JP6246021B2 - 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 device, 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 adhesively coated with a surface protective film so that the surface thereof is not contaminated or damaged during each process such as punching, inspection, transportation, and assembly of a liquid crystal display panel. This surface protective film is peeled off from the optical member when the surface protection is no longer necessary.

  Such a surface protective film may adhere to the surface of the optical member to such an extent that the optical member does not deviate or fall off from the surface while surface protection of the optical member is required. Required. On the other hand, the surface protective film is adhered so that the optical member and the liquid crystal cell are not damaged by the distortion caused by the peeling, and the optical member is peeled off from the liquid crystal cell. It is required that it can be easily peeled off. Further, the surface protective film is required to have no residue derived from the surface protective film on the optical member upon peeling, that is, to have low contamination to the adherend (hereinafter also simply referred to as “contamination”). It is done.

  In addition, since the optical member and the surface protective film are generally made of plastic, they have high electrical insulation, and static electricity is likely to occur during friction and peeling. When static electricity is generated when the surface protective film is peeled off from the optical member, dust and dust are adsorbed on the surface of the optical film, resulting in inconvenience for the product. Further, if a large amount of static electricity is generated when the protective film is peeled off, the circuit of the display member may be destroyed. Therefore, it is desirable that the surface protective film exhibits good antistatic properties when peeled from the optical member.

  As a technique related to antistatic, a pressure-sensitive adhesive composition containing an alkali metal salt or a dimethylpolysiloxane compound has been disclosed in order to improve antistatic properties (see, for example, Patent Documents 1 and 2).

  Moreover, the resin film with an adhesive using the ionic compound which is solid at room temperature as an antistatic component is disclosed (for example, refer patent document 3). Moreover, the surface protection sheet which contains an ionic compound as an antistatic agent is disclosed (for example, refer patent document 4). Furthermore, there is also a disclosure relating to an adhesive composition containing an ion pair such as an ionic liquid (see, for example, Patent Document 5).

International Publication No. 2012/133343 JP 2009-275128 A JP 2009-79205 A JP 2009-19162 A JP 2009-155586 A

As described above, various studies have been made on the antistatic properties of pressure-sensitive adhesives, but in reality, it is impossible to avoid bleed-out of antistatic components if an attempt is made to sufficiently suppress the generation of static electricity due to peeling. Is the actual situation. The bleed-out is one of the causes that contaminate the adherend and significantly reduce the commercial value.
Then, this invention makes it a subject to provide the adhesive composition which can form the adhesive film with little static electricity generate | occur | produced at the time of peeling, and to which an adherend is little contaminated.

Specific means for solving the above problems are as follows.
<1> a (meth) acrylic copolymer having an acidic group and a hydroxyl group;
An ionic solid containing an organic cation and having a melting point of 25 ° C. or higher;
A polyether-modified dimethylpolysiloxane compound having a hydroxyl group as a reactive group;
A polyisocyanate compound as a crosslinking agent;
Including
The content of the ionic solid is 0.2 parts by mass or less with respect to 100 parts by mass of the (meth) acrylic copolymer,
Content of the said polyether modified dimethylpolysiloxane compound is an adhesive composition which is 1 mass part or less with respect to 100 mass parts of said (meth) acryl copolymers.

<2> before Symbol weight ratio of the polyether-modified dimethylpolysiloxane compound to the crosslinking agent (polyether-modified dimethylpolysiloxane compound / crosslinking agent) is a 3/100 to 20/100, according to <1> Adhesive composition.

< 3 > The pressure-sensitive adhesive composition according to <1> or < 2 >, wherein the acid value of the (meth) acrylic copolymer is greater than 0 and 1 or less.

< 4 > The pressure-sensitive adhesive composition according to any one of <1> to < 3 >, which is used for an optical member surface protective film.

< 5 > a base material;
An adhesive layer provided on the base material and derived from the adhesive composition according to any one of <1> to < 3 >,
An optical member surface protective film comprising:

  ADVANTAGE OF THE INVENTION According to this invention, the adhesive composition which can form the adhesive film with little static electricity generate | occur | produced at the time of peeling, and a to-be-adhered body contamination, 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 this specification, the amount of each component in the composition is the sum of the plurality of types of substances corresponding to the component, unless a specific case is used in combination. Means quantity.
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 contains a (meth) acrylic copolymer having an acidic group and a hydroxyl group (hereinafter sometimes referred to as “specific (meth) acrylic copolymer”) and an organic cation and has a melting point of 25. An ionic solid having a temperature of at least ° C. (hereinafter sometimes referred to as “specific ionic solid”) and a polyether-modified dimethylpolysiloxane compound having a hydroxyl group as a reactive group (hereinafter referred to as “specific polysiloxane compound”) And a polyisocyanate compound as a crosslinking agent, and the content of the ionic solid is 0.2 parts by mass or less with respect to 100 parts by mass of the (meth) acrylic copolymer, The content of the polyether-modified dimethylpolysiloxane compound is 1 part by mass or less with respect to 100 parts by mass of the (meth) acrylic copolymer. Such an adhesive composition can be preferably applied to an optical member surface protective film.

  By setting it as the adhesive composition of the said structure, the adhesive film produced by this has little static electricity which generate | occur | produces at the time of peeling, and there is little contamination of a to-be-adhered body. This can be thought of as follows.

  The specific ionic solid containing an organic cation and having a melting point of 25 ° C. or more functions as an antistatic agent. In the present invention, the specific ionic solid is used together with the specific polysiloxane compound, thereby interacting with the polyether group of the specific polysiloxane compound to form a conductive path. Therefore, the pressure-sensitive adhesive composition of the present invention exhibits excellent antistatic properties even when the specific ionic solid is used in an amount smaller than the amount generally used. Moreover, since specific ionic solid can be made into a small quantity, the quantity which specific ionic solid bleeds out on the surface of an adhesive composition decreases, and the contamination with respect to a to-be-adhered body is suppressed.

  In the present invention, a specific (meth) acrylic copolymer having an acidic group and a hydroxyl group is used. For example, when only a monomer having no functional group is used in addition to a monomer having a hydroxyl group as a synthesis raw material of the (meth) acrylic copolymer, a monomer having a hydroxyl group from the viewpoint of copolymerization Increases body consumption speed. Therefore, at the end of the polymerization reaction, a (meth) acrylic copolymer having almost no functional group is produced, and a (meth) acrylic copolymer having a functional group (that is, a hydroxyl group) and almost no functional group (meta) ) Acrylic copolymer is mixed. Since a (meth) acrylic copolymer having almost no functional group is difficult to be crosslinked, when a pressure-sensitive adhesive film containing the (meth) acrylic copolymer is peeled from the adherend, the (meth) acrylic copolymer having almost no functional group is the adherend. Easily adhere to the adherend.

  On the other hand, as a raw material for synthesizing a (meth) acrylic copolymer, for example, in addition to a monomer having a hydroxyl group, a monomer having an acidic group is used in addition to a monomer having no functional group. In this case, the consumption rate of the monomer having a hydroxyl group becomes slow. Therefore, even in the final stage of the polymerization reaction, a (meth) acrylic copolymer having a certain amount of hydroxyl groups is produced. Therefore, since there is almost no (meth) acrylic copolymer which is not cross-linked, the pressure-sensitive adhesive film containing the (meth) acrylic copolymer hardly remains on the adherend and can prevent contamination of the adherend.

Furthermore, in the present invention, the polyether-modified dimethylpolysiloxane compound has a hydroxyl group as a reactive group. The specific polysiloxane compound is cross-linked by the reactive group, and the free non-cross-linked specific polysiloxane compound is reduced. As a result, it is possible to prevent contamination of the adherend due to the free specific polysiloxane compound which is not crosslinked.

