JP7237555B2 - laminate - Google Patents

Description

The present invention relates to laminates. More particularly, it relates to a laminate resistant to electrostatic shock.

Since plastic products have high electrical insulation, static electricity is generated by contact, peeling, and friction. This static electricity causes dust to adhere to plastic products. Moreover, when the plastic product is an electronic device, the discharge of static electricity not only causes damage to the electronic device, but also poses a risk of fire or explosion.

Antistatic materials are used to prevent the generation of static electricity in plastic products. As an antistatic material, an antistatic coating agent in which a conductive polymer is dispersed in a solvent is applied to plastic products to prevent the generation of static electricity. As such a conductive polymer, a π-conjugated conductive polymer such as polyaniline or polythiophene is often used.

On the other hand, even if an antistatic material is applied, the adverse effects of static electricity cannot be completely prevented. For example, in a low-humidity environment, the human body is charged with static electricity of several thousand volts or more. When a hand touches an antistatic article in such a statically charged state, static electricity with a high voltage of several thousand volts or more is discharged all at once, and the antistatic article receives an electric shock. The conductive polymer that receives the electric shock is oxidized and deteriorates. Further, for example, when a sheet-shaped article imparted with antistatic property is in contact with another adherend, when the sheet-shaped article is peeled off from the adherend, discharge occurs due to the peeling, and the conductive polymer deteriorates due to oxidation. Conductive polymers that have deteriorated due to oxidation have reduced antistatic properties, and the effects of preventing dust from adhering and removing static electricity are diminished. Therefore, in order to ensure a high level of antistatic properties, there has been a demand for the development of an antistatic material that is resistant to deterioration due to electric shock from static electricity.

In Patent Documents 1 and 2, fine particles are blended in the antistatic layer of the laminate for the purpose of enhancing anti-glare properties, coating film lubricity, and anti-blocking properties. However, as an antistatic agent, a cationic polymer is used in Patent Document 1, and fine particles themselves are used in Patent Document 2, and the conductivity is low and the antistatic effect is not sufficient.

In Patent Document 3, fine particles are blended into a surface protective film for optical films for the purpose of enhancing antiglare properties. In Patent Document 4, a small amount of fine particles is blended as a coating film lubricant in an antistatic layer of a polarizing plate protective film containing a polythiophene-based conductive polymer. However, applications other than the anti-glare properties of fine particles and lubricants have not been investigated.

Japanese Patent Application Laid-Open No. 2008-020698 JP 2008-087434 A JP 2011-191768 A JP-A-2000-026817

An object of the present invention is to provide a laminate whose antistatic performance is less likely to deteriorate even if it receives an electric shock due to static electricity.

The present inventors have found that in an antistatic layer made of a coating composition containing an organic conductive material and fine particles, when the surface roughness of the surface not in contact with the base film is 3 nm or more, even if it receives an electric shock due to static electricity The inventors have found that deterioration of antistatic performance can be suppressed, and completed the laminate of the present invention.

That is, the present invention is a laminate having an antistatic layer on at least one surface of a base film, wherein the antistatic layer comprises an organic conductive material (a) and fine particles having an average particle size of 10 to 500 nm (b), wherein the coating composition contains 10 to 50% by weight of fine particles (b), and the antistatic layer has a surface roughness of 3 nm or more on the surface that does not come into contact with the base film. , relating to laminates.

It is preferable that the organic conductive material (a) is a conductive polymer and/or a carbon material.

The fine particles (b) are preferably inorganic fine particles and/or organic fine particles having a crosslinked structure.

The surface roughness of the surface of the antistatic layer that is not in contact with the base film is preferably 4 to 50 nm.

A haze value measured according to JIS K 7150 is preferably 5% or less.

It is preferable that the adhesive layer is arranged on the surface of the substrate film that is not in contact with the antistatic layer.

The present invention also relates to a surface protection film containing the laminate.

The laminate of the present invention can maintain its antistatic performance even if it receives an electric shock due to static electricity.

(1) Laminate The present invention is a laminate having an antistatic layer on at least one surface of a base film, wherein the antistatic layer comprises an organic conductive material (a) and an average particle size of 10 to 500 nm. The coating composition contains 10 to 50% by weight of the fine particles (b), and the antistatic layer has a surface roughness of 3 nm on the surface that is not in contact with the base film. That's it.

The laminate of the present invention has an antistatic layer on at least one surface of the base film.

Examples of materials for the base film include glass, polyethylene terephthalate (PET), polyethylene naphthalate, polyester resins such as modified polyester, polyethylene (PE) resins, polypropylene (PP) resins, polystyrene resins, cyclic olefin resins, and the like. Polyolefin resins, vinyl resins such as polyvinyl chloride and polyvinylidene chloride, polyether ether ketone (PEEK) resin, polysulfone (PSF) resin, polyether sulfone (PES) resin, polycarbonate (PC) resin, polyamide resin , polyimide resin, acrylic resin, triacetyl cellulose (TAC) resin, and the like. These materials may be used alone or in combination of two or more.

