Magnetic recording medium and magnetic recording and reproducing apparatus

Patent metadata

Field	Value
Publication number	US-10074396-B2
Application number	US-201615264988-A
Country	US
Kind code	B2
Filing date	Sep 14, 2016
Priority date	Sep 18, 2015
Publication date	Sep 11, 2018
Grant date	Sep 11, 2018

Abstract

In a magnetic recording medium of the present invention, an outermost surface of a protective layer 3 on a lubricant layer 4 side contains carbon and nitrogen in a range of 50 atomic % to 90 atomic %, and the lubricant layer 4 is formed by being in contact with the outermost surface, contains compounds A to C represented in the below general formulas (1) to (3) described below, and has a film thickness of 0.5 nm to 2 nm.

R1-C 6 H 4 OCH 2 CH(OH)CH 2 OCH 2 —R2-CH 2 OCH 2 CH(OH)CH 2 OH   (1),

CH 2 (OH)CH(OH)CH 2 OCH 2 CF 2 CF 2 (OCF 2 CF 2 CF 2 ) m OCF 2 CF 2 CH 2 OCH 2 CH(OH)CH 2 OH   (2),

HOCH 2 CF 2 CF 2 O(CF 2 CF 2 CF 2 O)sCF 2 CF 2 CH 2 OCH 2 CH(OH)CH 2 OH   ( 3 )

First claim

What is claimed is:

1. A magnetic recording medium comprising at least a magnetic layer, a protective layer, and a lubricant layer on a nonmagnetic substrate in this order,
wherein an outermost surface of the protective layer on the lubricant layer side contains carbon and nitrogen,
the nitrogen is contained in the outermost surface in a range of 50 atomic % to 90 atomic %,
the lubricant layer is formed by being in contact with the outermost surface, has an average film thickness of 0.5 nm to 2 nm, and contains a compound A represented in the below general formula (1), a compound B represented in the below general formula (2), and a compound C represented in the below general formula (3), and
a mass ratio (A/(A+B+C)) of the compound A with respect to a s of masses of the compounds A, B, and C contain d in the lubricant layer is in a range of 0.05 to 0.6, a mass ratio (B/(A+B+C)) of the compound B with respect to the sum of the masses of the compounds A, B, and C contained in the lubricant layer is in a range of 0.05 to 0.5, and a mass ratio (C/(A+B+C)) of the compound C with respect to the sum of the masses of the compounds A, B, and C contained in the lubricant layer is in a range of 0.05 to 0.9,
R1-C 6 H 4 OCH 2 CH(OH)CH 2 OCH 2 —R2-CH 2 OCH 2 CH(OH)CH 2 OH   (1)

in the general formula (1), R1 is an alkoxy group having 1 to 4 carbon atoms, R2 is —CF 2 O(CF 2 CF 2 O)x(CF 2 O)yCF 2 — (an order in parentheses of x and y may be this order, the opposite order, or a random order (each of x and y is an integer of 0 to 15).)
CH 2 (OH)CH(OH)CH 2 OCH 2 CF 2 CF 2 (OCF 2 CF 2 CF 2 ) m OCF 2 CF 2 CH 2 OCH 2 CH(OH)CH 2 OH   (2)

in the general formula (2), m is an integer in a range of 4 to 50,
HOCH 2 CF 2 CF 2 O(CF 2 CF 2 CF 2 O)sCF 2 CF 2 CH 2 OCH 2 CH(OH)CH 2 OH   (3)

in the general formula (3), s is an integer.

2. The magnetic recording medium according to claim 1 ,
wherein an average molecular weight of the compound A is in a range of 1,000 to 2,500.

3. The magnetic recording medium according to claim 1 ,
wherein an average molecular weight of the compound B is in a range of 1,000 to 2,500.

4. The magnetic recording medium according to claims 1 ,
wherein an average molecular weight of the compound C is in a range of 1,000 to 2,000.

5. A magnetic recording and reproducing apparatus, comprising:
the magnetic recording medium according to claims 1 ;
a medium-driving unit that drives the magnetic recording medium in a recording direction;
a magnetic head that records information to the magnetic recording medium and reproduces information from the magnetic recording medium;
a head-moving unit that moves the magnetic head relative to the magnetic recording medium; and
a recording and reproducing signal-processing unit that processes a recording signal transmitted to the magnetic head and a reproducing signal received from the magnetic head.

Assignees

• Showa Denko Kk

Inventors

• Yamakawa Eishin
• To Katsuaki
• Hayase Saeko

Classifications

• G11B19/28 Primary

  Speed controlling, regulating, or indicating (G11B19/24 takes precedence) · CPC title

• G11B5/72

  Protective coatings, e.g. anti-static {or antifriction} · CPC title

• G11B5/725

  containing a lubricant {, e.g. organic compounds (inorganic carbon protective coating G11B5/727)} · CPC title

• G11B21/106

  on disks · CPC title

• G11B5/7257 Primary

  Perfluoropolyether lubricant · CPC title