[(Meth) acrylic copolymer]
The pressure-sensitive adhesive composition in the present invention contains at least one specific (meth) acrylic copolymer having an acidic group and a hydroxyl group. The pressure-sensitive adhesive composition may further contain a (meth) acrylic copolymer different from the specific (meth) acrylic copolymer, if 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.

  The specific (meth) acrylic copolymer includes a first structural unit having an acidic group and a second structural unit having a hydroxyl group. The first structural unit is not particularly limited as long as it is a structural unit derived from a monomer having an acidic group, a monomer that forms the second structural unit, and a polymerizable group that can form a copolymer. . As the first structural unit, a structural unit derived from a monomer having a carboxy group is preferable. Examples of the structural unit derived from the monomer having a carboxy group include a structural unit derived from (meth) acrylic acid and a structural unit derived from a (meth) acrylic acid ester having a carboxy group. Examples of the structural unit derived from the (meth) acrylic acid ester having a carboxy group include a structural unit represented by the following general formula (1). The first structural unit having an acidic group is preferably a structural unit represented by the following general formula (1).

In the 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, and R ¹ represents A hydrogen atom or a methyl group is shown. However, when L contains an oxygen atom, the oxygen atom is contained together with at least one selected from the group consisting of an alkylene group, an arylene group and a carbonyl group, and is bonded to —CO—.

  When the specific (meth) acrylic copolymer having the structural unit represented by the general formula (1) is used together with the specific polysiloxane compound described later and the specific ionic solid, the specific polysiloxane compound and the specific ionic solid are used. The effect of reducing the surface resistance value of the pressure-sensitive adhesive composition resulting from the above can be effectively exhibited.

  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 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 a divalent linking group represented by the following general formula (2a) or general formula (2b) from the viewpoint of antistatic properties and contamination to the adherend. A linking group is preferred.

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 groups for R ²¹ and R ²² each independently preferably have 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 each independently a phenylene group or a naphthylene group, and more preferably a phenylene group.

In the general formula (2a), R ²¹ and R ²² are each independently preferably an alkylene group having 1 to 12 carbon atoms, and preferably 2 to 6 carbon atoms from the viewpoint of antistatic properties and contamination to an adherend. The alkylene group is more preferably a C2-C6 linear or branched alkylene group.

  In general formula (2a), n represents the number of 0-10. When the specific (meth) acrylic copolymer contains only one type of structural unit represented by general formula (1), n is an integer, and when it contains two or more types, n is a rational number that is an average value. It becomes. n is preferably from 0 to 4, more preferably from 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.

  In General formula (2b), m represents the number of 1-10. When the specific (meth) acrylic copolymer contains only one type of structural unit represented by the general formula (1), m is an integer, and when it contains two or more types, m is a rational number that is an average value. It becomes. m is preferably from 1 to 4, and more preferably from 1 to 2.

  The structural unit represented by the general formula (1) is obtained by, for example, copolymerizing a monomer represented by the following general formula (1a) together with other monomers constituting the specific (meth) acrylic copolymer. Thus, it can be introduced into the specific (meth) acrylic copolymer.

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). These monomers can use what is marketed as "Aronix M-5600", "Aronix M-5300" (above, Toagosei Co., Ltd. make, brand name) etc., for example.

  In addition, among the monomers represented by the general formula (1a), L is a monomer represented by the general formula (2b). 2- (meth) acryloyloxyethyl succinic acid, 2- (meth) acryloyl Examples thereof include oxyethyl 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)” (above, What is marketed as Kyoeisha Co., Ltd., brand name) etc. can be used.

The content of the first structural unit having an acidic group in the specific (meth) acrylic copolymer is preferably 0.005% by mass to 1% by mass, and 0.025% by mass to 0.5% by mass. More preferably, it is more preferably 0.025% by mass to 0.25% by mass.
When the content of the first structural unit having an acidic group is 0.005% by mass or more, the contamination is further lowered. Moreover, the pot life of an adhesive composition is long that the content rate of the 1st structural unit which has an acidic group is 1 mass% or less, and it is excellent in workability | operativity.

  The specific (meth) acrylic copolymer contains at least one second structural unit having a hydroxyl group. The monomer having a hydroxyl group forming the second structural unit is a monomer having at least one hydroxyl group and a polymerizable group capable of forming a copolymer with the monomer forming the first structural unit. If it is a body, it will not restrict | limit in particular, It can select from the monomer used normally, and can use it suitably.

  As a monomer which has a hydroxyl group, the monomer which has a hydroxyl group and an ethylenically unsaturated bond group can be mentioned, for example. Specific examples of the monomer having a hydroxyl group include 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 3-hydroxypropyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, 3- Methyl-3-hydroxybutyl (meth) acrylate, 1,3-dimethyl-3-hydroxybutyl (meth) acrylate, 2,2,4-trimethyl-3-hydroxypentyl (meth) acrylate, 2-ethyl-3-hydroxy (Meth) such as hexyl (meth) acrylate, glycerin mono (meth) acrylate, polypropylene glycol mono (meth) acrylate, polyethylene glycol mono (meth) acrylate, poly (ethylene glycol-propylene glycol) mono (meth) acrylate Acrylate compounds; N- methylol (meth) acrylamide, N- hydroxyethyl having (meth) hydroxyl group of acrylamide (meth) acrylamide compound; and the like; allyl alcohol, unsaturated alcohols, such as methallyl alcohol.

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

  In the specific (meth) acrylic copolymer, the content of the second structural unit derived from the monomer having a hydroxyl group is 0.1% by mass or more in the total mass of the specific (meth) acrylic copolymer. It is preferably 10.0% by mass or less, more preferably 2.0% by mass or more and 8.0% by mass or less, and further preferably 2.0% by mass or more and 5.0% by mass or less. 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 the conformability (wetting property) to a to-be-adhered body 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 specific (meth) acrylic copolymer is not particularly limited. From the viewpoint of contamination on the adherend, the content ratio of the first structural unit to the second structural unit (first structural unit / second structural unit) is 1/2000 to 5/1 on a mass basis. It is preferably 1/350 to 1/8, more preferably 1/200 to 1/50.

  The total content of the first structural unit and the second structural unit in the specific (meth) acrylic copolymer is not particularly limited. From the viewpoint of contamination to the adherend, the total content of the first structural unit and the second structural unit is preferably 1% by mass to 15% by mass, and preferably 2% by mass to 10% by mass. More preferably, it is more preferably 3% by mass or more and 8% by mass or less.

The specific (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 specific (meth) acrylic copolymer may contain a single third structural unit derived from an alkyl (meth) acrylate, or may contain two or more, and preferably contains two or more. . When the specific (meth) acrylic copolymer contains two types of the third structural unit, one is a structural unit derived from an alkyl (meth) acrylate having a linear or branched alkyl group having 1 to 5 carbon atoms. 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, and one is a linear chain having 2 to 5 carbon atoms. The other is a structural unit derived from an alkyl (meth) acrylate having a branched alkyl group having 6 to 10 carbon atoms, More preferred. As the alkyl (meth) acrylate having a linear alkyl group having 2 to 5 carbon atoms, n-butyl (meth) acrylate is preferable.

  By adjusting the content of structural units derived from alkyl (meth) acrylates having a linear alkyl group having 2 to 5 carbon atoms, the amount of ionic solid that bleeds out to the surface of the pressure-sensitive adhesive composition varies. However, the antistatic property tends to be improved. From this viewpoint, the content of the structural unit derived from the alkyl (meth) acrylate having a linear alkyl group having 2 to 5 carbon atoms is 0% by mass in the total mass of the (meth) acrylic copolymer. More than 30% by mass, more preferably 1% by mass to 25% by mass, still more preferably 5% by mass to 25% by mass, and more preferably 5% by mass to 15% by mass. It is particularly preferred.

