| 摘要 |
PURPOSE:To provide a protective composition not obstructing the runnability of a thermal head even if heated to high temp. and preventing a dye transferring to a heat resistance protective layer, prepared by containing polyvinyl butyral, isosyanates and alkali (alkaline earth) metal phosphate. CONSTITUTION:To polyvinyl butyral (A) on a wt. basis, pref. 5-60% of isocyanates (B) (e.g. p-phenylene dissocyanate), pref., 10-40% of alkali (alkaline earth) metal phosphate (C) [pref., a sodium salt and, for example, a compound represented by formula wherein R is 8-30 alkyl or alkylphenyl and (n) is the average addition mol number of ethylene oxide] and, pref. further, 1-10% of filler (pref., Na2CO3, talc, aluminosilicate, clay or zeolite having a particle size of 1-2mum) are componded to obtain an objective composition. |