Although the thickness of the substrate film is not particularly limited, it is preferably 10 to 10000 μm, more preferably 25 to 5000 μm. Further, the total light transmittance of the base film is preferably 60% or more, more preferably 70% or more, and even more preferably 80% or more.

The antistatic layer is made of a coating composition containing an organic conductive material and fine particles having an average particle size of 10 to 500 nm.

The organic conductive material contained in the coating composition is not particularly limited, but examples thereof include conductive polymers and carbon materials because of their excellent conductivity and low humidity dependency. These organic conductive materials may be used alone or in combination of two or more.

The conductive polymer is not particularly limited, and conventionally known conductive polymers can be used. Specific examples include, for example, polythiophene, polypyrrole, polyaniline, polyacetylene, polyphenylene vinylene, polynaphthalene, derivatives thereof, and , complexes of these and dopants, and the like. These conductive polymers may be used alone or in combination of two or more.

As the conductive polymer, a conductive polymer containing at least one thiophene ring in the molecule is preferable. The reason for this is that a highly conductive molecule can easily be formed by including a thiophene ring in the molecule.

As the conductive polymer, poly(3,4-disubstituted thiophene) or a complex of poly(3,4-disubstituted thiophene) and polyanion is more preferable. This is because they are extremely excellent in electrical conductivity and chemical stability. Further, when poly(3,4-disubstituted thiophene) or a complex of poly(3,4-disubstituted thiophene) and polyanion is contained, an antistatic layer can be formed in a short time at low temperature. It can be done, and productivity will also be excellent.

Poly(3,4-disubstituted thiophene) is particularly preferably poly(3,4-dialkoxythiophene) or poly(3,4-alkylenedioxythiophene). As poly(3,4-dialkoxythiophenes) or poly(3,4-alkylenedioxythiophenes), the following formula (I):

A cationic form of polythiophene consisting of repeating structural units represented by is preferred. Here, R ¹ and R ² independently represent a hydrogen atom or a C _1-4 alkyl group, or when R ¹ and R ² are bonded, a C _1-4 alkylene group represents Examples of the C _1-4 alkyl group include, but are not limited to, methyl, ethyl, propyl, isopropyl, n-butyl, isobutyl, sec-butyl, t-butyl and the like. . Further, when R ¹ and R ² are bonded, the alkylene group for C _1-4 is not particularly limited, but examples include methylene group, 1,2-ethylene group, 1,3-propylene group, 1, 4-butylene group, 1-methyl-1,2-ethylene group, 1-ethyl-1,2-ethylene group, 1-methyl-1,3-propylene group, 2-methyl-1,3-propylene group and the like mentioned. Among these, a methylene group, a 1,2-ethylene group and a 1,3-propylene group are preferred, and a 1,2-ethylene group is more preferred. In the C _1-4 alkyl group and the C _1-4 alkylene group, part of the hydrogen atoms may be substituted. Poly(3,4-ethylenedioxythiophene) is particularly preferred as the polythiophene having a C _1-4 alkylene group.

A polyanion forms a complex with a polythiophene (derivative) by forming an ion pair, and can stably disperse the polythiophene (derivative) in water. Examples of polyanions include, but are not limited to, carboxylic acid polymers (e.g., polyacrylic acid, polymaleic acid, polymethacrylic acid, etc.), sulfonic acid polymers (e.g., polystyrenesulfonic acid, polyvinylsulfonic acid, polyisoprene sulfonic acid, etc.). These carboxylic and sulfonic acid polymers are also copolymers of vinyl carboxylic and vinyl sulfonic acids with other polymerizable monomers such as acrylates, styrene, aromatic vinyl compounds such as vinyl naphthalene. may be Among these, polystyrene sulfonic acid is particularly preferred.

Polystyrene sulfonic acid has a weight average molecular weight of more than 20,000, preferably 500,000 or less, more preferably 40,000 to 200,000. If polystyrene sulfonic acid having a molecular weight outside this range is used, the dispersion stability of the polythiophene-based conductive polymer in water may be lowered. The weight average molecular weight is a value measured by gel permeation chromatography (GPC). A Waters ultrahydrogel 500 column was used for the measurement.

The conductive polymer is preferably a composite of poly(3,4-ethylenedioxythiophene) and polystyrenesulfonic acid, since it has particularly excellent transparency and conductivity.

The conductive polymer is a composite of poly(3,4-ethylenedioxythiophene) and polystyrenesulfonic acid, and more preferably has a conductivity of 0.01 S/cm or more. The reason for this is that a coating composition containing such a conductive polymer is particularly excellent in transparency and conductivity when formed into a transparent conductive film.

Carbon materials are not particularly limited, and examples thereof include carbon nanotubes, graphene, and fullerene. These carbon materials may be used alone or in combination of two or more.

