JP6058390B2 - Adhesive composition and optical member surface protective film - Google Patents

Description

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

  In recent years, liquid crystal display devices have been used as screen display devices for various information-related devices such as word processors and notebook personal computers because they are thin and light and consume less power. In such a liquid crystal display plate, an optical member such as a polarizing plate and a retardation plate is used together with a glass cell (liquid crystal cell) containing liquid crystal as a main body.

  These optical members are usually further coated with a surface protective film so that the surface is not contaminated or damaged during each process such as punching, inspection, transportation, and assembly of the liquid crystal display panel. The surface protection film is peeled and removed from the optical member when the surface protection is no longer necessary.

While such a surface protective film is required to protect the surface of the optical member, the surface protective film adheres to the surface to such an extent that the optical member does not deviate or fall off from the surface. In order not to interfere with various inspections such as liquid crystal performance inspection, it must be highly transparent, and there should be no defects in the adhesive layer such as bulge, tunneling, peeling, and the interface between the adhesive layer and the optical member. Is required. When peeling the film from the optical member, in order not to damage the optical member and the liquid crystal cell due to the distortion caused by the peeling, and so as not to cause inconvenience such as the optical member peeling from the liquid crystal cell, It must be easily peelable. Further, when the surface protective film is peeled off, it is required that no residue derived from the surface protective film is formed on the optical member, that is, that the adherence to the adherend (hereinafter also simply referred to as “fouling”) is low.
In recent years, the speed of peeling of the surface protective film tends to be increased for the purpose of improving working efficiency, and workability in high-speed peeling has been required as a characteristic 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, dust or dust is adsorbed on the surface of the optical film, resulting in inconvenience for the product. In addition, when the surface protection film is peeled off, if a large amount of static electricity is generated, the circuit of the display member may be destroyed. Therefore, when the surface protective film is peeled off, good antistatic properties are required.

In relation to the above, an adhesive comprising an acrylic copolymer, a metal salt, and an organopolysiloxane having a polyoxyalkylene group is disclosed, and there is little contamination of the adherend, and less static electricity is generated due to peeling charging. (For example, refer to Patent Document 1).
Also disclosed is an adhesive optical film having an adhesive layer containing an acrylic polymer containing a monomer unit having a specific structure having a carboxyl group, which is crosslinked with a polyfunctional compound. It is said that it is excellent in relaxation (for example, refer patent document 2).
Furthermore, a surface protective film having a pressure-sensitive adhesive layer obtained by externally adding a silicon-containing compound such as polyether-modified polyorganosiloxane to an acrylic pressure-sensitive adhesive is disclosed to suppress the generation of static electricity ( For example, see Patent Document 3).

JP 2009-275128 A JP 2002-277634 A JP 2011-063712 A

However, with the pressure-sensitive adhesives described in Patent Documents 1 to 3, it may be difficult to achieve both high antistatic properties and low contamination.
This invention makes it a subject to provide the adhesive composition which can make antistatic property and the low pollution property with respect to a to-be-adhered body compatible at a high level, and an optical member surface protection film using the same.

Specific means for solving the above problems are as follows.
<1> A first (meth) acrylic copolymer containing a first structural unit represented by the following general formula (1) and a second structural unit derived from a monomer having a hydroxy group, and a polyether It is a pressure-sensitive adhesive composition containing a polyether-modified silicone having a hydroxy group at the terminal and an alkali metal salt.

In general formula (1), R ¹ represents a hydrogen atom or a methyl group. L represents a divalent linking group composed of at least one 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 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). It is an adhesive composition as described in said <1> which is at least 1 type.

In general 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 shows the number of 0-10, m shows the number of 1-10.

<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. It is a thing.

<4> The content of the polyether-modified silicone is 0.05 parts by mass to 0.50 parts by mass with respect to 100 parts by mass of the (meth) acrylic copolymer. It is an adhesive composition as described in any one.

<5> Said <1>-which contains the structural unit which has a polyalkyleneoxy group, and further contains the 2nd (meth) acryl copolymer which is lower molecular weight than said 1st (meth) acryl copolymer. It is an adhesive composition as described in any one of <4>.

<6> A surface of an optical member comprising a polyester base material and a pressure-sensitive adhesive layer provided on the polyester base material and derived from the pressure-sensitive adhesive composition according to any one of <1> to <5>. It is a protective film.

  ADVANTAGE OF THE INVENTION According to this invention, the adhesive composition which can make antistatic property and the low pollution property with respect to a to-be-adhered body compatible on a high level, and an optical member surface protection film using the same can be provided.

In the present specification, a numerical range indicated using “to” indicates a range including the numerical values described before and after “to” as the minimum value and the maximum value, respectively. Further, in the present specification, when referring to the amount of each component in the composition, when there are a plurality of substances corresponding to each component in the composition, the plurality of the components present in the composition unless otherwise specified. It means the total amount of substance.
Furthermore, (meth) acrylate means at least one of acrylate and methacrylate, and phrases such as (meth) acrylic copolymer similar to (meth) acrylate have the same meaning.

<Adhesive composition>
The pressure-sensitive adhesive composition of the present invention comprises a first (meth) acrylic copolymer containing a first structural unit represented by the following general formula (1) and a second structural unit derived from a monomer having a hydroxy group. It contains a polymer, a polyether-modified silicone having a hydroxy group at the end of the polyether, and an alkali metal salt. The pressure-sensitive adhesive composition may further contain other components as necessary.

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

  A first (meth) acrylic copolymer comprising a first structural unit having a specific structure having a carboxy group and a second structural unit derived from a monomer having a hydroxy group, and a polyether By containing a polyether-modified silicone having a hydroxyl group at the terminal and an alkali metal salt, it has both excellent antistatic properties and low contamination to the adherend, and has excellent adhesiveness and reliability. Excellent. Such an adhesive composition can be preferably applied to an optical member surface protective film.

  For example, this can be considered as follows. Since the pressure-sensitive adhesive composition contains a polyether-modified silicone, the alkali metal salt can be localized near the surface of the pressure-sensitive adhesive composition due to the interaction with the alkali metal salt, and exhibits excellent antistatic properties. it is conceivable that. Further, the first (meth) acrylic copolymer interacts with the polyether-modified silicone, so that the surface resistance value of the pressure-sensitive adhesive composition is effectively reduced, and it is considered that more excellent antistatic properties are exhibited. This is considered to be due to the fact that the first (meth) acrylic copolymer has both the first structural unit and the second structural unit having a specific structure. In particular, a (meth) acrylic copolymer containing a structural unit having a carboxyl group derived from (meth) acrylic acid or the like instead of the first structural unit having a specific structure as a structural unit containing a carboxy group has such effects. It is thought that it cannot be obtained sufficiently. Furthermore, the polyether-modified silicone has a hydroxyl group at the end of the polyether, thereby effectively preventing the constituent components of the pressure-sensitive adhesive composition from remaining on the adherend when the pressure-sensitive adhesive is peeled off from the adherend. Therefore, it is thought that the low contamination property with respect to the adherend can be exhibited.

[(Meth) acrylic copolymer]
The pressure-sensitive adhesive composition is a first (meth) acrylic copolymer (containing a first structural unit represented by the general formula (1) and a second structural unit derived from a monomer having a hydroxy group ( Hereinafter, it contains at least one kind of “resin A”. The pressure-sensitive adhesive composition may further contain a (meth) acrylic copolymer different from the first (meth) acrylic copolymer as necessary.
Here, the (meth) acrylic copolymer is 50% by mass or more of all monomer components constituting the copolymer (the monomer constituting the copolymer may be simply referred to as a copolymerization component). , Preferably 90 mass% or more means the copolymer which is a (meth) acryl monomer.

(First (meth) acrylic copolymer)
The first (meth) acrylic copolymer contains 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 selected from the group consisting of an alkylene group, an arylene group, a carbonyl group and an oxygen atom. . The alkylene group for L may be linear, branched or cyclic. When the alkylene group in L is linear or branched, the alkylene group preferably has 1 to 12 carbon atoms, more preferably 2 to 10 carbon atoms, and still more preferably 2 to 6 carbon atoms. .

  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 still 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 1,4-position, 1,2-position, and 1,3-position, and is preferably 1,2-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 1,4-position, 1,2-position, and 1,3-position, and is preferably the 1,2-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 hydroxy group, an amino group, a nitro group, and a phenyl group.

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

In general 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 shows the number of 0-10, m shows the number of 1-10.
The alkylene group for R ^{21 to} R ²⁴ may be linear, branched, or cyclic, and is preferably linear or branched, and more preferably linear.
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 1,4-position, 1,2-position, and 1,3-position, and is preferably the 1,2-position.

