Abstract: 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.

Abstract: 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.

Abstract: 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,R.sub.1 is an alkyl group selected from --CH.sub.3 and ##STR2## wherein n1=1-10, R.sub.2 is an alkylene group which may be --CH.sub.2).sub.nl or ##STR3## n2=1-4 and n3=0-4, R.sub.3 may be selected from --H and --CH.sub.3, n5=0 or 1, and X is a linking group which is stable under electron beam irradiation and may be, for example, ##STR4## R.sub.4 =C1-6 alkylene, for example, with the proviso that when d=0, there is at least one additional polymer in the binder.

Abstract: 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,R.sub.1 is an alkyl group selected from --CH.sub.3 and --(CH.sub.2).sub.n1 CH.sub.3 wherein n1=1-10,R.sub.2 is an alkylene group which may be --CH.sub.2).sub.n1 or --CH.sub.2).sub.n2 (CH)(CH.sub.2).sub.n3 CH.sub.3, n2=1-4 and n3=0-4,R.sub.3 may be selected from --H and --CH.sub.3, n5=0 or 1, and X is a linking group which is stable under electron beam irradiation and may be, for example, ##STR2## R.sub.4 =C1-6 alkylene, for example, with the proviso that when d=0, there is at least one additional polymer in the binder.

Abstract: 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.

Abstract: 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,R.sub.1 is an alkyl group selected from --CH.sub.3 and --(CH.sub.2).sub.nl CH.sub.3 wherein nl=1-10,R.sub.2 is an alkylene group which may be (CH.sub.2).sub.n1 or (CH.sub.2).sub.n2 (CH)(CH.sub.2).sub.n3 CH.sub.3, n2=1-4 and n3=0-4,R.sub.3 may be selected from --H and --CH.sub.3, n5=0 or 1, and X is a linking group which is stable under electron beam irradiation and may be, for example, ##STR2## R.sub.4 =C1-6 alkylene, for example, with the proviso that when d=0, there is at least one additional polymer in the binder.

Abstract: 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.

Abstract: 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.