The content of the organic conductive material in the coating composition is not particularly limited. ² is preferable, and an amount of 0.1 to 10.0 mg/m ² is more preferable. If it is less than 0.01 mg/m ² , the proportion of the conductive polymer present in the antistatic layer is reduced, and sufficient conductivity of the antistatic layer may not be ensured. If it exceeds ² , the proportion of the conductive polymer in the antistatic layer increases, which may adversely affect the strength and film-forming properties of the coating film. When a carbon material is used as the organic conductive material, the amount of the antistatic layer is preferably 0.01 to 50.0 mg/m ² , more preferably 0.1 to 10.0 mg/m ² . more preferred.

In addition to the organic conductive material, the coating composition contains a binder, a conductivity improver, a solvent, a cross-linking agent, a catalyst, a surfactant and/or a leveling agent, a water-soluble antioxidant, an antifoaming agent, a rheology control agent, It may contain a neutralizing agent, a thickening agent, and the like.

Although the binder is not particularly limited, it is preferably at least one selected from the group consisting of polyester resins, acrylic resins, polyurethanes, epoxy resins, alkoxysilane oligomers, polyolefin resins, and melamine resins. The reason for this is that the compatibility with components such as organic conductive materials is high, and the antistatic layer formed using the coating composition containing these binders has good affinity for the substrate, and the film defect part can be effectively made invisible. Also, antistatic layers formed using coating compositions containing these binders have good hardness and chemical resistance. These binders may be used alone or in combination of two or more.

The polyester resin is not particularly limited as long as it is a polymer compound obtained by polycondensation of a compound having two or more carboxyl groups in the molecule and a compound having two or more hydroxyl groups, such as polyethylene. Examples include terephthalate, polytrimethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, polybutylene naphthalate and the like. These may be used independently and may use 2 or more types together.

Examples of acrylic resins include, but are not particularly limited to, (meth)acrylic resins, vinyl ester resins, and the like. These acrylic resins may be, for example, polymers containing, as constituent monomers, polymerizable monomers having acid groups such as carboxyl groups, acid anhydride groups, sulfonic acid groups, and phosphoric acid groups. and a copolymer of a polymerizable monomer having an acid group and a copolymerizable monomer. These may be used independently and may use 2 or more types together.

The (meth)acrylic resin may be polymerized with a copolymerizable monomer as long as it contains a (meth)acrylic monomer as a main constituent monomer (for example, 50 mol % or more). At least one of the (meth)acrylic monomer and the copolymerizable monomer should have an acid group.

Examples of (meth)acrylic resins include (meth)acrylic monomers having an acid group [(meth)acrylic acid, sulfoalkyl (meth)acrylate, sulfonic acid group-containing (meth)acrylamide, etc.] or Polymers, (meth)acrylic monomers optionally having an acid group, and other polymerizable monomers having an acid group [other polymerizable carboxylic acids, polymerizable polycarboxylic acids or anhydrides , vinyl aromatic sulfonic acid, etc.] and/or a copolymer with a copolymerizable monomer [e.g., (meth)acrylic acid alkyl ester, glycidyl (meth)acrylate, (meth)acrylonitrile, aromatic vinyl monomer, etc.] Polymers, other polymeric monomers having an acid group and (meth)acrylic copolymerizable monomers [e.g., (meth)acrylic acid alkyl esters, hydroxyalkyl (meth)acrylates, glycidyl (meth)acrylates, (meth)acrylonitrile, etc.], rosin-modified urethane acrylate, special modified acrylic resin, urethane acrylate, epoxy acrylate, urethane acrylate emulsion, and the like.

Among these (meth)acrylic resins, (meth)acrylic acid-(meth)acrylic acid ester polymer (acrylic acid-methyl methacrylate copolymer, etc.), (meth)acrylic acid-(meth)acrylic acid Ester-styrene copolymers (such as acrylic acid-methyl methacrylate-styrene copolymers) are preferred.

The polyurethane is not particularly limited as long as it is a polymer compound obtained by copolymerizing a compound having an isocyanate group and a compound having a hydroxyl group. Examples include ester/ether polyurethane, ether polyurethane, polyester polyurethane, Examples include carbonate-based polyurethanes and acrylic-based polyurethanes. These may be used independently and may use 2 or more types together.

Although the epoxy resin is not particularly limited, for example, bisphenol A type, bisphenol F type, phenol novolak type, polyfunctional type having many benzene rings, tetrakis(hydroxyphenyl)ethane type or tris(hydroxyphenyl)methane type. , biphenyl type, triphenolmethane type, naphthalene type, orthonovolak type, dicyclopentadiene type, aminophenol type, alicyclic epoxy resins, silicone epoxy resins, and the like. These may be used independently and may use 2 or more types together.