  When the specific (meth) acrylic copolymer includes the third structural unit, the total content of the third structural unit is 60% by mass or more and 99.9% in the total mass of the specific (meth) acrylic copolymer. It is preferably at most mass%, more preferably at least 72 mass% and at most 99.5 mass%, still more preferably at least 85 mass% and at most 99 mass%. When the total content of the third structural unit is equal to or more than the lower limit value, the conformability (wetting property) tends to become better. Further, if the total 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 specific (meth) acrylic copolymer may further contain other structural units other than the first structural unit, the second structural unit, and the third structural unit, if necessary. 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.

  Furthermore, as another monomer that forms a structural unit, it 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. Examples of the functional monomer include monomers having a functional group such as a substituted or unsubstituted amide group, a substituted or unsubstituted amino group, an alkoxy group, an epoxy group, a mercapto group, and a silicon-containing group. . A monomer having two or more radically polymerizable groups in the molecule can also be used.

  Specific examples of these functional monomers include (meth) acrylamide, diacetone acrylamide, Nn-butoxymethyl (meth) acrylamide, N-isobutoxymethyl (meth) acrylamide, N, N-dimethyl ( Substituted or unsubstituted amide group-containing monomers such as meth) acrylamide and N-methyl (meth) acrylamide; aminoethyl (meth) acrylate, N, N-dimethylaminoethyl (meth) acrylate, N, N-diethylaminoethyl Substituted or unsubstituted amino group-containing monomers such as (meth) acrylate; 2-methoxyethyl (meth) acrylate, 2-ethoxyethyl (meth) acrylate, 2-n-butoxyethyl (meth) acrylate, 2-methoxy Ethoxyethyl (meth) acrylate, 2-ethoxyeth Alkoxy group-containing monomers such as ciethyl (meth) acrylate, 2-n-butoxyethoxyethyl (meth) acrylate, methoxypolyethylene glycol mono (meth) acrylate, methoxypolyethylene glycol monomethacrylate; glycidyl (meth) acrylate, glycidyl allyl ether , Epoxy group-containing monomers such as glycidyl methallyl ether; mercapto group-containing monomers such as allyl mercaptan; vinyltrichlorosilane, vinyltribromosilane, vinyltrimethoxysilane, vinyltriethoxysilane, vinyltri-n-propoxysilane, Vinyltriisopropoxysilane, vinyltri-n-butoxysilane, vinyltris (2-methoxyethoxy) silane, vinyltris (2-hydroxymethoxyethoxy) silane Vinyltriacetoxysilane, vinyldiethoxysilanol, vinylethoxysiladiol, vinylmethyldiethoxysilane, vinyldimethylethoxysilane, vinylmethyldiacetoxysilane, allyltrimethoxysilane, allyltriethoxysilane, 3- (meth) acryloxypropyl Trimethoxysilane, 3- (meth) acryloxypropyltriethoxysilane, 3- (meth) acryloxypropyltris (2-methoxyethoxy) silane, 3- (meth) acryloxypropylmethyldiethoxysilane, 3- (meta Monomer groups having silicon-containing groups such as acryloxypropyldimethylethoxysilane, 3- (meth) acryloxypropyldimethylmethoxysilane, 2- (meth) acrylamidoethyltriethoxysilane; Can be mentioned.

  When the specific (meth) acrylic copolymer includes other structural units, the content of other structural units is preferably 30% by mass or less in the total mass of the specific (meth) acrylic copolymer, It is more preferably 20% by mass or less, and further preferably 10% by mass or less. When the content of other structural units is less than or equal to the above upper limit value, there is a tendency that the balance between low-speed peeling and high-speed peeling adhesive force can be improved.

  The acid value of the specific (meth) acrylic copolymer is more than 0 and 1 or less, preferably more than 0 and 1.8 or less, more preferably more than 0 and 1 or less. More preferably, it is 0.01 or more and 0.5 or less, and particularly preferably 0.05 or more and 0.5 or less. When the acid value of the (meth) acrylic copolymer exceeds 0, in the synthesis of the specific (meth) acrylic copolymer, a (meth) acrylic copolymer having no hydroxyl group is hardly generated. In the produced adhesive film, the (meth) acrylic copolymer hardly remains on the adherend, and contamination of the adherend can be prevented. When the acid value of the specific (meth) acrylic copolymer is 1.0 or less, the initial curability is excellent. When the initial curing rate is lowered, workability is inferior, and a winding mark may remain when the pressure-sensitive adhesive sheet is wound around a core.

The acid value of the (meth) acrylic copolymer is measured by the following method.
(1) About 5 g of (meth) acrylic copolymer is placed in an Erlenmeyer flask, the solvent is removed at room temperature under reduced pressure, and then dried in a hot air dryer at 105 ° C. to obtain a polymer sample.
(2) A polymer sample is dissolved in 100 ml of a mixed solvent (volume ratio: toluene / ethanol = 50/50) to obtain a sample solution.
(3) Titrate the sample solution under the following conditions to measure the titration amount.
Titration solution: Ethanolic potassium hydroxide solution (0.1N, manufactured by Wako Pure Chemical Industries, Ltd., for volumetric analysis)
Indicator: Phenolphthalein (4) Oxidation is calculated from the following formula.
A = {(Y−X) × f × 5.61} / M
A: Acid value Y: Titration volume of sample solution (ml)
X: Titration volume of a solution containing only 100 ml of mixed solvent (ml)
f: Factor of titration solution M: Mass of polymer sample (g)

  The weight average molecular weight of the specific (meth) acrylic copolymer is not particularly limited. The weight average molecular weight (Mw) of the specific (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 specific (meth) acryl copolymer is more than the said lower limit, there exists a tendency which can suppress the 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.

  Moreover, it is preferable that the dispersity (Mw / Mn) which is a ratio of the weight average molecular weight (Mw) and the number average molecular weight (Mn) of a specific (meth) acrylic copolymer is 20 or less, A range is more preferable. If the value of the degree of dispersion (Mw / Mn) is equal to or less than the upper limit, 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 (meth) acryl copolymer are the values measured by the method 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 specific (meth) acrylic copolymer in an adhesive composition can be suitably selected according to the objective etc. The content of the specific (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. Is more preferable, and it is still more preferable that it is 90 to 98 mass%. 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.

  The specific (meth) acrylic copolymer can be produced by polymerizing monomers capable of forming the structural unit of the specific (meth) acrylic copolymer. 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. In producing the pressure-sensitive adhesive composition of the present invention using the copolymer obtained by polymerization, the specific (meth) acrylic copolymer is polymerized by a solution polymerization method because the treatment process can be performed relatively easily. It is preferable.

  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 at a reflux temperature of the organic solvent in a nitrogen stream. 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 a specific (meth) acrylic copolymer can be easily adjusted with reaction temperature, time, the amount of solvent, and the kind and quantity of a catalyst.

  Examples of the organic solvent used for polymerization of the specific (meth) acrylic copolymer include benzene, toluene, ethylbenzene, n-propylbenzene, t-butylbenzene, o-xylene, m-xylene, p-xylene, and tetralin. , Decalin, aromatic naphtha and other aromatic hydrocarbon compounds; n-hexane, n-heptane, n-octane, isooctane, n-decane, dipentene, petroleum spirit, petroleum naphtha, terpine oil, and other aliphatic or alicyclic groups Hydrocarbon compounds: ester compounds such as ethyl acetate, n-butyl acetate, n-amyl acetate, 2-hydroxyethyl acetate, 2-butoxyethyl acetate, 3-methoxybutyl acetate, methyl benzoate; acetone, methyl ethyl ketone, methyl isobutyl Ketone, isophorone, cyclohexanone, methylcyclohexa Ketone compounds such as ethylene; glycol ether compounds 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-propyl alcohol And alcohol compounds such as isopropyl alcohol, n-butyl alcohol, isobutyl alcohol, s-butyl alcohol, and t-butyl alcohol. These organic solvents can be used alone or in combination of two or more.

  As a polymerization initiator, it is possible to use an 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.

  Moreover, when manufacturing a specific (meth) acrylic copolymer, you may use a chain transfer agent as needed in the range which does not impair the objective and effect of this invention. Examples of the chain transfer agent include cyanoacetic acid; alkyl ester compound having 1 to 8 carbon atoms of cyanoacetic acid; bromoacetic acid; alkyl ester compound 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 and p-nitrotoluene; benzoquinone, 2,3,5,6-tetramethyl- benzoquinone derivatives such as p-benzoquinone; borane derivatives such as tributylborane; carbon tetrabromide, carbon tetrachloride, 1,1,2,2-tetrabromoethane, tribromoethylene, trichloroethylene, bromotrichloromethane, tribromomethane, Halogens such as 3-chloro-1-propene Hydrocarbon compounds; Aldehyde compounds such as chloral and fulleraldehyde: Alkyl mercaptan compounds having 1 to 18 carbon atoms; Aromatic mercaptan compounds such as thiophenol and toluene mercaptan; A hydroxyalkyl mercaptan compound having 1 to 12 carbon atoms; a terpene compound such as pinene and terpinolene; and the like.

The polymerization temperature is generally in the range of about 30 ° C to 180 ° C.
In producing the specific (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, this 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.

(Other (meth) acrylic copolymers)
In the pressure-sensitive adhesive composition of the present invention, other (meth) acrylic copolymers other than the specific (meth) acrylic copolymer having an acidic group and a hydroxyl group may be used in combination. When the pressure-sensitive adhesive composition contains another (meth) acrylic copolymer, the content can be appropriately selected depending on the purpose and the like, with respect to 100 parts by mass of the specific (meth) acrylic copolymer, It is preferably 2.0 parts by mass or less, more preferably 1.5 parts by mass or less, and further preferably 1.0 part by mass or less.

[Polyether-modified dimethylpolysiloxane compound having a hydroxyl group as a reactive group]
The pressure-sensitive adhesive composition contains at least one polyether-modified dimethylpolysiloxane compound (specific polysiloxane compound) having a hydroxyl group as a reactive group. Since the polyether-modified dimethylpolysiloxane compound has a hydroxyl group as a reactive group , the pressure-sensitive adhesive film produced thereby can be easily peeled off from the adherend, and contamination of the adherend is reduced.

  Since the specific polysiloxane compound has an effect of lowering the adhesive strength, it is considered that the adhesive film produced containing the specific polysiloxane compound has a lower adhesive strength and can be easily peeled off from the adherend.

  Moreover, it interacts by using a specific polysiloxane compound with a specific ionic solid, and exhibits an excellent antistatic agent even if the specific ionic solid is in a small amount. And since a specific ionic solid can be made into a small quantity, the contamination to the to-be-adhered body resulting from a specific ionic solid is suppressed.

Reactive groups in particular the polysiloxane compound, Ru hydroxyl der. In the specific polysiloxane compound, the content of the structural unit having a reactive group is preferably 100 or less, and more preferably 1 to 80.

The specific polysiloxane compound is a polysiloxane compound containing a structural unit derived from a dialkylsiloxane and a structural unit derived from an alkyl (hydroxypolyalkyleneoxyalkyl) siloxane from the viewpoint of antistatic properties and contamination on an adherend. It is preferable.
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 easy adjustment of adhesive strength, antistatic properties, and contamination on 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 1 to 100, and 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 improved.

Moreover, the repeating number p of a dimethylsiloxane structural unit is a number of 0-100, and it is preferable that it is a number of 1-80. When p 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.
Furthermore, the repeating number q of the methylpropylenesiloxane structural unit is 2 to 100, and 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.

  The polysiloxane compound represented by the general formula (3) 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, “SF8428”, “FZ-2162”, “SH3773M” [above, manufactured by Toray Dow Corning Co., Ltd.] and the like. Can be mentioned.

  Even if the polysiloxane compound represented by the general formula (3) is selected from the above-mentioned commercially available products, the unsaturated bond and the polysiloxane are bonded to the dimethylpolysiloxane main chain having silicon hydride. It can also be obtained by grafting an organic compound having an oxyethylene group by a hydrosilylation reaction.

The pressure-sensitive adhesive composition may contain a polysiloxane compound having a structure different from that of the specific polysiloxane compound in addition to the specific polysiloxane compound. However, when adding a polysiloxane compound that does not have reactivity with the crosslinking agent, it is preferable to keep the addition amount so as not to affect the contamination from the viewpoint of maintaining good contamination.
Examples of the polysiloxane compound having a structure different from that of the specific polysiloxane compound include a polysiloxane compound having a polyethyleneoxy group terminated with an alkoxy group, an acyloxy group, or the like.

  Specifically, for example, “FZ-77”, “FZ-2104”, “FZ-2110”, “FZ-2203”, “FZ-2207”, “FZ-2208”, “L-7001”, “L -7002 "," SH3749 "," SH8400 "[above, manufactured by Toray Dow Corning Co., Ltd.].

  When the pressure-sensitive adhesive composition contains a polysiloxane compound having a structure different from the specific polysiloxane compound, the content is preferably 0.05% by mass or less in the total mass of the polysiloxane compound. It is more preferable that it is 03 mass% or less.

  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 HLB value is determined according to the definition of the Griffin method calculated by the following formula 1, but 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 content of the specific polysiloxane compound is preferably 3/100 to 20/100 in terms of mass ratio (specific polysiloxane compound / crosslinking agent) to the crosslinking agent described later, and is 3/100 to 15/100. It is preferably 5/100 to 15/100, more preferably 5/100 to 10/100. When the content of the specific polysiloxane compound is 3 parts by mass or more with respect to 100 parts by mass of the crosslinking agent, both the adhesive force and the conformability (wetting property) to the adherend tend to be compatible. In the case of 20 parts by mass or less, free specific polysiloxane compounds that are not crosslinked are reduced, and contamination of the adherend due to the free specific polysiloxane compounds that are not crosslinked can be prevented.

  The content of the specific polysiloxane compound in the pressure-sensitive adhesive composition of the present invention is 1 part by mass or less, and 0.05 parts by mass or more and 0.5 parts by mass with respect to 100 parts by mass of the specific (meth) acrylic copolymer. It is preferably no greater than mass parts, more preferably no less than 0.05 mass parts and no greater than 0.4 mass parts, and even more preferably no less than 0.10 mass parts and no greater than 0.3 mass parts.

  When the content of the specific polysiloxane compound is 1 part by mass or less with respect to 100 parts by mass of the specific (meth) acrylic copolymer, the occurrence of contamination on the adherend is suppressed when the adhesive film is formed, Moreover, it can suppress that compatibility with a specific (meth) acrylic copolymer falls and white turbidity generate | occur | produces.

[Ionic solids]
The pressure-sensitive adhesive composition of the present invention contains at least one ionic solid containing an organic cation and having a melting point of 25 ° C. or higher. By using the specific ionic solid together with the specific polysiloxane compound, sufficient antistatic properties can be imparted even if the content of the specific ionic solid in the pressure-sensitive adhesive composition is reduced. Thereby, the contamination with respect to the to-be-adhered body of the adhesive composition resulting from specific ionic solid can be reduced significantly. In addition, since ionic solids have a lower hydrophilicity than alkali metal salts that have been widely used as antistatic agents, it is possible to drastically reduce contamination of the adhesive composition on the adherend. it can.

  The specific ionic solid is an ionic compound having a melting point of 25 ° C. or higher, and includes an organic cation and its counter ion. In a temperature range close to room temperature, the solid state is maintained, and the cation portion is an organic cation having low hydrophilicity, so that elution when included in the pressure-sensitive adhesive composition hardly occurs. That is, when the melting point of the ionic solid is in the range of less than 25 ° C., the ionic solid easily moves in the pressure-sensitive adhesive composition or the pressure-sensitive adhesive layer, and contamination on the adherend deteriorates. The melting point of the specific ionic solid is desirably higher, preferably 35 ° C. or higher, and more preferably 45 ° C. or higher. On the other hand, the melting point of the specific ionic solid is preferably 80 ° C. or less from the viewpoint of compatibility with the specific (meth) acrylic copolymer.

  Examples of the organic cation include an imidazolium cation, a pyridinium cation, an alkylpyrrolidinium cation, an ammonium cation, a sulfonium cation, and a phosphonium cation. Among these, when contained in the pressure-sensitive adhesive layer of the optical member surface protective film, a pyridinium cation and an imidazolium cation are preferable from the viewpoint of further reducing the charge when the release film provided on the pressure-sensitive adhesive layer is peeled off.

The anion part which becomes a counter ion of the organic cation is not particularly limited, and may be either an inorganic anion or an organic anion. Examples of anion moieties include chloride anions [Cl ⁻ ], bromide anions [Br ⁻ ], iodide anions [I ⁻ ], tetrachloroaluminate anions [AlCl ₄ ⁻ ], heptachlorodialuminate anions [Al ₂ Cl ₇ ^-], tetrafluoroborate anion [BF ₄ ^-], hexafluorophosphate anion [PF ₆ ^-], perchlorate anion [ClO ₄ ^-], nitrate anion [NO ₃ ^-], acetate anion _[CH 3 COO ^-] , Trifluoroacetate anion [CF ₃ COO ⁻ ], methanesulfonate anion [CH ₃ SO ₃ ⁻ ], trifluoromethanesulfonate anion [CF ₃ SO ₃ ⁻ ], p-toluenesulfonate anion [p-CH ₃ C ₆ H ₄ SO ₃ ^- ], Bis (trifluoromethanesulfonyl) imide anion [(CF ₃ SO ₂ ) ₂ N ⁻ ], tris (trifluoromethanesulfonyl) methanide anion [(CF ₃ SO ₂ ) ₃ C ⁻ ], hexafluoroarsenate anion [AsF ₆ ^-], hexafluoroantimonate anion [SbF ₆ ^-], hexafluoro niobate anions [NbF ₆ ^-], hexafluoro tantalate anion [TaF ₆ ^-], dimethyl phosphinate anion _{[(CH 3)} 2 POO ^-] , (Poly) hydrofluorofluoride anion [F (HF) _n ⁻ ] (n is about 1 to 3), dicyanamide anion [(CN) ₂ N ⁻ ], thiocyan anion [SCN ⁻ ], perfluorobutane sulfonate anion _[C 4 _F 9 SO ₃ ^-] Bis (pentafluoroethane sulfonyl) imide anion _{[(C 2 F 5 SO 2)} 2 N - ], perfluoro butanoate anion _[C 3 _F 7 COO ^-], (trifluoromethanesulfonyl) (trifluoromethane carbonyl) imide anion [(CF ₃ SO ₂ ) (CF ₃ CO) N ⁻ ] and the like.
Among these, in particular, a fluorine-containing anion containing a fluorine atom is preferable, and a hexafluorophosphate anion (PF ₆ ⁻ ) is preferable from the viewpoint of providing an ionic solid having excellent antistatic performance.

  Preferable examples of the ionic solid include pyridinium salts, imidazolium salts, alkylammonium salts, alkylpyrrolidinium salts, alkylphosphonium salts, and the like. Among these, pyridinium salts and imidazolium salts are preferable, and fluorine-containing anion salts of pyridinium cations and imidazolium cations are particularly preferable.

Specific examples of the ionic solid are listed below. However, the present invention is not limited to these.
(1) Examples of pyridinium salts include N-hexylpyridinium hexafluorophosphate (melting point: 45 ° C), N-octylpyridinium hexafluorophosphate, N-butyl-4-methylpyridinium hexafluorophosphate (melting point: 48 ° C), N-butyl-pyridinium hexafluorophosphate (melting point: 75 ° C.), 1-butyl-3-methylpyridinium bromide, 1-butyl-4-methylpyridinium bromide (melting point: 137 ° C.), 1-butyl-4-methylpyridinium chloride (Melting point: 158 ° C), 1-butylpyridinium bromide (melting point: 104 ° C), 1-butylpyridinium chloride (melting point: 132 ° C), 1-butylpyridinium hexafluorophosphate (melting point: 75 ° C), 1-ethylpyridinium Romaido (mp: 120 ° C.), and the like.

(2) As an example of an imidazolium salt, 1-methyl-3- (3,3,4,4,5,5,6,6,7,7,8,8,8-tridecafluorooctyl)- Imidazolium hexafluorophosphate (melting point: 80 ° C.), 1-butyl-1- (3,3,4,4,5,5,6,6,7,7,8,8,8-tridecafluorooctyl) -Imidazolium hexafluorophosphate (melting point: 120-121 ° C), 1-ethyl-3-methylimidazolium hexafluorophosphate (melting point: 61 ° C), 1-benzyl-3-methylimidazolium hexafluorophosphate (melting point: 136 ° C), 1-benzyl-3-methylimidazolium tetrafluoroborate (melting point: 77 ° C), 1-ethyl-3-methylimidazolium p-toluenesulfonate, 1- Cyl-3-methylimidazolium methanesulfonate (melting point: 75-80 ° C.), 1,2,3-trimethylimidazolium methyl sulfate (melting point: 113 ° C.), 1,3-dimethylimidazolium chloride (melting point: 125 ° C.) 1-butyl-2,3-dimethylimidazolium chloride (melting point: 99 ° C.), 1-butyl-3-methylimidazolium bromide (melting point: 78 ° C.), 1-butyl-3-methylimidazolium chloride (melting point: 65 ° C), 1-ethyl-3-methylimidazolium bromide (melting point: 74 ° C), 1-ethyl-3-methylimidazolium chloride (melting point: 80-84 ° C), 1-ethyl-3-methylimidazolium iodide (Melting point: 79 ° C.), 1-ethyl-2,3-dimethylimidazolium chloride (melting point: 18 ° C), 1-methylimidazolium chloride (melting point: 75 ° C), 1-aryl-3-methylimidazolium chloride (melting point: 55 ° C), 1-benzyl-3-methylimidazolium chloride (melting point: 70 ° C), etc. Is mentioned.

(3) Examples of alkylammonium salts include tetrabutylammonium hexafluorophosphate, tetrabutylammonium p-toluenesulfonate, cyclohexyltrimethylammonium bis (trifluoromethanesulfonyl) imide, tetra-n-butylammonium chloride (melting point: 75 ° C.) , Tetrabutylammonium bromide (melting point: 119 ° C.), tributylmethylammonium methyl sulfate (melting point: 62 ° C.), tetrabutylammonium bis (trifluoromethylsulfonyl) imide (melting point: 94-96 ° C.), tetraethylammonium trifluoromethanesulfonate ( Melting point: 161-163 ° C), tetrabutylammonium benzoate (melting point: 64-67 ° C), tetrabutylammonium methanes Rufate (melting point: 78-80 ° C.), tetrabutylammonium nonafluorobutanesulfonate (melting point: 50-53 ° C.), tetra-n-butylammonium hexafluorophosphate (melting point: 246 ° C.), tetrabutylammonium trifluoroacetate (melting point) : 74-76 ° C), tetrahexylammonium tetrafluoroborate (melting point: 90-92 ° C), tetrahexylammonium bromide (melting point: 97 ° C), tetrahexylammonium iodide (melting point: 99 ° C), tetraoctylammonium chloride ( Melting point: 50-54 ° C.), tetraoctyl ammonium bromide (melting point: 95-98 ° C.), tetraheptyl ammonium bromide (melting point: 89-91 ° C.), tetrapentyl ammonium bromide (melting point: 99 ° C.) , N- hexadecyl trimethyl ammonium hexafluorophosphate (mp: 185 ° C.), (2-hydroxyethyl) trimethylammonium bis (trifluoromethanesulfonyl) imide, and (2-hydroxyethyl) trimethyl ammonium dimethyl phosphinate like.

(4) Examples of alkylpyrrolidinium salts include N-butyl-N-methylpyrrolidinium hexafluorophosphate, 1-butyl-1-methylpyrrolidinium bromide (melting point: 160 ° C. or higher), 1-butyl- Examples thereof include 1-methylpyrrolidinium chloride (melting point: 114 ° C. or higher), 1-butyl-1-methylpyrrolidinium tetrafluoroborate (melting point: 152 ° C.), and the like.

(5) Examples of alkylphosphonium salts include tetrabutylphosphonium bromide (melting point: 104 ° C), tetrabutylphosphonium chloride (melting point: 62-66 ° C), tetrabutylphosphonium tetrafluoroborate (melting point: 96-99 ° C), Examples include tetrabutylphosphonium methanesulfonate (melting point: 59 to 62 ° C.), tetrabutylphosphonium p-toluenesulfonate (melting point: 54 to 57 ° C.), tributylhexadecylphosphonium bromide (melting point: 57 to 62 ° C.), and the like.

A specific ionic solid may be used individually by 1 type, and may be used in combination of 2 or more type.
As content of the specific ionic solid in an adhesive composition, it is 0.2 mass part or less with respect to 100 mass parts of specific (meth) acrylic copolymers. The pressure-sensitive adhesive composition of the present invention can exhibit excellent antistatic properties even when the content of the ionic solid is 0.2 parts by mass or less.
The content of the specific ionic solid in the present invention is preferably 0.05 parts by mass to 0.2 parts by mass with respect to 100 parts by mass of the specific (meth) acrylic copolymer, and 0.07 parts by mass to The amount is more preferably 0.18 parts by mass.

[Crosslinking agent]
The pressure-sensitive adhesive composition contains a polyisocyanate compound as a crosslinking agent. A polyisocyanate compound can be used individually by 1 type or in combination of 2 or more types, respectively.

And Po polyisocyanate compound, and a specific (meth) acrylic copolymer, and a specific polysiloxane compound, by each crosslinking reaction, and tack, improved well balanced and contaminating to adherends.

  Examples of the polyisocyanate compound include aromatic polyisocyanate compounds such as xylylene diisocyanate, diphenylmethane diisocyanate, triphenylmethane triisocyanate, and tolylene diisocyanate; for example, hydrogenated products of hexamethylene diisocyanate, isophorone diisocyanate, and aromatic polyisocyanate compounds. Examples thereof include aliphatic or alicyclic polyisocyanate compounds such as: dimers or trimers of these polyisocyanate compounds; adducts of these polyisocyanate compounds and polyol compounds such as trimethylolpropane. From the viewpoint of reactivity with the specific polysiloxane compound, among these polyisocyanate compounds, it is at least one selected from the group consisting of hexamethylene diisocyanate, hexamethylene diisocyanate dimer, trimer and adduct. The trimer of hexamethylene diisocyanate is particularly preferable. These polyisocyanate compounds can be used individually by 1 type or in mixture of 2 or more types.

  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 Kogyo Co., Ltd.), “Takenate D-110N ”,“ Takenate D-120N ”,“ Takenate M-631N ”,“ MT-Olestar NP1200 ”(above, manufactured by Mitsui Takeda Chemical Co., Ltd.) and the like are preferably used. be able to.

  The crosslinking agent is an amount such that the equivalent ratio of the functional group amount of the crosslinking agent to the functional group amount of the (meth) acrylic copolymer (crosslinking agent / (meth) acrylic copolymer) is 0.1 to 1.5. It is preferably used in an amount of 0.3 to 1.0, more preferably 0.5 to 0.8.

  The pressure-sensitive adhesive composition in the present invention preferably further contains a crosslinking catalyst in addition to the crosslinking agent from the viewpoint of increasing the initial curing rate. Examples of the crosslinking catalyst include organic tin compounds such as dibutyltin laurate and dioctyltin laurate, and organic zirconium compounds such as zirconium dibutoxybis (ethylacetoacetate). Among these crosslinking catalysts, an organic tin compound is preferable from the viewpoint of reactivity with a specific polysiloxane.

  When the adhesive composition in this invention contains a crosslinking catalyst, it is preferable that a chelating agent is further included. Examples of chelating agents include β-diketones and β-ketoesters. Examples of β-diketones and β-ketoesters include acetylacetone, methyl acetoacetate, ethyl acetoacetate, acetoacetate-n-propyl, and isopropyl acetoacetate. Of these chelating agents, acetylacetone is preferred because of the good balance between the pot life of the pressure-sensitive adhesive composition and the reaction rate.

[Other ingredients]
In addition to the specific (meth) acrylic copolymer, the specific polysiloxane compound, and the crosslinking agent, the pressure-sensitive adhesive composition in the present invention includes a weather resistance stabilizer, a tackifier, a plasticizer, a softening agent, a peeling aid, if necessary. An agent, a dye, a pigment, an inorganic filler, a surfactant and the like can be appropriately contained.

<Optical member surface protective film>
The optical member surface protective film of the present invention includes a base material and a pressure-sensitive adhesive layer derived from the pressure-sensitive adhesive composition of the present invention provided on the base material.
Since the pressure-sensitive adhesive layer is derived from the pressure-sensitive adhesive composition of the present invention, it constitutes a pressure-sensitive adhesive layer with less static electricity generated at the time of peeling and excellent antistatic properties and reduced contamination on the adherend. 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.
Base materials are polyester resin, acetate resin, polyethersulfone resin, polycarbonate resin, polyamide resin, polyimide resin, polyolefin resin, acrylic resin from the viewpoint of inspection and management of optical members through fluoroscopy. The film which consists of 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 a 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 at the time of peeling. The surface of the substrate on the side where the pressure-sensitive adhesive layer is provided may be subjected to a 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 of the present invention is provided.
As a method for forming the pressure-sensitive adhesive layer, for example, a method is adopted in which the pressure-sensitive adhesive composition is diluted as it is or with an appropriate solvent as necessary, and this is applied to a substrate and then dried to remove the solvent. can do.
First, the pressure-sensitive adhesive composition is applied onto a release sheet made of an appropriate film such as paper or polyester film that has been subjected to a release treatment with a silicone resin, and then dried by heating to form a pressure-sensitive adhesive layer. It is also possible to employ a method in which the pressure-sensitive adhesive layer side of the release sheet is pressed against a substrate and the pressure-sensitive adhesive layer is transferred to the protective film.

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

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

  When the adhesive strength of the pressure-sensitive adhesive layer is increased, workability during high-speed peeling in a large area is reduced, so that the adhesive strength (peeling force) at a peeling speed of 30 m / min (high-speed peeling) is less than 1.0 N / 25 mm. Preferably, it is less than 0.6 N / 25 mm.

  The optical member surface protective film 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 panel or the like, the protective film Are stacked on the optical member, and are used for each process such as punching, inspection, transportation, and assembly of the liquid crystal display panel. If necessary, heat and pressure treatment such as autoclave treatment and high-temperature aging treatment is performed. It is applied and peeled off from the optical member at the stage where surface protection becomes unnecessary.

  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 (meth) acrylic copolymer A-
In a reactor equipped with a thermometer, a stirrer, a nitrogen inlet tube and a reflux condenser, 20 parts of ethyl acetate and 10 parts of toluene were placed, and in another container, 15 parts of butyl acrylate (BA), 2 -81.995 parts of ethylhexyl acrylate (2EHA), 3 parts of 4-hydroxybutyl acrylate (4HBA) as a monomer having a hydroxyl group, M-5300 (Aronix M-5300, general formula (1a) as a monomer having an acidic group ), A monomer represented by Toagosei Co., Ltd.) is added and mixed to form a monomer mixture, 25% by mass of which is added to the reaction vessel, and then the air in the reaction vessel Was replaced with nitrogen gas, 0.02 part of azobisbutyronitrile (hereinafter referred to as AIBN) was added as a polymerization initiator, and the mixture was placed in the reaction vessel in a nitrogen atmosphere with stirring. And a compound temperature was raised to 70 ° C. to initiate the initial reaction. After the initial reaction was almost completed, the remaining monomer mixture 75% by mass, and a mixture of 20 parts of ethyl acetate, 10 parts of toluene and 0.2 part of AIBN were reacted for about 2 hours, respectively. Reacted for hours. 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 100 parts of toluene to obtain a (meth) acrylic copolymer A solution having a solid content of 35% by mass.
The acid value of (meth) acrylic copolymer A (indicated as “resin A” in the table) is 0.01, the weight average molecular weight (Mw) is 620,000, and the dispersity (Mw / Mn) is 11 Met.

(Production Example 2)
-Production of (meth) acrylic copolymer B-
In Production Example 1, the (meth) acrylic copolymer B solution was prepared in the same manner as in Production Example 1 except that the amount of the monomer used was changed as shown in Table 1 without using M-5300. Manufactured. In addition, the compounding quantity of the monomer shown in Table 1 represents the mass%. The acid value of (meth) acrylic copolymer B (shown as “resin B” in the table) is 0, the weight average molecular weight (Mw) is 610,000, and the dispersity (Mw / Mn) is 11. It was.

(Production Example 3)
-Production of (meth) acrylic copolymers C to G, J, K-
In Production Example 1, (meth) acrylic copolymers C to G, J, and K solutions were produced in the same manner as in Production Example 1 except that the blending amount was changed as shown in Table 1 below. Acid value and weight average molecular weight (Mw) of (meth) acrylic copolymers C to G, J, and K (represented in the table as “resin C” to “resin G”, “resin J”, and “resin K”, respectively) Table 1 shows the degree of dispersion (Mw / Mn).

(Production Example 4)
-Production of (meth) acrylic copolymer H-
In Production Example 1, (meth) acrylic copolymer H was used in the same manner as in Production Example 1, except that acrylic acid (AA) was used instead of M-5300, and the blending amount thereof was changed as shown in Table 1 below. A solution was prepared. Here, AA is acrylic acid. The acid value of (meth) acrylic copolymer H (shown as “resin H” in the table) is 0.1, the weight average molecular weight (Mw) is 610,000, and the dispersity (Mw / Mn) is 11 Met.

(Production Example 5)
-Production of (meth) acrylic copolymer I-
In Production Example 1, (meth) acrylic copolymer I was used in the same manner as in Production Example 1 except that the amount of the monomer used was changed as shown in Table 1 without using butyl acrylate (BA). A solution was prepared. The acid value of (meth) acrylic copolymer I (shown as “resin I” in the table) is 0.1, the weight average molecular weight (Mw) is 500,000, and the dispersity (Mw / Mn) is 9 Met.

Abbreviations in Table 1 are as follows.
(resin)
BA: n-butyl acrylate 2EHA: 2-ethylhexyl acrylate 4HBA: 4-hydroxybutyl acrylate M-5300: manufactured by Toagosei Co., Ltd., Aronix M-5300, ω-carboxy-polycaprolactone (n≈2) Monoacrylate / AA: Acrylic acid

<Example 1>
In a four-necked flask equipped with a stirring blade, a thermometer, a cooler, and a dropping funnel, the above-obtained (meth) acrylic copolymer A solution is 100 parts in terms of solid content, and SH3773M (Toray Dow Corning Co., Ltd., the side-chain polyether-modified silicone, 0.3 parts of a polyether-terminal hydroxyl groups), as an ionic solid N- hexyl pyridinium hexafluorophosphate (N- hexyl pyridinium-PF 6 _- ^a) 0. 1 part, 0.02 part of a cross-linking catalyst solution obtained by diluting dioctyltin laurate [trade name; ADK STAB OT-1; manufactured by ADEKA Co., Ltd.] 300 times with acetylacetone as a cross-linking catalyst was added to the flask. The mixture temperature was kept at 25 ° C. and mixed and stirred for 4.0 hours to mix the (meth) acrylic copolymer. To obtain a liquid.
To this, 3 parts of trade name: Desmodur N3300 [HMDI trimer type, solid content: 100% by mass; manufactured by Sumika Bayer Urethane Co., Ltd.] is added as a polyisocyanate compound as a cross-linking agent. A composition was obtained.
Using the obtained pressure-sensitive adhesive composition, a test film was prepared according to the following test film preparation method, and various physical property tests were performed. The obtained results are shown in Table 2.

(1) Production of test film Adhesive so that the coating amount after drying is 20 g / m ² on a polyethylene terephthalate (PET) film [trade name; Tetron G2; manufactured by Teijin Tetron Film Co., Ltd.] The composition was applied and dried at 100 ° C. for 60 seconds in a hot air circulating drier to form an adhesive layer, and then surface-treated with a silicone release agent, a polyethylene terephthalate (PET) film [trade name; film Bina 100E-0010NO23; manufactured by Fujimori Kogyo Co., Ltd.] so that the pressure-sensitive adhesive layer surface is in contact with each other, and pressed and bonded through a pressure nip roll, followed by curing for 5 days in an environment of 23 ° C. and 50% RH. A test film was obtained.

(2) Evaluation of contamination (bubble traces)
A polarizing plate was bonded to the front and back of a glass substrate (manufactured by Matsunami Glass Industry Co., Ltd., blue plate glass) with an acrylic pressure-sensitive adhesive so that the polarization axis was in a crossed Nicol state, to obtain a substrate with a polarizing plate. The acrylic pressure-sensitive adhesive to be used may be any pressure-sensitive adhesive as long as it does not peel off during the test and a certain degree of transparency is obtained.
The protective film was bonded by the adhesive composition used as evaluation object to the polarizing plate of a board | substrate with a polarizing plate. After 5 to 10 seconds, the protective film was peeled off from the adherend, and bonded again so that air bubbles entered immediately after. Thereafter, it was left in a dryer at 60 ° C. for 3 hours. Further, after standing for 30 minutes in an environment of 25 ° C. and 50% RH, the protective film was peeled off, and the traces of bubbles on the polarizing plate surface were visually confirmed under a xenon lamp fluorescent lamp (Polarion, NP1 type). Contamination was evaluated according to the evaluation criteria.
The anti-glare-treated polarizing plate (AG plate) [trade name: SQ-1852AP-AG6; manufactured by Sumitomo Chemical Co., Ltd.] and the anti-glare-treated polarizing plate (glare plate) [product] Name: SRDB31E; manufactured by Sumitomo Chemical Co., Ltd.].

