# US 4,391,877 A · Magnetic recording medium

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- Number: US 4,391,877 A
- Document ID: US4391877A
- Status: Granted
- Kind: A
- Application number: 06/359,421
- Filed: 1982-03-18
- Granted: 1983-07-05
- Earliest claimed: 1981-03-23
- Assignees: TDK Electronics Co., Ltd.
- Inventors: Fujio Shibata; Hiroshi Kawahara; Hitoshi Azegami
- Web page: https://patentgrep.com/patent/US4391877A

## CPC

- G11B 5/71: characterised by the lubricant
- Y10S 428/90: Magnetic feature
- Y10T 428/31678: Of metal
- 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 including a substrate having a magnetic coating layer thereon, said magnetic coating layer comprising ferromagnetic particles dispersed in a binder vehicle, characterized in that the magnetic coating layer contains one or more ketones selected from the compounds expressed by the general formula ##STR1## wherein R.sub.1 and R.sub.2 represent saturated or unsaturated chain aliphatic radicals, both or either of which have 11 to 22 carbon atoms and may contain hydroxyl, carboxyl or amino groups.

## Claims

### Claim 1

A magnetic recording medium including a substrate having a magnetic coating layer thereon, said magnetic coating layer comprising ferromagnetic particles dispersed in a binder vehicle, characterized in that the magnetic coating layer contains one or more ketones selected from the compounds expressed by the general formula ##STR12## wherein R.sub.1 and R.sub.2 represent saturated or unsaturated chain aliphatic radicals, both or either of which have 11 to 22 carbon atoms and may contain hydroxyl, carboxyl or amino groups.

### Claim 2 (depends on 1)

A magnetic recording medium according to claim 1, wherein said ketone is present in an amount from 0.1 to 2% based on the weight of the ferromagnetic particles.

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

A magnetic recording medium according to claim 1 or 2, wherein said ketone is selected from the group of ##STR13##

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

A magnetic recording medium according to claim 1, 2 or 3, wherein said ferromagnetic particles are acicular particles of an alloy composed chiefly of iron.