JP2623707B2 - Electrostatic recording film - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrostatic recording film, and more particularly, to a static image in which an electric signal is directly converted into an electrostatic latent image and then developed with a toner to form a visible image. It relates to an electronic recording film. More specifically, it relates to an electrostatic recording printer / plotter for CAD (interactive design).

[Prior Art] An electrostatic recording film in which a polyester film, a conductive layer, and a dielectric layer are laminated in this order is known.

In the electrostatic recording method, a recording voltage is applied to a multi-pin electrode head (hereinafter abbreviated as a pin electrode), and air discharge is caused in a minute gap (hereinafter abbreviated as a gap) between the pin electrode and a dielectric layer of the electrostatic recording film. Then, an electrostatic latent image is formed on the surface of the dielectric layer, and then the electrostatic latent image is developed with toner to form a visible image. In order to obtain a stable image in this way, it is necessary to control the gap from the Passien curve to an appropriate range. To this end, the insulating layer is added, and the gap between the pin and the dielectric layer provided with appropriate irregularities is brought into contact. Is most commonly used.

In such an electrostatic recording film, it is effective to provide an antistatic layer on the polyester film surface opposite to the dielectric layer in order to improve printing runnability, adhesion of dust and foreign matter, handling of drawn drawings, and the like. It is used for As a method of providing the antistatic layer, various antistatic agents in the base polyester film, for example, metal powder, tin oxide-antimony conductive agent, a surfactant having an antistatic ability, styrene sulfonic acid or a salt thereof and the like. A method of kneading or blending into a polymer binder and applying it is adopted (for example, Monthly Specialty Chemicals, 1980.
Five).

[Problems to be Solved by the Invention] However, metal powders and tin oxide-antimony based conductive agents have excellent antistatic effects, but are insufficient in transparency and cost. In addition, when an antistatic agent such as a surfactant is kneaded in, or blended in a coating agent and applied, the antistatic agent bleeds out to the surface or interface, and migration occurs over time, and the surface becomes cloudy. It has drawbacks such as reduced transparency and reduced adhesion to the base polyester film, and when the electrostatic recording film is stored in roll form, the antistatic agent is transferred to the dielectric layer surface. It has disadvantages such as adversely affecting image characteristics. There are further disadvantages such as heat treatment at high temperatures and deterioration of antistatic properties over time.

An object of the present invention is to eliminate the above-mentioned disadvantages, namely, antistatic properties, transparency, excellent adhesiveness, and transfer of the antistatic layer to the dielectric layer surface of the electrostatic recording film even when stored in a roll. It is an object of the present invention to provide an electrostatic recording film capable of obtaining a clear image stably without any problem.

[Means for Solving the Problems] The present invention has the following configuration in order to achieve the above object. That is, the antistatic layer (A), the polyester film layer (B), the conductive layer (C) and the dielectric layer (D) are formed as (A)
/ (B) / (C) / (D) or (A) / (B) /
In the electrostatic recording film laminated in the order of (A) / (C) / (D), the above (A) / (B) layer or (A) /
The (B) / (A) layer comprises a polyester film and a polymer binder on one or both sides of the polyester film and a compound represented by the general formula (I): (Where R is hydrogen or a methyl group, X is hydrogen, an alkali metal, an alkaline earth metal or ammonium, R ₁ , R ₂ ,
R ₃ and R ₄ are each hydrogen, halogen, an alkyl group or an alkoxy group. An electrostatic recording characterized by being obtained by applying an antistatic layer mainly composed of a polymer having a repeating unit represented by the following formula as a main component, and then stretching in at least one direction. The gist is a film.

That is, in the present invention, the antistatic layer (A) containing a specific polymer as a main component and the polyester film (B) layer are formed in the electrostatic recording film in the form of (A) / (B) or (A) /
(B) / (A). The antistatic polyester film is characterized by applying an antistatic agent to one or both sides of an unstretched polyester film or a uniaxially stretched polyester film. After that, it can be obtained by biaxially or uniaxially stretching to form a biaxially oriented polyester film.

Hereinafter, the layers (A) and (B) will be described in more detail.