~Evaluation criteria~
A: A bubble mark remains extremely thin, but there is no practical problem.
B: Bubble marks can be confirmed and cannot be put to practical use.
C: A level at which bubble marks can be clearly confirmed and cannot be put into practical use.

(3) Evaluation of peelability After the test film prepared in the above (1) was cut to 25 mm × 150 mm, the release paper was peeled off from the film piece, and the antiglare-treated polarizing plate [product] Name: SQ-1852AP-AG6; manufactured by Sumitomo Chemical Co., Ltd.] was used as a test sample.
This test sample was allowed to stand (conditioning treatment) for 24 hours in an environment of 23 ° C. and 50% RH. Thereafter, the adhesive force when the surface protective film was peeled from the polarizing plate in the long side (150 mm) direction along with the adhesive layer at a peeling angle of 180 ° and a peeling speed of 30 m / min was measured. According to the following evaluation criteria, the peelability was evaluated based on the adhesive force at the time of high-speed peeling.

~Evaluation criteria~
A: The adhesive strength was 0.6 N / 25 mm or less.
B: The adhesive strength exceeded 0.6 N / 25 mm and was 1.0 N / 25 mm or less.

(4) Evaluation of antistatic property -Surface resistance value-
The release film is peeled off from the test surface protective film prepared above, and the surface resistance value (Ω / □) of the surface of the exposed pressure-sensitive adhesive layer is measured using a surface resistance measuring device (Advantest Co., Ltd .: R12704 RESISTIVITY CHAMBER). Measured.

-Stripping voltage-
After the surface protective film for test prepared above was cut to 25 mm × 150 mm, the test piece of the test pressure-sensitive adhesive sheet was subjected to anti-glare treatment while peeling the release film using a desktop laminating machine. A test sample was prepared by pressure bonding to a polarizing plate [trade name; SQ-1852AP-AG6; manufactured by Sumitomo Chemical Co., Ltd.]. This test sample was allowed to stand for 24 hours under the conditions of 23 ° C. and 50% RH (conditioning treatment), and then peeled off under the conditions of peeling angle: 180 ° and peeling speed: 30 m / min (high-speed peeling conditions). The potential (kV) of the polarizing plate surface generated at this time was measured with a potential measuring device [KSD-0303 manufactured by Kasuga Denki Co., Ltd.] fixed at a predetermined position. The measurement was performed in an environment of 23 ° C. and 50% RH.

  Based on the measured values of the surface resistance value and the peeling voltage, the antistatic property was evaluated according to the following evaluation criteria.

~Evaluation criteria~
AA: The surface resistance value is less than 1.0E + 11 (Ω / □), and the absolute value of the peeling band voltage is less than 0.5 kV.
A: The surface resistance value is 1.0E + 11 (Ω / □) or more and less than 5.0E + 11 (Ω / □), and the absolute value of the peeling band voltage is less than 0.5 kV.
B: The surface resistance value is 5.0E + 11 (Ω / □) or more and less than 1.0E + 12 (Ω / □), and the absolute value of the peeling band voltage is less than 0.5 kV.
C: The surface resistance value is 1.0E + 12 (Ω / □) or more, or the absolute value of the peeling band voltage is 0.5 kV or more.

<Examples 2 to 26, Comparative Examples 1 to 8>
In Example 1, except that each component used for the preparation of the pressure-sensitive adhesive composition was changed as shown in Table 2, a pressure-sensitive adhesive composition was prepared in the same manner as in Example 1, and various types were similarly performed. A physical property test was conducted. The obtained results are shown in Table 2.

Abbreviations in Table 2 are as follows.
(Polysiloxane)
Siloxane A: SH3773M [Toray Dow Corning Co., Ltd., side chain polyether-modified silicone, polysiloxane compound represented by general formula (3), having a hydroxyl group at the terminal]
Siloxane B: SF8427 [manufactured by Toray Dow Corning Co., Ltd., both end polyether-modified silicone, having a hydroxyl group at the end]
Siloxane C: SH8400 [manufactured by Dow Corning Toray, side-chain polyether-modified silicone, having an acetoxy group at the terminal]
Siloxane D: KF-859 (Shin-Etsu Chemical Co., Ltd., dimethylpolysiloxane, having an amine group at the end)

(Ionic solid)
AS agent A: N-hexylpyridinium PF ^6- [ionic solid having hexylpyridinium ion as organic cation, melting point: 45 ° C.]
AS agent B: N-butyl-4-methylpyridinium PF ^6- [ionic solid having butyl-4-methylpyridinium ion as organic cation; melting point: 48 ° C.]
AS agent C: N-butyl-pyridinium PF ^6- [ionic solid having butylpyridinium ion as organic cation; melting point: 75 ° C.]
AS agent D: N-octyl-4-methylpyridinium FSI (ionic liquid having octylpyridinium as organic cation; melting point less than 25 ° C.)
AS agent E: LiF ₃ SO ₃ (LiTFS, alkali metal salt; melting point: 423 ° C.)

(Crosslinking agent)
Crosslinking agent A: N3300: Desmodur N3300 [hexamethylene diisocyanate trimer, manufactured by Sumika Bayer Urethane Co., Ltd.]
-Crosslinking agent B: MHG-80B (manufactured by Asahi Kasei Chemicals Corporation, HMDI-based crosslinking agent)

In Comparative Example 1, it can be seen that the (meth) acrylic copolymer having no acidic group and having an acid value of 0 is used, so that the contamination is poor. In the comparative example 2, since ionic solid whose melting | fusing point is less than 25 degreeC is used, it turns out that it is inferior to pollution property. In the comparative example 3, since the ionic solid which does not have an organic cation is used, it turns out that it is inferior to pollution property. In the comparative example 4, since content of an ionic solid exceeds 0.2 mass part, it turns out that it is inferior to pollution property. It can be seen that Comparative Example 5 is inferior in antistatic property because it does not contain an ionic solid. In Comparative Example 6, since the content of the dimethylpolysiloxane compound exceeds 1 part by mass, it can be seen that the antistatic property is poor. In Comparative Example 7, since a dimethylpolysiloxane compound having no hydroxyl group is used as a reactive group , it can be seen that the contamination is poor. In Comparative Example 8, since a dimethylpolysiloxane compound that is not polyether-modified is used, it can be seen that the antistatic property is poor.

  On the other hand, it can be seen that the film formed from the pressure-sensitive adhesive composition of the present invention has excellent antifouling properties and antistatic properties, and can be easily peeled off due to low adhesive strength at high-speed peeling.

Claims (5)

A (meth) acrylic copolymer having an acidic group and a hydroxyl group;
An ionic solid containing an organic cation and having a melting point of 25 ° C. or higher;
A polyether-modified dimethylpolysiloxane compound having a hydroxyl group as a reactive group;
A polyisocyanate compound as a crosslinking agent;
Including
The content of the ionic solid is 0.2 parts by mass or less with respect to 100 parts by mass of the (meth) acrylic copolymer,
Content of the said polyether modified dimethylpolysiloxane compound is an adhesive composition which is 1 mass part or less with respect to 100 mass parts of said (meth) acryl copolymers. Before SL weight ratio of the polyether-modified dimethylpolysiloxane compound to the crosslinking agent (polyether-modified dimethylpolysiloxane compound / crosslinking agent) is a 3/100 to 20/100, pressure-sensitive adhesive composition according to claim 1 . The pressure-sensitive adhesive composition according to claim 1 or 2, wherein an acid value of the (meth) acrylic copolymer is more than 0 and 1 or less. The pressure-sensitive adhesive composition according to any one of claims 1 to 3 , which is used for an optical member surface protective film. A substrate;
A pressure-sensitive adhesive layer provided on the base material and derived from the pressure-sensitive adhesive composition according to any one of claims 1 to 3 ,
An optical member surface protective film comprising: