KR102402762B1 - Adhesive composition and surface-protective film - Google Patents

Abstract

The present invention has excellent balance of adhesive force at low and high peel rates, has excellent stain resistance and excellent adhesive performance, and can be used for surface substrates made of TAC, PMMA, and PET, and has excellent antistatic performance without deterioration over time To provide a pressure-sensitive adhesive composition and a surface protection film capable of forming a pressure-sensitive adhesive layer having the same pressure-sensitive adhesive composition. Polyalkylene glycol chain-containing mono (meth) acrylic acid ester monomer is copolymerized without the first acrylic polymer of a copolymer having an acid value of 0.1 to 1.0, and polyalkylene glycol chain-containing mono (meth) acrylic acid ester monomer copolymerized A second acrylic polymer of the copolymer, (D) a trifunctional or more isocyanate compound, (G) an ionic compound having a melting point of 25 to 50° C. having an anion having a fluorine atom number of F7 or more, (E) a crosslinking retarder, ( F) A crosslinking catalyst other than a tin compound is contained as a crosslinking catalyst.

Description

An adhesive composition and a surface protection film {ADHESIVE COMPOSITION AND SURFACE-PROTECTIVE FILM}

The present invention relates to a pressure-sensitive adhesive composition containing an antistatic agent and a surface protection film. More specifically, by adhering to a polarizing plate constituting a liquid crystal display to form an adhesive layer of a surface protection film used for the purpose of protecting the surface of a polarizing plate, an adhesive composition containing an antistatic agent, and a surface protection film using the same will be. The pressure-sensitive adhesive composition of the present invention has excellent adhesion performance and excellent antistatic performance without deterioration over time.

Conventionally, in the process of manufacturing optical members, such as a polarizing plate which is a member which comprises a liquid crystal display, a surface protection film is affixed for temporary protection of the optical member surface. Such a surface protection film is used only in the process of manufacturing an optical member, and peels and removes from an optical member at the time of incorporating an optical member into a liquid crystal display. Since the surface protection film for protecting the surface of such an optical member is used only in a manufacturing process, it is also generally called a process film.

Thus, the surface protection film used in the process of manufacturing an optical member has the structure in which the adhesive layer was formed in the single side|surface of the polyethylene terephthalate (PET) resin film which has optical transparency. On the adhesive layer of a surface protection film, in order to protect the adhesive layer, the release film to which the mold release process was given is pasted together until it bonds to an optical member.

Moreover, optical members, such as a polarizing plate, are subjected to a product inspection accompanied by optical evaluation of the display ability of a liquid crystal display panel, color, contrast, foreign matter mixing, etc. in the state which the surface protection film was pasted together.

For this reason, as a performance requested|required with respect to a surface protection film, that bubble, a foreign material, and the low molecular-weight component of an adhesive composition do not adhere to an adhesive layer, ie, having stain resistance is calculated|required.

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

In addition, in recent years, as a polarizer protective layer (also referred to as a protective film) of a polarizing plate, in addition to conventional triacetyl cellulose (TAC), acrylic resins such as polymethyl methacrylate (PMMA), polyethylene terephthalate (PET), poly Adoption of materials, such as an ester resin, a cyclic olefin type polymer, and polycarbonate, is expanding. Since the protective layer made of these materials tends to generate peeling charging when peeling the surface protection film bonded to the polarizing plate, the pressure-sensitive adhesive layer for the surface protection film of the polarizing plate is required to have superior antistatic performance compared to the prior art.

Moreover, when finally peeling a surface protection film from optical members, such as a polarizing plate, what can peel quickly is required. In order to be able to peel quickly even by what is called a high-speed peeling, it is calculated|required that there are few changes in adhesive force with peeling speed.

As such, in recent years, in terms of ease of use when using a surface protection film, as a performance required for the pressure-sensitive adhesive layer constituting the surface protection film, (1) a balance of adhesive strength in a low-speed peeling rate and a high-speed peeling rate Thing, (2) having stain resistance, (3) excellent antistatic performance, and the like are required.

However, with respect to these (1) to (3), which are the performance requirements for the pressure-sensitive adhesive layer constituting the surface protection film, (1) to (3) required for the pressure-sensitive adhesive layer of the surface protection film even if the individual performance requirements can be satisfied, respectively. ), it was a difficult task to satisfy all the required performance simultaneously. In addition, materials such as acrylic resins such as polymethyl methacrylate (PMMA) other than TAC, which are conventionally used protective layer materials, polyester resins such as polyethylene terephthalate (PET), cyclic olefin polymers, polycarbonates, etc. It was also a very difficult subject to form with the same adhesive composition the adhesive layer of the surface protection film which can be used with respect to the employ|adopted protective layer surface and which satisfy|fills the required performance of these (1)-(3).

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

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

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

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

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

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

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

Moreover, (3) About the outstanding antistatic performance, the method etc. which make a base film contain an antistatic agent are known as a method for providing antistatic property to a surface protection film.

Examples of the antistatic agent include (a) quaternary ammonium salts, pyridinium salts, and various cationic antistatic agents having cationic groups such as primary to tertiary amino groups, (b) sulfonate groups, sulfate groups, and phosphate esters. Anionic antistatic agents having anionic groups such as bases and phosphonate groups, (c) amphoteric antistatic agents such as amino acids and aminosulfate esters, (d) nonionics such as aminoalcohols, glycerols, and polyethylene glycols Antistatic agent, (e) A high molecular weight antistatic agent as described above is disclosed (Patent Document 4).

Moreover, in recent years, making a base film contain such an antistatic agent, or making it contain in an adhesive layer without apply|coating to the surface of a base film is proposed.

Further, an antistatic pressure-sensitive adhesive composition in which a salt having an anion having a fluoro group and a sulfonyl group is dispersed, wherein the salt having an anion having a fluoro group and a sulfonyl group is a polyether ester comprising a polyether group in the main chain. An antistatic pressure-sensitive adhesive composition, which is dispersed in a dissolved state in a plasticizer, is disclosed (Patent Document 5).

In the pressure-sensitive adhesive composition described in Patent Document 5, as a plasticizer, an ester formed of a mono or dicarboxylic acid having a saturated or unsaturated acyclic hydrocarbon group and an alcohol having an acyclic hydrocarbon group having 1 to 20 carbon atoms, or the unsaturated acyclic hydrocarbon group. The use of a plasticizer composed of an ester in which the unsaturated group in the hydrocarbon group is epoxidized is disclosed. The mono- or dicarboxylic acid having such a saturated or unsaturated acyclic hydrocarbon group has a carbon number close to the carbon number of the acrylic monomer constituting the acrylic copolymer used in the pressure-sensitive adhesive layer, thereby improving compatibility with the antistatic pressure-sensitive adhesive composition, Bleed-out is suppressed because it is preferably retained in the plasticizer acrylic antistatic pressure-sensitive adhesive composition.

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

As described above, in the prior art, as the required performance for the pressure-sensitive adhesive layer constituting the surface protection film, having a balance of adhesive force in a low-speed peeling rate and a high-speed peeling rate, having stain resistance, and having excellent antistatic performance things have been requested. However, although each required performance could be satisfied, it was not able to satisfy all the required performance requested|required of the adhesive layer of a surface protection film at the same time.

In addition, in the prior art, it was not possible to prepare an adhesive layer that can be used for all of the surface substrates made of TAC, PMMA, and PET, and that simultaneously satisfy all of the performance requirements required for the pressure-sensitive adhesive layer of the surface protection film.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a pressure-sensitive adhesive composition and a surface protection film excellent in the balance of adhesive force in a low-speed peeling rate and a high-speed peeling rate, and having stain resistance and excellent adhesion performance. . In addition, it is a task to provide a pressure-sensitive adhesive composition and a surface protection film that can be used on a surface substrate made of TAC, PMMA, and PET, and that can form a pressure-sensitive adhesive layer having excellent antistatic performance without deterioration over time with the same pressure-sensitive adhesive composition do.

In a pressure-sensitive adhesive composition having antistatic performance and a surface protection film using the same, the relationship between antistatic performance and stain resistance to an adherend is a trade-off relationship, and improving stain resistance while maintaining antistatic performance is It was very difficult.

Accordingly, the inventors of the present invention do not contain a polyalkylene glycol chain-containing mono (meth) acrylic acid ester monomer with respect to the pressure-sensitive adhesive composition, but a first acrylic polymer copolymerized with a copolymerizable monomer containing a carboxyl group, and polyalkylene glycol A second acrylic polymer containing a chain-containing mono(meth)acrylic acid ester monomer, preferably a polyether-containing silicone compound, and an anion having F7 or more fluorine atoms (for example, a nonafluorobutanesulfonate anion) having a melting point of 25 This subject was solvable by making it the technical idea of this invention that it is an adhesive composition containing the antistatic agent which consists of an ionic compound more than degreeC.

In order to solve the above problems, the present invention is a pressure-sensitive adhesive composition containing an acrylic polymer, an antistatic agent, and a crosslinking agent, wherein the acrylic polymer is the following first acrylic polymer and a second acrylic polymer,

The first acrylic polymer,

(A) with respect to a total of 100 parts by weight of at least one or more kinds of (meth)acrylic acid ester monomers having C1-C18 carbon atoms in the alkyl group,

(B) a total of 1.0 to 6.0 parts by weight of at least one or more copolymerizable monomers containing a hydroxyl group;

(C) 0.01 to 0.6 parts by weight in total of at least one or more copolymerizable monomers containing a carboxyl group

A polyalkylene glycol chain-containing mono (meth) acrylic acid ester copolymer copolymerized without a monomer having an acid value of 0.1 to 1.0 and a weight average molecular weight of more than 300,000 and not more than 1.2 million is the first acrylic polymer of the copolymer,

The first acrylic polymer contains (A) 2-ethylhexyl acrylate in a ratio of 70 parts by weight or more in a total of 100 parts by weight of at least one or more types of (meth)acrylic acid ester monomers having C1-C18 carbon atoms in the alkyl group. done,

The second acrylic polymer,

(a) at least one or more kinds of (meth)acrylic acid ester monomers having C1-C18 carbon atoms in the alkyl group;

(b) at least one or more copolymerizable monomers containing a hydroxyl group;

(c) at least one or more of the polyalkylene glycol chain-containing mono (meth) acrylic acid ester monomer

It is a second acrylic polymer of the copolymerized copolymer,

The glass transition temperature of the first acrylic polymer and the second acrylic polymer is 0° C. or less,

The crosslinking agent is (D) a trifunctional or more isocyanate compound,

The antistatic agent is (G) an ionic compound having a melting point of 25 to 50° C. comprising a cation and an anion having an anion in which the number of fluorine atoms is F7 or more,

The pressure-sensitive adhesive composition further comprises (E) a crosslinking retarder and (F) a crosslinking catalyst other than a tin compound as a crosslinking catalyst.

The pressure-sensitive adhesive composition of the present invention is a pressure-sensitive adhesive composition for a surface protection film bonded to a polarizer protective layer of a polarizing plate, wherein the polarizer protective layer of the polarizing plate is one selected from the group consisting of a TAC-based film, a PMMA-based film, and a PET-based film, and It is preferable that the surface treatment applied to the surface of the polarizer protective layer of the polarizing plate is one selected from the group consisting of untreated, AG treatment, LR treatment, AR treatment, AG-LR treatment, and AG-AR treatment.

The anion of the ionic compound is C ₆ F ₅ (CF ₂ ) _n COO ⁻ , C ₆ F ₅ (CF ₂ ) _n SO ₃ ⁻ , C ₆ F ₅ (CF ₂ ) _n O ⁻ , C ₆ F ₅ O ( CF ₂ ) _n SO ₃ ^- , (C ₆ F ₅ CO) ₂ N ^- , (C ₆ F ₅ CO) ₃ C ^- , (C ₆ F ₅ SO ₂ ) ₂ N ^- , (C ₆ F ₅ SO ₂ ) Consists of ₃ C ^- , (C ₆ F ₅ OSO ₂ ) ₂ N ^- , (C ₆ F ₅ OSO ₂ ) ₃ C ^- , (C ₆ F ₅ ) ₄ B ^- , CF ₃ (CF ₂ ) ₃ SO ₃ ^- It is preferable to contain at least one or more selected from the group as an anion, and to contain the ionic compound in a ratio of 0.01 to 15 parts by weight based on 100 parts by weight of the first acrylic polymer.

The cation of the ionic compound is pyridinium, imidazolium, phosphonium, sulfonium, pyrrolidinium, guanidinium, ammonium, isouronium, thiouronium, piperidinium, pyrazolium, methylium, lithium, It is one type selected from the group consisting of morpholium, and it is preferable to contain the said ionic compound in the ratio of 0.01-15 weight part with respect to 100 weight part of the said 1st acrylic polymer.

The surface resistivity of the pressure-sensitive adhesive layer crosslinked with the pressure-sensitive adhesive composition is 1.0×10 ⁺¹² Ω/□ or less, and the low-refractive-index layer formed by using a composition for forming a low-refractive-index layer containing a fluorine compound on the adherend surface Peeling of the pressure-sensitive adhesive layer The charging voltage is in the range of -0.3 to +0.3 kV, and the adhesive force of the pressure-sensitive adhesive layer formed by crosslinking the pressure-sensitive adhesive composition to a polarizing plate at a low peel rate of 0.3 m/min is 0.04 to 0.2 N/25 mm, and a high peel rate It is preferable that the adhesive force in 30 m/min is 2.0 N/25 mm or less.

The copolymerizable monomer containing the hydroxyl group (B) of the first acrylic polymer and the copolymerizable monomer containing the hydroxyl group (b) of the second acrylic polymer are 8-hydroxyoctyl (meth)acrylate, 6-hydroxy hydroxyhexyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, 2-hydroxyethyl (meth) acrylate, N-hydroxy (meth) acrylamide, N-hydroxymethyl (meth) acrylamide , N-hydroxyethyl (meth) at least one selected from the group consisting of acrylamide, the copolymerizable monomer containing the (C) carboxyl group is (meth) acrylic acid, carboxyethyl (meth) acrylate, carboxypentyl (meth)acrylate, 2-(meth)acryloyloxyethylhexahydrophthalic acid, 2-(meth)acryloyloxypropylhexahydrophthalic acid, 2-(meth)acryloyloxyethylphthalic acid, 2-(meth) ) from the group of compounds consisting of acryloyloxyethyl succinic acid, 2-(meth)acryloyloxyethylmaleic acid, carboxypolycaprolactone mono(meth)acrylate, and 2-(meth)acryloyloxyethyltetrahydrophthalic acid. It is preferable that at least one selected type is selected.

The (E) crosslinking retardant is a ketoenol tautomer compound, and the (E) crosslinking retarder is contained in an amount of 0.1 to 300 parts by weight based on 100 parts by weight of the first acrylic polymer, and (F) The crosslinking catalyst is at least one metal chelate compound selected from the group consisting of an aluminum chelate compound, a titanium chelate compound, and an iron chelate compound, and 0.001 to 0.5 weight of the (F) crosslinking catalyst based on 100 parts by weight of the first acrylic polymer It is comprised in the ratio of parts, and it is preferable that the weight part ratio of said (E)/said (F) is 80-1000.

It is preferable that the said adhesive composition contains the polyether-modified siloxane compound whose HLB value is 6-12 and the weight average molecular weight 10000 or less with respect to 100 weight part of said 1st acrylic polymer in the ratio of 0.01-0.5 weight part.

The pressure-sensitive adhesive composition is made by containing the second acrylic polymer in a ratio of 0.1 to 5.0 parts by weight based on 100 parts by weight of the first acrylic polymer, and as the second acrylic polymer (a) the number of carbon atoms in the alkyl group is C1 to C18 (b) a total of 2.0 to 12.0 parts by weight of at least one copolymerizable monomer containing a hydroxyl group, and (c) a polyalkylene glycol chain-containing mono It is preferable to use the copolymer which copolymerized 1-30 weight part of at least 1 type or more in total of the (meth)acrylic acid ester monomer. And as a weight average molecular weight of the said copolymer, more than 300,000 and 1 million or less are preferable, and especially more than 300,000 and 800,000 or less are preferable.

In addition, at least one copolymerizable monomer containing (B) a hydroxyl group with respect to a total of 100 parts by weight of at least one or more of (meth)acrylic acid ester monomers having C1-C18 carbon atoms in the (A) alkyl group of the first acrylic polymer. The above total parts by weight (β1 = 100×(B)/(A)) and at least one or more of (meth)acrylic acid ester monomers having C1-C18 carbon atoms in the (a) alkyl group of the second acrylic polymer 100 weight The ratio (K = β2/β1) of at least one total weight part (β2 = 100×(b)/(a)) of at least one type of copolymerizable monomer containing a hydroxyl group to the part (K = β2/β1) is in the range of 1.0 to 2.0 it is preferable

The second acrylic polymer is a copolymer having a weight average molecular weight of greater than 300,000 and not more than 800,000, and the polyalkylene glycol chain-containing mono (meth) acrylic acid ester monomer has an average repeating number of alkylene oxide constituting the polyalkylene glycol chain. 3 to 14, the diester content in the polyalkylene glycol chain-containing mono(meth)acrylic acid ester monomer is 0.2% or less, and as the polyalkylene glycol chain-containing mono(meth)acrylic acid ester monomer, polyalkylene glycol mono(meth) ) 1 to 50 parts by weight of at least one selected from the group consisting of acrylate, methoxy polyalkylene glycol (meth) acrylate, and ethoxy polyalkylene glycol (meth) acrylate in 100 parts by weight of the second acrylic polymer It is preferable to contain in the ratio of weight part, 1-40 weight part is more preferable, 1-30 weight part is especially preferable.

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

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

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

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

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

ADVANTAGE OF THE INVENTION According to this invention, it is excellent in the balance of adhesive force in a low-speed peeling rate and a high-speed peeling rate, and can provide the adhesive composition and surface protection film which have stain resistance and excellent adhesive performance. In addition, it is possible to provide a pressure-sensitive adhesive composition and a surface protection film that can be used for a surface substrate made of TAC, PMMA, and PET, and can form a pressure-sensitive adhesive layer having excellent antistatic performance without deterioration with time using the same pressure-sensitive adhesive composition.

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

The pressure-sensitive adhesive composition of this embodiment is a pressure-sensitive adhesive composition containing an acrylic polymer, an antistatic agent, and a crosslinking agent, wherein the acrylic polymer is the following first acrylic polymer and a second acrylic polymer,

The first acrylic polymer,

(A) with respect to a total of 100 parts by weight of at least one or more kinds of (meth)acrylic acid ester monomers having C1-C18 carbon atoms in the alkyl group,

(B) a total of 1.0 to 6.0 parts by weight of at least one or more copolymerizable monomers containing a hydroxyl group;

(C) 0.01 to 0.6 parts by weight in total of at least one or more copolymerizable monomers containing a carboxyl group

A polyalkylene glycol chain-containing mono (meth) acrylic acid ester copolymer copolymerized without a monomer having an acid value of 0.1 to 1.0 and a weight average molecular weight of more than 300,000 and not more than 1.2 million is the first acrylic polymer of the copolymer,

The first acrylic polymer contains (A) 2-ethylhexyl acrylate in a ratio of 70 parts by weight or more in a total of 100 parts by weight of at least one or more types of (meth)acrylic acid ester monomers having C1-C18 carbon atoms in the alkyl group. done,

The second acrylic polymer,

(a) at least one or more kinds of (meth)acrylic acid ester monomers having C1-C18 carbon atoms in the alkyl group;

(b) at least one or more copolymerizable monomers containing a hydroxyl group;

(c) at least one or more of the polyalkylene glycol chain-containing mono (meth) acrylic acid ester monomer

It is a second acrylic polymer of the copolymerized copolymer,

The glass transition temperature of the first acrylic polymer and the second acrylic polymer is 0° C. or less,

The crosslinking agent is (D) a trifunctional or more isocyanate compound,

The antistatic agent is (G) an ionic compound having a melting point of 25 to 50° C. comprising a cation and an anion having an anion in which the number of fluorine atoms is F7 or more,

The pressure-sensitive adhesive composition further comprises (E) a crosslinking retarder and (F) a crosslinking catalyst other than a tin compound as a crosslinking catalyst.

Compared with the conventional pressure-sensitive adhesive composition for a surface protection film, the pressure-sensitive adhesive composition according to the present embodiment has excellent adhesion performance and excellent peeling antistatic performance without deterioration over time.

In particular, the surface protection film according to the present embodiment uses a composition for forming an antifouling layer containing a fluorine compound or a low refractive index layer containing a fluorine compound on the surface of an optical film or the like on which an adherend, such as an optical film, becomes an adherend. In the case of a laminated low-refractive-index layer formed by doing this, it has excellent adhesion performance and excellent peeling antistatic performance without deterioration over time compared to conventional surface protection films, and it is remarkable that antistatic performance and stain resistance can be compatible with each other. to indicate the effect.

That is, the pressure-sensitive adhesive composition according to the present embodiment and a surface protection film using the same have excellent adhesion performance and excellent antistatic performance against peeling without deterioration over time, and thus have great industrial use value.

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

The acrylic polymer used in the pressure-sensitive adhesive composition of the present embodiment contains a first acrylic polymer that does not contain a polyalkylene glycol chain-containing mono (meth) acrylic acid ester monomer and a polyalkylene glycol chain-containing mono (meth) acrylic acid ester monomer. is a second acrylic polymer.

The first acrylic polymer includes (A) a (meth)acrylic acid ester monomer having an alkyl group having C1-C18 carbon atoms, (B) a copolymerizable monomer containing a hydroxyl group, and (C) a copolymerizable monomer containing a carboxyl group, polyalkyl It is a copolymer whose glass transition temperature is 0 degreeC or less which was copolymerized without containing a renglycol chain containing mono(meth)acrylic acid ester monomer. In addition, the second acrylic polymer includes (a) at least one type of (meth)acrylic acid ester monomer having an alkyl group having C1-C18 carbon atoms, (b) at least one type of copolymerizable monomer containing a hydroxyl group, and (c) ) Polyalkylene glycol chain-containing mono (meth) acrylic acid ester copolymer copolymerized with at least one type, the glass transition temperature is a copolymer of 0 ° C. or less.

(A) C1-C18 (meth)acrylic acid ester monomer of the alkyl group of the first acrylic polymer and (a) of the second acrylic polymer, the (meth)acrylic acid ester monomer having C1-C18 of the alkyl group includes methyl ( Meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, butyl (meth) acrylate, isobutyl (meth) acrylate, pentyl (meth) acrylate, hexyl (meth) acrylate, heptyl ( Meth) acrylate, octyl (meth) acrylate, isooctyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, nonyl (meth) acrylate, isononyl (meth) acrylate, decyl (meth) acrylic rate, 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. are mentioned. The alkyl group of the alkyl (meth)acrylate monomer may be linear, branched, or cyclic.

The first acrylic polymer used in the pressure-sensitive adhesive composition of the present embodiment contains (A) 2-ethylhexyl acrylate in a total of 100 parts by weight of at least one or more kinds of (meth)acrylic acid ester monomers having C1-C18 carbon atoms in the alkyl group. It is preferable to contain it in the ratio of weight part or more.

The 1st acrylic polymer used for the adhesive composition of this embodiment contains the copolymerizable monomer containing (B) a hydroxyl group. Further, the second acrylic polymer contains (b) a copolymerizable monomer containing a hydroxyl group. Examples of the copolymerizable monomer containing (B) hydroxyl group of the first acrylic polymer and (b) hydroxyl group-containing copolymerizable monomer of the second acrylic polymer include 8-hydroxyoctyl (meth)acrylate, 6-hydroxyhexyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, 2-hydroxyethyl (meth)acrylate, N-hydroxy (meth)acrylamide, N-hydroxymethyl (meth)acrylamide, N - It is preferable that it is at least 1 type or more selected from the group of compounds which consists of hydroxyethyl (meth)acrylamide, etc.

The first acrylic polymer is (A) with respect to a total of 100 parts by weight of at least one or more types of (meth)acrylic acid ester monomers having C1-C18 alkyl group carbon atoms, (B) at least one type of copolymerizable monomer containing a hydroxyl group, a total of 1.0 It is preferable to contain in the ratio of -6.0 weight part, It is more preferable to contain in the ratio of 1.6-5.8 weight part, It is especially preferable to contain in the ratio of 2.1 to 5.8 weight part.

The second acrylic polymer is (a) with respect to 100 parts by weight in total of at least one type of (meth)acrylic acid ester monomer having a C1-C18 alkyl group (b) a total of at least one type of copolymerizable monomer containing a hydroxyl group 2.0 It is preferable to contain in the ratio of -12.0 weight part, It is more preferable to contain in the ratio of 3.0-11.0 weight part, It is especially preferable to contain in the ratio of 4.0-10.0 weight part.

In the first acrylic polymer, (B) at least one total weight part β1 of the hydroxyl group-containing copolymerizable monomer is (A) At least one type of (meth)acrylic acid ester monomer in which the alkyl group has C1-C18 carbon atoms. It is represented by (beta)1 =100x(B)/(A) with respect to 100 weight part in total. Similarly, in the second acrylic polymer, (b) at least one total weight part β2 of the hydroxyl group-containing copolymerizable monomer is (a) at least one (meth)acrylic acid ester monomer in which the alkyl group has C1-C18 carbon atoms. It is represented by (beta)2=100x(b)/(a) with respect to 100 weight part in total of more than a kind. It is preferable that the weight part β2 of (b) in the second acrylic polymer is not less than the weight part β1 of (B) in the first acrylic polymer, and the ratio (K = β2/β1) is in the range of 1.0 to 2.0 desirable.

The 1st acrylic polymer used for the adhesive composition of this embodiment contains the copolymerizable monomer containing (C) a carboxyl group. (C) copolymerizable monomers containing a carboxyl group include (meth)acrylic acid, carboxyethyl (meth)acrylate, carboxypentyl (meth)acrylate, 2-(meth)acryloyloxyethylhexahydrophthalic acid, 2-( Meth)acryloyloxypropylhexahydrophthalic acid, 2-(meth)acryloyloxyethylphthalic acid, 2-(meth)acryloyloxyethylsuccinic acid, 2-(meth)acryloyloxyethylmaleic acid, carboxypoly It is preferable that it is at least 1 sort(s) or more selected from the compound group which consists of caprolactone mono(meth)acrylate, 2-(meth)acryloyloxyethyl tetrahydrophthalic acid, etc.

The first acrylic polymer is (A) with respect to a total of 100 parts by weight of at least one or more types of (meth)acrylic acid ester monomers having C1-C18 alkyl group carbon atoms (C) At least one type of copolymerizable monomer containing a carboxyl group. It is preferable to contain in the ratio of 0.01-0.6 weight part, It is more preferable to contain in the ratio of 0.01-0.5 weight part, It is especially preferable to contain in the ratio of 0.01-0.4 weight part.

The second acrylic polymer used in the pressure-sensitive adhesive composition of the present embodiment contains (c) a polyalkylene glycol chain-containing mono(meth)acrylic acid ester monomer. For this reason, in the adhesive composition of this embodiment, it is thought that the 2nd acrylic polymer containing this (c) polyalkylene glycol chain containing mono(meth)acrylic acid ester monomer is functioning as an antistatic adjuvant. The second acrylic polymer is preferably contained in a proportion of 0.1 to 5.0 parts by weight, more preferably in a proportion of 0.1 to 3.5 parts by weight, and is contained in a proportion of 0.1 to 2.5 parts by weight, based on 100 parts by weight of the first acrylic polymer. It is particularly preferable to be

When content of a 2nd acrylic polymer is less than the said range, surface resistivity and peeling electrification voltage become high, and antistatic performance falls. Moreover, the stain resistance with respect to a polarizing plate becomes inferior.

(c) The polyalkylene glycol chain-containing mono(meth)acrylic acid ester monomer may be a compound in which one hydroxyl group among a plurality of hydroxyl groups of polyalkylene glycol is esterified as a (meth)acrylic acid ester. Since the (meth)acrylic acid ester group becomes a polymerizable group, it can copolymerize with the 2nd acrylic polymer. Polyalkylene glycol mono(meth)acrylate in which another hydroxyl group is OH as it is may be sufficient, and the alkoxy polyalkylene glycol mono(meth)acrylate etc. in which the other hydroxyl group was converted into alkyl ether may be sufficient. On the other hand, polyalkylene glycol mono(meth)acrylate is not classified as (B) or (b) even if it contains a hydroxyl group at the point corresponding to (c).

The polyalkylene glycol constituting the polyalkylene glycol chain may be a glycol compound having one or more alkylene groups, for example, polyethylene glycol, polypropylene glycol, polybutylene glycol, polyethylene glycol-polypropylene Glycol, polyethylene glycol - polybutylene glycol, polypropylene glycol - polybutylene glycol, polyethylene glycol - polypropylene glycol - polybutylene glycol, etc. are mentioned.

(c) The polyalkylene glycol chain-containing mono(meth)acrylic acid ester monomer preferably has an average repeating number of 3 to 14 alkylene oxides constituting the polyalkylene glycol chain. "Average number of repetitions of alkylene oxide" is the average number of repetitions of alkylene oxide units in the "polyalkylene glycol chain" portion included in the molecular structure of (c) polyalkylene glycol chain-containing mono(meth)acrylic acid ester monomer. is the number of

Moreover, it is preferable that the diester content in (c) polyalkylene glycol chain containing mono(meth)acrylic acid ester monomer is 0.2 % or less. The "diester fraction in the monomer" refers to the content (weight %) of the polyalkylene glycol di(meth)acrylic acid ester contained in the (c) polyalkylene glycol chain-containing mono(meth)acrylic acid ester monomer.

(c) polyalkylene glycol chain-containing mono (meth) acrylic acid ester monomers include polyalkylene glycol mono (meth) acrylate, methoxy polyalkylene glycol (meth) acrylate, ethoxy polyalkylene glycol (meth) At least one selected from the group consisting of acrylates is preferable. The ratio of (c) polyalkylene glycol chain-containing mono(meth)acrylic acid ester monomer in the second acrylic polymer is preferably 1 to 50 parts by weight, and 2 to 35 parts by weight in 100 parts by weight of the second acrylic polymer. A ratio is more preferable, and the ratio of 2-25 weight part is especially preferable.

In addition, (c) polyalkylene glycol chain-containing mono (meth) acrylic acid ester monomer, polyalkylene glycol mono (meth) acrylate, methoxy polyalkylene glycol (meth) acrylate, ethoxy polyalkylene glycol (meth) ) It is preferable to contain at least one selected from the group consisting of acrylates in a ratio of 1 to 50 parts by weight, more preferably 1 to 40 parts by weight, and 1 to 30 parts by weight, based on 100 parts by weight of the second acrylic polymer. Especially preferred.

In addition, (a) with respect to a total of 100 parts by weight of at least one or more of (meth)acrylic acid ester monomers having C1-C18 alkyl group carbon atoms, (c) at least 1 of (c) polyalkylene glycol chain-containing mono(meth)acrylic acid ester monomers It is preferable that the sum total of more than a kind is the ratio of 1-30 weight part.

As monomers other than the (c) polyalkylene glycol chain-containing mono (meth) acrylic acid ester monomer copolymerized with the second acrylic polymer, the (a) alkyl group having C1-C18 carbon atoms (meth) acrylic acid ester monomer and ( b) At least 1 or more types, such as a copolymerizable monomer containing a hydroxyl group, are mentioned. The monomers of (a) and (b) copolymerized with the second acrylic polymer may be different from the monomers of (A) and (B) copolymerized with the first acrylic polymer. The 2nd acrylic polymer does not need to copolymerize the copolymerizable monomer containing a carboxyl group.

The manufacturing method of the acrylic polymer contained in the adhesive composition which concerns on this embodiment is not specifically limited, Well-known polymerization methods, such as a solution polymerization method and an emulsion polymerization method, can be used suitably. As for the weight average molecular weight of the copolymer of a 1st acrylic polymer, more than 300,000 and 1.2 million or less are mentioned, for example. As for the weight average molecular weight of the copolymer of the 2nd acrylic polymer, more than 300,000 and 1 million or less are mentioned, for example, More than 300,000 and 800,000 or less are preferable, and more than 400,000 and 800,000 or less are preferable.

If the weight average molecular weight of the copolymer of the second acrylic polymer is 300,000 or less, the stain resistance to the polarizing plate is poor, which is not preferable.

The acid value of the first acrylic polymer is preferably 0.1 to 1.0. Accordingly, it is possible to improve the stain resistance. Here, "acid value" is one of the index|index showing content of an acid, and it is represented by the mg number of potassium hydroxide required in order to neutralize 1 g of polymer containing a carboxyl group. The acid value of the second acrylic polymer is preferably 1.0 or less, and may be 0.0 when the copolymerizable monomer containing a carboxyl group is not copolymerized with the second acrylic polymer.

The pressure-sensitive adhesive composition according to the present embodiment contains (G) an antistatic agent. The antistatic agent (G) of the present embodiment is an ionic compound comprising a cation and an anion having an anion in which the number of fluorine atoms is F7 or more. The ionic compound has a melting point of 25 to 50°C and is preferably a solid at room temperature (eg, 25°C). It is preferable to contain the said ionic compound in the ratio of 0.01-15 weight part with respect to 100 weight part of 1st acrylic polymer, 0.01-10 weight part is more preferable, 0.01-8 weight part is especially preferable.

As an anion of the ionic compound, C ₆ F ₅ (CF ₂ ) _n COO ⁻ , C ₆ F ₅ (CF ₂ ) _n SO ₃ ⁻ , C ₆ F ₅ (CF ₂ ) _n O ⁻ , C ₆ F ₅ O(CF ₂ ) _n SO ₃ ^- , (C ₆ F ₅ CO) ₂ N ^- , (C ₆ F ₅ CO) ₃ C ^- , (C ₆ F ₅ SO ₂ ) ₂ N ^- , (C ₆ F ₅ SO ₂ ) ₃ C ^- , (C ₆ F ₅ OSO ₂ ) ₂ N ^- , (C ₆ F ₅ OSO ₂ ) ₃ C ^- , (C ₆ F ₅ ) ₄ B ^- , CF ₃ (CF ₂ ) ₃ SO ₃ ^- At least one selected from the group consisting of can be mentioned. Here, n is an integer of 1 or more.

Examples of the cation of the ionic compound include pyridinium, imidazolium, phosphonium, sulfonium, pyrrolidinium, guanidinium, ammonium, isouronium, thiouronium, piperidinium, pyrazolium, methylium, and at least one or more selected from the group consisting of lithium and morpholium.

(G) Specific examples of the antistatic agent include, for example, methyltrioctylammonium tris(pentafluorobenzenesulfonyl)methide salt, 3-methyl-1-octylpyridinium nonafluorobutanesulfonate salt, 1- Ethyl-3-methylimidazolium tetrakispentafluorophenylborate salt, 1-butyl-1-methylpiperidinium bis(pentafluorobenzenesulfonyl)imide salt, etc. are mentioned.

The pressure-sensitive adhesive composition according to the present embodiment further contains (D) a trifunctional or more than trifunctional isocyanate compound as a crosslinking agent. (D) Trifunctional or higher isocyanate compounds include, for example, burette-modified products of diisocyanates such as hexamethylene diisocyanate, isophorone diisocyanate, diphenylmethane diisocyanate, tolylene diisocyanate and xylylene diisocyanate, and isocyanu. The adduct body with trivalence or more polyols, such as a rate modified body, trimethylol propane, and glycerol, etc. are mentioned. (D) As a ratio of the trifunctional or more than trifunctional isocyanate compound, the ratio of 0.01-5 weight part is mentioned with respect to 100 weight part of 1st acrylic polymers, for example.

The pressure-sensitive adhesive composition according to the present embodiment may contain (E) a crosslinking retarder. (E) Crosslinking retarders include β-ketoesters such as methyl acetoacetate, ethyl acetoacetate, octyl acetoacetate, oleyl acetoacetate, lauryl acetoacetate, and stearyl acetoacetate, acetylacetone, and 2,4-hexanedione , and β-diketones such as benzoylacetone. These are ketoenol tautomer compounds, and in the pressure-sensitive adhesive composition using a polyisocyanate compound as a crosslinking agent, by blocking the isocyanate group possessed by the crosslinking agent, excessive increase in viscosity or gelation of the pressure-sensitive adhesive composition after mixing of the crosslinking agent is suppressed, and the pot of the pressure-sensitive adhesive composition life can be extended. (E) The crosslinking retardant is preferably a ketoenol tautomer compound, and particularly preferably at least one selected from the group consisting of acetylacetone and ethyl acetoacetate. It is preferable to contain the (E) crosslinking retarder in the ratio of 0.1-300 weight part with respect to 100 weight part of 1st acrylic polymers.

The adhesive composition which concerns on this embodiment may contain crosslinking catalysts other than a tin compound as (F) a crosslinking catalyst. (F) The crosslinking catalyst should just be a substance which functions as a catalyst with respect to the reaction (crosslinking reaction) of the said copolymer and a crosslinking agent, when using a polyisocyanate compound as a crosslinking agent. As a crosslinking catalyst other than a tin compound, organometallic compounds, such as an amine compound, such as a tertiary amine, a metal chelate compound, an organic lead compound, and an organic zinc compound, etc. are mentioned.

(F) The metal chelate compound of the crosslinking catalyst is a compound in which one or more polydentate ligands L are bonded to a central metal atom M. The metal chelate compound may or may not have one or more monodentate ligands X bonding to the metal atom M. Specific examples of the metal chelate compound include tris(2,4-pentanedionate)iron(III), iron trisacetylacetonate, titanium trisacetylacetonate, ruthenium trisacetylacetonate, zinc bisacetylacetonate, aluminum tris Acetylacetonate, zirconium tetrakisacetylacetonate, tris(2,4-hexanedionate)iron(III), bis(2,4-hexanedionate)zinc, tris(2,4-hexanedionate)titanium, Tris(2,4-hexanedionate)aluminum, tetrakis(2,4-hexanedionate)zirconium, etc. are mentioned.

(F) The crosslinking catalyst is preferably at least one metal chelate compound selected from the group consisting of an aluminum chelate compound, a titanium chelate compound, and an iron chelate compound. It is preferable to contain (F) a crosslinking catalyst in the ratio of 0.001-0.5 weight part with respect to 100 weight part of 1st acrylic polymers.

Since the (E) crosslinking retarder has the effect of suppressing crosslinking as opposed to the (F) crosslinking catalyst, it is preferable to appropriately set the ratio of the (E) crosslinking retarder to the (F) crosslinking catalyst. In order to lengthen the pot life of an adhesive composition and to improve storage stability, it is preferable that the weight part ratio of (E)/(F) is 80-1000. Here, the weight part ratio of (E)/(F) is the value of the quotient obtained by dividing the weight part of (E) by the weight part of (F).

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 more alkyl or aryl groups, R ² and R ³ are one or two or more alkylene groups, R ⁴ is one or more alkyl or acyl groups (terminal groups) indicates. Examples of the polyether group include polyoxyalkylene groups such as polyoxyethylene group [(C ₂ H ₄ O) _n ] and polyoxypropylene group [(C ₃ H ₆ O) _n ]. In the siloxane unit having a polyether group, the terminal of the polyether group may be an OH group (R ⁴ =H in the above general 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 the polyether-modified siloxane compound (H) is contained in a ratio of 0.01 to 0.5 parts by weight, more preferably 0.02 to 0.35 parts by weight, and 0.02 to 0.25 parts by weight with respect to 100 parts by weight of the first acrylic polymer. A ratio is particularly preferred. The HLB value is, for example, the hydrophilic-lipophilic balance (hydrophilic-lipophilic ratio) prescribed in JIS K3211 (Terminology of Surfactant) or the like.

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

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

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

The adhesive composition of this embodiment is suitable as an adhesive composition for surface protection films bonded by the polarizer protective layer of a polarizing plate. Here, the polarizer protective layer of the polarizing plate may be at least one selected from the group consisting of a TAC-based film, a PMMA-based film, and a PET-based film. Here, TAC is triacetyl cellulose, PMMA is polymethyl methacrylate, and PET is an abbreviation of polyethylene terephthalate. You may make it usable with respect to 3 or more types of surface base materials which consist of TAC, PMMA, and PET with the same adhesive layer of the adhesive composition of this embodiment.

In addition, the surface treatment applied to the surface of the polarizer protective layer of the polarizing plate may be at least one selected from the group consisting of untreated, AG treatment, LR treatment, AR treatment, AG-LR treatment, and AG-AR treatment. Here, AG is anti-glare, LR is low reflection, and AR is anti-reflection. In the pressure-sensitive adhesive composition of the present embodiment, the substrate on the surface of the polarizing plate is PMMA or PET, and the stain resistance to at least one or more of the AG-treated, LR-treated, AR-treated, AG-LR-treated, and AG-AR-treated adherends can be improved. can

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

The pressure-sensitive adhesive layer in which the pressure-sensitive adhesive composition of the present embodiment is crosslinked has a peeling electrification voltage of the pressure-sensitive adhesive layer with respect to the low-refractive-index layer formed by using the composition for forming a low-refractive-index layer containing a fluorine compound on the adherend surface is in the range of -0.3 to +0.3 kV. It is preferable to be mine. As a fluorine compound used in the composition for forming a low refractive index layer, a fluorine-containing copolymer that is one or more polymers such as fluorinated olefins, fluorinated vinyl ethers, and fluorinated alkyl (meth) acrylates, fluorinated alkyl group-containing silane compounds, etc. condensates of In addition to the fluorinated monomer, the fluorine-containing copolymer may be copolymerized with non-fluorinated monomers, such as olefins, vinyl ethers, and (meth)acrylate. The low-refractive-index layer may be combined with a high-refractive-index layer or the like to constitute an antireflection layer.

The adhesive force in the low-speed peeling rate 0.3m/min with respect to the polarizing plate of the adhesive layer formed by bridge|crosslinking the adhesive composition of this embodiment is 0.04-0.2N/25 mm, The adhesive force in high-speed peeling speed 30m/min is 2.0N/25 It is preferable that it is mm or less, and it is more preferable that the adhesive force in high-speed peeling speed 30 m/min is 0.2-1.6 N/25 mm. Thereby, the performance with little change in adhesive force also with peeling speed is acquired, and it becomes possible to peel quickly also by high-speed peeling. Further, even when the surface protection film is once peeled for reattachment, it is easy to peel from the adherend without requiring excessive force.

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

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

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

Antistatic treatment and antifouling treatment may be given to the surface opposite to the side in which the said adhesive layer of the resin film single side was formed. The antistatic treatment includes application and inclusion of an antistatic agent. Examples of the antifouling treatment include treatment with silicone-based and fluorine-based mold release agents, coating agents, silica fine particles, and the like. The release film may be subjected to a release treatment with a silicone-based, fluorine-based, or long-chain alkyl-based mold release agent, etc.

Moreover, the optical film with an adhesive layer can be obtained by laminating|stacking the adhesive layer which bridge|crosslinked the adhesive composition of this embodiment on at least one surface of an optical film. 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 luminance enhancing film. As an apparatus to which an optical member is applied, a liquid crystal panel, an organic electroluminescent panel, a touch panel, etc. are mentioned.

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

Example

Hereinafter, the present invention will be specifically described by way of Examples.

<Production of the first acrylic polymer>

[Example 1]

Nitrogen gas was introduced into a reactor equipped with a stirrer, a thermometer, a reflux condenser, and a nitrogen introduction tube to replace air in the reactor with nitrogen gas. Then, the solvent (ethyl acetate) was added to the reaction apparatus with 90 weight part of 2-ethylhexyl acrylates, 10 weight part of methyl acrylates, 5.5 weight part of 8-hydroxyoctyl acrylate, and 0.2 weight part of acrylic acid. Then, 0.1 weight part of azobisisobutyronitrile as a polymerization initiator was dripped over 2 hours, and it was made to react at 65 degreeC for 6 hours, and the 1st acrylic polymer used for Example 1 was obtained.

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

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

<Preparation of adhesive composition and surface protection film>

[Example 1]

2.0 parts by weight of a crosslinking agent (coronate HX), 9 parts by weight of a crosslinking retarder (acetylacetone), 0.1 parts by weight of a crosslinking catalyst (titanium trisacetylacetonate), with respect to the first acrylic polymer solution of Example 1 prepared as described above; 0.9 parts by weight of an antistatic agent (methyltrioctylammonium tris(pentafluorobenzenesulfonyl)methide salt), 0.05 parts by weight of a polyether-modified siloxane compound (HLB=7), 0.2 parts by weight of copolymer B-1 (molecular weight 600,000) The part was added and stirred and mixed, and the adhesive composition of Example 1 was obtained. After apply|coating this adhesive composition on the release film (silicone resin-coated PET film), the solvent was removed by drying at 90 degreeC, and the 20-micrometer-thick adhesive layer was obtained. Thereafter, the adhesive layer with the release film formed on the opposite side to the antistatic and antifouling side of the base film (PET film with antistatic and antifouling treatment on one side) is transferred, and “base film / adhesive layer / release The surface protection film of Example 1 which has the laminated constitution of "film" was obtained.

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

Examples 2 to 6 and Comparative Examples 1 to 3 were carried out in the same manner as in the surface protection film of Example 1, except that the composition of the additive was as described in Table 1 (D) to (H) and copolymer B, respectively. of the surface protection film was obtained.

In Table 1, the weight part of each component was calculated|required as 100 weight part of the sum total of the (A) C1-C18 (meth)acrylic acid ester monomer of the C1-C18 alkyl group. On the other hand, although "I-2" of Comparative Example 2 is described in the column (A) for convenience, (A) it does not correspond to the (meth)acrylic acid ester monomer in which the carbon number of the alkyl group is C1-C18.

On the other hand, in Table 1, in each column of (D), (E), (F), (G), (H), and (copolymer B), the content ratio of each component with 100 parts by weight of the first acrylic polymer ( parts by weight) were expressed as numerical values in parentheses ( ).

In addition, the compound name of the abbreviation of each component used for Table 1 is shown to Tables 2-3. The 2nd acrylic polymer in embodiment mentioned above is "copolymer B", and the meaning of the abbreviation of the component monomers (a), (b), and (c) is (A), (B), (I), respectively. ) is described. On the other hand, Coronate (registered trademark) HX, HL and L are trade names of Toso Corporation, and Takenate (registered trademark) D-140N is a trade name of Mitsui Chemicals Corporation.

(G) Among the antistatic agents, all of G-1 to G-4 have an anion having a number of fluorine atoms of F7 or more, and are solid ionic compounds having a melting point of 25°C or more. G-5 is a solid ionic compound having an anion in which the number of fluorine atoms is F5 and having a melting point of 25°C or higher.

(H) All of H-1 to H-6 among polyether-modified siloxane compounds have a weight average molecular weight of 10000 or less.

(I) Among the polyalkylene glycol chain-containing mono(meth)acrylic acid ester monomers, in I-1 to I-3, the diester content in the monomer is 0.2% or less, and in I-4, the diester content in the monomer is 0.8%. In addition, n in the column of (I) group of Table 3 is a numerical value which shows the average number of repetitions of an alkylene oxide.

<Test method and evaluation>

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

<Test method of adhesion>

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

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

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

<Test method of surface resistivity>

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

<Test method of peeling electrification voltage>

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

<Test method for stain resistance>

On the single side|surface of a glass plate, each polarizing plate chosen from 5 types shown in Table 4 was bonded together through the adhesive layer (double-sided adhesive tape) using the bonding machine. Then, the surface protection film was bonded together on the surface of each polarizing plate using the bonding machine. After storing over the period of 3 days and 30 days in 23 degreeC and 50 %RH environment, the surface protection film was peeled and the contamination state on the surface of a polarizing plate was observed visually. As for the contamination-resistance criterion, the case where there was no contamination on the surface of each polarizing plate was evaluated as "○", the case where there was some contamination as "Δ", and the case where there was contamination was evaluated as "x".

In Table 4, the evaluation result about the surface protection film in Examples 1-6 and Comparative Examples 1-3 is shown. "Surface resistivity" was expressed according to the method (however, m is an arbitrary real value, and n is a positive integer) in which "mx10+ ⁿ " is "mE+n". The "staining resistance (surface substrate/surface treatment)" column shows the evaluation result for each material and surface treatment of 5 types of polarizing plate surface base materials (polarizer protective layer). Plain of "surface treatment" means untreated.

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

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

Further, the surface protection films of Examples 1 to 6 had no contamination on the polarizing plate as an adherend even after storage for 3 days and 30 days, and were excellent in stain resistance.

That is, in the evaluation result shown in Table 4 about the surface protection film of Examples 1-6, it was demonstrated that the subject of this invention could be solvable.

In the adhesive composition of the comparative example 1, the weight average molecular weight of copolymer B-5 is as small as 10,000. Moreover, the diester content of I-4 contained in copolymer B-5 is 0.8 % as much as it is large, and the average number of repetitions n = 23 is large. In addition, the component (b) contained in the copolymer B-5 of the second acrylic polymer is 3 parts by weight, which is less than 5.5 parts by weight of the component (B) contained in the first acrylic polymer. The surface protection film of Comparative Example 1 using this pressure-sensitive adhesive composition had excellent stain resistance against the conventionally used TAC-based polarizing plate, but had slightly poor stain resistance against two types of polarizing plates based on PMMA or PET. .

In addition, in the pressure-sensitive adhesive composition of Comparative Example 2, a polyalkylene glycol chain-containing mono (meth) acrylic acid ester monomer is copolymerized with the first acrylic polymer, and (B) the proportion of the copolymerizable monomer containing a hydroxyl group is as much as 6.5 parts by weight. The surface protection film of Comparative Example 2 using this pressure-sensitive adhesive composition had a low adhesive force of 0.03 N/25 mm at a low peel rate of 0.3 m/min, poor adhesion performance, and poor stain resistance against two types of polarizing plates, , the stain resistance was rather poor with respect to one type of polarizing plate.

Further, in the pressure-sensitive adhesive composition of Comparative Example 3, (C) the proportion of the copolymerizable monomer containing a carboxyl group is 1.5 parts by weight, and the antistatic agent contains an anion whose number of fluorine atoms is F5 less than F7. The surface protection film of Comparative Example 3 using this pressure-sensitive adhesive composition had a high peeling electrification voltage of 0.6 kV, poor antistatic performance, and poor stain resistance to three types of polarizing plates, and stain resistance to one other type of polarizing plate. This was rather poor.

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

On the other hand, in the case of the surface protection film prepared in the same manner as in Example 1 except that copolymer B was not contained, the surface resistivity increased and the peeling electrification voltage was increased, the antistatic performance was poor, and the polarizing plate was The contamination resistance was also poor.

Claims (5)

An adhesive film in which an adhesive layer obtained by crosslinking an acrylic polymer, an antistatic agent, and an adhesive composition containing a crosslinking agent is laminated on one side of a resin film,
The acrylic polymer is the following first acrylic polymer and second acrylic polymer,
The first acrylic polymer,
(A) with respect to a total of 100 parts by weight of at least one or more kinds of (meth)acrylic acid ester monomers having C1-C18 carbon atoms in the alkyl group,
(B) a total of 1.0 to 6.0 parts by weight of at least one or more copolymerizable monomers containing a hydroxyl group;
(C) 0.01 to 0.6 parts by weight in total of at least one or more copolymerizable monomers containing a carboxyl group
A polyalkylene glycol chain-containing mono (meth) acrylic acid ester copolymer copolymerized without a monomer having an acid value of 0.1 to 1.0 and a weight average molecular weight of more than 300,000 and not more than 1.2 million is the first acrylic polymer of the copolymer,
The first acrylic polymer contains (A) 2-ethylhexyl acrylate in a ratio of 70 parts by weight or more in a total of 100 parts by weight of at least one or more types of (meth)acrylic acid ester monomers having C1-C18 carbon atoms in the alkyl group. made,
(B) The copolymerizable monomer containing a hydroxyl group is 8-hydroxyoctyl (meth) acrylate, 6-hydroxyhexyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, 2-hydroxy At least one selected from the group of compounds consisting of ethyl (meth) acrylate, N-hydroxy (meth) acrylamide, N-hydroxymethyl (meth) acrylamide, and N-hydroxyethyl (meth) acrylamide,
The first acrylic polymer is a copolymerizable monomer containing (B) a hydroxyl group, and includes 8-hydroxyoctyl (meth)acrylate, 6-hydroxyhexyl (meth)acrylate, and 4-hydroxybutyl (meth). It comprises at least one selected from the group of compounds consisting of acrylate,
The second acrylic polymer,
(a) at least one or more kinds of (meth)acrylic acid ester monomers having C1-C18 carbon atoms in the alkyl group;
(b) at least one or more copolymerizable monomers containing a hydroxyl group;
(c) at least one or more of the polyalkylene glycol chain-containing mono (meth) acrylic acid ester monomer
It is a copolymerized second acrylic polymer having a weight average molecular weight of more than 300,000 and 1 million or less,
The (c) polyalkylene glycol chain-containing mono (meth) acrylic acid ester monomer contained in the polyalkylene glycol di (meth) acrylic acid ester content is 0.2% by weight or less,
The glass transition temperature of the first acrylic polymer and the second acrylic polymer is 0° C. or less,
The crosslinking agent is (D) a trifunctional or more isocyanate compound,
The antistatic agent is (G) an ionic compound having a fluorine atom number of F7 or more, the ionic compound having a melting point of 25 to 50 ℃ consisting of a cation and an anion,
The adhesive composition further comprises (E) a crosslinking retarder and (F) a crosslinking catalyst other than a tin compound as a crosslinking catalyst, The adhesive film characterized by the above-mentioned. The method of claim 1,
The anion of the ionic compound is C ₆ F ₅ (CF ₂ ) _n COO ⁻ , C ₆ F ₅ (CF ₂ ) _n SO ₃ ⁻ , C ₆ F ₅ (CF ₂ ) _n O ⁻ , C ₆ F ₅ O ( CF ₂ ) _n SO ₃ ^- , (C ₆ F ₅ CO) ₂ N ^- , (C ₆ F ₅ CO) ₃ C ^- , (C ₆ F ₅ SO ₂ ) ₂ N ^- , (C ₆ F ₅ SO ₂ ) Consists of ₃ C ^- , (C ₆ F ₅ OSO ₂ ) ₂ N ^- , (C ₆ F ₅ OSO ₂ ) ₃ C ^- , (C ₆ F ₅ ) ₄ B ^- , CF ₃ (CF ₂ ) ₃ SO ₃ ^- It consists of containing at least one or more selected from the group (here, n is an integer of 1 or more) as an anion,
Adhesive film, characterized in that it contains the ionic compound in a ratio of 0.01 to 15 parts by weight based on 100 parts by weight of the first acrylic polymer. 3. The method of claim 1 or 2,
An adhesive film for a surface protection film bonded to the polarizer protective layer of a polarizing plate, wherein the polarizer protective layer of the polarizing plate is one selected from the group consisting of a triacetyl cellulose-based film, a polymethyl methacrylate-based film, and a polyethylene terephthalate-based film. , In addition, the surface treatment applied to the surface of the polarizer protective layer of the polarizing plate is untreated, anti-glare treatment, low reflection treatment, anti-reflection treatment, anti-glare-low reflection treatment, anti-glare - selected from the group consisting of anti-reflection treatment An adhesive film, characterized in that it is one type. 3. The method of claim 1 or 2,
The resin film is an optical film, and the adhesive film, characterized in that the optical film is formed with an adhesive layer. The adhesive film of Claim 1 or 2 is bonded together as a surface protection film, The polarizing plate characterized by the above-mentioned.