Disclosed herein are salicylic acid copolymers having a weight average molecular weight of 500 10,000 and obtained (a) by condensing salicylic acid (i) with a benzyl alcohol (ii) and/or benzyl ether (iii) or a benzyl halide (iv) in the presence of an acid catalyst or (b) by reacting a co-condensation resin of (i) and (ii) and/or (iii) with (iv) or (c) by reacting a co-condensation resin of (i) and (ii) and/or (iii) or (iv) with a styrene derivative in the presence of an acid catalyst; multivalent metal salts of the salicylic acid copolymers; color-developing agents comprising the multivalent metal salts; and color-developing sheets suited for pressure-sensitive copying paper and comprising the color-developing agents. Their production processes are also disclosed.
本文公开了
水杨酸共聚物,其重量平均分子量为 500 10、000 的
水杨酸共聚物;(a)在酸催化剂存在下,将
水杨酸(i)与
苄醇(ii)和/或
苄醚(iii)或苄基卤化物(iv)缩合而得,或(b)将(i)和(ii)和/或(iii)的共缩合
树脂与(iv)反应而得,或(c)在酸催化剂存在下,将(i)和(ii)和/或(iii)或(iv)的共缩合
树脂与
苯乙烯衍
生物反应而得;
水杨酸共聚物的多价
金属盐;由多价
金属盐组成的
显色剂;以及由
显色剂组成的适用于压敏复印纸的显色薄片。此外,还公开了它们的生产工艺。