JPS61151542A - Transparent electrostatic recording material - Google Patents

Abstract

PURPOSE:To ensure recording characteristics unaffected by humidity and superior in transparency by forming a conductive layer composed of stannic oxide fine powder and an adhesive resin, and a dielectric layer composed of a dielectric resin and a fine org. or inorg. pigment powder. CONSTITUTION:The conductive layer 2 and and the dielectric layer 3 are succes sively formed o at least one side of a transparent plastic film 1 to form the electrostatic recording material, and the layer 2 is made of fine stannic oxide powder and an adhesive resin, and doped with antimony in an amt. of 1-20ps.wt. per 100pts.wt. of stannic oxide, and has a resistivity of 10<-2>10<1>OMEGA.cm measured at a pressure of 150kg/cm<2> and an average particle diameter of <=0.1mum. The layer 3 is made of a dielectric resin and a fine org. or inorg. pigment powder in a mixing ratio of 80/20-97/3. It is preferred to coat the film 1 with the layer 2 so as to control surface resistivity of 1.0X10<5>-1.0X10<7>OMEGA and to form the layer 2 usually in an amt. of 0.5-5.0g/m<2>. It is suitable to form the layer 3 by coating in an amt. of 3-10, usually, 4-7g/m<2> after drying.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Field of Application) The present invention is applicable to electrostatic recording materials, especially the recent CA D (Compute
erAided Design) This refers to a recording medium suitable for high-resolution electrostatic recording that has begun to be used in electrostatic printers that output drawings, and can be used as a master for diazo copies after recording, or as a partial An object of the present invention is to provide an electrostatic recording medium with excellent transparency, which allows the drawings to be overlapped and the entire drawing to be seen through.

(Prior Art) Electrostatic recording has excellent recording speed and storage stability, and is widely used in the fields of facsimiles and printers.

Recently, with the development of computers, CAD (Computer Design) allows computers to design electronic parts, machinery, buildings, etc., and outputs the results to a pen plotter.
r Aiaea Design) technology has been developed.

However, the plotter takes several minutes to 10 minutes for complex drawings.
It takes several minutes, or even longer in some cases, which poses a problem in terms of work efficiency.

To solve this problem, electrostatic printers using an electrostatic recording method are used.

In addition, in such fields, multiple drawings may be required, and in such cases, diazocopy is the main method used, so transparent or semi-transparent electrostatic recording materials are required. is necessary.

In order to increase the copying speed of diazocopy and to improve the elimination of background, an electrostatic recording medium with as high transparency as possible has been required.

Furthermore, recently, for example, in the design of IC, I, and SI, it is necessary to output multiple photomasks and overlap them to see the entire circuit. It has become necessary.

Such electrostatic recording materials use a highly transparent plastic film as the support, and the conductive layer uses an anionic or cationic polymer ionophore alone or in combination with a highly transparent adhesive. However, it has been proposed to use a mixture of a dielectric resin and a small amount of pigment in the dielectric layer.

However, the conductivity of anionic or cationic polymer electrolytes is affected by humidity, so
Electrostatic recording materials using these conductive agents also have the disadvantage that conductivity decreases at low humidity, making it difficult to record. 150 kgk as a method to improve humidity dependence of electrostatic recording
A conductive layer can be formed by utilizing the electronic conductivity of metal oxides such as zinc oxide, which have a specific resistance of 10-2 to 10 Ω under a pressure of It has the disadvantage of low transparency because it is blended in large amounts.

The conductive layer can also be formed by vacuum deposition of Sn021InzoatCuI or the like, but this has drawbacks such as insufficient transparency and high cost.

(Objective of the Invention) The present invention solves the above-mentioned drawbacks, and provides an electrostatic recording medium whose recording characteristics are not affected by humidity, allowing stable recording from low humidity to high humidity, and which has excellent transparency. It is intended to.

(Means for Solving the Problems) The present invention provides (1) an electrostatic recording material in which a conductive layer and a dielectric layer are sequentially provided on at least one side of a transparent plastic film, wherein the conductive layer is made of 100% tin oxide; It is doped with 1 to 20 parts by weight of antimony, and has a specific resistance value of 10 when measured under a pressure of 150 krc/.
-6D in 2 to 10" ohm, and average particle size 0.1μ
The dielectric layer is made of a fine powder of stannic oxide and an adhesive resin, and the dielectric layer is made of a dielectric resin and an organic or inorganic fine powder pigment, and the mixing ratio of the dielectric resin and the fine powder pigment is 80/2.
The present invention relates to a transparent electrostatic recording material characterized in that it has a molecular weight of 0 to 97/3.

Hereinafter, the configuration of the present invention will be explained with reference to the drawings.

FIG. 1 is a conceptual cross-sectional view of one example of the single-sided electrostatic recording material of the present invention, in which a conductive layer 2 and a dielectric layer 3 are sequentially provided on one side of a transparent plastic film 1.

FIG. 2 is a conceptual cross-sectional view of one example of the double-sided electrostatic recording material of the present invention, in which conductive layers 2 and 2' and dielectric layers 3 and 3' are sequentially provided on both sides of a transparent plastic film 1. ing.

With a single-sided electrostatic recording medium, only one drawing can be recorded and developed, but with a double-sided electrostatic recording medium, two drawings can be obtained at the same time, or by recording and developing once and then recording and developing on the opposite side. This is very effective when it is necessary to superimpose and see through the images.

The transparent plastic film to be used as a support is made by melting and thinning resins such as polyethylene resin, polypropylene resin, polystyrene resin, polyacrylate resin, polymethacrylate resin, polycarbonate resin, polyester resin, and polyvinyl chloride resin. use something

The antimony-doped stannic oxide fine powder must have an average particle size of 0.1 μ or less and a specific resistance of 10 to 10 Ω·α under a pressure of 6'l, 150 klVcm. The fine powder is produced by adding a solution consisting of a mixture of stannic chloride and antimonochloride dissolved in JP-A-57-1998 to heated water to precipitate stannic oxide containing antimony. be able to.

If the antimony content is 1% by weight or less based on tin oxide, the specific resistance value measured under a pressure of 150ψ- will be 10.
It cannot be used for transparent conductive layers because it exceeds Ω. If the antimony content is 20 weight upwind relative to the stannic oxide, it is not suitable because the powder becomes more colored and the transparency decreases.

Therefore, the amount of antimony is 1 to 20% relative to stannic oxide.
It is a weight ratio.

Adding stannic oxide powder to an aqueous solution of an antimony compound,
After drying, it is baked at about 700℃ to 150ψ-
Under the pressure of degrades and becomes unusable.

Therefore, the stannic oxide powder used for the transparent conductive layer contains antimony in a weight ratio of 1 to 20% relative to the stannic oxide, has an average particle size of 0.1μ or less, and is measured under a pressure of 150 μm or less. It is necessary that the specific resistance is 10 to 10Ω.

The adhesive to be used in combination with the fine powder of stannic oxide can be either a water bath adhesive or an adhesive dissolved in an organic solvent; however, if the organic solvent dissolves the plastic film of the support, the coating process may be difficult. Naturally, it cannot be used because of the above problems.

Moreover, if the adhesive dissolves in the organic solvent in the dielectric layer coating, it will cause a problem in the coating operation, so the adhesive for the conductive layer must contain at least a portion of the adhesive that is insoluble in organic solvents.

Examples of water-soluble adhesives include polyvinyl alcohol, oxidized starch, methylcellulose, human 90xethylcellulose, carboxymethylcellulose, inbutylene-maleic anhydride copolymer, styrene-maleic acid copolymer,
Styrene-acrylic acid copolymer, polyacrylamide,
In addition to gelatin, gum arabic, polystyrene sulfonate, polyacrylate, polyvinyl phosphonate,
Anionic conductive resins such as polyvinyl trimethylammonium chloride 9, polydimethyldiallylammonium chloride, styrene/acrylic acid trimethylaminoethyl chloride, and the like can also be used.

In order to improve adhesion to plastic films, polyvinyl acetate, vinyl acetate-acrylic copolymer, acrylate copolymer, methacrylic acid copolymer, polyvinyl chloride, polyvinyl chloride IJ den, polyester, Emulsions of polyurethane, styrene-butadiene copolymers, etc. can also be used.

If the emulsion is used alone as an adhesive, it may dissolve in the organic solvent of the dielectric layer coating, so it is desirable to use it in combination with the water-soluble adhesive.

Examples of organic solvent-soluble adhesives include vinyl acetate resin, ethylene-vinylidene acetate copolymer resin, vinyl chloride resin, vinyl chloride-vinyl acetate copolymer resin, vinylidene chloride resin, vinyl chloride/vinylidene chloride copolymer resin, and acrylic acid ester. Resins such as resins, methacrylic acid ester resins, butyral resins, silicone resins, polyester resins, vinylidene fluoride resins, nitrocellulose resins, styrene resins, styrene-acrylic copolymer resins, urethane resins, etc. can be used, but the plastic of the support It is necessary to select and use a material that has good adhesion to the film.

The stannic oxide powder and the water-soluble adhesive or organic solvent-soluble adhesive are mixed in a ratio of usually 40:60 to 95:5, preferably 65:35 to 85:15,
A conventional pigment dispersing machine such as a colorless digilver, a kneader, a kedimir, an attritor, an into conditioner, a sun 1 mill, a ball mill, etc. can be used to uniformly disperse the pigment to form a conductive paint.

The conductive paint is applied to a plastic film using a commonly used bar coating method, gravure roll coating method, air knife coating method, blade coating method, or roll coating method, and is dried to form a conductive layer.

The conductive layer has a surface electrical resistance of 1. OX 105-1. OX
It is appropriate to apply the coating so that the resistance is 107Ω, which is usually in the range of 0.5 to 5.097Ω.

If the coating amount is too large, the transparency will decrease, so it is better to use it closer to the lower limit of the above range.

A dielectric layer is provided over the conductive layer. The paint forming the dielectric layer can be obtained by mixing a dielectric resin and a pigment.

Examples of the dielectric resin include vinyl acetate resin, ethylene-vinyl acetate copolymer resin, vinyl chloride resin, vinyl chloride-vinyl acetate copolymer resin, vinylidene chloride resin, vinyl chloride-vinylizoy chloride copolymer resin, acrylic acid ester resin, Methacrylic acid ester resin, butyral resin, silicone resin,
Resins such as polyester resin, hynylidene fluoride resin, nitrocellulose resin, styrene resin, styrene/acrylic copolymer resin, urethane resin, etc. can be used.

Most resins can be used as long as they have a volume electrical resistivity of 10 Ω or more, but the combination in which the dielectric layer paint dissolves the conductive layer is a combination that reduces the conductivity of the conductive layer, and the coating and drying method. During operation, the conductive layer will dissolve into the dielectric layer paint, which will reduce the quality of the dielectric layer paint and should be avoided.

Pigments that can be used in the dielectric layer include: Inorganic pigments include calcium carbonate, clay, calcined clay, talc, lithopone, barium sulfate, silicic anhydride, mica, etc.; organic pigments include polyethylene powder, polypropylene powder, Examples include epoxy powder, starch, cellulose powder, etc., and highly opaque pigments such as titanium oxide and zinc oxide are not preferred.

Dielectric resin and pigment generally have a ratio of 60:40 to 97:3
They are preferably mixed at a ratio of 80:20 to 95:5 and uniformly dispersed using a dispersing machine such as an attritor, ball mill, paint conditioner, or sand mill.

The blending ratio of dielectric resin and pigment is pencil, ball-! ′／
It is better to increase the pigment ratio in order to provide writing suitability for signboards/printers and to improve recording quality, but in order not to impair transparency, the pigment ratio should be lower. vinegar,
It is necessary to keep it below 20%. However, if the pigment ratio is lowered in order to increase transparency, the gap between the electrode formed by the pigment particles and the surface of the dielectric layer becomes narrow, making it difficult to obtain uniform recording. For this purpose, the pigment ratio needs to be 3 or more.

The paint for the dielectric layer thus obtained is applied onto the conductive layer using the generally used par coating method, gravure roll coating method, blade coating method, or roll coating method, and then dried. to form a dielectric layer.

The weight of the dielectric layer after drying is 3~10! j/4rL2, preferably 4 to 7 fj/m2.

The electrostatic recording material of the present invention thus obtained has excellent transparency and good recording quality.

(Example) Example 1 A solution of 58 g of stannic chloride and 7 I of antimony chloride dissolved in 100 cc of methanol is dropped into 1 liter of hot water at 90° C. with strong stirring to precipitate antimony-containing tin oxide. The obtained powder is separated from P, washed, and heated at about 500° C. for 2 hours to dope antimony into the tin oxide crystals.

The powder thus obtained contained 10 parts of antimony, had a specific resistance of 1.0 Ω·min under a pressure of 150 kg AML2, and a particle size of 0.06 μm or less.

This conductive powder 7I, 5.0 g of a 30% solution of polyester resin (Pyronal, manufactured by Toyobo), and a 10% solution of polyvinyl alcohol (PVA 117 manufactured by Kuraray) 15
Mix 33g of water and 33p of paint conditioner.
The mixture was dispersed for a minute to obtain a conductive paint.

The paint thus obtained was applied onto a 75 μm polyester film so that the weight after drying was 2.01/m 2 . Its surface resistance is 20'C101RH2
0°C90%RH (D humidity range Te1.0x106~3x
It was 106Ω.

It was measured using a transmission type densitometer manufactured by Tokyo Kohden Co., Ltd. The light transmittance was 80%. , the dielectric layer paint is acrylic resin (LR
-338 Mitsubishi Rayon) 40% solution 23.9 and calcium carbonate (MS-100 Nitto Funka) 0.7,9.
It was obtained by mixing Truf 161i and dispersing it in paint conditioner for 10 minutes.

The paint thus obtained was applied onto the conductive layer so that the weight after drying was 5.09/L''K, and dried to obtain an electrostatic recording material.

This electrostatic recording medium was used as an electrostatic recording medium manufactured by Seiko Electronics Co., Ltd.
When recording was performed on EP-2100, good recording with recording densities of O, SO or higher was obtained in the range from 200G 10% RH to 20° C. 90% RH.

The light transmittance of the obtained electrostatic recording material was 70 cm, and the transparency was good.

Examples 2 and 3. Comparative Examples 1 and 2゜The antimony content ratio of 10% in Example 1 was changed to 0.5! (Comparative Example 1), 5 parts (Example 2), 20 parts (Example 3), and 30 parts (Comparative Example 2), except that the same operation as in Example 1 was performed to obtain an electrostatic recording material. Characteristic measurements similar to those in Example 1 were performed on this electrostatic recording material. The results are shown in Table 1.

When the content of antimono is 5 yen, 150 kVcIr
Although the specific resistance at L2 is high, it is at a usable level (
Example 2) In addition, when the amount of antimony is 20%, the specific resistance is low and the recording quality is good, but the transparency decreases (Example 3) On the other hand, when the amount of antimony is 0.5 In the case of antimono, the specific resistance becomes high and the surface electrical resistance of the conductive layer is also high, so it cannot be used without recording defects (Comparative Example 1).In addition, when the amount of antimono is 30%, the specific resistance is low and the recording quality is also good. However, the transparency was considerably reduced and it was not practical (Comparative Example 2)
).

Example 4.5. Comparative Example 3.4゜ On the conductive layer of Example 1, the acrylic resin/calcium carbonate ratio of 93/7 of the dielectric layer paint of Example 1 was replaced with 70/30.
(Comparative Example 3), 80/20 (Example 4), 97/3 (
Example 1 except that Example 5) and 9V1 (Comparative Example 4) were replaced.
An electrostatic recording medium was obtained by performing the same operation as above.

Characteristic measurements similar to those in Example 1 were performed on this electrostatic recording material. The results are shown in Table 1.

When the mixing ratio of acrylic resin and calcium carbonate was 8V20 (Example 4) and 97/3 (Example 5), the recording quality was good and the transparency was also good. On the other hand, when the blending ratio is 70/30 (Comparative Example 3),
Transparency is low, it is not practical, and the blending ratio is 9V
1 (Comparative Example 4), gaps occurred in the recording and it was not practical.

As explained in detail above, all of the electrostatic recording materials obtained in the Examples of the present invention provided recorded images with high density from low humidity to high humidity and had good transparency.

[Brief explanation of the drawing]

FIG. 1 is a conceptual cross-sectional view of a transparent single-sided electrostatic recording medium of the present invention, and FIG. 2 is a conceptual cross-sectional view of a transparent single-sided electrostatic recording medium.

Claims (1)

[Claims] In an electrostatic recording material comprising an isoelectric layer and a dielectric layer sequentially provided on at least one side of a transparent plastic film, the dielectric layer contains 1 part by weight of antimony per 100 parts by weight of stannic oxide.
~20 parts by weight doped, 150 kg/
The specific resistance value measured under a pressure of cm^2 is 10^-^2 ~
10^1 Ω cm and an average particle size of 0.1 μ or less, the dielectric layer is made of a fine powder of tin oxide and an adhesive resin, and the dielectric layer is made of a dielectric resin and an organic or inorganic fine powder pigment. The mixing ratio of dielectric resin and fine powder pigment is 80-97/
3. A transparent electrostatic recording material characterized by: