| 摘要 |
<p>1511276 Magnetic coatings BASF AG 5 Sept 1975 [6 Sept 1974] 36607/75 Headings C3B and C3R A magnetic recording medium comprises a non-magnetic base to which is applied a coating consisting of a dispersion of a magnetic pigment in a binder which contains by wt. 50-100% tetrahydrofuransoluble NCO - free thermoplastic polyurethane (U) of high surface-hardness and elasticity-modulus, made by reacting: 1 mole of (A) OH-containing polyester(s) and/or polyether(s) of MW600-4000; 3À5-15 moles (B) aliphatic C2-10 diols, 60-100% mole of which is branched-chain C4-10 diol; 0-1 mole (C) C3-18 aliphatic polyol(s) containing 3-6 OH groups; and 4À5-18 moles (D) a C6-30 diisocyanate; where, based on moles (B) there is #15% moles (C), and total NCO groups # total OH groups in (A), (B) and (C). (B) may comprise HOCH2-CR<1>R<2>-CH2OH where R<1> is C1-4 alkyl and R<2> is H or C1-4 alkyl. (U) may be dissolved in tetrahydrofuran, dioxane, cyclohexanone, or ethyl-glycol acetate, optionally blended with acetone, ethyl acetate or toluene. Phenoxy resins, vinyl chloride polymers or polyvinyl formals may be included.</p> |