In the present invention, the antistatic layer (A) comprises a layer mainly composed of a polymer having a polymer binder and a repeating unit represented by the general formula (I) as a main component.

General formula (Where R is hydrogen or a methyl group, X is hydrogen, an alkali metal, an alkaline earth metal or ammonium, R ₁ , R ₂ ,
R ₃ and R ₄ are each hydrogen, halogen, an alkyl group having 1 to 5 carbon atoms or an alkoxy group. Representative examples of the general formula (I) include: In the form of acrylic acid, acrylic acid ester, methacrylic acid, methacrylic acid ester, or copolymerized with styrene, or And polymers consisting of only one polymer.

Among them As shown in the above, those obtained by sulfonating polystyrene or polymerizing styrene sulfonic acid are more preferably used, wherein X ⁺ ions are H ⁺ , NH ₄ ⁺ , K ⁺ , Na ⁺ , L ⁺
i ^{+ and the} like. Among them, X ⁺ ion
It is preferable to use sulfonated polystyrene which is H ⁺ or NH ₄ ^{+ from} the viewpoint of antistatic properties. H ⁺ ions are more preferable because the thickness of the coating film can be reduced.

The molecular weight of the sulfonated polystyrene and / or its salt is preferably 10,000 to 1,000,000, more preferably 3 to 1,000,000.
10,000 to 300,000.

The polymer binder is not particularly limited, but is preferably mixed with a water-soluble or water-dispersible resin from the viewpoint of dispersibility.
As the water-soluble or water-dispersible resin, a thermoplastic resin,
A curable resin that is cured by heat or the like can be given.

For example, polyester resins, acrylic resins, polyamide resins, urethane resins, vinyl resins, butadiene resins, epoxy resins, silicone resins, or mixtures and copolymers thereof.

Methylol or alkylol urea, melamine, acrylamide, polyamide, etc. as a crosslinking agent to improve the adhesion (blocking properties), water resistance, solvent resistance and mechanical strength of the antistatic layer (A) A reactive compound such as a resin, an epoxy compound, an aziridine compound, a blocked polyisocyanate, and a vinyl compound may be contained in the antistatic layer (A). The antistatic layer (A) of the present invention may contain, if necessary, an antifoaming agent, a coating improver, a thickener, an organic lubricant, an inorganic fine particle, an antioxidant, an ultraviolet absorber, a foaming agent, and a dye. , A pigment and the like.

In order to improve the coatability and adhesion of the antistatic layer (A) to the film, the film may be subjected to a chemical treatment or a discharge treatment before the application.

As the water-soluble or water-dispersible resin, it is preferable to use polyurethane, polyester, or acrylic resin from the viewpoint of adhesiveness and transparency. Specific examples of preferred polyurethanes include those in which the polyurethane has at least one of a carboxylic acid group, a sulfonic acid group, and a sulfuric acid half ester base, and among them, those in which an ammonium salt is formed.

Specific examples of preferable polyesters include polyesters obtained by copolymerizing 0.5 to 20 mol% of 5-sulfosodiisophthalic acid. Among them, at least one of terephthalic acid, isostaric acid, and adipic acid is used as an acid component, and at least one of ethylene glycol or hexane glycol, 1,4-butanediol, diethylene glycol, neopentyl glycol, and tetramethylene glycol is used as an alcohol component. It is particularly preferable to use a polyester having a viscosity of 3 to 6 cps when diluted at 5% by weight because not only the adhesiveness and antistatic property but also the surface of the antistatic layer (A) is smooth and excellent in film gloss.

Examples of the acrylic resin include those having an alkyl acrylate or an alkyl methacrylate as a main component, and 30 to 99.9 mol% of the component, and a vinyl monomer component 70 to 70 having a functional group copolymerizable therewith. A water-soluble or water-dispersible resin containing 0.1 mol% is preferred.

Vinyl monomers copolymerizable with alkyl acrylate or alkyl methacrylate and having a functional group,
Preferably, the resin has a functional group that imparts hydrophilicity to the resin to improve the water dispersibility of the resin, or a resin and a polyester film, or a functional group that improves the adhesiveness with another coating layer provided on the undercoat layer, Preferred functional groups include a carboxyl group or a salt thereof, an acid anhydride group, a sulfonic acid group, or a salt thereof, an amide group or an alkylolated amide group, an amino group (including a substituted amino group), or an alkylolated group. Amino groups or salts thereof, hydroxyl groups, epoxy groups and the like. Particularly preferred are a carboxyl group or a salt thereof, an acid anhydride group, an epoxy group and the like. Two or more of these groups may be contained in the resin.

The reason why the content of the alkyl acrylate or alkyl methacrylate in the acrylic resin is preferably 30 mol% or more is because the coating formability, the strength of the coating film, and the blocking resistance are improved. It is preferable that the content of the alkyl acrylate or alkyl methacrylate in the acrylic resin is 99.9 mol% or less because the compound having a specific functional group is introduced into the acrylic resin as a copolymer component to make the acrylic resin water-soluble and water-dispersible. This is to make the state easier and to stabilize the state for a long period of time. Further, the adhesion between the antistatic layer (A) and the polyester film (B) layer is improved, and the antistatic layer (A) is formed by a reaction in the coating layer. This is because the strength, water resistance, chemical resistance, and adhesion to other materials can be improved.

Examples of the alkyl group of the alkyl acrylate or alkyl methacrylate include a methyl group, an ethyl group, n
-Propyl group, isopropyl group, n-butyl group, isobutyl group, t-butyl group, 2-ethylhexyl group, lauryl group, stearyl group, cyclohexyl group and the like.

As the vinyl monomer having a functional group copolymerizable with an alkyl acrylate or an alkyl methacrylate, the following compounds having a functional group such as a reactive functional group, a self-crosslinkable functional group, and a hydrophilic group can be used.

Examples of the compound having a carboxyl group or a salt thereof, or an acid anhydride group include acrylic acid, methacrylic acid, itaconic acid, maleic acid, fumaric acid, crotonic acid, metal salts of these carboxylic acids with sodium, ammonium salts, and the like. And maleic anhydride.

As the compound having a sulfonic acid group or a salt thereof,
Examples thereof include vinyl sulfonic acid, styrene sulfonic acid, metal salts of these sulfonic acids with sodium and the like, and ammonium salts.

Examples of the compound having an amide group or an alkylolated amide group include acrylamide, methacrylamide, N-methylmethacrylamide, methylolated acrylamide, methylolated methacrylamide, ureidovinyl ether, β-ureidoisobutylvinylether, ureidoethyl acrylate And the like.

Examples of the compound having an amino group or an alkylolated amino group or a salt thereof include diethylaminoethyl vinyl ether, 2-aminoethyl vinyl ether, 3-aminopropyl vinyl ether, 2-aminobutyl vinyl ether, dimethylaminoethyl methacrylate, and dimethylaminoethyl. Examples thereof include vinyl ethers, those obtained by converting their amino groups to methylol, those obtained by quaternary salification with an alkyl halide, dimethyl sulfate, sultone or the like.

Examples of the compound having a hydroxyl group include β-hydroxyethyl acrylate, β-hydroxyethyl methacrylate, β-hydroxypropyl acrylate, β-hydroxypropyl methacrylate, β-hydroxyvinyl ether, 5-hydroxypentyl vinyl ether,
Examples include hydroxyhexyl vinyl ether, polyethylene glycol monoacrylate, polyethylene glycol monomethacrylate, polypropylene glycol monoacrylate, and polypropylene glycol monomethacrylate.

Examples of the compound having an epoxy group include glycidyl acrylate and glycidyl methacrylate.

Further, in addition to the above, the following compounds may be used in combination. That is, acrylonitrile, methacrylonitrile, styrenes, butyl vinyl ether, mono or dialkyl maleate, mono or dialkyl fumarate, mono or dialkyl itaconate, methyl vinyl ketone, vinyl chloride, vinylidene chloride, vinyl acetate, vinyl pyridine, Examples include, but are not limited to, vinylpyrrolidone and vinyltrimethoxysilane.

The acrylic resin may contain a surfactant, but the low molecular weight surfactant contained in the acrylic resin is condensed during the film formation process and is accumulated at the interface between the particles, or it is prevented from being charged. In some cases, problems such as migration to the interface of the layer (A) occur in the mechanical strength, water resistance, and adhesion to the laminate of the antistatic layer (A). In such a case, a polymer obtained by so-called soap-free polymerization containing no surfactant can be used.

However a copolymer of 35 / 65-65 / 35 (molar ratio) of methyl methacrylate and methyl acrylate among them the backbone polymer, -COOH, are each from 1 to 5 wt% introducing water dispersible acrylic and -CH ₂ OH Particularly preferred.

As described above, the antistatic layer (A) of the present invention contains, as the main components, a polymer binder and a polymer having the repeating unit represented by the general formula (I) as a main component. It is necessary to be.

The amount of the polymer having the repeating unit represented by the general formula (I) as a main component in the antistatic layer (A) is 10% by weight or more.
It is preferably at most 95% by weight. If less than 10% by weight,
It is not preferable because the antistatic property is insufficient, and if it is more than 95% by weight, the toughness of the coating film is poor, which is not preferable.

Although the thickness of the antistatic layer (A) after stretching is not particularly limited, it is usually 0.001 to 5 μm. Preferably 0.01 to 0.4
μm.

In addition, if necessary, inorganic particles may be added to the antistatic layer (A).
μm or less, more preferably 0.5 μm or less, particularly preferably 0.2 μm or less, specifically titanium oxide, alumina, silica, silica sol, zirconium, calcium carbonate, barium salt, molybdenum sulfate, carbon black, Examples include, but are not limited to, kaolin.

The polyester film layer (B) in the present invention is:
It is composed of a polyester having an aromatic dicarboxylic acid as a main component and an alkylene glycol as a main glycol component.

Specific examples of the aromatic dicarboxylic acid include terephthalic acid, isophthalic acid, naphthalenedicarboxylic acid, diphenoxyethane dicarboxylic acid, diphenyl dicarboxylic acid, diphenyl ether dicarboxylic acid, diphenyl sulfone dicarboxylic acid, diphenyl ketone dicarboxylic acid, anthracene dicarboxylic acid, α , Β-bis (2-chlorophenoxy) ethane-4,4'-dicarboxylic acid and the like.
Of these, terephthalic acid is particularly desirable.

Specific examples of the alkylene glycol include ethylene glycol, trimethylene glycol, tetramethylene glycol, pentamethylene glycol, hexamethylene glycol, and hexylene glycol.

Of course, these polyesters may be homopolyesters or copolyesters (copolyesters), and the components to be copolymerized include, for example, diethylene glycol, propylene glycol, neopentyl glycol, polyalkylene glycol, p- Xylylene glycol, 1,4-cyclohexanedimethanol, 5
Diol components such as sodium sulforesorcin, adipic acid, sebacic acid, phthalic acid, isophthalic acid, 2,6
Dicarboxylic acid components such as -naphthalene dicarboxylic acid and 5-sodium sulfoisophthalic acid; polyfunctional dicarboxylic acid components such as trimellitic acid and pyromellitic acid; and oxycarboxylic acid components such as p-oxyethoxybenzoic acid.

The thickness of the polyester film is 10μm ~ 250μ
m is preferable. More preferably, 15 μm to 15
It is desirable that the thickness is 0 μm. If the thickness is smaller than 0 μm, the mechanical strength of the film is insufficient.

Next, one example of a method for producing the antistatic polyester film used in the present invention will be specifically described.

That is, the aforementioned polyester (for example, intrinsic viscosity 0.40
The pellets are fed to an extruder, melted at about 280 ° C., extruded from a die into a sheet, and wound around a cooling drum at 50 to 60 ° C. to be cooled and solidified. After applying the above-mentioned antistatic layer (A) to one or both surfaces of the sheet using a method such as bar coating, the sheet is stretched 2 to 5 times simultaneously in the longitudinal and width directions while drying at 100 to 105 ° C. Then, heat treatment is performed at 200 to 240 ° C. to obtain a polyester film having antistatic properties. Alternatively, after cooling and solidifying into a sheet, the sheet is stretched 2 to 5 times in the longitudinal direction at 90 to 100 ° C., and the above-mentioned antistatic layer (A) is coated on one or both sides of the film by a known method. Then, the polyester film having antistatic properties can be obtained by stretching the film 2 to 5 times in the width direction while drying the film at 100 to 150 ° C, and further heat-treating the film at 200 to 240 ° C.

The antistatic layer (A) may be applied as it is on a sheet or a film. However, it is more preferable to perform a corona discharge treatment in air or other various atmospheres in order to improve applicability and adhesion.

As the conductive layer of the present invention, a commonly known conductive layer is used. The surface electric resistance is preferably 10 ⁴ to 10 ⁹ Ω / port. Examples of such a conductive layer include (1) a layer made of an electron conductive metal or metal oxide, (2) a layer coated with an ion conductive polymer electrolyte, and (3) a conductive powder and a polymer binder. Or a layer coated with a polymer electrolyte.

In this case, a generally known electron conductive metal or metal compound, ion conductive polymer electrolyte, or conductive powder is used. Such preferred compositions include Al, Cr, Cd, Ti,
Metals such as Fe, Cu, In, Ni, Pd, Pt, Rh, Ag, Ru, w, Sn, Zr, Ir,
Alloys such as stainless steel, brass and Ni-Cr, metal oxides such as indium oxide, tin oxide, zinc oxide, titanium oxide, vanadium oxide, ruthenium oxide and tantalum oxide, and metal compounds such as copper iodide. However, the present invention is not limited to these. These may be used alone or in combination of two or more kinds. As the polymer electrolyte, quaternary ammonium salts, sulfonates,
Examples include, but are not limited to, polyalcohols. These may be used alone or in combination of two or more. Such a conductive layer is formed by plating, vacuum deposition, chemical vapor deposition, sputtering, coating, or the like.

The dielectric layer of the present invention comprises particles for forming a gap with the polymer binder. As such a polymer binder, a commonly known polymer binder having a volume resistivity of 10 ¹² Ω · cm or more is used. For example, polyester, polyesteramide, polyvinyl chloride, poly (meth) acrylate, polyamide, polyurethane, polycarbonate, polystyrene, polymethylpentene, alkyd resin, phenol resin, epoxy resin, chlorinated polyolefin, polyvinyl butyral, and the like, and the like. Copolymer mixtures and the like.

As the particles, generally known inorganic particles and organic particles are used. Such particles have a volume resistivity of 10 ⁸ Ωcm
It is more preferably at least 10 ¹⁰ Ω · cm. Examples of such inorganic particles include metal oxides such as silicon oxide, titanium oxide, alumina, lead oxide and zirconium oxide; salts such as calcium carbonate, barium titanate and barium sulfate; and examples of organic particles include styrene-divinylbenzene. It is appropriately selected from a copolymer, a melamine resin, an epoxy resin, a phenol resin, a fluororesin, and the like. These particles may be used alone or in combination of two or more. The average particle size of the above-mentioned particles is preferably appropriately selected generally in the range of 0.1 to 15 μm from the viewpoint of discharge stability.

In the present invention, the weight ratio between the polymer binder forming the dielectric layer and the particles is preferably selected in the range of 100 / 0.5 to 100/150. If the weight ratio is lower than this, the stability of the discharge is poor, and if it is higher than this, the film strength of the dielectric layer is undesirably weak.

The thickness of the dielectric layer is preferably from 1 to 20 μm.
If it is thinner than this, the surface potential is low, and if it is thicker than this, the resolution deteriorates, which is not preferable.

The dielectric layer may be stacked in a plurality of layers in addition to a single layer, or an intermediate layer such as an adhesive may be provided between the conductive layer and the dielectric layer.

The dielectric layer of the present invention, if necessary, within a range that does not impair the properties of the electrostatic recording film of the present invention, a plasticizer, an adhesion promoter, a stabilizer, an antioxidant, an ultraviolet absorber,
A lubricant or the like may be added, a conductive powder or the like may be added to prevent fogging, or a carbon electrode may be added to an end of the dielectric layer.

As a method of adding a dielectric layer, a known method is effectively used. For example, it is appropriately selected from brush coating, dip coating, knife coating, roll coating, spray coating, flow coating, spin coating (spinner, wheyer, etc.), and the like.

[Effects of the Invention] Since the present invention is configured as described above, the antistatic property,
It is possible to obtain an electrostatic recording film which is excellent in transparency and easy adhesion and which can obtain a stable image without transferring to the dielectric layer surface of the electrostatic recording film.

As described above, since the electrostatic recording film of the present invention has excellent properties, it can be used not only for an electrostatic recording film for hard copy, for an electrostatic printer / plotter or a facsimile, but also for repeated use. As an electrostatic recording film for master films, for copying machines,
Useful as a transfer master for facsimile receivers and printers, as a recording medium that holds a transferred electrostatic latent image in an electrostatic latent image transfer type electrophotographic process (TESI method), and as a recording film for displays using an electrostatic recording method It is.

[Method of measuring characteristics]

(1) Antistatic Property The surface electric resistance (Ω / □) at 20 ° C. and 65% RH at an applied voltage of 100 V was measured using a super insulation resistance meter MODEL-VE-40 (manufactured by Kawaguchi Electric Co., Ltd.).

(2) Surface resistance of the conductive layer Cut the conductive film into a width of 30 mm, and assume two parallel lines perpendicular to the cutting line and spaced at a distance of 30 mm, excluding the section between the two lines. Conductive carbon paint is applied to the right and left, respectively, and used as electrodes. The electric resistance between these electrodes is measured by a Kesley electrometer (type 6100
L) at 20 ° C. and 65% RH. The unit is Ω / □
Indicated by

(3) Image quality Roll the electrostatic recording film at 20 ° C and 50% RH for 5 minutes.
After conditioning for 5 days at 40 ° C. and 80% RH for 5 days, an electrostatic latent image is formed on the surface of the electrostatic recording film by a multi-pin electrode head, and then the electrostatic latent image is visualized by a wet toner developing machine. After drying, a hard copy image was obtained.

(B) Pixel omission Printing was performed at 16 dots / mm, and the number of pixel omissions per 100 mm was measured. 80 or less were good, 81 to 250 were good, and 251 or more were bad.

(B) Pixel Thickness Printing was performed at 16 dots / mm, and the number of pixels per 100 mm was measured. 60 or less good, 61-200 slightly good, 201
More than one piece was regarded as defective.

(C) Image density The solid black image area was measured as a reflection density with a Sakura microdensitometer (model PDM-5), and those having a reflection density of 0.7 or more were evaluated as good, and those having a reflection density of less than 0.7 were evaluated as defective.

(4) Transparency Nippon Seimitsu Optics SPHERS METHOD METER (TYPE SEP-
HS), the total light transmittance at 550 nm was measured.

EXAMPLES Hereinafter, the present invention will be described with reference to examples, but the present invention is not limited thereto. In the examples, the number of parts is all parts by weight.

Further, the dielectric layers having the following compositions were used as the dielectric layers of the examples and the comparative examples.

(Dielectric layer composition) (1) "Kemit" (polyester resin, Toray Industries, Inc.)
80) (2) "Cotax" (acrylic resin, Toray Industries, Inc.)
20 (3) Calcium carbonate 20 The above composition was made into a butyl acetate solution so as to have a solid content of 15%, and applied by a gravure roll coater so that the coating amount after drying was 5 g / m ² .

Example 1 Polyethylene terephthalate having an intrinsic viscosity of 0.62 was added to about 280
C. and extruded onto a cooling drum at about 60.degree. Further, the film was stretched 3.5 times by roll stretching in the longitudinal direction at about 80 ° C., and then subjected to a corona discharge treatment in the air, and then the following water-soluble coating agent was applied.

(Coating composition) Acrylic polymer (a) Methyl methacrylate / ethyl acrylate (50/5
0) An acrylic polymer in which 2.5 parts of a carboxyl group and a methylol group were introduced as a functional group in mol% was used.

Sulfonated polystyrene and / or its salt (b) In the above, sulfonated polystyrene having H ⁺ as the X ion of the SO ₃ X group and having a molecular weight of about 70,000 was used.

The weight ratio of (a) / (b) was 80/20, diluted to 4 wt% with water, and 0.3 parts of colloidal silica having an average particle size of 0.12 μ as inorganic particles was added to 100 parts of solids in the coating composition. The addition was used as a coating.

After applying a coating agent on the discharge-treated surface of the polyethylene terephthalate by a gravure coater, 110 ° C., under the conditions of 10 m / min, stretched 3.5 times in the direction perpendicular to the previous stretching direction, and subsequently stretched 220 times.
Heat treatment at ℃, film thickness 75μm, coating thickness
A biaxially stretched polyethylene terephthalate having an antistatic property of 0.07 μm was obtained. This film had good transparency and antistatic properties without cracks in the coating film, and was excellent in adhesion to the substrate and in slipperiness.

Pd was sputtered on the opposite side of the antistatic layer (A) of the biaxially stretched polyester film thus obtained to obtain a conductive film having a surface electric resistance of 5 × 10 ⁶ Ω / □. The dielectric layer was coated on the conductive film to obtain an electrostatic recording film of the present invention. Table 1 shows the evaluation results.
Shown in

Example 2 In, NH as the X ⁺ ion of the sulfonated polystyrene
An electrostatic recording film of the present invention was obtained in the same manner as in Example 1 except that the material into which ₄ ⁺ was introduced was used. Table 1 shows the evaluation results.

Comparative Examples 1 and 2 The water-soluble coating agent used in Example 1 was applied to one surface of a biaxially stretched heat-set polyester film whose crystal orientation was completed. The coating was performed so that the thickness after drying was 0.1 μm after corona discharge treatment of the film surface, and drying was performed at about 160 ° C. for 2 minutes. An electrostatic recording film was obtained by laminating a conductive layer (C) and a dielectric layer (D) on the opposite side of the antistatic layer (A) of the thus obtained polyester film in the same manner as in Example 1. Was. Table 1 shows the evaluation results. When the image quality was evaluated after the humidity of the electrostatic recording film obtained in the comparative example was stored in the form of a roll, the antistatic layer (A) was transferred to the surface of the dielectric layer (D), resulting in an image defect.

Example 3 Polyethylene terephthalate having an intrinsic viscosity of 0.62 was added to about 285
C. and was extruded onto a cooling drum at about 50.degree. Further, the film was stretched 3.5 times by roll stretching in the longitudinal direction at about 95 ° C., and the water-soluble coating agent used in Example 1 was applied to both surfaces of the film. Then, at 125 ° C, 10 m / min, Then, the film was stretched 3.5 times in the perpendicular direction, and then heat-treated at 220 ° C. to obtain an antistatic biaxially stretched polyethylene terephthalate having a film thickness of 75 μm and a coating thickness of 0.1 μm.

This film had good transparency and antistatic properties without cracks in the coating film, and was excellent in adhesion to the substrate and in slipperiness.

Pd was sputtered on one surface of the biaxially stretched polyethylene terephthalate film thus obtained in the same manner as in Example 1 to obtain a conductive film having a surface electric resistance of 5 × 10 ⁶ Ω / □.

The above-mentioned dielectric layer was applied on this conductive film to obtain an electrostatic recording film of the present invention. Table 1 shows the evaluation results.

 ──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-61-3145 (JP, A) JP-A-61-175642 (JP, A) JP-A-57-653 (JP, A) 213853 (JP, A) JP-A-54-147043 (JP, A) JP-A-57-182751 (JP, A)

Claims (1)

(57) [Claims] 1. An antistatic layer (A), a polyester film layer (B), a conductive layer (C) and a dielectric layer (D) each comprising (A) /
(B) / (C) / (D) or (A) / (B) /
In the electrostatic recording film laminated in the order of (A) / (C) / (D), the above (A) / (B) layer or (A) /
The (B) / (A) layer comprises a polyester film and a polymer binder on one or both sides of the polyester film and a compound represented by the general formula (I): (Where R is hydrogen or a methyl group, X is hydrogen, an alkali metal, an alkaline earth metal or ammonium, R ₁ , R ₂ ,
R ₃ and R ₄ are each hydrogen, halogen, an alkyl group or an alkoxy group. An electrostatic recording characterized by being obtained by applying an antistatic layer mainly composed of a polymer having a repeating unit represented by the following formula as a main component, and then stretching in at least one direction. the film.