KR102476434B1 - Pressure-sensitive adhesive composition, surface protective sheet and optical member - Google Patents

Abstract

(Problem) An adhesive composition capable of forming a surface protection sheet capable of suppressing generation of static electricity on an adherend when the surface protection sheet is peeled off from an adherend even in a low-temperature environment, the surface protection sheet, and the surface protection An optical member formed by sticking a sheet is provided.
(Solution) The pressure-sensitive adhesive composition of the present invention contains an onium salt having a melting point of -4°C or lower, and a polymer having a glass transition temperature of 0°C or lower as a base polymer, and the onium salt is a nitrogen-containing onium salt, It is characterized by being at least one selected from the group consisting of sulfur-containing onium salts and phosphorus-containing onium salts.
(selectivity) None

Description

Adhesive composition, surface protection sheet, and optical member {PRESSURE-SENSITIVE ADHESIVE COMPOSITION, SURFACE PROTECTIVE SHEET AND OPTICAL MEMBER}

The present invention relates to an adhesive composition, a surface protection sheet, and an optical member protected by the surface protection sheet.

The surface protective sheet formed from the pressure-sensitive adhesive composition of the present invention is used to protect the surface of optical members such as polarizing films, wave plates, retardation plates, optical compensation films, reflective sheets, and brightness enhancing films used in liquid crystal displays and the like.

In recent years, when transporting optical components and electronic components or mounting them on a printed circuit board, transporting the individual components in a state in which they are wrapped in a predetermined sheet or in a state in which an adhesive tape is applied is performed. Among them, surface protection sheets are particularly widely used in the field of optical/electronic components.

The surface protection sheet is generally bonded to an adherend (object to be protected) via an adhesive applied to the support film side, for the purpose of preventing scratches and contamination occurring during processing and transportation of the adherend. is used (Patent Document 1). For example, the panel of a liquid crystal display is formed by bonding optical members, such as a polarizing film and a wave plate, to a liquid crystal cell through an adhesive. These optical members are bonded together with a surface protection film via an adhesive, and scratches and stains generated during processing and conveyance of adherends are prevented. And this surface protection sheet is peeled off and removed at the stage which became unnecessary.

In general, surface protection sheets and optical members are made of plastic materials, so they have high electrical insulation properties, and static electricity is generated during friction or peeling. In particular, in a low-temperature environment, when the humidity is low and the surface protection sheet is peeled from the adherend (such as a polarizing film), the peeling band voltage tends to increase, and static electricity is likely to be generated when the surface protection sheet is peeled from the adherend. . For example, when the surface protective sheet is peeled from an optical member (polarizing film, etc.) of a liquid crystal display, the alignment of liquid crystal molecules is disturbed due to static electricity generated at the time of peeling. A display defect such as non-uniformity of white color in which a part of a white display occurs occurs, resulting in a problem that display inspection cannot be performed.

Japanese Unexamined Patent Publication No. 9-165460

Accordingly, an object of the present invention is to provide surface protection capable of suppressing generation of static electricity on an adherend when the surface protection sheet is peeled off from an adherend even in a low-temperature environment in order to solve the problems of conventional surface protection sheets. The present invention is to provide an adhesive composition capable of forming a sheet, the surface protection sheet, and an optical member formed by affixing the surface protection sheet.

That is, the pressure-sensitive adhesive composition of the present invention contains an onium salt having a melting point of -4°C or less, and a polymer having a glass transition temperature of 0°C or less as a base polymer, and the onium salt is a nitrogen-containing onium salt or a sulfur-containing onium salt. It is characterized by being at least one selected from the group consisting of a nium salt and a phosphorus-containing onium salt.

It is preferable that the adhesive composition of this invention contains the compound which has an alkylene oxide group.

In the pressure-sensitive adhesive composition of the present invention, it is preferable that the polymer having a glass transition temperature of 0°C or lower is a (meth)acrylic polymer having a hydroxyl group and/or a carboxyl group.

The surface protection sheet of the present invention preferably has a pressure-sensitive adhesive layer formed from the pressure-sensitive adhesive composition on one side of the support film.

The surface protective sheet of the present invention has an antistatic layer on a surface opposite to the pressure-sensitive adhesive layer formed on the support film, and the antistatic layer contains polyanilines and/or polythiophenes as a conductive polymer component. It is preferably formed from an antistatic agent composition containing

The optical member of the present invention is preferably protected by the surface protection sheet.

It is preferable that the optical member of this invention is a polarizing film containing a polarizer, and that the thickness of the said polarizer is 8 micrometers or less.

The surface protection sheet formed from the pressure-sensitive adhesive composition of the present invention is useful because it can suppress generation of static electricity on an adherend when the surface protection sheet is peeled off from an adherend even in a low-temperature environment.

1 is a schematic diagram of a potential measuring unit.

EMBODIMENT OF THE INVENTION Hereinafter, embodiment of this invention is described in detail.

<Overall structure of surface protection sheet>

The surface protection sheet of the present invention is generally referred to as a surface protection sheet, surface protection tape, surface protection film, etc. It is suitable as a surface protective sheet that protects the surface of an optical component during processing or conveyance of optical components). The pressure-sensitive adhesive layer in the surface protection sheet is typically formed continuously, but is not limited to this form, and may be formed in a regular or random pattern, such as dots or stripes, for example. do. In addition, the surface protection sheet disclosed herein may be in the form of a roll or sheet.

A typical configuration example of the surface protection sheet disclosed herein is one having a pressure-sensitive adhesive layer on one side of a support film (base material), and the pressure-sensitive adhesive layer formed on one side of the support film and the pressure-sensitive adhesive layer formed on the side opposite to the pressure-sensitive adhesive layer of the support film. What is equipped with an antistatic layer is mentioned. A surface protection sheet is used by sticking this pressure-sensitive adhesive layer to an adherend (a target to be protected, for example, the surface of an optical component such as a polarizing film). The surface protection sheet before use (ie, before sticking to an adherend) may be in a form in which the surface of the pressure-sensitive adhesive layer (the surface to be adhered to the adherend) is protected by a release liner in which at least the pressure-sensitive adhesive layer side is a release surface. Alternatively, when the surface protection sheet is wound into a roll shape, the pressure-sensitive adhesive layer may come into contact with the back surface (surface of the antistatic layer) of the support film and protect the surface thereof.

<Adhesive composition>

The pressure-sensitive adhesive composition of the present invention contains an onium salt having a melting point of -4°C or less, and a polymer having a glass transition temperature of 0°C or less as a base polymer, wherein the onium salt is a nitrogen-containing onium salt, a sulfur-containing onium salt, and at least one selected from the group consisting of phosphorus-containing onium salts. As the pressure-sensitive adhesive composition, as long as it contains the onium salt having a melting point of -4°C or less and a polymer having a glass transition temperature (Tg) of 0°C or less as a base polymer and can exhibit adhesiveness, it can be used without particular limitation. can For example, acrylic adhesives, urethane-based adhesives, polyester-based adhesives, synthetic rubber-based adhesives, natural rubber-based adhesives, silicone-based adhesives and the like using the base polymer may be used. Among them, an acrylic pressure-sensitive adhesive is a preferred embodiment in terms of being easy to control the adhesive properties.

In the present invention, the polymer having a glass transition temperature (Tg) of 0°C or lower is preferably a (meth)acrylic polymer, and more preferably a (meth)acrylic polymer having a hydroxyl group and/or a carboxyl group. . Preferable aspect becomes In addition, by using the (meth)acrylic polymer having the hydroxyl group and/or the carboxyl group, the hydroxyl group can easily control the crosslinking, and the carboxyl group can improve the shear force, Since the rise of the adhesive force by time passage can be prevented, it becomes a preferable aspect. In particular, by using the (meth)acrylic polymer having the above hydroxyl group and/or carboxyl group, the shear force of the pressure-sensitive adhesive (layer) is improved, thereby bonding the pressure-sensitive adhesive to the adherend to suppress curl based on the adherend. This is preferable because it is possible to suppress occurrence of slipping or shifting between the pressure-sensitive adhesive and the adherend (interface).

Further, in the present invention, a polymer having a glass transition temperature (Tg) of 0°C or lower is contained as the base polymer, but 100 mass% of the polymer having a glass transition temperature (Tg) of 0°C or lower is 100% by mass of the base polymer. It is a more preferable aspect that it is %. In addition, the (meth)acrylic polymer in the present invention refers to an acrylic polymer and/or a methacrylic polymer, and (meth)acrylate refers to an acrylate and/or methacrylate.

Moreover, it is preferable that the said (meth)acrylic-type polymer contains the said hydroxyl-group containing (meth)acrylic-type monomer as a monomer component. By using the above hydroxyl group-containing (meth)acrylic monomer, crosslinking of the pressure-sensitive adhesive composition can be easily controlled, and by extension, wettability due to flow can be improved, and the balance between the cohesive force and shear force of the pressure-sensitive adhesive (layer) can be easily controlled. . In addition, when an antistatic agent is added to an adhesive, unlike a carboxyl group or a sulfonate group that can generally act as a crosslinking site, a hydroxyl group has an appropriate interaction with an antistatic agent, such as an onium salt having a melting point of -4 ° C or less. For this reason, it can act suitably also in the surface of antistatic property.

In the present invention, it is preferable to contain 0.1 to 20% by mass of a hydroxyl group-containing (meth)acrylic monomer, more preferably 0.5 to 15, based on the total amount of monomer components constituting the (meth)acrylic polymer. % by mass, more preferably 0.75 to 13% by mass, and most preferably 1 to 10% by mass. When it is within the above range, the balance between the wettability of the pressure-sensitive adhesive composition and the cohesive force or shear force of the pressure-sensitive adhesive (layer) can be easily controlled, which is preferable. In addition, in order to express favorable charging characteristics with a smaller amount of the onium salt, a smaller amount of the hydroxyl group-containing (meth)acrylic monomer is effective.

Examples of the hydroxyl group-containing (meth)acrylic monomer include 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, 6-hydroxyhexyl (meth)acrylate, 8-hydroxyoctyl (meth)acrylate, 10-hydroxydecyl (meth)acrylate, 12-hydroxylauryl (meth)acrylate, (4-hydroxy Methyl cyclohexyl) methyl acrylate, N-methylol (meth) acrylamide, etc. are mentioned. Moreover, as said hydroxyl-group containing (meth)acrylic-type monomer, you may use independently and may use 2 or more types as a monomer component.

Moreover, it is preferable that the said (meth)acrylic-type polymer contains the said carboxyl group-containing (meth)acrylic-type monomer as a monomer component. By using the carboxyl group-containing (meth)acrylic monomer, the increase in the adhesive force of the surface protection sheet (pressure-sensitive adhesive layer) over time can be suppressed, and the re-peelability, adhesive force increase prevention property, and workability are excellent. , It is preferable because it is excellent in shear force as well as the cohesive force of the pressure-sensitive adhesive layer.

In the present invention, the carboxyl group-containing (meth)acrylic monomer is preferably contained in an amount of 0.001 to 0.5% by mass, more preferably 0.002 to 0.4% by mass, based on the total amount of the monomer components constituting the (meth)acrylic polymer. , more preferably from 0.003 to 0.3% by mass, even more preferably from 0.004 to 0.2% by mass, and most preferably from 0.005 to 0.1% by mass. When it is within the above range, an increase in adhesive force over time can be suppressed, and re-peelability, adhesive force increase prevention property, and workability are excellent. In addition, it is preferable because it is excellent in shear force as well as the cohesive force of the pressure-sensitive adhesive layer. In addition, when a large number of acidic functional groups such as carboxyl groups having a large polar action are present, when an onium salt having a melting point of -4 ° C. or less that can be used as an antistatic agent is blended, the acidic functional groups such as carboxyl groups and the onium salt etc. interact This is undesirable because there is a risk that ion conduction is hindered, the conduction efficiency is lowered, and sufficient antistatic properties cannot be obtained.

Examples of the carboxyl group-containing (meth)acrylic monomer include (meth)acrylic acid, carboxylethyl (meth)acrylate, carboxylpentyl (meth)acrylate, and 2-(meth)acryloyloxyethyl hexahydro. Phthalic acid, 2-(meth)acryloyloxypropylhexahydrophthalic acid, 2-(meth)acryloyloxyethylphthalic acid, 2-(meth)acryloyloxyethylsuccinic acid, 2-(meth)acryloyloxyethyl Maleic acid, carboxypolycaprolactone mono(meth)acrylate, 2-(meth)acryloyloxyethyl tetrahydrophthalic acid, etc. are mentioned. Moreover, as said carboxyl group-containing (meth)acrylic-type monomer, you may use independently and may use 2 or more types as a monomer component.

In the present invention, the (meth)acrylic polymer preferably uses a (meth)acrylic monomer having an alkyl group of 1 to 14 carbon atoms as a monomer component, more preferably an alkyl group of 4 to 14 carbon atoms. It is a (meth)acrylic monomer with As a (meth)acrylic-type monomer which has the said C1-C14 alkyl group, you may use independently and may use 2 or more types as a monomer component.

Specific examples of the (meth)acrylic monomer having an alkyl group of 1 to 14 carbon atoms include, for example, methyl (meth)acrylate, ethyl (meth)acrylate, n-butyl (meth)acrylate, and s-butyl (meth)acrylate, t-butyl (meth)acrylate, isobutyl (meth)acrylate, hexyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, n-octyl (meth)acrylate, iso Octyl(meth)acrylate, n-nonyl(meth)acrylate, isononyl(meth)acrylate, n-decyl(meth)acrylate, isodecyl(meth)acrylate, n-dodecyl(meth)acrylate , n-tridecyl (meth)acrylate, n-tetradecyl (meth)acrylate, etc. are mentioned.

Among them, hexyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, n-octyl (meth) acrylate, isooctyl (meth) acrylate, n-nonyl ( meth)acrylate, isononyl (meth)acrylate, n-decyl (meth)acrylate, isodecyl (meth)acrylate, n-dodecyl (meth)acrylate, n-tridecyl (meth)acrylate, (meth)acrylates having an alkyl group having 6 to 14 carbon atoms, such as n-tetradecyl (meth)acrylate, are exemplified as suitable ones. By using the (meth)acrylate having an alkyl group of 6 to 14 carbon atoms, it becomes easy to control the adhesive force to the adherend to a low level, and the re-peelability becomes excellent.

In the present invention, it is preferable to contain 50 to 99% by mass of the (meth)acrylic monomer having an alkyl group having 1 to 14 carbon atoms with respect to the total amount of monomer components constituting the (meth)acrylic polymer, more preferably It is preferably 60 to 98.8% by mass, more preferably 70 to 98.6% by mass, and most preferably 80 to 98.5% by mass. By being within the above range, the pressure-sensitive adhesive composition has moderate wettability and the cohesive force of the pressure-sensitive adhesive (layer) is also excellent, which is preferable.

In addition, as the other polymerizable monomer component, the glass transition temperature (Tg) is set to 0 ° C. or lower (usually -100 ° C. or higher) for the reason that the adhesion performance is easily balanced, and the Tg of the above-mentioned (meth)acrylic polymer or a polymerizable monomer for adjusting peelability can be used within a range that does not impair the effect of the present invention.

Polymerization properties other than the hydroxyl group-containing (meth)acrylic monomer, the carboxyl group-containing (meth)acrylic monomer, and the (meth)acrylic monomer having an alkyl group of 1 to 14 carbon atoms used in the (meth)acrylic polymer As a monomer, it can be used without being specifically limited as long as it is within the range which does not impair the characteristics of this invention. For example, components for improving cohesion and heat resistance such as cyano group-containing monomers, vinyl ester monomers, aromatic vinyl monomers, amide group-containing monomers, imide group-containing monomers, amino group-containing monomers, epoxy group-containing monomers, N-acryloylmorpholine , a component having a functional group that acts as an adhesive (adhesive) force improving agent such as vinyl ether monomer or a crosslinking origin, and a peel force adjusting component such as an alkylene oxide group-containing monomer can be appropriately used. These polymerizable monomers may be used alone or in combination of two or more.

