TWI812708B - Adhesive composition - Google Patents

Abstract

The present invention provides an adhesive composition, and an adhesive film and an surface protecting film using the same. The adhesive composition has an excellent adhesion property, which is balanced at a low-speed peeling speed and a high-speed peeling speed, and achieves both an antistatic property and an anti-contamination property at the same time. In the adhesive composition, an (F) antistatic agent is an ionic compound having a melting point of 25 to 80 ℃ represented by the formula (1) K⁺ ‧A^- , and in the formula (1), K⁺ is a cation, and A^- is an anion selected from the group consisting of a trifluoromethanesulfonate anion and a pentafluoroethanesulfonate anion and having no imide group, and an acrylic polymer is an acrylic polymer having a glass transition temperature of 0 ℃ 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.

Description

Adhesive composition

The present invention relates to an adhesive composition containing an antistatic agent, as well as an adhesive film and a surface protective film using the adhesive composition. More specifically, the present invention relates to providing an adhesive composition that can achieve low peeling speed and high peeling speed, and an adhesive film and surface protective film using the same. Excellent adhesive properties such as balanced adhesive force, while achieving both antistatic and anti-pollution properties.

Conventionally, in the manufacturing process of optical members such as polarizing plates that are components of a liquid crystal display, a surface protective film has been bonded to temporarily protect the surface of the optical member. This surface protective film is used only in the step of manufacturing the optical member, and when the optical member is mounted on a liquid crystal display, it is peeled off and removed from the optical member. Since such a surface protection film for protecting the surface of an optical member is used only during the manufacturing step of the optical member, it is often also called a step film.

In this type of surface protective film used in the step of manufacturing an optical member, an adhesive layer is formed on one side of an optically transparent polyethylene terephthalate (PET) resin film. Before being bonded to the optical component, in order to protect the adhesive layer of the surface protective film, a release film that has undergone release treatment is bonded to the surface of the adhesive layer. In addition, optical components such as polarizing plates are subjected to product inspections involving optical evaluation of display capabilities, color tone, contrast, inclusion of impurities, etc. of liquid crystal display panels in a state where surface protective films are bonded to them. Therefore, as performance requirements for the surface protective film, it is required that the adhesive layer does not adhere to bubbles or impurities and low molecular weight components of the adhesive composition, that is, it is required to have anti-pollution properties. In addition, when the surface protective film is peeled off from optical components such as polarizers, the peeling static electricity generated when peeling off the adhesive layer and the adherend may cause malfunction of the electrical control circuit of the liquid crystal display. Therefore, the adhesive layer of the surface protective film is required to have excellent antistatic properties. Furthermore, in recent years, in addition to the conventionally used triacetylcellulose (TAC), polymethyl methacrylate (PMMA) has been widely used as a protective layer (sometimes called a protective film) of polarizers of polarizers. Utilize materials that easily generate static electricity when peeling off the surface of the polarizing plate, such as acrylic resin, polyester resin such as polyethylene terephthalate (PET), cyclic olefin polymer, and polycarbonate. Therefore, the antistatic performance required for the adhesive layer used in the surface protective film of the polarizing plate needs to be better than ever before. In addition, when the surface protective film is finally peeled off from an optical member such as a polarizing plate, it is required to be able to peel it off quickly. That is, it is required that the change in adhesive force due to peeling speed is small so that rapid peeling can be achieved even in the case of high-speed peeling.

As mentioned above, in recent years, from the perspective of ease of use when using a surface protective film, the adhesive layer constituting the surface protective film is required to have the following properties: (1) Obtain adhesion at a low peeling speed and a high peeling speed Balance of forces; (2) Anti-pollution properties; (3) Excellent anti-static properties. However, regarding the required performance of the adhesive layer constituting the surface protective film, even if the individual required performances of (1) to (3) above can be satisfied respectively, the requirements for the adhesive layer of the surface protective film (1) to (1) to (3) can be satisfied at the same time. The full required performance of (3) is also a very difficult technical issue.

In order to solve such technical problems, for example, (1) achieving a balance of adhesive force at low and high peeling speeds, (2) having anti-pollution properties, and (3) having excellent antistatic properties, respectively, have been I know the following plan.

Regarding (1) achieving a balance of adhesive force between a low peeling speed and a high peeling speed, a combination of an alkyl (meth)acrylate having an alkyl group with 7 or less carbon atoms and a carboxyl group-containing copolymerizable compound In an acrylic adhesive layer composed of a copolymer as the main component and cross-linked with a cross-linking agent, after a long period of adhesion, the adhesive may move to the side of the adherend and adhere to the adherend. Sticky objects, or the problem of a large increase in adhesion to the adhered object over time. In order to avoid this problem, a technical solution is known in which an adhesive layer is provided with an alkyl (meth)acrylate having an alkyl group with 8 to 10 carbon atoms and an alcoholic hydroxyl group. An adhesive layer formed by cross-linking a copolymer of a copolymerizable compound with a cross-linking agent (Patent Document 1). In addition, a technical solution has also been proposed in which the following adhesive layer is provided. The adhesive layer is the same copolymer as above, mixed with a small amount of alkyl (meth)acrylate and a copolymer containing carboxyl groups. The adhesive layer is a copolymer of a chemical compound and cross-linked with a cross-linking agent. However, if they are used for surface protection of plastic sheets with low surface tension and smooth surfaces, there is also a problem of peeling phenomena such as floating due to heating during processing or storage, and high-speed peeling in the field of manual operation. The problem of poor re-peelability.

In order to solve these problems, an adhesive composition is proposed, which contains a) (meth)acrylic acid alkyl ester having an alkyl group with 8 to 10 carbon atoms as a main component. To 100 parts by weight, add 1 to 15 parts by weight of b) a carboxyl group-containing copolymerizable compound and 3 to 100 parts by weight of c) the vinyl ester of an aliphatic carboxylic acid with 1 to 5 carbon atoms to form a monomer. A copolymer of the mixture is blended into the copolymer, and a crosslinking agent is blended into the copolymer in an amount equal to or more than the carboxyl group of component b) (Patent Document 2). The adhesive composition described in Patent Document 2 does not cause peeling phenomena such as floating during processing or storage, has a small increase in adhesive force over time, and has excellent removability even when stored for a long time, especially at high temperatures. Even if it is stored in the air for a long time, it can be peeled off again with a small force. At this time, no adhesive residue will be produced on the adherend, and even when peeling off at a high speed, it can be peeled off again with a small force. However, in the adhesive composition described in Patent Document 2, since the gel fraction of the adhesive layer in Examples 1 to 3 is 90%, unpolymerized monomers or oligomers are easily eluted from the copolymer. In addition, Patent Document 2 does not describe antistatic properties and anti-pollution properties. When a material that easily generates peeling static electricity is used as an adherend, it may be difficult to produce an adhesive with excellent antistatic properties and anti-pollution properties. Agent layer problem.

