# US 4,400,435 A · Magnetic recording medium

> Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt

- Number: US 4,400,435 A
- Document ID: US4400435A
- Status: Granted
- Kind: A
- Application number: 06/283,549
- Filed: 1981-07-15
- Granted: 1983-08-23
- Earliest claimed: 1980-07-22
- Assignees: TDK Electronics Co., Ltd.
- Inventors: Kuniichi Yoda; Takehisa Ohkawa; Hitoshi Azegami
- Web page: https://patentgrep.com/patent/US4400435A

## CPC

- G11B 5/7022: {containing mixtures of polyurethanes or polyisocyanates with other polymers}
- Y10S 428/90: Magnetic feature
- Y10T 428/31609: Particulate metal or metal compound-containing
- G11B: INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER (recording measured values in a way that does not require playback through a transducer G01D9/00; recording or playback apparatus using mechanically marked tape, e.g. punched paper tape, or using unit records, e.g. punched or magnetically marked cards G06K; transferring data from one type of record carrier to another G06K1/18; circuits for coupling output of reproducer to radio receiver H04B1/20; gramophone pick-ups or like acoustic electromechanical transducers or circuits therefor H04R)
- Y10S: TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y10T: TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION

## Abstract

A magnetic recording medium comprises a substrate coated with a magnetic layer comprising a magnetic powder and a binder comprising an urethane resin and a vinyl chloride-vinyl acetate-maleic acid copolymer having a content of maleic acid component of at least 1.5%.

## Claims

### Claim 1

A magnetic recording medium which comprises a substrate coated with a magnetic layer comprising a magnetic powder and a binder comprising an urethane resin and a vinyl chloride-vinyl acetate-maleic acid copolymer having a content of maleic acid component of at least 1.5%.

### Claim 2 (depends on 1)

The magnetic recording medium according to claim 1 wherein said urethane resin is an urethane elastomer.

### Claim 3 (depends on 1)

The magnetic recording medium according to claim 1 wherein said urethane resin is an urethane prepolymer.

### Claim 4 (depends on 1, 2, 3)

The magnetic recording medium according to claim 1, 2 or 3 wherein said binder further comprises a polyisocyanate.

### Claim 5 (depends on 1)

The magnetic recording medium according to claim 1 wherein said vinyl chloride-vinyl acetate-maleic acid copolymer comprises 20 to 95% of vinyl chloride component; 80 to 5% of vinyl acetate component; and 1.5 to 5.0% of maleic acid coponent.

### Claim 6 (depends on 1)

The magnetic recording medium according to claim 1 wherein said vinyl chloride-vinyl acetate-maleic acid copolymer is incorporated at a ratio of 20 to 90 wt.% based on said binder.