| 摘要 |
<p>977,797. Magnetic structures. AMPEX CORPORATION. Sept. 30, 1963 [Oct. 15, 1962], No. 38426/63. Heading H1H. A magnetic recording tape comprises a base (e.g. of polyethylene terephthalate) and an adherent coating including a magnetic pigment (e.g. acicularγFe 2 O 3 ) in a binder comprising a polyurethane resin made by reacting p<SP>1</SP>p<SP>1</SP> diphenylmethane diisocyanate, adipic acid and butanediol-1,4 and wherein the composition contains at least an equivalent weight of the diol based on the diisocyanate. The binder may also comprise up to 95 % of a copolymer of vinylidene chloride and acrylonitrile. Solvents e.g. tetrahydrofuran and toluene are used, and a surfactant (e.g. lecithin, lead naphthenate, calcium naphthenate or a N-alkyl trimethyleneamine) may be included. Lubricants e.g. silicone oils, hydrocarbon oils and paraffin wax may be included as may carbon.</p> |
