JPH0752295B2 - Electrostatic recording sheet - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] The present invention relates to an electrostatic recording sheet, particularly a CAD (Computer Aided Decoder).
sign) by the electrostatic plotter used in the system,
The present invention relates to an electrostatic recording sheet that can be directly output.

[Conventional technology]

As a conductive agent conventionally used for electrostatic recording, polymer No. 4
An ion conductive hydrophilic conductive agent such as a graded ammonium salt or an electron conductive conductive agent such as a conductive zinc oxide powder is known. Among them, the conductivity of the ion conductive type conductive agent is greatly influenced by the environmental conditions of the surroundings. For example, under low humidity conditions, the electrical resistance of the conductive layer increases, and under high humidity conditions, the electrical resistance decreases, which deteriorates the recording quality and, in extreme cases, there is a drawback that recording cannot be performed. Further, under high humidity conditions, the conductive layer absorbs moisture and softens, so that there is a drawback that the conductive layer is peeled off when writing on the recording sheet with a pencil. On the other hand, in the case of the electron conductive type conductive agent, the electric resistance of the conductive layer is not greatly affected by the environment as compared with the ion conductive type, but due to the influence of the environment such as expansion and contraction of the binder used and deterioration with time. The electric resistance of the conductive layer changes, and the recording quality deteriorates.
This effect is particularly remarkable in the case of a hydrophilic binder, but even when a commonly used hydrophobic organic solvent-soluble polymer binder is used, the effects of expansion and contraction due to temperature change, deterioration over time, etc. are unavoidable. Further, in the organic solvent-soluble polymer binder, when the dielectric layer is coated with a solvent on this, a part of the conductive layer is eluted by the solvent, which causes variations in the electric resistance value of the conductive layer and the dielectric recording layer. Recording quality is deteriorated by causing a decrease in electrical resistance.

[Problems to be solved by the invention]

The present invention solves the above-mentioned drawbacks and allows not only the conductive layer and the dielectric layer to be coated with an organic solvent system, but also an electrostatic recording sheet having stable recording characteristics without being affected by temperature and humidity and aging. The purpose is to provide.

[Means for solving problems]

As a result of intensive studies, the present inventors have found that in an electrostatic recording sheet in which a conductive layer and a dielectric layer are laminated in this order on a support, the conductive layer includes an electron conductive type conductive agent and a crosslinkable organic polymer adhesive. It has been found that the above-mentioned object can be achieved by the constitution comprising The conductive layer thus obtained is less affected by the environment,
It has almost no change over time, is not only strong against physical impact, but is also excellent in water resistance and organic solvent resistance. Therefore, an electrostatic recording sheet obtained by providing a dielectric layer on it has It is possible to obtain a stable image with no change.

Conductive layer polymer adhesive used in the present invention is a cross-linking type, urethane resin, acrylic resin, methacrylic resin, acrylic ester resin, methacrylic ester resin, phenol resin, melamine resin, Examples thereof include amino resins such as urea resins, alkyd resins, epoxy resins, organic silicon compounds, butyral resins, petroleum resins and unsaturated polyesters. These resins can be used alone or in combination of two or more. In use, if necessary, heat treatment, UV treatment, electron beam treatment, or a crosslinking agent,
The crosslinking aid is ignited and cured. In addition to the above, a polymer adhesive that is usually known together with the crosslinkable resin, such as vinyl acetate,
In combination with one or more of polymers or copolymers of vinyl chloride, styrene, butadiene, acrylic (methacrylic) acid ester, ethylene, acrylonitrile, etc., silicon resin, polyester resin, polyurethane resin, alkyd resin, epoxy resin, polyolefin, etc. However, in this case, the crosslinkable resin ratio is preferably at least 30% or more.

As the electron conductive type conductive agent, conductive mica, zinc oxide,
Fine powders of tin oxide, indium oxide, titanium oxide, vanadium oxide and the like and metals such as Al and Zn can also be used. The conductive agent is preferably used as fine particles having an average particle size of 0.01-10 μm, preferably 0.05-3 μm. The specific resistance of these conductive agents is 100 Ω / cm ² or less when pressurized, preferably 10 Ω · cm or less, preferably 5
It is preferably Ωcm or less.

In the case of forming a conductive layer, an electron conductive type conductive agent and a crosslinkable organic polymer adhesive in an organic solvent or a coating liquid in which the conductive agent and an emulsion type crosslinkable organic polymer adhesive are dispersed in water. Is applied on a support and the necessary curing is carried out to form. The ratio of the conductive agent and the adhesive can be arbitrarily set, but when the weight ratio is 10-200 parts by weight, preferably 20-150 parts by weight, relative to 100 parts by weight of the conductive agent powder, relatively preferable results are obtained. can get. The coating amount of the conductive layer is 0 as a solid content.
1-3 g / m ² is normal, preferably 0.2-2 g / m ² .

The support used in the electrostatic recording sheet of the present invention,
In addition to organic polymer films, that is, films of polyester, polyolefin, polystyrene, polyvinyl chloride, polycarbonate, polyamide, polyimide, etc., synthetic paper and polyethylene laminated paper can be used. In the case of a transparent or semi-transparent support, by using an electron conductive type conductive agent and a crosslinkable polymer binder having an average particle size of 1 μm or less, there is no influence of the environment and change with time, and electrostatic recording capable of diazo copy You can get a sheet.

In the present invention, the dielectric layer is formed by coating on the conductive layer. It consists of a dielectric resin and an inorganic or organic pigment. Examples of the dielectric resin include polyvinyl chloride,
Polyvinylidene chloride, polyvinyl acetate, polyacrylic (methacrylic) ester, polystyrene, butyral resin, silicone resin, epoxy resin, polyolefin,
One or more types of homopolymers or copolymers such as polyurethane, polyvinyl acetal, and the cross-linking resins mentioned above as the binder of the conductive layer can be used. As the inorganic pigment, for example, kaolin, calcium carbonate, amorphous silica, aluminum hydroxide or the like is used, and as the organic pigment, synthetic resin powder such as polyethylene powder, polystyrene powder or polyester powder can be used.

〔Example〕

Example 1 On one side of a 75 μm thick polyester film (Lumirror # 75 manufactured by Toray), 10 parts by weight of conductive tin oxide (T-1 manufactured by Mitsubishi Metals Co., Ltd.) having an average particle size of 0.1 μm or less, a crosslinked acrylic resin. (ST-106 manufactured by Soken Chemical Industry Co., Ltd., solid content 39%) A coating solution consisting of 23 parts by weight and 70 parts by weight of methyl ethyl ketone was applied by a Mayer bar so that the applied amount after drying was 1.5 g / m ^2. Then
After coating, the cross-linking reaction was completed by leaving it at 140 ° C for 1 hour to obtain a conductive layer. The surface electric resistance of this conductive layer is
It was 3 × 10 ⁶ Ω and was constant at 20 ° C / 10% RH to 20 ° C / 85% RH. Next, on this conductive layer, a polyacrylic ester resin (Haimer SBA720 manufactured by Sanyo Kasei Co., Ltd.
%) 50 parts by weight, calcium carbonate fine powder 3 parts by weight, toluene 50 parts by weight
It was coated at 4.5 g / m ² to obtain a diazo-copyable transparent electrostatic recording sheet. This electrostatic recording sheet was printed using an electrostatic plotter (DRASTEM-8700) manufactured by Toyo Denki Co., Ltd., and as a result, 20 ° C / 10% RH to 20 ° C / 85% RH and 40 ° C / 85
Good recording was obtained at% RH.

Example 2 A semi-transparent synthetic paper having a thickness of 75 μm (manufactured by Oji Yuka Synthetic Paper Co., Ltd., YUPO)
TPG-75), on one side, 10 parts by weight of conductive tin oxide (T-1 manufactured by Mitsubishi Metals Co., Ltd.) having an average particle size of 0.1 μm or less, urethane resin (two-component urethane, manufactured by Nippon Polyurethane Co., Nipporan)
800/1000 = 1/1, solid content 40%) 8 parts by weight, ethyl acetate 40
12 parts by weight of isocyanate (Coronate L made by Nippon Polyurethane Co., solid content 75%) as a cross-linking agent to a coating solution consisting of 40 parts by weight of butyl acetate and a coating amount after drying with a Mayer bar of 1.5 g / Apply to m ² and dry 1
It was left to stand for a day and cured to obtain a conductive layer. The surface electrical resistance of this conductive layer is 3.5 × 10 ^{6 at} 20 ℃ / 10% RH to 20 ℃ / 85% RH.
It became Ω and was constant. Then, a dielectric layer was applied onto this conductive layer in the same manner as in Example 1 to obtain a diazocopyable electrostatic recording sheet. This electrostatic recording sheet was printed using an electrostatic plotter (DRASTEM-8700) manufactured by Toyo Denki Co., Ltd., and as a result, 20 ° C / 10% RH to 20 ° C / 85% RH and 40 ° C / 85
Good recording was obtained at% RH.

Example 3 10 parts by weight of conductive zinc oxide (manufactured by Honjo Chemical Co., Ltd.) having an average particle size of 0.9 μm or less on one side of semi-transparent synthetic paper (Yupo TPG-75 manufactured by Oji Yuka Synthetic Paper Co., Ltd.), reactive acrylic Resin (manufactured by Dainippon Ink and Co., Chris coat, solid content 20%) 100 parts by weight,
2.5 parts by weight of modified polyisocyanate (Crisbon manufactured by Dainippon Ink and Chemicals Inc.) as a cross-linking agent, vinyl chloride vinyl acetate copolymer resin (SEBIAN A # 4114 manufactured by Daicel, solid content 40%)
Apply 8 parts by weight and 15 parts by weight of methyl ethyl ethone with a Mayer bar so that the coating amount after drying will be 1.5 g / m ^2, and allow to cure for 1 day after drying to form a conductive layer. Obtained.
The surface electric resistance of this conductive layer is 20 ℃ / 10% RH ～ 20 ℃ / 85%
It was 3.1 × 10 ⁶ Ω at RH and was constant. Then, a dielectric layer was applied onto this conductive layer in the same manner as in Example 1 to obtain a diazocopyable electrostatic recording sheet. This electrostatic recording sheet is manufactured by Toyo Denki Seisakusho Co., Ltd. electrostatic plotter (DRASTEM-
8700), as a result of printing, 20 ℃ / 10% RH-20 ℃ / 85%
Good recording was obtained at RH and 40 ° C / 85% RH.

Comparative Example 1 A coating liquid consisting of 60 parts by weight of an ion-conducting conductive agent (Chemistat 6300 manufactured by Sanyo Kasei Co., Ltd., solid content 33%) and 80 parts by weight of methanol on one surface of a 75 μm thick polyester film (Lumirror # 15 manufactured by Toray). Was coated with a Mayer bar so that the coating amount after drying was 5.5 g / m ² to obtain a conductive layer. Next, a dielectric layer is coated on this conductive layer in the same manner as in Example 1,
An electrostatic recording sheet was obtained. As a result of printing this electrostatic recording sheet using an electrostatic plotter (DRASTEM-8700) manufactured by Toyo Denki Seisakusho Co., Ltd., 20 ° C / 10% RH, 20 ° C / 85% RH and 40 ° C / 8
Recording was not possible at 5% RH.

Comparative Example 2 A semi-transparent synthetic paper having a thickness of 75 μm (manufactured by Oji Yuka Synthetic Paper Co., Ltd.
TPG-75), on one side, 10 parts by weight of conductive tin oxide (T-1 manufactured by Mitsubishi Metals Co., Ltd.) with an average particle size of 0.1 μm or less, acrylic ester resin (Haimer SBA720 manufactured by Sanyo Chemical Co., Ltd., solid content 45
%) 45 parts by weight and toluene 55 parts by weight was applied by a Meyer bar so that the coating amount after drying was 1.5 g / m ² to obtain a conductive layer. The surface electric resistance of this conductive layer is 5 ×
It was 10 ⁷ Ω (20 ° C./10% RH to 5 × 10 ⁸ Ω (20 ° C./85% RH). Then, a dielectric layer was coated on this conductive layer in the same manner as in Example 1, An electrostatic recording sheet was obtained, which was manufactured by Toyo Denki Seisakusho Co., Ltd. electrostatic plotter (DRASTEM-870).
As a result of printing using 0), recording was defective under any of the test conditions.

Recording: Electrostatic plotter DRASTEM-8700 manufactured by Toyo Denki Seisakusho Co., Ltd. Recording conditions: Low humidity: 20 ° C / 10% RH Medium humidity: 25 ° C / 45% RH High humidity: 20 ° C / 85% RH High temperature / high humidity: 40 ℃ / 85% RH Aging: Recorded after standing for 1 week under the condition set to repeat 20 ℃ / 10% RH and 20 ℃ / 85% RH every 8 hours.

Conductive layer strength: It is a writing test with a pencil under the condition of 20 ° C./85% RH. For example, H in the table indicates that writing is possible up to a pencil having a hardness of H.

〔The invention's effect〕

According to the present invention, the surface electric resistance of the conductive layer is constant without being affected by the environment and changes over time, and besides a stable image can be obtained over a wide temperature and humidity range, further, solvent resistance,
It is possible to provide an electrostatic recording sheet having a tough conductive layer that is excellent in water resistance and is not easily affected by physical influences such as scratches and impacts, whereby extremely stable recording can always be obtained.

Front Page Continuation (72) Inventor Masao Ota 1-10-6 Shinonome, Koto-ku, Tokyo Oji Paper Co., Ltd. (72) Inventor Takashi Ogasawara 1-10-6 Shinonome, Koto-ku, Tokyo Oji Paper Paper Co., Ltd. Product Research Laboratory (72) Inventor Rie Ito 1-10-6 Shinonome, Koto-ku, Tokyo Oji Paper Co., Ltd. Product Research Laboratory (56) Reference JP-A-61-233749 (JP, A) 61-233748 (JP, A) JP-A 61-233747 (JP, A) JP-A 60-242460 (JP, A) JP-A 58-22315 (JP, A) JP-A 58-2848 (JP , A) JP-A-60-33560 (JP, A) JP-A-61-156051 (JP, A) JP-B-58-28574 (JP, B1) JP-B-58-28576 (JP, B1)

Claims (1)

[Claims] 1. An electrostatic recording sheet in which a conductive layer and a dielectric layer are provided in this order on a support, wherein the conductive layer comprises an electron conductive type conductive agent and a crosslinkable organic polymer adhesive. Electrostatic recording sheet.