# US 4,396,667 A · Electrostatic recording medium

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- Number: US 4,396,667 A
- Document ID: US4396667A
- Status: Granted
- Kind: A
- Application number: 06/213,600
- Filed: 1980-12-04
- Granted: 1983-08-02
- Earliest claimed: 1979-12-04
- Assignees: Matsushita Electric Industrial Co., Ltd.
- Inventors: Nobuo Sonoda; Shigeru Tsubusaki; Wataru Shimotsuma
- Web page: https://patentgrep.com/patent/US4396667A

## CPC

- G03G 5/0202: {Dielectric layers for electrography}
- G03G 5/104: {comprising inorganic material other than metals, e.g. salts, oxides, carbon}
- Y10T 428/24934: including paper layer
- Y10T 428/24942: including components having same physical characteristic in differing degree
- Y10T 428/31895: Paper or wood
- Y10T 428/31906: Ester, halide or nitrile of addition polymer
- Y10T 428/31993: Of paper
- G03G: ELECTROGRAPHY; ELECTROPHOTOGRAPHY; MAGNETOGRAPHY
- Y10T: TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION

## Abstract

An electrostatic recording medium comprising a support, a conductive layer formed on one surface of the support and made of zinc oxide dispersed in a combination of a cationic polyelectrolyte and a non-conductive binder resin, and a dielectric layer formed on the conductive layer. The cationic polyelectrolyte is contained in an amount of not smaller than 30% by weight of the total of the polyelectrolyte and the binder resin.

## Claims

### Claim 1

An electrostatic recording medium comprising a support, a conductive layer coated on one surface of said support, said conductive layer consisting essentially of zinc oxide dispersed in a combination of not less than 30% but not greater than 95% by weight of a cationic polyelectrolyte, with the balance being a non-conductive resin, and a dielectric layer formed on the conductive layer.

### Claim 2 (depends on 1)

An electrostatic recording medium according to claim 1, wherein said cationic polyelectrolyte is an oligomer or polymer having a functional group of the formula ##STR4## where R.sub.1, R.sub.2 and R.sub.3 are independently hydrogen, an alkyl group, an allyl group, an aryl group, an acyl group, or an alkylamino group, and X is a halogen.

### Claim 3 (depends on 2)

A electrostatic recording medium according to claim 2, wherein said oligomer or polymer having the functional group is polyvinylbenzyltrimethylammonium halide or a partial ester of an acrylic acid polymer containing a quaternary ammonium salt.

### Claim 4 (depends on 1)

An electrostatic recording medium according to claim 1, wherein cationic polyelectrolyte is poly-2-vinyl-N-methylpyridinium chloride or polyethyleneimine chloride.

### Claim 5 (depends on 1)

An electrostatic recording medium according to claim 1, wherein said cationic polyelectrolyte has a functional group of the formula ##STR5## in which R.sub.1 and R.sub.2 are independently hydrogen, an alkyl group, an allyl group, an aryl group, an acyl group or an alkylamino group, and X is a halogen.

### Claim 6 (depends on 5)

An electrostatic recording medium according to claim 5, wherein said cationic polyelectrolyte is poly-2-acrylooxyethyldimethylsulfonium chloride or polyvinylbenzylsulfonium chloride.

### Claim 7 (depends on 1)

An electrostatic recording medium according to claim 1, wherein said cationic polyelectrolyte has a functional group of the formula ##STR6## in which R.sub.1, R.sub.2 and R.sub.3 are independently hydrogen, an alkyl group, an allyl group, an aryl group, an acyl group or an alkylamino group, and X is a halogen.

### Claim 8 (depends on 7)

An electrostatic recording medium according to claim 7, wherein said cationic polyelectrolyte is polyvinylbenzylphosphonium chloride or polyglycidyltrimethylphosphonium chloride.

### Claim 9 (depends on 1)

An electrostatic recording medium according to claim 1, wherein said non-conductive resin is a hydrophobic resin or a water soluble resin.

### Claim 10 (depends on 9)

An electrostatic recording medium according to claim 9, wherein said hydrophobic resin is polyvinyl acetate, styrene-butadiene resin or acrylic ester resin.

### Claim 11 (depends on 9)

An electrostatic recording medium according to claim 9, wherein said water-soluble resin is polyvinyl alcohol or hydroxymethyl cellulose.

### Claim 12 (depends on 1)

An electrostatic recording medium according to claim 1, wherein said combination is a combination of polyvinylbenzyltrimethylammonium halide or a partial ester of acrylic acid polymer containing a quaternary ammonium salt polyvinyl acetate.

### Claim 13 (depends on 1)

An electrostatic recording medium according to claim 1, wherein said zinc oxide has a specific resistance ranging from 1.times.10.sup.3 to 1.times.10.sup.4 .OMEGA..multidot. cm.

### Claim 14 (depends on 1)

An electrostatic recording medium according to claim 1, wherein the amount of the cationic polyelectrolyte is not smaller than 50 wt% of the combination.

### Claim 15 (depends on 14)

An electrostatic recording medium according to claim 14, wherein the amount is about 70 wt%.