In addition, regarding (2) having anti-pollution properties, an adhesive composition is disclosed, which contains: 100 parts by mass of a carboxyl group-containing monomer from 0 to less than 0.5 parts by mass, and 0.6 to 9 parts by mass of a hydroxyl group-containing monomer. A (meth)acrylic copolymer composed of (meth)acrylic monomers and 99.4 to 90.5 parts by mass of (meth)acrylate monomers, with a weight average molecular weight of more than 100,000 and less than 1 million; and 0.1 ~5 parts by mass of carbodiimide cross-linking agent (Patent Document 3). The adhesive composition described in Patent Document 3 is characterized by using a carbodiimide cross-linking agent as a cross-linking agent for a (meth)acrylic copolymer of a specific composition. This makes it possible to form a cross-linked structure in the adhesive layer that can follow shrinkage caused by pressure and temperature during autoclaving. Therefore, the adhesive layer formed using the adhesive composition described in Patent Document 3 can suppress and prevent bubbling even under high-temperature and high-pressure conditions (during autoclave treatment), has excellent anti-fouling properties, and has excellent transparency. . However, although the adhesive composition described in Patent Document 3 has improved anti-pollution performance, it cannot achieve both excellent adhesive performance and antistatic performance, and there are still technical problems that need to be further solved.

In addition, regarding (3) having excellent antistatic properties, as a method for imparting antistatic properties to a surface protective film, a method of kneading an antistatic agent into a base film and the like are known. As antistatic agents, for example, (a) various cationic antistatic agents having cationic groups such as quaternary ammonium salts, pyridinium, and primary to tertiary amine amine groups are disclosed; (b) various cationic antistatic agents having sulfonate groups, sulfate esters, etc. Anionic antistatic agents with anionic groups such as salt base, phosphate ester base, and phosphonate base; (c) Amphoteric antistatic agents such as amino acids and amino sulfate esters; (d) Amino alcohols and glycerols , nonionic antistatic agents such as polyethylene glycols; (e) polymeric antistatic agents obtained by polymerizing the above antistatic agents (Patent Document 4). However, regarding the surface protective film described in Patent Document 4, although there is a description of imparting antistatic properties related to the adhesion of garbage to the adherend, there is no description of a method for achieving both excellent adhesion performance and anti-pollution performance, and there is still a need. Technical issues to be further resolved.

In addition, in recent years, a method has been proposed in which the adhesive layer directly contains an antistatic agent instead of containing the antistatic agent in the base film or coating the antistatic agent on the surface of the base film. For example, an antistatic adhesive composition is disclosed, which is characterized in that a salt having an anion containing a fluorine group and a sulfonyl group is dispersed in a state of being dissolved in a polyether ester plasticizer containing a polyether group in the main chain ( Patent document 5). Regarding the adhesive composition described in Patent Document 5, it is disclosed to use a plasticizer composed of the following ester: a monocarboxylic acid or a dicarboxylic acid having a saturated or unsaturated acyclic hydrocarbon group and a carbon An ester formed from an alcohol with a non-cyclic hydrocarbon group having 1 to 20 atoms; or an ester formed by epoxidation of an unsaturated group in the unsaturated non-cyclic hydrocarbon group. It is considered that by making the monocarboxylic acid or dicarboxylic acid having a saturated or unsaturated acyclic hydrocarbon group have a number of carbon atoms close to that of the acrylic monomer constituting the acrylic copolymer used for the adhesive layer. Number, the compatibility in the antistatic adhesive composition becomes good, and the plasticizer in the acrylic antistatic adhesive composition is properly maintained, so bleeding is suppressed. However, regarding the antistatic adhesive composition described in Patent Document 5, although improvements in antistatic performance and bleed-out are disclosed, there is no description of the ability to achieve a balance of adhesive force between a low peeling speed and a high peeling speed. There is still a technical problem of obtaining an adhesive composition with excellent adhesive properties. [Prior art documents] [Patent Document]

Patent Document 1: Japanese Patent Application Publication No. Sho 63-225677 Patent Document 2: Japanese Patent Application Publication No. 11-256111 Patent document 3: Japanese Patent Application Publication No. 2011-122054 Patent Document 4: Japanese Patent Application Publication No. 11-070629 Patent Document 5: Japanese Patent Application Publication No. 2014-118469

[Technical problem to be solved by this invention]

As mentioned above, there is no existing technology that can simultaneously solve the following required performance for the adhesive layer constituting the surface protective film: (1) achieving a balance of adhesive force at low peeling speed and high peeling speed; (2) having anti-pollution properties Performance; (3) Excellent antistatic properties. In addition, there has been a trade-off between the antistatic performance and the anti-contamination performance of the adherend in the adhesive layer formed using an adhesive composition with antistatic properties and the surface protective film using the adhesive layer. (trade-off) relationship, it is difficult to improve anti-pollution performance while maintaining antistatic performance. Furthermore, in recent years, as the types of adherend materials to which surface protection films are bonded have increased, and the surface treatments of adherends have also varied, it has become increasingly important to simultaneously display anti-pollution and antistatic properties for all adherends. difficulty.

The present invention was made in view of the above circumstances, and its technical problem is to provide an adhesive composition that can achieve a low peeling speed and an adhesive film and a surface protective film using the same. It has excellent adhesive properties such as balanced adhesive force at a high peeling speed, and can also achieve both antistatic properties and anti-pollution properties. [Technical means to solve technical problems]

The inventor of the present application discovered that an adhesive composition containing the following ionic compound as an antistatic agent can exhibit both antistatic properties and anti-pollution properties to the adherend, thereby completing the present invention. The ionic compound has a melting point of 25~ 80℃ and has trifluoromethanesulfonate anion or pentafluoroethanesulfonate anion, and is solid at room temperature. The adhesive composition containing the following ionic compound as an antistatic agent and the adhesive film and surface protective film using the adhesive composition of the present invention can achieve excellent adhesive performance, and can simultaneously achieve antistatic performance and anti-pollution performance. Taking both factors into consideration, the technical problems of the existing technology are solved. The ionic compound has a melting point of 25 to 80°C and has a trifluoromethanesulfonate anion or a pentafluoroethanesulfonate anion, and is solid at room temperature.

In order to solve the above technical problems, the present invention provides an adhesive composition, which is an adhesive composition containing an acrylic polymer, (F) an antistatic agent and (C) a cross-linking agent, wherein the (F) ) Antistatic agent is an ionic compound with a melting point of 25~80°C represented by the following general formula (1), K ⁺ ‧A ^- (1) In the general formula (1), K ⁺ is a cation, and A ^- is a free ion. An anion in the group consisting of the trifluoromethanesulfonate anion and the pentafluoroethanesulfonate anion without a acyl imine group. The acrylic polymer is an acrylic polymer with a glass transition temperature of 0° C. or lower, and contains the ionic compound as an essential component in a ratio of 0.01 to 10 parts by weight relative to 100 parts by weight of the acrylic polymer.

Preferably: the acrylic polymer is a total of 100 parts by weight of at least one or more (meth)acrylate monomers with a carbon number of C1 to 18 in the alkyl group of (A), based on (B-1) The total amount of at least one or more copolymerizable vinyl monomers containing hydroxyl groups is 0.01 to 10 parts by weight, and/or the total amount of at least one or more copolymerizable vinyl monomers containing carboxyl groups (B-2) An acrylic polymer of a copolymer obtained by copolymerization in a proportion of 0.01 to 0.5 parts by weight, at least one of (meth)acrylate monomers having a carbon number of C1 to 18 in the (A) alkyl group The above total of 100 parts by weight contains a group selected from the group consisting of isooctyl (meth)acrylate, isononyl (meth)acrylate, and 2-ethylhexyl (meth)acrylate in a proportion of 50 parts by weight or more At least one of the groups contains an isocyanate compound with a functionality of 3 or more as the (C) cross-linking agent in a ratio of 0.1 to 10 parts by weight relative to 100 parts by weight of the acrylic polymer, and the adhesive combination The material further contains (D) a cross-linking accelerator of a metal chelate compound and (E) a keto-enol tautomer compound.

Preferably, the surface resistivity of the adhesive layer formed by cross-linking the adhesive composition is 1.0×10 ⁺¹² Ω/□ or less, and the adhesive layer is formed using a low refractive index layer containing fluoride. The peeling electrostatic voltage of the low refractive index layer formed by the resin composition on the surface of the PMMA base material and TAC base material, and the peeling electrostatic voltage of the plane layer without any treatment on the surface of the PMMA base material and TAC base material are both ± 0.3kV or less, after the adhesive layer is attached to the adherend, it is placed in an atmosphere with a temperature of 60°C and a humidity of 90% RH for 48 hours. The anti-pollution performance after being taken out of the atmosphere for 1 day, for the above The surface of the adherend is "pollution-free". The adherend is a polarizer in which a protective layer is laminated on a polarizer and the surface of the protective layer is treated with a low-reflective surface using a composition containing fluoride. The adhesive force of the adhesive layer to the low refractive index layer applied to the surface of the PMMA substrate is 0.04~0.2N/25mm at a low peeling speed of 0.3m/min, and is 0.04~0.2N/25mm at a high speed peeling speed. The adhesion force at a speed of 30m/min is 2.0N/25mm or less.

Preferably: the (B-1) hydroxyl-containing copolymerizable vinyl monomer is selected from the group consisting of 8-hydroxyoctyl (meth)acrylate, 6-hydroxyhexyl (meth)acrylate, and 4-hydroxyhexyl (meth)acrylate. Hydroxybutyl ester, 2-hydroxyethyl (meth)acrylate, N-hydroxy(meth)acrylamide, N-hydroxymethyl(meth)acrylamide, N-hydroxyethyl(meth)acrylamide At least one or more of the compound group consisting of amines; The (B-2) carboxyl group-containing copolymerizable vinyl monomer is selected from (meth)acrylic acid, carboxyethyl (meth)acrylate, carboxypentyl (meth)acrylate, 2-(methyl)acrylate )Acryloxyethylhexahydrophthalic acid, 2-(meth)acryloxypropylhexahydrophthalic acid, 2-(meth)acryloxyethylphthalic acid, 2-(Meth)acryloxyethylsuccinic acid, 2-(meth)acryloxyethylmaleic acid, carboxypolycaprolactone mono(meth)acrylate, 2-(methyl) At least one of the compound group consisting of acryloxyethyl tetrahydrophthalic acid.

Preferably: the adhesive composition contains the cross-linking accelerator of the (D) metal chelate compound in a proportion of 0.001 to 0.5 parts by weight relative to 100 parts by weight of the acrylic polymer, and in an amount of 0.1 to 300 parts by weight. The ratio of parts by weight contains the (E) keto-enol tautomer compound, and the cross-linking accelerator of the (D) metal chelate compound is selected from the group consisting of aluminum chelate compounds, titanium chelate compounds, and iron chelate compounds. At least one or more compounds in the group, the weight part ratio of (E)/(D) is 70 to 1000.

Furthermore, the present invention provides an adhesive film characterized in that an adhesive layer obtained by cross-linking the adhesive composition is laminated on one side of the resin film.

Furthermore, the present invention provides a surface protective film using the above-mentioned adhesive film.

Furthermore, the present invention provides a surface protective film for polarizing plates using the above-mentioned adhesive film.

Furthermore, the present invention provides an optical film with an adhesive layer, wherein an adhesive layer obtained by crosslinking the adhesive composition is laminated on at least one surface of the optical film.

Furthermore, the present invention provides an adhesive film in which an antistatic treatment and an antifouling treatment are performed on one side of the resin film opposite to the side on which the adhesive layer is formed. [Effects of the invention]

Compared with existing adhesive compositions for surface protection films, the adhesive composition of the present invention has excellent adhesive properties and excellent anti-peeling electrostatic properties that do not deteriorate over time. In particular, compared with conventional surface protective films, the adherend is an antifouling layer containing fluoride laminated on the surface of the optical film, or a low refractive index layer forming composition containing fluoride is used. In the case of forming a low refractive index layer, the surface protective film of the present invention has excellent adhesion properties and excellent anti-peeling anti-static properties without deterioration over time, and has a significant effect of balancing anti-static properties and anti-pollution properties. That is, the adhesive composition of the present invention and the surface protective film using the adhesive composition have excellent adhesive properties and excellent anti-peeling properties that do not deteriorate over time, and therefore have great industrial utilization value.

Hereinafter, the present invention will be described based on preferred embodiments. The adhesive composition of this embodiment is an adhesive composition containing an acrylic polymer, (F) an antistatic agent, and (C) a cross-linking agent, and is characterized in that the (F) antistatic agent is the following general The ionic compound represented by the formula (1) has a melting point of 25~80°C, K ⁺ ‧A ^- (1) In the general formula (1), K ⁺ is a cation, and A ^- is selected from the group consisting of An anion in the group consisting of trifluoromethanesulfonate anion and pentafluoroethanesulfonate anion; The acrylic polymer is an acrylic polymer with a glass transition temperature below 0°C, relative to 100 parts by weight of all The acrylic polymer contains the ionic compound as an essential component in a proportion of 0.01 to 10 parts by weight.

The acrylic polymer used in the adhesive composition of this embodiment is a main component polymer of the adhesive composition, and is an acrylic polymer with a glass transition temperature of 0° C. or lower. Furthermore, it is preferable that the acrylic polymer is a copolymer containing (A) a (meth)acrylic acid ester monomer having a carbon number of C1 to 18 in the alkyl group as a main component.

(A) The (meth)acrylate monomer in which the alkyl group has C1 to 18 carbon atoms includes methyl (meth)acrylate, ethyl (meth)acrylate, and propyl (meth)acrylate. , butyl (meth)acrylate, isobutyl (meth)acrylate, amyl (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, (meth) Undecyl acrylate, dodecyl (meth)acrylate, tridecyl (meth)acrylate, myristyl (meth)acrylate, pentadecyl (meth)acrylate , cetyl (meth)acrylate, heptadecyl (meth)acrylate, stearyl (meth)acrylate, cyclopentyl (meth)acrylate, cyclopentyl (meth)acrylate Hexyl ester etc. The alkyl group of the (meth)acrylic acid alkyl ester monomer may be linear, branched, or cyclic.

In a total of 100 parts by weight of at least one (meth)acrylate monomer with a carbon number of C1 to 18 in the (A) alkyl group, the acrylic polymer used in the adhesive composition of this embodiment It is preferable to contain a compound selected from the group consisting of isooctyl (meth)acrylate, isononyl (meth)acrylate, (meth)acrylate in a proportion of 50 parts by weight or more, more preferably 60 parts by weight or more, particularly preferably 75 parts by weight or more. At least one member from the group consisting of 2-ethylhexyl methacrylate.

The acrylic polymer preferably used in the adhesive composition of this embodiment is a copolymer of (B-1) at least one or more copolymerizable vinyl monomers containing a hydroxyl group, and/or (B-2) a carboxyl group. An acrylic polymer is a copolymer of at least one type of vinyl monomer. The acrylic polymer may be copolymerized with at least one of (B-1) a hydroxyl group-containing copolymerizable vinyl monomer and (B-2) a carboxyl group-containing copolymerizable vinyl monomer, or both of these may be copolymerized. kind of monomer. Preferably, the acrylic polymer is: 100 parts by weight in total of at least one (meth)acrylate monomer with a carbon number of C1 to 18 in the alkyl group of (A), based on (B-1) The total amount of at least one or more copolymerizable vinyl monomers containing hydroxyl groups is 0.01 to 10 parts by weight, and/or the total amount of at least one or more copolymerizable vinyl monomers containing carboxyl groups (B-2) The acrylic polymer is a copolymer formed by copolymerization in a proportion of 0.01 to 0.5 parts by weight.

The acrylic polymer used in the adhesive composition of this embodiment may be copolymerized with (B-1) a copolymerizable monomer containing a hydroxyl group. (B-1) The copolymerizable monomer containing a hydroxyl group is preferably selected from the group consisting of 8-hydroxyoctyl (meth)acrylate, 6-hydroxyhexyl (meth)acrylate, and 4-hydroxybutyl (meth)acrylate. , 2-hydroxyethyl (meth)acrylate, N-hydroxy(meth)acrylamide, N-hydroxymethyl(meth)acrylamide, N-hydroxyethyl(meth)acrylamide, etc. At least one or more of the compound groups. When copolymerizing (B-1) a hydroxyl-containing copolymerizable monomer, a total of 100 parts by weight of at least one (meth)acrylate monomer with a carbon number of C1 to 18 in the alkyl group of (A) , preferably contains (B-1) a hydroxyl-containing copolymerizable monomer in a proportion of 0.01 to 10.0 parts by weight, more preferably in a proportion of 0.5 to 7.0 parts by weight, particularly preferably in a proportion of 1.0 to 6.0 parts by weight.

The acrylic polymer used in the adhesive composition of this embodiment may be copolymerized with (B-2) a carboxyl group-containing copolymerizable monomer. (B-2) The carboxyl group-containing copolymerizable monomer is preferably selected from the group consisting of (meth)acrylic acid, carboxyethyl (meth)acrylate, carboxypentyl (meth)acrylate, and 2-(methyl)acrylate. Acryloxyethylhexahydrophthalic acid, 2-(meth)acryloxypropylhexahydrophthalic acid, 2-(meth)acryloxyethylhexahydrophthalic acid, 2 -(Meth)acryloxyethylsuccinic acid, 2-(meth)acryloxyethylmaleic acid, carboxypolycaprolactone mono(meth)acrylate, 2-(meth)propylene At least one or more of the compound group consisting of acyloxyethyl tetrahydrophthalic acid and the like. When copolymerizing (B-2) a carboxyl group-containing copolymerizable vinyl monomer, a total of 100 of at least one (meth)acrylate monomer having a carbon number of C1 to 18 relative to the (A) alkyl group The carboxyl group-containing copolymerizable vinyl monomer (B-2) is preferably contained in a proportion of 0.01 to 0.5 parts by weight, more preferably in a proportion of 0.01 to 0.4 parts by weight, and particularly preferably in a proportion of 0.01 to 0.3 parts by weight.

The preparation method of the acrylic polymer contained in the adhesive composition of this embodiment is not particularly limited, and suitable and conventional polymerization methods such as solution polymerization and emulsion polymerization can be used. The weight average molecular weight of the acrylic polymer copolymer is, for example, 500,000 to 3,000,000. The acid value of the acrylic polymer is preferably 0.1 to 1.0. The anti-pollution performance can thereby be improved. Here, the "acid value" is one of the indicators showing the acid content, and is expressed as the number of mg of potassium hydroxide required to neutralize 1 g of a carboxyl group-containing polymer.

The adhesive composition of this embodiment contains (F) an antistatic agent. The (F) antistatic agent of this embodiment is an ionic compound represented by the following general formula (1) and has a melting point of 25 to 80°C.

K ⁺ ‧A ^- (1) In the general formula (1), K ⁺ is a cation, and A ^- is a group selected from the group consisting of trifluoromethanesulfonate anion and pentafluoroethanesulfonate anion without acyl imine group. An anion in the group.

Preferably, the ionic compound is solid at normal temperature. Normal temperature is, for example, a temperature lower than 25°C. Specifically, an ionic compound that is solid at 23°C is preferred. The adhesive composition of this embodiment contains the ionic compound as an essential component in a proportion of 0.01 to 10 parts by weight relative to 100 parts by weight of the acrylic polymer.

The cation K ⁺ in the general formula (1) is preferably selected from the group consisting of pyridinium, imidazolium, phosphonium, sulfonium, pyrrolidinium, guanidinium, ammonium, isouronium, thiouronium, A cation in the group consisting of piperidinium, pyrazolium, methylium, and morpholinium.

Specific examples of the (F) antistatic agent include 1-octyl-2-methylpyridinium trifluoromethanesulfonate and 1,2,3-trimethylimidazolium pentafluoroethanesulfonic acid. Salt, 1-butyl-2,3-dimethylimidazolium trifluoromethanesulfonate, 1-hexyl-4-methylpyridinium pentafluoroethanesulfonate, 1-octyl-3-methyl Pyridinium trifluoromethanesulfonate, n-octylpyridinium trifluoromethanesulfonate, etc.

The adhesive composition of this embodiment further contains an isocyanate compound with a functionality of 3 or more as (C) a cross-linking agent. Examples of the isocyanate compound having a functionality of three or more include hexamethylene diisocyanate, isophorone diisocyanate, diphenylmethane diisocyanate, tolylene diisocyanate, xylylene diisocyanate, and the like. Biuret-modified bodies or isocyanurate-modified bodies of diisocyanates, adducts with trimethylol or higher polyhydric alcohols such as trimethylolpropane or glycerol, etc. The proportion of the isocyanate compound having trifunctionality or higher as the crosslinking agent (C) is, for example, preferably 0.1 to 10 parts by weight, more preferably 0.1 to 6 parts by weight relative to 100 parts by weight of the acrylic polymer. The proportion contains (C) cross-linking agent.

The adhesive composition of this embodiment may further contain (E) a keto-enol tautomer compound. (E) Keto-enol tautomer compounds include methyl acetoacetate, ethyl acetoacetate, octyl acetoacetate, oleyl acetoacetate, and lauryl acetoacetate. esters, β-ketoesters such as stearyl acetoacetate, or β-diketones such as acetoacetone, 2,4-hexanedione, and benzoylacetone. In an adhesive composition using a polyisocyanate compound as a cross-linking agent, these keto-enol tautomer compounds can inhibit blending and cross-linking by blocking the isocyanate group of the cross-linking agent. Excessive viscosity increase and gelation of the adhesive composition after treatment can extend the storage period of the adhesive composition. (E) The keto-enol tautomer compound is particularly preferably at least one selected from the group consisting of acetoacetone and ethyl acetoacetate. The (E) keto-enol tautomer compound is preferably contained in a proportion of 0.1 to 300 parts by weight relative to 100 parts by weight of the acrylic polymer.

The adhesive composition of this embodiment may further contain (D) a crosslinking accelerator of a metal chelate compound. When a polyisocyanate compound is used as a cross-linking agent, the cross-linking accelerator of the (D) metal chelate compound may function as a catalyst for the reaction (cross-linking reaction) between the copolymer and the cross-linking agent. Can. (D) The crosslinking accelerator of the metal chelate compound is a compound in which one or more polydentate ligands L are bonded to the central metal atom M. The metal chelate compound may or may not have one or more monodentate ligands X bonded to the metal atom M. Specific examples of the metal chelate compound include tris(2,4-pentanedione)iron(III), iron triacetylacetonate, titanium triacetylacetonate, ruthenium triacetylacetonate, and zinc diacetylacetonate. , aluminum triacetyl acetonate, zirconium tetraacetyl acetonate, tris(2,4-hexanedione)iron(III), bis(2,4-hexanedione)zinc, tris(2,4-hexanedione) Titanium, tris(2,4-hexanedione)aluminum, tetrakis(2,4-hexanedione)zirconium, etc.

(D) The crosslinking accelerator of the metal chelate compound is preferably at least one metal chelate compound selected from the group consisting of aluminum chelate compounds, titanium chelate compounds, and iron chelate compounds. The crosslinking accelerator containing (D) a metal chelate compound is preferably contained in a proportion of 0.001 to 0.5 parts by weight relative to 100 parts by weight of the acrylic polymer.

The (E) keto-enol tautomer compound has an effect of inhibiting cross-linking as opposed to the cross-linking accelerator of the (D) metal chelate compound, so it is preferable to appropriately set the (E) keto-enol tautomer compound The ratio of the crosslinking accelerator of the bulk compound to (D) the metal chelate compound. In order to extend the storage period of the adhesive composition and improve the storage stability, the weight part ratio of (E)/(D) is preferably 70 to 1000, more preferably 70 to 700, and particularly preferably 70 to 300. 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 adhesive composition of this embodiment may further contain (H) a polyether-modified siloxane compound as an optional component. (H) The polyether-modified siloxane compound is a siloxane compound with a polyether group. In addition to the usual siloxane unit [-SiR ¹ ₂ -O-], it also has a siloxane compound with a polyether group. Alkane unit [-SiR ¹ (R ² O(R ³ O) _n R ⁴ )-O-]. Here, R ¹ represents one or more alkyl groups or aryl groups, R ² and R ³ represent one or more alkylene groups, R ⁴ represents one or more alkyl groups or acyl groups, etc. ( terminal group). Examples of the polyether group include polyoxyalkylene groups such as polyoxyethylene groups [(C ₂ H ₄ O) _n ] and polyoxypropylene groups [(C ₃ H ₆ O) _n ]. In the siloxane unit having a polyether group, the end of the polyether group may be an OH group (R ⁴ =H in the above general formula (1)).

(H) The polyether-modified siloxane compound is preferably a polyether-modified siloxane compound with an HLB value of 6 to 12. In addition, it is preferable to contain 0.01 to 0.5 parts by weight, more preferably 0.02 to 0.35 parts by weight, and particularly preferably 0.02 to 0.25 parts by weight of (H) polyether modified silica based on 100 parts by weight of the acrylic polymer. Alkane compounds. The HLB value refers to the hydrophilic-lipophilic balance value (lipophilic to hydrophilic ratio) specified in, for example, JIS K3211 (surfactant terminology). The polyether-modified siloxane compound can be obtained, for example, by using a hydrosilylation reaction to graft an organic compound having an unsaturated bond and a polyoxyalkylene group onto the main body of a polyorganosiloxane having a hydrogenated siloxane group. chain. Specific examples include dimethylsiloxane-methyl(polyoxyethylidene)siloxane copolymer, dimethylsiloxane-methyl(polyoxyethylidene)siloxane-methane (polyoxypropylene) siloxane copolymer, dimethylsiloxane-methyl (polyoxypropylene) siloxane polymer, etc.

By blending the (H) polyether modified siloxane compound into the adhesive composition, the adhesion and reoperability of the adhesive layer can be improved. (H) The weight average molecular weight of the polyether-modified siloxane compound is preferably 10,000 or less. From the perspective of compatibility with acrylic polymers, although the compatibility is better when the HLB value is low and the molecular weight is low, when it is a polyether-modified siloxane compound with a low molecular weight, even if the HLB value is high and Even with slightly lower compatibility with polymers, excellent antistatic properties can be obtained.

The adhesive composition of this embodiment is not limited to the above-mentioned additives, and may also appropriately incorporate known surfactants, curing accelerators, plasticizers, fillers, curing retardants, processing aids, anti-aging agents, antioxidants, etc. of additives. These additives 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 a surface protective film bonded to a protective layer of a polarizer of a polarizing plate. Here, the protective layer of the polarizer of the polarizer may be one selected from the group consisting of TAC-based films, PMMA-based films, and PET-based films. Here, TAC is the abbreviation of cellulose triacetate, PMMA is the abbreviation of polymethylmethacrylate, and PET is the abbreviation of polyethylene terephthalate. In addition, the surface treatment performed on the surface of the protective layer of the polarizer of the polarizer may be one selected from the group consisting of untreated, AG treated, LR treated, AR treated, AG-LR treated, and AG-AR treated. . Here, AG refers to anti-glare (Anti Glare), LR refers to low reflection (Low Reflection), and AR refers to anti-reflection (Anti Reflection).

The adhesive layer formed by cross-linking the adhesive composition of this embodiment preferably has a surface resistivity of 1.0×10 ⁺¹² Ω/□ or less, more preferably 5.0×10 ⁺¹¹ Ω/□ or less. , particularly preferably 1.0×10 ⁺¹¹ Ω/□ or less. If the surface resistivity is high, the performance of releasing static electricity generated when peeling off the adhesive layer from the adherend is poor. Therefore, by making the surface resistivity sufficiently small, it is possible to reduce the peeling electrostatic voltage caused by the static electricity generated when peeling off the adhesive layer from the adherend, thereby suppressing the influence on the adherend.

The peeling electrostatic voltage of the adhesive layer formed by cross-linking the adhesive composition of this embodiment with respect to the low refractive index layer formed using the resin composition for forming the low refractive index layer containing fluoride It is preferably ±0.3kV or less, that is, it is preferably within the range of -0.3 to +0.3kV. Examples of the fluoride used in the composition for forming a low refractive index layer include one or more of fluorinated olefins, fluorinated vinyl ethers, fluorinated alkyl (meth)acrylates, and the like. Condensates of polymers such as fluorinated copolymers and silane compounds containing fluorinated alkyl groups. In addition to fluorinated monomers, unfluorinated monomers such as olefins, vinyl ethers, and (meth)acrylates may also be copolymerized in the fluorinated copolymer. The low refractive index layer may be combined with a high refractive index layer or the like to form an antireflection layer.

When measuring the peeling electrostatic voltage of the low refractive index layer, examples of base materials used to form the low refractive index layer on the surface include PMMA base materials and TAC base materials. In addition, the peeling electrostatic voltage of the adhesive layer formed by cross-linking the adhesive composition of this embodiment to the plane layer without any treatment on the surface of the PMMA base material and the TAC base material is preferably ±0.3 kV or less, that is, preferably Within the range of -0.3~+0.3kV.

It is preferred that after the adhesive layer is attached to the adherend, it is placed in an atmosphere with a temperature of 60°C and a humidity of 90% RH for 48 hours. The anti-pollution performance after being taken out of the atmosphere for 1 day is for the surface of the adherend. as "pollution-free". 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 subjected to low-reflection surface treatment with a composition containing fluoride. The fluoride-containing composition used for the low-reflection surface treatment may be the same as or different from the above-mentioned resin composition for forming the fluoride-containing low refractive index layer. Examples of the protective layer include PMMA base materials, TAC base materials, and the like.

The adhesive force of the adhesive layer formed by cross-linking the adhesive composition of this embodiment to the low refractive index layer applied to the surface of the PMMA base material is preferably at a low peeling speed of 0.3 m/min. The adhesive force is 0.04~0.2N/25mm. The adhesive force at a high-speed peeling speed of 30m/min is 2.0N/25mm or less. The adhesive force at a high-speed peeling speed of 30m/min is more preferably 0.2~1.6N/ 25mm. As a result, the change in adhesive force due to the peeling speed is small, and rapid peeling is possible even in the case of high-speed peeling. In addition, even when the surface protective film is temporarily peeled off for re-adhering, it does not require excessive force and can be easily peeled off from the adherend.

The gel fraction of the adhesive layer obtained by crosslinking the adhesive composition of this embodiment is preferably 95 to 100%, and more preferably 97 to 100%. Since the gel fraction of the adhesive layer is so high, the adhesive force will not become too large at low peeling speeds, and the dissolution of unpolymerized monomers or oligomers from the copolymer can be reduced, which can improve reoperation. properties and durability under high temperature and high humidity, and inhibits contamination of adherends.

The adhesive film of this embodiment is formed by forming an adhesive layer obtained by crosslinking the adhesive composition of this embodiment on one or both sides of a resin film. Moreover, the surface protective film of this embodiment is a surface protective film in which the adhesive layer which crosslinked the adhesive composition of this embodiment was formed on one side of a resin film. The adhesive composition of this embodiment has excellent antistatic properties, has an excellent balance of adhesive force at low peeling speeds and high peeling speeds, and further has anti-pollution properties. Therefore, it can be suitably used as a surface protective film of a polarizing plate.

As the base film of the adhesive layer or the release film (separation film) that protects the adhesive surface, a resin film such as a polyester film can be used. Antistatic treatment and antifouling treatment may be performed on one side of the resin film opposite to the side on which the adhesive layer is formed. Examples of the antistatic treatment include application of an antistatic agent, kneading, and the like. Examples of antifouling treatments include treatments using silicone-based, fluorine-based release agents or coating agents, silicon dioxide particles, and the like. You can also use polysilicone-based, fluorine-based, long-chain alkyl-based release agents, etc. to perform release treatment on the surface of the release film that is in contact with the adhesive surface of the adhesive layer.

Furthermore, by laminating an adhesive layer obtained by crosslinking the adhesive composition of the present embodiment on at least one surface of the optical film, an optical film with an adhesive layer can be obtained. Examples of optical films include polarizing films, retardation films, anti-reflection films, anti-glare films, ultraviolet absorption films, infrared absorption films, optical compensation films, brightness improvement films, and the like. Examples of equipment to which optical members are applied include liquid crystal panels, organic EL panels, touch panels, and the like. In the case of an optical surface protective film and an adhesive film such as a surface protective film for polarizers, it is preferable that the base film and the adhesive layer have sufficient transparency. Example

Hereinafter, the present invention will be specifically described through examples.

＜Preparation of acrylic polymer＞ [Example 1] Nitrogen gas was introduced into the reaction device equipped with a stirrer, a thermometer, a reflux condenser, and a nitrogen gas introduction pipe, and the air in the reaction device was replaced with nitrogen gas. Then, 100 parts by weight of 2-ethylhexyl acrylate, 6.0 parts by weight of 8-hydroxyoctyl acrylate, 0.1 parts by weight of acrylic acid, and a solvent (ethyl acetate) were added simultaneously to the reaction device. Then, 0.1 part by weight of azobisisobutyronitrile as a polymerization initiator was added dropwise over 2 hours, and the reaction was carried out at 65° C. for 6 hours, thereby obtaining the acrylic polymer used in Example 1. [Examples 2 to 6 and Comparative Examples 1 to 3] In the same manner as the above-mentioned acrylic polymer solution used in Example 1, except that the monomer compositions were adjusted to the descriptions in (A), (B-1), and (B-2) of Table 1, respectively, Acrylic polymer solutions used in Examples 2 to 6 and Comparative Examples 1 to 3 were obtained.

＜Manufacturing of adhesive composition and surface protective film＞ [Example 1] To the acrylic polymer solution of Example 1 prepared as described above, 2.5 parts by weight of a cross-linking agent (CORONATE HX) and 1.5 parts by weight of an antistatic agent (1-octyl-2-methylpyridinium trifluoride) were added. Methanesulfonate), 0.1 parts by weight of the cross-linking catalyst (titanium triacetyl acetonate) and 8.5 parts by weight of acetyl acetone were stirred and mixed to obtain the adhesive composition of Example 1. After the adhesive composition was coated on a release film (PET film coated with polysiloxane resin), the solvent was removed by drying at 90° C. to obtain an adhesive layer with a thickness of 20 μm. Then, transfer the adhesive layer with the release film to the surface of the base film (a PET film with antistatic and antifouling treatment on one side) opposite to the antistatic and antifouling surface. , the surface protection film of Example 1 having a laminated structure of "base film/adhesive layer/release film" was obtained. [Examples 2 to 6 and Comparative Examples 1 to 3] Except that the compositions of the additives were respectively adjusted to those described in (C) to (F) of Table 1, the surface protective films of Examples 2 to 6 and Comparative Examples 1 to 3 were obtained in the same manner as the above-mentioned Example 1. Surface protective film.

[Table 1]

In Table 1, the weight part of each component was calculated|required, assuming that the total number of (meth)acrylate monomers whose carbon number of the alkyl group (A) is C1-18 was 100 parts by weight. In addition, in Table 1, the acrylic polymer is assumed to be 100 parts by weight, and in each column (C) to (F), the content ratio (parts by weight) of each component is expressed by 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. In addition, CORONATE (registered trademark) HX, CORONATE HL and CORONATE L are trade names of TOSOH CORPORATION, and TAKENATE (registered trademark) D-140N, D-127N and D-110N are trade names of Mitsui Chemicals, Inc.

[Table 2]

Among (F) antistatic agents, F-1 to F-6 and F-9 are ionic compounds whose melting points are 25°C or more and 80°C or less and are solid at normal temperature. F-7 and F-8 are ionic compounds whose melting points exceed 80°C and are solid at normal temperature.

＜Test methods and evaluation＞ After the surface protective films in Examples 1 to 6 and Comparative Examples 1 to 3 were aged for 7 days in an atmosphere of 23° C. and 50% RH, they were evaluated by the following test method.

＜Test method for adhesion＞ Peel off the release film, and attach the surface protective film with the adhesive layer exposed to the surface of the polarizer through the adhesive layer. After leaving it for 1 day, perform an autoclave treatment at 50°C and 5 atmospheres for 20 minutes, and further heat it in the room. After leaving it at room temperature for 12 hours, it was used as a sample for measuring adhesion. Use a tensile testing machine to peel the test sample in the 180° direction at low speed (0.3m/min) or high speed (30m/min), and use the measured peel strength as the adhesive force. Here, the protective layer of the polarizer of the polarizer is selected from the group consisting of triacetyl cellulose (TAC), polymethyl methacrylate (PMMA), and polyethylene terephthalate (PET). kind of. In addition, for the LR polarizing plate and the AG-LR polarizing plate, a low-reflective surface treatment was performed on the surface of the protective layer of the polarizer of the polarizing plate using a composition containing fluoride.

＜Test method for surface resistivity＞ After curing the surface protective film and before attaching it to the polarizer, the release film was peeled off to expose the adhesive layer, and the resistivity of the adhesive layer was measured using a resistivity meter HIRESTA UP-HT450 (manufactured by Mitsubishi Chemical Analytech Co., Ltd.). Surface resistivity.

<Test method for peeling electrostatic voltage> Peel off the release film, and attach the surface protective film exposing the adhesive layer to a polarizing plate with a low refractive index layer formed by using a low refractive index layer containing fluoride on the adhered surface. formed from the composition. Using high-precision electrostatic sensors SK-035 and SK-200 (manufactured by KEYENCE CORPORATION), the voltage (electrostatic voltage) generated by charging the adherend when the surface protective film is peeled off 180° at a stretching speed of 30m/min is measured. The maximum value of the measured values was defined as the peeling electrostatic voltage.

＜Test method for anti-pollution performance＞ Using a laminating machine, the polarizing plate that has been subjected to low-reflection (LR) surface treatment is bonded to one side of the glass plate through an adhesive layer (double-sided adhesive tape). Then, a surface protection film is bonded to the surface of the polarizing plate using a bonding machine. After being attached to the adherend, place it in an atmosphere with a temperature of 60°C and a humidity of 90% RH for 48 hours. After being removed from the atmosphere for 1 day, peel off the surface protective film and visually observe the contamination status of the surface of the polarizer. Regarding the criteria for judging the anti-pollution performance, the surface of the polarizing plate is evaluated as "○" if there is no pollution, "△" if there is slight pollution, and "×" if there is pollution.

Table 3 shows the evaluation results of the surface protective films of Examples 1 to 6 and Comparative Examples 1 to 3. "Surface resistivity" is represented by writing "m×10 ⁺ⁿ " as "mE+n" (where m is an arbitrary real value and n is a positive integer). The "peeling electrostatic voltage" column indicates the material (TAC or PMMA) and surface treatment (Plain or AG-LR) of the protective layer of the polarizer of the polarizer used in the test. Plain in "surface treatment" means untreated. The "anti-pollution performance" column also indicates the material (PMMA) and surface treatment (AG-LR) of the protective layer of the polarizer used in the test.

[table 3]

The adhesion force of the surface protection films of Examples 1 to 6 to the polarizing plate as the adherend at a low peeling speed of 0.3m/min is 0.04~0.2N/25mm, and at a high peeling speed of 30m/min The adhesion force is below 2.0N/25mm, and the adhesion performance is excellent. In addition, the surface resistivity of the adhesive layer of the surface protective film of Examples 1 to 6 is 1.0×10 ⁺¹² Ω/□ or less, and the adhesive layer is formed using a composition for forming a low refractive index layer containing fluoride. The peeling electrostatic voltage of the low refractive index layer is in the range of -0.3~+0.3kV, and the antistatic performance is excellent. In addition, even for untreated PMMA base materials and TAC base materials without a low refractive index layer, the peeling electrostatic voltage of the adhesive layer of the surface protective film of Examples 1 to 6 is in the range of -0.3 to +0.3 kV. Excellent antistatic properties. Furthermore, after the surface protective films of Examples 1 to 6 were attached to the adherend, they were placed in an atmosphere with a temperature of 60°C and a humidity of 90% RH for 48 hours. After being taken out of the atmosphere for 1 day, the adherends were also treated. The polarizing plate that has undergone low-reflection surface treatment is free of contamination and has excellent anti-contamination performance. That is, the evaluation results shown in Table 3 regarding the surface protective films of Examples 1 to 6 confirmed that the technical problems of the present invention can be solved.

The surface protective film of Comparative Example 1 contains an antistatic agent with a melting point exceeding 80°C. Therefore, the adhesive layer of the surface protective film of Comparative Example 1 has high adhesive force, high peeling electrostatic voltage, and poor anti-pollution performance. In addition, the surface protective film of Comparative Example 2 contains an antistatic agent having a melting point exceeding 80°C. Therefore, the adhesive layer of the surface protective film of Comparative Example 2 has high adhesive force, high peeling electrostatic voltage, and poor anti-pollution performance. In addition, even though the melting point of the surface protective film of Comparative Example 3 is 25 to 80° C., it contains an antistatic agent whose anion has a amide group. Therefore, the surface protective film of Comparative Example 3 has a high peeling electrostatic voltage against the PMMA substrate and poor anti-pollution performance. As mentioned above, the surface protective films of Comparative Examples 1 to 3 failed to solve the technical problems of the present invention.

without.

without.

Claims (10)

An adhesive composition, which is an adhesive composition containing an acrylic polymer, (F) antistatic agent and (C) cross-linking agent, characterized in that the (F) antistatic agent has a melting point of 25~ 80°C ionic compound, the ionic compound is selected from the group consisting of 1-octyl-2-methylpyridinium trifluoromethanesulfonate, 1,2,3-trimethylimidazolium pentafluoroethanesulfonate, 1 -Butyl-2,3-dimethylimidazolium trifluoromethanesulfonate, 1-hexyl-4-methylpyridinium pentafluoroethanesulfonate, 1-octyl-3-methylpyridinium trifluoromethanesulfonate One or more types of the group consisting of fluoromethanesulfonate and n-octylpyridinium trifluoromethanesulfonate, the acrylic polymer being an acrylic polymer having a glass transition temperature of 0°C or lower, relative to 100 parts by weight of the acrylic polymer contains the ionic compound as an essential component in a ratio of 0.01 to 10 parts by weight. The adhesive composition as described in item 1 of the patent application, wherein the acrylic polymer is: a (meth)acrylate monomer with a carbon number of C1 to 18 relative to the (A) alkyl group. The total amount of at least one or more kinds of hydroxyl group-containing copolymerizable vinyl monomers is 100 parts by weight, and the proportion of at least one or more kinds of hydroxyl-containing copolymerizable vinyl monomers in (B-1) is 0.01 to 10 parts by weight in total, and/or it is contained in (B-2) An acrylic polymer of a copolymer obtained by copolymerizing at least one type of carboxyl copolymerizable vinyl monomer in a total proportion of 0.01 to 0.5 parts by weight, wherein the number of carbon atoms in the (A) alkyl group is C1 At least one or more of the (meth)acrylate monomers of ~18, containing at least one selected from the group consisting of isooctyl (meth)acrylate and isononyl (meth)acrylate in a proportion of more than 50 parts by weight per 100 parts by weight in total. , at least one of the group consisting of 2-ethylhexyl (meth)acrylate, containing an isocyanate compound with a functionality of 3 or more in a proportion of 0.1 to 10 parts by weight relative to 100 parts by weight of the acrylic polymer. As the (C) cross-linking agent, The adhesive composition further contains (D) a cross-linking accelerator of a metal chelate compound and (E) a keto-enol tautomer compound. The adhesive composition as described in claim 2, wherein the adhesive layer formed by cross-linking the adhesive composition has a surface resistivity of 1.0×10 ⁺¹² Ω/□ or less, and the adhesive layer The peeling electrostatic voltage of the agent layer on the low refractive index layer formed on the surface of the PMMA base material and the TAC base material using the resin composition for forming the low refractive index layer containing fluoride, and the peeling electrostatic voltage on the PMMA base material and the TAC base material The peeling electrostatic voltage of the flat layer without any surface treatment is below ±0.3kV. After the adhesive layer is attached to the adherend, it is placed for 48 hours in an atmosphere with a temperature of 60°C and a humidity of 90%RH. The anti-pollution performance after being taken out in the above atmosphere for 1 day is "no pollution" for the surface of the adherend. The adherend is a protective layer laminated on the polarizer and protected by a composition containing fluoride. A polarizing plate with a low-reflective surface treatment on the surface of the layer. Regarding the adhesion of the adhesive layer to the low refractive index layer applied to the surface of the PMMA base material, at a low peeling speed of 0.3m/min The adhesive force is 0.04~0.2N/25mm, and the adhesive force at a high-speed peeling speed of 30m/min is less than 2.0N/25mm. The adhesive composition as described in item 2 or 3 of the patent application, wherein the (B-1) hydroxyl-containing copolymerizable vinyl monomer is selected from the group consisting of 8-hydroxyoctyl (meth)acrylate, (meth)acrylate 6-hydroxyhexyl methacrylate, 4-hydroxybutyl (meth)acrylate, 2-hydroxyethyl (meth)acrylate, N-hydroxy(meth)acrylamide, N-hydroxymethyl(meth)acrylate (B-2) The carboxyl group-containing copolymerizable vinyl monomer is selected from the group consisting of (methyl) acrylamide and N-hydroxyethyl (meth) acrylamide. acrylic acid, carboxyethyl (methane acrylate, carboxypentyl (meth)acrylate, 2-(meth)acryloxyethylhexahydrophthalic acid, 2-(meth)acryloxypropylhexahydrophthalic acid Dicarboxylic acid, 2-(meth)acryloxyethyl phthalic acid, 2-(meth)acryloxyethyl succinic acid, 2-(meth)acryloxyethyl maleic acid , at least one or more compounds in the group consisting of carboxypolycaprolactone mono(meth)acrylate and 2-(meth)acryloyloxyethyltetrahydrophthalic acid. The adhesive composition as described in item 2 or 3 of the patent application, wherein the adhesive composition contains the ( D) Cross-linking accelerator for metal chelate compounds, and contains the (E) keto-enol tautomer compound in a proportion of 0.1 to 300 parts by weight, and the cross-linking accelerator of the (D) metal chelate compound The agent is at least one selected from the group consisting of aluminum chelate compounds, titanium chelate compounds, and iron chelate compounds, and the weight ratio of (E)/(D) is 70 to 1000. An adhesive film characterized in that an adhesive layer formed by cross-linking the adhesive composition described in any one of items 1 to 5 of the patent application is laminated on one side of a resin film. A surface protection film using the adhesive film described in Item 6 of the patent application. A surface protective film for polarizers using the adhesive film described in Item 6 of the patent application. An optical film with an adhesive layer, wherein an adhesive obtained by cross-linking the adhesive composition described in any one of items 1 to 5 of the patent application is laminated on at least one side of the optical film. layer. The adhesive film according to claim 6, wherein an antistatic treatment and an antifouling treatment are performed on one side of the resin film opposite to the side on which the adhesive layer is formed.