent Document 5, although there is a disclosure of a technology for improving antistatic performance and bleed-out, excellent adhesion performance such as balance of adhesive force in low-speed peeling rates and high-speed peeling rates is obtained. There is no such thing, and the subject of obtaining the adhesive composition which has the outstanding adhesive performance remains.

Japanese Laid-Open Patent Publication No. 63-225677 Japanese Patent Laid-Open No. 11-256111 Japanese Patent Laid-Open No. 2011-122054 Japanese Patent Laid-Open No. 11-070629 Japanese Patent Laid-Open No. 2014-118469

As described above, with respect to the pressure-sensitive adhesive layer constituting the surface protection film, (1) having a balance of adhesive strength in low-speed peeling rate and high-speed peeling rate, (2) having stain resistance performance, (3) excellent antistatic No prior art can be found that simultaneously solves having performance.

In addition, in the conventional pressure-sensitive adhesive layer formed using the pressure-sensitive adhesive composition having antistatic performance and the surface protection film using the same, the antistatic performance and the stain resistance performance to the adherend are in a trade-off relationship, and the antistatic performance is It was difficult to improve the stain resistance performance while maintaining it.

Furthermore, in recent years, the type of adherend material to which the surface protection film is bonded has increased, and since the surface treatment of the adherend is also applied in various fields, it is more difficult to simultaneously express stain resistance and antistatic performance for all adherends. is losing

The present invention has been made in view of the above circumstances, and it is possible to achieve both antistatic performance and stain resistance performance as well as excellent adhesion performance such as having a balanced adhesive force in a low-speed peeling rate and a high-speed peeling rate, and an adhesive composition and It makes it a subject to provide the adhesion film and surface protection film using the same.

The inventors of the present invention, as an antistatic agent, a pressure-sensitive adhesive composition containing an ionic compound that is solid at room temperature having a trifluoromethanesulfonate anion or a pentafluoroethanesulfonate anion having a melting point of 25 to 80° C. It has been found that antistatic performance and antifouling performance can be exhibited at the same time, and the present invention has been completed.

As an antistatic agent of the present invention, pyridinium, imidazolium, phosphonium, sulfonium, pyrrolidinium, guanidinium, ammonium, isouronium, thiouronium, piperidinium, pyrazolium having a melting point of 25 to 80°C A pressure-sensitive adhesive composition containing an ionic compound which is solid at room temperature having one cation selected from the group consisting of , methylium and morpholinium, and a trifluoromethanesulfonate anion or a pentafluoroethanesulfonate anion, and An adhesive film and a surface protection film can realize both antistatic performance and stain resistance performance together with excellent adhesive performance, and solve the problems of the prior art.

In order to solve the above problems, the present invention provides a pressure-sensitive adhesive composition comprising an acrylic polymer, (F) an antistatic agent, and (C) a crosslinking agent, wherein the (F) antistatic agent has a melting point of 25 to 80 represented by the following formula (1) It is an ionic compound at ℃,

K ⁺ A ^- (1)

[In formula (1), K ⁺ is pyridinium, imidazolium, phosphonium, sulfonium, pyrrolidinium, guanidinium, ammonium, isouronium, thiouronium, piperidinium, pyrazolium, methylium , is one kind of cation selected from the group consisting of morpholinium, and A ^- is one kind of anion selected from the group consisting of trifluoromethanesulfonate anion and pentafluoroethanesulfonate anion not containing an imide group ]

The acrylic polymer is an acrylic polymer having a glass transition point temperature of 0° C. or less, and the ionic compound is contained as an essential component in a ratio of 0.01 to 10 parts by weight based on 100 parts by weight of the acrylic polymer. to provide.

(B-1) At least one type of copolymerizable vinyl monomer containing a hydroxyl group with respect to a total of 100 parts by weight of at least one or more types of (meth)acrylic acid ester monomers having C1 to C18 alkyl group in the acrylic polymer (A) The total is 0.01 to 10 parts by weight, and/or (B-2) an acrylic polymer of a copolymer copolymerized in a ratio of 0.01 to 0.5 parts by weight of the sum of at least one type of copolymerizable vinyl monomer containing a carboxyl group, A) Isooctyl (meth) acrylate, isononyl (meth) acrylate, 2-ethylhexyl (meth) acryl in a total of 100 parts by weight of at least one or more types of (meth)acrylic acid ester monomers having C1 to C18 alkyl group It is made by containing at least one selected from the group consisting of lattice in a ratio of 50 parts by weight or more, and 0.1 to 10 parts by weight of the trifunctional or higher isocyanate compound as the crosslinking agent (C) with respect to 100 parts by weight of the acrylic polymer. It is preferable that the pressure-sensitive adhesive composition further contains (D) a crosslinking accelerator for a metal chelate compound and (E) a ketoenol tautomer compound.

The surface resistivity of the pressure-sensitive adhesive layer crosslinked with the pressure-sensitive adhesive composition is 1.0×10 ⁺¹² Ω/□ or less, and a resin composition for forming a low refractive index layer containing a fluorine compound on the surface of the PMMA substrate or the TAC substrate of the pressure-sensitive adhesive layer is formed using The peel electrification voltage for the low refractive index layer and the peel electrification voltage for the plane layer on which the surface of the PMMA substrate or TAC substrate is not treated are all ±0.3 kV or less, and the pressure-sensitive adhesive layer is laminated with a protective layer on the polarizer After bonding to an adherend, which is a polarizing plate whose surface has been treated with a low-reflection surface-treated composition with a composition containing a fluorine compound, the surface of the protective layer is left to stand for 48 hours under an atmosphere of a temperature of 60° C. and a humidity of 90% RH, taken out from the atmosphere and 1 day after The stain resistance performance is "no staining" with respect to the surface of the adherend, and the adhesive force of the pressure-sensitive adhesive layer to the low refractive index layer applied to the surface of the PMMA substrate is 0.04 at a low peel rate of 0.3 m/min. It is -0.2 N/25 mm, and it is preferable that the adhesive force in high-speed peeling speed 30 m/min is 2.0 N/25 mm or less.

(B-1) The copolymerizable vinyl monomer containing a hydroxyl group is 8-hydroxyoctyl (meth) acrylate, 6-hydroxyhexyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, 2- At least one selected from the group consisting of hydroxyethyl (meth) acrylate, N-hydroxy (meth) acrylamide, N-hydroxymethyl (meth) acrylamide, and N-hydroxyethyl (meth) acrylamide ego,

(B-2) the copolymerizable vinyl monomer containing a carboxyl group is (meth)acrylic acid, carboxyethyl (meth)acrylate, carboxypentyl (meth)acrylate, 2- (meth)acryloyloxyethylhexahydrophthalic acid, 2-(meth)acryloyloxypropylhexahydrophthalic acid, 2-(meth)acryloyloxyethylphthalic acid, 2-(meth)acryloyloxyethyl succinic acid, 2-(meth)acryloyloxyethyl maleic acid , carboxypolycaprolactone mono(meth)acrylate, and 2-(meth)acryloyloxyethyltetrahydrophthalic acid are preferably at least one selected from the group consisting of compounds.

In the pressure-sensitive adhesive composition, based on 100 parts by weight of the acrylic polymer, 0.001 to 0.5 parts by weight of the (D) metal chelate compound crosslinking accelerator and (E) 0.1 to 300 parts by weight of the ketoenol tautomer compound (D) the crosslinking accelerator of the metal chelate compound is at least one selected from the group consisting of an aluminum chelate compound, a titanium chelate compound, and an iron chelate compound, and (E) / part by weight of (D) It is preferable that the ratio is 70-1000.

In addition, the present invention provides a pressure-sensitive adhesive film, characterized in that the pressure-sensitive adhesive layer crosslinked the pressure-sensitive adhesive composition is laminated on one side of the resin film.

In addition, the present invention provides a surface protection film using the adhesive film.

In addition, the present invention provides a surface protection film for a polarizing plate in which the adhesive film is used.

In addition, the present invention provides an optical film having a pressure-sensitive adhesive layer formed on at least one side of the optical film, in which the pressure-sensitive adhesive layer obtained by crosslinking the pressure-sensitive adhesive composition is laminated.

Furthermore, this invention provides the adhesive film by which the antistatic treatment and antifouling|stain-resistant process are given to the surface opposite to the side on which the said adhesive layer was formed of one side of the said resin film.

The pressure-sensitive adhesive composition according to the present invention has excellent adhesion performance and does not deteriorate over time, and has excellent antistatic peeling performance compared to the conventional pressure-sensitive adhesive composition for a surface protection film.

In particular, the surface protection film according to the present invention is a low-refractive-index layer formed by using an antifouling layer containing a fluorine compound, or a composition for forming a low-refractive-index layer containing a fluorine compound, in which the adherend is laminated on the surface of the optical film. , compared to the surface protection film according to the prior art, has excellent adhesion performance and does not deteriorate over time, has excellent peeling antistatic performance, and has a remarkable effect in coexistence of antistatic performance and stain resistance performance.

That is, since the pressure-sensitive adhesive composition according to the present invention and the surface protection film using the same have excellent adhesive performance, do not deteriorate over time, and have excellent peeling and antistatic performance, industrial use value is very high.

EMBODIMENT OF THE INVENTION Hereinafter, this invention is demonstrated based on preferable embodiment.

The pressure-sensitive adhesive composition of the present embodiment is an acrylic polymer, (F) antistatic agent, and (C) a pressure-sensitive adhesive composition containing a crosslinking agent, wherein the (F) antistatic agent is an ion having a melting point of 25 to 80 ° C. represented by the following formula (1) is a sex compound,

K ⁺ A ^- (1)

[In formula (1), K ⁺ is pyridinium, imidazolium, phosphonium, sulfonium, pyrrolidinium, guanidinium, ammonium, isouronium, thiouronium, piperidinium, pyrazolium, methylium , is one kind of cation selected from the group consisting of morpholinium, and A ^- is one kind of anion selected from the group consisting of trifluoromethanesulfonate anion and pentafluoroethanesulfonate anion not containing an imide group ]

The acrylic polymer is an acrylic polymer having a glass transition point temperature of 0° C. or less, and the ionic compound is contained as an essential component in an amount of 0.01 to 10 parts by weight based on 100 parts by weight of the acrylic polymer.

The acrylic polymer used for the adhesive composition of this embodiment is a main polymer of an adhesive composition, and is an acrylic polymer whose glass transition point temperature is 0 degrees C or less. Further, the acrylic polymer is preferably (A) a copolymer containing, as a main component, a (meth)acrylic acid ester monomer having C1 to C18 carbon atoms in the alkyl group.

(A) As the (meth)acrylic acid ester monomer having C1 to C18 alkyl group, methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, butyl (meth)acrylate, isobutyl ( Meth) acrylate, pentyl (meth) acrylate, hexyl (meth) acrylate, heptyl (meth) acrylate, octyl (meth) acrylate, isooctyl (meth) acrylate, 2-ethylhexyl (meth) acrylate , nonyl (meth) acrylate, isononyl (meth) acrylate, decyl (meth) acrylate, undecyl (meth) acrylate, dodecyl (meth) acrylate, tridecyl (meth) acrylate, tetradecyl ( Meth) acrylate, pentadecyl (meth) acrylate, hexadecyl (meth) acrylate, heptadecyl (meth) acrylate, octadecyl (meth) acrylate, cyclopentyl (meth) acrylate, cyclohexyl (meth) Acrylates etc. are mentioned. The alkyl group of the alkyl (meth)acrylate monomer may be linear, branched or cyclic.

The acrylic polymer used in the pressure-sensitive adhesive composition of the present embodiment is (A) isooctyl (meth) acrylate, isononyl ( It is preferable to contain at least one selected from the group consisting of meth)acrylate and 2-ethylhexyl (meth)acrylate in a proportion of 50 parts by weight or more, more preferably 60 parts by weight or more, 75 It is especially preferable to contain it in the ratio of weight part or more.

The acrylic polymer used in the pressure-sensitive adhesive composition of the present embodiment is (B-1) at least one type of copolymerizable vinyl monomer containing a hydroxyl group, and/or (B-2) at least one copolymerizable vinyl monomer containing a carboxyl group. It is preferable that it is an acrylic polymer of the copolymer which copolymerized 1 or more types. At least one of (B-1) a copolymerizable vinyl monomer containing a hydroxyl group and a copolymerizable vinyl monomer containing a carboxyl group (B-2) may be copolymerized with the said acrylic polymer, and both may be copolymerized.

(B-1) At least one type of copolymerizable vinyl monomer containing a hydroxyl group with respect to a total of 100 parts by weight of at least one or more types of (meth)acrylic acid ester monomers having C1 to C18 alkyl group in the acrylic polymer (A) It is preferable that the total is 0.01 to 10 parts by weight, and/or (B-2) an acrylic polymer of a copolymer obtained by copolymerizing the total of at least one type of copolymerizable vinyl monomer containing a carboxyl group in a proportion of 0.01 to 0.5 parts by weight. .

(B-1) You may copolymerize the copolymerizable monomer containing a hydroxyl group with the acrylic polymer used for the adhesive composition of this embodiment. (B-1) As a copolymerizable monomer containing a hydroxyl group, 8-hydroxyoctyl (meth)acrylate, 6-hydroxyhexyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, 2- At least one selected from the group consisting of hydroxyethyl (meth) acrylate, N-hydroxy (meth) acrylamide, N-hydroxymethyl (meth) acrylamide, N-hydroxyethyl (meth) acrylamide, and the like more preferably.

(B-1) When copolymerizing a copolymerizable monomer containing a hydroxyl group, (A) with respect to a total of 100 parts by weight of at least one or more of the (meth)acrylic acid ester monomer having C1 to C18 alkyl group (B-1) It is preferably contained in a proportion of 0.01 to 10.0 parts by weight of a copolymerizable monomer containing a hydroxyl group, more preferably contained in a proportion of 0.5 to 7.0 parts by weight, and particularly preferably contained in a proportion of 1.0 to 6.0 parts by weight. do.

You may copolymerize the copolymerizable monomer containing (B-2) a carboxyl group with the acrylic polymer used for the adhesive composition of this embodiment. (B-2) As a copolymerizable monomer containing a carboxyl group, (meth)acrylic acid, carboxyethyl (meth)acrylate, carboxypentyl (meth)acrylate, 2- (meth)acryloyloxyethylhexahydrophthalic acid, 2-(meth)acryloyloxypropylhexahydrophthalic acid, 2-(meth)acryloyloxyethylphthalic acid, 2-(meth)acryloyloxyethyl succinic acid, 2-(meth)acryloyloxyethyl maleic acid , carboxypolycaprolactone mono(meth)acrylate, 2-(meth)acryloyloxyethyltetrahydrophthalic acid, and the like are preferably at least one selected from the group consisting of compounds.

(B-2) When copolymerizing a copolymerizable vinyl monomer containing a carboxyl group, (A) 0.01 to 0.5 weight by weight based on 100 parts by weight of at least one total of at least one C1 to C18 (meth)acrylic acid ester monomer in the alkyl group It is preferable to contain in the ratio of parts, It is more preferable to contain in the ratio of 0.01-0.4 weight part, It is especially preferable to contain in the ratio of 0.01-0.3 weight part.

The manufacturing method of the acrylic polymer contained in the adhesive composition which concerns on this embodiment is not specifically limited, Well-known polymerization methods, such as a solution polymerization method and an emulsion polymerization method, can be used suitably. As for the weight average molecular weight of the copolymer of an acryl-type polymer, 500,000-3 million are mentioned, for example. It is preferable that the acid value of an acrylic polymer is 0.1-1.0. For this reason, stain-resistance performance can be improved. Here, "acid value" is one of the index|indexes which show content of an acid, and is represented by the mg number of potassium hydroxide required to neutralize 1 g of polymer containing a carboxyl group.

The pressure-sensitive adhesive composition according to the present embodiment contains (F) an antistatic agent. The antistatic agent (F) of the present embodiment is an ionic compound having a melting point of 25 to 80°C represented by the following general formula (1).

K ⁺ A ^- (1)

[In formula (1), K ⁺ is pyridinium, imidazolium, phosphonium, sulfonium, pyrrolidinium, guanidinium, ammonium, isouronium, thiouronium, piperidinium, pyrazolium, methylium , is one kind of cation selected from the group consisting of morpholinium, and A ^- is one kind of anion selected from the group consisting of trifluoromethanesulfonate anion and pentafluoroethanesulfonate anion not containing an imide group ]

The ionic compound is preferably a solid at room temperature. The normal temperature is, for example, a temperature of less than 25°C, and specifically, it is preferable that the ionic compound is a solid at 23°C. The pressure-sensitive adhesive composition according to the present embodiment contains the ionic compound as an essential component in an amount of 0.01 to 10 parts by weight with respect to 100 parts by weight of the acrylic polymer.

(F) Specific examples of the antistatic agent include 1-octyl-2-methylpyridinium trifluoromethanesulfonate salt, 1,2,3-trimethylimidazolium pentafluoroethanesulfonate salt, 1-Butyl-2,3-dimethylimidazolium trifluoromethanesulfonate salt, 1-hexyl-4-methylpyridinium pentafluoroethanesulfonate salt, 1-octyl-3-methylpyridinium trifluoromethane A sulfonate salt, n-octylpyridinium trifluoromethanesulfonate salt, etc. are mentioned.

The pressure-sensitive adhesive composition according to the present embodiment further contains (C) an isocyanate compound having a trifunctional or higher function as a crosslinking agent. As a trifunctional or more than trifunctional isocyanate compound, For example, a biuret-modified body of diisocyanates, such as hexamethylene diisocyanate, isophorone diisocyanate, diphenylmethane diisocyanate, tolylene diisocyanate, and xylylene diisocyanate, and an isocyanurate-modified body. Sieves, trimethylolpropane, and adducts with trivalent or higher polyols, such as glycerol, etc. are mentioned. (C) As a ratio of the trifunctional or more than trifunctional isocyanate compound which is a crosslinking agent, it is preferable to contain in the ratio of 0.1-10 weight part with respect to 100 weight part of acrylic polymer, for example, Containing in the ratio of 0.1-6 weight part more preferably.

The pressure-sensitive adhesive composition according to the present embodiment may contain (E) a ketoenol tautomer compound. (E) Ketoenol tautomer compounds include methyl acetoacetate, ethyl acetoacetate, octyl acetoacetate, oleyl acetoacetate, lauryl acetoacetate, β-ketoester such as stearyl acetoacetate, acetylacetone, 2 and β-diketones such as ,4-hexanedione and benzoylacetone. In the adhesive composition which uses a polyisocyanate compound as a crosslinking agent, by blocking the isocyanate group which a crosslinking agent has, excessive viscosity rise and gelation of the adhesive composition after mixing|blending of a crosslinking agent are suppressed, and the pot life of an adhesive composition can be extended. (E) The ketoenol tautomer compound is preferably at least one selected from the group consisting of acetylacetone and ethyl acetoacetate. It is preferable to contain the (E) ketoenol tautomer compound in a ratio of 0.1 to 300 parts by weight with respect to 100 parts by weight of the acrylic polymer.

The adhesive composition which concerns on this embodiment may contain the crosslinking accelerator of (D) a metal chelate compound. (D) The crosslinking accelerator of the metal chelate compound may be any substance that functions as a catalyst for the reaction (crosslinking reaction) of the copolymer and the crosslinking agent when a polyisocyanate compound is used as a crosslinking agent. (D) The crosslinking accelerator of the metal chelate compound is a compound in which one or more polydentate ligands L are bonded to a 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. Specific examples of the metal chelate compound include tris(2,4-pentanedionate)iron(III), iron trisacetylacetonate, titanium trisacetylacetonate, ruthenium trisacetylacetonate, zinc bisacetylacetonate, aluminum tris Acetylacetonate, zirconium tetrakisacetylacetonate, tris(2,4-hexanedionate)iron(III), bis(2,4-hexanedionate)zinc, tris(2,4-hexanedionate)titanium, Tris(2,4-hexanedionate)aluminum, tetrakis(2,4-hexanedionate)zirconium, etc. are mentioned.

(D) The crosslinking accelerator of the metal chelate compound is preferably at least one metal chelate compound selected from the group consisting of an aluminum chelate compound, a titanium chelate compound, and an iron chelate compound. It is preferable to contain the crosslinking accelerator of (D) a metal chelate compound in the ratio of 0.001-0.5 weight part with respect to 100 weight part of said acrylic polymers.

(E) the ketoenol tautomer compound has an effect of inhibiting crosslinking as opposed to the crosslinking accelerator of (D) the metal chelate compound, It is preferable to appropriately set the ratio of the crosslinking accelerator. In order to lengthen the pot life of an adhesive composition and to improve storage stability, it is preferable that the weight part ratio of (E)/(D) is 70-1000, It is more preferable that it is 70-700, It is 70-300 Especially preferred. Here, the weight part ratio of (E)/(D) is the value of the quotient obtained by dividing the weight part of (E) by the weight part of (D).

The pressure-sensitive adhesive composition according to the present embodiment may contain (H) a polyether-modified siloxane compound as an optional component. (H) The polyether-modified siloxane compound is a siloxane compound having a polyether group, and in addition to the normal siloxane unit [-SiR ¹ ₂ -O-], a siloxane unit having a polyether group [-SiR ¹ (R ² O(R ³ O) ) _n R ⁴ )-O-]. Here, R ¹ is one or more alkyl or aryl groups, R ² and R ³ are one or two or more alkylene groups, R ⁴ is one or more alkyl or acyl groups (terminal groups) indicates. Examples of the polyether group include polyoxyalkylene groups such as polyoxyethylene group [(C ₂ H ₄ O) _n ] and polyoxypropylene group [(C ₃ H ₆ O) _n ]. In the siloxane unit having a polyether group, the terminal of the polyether group may be an OH group (R ⁴ =H in the above formula).

