KR20150102005A - Adhesive composition and optical member surface protective film - Google Patents

Abstract

A (meth) acrylic copolymer comprising a first constituent unit represented by the following general formula (1) and a second constituent unit derived from a monomer having a hydroxy group, a polyether-modified silicone having a hydroxyl group at the polyether terminal, Sensitive adhesive composition. In the following general formula (1), R ¹ represents a hydrogen atom or a methyl group. L represents a divalent linking group composed of at least one member selected from the group consisting of an alkylene group, an arylene group, a carbonyl group and an oxygen atom.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to a pressure-sensitive adhesive composition,

The present invention relates to a pressure-sensitive adhesive composition and an optical member surface protective film.

BACKGROUND ART [0002] Liquid crystal display devices have recently been used in a variety of information-related devices because of their small thickness and low power consumption. For example, a liquid crystal display device is used as a screen display device of a word processor or a notebook computer. In such a liquid crystal display panel, optical members such as a polarizing plate and a retardation plate are used together with a glass cell (liquid crystal cell) containing a liquid crystal as a main body.

These optical members are usually coated with a surface protective film so that the surfaces of the optical members are not contaminated or damaged during the steps of punching, inspection, transportation, assembly of liquid crystal panel, etc., . This surface protective film is peeled off from the optical member at the stage where the surface protection is not needed.

Such a surface protective film is required to be adhered to the surface of the optical member so that the surface of the optical member does not deviate or fall off from the surface while the surface of the optical member needs to be protected. In addition, the surface protective film is required to be highly transparent and free from any defects in the pressure-sensitive adhesive layer such as the infiltration, tunneling, and peeling, and the interface between the pressure-sensitive adhesive layer and the optical member so as not to interfere with various tests such as the performance test of liquid crystal . In order to prevent damage to the optical member and the liquid crystal cell due to deformation of the liquid crystal display panel accompanying peeling when the surface protective film is peeled from the optical member and to prevent defects such as peeling of the optical member from the liquid crystal cell, It is required that the film can be easily peeled off. In addition, it is required that the surface protective film does not generate any residue originating from the surface protective film on the optical member at the time of peeling, that is, the stain resistance to an adherend (hereinafter simply referred to as " staining property "

Recently, the peeling speed of the surface protective film tends to be increased for the purpose of improving the working efficiency, and the workability in the high-speed peeling of the surface protective film has also been demanded as the property of the pressure-sensitive adhesive.

On the other hand, when static electricity is generated when the surface protective film is peeled from the optical member, garbage or dust is adsorbed on the surface of the optical film to cause defects in the product. Further, when large static electricity is generated when the surface protective film is peeled off, the circuit of the display member may be destroyed. Therefore, it is required that the antistatic property is good when the surface protective film is peeled off.

In relation to the above, JP-A-2009-275128 discloses a pressure-sensitive adhesive comprising an acrylic copolymer, a metal salt and an organopolysiloxane having a polyoxyalkylene group. It is said that the pressure-sensitive adhesive is less contaminated to an adherend and less static electricity is generated by peeling electrification.

Japanese Unexamined Patent Publication (Kokai) No. 2002-277634 discloses a pressure-sensitive adhesive optical film having a pressure-sensitive adhesive layer containing an acryl-based polymer containing a monomer unit having a specific structure having a carboxyl group crosslinked with a polyfunctional compound. This adhesive optical film is said to have superior reworkability and stress relaxation properties.

Japanese Patent Application Laid-Open No. 2006-0612 discloses a surface protective film having a pressure-sensitive adhesive layer formed by extruding a compound containing silicon such as a polyether-modified polyorganosiloxane to an acrylic pressure-sensitive adhesive. This surface protective film is said to inhibit the generation of static electricity.

However, in the pressure-sensitive adhesives described in JP-A-2009-275128, JP-A-2002-277634 and JP-A-2011-063712, it has been difficult to combine antistatic property and low staining property at a higher level.

An object of the present invention is to provide a pressure-sensitive adhesive composition capable of achieving both high antistatic properties and low stain resistance to an adherend at high levels, and an optical member surface protective film using the same.

The present invention includes the following aspects.

(1) a first (meth) acrylic copolymer comprising a first constituent unit represented by the following general formula (1) and a second constituent unit derived from a monomer having a hydroxy group, and a second Silicone, and an alkali metal salt.

(In the general formula (1), R ¹ represents a hydrogen atom or a methyl group.) L represents a divalent linking group composed of at least one kind selected from the group consisting of an alkylene group, an arylene group, a carbonyl group and an oxygen atom.

<2> L in the general formula (1) is at least one selected from the group consisting of a divalent linking group represented by the following general formula (2a) and a divalent linking group represented by the following general formula (2b) Based pressure-sensitive adhesive composition.

(In the formulas (2a) and (2b), R ²¹ to R ²⁴ each independently represent an alkylene group having 1 to 12 carbon atoms or an arylene group having 6 to 10 carbon atoms, n denotes a number of 0 to 10, m Represents a number from 1 to 10.)

<3> The pressure-sensitive adhesive composition according to <1> or <2>, wherein the content of the first structural unit in the first (meth) acrylic copolymer is 0.5% by mass to 5% by mass.

<4> The pressure-sensitive adhesive composition according to any one of <1> to <3>, wherein the content of the polyether-modified silicone is 0.05 part by mass to 0.50 parts by mass with respect to 100 parts by mass of the (meth) acrylic copolymer.

<5> A polymer composition according to any one of <1> to <4>, further comprising a second (meth) acrylic copolymer having a polyalkyleneoxy group-containing structural unit and having a lower molecular weight than the first (meth) Sensitive adhesive composition described in any one of &lt; 1 &gt;

<6> An optical member surface protective film comprising a polyester base material and a pressure-sensitive adhesive layer provided on the pressure-sensitive adhesive composition according to any one of <1> to <5> to be.

According to the present invention, it is possible to provide a pressure-sensitive adhesive composition capable of achieving both a high antistatic property and a low stain resistance to an adherend, and an optical member surface protective film using the same.

The numerical range indicated by using &quot; ~ &quot; in the present specification indicates a range including the numerical values described before and after &quot; ~ &quot; as the minimum value and the maximum value, respectively. In the present specification, the term &quot; amount of each component in the composition &quot; refers to the total amount of the plurality of substances present in the composition, unless otherwise specified, when a plurality of substances corresponding to each component are present in the composition.

Further, (meth) acrylate means at least one of acrylate and methacrylate, and the phrases such as a (meth) acryl copolymer similar to (meth) acrylate have the same meaning.

&Lt; Pressure sensitive adhesive composition &

The pressure-sensitive adhesive composition of the present invention comprises a first (meth) acrylic copolymer comprising a first constituent unit represented by the following general formula (1) and a second constituent unit derived from a monomer having a hydroxy group, Polyether-modified silicone, and an alkali metal salt. The pressure-sensitive adhesive composition may further contain other components as required.

(In the general formula (1), R ¹ represents a hydrogen atom or a methyl group.) L represents a divalent linking group composed of at least one kind selected from the group consisting of an alkylene group, an arylene group, a carbonyl group and an oxygen atom.

Wherein the pressure-sensitive adhesive composition comprises a first (meth) acrylic copolymer comprising a first constituent unit having a specific structure having a carboxyl group and a second constituent unit derived from a monomer having a hydroxy group, a polyether-modified silicone having a hydroxy group at the polyether terminal, , And contains an alkali metal salt, it has excellent antistatic property and low stain resistance to an adherend, excellent adhesiveness, and excellent reliability. Such a pressure-sensitive adhesive composition can be suitably applied to an optical member surface protective film.

This can be considered, for example, as follows. It is believed that the pressure-sensitive adhesive composition contains polyether-modified silicone and that the alkali metal salt can localize near the surface of the pressure-sensitive adhesive composition due to the interaction between the polyether-modified silicone and the alkali metal salt and that the pressure- do. Further, it is considered that the first (meth) acrylic copolymer interacts with the polyether-modified silicone to effectively lower the surface resistance value of the pressure-sensitive adhesive composition, and the pressure-sensitive adhesive composition exhibits more excellent antistatic properties. It is believed that this is due to the fact that the first (meth) acrylic copolymer has both a first constituent unit and a second constituent unit of a specific structure. In particular, it is considered that such a (meth) acrylic copolymer containing a constituent unit having a carboxyl group derived from (meth) acrylic acid or the like other than the first constituent unit having a specific structure as a constituent unit containing a carboxy group can not sufficiently obtain such an effect. Furthermore, when the polyether-modified silicone has a hydroxyl group at the polyether terminal, it is effectively suppressed that the constituent components of the pressure-sensitive adhesive composition remain on the adherend when the pressure-sensitive adhesive is peeled from the adherend, and the pressure- .

[(Meth) acrylic copolymer]

The pressure-sensitive adhesive composition comprises at least a first (meth) acrylic copolymer (hereinafter also referred to as &quot; resin A &quot;) comprising a first constituent unit represented by the general formula (1) and a second constituent unit derived from a monomer having a hydroxy group It contains one species. The pressure-sensitive adhesive composition may further contain a (meth) acrylic copolymer different from the first (meth) acrylic copolymer as needed.

Here, the (meth) acrylic copolymer is at least 50 mass%, preferably at least 90 mass% of the total monomer components constituting the copolymer (the monomers constituting the copolymer may be simply referred to as copolymer components) (Meth) acrylic monomer.