The alkylene group for R ²¹ and R ²² preferably has 2 to 10 carbon atoms, and more preferably 2 to 6 carbon atoms. The alkylene groups for 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, and 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, and an alkylene group having 2 to 6 carbon atoms from the viewpoint of antistatic properties and low contamination to an adherend. Is more preferable, and it is further more preferable that it is a C2-C6 linear or branched alkylene group.

  n represents the number of 0-10. When the first structural unit represented by the general formula (1) contained in the first (meth) acrylic copolymer is only one kind, n is an integer, and two or more kinds of the first structural unit are contained. In this case, n is a rational number that is an average value. n is preferably 0 to 4, and 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. More preferably a linear or branched alkylene group having 4 carbon atoms, a cyclic alkylene group having 5 to 6 carbon atoms, or a phenylene group, and a linear or branched alkylene group having 2 to 4 carbon atoms, More preferred is a cyclohexylene group or a phenylene group.

  m represents the number of 1-10. When the first structural unit represented by the general formula (1) contained in the first (meth) acrylic copolymer is only one type, m is an integer, and two or more first structural units are included. In this case, m is a rational number that is an average value. m is preferably 1 to 4, and more preferably 1 to 2.

The content of the first structural unit in the first (meth) acrylic copolymer is in the total mass of the first (meth) acrylic copolymer from the viewpoint of antistatic properties and low contamination to the adherend. It is preferably 0.5% by mass or more and 5% by mass or less, more preferably 0.5% by mass or more and 2% by mass or less, and further preferably 0.5% by mass or more and 1% by mass or less. .
When the content of the first structural unit is 0.5% by mass or more, the surface resistance of the pressure-sensitive adhesive composition tends to decrease, and more excellent antistatic properties tend to be obtained. Moreover, when the content rate of a 1st structural unit is 5 mass% or less, there exists a tendency which can suppress the viscosity raise over time of an adhesive composition and can obtain sufficient pot life.

  The first structural unit in the first (meth) acrylic copolymer includes, for example, a monomer represented by the following general formula (1a) and other constituents of the first (meth) acrylic copolymer. It can introduce | transduce into a 1st (meth) acryl copolymer by copolymerizing with a monomer.

In the general formula (1a), ^{R 1} and L are respectively the same as ^{R 1} and L in the general formula (1).

The monomer represented by the general formula (1a) may be produced by a conventional method or may be appropriately selected from commercially available monomers. Among the monomers represented by the general formula (1a), L is a monomer represented by the general formula (2a). (Meth) acrylic acid dimer (preferably an average of n in the general formula (2a) Ω-carboxy-polycaprolactone mono (meth) acrylate (preferably having an average value of n in the general formula (2a) of about 1.0). As these monomers, for example, those commercially available as "M-5600", "M-5300" (above, Toagosei Co., Ltd., trade name) can be used.
In addition, among the monomers represented by the general formula (1a), L represents a monomer represented by the general formula (2b), such as 2- (meth) acryloyloxyethyl succinic acid, 2- (meth) Examples include acryloyloxyethyl fumaric acid, 2- (meth) acryloyloxyethyl hexahydrophthalic acid, and 2- (meth) acryloyloxyethyl phthalic acid. These monomers include, for example, “light ester HO-MS”, “light acrylate HOA-MS (N)”, light acrylate HOA-HH (N), “light acrylate HOA-MPL (N)” (Kyoeisha) (Commercial name, product name) etc. can be used.

  The first (meth) acrylic copolymer contains at least one second structural unit derived from a monomer having a hydroxy group. The monomer having a hydroxy group forming the second structural unit is particularly a monomer having at least one hydroxy group and a polymerizable group capable of forming a copolymer with the first structural unit. It is not restrict | limited, It can select suitably from the monomer used normally and can be used.

  There is no restriction | limiting in particular in the method of introduce | transducing the 2nd structural unit derived from the monomer which has a hydroxyl group into a 1st (meth) acryl copolymer. For example, at least one monomer having a hydroxy group, at least one monomer represented by the general formula (1a), and other monomers (preferably alkyl (meta) ) Derived from a monomer having a first structural unit represented by the general formula (1) and a hydroxy group in the molecule by copolymerizing a monomer composition containing at least one kind of acrylate) A first (meth) acrylic copolymer containing the second structural unit can be obtained.

  Examples of the monomer having a hydroxy group include a monomer having a hydroxy group and an ethylenically unsaturated bond group. Specific examples of the monomer having a hydroxy group include 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 3-hydroxypropyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, 3 -Methyl-3-hydroxybutyl (meth) acrylate, 1,1-dimethyl-3-butyl (meth) acrylate, 1,3-dimethyl-3-hydroxybutyl (meth) acrylate, 2,2,4-trimethyl-3 -Hydroxypentyl (meth) acrylate, 2-ethyl-3-hydroxyhexyl (meth) acrylate, glycerin mono (meth) acrylate, polypropylene glycol mono (meth) acrylate, polyethylene glycol mono (meth) acrylate, poly (ethylene glycol-propyl) (Meth) acrylates such as pyrene glycol) mono (meth) acrylate; (meth) acrylamides such as N-methylol (meth) acrylamide and N-hydroxyethyl (meth) acrylamide; unsaturated such as allyl alcohol and methallyl alcohol Alcohol; and the like.

  Among them, from the point that compatibility and copolymerization with other monomers are good, and a crosslinking reaction with a crosslinking agent is good, one hydroxy group and an alkyl group having 2 to 6 carbon atoms are used. It is preferably a (meth) acrylic acid ester, and more preferably 2-hydroxyethyl (meth) acrylate or 4-hydroxybutyl (meth) acrylate.

  In the first (meth) acrylic copolymer, the content of the second structural unit derived from the monomer having a hydroxy group, the total mass of the first (meth) acrylic copolymer, It is preferably 0.1% by mass or more and 10.0% by mass or less, more preferably 2.0% by mass or more and 8.0% by mass or less, and 2.0% by mass or more and 5.0% by mass or less. More preferably it is. There exists a tendency which can suppress more effectively generation | occurrence | production of the contamination to a to-be-adhered body because the content rate of the structural unit derived from the monomer which has a hydroxyl group is more than the said lower limit. Moreover, there exists a tendency for a conformability (wetting property) to become more favorable because it is below the said upper limit.

  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 properties and low contamination to the adherend, the content ratio of the first structural unit to the second structural unit (first structural unit / second structural unit) is 1/10 on a mass basis. It is preferably ˜2 / 1, more preferably 1/5 to 4/3.

  The total content 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 properties and low contamination to the adherend, the total content of the first structural unit and the second structural unit is preferably 1% by mass or more and 15% by mass or less, and preferably 2% by mass or more. It is more preferably 10% by mass or less, and further preferably 3% by mass or more and 8% by mass or less.

The first (meth) acrylic copolymer preferably further includes at least one third structural unit derived from alkyl (meth) acrylate in addition to the first structural unit and the second structural unit. .
The alkyl group in the alkyl (meth) acrylate may be linear or branched. Moreover, it is preferable that it is 1-18 from the viewpoint of adhesiveness, and, as for carbon number of the alkyl group in alkyl (meth) acrylate, it is more preferable that it is 2-10.

  Specific examples of the alkyl (meth) acrylate include methyl (meth) acrylate, ethyl (meth) acrylate, n-butyl (meth) acrylate, isobutyl (meth) acrylate, n-octyl (meth) acrylate, and isooctyl (meth) acrylate. , 2-ethylhexyl (meth) acrylate, n-nonyl (meth) acrylate, isononyl (meth) acrylate, n-decyl (meth) acrylate, n-dodecyl (meth) acrylate, stearyl (meth) acrylate, etc. Mention may be made of alkyl (meth) acrylates having 18 straight-chain or branched alkyls and their derivatives.

  The first (meth) acrylic copolymer may contain one or more third structural units derived from alkyl (meth) acrylate, and preferably contains two or more kinds. When the first (meth) acrylic copolymer contains two types of third structural units, one is derived from an alkyl (meth) acrylate having a linear or branched alkyl group having 1 to 5 carbon atoms. It is a structural unit, and the other is preferably a structural unit derived from an alkyl (meth) acrylate having a linear or branched alkyl group having 6 to 18 carbon atoms, one having 2 to 5 carbon atoms. A structural unit derived from an alkyl (meth) acrylate having a linear alkyl group, the other being a structural unit derived from an alkyl (meth) acrylate having a branched alkyl group having 6 to 10 carbon atoms It is more preferable.