(H) The polyether-modified siloxane compound is preferably a polyether-modified siloxane compound having an HLB value of 6 to 12. In addition, with respect to 100 parts by weight of the acrylic polymer, (H) polyether-modified siloxane compound is preferably contained in an amount of 0.01 to 0.5 parts by weight, more preferably 0.02 to 0.35 parts by weight, and 0.02 to 0.25 parts by weight. It is particularly preferable to be An HLB value is a hydrophilic-lipophilic balance (hydrophilic-lipophilic ratio) prescribed|regulated, for example by JISK3211 (surfactant term) etc.

The polyether-modified siloxane compound can be obtained by, for example, grafting an organic compound having an unsaturated bond and a polyoxyalkylene group to a polyorganosiloxane main chain having a silicon hydride group by hydrosilylation reaction. Specifically, dimethylsiloxane/methyl (polyoxyethylene) siloxane copolymer, dimethylsiloxane/methyl (polyoxyethylene) siloxane/methyl (polyoxypropylene) siloxane copolymer, dimethylsiloxane/methyl (polyoxypropylene) siloxane polymer, etc. can be heard

(H) By mix|blending a polyether modified siloxane compound with an adhesive composition, the adhesive force of an adhesive layer and rework performance can be improved. (H) It is preferable that the weight average molecular weight of a polyether modified siloxane compound is 10000 or less. From the viewpoint of compatibility with the acrylic polymer, the lower the HLB value and the lower the molecular weight, the better the compatibility. However, in the case of a polyether-modified siloxane compound having a low molecular weight, the HLB value is relatively high and the compatibility with the polymer is slightly low, but excellent antistatic properties this is obtained

The pressure-sensitive adhesive composition of the present embodiment is not limited to the additives described above, and well-known additives such as surfactants, curing accelerators, plasticizers, fillers, curing retarders, processing aids, antioxidants, and antioxidants may be appropriately blended. These can be used individually or in combination of 2 or more types.

The adhesive composition of this embodiment is suitable as an adhesive composition for surface protection films bonded by the polarizer protective layer of a polarizing plate. Here, the polarizer protective layer of the polarizing plate may be one selected from the group consisting of a TAC-based film, a PMMA-based film, and a PET-based film. Here, TAC is an abbreviation of triacetyl cellulose, PMMA is polymethyl methacrylate, and PET is an abbreviation of polyethylene terephthalate.

Further, the surface treatment applied to the surface of the polarizer protective layer of the polarizing plate may be one selected from the group consisting of untreated, AG treatment, LR treatment, AR treatment, AG-LR treatment, and AG-AR treatment. Here, AG is anti-glare, LR is low reflection, and AR is anti-reflection.

The pressure-sensitive adhesive layer in which the pressure-sensitive adhesive composition of the present embodiment is crosslinked has a surface resistivity of preferably 1.0×10 ⁺¹² Ω/□ or less, more preferably 5.0×10 ⁺¹¹ Ω/□ or less, and 1.0×10 ⁺¹¹ Ω/□ or less. It is especially preferable that it is the following. When the surface resistivity is large, the performance for dissipating static electricity generated when the pressure-sensitive adhesive layer is peeled from the adherend is poor. For this reason, by making the surface resistivity sufficiently small, the peeling electrification voltage which arises accompanying static electricity which arises when peeling an adhesive layer from a to-be-adhered body is reduced, and it can suppress that it affects a to-be-adhered body.

The pressure-sensitive adhesive layer in which the pressure-sensitive adhesive composition of the present embodiment is crosslinked has a peeling electrification voltage of the pressure-sensitive adhesive layer of ±0.3 kV or less, i.e., -0.3 to It is preferable to exist in the range of +0.3 kV. Examples of the fluorine compound used in the composition for forming a low refractive index layer include a fluorinated copolymer which is one or two or more polymers such as fluorinated olefins, fluorinated vinyl ethers, and fluorinated alkyl (meth) acrylates, and fluorinated alkyl group-containing silane compounds. Condensates, such as these are mentioned. The fluorinated copolymer may be copolymerized with fluorinated monomers and non-fluorinated monomers such as olefins, vinyl ethers and (meth)acrylates. The low-refractive-index layer may be combined with a high-refractive-index layer or the like to constitute an antireflection layer.

When measuring the peel electrification voltage with respect to a low-refractive-index layer, as a base material for forming a low-refractive-index layer on the surface, a PMMA base material and a TAC base material are mentioned. In addition, the pressure-sensitive adhesive layer in which the pressure-sensitive adhesive composition of the present embodiment is crosslinked has a peel electrification voltage of ±0.3 kV or less, that is, −0.3 to +0.3 kV, with respect to the plane layer on which the surface of the PMMA substrate or the TAC substrate is not subjected to any treatment. It is preferable to be within the range of

After the pressure-sensitive adhesive layer is bonded to the adherend, it is left for 48 hours in an atmosphere of a temperature of 60° C. and a humidity of 90% RH, and the contamination resistance performance after one day after being taken out from the atmosphere is “no contamination” with respect to the surface of the adherend. desirable. Examples of the adherend include a polarizing plate in which a protective layer is laminated on a polarizer and the surface of the protective layer is treated with a composition containing a fluorine compound to have a low reflection surface. The composition containing the fluorine compound used for low-reflection surface treatment may be the same as or different from the resin composition for low-refractive-index layer formation containing the fluorine compound mentioned above. Examples of the protective layer include a PMMA substrate and a TAC substrate.

The adhesive force of the adhesive layer formed by crosslinking the pressure-sensitive adhesive composition of the present embodiment to the low refractive index layer applied to the surface of the PMMA substrate is 0.04 to 0.2 N/25 mm at a low-speed peeling rate of 0.3 m/min, and high-speed It is preferable that the adhesive force in 30 m/min of peeling rates is 2.0 N/25 mm or less, and it is more preferable that the adhesive force in 30 m/min of high-speed peeling rates is 0.2-1.6 N/25 mm. For this reason, the performance with little change in adhesive force also with peeling speed is acquired, and it becomes possible to peel quickly also by high-speed peeling. Moreover, even when peeling the surface protection film once for re-adhesiveness, it does not require excessive force and it is easy to peel from a to-be-adhered body.

It is preferable that it is 95-100 %, and, as for the gel fraction of the adhesive layer formed by bridge|crosslinking the adhesive composition of this embodiment, it is more preferable that it is 97-100 %. As described above, since the gel fraction of the pressure-sensitive adhesive layer is high, the adhesive force is not excessive at a low peel rate, the elution of unpolymerized monomers or oligomers from the copolymer is reduced, and the reworkability and durability at high temperature and high humidity are improved. contamination of the adherend can be suppressed.

The adhesive film of this embodiment forms the adhesive layer formed by bridge|crosslinking the adhesive composition of this embodiment on one side or both surfaces of a resin film. Moreover, the surface protection film of this embodiment is a surface protection film formed by forming in one surface of a resin film the adhesive layer formed by bridge|crosslinking the adhesive composition of this embodiment. The adhesive composition of this embodiment is equipped with the outstanding antistatic performance, it is excellent in the balance of adhesive force in a low-speed peeling rate and a high-speed peeling rate, and has stain-resistance performance. For this reason, it can use suitably as a use of the surface protection film of a polarizing plate.

A resin film, such as a polyester film, etc. can be used as the base film of an adhesive layer, and the release film (separator) which protects an adhesive surface.

Antistatic treatment and antifouling treatment may be given to the surface opposite to the side in which the said adhesive layer of one side of a resin film was formed. As antistatic treatment, application|coating, mixing, etc. of an antistatic agent are mentioned. As an antifouling|stain-resistant treatment, the process by a silicone type, a fluorine type mold release agent, a coating agent, silica microparticles|fine-particles, etc. is mentioned. The release film may be subjected to a release treatment with a silicone-based, fluorine-based, or long-chain alkyl-based mold release agent or the like on the surface on the side aligned with the pressure-sensitive adhesive surface of the pressure-sensitive adhesive layer.

Moreover, the optical film with an adhesive layer can be obtained by laminating|stacking the adhesive layer which bridge|crosslinked the adhesive composition of this embodiment on at least one surface of an optical film. As an optical film, a polarizing film, retardation film, an antireflection film, an anti-glare (anti-glare) film, an ultraviolet-ray absorption film, an infrared-absorbing film, an optical compensation film, a brightness improvement film, etc. are mentioned. As an apparatus to which an optical member is applied, a liquid crystal panel, organic electroluminescent panel, a touch panel, etc. are mentioned.

In the case of a surface protection film for optics, such as a surface protection film for polarizing plates, and an adhesive film, it is preferable that a base film and an adhesive layer have sufficient transparency.

Example

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

<Production of acrylic polymer>

[Example 1]

Nitrogen gas was introduced into a reaction apparatus equipped with a stirrer, a thermometer, a reflux condenser, and a nitrogen introduction tube, and the air in the reaction apparatus was replaced with nitrogen gas. Then, the solvent (ethyl acetate) was added to the reaction apparatus with 100 weight part of 2-ethylhexyl acrylates, 6.0 weight part of 8-hydroxyoctyl acrylate, and 0.1 weight part of acrylic acid. Then, 0.1 weight part of azobisisobutyronitrile as a polymerization initiator was dripped over 2 hours, it was made to react at 65 degreeC for 6 hours, and the acrylic polymer used for Example 1 was obtained.

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

Examples 2 to 6 were carried out in the same manner as in the acrylic polymer solution used in Example 1, except that the monomer composition was the same as described in Table 1 (A), (B-1) and (B-2), respectively. And acrylic polymer solutions used in Comparative Examples 1 to 3 were obtained.

<Preparation of adhesive composition and surface protection film>

[Example 1]

With respect to the acrylic polymer solution of Example 1 prepared as above, 2.5 parts by weight of a crosslinking agent (Coronate HX), 1.5 parts by weight of an antistatic agent (1-octyl-2-methylpyridinium trifluoromethanesulfonate salt), crosslinking 0.1 parts by weight of a catalyst (titanium trisacetylacetonate) and 8.5 parts by weight of acetylacetone were added, stirred and mixed, and the pressure-sensitive adhesive composition of Example 1 was obtained. After apply|coating this adhesive composition on the release film (silicone resin-coated PET film), the solvent was removed by drying at 90 degreeC, and the 20-micrometer-thick adhesive layer was obtained. Thereafter, the adhesive layer with the release film formed on the opposite side to the antistatic and antifouling side of the base film (PET film with antistatic and antifouling treatment on one side) is transferred, and “base film / adhesive layer / The surface protection film of Example 1 which has the laminated constitution of "release film" was obtained.

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

The surface protection films of Examples 2 to 6 and Comparative Examples 1 to 3 were prepared in the same manner as in the surface protection film of Example 1, except that the composition of the additive was as described in (C) to (F) of Table 1, respectively. got it

In Table 1, the weight part of each component was calculated|required as 100 weight part of the sum total of the C1-C18 (meth)acrylic acid ester monomer of (A) alkyl group.

Here, in Table 1, in each column of (C)-(F), 100 weight part of acrylic polymer was made into, and the content ratio (weight part) of each component was shown with the numerical value in parentheses (　).

In addition, the compound names of the abbreviations of each component used in Table 1 are shown in Table 2. Here, Coronate (registered trademark) HX, HL and L are trade names of Tosoh Corporation, and Takenate (registered trademark) D-140N, D-127N, and D-110N are trade names of Mitsui Chemicals Corporation.

(F) Among the antistatic agents, F-1 to F-6 and F-9 are ionic compounds having a melting point of 25°C or more and 80°C or less, and are solid at room temperature. F-7 and F-8 are ionic compounds that have a melting point greater than 80° C. and are solid at room temperature.

<Test method and evaluation>

After aging the surface protection films in Examples 1-6 and Comparative Examples 1-3 in the atmosphere of a temperature of 23 degreeC, and a humidity of 50 %RH, respectively for 7 days, the following test method evaluated.

<Test method of adhesion>

After peeling the release film and exposing the pressure-sensitive adhesive layer, the surface protection film was bonded to the surface of the polarizing plate through the pressure-sensitive adhesive layer, left for 1 day, and then autoclaved at 50° C., 5 atmospheres, 20 minutes, and further 12 at room temperature. What was left to stand for time was made into the measurement sample of adhesive force. The obtained measurement sample was peeled at a low speed (0.3 m/min) or high speed (30 m/min) using a tensile tester in a 180 degree direction, and the measured peeling strength was made into adhesive force.

Here, the polarizer protective layer of the polarizing plate is one selected from the group consisting of triacetyl cellulose (TAC), polymethyl methacrylate (PMMA), and polyethylene terephthalate (PET).

In the LR polarizing plate and the AG-LR polarizing plate, the surface of the polarizer protective layer of the polarizing plate is subjected to a low-reflection surface treatment with a composition containing a fluorine compound.

<Test method of surface resistivity>

After aging the surface protection film, before bonding to the polarizing plate, the release film is peeled to expose the pressure-sensitive adhesive layer, and the surface resistivity of the pressure-sensitive adhesive layer is measured using a resistivity meter Hirestar UP-HT450 (manufactured by Mitsubishi Chemical Analytech). did.

<Test method of peeling electrification voltage>

The surface protection film in which the release film was peeled and the adhesive layer was exposed was bonded to the polarizing plate which has the low-refractive-index layer formed using the composition for low-refractive-index layer formation containing a fluorine compound on the to-be-adhered surface. When the surface protection film is peeled 180° at a tensile speed of 30 m/min, the voltage (charged voltage) generated by the charging of the adherend is measured using high-precision electrostatic sensors SK-035, SK-200 (manufactured by Keyence Co., Ltd.) , the maximum value of the measured values was taken as the peel electrification voltage.

<Test method of stain resistance performance>

The polarizing plate which gave the low reflection (LR) surface treatment on one surface of the glass plate was bonded together through the adhesive layer (double-sided adhesive tape) using the bonding machine. Then, the surface protection film was bonded together on the surface of the said polarizing plate using the bonding machine. After bonding to an adherend, it was left to stand for 48 hours in the atmosphere of the temperature of 60 degreeC, and 90%RH of humidity, it took out from the said atmosphere, the surface protection film was peeled after 1 day, and the contamination state on the surface of a polarizing plate was observed visually. As for the judgment criteria of stain resistance performance, the case where there was no stain|pollution|contamination on the surface of the said polarizing plate was evaluated as "○", the case where there was a little stain|pollution|contamination by "Δ", and the case where there was stain|pollution|contamination was evaluated as "x".

In Table 3, the evaluation result about the surface protection film in Examples 1-6 and Comparative Examples 1-3 is shown. "Surface resistivity" was expressed by the method (however, m is an arbitrary real value, and n is a positive integer) in which "mx10+ ⁿ " is "mE+n".

The column of "Peel electrification voltage" shows the material (TAC or PMMA) and surface treatment (Plain or AG-LR) of the polarizer protective layer of the polarizing plate used in the test. Plain of "surface treatment" means untreated. It carried out similarly also to the column of "pollution resistance performance", and the material (PMMA) and surface treatment (AG-LR) of the polarizer protective layer of the polarizing plate used by the test were shown.

The surface protection films of Examples 1 to 6 had an adhesive force of 0.04 to 0.2 N/25 mm at a low peel rate of 0.3 m/min to a polarizing plate as an adherend, and an adhesive force of 2.0 N/25 mm at a high peel rate of 30 m/min. It was the following and was excellent in adhesive performance.

In addition, the surface protection films of Examples 1 to 6 have a surface resistivity of the pressure-sensitive adhesive layer of 1.0×10 ⁺¹² Ω/□ or less, and a low-refractive-index layer formed using a composition for forming a low-refractive-index layer containing a fluorine compound. The peeling electrification voltage of the layer was in the range of -0.3 to +0.3 kV, and the antistatic performance was excellent.

Further, the surface protection films of Examples 1 to 6 had a peeling electrification voltage of the pressure-sensitive adhesive layer in the range of -0.3 to +0.3 kV, even for untreated PMMA substrates and TAC substrates not having a low refractive index layer, and antistatic performance This was excellent.

Further, the surface protection films of Examples 1 to 6 were adhered to an adherend, left to stand for 48 hours in an atmosphere of a temperature of 60° C. and a humidity of 90% RH, and taken out from the atmosphere, and a polarizing plate subjected to a low-reflection surface treatment as an adherend even after 1 day. There was no contamination, and the contamination resistance performance was excellent.

That is, the evaluation results shown in Table 3 for the surface protection films of Examples 1 to 6 demonstrate that the subject of the present invention can be solved.

The surface protection film of Comparative Example 1 contains an antistatic agent having a melting point of more than 80°C. For this reason, the surface protection film of the comparative example 1 had the large adhesive force of an adhesive layer, the peeling electrification voltage was high, and the stain resistance performance was also inferior.

Moreover, the surface protection film of Comparative Example 2 contains the antistatic agent whose melting|fusing point is more than 80 degreeC. For this reason, the surface protection film of the comparative example 2 had the large adhesive force of an adhesive layer, the peeling electrification voltage was high, and the stain resistance performance was also inferior.

Moreover, although melting|fusing point of the surface protection film of the comparative example 3 is 25-80 degreeC, the anion contains the antistatic agent which has an imide group. For this reason, the surface protection film of the comparative example 3 had a high peeling electrification voltage with respect to a PMMA base material, and its stain resistance performance was also inferior.

Thus, in the surface protection film of Comparative Examples 1-3, the subject of this invention could not be solved.

Claims (7)

A pressure-sensitive adhesive composition comprising an acrylic polymer, (F) an antistatic agent, (C) a crosslinking agent, and (D) a crosslinking accelerator for a metal chelate compound,
(F) the antistatic agent is an ionic compound that is a solid at a temperature of 23 ° C with a melting point of 25 to 80 ° C represented by the following formula (1),
K ⁺ A ^- (1)
[In formula (1), K ⁺ is pyridinium, imidazolium, phosphonium, sulfonium, pyrrolidinium, guanidinium, ammonium, isouronium, thiouronium, piperidinium, pyrazolium, methylium , is one kind of cation selected from the group consisting of morpholinium, and A ^- is one kind of anion selected from the group consisting of trifluoromethanesulfonate anion and pentafluoroethanesulfonate anion not containing an imide group ]
The acrylic polymer is
(A) With respect to a total of 100 parts by weight of at least one or more types of (meth)acrylic acid ester monomers having C1 to C18 alkyl group, (B-1) 0.01 to at least one type of copolymerizable vinyl monomer containing a hydroxyl group 10 parts by weight, and/or (B-2) an acrylic polymer of a copolymer copolymerized in a ratio of 0.01 to 0.5 parts by weight of the total of at least one type of copolymerizable vinyl monomer containing a carboxyl group,
Isooctyl (meth)acrylate, isononyl (meth)acrylate, 2-ethylhexyl (meth) in a total of 100 parts by weight of at least one or more types of (meth)acrylic acid ester monomers having C1 to C18 alkyl group (A) ) is made by containing at least one selected from the group consisting of acrylates in a proportion of 50 parts by weight or more,
Based on 100 parts by weight of the acrylic polymer, the ionic compound is contained as an essential component in a ratio of 0.01 to 10 parts by weight,
(D) the crosslinking accelerator of the metal chelate compound is tris(2,4-pentanedionate)iron(III), titanium trisacetylacetonate, aluminum trisacetylacetonate, tris(2,4-hexanedionate)titanium, and tris (2,4-hexanedionate) at least one selected from the group consisting of aluminum,
The adhesive force of the adhesive layer formed by crosslinking the adhesive composition to the low refractive index layer applied to the surface of the polymethyl methacrylate substrate is 0.04 to 0.2 N/25 mm, and the adhesive force at a low peeling rate of 0.3 m/min is, Further, the adhesive composition at a high-speed peeling rate of 30 m/min is 2.0 N/25 mm or less. The method of claim 1,
With respect to 100 parts by weight of the acrylic polymer, the (C) cross-linking agent is made by containing a trifunctional or more isocyanate compound in a ratio of 0.1 to 10 parts by weight,
The pressure-sensitive adhesive composition further comprises (E) a ketoenol tautomer compound. 3. The method of claim 1 or 2,
(B-1) The copolymerizable vinyl monomer containing a hydroxyl group is 8-hydroxyoctyl (meth) acrylate, 6-hydroxyhexyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, 2- At least one selected from the group consisting of hydroxyethyl (meth) acrylate, N-hydroxy (meth) acrylamide, N-hydroxymethyl (meth) acrylamide, and N-hydroxyethyl (meth) acrylamide ego,
(B-2) the copolymerizable vinyl monomer containing a carboxyl group is (meth)acrylic acid, carboxyethyl (meth)acrylate, carboxypentyl (meth)acrylate, 2- (meth)acryloyloxyethylhexahydrophthalic acid, 2-(meth)acryloyloxypropylhexahydrophthalic acid, 2-(meth)acryloyloxyethylphthalic acid, 2-(meth)acryloyloxyethyl succinic acid, 2-(meth)acryloyloxyethyl maleic acid , carboxypolycaprolactone mono(meth)acrylate, and 2-(meth)acryloyloxyethyltetrahydrophthalic acid. A pressure-sensitive adhesive composition, characterized in that at least one selected from the group consisting of compounds. 3. The method of claim 2,
In the pressure-sensitive adhesive composition, based on 100 parts by weight of the acrylic polymer, 0.001 to 0.5 parts by weight of the (D) metal chelate compound crosslinking accelerator and (E) 0.1 to 300 parts by weight of the ketoenol tautomer compound It is made by containing
The pressure-sensitive adhesive composition, characterized in that the ratio by weight of (E) / (D) is 70 to 1000. An adhesive film in which a pressure-sensitive adhesive layer obtained by crosslinking the pressure-sensitive adhesive composition according to claim 1 or 2 is laminated on one surface of a resin film. A surface protection film using the adhesive film of claim 5 . An optical film in which a pressure-sensitive adhesive layer is formed on at least one surface of the optical film, wherein the pressure-sensitive adhesive layer obtained by crosslinking the pressure-sensitive adhesive composition of claim 1 or 2 is laminated.