The alkoxysilane oligomer is, for example, a high-molecular-weight alkoxysilane formed by condensation of alkoxysilane monomers represented by the following formula (II), and a siloxane bond (Si—O—Si). Examples include oligomers having one or more in one molecule.
_SiR4 (II)
(Wherein, R is hydrogen, a hydroxyl group, an alkoxy group having 1 to 4 carbon atoms, an alkyl group which may have a substituent, a phenyl group which may have a substituent. at least one of which is an alkoxy group having 1 to 4 carbon atoms or a hydroxyl group)

The structure of the alkoxysilane oligomer is not particularly limited, and may be linear or branched. As the alkoxysilane oligomer, the compound represented by the formula (II) may be used alone, or two or more of them may be used in combination. Although the weight average molecular weight of the alkoxysilane oligomer is not particularly limited, it is preferably greater than 152 and 4000 or less, more preferably 500 to 2500. Here, the weight average molecular weight is a value measured by gel permeation chromatography (GPC).

Examples of polyolefin resins include, but are not limited to, polyethylene, polypropylene, chlorinated polypropylene, maleic anhydride-modified polypropylene, and maleic anhydride-modified chlorinated polypropylene. These may be used independently and may use 2 or more types together.

When the coating composition contains a binder, its content is not particularly limited, but it is preferably 0.1 to 1000 parts by weight, and 5 to 500 parts by weight based on 100 parts by weight of the conductive material. It is more preferable to have If the binder content is less than 0.1 parts by weight, the strength of the antistatic layer may become weak, while if it exceeds 1000 parts by weight, the proportion of the conductive material in the antistatic layer is relatively low. As a result, the conductivity of the antistatic layer may not be sufficiently ensured.

When the coating composition contains a conductivity improver, the conductivity improver is not particularly limited, but examples include amides such as N-methylformamide, N,N-dimethylformamide, γ-butyrolactone and N-methylpyrrolidone. Compound; ethylene glycol, diethylene glycol, propylene glycol, trimethylene glycol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, neopentyl glycol, catechol, cyclohexanediol, cyclohexanedimethanol, glycerin, hydroxyl group-containing compounds such as diethylene glycol monoethyl ether and propylene glycol monomethyl ether; carbonyl group-containing compounds such as isophorone, propylene carbonate, cyclohexanone, acetylacetone, ethyl acetate, ethyl acetoacetate, methyl orthoacetate and ethyl orthoformate; compounds having a sulfo group; These may be used alone or in combination of two or more.

The solvent is not particularly limited, and examples include water; alcohols such as methanol, ethanol, 2-propanol and 1-propanol; ethylene glycols such as ethylene glycol, diethylene glycol, triethylene glycol and tetraethylene glycol; ethylene glycol monomethyl Ether, glycol ethers such as diethylene glycol monomethyl ether, ethylene glycol diethyl ether, and diethylene glycol dimethyl ether; glycol ether acetates such as ethylene glycol monoethyl ether acetate, diethylene glycol monoethyl ether acetate, and diethylene glycol monobutyl ether acetate; propylene glycol, dipropylene glycol, Propylene glycols such as tripropylene glycol; Propylene glycol ethers such as propylene glycol monomethyl ether, propylene glycol monoethyl ether, dipropylene glycol monomethyl ether, propylene glycol dimethyl ether, and propylene glycol diethyl ether; Propylene glycols such as propylene glycol monomethyl ether acetate Ether acetates; Ethers such as diethyl ether, diisopropyl ether, methyl-t-butyl ether, tetrahydrofuran; Ketones such as acetone, methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone; Toluene, xylene (o-, m-, or p-xylene ), hydrocarbons such as hexane and heptane; esters such as ethyl acetate and butyl acetate; halogens; acetonitrile; A solvent etc. are mentioned. These solvents may be used alone, or two or more of them may be used in combination.

The solvent preferably does not remain in the antistatic layer formed using the coating composition. In the present specification, there is no particular distinction between a material that completely dissolves all components of the coating composition (i.e., "solvent") and a material that disperses insoluble components (i.e., "dispersion medium"). , both are described as "solvent".

By adding a cross-linking agent, the thermosetting binder resin can be cross-linked and the antistatic performance can be improved. Examples of the cross-linking agent include, but are not limited to, melamine-based, polycarbodiimide-based, polyoxazoline-based, polyepoxy-based, polyisocyanate-based, and polyacrylate-based cross-linking agents. These cross-linking agents may be used alone or in combination of two or more.

When the coating composition contains a cross-linking agent, its content is not particularly limited, but it is preferably 30% by weight or less, more preferably 20% by weight or less in the coating composition.

When the coating composition contains a thermosetting binder resin and a cross-linking agent, the catalyst for cross-linking the thermosetting binder resin is not particularly limited, and examples thereof include photopolymerization initiators and thermal polymerization initiators. be done.

By blending a surfactant and / or a leveling agent in the coating composition, the leveling property of the coating composition can be improved, and a uniform antistatic layer can be formed by using such a coating composition. can be done.

The surfactant is not particularly limited as long as it has an effect of improving leveling properties, and specific examples thereof include, for example, polyether-modified polydimethylsiloxane, polyether-modified siloxane, and polyether ester-modified hydroxyl group-containing polydimethylsiloxane. , polyether-modified acrylic group-containing polydimethylsiloxane, polyester-modified acrylic group-containing polydimethylsiloxane, perfluoropolydimethylsiloxane, perfluoropolyether-modified polydimethylsiloxane, perfluoropolyester-modified polydimethylsiloxane and other siloxane-based compounds; perfluoro Fluorine compounds such as alkylcarboxylic acids; Polyether compounds such as polyoxyethylene alkylphenyl ether; Carboxylic acids such as coconut oil fatty acid amine salts; ester compounds such as acid esters; sulfonate compounds such as alkylarylsulfonic acid amine salts and dioctyl sodium sulfosuccinate; phosphate compounds such as sodium lauryl phosphate; amide compounds such as coconut oil fatty acid ethanolamide; etc. These surfactants may be used alone or in combination of two or more. Among these, siloxane-based compounds and fluorine-based compounds are preferable because they significantly improve the leveling property.

The leveling agent is not particularly limited. siloxane-based compounds such as dimethylsiloxane, perfluoropolydimethylsiloxane, perfluoropolyether-modified polydimethylsiloxane, and perfluoropolyether-modified polydimethylsiloxane; fluorine-based compounds such as perfluoroalkylcarboxylic acids and perfluoroalkylpolyoxyethylene ethanol; Polyether compounds such as polyoxyethylene alkylphenyl ether, propylene oxide polymer, and ethylene oxide polymer; carboxylic acids such as coconut oil fatty acid amine salts and gum rosin; castor oil sulfates, phosphoric acid esters, alkyl ether sulfates, sorbitan Ester compounds such as fatty acid esters, sulfonic acid esters, and succinic acid esters; sulfonate compounds such as alkylarylsulfonic acid amine salts and dioctyl sodium sulfosuccinate; phosphate compounds such as sodium lauryl phosphate; coconut oil fatty acid ethanolamides amide compounds such as; acrylic compounds and the like. These leveling agents may be used alone or in combination of two or more. Among these leveling agents, siloxane-based compounds and fluorine-based compounds are preferable because they are excellent in dispersion stability when blended in a conductive coating composition.

When the coating composition contains a surfactant and/or leveling agent, the content thereof is not particularly limited, but is preferably 1 to 20% by weight, more preferably 5 to 10% by weight in the coating composition.

By adding a water-soluble antioxidant to the coating composition, the heat resistance and moist heat resistance of the antistatic layer can be improved. The water-soluble antioxidant is not particularly limited, and includes reducing water-soluble antioxidants, non-reducing water-soluble antioxidants, and the like.

When the coating composition contains a water-soluble antioxidant, its content is not particularly limited, but is preferably 1 to 20% by weight, more preferably 5 to 10% by weight in the coating composition.

The fine particles contained in the coating composition are not particularly limited, but examples thereof include inorganic fine particles and organic fine particles having a crosslinked structure. Although the inorganic fine particles are not particularly limited, for example, silica fine particles such as colloidal silica, hollow silica, and fumed silica, metal oxide fine particles such as titania and zirconia, and thermoplastic or thermosetting acrylic resin coated with silica. core-shell type acrylic-silica composite particles, core-shell type melamine-silica composite particles in which melamine resin is coated with silica, core-shell type acrylic-silica composite particles in which silica particles are coated with thermoplastic or thermosetting acrylic resin, Examples include core-shell type melamine-silica composite particles in which silica particles are coated with melamine resin, and organic-inorganic composite particles such as acrylic-silica composite particles in which small silica particles are supported by thermoplastic or thermosetting acrylic particles. . Although the organic fine particles are not particularly limited, examples thereof include fluororesin fine particles, acrylic resin fine particles, melamine resin fine particles, urethane rubber fine particles, and the like. These fine particles may be used alone, or two or more of them may be used in combination. It is believed that the inclusion of these fine particles locally increases the concentration of the organic conductive material in the antistatic layer, thereby improving the voltage resistance.

The average particle diameter of the microparticles is not particularly limited as long as it is 10 to 500 nm, preferably 20 to 200 nm, more preferably 50 to 150 nm. If the average particle size is less than 10 nm, it is difficult to form an antistatic layer with a thickness smaller than the particle size, and the particles cannot be exposed on the surface of the antistatic layer, so when the antistatic layer receives an electric shock due to static electricity. Antistatic performance tends to deteriorate. If it exceeds 500 nm, most of the fine particles are exposed on the surface of the antistatic layer, and the particles tend to fall off or increase the haze of the antistatic layer.

Although the volume resistivity of the fine particles is not particularly limited, it is preferably 10 ² Ω·cm or more, more preferably 10 ⁴ Ω·cm or more, and even more preferably 10 ⁶ Ω·cm or more.

