The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Oct. 03, 2000
Filed:
Mar. 30, 1998
Shuji Iida, Nagano, JP;
Kiyoto Fukushima, Nagano, JP;
TDK Corporation, Tokyo, JP;
Abstract
Disclosed is a magnetic recording medium good in production efficiency, paint stability and electromagnetic characteristics, and improved in running properties and durability, which has a magnetic layer formed on a surface side of a non-magnetic support and a backcoat layer formed on a back side thereof, in which said backcoat layer is formed by kneading a compounded composition comprising 50 parts to 120 parts by weight of carbon black (P) per 100 parts by weight of a resin binder (B) (P/B=0.5/1 to 1.2/1), said carbon black (P) having an average particle size of 18 nm to 25 nm and a DBP oil absorption of 90 cc/100 g to 125 cc/100 g, 0.3 part to 2.5 parts by weight of large-sized carbon black or carbon graphite having an average particle size of 150 nm to 500 nm per 100 parts by weight of said carbon black, and a vinyl chloride copolymer as the resin binder, said copolymer containing at least amine-modified vinyl units and acidic functional group-containing vinyl units at the same time, so as to satisfy that the concentration of nonvolatile components is 45 to 60%, and that the P/B is 1.5/1 to 3.5/1, and then, dispersing the kneaded compound by dilution.