Polyurea compositions suitable as 1- pack or 2- pack coatings for a variety of substrates are obtained by reaction of polyisocyanates with secondary aromatic diamines having the formula
wherein R₁ and R₂ each represents an alkyl group having from 4 to 20 carbon atoms.
N,Nʹ-di(2-butyl)-4,4ʹ- methylene dianiline is a suitable diamine, and the polyisocyanate can be a biuret having the formula
Wherein Y is:
a) a polymethylene chain, -(CH₂)n-, in which n is an integer from 2 to 10;
b) a divalent aromatic radical;
c) a cyclohexylene radical; or
d) an aralkylene radical.
聚
异氰酸酯与仲芳香族二胺反应可得到适用于各种基材的单组分或双组分聚
脲组合物,其式为
其中 R₁ 和 R₂ 分别代表具有 4 至 20 个碳原子的烷基。
N,Nʹ-二(2-丁基)-4,4ʹ-亚甲基
二苯胺是一种合适的二胺,而多
异氰酸酯可以是具有以下式子的双缩
脲
其中 Y 是
a) 聚亚甲基链,-(CH₂)n-,其中 n 为 2 至 10 的整数;
b) 二价芳香基
c)
环己烯基;或
d)
芳烃基。