The surface roughness of the surface of the antistatic layer that is not in contact with the base film is 3 nm or more. By having this surface roughness, it is possible to prevent a source of static electricity from directly contacting the antistatic layer, and to suppress deterioration of the antistatic performance even if the laminate receives an electric shock due to static electricity. Although the surface roughness is not particularly limited as long as it is 3 nm or more, it is preferably 4 nm or more, more preferably 5 nm or more. Also, the surface roughness is preferably 50 nm or less.

The thickness A (nm) of the antistatic layer is more preferably 5≦A≦200, still more preferably 10≦A≦100, and even more preferably 30≦A≦50.

The content of fine particles in the coating composition is not particularly limited as long as it is 10 to 50% by weight, preferably 10 to 30% by weight, more preferably 15 to 25% by weight. If the content is less than 10% by weight, the organic conductive material is susceptible to electric shock due to static electricity, and the antistatic performance tends to deteriorate. If the content exceeds 50% by weight, the amount of fine particles in the antistatic layer becomes excessive and the portion exposed to the surface increases, resulting in a tendency for the particles to fall off or the haze of the antistatic layer to increase.

The base film may have an adhesive layer in addition to the antistatic layer. The adhesive layer is preferably arranged on the surface of the base film that does not come into contact with the antistatic layer. The adhesive layer is formed using an adhesive composition containing an adhesive. The adhesive is not particularly limited, and conventionally known ones can be used. Specifically, for example, various (meth)acrylic acid ester monomers are homopolymerized or copolymerized (meth) Acrylic resin, ethylene/vinyl acetate copolymer resin, silicone resin such as silicone rubber having dimethylsiloxane skeleton, polyurethane resin obtained by polyaddition of polyol and polyisocyanate, natural rubber, styrene-isoprene-styrene block Copolymer (SIS block copolymer), styrene-butadiene-styrene block copolymer (SBS block copolymer), styrene-ethylene/butylene-styrene block copolymer (SEBS block copolymer), styrene-butadiene Examples thereof include rubber-based resins such as rubber, polybutadiene, polyisoprene, polyisobutylene, butyl rubber, and chloroprene rubber. Among these resins, (meth)acrylic resins, silicone resins, and polyurethane resins are preferable because they have excellent chemical stability, a high degree of freedom in chemical structure design, and easy adjustment of adhesive force. Furthermore, (meth)acrylic resins and polyurethane resins are particularly preferable in that they are excellent in transparency.

As a method for forming the adhesive layer, a conventionally known method can be used. and a method of transferring the adhesive layer to the glass substrate. In addition, the adhesive composition may contain a cross-linking agent in addition to the adhesive.

As a method for applying the pressure-sensitive adhesive composition, conventionally known methods can be used, and specific examples include roll coating, gravure coating, reverse coating, roll brushing, spray coating, air A knife coating method or the like can be used.

(2) Method for Forming Antistatic Layer The antistatic layer is formed by applying a coating composition containing an organic conductive material onto at least one surface of the substrate film. The antistatic layer may be formed by directly applying the coating composition to the substrate film, or after providing another layer such as a primer layer on the substrate in advance, and then coating it on the layer. may be formed.

The antistatic layer can be obtained by applying a coating composition onto at least one surface of the base film and then heat-treating the coating composition. The method of applying the coating composition to at least one surface of the substrate film is not particularly limited, and known methods can be used. Examples include roll coating, bar coating, dip coating, spin coating, and casting. method, die coating method, blade coating method, bar coating method, gravure coating method, curtain coating method, spray coating method, doctor coating method, slit coating method, relief (letterpress) printing method, stencil (screen) printing method, planographic (offset ) A printing method, an intaglio (gravure) printing method, a spray printing method, an inkjet printing method, a pad printing method, or the like can be used.

Before applying the coating composition onto at least one surface of the substrate film, the surface of the substrate film may be subjected to a surface treatment in advance, if necessary. Examples of surface treatment include corona treatment, plasma treatment, itro treatment, and flame treatment.

The heat treatment for forming the antistatic layer is not particularly limited and may be carried out by a known method, for example, using a fan oven, an infrared oven, a vacuum oven, or the like. If the coating composition contains a solvent, the solvent is removed by heat treatment.

The temperature condition of the heat treatment when forming the antistatic layer is not particularly limited, but is preferably 150°C or less, more preferably 50 to 140°C, and even more preferably 60 to 130°C. . If the heat treatment temperature exceeds 150° C., the material of the base material to be used is limited, and for example, it becomes impossible to use base materials generally used for transparent electrode films such as PET film, polycarbonate film and acrylic film. The treatment time of the heat treatment is not particularly limited, but is preferably 0.1 to 60 minutes, more preferably 0.5 to 30 minutes.

Although the surface resistivity of the antistatic layer is not particularly limited, it is preferably 10 ⁶ to 10 ¹⁰ Ω/□, more preferably 10 ⁷ to 10 ⁹ Ω/□.

Although the refractive index of the antistatic layer is not particularly limited, it is preferably 1.4 to 1.7, more preferably 1.5 to 1.6.

The haze value of the laminate of the present invention is not particularly limited, but is preferably 5% or less, more preferably 3% or less, and even more preferably 2% or less. If the haze value exceeds 5%, the transparency of the laminate may deteriorate. Since the haze value is preferably as small as possible, the lower limit is not particularly limited, but is, for example, 0.01%. The haze value in the present invention is measured according to JIS K7150.

(3) Surface protective film The laminate of the present invention can be suitably used as a surface protective film. A surface protective film is a film for protecting optical films such as a polarizing plate and a light guide plate from scratches and stains. For example, in the manufacture of liquid crystal panels, optical parts (films) such as polarizing plates and light guide plates are laminated and assembled with the protective film attached. It is done as it is, and then finally peeled off and discarded. When used as a surface protective film, the laminate preferably has an adhesive layer.

The adhesive strength of the surface protective film varies depending on the adherend. 25 mm is preferred.

A release paper (separator) may be adhered to the adhesive layer surface of the surface protection film, if necessary. Examples of materials for the release paper include paper and plastic films, and plastic films are preferably used because of their excellent surface smoothness. Examples of plastic films include polyethylene film, polypropylene film, polybutene film, polybutadiene film, polymethylpentene film, polyvinyl chloride film, vinyl chloride copolymer film, polyethylene terephthalate film, polybutylene terephthalate film, polyurethane film, ethylene- A vinyl acetate copolymer film and the like can be mentioned.

In the release paper, the surface in contact with the pressure-sensitive adhesive layer may be treated with a release agent such as silicone, fluorine, long-chain alkyl, or fatty acid amide release agent, silica powder, or the like.

The surface protective film can be suitably used as a surface protective film for liquid crystal panels, organic EL displays, plasma displays, polarizing plates, light diffusion sheets, lens films and the like. can be effectively protected.

The laminate of the present invention can be suitably used for polarizing plates, masking tapes, removable labels, etc., in addition to surface protective films.

EXAMPLES The present invention will be described below with reference to examples, but the present invention is not limited to the following examples. Hereinafter, "parts" or "%" mean "parts by weight" or "% by weight", respectively, unless otherwise specified.

1. Materials used 1-1. Base film/PET film (manufactured by Toray Industries, Inc., Lumirror T60)
1-2. Organic conductive material/conductive polymer PEDOT/PSS (produced in Production Example 1, solid content 1.3%)
・ Carbon nanotube (produced in Production Example 2, solid content rate 1.1%)
1-3. Fine particles / silica fine particles (manufactured by Nippon Shokubai Co., Ltd., Seahoster KE-W10, average particle size 100 nm)
・Silica fine particles-acrylic resin emulsion (manufactured by DIC Corporation, DV-961, average particle size 150 nm)
・ Silica fine particles (manufactured by Nissan Chemical Industries, Ltd., ST-XL, average particle size 50 nm)
・Acrylic resin fine particles (manufactured by Nippon Shokubai Co., Ltd., Eposter MX050W, average particle size 70 nm)
1-4. Binder resin / acrylic resin (manufactured by Toagosei Co., Ltd., Jurimer FC-80, solid content 30%, glass transition temperature 50 ° C.)
・ Polyurethane (manufactured by Daiichi Kogyo Seiyaku Co., Ltd., Superflex 830HS, solid content 35%, glass transition temperature 68 ° C.)
・ Polyester (manufactured by Toagosei Co., Ltd., Aron Melt PES-2405A30, solid content 30%, glass transition temperature 40 ° C.)
・ Melamine (manufactured by DIC Corporation, Beccamine M-3, solid content 77%)
・Urethane acrylate (UCECOAT7655 manufactured by Daicel Allnex Co., Ltd., solid content 35%)
1-5. Surfactant/silicone surfactant (manufactured by Shin-Etsu Chemical Co., Ltd., X-22-4952)
・ Fluorine-based surfactant (CAPSTONE FS-3100 manufactured by DuPont Co., Ltd.)
- Ether-based surfactant (manufactured by Clariant, Emulsogen LCN 070)
1-6. Antioxidant L (+)-ascorbic acid (manufactured by Wako Pure Chemical Industries, Ltd.)
・Gallic acid (manufactured by Wako Pure Chemical Industries, Ltd.)

2. Evaluation method 2-1. Surface Roughness The surface roughness of the antistatic layer was measured according to JIS B 0601 using a scanning probe microscope (device name: Nanocute, manufactured by SII Nanotechnology Co., Ltd.). As measurement samples, the films of Examples 1 to 12 and Comparative Example 1 were sampled and used. The measurement was performed by atmospheric measurement in DFM mode, and the measurement area was a rectangular area of 1 μm square, and the average value was obtained.