Examples of the cyano group-containing monomer include acrylonitrile and methacrylonitrile.

Examples of the vinyl ester monomer include vinyl acetate, vinyl propionate, and vinyl laurate.

Examples of the aromatic vinyl monomer include styrene, chlorostyrene, chloromethylstyrene, α-methylstyrene, and other substituted styrene.

Examples of the amide group-containing monomer include acrylamide, methacrylamide, diethylacrylamide, N-vinylpyrrolidone, N,N-dimethylacrylamide, N,N-dimethylmethacrylamide, N, N-diethylacrylamide, N,N-diethylmethacrylamide, N,N'-methylenebisacrylamide, N,N-dimethylaminopropylacrylamide, N,N-dimethylaminopropylmethacrylamide, diacetone Acrylamide, N-methyl(meth)acrylamide, N-isopropyl(meth)acrylamide, N-t-butyl(meth)acrylamide, N,N-dipropylacrylamide, N,N-diisopropyl(meth) Acrylamide, N,N-dibutyl (meth)acrylamide, N-ethyl-N-methyl (meth)acrylamide, N-methyl-N-propyl (meth)acrylamide, N-methyl-N-isopropyl ( Meth)acrylamide, N-methylolacrylamide, diacetoneacrylamide, N-vinylacetamide, N,N'-methylenebisacrylamide, N,N-diethylaminopropyl (meth)acrylamide, N,N -Dipropylaminopropyl (meth)acrylamide, N,N-diisopropylaminopropyl (meth)acrylamide, N-ethyl-N-methylaminopropyl (meth)acrylamide, N-methyl-N-propylaminopropyl (meth)acrylamide, N-methyl-N-isopropylaminopropyl (meth)acrylamide, N-vinylacetamide, N-vinyl-N-methylacetamide, N-methoxymethyl (meth)acrylamide, N -Ethoxyethyl (meth)acrylamide, N-butoxymethyl (meth)acrylamide, N-vinyl caprolactam, etc. are mentioned.

As said imide group containing monomer, cyclohexyl maleimide, isopropyl maleimide, N-cyclohexyl maleimide, itaconimide etc. are mentioned, for example.

Examples of the amino group-containing monomer include aminoethyl (meth)acrylate, N,N-dimethylaminomethyl (meth)acrylate, N,N-dimethylaminoethyl (meth)acrylate, and N,N-dimethyl Aminopropyl (meth)acrylate, N,N-dimethylaminoisopropyl (meth)acrylate, N,N-dimethylaminobutyl (meth)acrylate, N,N-diethylaminomethyl (meth)acrylate, N ,N-diethylaminoethyl (meth)acrylate, N-ethyl-N-methylaminoethyl (meth)acrylate, N-methyl-N-propylaminoethyl (meth)acrylate, N-methyl-N-iso Propylaminoethyl (meth)acrylate, N,N-dibutylaminoethyl (meth)acrylate, t-butylaminoethyl (meth)acrylate, etc. are mentioned.

Examples of the epoxy group-containing monomer include glycidyl (meth)acrylate, methyl glycidyl (meth)acrylate, and allyl glycidyl ether.

As said vinyl ether monomer, methyl vinyl ether, ethyl vinyl ether, isobutyl vinyl ether etc. are mentioned, for example.

Examples of the alkylene oxide group-containing monomer include methoxy-polyethylene glycol (meth)acrylate type such as methoxy-diethylene glycol (meth)acrylate and methoxy-triethylene glycol (meth)acrylate. , Ethoxy-diethylene glycol (meth) acrylate, ethoxy-polyethylene glycol (meth) acrylate type such as ethoxy-triethylene glycol (meth) acrylate, butoxy-diethylene glycol (meth) acrylate, butoxy-polyethylene glycol (meth)acrylate type such as butoxy-triethylene glycol (meth)acrylate, phenoxy-diethylene glycol (meth)acrylate, phenoxy-triethylene glycol (meth)acrylate, etc. Phenoxy-polyethylene glycol (meth)acrylate type, 2-ethylhexyl-polyethylene glycol (meth)acrylate type, nonylphenol-polyethylene glycol (meth)acrylate type, methoxy-dipropylene glycol (meth)acrylate type, etc. A methoxy-polypropylene glycol (meth)acrylate type|mold etc. are mentioned.

In the present invention, other polymerizable monomers other than the hydroxyl group-containing (meth)acrylic monomer, the carboxyl group-containing (meth)acrylic monomer, and the (meth)acrylic monomer having an alkyl group having 1 to 14 carbon atoms, the above ( It is preferably 0 to 40% by mass, more preferably 0 to 30% by mass, in the total amount of monomer components constituting the meth)acrylic polymer (all monomer components). By using the other polymerizable monomer within the above range, good interaction with an onium salt having a melting point of -4°C or less used as an antistatic agent, and good releasability can be appropriately adjusted.

The (meth)acrylic polymer has a weight average molecular weight (Mw) of preferably 100,000 to 5,000,000, more preferably 200,000 to 4,000,000, still more preferably 300,000 to 3,000,000, and most preferably 400,000 to 400,000. 700,000. When Mw is smaller than 100,000, the cohesive force of the pressure-sensitive adhesive layer obtained is reduced, so that adhesive residue tends to occur. On the other hand, when the Mw exceeds 5,000,000, the fluidity of the polymer is lowered and wetting to the adherend (for example, a polarizing film as an optical member) becomes insufficient, and the adhesive of the adherend and the surface protection sheet (adhesive sheet) It tends to cause swelling occurring between the layers (layers of the pressure-sensitive adhesive composition). In addition, Mw means what was obtained by measuring by the gel permeation chromatography method (GPC).

Further, the base polymer contains a polymer having a glass transition temperature (Tg) of 0°C or less (eg, the (meth)acrylic polymer), and the Tg of the polymer is preferably -10°C or less, and It is preferably -40°C or lower, more preferably -60°C or lower (usually -100°C or higher). When the Tg is higher than 0°C, the polymer does not flow well, and, for example, wetting to the adherend (for example, a polarizing film as an optical member) becomes insufficient, and the adherend and the pressure-sensitive adhesive layer (pressure-sensitive adhesive composition layer) tends to cause swelling that occurs between Moreover, by setting Tg to 0°C or less, it becomes easy to obtain an adhesive composition excellent in wettability to an adherend and easy peelability. In addition, the Tg of the polymer having a glass transition temperature (Tg) of 0°C or less (for example, the (meth)acrylic polymer) can be adjusted within the above range by appropriately changing the monomer component and composition ratio to be used.

The polymerization method of the polymer having a glass transition temperature (Tg) of 0°C or lower (eg, the (meth)acrylic polymer) used in the present invention is not particularly limited, but is solution polymerization, emulsion polymerization, or bulk polymerization. ) Although polymerization can be carried out by a known method such as polymerization or suspension polymerization, solution polymerization is a more preferable mode, particularly from the viewpoint of workability and properties such as low contamination of adherends. Moreover, any of a random copolymer, a block copolymer, an alternating copolymer, a graft copolymer, etc. may be sufficient as the polymer obtained.

The pressure-sensitive adhesive composition of the present invention contains an onium salt having a melting point of -4°C or less, and the onium salt is at least one selected from the group consisting of nitrogen-containing onium salts, sulfur-containing onium salts, and phosphorus-containing onium salts. to be characterized By using an onium salt having a melting point of -4°C or less (preferably -10°C or less, more preferably -70°C or more and -20°C or less), the effect of suppressing peeling and charging in a low-temperature environment is increased, which is a preferred embodiment. . Further, when the onium salt contains an onium cation having at least one alkyl group having 8 or more carbon atoms, both shear characteristics and charging characteristics can be achieved, which is preferable.

The onium salt having a melting point of -4°C or less is at least one selected from the group consisting of nitrogen-containing onium salts, sulfur-containing onium salts, and phosphorus-containing onium salts, and nitrogen-containing onium salts, sulfur-containing onium salts, and phosphorus-containing onium salts. is a salt composed of a cation component composed of a nitrogen-containing onium ion, a sulfur-containing onium ion, and a phosphorus-containing onium ion, respectively, and an anion component described later.

Examples of the nitrogen-containing onium ion include 1-ethylpyridinium cation, 1-butylpyridinium cation, 1-hexylpyridinium cation, 1-butyl-3-methylpyridinium cation, 1 -Butyl-4-methylpyridinium cation, 1-hexyl-3-methylpyridinium cation, 1-butyl-3,4-dimethylpyridinium cation, 1,1-dimethylpyrrolidinium cation, 1- Ethyl-1-methylpyrrolidinium cation, 1-methyl-1-propylpyrrolidinium cation, 1-methyl-1-butylpyrrolidinium cation, 1-methyl-1-pentylpyrrolidinium cation, 1-methyl-1-hexylpyrrolidinium cation, 1-methyl-1-heptylpyrrolidinium cation, 1-ethyl-1-propylpyrrolidinium cation, 1-ethyl-1-butylpyrrolidinium cation One, 1-ethyl-1-pentylpyrrolidinium cation, 1-ethyl-1-hexylpyrrolidinium cation, 1-ethyl-1-heptylpyrrolidinium cation, 1,1-dipropylpyrrolidinium Cation, 1-propyl-1-butylpyrrolidinium cation, 1,1-dibutylpyrrolidinium cation, pyrrolidinium-2-one cation, 1-propylpiperidinium cation, 1-pentyl Piperidinium cation, 1,1-dimethylpiperidinium cation, 1-methyl-1-ethylpiperidinium cation, 1-methyl-1-propylpiperidinium cation, 1-methyl-1-butyl Piperidinium cation, 1-methyl-1-pentylpiperidinium cation, 1-methyl-1-hexylpiperidinium cation, 1-methyl-1-heptylpiperidinium cation, 1-ethyl-1 -Propylpiperidinium cation, 1-ethyl-1-butylpiperidinium cation, 1-ethyl-1-pentylpiperidinium cation, 1-ethyl-1-hexylpiperidinium cation, 1-ethyl -1-heptylpiperidinium cation, 1,1-dipropylpiperidinium cation, 1-propyl-1-butylpiperidinium cation, 1,1-dibutylpiperidinium cation, 2-methyl -1-pyrroline cation, 1-ethyl-2-phenylindole cation, 1,2-dimethylindole cation, 1-ethylcarbazole cation, N-ethyl-N-methylmorpholinium cation, 1 ,3-dimethylimidazolium cation, 1,3-diethylimidazolium cation, 1-ethyl-3-methylimidazolium cation, 1-butyl-3-methylimidazolium cation, 1- Hexyl-3-methylimidazolium cation, 1-octyl-3-methylimidazolium cation, 1-decyl-3-methylimidazolium cation Thione, 1-dodecyl-3-methylimidazolium cation, 1-tetradecyl-3-methylimidazolium cation, 1,2-dimethyl-3-propylimidazolium cation, 1-ethyl-2 ,3-dimethylimidazolium cation, 1-butyl-2,3-dimethylimidazolium cation, 1-hexyl-2,3-dimethylimidazolium cation, 1-(2-methoxyethyl)- 3-methylimidazolium cation, 1,3-dimethyl-1,4,5,6-tetrahydropyrimidinium cation, 1,2,3-trimethyl-1,4,5,6-tetrahydropyrimidinium cation Medium cation, 1,2,3,4-tetramethyl-1,4,5,6-tetrahydropyrimidinium cation, 1,2,3,5-tetramethyl-1,4,5,6 -Tetrahydropyrimidinium cation, 1,3-dimethyl-1,4-dihydropyrimidinium cation, 1,3-dimethyl-1,6-dihydropyrimidinium cation, 1,2,3 -trimethyl-1,4-dihydropyrimidinium cation, 1,2,3-trimethyl-1,6-dihydropyrimidinium cation, 1,2,3,4-tetramethyl-1,4- Dihydropyrimidinium cation, 1,2,3,4-tetramethyl-1,6-dihydropyrimidinium cation, 1-methylpyrazolium cation, 3-methylpyrazolium cation, 1-ethyl -2-methylpyrazolinium cation, 1-ethyl-2,3,5-trimethylpyrazolium cation, 1-propyl-2,3,5-trimethylpyrazolium cation, 1-butyl-2,3, 5-trimethylpyrazolium cation, 1-ethyl-2,3,5-trimethylpyrazolinium cation, 1-propyl-2,3,5-trimethylpyrazolinium cation, 1-butyl-2,3, 5-trimethylpyrazolinium cation, tetramethylammonium cation, tetraethylammonium cation, tetrabutylammonium cation, tetrapentylammonium cation, tetrahexylammonium cation, tetraheptylammonium cation, triethylmethylammonium cation one, tributylethylammonium cation, trimethyldecylammonium cation, N,N-diethyl-N-methyl-N-(2-methoxyethyl)ammonium cation, glycidyltrimethylammonium cation, diallyldimethyl Ammonium cation, N,N-dimethyl-N-ethyl-N-propylammonium cation, N,N-dimethyl-N-ethyl-N-butylammonium cation, N,N-dimethyl-N-ethyl-N- Pentylammonium cation, N,N-dimethyl-N-ethyl-N-hexylammo nium cation, N,N-dimethyl-N-ethyl-N-heptylammonium cation, N,N-dimethyl-N-ethyl-N-nonylammonium cation, N,N-dimethyl-N,N-dipropyl Ammonium cation, N,N-diethyl-N-propyl-N-butylammonium cation, N,N-dimethyl-N-propyl-N-pentylammonium cation, N,N-dimethyl-N-propyl-N -Hexylammonium cation, N,N-dimethyl-N-propyl-N-heptylammonium cation, N,N-dimethyl-N-butyl-N-hexylammonium cation, N,N-diethyl-N-butyl -N-heptylammonium cation, N,N-dimethyl-N-pentyl-N-hexylammonium cation, N,N-dimethyl-N,N-dihexylammonium cation, trimethylheptylammonium cation, N,N -Diethyl-N-methyl-N-propylammonium cation, N,N-diethyl-N-methyl-N-pentylammonium cation, N,N-diethyl-N-methyl-N-heptylammonium cation , N,N-diethyl-N-propyl-N-pentylammonium cation, triethylpropylammonium cation, triethylpentylammonium cation, triethylheptylammonium cation, N,N-dipropyl-N-methyl -N-ethylammonium cation, N,N-dipropyl-N-methyl-N-pentylammonium cation, N,N-dipropyl-N-butyl-N-hexylammonium cation, N,N-dipropyl -N,N-dihexylammonium cation, N,N-dibutyl-N-methyl-N-pentylammonium cation, N,N-dibutyl-N-methyl-N-hexylammonium cation, trioctylmethyl Ammonium cation, N-methyl-N-ethyl-N-propyl-N-pentylammonium cation, etc. are mentioned.

Examples of the sulfur-containing onium ion include diethylmethylsulfonium cation, dibutylethylsulfonium cation, dimethyldecylsulfonium cation, and triethylsulfonium cation.

Examples of the phosphorus-containing onium ion include trimethyldecylphosphonium cation, triethylmethylphosphonium cation, triethylpentylphosphonium cation, triethyloctylphosphonium cation, tributylmethylphosphonium cation, Tributylethylphosphonium cation, tributyloctylphosphonium cation, tributyldodecylphosphonium cation, tributyltetradecylphosphonium cation, trihexyltetradecylphosphonium cation, tetrabutylphosphonium cation, etc. can be heard

On the other hand, the anionic component is not particularly limited as long as it satisfies the onium salt having a melting point of -4°C or lower, and examples thereof include Cl ^- , Br ^- , I ^- , AlCl ₄ ^- , Al ₂ Cl ₇ ^- , BF ₄ ^- , PF ₆ ^- , SCN ^- , ClO ₄ ^- , NO ₃ ^- , CH ₃ COO ^- , CF ₃ COO ^- , CH ₃ SO ₃ - , CF ₃ SO ₃ ^{- ,} C ₄ F ₉ SO ₃ ^- , (CF ₃ SO ₂ ) ₂ N ^- , (C ₂ F ₅ SO ₂ ) ₂ N ^- , (C ₃ F ₇ SO ₂ ) ₂ N ^- , (C ₄ F ₉ SO ₂ ) ₂ N ^- , (CF ₃ SO ₂ ) ₃ C ^- , AsF ₆ ^- , SbF ₆ ^- , NbF ₆ ^- , TaF ₆ ^- , HF ₂ ^- , (CN) ₂ N ^- , C ₄ F ₉ SO ₃ ^- , (C ₂ F ₅ SO ₂ ) ₂ N ^- , C ₃ F ₇ COO ^- , (CF ₃ SO ₂ )(CF ₃ CO)N ^- , C ₉ H ₁₉ COO ^- , (CH ₃ ) ₂ PO ₄ ^- , (C ₂ H ₅ ) ₂ PO ₄ ^- , C ₂ H ₅ OSO ₃ ^- , C ₆ H ₁₃ OSO ₃ ^- , C ₈ H ₁₇ OSO ₃ ^- , CH ₃ (OCH ₄ ) ₂ OSO ₃ ^- , C ₆ H ₄ (CH ₃ )SO ₃ ^- , (C ₂ F ₅ ) ₃ PF ₃ ^- , CH ₃ CH(OH)COO ^- , and (FSO ₂ ) ₂ N ^- are used.

Moreover, as an anion component, the anion etc. represented by the following formula can also be used.

[Formula 1]

In addition, as an anion component, especially, an anion component containing a fluorine atom is preferably used because an onium salt with a low melting point is obtained.

As a specific example of the onium salt having a melting point of -4 ° C or less used in the present invention, it is appropriately selected and used from a combination of the cation component and the anionic component, for example, 1-butylpyridinium tetrafluoroborate, 1-hexylpyridinium tetrafluoroborate, 1-ethyl-3-methylpyridinium perfluorobutanesulfonate, 1-ethyl-3-methylpyridinium ethyl sulfate, 1-ethyl-3-methylpyridinium bis (fluorosulfonyl)imide, 1-methyl-1-butylpyrrolidinium bis(trifluoromethanesulfonyl)imide, 1-methyl-1-propylpyrrolidinium bisfluorosulfonylimide, 1 -Methyl-1-butylpyrrolidinium bis(trifluoromethanesulfonyl)imide, 1-methyl-1-butylpyrrolidinium tris(pentafluoroethyl)trifluorophosphate, 1-methoxyethyl-1 -Methylpyrrolidinium bis(trifluoromethanesulfonyl)imide, 1-methyl-1-ethylpiperidiniumbis(trifluoromethanesulfonyl)imide, 1-ethyl-3-methylpiperidiniumethyl Sulfate, 1-methoxyethyl-1-methylpiperidinium bis(trifluoromethanesulfonyl)imide, 1-methoxyethyl-1-methylpiperidinium tris(pentafluoroethyl)trifluorophosphate , 1-methyl-3-octylimidazolium bromide, 1-ethyl-3-methylimidazolium trifluoromethanesulfonate, 1-ethyl-3-methylimidazolium trifluoroacetate, 1-ethyl-3 -Methylimidazolium bis(fluorosulfonyl)imide, 1-ethyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide, 1-ethyl-3-methylimidazolium dicyanamide , 1-ethyl-3-methylimidazolium ethyl sulfate, 1-ethyl-3-methylimidazolium octyl sulfate, 1-ethyl-3-methylimidazolium thiocyanate, 1-butyl-3-methyl Imidazolium tetrafluoroborate, 1-butyl-3-methylimidazolium trifluoroacetate, 1-butyl-3-methylimidazolium bis(fluorosulfonyl)imide, 1-butyl-3-methyl Imidazolium tricyanomethane, 1-butyl-3-methylimidazolium dicyanamide, 1-hexyl-3-methylimidazolium bromide, 1-hexyl-3-methylimidazolium chloride, 1-hexyl-3 -Methylimidazolium tetrafluoroborate, 1-hexyl-3-methylimidazolium hexafluorophosphate, 1-hexyl-3-methylimidazolium bis(fluorosulfonyl)imide, 1 -Hexyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide, 1-octyl-3-methylimidazolium chloride, 1-octyl-3-methylimidazolium bromide, 1-octyl-3 -Methylimidazolium tetrafluoroborate, 1-octyl-3-methylimidazolium hexafluorophosphate, 1-octyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide, 1-dodecyl Syl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide, 1,3-dimethylimidazolium dimethylphosphate, 1,3-diallylimidazolium bromide, 1,3-diallylimida Zolium tetrafluoroborate, 1-allyl-3-butylimidazolium bis(trifluoromethanesulfonyl)imide, ethyl-dimethyl-propylammonium bis(trifluoromethanesulfonyl)imide, trioctylmethylammonium Bis(trifluoromethanesulfonyl)imide, 1-methoxyethyl-1-methylmorpholiniumammonium bis(trifluoromethanesulfonyl)imide, ethyl-dimethyl-(2-methoxyethyl)ammonium tris (pentafluoroethyl)trifluorophosphate, triethyloctylphosphonium bis(trifluoromethanesulfonyl)imide, trihexyltetradecylphosphoniumbis(trifluoromethanesulfonyl)imide, and the like. have.

The content of the onium salt is preferably 0.1 to 10 parts by mass, more preferably 0.1 to 5 parts by mass, still more preferably 0.2 to 3 parts by mass, and most preferably 0.3 to 1.5 parts by mass with respect to 100 parts by mass of the base polymer. do. If it exists in the said range, since it is easy to achieve both antistatic property and low contamination property, it is preferable.

It is preferable that the adhesive composition of this invention contains the compound which has an alkylene oxide group. By using the compound having an alkylene oxide group, it is possible to obtain an adhesive composition excellent in wettability to an adherend, and it becomes possible to suppress generation of static electricity efficiently.

Specific examples of the compound having an alkylene oxide group include, for example, polyoxyalkylene alkylamines, polyoxyalkylene diamines, polyoxyalkylene fatty acid esters, polyoxyalkylene sorbitan fatty acid esters, and polyoxyalkylenes. Nonionic surfactants such as alkylphenyl ether, polyoxyalkylene alkyl ether, polyoxyalkylene alkyl allyl ether, and polyoxyalkylene alkyl phenyl allyl ether; polyoxyalkylene alkyl ether sulfuric ester salt, polyoxyalkylene alkyl ether Anionic surfactants such as phosphoric acid ester salts, polyoxyalkylene alkylphenyl ether sulfuric acid ester salts, and polyoxyalkylene alkylphenyl ether phosphoric acid ester salts; Other caty groups having a polyalkylene oxide group (polyalkylene oxide chain) Ionic surfactants or zwitterionic surfactants, polyether compounds having a polyalkylene oxide group (including derivatives thereof), polyester compounds having a polyalkylene oxide group (including derivatives thereof), polyalkylene oxides group-containing acrylic compounds (and derivatives thereof are included); and the like. Further, an alkylene oxide group-containing monomer may be used as a compound having an alkylene oxide group, together with the base polymer (eg, the (meth)acrylic polymer). The compound having the said alkylene oxide group may be used independently, and may be used in combination of 2 or more type.

Specific examples of the polyether compound having an alkylene oxide group include polypropylene glycol (PPG)-polyethylene glycol (PEG) block copolymers, PPG-PEG-PPG block copolymers, and PEG-PPG-PEG block copolymers. A synthesis etc. are mentioned. Derivatives of the polyether compound having an alkylene oxide group include compounds containing an oxypropylene group etherified at the terminal (PPG monoalkyl ether, PEG-PPG monoalkyl ether, etc.), compounds containing an oxypropylene group acetylated at the terminal ( terminal acetylated PPG, etc.); and the like.

Moreover, as a specific example of the acrylic compound which has the said alkylene oxide group, the (meth)acrylate polymer which has an oxyalkylene group is mentioned. As the oxyalkylene group, the number of added moles of the oxyalkylene unit is preferably 1 to 50, more preferably 2 to 30, and even more preferably 2 to 20 from the viewpoint of coordination with the onium salt or the like as an antistatic agent do. Moreover, the terminal of the said oxyalkylene group may be in the state of being a hydroxyl group, or substituted with an alkyl group, a phenyl group, etc.

The (meth)acrylate polymer having an oxyalkylene group is preferably a polymer containing an alkylene oxide (meth)acrylate as a monomer component (monomer unit), and as a specific example of the alkylene oxide (meth)acrylate includes ethylene glycol group-containing (meth)acrylates, for example, methoxy-diethylene glycol (meth)acrylate, methoxy-polyethylene glycol such as methoxy-triethylene glycol (meth)acrylate (meth)acrylate type, ethoxy-diethylene glycol (meth)acrylate, ethoxy-polyethylene glycol (meth)acrylate type such as ethoxy-triethylene glycol (meth)acrylate, butoxy-diethylene glycol (meth)acrylate, butoxy-polyethylene glycol (meth)acrylate type such as butoxy-triethylene glycol (meth)acrylate, phenoxy-diethylene glycol (meth)acrylate, phenoxy-triethylene glycol ( Phenoxy-polyethylene glycol (meth)acrylate type such as meth)acrylate, 2-ethylhexyl-polyethylene glycol (meth)acrylate, nonylphenol-polyethylene glycol (meth)acrylate type, methoxy-dipropylene glycol ( Methoxy-polypropylene glycol (meth)acrylate types, such as meth)acrylate, etc. are mentioned.

Moreover, as said monomer component, other monomer components other than the said (meth)acrylic-acid alkylene oxide can be used. Specific examples of other monomer components include methyl (meth)acrylate, ethyl (meth)acrylate, n-butyl (meth)acrylate, s-butyl (meth)acrylate, t-butyl (meth)acrylate, Isobutyl (meth)acrylate, hexyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, n-octyl (meth)acrylate, isooctyl (meth)acrylate, n-nonyl (meth)acrylate , isononyl(meth)acrylate, n-decyl(meth)acrylate, isodecyl(meth)acrylate, n-dodecyl(meth)acrylate, n-tridecyl(meth)acrylate, n-tetradecyl Acrylates and/or methacrylates having an alkyl group having 1 to 14 carbon atoms, such as (meth)acrylate, are exemplified.

In addition, as other monomer components other than the above-mentioned (meth)acrylic acid alkylene oxide, carboxyl group-containing (meth)acrylates, phosphoric acid group-containing (meth)acrylates, cyano group-containing (meth)acrylates, vinyl esters, aromatic vinyl compounds , acid anhydride group-containing (meth)acrylate, hydroxyl group-containing (meth)acrylate, amide group-containing (meth)acrylate, amino group-containing (meth)acrylate, epoxy group-containing (meth)acrylate, N-acrylo It is also possible to use ilmorpholine, vinyl ether, etc. suitably.

As a preferable aspect, the compound having an alkylene oxide group is a compound having a (poly)ethylene oxide group at least in part. By blending the compound having the above (poly)ethylene oxide group, the compatibility between the base polymer (for example, the above (meth)acrylic polymer) and the antistatic agent (antistatic component) is improved, and the bleed to the adherend is suitably It is suppressed, and a low staining adhesive composition is obtained. Especially, when a block copolymer of PPG-PEG-PPG is used, an adhesive composition excellent in low staining property is obtained. As the (poly) ethylene oxide group-containing compound, the mass of the (poly) ethylene oxide group in the entire compound is preferably 5 to 90% by mass, more preferably 5 to 85% by mass, still more preferably It is 10-70 mass %, Most preferably, it is 20-50 mass %.

As the molecular weight of the compound having an alkylene oxide group, the number average molecular weight (Mn) is preferably less than 100000, more preferably 200 to 50000, still more preferably 500 to 30000, and particularly preferably 1000 to 10000 do. When Mn is 100000 or more, the compatibility with the base polymer (for example, the (meth)acrylic polymer) decreases, and the pressure-sensitive adhesive layer tends to whiten. If Mn is too small than 200, contamination by the compound having an alkylene oxide group may easily occur. In addition, here, Mn means the value of polystyrene conversion obtained by the gel permeation chromatography method (GPC).

In addition, specific examples of commercially available compounds having an alkylene oxide group include, for example, Adeka Pluronic 17R-4, Adeka Pluronic 25R-1, and Adeka Pluronic 25R-2 (above, ADEKA Inc.), Emulgen 120 (above, manufactured by Kao Corp.), and the like.

In the present invention, it is preferable that the compound having an alkylene oxide group is an organopolysiloxane having an alkylene oxide group. By using the organopolysiloxane, the surface free energy on the surface of the pressure-sensitive adhesive decreases, and it is estimated that light peeling at the time of high-speed peeling is realized.

As the organopolysiloxane, any known organopolysiloxane having an alkylene oxide group can be suitably used. KF-6004, KF-889, KF-351A, KF-352A, KF-353, KF-354L, KF-355A, KF-615A, KF-945, KF-640, KF-642, KF-643, KF- 6022, X-22-6191, X-22-4515, KF-6011, KF-6012, KF-6015, KF-6017, X-22-2516 (above, manufactured by Shin-Etsu Chemical Co., Ltd.), BY16-201, SF8427, SF8428, FZ-2162, SH3749, FZ-77, L-7001, FZ-2104, FZ-2110, L-7002, FZ-2122, FZ-2164, FZ-2203, FZ-7001, SH8400, SH8700, SF8410, SF8422 (above, manufactured by Toray Dow Corning), IM22 (above, manufactured by Asahi Kasei Wacker Co., Ltd.), TSF-4440, TSF-4441, TSF-4445, TSF-4450, TSF-4446, TSF-4452, TSF-4460 (above, manufactured by Momentive Performance Materials), BYK-333, BYK-307, BYK-377, BYK-UV3500, BYK-UV3570 (above, manufactured by Big Chemie Japan), and the like. These may be used independently, and may mix and use 2 or more types.

As for the organopolysiloxane used in the present invention, the HLB (Hydrophile-Lipophile Balance) value is preferably 1 to 16, more preferably 3 to 14. If the HLB value is out of the above range, contamination of adherends deteriorates, which is not preferable.

The content of the compound having an alkylene oxide group relative to 100 parts by mass of the base polymer is preferably from 0.01 to 5 parts by mass, more preferably from 0.03 to 3 parts by mass, still more preferably from 0.05 to 2 parts by mass. and most preferably 0.1 to 1 part by mass. If it exists within the said range, since coexistence of antistatic property and easy-peelability (repeelability) is easy to do, it is preferable. In addition, when the content is small, the effect of preventing bleeding of the antistatic agent (antistatic component) is reduced, and when the content is high, contamination by the compound itself having an alkylene oxide group tends to occur, which is preferable. don't

The pressure-sensitive adhesive composition of the present invention can also contain a fluorine-containing oligomer having a weight average molecular weight (Mw) of 3500 or more. By using the fluorine-containing oligomer, the chargeability of the adhesive itself is controlled, and even when applied to an optical member subjected to various surface treatments (hard coat treatment, antiglare treatment, low reflection treatment, etc.), it is possible to stably and efficiently generate static electricity. suppression becomes possible.

Examples of the fluorine-containing compound include a compound having a fluoroaliphatic hydrocarbon skeleton, a fluorine-containing organic compound obtained by copolymerizing an organic compound and a fluorine compound, and a fluorine-containing compound containing an organic compound. As a specific example of the said fluorine-containing oligomer, the trade name of a commercial item is Megafac F-251, F-253, F-281, F-410, F-430, F-444, F-477, F, for example. -510, F-511, F-551, F-552, F-553, F-554, F-555, F-556, F-557, F-558, F-559, F-560, F-561 , F-562, F-563, F-565, F-568, F-569, F-570, F-571, F-572 (above, manufactured by DIC), Suplon S-611, S-651, S-386 (above, manufactured by AGC Semichemical Co., Ltd.), Progent 610FM, 710FL, 710FM, 710FS, 730FL, 730LM (above, manufactured by Neos Co., Ltd.), and the like. These compounds may be used independently, and may mix and use 2 or more types.

The weight average molecular weight (Mw) of the fluorine-containing oligomer is preferably 3500 or more, more preferably 5000 or more, still more preferably 10000 or more, and most preferably 20000 or more. When the weight average molecular weight of the fluorine-containing oligomer is 3500 or more, compatibility with the pressure-sensitive adhesive is balanced, and it becomes possible to appropriately segregate on the surface of the pressure-sensitive adhesive. In addition, when the weight average molecular weight is 20000 or more, the generation of air bubbles at the time of mixing the pressure-sensitive adhesive can be suppressed and the appearance after application of the pressure-sensitive adhesive is excellent, so it is preferable.

The content of the fluorine-containing oligomer is preferably 0.01 to 10 parts by mass, more preferably 0.02 to 7.5 parts by mass, even more preferably 0.03 to 5.5 parts by mass, most preferably 0.03 to 5.5 parts by mass, based on 100 parts by mass of the base polymer. It is 0.04-4.8 mass parts. When it is within the above range, suppression of peeling electrification can be achieved after bonding the surface protection sheet of the present invention to an optical member or the like, which is preferable. Further, in order to satisfy stain resistance, it is preferably 0.01 to 5.5 parts by weight based on 100 parts by weight of the base polymer.

It is preferable that the adhesive composition of this invention contains a crosslinking agent. Moreover, in this invention, it can set it as an adhesive layer by mix|blending a crosslinking agent with the said adhesive composition. For example, when the pressure-sensitive adhesive contains the (meth)acrylic polymer, the (meth)acrylic polymer is crosslinked by appropriately adjusting the structural unit, composition ratio, selection and addition ratio of the crosslinking agent, etc., resulting in better heat resistance. A surface protection sheet (adhesive layer) can be obtained.

As the crosslinking agent used in the present invention, isocyanate compounds, epoxy compounds, melamine-based resins, aziridine derivatives, and metal chelate compounds can be used. In particular, use of isocyanate compounds is a preferred embodiment. Moreover, these compounds may be used independently and may mix and use 2 or more types.

Examples of the isocyanate compound include aliphatic polyisocyanates such as trimethylene diisocyanate, butylene diisocyanate, hexamethylene diisocyanate (HDI), dimer acid diisocyanate, cyclopentylene diisocyanate, cyclohexylene diisocyanate, and isocyanate. Alicyclic isocyanates such as phorone diisocyanate (IPDI), aromatic isocyanates such as 2,4-tolylene diisocyanate, 4,4'-diphenylmethane diisocyanate, and xylylene diisocyanate (XDI); and modified polyisocinates modified by a fanate bond, a biuret bond, an isocyanurate bond, a uretdione bond, a urea bond, a carbodiimide bond, a uretonimine bond, an oxadiazinetrione bond, and the like. For example, as a commercial item, the trade name Takenate 300S, Takenate 500, Takenate D165N, Takenate D178N (above, manufactured by Mitsui Chemicals), Smidur T80, Smidur L, Desmodur N3400 (above, Sumika Bayer Urethane Co., Ltd.) manufacture), milionate MR, milionate MT, colonate L, colonate HL, and colonate HX (above, manufactured by Tosoh Corporation), etc. are mentioned. These isocyanate compounds may be used individually, or may be used in mixture of two or more types, and it is also possible to use a bifunctional isocyanate compound and a trifunctional or higher functional isocyanate compound in combination. By using a crosslinking agent in combination, it becomes possible to achieve both adhesiveness and repelling resistance (adhesion to a curved surface), and a surface protection sheet having more excellent adhesion reliability can be obtained.

Examples of the epoxy compound include N,N,N',N'-tetraglycidyl-m-xylenediamine (trade name TETRAD-X, manufactured by Mitsubishi Gas Chemical Co., Ltd.) and 1,3-bis(N, N-diglycidyl aminomethyl) cyclohexane (trade name TETRAD-C, manufactured by Mitsubishi Gas Chemical Co., Ltd.); and the like.

Examples of the melamine-based resin include hexamethylolmelamine. As an aziridine derivative, commercially available product names HDU, TAZM, TAZO (above, Sogo Chemical Co., Ltd.), etc. are mentioned, for example.

As said metal chelate compound, aluminum, iron, tin, titanium, nickel etc. are mentioned as a metal component, Acetylene, methyl acetoacetate, ethyl lactate, etc. are mentioned as a chelate component.

The content of the crosslinking agent used in the present invention is, for example, as a base polymer, preferably 0.01 to 10 parts by mass, and 0.1 to 8 parts by mass, based on 100 parts by mass of the (meth)acrylic polymer. It is more preferable that it contains 0.5-5 parts by mass is still more preferable, and it is most preferable that it contains 1-4 parts by mass. When the content is less than 0.01 part by mass, crosslinking by the crosslinking agent becomes insufficient, the cohesive force of the resulting pressure-sensitive adhesive layer decreases, sufficient heat resistance may not be obtained, and it tends to cause glue remaining. On the other hand, when the content exceeds 10 parts by mass, the cohesive force of the polymer is high, the fluidity is lowered, and the wettability to the adherend (for example, polarizing film) becomes insufficient, and the adhesion between the adherend and the pressure-sensitive adhesive layer (pressure-sensitive adhesive composition layer) It tends to be the cause of the swelling that occurs between them. Further, when the amount of the crosslinking agent is large, the peeling charging characteristics tend to decrease.

The pressure-sensitive adhesive composition may further contain a crosslinking catalyst in order to more effectively advance any of the crosslinking reactions described above. As such a crosslinking catalyst, for example, tin-based catalysts such as dibutyltin dilaurate and dioctyltin dilaurate, tris(acetylacetonato)iron, tris(hexane-2,4-dionato)iron, tris(heptane) -2,4-dionato) iron, tris (heptane-3,5-dionato) iron, tris (5-methylhexane-2,4-dionato) iron, tris (octane-2,4-dionato) Iron, tris(6-methylheptane-2,4-dionato)iron, tris(2,6-dimethylheptane-3,5-dionato)iron, tris(nonane-2,4-dionato)iron, tris (nonane-4,6-dionato) iron, tris (2,2,6,6-tetramethylheptane-3,5-dionato) iron, tris (tridecane-6,8-dionato) iron, tris (1-phenylbutane-1,3-dionato)iron, tris(hexafluoroacetylacetonato)iron, tris(ethylacetoacetate)iron, tris(acetoacetate-n-propyl)iron, tris(isoacetoacetate) Propyl) iron, tris(acetoacetate-n-butyl) iron, tris(acetoacetate-sec-butyl) iron, tris(acetoacetate-tert-butyl) iron, tris(propionylmethylacetate) iron, tris(propionyl) Ethyl acetate) iron, tris(propionylacetate-n-propyl)iron, tris(propionylisopropylacetate)iron, tris(propionylacetate-n-butyl)iron, tris(propionylacetate-sec-butyl)iron , tris(propionyl acetate-tert-butyl) iron, tris(benzyl acetoacetate) iron, tris(dimethyl malonate) iron, tris(diethyl malonate) iron, trimethoxy iron, triethoxy iron, triisopropanol Iron-based catalysts such as iron oxide and ferric chloride can be used. One type of these crosslinking catalysts may be sufficient, and they may use 2 or more types together.

The content of the crosslinking catalyst is not particularly limited, but is preferably about 0.0001 to 1 part by mass, more preferably 0.001 to 0.5 part by mass, based on 100 parts by mass of the (meth)acrylic polymer as a base polymer, for example. When it exists in the said range, when forming an adhesive layer, the speed of crosslinking reaction is fast and the pot life of an adhesive composition also becomes long, and it becomes a preferable aspect.

In addition, the pressure-sensitive adhesive composition of the present invention may contain other known additives, for example, powders such as colorants and pigments, surfactants, plasticizers, tackifiers, low molecular weight polymers, surface lubricants, leveling agents, Antioxidants, corrosion inhibitors, light stabilizers, ultraviolet absorbers, polymerization inhibitors, silane coupling agents, crosslinking retardants, inorganic or organic fillers, metal powders, particulates, thin materials, etc. are appropriately used depending on the application. can be added.

The surface protective sheet of the present invention preferably has a pressure-sensitive adhesive layer formed from the pressure-sensitive adhesive composition (formed by crosslinking the pressure-sensitive adhesive composition) on one side of the support film. Crosslinking of the pressure-sensitive adhesive composition is generally performed after application of the pressure-sensitive adhesive composition, but it is also possible to transfer the pressure-sensitive adhesive layer composed of the pressure-sensitive adhesive composition after crosslinking to a support film or the like. In addition, the method of forming the pressure-sensitive adhesive layer on the support film is not particularly limited, but, for example, it is produced by applying the pressure-sensitive adhesive composition to the support film, drying and removing the polymerization solvent, etc. to form the pressure-sensitive adhesive layer on the support film. . Thereafter, curing may be performed for the purpose of adjusting migration of components in the pressure-sensitive adhesive layer or adjusting crosslinking reaction. In addition, when applying the pressure-sensitive adhesive composition onto the support film to prepare the surface protective sheet, one or more solvents other than the polymerization solvent may be newly added to the pressure-sensitive adhesive composition so that the pressure-sensitive adhesive composition can be applied uniformly on the support film.

<support film>

As the support film, the resin material constituting the support film can be used without particular limitation, but, for example, one having excellent properties such as transparency, mechanical strength, thermal stability, moisture barrier property, isotropy, flexibility, and dimensional stability. It is preferable to use In particular, when the support film has flexibility, the pressure-sensitive adhesive composition can be applied by a roll coater or the like and can be wound into a roll, which is useful.

Examples of the support film (substrate) include polyester polymers such as polyethylene terephthalate (PET), polyethylene naphthalate (PEN), and polybutylene terephthalate; cellulose polymers such as diacetyl cellulose and triacetyl cellulose. ; polycarbonate-based polymer; acrylic polymer such as polymethyl methacrylate; etc. as the main resin component (the main component in the resin component, typically 50% by mass or more), a plastic film composed of a resin material, the support It can be used suitably as a film. Other examples of the resin material include styrenic polymers such as polystyrene and acrylonitrile-styrene copolymers; olefins such as polyethylene, polypropylene, polyolefins having a cyclic or norbornene structure, and ethylene-propylene copolymers. Polymers; Vinyl chloride-based polymers; amide-based polymers such as nylon 6, nylon 6,6, and aromatic polyamide; and the like as resin materials. As another example of the resin material, an imide-based polymer, a sulfone-based polymer, a polyether sulfone-based polymer, a polyether ether ketone-based polymer, a polyphenylene sulfide-based polymer, a vinyl alcohol-based polymer, a vinylidene chloride-based polymer, and a vinyl butyric acid polymer. A ral type polymer, an arylate type polymer, a polyoxymethylene type polymer, an epoxy type polymer, etc. are mentioned. It may be a support film composed of a blend of two or more of the polymers described above.

As the support film, a plastic film made of a transparent thermoplastic resin material can be preferably employed. Among the above plastic films, it is a more preferable aspect to use a polyester film. Here, the polyester film refers to a polymer material (polyester resin) having a main skeleton based on ester bonds such as polyethylene terephthalate (PET), polyethylene naphthalate (PEN), and polybutylene terephthalate as the main resin component. say to do Such a polyester film has desirable properties as a support film for a pressure-sensitive adhesive sheet, such as excellent optical properties and dimensional stability, but also has a property of being easily charged as it is.

Various additives such as antioxidants, ultraviolet absorbers, plasticizers, and colorants (pigments, dyes, etc.) may be incorporated into the resin material constituting the support film, if necessary. On the surface of the polyester film on the side where the antistatic layer is formed, a known or conventional surface treatment such as corona discharge treatment, plasma treatment, ultraviolet irradiation treatment, acid treatment, alkali treatment, coating of a primer is applied, for example. may have been carried out. Such a surface treatment may be, for example, treatment for enhancing the adhesion between the support film and the antistatic layer. A surface treatment in which a polar group such as a hydroxyl group is introduced into the surface of the support film can be preferably employed. Moreover, surface treatment similar to the above may be given to the surface of the support film on the side where the adhesive layer is formed. Such surface treatment may be a treatment for enhancing the adhesion between the film and the pressure-sensitive adhesive layer (anchoring property of the pressure-sensitive adhesive layer).

In addition, the surface protective sheet of the present invention can have an antistatic function in the support film, but in the case of having an antistatic function, it is also possible to use a plastic film that has been subjected to antistatic treatment as the support film. . The use of the support film is preferable because the surface protection sheet itself is prevented from being charged when peeled off. In addition, the support film is a plastic film, and antistatic treatment is applied to the plastic film to reduce the surface protection sheet itself from being charged and to obtain an excellent antistatic ability with respect to adherends. In addition, the method for imparting the antistatic function is not particularly limited, and a conventionally known method can be used. For example, an antistatic resin composed of an antistatic agent and a resin component, a conductive polymer, or a conductive material containing a conductive material. A method of applying a conductive resin, a method of depositing or plating a conductive material, and a method of kneading an antistatic agent or the like may be mentioned.

The thickness of the support film is usually about 5 to 200 μm, and preferably about 10 to 100 μm. When the thickness of the support film is within the above range, it is preferable because bonding workability to the adherend and peeling workability from the adherend are excellent.

In addition, as a method for forming the pressure-sensitive adhesive layer in the production of the surface protective sheet of the present invention, a known method used in the production of pressure-sensitive adhesive sheets is used. Specifically, for example, roll coating, gravure coating, reverse coating, roll brush coating, spray coating, air knife coating method, extrusion coating method by a die coater, etc. are exemplified.

The surface protective sheet of the present invention is usually manufactured so that the thickness of the pressure-sensitive adhesive layer is preferably about 3 to 100 μm, more preferably about 5 to 50 μm. When the thickness of the pressure-sensitive adhesive layer is within the above range, it is easy to obtain a balance between appropriate re-peelability and adhesiveness (adhesiveness), so it is preferable.

<Separator>

In the surface protection sheet of the present invention, if necessary, a separator can be bonded to the surface of the pressure-sensitive adhesive layer for the purpose of protecting the adhesive surface.

Although there are paper and plastic films as the material constituting the separator, a plastic film is preferably used because of its excellent surface smoothness. The film is not particularly limited as long as it can protect the pressure-sensitive adhesive layer, and examples include a polyethylene film, a polypropylene film, a polybutene film, a polybutadiene film, a polymethylpentene film, a polyvinyl chloride film, and a chloride film. A vinyl copolymer film, a polyethylene terephthalate film, a polybutylene terephthalate film, a polyurethane film, an ethylene-vinyl acetate copolymer film, etc. are mentioned.

The thickness of the separator is usually about 5 to 200 μm, preferably about 10 to 100 μm. When it is within the above range, the bonding workability to the pressure-sensitive adhesive layer and the peeling workability from the pressure-sensitive adhesive layer are excellent, so it is preferable. If necessary, the separator may be subjected to release and antifouling treatment using a silicone-based, fluorine-based, long-chain alkyl-based or fatty acid amide-based release agent, silica powder, or the like, or antistatic treatment such as coating, kneading, or vapor deposition. .

<Antistatic layer>

The surface protective sheet of the present invention has an antistatic layer on a surface opposite to the pressure-sensitive adhesive layer formed on the support film, and the antistatic layer contains polyanilines and/or polythiophenes as a conductive polymer component. It is preferably formed from the containing antistatic agent composition. When the surface protection sheet has an antistatic layer, it is possible to reduce the charge of the surface protection sheet itself and to have excellent antistatic ability with respect to adherends, which is a preferred embodiment.

<Conductive Polymer>

It is preferable that the antistatic agent composition used for formation of the said antistatic layer contains polyanilines and/or polythiophenes as a conductive polymer component. By using the conductive polymer, antistatic properties in a low temperature environment can be satisfied.

Examples of the polyanilines include polyaniline, poly(2-methylaniline), poly(3-isobutylaniline), poly(2-anilinesulfonic acid), and poly(3-anilinesulfonic acid).

The weight average molecular weight (Mw) of the polyanilines in terms of polystyrene is preferably 5 × 10 ⁵ or less, and more preferably 3 × 10 ⁵ or less. Moreover, the weight average molecular weight of these conductive polymers is usually preferably 1 × 10 ³ or higher, and more preferably 5 × 10 ³ or higher.

Among the polyanilines, commercially available products of the polyaniline sulfonic acid include "aqua-PASS", a trade name manufactured by Mitsubishi Rayon Co., Ltd., and the like.

Examples of the polythiophenes include polythiophene, poly(3-methylthiophene), poly(3-ethylthiophene), poly(3-propylthiophene), and poly(3-butylthiophene). , poly(3-hexylthiophene), poly(3-heptylthiophene), poly(3-octylthiophene), poly(3-decylthiophene), poly(3-dodecylthiophene), poly(3- octadecylthiophene), poly(3-bromothiophene), poly(3-chlorothiophene), poly(3-iodothiophene), poly(3-cyanothiophene), poly(3-phenylthiophene) , poly(3,4-dimethylthiophene), poly(3,4-dibutylthiophene), poly(3-hydroxythiophene), poly(3-methoxythiophene), poly(3-ethoxythiophene) ), poly(3-butoxythiophene), poly(3-hexyloxythiophene), poly(3-heptyloxythiophene), poly(3-octyloxythiophene), poly(3-decyloxythiophene) , poly(3-dodecyloxythiophene), poly(3-octadecyloxythiophene), poly(3,4-dihydroxythiophene), poly(3,4-dimethoxythiophene), poly(3 ,4-diethoxythiophene), poly(3,4-dipropoxythiophene), poly(3,4-dibutoxythiophene), poly(3,4-dihexyloxythiophene), poly(3, 4-diheptyloxythiophene), poly(3,4-dioctyloxythiophene), poly(3,4-didecyloxythiophene), poly(3,4-didodecyloxythiophene), poly(3,4 -Ethylenedioxythiophene), poly(3,4-propylenedioxythiophene), poly(3,4-butenedioxythiophene), poly(3-methyl-4-methoxythiophene), poly(3-methyl- 4-ethoxythiophene), poly(3-carboxythiophene, poly(3-methyl-4-carboxythiophene), poly(3-methyl-4-carboxyethylthiophene), poly(3-methyl-4- carboxybutylthiophene), etc. Among them, poly(3,4-ethylenedioxythiophene) is preferable from the viewpoint of conductivity.

As the polythiophenes, the weight average molecular weight (Mw) in terms of polystyrene is preferably 4 × 10 ⁵ or less, and more preferably 3 × 10 ³ or less. Moreover, Mw of polythiophenes is usually preferably 1×10 ³ or more, more preferably 5×10 ³ or more.

As the polythiophenes, it is also possible to use polythiophenes doped with polyanions.

The polyanions are polymers of constituent units having an anion group, and act as dopants for polythiophenes. Examples of the polyanions include polystyrene sulfonic acid, polyvinyl sulfonic acid, polyallyl sulfonic acid, polyacryl sulfonic acid, polymethacryl sulfonic acid, poly(2-acrylamide-2-methylpropane sulfonic acid), polyisoprene sulfonic acid, and polysulfonic acid. Ethyl methacrylate, poly(4-sulfobutyl methacrylate), polymethalyloxybenzenesulfonic acid, polyvinylcarboxylic acid, polystyrenecarboxylic acid, polyallylcarboxylic acid, polyacrylic carboxylic acid, polymethacrylic acid boxylic acid, poly(2-acrylamide-2-methylpropanecarboxylic acid), polyisoprenecarboxylic acid, polyacrylic acid, and polysulfonated phenylacetylene. These homopolymers may be sufficient, and 2 or more types of copolymers may be sufficient. Among them, polystyrene sulfonic acid is preferable.

The weight average molecular weight (Mw) of the said polyanions is preferably 1,000 to 1,000,000, more preferably 2,000 to 500,000. If it is within the above range, it is preferable because doping and dispersibility to polythiophenes are excellent.

Commercially available products of polythiophenes doped with the above polyanions include, for example, poly(3,4-ethylenedioxythiophene)/polystyrenesulfonic acid (PEDOT/PSS) trade name "Bytron P" manufactured by BAYER. , brand name "Cefulida" manufactured by Shin-Etsu Polymer Co., Ltd., trade name "Verazole" manufactured by Soken Chemical Co., Ltd., and the like are exemplified.

<binder>

The antistatic agent composition used for formation of the antistatic layer preferably contains a binder component in order to impart mechanical strength and thermal stability. Examples of the binder component include acrylic resins, silicone resins, fluororesins, styrene resins, polyester resins, alkyd resins, urethane resins, amide resins, polyolefin resins, and modified or copolymerized resins thereof. Moreover, you may use the said resin individually or in combination of 2 or more types. Among the above resins, a polyester resin is preferably used because it achieves both mechanical strength and charging characteristics.

The polyester resin is preferably a resin material containing polyester as a main component (typically more than 50% by mass, preferably 75% by mass or more, for example, 90% by mass or more). The polyesters are typically polyvalent carboxylic acids (typically dicarboxylic acids) having two or more carboxyl groups in one molecule and derivatives thereof (anhydrides, esterified products, halides, etc. of the polyvalent carboxylic acids). One or two or more compounds selected from (polyhydric carboxylic acid component) and one or two or more compounds selected from polyhydric alcohols (typically diols) having two or more hydroxyl groups in one molecule (Polyhydric alcohol component) It is preferable to have a condensed structure.

Examples of compounds that can be employed as the polyhydric carboxylic acid component include oxalic acid, malonic acid, difluoromalonic acid, alkylmalonic acid, succinic acid, tetrafluorosuccinic acid, alkylsuccinic acid, (±)-malic acid, and meso-tartaric acid. , itaconic acid, maleic acid, methyl maleic acid, fumaric acid, methyl fumaric acid, acetylenedicarboxylic acid, glutaric acid, hexafluoroglutaric acid, methylglutaric acid, glutaconic acid, adipic acid, dithioadipic acid , methyladipic acid, dimethyladipic acid, tetramethyladipic acid, methyleneadipic acid, muconic acid, galactaric acid, pimelic acid, suberic acid, perfluorosuberic acid, 3,3,6,6 -Aliphatic dicarboxylic acids such as tetramethylsuberic acid, azelaic acid, sebacic acid, perfluorosebacic acid, brassylic acid, dodecyldicarboxylic acid, tridecyldicarboxylic acid, and tetradecyldicarboxylic acid Acids; Cycloalkyldicarboxylic acid (eg, 1,4-cyclohexanedicarboxylic acid, 1,2-cyclohexanedicarboxylic acid), 1,4-(2-norbornene)dicarboxylic acid acid, 5-norbornene-2,3-dicarboxylic acid (hymic acid), adamantane dicarboxylic acid, alicyclic dicarboxylic acids such as spiroheptane dicarboxylic acid; phthalic acid, isophthalic acid, dithiocyanate Oisophthalic acid, methylisophthalic acid, dimethylisophthalic acid, chloroisophthalic acid, dichloroisophthalic acid, terephthalic acid, methylterephthalic acid, dimethylterephthalic acid, chloroterephthalic acid, bromoterephthalic acid, naphthalenedicarboxylic acid, oxofluorenedicarboxylic acid, anthracendica carboxylic acid, biphenyldicarboxylic acid, biphenylenedicarboxylic acid, dimethylbiphenylenedicarboxylic acid, 4,4''-p-terephenylenedicarboxylic acid, 4,4''- p-qualerphenyldicarboxylic acid, bibenzyldicarboxylic acid, azobenzenedicarboxylic acid, homophthalic acid, phenylene diacetic acid, phenylenedipropionic acid, naphthalenedicarboxylic acid, naphthalenedipropionic acid, biphenyl diacetic acid , biphenyldipropionic acid, 3,3'-[4,4'-(methylenedi-p-biphenylene)dipropionic acid, 4,4'-bibenzyldiacetic acid, 3,3'(4,4'- Aromatic dicarboxylic acids such as bibenzyl)dipropionic acid and oxydi-p-phenylene diacetic acid; acid anhydrides of any of the above polyvalent carboxylic acids; esters of any of the above polyvalent carboxylic acids (for example listen alkyl esters, monoesters, diesters, etc.); acid halides corresponding to any of the above polyvalent carboxylic acids (eg dicarboxylic acid chloride); and the like.

Preferable examples of the compound employable as the polyhydric carboxylic acid component include aromatic dicarboxylic acids such as terephthalic acid, isophthalic acid, and naphthalenedicarboxylic acid, and acid anhydrides thereof; adipic acid, sebacic acid, azelaic acid, Aliphatic dicarboxylic acids and their acid anhydrides, such as succinic acid, fumaric acid, maleic acid, hymic acid and 1,4-cyclohexanedicarboxylic acid; ester with monoalcohol of 1-3) etc. are mentioned.

On the other hand, examples of compounds that can be employed as the polyhydric alcohol component include ethylene glycol, propylene glycol, 1,2-propanediol, 1,3-propanediol, 1,3-butanediol, 1,4-butanediol, and neopentyl. Glycol, 1,5-pentanediol, 1,6-hexanediol, 3-methylpentanediol, diethylene glycol, 1,4-cyclohexanedimethanol, 3-methyl-1,5-pentanediol, 2-methyl- Diols such as 1,3-propanediol, 2,2-diethyl-1,3-propanediol, 2-butyl-2-ethyl-1,3-propanediol, xylylene glycol, hydrogenated bisphenol A, and bisphenol A Ryu can be heard. As another example, alkylene oxide adducts (for example, ethylene oxide adducts, propylene oxide adducts, etc.) of these compounds are mentioned.

The molecular weight of the polyester resin is, for example, about 5 × 10 ³ to 1.5 × 10 ⁵ (preferably 1 × 10 ⁴ to about 6 × 10 ⁴ ). In addition, the glass transition temperature (Tg) of the polyester resin may be, for example, 0 to 120°C (preferably 10 to 80°C).

As the polyester resin, commercially available products such as "Vironal MD-1480" manufactured by Toyobo Co., Ltd. can be used.

The antistatic agent composition used in the formation of the antistatic layer may contain a binder other than a polyester resin as a binder, to the extent that the performance (eg, antistatic performance, etc.) of the surface protection sheet disclosed herein is not significantly impaired. A resin (for example, one or two or more resins selected from acrylic resins, acrylethane resins, acrylic styrene resins, acrylic silicone resins, silicone resins, polysilazane resins, polyurethane resins, fluororesins, polyolefin resins, etc.) may contain more. As a preferable aspect of the technique disclosed herein, the binder included in the antistatic agent composition is substantially composed of only a polyester resin. For example, an antistatic layer (antistatic agent composition) in which the proportion of the polyester resin in the binder is 98 to 100% by mass is preferable. The proportion of the binder in the entire antistatic layer can be, for example, 50 to 95% by mass, and usually preferably 60 to 90% by mass.

The content of the conductive polymer is preferably 10 to 200 parts by mass, more preferably 25 to 150 parts by mass, and still more preferably based on 100 parts by mass of the binder contained in the antistatic agent composition used for forming the antistatic layer. It is 40-120 mass parts. If the content of the conductive polymer is too small, the antistatic effect may be reduced, and if the content of the conductive polymer is too large, the adhesion of the antistatic layer to the supporting film may deteriorate or the transparency may decrease, which is not preferable. .

Although the antistatic agent composition used for formation of the antistatic layer disclosed herein may contain polyanilines and/or polythiophenes as a conductive polymer component, for example, one or two other types may be used. The above antistatic components (organic conductive substances other than conductive polymers, inorganic conductive substances, antistatic agents, etc.) may also be included.

Examples of the organic conductive material include quaternary ammonium salts, pyridinium salts, cationic antistatic agents having cationic functional groups such as primary amino groups, secondary amino groups, and tertiary amino groups; sulfonic acid salts, sulfuric acid ester salts, phosphonic acid salts, and phosphoric acid; Anionic antistatic agents having anionic functional groups such as ester salts; zwitterionic antistatic agents such as alkyl betaines and derivatives thereof, imidazoline and derivatives thereof, alanine and derivatives thereof; amino alcohols and derivatives thereof; glycerin and derivatives thereof; Derivatives, nonionic antistatic agents such as polyethylene glycol and derivatives thereof; ions obtained by polymerization or copolymerization of monomers having an ionic conductive group (eg, quaternary ammonium salt group) of the above cationic, anionic, and amphoteric ions Conductive polymers; Conductive polymers such as polythiophene, polyaniline, polypyrrole, polyethyleneimine, and allylamine polymers; Such an antistatic agent may be used individually by 1 type, and may be used in combination of 2 or more type.

Examples of the inorganic conductive material include tin oxide, antimony oxide, indium oxide, cadmium oxide, titanium oxide, zinc oxide, indium, tin, antimony, gold, silver, copper, aluminum, nickel, chromium, titanium, iron, cobalt, and iodide. Copper, ITO (indium oxide/tin oxide), ATO (antimony oxide/tin oxide), etc. are mentioned. Such an inorganic conductive substance may be used individually by 1 type, and may be used in combination of 2 or more type.

As the antistatic agent, a cationic antistatic agent, an anionic antistatic agent, an amphoteric antistatic agent, a nonionic antistatic agent, a monomer having an ionic conductive group of the cationic type, anionic type, or zwitterionic type may be polymerized or Ion conductive polymer obtained by copolymerization, etc. are mentioned.

＜Lubricant (滑劑)＞

In the antistatic agent composition used for formation of the antistatic layer disclosed herein, it is preferable to use, as a lubricant, at least one selected from the group consisting of fatty acid amides, silicone lubricants, fluorine lubricants, and wax lubricants. As a lubricant, by using at least one selected from the group consisting of fatty acid amide, silicone-based lubricant, fluorine-based lubricant, and wax-based lubricant, additional peeling treatment on the surface of the antistatic layer (eg, silicone-based release agent, long-chain alkyl-based lubricant) Even in the mode in which a known release treatment agent such as a release agent is applied and dried) is not performed, since an antistatic layer having both sufficient slipperiness and printing adhesion can be obtained, it can be a preferable mode. In this way, the aspect in which the surface of the antistatic layer is not subjected to additional peeling treatment is that whitening caused by the peeling agent (for example, whitening caused by being stored under heating and humid conditions) can be prevented in advance. desirable. Moreover, the point of solvent resistance is also advantageous.

Moreover, it is preferable to use a fatty acid amide especially as a lubricant. By using a fatty acid amide as a lubricant, both slipperiness and printing adhesion become easy on the surface of the antistatic layer, and an excellent antistatic layer is obtained, so it can be a preferred embodiment.

Specific examples of the fatty acid amide include lauric acid amide, palmitic acid amide, stearic acid amide, behenic acid amide, hydroxystearic acid amide, oleic acid amide, erucic acid amide, N-oleyl palmitic acid amide, N -Stearyl stearic acid amide, N-stearyl oleic acid amide, N-oleyl stearic acid amide, N-stearyl erucic acid amide, methylol stearic acid amide, methylenebis stearic acid amide, ethylene biscapric acid amide, ethylene Bislauric acid amide, ethylenebis stearic acid amide, ethylene bishydroxystearic acid amide, ethylene bisbehenic acid amide, hexamethylene bis stearic acid amide, hexamethylene bisbehenic acid amide, hexamethylene hydroxystearic acid amide, N, N'-distearyladipic acid amide, N,N'-distearylsebacic acid amide, ethylenebisoleic acid amide, ethylenebiserucic acid amide, hexamethylenebisoleic acid amide, N,N'-dioleyladipic acid amide, N,N'-dioleyl sebacic acid amide, m-xylylenebisstearic acid amide, m-xylylenebishydroxystearic acid amide, N,N'-stearyl isophthalic acid amide, and the like. These lubricants may be used individually by 1 type, and may be used in combination of 2 or more type.

