Minnesota Mining and Manufacturing Company

John G Chernega

John A Martens

Roger A Olsen

Felix P Lau

Auburn B Cottingham, Deceased

Leslie M Milner

Verna M Kubik

Auburn B Cottinham, Deceased

A magnetic recording medium comprising a nonmagnetizable substrate and a magnetizable layer coated onto the substrate. The magnetizable layer comprises about 83 to 89 percent by weight of acicular, substantialy dendrite-free, iron oxide magnetic pigment particles dispersed in a polymeric binder.

Magnetic recording medium comprising acicular dendrite free iron oxide

Stretched surface recording disk (SSR) 10 comprising an annular support 12 having raised annular ridges 28 and 42 at its inside and outside diameters 22 and 30 with a base portion 24 in between the two ridges, and an annular recording medium film 14 held in radial tension and stretched across the base portion by adhering the film to attachment surfaces 48 and 36 near the inside and outside diameters respectively. The bond between the recording medium film and the support at the inner and outer attachment surfaces is formed by an electron beam cured adhesive such as a mixture of hydantoin hexacrylate and dimethylacrylamide. By manufacturing the stretched surface recording disks with the e-beam process, significantly less time is required to adhere each stretched recording medium to its support, and the quality of the bond between the support and recording medium film is improved. SSR are capable of higher bit density than floppy disks of equivalent surface area and are not as sensitive to contact between the media and a flying magnetic head ('head crashes') as rigid disks.

Method for making stretched surface recording disk

Magnetic recording media have been made with a new class of binder resins having the formula ##STR1## wherein the portion of the copolymer having the a subscript comprises 50 to 97 weight percent of the copolymer, the portion of the copolymer having the b subscript comprises 0 to 30 weight percent of the copolymer, the portions of the copolymer having the =c and d subscripts combined comprise 0.1 to 20 weight percent of the copolymer, while d can be 0,

Magnetic recording medium manufacturing process

Magnetic recording media have been made with a new class of binder resins having the formula ##STR1## wherein the portion of the copolymer having the a subscript comprises 50 to 97 weight percent of the copolymer, the portion of the copolymer having the b subscript comprises 0 to 30 weight percent of the copolymer, the portions of the copolymer having the c and d subscripts combinec comprise, 0.1 to 20 weight percent of the copolymer, while d can be 0,

Electron beam curable copolymer useful in recording media

Stretched surface recording disk (SSR) 10 comprising an annular support 12 having raised annular ridges 28 and 42 at its inside and outside diameters 22 and 30 with a base portion 24 in between the two ridges, and an annular recording medium film 14 held in radial tension and stretched across the base portion by adhering the film to attachment surfaces 48 and 36 near the inside and outside diameters respectively. The bond between the recording medium film and the support at the inner and outer attachment surfaces is formed by an electron beam cured adhesive such as a mixture of hydantoin hexacrylate and dimethylacrylamide. By manufacturing the stretched surface recording disks with the e-beam process, significantly less time is required to adhere each stretched recording medium to its suppport, and the quality of the bond between the support and recording medium film is improved. SSR are capable of higher bit density than floppy disks of equivalent surface area and are not as sensitive to contact between the media and a flying magnetic head ('head crashes') as rigid disks.

Stretched surface recording medium

Magnetic recording media have been made with a new class of binder resins having the formula ##STR1## wherein the portion of the copolymer having the a subscript comprises 50 to 97 weight percent of the copolymer, the portion of the copolymer having the b subscript comprises 0 to 30 weight percent of the copolymer, the portions of the copolymer having the c and d subscripts combined comprise 0.1 to 20 weight percent of the copolymer, while d can be 0,

Recording media containing alkyl acrylate copolymers

An improved lubricant system for magnetic recording media such as helical scan video tapes is disclosed. The resulting improved magnetic recording media comprise the usual flexible or rigid backing and a magnetizable layer on the backing, but the lubricant is comprised of an organic compound selected from the group consisting of isomeric carboxylic acids and isomeric alcohols (e.g. iso-stearic acid and iso-stearyl alcohol). A fatty acid ester may be included in the lubricant. A typical composition utilizes 0.5 parts by weight iso-stearic acid per 100 parts of magnetizable material (e.g., cobalt doped ferric oxide particles) and 1 part by weight of isopropyl palmitate per 100 parts of the magnetizable material. Video tapes lubricated with this new system, have shown improved electromagnetic output (e.g., higher signal-to-noise ratios). In addition, they are able to withstand the stop motion of a helical scan video head better than prior known lubricant systems.

Lubricant system for magnetic recording media containing isomeric acids

Flexible magnetic recording tape is lubricated by a thin coating of a fluorinated telechelic polyether polymer having at least one polar group such as --CONHCH.sub.2 CH.sub.2 OH, --COOCH.sub.3, --CH.sub.2 OH, and --COCF.sub.3. This is believed to provide for the first time reliably effective lubrication at 40.degree. C. and 80% relative humidity.

Growing community of inventors

Stillwater, MN, United States of America

John G Chernega