2-2. Surface resistivity The surface resistivity of the laminate was measured using a resistivity meter (Hiresta UP (MCP-HT450 type) manufactured by Mitsubishi Chemical Corporation) and a URS probe. A probe was pressed against the antistatic layer, and the surface resistivity was obtained when an applied voltage of 10 V was maintained for 10 seconds (SR1). Next, a probe was pressed against the antistatic layer, and the surface resistivity was obtained when an applied voltage of 1000 V was maintained for 60 seconds (SR2). Then, a value obtained by dividing SR2 by SR1 (SR2/SR1) was obtained as a surface resistance change rate. The surface resistance change rate indicates how much antistatic performance changes due to electric shock.

2-3. The haze immediately after production of the haze laminate was measured according to JIS K7150 using a haze computer (manufactured by Suga Test Instruments Co., Ltd., HGM-2B).

(Production Example 1) Preparation of PEDOT:PSS aqueous dispersion Using a 2000 ml three-necked glass flask equipped with a cooling tube, 92.3 parts of a polystyrene sulfonic acid aqueous solution (VERSA-TL72 manufactured by Akzo Nobel) and 3,4-ethylene were prepared. 7.1 parts of dioxythiophene (EDOT) was added to 1000 parts of deionized water to obtain a mixed solution. While stirring this mixed solution, a solution obtained by dissolving 4.0 parts of ferric sulfate and 14.8 parts of ammonium peroxodisulfate in 100 parts of ion-exchanged water was added, and the mixture was stirred at 20°C for 24 hours to perform oxidative polymerization. did Next, 15% by weight each of a cation exchange resin (Amberlite IR120B, manufactured by Organo Corporation) and an anion exchange resin (Amberlite IRA67, manufactured by Organo Corporation) were added, and the mixture was further stirred for 18 hours. The resulting reaction mixture was filtered through a glass filter, and then homogenized 10 times with a high-pressure homogenizer at 100 MPa to obtain a PEDOT:PSS aqueous dispersion.

(Production Example 2) Preparation of carbon nanotube aqueous dispersion Carbon nanotubes with an average length of 300 μm and a diameter of about 4 nm (Zeon Nano Technology Co., Ltd., ZEONANO SG101) 1 part by weight, sodium dodecyl benzene sulfonate (Wako Pure Chemical Industries, Ltd.) as a dispersant Co., Ltd.) and 989 parts by weight of pure water are placed in a glass beaker, dispersed for 30 minutes at 40 W with an ultrasonic homogenizer, and then undispersed carbon nanotubes are removed with a centrifuge at 3500 rpm. to obtain a carbon nanotube dispersion having a solid content of 1.1%.

(Examples 1 to 12, Comparative Example 1)
Each component was mixed at the weight ratio shown in Table 1 to prepare a coating composition. The coating composition was applied to one side of the base film by a bar coating method and dried at 120° C. for 2 minutes using a blower dryer to form an antistatic layer and obtain a laminate. The film thickness of the antistatic layer was adjusted to the film thickness shown in Table 1 by appropriately selecting the solid content of the coating composition and the count of the bar coater. Here, those containing a photocurable binder (urethane acrylate) were cured by drying at 120° C. for 2 minutes and then irradiating with ultraviolet rays of 500 mJ/cm ² using a metal halide lamp.

The laminates obtained in Examples 1 to 12 and Comparative Example 1 were evaluated for surface roughness, surface resistivity and haze of the antistatic layer by the methods described above. Table 1 shows the results. In the laminate of Comparative Example 1 containing no fine particles, the organic conductive material deteriorated due to electric shock, the surface resistance change rate increased to about 2800 times, and the antistatic performance could not be maintained. In the laminates of Examples 1 to 12, the rate of change in surface resistance was suppressed to about 240 times at maximum even after the electric shock, and the electrical conductivity was maintained.

Claims (7)

A method for producing a laminate having an antistatic layer,
A step of forming an antistatic layer on at least one surface of a substrate film , comprising an organic conductive material (a), fine particles (b) having an average particle size of 10 to 500 nm, and a coating composition containing water. including
The coating composition contains 10 to 50% by weight of microparticles (b),
A method for producing a laminate, wherein the surface of the antistatic layer that is not in contact with the base film has a surface roughness of 3 nm or more. 2. The method for producing a laminate according to claim 1, wherein the organic conductive material (a) is a conductive polymer and/or a carbon material. 3. The method for producing a laminate according to claim 1, wherein the fine particles (b) are inorganic fine particles and/or organic fine particles having a crosslinked structure. The method for producing a laminate according to any one of claims 1 to 3, wherein the antistatic layer has a surface roughness of 4 to 50 nm on the surface that is not in contact with the base film. 5. The method for producing a laminate according to any one of claims 1 to 4, wherein the laminate has a haze value of 5% or less as measured according to JIS K 7150. The method for producing a laminate according to any one of claims 1 to 5, further comprising the step of disposing an adhesive layer on the surface of the base film that is not in contact with the antistatic layer. The method for producing a laminate according to any one of claims 1 to 6, wherein the laminate is a surface protective film.