The ratio of the lubricant to the entire antistatic layer can be 1 to 50% by mass, and is usually suitably 5 to 40% by mass. When the content ratio of the lubricant is too small, there is a tendency that the slipperiness tends to decrease. When the content ratio of the lubricant is too large, there may be cases where the printing adhesiveness is lowered.

The technology disclosed herein can be implemented in an aspect in which the antistatic agent composition used for forming the antistatic layer contains other lubricants in addition to the fatty acid amide, to the extent that the application effect is not significantly impaired. Examples of such other lubricants include various waxes such as petroleum wax (such as paraffin wax), mineral wax (such as montan wax), higher fatty acids (such as cerotic acid), and neutral fats (such as palmitic acid triglyceride). Alternatively, in addition to the above wax, a general silicone-based lubricant, a fluorine-based lubricant, or the like may be additionally contained. The technology disclosed herein can be preferably carried out in an aspect that does not substantially contain such silicone-based lubricants, fluorine-based lubricants, and the like. However, to the extent that the application effect of the technique disclosed herein is not significantly impaired, it contains a silicone-based compound used for a purpose other than the lubricant (for example, as an antifoaming agent included in a coating material for forming an antistatic layer described later). does not exclude

<Crosslinking agent>

The antistatic agent composition used in the formation of the antistatic layer is composed of a silane coupling agent, an epoxy-based crosslinking agent, a melamine-based crosslinking agent, an isocyanate-based crosslinking agent, an oxazoline-based crosslinking agent, a carbodiimide-based crosslinking agent, and an organic metal-based crosslinking agent as a crosslinking agent It is a preferable aspect to use at least 1 sort(s) selected from group. Among them, by using the melamine-based crosslinking agent or the isocyanate-based crosslinking agent, in particular, polyanilines and polythiophenes as conductive polymer components used when forming the antistatic layer can be fixed in a binder, and the water resistance and solvent resistance are excellent. In addition, effects such as improvement of printing adhesiveness can be realized. In particular, by using a melamine-based solvent, water resistance and solvent resistance are improved, by using an isocyanate-based crosslinking agent, water resistance and printing adhesion are improved, and by using these together, water resistance, solvent resistance, and printing adhesion are improved and useful.

As the isocyanate-based crosslinking agent, it is preferable to use a blocked isocyanate-based crosslinking agent that is stable even in an aqueous solution. Specific examples of the blocked isocyanate-based crosslinking agent include an isocyanate-based crosslinking agent (eg, an isocyanate compound (isocyanate-based crosslinking agent) used in the above-mentioned pressure-sensitive adhesive layer) that can be used when preparing a general pressure-sensitive adhesive layer or antistatic layer, and alcohols. , phenols, thiophenols, amines, imides, oximes, lactams, active methylene compounds, mercaptans, imines, ureas, diaryl compounds, and those blocked with sodium bisulfite or the like can be used. .

As the melamine-based crosslinking agent, melamine, alkylated melamine, methylol melamine, alkoxylated methyl melamine and the like can be used.

Antistatic layer in the technique disclosed herein, if necessary, antioxidant, colorant (pigment, dye, etc.), fluidity modifier (thixotropic agent, thickener, etc.), film forming auxiliary agent, surfactant (foaming agent, etc.) ), preservatives, and additives such as ultraviolet absorbers.

<Formation of antistatic layer>

In the antistatic layer, a liquid composition (a coating material for forming an antistatic layer, an antistatic agent composition, an antistatic agent solution) in which the conductive polymer component and the like and additives used as necessary are dissolved in an appropriate solvent (such as water) is applied to a support film. It can be suitably formed by a method including imparting. For example, a method of applying the coating material to one side of a support film, drying it, and performing a curing treatment (heat treatment, ultraviolet treatment, etc.) if necessary can be preferably employed. The NV (non-volatile matter) of the coating material can be, for example, 5% by mass or less (typically 0.05 to 5% by mass), and usually 1% by mass or less (typically 0.10 to 1% by mass). it is appropriate to When forming an antistatic layer with a small thickness, it is preferable to make NV of the said coating material into 0.05-0.50 mass % (eg 0.10-0.40 mass %), for example. By using such a low NV coating material, a more uniform antistatic layer can be formed.

The solvent constituting the coating material is preferably one capable of stably dissolving the components for forming the antistatic layer. This solvent may be an organic solvent, water, or a mixed solvent thereof. Examples of the organic solvent include esters such as ethyl acetate; ketones such as methyl ethyl ketone, acetone, and cyclohexanone; cyclic ethers such as tetrahydrofuran (THF) and dioxane; n-hexane; Aliphatic or alicyclic hydrocarbons such as cyclohexane; Aromatic hydrocarbons such as toluene and xylene; Aliphatic or alicyclic alcohols such as methanol, ethanol, n-propanol, isopropanol and cyclohexanol; Alkylene glycol monoalkyl ethers ( For example, glycol ethers, such as ethylene glycol monomethyl ether, ethylene glycol monoethyl ether), and dialkylene glycol monoalkyl ether; etc. 1 type(s) or 2 or more types selected from these can be used. In a preferred aspect, the solvent of the coating material is water or a mixed solvent containing water as a main component (for example, a mixed solvent of water and ethane).

<Properties of the antistatic layer>

The antistatic layer has a thickness of typically 3 to 500 nm, preferably 3 to 100 nm, and more preferably 3 to 60 nm. If the thickness of the antistatic layer is too small, it becomes difficult to uniformly form the antistatic layer (for example, the thickness of the antistatic layer varies greatly depending on the location), and for this reason, the appearance of the surface protection sheet is affected. There may be cases where non-uniformity becomes easy to occur. On the other hand, if it is too thick, the properties of the support film (optical properties, dimensional stability, etc.) may be affected.

In a preferable aspect of the surface protection sheet disclosed herein, the surface resistance value (Ω/□) measured on the surface of the antistatic layer is preferably less than 1.0 × 10 ¹¹ , more preferably 5.0 × 10 ¹⁰ less than, more preferably less than 2.0 × 10 ¹⁰ . A surface protection sheet exhibiting a surface resistance value within the above range can be suitably used as a surface protection sheet used in processing or transporting an article that dislikes static electricity, such as, for example, a liquid crystal cell or a semiconductor device. In addition, the said surface resistance value is computable from the surface resistance value measured in the atmosphere of 23 degreeC and 50 %RH using a commercially available insulation resistance measurement apparatus.

The surface protection sheet disclosed herein may be implemented in an aspect including further other layers in addition to the support film (substrate), the pressure-sensitive adhesive layer, and the antistatic layer. As arrangement of such "another layer", between a support film and an antistatic layer, between a support film and an adhesive layer, etc. are illustrated. For example, the layer disposed between the support film and the pressure-sensitive adhesive layer may be an undercoating layer (anchor layer), an antistatic layer, or the like that enhances anchoring properties with the pressure-sensitive adhesive layer. An antistatic layer may be separately disposed between the support film and the pressure-sensitive adhesive layer, and an anchor layer may be disposed between the antistatic layer and the pressure-sensitive adhesive layer.

<Optical member>

The optical member of the present invention is preferably protected by the surface protection sheet. The surface protection sheet can be used for surface protection such as during processing, conveyance, and shipment, and is useful for protecting the surface of the optical member (such as a polarizing film). In particular, since it is possible to peel easily at a stage where a surface protection sheet becomes unnecessary with respect to a thin optical member (such as a polarizing film) or a display panel, it is very useful.

The optical member of this invention is a polarizing film containing a polarizer, and it is preferable that the thickness of the said polarizer is 8 micrometers or less. A thin optical member having a polarizer thickness of 8 μm or less tends to deteriorate particularly the peeling charge suppression effect, and the problem of peeling charge is improved by applying the surface protection sheet, and in an optical member (polarizing film), It becomes a useful and desirable aspect.

<Polarizing film>

As said polarizing film, the thing of the structure which laminated|stacked a transparent protective film on at least one surface of a polarizer and a polarizer, and laminated|stacked the 1st adhesive layer on at least one surface of the said polarizing film can be used.

<Polarizer>

As for the polarizer, a polyvinyl alcohol-based resin is used. As the polarizer, for example, a polyvinyl alcohol-based film, a partially formalized polyvinyl alcohol-based film, or a hydrophilic polymer film such as an ethylene-vinyl acetate copolymer-based partially saponified film adsorbs a dichroic substance such as iodine or a dichroic dye. polyene-based oriented films such as those obtained by making and uniaxially stretched, dehydrated products of polyvinyl alcohol, and dehydrochlorinated products of polyvinyl chloride; and the like. Among these, a polarizer composed of a polyvinyl alcohol-based film and a dichroic substance such as iodine is suitable.

A polarizer obtained by dyeing the polyvinyl alcohol-based film with iodine and stretching it uniaxially can be produced by, for example, dyeing polyvinyl alcohol by immersing it in an aqueous solution of iodine and stretching it to 3 to 7 times the original length. Boric acid, zinc sulfate, zinc chloride, etc. may be included as needed, and it may be immersed in aqueous solution, such as potassium iodide. Further, if necessary, the polyvinyl alcohol-based film may be immersed in water and washed before dyeing. By washing the polyvinyl alcohol-based film with water, stains and antiblocking agents on the surface of the polyvinyl alcohol-based film can be washed away, and unevenness such as dyeing unevenness is prevented by swelling the polyvinyl alcohol-based film. Stretching may be performed after dyeing with iodine, may be performed while dyeing, or may be further stretched and then dyed with iodine. It can also be stretched in an aqueous solution such as boric acid or potassium iodide or in a water bath.

The thickness of the polarizer is preferably 8 μm or less, more preferably 7 μm or less, still more preferably 6 μm or less from the viewpoint of thinning. On the other hand, the thickness of the polarizer is preferably 2 μm or more, and more preferably 3 μm or more. Since such a thin polarizer has little thickness nonuniformity, excellent visibility, and little dimensional change, it is excellent in durability against thermal shock. As a thin polarizer, typically, Japanese Patent No. 4751486 specification, Japanese Patent No. 4751481 specification, Japanese Patent No. 4815544 specification, Japanese Patent No. 5048120 specification, International Publication No. 2014/077599 Pamphlet, International Publication No. The thin polarizer described in 2014/077636 pamphlet etc. or the thin polarizer obtained from the manufacturing method described in these are mentioned.

The polarizer has optical properties represented by single transmittance T and polarization P, the following formula P> -(100.929T - 42.4 - 1) × 100 (provided T < 42.3), or P ≥ 99.9 (provided T ≥ 42.3) is preferably configured). A polarizer configured to satisfy the above conditions uniquely has performance required as a display for a liquid crystal television using a large display element. Specifically, the contrast ratio is 1000:1 or more and the maximum luminance is 500 cd/m 2 or more. For another use, it is bonded to the visual recognition side of an organic EL cell, for example.

Among the manufacturing methods including the step of stretching in a laminate state and the step of dyeing, the thin polarizer can be stretched at a high magnification and the polarization performance can be improved. It is preferably obtained by a manufacturing method including a step of stretching in a boric acid aqueous solution as described in the specification of Japanese Patent No. 4815544, and in particular in the aqueous boric acid solution described in the specification of Japanese Patent No. 4751481 and Japanese Patent No. 4815544. What is obtained by the manufacturing method including the process of air-stretching auxiliary before extending|stretching is preferable. These thin polarizers can be obtained by a manufacturing method including a process of stretching a polyvinyl alcohol-based resin (hereinafter also referred to as a PVA-based resin) layer and a resin base film for stretching in a laminate state, and a dyeing process. According to this manufacturing method, even if the PVA-based resin layer is thin, it is possible to extend it without problems such as breakage due to stretching by being supported by the resin base film for stretching.

<transparent protective film>

The material constituting the transparent protective film is not particularly limited, but it is preferable to have excellent transparency, mechanical strength, thermal stability, water barrier properties, isotropy, and the like. For example, polyester polymers such as polyethylene terephthalate and polyethylene naphthalate, cellulose polymers such as diacetyl cellulose and triacetyl cellulose, acrylic polymers such as polymethyl methacrylate, polystyrene and acrylonitrile/styrene copolymers Styrene type polymers, such as (AS resin), a polycarbonate type polymer, etc. are mentioned. In addition, polyethylene, polypropylene, polyolefins having a cyclo- or norbornene structure, polyolefin-based polymers such as ethylene-propylene copolymers, vinyl chloride-based polymers, amide-based polymers such as nylon and aromatic polyamides, imide-based polymers, alcohol Phone-based polymer, polyether sulfone-based polymer, polyether ether ketone-based polymer, polyphenylene sulfide-based polymer, vinyl alcohol-based polymer, vinylidene chloride-based polymer, vinyl butyral-based polymer, arylate-based polymer, polyoxymethylene-based polymer, Examples of polymers forming the transparent protective film include epoxy-based polymers, blends of the above polymers, and the like. These transparent protective films are usually bonded to a polarizer with an adhesive bond layer. Moreover, one or more types of arbitrary appropriate additives may be contained in the transparent protective film. As an additive, a ultraviolet absorber, an antioxidant, a lubricant, a plasticizer, a release agent, a coloring agent, a flame retardant, a nucleating agent, an antistatic agent, a pigment, a coloring agent, etc. are mentioned, for example.

The content of the thermoplastic resin in the transparent protective film is preferably 50 to 100% by mass, more preferably 50 to 99% by mass, still more preferably 60 to 98% by mass, and particularly preferably 70 to 97% by mass. to be. When the content of the thermoplastic resin in the transparent protective film is 50% by mass or less, there is a risk that the high transparency and the like originally possessed by the thermoplastic resin cannot be sufficiently expressed.

The thickness of the transparent protective film can be determined appropriately, but in general, it is preferably 5 to 50 μm, more preferably 5 to 45 μm, from the viewpoints of strength, workability such as handling and thin layer properties, etc. .

A functional layer such as a hard coat layer, an antireflection layer, an antisticking layer, a diffusion layer or an antiglare layer may be formed on the surface of the transparent protective film to which the polarizer is not adhered. In addition, the functional layer such as the hard coat layer, antireflection layer, antisticking layer, diffusion layer or antiglare layer can be formed on the transparent protective film itself or separately from the transparent protective film. may be

The transparent protective film and the polarizer are laminated through intervening layers such as an adhesive layer, an adhesive layer, and an undercoat layer (primer layer). At this time, it is preferable to laminate both layers without an air gap by means of an intervening layer.

The adhesive layer is formed of an adhesive. The type of adhesive is not particularly limited, and various types may be used. The adhesive layer is not particularly limited as long as it is optically transparent, and various types of adhesives such as water-based adhesives, solvent-based adhesives, hot-melt adhesives, and active energy ray-curable adhesives are used, but water-based adhesives or active energy ray-curable adhesives are suitable.

Examples of the water-based adhesive include isocyanate-based adhesives, polyvinyl alcohol-based adhesives, gelatin-based adhesives, vinyl-based latex-based adhesives, and water-based polyesters. Water-based adhesives are usually used as adhesives composed of aqueous solutions, and usually contain 0.5 to 60% by mass of solid content.

The active energy ray-curable adhesive is an adhesive that is cured by active energy rays such as electron beams and ultraviolet rays (radical curing type and cation curing type). For example, it can be used in an electron beam curing type or ultraviolet curing type. As the active energy ray curable adhesive, for example, an optical radical curable adhesive can be used. When using an active energy ray curing type adhesive of an optical radical curing type as an ultraviolet curing type, the adhesive contains a radical polymerizable compound and a photopolymerization initiator.

The method of applying the adhesive is appropriately selected depending on the viscosity of the adhesive and the target thickness. Examples of the coating method include a reverse coater, a gravure coater (direct, reverse or offset), a bar reverse coater, a roll coater, a die coater, a bar coater, a rod coater, and the like. In addition, methods such as a dipping method can be appropriately used for coating.

In addition, when using a water-based adhesive or the like, the coating of the adhesive is preferably performed so that the thickness of the finally formed adhesive layer is 30 to 300 nm, more preferably 60 to 150 nm. On the other hand, when using an active energy ray curable adhesive, it is preferable to implement so that the thickness of the said adhesive layer may be set to 0.2-20 micrometers.

Moreover, in lamination|stacking of a polarizer and a transparent protective film, an easily bonding layer can be provided between a transparent protective film and an adhesive bond layer. The easily bonding layer can be formed of, for example, various resins having a polyester skeleton, a polyether skeleton, a polycarbonate skeleton, a polyurethane skeleton, a silicone-based skeleton, a polyamide skeleton, a polyimide skeleton, a polyvinyl alcohol skeleton, and the like. These polymer resins can be used individually by 1 type or in combination of 2 or more types. Moreover, you may add other additives to formation of an easily bonding layer. Specifically, stabilizers such as tackifiers, ultraviolet absorbers, antioxidants, and heat-resistant stabilizers may also be used.

The said adhesive layer is formed from an adhesive (adhesive composition). Various adhesives may be used as the adhesive, and examples thereof include rubber-based adhesives, acrylic adhesives, silicone-based adhesives, urethane-based adhesives, vinylalkyl ether-based adhesives, polyvinylpyrrolidone-based adhesives, polyacrylamide-based adhesives, cellulose-based adhesives, and the like. can be heard An adhesive base polymer is selected according to the type of the adhesive. Among the above-mentioned pressure-sensitive adhesives, acrylic pressure-sensitive adhesives are preferably used because they are excellent in optical transparency, appropriately exhibit adhesive properties such as wettability, cohesiveness, and adhesiveness, and are excellent in weather resistance and heat resistance.

The said undercoat layer (primer layer) is formed in order to improve the adhesiveness of a polarizer and a transparent protective film. The material constituting the primer layer is not particularly limited as long as it is a material that exhibits strong adhesion to both the base film and the polyvinyl alcohol-based resin layer to some extent. For example, a thermoplastic resin having excellent transparency, thermal stability, stretchability, and the like is used. Examples of the thermoplastic resin include acrylic resins, polyolefin resins, polyester resins, polyvinyl alcohol resins, or mixtures thereof.

<First adhesive layer>

A structure in which a first pressure-sensitive adhesive layer is laminated on at least one side of the polarizing film may be used, and other optical members (e.g., phase difference films, liquid crystal displays, etc.) and the like can be laminated. Moreover, it is also possible to laminate|stack the 1st adhesive layer directly on the said undercoat layer laminated|stacked on the polarizer. An adhesive can be used appropriately for formation of the first pressure sensitive adhesive layer, and there is no particular restriction on the type thereof. Examples of the adhesive include rubber-based adhesives, acrylic-based adhesives, silicone-based adhesives, urethane-based adhesives, vinylalkyl ether-based adhesives, polyvinyl alcohol-based adhesives, polyvinylpyrrolidone-based adhesives, polyacrylamide-based adhesives, and cellulose-based adhesives. Among these pressure-sensitive adhesives, those having excellent optical transparency, appropriate wettability, cohesiveness, and adhesion properties, and excellent weatherability, heat resistance, and the like are preferably used. As one exhibiting such characteristics, an acrylic pressure-sensitive adhesive is preferably used.

As a method of forming the first pressure-sensitive adhesive layer, for example, a method of applying the pressure-sensitive adhesive to a separator subjected to peeling treatment, drying and removing a polymerization solvent, and then transferring the pressure-sensitive adhesive layer to a polarizing film, or a polarizing film. It is prepared by a method of applying the pressure-sensitive adhesive to a polarizer and drying and removing a polymerization solvent to form an adhesive layer on the polarizer. In addition, in application of an adhesive, you may newly add 1 or more types of solvents other than a polymerization solvent suitably. As the separator subjected to the peeling treatment, a silicon separator is preferably used.

In the step of applying and drying the pressure-sensitive adhesive of the present invention on such a separator to form a pressure-sensitive adhesive layer, as a method of drying the pressure-sensitive adhesive, an appropriate method may be employed depending on the purpose. Preferably, a method of overheating and drying the coating film is used. The heating and drying temperature is preferably 40 to 200°C, more preferably 50 to 180°C, and particularly preferably 70 to 170°C. By setting the heating temperature within the above range, a pressure-sensitive adhesive having excellent adhesive properties can be obtained.

As a method of forming the first pressure-sensitive adhesive layer, various methods are used. Specifically, for example, roll coat, kiss roll coat, gravure coat, reverse coat, roll brush, spray coat, dip roll coat, bar coat, knife coat, air knife coat, curtain coat, lip coat, die coater, etc. Methods, such as the extrusion coating method by, are mentioned.

The thickness of the first pressure-sensitive adhesive layer is preferably 2 to 50 μm, more preferably 2 to 40 μm, still more preferably 5 to 35 μm.

The separator can protect the adhesive surface of the first pressure-sensitive adhesive layer until it is put into practical use. Examples of materials constituting the separator include plastic films such as polyethylene, polypropylene, polyethylene terephthalate, and polyester films, porous materials such as paper, cloth, and nonwoven fabric, nets, foam sheets, and metal foils, and these Appropriate thin paper bodies, such as a laminate body, etc. are mentioned, However, A plastic film is used suitably from the point which is excellent in surface smoothness. The plastic film is not particularly limited as long as it can protect the pressure-sensitive adhesive layer, and examples include a polyethylene film, a polypropylene film, a polybutene film, a polybutadiene film, a polymethylpentene film, a polyvinyl chloride film, A vinyl chloride copolymer film, a polyethylene terephthalate film, a polybutylene terephthalate film, a polyurethane film, an ethylene-vinyl acetate copolymer film, etc. are mentioned.

If necessary, the separator may also be subjected to release and antifouling treatment using a silicone-based, fluorine-based, long-chain alkyl-based or fatty acid amide-based release agent, silica powder, or the like, or antistatic treatment such as coating, kneading, or vapor deposition. . In particular, peelability from the first pressure-sensitive adhesive layer can be further improved by appropriately performing a peeling treatment such as silicone treatment, long-chain alkyl treatment, or fluorine treatment on the surface of the release film.

As for the thickness of the said separator, 5-50 micrometers are preferable normally, More preferably, it is 20-40 micrometers.

Example

Hereinafter, examples and the like specifically showing the constitution and effects of the present invention will be described, but the present invention is not limited thereto. In addition, about the compounding content and characteristic evaluation in Examples etc., measurement was performed as follows. Table 1 shows the physical property values of the (meth)acrylic polymer used in the pressure-sensitive adhesive composition, Table 2 shows the blending ratio of the pressure-sensitive adhesive composition, and Table 3 shows the evaluation results of the properties of the surface protection sheet.

<Methods for measuring polymer properties>

Below, a specific method for measuring physical properties of a polymer is described.

<Measurement of weight average molecular weight (Mw)>

The weight average molecular weight (Mw) of the (meth)acrylic polymer used in the present invention was measured using a GPC device (HLC-8220GPC) manufactured by Tosoh Corporation. Measurement conditions are as follows.

Sample concentration: 0.2% by mass (THF solution)

Sample injection amount: 10 μl

Eluent: THF

Flow rate: 0.6 ml/min

Measurement temperature: 40 ℃

column:

Sample column：TSKguardcolumn SuperHZ-H (1 piece) + TSKgel SuperHZM-H (2 pieces)

Reference column：TSKgel SuperH-RC (1ea)

Detector: Differential refractometer (RI)

In addition, the weight average molecular weight (Mw) was calculated|required in terms of polystyrene.

<Theoretical value of glass transition temperature (Tg)>

The glass transition temperature Tg (°C) was determined by the following equation using the values in the literature below as the glass transition temperature Tgn (°C) of the homopolymer of each monomer.

Formula: 1/(Tg + 273) = Σ[Wn/(Tgn + 273)]

[Wherein, Tg (° C.) is the glass transition temperature of the copolymer, Wn (-) is the mass fraction of each monomer, Tgn (° C.) is the glass transition temperature of the homopolymer of each monomer, and n is the type of each monomer. indicate.]

Literature value:

2-ethylhexyl acrylate (2EHA): -70 ° C

2-hydroxyethyl acrylate (HEA): -15 ° C

4-Hydroxybutylacrylate (4HBA): -32°C

Acrylic acid (AA): 106 ℃

In addition, reference was made to "Synthesis/Design of Acrylic Resins and Development of Trustworthiness" (published by Central Management Development Center Publishing Department) and "Polymer Handbook" (John Wiley & Sons) as literature values.

<Manufacture of optical member (polarizing film)>

(Manufacture of polarizer)

An amorphous isophthalic acid copolymerized polyethylene terephthalate (IPA copolymerized PET) film with a water absorption of 0.75% and a Tg of 75°C (thickness: 100 μm) was corona treated on one side of the substrate, and polyvinyl alcohol (PVA , degree of polymerization 4200, degree of saponification 99.2 mol%) and acetoacetyl-modified PVA (degree of polymerization 1200, degree of acetoacetyl modification 4.6%, degree of saponification 99.0 mol% or more, manufactured by Nippon Synthetic Chemical Industry Co., Ltd., trade name "Gosephamer Z200") 9: An aqueous solution containing at a ratio of 1 was applied and dried at 25°C to form a PVA-based resin layer having a thickness of 11 µm to prepare a laminate. The obtained layered product was uniaxially stretched at the free end 2.0 times in the longitudinal direction (longitudinal direction) between rolls having different circumferential speeds in a 120°C oven (air assisted stretching treatment).

Next, the laminate was immersed in an insolubilization bath (boric acid aqueous solution obtained by blending 4 parts by mass of boric acid with respect to 100 parts by mass of water) at a liquid temperature of 30°C for 30 seconds (insolubilization treatment).

Then, it was immersed in the dyeing|dyeing bath of 30 degreeC liquid temperature, adjusting iodine concentration and immersion time so that a polarizing film might become predetermined transmittance|permeability. In this example, 0.2 parts by mass of iodine and 1.0 parts by mass of potassium iodide were blended with respect to 100 parts by mass of water, and immersed in an iodine aqueous solution for 60 seconds (dyeing treatment).

Next, it was immersed in a crosslinking bath (boric acid aqueous solution obtained by blending 3 parts by mass of potassium iodide and blending 3 parts by mass of boric acid with respect to 100 parts by mass of water) at a solution temperature of 30°C for 30 seconds (crosslinking treatment).

After that, the layered product was immersed in an aqueous solution of boric acid at a liquid temperature of 70°C (an aqueous solution obtained by blending 4 parts by mass of boric acid and blending 5 parts by mass of potassium iodide with respect to 100 parts by mass of water) between rolls having different circumferential speeds. Uniaxial stretching was performed so that the total stretching ratio in the direction (longitudinal direction) was 5.5 times (underwater stretching treatment).

Thereafter, the laminate was immersed in a washing bath (an aqueous solution obtained by blending 4 parts by mass of potassium iodide with respect to 100 parts by mass of water) at a liquid temperature of 30°C (washing treatment). By the above, the optical film layered product containing the 5-micrometer-thick polarizer (PVA system resin layer) was obtained.

(formation of adhesive layer)

In a reaction vessel equipped with a cooling pipe, a nitrogen inlet pipe, a thermometer and a stirring device, 100 parts of butyl acrylate, 3 parts of acrylic acid, 0.1 part of 2-hydroxyethyl acrylate and 0.3 part of 2,2'-azobisisobutyronitrile were mixed with acetic acid. A solution was prepared by adding with ethyl. Next, it stirred while blowing nitrogen gas into this solution, and it was made to react at 55 degreeC for 8 hours, and the solution containing an acrylic polymer with a weight average molecular weight of 2.2 million was obtained. Furthermore, ethyl acetate was added to the solution containing this acrylic polymer to obtain an acrylic polymer solution in which the solid content concentration was adjusted to 30%.

Based on 100 parts of the solid content of the acrylic polymer solution, as a crosslinking agent, a crosslinking agent mainly composed of a compound having an isocyanate group (manufactured by Tosoh Corporation, trade name "Colonate L") as a crosslinking agent, and 0.075 part of γ-glycy as a silane coupling agent Doxypropyltrimethoxysilane (manufactured by Shin-Etsu Chemical Industry Co., Ltd., trade name "KMB-403") was blended in this order to prepare an adhesive solution. The pressure-sensitive adhesive solution was applied to the surface of a release sheet (separator) made of a polyethylene terephthalate film (thickness: 38 μm) subjected to peeling treatment to a thickness after drying of 25 μm, and dried to form an adhesive layer.

(Manufacture of polarizing film 1)

A 40 μm-thick triacetyl cellulose (TAC) film (trade name “TAC film KC4UY” manufactured by Konica Minolta Opto) was bonded to the polarizer side of the optical film laminate through a vinyl alcohol-based adhesive. Next, the amorphous IPA copolymerized PET film substrate was peeled off, the pressure-sensitive adhesive layer was bonded to the peeled surface, and polarizing film 1 was produced.

(Manufacture of polarizing film 2)

An acrylic hard coat resin (Unidic 17-813, manufactured by Dainippon Ink and Chemicals Co., Ltd.) was dispersed in isopropyl alcohol, and a coating solution having a solid content concentration of 25% by weight was coated with a 40 μm thick triacetyl cellulose (TAC) film (Konica A TAC film in which a hard coat layer having a thickness of 7 μm was formed was prepared by applying to one side of Minolta Opto (trade name “TAC film KC4UY”), drying at 80° C. for 2 minutes, and further UV treatment.

Next, the TAC film on which the hard coat layer was formed (the surface opposite to the surface on which the hard coat layer was formed) was bonded to the polarizer side of the optical film laminate through a vinyl alcohol-based adhesive. . Next, the amorphous IPA copolymerized PET film substrate was peeled off, and the pressure-sensitive adhesive layer was bonded to the peeled surface to prepare a polarizing film 2.

<Preparation method>

Below, a method for synthesizing a specific (meth)acrylic polymer and a method for preparing an adhesive composition and the like are described.

<Preparation of (meth)acrylic polymer 1 solution>

95 parts by mass of 2-ethylhexyl acrylate (2EHA), 5 parts by mass of 2-hydroxyethyl acrylate (HEA), 2 as a polymerization initiator, were added to a four-necked flask equipped with a stirring blade, thermometer, nitrogen gas inlet pipe, and condenser. 0.2 parts by mass of 2'-azobisisobutyronitrile and 150 parts by mass of ethyl acetate were added, nitrogen gas was introduced while stirring gently, and the liquid temperature in the flask was maintained at around 65°C, and polymerization was carried out for 6 hours, ( A meth)acrylic polymer 1 solution (40% by mass) was prepared. The weight average molecular weight (Mw) of the said (meth)acrylic polymer 1 was 550,000, and the glass transition temperature (Tg) was -68 degreeC.

<Preparation of (meth)acrylic polymer 2 solution>

95 parts by mass of 2-ethylhexyl acrylate (2EHA), 4.9 parts by mass of 2-hydroxyethyl acrylate (HEA), and 0.1 part by mass of acrylic acid (AA) were placed in a four-neck flask equipped with a stirring blade, a thermometer, a nitrogen gas inlet pipe, and a condenser. 0.2 parts by mass of 2,2'-azobisisobutyronitrile and 150 parts by mass of ethyl acetate were introduced as parts by mass and polymerization initiators, nitrogen gas was introduced while stirring gently, the liquid temperature in the flask was maintained at around 65°C, and A polymerization reaction was carried out over time to prepare a (meth)acrylic polymer 2 solution (40% by mass). The weight average molecular weight (Mw) of the (meth)acrylic polymer 2 was 550,000, and the glass transition temperature (Tg) was -68°C.

<Preparation of (meth)acrylic polymer 3 solution>

98.5 parts by mass of 2-ethylhexyl acrylate (2EHA), 1.5 parts by mass of 4-hydroxybutyl acrylate (4HBA), and 0.006 parts by mass of acrylic acid (AA) were placed in a four-neck flask equipped with a stirring blade, a thermometer, a nitrogen gas inlet pipe, and a condenser. 0.2 parts by mass of 2,2'-azobisisobutyronitrile and 150 parts by mass of ethyl acetate were introduced as parts by mass and polymerization initiators, nitrogen gas was introduced while stirring gently, the liquid temperature in the flask was maintained at around 65°C, and A polymerization reaction was carried out over time to prepare a (meth)acrylic polymer 2 solution (40% by mass). The weight average molecular weight (Mw) of the (meth)acrylic polymer 3 was 480,000, and the glass transition temperature (Tg) was -70°C.

<Preparation of (meth)acrylic polymer 4 solution>

90.9 parts by mass of 2-ethylhexyl acrylate (2EHA), 9.1 parts by mass of 4-hydroxybutyl acrylate (4HBA), 0.02 parts by mass of acrylic acid (AA) were placed in a four-necked flask equipped with a stirring blade, thermometer, nitrogen gas inlet pipe, and condenser. 0.2 parts by mass of 2,2'-azobisisobutyronitrile and 150 parts by mass of ethyl acetate were introduced as parts by mass and polymerization initiators, nitrogen gas was introduced while stirring gently, the liquid temperature in the flask was maintained at around 65°C, and A polymerization reaction was carried out over time to prepare a (meth)acrylic polymer 2 solution (40% by mass). The weight average molecular weight (Mw) of the (meth)acrylic polymer 3 was 540,000, and the glass transition temperature (Tg) was -67°C.

<Preparation of solution 1 for antistatic layer>

Polyester resin Vironal MD-1480 (25% aqueous solution, manufactured by Toyobo Co., Ltd.) as a binder, polyanilinesulfonic acid (aquapass, weight average molecular weight: 40,000, manufactured by Mitsubishi Rayon Co., Ltd.) as a conductive polymer, and diisopropylamine as a crosslinking agent. Isocyanurate of hexamethylene diisocyanate, as a lubricant, oleic acid amide in a mixed solvent of water/ethanol (1/3), 100 parts by mass of a binder in solid amount, 75 parts by mass of conductive polymer in solid amount, crosslinking agent In terms of solid content, 10 parts by mass and 30 parts by mass of lubricant were added in terms of solid content, stirred for about 20 minutes, and thoroughly mixed. In this way, solution 1 for an antistatic layer having an NV of about 0.4% by mass was prepared.

<Preparation of solution 2 for antistatic layer>

As a binder, 100 parts by mass of polyester resin Vironal MD-1480 (25% aqueous solution, manufactured by Toyobo Co., Ltd.) in solid content, and as a conductive polymer, poly(3,4-ethylenedioxythiophene) (PEDOT)/polystyrenesulfonic acid 100 parts by mass of (PSS) (manufactured by Baytron P, H, C, Starck) in solid content, 10 parts by mass in solid content of an isocyanurate form of hexamethylene diisocyanate blocked with diisopropylamine as a crosslinking agent, was added to a mixed solvent of water/ethanol (1/1), and stirred for about 20 minutes to thoroughly mix. In this way, solution 2 for an antistatic layer having an NV of about 0.4% was prepared.

<Manufacture of support film 1 with antistatic layer>

The antistatic layer solution 1 was applied to a transparent polyethylene terephthalate (PET) film having a thickness of 38 μm, a width of 30 cm and a length of 40 cm, which was corona treated on one side, and the antistatic layer solution 1 was applied to a thickness of 30 nm after drying. . By heating and drying this coating material at 130 degreeC for 1 minute, the support film 1 with an antistatic layer which has an antistatic layer on one side of a PET film was manufactured.

<Manufacture of support film 2 with antistatic layer>

The antistatic layer solution 2 was applied to a transparent polyethylene terephthalate (PET) film having a thickness of 38 μm, a width of 30 cm and a length of 40 cm, which was corona treated on one side, and the antistatic layer solution 2 was applied to a thickness of 30 nm after drying. . An antistatic layer-attached support film 2 having an antistatic layer on one side of a PET film was prepared by heating and drying this coated material at 130°C for 1 minute.

<Example 1>

<Manufacture of surface protection sheet>

The (meth)acrylic polymer 1 solution (40% by mass) was diluted to 20% by mass with ethyl acetate, and 1-ethyl-3-methyl as the ionic compound 1 was added to 500 parts by mass (100 parts by mass of solid content) of this solution. 0.5 parts by mass of midazolium bis(fluorosulfonyl)imide, as a compound having an alkylene oxide group, an organopolysiloxane having an oxyalkylene chain (KF-6004, manufactured by Shin-Etsu Chemical Co., Ltd.) 0.5 parts by mass, aliphatic as a crosslinking agent 3 parts by mass (solid content: 3 parts by mass) of an isocyanurate of hexamethylene diisocyanate, which is an isocyanate compound (Colonate HX, manufactured by Tosoh Corporation), as a crosslinking catalyst, dibutyltin dilaurate (1% by mass ethyl acetate solution) 3 parts by mass (0.03 parts by mass of solid content) were added, mixing and stirring were performed, and adhesive composition 1 (solution) was prepared.

The pressure-sensitive adhesive composition 1 (solution) was applied to the other surface without the antistatic layer of the antistatic layer-attached support film 1, and heated at 130 ° C. for 1 minute to form a pressure-sensitive adhesive layer having a thickness of 15 μm. . Next, the siliconized side of a polyethylene terephthalate film (thickness: 25 μm), which is a separator that has undergone silicone treatment on one side, was bonded to the surface of the pressure-sensitive adhesive layer to prepare a surface protection sheet.

<Example 2>

<Manufacture of surface protection sheet>

The (meth)acrylic polymer solution 2 (40% by mass) was diluted to 20% by mass with ethyl acetate, and 1-ethyl-3-methyl as the ionic compound 2 was added to 500 parts by mass (100 parts by mass of solid content) of this solution. 0.5 parts by mass of midazolium bis(trifluoromethanesulfonyl)imide, 0.5 parts by mass of an organopolysiloxane having an oxyalkylene chain as a compound having an alkylene oxide group (KF-353, manufactured by Shin-Etsu Chemical Co., Ltd.), as a crosslinking agent, An isocyanurate of hexamethylene diisocyanate, which is an aliphatic isocyanate compound (Colonate HX, manufactured by Tosoh Corporation) 3 parts by mass (3 parts by mass solid content), as a crosslinking catalyst, dibutyltin dilaurate (1% by mass ethyl acetate solution ) 3 parts by mass (0.03 parts by mass of solid content) were added, mixing and stirring were performed, and adhesive composition 2 (solution) was prepared.

The pressure-sensitive adhesive composition 2 (solution) was applied to the other side without the antistatic layer of the support film 2 with the antistatic layer, and heated at 130 ° C. for 1 minute to form a pressure-sensitive adhesive layer having a thickness of 15 μm. . Next, the siliconized side of a polyethylene terephthalate film (thickness: 25 μm), which is a separator that has undergone silicone treatment on one side, was bonded to the surface of the pressure-sensitive adhesive layer to prepare a surface protection sheet.

<Examples 3 to 9>

Based on the compounding contents and compounding ratios in Table 2, a surface protective sheet was prepared in the same manner as in Example 2. In addition, the compounding quantity in a table|surface showed solid content.

<Comparative Examples 1 to 4>

Based on the blending contents and blending ratios in Table 2, a surface protection sheet was prepared in the same manner as in Example 1. In addition, the compounding quantity in a table|surface showed solid content.

Abbreviations in Table 1 and Table 2 are described below.

<monomer>

2EHA: 2-ethylhexyl acrylate (main monomer)

HEA: 2-hydroxyethyl acrylate (hydroxyl group-containing (meth)acrylic monomer)

4HBA: 4-hydroxybutyl acrylate (hydroxyl group-containing (meth)acrylic monomer)

AA: Acrylic acid ((meth)acrylic monomer containing a carboxyl group)

<Antistatic agent (onium salt)>

Ionic compound 1:1-ethyl-3-methylimidazolium bis(fluorosulfonyl)imide (melting point: -13°C)

Ionic compound 2: 1-ethyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide (melting point -15 ℃)

Ionic compound 3: 1-butyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide (melting point -4 °C)

Ionic compound 4: 1-ethyl-3-methylpyridinium bis(fluorosulfonyl)imide (melting point -6 ℃)

Ionic compound 5: 1-hexylpyridinium bis (trifluoromethanesulfonyl) imide (melting point 0 ° C)

Ionic compound 6: N-methyl-N-propylpiperidinium bis(trifluoromethanesulfonyl)imide (melting point 12°C)

Ionic compound 7: tributylmethylphosphonium bis(trifluoromethanesulfonyl)imide (melting point 16°C)

<Compound having an alkylene oxide group>

KF353: Organopolysiloxane having an oxyalkylene chain in the side chain (manufactured by Shin-Etsu Chemical Co., Ltd., trade name: KF-353)

KF6004: Organopolysiloxane having an oxyalkylene chain in a straight chain (manufactured by Shin-Etsu Chemical Co., Ltd., trade name: KF-6004)

<Fluorine-based oligomer>

F-562: Fluorine-based oligomer, weight average molecular weight 27900 (manufactured by DIC, trade name: Megafac F-562)

<Evaluation method>

Below, specific measurement and evaluation methods are described.

<Measurement of peel zone voltage in Examples 1 to 7 and Comparative Examples 1 to 4>

As shown in Fig. 1, the surface protection sheet 2 was cut to a size of 70 mm in width and 130 mm in length, and after the separator was peeled off, the acrylic plate 4 (thickness: 2 mm, width: 70 mm, length: 100 mm) was bonded to the polarizing film 1 surface (TAC surface), and pressure bonding was performed with a hand roller so that 30 mm of one-sided edge protruded.

After being allowed to stand in a low-temperature environment at 0°C for one day, a sample was set at a predetermined position as shown in FIG. 1 . The end of the protruding one side of 30 mm was fixed to an automatic winding machine (not shown), and peeling was performed at a peeling angle of 150° and a peeling speed of 30 m/min (high-speed peeling). The potential (separation band voltage: absolute value, kV) on the surface of the polarizing film generated at this time was measured with a potential meter 1 (manufactured by Shishido Electrostatic Co., model "STATIRON DZ-4") fixed at the center of the polarizing film. The measurement was performed in an environment of 23°C x 50% RH.

After attaching (leaving) the adhesive side of the pressure-sensitive adhesive layer used for the surface protection sheet to the TAC surface (polarizing film surface) for 1 day in a low temperature environment of 0 ° C., at a peeling angle of 150 ° and a peeling speed of 30 m / min. The potential (peeling band voltage: kV, absolute value) on the surface of the polarizing film generated when peeling (high-speed peeling) is preferably 0.6 kV or less, more preferably 0.5 kV or less, and still more preferably 0.4 kV or less. If the separation band voltage exceeds 0.6 kV, there is a risk of causing damage to, for example, a liquid crystal driver or the like, which is not preferable.

<Measurement of peeling band voltage in Examples 8 and 9>

As shown in Fig. 1, the surface protection sheet 2 is cut to a size of 70 mm in width and 130 mm in length, and after the separator is peeled off, the acrylic plate 4 (thickness: 2 mm, width: 70 mm, length : 100 mm) was bonded to the polarizing film 2 surface (hard coat surface), and pressure bonding was performed with a hand roller so that 30 mm of one-sided edge protruded.

After being allowed to stand in a low-temperature environment at 0°C for one day, a sample was set at a predetermined position as shown in FIG. 1 . 30 mm fixed the end of the protruding one side to an automatic winding machine (not shown), and peeled so that it might become a peeling angle of 150 degrees and a peeling speed of 30 m/min (high-speed peeling). The potential (separation band voltage: absolute value, kV) on the surface of the polarizing film generated at this time was measured with a potential meter 1 (manufactured by Shishido Electrostatic Co., model "STATIRON DZ-4") fixed at the center of the polarizing film. The measurement was performed in an environment of 23°C x 50% RH.

After the adhesive side of the pressure-sensitive adhesive layer used for the surface protection sheet was applied (leaved) on the hard coat surface for 1 day in a low temperature environment of 0 ° C., peeling at a peeling angle of 150 ° and a peeling speed of 30 m / min (high-speed peeling ) is preferably 0.6 kV or less, more preferably 0.5 kV or less, and still more preferably 0.4 kV or less. If the separation band voltage exceeds 0.6 kV, there is a risk of causing damage to, for example, a liquid crystal driver or the like, which is not preferable.

<white of liquid crystal panel)>

A surface protection sheet was bonded to the surface of the polarizing film using a hand roller. After that, it was cut into a size of 150 mm x 100 mm, the separator film was removed, and it was bonded to a liquid crystal cell to obtain a liquid crystal panel, and the panel was left to stand in a low-temperature environment at 0°C for one day. Immediately after taking out, it was placed on a backlight having a luminance of 10000 cd in an environment of 23 ° C. × 50% RH, and the surface protection film was peeled from the surface of the polarizing film at a speed of 1 m / sec to generate static electricity, thereby causing disorientation of the liquid crystal. . The recovery time (seconds) of the display defect due to the poor orientation was measured visually, and white unevenness was evaluated.

It is preferable that the recovery time of display defect is less than 30 second. White unevenness was evaluated according to the following criteria.

○: Recovery (disappearance) time less than 30 seconds

×: Recovery (disappearance) time is 30 seconds or more

According to the above evaluation method, the peeling band voltage and white unevenness of the surface protective sheet produced in a low-temperature environment of 0°C were evaluated, and the evaluation results are shown in Table 3.

From the results of Table 3, in all examples, by using an ionic compound that is an onium salt with a melting point of -4°C or less, the peel withstand voltage is 0.6 kV or less, the white unevenness dissipation time is short, and the antistatic property is I was able to confirm that it was excellent.

On the other hand, in all the comparative examples, since an ionic compound having a melting point exceeding -4°C was used, the peeling band voltage in a low-temperature environment exceeded 0.6 kV, the white unevenness dissipation time was long, and the antistatic property was excellent. Falling was confirmed. Particularly, in Comparative Examples 3 and 4 using an ionic compound having a melting point of 10 deg.

1: Potential meter
2: surface protection sheet
3: Polarizing film
4: Acrylic board
5 : Fixing table

Claims (7)

On one side of the support film, an onium salt having a melting point of -4°C or less and a polymer having a glass transition temperature of 0°C or less as a base polymer are contained, and the onium salt is a nitrogen-containing onium salt, a sulfur-containing onium salt, and , An optical member protected by a surface protection sheet having an adhesive layer formed from an adhesive composition that is at least one selected from the group consisting of phosphorus-containing onium salts,
The optical member characterized in that the said optical member is a polarizing film containing a polarizer, and the thickness of the said polarizer is 8 micrometers or less. According to claim 1,
An optical member characterized in that the pressure-sensitive adhesive composition contains a compound having an alkylene oxide group. According to claim 1,
The optical member characterized in that the polymer having a glass transition temperature of 0°C or less is a (meth)acrylic polymer having a hydroxyl group and/or a carboxyl group. delete According to any one of claims 1 to 3,
An antistatic layer is provided on a surface opposite to the pressure-sensitive adhesive layer formed on the support film, and the antistatic layer is formed from an antistatic agent composition containing polyanilines and/or polythiophenes as a conductive polymer component. An optical member characterized in that being. delete delete

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