(First (meth) acrylic copolymer)

The first (meth) acrylic copolymer includes at least one kind of the first structural unit represented by the general formula (1). In the first structural unit represented by the general formula (1), L represents a divalent linking group composed of at least one kind selected from the group consisting of an alkylene group, an arylene group, a carbonyl group and an oxygen atom. The alkylene group in L may be straight chain, branched chain or cyclic. When the alkylene group in L is a straight chain or branched chain, the number of carbon atoms of the alkylene group is preferably 1 to 12, more preferably 2 to 10, and even more preferably 2 to 6.

When the alkylene group in L is cyclic, the alkylene group preferably has 3 to 12 carbon atoms, more preferably 4 to 8 carbon atoms, and even more preferably 5 to 6 carbon atoms. For example, when the cyclic alkylene group is a cyclohexylene group, the bonding position may be any of the first and fourth positions, the first position and the second position, the first position and the third position, and preferably the first position and the second position.

The arylene group in L preferably has 6 to 10 carbon atoms, and more preferably a phenylene group. The bonding position in the arylene group is not particularly limited. For example, when the arylene group is a phenylene group, the bonding position may be any of the first and fourth positions, the first position and the second position, the first position and the third position, and preferably the first position and the second position.

The alkylene group and arylene group in L may have a substituent. Examples of the substituent include an alkyl group having 1 to 12 carbon atoms, a halogen atom, a hydroxyl group, an amino group, a nitro group, and a phenyl group.

The divalent linking group represented by L in the general formula (1) is preferably a divalent linking group represented by the following general formula (2a) or general formula (2b) from the viewpoints of antistatic property and low staining property to an adherend.

(In the formulas (2a) and (2b), R ²¹ to R ²⁴ each independently represent an alkylene group having 1 to 12 carbon atoms or an arylene group having 6 to 10 carbon atoms, n denotes a number of 0 to 10, m Represents a number from 1 to 10.)

The alkylene group for R ²¹ to R ²⁴ may be any of linear, branched and cyclic, preferably straight-chain or branched, and more preferably straight-chain.

The bonding position in the arylene group in R ²¹ to R ²⁴ is not particularly limited. For example, when the arylene group is a phenylene group or a cyclohexylene group, the bonding position may be any of the first and fourth positions, the first and second positions, the first position and the third position, and preferably the first position and the second position.

The alkylene group for R ²¹ and R ²² preferably has 2 to 10 carbon atoms, more preferably 2 to 6 carbon atoms. The alkylene groups in R ²¹ and R ^{22 may be} the same or different.

The arylene group in R ²¹ and R ²² is preferably a phenylene group or a naphthylene group, more preferably a phenylene group.

R ²¹ and R ²² in the general formula (2a) are preferably an alkylene group having 1 to 12 carbon atoms, more preferably an alkylene group having 2 to 6 carbon atoms, from the viewpoints of antistatic property and low staining property to an adherend, And more preferably a straight or branched alkylene group having 2 to 6 carbon atoms.

n represents a number of 0 to 10; In the case where only one kind of the first constituent unit represented by the general formula (1) contained in the first (meth) acrylic copolymer is present, n is an integer, and when two or more kinds of the first constituent units are contained, n is a rational number . n is preferably 0 to 4, more preferably 0 to 2.

R ²³ is preferably an alkylene group having 1 to 12 carbon atoms, more preferably an alkylene group having 2 to 6 carbon atoms, and still more preferably an alkylene group having 2 to 4 carbon atoms.

R ²⁴ is preferably a linear or branched alkylene group having 2 to 6 carbon atoms, a cyclic alkylene group having 4 to 8 carbon atoms or an arylene group having 6 to 10 carbon atoms, and is preferably a linear or branched alkyl group having 2 to 4 carbon atoms More preferably a cyclic alkylene group having 5 to 6 carbon atoms or a phenylene group, more preferably a linear or branched alkylene group having 2 to 4 carbon atoms, a cyclohexylene group or a phenylene group.

m represents a number of 1 to 10; M is an integer when only one kind of the first constitutional unit represented by the general formula (1) contained in the first (meth) acrylic copolymer is present, and m is an rational number which is the average value when the first constitutional unit is comprised of two or more kinds . m is preferably 1 to 4, more preferably 1 to 2.

The content ratio of the first constituent unit in the first (meth) acrylic copolymer is preferably 0.5% by mass or more and 5% by mass or less in the total mass of the first (meth) acrylic copolymer from the viewpoints of antistatic property and low stain resistance to the adherend More preferably 0.5% by mass or more and 2% by mass or less, and still more preferably 0.5% by mass or more and 1% by mass or less.

When the content of the first constituent unit in the first (meth) acrylic copolymer is 0.5% by mass or more based on the total mass of the first (meth) acrylic copolymer, the surface resistance of the pressure-sensitive adhesive composition is lowered, There is a tendency to get. If the content of the first constituent unit in the first (meth) acrylic copolymer is 5% by mass or less based on the total mass of the first (meth) acrylic copolymer, increase in the viscosity over time of the pressure- There is a tendency to obtain port life.

The first constituent unit in the first (meth) acrylic copolymer can be produced, for example, by copolymerizing a monomer represented by the following general formula (1a) together with other monomers constituting the first (meth) acrylic copolymer, Acrylic copolymer.

In formula (1a), R ¹ and L is the same and each of R ¹ and L in the formula (1).

The monomer represented by the general formula (1a) may be produced by a conventional method or may be a monomer selected from commercially available monomers. Of the monomers represented by the general formula (1a), examples of the monomer represented by the general formula (2a) wherein L is a (meth) acrylic acid dimer (preferably an average value of n in the general formula (2a) is about 0.4) Polycaprolactone mono (meth) acrylate (preferably an average value of n in the formula (2a) is about 1.0), and the like. These monomers are commercially available, for example, as &quot; M-5600 &quot;, &quot; M-5300 &quot; (trade name, product of TOA Corporation).

Of the monomers represented by the general formula (1a), examples of the monomer represented by the general formula (2b) wherein L is 2- (meth) acryloyloxyethylsuccinic acid, 2- (meth) acryloyloxyethyl fumaric acid, 2- ) Acryloyloxyethylhexahydrophthalic acid, 2- (meth) acryloyloxyethylphthalic acid, and the like. These monomers include, for example, "light ester HO-MS", "light acrylate HOA-MS (N)", "light acrylate HOA-HH (N)", "light acrylate HOA- Manufactured by Kyoeisha Co., Ltd., trade name), and the like can be used.

The first (meth) acrylic copolymer includes at least one kind of a second constituent unit derived from a monomer having a hydroxy group. The monomer having a hydroxyl group forming the second constituent unit is not particularly limited as far as it is a monomer having at least one hydroxyl group and a polymerizable group capable of forming a copolymer with the first constituent unit and can be appropriately selected from monomer .

There is no particular limitation on the method of introducing the second constituent unit derived from the monomer having a hydroxy group into the first (meth) acrylic copolymer. For example, at least one kind of monomer having a hydroxy group, at least one kind of monomer represented by the formula (1a) and, if necessary, other monomers (preferably at least one kind of alkyl (meth) acrylate) A first (meth) acrylic copolymer containing a first constituent unit represented by the general formula (1) and a second constituent unit derived from a monomer having a hydroxy group in the molecule can be obtained.

Examples of the monomer having a hydroxyl group include monomers having a hydroxyl group and an ethylenically unsaturated bonding group. Specific examples of the monomer having a hydroxyl group include 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 3-hydroxypropyl (meth) acrylate, 4-hydroxybutyl 3-hydroxybutyl (meth) acrylate, 1,1-dimethyl-3-butyl (meth) acrylate, 1,3- (Meth) acrylate, 2-ethyl-3-hydroxyhexyl (meth) acrylate, glycerin mono (meth) acrylate, polypropylene glycol mono (Meth) acrylates such as polyethylene glycol mono (meth) acrylate and poly (ethylene glycol-propylene glycol) mono (meth) acrylate; (Meth) acrylamides such as N-methylol (meth) acrylamide and N-hydroxyethyl (meth) acrylamide; Unsaturated alcohols such as allyl alcohol and methallyl alcohol; And the like.

Among them, the monomer having a hydroxyl group is preferably a (meth) acrylic acid ester having one hydroxyl group and an alkyl group having 2 to 6 carbon atoms, in view of good compatibility with other monomers and copolymerization and good crosslinking reaction with a crosslinking agent , And more preferably 2-hydroxyethyl (meth) acrylate or 4-hydroxybutyl (meth) acrylate.

The content of the second constituent unit derived from the monomer having a hydroxy group in the first (meth) acrylic copolymer is preferably 0.1% by mass or more and 10.0% by mass or less in the total mass of the first (meth) acrylic copolymer, more preferably 2.0% More preferably not less than 8.0% by mass, and still more preferably not less than 2.0% by mass and not more than 5.0% by mass. The content of the structural unit derived from the monomer having a hydroxy group is lower than the lower limit value described above, the occurrence of contamination to the adherend tends to be more effectively suppressed. Further, the content ratio of the structural unit derived from the monomer having a hydroxy group is not more than the upper limit value, so that the conformability (wettability) tends to be better.

The content ratio of the first structural unit and the second structural unit in the first (meth) acrylic copolymer is not particularly limited. From the viewpoint of antistatic property and low staining property to an adherend, the content ratio (first constituent unit / second constituent unit) of the first constituent unit to the second constituent unit in the first (meth) Is preferably 1/10 to 2/1, more preferably 1/5 to 4/3.

The total content of the first constituent unit and the second constituent unit in the first (meth) acrylic copolymer is not particularly limited. From the viewpoint of antistatic property and low staining property to an adherend, the total content of the first constituent unit and the second constituent unit in the first (meth) acrylic copolymer is preferably 1 mass By mass to 15% by mass or less, more preferably 2% by mass or more and 10% by mass or less, still more preferably 3% by mass or more and 8% by mass or less.

It is preferable that the first (meth) acrylic copolymer further comprises at least one third constituent unit derived from alkyl (meth) acrylate in addition to the first constituent unit and the second constituent unit.

The alkyl group in the alkyl (meth) acrylate may be linear or branched. The number of carbon atoms in the alkyl group in the alkyl (meth) acrylate is preferably from 1 to 18, more preferably from 2 to 10, from the viewpoint of adhesiveness.

Specific examples of the alkyl (meth) acrylate include methyl (meth) acrylate, ethyl (meth) acrylate, n-butyl (meth) acrylate, isobutyl (meth) acrylate, (Meth) acrylate, n-decyl (meth) acrylate, n-dodecyl (meth) acrylate, ) Alkyl (meth) acrylates having linear or branched alkyl of 1 to 18 carbon atoms such as stearyl (meth) acrylate and stearyl (meth) acrylate, and derivatives thereof.

The first (meth) acrylic copolymer may contain one or more kinds of the third constituent units derived from alkyl (meth) acrylate, or two or more types thereof. When the first (meth) acrylic copolymer includes two kinds of the third structural units, one of them is a structural unit derived from an alkyl (meth) acrylate having a linear or branched alkyl group having 1 to 5 carbon atoms, Is preferably a structural unit derived from an alkyl (meth) acrylate having a linear or branched alkyl group having 6 to 18 carbon atoms, and one of the alkyl (meth) acrylate having a straight chain alkyl group having 2 to 5 carbon atoms And the other is a structural unit derived from an alkyl (meth) acrylate having a branched alkyl group having 6 to 10 carbon atoms.

When the first (meth) acrylic copolymer comprises a third constituent unit, the content of the third constituent unit is preferably 60 mass% or more and 99.9 mass% or less in the total mass of the first (meth) acrylic copolymer, and 72 More preferably not less than 99.5% by mass, and still more preferably not less than 85% and not more than 99% by mass. If the content of the third constituent unit is above the lower limit value, the conformability (wettability) tends to be better. When the content ratio of the third constituent unit is not more than the upper limit value, the adhesive force at the time of high-speed peeling does not become too large, and workability at high-speed peeling tends to be better.

The first (meth) acrylic copolymer may further contain other constituent units other than the first constituent unit, the second constituent unit and the third constituent unit, if necessary. Examples of the monomer forming the other constituent unit include (meth) acrylate having a cyclic group such as cyclohexyl (meth) acrylate and benzyl (meth) acrylate; Saturated fatty acid vinyl esters such as aliphatic vinyl monomers such as vinyl formate, vinyl acetate, vinyl propionate, vinyl versatate (trade name, vinyl neodecanoate); Aromatic vinyl monomers such as styrene,? -Methyl styrene, and vinyl toluene; Cyanovinyl monomers such as acrylonitrile and methacrylonitrile; Dimethyl maleate, di-n-butyl maleate, di-2-ethylhexyl malate, di-n-octyl malate, dimethyl fumarate, di-n-butyl fumarate, Diester monomers of maleic acid or fumaric acid such as di-n-octyl fumarate; And the like.

Further, as the monomer forming the other constituent unit, a monomer having at least one functional group in addition to one radically polymerizable group in the molecule and a monomer different from a monomer forming the first constituent unit and a monomer forming the second constituent unit , &Quot; functional monomer &quot;). Examples of the functional monomer include monomers having a functional group such as a carboxyl group, an amide group, a substituted or unsubstituted amide group, a substituted or unsubstituted amino group, an alkoxy group, an epoxy group, a mercapto group or a silicon-containing group. Monomers having two or more radically polymerizable groups in the molecule can also be used as the monomers forming the other constituent units.

Specific examples of these functional monomers include carboxyl groups such as (meth) acrylic acid, itaconic acid, and maleic anhydride, monomers containing anhydride groups thereof; (Meth) acrylamide, diacetone acrylamide, N-methylol (meth) acrylamide, Nn-butoxymethyl (meth) acrylamide, N-isobutoxymethyl ) Acrylamide, N-methyl (meth) acrylamide, and other substituted or unsubstituted amide group-containing monomers; Substituted or unsubstituted amino group-containing monomers such as aminoethyl (meth) acrylate, N, N-dimethylaminoethyl (meth) acrylate and N, N-diethylaminoethyl (meth) acrylate; Methoxyethyl (meth) acrylate, 2-methoxyethyl (meth) acrylate, 2-ethoxyethyl (meth) (Meth) acrylate, methoxypolyethylene glycol mono (meth) acrylate, methoxypolyethylene glycol monomethacrylate, and other alkoxy groups such as methoxyethoxyethyl (meth) acrylate, 2-n-butoxyethoxyethyl Monomers; Epoxy group-containing monomers such as glycidyl (meth) acrylate, glycidyl allyl ether, and glycidyl methallyl ether; Mercapto group-containing monomers such as allyl mercaptan; Vinyl trichlorosilane, vinyltribromosilane, vinyltrimethoxysilane, vinyltriethoxysilane, vinyltri-n-propoxysilane, vinyltriisopropoxysilane, vinyltri-n-butoxysilane, vinyltris ( Vinyltriethoxysilane, vinylethoxysiladiol, vinylmethyldiethoxysilane, vinyldimethylsilane, vinyltrimethoxysilane, vinyltrimethoxysilane, vinyltrimethoxysilane, vinyltrimethoxysilane, vinyltrimethoxysilane, (Meth) acryloxypropyltrimethoxysilane, 3- (meth) acryloxypropyltriethoxysilane, vinyltriethoxysilane, allyltrimethoxysilane, allyltriethoxysilane, 3- (Meth) acryloxypropyltrimethoxysilane, 3- (meth) acryloxypropyltrimethoxysilane, 3- (meth) acryloxypropyltris (2-methoxyethoxy) Propyldimethylmethoxysilane, 2- (meth) acrylamidoethyltriethoxysilane, etc. A monomer having a group containing silicon; And the like.

When the first (meth) acrylic copolymer contains other constituent units, the content of the other constituent units is preferably 30 mass% or less, more preferably 20 mass% or less, in the total mass of the first (meth) acrylic copolymer And more preferably 10 mass% or less. When the content ratio of the other constituent units is not more than the upper limit value, there is a tendency that the adhesive force balance between low-speed peeling and high-speed peeling can be improved.

Furthermore, when the first (meth) acrylic copolymer contains a constituent unit derived from a monomer having a carboxyl group, which is a functional monomer, as the other constituent unit, the content ratio of the constituent unit derived from the monomer having the carboxyl group is preferably 1 ) Acrylic copolymer is preferably 0.5 mass% or less, more preferably 0.2 mass% or less, and further preferably not including it. If the content of the constituent unit derived from the monomer having a carboxyl group is less than the above upper limit value, the antistatic performance tends to be better.

The weight average molecular weight of the first (meth) acrylic copolymer is not particularly limited. The weight average molecular weight (Mw) of the first (meth) acrylic copolymer is preferably 200,000 or more and 1,000,000 or less, more preferably 300,000 or more and 800,000 or less. If the weight average molecular weight (Mw) of the first (meth) acrylic copolymer is not lower than the lower limit value, the occurrence of contamination to an adherend tends to be more effectively suppressed. In addition, when the weight average molecular weight (Mw) of the first (meth) acrylic copolymer is not more than the upper limit value, the compatibility (wettability) tends to be better.

The dispersion degree (Mw / Mn), which is the ratio of the weight average molecular weight (Mw) to the number average molecular weight (Mn), of the first (meth) acrylic copolymer is preferably 20 or less, more preferably 15 or less, Is more preferable. When the value of the degree of dispersion (Mw / Mn) is not more than the upper limit value, the occurrence of contamination on an adherend tends to be more effectively suppressed.

The weight average molecular weight (Mw) and number average molecular weight (Mn) of the first (meth) acrylic copolymer are values measured by the following methods.

Method of measuring average molecular weight (Mw and Mn)

Measurements are made according to the following (1) to (3).

(1) A solution of a (meth) acrylic copolymer is applied to a release paper and dried at 100 DEG C for 2 minutes to obtain a film-like (meth) acrylic copolymer.

(2) Using the film-like (meth) acrylic copolymer obtained in the above (1) and tetrahydrofuran, a sample solution having a solid content concentration of 0.2 mass% is obtained.

(3) The weight average molecular weight (Mw) and the number average molecular weight (Mn) of the (meth) acrylic copolymer as the standard polystyrene reduced value are measured by gel permeation chromatography (GPC) under the following conditions.

(Condition)

GPC : HLC-8220 GPC (manufactured by Tosoh Corporation)

column : Using 4 TSK-GEL GMHXL

Mobile phase solvent : Tetrahydrofuran

Flow rate : 0.6 mL / min

Column temperature : 40 ° C

The content of the first (meth) acrylic copolymer in the pressure-sensitive adhesive composition may be appropriately selected depending on the purpose and the like. The content of the first (meth) acrylic copolymer is preferably 80 mass% or more and 99 mass% or less, more preferably 85 mass% or more and 99 mass% or less, and 90 mass% or more and 98 mass% or less in the total solid mass of the pressure- Or less.

The total solid mass refers to the total mass of the residue excluding volatile components such as solvents from the pressure-sensitive adhesive composition.

(Second (meth) acrylic copolymer)

The pressure-sensitive adhesive composition comprises at least one kind of a second (meth) acrylic copolymer (hereinafter also referred to as &quot; resin B &quot;) containing a structural unit having a polyalkyleneoxy group and having a lower molecular weight than the first (meth) . Since the pressure-sensitive adhesive composition contains the second (meth) acrylic copolymer in addition to the first (meth) acrylic copolymer, the pressure-sensitive adhesive composition can achieve more excellent antistatic property.

