PROCESS FOR PREPARATION OF POLYURETHANE USED WITH MAGNETIC MEDIA

摘要

The polyurethane resin for a magnetic recording medium is produced by reacting: (a) a diol of 200-5000 molecular wt. contg. COOX [X = alkali metal or H at the molecular chain; (B) a triol of formula (I) [R = R' = -(CH2)n-(OCH2CH2)m-; n = m = 0-6; R" = -(CH2)l-CH(CH3)-; l = 0-3 having a tertiary amino and a secondary hydroxy gp.; and (c) an organic diisocyanate in the presence of a catalyst or in the organic solvent. The diol is pref. polyester polyol or polyether polyol, and the diisocyanate is pref. 4,4'-diphenylmethane diisocyanate, cyclohexane diisocyanate and/or hexamethylene diisocyanate. The polyurethane resin has a good adhesiveness and dispersibility.