  When the first (meth) acrylic copolymer includes the third structural unit, the content of the third structural unit is 60% by mass in the total mass of the first (meth) acrylic copolymer. The content is preferably 99.9% by mass or less, more preferably 72% by mass or more and 99.5% by mass or less, and still more preferably 85% by mass or more and 99% by mass or less. When the content of the third structural unit is equal to or higher than the lower limit value, the conformability (wetting property) tends to be better. Further, when the content of the third structural unit is not more than the above upper limit value, the adhesive force at the time of high-speed peeling does not become too large, and the workability at the time of high-speed peeling tends to be excellent.

  The 1st (meth) acrylic copolymer may further contain other structural units other than the 1st structural unit, the 2nd structural unit, and the 3rd structural unit as needed. Other monomers forming the structural unit include (meth) acrylates having a cyclic group such as cyclohexyl (meth) acrylate and benzyl (meth) acrylate; saturated fatty acid vinyl esters such as vinyl formate, vinyl acetate, propionic acid Aliphatic vinyl monomers such as vinyl and “vinyl versatate” (trade name, vinyl neodecanoate); aromatic vinyl monomers such as styrene, α-methylstyrene and vinyltoluene; cyanovinyl such as acrylonitrile and methacrylonitrile Monomer: Dimethyl malate, di-n-butyl malate, di-2-ethylhexyl malate, di-n-octyl malate, dimethyl fumarate, di-n-butyl fumarate, di-2-ethylhexyl fumarate, Maleic acid or fumaric acid such as di-n-octyl fumarate Diester monomers; and the like.

  Further, the monomer that forms other structural unit is a monomer having at least one functional group in addition to one radical polymerizable group in the molecule, and forms the first structural unit. A monomer different from the monomer and the monomer forming the second structural unit (hereinafter also referred to as “functional monomer”) can be exemplified. As the functional monomer, a monomer having a functional group such as a carboxy 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. The body can be mentioned. A monomer having two or more radically polymerizable groups in the molecule can also be used.

  Specific examples of these functional monomers include, for example, carboxy groups such as (meth) acrylic acid, itaconic acid, maleic anhydride, or anhydride group-containing monomers; (meth) acrylamide, diacetone acrylamide, N -Substitution or no substitution of methylol (meth) acrylamide, Nn-butoxymethyl (meth) acrylamide, N-isobutoxymethyl (meth) acrylamide, N, N-dimethyl (meth) acrylamide, N-methyl (meth) acrylamide, etc. Substituted amide group-containing monomer; substituted or unsubstituted amino group-containing monomer such as aminoethyl (meth) acrylate, N, N-dimethylaminoethyl (meth) acrylate, N, N-diethylaminoethyl (meth) acrylate Body; 2-methoxyethyl (meth) acrylate, 2-ethoxyethyl (Meth) acrylate, 2-n-butoxyethyl (meth) acrylate, 2-methoxyethoxyethyl (meth) acrylate, 2-ethoxyethoxyethyl (meth) acrylate, 2-n-butoxyethoxyethyl (meth) acrylate, methoxypolyethylene Alkoxy group-containing monomers such as glycol mono (meth) acrylate and methoxypolyethylene glycol monomethacrylate; Epoxy group-containing monomers such as glycidyl (meth) acrylate, glycidyl allyl ether and glycidyl methallyl ether; Mercapto groups such as allyl mercaptan Monomer: Vinyltrichlorosilane, vinyltribromosilane, vinyltrimethoxysilane, vinyltriethoxysilane, vinyltri-n-propoxysilane, vinyltriisopropoxysila , Vinyltri-n-butoxysilane, vinyltris (2-methoxyethoxy) silane, vinyltris (2-hydroxymethoxyethoxy) silane, vinyltriacetoxysilane, vinyldiethoxysilanol, vinylethoxysiladiol, vinylmethyldiethoxysilane, vinyldimethyl Ethoxysilane, vinylmethyldiacetoxysilane, allyltrimethoxysilane, allyltriethoxysilane, 3- (meth) acryloxypropyltrimethoxysilane, 3- (meth) acryloxypropyltriethoxysilane, 3- (meth) acryloxy Propyltris (2-methoxyethoxy) silane, 3- (meth) acryloxypropylmethyldiethoxysilane, 3- (meth) acryloxypropyldimethylethoxysilane, 3- (meth) acrylo A monomer group such as a monomer having a silicon-containing group such as xylpropyldimethylmethoxysilane and 2- (meth) acrylamidoethyltriethoxysilane;

  When the first (meth) acrylic copolymer includes other structural units, the content of the other structural units is 30% by mass or less in the total mass of the first (meth) acrylic copolymer. Preferably, it is 20 mass% or less, more preferably 10 mass% or less. There exists a tendency which can make the adhesive force balance of low speed peeling and high speed peeling more favorable as the content rate of another structural unit is below the said upper limit.

  Furthermore, when the first (meth) acrylic copolymer includes a structural unit derived from a monomer having a carboxy group which is a functional monomer as another structural unit, the monomer having the carboxy group The content of the structural unit derived from is preferably 0.5% by mass or less and more preferably 0.2% by mass or less in the total mass of the first (meth) acrylic copolymer. Preferably, it is not included. When the content of the structural unit derived from the monomer having a carboxy group is not more than the above upper limit value, the antistatic performance tends to be improved.

  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, and more preferably 300,000 or more and 800,000 or less. If the weight average molecular weight (Mw) of a 1st (meth) acryl copolymer is more than the said lower limit, there exists a tendency which can suppress generation | occurrence | production of the contamination to a to-be-adhered body more effectively. Moreover, if it is below the said upper limit, there exists a tendency for a conformability (wetting property) to become more favorable.

  The dispersity (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, and 15 or less. More preferably, it is more preferably in the range of 3-10. If the value of the degree of dispersion (Mw / Mn) is less than or equal to the upper limit value, the occurrence of contamination on the adherend tends to be more effectively suppressed.

  In addition, the weight average molecular weight (Mw) and number average molecular weight (Mn) of a 1st (meth) acryl copolymer are the values measured by the following method.

Method for measuring average molecular weight (Mw and Mn):
It measures according to following (1)-(3).
(1) A solution of a (meth) acrylic copolymer is applied to release paper and dried at 100 ° C. for 2 minutes to obtain a film-like (meth) acrylic copolymer.
(2) Using the film-like (meth) acrylic copolymer obtained in (1) above and tetrahydrofuran, a sample solution having a solid content concentration of 0.2% by mass is obtained.
(3) The weight average molecular weight (Mw) and number average molecular weight (Mn) of the (meth) acrylic copolymer are measured as standard polystyrene conversion values using gel permeation chromatography (GPC) under the following conditions. .

(conditions)
GPC: HLC-8220 GPC [manufactured by Tosoh Corporation]
Column: 4 TSK-GEL GMHXL used Mobile phase solvent: Tetrahydrofuran Flow rate: 0.6 mL / min Column temperature: 40 ° C

The content rate of the 1st (meth) acrylic copolymer in an adhesive composition can be suitably selected according to the objective etc. The content of the first (meth) acrylic copolymer is preferably 80% by mass or more and 99% by mass or less, and 85% by mass or more and 99% by mass or less in the total solid content of the pressure-sensitive adhesive composition. More preferably, it is 90 mass% or more and 98 mass% or less.
In addition, solid content gross mass means the gross mass of the residue remove | excluding volatile components, such as a solvent, from an adhesive composition.

(Second (meth) acrylic copolymer)
The pressure-sensitive adhesive composition comprises a second (meth) acrylic copolymer (hereinafter referred to as “resin B”) containing a structural unit having a polyalkyleneoxy group and having a lower molecular weight than the first (meth) acrylic copolymer. It is preferable to further contain at least one of (also referred to as). When the pressure-sensitive adhesive composition contains the second (meth) acrylic copolymer in addition to the first (meth) acrylic copolymer, more excellent antistatic properties can be achieved.

  The second (meth) acrylic copolymer contains a structural unit having a polyalkyleneoxy group and has a molecular weight smaller than that of the first (meth) acrylic copolymer, so that it is relatively easy in the pressure-sensitive adhesive composition. It is thought that it can move. Thereby, it is thought that the surface resistance value of an adhesive composition falls more effectively and can achieve the more superior antistatic property.

The second (meth) acrylic copolymer includes at least one 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 structural unit, and an alkyleneoxy group having 2 to 3 carbon atoms as a structural unit. It is more preferable that it is included.
The number of alkyleneoxy groups contained in the polyalkyleneoxy group can be appropriately selected according to the purpose and the like. From the viewpoint of antistatic properties, the content of the alkyleneoxy group is preferably 20 or more, more preferably 20 to 100, still more preferably 20 to 50. When the content of the alkyleneoxy group is 20 or more, a more remarkable antistatic effect can be exhibited by a combination with an alkali metal salt described later. In addition, when the 2nd (meth) acryl copolymer contains 2 or more types of structural units having an alkyleneoxy group, the content of the alkyleneoxy group is a rational number that is an average value of the content.

  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 part of the polyalkyleneoxy group is an alkoxy group, the alkoxy group preferably has 1 to 10 carbon atoms, and more preferably 1 to 5 carbon atoms.

  The structural unit having a polyalkyleneoxy group may be derived from a monomer having a polyalkyleneoxy group and a polymerizable group, but the structural unit having no polyalkyleneoxy group may be converted into a polyalkyleneoxy group by a polymer reaction. A group may be introduced. From the viewpoint of productivity, the structural 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 (meth) acrylate, methoxypolypropyleneoxy ( A meth) acrylate, an ethoxy polypropyleneoxy (meth) acrylate, etc. can be mentioned. Among these, methoxypolyethyleneoxy (meth) acrylate and methoxypolypropyleneoxy (meth) acrylate are preferably at least one selected from the group consisting of methoxypolyethyleneoxy (meth) acrylate, methoxypolyethyleneoxy (meth) acrylate having an ethyleneoxy group content of 20 or more, and More preferably, it is at least one selected from the group consisting of methoxypolypropyloxyoxy (meth) acrylates having a propyleneoxy group content of 20 or more.

  The 2nd (meth) acrylic copolymer may contain the structural unit which has a polyalkyleneoxy group individually by 1 type or in combination of 2 or more types.

  The content of the structural unit having a polyalkyleneoxy group in the second (meth) acrylic copolymer is 1 mass in the total mass of the second (meth) acrylic copolymer from the viewpoint of antistatic properties. % To 50% by mass, preferably 1% to 30% by mass, and more preferably 5% to 20% by mass.

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. Moreover, it is preferable that it is 1-18 from the viewpoint of antistatic property, and, as for carbon number of the alkyl group in alkyl (meth) acrylate, it is more preferable that it is 2-10.

Specific examples of the alkyl (meth) acrylate include methyl (meth) acrylate, ethyl (meth) acrylate, n-butyl (meth) acrylate, isobutyl (meth) acrylate, n-octyl (meth) acrylate, and isooctyl (meth) acrylate. , 2-ethylhexyl (meth) acrylate, n-nonyl (meth) acrylate, isononyl (meth) acrylate, n-decyl (meth) acrylate, n-dodecyl (meth) acrylate, stearyl (meth) acrylate, etc. Mention may be made of alkyl (meth) acrylates having 18 straight-chain or branched alkyls and their derivatives.
The second (meth) acrylic copolymer may contain one or more structural units derived from alkyl (meth) acrylate.

  When the second (meth) acrylic copolymer contains a structural unit derived from alkyl (meth) acrylate, the content of the structural unit derived from alkyl (meth) acrylate is the second (meth) acrylic copolymer The total mass of the coalescence is preferably 40% by mass or more and 95% by mass or less, more preferably 70% by mass or more and 90% by mass or less, and further preferably 80% by mass or more and 90% by mass or less. . There exists a tendency which can suppress generation | occurrence | production of the contamination to a to-be-adhered body more effectively as the content rate of the structural unit derived from an alkyl (meth) acrylate is more than the said lower limit. Moreover, if the content rate of the structural unit derived from alkyl (meth) acrylate is below the said upper limit, the surface resistance of an adhesive composition will fall and there exists a tendency which can obtain the more superior antistatic property. .

  The second (meth) acrylic copolymer may contain other structural units other than the structural unit having a polyalkyleneoxy group and the structural unit derived from an alkyl (meth) acrylate, if necessary. Examples of other structural units include the same structural units as those in the first (meth) alkyl copolymer, and preferred embodiments are also the same.

  The molecular weight of the second (meth) acrylic copolymer is not particularly limited as long as it 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, More preferably, it is 000 or more and 20,000 or less. There exists a tendency which can suppress generation | occurrence | production of the contamination to a to-be-adhered body more effectively as the weight average molecular weight (Mw) of a 1st (meth) acryl copolymer is more than the said lower limit. Moreover, there exists a tendency for antistatic property to improve that it is below the said upper limit.

  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. Preferably, it is in the range of 1-5. If the value of Mw / Mn is less than or equal to the upper limit, there is a tendency that the occurrence of contamination on the adherend tends to be more effectively suppressed. The weight average molecular weight (Mw) and the number average molecular weight (Mn) of the second (meth) acrylic copolymer are measured by the same method as that for the first (meth) acrylic copolymer.

  The ratio (second / first) of the weight average molecular weight of the second (meth) acrylic copolymer to the first (meth) acrylic copolymer is not particularly limited as long as it is less than 1. From the viewpoint of antistatic properties, the ratio of the weight average molecular weight is preferably 0.1 or less, and more preferably 0.006 to 0.07.

  The content rate of the 2nd (meth) acrylic copolymer in an adhesive composition can be suitably selected according to the objective etc. 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 with respect to 100 parts by mass of the first (meth) acrylic copolymer, It is more preferably 0.1 parts by mass or more and 1.5 parts by mass or less, and further preferably 0.2 parts by mass or more and 1.0 parts by mass or less. If the content of the second (meth) acrylic copolymer is 0.05 parts by mass or more with respect to 100 parts by mass of the first (meth) acrylic copolymer, a more excellent antistatic effect can be obtained. Tend. If the content of the second (meth) acrylic copolymer is 2.0 parts by mass or less with respect to 100 parts by mass of the first (meth) acrylic copolymer, the contamination of the adherend is more effective. Tend to be suppressed.

  The first (meth) acrylic copolymer and the second (meth) acrylic copolymer (hereinafter may be collectively referred to as “copolymer”) are structural units contained in these copolymers. It can be produced by polymerizing a mixture of monomers capable of forming. The polymerization method of the copolymer is not particularly limited, and can be appropriately selected from known methods such as a solution polymerization method, an emulsion polymerization method, and a suspension polymerization method. When the pressure-sensitive adhesive composition of the present invention is produced using the copolymer obtained by polymerization, it is preferably polymerized by a solution polymerization method because the treatment process is relatively simple and can be performed in a short time.

  In the solution polymerization method, generally, a predetermined organic solvent, a monomer, a polymerization initiator, and a chain transfer agent used as necessary are charged in a polymerization tank, and stirred in a nitrogen stream at the reflux temperature of the organic solvent. However, it is possible to use a known method such as heating for several hours.

  In addition, the weight average molecular weight and dispersion degree of the first (meth) acrylic copolymer and the second (meth) acrylic copolymer are easily adjusted by the reaction temperature, time, solvent amount, type and amount of the catalyst. be able to.

  As an organic solvent for polymerization used for polymerization of the first (meth) acrylic copolymer and the second (meth) acrylic copolymer, benzene, toluene, ethylbenzene, n-propylbenzene, t-butylbenzene, aromatic hydrocarbons such as o-xylene, m-xylene, p-xylene, tetralin, decalin, aromatic naphtha; n-hexane, n-heptane, n-octane, isooctane, n-decane, dipentene, petroleum spirit, Aliphatic or alicyclic hydrocarbons such as petroleum naphtha and turpentine oil; ethyl acetate, n-butyl acetate, n-amyl acetate, 2-hydroxyethyl acetate, 2-butoxyethyl acetate, 3-methoxybutyl acetate, benzoic acid Esters such as methyl acid; acetone, methyl ethyl ketone, methyl isobutyl ketone, isophorone, cyclohexa Ketones such as ethylene 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, diethylene glycol monobutyl ether; methyl alcohol, ethyl alcohol, n -Alcohols such as propyl alcohol, isopropyl alcohol, n-butyl alcohol, isobutyl alcohol, s-butyl alcohol, t-butyl alcohol; These organic solvents can be used alone or in combination of two or more.

  As said polymerization initiator, it is possible to use the organic peroxide, an azo compound, etc. which can be used by a normal solution polymerization method. Examples of the organic peroxide include t-butyl hydroperoxide, cumene hydroxide, dicumyl peroxide, benzoyl peroxide, lauroyl peroxide, caproyl peroxide, diisopropyl peroxydicarbonate, di-2-ethylhexyl peroxide. Oxydicarbonate, t-butylperoxybivalate, 2,2-bis (4,4-di-t-butylperoxycyclohexyl) propane, 2,2-bis (4,4-di-t-amylperoxy) Cyclohexyl) propane, 2,2-bis (4,4-di-t-octylperoxycyclohexyl) propane, 2,2-bis (4,4-di-α-cumylperoxycyclohexyl) propane, 2,2- Bis (4,4-di-t-butylperoxycyclohexyl) butane, , 2-bis (4,4-di -t- octylperoxycarbonyl cyclohexyl) butane. Examples of the azo compound include 2,2′-azobisisobutyronitrile, 2,2′-azobis-2,4-dimethylvaleronitrile, 2,2′-azobis-4-methoxy-2,4-dimethyl. Examples include valeronitrile.

  Further, in the production of the first (meth) acrylic copolymer and the second (meth) acrylic copolymer, it is normal not to use a chain transfer agent, but this does not impair the purpose and effect of the present invention. In range, it is possible to use as needed. Examples of the chain transfer agent include cyanoacetic acid; alkyl esters having 1 to 8 carbon atoms of cyanoacetic acid; bromoacetic acid; alkyl esters having 1 to 8 carbon atoms of bromoacetic acid; anthracene, phenanthrene, fluorene, 9-phenylfluorene. Aromatic compounds such as p-nitroaniline, nitrobenzene, dinitrobenzene, p-nitrobenzoic acid, p-nitrophenol, p-nitrotoluene, etc .; benzoquinone, 2,3,5,6-tetra Benzoquinone derivatives such as methyl-p-benzoquinone; borane derivatives such as tributylborane; carbon tetrabromide, carbon tetrachloride, 1,1,2,2-tetrabromoethane, tribromoethylene, trichloroethylene, bromotrichloromethane, tri Halogens such as bromomethane and 3-chloro-1-propene Hydrocarbons; Aldehydes such as chloral and furaldehyde: alkyl mercaptans having 1 to 18 carbon atoms; aromatic mercaptans such as thiophenol and toluene mercaptan; alkyl esters having 1 to 10 carbon atoms of mercaptoacetic acid and mercaptoacetic acid; Examples thereof include hydroxyalkyl mercaptans having 1 to 12 carbon atoms; terpenes such as pinene and terpinolene;

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

  When producing the first (meth) acrylic copolymer and the second (meth) acrylic copolymer, a purification step for purifying the polymer obtained by the polymerization reaction may be provided. Thereby, when an unreacted monomer is contained in a polymer obtained by a solution polymerization method or the like, the monomer can be removed. The purification step can be appropriately selected from commonly used purification methods. For example, it can be purified by reprecipitation with methanol or the like.

[Polyether-modified silicone]
The pressure-sensitive adhesive composition contains at least one polyether-modified silicone having a hydroxy group at the polyether terminal (hereinafter also referred to as “specific polysiloxane compound”). When the polyether-modified silicone has a hydroxy group at the polyether terminal, it exhibits excellent antistatic properties and can effectively suppress contamination on the adherend.

  Since the specific polysiloxane compound has a polyalkyleneoxy group whose terminal is a hydroxy group in the molecule, the antistatic performance is effectively exhibited. This is because, for example, the specific polysiloxane compound is unevenly distributed near 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 near the surface of the pressure-sensitive adhesive layer. As a result, it can be considered to reduce the surface resistance value on the surface of the pressure-sensitive adhesive layer.

  In general, if the pressure-sensitive adhesive composition contains a polyether-modified silicone having a hydroxy group at the polyether terminal as a polysiloxane compound, the effect of reducing the surface resistance value 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 is sufficiently increased by containing the first (meth) acrylic copolymer containing the first structural unit represented by the general formula (1). Can be reduced. On the other hand, in the (meth) acrylic copolymer containing a structural unit having a carboxy group derived from (meth) acrylic acid or the like, it is difficult to sufficiently reduce the surface resistance value of the pressure-sensitive adhesive composition. Furthermore, the surface resistance value of an adhesive composition can be reduced more effectively by including the 2nd structural unit which a 1st (meth) acryl copolymer originates in the monomer which has a hydroxyl group. it is conceivable that.

The specific polysiloxane compound is a polysiloxane compound containing a structural unit derived from dialkylsiloxane and a structural unit derived from alkyl (hydroxypolyalkyleneoxyalkyl) siloxane from the viewpoint of antistatic properties and low contamination to the adherend. Preferably there is.
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, and more preferably 2 to 3 carbon atoms. The content of alkyleneoxy groups in the alkyl (hydroxypolyalkyleneoxyalkyl) siloxane is preferably 1 to 100, and 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 dialkylsiloxane and a structural unit derived from alkyl (hydroxypolyalkyleneoxyalkyl) siloxane, the number of structural units derived from dialkylsiloxane may be 100 or less. Preferably, it is 1-80. The number of structural units derived from alkyl (hydroxypolyalkyleneoxyalkyl) siloxane is preferably 2 to 100, and 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 properties and low contamination to the adherend.

  In general formula (3), p is the repeating number of a dimethylsiloxane structural unit, and represents the number of 0-100. q is the number of repeating methylpropylenesiloxane structural units having a polyoxyethylene group and represents a number of 2 to 100. A is the number of repeating ethyleneoxy structural units and represents a 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 average values as the aggregate of the compounds and are rational numbers.

  The repeating number a of the polyethyleneoxy structural unit is a number of 1 to 100, but is preferably a number of 10 to 100. When a is 1 or more, sufficient conductivity is obtained and the antistatic effect tends to be improved. Moreover, when a is 100 or less, the 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.

Moreover, the repeating number p of a dimethylsiloxane structural unit is a number of 0-100, but it is preferable that it is a number of 1-80. When p is 0 or more, the antistatic effect tends to be improved. Further, 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.
Further, the repeating number q of the methylpropylenesiloxane structural unit is 2 to 100, but preferably 2 to 80. When q is 2 or more, sufficient conductivity is obtained, and the antistatic effect tends to be improved. Moreover, when q is 100 or less, the 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.

  There is no restriction | limiting in particular about the weight average molecular weight of a specific polysiloxane compound, For example, it can be 5,000 or more and 20,000 or less, and it is preferable that it is 6,000 or more and 15,000 or less.

Further, the HLB value of the specific polysiloxane compound is not particularly limited, but is preferably 5 or more and less than 16, and preferably 7 or more and 15 or less from the viewpoint of compatibility with the resin, surface unevenness, and adhesiveness. More preferred.
The HLB value is a scale indicating the balance between hydrophilicity and hydrophobicity of a specific polysiloxane compound (surfactant). In the present invention, the definition of the Griffin method calculated by the following formula 1 is followed. However, when the specific polysiloxane compound is a commercial product, the catalog data is preferentially adopted.
Formula 1 {(sum of formula weight of hydrophilic group part) / (molecular weight of surfactant)} × 20

  The specific polysiloxane compound has a dimethylsiloxane structural unit and a methylpropylenesiloxane structural unit having a polyoxyethylene group in the molecule. These structural units may constitute a block copolymer or a random copolymer, respectively.

  Specific examples of the specific polysiloxane compound represented by the general formula (3) include, for example, “SF-8428”, “FZ-2162”, “SH-3773M” [above, manufactured by Toray Dow Co., Ltd. And the like.

  Even if the specific polysiloxane compound is selected from the above-mentioned commercial products, an organic compound having an unsaturated bond and a polyoxyethylene group is added to the dimethylpolysiloxane main chain having silicon hydride. It can also be obtained by grafting through 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 with respect to 100 parts by mass of the first (meth) acrylic copolymer. 0.05 parts by mass or more and 0.4 parts by mass or less is more preferable, and 0.05 parts by mass or more and 0.3 parts by mass or less are more preferable.

  The antistatic effect at the time of peeling a surface protective film can be more effectively acquired because specific polysiloxane compound content is more than the said lower limit. In addition, when the content of the specific polysiloxane compound is less than or equal to the above upper limit, the occurrence of contamination (spider) to the adherend is suppressed, and the compatibility with the acrylic copolymer is reduced, resulting in white turbidity. Can be suppressed.

In addition to the polysiloxane compound represented by the general formula (3), the pressure-sensitive adhesive composition has a structure different from the general formula (3) as long as the effects of the present invention are not impaired. A dimethylpolysiloxane compound may be included.
Examples of the dimethylpolysiloxane compound having a structure different from that of the general formula (3) and having a polyethyleneoxy group include compounds in which the end of the polyethyleneoxy group is an alkoxy group, an acyloxy group, or the like, and a polyoxyethylene group is a side chain. Instead, compounds included in the main chain or the terminal can be exemplified.

  Specifically, for example, “BY-16-201”, “FZ-77”, “FZ-2104”, “FZ-2110”, “FZ-2203”, “FZ-2207”, “FZ-2208”, “L-7001”, “L-7002”, “SF-8427”, “SH-3749”, “SH-8400” [above, manufactured by Toray Dow Co., Ltd.] and the like can be mentioned.

  When the pressure-sensitive adhesive composition contains a dimethylpolysiloxane compound having a structure different from that of the general formula (3) and containing a polyethyleneoxy group, the content is 0.05 in the total mass of the polysiloxane compound. It is preferably at most mass%, more preferably at most 0.03% by mass.

[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 a cation of lithium ion (Li ⁺ ), sodium ion (Na ⁺ ), potassium ion (K ⁺ ), rubidium (Rb ⁺ ), or the like.
Specifically, cations such as Li ⁺ , Na ⁺ , K ⁺ , Cl ⁻ , Br ⁻ , I ⁻ , BF ₄ ⁻ , PF ₆ ⁻ , SCN ⁻ , ClO ₄ ⁻ , CF ₃ SO ₃ ⁻ , (CF ^{_{3 sO 2) 2 N -,}} (C 2 F 5 sO 2) 2 N -, (CF 3 sO 2) 3 C - metal salt composed of anions or the like is preferably used.

Among them, alkali metal salts are 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 ) from the viewpoint of antistatic. ) Lithium salts such as ₂ N and Li (CF ₃ SO ₂ ) ₃ C are preferably used.
In particular, alkali metal salts are 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 ) from the viewpoint of antistatic effect and metal corrosiveness. ) A lithium salt containing a fluoromethylsulfonyl group such as ₃ C is preferred, and at least one selected from the group consisting of LiCF ₃ SO ₃ , Li (CF ₃ SO ₂ ) ₂ N and Li (C ₂ F ₅ SO ₂ ) ₂ N Species are more preferred.
These alkali metal salts may be used individually by 1 type, and 2 or more types may be mixed and used for them.

The content of the alkali metal salt in the pressure-sensitive adhesive composition is preferably 0.005 parts by mass or more and 0.6 parts by mass or less with respect to 100 parts by mass of the first (meth) acrylic copolymer. It is more preferably 005 parts by mass or more and 0.3 parts by mass or less, and further preferably 0.01 parts by mass or more and 0.2 parts by mass or less.
When the content of the alkali metal salt is 0.005 parts by mass or more with respect to 100 parts by mass of the first (meth) acrylic copolymer, sufficient charging characteristics can be obtained. On the other hand, when the content of the alkali metal salt is 0.6 parts by mass or less, the antistatic effect rate with respect to the content can be sufficiently obtained.

  The mass ratio of the specific polysiloxane compound to the alkali metal salt (specific polysiloxane compound / alkali metal salt) in the pressure-sensitive adhesive composition is from 0.1 to 5 from the viewpoint of antistatic effect and adhesiveness. Is preferable, and it is more preferable that it is 0.5 or more and 4 or less.

  The total content of the specific polysiloxane compound and the alkali metal salt in the pressure-sensitive adhesive composition is 0.10 parts by mass or more and 1.00 parts by mass or less with respect to 100 parts by mass of the first (meth) acrylic copolymer. It is preferable that it is 0.10 parts by mass or more and 0.50 parts by mass or less.

[Polyisocyanate compound]
The pressure-sensitive adhesive composition preferably further contains at least one polyisocyanate compound in addition to the essential components. The polyisocyanate compound, the first (meth) acrylic copolymer, and the specific polysiloxane compound are each subjected to a crosslinking reaction, whereby the adhesiveness and the low contamination to the adherend are improved in a well-balanced manner.

Examples of the polyisocyanate compound include aromatic polyisocyanate compounds such as xylylene diisocyanate, diphenylmethane diisocyanate, triphenylmethane triisocyanate, and tolylene diisocyanate; for example, hexamethylene diisocyanate, isophorone diisocyanate, and hydrogen of the aromatic polyisocyanate compound. Examples thereof include aliphatic or alicyclic polyisocyanate compounds such as additives; dimers or trimers of these polyisocyanate compounds; adducts of these polyisocyanate compounds and polyol compounds such as trimethylolpropane. . Among these polyisocyanate compounds, it is preferably at least one selected from the group consisting of hexamethylene diisocyanate and hexamethylene diisocyanate dimer, trimer and adduct, and the hexamethylene diisocyanate trimer is Particularly preferred.
These polyisocyanate compounds can be used alone or in admixture of two or more.

  Examples of the polyisocyanate compound include “Coronate HX”, “Coronate HL-S”, “Coronate 2234”, “Aquanate 200”, “Aquanate 210” (manufactured by Nippon Polyurethane Co., Ltd.), “Desmodur N3300”. "Death Module N3400" (manufactured by Sumitomo Bayer Urethane Co., Ltd.), "Duranate E-405-80T", "Duranate 24A-100", "Duranate TSE-100" (manufactured by Asahi Kasei Corporation), " Commercially available products such as “Takenate D-110N”, “Takenate D-120N”, “Takenate M-631N”, “MT-Olestar NP1200” (manufactured by Mitsui Takeda Chemical Co., Ltd.) can do.

The content of these polyisocyanate compounds is preferably 0.1 parts by mass or more and 10 parts by mass or less, and 0.5 parts by mass or more and 5 parts by mass or less with respect to 100 parts by mass of the first (meth) acrylic copolymer. It is more preferable that the amount is not more than part by mass.
Further, if necessary, a curing catalyst such as dibutyltin laurate may be further added.

  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 include a weather resistance stabilizer, a tackifier, a plasticizer, and a softener as necessary. , Peeling aids, dyes, pigments, inorganic fillers, surfactants, and the like can be appropriately contained.

<Optical member surface protective film>
The optical member surface protective film of the present invention includes a polyester base material and a pressure-sensitive adhesive layer derived from the pressure-sensitive adhesive composition while being provided on the polyester base material.
By forming the pressure-sensitive adhesive layer from the pressure-sensitive adhesive composition, a pressure-sensitive adhesive layer that is excellent in all of adhesion, suppression of generation of static electricity due to peeling electrification, and low contamination to the adherend is formed. Can do.

The base material used for 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.
From the viewpoint of inspection and management of optical members by fluoroscopy, the base material is polyester resin, acetate resin, polyethersulfone resin, polycarbonate resin, polyamide resin, polyimide resin, polyolefin resin, acrylic resin. The film which consists of resin etc. can be mentioned. Among these, from the viewpoint of surface protection performance, a polyester resin is preferable, and a polyethylene terephthalate resin is particularly preferable in consideration of practicality.

  Generally the thickness of the said base material can be 500 micrometers or less, Preferably it is 5 micrometers-300 micrometers, More preferably, the thickness of about 10 micrometers-200 micrometers can be illustrated.

  An antistatic layer may be provided on one side or both sides of the base material for the purpose of preventing charging during peeling. Moreover, in order to improve the adhesiveness with an adhesive layer, the corona discharge process etc. may be given to the surface by which the adhesive layer is provided of the said base material.

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, for example, a pressure-sensitive adhesive composition containing a polyisocyanate compound is used as it is or necessary. Accordingly, it is possible to employ a method of diluting with an appropriate solvent, applying this directly to the surface protective base film (base material), and drying to remove the solvent.
Further, first, for example, a pressure-sensitive adhesive composition containing a polyisocyanate compound is applied on a release sheet made of an appropriate film such as paper or polyester film which has been subjected to a release treatment with a silicone resin, and then dried by heating and adhered. It is also possible to adopt a method in which an adhesive layer is formed, and then the pressure-sensitive adhesive layer side of the release sheet is pressed against a surface protective base film (base material) to transfer the pressure-sensitive adhesive layer to the protective film.

In the present invention, the pressure-sensitive adhesive layer is preferably a pressure-sensitive adhesive layer obtained by crosslinking the first (meth) acrylic copolymer and the specific polysiloxane compound with a polyisocyanate compound contained in the pressure-sensitive adhesive composition. Thereby, the adhesiveness of an adhesive layer and the low pollution property with respect to a to-be-adhered body improve more.
The conditions for crosslinking the first (meth) acrylic copolymer and the specific polysiloxane compound with the polyisocyanate compound are not particularly limited.

  For example, the pressure-sensitive adhesive layer has a sufficient adhesive force for large optical members such as those used for liquid crystal display screens of 20 inches or more (the adhesive force for low-speed peeling is sufficiently large) and easily at the time of high-speed peeling. It is preferable that it can be peeled (adhesive strength at high-speed peeling does not increase) and has good conformability (the cut end does not turn up when cut).

That is, the adhesive strength of 180 ° peel at 23 ° C. to the optical member is preferably 0.05 N / 25 mm or more at a peeling speed of 0.3 m / min (low speed peeling). More preferably, it is 06 N / 25 mm or more.
When the adhesive force at the time of low-speed peeling is 0.05 N / 25 mm or more, the occurrence of turning or deviation is suppressed.

  Moreover, since the workability at the time of high-speed peeling in a large area decreases as the adhesive strength increases, the adhesive strength (peeling force) at a peeling speed of 30 m / min (high-speed peeling) is preferably less than 1.5 N / 25 mm. More preferably, it is less than 1.2 N / 25 mm.

  Further, since the optical member may be damaged if the charge at the time of peeling is large, the pressure-sensitive adhesive composition of the present invention has an absolute value of the peeling band voltage at the time of peeling of 30 m / min with respect to the antiglare polarizing plate of 0.9 kV or less. Preferably, it is 0.4 kV or less, and more preferably 0.35 kV or less.

Further, from the viewpoint of preventing charging on the film side at the time of peeling, the surface resistance value of the pressure-sensitive adhesive layer is preferably less than 1.0E + 12 (Ω / □) (1.0 × 10 ¹² Ω / □). .

  The thickness of the pressure-sensitive adhesive layer formed on the substrate can be appropriately set according to the adhesive force required for the protective film, the surface roughness of the optical member, etc., and is generally 1 μm to 100 μm, preferably 5 μm to 50 μm, More preferably, a thickness of about 15 μm to 30 μm can be exemplified.

  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, and when the optical member is processed into a liquid crystal display plate or the like. Is applied to each process such as punching, inspection, transportation, and assembly of the liquid crystal display panel in a state where the protective film is laminated on the optical member, and if necessary, autoclave treatment, high temperature aging treatment, etc. It is peeled and removed from the optical member when it is subjected to heat and pressure treatment and surface protection is no longer necessary.

  EXAMPLES The present invention will be specifically described below with reference to examples, but the present invention is not limited to these examples. Unless otherwise specified, “part” and “%” are based on mass.

(Production Example 1)
-Production of first (meth) acrylic copolymer 1-
In a reactor equipped with a thermometer, a stirrer, a nitrogen introducing tube and a reflux condenser, 20 parts of ethyl acetate and 10 parts of toluene are placed, and in another container, 50 parts of butyl acrylate (BA), 2 -46 parts of ethylhexyl acrylate (2EHA), 3 parts of 4-hydroxybutyl acrylate (4HBA) as a monomer having a hydroxy group, Aronix M-5300 (M5300, Toagosei Co., Ltd.) as a monomer represented by the general formula (1a) (Made by Co., Ltd.) 1 part is mixed to form a monomer mixture, 25% of which is added to the reaction vessel, and then the air in the reaction vessel is replaced with nitrogen gas. 0.02 part of nitrile (hereinafter referred to as AIBN) was added, and the temperature of the mixture in the reaction vessel was raised to 70 ° C. in a nitrogen atmosphere with stirring to start the initial reaction. It was. After the initial reaction was almost completed, the remaining monomer mixture 75%, and a mixture of 20 parts of ethyl acetate, 10 parts of toluene and 0.2 part of AIBN were allowed to react for about 2 hours, followed by another 2 hours. Reacted. Thereafter, a solution in which 0.25 part of AIBN was dissolved in 25 parts of toluene was added dropwise over 1 hour, and the mixture was 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 obtained first (meth) acrylic copolymer had a weight average molecular weight (Mw) of 530,000 and a dispersity (Mw / Mn) of 8.2.

(Production Example 2)
-Production of first (meth) acrylic copolymer 2-
The first (meth) acrylic copolymer was produced in the same manner as in Production Example 1 except that the amount of 2-ethylhexyl acrylate (2EHA) was changed to 45 parts and the amount of M5300 was changed to 2 parts in Production Example 1. Solution A-2 was prepared.
The obtained first (meth) acrylic copolymer had a weight average molecular weight (Mw) of 520,000 and a dispersity (Mw / Mn) of 8.0.

(Production Example 3)
-Production of first (meth) acrylic copolymer 3-
The first (meth) acrylic copolymer was produced in the same manner as in Production Example 1 except that the amount of 2-ethylhexyl acrylate (2EHA) was changed to 43 parts and the amount of M5300 was changed to 4 parts in Production Example 1. Solution A-3 was prepared.
The obtained first (meth) acrylic copolymer had a weight average molecular weight (Mw) of 480,000 and a dispersity (Mw / Mn) of 7.7.

(Production Example 4)
-Production of first (meth) acrylic copolymer 4-
In Production Example 1, the same procedure as in Production Example 1 except that 1 part of light acrylate HO-AMS (HOAMS, manufactured by Kyoei Chemical Co., Ltd.) was used instead of M5300 as the monomer represented by the general formula (1a). Thus, a first (meth) acrylic copolymer solution A-4 was produced.
The obtained first (meth) acrylic copolymer had a weight average molecular weight (Mw) of 500,000 and a dispersity (Mw / Mn) of 8.4.

(Production Example 5)
-Production of first (meth) acrylic copolymer 5-
In Production Example 1, the first (meth) was the same as Production Example 1 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 parts. Acrylic copolymer solution A-5 was produced.
The weight average molecular weight (Mw) of the obtained first (meth) acrylic copolymer was 540,000, and the dispersity (Mw / Mn) was 6.9.

(Production Example 6)
-Production of first (meth) acrylic copolymer 6-
In Production Example 1, the first (meth) was the same as Production Example 1 except that the amount of butyl acrylate (BA) was changed to 0 parts and the amount of 2-ethylhexyl acrylate (2EHA) was changed to 96 parts. Acrylic copolymer solution A-6 was produced.
The obtained first (meth) acrylic copolymer had a weight average molecular weight (Mw) of 410,000 and a dispersity (Mw / Mn) of 8.3.

(Production Example 7)
-Production of (meth) acrylic copolymer C1-
(Meth) acrylic copolymer solution B in the same manner as in Production Example 1 except that the amount of 2-ethylhexyl acrylate (2EHA) was changed to 47 parts and M5300 was changed to unblended (0 parts) in Production Example 1. -1 was produced.
The obtained (meth) acrylic copolymer had a weight average molecular weight (Mw) of 530,000 and a dispersity (Mw / Mn) of 8.9.

(Production Example 8)
-Production of (meth) acrylic copolymer C2-
In Production Example 1, the same procedure as in Production Example 1 was conducted except that the amount of 2-ethylhexyl acrylate (2EHA) was 46.5 parts, and 0.5 parts of acrylic acid (AA) was used instead of M5300 (Metal) ) Acrylic copolymer solution C-2 was produced.
The obtained (meth) acrylic copolymer had a weight average molecular weight (Mw) of 500,000 and a dispersity (Mw / Mn) of 8.3.

(Production Example 9)
-Production of (meth) acrylic copolymer C3-
In Production Example 1, the same procedure as in Production Example 1 was conducted except that the amount of 2-ethylhexyl acrylate (2EHA) was 46.5 parts, and 0.5 parts of methacrylic acid (MAA) was used instead of M5300 (Metal) ) Acrylic copolymer solution C-3 was produced.
The resulting (meth) acrylic copolymer had a weight average molecular weight (Mw) of 490,000 and a dispersity (Mw / Mn) of 8.3.

(Production Example 10)
-Production of second (meth) acrylic copolymer 1-
A four-necked flask equipped with a stirring blade, a thermometer, a nitrogen gas inlet tube, a cooler, and a dropping funnel, 90 parts of n-butyl methacrylate (n-BMA), and methoxypolyethylene glycol methacrylate (polyalkyleneoxy group-containing monomer) The average number of ethyleneoxy group repeats is 23) 10 parts, 0.8 parts of AIBN as a polymerization initiator and 400 parts of ethyl acetate are introduced, nitrogen gas is introduced while gently stirring, and the liquid temperature in the flask is 70 ° C. Then, a polymerization reaction was carried out for 6 hours to prepare a second (meth) acrylic copolymer solution B-1 having a solid content of 20%.
The weight average molecular weight of the obtained second (meth) acrylic copolymer was 7,000.

<Example 1>
In a four-necked flask equipped with a stirring blade, a thermometer, a cooler, and a dropping funnel, the first (meth) acrylic copolymer solution A-1 (resin A in the table) obtained above is converted into a solid content. 100 parts, 0.4 part of the second (meth) acrylic copolymer solution B-1 (resin B in the table) in terms of solid content, SH-3773M (Toray Dow Corning Co., Ltd.) as a specific polysiloxane compound Manufactured, side chain polyether-modified silicone, polyether end hydroxyl group) 0.1 parts, LiCF ₃ SO ₃ (Morita Chemical Co., Ltd., LiTFS) 0.05 parts, respectively, the liquid temperature in the flask was charged The mixture was stirred at 4.0C for 4.0 hours to obtain a (meth) acrylic copolymer mixed solution.
2.5 parts of the product name: Desmodur N3300 [HMDI trimer type, solid content: 100% by weight; manufactured by Sumika Bayer Urethane Co., Ltd.] is added as a polyisocyanate compound, and the mixture is sufficiently stirred to adhere to the surface protective film. An adhesive composition (hereinafter, also simply referred to as “adhesive composition”) was obtained.
This pressure-sensitive adhesive composition had a sufficient pot life.
Using the obtained pressure-sensitive adhesive composition, a test surface protective film was prepared according to the following method for preparing a test surface protective film, and various physical property tests were performed. The obtained results are shown in Table 1.

(1) Production of surface protective film for test The pressure-sensitive adhesive composition was applied on a release paper surface-treated with a silicone-based release agent so that the coating amount after drying was 20 g / m ^2. After drying with a hot air circulation dryer at 60 ° C. for 60 seconds to form a pressure-sensitive adhesive layer, the pressure-sensitive adhesive layer surface is in contact with a polyethylene terephthalate (PET) film [trade name: E5001; manufactured by Toyobo Co., Ltd.] Then, after pressure bonding through a pressure nip roll, the surfaces were cured for 10 days in an environment of 23 ° C. and 50% RH to obtain a test surface protective film.

(2) Measurement of adhesive strength After the test surface protective film prepared in (1) was cut into 25 mm × 150 mm, the release paper was peeled off from the surface protective film piece, and antiglare treatment was performed using a desktop laminating machine. A test sample was prepared by pressure bonding to a polarizing film [trade name: SQ-1852AP-AG6; manufactured by Sumitomo Chemical Co., Ltd.].
This test sample was allowed to stand for 24 hours in an environment of 23 ° C. and 50% RH (conditioning treatment), and then the surface protective film was peeled off from the polarizing film along with the adhesive layer in the long side (150 mm) direction. The adhesive strength was measured 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 adhesive layer (contamination evaluation)
The test surface protective film prepared in the above (1) was left for 48 hours in an environment of 60 ° C. and 90% RH. After leaving for 1 hour in an environment of 23 ° 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. 2 μl of pure water is dropped on the surface of the pressure-sensitive adhesive layer, and after 30 seconds, the contact angle of water is measured using a contact angle measurement device (Contact angle meter CA-D), according to the following evaluation criteria. The contamination on the adherend was evaluated.
~Evaluation criteria~
AA: The contact angle was 90 ° or more.
A: The contact angle was 80 ° or more and less than 90 °.
B: The contact angle was 50 ° or more and less than 80 °.
C: The contact angle was less than 50 °.

(4) Measurement of surface resistance value Release paper was peeled off from the test surface protective film prepared in the above (1), and the surface resistance value of the exposed adhesive layer surface was measured by a surface resistance measuring device (Advantest Co., Ltd .: R12704 RESISTIVITY CHAMBER). ) And the antistatic property was evaluated according to the following evaluation criteria.
~Evaluation criteria~
AA: The surface resistance value was less than 1.0E + 11 (Ω / □).
A: The surface resistance value was 1.0E + 11 (Ω / □) or more and less than 5.0E + 11 (Ω / □).
B: The surface resistance value was 5.0E + 11 (Ω / □) or more and less than 1.0E + 12 (Ω / □).
C: The surface resistance value was 1.0E + 12 (Ω / □) or more.

(5) Peeling voltage measurement After the test surface protective film prepared in the above (1) was cut to 25 mm × 150 mm, this surface protective film piece was antiglare-treated using a desktop laminator [Products Name: SQ-1852AP-AG6; manufactured by Sumitomo Chemical Co., Ltd.] was used as a test sample. This sample was allowed to stand for 24 hours under the conditions of 23 ° C. and 50% RH (conditioning treatment), and then peeled off at 180 ° and at a peeling speed of 30 m / min (high-speed peeling conditions). The potential (kV) of the polarizing plate surface generated at this time is fixed at a position of 10 mm from the polarizing plate in a direction perpendicular to the surface thereof by a potential measuring machine [KSD-0303 manufactured by Kasuga Electric Co., Ltd.]. It was measured. The measurement was performed in an environment of 23 ° C. and 50% RH.

<Example 2 to Example 13>
In Example 1, except that each component used for the preparation of the pressure-sensitive adhesive composition for the surface protective film was changed as shown in Table 1 and Table 2, respectively, the adhesive for the surface protective film was performed in the same manner as in Example 1. An agent composition was prepared, and various physical property tests were conducted in the same manner. The obtained results are shown in Tables 1 and 2.

<Comparative Examples 1 to 4>
In Example 1, except that each component used for the preparation of the pressure-sensitive adhesive composition for the surface protective film was changed as shown in Table 2, the pressure-sensitive adhesive composition for the surface protective film was changed in the same manner as in Example 1. It was prepared and various physical property tests were conducted in the same manner. The obtained results are shown in Table 2.

In addition, the symbol in Table 1 and Table 2 is as follows.
BA: butyl acrylate; 2EHA: 2-ethylhexyl acrylate; 4HBA: 4-hydroxybutyl acrylate; M5300: manufactured by Toagosei Co., Ltd., Aronix M-5300, ω-carboxy-polycaprolactone (n≈2) monoacrylate; HOAMS: Kyoeisha 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 number of ethyleneoxy group repeats is 23);
N3300: Desmodur N3300 [hexamethylene diisocyanate trimer, manufactured by Sumika Bayer Urethane Co., Ltd.];
SH-3773M: manufactured by Toray Dow Corning Co., Ltd., side chain polyether-modified silicone, polysiloxane compound represented by general formula (3); FZ-2162: manufactured by Toray Dow Corning Co., Ltd., side chain polyether Modified silicone, polysiloxane compound represented by the general formula (3);
SH-8400: manufactured by Toray Dow Corning Co., Ltd., side chain polyether-modified silicone;
AS agent: antistatic agent; LiTFSI: 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 adhesiveness, suppression of generation of static electricity due to peeling charging, and low contamination of the adherend.

[Evaluation of familiarity]
About the surface protection film for a test produced using the adhesive composition produced in Examples 1 to 13, after being cut to 200 mm × 150 mm, the release film was peeled off and the adhesive layer surface was antiglare-treated polarizing film At 23 ° C. and 50% RH, it was pasted from the center part, and when wetting time by natural gravity was measured, it took less than 60 seconds to fully adapt to the edge in all samples, and excellent conformability showed that.

Claims (6)

A first (meth) acrylic copolymer comprising a first structural unit represented by the following general formula (1) and a second structural unit derived from a monomer having a hydroxy group;
A polyether-modified silicone having a hydroxy group at the end of the polyether;
An alkali metal salt,
A pressure-sensitive adhesive composition containing

(In General Formula (1), R ¹ represents a hydrogen atom or a methyl group. L is a divalent compound composed of at least one selected from the group consisting of an alkylene group, an arylene group, a carbonyl group and an oxygen atom. Indicates a linking group) 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). The pressure-sensitive adhesive composition according to claim 1.

(In the general formulas (2a) and (2b), R ^{21 to} R ²⁴ each independently represents an alkylene group having 1 to 12 carbon atoms or an arylene group having 6 to 10 carbon atoms. M represents a number from 1 to 10)   The pressure-sensitive adhesive composition according to claim 1 or 2, wherein the content of the first structural unit in the (meth) acrylic copolymer is 0.5% by mass to 5% by mass.   The content of the polyether-modified silicone is 0.05 part by mass to 0.50 part by mass with respect to 100 parts by mass of the (meth) acrylic copolymer. 2. The pressure-sensitive adhesive composition according to 1.   5. The composition further comprises a second (meth) acrylic copolymer containing a structural unit having a polyalkyleneoxy group and having a lower molecular weight than the first (meth) acrylic copolymer. The pressure-sensitive adhesive composition according to any one of the above. A polyester substrate;
A pressure-sensitive adhesive layer provided on the polyester base material and derived from the pressure-sensitive adhesive composition according to any one of claims 1 to 5,
An optical member surface protective film comprising: