# US 4,394,420 A · Magnetic recording medium

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- Number: US 4,394,420 A
- Document ID: US4394420A
- Status: Granted
- Kind: A
- Application number: 06/316,407
- Filed: 1981-10-29
- Granted: 1983-07-19
- Earliest claimed: 1980-11-19
- Assignees: TDK Electronics Co., Ltd.
- Inventors: Kiminori Tamai; Masashi Hayama
- Web page: https://patentgrep.com/patent/US4394420A

## CPC

- G11B 5/71: characterised by the lubricant
- G11B 5/7028: {Additives, e.g. crosslinking agents}
- Y10S 428/90: Magnetic feature
- Y10T 428/31663: As siloxane, silicone or silane
- 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 having a magnetic layer comprises a magnetic powder, a binder, a nonionic or anionic surfactant and a silicone oil having a viscosity of 500 c.s. or lower.

## Claims

### Claim 1

In a magnetic recording medium having a magnetic layer which comprises a magnetic powder, a binder and a nonionic or anionic surfactant in an amount of 1.0 to 5.0 wt. % based on said magnetic powder, the improvement comprising within said magnetic layer of 0.5 to 5.0 wt. % based on said binder of a silicone oil of the formula ##STR2## where n is a value such that the viscosity of the silicone oil is 500 c.s. or lower at 25.degree. C., whereby the blooming of the surfactant and the plasticization of the magnetic layer are diminished.