It is considered that the second (meth) acrylic copolymer contains a constituent unit having a polyalkyleneoxy group and is relatively easy to move in the pressure-sensitive adhesive composition because the molecular weight thereof is smaller than that of the first (meth) acrylic copolymer. By this, it is considered that the surface resistance value of the pressure-sensitive adhesive composition is more effectively lowered and more excellent antistatic property can be achieved.

The second (meth) acrylic copolymer includes at least one type of structural unit having a polyalkyleneoxy group. The polyalkyleneoxy group in the second (meth) acrylic copolymer preferably contains an alkyleneoxy group having 2 to 4 carbon atoms as a constituent unit, more preferably an alkyleneoxy group having 2 to 3 carbon atoms as a constituent unit Do.

The number of alkyleneoxy groups contained in the polyalkyleneoxy group can be appropriately selected depending on the purpose and the like. The number of alkyleneoxy groups to be contained is preferably 20 or more, more preferably 20 to 100, and even more preferably 20 to 50 from the viewpoint of antistatic properties. Since the number of alkyleneoxy groups is 20 or more, the pressure-sensitive adhesive composition can exhibit a more remarkable antistatic effect by combination with an alkali metal salt described later. In addition, the number of alkyleneoxy groups contained in the second (meth) acrylic copolymer is a rational number which is the average value of the number of the constituent units having two or more alkyleneoxy groups.

The terminal portion of the polyalkyleneoxy group in the second (meth) acrylic copolymer may be a hydroxy group or an alkoxy group, and is preferably an alkoxy group from the viewpoint of antistatic properties. When the terminal portion of the polyalkyleneoxy group is an alkoxy group, the number of carbon atoms of the alkoxy group is preferably 1 to 10, more preferably 1 to 5.

The constituent unit having a polyalkyleneoxy group may be derived from a monomer having a polyalkyleneoxy group and a polymerizable group, or may be obtained by introducing a polyalkyleneoxy group into a constituent unit having no polyalkyleneoxy group by a polymer reaction. From the viewpoint of the productivity of the constituent unit having a polyalkyleneoxy group, the constituent unit having a polyalkyleneoxy group is preferably derived from a monomer having a polyalkyleneoxy group and a polymerizable group.

Examples of the monomer having a polyalkyleneoxy group and a polymerizable group include polyethylene glycol (meth) acrylate, methoxypolyethyleneoxy (meth) acrylate, ethoxypolyethyleneoxy (meth) acrylate, polypropylene glycol Polypropylene oxy (meth) acrylate, ethoxy polypropylene oxy (meth) acrylate, and the like. Of these, methoxypolyethylene oxy (meth) acrylate and methoxypolypropyleneoxy (meth) acrylate are preferable, and methoxypolyethylene oxy (meth) acrylate having an ethyleneoxy group content of 20 or more is preferable. More preferably at least one member selected from the group consisting of methoxypolypropyleneoxy (meth) acrylate having a content of acrylate and propyleneoxy groups of 20 or more.

The second (meth) acrylic copolymer may contain constituent units having a polyalkyleneoxy group singly or in combination of two or more.

The content of the constituent unit having a polyalkyleneoxy group in the second (meth) acrylic copolymer is preferably 1% by mass or more and 50% by mass or less based on the total mass of the second (meth) acrylic copolymer from the viewpoint of antistatic property, More preferably 1 mass% or more and 30 mass% or less, and still more preferably 5 mass% or more and 20 mass% or less.

The second (meth) acrylic copolymer preferably contains at least one structural unit derived from alkyl (meth) acrylate in addition to the structural unit having a polyalkyleneoxy group.

The alkyl group in the alkyl (meth) acrylate may be linear or branched. The number of carbon atoms of the alkyl group in the alkyl (meth) acrylate is preferably from 1 to 18, more preferably from 2 to 10, from the viewpoint of antistatic property.

Specific examples of the alkyl (meth) acrylate include methyl (meth) acrylate, ethyl (meth) acrylate, n-butyl (meth) acrylate, isobutyl (meth) acrylate, (Meth) acrylate, n-decyl (meth) acrylate, n-dodecyl (meth) acrylate, ) Alkyl (meth) acrylates having linear or branched alkyl of 1 to 18 carbon atoms such as stearyl (meth) acrylate and stearyl (meth) acrylate, and derivatives thereof.

The second (meth) acrylic copolymer may contain constituent units derived from alkyl (meth) acrylate either singly or in combination of two or more.

When the second (meth) acrylic copolymer contains a constituent unit derived from an alkyl (meth) acrylate, the content ratio of the constituent unit derived from the alkyl (meth) acrylate is preferably the total mass of the second (meth) By mass to 95% by mass or less, more preferably 70% by mass or more and 90% by mass or less, and still more preferably 80% by mass or more and 90% by mass or less. If the content of the constituent unit derived from the alkyl (meth) acrylate is lower than the above lower limit value, the occurrence of contamination to the adherend tends to be more effectively suppressed. If the content of the structural unit derived from alkyl (meth) acrylate is less than the above upper limit value, the surface resistance of the pressure-sensitive adhesive composition is lowered, and the pressure-sensitive adhesive composition tends to have better antistatic properties.

The second (meth) acrylic copolymer may contain, if necessary, a constituent unit having a polyalkyleneoxy group and other constituent units other than the constituent unit derived from alkyl (meth) acrylate. As the other structural unit, the same structural units as the other structural units in the first (meth) alkyl copolymer can be cited, and preferable examples thereof are also the same.

There is no particular limitation as long as the molecular weight of the second (meth) acrylic copolymer is smaller than that of the first (meth) acrylic copolymer. The weight average molecular weight (Mw) of the second (meth) acrylic copolymer is preferably 3,000 or more and 100,000 or less, more preferably 5,000 or more and 60,000 or less, still more preferably 5,000 or more and 20,000 or less. If the weight average molecular weight (Mw) of the second (meth) acrylic copolymer is not lower than the lower limit value, the occurrence of contamination on the adherend tends to be more effectively suppressed. When the weight average molecular weight (Mw) of the second (meth) acrylic copolymer is not more than the upper limit value, the antistatic property tends to be further improved.

The ratio (Mw / Mn) of the weight average molecular weight (Mw) to the number average molecular weight (Mn) of the second (meth) acrylic copolymer is preferably 10 or less, more preferably 7 or less, Is more preferable. If the value of Mw / Mn is not more than the upper limit value, the occurrence of contamination to an adherend tends to be more effectively suppressed. The weight average molecular weight (Mw) and number average molecular weight (Mn) of the second (meth) acrylic copolymer are measured in the same manner as in the case of the first (meth) acrylic copolymer.

(Second / first) ratio of the weight average molecular weight to the first (meth) acrylic copolymer of the second (meth) acrylic copolymer is not particularly limited. From the viewpoint of antistatic property, the ratio of the weight average molecular weight to the first (meth) acrylic copolymer of the second (meth) acrylic copolymer is preferably 0.1 or less, and more preferably 0.006 to 0.07.

The content of the second (meth) acrylic copolymer in the pressure-sensitive adhesive composition may be appropriately selected depending on the purpose and the like. The content of the second (meth) acrylic copolymer is preferably 0.05 parts by mass or more and 2.0 parts by mass or less, more preferably 0.1 parts by mass or more and 1.5 parts by mass or less, based on 100 parts by mass of the first (meth) More preferably not more than 1.0 part by mass. When the content of the second (meth) acrylic copolymer is 0.05 parts by mass or more based on 100 parts by mass of the first (meth) acrylic copolymer, a more excellent antistatic effect tends to be obtained. When the content of the second (meth) acrylic copolymer is 2.0 parts by mass or less based on 100 parts by mass of the first (meth) acrylic copolymer, contamination of the adherend tends to be more effectively suppressed.

The first (meth) acrylic copolymer and the second (meth) acrylic copolymer (hereinafter collectively referred to as &quot; copolymer &quot;) may be obtained by polymerizing a mixture of monomers capable of forming constituent units contained in these copolymers Can be manufactured. The method of polymerizing the copolymer is not particularly limited and may be appropriately selected from known methods such as solution polymerization, emulsion polymerization and suspension polymerization. Among them, it is preferable to polymerize by the solution polymerization method in that a copolymer obtained by polymerization is used to prepare the pressure-sensitive adhesive composition of the present invention and the treatment process is relatively simple and can be performed in a short time.

The solution polymerization is generally carried out by a known method such as a method in which a predetermined organic solvent, a monomer, a polymerization initiator, and a chain transfer agent, which is optionally used, are charged in a polymerization vessel and heated and stirred at a reflux temperature of an organic solvent in a nitrogen stream for several hours Can be used.

The weight average molecular weight and the degree of dispersion of the first (meth) acrylic copolymer and the second (meth) acrylic copolymer can be easily controlled by the reaction temperature, time, solvent amount, type and amount of the catalyst.

Examples of the organic solvent for polymerization used in the polymerization of the first (meth) acrylic copolymer and the second (meth) acrylic copolymer include benzene, toluene, ethylbenzene, n-propylbenzene, t-butylbenzene, o- Aromatic hydrocarbons such as xylene, p-xylene, tetralin, decalin and aromatic naphtha; aliphatic or alicyclic hydrocarbons such as n-hexane, n-heptane, n-octane, isooctane, n-decane, dipentene, petroleum spirit, petroleum naphtha and terphenyl; Esters such as ethyl acetate, n-butyl acetate, n-amyl acetate, 2-hydroxyethyl acetate, 2-butoxyethyl acetate, 3-methoxybutyl acetate and methyl benzoate; Ketones such as acetone, methyl ethyl ketone, methyl isobutyl ketone, isophorone, cyclohexanone, and methylcyclohexanone; Glycol ethers such as ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monobutyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether and diethylene glycol monobutyl ether; Alcohols such as methyl alcohol, ethyl alcohol, n-propyl alcohol, isopropyl alcohol, n-butyl alcohol, isobutyl alcohol, s-butyl alcohol and t-butyl alcohol; And the like. Each of these organic solvents may be used alone or in combination of two or more.

As the polymerization initiator, it is possible to use organic peroxides, azo compounds and the like that can be used in ordinary solution polymerization methods. Examples of the organic peroxide include t-butyl hydroperoxide, cumene hydrooxide, dicumyl peroxide, benzoyl peroxide, lauroyl peroxide, caproyl peroxide, diisopropyl peroxy dicarbonate, di- Di-t-butylperoxy cyclohexyl) propane, 2,2-bis (4,4-di-t-amylperoxy) Bis (4,4-di-α-cumylperoxycyclohexyl) propane, 2-ethylhexyloxycyclohexyl) propane, , 2-bis (4,4-di-t-butylperoxycyclohexyl) butane, and 2,2-bis (4,4-di-t-octylperoxycyclohexyl) butane. Examples of the azo compound include 2,2'-azobisisobutyronitrile, 2,2'-azobis-2,4-dimethylvaleronitrile, 2,2'-azobis-4-methoxy- 4-dimethylvaleronitrile, and the like.

The chain transfer agent is not usually used in the production of the first (meth) acrylic copolymer and the second (meth) acrylic copolymer. However, the chain transfer agent is preferably used in an amount not deteriorating the object and effect of the present invention It is possible. Examples of the chain transfer agent include cyanoacetic acid; Alkyl esters of 1 to 8 carbon atoms in cyanoacetic acid; Bromoacetic acid; Alkyl esters of bromoacetic acid having 1 to 8 carbon atoms; Aromatic compounds such as anthracene, phenanthrene, fluorene, and 9-phenylfluorene; aromatic nitro compounds such as p-nitroaniline, nitrobenzene, dinitrobenzene, p-nitrobenzoic acid, p-nitrophenol and p-nitrotoluene; Benzoquinone derivatives such as benzoquinone and 2,3,5,6-tetramethyl-p-benzoquinone; Borane derivatives such as tributylborane; Halogenated compounds such as carbon tetrabromide, carbon tetrachloride, 1,1,2,2-tetrabromoethane, tribromoethylene, trichlorethylene, bromotrichloromethane, tribromomethane and 3-chloro-1- Hydrocarbons; Aldehydes such as chloral and furaldehyde; Alkylmercaptans having 1 to 18 carbon atoms; Aromatic mercaptans such as thiophenol and toluene mercaptan; Mercaptoacetic acid, alkyl esters having 1 to 10 carbon atoms in mercaptoacetic acid; Hydroxyalkylmercaptans having 1 to 12 carbon atoms; Terpenes such as pinene and terpinolene; And the like.

The polymerization temperature is generally in the range of about 30 캜 to 180 캜.

In the production of the first (meth) acrylic copolymer and the second (meth) acrylic copolymer, a purification step for purifying the polymerized product obtained by the polymerization reaction may be provided. In the case where an unreacted monomer is contained in the polymer obtained by the solution polymerization method or the like by the purification process, the monomer may be excluded. The purification process can be suitably selected from commonly used purification methods. For example, it is possible to purify by the reprecipitation method using methanol or the like.

[Polyether-modified silicone]

The pressure-sensitive adhesive composition contains at least one kind of polyether-modified silicone (hereinafter also referred to as &quot; specific polysiloxane compound &quot;) having a hydroxyl group at the polyether terminal. Since the polyether-modified silicone has a hydroxy group at the polyether terminal, the pressure-sensitive adhesive composition exhibits excellent antistatic properties and can effectively inhibit the contamination of the adherend.

When the specific polysiloxane compound has a polyalkyleneoxy group whose terminal is a hydroxyl group in the molecule, the antistatic property is effectively exhibited. This is because, for example, a specific polysiloxane compound is unevenly distributed in the vicinity of the surface of the pressure-sensitive adhesive layer derived from the pressure-sensitive adhesive composition, so that a polyalkyleneoxy group interacting with the alkali metal salt is present in the vicinity of the surface of the pressure- And the surface resistance value is lowered.

Generally, when a polyether-modified silicone having a hydroxyl group at the polyether terminal is contained as the polysiloxane compound in the pressure-sensitive adhesive composition, the effect of lowering the surface resistance of the pressure-sensitive adhesive composition tends to be insufficient. However, in the present invention, the surface resistance value of the pressure-sensitive adhesive composition can be sufficiently lowered by containing the first (meth) acrylic copolymer containing the first constituent unit represented by the general formula (1). On the other hand, in the (meth) acrylic copolymer containing a constituent unit having a carboxyl group derived from (meth) acrylic acid or the like, it is difficult to sufficiently lower the surface resistance value of the pressure-sensitive adhesive composition. Furthermore, it is considered that the first (meth) acrylic copolymer contains a second constituent unit derived from a monomer having a hydroxyl group, thereby more effectively reducing the surface resistance value of the pressure-sensitive adhesive composition.

The specific polysiloxane compound is preferably a polysiloxane compound containing a structural unit derived from a dialkylsiloxane and a structural unit derived from an alkyl (hydroxypolyalkyleneoxy) siloxane from the viewpoints of antistatic property and low staining property to an adherend .

The alkyl group in the dialkylsiloxane preferably has 1 to 4 carbon atoms, and more preferably 1.

The alkyleneoxy group in the alkyl (hydroxypolyalkyleneoxyalkyl) siloxane preferably has 2 to 4 carbon atoms, more preferably 2 to 3 carbon atoms. The number of alkyleneoxy groups contained in the alkyl (hydroxypolyalkyleneoxyalkyl) siloxane is preferably 1 to 100, more preferably 10 to 100. The alkyl group in the alkyl (hydroxypolyalkyleneoxyalkyl) siloxane preferably has 1 to 4 carbon atoms.

When the specific polysiloxane compound includes a structural unit derived from a dialkylsiloxane and a structural unit derived from an alkyl (hydroxypolyalkyleneoxy) siloxane, the number of structural units derived from a dialkylsiloxane is preferably 100 or less , More preferably from 1 to 80. The number of structural units derived from an alkyl (hydroxypolyalkyleneoxyalkyl) siloxane is preferably 2 to 100, more preferably 2 to 80.

The specific polysiloxane compound is preferably a polysiloxane compound represented by the following general formula (3) from the viewpoints of adhesiveness, antistatic property and low staining property to an adherend.

In the general formula (3), p represents the number of repeating units of dimethylsiloxane structural units and is a number of 0 to 100. and q is the number of repeating units of the polypropylene siloxane structural unit having a polyoxyethylene group, and is a number of 2 to 100. Also, a represents the number of repeating units of ethyleneoxy structural units and the number of 1 to 100, respectively. Here, when the compound represented by the general formula (3) is an aggregate of a plurality of compounds, p, q and a are rational numbers as an average value as an aggregate of the compounds.

The repeating number a of the polyethyleneoxy structural unit is a number of 1 to 100, preferably 10 to 100. When a is 1 or more, sufficient conductivity is obtained and the antistatic effect tends to be improved. When a is 100 or less, compatibility with other components constituting the pressure-sensitive adhesive composition is improved, and the transparency of the pressure-sensitive adhesive layer tends to be further improved.

The repeating number p of the dimethylsiloxane structural unit is preferably a number of 0 to 100, and is preferably a number of 1 to 80. When p is 0 or more, the antistatic effect tends to be improved. When p is 100 or less, compatibility with other components constituting the pressure-sensitive adhesive composition is improved, and the transparency of the pressure-sensitive adhesive layer tends to be improved.

Furthermore, the repeating number q of the structural units of methylpropylene siloxane is preferably 2 to 100, and more preferably 2 to 80. When q is 2 or more, sufficient conductivity is obtained and the antistatic effect tends to be improved. When q is 100 or less, compatibility with other components constituting the pressure-sensitive adhesive composition is improved, and the transparency of the pressure-sensitive adhesive layer tends to be improved.

The specific weight average molecular weight of the specific polysiloxane compound is not particularly limited. For example, the specific polysiloxane compound may have a weight average molecular weight of 5,000 or more and 20,000 or less, preferably 6,000 or more and 15,000 or less.

The HLB value of the specific polysiloxane compound is not particularly limited, but is preferably 5 or more and less than 16, more preferably 7 or more and 15 or less from the viewpoints of compatibility with a resin, surface ellipticity and adhesiveness.

The HLB value is a measure of the balance between hydrophilicity and hydrophobicity of a specific polysiloxane compound (surfactant). In the present invention, it is obtained according to the definition of the Griffin method calculated by the following formula 1. When the specific polysiloxane compound is a commercial product, the catalog data is preferentially adopted.

[Equation 1]

{(Total of food in hydrophilic part) / (molecular weight of surfactant)} x 20

The specific polysiloxane compound has a methylpropylene siloxane structural unit having a dimethylsiloxane structural unit and a polyoxyethylene group in the molecule. Each of these structural units may constitute a block copolymer or constitute a random copolymer.

Specific examples of the specific polysiloxane compound represented by the general formula (3) include SF-8428, FZ-2162, SH-3773M (manufactured by Toray Dow Corning Co., Ltd.) .

The specific polysiloxane compound may be selected from commercially available products as described above, or may be obtained by grafting an organic compound having an unsaturated bond and a polyoxyethylene group to the dimethylpolysiloxane main chain having silicon hydride by a hydrosilylation reaction.

The content of the specific polysiloxane compound in the pressure-sensitive adhesive composition is preferably 0.05 parts by mass or more and 0.5 parts by mass or less, more preferably 0.05 parts by mass or more and 0.4 parts by mass or less with respect to 100 parts by mass of the first (meth) acrylic copolymer, more preferably 0.05 mass And more preferably not more than 0.3 part by mass.

When the content of the specific polysiloxane compound is not less than the above lower limit value, the antistatic effect when the surface protective film is peeled can be more effectively obtained. In addition, when the content of the specific polysiloxane compound is not more than the upper limit value, the occurrence of contamination (fogging) on the adherend is suppressed and the compatibility with the acrylic copolymer is lowered and the occurrence of cloudiness can be suppressed.

In addition to the polysiloxane compound represented by the general formula (3), the pressure-sensitive adhesive composition may contain a dimethylpolysiloxane compound having a structure different from that of the general formula (3) and containing a polyethyleneoxy group within a range not to impair the effect of the present invention.

Examples of the dimethylpolysiloxane compound having a structure different from that of the general formula (3) and containing a polyethyleneoxy group include compounds in which the terminal of the polyethyleneoxy group is an alkoxy group or an acyloxy group, polyoxyethylene groups are included in the main chain or terminal And the like.

FZ-2207 "," FZ-2104 "," FZ-2110 "," FZ-2203 "," FZ- L-7001 "," L-7002 "," SF-8427 "," SH-3749 "and" SH-8400 "(manufactured by Toray Dow Co., Ltd.).

When the pressure-sensitive adhesive composition has a structure different from that of the general formula (3) and contains a dimethylpolysiloxane compound having a polyethyleneoxy group, the content thereof is preferably 0.05 mass% or less, more preferably 0.03 mass% or less, in the total mass of the polysiloxane compound More preferable.

[Alkali metal salt]

The pressure-sensitive adhesive composition contains at least one alkali metal salt. The alkali metal salt is not particularly limited as long as it is a metal salt having lithium ion (Li ⁺ ), sodium ion (Na ⁺ ), potassium ion (K ⁺ ), rubidium (Rb ⁺ ) or the like as a cation.

Specifically, the alkali metal salt includes a cation such as Li ⁺ , Na ⁺ , K ⁺ and a cation such as Cl ^- , Br ^- , I ^- , BF ₄ ^- , PF ₆ ^- , SCN ^- , ClO ₄ ^- , CF ₃ SO ₃ ^- ₃ SO ₂ ) ₂ N ^- , (C ₂ F ₅ SO ₂ ) ₂ N ^- , (CF ₃ SO ₂ ) ₃ C ^-, and the like are suitably used.

Among these alkali metal salts in view of anti-static _{LiBr, LiI, LiBF 4, LiPF} 6, LiSCN, LiClO 4, LiCF 3 SO 3, Li (CF 3 SO 2) 2 N, Li (C 2 F 5 SO 2) 2 N, and Li (CF ₃ SO ₂ ) ₃ C are preferably used.

Particularly, the alkali metal salt is preferably LiCF ₃ SO ₃ , Li (CF ₃ SO ₂ ) ₂ N, Li (C ₂ F ₅ SO ₂ ) ₂ N, Li (CF ₃ SO ₂ ) ₃ C and the like in terms of antistatic effect and metal corrosion resistance (CF ₃ SO ₂ ) ₂ N and Li (C ₂ F ₅ SO ₂ ) ₂ N are preferable, and at least one kind of lithium salt selected from the group consisting of LiCF ₃ SO ₃ , Li More preferable.

These alkali metal salts may be used singly or in combination of two or more kinds.

The content of the alkali metal salt in the pressure-sensitive adhesive composition is preferably 0.005 mass parts or more and 0.6 mass parts or less, more preferably 0.005 mass parts or more and 0.3 mass parts or less per 100 mass parts of the first (meth) acrylic copolymer, more preferably 0.01 mass parts or less Or more and 0.2 parts by mass or less.

The content of the alkali metal salt is 0.005 parts by mass or more based on 100 parts by mass of the first (meth) acrylic copolymer, whereby sufficient charging characteristics can be obtained. On the other hand, since the content of the alkali metal salt is 0.6 parts by mass or less based on 100 parts by mass of the first (meth) acrylic copolymer, an antistatic effect on the content is sufficiently obtained.

The mass ratio (specific polysiloxane compound / alkali metal salt) of the specific polysiloxane compound to the alkali metal salt in the pressure-sensitive adhesive composition is preferably 0.1 or more and 5 or less, more preferably 0.5 or more and 4 or less from the viewpoints of antistatic effect and stickiness.

The total content of the specific polysiloxane compound and the alkali metal salt in the pressure-sensitive adhesive composition is preferably from 0.10 parts by mass to 1.00 parts by mass, more preferably from 0.10 parts by mass to 0.50 parts by mass, based on 100 parts by mass of the first (meth) acrylic copolymer Do.

[Polyisocyanate compound]

The pressure-sensitive adhesive composition preferably further comprises at least one polyisocyanate compound in addition to the essential components. The crosslinking reaction between the polyisocyanate compound and the first (meth) acrylic copolymer and the specific polysiloxane compound improves the adhesion and the low staining property to the adherend in a balanced manner.

Examples of the polyisocyanate compound include aromatic polyisocyanate compounds such as xylylene diisocyanate, diphenylmethane diisocyanate, triphenylmethane triisocyanate and tolylene diisocyanate; Aliphatic or alicyclic polyisocyanate compounds such as hexamethylene diisocyanate, isophorone diisocyanate and hydrogenated products of aromatic polyisocyanate compounds thereof; Dimer or trimer of these polyisocyanate compounds; And adducts of these polyisocyanate compounds and polyol compounds such as trimethylolpropane. Among these polyisocyanate compounds, hexamethylene diisocyanate and hexamethylene diisocyanate are preferably at least one selected from the group consisting of dimers, trimesters and adducts, and trimer of hexamethylene diisocyanate is particularly preferable.

These polyisocyanate compounds may be used alone or in combination of two or more.

Examples of the polyisocyanate compound include "Colonate HX", "Colonate HL-S", "Colonate 2234", "Aquanate 200", "Aquanate 210" (available from Nippon Polyurethane Co., Dyun Module N3300 &quot;, &quot; Desmodule N3400 &quot; manufactured by Sumitomo Bayer Urethane Co., Ltd., Dyuranate E-405-80T, Dyuranate 24A-100, Dyuranate TSE- Manufactured by Mitsui Takeda Chemical Co., Ltd.), "Takenate D-110N", "Takenate D-120N", "Takenate M-631N" and "MT- Commercially available ones can be suitably used.

The content of the polyisocyanate compound is preferably 0.1 parts by mass or more and 10 parts by mass or less, more preferably 0.5 parts by mass or more and 5 parts by mass or less based on 100 parts by mass of the first (meth) acrylic copolymer.

If necessary, a curing catalyst such as dibutyltin dilaurate may be further added to the pressure-sensitive adhesive composition.

In addition to the first (meth) acrylic copolymer, the specific polysiloxane compound and the alkali metal salt described above, the pressure-sensitive adhesive composition may suitably contain, if necessary, a weather-resistant stabilizer, a tackifier, a plasticizer, a softener, a peeling aid, a dye, a pigment, an inorganic filler, &Lt; / RTI &gt;

&Lt; Optical member surface protective film &

The optical member surface protective film of the present invention comprises a polyester base material and a pressure-sensitive adhesive layer provided on the polyester base material and derived from the pressure-sensitive adhesive composition.

Since the pressure-sensitive adhesive layer is derived from the pressure-sensitive adhesive composition, a pressure-sensitive adhesive layer excellent in both tackiness, suppressed generation of static electricity due to peeling electrification, and low staining on an adherend can be formed.

The base material used in the optical member surface protective film of the present invention is not particularly limited as long as an adhesive layer can be formed on the base material.

The base material is preferably a polyester resin, an acetate resin, a polyether sulfone resin, a polycarbonate resin, a polyamide resin, a polyimide resin, a polyolefin resin, an acrylic resin And the like. Among them, a polyester resin is preferable as the base material from the viewpoint of surface protection performance, and a polyethylene terephthalate resin is particularly preferable in view of practicality.

The thickness of the base material may be generally 500 mu m or less, preferably 5 mu m to 300 mu m, and more preferably 10 mu m to 200 mu m or so.

An antistatic layer may be provided on one side or both sides of the base material for the purpose of preventing electrification upon peeling. The surface of the base material on the side where the pressure sensitive adhesive layer is provided may be subjected to corona discharge treatment or the like in order to improve the adhesion with the pressure sensitive adhesive layer.

On the base material, a pressure-sensitive adhesive layer derived from the pressure-sensitive adhesive composition is provided.

As a method for forming the pressure-sensitive adhesive layer, there can be mentioned, for example, a method in which a pressure-sensitive adhesive composition comprising a polyisocyanate compound is directly or optionally diluted with an appropriate solvent, applied directly to a surface protective base film (base material) Can be adopted.

Further, a pressure-sensitive adhesive composition containing a polyisocyanate compound, for example, is applied on a release sheet made of a suitable film such as a paper subjected to releasing treatment by a silicone resin or the like or a suitable polyester film, followed by heating and drying to form a pressure- And then the pressure sensitive adhesive layer side of the release sheet is pressed against the surface protection base film (base material) to transfer the pressure sensitive adhesive layer onto the protective film.

In the present invention, the pressure-sensitive adhesive layer is preferably a pressure-sensitive adhesive layer formed by crosslinking the first (meth) acrylic copolymer and the specific polysiloxane compound with the polyisocyanate compound contained in the pressure-sensitive adhesive composition. As a result, the tackiness of the pressure-sensitive adhesive layer and the low staining property to the adherend are further improved.

The conditions for crosslinking the first (meth) acrylic copolymer and the specific polysiloxane compound with the polyisocyanate compound are not particularly limited.

The pressure-sensitive adhesive layer has a sufficient adhesive strength to a large optical member such as that used for a liquid crystal display screen of, for example, 20 inches or more (adhesive force at low-speed peeling is sufficiently large) and can be easily peeled off at high- It is preferable that the adhesive strength is not increased) and that the conformability is good (the cutting edge does not rise up when cut).

That is, the adhesive force of the 180-degree peel to the optical member of the pressure-sensitive adhesive composition at 23 ° C is preferably 0.05 N / 25 mm or more at a peeling speed of 0.3 m / min (low-speed peeling) More preferably 0.06 N / 25 mm or more.

When the pressure-sensitive adhesive composition has an adhesive strength of 0.05 N / 25 mm or more at low speed peeling to the optical member, occurrence of turning or misalignment is suppressed.

Further, when the adhesive force of the pressure-sensitive adhesive composition to the optical member is increased, the workability at the time of high-speed peeling at a large area is lowered, so that the adhesive force (peeling force) at a peeling speed of 30 m / And more preferably less than 1.2 N / 25 mm.

Further, since the optical member may be damaged when the surface protective film is sufficiently peeled off, the pressure-sensitive adhesive composition of the present invention preferably has an absolute value of the peeling electrification voltage of 0.9 kV or less at 30 m / min of peeling on the anti- More preferably 0.4 kV or less, and still more preferably 0.35 kV or less.

It is also preferred from the standpoint of preventing the charging of the film side at the time of peeling the surface protective film is less than the surface resistance of the pressure-sensitive adhesive layer is 1.0E + 12 (Ω / □) (1.0 × 10 12 Ω / □).

The thickness of the pressure-sensitive adhesive layer formed on the base material can be appropriately set in accordance with the adhesive force required for the surface protective film and the surface roughness of the optical member. The thickness of the pressure-sensitive adhesive layer formed on the base material is generally from 1 탆 to 100 탆, preferably from 5 탆 to 50 탆, and more preferably from 15 탆 to 30 탆.

The optical member surface protective film thus obtained is laminated on the surface of the optical member to protect the surface of the optical member from being contaminated or damaged. When the optical member is processed into a liquid crystal display plate or the like, the protective film is laminated on the optical member And is subjected to heating and pressurizing treatments such as autoclave treatment and high temperature aging treatment as required, and is peeled off from the optical member at the stage where the surface protection is not needed, Removed.

Example

Hereinafter, the present invention will be described concretely with reference to Examples, but the present invention is not limited to these Examples. Unless otherwise noted, "parts" and "%" are by mass.

(Production Example 1)

- Preparation of a first (meth) acrylic copolymer 1-

20 parts of ethyl acetate and 10 parts of toluene were placed in a reactor equipped with a stirrer, a thermometer, a stirrer, a nitrogen inlet tube and a reflux condenser and 50 parts of butyl acrylate (BA) as a monomer, 2-ethylhexyl acrylate (2EHA) , 3 parts of 4-hydroxybutyl acrylate (4HBA) as a monomer having a hydroxy group and 1 part of Aronix M-5300 (M5300, manufactured by Toagosei Co., Ltd.) as a monomer represented by the general formula (1a) Respectively. 25% of the monomer mixture was added to the reaction vessel. Subsequently, air in the reaction vessel was replaced with nitrogen gas, and 0.02 part of azobisbutyronitrile (hereinafter referred to as AIBN) as a polymerization initiator was added thereto. The temperature of the mixture in the reaction vessel was raised to 70 캜 to initiate the initial reaction. After the initial reaction was almost completed, a mixture of 75% of the remaining monomer mixture and 20 parts of ethyl acetate, 10 parts of toluene and 0.2 part of AIBN was added in order and reacted for about 2 hours, followed by further reaction for 2 hours. Thereafter, a solution prepared by dissolving 0.25 part of AIBN in 25 parts of toluene was added dropwise over 1 hour and further reacted for 1.5 hours. After completion of the reaction, the reaction mixture was diluted with 125 parts of toluene to obtain a first (meth) acrylic copolymer solution A-1 having a solid content of 35%.

The first (meth) acrylic copolymer thus obtained had a weight average molecular weight (Mw) of 530,000 and a dispersion degree (Mw / Mn) of 8.2.

(Production Example 2)

- Preparation of first (meth) acrylic copolymer 2-

A first (meth) acrylic copolymer solution A-2 was prepared in the same manner as in Preparation Example 1 except that the blending amount of 2-ethylhexyl acrylate (2EHA) was changed to 45 parts and the blending amount of M5300 was changed to 2 parts in Production Example 1 .

The weight average molecular weight (Mw) of the obtained first (meth) acrylic copolymer was 5,200 and the dispersion degree (Mw / Mn) was 8.0.

(Production Example 3)

- Preparation of first (meth) acrylic copolymer 3-

A first (meth) acrylic copolymer solution A-3 was prepared in the same manner as in Preparation Example 1 except that the compounding amount of 2-ethylhexyl acrylate (2EHA) was changed to 43 parts and the blending amount of M5300 was changed to 4 parts in Production Example 1 .

The first (meth) acrylic copolymer thus obtained had a weight average molecular weight (Mw) of 480,000 and a dispersion degree (Mw / Mn) of 7.7.

(Production Example 4)

- Preparation of first (meth) acrylic copolymer 4-

(Meth) acrylic copolymer (1) was prepared in the same manner as in Production Example 1, except that 1 part of a light acrylate HO-AMS (HOAMS, manufactured by Kyoe Kagaku KK) was used instead of M5300 as a monomer represented by the general formula To prepare Coalescence Solution A-4.

The first (meth) acrylic copolymer thus obtained had a weight average molecular weight (Mw) of 500,000 and a dispersion degree (Mw / Mn) of 8.4.

(Production Example 5)

- Preparation of first (meth) acrylic copolymer 5-

Except that the amount of butyl acrylate (BA) was changed to 96 parts and the amount of 2-ethylhexyl acrylate (2EHA) was changed to 0 part in Production Example 1 to prepare a first (meth) acrylic copolymer solution A -5.

The first (meth) acrylic copolymer thus obtained had a weight average molecular weight (Mw) of 540,000 and a dispersion degree (Mw / Mn) of 6.9.

(Production Example 6)

- Preparation of first (meth) acrylic copolymer 6-

Except that the amount of butyl acrylate (BA) was changed to 0 part and the amount of 2-ethylhexyl acrylate (2EHA) was changed to 96 parts in Production Example 1 to obtain a first (meth) acrylic copolymer solution A -6.

The first (meth) acrylic copolymer thus obtained had a weight average molecular weight (Mw) of 4,100 and a dispersion degree (Mw / Mn) of 8.3.

(Production Example 7)

- (meth) acryl Copolymer C1-

(Meth) acrylic copolymer solution C-1 was prepared in the same manner as in Production Example 1, except that the blending amount of 2-ethylhexyl acrylate (2EHA) was changed to 47 parts and M5300 was not blended (0 part) in Production Example 1 Respectively.

The resulting (meth) acrylic copolymer had a weight average molecular weight (Mw) of 530,000 and a dispersion degree (Mw / Mn) of 8.9.

(Preparation Example 8)

- (meth) acryl Copolymer &lt; RTI ID = 0.0 &gt; C2-

(Meth) acrylic copolymer solution C-2 was produced in the same manner as in Production Example 1 except that the blending amount of 2-ethylhexyl acrylate (2EHA) was changed to 46.5 parts and the acrylic acid (AA) was used in place of M5300 in Production Example 1 Respectively.

The resulting (meth) acrylic copolymer had a weight average molecular weight (Mw) of 500,000 and a dispersion degree (Mw / Mn) of 8.3.

(Preparation Example 9)

- (meth) acryl Copolymer C3-

(Meth) acrylic copolymer solution C-3 (1) was prepared in the same manner as in Production Example 1 except that the blending amount of 2-ethylhexyl acrylate (2EHA) was changed to 46.5 parts and the methacrylic acid (MAA) .

The resulting (meth) acrylic copolymer had a weight average molecular weight (Mw) of 490,000 and a dispersion degree (Mw / Mn) of 8.3.

(Preparation Example 10)

- Preparation of Second (meth) acrylic Copolymer 1-

In a four-necked flask equipped with a stirrer, a thermometer, a nitrogen gas introducing tube, a condenser and a dropping funnel, n-butyl methacrylate (n-BMA) 90 parts and methoxypolyethylene glycol methacrylate 10 parts as the average value of the number of repeating ethyleneoxy groups, 0.8 parts of AIBN as a polymerization initiator, and 400 parts of ethyl acetate were introduced and nitrogen gas was introduced with gentle stirring. The polymerization temperature was maintained at 70 캜 for 6 hours, To prepare a solution B-1 of a second (meth) acrylic copolymer having a solid content of 20%.

The weight average molecular weight of the obtained second (meth) acrylic copolymer was 7,000.

&Lt; Example 1 >

In a four-necked flask equipped with a stirring wing, a thermometer, a condenser and a dropping funnel, 100 parts by weight of the first (meth) acrylic copolymer solution A-1 (resin A in the table) , 0.4 part of the acrylic copolymer solution B-1 (resin B in the table) in terms of solid content, 0.1 part of SH-3773M (trade name, side chain polyether modified silicone, polyether terminal hydroxyl group, product of Toray Dow Corning Co., Ltd.) as the specific polysiloxane compound , And 0.05 part of LiCF ₃ SO ₃ (LiTFS, manufactured by Morita Kagaku Kogyo KK) were placed in a flask, and the mixture was stirred and mixed at a liquid temperature of 25 ° C for 4.0 hours to obtain a (meth) acrylic copolymer mixed solution.

To this was added, as a polyisocyanate compound, a trade name: Desmodur N3300 (HMDI trimer, solid content: 100% by weight; Manufactured by Sumika Bayer Urethane Co., Ltd.) was added and sufficiently stirred to obtain a pressure-sensitive adhesive composition for a surface protective film (hereinafter, simply referred to as "pressure-sensitive adhesive composition").

This pressure-sensitive adhesive composition had a sufficient pot life.

Using the obtained pressure-sensitive adhesive composition, a surface protective film for test was prepared according to the following method for producing a surface protective film for test, and various physical properties were tested. The obtained results are shown in Table 1.

(1) Preparation of test surface protective film

The pressure-sensitive adhesive composition was applied on a releasing paper surface treated with a silicone type releasing agent so that the coated amount after drying was 20 g / m 2, and dried with a hot air circulating drier at 100 캜 for 60 seconds to form a pressure-sensitive adhesive layer, and then a polyethylene terephthalate (PET) [product name; E5001; The surface of the pressure-sensitive adhesive layer was brought into contact with the surface of the pressure-sensitive adhesive layer, pressed and knitted through a pressure nip roll, and cured for 10 days under an environment of 23 ° C and 50% RH to obtain a test surface protective film.

(2) Measurement of adhesive force

The test surface protective film prepared in the above (1) was cut into 25 mm x 150 mm, the release paper was peeled off from the surface protective film piece, and the antiglare treated polarizing film (trade name: SQ-1852AP-AG6; Manufactured by Sumitomo Chemical Industries, Ltd.] as a test sample.

This test sample was allowed to stand for 24 hours under an environment of 23 占 폚 and 50% RH (conditioning treatment), and thereafter peeled off from the polarizing film in the long side (150 mm) At a peeling speed of 0.3 m / min (low-speed peeling) and at a peeling speed of 30 m / min (high-speed peeling).

(3) Contact angle of water in the pressure-sensitive adhesive layer (stainability evaluation)

The test surface protective film prepared in the above (1) was allowed to stand under the environment of 60 ° C and 90% RH for 48 hours. After standing for 1 hour in an environment of 23 DEG C and 50% RH, the release film was peeled off from the test surface protective film to expose the surface of the pressure-sensitive adhesive layer. After 2 seconds of pure water was dropped onto the surface of the pressure-sensitive adhesive layer, the contact angle of water was measured after 30 seconds by using a contact angle measuring apparatus (Kyowa Interface Science Co., Ltd.: contact angle meter CA-D) .

~ Evaluation Criteria ~

AA: The contact angle was 90 ° or more.

A: The contact angle was 80 DEG or more and less than 90 DEG.

B: The contact angle was 50 ° or more and less than 80 °.

C: The contact angle was less than 50 占.

(4) Measurement of surface resistance value

The release paper was peeled off from the test surface protective film prepared in the above (1), and the surface resistance value of the exposed surface of the pressure-sensitive adhesive layer was measured using a surface resistance measuring device (Advantec: R12704 RESISTIVITY CHAMBER) Thereby evaluating antistatic properties.

~ Evaluation Criteria ~

AA: The surface resistance value was less than 1.0E + 11 (? /?).

A: The surface resistance value was 1.0E + 11 (? /?) And 5.0E + 11 (? /).

B: The surface resistance value was 5.0E + 11 (? /?) And 1.0E + 12 (? /).

C: The surface resistance value was 1.0E + 12 (? /?) Or more.

(5) Peeling Voltage measurement

The test surface protective film prepared in the above (1) was cut into 25 mm x 150 mm, and the surface protective film piece was coated with an antiglare-treated polarizing film (trade name: SQ-1852AP-AG6; Manufactured by Sumitomo Chemical Industries, Ltd.] as a test sample. The sample was allowed to stand (conditioning treatment) under the conditions of 23 ° C and 50% RH for 24 hours, followed by peeling at 180 ° peeling and peeling at a peeling rate of 30 m / min (high-speed peeling condition). The potential (kV) of the polarizing plate surface generated at this time was measured with a potential meter (KSD-0303, manufactured by Kasuga Electric Co., Ltd.) fixed at a position 10 mm from the polarizing plate in the direction perpendicular to the surface. The measurement was carried out in an environment of 23 캜 and 50% RH.

&Lt; Examples 2 to 13 >

A pressure-sensitive adhesive composition for a surface protective film was prepared in the same manner as in Example 1 except that the respective components used in the preparation of the pressure-sensitive adhesive composition for a surface protective film in Example 1 were changed as shown in Tables 1 and 2, Test was carried out. The obtained results are shown in Tables 1 and 2.

&Lt; Comparative Examples 1 to 4 >

A pressure-sensitive adhesive composition for a surface protective film was prepared in the same manner as in Example 1 except that each component used in preparing the pressure-sensitive adhesive composition for a surface protective film in Example 1 was changed as shown in Table 2, . The obtained results are shown in Table 2.

The abbreviations in Tables 1 and 2 are as follows.

BA: butyl acrylate; 2EHA: 2-ethylhexyl acrylate; 4HBA: 4-hydroxybutyl acrylate; M5300: Aronix M-5300, ω-carboxy-polycaprolactone (n≈2) monoacrylate, manufactured by Toagosei Co., Ltd.; HOAMS: product of Kyowa Chemical Co., Ltd., light acrylate HOA-MS (N), 2-acryloyloxyethyl succinate; AA: acrylic acid; MAA: methacrylic acid; n-BMA: n-butyl methacrylate; MePEGMA: methoxypolyethylene glycol methacrylate (the average value of the number of repeating ethyleneoxy groups is 23);

N3300: Death module N3300 [hexamethylene diisocyanate trimer, manufactured by Sumika Bayer Urethane Co., Ltd.];

SH-3773M: manufactured by Toray Dow Corning Co., side chain polyether-modified silicone, polysiloxane compound represented by general formula (3); FZ-2162: product of Toray Dow Corning Co., side chain polyether-modified silicone, polysiloxane compound represented by general formula (3);

SH-8400: a product of Toray Dow Corning Co., side chain polyether-modified silicone;

AS agent: antistatic agent; _{LiTFSl: Li (CF 3 SO 2} ) 2 N; LiTFS: LiCF ₃ SO ₃ .

From Table 1 and Table 2, it can be seen that the pressure-sensitive adhesive composition of the present invention is excellent in tackiness, suppressed generation of static electricity by peeling electrification, and excellent low staining property of an adherend.

[Compliance Evaluation]

The test surface protective film produced using the pressure-sensitive adhesive composition prepared in Examples 1 to 13 was cut into a size of 200 mm x 150 mm, and then the release film was peeled off and the surface of the pressure-sensitive adhesive layer was coated with an anti- Under the conditions of the center of gravity and the time of spreading by natural gravity was measured. As a result, in all the samples, the time to fully wet to the end portion was excellent in less than 60 seconds.

According to the present invention, it becomes possible to provide a pressure-sensitive adhesive composition capable of achieving a high level of antistatic property and low staining property to an adherend, and an optical member surface protective film using the same.

The disclosure of Japanese Patent Application No. 2012-286049 is incorporated herein by reference in its entirety.

All publications, patent applications, and technical specifications described in this specification are herein incorporated by reference to the same extent as if each individual publication, patent application, and technical specification were specifically and individually indicated to be incorporated by reference.

Claims (6)

A first (meth) acrylic copolymer comprising a first constituent unit represented by the following general formula (1) and a second constituent unit derived from a monomer having a hydroxy group,
A polyether-modified silicone having a hydroxyl group at the polyether terminal,
A pressure-sensitive adhesive composition containing an alkali metal salt.
[Chemical Formula 1]

(In the general formula (1), R ¹ represents a hydrogen atom or a methyl group.) L represents a divalent linking group composed of at least one kind selected from the group consisting of an alkylene group, an arylene group, a carbonyl group and an oxygen atom. The method according to claim 1,
Wherein L in the general formula (1) is at least one selected from the group consisting of a divalent linking group represented by the following general formula (2a) and a divalent linking group represented by the following general formula (2b).
(2)

(In the formulas (2a) and (2b), R ²¹ to R ²⁴ each independently represent an alkylene group having 1 to 12 carbon atoms or an arylene group having 6 to 10 carbon atoms, n denotes a number of 0 to 10, m Represents a number from 1 to 10.) The method according to claim 1 or 2,
Wherein the content of the first constituent unit in the (meth) acrylic copolymer is 0.5% by mass to 5% by mass. The method according to any one of claims 1 to 3,
Wherein the content of the polyether-modified silicone is 0.05 part by mass to 0.50 parts by mass with respect to 100 parts by mass of the (meth) acrylic copolymer. The method according to any one of claims 1 to 4,
(Meth) acrylic copolymer containing a structural unit having a polyalkyleneoxy group and having a molecular weight lower than that of the first (meth) acrylic copolymer. A polyester base material,
An optical member surface protective film provided on the polyester base material and comprising a pressure-sensitive adhesive layer derived from the pressure-sensitive adhesive composition according to any one of claims 1 to 5.