WO2023282232A1

WO2023282232A1 - Antistatic film and protective film

Info

Publication number: WO2023282232A1
Application number: PCT/JP2022/026615
Authority: WO
Inventors: 由佳杉本; 充晴中谷
Original assignee: 東洋紡株式会社
Priority date: 2021-07-05
Filing date: 2022-07-04
Publication date: 2023-01-12
Also published as: JPWO2023282232A1; CN117545629A; KR20240009487A

Abstract

[Problem] To provide an antistatic film and a protective film in which an antistatic layer laminated on an opposite surface from an adhesive layer of the protective film exhibits good separation properties with respect to a laminating roll. [Solution] The present invention provides a laminated polyester film having an antistatic layer on at least one side of a substrate, wherein: the antistatic layer is a layer formed by curing a composition containing a conductive polymer, a cross-linking agent (A), and a binder resin (B); the binder resin (B) is a long-chain alkyl-containing compound having at least one reactive group; and the antistatic layer satisfies (1)-(3) below: (1) the surface resistivity is 3-9 [log Ω/□]; (2) the static contact angle of water is 70-95°; and (3) the adhesion energy of water is 3.5 mJ/m2 or less.

Description

Antistatic film and protective film

The present invention relates to a laminated polyester film and a protective film obtained by laminating an adhesive layer on a laminated polyester film, and particularly to a protective film for optical members (for example, constituent members of organic EL and liquid crystal displays).

A film in which an adhesive layer is laminated on a base film is used as a protective film for each component in the manufacturing process of optical components. The protective film is attached to each member, which is an adherend, via an adhesive layer, and functions to suppress scratches and adhesion of dirt during processing and transportation of each member. An antistatic film having an antistatic layer laminated on at least one side thereof is used as the base film used for these protective films. The purpose of laminating the antistatic layer is to prevent foreign matter such as dirt and dust from adhering to the protective film and to suppress static electricity generated when the protective film is peeled off from the adherend. (See Patent Document 1)

As an antistatic film, an antistatic film containing PEDOT:PSS as an antistatic agent has been proposed. (See Patent Document 2)

WO2018/012545 JP 2018-172473 A

A protective film with an antistatic layer is used as a protective film for optical members and the like, and is particularly used in the process of processing constituent members of displays. In recent years, it has been increasingly used in the process of processing members for organic EL displays (especially OLED displays). In the process of laminating the protective film to the optical member, the adhesive layer surface of the protective film is placed in contact with the optical member, and the surface opposite to the adhesive layer laminated surface of the protective film is crimped using a laminating roll or the like. A protective film is attached.

When the lamination roll is used when laminating the protective film in this way, the interaction between the surface opposite to the adhesive layer lamination surface of the protective film and the lamination roll becomes stronger, and the separation from the protective film of the lamination roll increases. was lowered, and the protective film could not be laminated uniformly. Especially in recent years, there are cases where the adhesiveness of the adhesive is lowered to suppress the deformation of the precision parts that are fragile and easily scratched, so that the parts can be peeled off. was a particular problem.

The present invention provides an antistatic film and a protective film in which the antistatic layer laminated on the opposite side of the adhesive layer of the protective film and the lamination roll are easily separated from each other, in order to solve the above problems of the protective film.

That is, the present invention consists of the following configurations.
[1] A laminated polyester film having an antistatic layer on at least one side of a substrate,
The antistatic layer is a layer obtained by curing a composition containing a conductive polymer, a cross-linking agent (A), and a binder resin (B),
The binder resin (B) is a long-chain alkyl-containing compound having at least one reactive group,
The antistatic layer is a laminated polyester film that satisfies the following (1)-(3):
(1) Surface resistivity: 3 [logΩ/□] or more and 9 [logΩ/□] or less (2) Water contact angle: 70° or more and 95° or less (3) Water adhesion energy: 3.5 mJ/m ² or less
[2] In one aspect, the laminated polyester film has a total light transmittance of 80% or more and a haze of 3.0% or less.
[3] In one aspect, the haze of the laminated polyester film after heating at 140° C. for 10 minutes is 1.5 times or less the haze before heating.
[4] In one aspect, the antistatic layer has a change in surface resistivity after a wiping test with alcohol that is 1.3 times or less the surface resistivity before the test.
[5] In one aspect, the conductive polymer is contained in an amount of 5% by mass or more and 50% by mass or less with respect to 100% by mass of the total solid content in the antistatic layer.
[6] In one aspect, the cross-linking agent (A) and the binder resin (B) are contained in the following range with respect to 100% by mass of the total solid content in the antistatic layer, according to any one of claims 1 to 5. Laminated polyester film.
(A) 15% by mass or more and 75% by mass or less (B) 10% by mass or more and 70% by mass or less
[7] In one aspect, the binder resin (B) has a hydroxyl value of 20 mgKOH/g or more and 300 mgKOH/g or less.
[8] In one aspect, the binder resin (B) contains a carboxyl group.
[9] In one aspect, the cross-linking agent contains at least one selected from acrylamide, melamine resin, carbodiimide, oxazoline, isocyanate and aziridine.
[10] In one aspect, the laminated polyester film does not substantially contain a silicone compound.
[11] In one aspect, there is provided a protective film in which an adhesive layer is laminated on at least one surface of the laminated polyester film.
Here, the total solid content of 100 mass % is the total mass % of the conductive polymer, the cross-linking agent (A) and the binder resin (B).

According to the present invention, by providing an antistatic film in which an antistatic layer with low adhesion energy is laminated on at least one side of a polyester film, when an adhesive layer is laminated on the laminated polyester film of the present invention and used as a protective film Also, it is possible to provide a protective film that is easy to separate from the laminating roll when laminating the protective film, and that suppresses separation electrification and adhesion of foreign matter during peeling.

The laminated polyester film of the present invention (sometimes simply referred to as an antistatic film) is a polyester film having an antistatic layer laminated on at least one side thereof. Also, an adhesive layer can be laminated on one side of the antistatic film and used as a protective film.
For example, the laminated polyester film of the present invention can suppress the interaction between the surface opposite to the adhesive layer laminated surface of the protective film and the bonding roll from becoming strong when using a bonding roll when bonding the protective film. It is possible to avoid a decrease in the ability of the joint roll to separate from the protective film. Furthermore, it is possible to uniformly bond the protective film.
Especially in recent years, there are cases where the adhesiveness of the adhesive is lowered so that the deformation of the precision member that is fragile and easily scratched can be suppressed so that the member can be peeled off. It is possible to maintain good separation between the mating roll and the protective film.

The present invention will be described in detail below.

(polyester film)
The polyester film used as a substrate in the present invention is a film mainly composed of a polyester resin. Here, "a film mainly composed of a polyester resin" is a film formed from a resin composition containing 50% by mass or more of a polyester resin, and when blended with another polymer, the polyester resin is 50% by mass. % or more, and when other monomers are copolymerized, it means that 50 mol % or more of repeating structural units of polyester are contained. Preferably, the polyester film contains 90% by mass or more, more preferably 95% by mass or more, and still more preferably 100% by mass of the polyester resin in the resin composition constituting the film.

As the polyester resin, the material is not particularly limited, but a copolymer formed by polycondensation of a dicarboxylic acid component and a diol component, or a blend resin thereof can be used. Examples of dicarboxylic acid components include terephthalic acid, isophthalic acid, orthophthalic acid, 2,5-naphthalenedicarboxylic acid, 2,6-naphthalenedicarboxylic acid, 1,4-naphthalenedicarboxylic acid, 1,5-naphthalenedicarboxylic acid, diphenyl Carboxylic acid, diphenoxyethanedicarboxylic acid, diphenylsulfonecarboxylic acid, anthracenedicarboxylic acid, 1,3-cyclopentanedicarboxylic acid, 1,3-cyclohexanedicarboxylic acid, 1,4-cyclohexanedicarboxylic acid, hexahydroterephthalic acid, hexahydro isophthalic acid, malonic acid, dimethylmalonic acid, succinic acid, 3,3-diethylsuccinic acid, glutaric acid, 2,2-dimethylglutaric acid, adipic acid, 2-methyladipic acid, trimethyladipic acid, pimelic acid, azelaic acid , dimer acid, sebacic acid, suberic acid, dodecadicarboxylic acid and the like.

Examples of the diol component constituting the polyester resin include ethylene glycol, propylene glycol, hexamethylene glycol, neopentyl glycol, 1,2-cyclohexanedimethanol, 1,4-cyclohexanedimethanol, decamethylene glycol, 1,3- propanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexadiol, 2,2-bis(4-hydroxyphenyl)propane, bis(4-hydroxyphenyl)sulfone and the like.

　The dicarboxylic acid component and the diol component that constitute the polyester resin may be used alone or in combination of two or more. Further, other acid components such as trimellitic acid and other hydroxyl group components such as trimethylolpropane may be appropriately added.

Specific examples of polyester resins include polyethylene terephthalate, polypropylene terephthalate, polybutylene terephthalate, and polyethylene naphthalate. Among these, polyethylene terephthalate is preferred from the viewpoint of the balance between physical properties and cost.

In order to improve handling properties such as slipperiness and winding properties of the polyester film, the film may contain inert particles. preferably not included. When the polyester film does not contain particles, it is preferable to contain particles in the coating layer provided by in-line coating. It is preferable that the polyester film does not contain particles and the coating layer contains particles, because the transparency is improved and the appearance inspection and the like are facilitated.

The polyester film used in the present invention preferably has a haze of 3% or less. It is more preferably 2.5% or less, and may be 2.0% or less. It may be 1.5% or less, more preferably 1.0% or less, or 0.8% or less.
If it is 3% or less, it is preferable because the appearance inspection can be performed in a state where the protective film is adhered to the adherend, and it is particularly preferable when the adherend is a member for optical use.

The area average surface roughness (Sa) of the surface of the polyester film used in the present invention is preferably in the range of 1 to 40 nm, more preferably 1 to 30 nm. More preferably, it is 1 to 10 nm. The maximum protrusion height (P) on the surface of the polyester film used in the present invention is preferably 2 μm or less, more preferably 1.5 μm or less. More preferably, it is 0.8 μm or less. If Sa is 40 nm or less and P is 2 μm or less, it is preferable because there is no risk of roughening the adhesive surface when the adhesive layer is laminated and wound into a roll.

Although the thickness of the polyester film is not particularly limited in the present invention, it is preferably in the range of 12 to 188 μm. 18 to 125 μm is more preferable, and 25 to 100 μm is even more preferable. When the thickness is 12 μm or more, wrinkles are less likely to occur when the protective film is attached to an adherend, and when the thickness is 188 μm or less, it is advantageous in terms of cost.

The polyester film that serves as the base material may be a single layer or a laminate of two or more layers. In addition, if necessary, various additives can be incorporated into the film as long as the effects of the present invention are achieved. Examples of additives include antioxidants, light stabilizers, anti-gelling agents, organic wetting agents, antistatic agents, ultraviolet absorbers, and surfactants. When the film has a laminated structure, it is also preferable to contain additives depending on the function of each layer, if necessary.

A polyester film can be obtained, for example, by melt-extruding the above-mentioned polyester resin into a film, and cooling and solidifying it with a casting drum to form a film. As the polyester film of the present invention, both a non-stretched film and a stretched film can be used, but a stretched film is preferable from the viewpoint of durability such as mechanical strength and chemical resistance. When the polyester film is a stretched film, the stretching method is not particularly limited, and a vertical uniaxial stretching method, a horizontal uniaxial stretching method, a vertical and horizontal successive biaxial stretching method, a vertical and horizontal simultaneous biaxial stretching method, etc. can be employed.

The surface layer of the polyester film can be subjected to surface treatments such as an anchor coat layer, corona treatment, plasma treatment, and flame treatment in order to improve adhesion with the adhesion improving layer. When providing an anchor coat layer, in-line coating is preferable from the viewpoint of cost.

(Antistatic layer)
In the laminated polyester film (antistatic film) of the present invention, it is necessary to laminate an antistatic layer on at least one side of the polyester film. The antistatic layer may be on one side only or may be laminated on both sides. By laminating an antistatic layer, even when an adhesive layer is laminated and used as a protective film, it is possible to suppress separation electrification from the adherend and adhesion of foreign matter can be suppressed, which is preferable.

The antistatic layer is a layer obtained by curing a composition containing a conductive polymer, a cross-linking agent (A), and a binder resin (B). Such a composition may be referred to as an antistatic layer-forming composition.

The means for laminating the antistatic layer is not particularly limited, and known methods such as a coating method, a vacuum deposition method, and lamination can be used. is preferable from the viewpoint of

(Conductive polymer)
The conductive polymer in the present invention is a polymer capable of imparting antistatic properties, and may be a polymer utilizing ion conduction such as a cationic compound, a π-electron conjugated conductive polymer, or the like. It is preferable to use a π-electron conjugated conductive polymer from the viewpoint of antistatic properties under low humidity. In addition, since the π-electron conjugated conductive polymer can maintain a high level of antistatic performance without depending on the moisture in the air, it has good antistatic performance in various usage environments of the protective film. Therefore, it is preferable.
Moreover, an antistatic agent can be used in combination within a range that does not impair the effects of the conductive polymer according to the present invention. The antistatic agent may be, other than the conductive polymer in the present invention, a polymer utilizing ion conduction such as a cationic compound, a π-electron conjugated conductive polymer, a surfactant, a silicon oxide compound. , a conductive metal compound, or the like can be used.

Examples of π-electron conjugated conductive polymers include aniline polymers containing aniline or its derivatives as structural units, pyrrole polymers containing pyrrole or its derivatives as structural units, and acetylene polymers containing acetylene or its derivatives as structural units. Polymers, thiophene-based polymers containing thiophene or a derivative thereof as a structural unit, and the like can be mentioned. In order to obtain high transparency, the π-electron conjugated conductive polymer preferably does not have a nitrogen atom. Among them, a thiophene-based polymer containing thiophene or its derivative as a structural unit is excellent in terms of transparency. are preferred, and polyalkylenedioxythiophenes are particularly preferred. Polyalkylenedioxythiophenes include polyethylenedioxythiophene, polypropylenedioxythiophene, poly(ethylene/propylene)dioxythiophene, and the like.

In order to further improve the antistatic properties of the thiophene-based polymer containing thiophene or a derivative thereof as a structural unit, a doping agent is added, for example, to 100 parts by mass of the polymer containing thiophene or a derivative thereof as a structural unit. 0.1 parts by mass or more and 500 parts by mass or less can be blended. If the amount is too large, the electron transfer becomes difficult, resulting in a problem of deterioration in antistatic performance. Examples of the doping agent include LiCl, R _1-30 COOLi (R _1-30 : a saturated hydrocarbon group having 1 to 30 carbon atoms), R _1-30 SO ₃ Li, R _1-30 COONa, R _1-30 _SO3Na _, _R1-30COOK _, _R1-30SO3K , Tetraethylammonium, _I2 , _BF3Na _, _BF4Na , HClO4, _CF3SO3H , FeCl3 _, Tetracyanoquinoline (TCNQ) , Na ₂ B ₁₀ Cl ₁₀ , phthalocyanine, porphyrin, glutamic acid, alkyl sulfonate, polystyrene sulfonate Na (K, Li) salt, styrene/styrene sulfonate Na (K, Li) salt copolymer, polystyrene sulfonate anion , styrenesulfonic acid/styrenesulfonic acid anion copolymer, and the like.

In the present invention, the conductive polymer contained in the antistatic layer is preferably contained in an amount of 5% by mass or more, more preferably 10% by mass or more, based on 100% by mass of the total solid content in the antistatic layer. In the case of using a π-electron conjugated conductive polymer as an antistatic agent, when using the doping agent, the content of the π-electron conjugated conductive polymer in the antistatic layer specified in the present application is It is the total amount of the conductive polymer and the doping agent.
By including the antistatic agent in such an amount, good antistatic properties can be imparted.

In the present invention, the conductive polymer contained in the antistatic layer is preferably 50% by mass or less, more preferably 30% by mass or less, based on 100% by mass of the total solid content in the antistatic layer. In the case of using a π-electron conjugated conductive polymer as an antistatic agent, when using the doping agent, the content of the π-electron conjugated conductive polymer in the antistatic layer specified in the present application is It is the total amount of the conductive polymer and the doping agent.
By containing the antistatic agent in such an amount, it does not interact with the binder resin (B) and the like, the coating liquid is less likely to aggregate, and the antistatic layer has few defects and can maintain high transparency.

[Binder resin (B)]
The antistatic layer of the present invention contains a binder resin (B). The binder resin is not particularly limited, but specific examples include polyester resin, acrylic resin, urethane resin, polyolefin resin, polyvinyl resin (polyvinyl alcohol, etc.), polyalkylene glycol, polyalkyleneimine, methylcellulose, hydroxycellulose, starch. and the like. Among these resins, polyester resins, acrylic resins, and urethane resins are preferably used from the viewpoint of adhesion to the polyester film. It is more preferable to use an acrylic resin because of the ease of molecular design and molecular weight design.

The binder resin (B) preferably contains a component that lowers the adhesion energy of the antistatic layer surface in order to improve the separation property between the antistatic layer surface and the lamination roll. It is preferable to have a silicone component, a long-chain alkyl component, a fluorine component, etc. as this component. A long-chain alkyl component is more preferable in consideration of transfer to an adherend, and the binder resin (B) is a long-chain alkyl-containing compound. Preferably, binder resin (B) is a long-chain alkyl-containing compound having at least one reactive group, as described below.

By including a long-chain alkyl-containing compound, for example, when the laminated polyester film of the present invention uses a laminating roll when laminating the protective film, the surface opposite to the adhesive layer laminated surface of the protective film and the laminating roll It is possible to suppress the action from becoming strong, and to avoid the deterioration of the separation property of the bonding roll from the protective film. Furthermore, it is possible to uniformly bond the protective film.
Especially in recent years, there are cases where the adhesiveness of the adhesive is lowered so that the deformation of the precision member that is fragile and easily scratched can be suppressed so that the member can be peeled off. It is possible to maintain good separation between the mating roll and the protective film.

The binder resin (B) preferably has at least one reactive group. Although not particularly limited, the binder resin (B) preferably has a hydroxyl group, a carboxyl group, an amino group, an acrylate group, an epoxy group, or the like, and more preferably has a hydroxyl group or a carboxyl group.

As the binder resin (B) of the present invention, an acrylic resin is preferred. In particular, acrylic resins containing long-chain alkyls and having at least one reactive functional group are preferred.

The acrylic resin is preferably an acrylic resin having a hydroxyl group and a carboxyl group in the molecule. It is more preferable that the structural unit having a hydroxyl group is contained in an amount of 15 to 90 mol % in 100 mol % of all structural units. It is preferable that the structural unit having a hydroxyl group is 20 mol % or more because the water solubility of the acrylic resin can be appropriately maintained. On the other hand, when it is 90 mol % or less, it is preferable because the ratio of the low adhesion energy component can be appropriately maintained.

In order to introduce a hydroxyl group into an acrylic resin, a monomer having a hydroxyl group such as 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, or 2-hydroxyethyl ( A ring-opening adduct of γ-butyrolactone or ε-caprolactone to meth)acrylate may be used as a copolymerization component. Among them, 2-hydroxyethyl (meth)acrylate is preferable because it does not inhibit water solubility. In addition, you may use together 2 or more types of these.

The hydroxyl value of the binder resin (B), for example, the hydroxyl value of the acrylic resin is preferably 20 mgKOH/g or more, more preferably 40 mgKOH/g or more, still more preferably 70 mgKOH/g or more, for example 120 mgKOH/g. That's it. If the hydroxyl value of the binder resin (B), for example, the hydroxyl value of the acrylic resin is 20 mgKOH/g or more, the water solubility of the acrylic resin will be good, which is preferable. Regarding this hydroxyl value, an acrylic resin is exemplified, but the resin that can be used for the binder resin (B) of the present invention described above also has a hydroxyl value within the above range, so that the It can be effective.

The hydroxyl value of the binder resin (B), for example, the hydroxyl value of the acrylic resin is preferably 300 mgKOH/g or less, more preferably 250 mgKOH/g or less, still more preferably 200 mgKOH/g or less. If the hydroxyl value of the binder resin (B), for example, the hydroxyl value of the acrylic resin is 300 mgKOH/g or less, the hydroxyl group of the acrylic resin and the antistatic component such as polythiophene do not cause extreme interaction, and the coating liquid is less likely to aggregate. preferable.

The acrylic resin used in the present invention is preferably a resin having a carboxyl group. By having a carboxyl group, it becomes possible to form a crosslinked structure with a crosslinking agent and to easily impart water solubility. Examples include monomers containing a carboxy group such as (meth)acrylic acid, crotonic acid, itaconic acid, maleic acid and fumaric acid, and monomers containing an acid anhydride group such as maleic anhydride and itaconic anhydride.
For example, the binder resin (B) may have a carboxyl group alone, or may have a carboxyl group together with the hydroxyl group.

The monomer having a carboxyl group is preferably 2 mol % or more, more preferably 5 mol % or more, in 100 mol % of all structural units of the acrylic resin. When it is 4 mol % or more, it becomes easy to form a crosslinked structure in the antistatic layer and to impart water solubility, which is preferable. The monomer having a carboxyl group is preferably 65 mol % or less, more preferably 50 mol % or less. When it is 65 mol % or less, the Tg of the resulting coating film does not become too high relative to the preferable range described later, and the film-forming property is favorable, which is preferable.

In order to develop good water solubility, it is preferable to neutralize the carboxyl groups introduced into the acrylic resin by copolymerization of acrylic acid or methacrylic acid. Basic neutralizers include amine compounds such as ammonia, trimethylamine, triethylamine and dimethylaminoethanol, and inorganic basic substances such as potassium hydroxide and sodium hydroxide. It is preferable to use an amine compound as a neutralizing agent for ease of application and ease of formation of a crosslinked structure. The neutralization rate is preferably 30 mol % to 95 mol %, more preferably 40 mol % to 90 mol %. When the neutralization rate is 30 mol% or more, the acrylic resin has sufficient water solubility, the acrylic resin can be easily dissolved during preparation of the coating solution, and there is no risk of whitening of the coated film surface after drying. preferable. On the other hand, when the neutralization rate is 95 mol % or less, the water solubility is not too high, and alcohol or the like can be easily mixed in preparation of the coating liquid, which is preferable.

The acid value of the binder resin (B), for example, the acid value of the acrylic resin is preferably 40 mgKOH/g or more, more preferably 50 mgKOH/g or more, still more preferably 60 mgKOH/g or more. When the acid value of the acrylic resin is 40 mgKOH/g or more, the number of cross-linking points with the cross-linking agent is increased, so that a strong coating film having a higher cross-linking density can be obtained, which is preferable.
As for the acid value, an acrylic resin is exemplified, but the resin that can be used for the binder resin (B) of the present invention described above also has an acid value within the above range, so that the effect of the present specification can be obtained. can play.

The acid value of the binder resin (B), for example, the acid value of the acrylic resin is preferably 400 mgKOH/g or less, more preferably 350 mgKOH/g or less, still more preferably 300 mgKOH/g or less. If the acid value of the acrylic resin is 400 mgKOH/g or less, the carboxyl group of the acrylic resin and the antistatic agent such as polythiophene do not cause excessive interaction, which is preferable because condensation hardly occurs. If aggregation occurs in the coating liquid, the homogeneity of the antistatic layer is deteriorated, and the antistatic property and transparency are degraded.

The long-chain alkyl group in the binder resin (B) preferably has an alkyl group with 8 to 25 carbon atoms in the side chain of the resin.
In one aspect, the acrylic resin into which a long-chain alkyl group is introduced preferably has an alkyl group having 8 to 25 carbon atoms in the side chain of the acrylic resin, more preferably an alkyl group having 12 to 22 carbon atoms, and still more preferably. It is an alkyl group of 16-20. Further, a copolymer having a (meth)acrylic acid ester as a main repeating unit and containing a long-chain alkyl group having 8 to 20 carbon atoms in the transesterified portion can also be preferably used. Examples include lauryl (meth)acrylate, stearyl (meth)acrylate, and the like. Among them, stearyl methacrylate is preferably used in terms of availability, cost, and low adhesion energy.

The monomer having a long-chain alkyl group in the monomers to be copolymerized is preferably 50 mol% or less, more preferably 40 mol% or less, in 100 mol% of all structural units of the binder resin (B), for example, an acrylic resin. When it is 50 mol% or less, the adhesion energy of the antistatic layer on the coating surface is efficiently reduced, and the Tg of the resulting coating does not become too low relative to the preferred range, and the hardness of the coating is maintained high. It is preferable because it can be done. In the present invention, the monomer having a long-chain alkyl group preferably accounts for 5% or more in 100 mol% of all structural units of the acrylic resin. When it is 5% or more, the adhesion energy of the coating surface of the antistatic layer can be reduced, which is preferable.

The glass transition temperature (Tg) of the binder resin (B), for example, an acrylic resin is preferably 50°C or higher, more preferably 55°C or higher, and even more preferably 60°C or higher. It is preferable that the glass transition temperature of the acrylic resin is 50° C. or higher, since the change over time of the antistatic layer is suppressed.

The glass transition temperature (Tg) of the binder resin (B), for example, an acrylic resin is preferably 110°C or lower, more preferably 105°C or lower, and even more preferably 100°C or lower. When the glass transition temperature of the acrylic resin is 110° C. or lower, the coating film becomes too brittle and the antistatic layer is less likely to crack, which is preferable.

A (meth)acrylic monomer or a non-acrylic vinyl monomer can be used as the Tg adjusting monomer that is copolymerized to adjust the Tg to the above range. Specific examples of (meth) acrylic monomers include methyl (meth) acrylate, ethyl (meth) acrylate, isopropyl (meth) acrylate, n-butyl (meth) acrylate, isobutyl (meth) acrylate, n-amyl (meth) acrylates, n-hexyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, n-octyl (meth)acrylate, decyl (meth)acrylate, dodecyl (meth)acrylate, cyclohexyl (meth)acrylate, isobornyl (meth)acrylate, (meth)acrylic acid alkyl esters such as stearyl (meth)acrylate; nitrogen-containing acrylic monomers such as (meth)acrylamide, diacetoneacrylamide, n-methylolacrylamide, and (meth)acrylonitrile; and vinyl methacrylate. These can be used alone or in combination of two or more.

Examples of non-acrylic vinyl monomers include styrene, α-methylstyrene, vinyltoluene (a mixture of m-methylstyrene and p-methylstyrene), styrene-based monomers such as chlorostyrene; vinyl acetate, vinyl propionate, and vinyl butyrate. , vinyl caproate, vinyl caprylate, vinyl caprate, vinyl laurate, vinyl myristate, vinyl palmitate, vinyl stearate, vinyl cyclohexanecarboxylate, vinyl pivalate, vinyl octylate, vinyl monochloroacetate, divinyl adipate, Vinyl esters such as vinyl crotonate, vinyl sorbate, vinyl benzoate and vinyl cinnamate; vinyl halide monomers such as vinyl chloride and vinylidene chloride;

The monomers for adjusting Tg are preferably the balance after determining the appropriate amounts of the hydroxyl group-containing monomer and the carboxyl group-containing monomer. The Tg of the copolymer is determined by the following Fox formula.

W _n : mass fraction of each monomer (% by mass)
Tg _n : Tg (K) of homopolymer of each monomer

The acrylic resin used in the present invention can be obtained by known radical polymerization. Emulsion polymerization, suspension polymerization, solution polymerization, bulk polymerization, and the like can all be adopted. From the point of handleability, solution polymerization is preferred. Water-soluble organic solvents that can be used for solution polymerization include ethylene glycol n-butyl ether, isopropanol, ethanol, n-methylpyrrolidone, tetrahydrofuran, 1,4-dioxane, 1,3-oxolane, methyl solosolve, and ethyl solosolve. , ethyl carbitol, butyl carbitol, propylene glycol monopropyl ether, propylene glycol monobutyl ether and the like. These may be used by mixing with water.

The polymerization initiator may be any known compound that generates radicals, but water-soluble azo polymerization initiators such as 2,2-azobis-2-methyl-N-2-hydroxyethylpropionamide are preferred. The temperature, time, etc. of the polymerization are appropriately selected.

The weight average molecular weight (Mw) of the binder resin (B) is preferably about 10,000 to 200,000. A more preferred range is from 20,000 to 150,000. When Mw is 10,000 or more, the toughness of the coating film is improved and the strength of the coating film is increased, which is preferable. When the Mw is 200,000 or less, the viscosity of the coating liquid does not significantly increase and the coatability is good, which is preferable.

The antistatic layer of the present invention preferably contains 10% by mass or more, more preferably 40% by mass or more, of the binder resin (B) based on 100% by mass of the total solid content in the antistatic layer. A content of 10% by mass or more is preferable because the static water contact angle increases.

The antistatic layer of the present invention preferably contains the binder resin (B) in an amount of 70% by mass or less, more preferably 60% by mass or less, based on 100% by mass of the total solid content in the antistatic layer. If the binder resin (B) is 70% by mass or less, it is preferable because it does not cause interaction with an antistatic agent such as polythiophene and is less likely to condense. In addition, it is possible to suppress the occurrence of aggregation in the antistatic layer-forming composition that forms the antistatic layer, and it is possible to avoid deterioration of the uniformity of the antistatic layer. can bring about improvement.

(Crosslinking agent (A))
In the present invention, the antistatic layer is formed from a composition containing a cross-linking agent (A) in order to form a crosslinked structure in the antistatic layer. Containing the cross-linking agent (A) is preferable because the durability is improved and deterioration of the antistatic performance is suppressed even when treated under high temperature and high humidity conditions. Specific cross-linking agents include urea-based, epoxy-based, melamine-based, isocyanate-based, oxazoline-based, carbodiimide-based, and aziridine-based agents. In one embodiment, the cross-linking agent (A) comprises at least one selected from acrylamides, melamine resins, carbodiimides, oxazolines, isocyanates and aziridines. The cross-linking agent (A) is particularly preferably melamine-based, oxazoline-based, carbodiimide-based, or aziridine-based. In addition, a catalyst or the like can be appropriately used as necessary in order to accelerate the cross-linking reaction.

The cross-linking agent (A) contained in the antistatic layer of the present invention is preferably contained in an amount of 15% by mass or more, more preferably 20% by mass or more, and still more preferably 100% by mass of the total solid content in the antistatic layer. is 25% by mass. If it is 15% by mass or more, the number of cross-linking points with the binder increases, so that a strong coating film with a higher cross-linking density can be obtained, and heat resistance and alcohol resistance are good, which is preferable.

The cross-linking agent (A) is preferably contained in an amount of 75% by mass or less, for example 65% by mass or less, and may be 55% by mass or less, based on 100% by mass of the total solid content in the antistatic layer. When it is 75% by mass or less, heat resistance and alcohol resistance can be maintained while maintaining the static contact angle within the target range.

A surfactant may be used in the antistatic layer in the present invention to improve the appearance. Examples of surfactants include nonionic surfactants such as polyoxyethylene octylphenyl ether, polyoxyethylene alkyl ether, polyoxyethylene sorbitan fatty acid ester, and fluoroalkylcarboxylic acids, perfluoroalkylcarboxylic acids, perfluoroalkylbenzenesulfones. Acids, fluorine-based surfactants such as perfluoroalkyl quaternary ammonium and perfluoroalkylpolyoxyethylene ethanol, and silicone-based surfactants can be used.

In addition to the above, the antistatic layer may contain lubricants, pigments, ultraviolet absorbers, silane coupling agents, etc., if necessary, as long as the objects of the present invention are not hindered.

In one aspect, the laminated polyester film is substantially free of silicone compounds. Preferably, the antistatic layer is substantially free of silicone compounds.
In the present invention, "substantially free of silicone compounds" is defined as being 50 ppm or less, preferably 10 ppm or less, most preferably detection limit or less when Si element is quantified by fluorescence X-ray analysis. content. “Even if silicone components are not actively added to the film, contaminants derived from foreign substances and dirt adhering to the raw material resin or the lines and equipment in the film manufacturing process will peel off and enter the film. This is because there are cases where
Since the laminated polyester film contains substantially no silicone compound, even when this antistatic film is used as a protective film, it is possible to avoid the transfer of silicone to the protected product, and there is no adverse effect on the final product. can be reduced.

The film thickness of the antistatic layer of the present invention is preferably 0.005 µm or more and 1 µm or less. It is more preferably 0.01 μm or more and 0.5 μm or less, and still more preferably 0.01 μm or more and 0.2 μm or less. When the film thickness of the antistatic layer is 0.005 μm or more, an antistatic effect can be obtained, which is preferable. On the other hand, when the thickness is 1 μm or less, coloring is less and transparency is improved, which is preferable.　

The surface resistivity of the antistatic layer of the present invention is 9 [logΩ/□] or less. More preferably, it is 8 [logΩ/□] or less, and still more preferably 7 [logΩ/□] or less. By setting the surface resistivity to 9 [logΩ/square] or less, it is possible to suppress the charging of the protective film and prevent the adhesion of foreign matter during the process. Electrical adverse effects can be suppressed.

Although the lower limit of the surface resistivity of the antistatic film does not have to be specified, it is preferably 3 [logΩ/□] or more. If the surface resistivity of the antistatic film is less than 3 [logΩ/□], the processing cost of the antistatic layer increases, which is not preferable.

The adhesion energy of water on the surface of the antistatic layer of the antistatic film of the present invention is 3.5 mJ/m ² or less. More preferably, it is 3.2 mJ/m ² or less, for example, 2.9 mJ/m ² or less.
If the adhesion energy of water is 3.5 mJ/m ² or less, it is preferable because when the protective film is used as a protective film and the protective film is used as a protective film, the protective film can be separated from the protective film when the film is laminated to an adherend with the protective film. . The adhesion energy of water of 3.5 mJ/m ² or less can be achieved by adding an appropriate amount of a low surface free energy component to the antistatic layer. By adopting a polymer containing, it is possible to reduce the adhesion energy and provide a protective film that does not transfer to the adherend, which is preferable.
For example, in the present invention, the polymer containing a low surface free energy component may be a conductive polymer or the binder resin (B), both of which are polymers containing a low surface free energy component. may be

The adhesion energy of water on the surface of the antistatic layer of the antistatic film of the present invention is preferably 1.1 mJ/m ² or more, more preferably 1.3 mJ/m ² or more. When the adhesion energy of water is within such a range, wettability is good and defects such as repelling are less likely to occur even when an adhesive layer or the like is processed on the antistatic layer.

The static contact angle of water on the surface of the antistatic layer of the antistatic film of the present invention is 70° or more and 95° or less, for example, 75° or more and 95° or less, and 80° or more and 95° or less. may
When the static contact angle of water is within such a range, it is possible to suppress an increase in the interaction between the surface of the protective film opposite to the surface on which the adhesive layer is laminated and the bonding roll.

In the present invention, it is important to set the static contact angle and adhesion energy of water within the above ranges.
For example, even if the adhesion energy of water is 3.5 mJ/m ² or less, if a film having a static contact angle of water of 95° or more is used, the lamination roll separation property is good, but charging When the adhesive layer is processed onto the protective layer, the coatability tends to deteriorate, resulting in a protective film with many defects. Especially when the static contact angle of water greatly exceeds 95°, this tendency becomes stronger.

Here, the laminated polyester film of the present invention is
(1) Surface resistivity: 3 [logΩ/□] or more and 9 [logΩ/□] or less (2) Static contact angle of water: 70° or more and 95° or less (3) Adhesion energy of water: 3.5 mJ/ It is characterized by being m ² or less. By providing all of these (1) to (3), even when the present antistatic film is laminated with an adhesive layer and used as a protective film, it is easy to separate from the laminating roll when laminating the protective film. , it is possible to provide a protective film that suppresses separation electrification and adhesion of foreign matter at the time of separation.
By using the antistatic film that satisfies the range of the static contact angle and adhesion energy of water as a protective film, the workability of the adhesive layer to the antistatic layer is good (for example, the wettability is good, and the drawback is It is possible to provide a protective film that suppresses electrification of the protective film, has good separation from the laminating roll, and is excellent in lamination.

The haze of the laminated polyester film of the present invention is preferably 3.0% or less. It is more preferably 2.5% or less, still more preferably 2.0% or less, for example, 1.5% or less. It is more preferable if it is 1.0% or less. If it is 3.0% or less, it is preferable because the appearance inspection can be performed in a state where the protective film is adhered to the adherend, and it is particularly preferable when the adherend is a member for optical use. The haze may be 0, and may be 0.1% or more, for example.

The haze of the laminated polyester film of the present invention after heating at 140°C for 10 minutes is preferably 1.5 times or less the haze before heating. It is more preferably 1.3 times or less, still more preferably 1.2 times or less. If it is 1.5 times or less, it is preferable because the appearance inspection can be performed in a state where the protective film is adhered to the adherend, and it is particularly preferable when the adherend is a member for optical use.

The total light transmittance of the laminated polyester film (antistatic film) used in the present invention is preferably 80% or more. It is more preferably 85% or more, still more preferably 88% or more. 90% or more is highly preferred. If it is 80% or more, it is preferable because the appearance inspection can be performed in a state where the protective film is attached to the adherend, and it is particularly preferable when the adherend is a member for optical use.

The antistatic layer preferably has a change in surface resistivity after a wiping test with alcohol that is 1.3 times or less the surface resistivity before the test. It is more preferably 1.2 times or less, still more preferably 1.1 times or less. If it is 1.3 times or less, it is preferable because the initial surface resistivity is maintained when the protective film is formed even if alcohol is used in the process of adhesion processing.

The area average surface roughness (Sa) of the surface of the antistatic layer is preferably in the range of 1 to 40 nm, more preferably 1 to 30 nm. More preferably, it is 1 to 10 nm. The maximum projection height (P) on the surface of the antistatic film used in the present invention is preferably 2 μm or less, more preferably 1.5 μm or less. More preferably, it is 0.8 μm or less. If Sa is 40 nm or less and P is 2 μm or less, it is preferable because there is no risk of roughening the adhesive surface when the adhesive layer is laminated and wound into a roll.

As a method for coating and laminating an antistatic layer on the substrate film surface, a coating liquid in which the above-mentioned antistatic agent or binder resin is dispersed or dissolved in a solvent is applied by a gravure roll coating method, a reverse roll coating method, a knife coater method, There are coating methods such as dip coating, bar coating, and spin coating, but the coating method suitable for the conductive composition is not particularly limited. Moreover, it can be provided by an in-line coating method in which a coating layer is provided in the film production process, or an off-line coating method in which a coating layer is provided after film production.

The drying temperature for forming the antistatic layer by the above method is usually 60°C or higher and 150°C or lower, preferably 90°C or higher and 140°C or lower. When this temperature is 60° C. or higher, the treatment can be performed in a short period of time, which is preferable from the viewpoint of improving productivity. Moreover, since a crosslinking reaction progresses sufficiently when a crosslinking agent is included, it is preferable. On the other hand, when this temperature is 150° C. or lower, the flatness of the film is maintained, which is preferable.

An adhesive layer can be laminated on the laminated polyester film of the present invention by applying and curing an adhesive. The adhesive is not particularly limited and can be used, and the laminated film obtained is used as a protective film. Either side of the antistatic film may be the surface on which the adhesive layer is laminated. When using an antistatic film having an antistatic layer only on one side, it is preferable that the antistatic layer is provided on the side opposite to the side on which the adhesive layer is laminated.
Moreover, a ceramic green sheet, a resin film, or the like may be laminated on the antistatic layer in the laminated polyester film of the present invention.

In order to describe the present invention in detail, examples will be given below, but of course the present invention is not limited to these examples. The evaluation methods used in the present invention are as follows.

(NMR measurement)
The ratio of the copolymer components introduced into the long-chain alkyl-containing compound having at least one reactive group was determined using nuclear magnetic resonance spectroscopy (1H-NMR, 13C-NMR: Varian Unity 400, manufactured by Agilent). confirmed. The measurement was carried out by removing the solvent in the synthesized acrylic resin with a vacuum dryer, and then dissolving the dried product in heavy chloroform. From the obtained NMR spectrum, peaks with chemical shifts δ (ppm) assigned to the sites of each group were identified. The integrated intensity of each peak obtained was determined, and the composition ratio (mol%) of the copolymer component introduced into the acrylic resin was confirmed from the number of hydrogen atoms at the site of each group and the integrated intensity.

(Confirmation of Tg)
The Tg of each long-chain alkyl-containing compound was determined from the composition ratio of the copolymer components determined by the NMR measurement and the above-described Fox equation.

(Surface resistivity)
The surface resistivity of the surface of the antistatic film of the present invention was determined by measuring the surface resistivity of the antistatic layer surface after adjusting the humidity for 24 hours under conditions of a temperature of 23° C. and a humidity of 55% using a surface resistance measuring instrument (manufactured by Simco Japan Co., Ltd.). , Work Surface Tester ST-3), and evaluated according to the following criteria.
◎: Surface resistivity is 3 or more and 6 or less [logΩ/□]
○: Surface resistivity is more than 6 and 9 or less [logΩ/□]
△: Surface resistivity is over 9 and 12 or less [logΩ/□]
×: Surface resistivity is over 12 [logΩ/□] or more

(Static contact angle of water)
Water (drop volume 1.8 μL) on the antistatic layer surface of the antistatic film using a contact angle meter (manufactured by Kyowa Interface Science Co., Ltd.: fully automatic contact angle meter DM-701) at 25 ° C. and 50% RH. was dropped and the contact angle was measured after 30 seconds. Five points were measured and the average value was adopted.

(Adhesion energy of water)
Water (drop volume 15 μL) is dropped on the antistatic layer surface of the antistatic film using a contact angle meter (manufactured by Kyowa Interface Science Co., Ltd.: fully automatic contact angle meter DM-701) under the conditions of 25 ° C. and 50% RH. Two seconds after dropping, the stage was continuously tilted and the contact angle was measured every 1°. Also, the tilt angle when the droplet moved 5 dots from the position of the droplet at 0° was determined as the sliding angle, and the adhesion energy was calculated therefrom. This calculation was performed using analysis software in this contact angle measurement software (FAMES). Five points were measured and the average value was adopted.

(total light transmittance, haze)
The total light transmittance and haze of the film of the present invention were measured in accordance with JIS K 7136 using a turbidity meter (NDH7000II, manufactured by Nippon Denshoku Co., Ltd.) before and after heat treatment at 140°C for 10 minutes.

(Glass-transition temperature)
Compliant with JIS K7121, using a differential scanning calorimeter (manufactured by Seiko Instruments, DSC6200), 10 mg of resin sample was heated at 20 ° C./min over a temperature range of 25 to 350 ° C., and the compensation obtained from the DSC curve was obtained. The outer glass transition start temperature was taken as the glass transition temperature.

(Alcohol resistance)
A Kimwipe soaked with ethanol was used to measure the surface resistivity before and after the film of the present invention was wiped back and forth 10 times. In addition, changes in appearance after the above treatment were evaluated according to the following criteria.
◎: Almost no change 〇: Slight change △: Change ×: Change to the extent that the antistatic layer permeates

(Production of long-chain alkyl-containing compound b-1 having at least one reactive group)
231 parts by mass of methyl methacrylate (MMA), 130 parts by mass of stearyl methacrylate (SMA), and 100 parts by mass of hydroxyethyl methacrylate (HEMA) were added to a four-necked flask equipped with a stirrer, a reflux condenser, a thermometer and a nitrogen blowing tube. , 33 parts by mass of methacrylic acid (MAA) and 1153 parts by mass of isopropyl alcohol (IPA) were charged, and the temperature in the flask was raised to 80° C. while stirring. Stirring was performed for 3 hours while maintaining the inside of the flask at 80° C., and then 0.5 parts by mass of 2,2-azobis-2-methyl-N-2-hydroxyethylpropionamide was added to the flask. After purging with nitrogen while raising the temperature in the flask to 120° C., the mixture was stirred at 120° C. for 2 hours.
Subsequently, a pressure reduction operation of 1.5 kPa was performed at 120° C. to remove unreacted raw materials and solvent to obtain a long-chain alkyl group-containing acrylic resin. The inside of the flask was returned to atmospheric pressure and cooled to room temperature, and 1592 parts by mass of an IPA aqueous solution (water content: 50% by mass) was added and mixed. Then, using a dropping funnel while stirring, ammonia is added to neutralize the long-chain alkyl group-containing acrylic resin until the pH of the solution is in the range of 5.5 to 7.5, and the solid content concentration is 20. % by mass of long-chain alkyl group-containing acrylic resin (b-1) was obtained. Table 1 also shows the composition ratio, Tg, and acid value of the long-chain alkyl-containing compound (b-1) having at least one reactive group, determined by NMR measurement.

(Example 1)
An antistatic layer coating solution was obtained with the blending amounts shown in Table 2.
(Antistatic layer coating solution)
Water 32.96 parts by mass Isopropyl alcohol 49.45 parts by mass Conductive polymer 8.33 parts by mass Crosslinking agent a-1_1 (manufactured by Nippon Carbide Co., Ltd., melamine resin, imino-methylol type, solid content concentration 70% by mass)
0.86 parts by mass of long-chain alkyl-containing compound b-1 having at least one reactive group (solid concentration: 20% by mass)
6.5 parts by mass Conductive agent 1.8 parts by mass Surfactant (manufactured by Nissin Chemical Co., Ltd., Dynol 604, solid content concentration 100% by mass)
0. part by mass

(Formation of antistatic layer)
The obtained antistatic layer coating solution was coated on one side of A4360 (Cosmoshine (registered trademark), manufactured by Toyobo Co., Ltd.) having a thickness of 75 μm using a gravure coater so that the wet film thickness was 4.5 μm. It was dried and cured in a hot air drying oven at 140° C. for 30 seconds to obtain a polyester film with an antistatic layer.

(Examples 2, 14, 15)
An antistatic layer was formed in the same procedure as in Example 1, except that the composition was changed to that shown in Table 2.

(Example 3)
An antistatic layer was formed in the same manner as in Example 1, except that the composition shown in Table 2 was changed to the cross-linking agent a-2 (Baxenden, blocked isocyanate, solid content concentration: 40% by mass).

(Examples 4 and 13)
An antistatic layer was formed in the same manner as in Example 1, except that the cross-linking agent a-3_1 (manufactured by Nisshinbo Chemical Co., Ltd., carbodiimide, solid content concentration 40% by mass) was used with the composition shown in Table 2.

(Example 5)
An antistatic layer was formed in the same manner as in Example 1, except that the composition shown in Table 2 was used as a cross-linking agent a-3_2 (carbodiimide manufactured by Nisshinbo Chemical Co., Ltd., solid content concentration 41% by mass).

(Examples 6-7)
An antistatic layer was formed in the same manner as in Example 1, except that the cross-linking agent a-1_2 (manufactured by Nippon Carbide Co., Ltd., melamine resin, imino type, solid content concentration 80% by mass) was used with the composition shown in Table 2. .

(Example 8)
An antistatic layer was formed in the same manner as in Example 1 except that the cross-linking agent a-1_3 (manufactured by Nippon Carbide Co., Ltd., melamine resin, imino type, solid content concentration 70% by mass) was used with the composition shown in Table 2. .

(Example 9)
An antistatic layer was formed in the same manner as in Example 1 except that the cross-linking agent a-1_4 (manufactured by Nippon Carbide Co., Ltd., melamine resin, imino-methylol type, solid content concentration 70% by mass) was used with the composition shown in Table 2. formed.

(Example 10)
An antistatic layer was formed in the same manner as in Example 1 except that the cross-linking agent a-1_5 (manufactured by Nippon Carbide Co., Ltd., melamine resin, imino-methylol type, solid content concentration 70% by mass) was used with the composition shown in Table 2. formed.

(Example 11)
An antistatic layer was formed in the same manner as in Example 1, except that the cross-linking agent a-1_6 (manufactured by Nippon Carbide Co., Ltd., melamine resin, full ether type, solid content concentration 70% by mass) was used with the composition shown in Table 2. bottom.

(Example 12)
An antistatic layer was formed in the same procedure as in Example 1, except that the cross-linking agent a-1_7 (manufactured by Nippon Carbide Co., Ltd., melamine resin, methylol type, solid content concentration 70% by mass) was used with the composition shown in Table 2. .

(Example 16)
The same as in Example 1 except that the long-chain alkyl-containing compound b-2 (solid content concentration: 20% by mass) having a composition as shown in Table 2 and having a different amount of stearyl methacrylate from the cross-linking agents a-1_1 and b-1 was used. An antistatic layer was formed by the procedure of.

(Example 17)
The same procedure as in Example 1 except that the long-chain alkyl-containing compound b-3 (solid content concentration 20% by mass) having a composition as shown in Table 2 and having a hydroxyl value different from that of the cross-linking agents a-1_1 and b-1 was used. to form an antistatic layer.

(Example 18)
The same procedure as in Example 1 except that the long-chain alkyl-containing compound b-4 (solid content concentration 20% by mass) having a composition as shown in Table 2 and having a hydroxyl value different from that of the cross-linking agents a-1_1 and b-1 was used. to form an antistatic layer.

(Comparative example 1)
Except for using a cross-linking agent a-1_1 and a long-chain alkyl-containing compound b-5 (manufactured by Chukyo Yushi Co., Ltd., Resem T-738, solid content concentration 20% by mass) with the composition shown in Table 2, An antistatic layer was formed in the same procedure as in Example 1.

(Comparative example 2)
Except for using a cross-linking agent a-1_1 and a long-chain alkyl-containing compound b-6 (Lion Specialty Chemicals, Pyroyl 406, solid content 15% by mass) having a composition as shown in Table 2, An antistatic layer was formed in the same procedure as in Example 1.

(Comparative Example 3)
An antistatic layer was formed in the same manner as in Example 1 except that the cross-linking agent a-1_1 was used with the composition shown in Table 2 and no long-chain alkyl-containing acrylic resin was included.

Tables 2A to 3D below show various compositions and measured values.

It should be considered that the embodiments and examples disclosed this time are illustrative in all respects and not restrictive. The scope of the present invention is indicated by the scope of the claims rather than the above-described embodiments, and is intended to include meanings equivalent to the scope of the claims and all modifications within the scope.

The laminated polyester film of the present invention obtained in Examples provides an antistatic film in which an antistatic layer with low adhesion energy is laminated on at least one side of a polyester film, and an adhesive layer is laminated on the antistatic film for protection. Even when it is used as a film, it is possible to provide a protective film that is easy to separate from the laminating roll when laminating the protective film, and that suppresses separation electrification and adhesion of foreign matter during peeling.

On the other hand, Comparative Example 1 does not contain a long-chain alkyl-containing compound having at least one reactive group, which is the binder resin (B). A film with many defects was obtained because the coatability deteriorated when the adhesive layer was processed.
Since Comparative Example 2 does not contain a long-chain alkyl-containing compound having at least one reactive group, which is the binder resin (B), the coating properties deteriorated when the adhesive layer was processed onto the antistatic layer. A film with many defects was obtained.
Comparative Example 3 does not contain a long-chain alkyl-containing compound having at least one reactive group, which is the binder resin (B). A film with many defects was obtained because the coatability deteriorated during processing.

TECHNICAL FIELD The present invention relates to an antistatic film and an adhesive film obtained by laminating an adhesive layer on an antistatic film, and more particularly to a protective film for optical members (for example, constituent members of organic EL and liquid crystal displays).

Claims

A laminated polyester film having an antistatic layer on at least one side of the substrate,
The antistatic layer is a layer obtained by curing a composition containing a conductive polymer, a cross-linking agent (A), and a binder resin (B),
The binder resin (B) is a long-chain alkyl-containing compound having at least one reactive group,
The antistatic layer is a laminated polyester film that satisfies the following (1)-(3):
(1) Surface resistivity: 3 [logΩ/□] or more and 9 [logΩ/□] or less (2) Static contact angle of water: 70° or more and 95° or less (3) Adhesion energy of water: 3.5 mJ/ m2 or less.
The laminated polyester film according to claim 1, wherein the laminated polyester film has a total light transmittance of 80% or more and a haze of 3.0% or less.
The laminated polyester film according to claim 1 or 2, wherein the haze after heating the laminated polyester film at 140°C for 10 minutes is 1.5 times or less the haze before heating.
The laminated polyester film according to any one of claims 1 to 3, wherein the antistatic layer has a surface resistivity change after a wiping test with alcohol that is 1.3 times or less the surface resistivity before the test.
The laminated polyester film according to any one of claims 1 to 4, wherein the conductive polymer is contained in an amount of 5% by mass or more and 50% by mass or less with respect to 100% by mass of the total solid content in the antistatic layer.
The laminated polyester film according to any one of claims 1 to 5, wherein the cross-linking agent (A) and the binder resin (B) are contained in the following ranges with respect to 100% by mass of the total solid content in the antistatic layer.
(A) 15% by mass or more and 75% by mass or less (B) 10% by mass or more and 70% by mass or less
The laminated polyester film according to any one of claims 1 to 6, wherein the binder resin (B) has a hydroxyl value of 20 mgKOH/g or more and 300 mgKOH/g or less.
The laminated polyester film according to any one of claims 1 to 7, wherein the binder resin (B) contains a carboxyl group.
The laminated polyester film according to any one of claims 1 to 8, wherein the cross-linking agent (A) contains at least one selected from acrylamide, melamine resin, carbodiimide, oxazoline, isocyanate and aziridine.
The laminated polyester film according to any one of claims 1 to 9, wherein the laminated polyester film does not substantially contain a silicone compound.
A protective film obtained by laminating an adhesive layer on at least one side of the laminated polyester film according to any one of claims 1 to 11.