KR20200035829A - Adhesive composition - Google Patents

Abstract

Provided are an adhesive composition capable of achieving both antistatic performance and anti-pollution performance while having excellent adhesion performance including a balanced adhesion in a low-speed peeling speed and a high-speed peeling speed, and an adhesive film and a surface protection film using the same. The adhesive composition comprises an acrylic polymer, an antistatic agent (F), and a cross-linker (C), wherein the antistatic agent (F) is an ionic compound having a melting point of 25-80°C and represented by chemical formula (1) K^+ · A^- [where K^+ is one cation selected from the group consisting of pyridinium, imidazolium, phosphonium, sulfonium, pyrrolidinium, guanidinium, ammonium, isouronium, thiuronium, piperidinium, pyrazolium, methylium, and morpholinium, and A^- is one anion selected from the group consisting of trifluoromethanesulfonate and pentafluoroethanesulfonate which do not contain an imide group], and the ionic compound is contained in a proportion of 0.01-10 parts by weight based on 100 parts by weight of an acrylic polymer.

Description

Adhesive composition {ADHESIVE COMPOSITION}

The present invention relates to an adhesive composition containing an antistatic agent, an adhesive film using the same, and a surface protection film. More specifically, at a low-speed peeling speed and a high-speed peeling speed, an adhesive composition capable of achieving both antistatic performance and fouling resistance performance together with excellent adhesive performance such as having a balanced adhesive force, and an adhesive film using the adhesive composition, It relates to providing a surface protection film.

Conventionally, in the manufacturing process of an optical member, such as a polarizing plate, which is a member constituting a liquid crystal display, a surface protection film for temporarily protecting the surface of the optical member is pasted. This surface protection film is used only in the process of manufacturing the optical member, and is removed by peeling from the optical member at the time of attaching the optical member to the 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, it may be called a process film in general.

In this way, the surface protection film used in the process of manufacturing the optical member is provided with an adhesive layer on one side of a polyethylene terephthalate (PET) resin film having optical transparency. In order to protect the pressure-sensitive adhesive layer until the surface protection film is pasted to the optical member, the release film subjected to the release treatment is pasted on the surface of the pressure-sensitive adhesive layer.

Then, an optical member such as a polarizing plate is subjected to a product inspection that involves optical evaluation such as display ability, color, contrast, foreign matter mixing, etc. of the liquid crystal display panel while the surface protection film is stuck. For this reason, as the required performance for the surface protective film, it is required that air bubbles, foreign substances, and low-molecular-weight components of the pressure-sensitive adhesive composition are not adhered to the pressure-sensitive adhesive layer, that is, have contamination resistance.

In addition, when peeling the surface protection film from an optical member such as a polarizing plate, it is feared that peeling charges generated by static electricity generated when the pressure-sensitive adhesive layer and the adherend peel off affect the failure of the electric control circuit of the liquid crystal display. For this reason, the pressure-sensitive adhesive layer of the surface protection film is required to have excellent 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 conventionally used triacetyl cellulose (TAC), acrylic resins such as polymethyl methacrylate (PMMA), polyethylene terephthalate (PET), etc. The use of materials that are liable to cause peeling electrification when peeling the surface protective film of the polarizing plate, such as polyester-based resins, cyclic olefin polymers, and polycarbonates, is expanding. For this reason, it is required that the antistatic performance required for the pressure-sensitive adhesive layer for the surface protective film of the polarizing plate is superior to that of the prior art.

Moreover, when peeling a surface protection film from an optical member, such as a polarizing plate, finally, it is calculated | required that it can peel quickly. So-called peeling force is required to have little change in peeling speed due to peeling speed so that peeling can be performed quickly even by high-speed peeling.

As described above, in recent years, with respect to the pressure-sensitive adhesive layer constituting the surface protection film, (1) having a balance of adhesion at low-speed peeling speed and high-speed peeling speed, (2) having fouling resistance, (3) excellent charging What has a preventive performance etc. is calculated | required from the point of the ease of use in using a surface protection film.

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

In order to solve such a problem, for example, (1) having a balance of adhesion in low-speed peeling speed and high-speed peeling speed, (2) having fouling resistance, and (3) having excellent antistatic performance For each, the following proposals are known.

(1) Regarding having a balance of adhesive strength at a low-speed peeling speed and a high-speed peeling speed, a copolymer of a (meth) acrylic acid alkyl ester having an alkyl group having 7 or less carbon atoms and a carboxyl group-containing copolymerizable compound is a main component, and this is a crosslinking agent. In the acrylic pressure-sensitive adhesive layer formed by crosslinking with, there is a problem that, when adhered for a long period of time, adhesion of the pressure-sensitive adhesive to the adherend side occurs, and the synergism of the adhesive force with respect to the adherend is large. To avoid this, it is known to use a copolymer of a (meth) acrylic acid alkyl ester having an alkyl group having 8 to 10 carbon atoms and a copolymerizable compound having an alcoholic hydroxyl group, and to form an adhesive layer cross-linked with a crosslinking agent ( Patent Document 1).

In addition, a small amount of a copolymer of a copolymer of a (meth) acrylic acid alkyl ester and a carboxyl group-containing copolymerizable compound is prepared in the same copolymer as described above, and a crosslinked adhesive layer has been proposed. However, these are used for protecting surfaces such as a plastic plate having a smooth surface due to low surface tension, causing problems such as exfoliation due to heating during processing or preservation, or ashing at high speed, which is a manual work area. There was also a problem that the peelability was poor.

In order to solve these problems, a) 100 parts by weight of (meth) acrylic acid alkyl ester mainly composed of (meth) acrylic acid alkyl ester having an alkyl group having 8 to 10 carbon atoms, b) 1 to 15 weight of carboxyl-containing copolymerizable compound A pressure-sensitive adhesive composition containing a crosslinking agent equal to or greater than the equivalent of the carboxyl group of the component b) in a copolymer of a monomer mixture comprising parts and c) 3 to 100 parts by weight of a vinyl ester of an aliphatic carboxylic acid having 1 to 5 carbon atoms It has been proposed (Patent Document 2).

In the pressure-sensitive adhesive composition described in Patent Literature 2, there is no occurrence of peeling phenomenon such as excitation during processing or storage, and the rise in adhesive strength over time is small, resulting in excellent removability, and long-term storage, especially long-term storage under a high temperature atmosphere It is said that it can be peeled off with a small force, does not generate an adhesive residue on the adherend at that time, and can be peeled off with a small force even when high-speed peeling is performed.

However, in the pressure-sensitive adhesive composition described in Patent Document 2, since the gel fraction of the pressure-sensitive adhesive layers 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 the antistatic performance and the anti-pollution performance, and it is difficult to form a pressure-sensitive adhesive layer having excellent anti-static and anti-pollution performance when a material that is prone to peeling electrification is used as an adherend. there was.

Moreover, as for (2) having pollution resistance, 0 mass parts or more and less than 0.5 mass parts of carboxyl group-containing monomers, 0.6-9 mass parts of hydroxy group-containing (meth) acrylic monomers, and 99.4-90.5 mass parts of (meth) acrylic acid ester monomers 100 parts by weight of a (meth) acrylic copolymer having a weight average molecular weight of 100,000 or more and less than 1 million; And an adhesive composition comprising 0.1 to 5 parts by mass of a carbodiimide-based crosslinking agent (Patent Document 3).

In the pressure-sensitive adhesive composition described in Patent Document 3, a carbodiimide-based crosslinking agent is used as a crosslinking agent for a (meth) acrylic copolymer having a specific composition. For this reason, it is possible to form a crosslinked structure in the pressure-sensitive adhesive layer that can follow shrinkage due to pressure and temperature during autoclave treatment. For this reason, the pressure-sensitive adhesive layer formed using the pressure-sensitive adhesive composition described in Patent Literature 3 can suppress and prevent foaming even under high temperature and high pressure conditions (at the time of autoclave treatment), and has excellent stain resistance and excellent transparency. It is done.

However, in the pressure-sensitive adhesive composition described in Patent Document 3, the stain resistance performance is improved, but it is not possible to realize that the anti-static performance is compatible with the excellent adhesion performance, and it remains as a further problem to be solved.

In addition, as for the method having (3) excellent antistatic performance, as a method for imparting antistatic property to the surface protective film, a method of incorporating an antistatic agent in a base film is known. As the antistatic agent, for example, (a) various cationic antistatic agents having cationic groups such as quaternary ammonium salts, pyridinium salts and primary to tertiary amino groups, (b) sulfonate groups, sulfate ester bases, phosphoric acid Anionic antistatic agents having anionic groups such as ester bases and phosphonate groups, (c) amphoteric antistatic agents such as amino acid-based and aminosulfuric acid ester-based, (d) ratios of amino alcohol-based, glycerin-based, polyethylene glycol-based An ionic antistatic agent, (e) a polymer antistatic agent having a high molecular weight of the antistatic agent as described above, and the like are disclosed (Patent Document 4).

However, in the surface protection film described in Patent Document 4, although there is a description regarding imparting antistatic performance related to adhesion of foreign substances to an adherend, means for achieving both excellent adhesion performance and fouling resistance are not described. It remains as a task to be solved.

In addition, in recent years, it has been proposed to contain an antistatic agent in the base film, or to include an antistatic agent in the pressure-sensitive adhesive layer directly without being applied to the surface of the base film. For example, an antistatic pressure-sensitive adhesive composition is disclosed, wherein a salt having an anion having a fluoro group and a sulfonyl group is dispersed in a state dissolved 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 Literature 5, an ester formed of a mono or dicarboxylic acid having a saturated or unsaturated acyclic hydrocarbon group as a plasticizer, and an alcohol having an acyclic hydrocarbon group having 1 to 20 carbon atoms, or in the unsaturated acyclic hydrocarbon group It has been disclosed to use plasticizers consisting of esters in which the unsaturated groups are epoxidized. 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 adhesive composition, Since the plasticizer is preferably retained in the plasticizer acrylic antistatic adhesive composition, it is said that bleed-out is suppressed.

However, the antistatic pressure-sensitive adhesive composition described in Patent Document 5 discloses that antistatic performance and bleed-out improvement techniques are disclosed, but excellent adhesion performance such as balance of low-speed peeling speed and high-speed peeling power is obtained. There is no, and there remains a problem of obtaining an adhesive composition having excellent adhesive performance.

Japanese Patent Application Publication No. 63-225677 Japanese Patent Publication No. Hei 11-256111 Japanese Patent Application Publication No. 2011-122054 Japanese Patent Application Publication No. Hei 11-070629 Japanese Patent Publication No. 2014-118469

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

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

Furthermore, in recent years, the types of adherend materials to which the surface protective film is bonded have increased, and since the surface treatment of adherends is also multifaceted, it is more difficult to simultaneously express the anti-pollution and anti-static properties for all adherends. ought.

The present invention has been made in view of the above circumstances, and an adhesive composition capable of achieving both antistatic performance and fouling resistance performance together with excellent adhesive performance such as having a balanced adhesive force in a low-speed peeling speed and a high-speed peeling speed, and An object is to provide an adhesive film and a 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 a solid phase at room temperature with a trifluoromethanesulfonate anion or a pentafluoroethanesulfonate anion having a melting point of 25 to 80 ° C. It has been found that the antistatic performance and the pollution resistance performance can be simultaneously expressed, 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 that is a solid phase at room temperature with a cation selected from the group consisting of methyllium, morpholinium, and a trifluoromethanesulfonate anion or a pentafluoroethanesulfonate anion, and using the same The adhesive film and the surface protection film are capable of realizing both antistatic performance and fouling 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 is an adhesive composition containing an acrylic polymer, (F) an antistatic agent, and (C) a crosslinking agent, wherein the (F) antistatic agent is represented by the following formula (1): ℃ is an ionic compound,

K ⁺ · A ^- (1)

[In the formula (1), K ⁺ is pyridinium, imidazolium, phosphonium, sulfonium, pyrrolidinium, guanidinium, ammonium, isouronium, thiuronium, piperidinium, pyrazolium, methylium , Is a type of cation selected from the group consisting of morpholinium, and A ^- is a type of anion selected from the group consisting of trifluoromethanesulfonate anion that does not contain an imide group, and pentafluoroethanesulfonate anion. ]

The acrylic polymer is an acrylic polymer having a glass transition point temperature of 0 ° C. or less, and an adhesive composition comprising 100 parts by weight of the acrylic polymer containing the ionic compound as an essential component in a proportion of 0.01 to 10 parts by weight. to provide.

At least one or more of the copolymerizable vinyl monomer containing a hydroxyl group (B-1) with respect to 100 parts by weight of the at least one or more of the (meth) acrylic acid ester monomers in which the acrylic polymer has (C) C1 to C18 of the alkyl group. A total of 0.01 to 10 parts by weight, and / or (B-2) an acrylic polymer of a copolymer obtained by copolymerizing a total of at least one of copolymerizable vinyl monomers containing a carboxyl group at a ratio of 0.01 to 0.5 parts by weight, wherein ( A) Among 100 parts by weight of at least one or more of (meth) acrylic acid ester monomers having C1 to 18 carbon atoms in the alkyl group, isooctyl (meth) acrylate, isononyl (meth) acrylate, 2-ethylhexyl (meth) acrylic It is made by containing at least one selected from the group consisting of a ratio in a proportion of 50 parts by weight or more, and with respect to 100 parts by weight of the acrylic polymer, the (C) crosslinking agent is a trifunctional or more Cyano is accomplished by containing a proportion from 0.1 to 10 parts by weight of the carbonate compound, preferably a crosslinking accelerator in the adhesive composition are added in (D) a metal chelate compound, comprising a compound all tautomeric keto Yen (E).

The resin composition for forming a low-refractive-index layer containing a fluorine compound on the surfaces of the PMMA substrate and the TAC substrate of the pressure-sensitive adhesive layer having a surface resistivity of 1.0 × 10 ^{+ 12} Ω / □ or less, wherein the pressure-sensitive adhesive layer is crosslinked, is used. The peeling voltage for the formed low-refractive-index layer, and the peeling voltage for the plain layer which has no treatment on the surfaces of the PMMA substrate and the TAC substrate are both ± 0.3 MPa or less, and the pressure-sensitive adhesive layer provides a protective layer to the polarizer. After lamination, and the surface of the protective layer was adhered to an adherend which is a polarizing plate treated with a low-reflection surface with a composition containing a fluorine compound, the mixture was left under an atmosphere of 60 ° C at a temperature of 90% RH for 48hr, taken out from the above atmosphere for 1 day. The post-pollution resistance is "no contamination" with respect to the surface of the adherend, and the adhesive strength of the pressure-sensitive adhesive layer to the low-refractive-index layer applied to the surface of the PMMA substrate is low. It is preferable that the adhesive strength at a peeling rate of 0.3 m / min is 0.04 to 0.2 N / 25 mm, and the adhesive strength at a high speed peeling speed of 30 m / min is 2.0 N / 25 mm or less.

The (B-1) 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 of compounds consisting of hydroxyethyl (meth) acrylate, N-hydroxy (meth) acrylamide, N-hydroxymethyl (meth) acrylamide, and N-hydroxyethyl (meth) acrylamide ego,

The (B-2) copolymerizable vinyl monomer containing a carboxyl group is (meth) acrylic acid, carboxyethyl (meth) acrylate, carboxypentyl (meth) acrylate, 2- (meth) acryloyloxyethyl hexahydrophthalic acid, 2- (meth) acryloyloxypropylhexahydrophthalic acid, 2- (meth) acryloyloxyethylphthalic acid, 2- (meth) acryloyloxyethylsuccinic acid, 2- (meth) acryloyloxyethylmaleic acid , It is preferable that it is at least 1 sort (s) or more selected from the compound group which consists of carboxy polycaprolactone mono (meth) acrylate and 2- (meth) acryloyloxyethyl tetrahydrophthalic acid.

The pressure-sensitive adhesive composition in a proportion of 0.001 to 0.5 parts by weight of the cross-linking accelerator of the (D) metal chelate compound, and 0.1 to 300 parts by weight of the (E) ketoenol tautomer compound relative to 100 parts by weight of the acrylic polymer. It is made to contain, and the crosslinking accelerator of the metal chelate compound (D) is at least one selected from the group consisting of aluminum chelate compounds, titanium chelate compounds, and iron chelate compounds, and parts by weight of (E) / (D) It is preferable that the ratio is 70 to 1000.

In addition, the present invention provides a pressure-sensitive adhesive film characterized in that the pressure-sensitive adhesive layer cross-linking 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 using the adhesive film.

In addition, the present invention provides an optical film having an adhesive layer on which an adhesive layer cross-linking the adhesive composition is formed on at least one side of the optical film.

In addition, the present invention provides an adhesive film on one side of the resin film, on the opposite side to which the pressure-sensitive adhesive layer is formed, on which an antistatic treatment and an antifouling treatment are applied.

The pressure-sensitive adhesive composition according to the present invention has excellent adhesion performance and does not deteriorate over time and has excellent anti-peeling performance compared to the pressure-sensitive adhesive composition for a conventional 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, it has excellent adhesion performance and does not deteriorate with time, has excellent peeling antistatic performance, and has a remarkable effect on both antistatic performance and fouling resistance.

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

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

The pressure-sensitive adhesive composition of the present embodiment is an pressure-sensitive adhesive composition containing an acrylic polymer, (F) an antistatic agent, and (C) 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). Sex compound,

K ⁺ · A ^- (1)

[In the formula (1), K ⁺ is pyridinium, imidazolium, phosphonium, sulfonium, pyrrolidinium, guanidinium, ammonium, isouronium, thiuronium, piperidinium, pyrazolium, methylium , Is a type of cation selected from the group consisting of morpholinium, and A ^- is a type of anion selected from the group consisting of a trifluoromethanesulfonate anion that does not contain an imide group, and a pentafluoroethanesulfonate anion. ]

The acrylic polymer is an acrylic polymer having a glass transition point temperature of 0 ° C. or less, and is characterized by containing the ionic compound as an essential component in a proportion of 0.01 to 10 parts by weight with respect to 100 parts by weight of the acrylic polymer.

The acrylic polymer used in the pressure-sensitive adhesive composition of the present embodiment is the main polymer of the pressure-sensitive adhesive composition, and is an acrylic polymer having a glass transition point temperature of 0 ° C or lower. Further, the acrylic polymer is preferably a copolymer comprising (A) an alkyl group having a (meth) acrylic acid ester monomer having C1 to 18 carbon atoms as a main component.

(A) Examples of the (meth) acrylic acid ester monomer having C1 to 18 carbon atoms in the alkyl group include methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, butyl (meth) acrylate, and 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) Acrylate, etc. The can. 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 comprises (A) 100 parts by weight of at least one or more of (meth) acrylic acid ester monomers having 1 to 18 carbon atoms in the alkyl group, 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, and 75 It is particularly preferable to contain it in a proportion of parts by weight or more.

The acrylic polymer used in the pressure-sensitive adhesive composition of the present embodiment includes (B-1) at least one 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. The acrylic polymer may be copolymerized with at least one of a copolymerizable vinyl monomer (B-1) containing a hydroxyl group and a copolymerizable vinyl monomer containing a (B-2) carboxyl group, and both may be copolymerized.

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

You may copolymerize (B-1) the copolymerizable monomer containing a hydroxyl group in 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 member selected from the group of compounds consisting of hydroxyethyl (meth) acrylate, N-hydroxy (meth) acrylamide, N-hydroxymethyl (meth) acrylamide, and N-hydroxyethyl (meth) acrylamide. It is preferable that it is above.

(B-1) In the case of copolymerizing a copolymerizable monomer containing a hydroxyl group, (B-1) based on 100 parts by weight of at least one or more of (meth) acrylic acid ester monomers having C1 to 18 carbon atoms in the alkyl group, (B-1) It is preferable that the copolymerizable monomer containing a hydroxyl group is contained in a proportion of 0.01 to 10.0 parts by weight, more preferably 0.5 to 7.0 parts by weight, and particularly preferably 1.0 to 6.0 parts by weight. Do.

You may copolymerize the copolymerizable monomer containing a (B-2) carboxyl group in 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) acryloyloxyethyl hexahydrophthalic acid, 2- (meth) acryloyloxypropylhexahydrophthalic acid, 2- (meth) acryloyloxyethylphthalic acid, 2- (meth) acryloyloxyethylsuccinic acid, 2- (meth) acryloyloxyethylmaleic acid , It is preferable that it is at least 1 sort (s) or more selected from the compound group which consists of carboxy polycaprolactone mono (meth) acrylate, 2- (meth) acryloyloxyethyl tetrahydrophthalic acid, etc.

(B-2) When copolymerizing a copolymerizable vinyl monomer containing a carboxyl group, (A) 0.01 to 0.5 weight based on 100 parts by weight of at least one or more of (meth) acrylic acid ester monomers having C1 to 18 carbon atoms in the alkyl group. It is preferably made to contain in a proportion of parts, more preferably made to contain in a proportion of 0.01 to 0.4 parts by weight, and particularly preferably made to contain in a proportion of 0.01 to 0.3 parts by weight.

The manufacturing method of the acrylic polymer contained in the adhesive composition which concerns on this embodiment is not specifically limited, A well-known polymerization method can be used suitably, such as a solution polymerization method and an emulsion polymerization method. The weight average molecular weight of the copolymer of the acrylic polymer is, for example, 500,000 to 3 million. It is preferable that the acid value of acrylic polymer is 0.1-1.0. For this reason, the fouling resistance performance can be improved. Here, the "acid value" is one of the indices indicating the content of the acid, and is represented by the number of mg of potassium hydroxide required to neutralize 1 g of a 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 formula (1).

K ⁺ · A ^- (1)

[In the formula (1), K ⁺ is pyridinium, imidazolium, phosphonium, sulfonium, pyrrolidinium, guanidinium, ammonium, isouronium, thiuronium, piperidinium, pyrazolium, methylium , Is a type of cation selected from the group consisting of morpholinium, and A ^- is a type of anion selected from the group consisting of trifluoromethanesulfonate anion that does not contain an imide group, and pentafluoroethanesulfonate anion. ]

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

(F) Specific examples of the antistatic agent include, for example, 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 And sulfonate salts and n-octylpyridinium trifluoromethanesulfonate salts.

The pressure-sensitive adhesive composition according to the present embodiment also contains a trifunctional or higher isocyanate compound as the crosslinking agent (C). Examples of the trifunctional or higher isocyanate compound include, for example, a burette-modified product of diisocyanates such as hexamethylene diisocyanate, isophorone diisocyanate, diphenylmethane diisocyanate, tolylene diisocyanate, and xylylene diisocyanate, and isocyanurate modification. And adducts with trivalent or higher polyols such as sieves, trimethylolpropane, and glycerin. (C) As a ratio of the trifunctional or higher isocyanate compound which is a crosslinking agent, it is preferable to contain it in the ratio of 0.1-10 weight part with respect to 100 weight part of acrylic polymers, for example, and to contain it in the ratio of 0.1-6 weight part. It is more preferable.

The pressure-sensitive adhesive composition according to the present embodiment may contain (E) a ketoenol tautomeric compound. (E) Ketoenol tautomeric compounds include β-ketoesters such as methyl acetoacetate, ethyl acetoacetate, octyl acetoacetate, oleyl acetoacetate, lauryl acetoacetate, and stearyl acetoacetate, acetylacetone, 2 And β-diketones such as, 4-hexanedione and benzoyl acetone. In the pressure-sensitive adhesive composition comprising a polyisocyanate compound as a crosslinking agent, by blocking the isocyanate group possessed by the crosslinking agent, excessive viscosity increase and gelation of the pressure-sensitive adhesive composition after the crosslinking agent can be suppressed, and the pot life of the pressure-sensitive adhesive composition can be extended. (E) The ketoenol tautomeric compound is particularly preferably at least one selected from the group consisting of acetylacetone and ethyl acetoacetate. It is preferable to contain the (E) ketoenol tautomeric compound in a proportion of 0.1 to 300 parts by weight with respect to 100 parts by weight of the acrylic polymer.

The pressure-sensitive adhesive composition according to the present embodiment may contain (D) a crosslinking accelerator of the metal chelate compound. (D) When the crosslinking accelerator of the metal chelate compound is a polyisocyanate compound, a substance that functions as a catalyst for the reaction (crosslinking reaction) between the copolymer and the crosslinking agent may be used. (D) The crosslinking accelerator of the metal chelate compound is a compound in which one or more polydentate ligands L are bound to the central metal atom M. The metal chelate compound may or may not have one or more monodentate ligands X that bind 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, and aluminum tris Acetylacetonate, zirconium tetrakisacetylacetonate, tris (2,4-hexanedionate) iron (III), bis (2,4-hexanedionate) zinc, tris (2,4-hexanedionate) titanium, And tris (2,4-hexanedionate) aluminum, tetrakis (2,4-hexanedionate) zirconium, and the like.

(D) As a crosslinking accelerator of a metal chelate compound, it is preferable that it is at least 1 or more types of metal chelate compounds selected from the group which consists of an aluminum chelate compound, a titanium chelate compound, and an iron chelate compound. It is preferable that the crosslinking accelerator of the metal chelate compound (D) is contained in a proportion of 0.001 to 0.5 parts by weight with respect to 100 parts by weight of the acrylic polymer.

(E) The ketoenol tautomeric compound has the effect of inhibiting crosslinking as opposed to the crosslinking accelerator of (D) the metal chelate compound, and (E) the ketoenol tautomeric compound and (D) the metal chelate compound. It is preferable to properly set the proportion of the crosslinking accelerator. In order to lengthen the pot life of the pressure-sensitive adhesive composition and improve storage stability, the ratio by weight of (E) / (D) is preferably 70 to 1000, more preferably 70 to 700, and 70 to 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 usual 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 two or more alkyl groups or aryl groups, R ² and R ³ are one or two or more alkylene groups, R ⁴ is one or two or more alkyl groups or acyl groups (terminal groups). Shows. 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 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, it is preferable that (H) the polyether-modified siloxane compound is contained in an amount of 0.01 to 0.5 parts by weight, more preferably 0.02 to 0.35 parts by weight, and more preferably 0.02 to 0.25 parts by weight, based on 100 parts by weight of the acrylic polymer. It is particularly preferred. The HLB value is, for example, a hydrophilic lipophilic balance (hydrophilic lipophilic ratio) specified in JIS K3211 (surfactant term) or the like.

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

(H) By blending the polyether-modified siloxane compound with the pressure-sensitive adhesive composition, the pressure-sensitive adhesive layer and the rework performance of the pressure-sensitive adhesive layer can be improved. (H) The weight average molecular weight of the polyether-modified siloxane compound is preferably 10000 or less. From the viewpoint of compatibility with the acrylic polymer, the HLB value is low and the molecular weight is lower, the compatibility is good, but if the polyether-modified siloxane compound having a low molecular weight, the HLB value is relatively high, and the antistatic property is excellent even if the compatibility with the polymer is slightly low. This is obtained.

The pressure-sensitive adhesive composition of the present embodiment is not limited to the above-described additives, and well-known additives such as surfactants, curing accelerators, plasticizers, fillers, curing retarders, processing aids, anti-aging agents, and antioxidants may be suitably blended. These may be used alone or in combination of two or more.

The pressure-sensitive adhesive composition of the present embodiment is preferable as the pressure-sensitive adhesive composition for a surface protective film bonded to the polarizer protective layer of the polarizing plate. Here, one type selected from the group consisting of a TAC-based film, a PMMA-based film, and a PET-based film may be mentioned. Here, TAC is an abbreviation of triacetyl cellulose, PMMA is polymethyl methacrylate, and PET is 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 untreatment, 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.

In the pressure-sensitive adhesive layer in which the pressure-sensitive adhesive composition of the present embodiment is crosslinked, the surface resistivity of the pressure-sensitive adhesive layer is preferably 1.0 × 10 ^{+ 12} Ω / □ or less, more preferably 5.0 × 10 ^{+ 11} Ω / □ or less, and more preferably 1.0 × 10 ^{+ 11} It is particularly preferable to be Ω / □ or less. When the surface resistivity is large, the ability to escape static electricity generated when the pressure-sensitive adhesive layer is peeled from the adherend is poor. For this reason, by sufficiently reducing the surface resistivity, the peeling voltage generated due to static electricity generated when the pressure-sensitive adhesive layer is peeled from the adherend is reduced, and it is possible to suppress the influence on the adherend.

In the pressure-sensitive adhesive layer obtained by crosslinking the pressure-sensitive adhesive composition of the present embodiment, the peeling voltage of the pressure-sensitive adhesive layer with respect to the low-refractive-index layer formed using the resin composition for forming a low-refractive-index layer containing a fluorine compound is ± 0.3 MPa or less, that is, -0.3 to It is preferably within the range of +0.3 kPa. Examples of the fluorine compound used in the composition for forming the low refractive index layer include fluorinated copolymers, fluorinated copolymers containing fluorinated olefins, fluorinated vinyl ethers, and fluorinated alkyl (meth) acrylates, or fluorinated alkyl groups. And condensation products such as. 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 form an antireflection layer.

When measuring the peeling voltage against the low-refractive-index layer, examples of the substrate for forming the low-refractive-index layer on the surface include a PMMA substrate and a TAC substrate. The pressure-sensitive adhesive layer in which the pressure-sensitive adhesive composition of the present embodiment is crosslinked has a peeling voltage of ± 0.3 kPa or less for the plane layer on which the PMMA substrate and the TAC substrate are not treated, that is, -0.3 to +0.3 kPa. It is preferably within the range of.

After the adhesive layer is adhered to the adherend, it is left for 48 hr under an atmosphere of 60 ° C. at a temperature of 90% RH, and taken out from the atmosphere, the stain resistance after 1 day is “no contamination” on the surface of the adherend. desirable. As an adherend, a polarizing plate in which a protective layer is laminated on a polarizer and the surface of the protective layer is treated with a low-reflection surface with a composition containing a fluorine compound is mentioned. The composition containing the fluorine compound used for the low-reflection surface treatment may be the same or different from the resin composition for forming a low refractive index layer containing the fluorine compound described above. Examples of the protective layer include a PMMA substrate and a TAC substrate.

The adhesive strength of the pressure-sensitive 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 peel rate of 0.3 m / min, and a high speed. It is preferable that the adhesive strength at a peeling speed of 30 m / min is 2.0 N / 25 mm or less, and it is more preferable that the adhesive strength at a high-speed peeling speed of 30 m / min is 0.2 to 1.6 N / 25 mm. For this reason, the performance with little change in adhesive force with the peeling speed is obtained, and it is possible to peel quickly even with high-speed peeling. Moreover, even when peeling off a surface protection film once for re-adhesion, it does not require excessive force, and is easy to peel from an adherend.

The gel fraction of the pressure-sensitive adhesive layer formed by crosslinking the pressure-sensitive adhesive composition of the present embodiment is preferably 95 to 100%, and more preferably 97 to 100%. The high gel fraction of the pressure-sensitive adhesive layer prevents excessive adhesion at low-speed peeling speeds, reduces the dissolution of unpolymerized monomers or oligomers from the copolymer, and improves reworkability and durability at high temperature and high humidity. As a result, contamination of the adherend can be suppressed.

The adhesive film of this embodiment is formed by forming the adhesive layer formed by crosslinking the adhesive composition of this embodiment on one side or both sides of the resin film. Moreover, the surface protection film of this embodiment is a surface protection film formed by forming the adhesive layer formed by crosslinking the adhesive composition of this embodiment on one surface of a resin film. The pressure-sensitive adhesive composition of the present embodiment has excellent antistatic performance, excellent balance of adhesion in low-speed peeling speed and high-speed peeling speed, and also has fouling resistance performance. For this reason, it can use suitably as a use of the surface protection film of a polarizing plate.

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

An antistatic treatment and an antifouling treatment may be performed on the surface opposite to the side on which the pressure-sensitive adhesive layer is formed on one side of the resin film. Examples of the antistatic treatment include coating and mixing of antistatic agents. Examples of the antifouling treatment include treatment with silicone-based, fluorine-based release agents and coating agents, and silica fine particles. The release film may be subjected to a release treatment with a silicone-based, fluorine-based, long-chain alkyl-based release agent or the like on the side of the pressure-sensitive adhesive layer that is aligned with the adhesive surface.

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 side of an optical film. Examples of the optical film include a polarizing film, a retardation film, an antireflection film, an anti-glare (anti-glare) film, an ultraviolet absorbing film, an infrared absorbing film, an optical compensation film, and a brightness enhancing film. Examples of the device to which the optical member is applied include a liquid crystal panel, an organic EL panel, and a touch panel.

In the case of an optical surface protection film and an adhesive film, such as a surface protection film for a polarizing plate, 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 polymers>

[Example 1]

Nitrogen gas was introduced into the reactor equipped with a stirrer, thermometer, reflux cooler, and nitrogen introduction tube, and the air in the reactor was replaced with nitrogen gas. Then, a solvent (ethyl acetate) was added to the reaction apparatus together with 100 parts by weight of 2-ethylhexyl acrylate, 6.0 parts by weight of 8-hydroxyoctyl acrylate, and 0.1 parts by weight of acrylic acid. Thereafter, 0.1 part by weight of azobisisobutyronitrile was added dropwise over 2 hours as a polymerization initiator, and reacted at 65 ° C for 6 hours to obtain an acrylic polymer used in Example 1.

[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 compositions were the same as those described in Tables 1 (A), (B-1), and (B-2), respectively. And acrylic polymer solutions used in Comparative Examples 1 to 3.

<Production of adhesive composition and surface protection film>

[Example 1]

With respect to the acrylic polymer solution of Example 1 prepared as described 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 catalyst (titanium trisacetylacetonate) and 8.5 parts by weight of acetylacetone were added and mixed with stirring to obtain the pressure-sensitive adhesive composition of Example 1. After apply | coating this adhesive composition on a release film (silicone resin-coated PET film), the solvent was removed by drying at 90 degreeC, and the adhesive layer with a thickness of 20 micrometers was obtained. Thereafter, the pressure-sensitive adhesive layer having a release film formed on a surface opposite to the surface of the antistatic and antifouling treatment of the base film (an antistatic and antifouling treated PET film on one side) was transferred to the substrate layer, and the substrate layer / adhesive layer / Release film ”to obtain a surface protective film of Example 1 having a laminated structure.

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

The surface protective films of Examples 2 to 6 and Comparative Examples 1 to 3 were prepared in the same manner as in the surface protective films of Example 1, except that the composition of the additives was as described in Tables (C) to (F) in Table 1, respectively. Got.

In Table 1, the weight part of each component was calculated | required by making the total of (meth) acrylic acid ester monomers of (C) C18 to C18 of an alkyl group into 100 weight part.

Here, in Table 1, in each column of (C) to (F), the acrylic polymer was used as 100 parts by weight, and the content ratio (parts by weight) of each component was shown in numerical values 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.

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

<Test method and evaluation>

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 humidity, respectively, and then evaluated by the following test methods.

<Testing method for adhesive strength>

The release film was peeled off and the surface protection film exposing the pressure-sensitive adhesive layer was pasted onto the surface of the polarizing plate via the pressure-sensitive adhesive layer, left to stand for 1 day, and autoclaved at 50 ° C, 5 atmospheres, and 20 minutes, and additionally 12 at room temperature. What was left for time was used as the measurement sample of adhesive force. The obtained measurement sample was peeled off at a low speed (0.3 m / min) or a high speed (30 m / min) using a tensile tester in the direction of 180 ° to determine the peel strength measured.

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 addition, the LR polarizing plate and the AG-LR polarizing plate have a low-reflective surface treatment with a composition in which the surfaces of the polarizer protective layer of the polarizing plate contain a fluorine compound.

<Test method for surface resistivity>

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

<Test method of peeling high voltage>

The release film was peeled off and the surface protective film exposing the pressure-sensitive adhesive layer was adhered to a polarizing plate having a low refractive index layer formed using a composition for forming a low refractive index layer containing a fluorine compound on the adherend. When the surface protection film was peeled 180 ° at a tensile speed of 30 m / min, the voltage (high voltage) generated by charging of the adherend was measured using high-accuracy electrostatic sensors SK-035 and SK-200 (manufactured by Keyence Co., Ltd.). , The maximum value of the measured value was taken as the peeling large voltage.

<Test method for pollution resistance>

A polarizing plate subjected to low-reflection (LR) surface treatment on one side of the glass plate was pasted through an adhesive layer (double-sided adhesive tape) using a bonding machine. Then, the surface protection film was stuck on the surface of the said polarizing plate using the bonding machine. After bonding to the adherend, the mixture was left for 48 hr under an atmosphere of 60 ° C. at a temperature of 90% RH, taken out from the atmosphere, and after 1 day, the surface protective film was peeled off, and the contamination state of the polarizing plate surface was visually observed. As a criterion for determining the stain resistance, the surface of the polarizing plate was evaluated as "○" for no contamination, "△" for some contamination, and "X" for contamination.

Table 3 shows the evaluation results for the surface protective films in Examples 1 to 6 and Comparative Examples 1 to 3. "Surface resistivity" is expressed by a method in which "m x 10 ^{+ n} " is "mE + n" (where m is an arbitrary real value and n is a positive integer).

The column of "peelable high voltage" indicates 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. The same was applied to the column of "antifouling performance", and the material (PMMA) and surface treatment (AG-LR) of the polarizer protective layer of the polarizing plate used in the test were shown.

The surface protective films of Examples 1 to 6 had an adhesive strength at a low-speed peeling rate of 0.3 m / min to a polarizing plate as an adherend of 0.04 to 0.2 N / 25 mm, and an adhesive strength at a high-speed peeling speed of 30 m / min of 2.0 N / 25 mm. It was as follows and was excellent in adhesive performance.

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

In addition, the surface protection films of Examples 1 to 6 also had an untreated PMMA base material and a TAC base material that did not have a low refractive index layer, and the peeling voltage of the pressure-sensitive adhesive layer was within the range of -0.3 to +0.3 kPa, antistatic performance. This was excellent.

Further, the surface protective films of Examples 1 to 6 were adhered to the adherend, left for 48 hr under an atmosphere of 60 ° C. at a temperature of 90% RH, and taken out from the atmosphere, and after 1 day, the polarizing plate was subjected to low-reflection surface treatment as an adherend. There was no contamination on the soil, and the fouling resistance was excellent.

That is, it was proved that the problems of the present invention can be solved from the evaluation results shown in Table 3 for the surface protective films of Examples 1 to 6.

In the surface protection film of Comparative Example 1, an antistatic agent having a melting point of more than 80 ° C was contained. For this reason, the surface protection film of Comparative Example 1 had a large adhesive strength of the pressure-sensitive adhesive layer, high peeling voltage, and poor stain resistance.

In addition, the surface protection film of Comparative Example 2 contained an antistatic agent having a melting point of more than 80 ° C. For this reason, the surface protection film of Comparative Example 2 had a large adhesive strength of the pressure-sensitive adhesive layer, high peeling voltage, and poor stain resistance.

In addition, the surface protection film of Comparative Example 3 has a melting point of 25 to 80 ° C, but anion contains an antistatic agent having an imide group. For this reason, the surface protection film of Comparative Example 3 had a high peeling voltage with respect to the PMMA substrate, and the fouling performance was also poor.

Thus, the problems of the present invention could not be solved in the surface protective films of Comparative Examples 1 to 3.

Claims (10)

As an adhesive composition containing an acrylic polymer, (F) antistatic agent, and (C) crosslinking agent,
The antistatic agent (F) is an ionic compound having a melting point of 25 to 80 ° C represented by the following formula (1),
K ⁺ · A ^- (1)
[In the formula (1), K ⁺ is pyridinium, imidazolium, phosphonium, sulfonium, pyrrolidinium, guanidinium, ammonium, isouronium, thiuronium, piperidinium, pyrazolium, methylium , Is a type of cation selected from the group consisting of morpholinium, and A ^- is a type of anion selected from the group consisting of trifluoromethanesulfonate anion that does not contain an imide group, and pentafluoroethanesulfonate anion. ]
The acrylic polymer is an acrylic polymer having a glass transition point temperature of 0 ° C or less,
An adhesive composition comprising 100 parts by weight of the acrylic polymer containing the ionic compound as an essential component in a proportion of 0.01 to 10 parts by weight. According to claim 1,
The acrylic polymer
(A) The total amount of at least one or more of the (B-1) copolymerizable vinyl monomer containing a hydroxyl group is 0.01 to 100 parts by weight of at least one or more of the (meth) acrylic acid ester monomers having C1 to C18 carbon atoms in the alkyl group. 10 parts by weight, and / or (B-2) an acrylic polymer of a copolymer obtained by copolymerizing at least one or more total of copolymerizable vinyl monomers containing a carboxyl group at a ratio of 0.01 to 0.5 parts by weight,
Of (A) 100 parts by weight of at least one or more total of (meth) acrylic acid ester monomers having 1 to 18 carbon atoms in the alkyl group, isooctyl (meth) acrylate, isononyl (meth) acrylate, 2-ethylhexyl (meth) ) Is made by containing at least one selected from the group consisting of acrylates in a proportion of 50 parts by weight or more,
With respect to 100 parts by weight of the acrylic polymer, the (C) is a crosslinking agent containing a trifunctional or higher isocyanate compound in a proportion of 0.1 to 10 parts by weight,
The pressure-sensitive adhesive composition further comprises (D) a crosslinking accelerator of the metal chelate compound and (E) a ketoenol tautomer compound. According to claim 2,
The surface resistivity of the pressure-sensitive adhesive layer crosslinked with the pressure-sensitive adhesive composition is 1.0 × 10 ^{+ 12} Ω / □ or less,
Peeling high voltage for the low refractive index layer formed using the resin composition for forming a low refractive index layer containing a fluorine compound on the surfaces of the PMMA substrate and the TAC substrate of the pressure-sensitive adhesive layer, and no treatment on the surfaces of the PMMA substrate and the TAC substrate All peeling voltages for the unplanned plain layer are ± 0.3 kV or less,
After the pressure-sensitive adhesive layer is laminated with a protective layer on a polarizer, the surface of the protective layer is adhered to an adherend which is a polarizing plate treated with a low-reflection surface with a composition containing a fluorine compound, and then left for 48 hrs under an atmosphere of 60 ° C. and 90% RH humidity. And the contamination resistance after 1 day after taking out from the atmosphere is "no contamination" with respect to the surface of the adherend,
The adhesive strength of the pressure-sensitive adhesive layer 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 at a high-speed peeling speed of 30 m / min. The adhesive composition is characterized in that the adhesive force of 2.0N / 25㎜ or less. The method of claim 2 or 3,
The (B-1) 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 of compounds consisting of hydroxyethyl (meth) acrylate, N-hydroxy (meth) acrylamide, N-hydroxymethyl (meth) acrylamide, and N-hydroxyethyl (meth) acrylamide ego,
The (B-2) copolymerizable vinyl monomer containing a carboxyl group is (meth) acrylic acid, carboxyethyl (meth) acrylate, carboxypentyl (meth) acrylate, 2- (meth) acryloyloxyethyl hexahydrophthalic acid, 2- (meth) acryloyloxypropylhexahydrophthalic acid, 2- (meth) acryloyloxyethylphthalic acid, 2- (meth) acryloyloxyethylsuccinic acid, 2- (meth) acryloyloxyethylmaleic acid , At least one selected from the group consisting of carboxypolycaprolactone mono (meth) acrylate and 2- (meth) acryloyloxyethyltetrahydrophthalic acid. The method of claim 2 or 3,
The pressure-sensitive adhesive composition in a proportion of 0.001 to 0.5 parts by weight of the cross-linking accelerator of the (D) metal chelate compound, and 0.1 to 300 parts by weight of the (E) ketoenol tautomer compound relative to 100 parts by weight of the acrylic polymer. Is made of,
The crosslinking accelerator of the metal chelate compound (D) is at least one selected from the group consisting of aluminum chelate compounds, titanium chelate compounds, and iron chelate compounds,
The pressure-sensitive adhesive composition, characterized in that the weight part ratio of (E) / (D) is 70 to 1000. An adhesive film comprising a pressure-sensitive adhesive layer obtained by crosslinking the pressure-sensitive adhesive composition of any one of claims 1 to 3 on one side of a resin film. Surface protective film using the adhesive film of claim 6. Surface protective film for polarizing plates using the adhesive film of claim 6. An optical film in which an adhesive layer in which an adhesive layer obtained by crosslinking the adhesive composition of any one of claims 1 to 3 is laminated on at least one side of an optical film. The method of claim 6,
An adhesive film which has an antistatic treatment and an antifouling treatment on one side of the resin film opposite to the side on which the adhesive layer is formed.