| 摘要 |
PURPOSE:To improve dispersibility of a magnetic powder in a magnetic coating and surface appearance of the coating film, by incorporating a partially oxidized nitrocellulose and particular polyisocyanate simultaneously as a binder in the magnetic coating. CONSTITUTION:A partially oxidized nitrocellulose with a carboxyl group content of at least 2mmol/100g of nitrocellulose and 1,8-diisocyanato-4-isocyanatometh yloctane (hereinafter referred to as triisocyanate) are used simultaneously as a binder in a magnetic coating consisting mainly of a magnetic powder and a binder. The triisocyanate is a trifunctional polyisocyanate of the formula. Said partially oxidized nitrocellulose is prepd. by oxidation of common nitrocellu lose with an oxidant (e.g., nitrogen oxides, chlorates). Said triisocyanate is used in an amt. of about 0.1-1.0 isocyanate equivalent based on 1 equivalent total of the active hydrogen equivalent of the partially oxidized nitrocellulose and that of other resins used simultaneously.
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