Novel microcapsules are disclosed in which a liquid material which is substantially insoluble in water is enclosed within a solid permeable shell of etherified urea-formaldehyde polymer, prepared by a process which comprises: (a) providing an organic solution comprising said material and a urea-formaldehyde prepolymer in which from about 50% to about 98% of the methylol groups of said prepolymer have been etherified with a C4-C10 alcohol; (b) creating an emulsion of said organic solution in an aqueous solution comprising water and a surface-active agent, wherein said emulsion comprises discrete droplets of said organic solution dispersed in said aqueous solution; (c) causing in situ self-condensation of said urea-formaldehyde prepolymers by adding to said emulsion an acidifying agent and maintaining said emulsion at a pH of between about 0 and about 4 for a sufficient period of time to allow substantial completion of in situ condensation of said resin prepolymers to convert the liquid droplets of said organic solution to capsules consisting of solid permeable polymer shells enclosing said liquid material; and (d) heating said emulsion to a temperature between about 20°C and about 100°C to cause curing of said in situ formed polymers.
本发明公开了一种新型微胶囊,在这种微胶囊中,基本上不溶于
水的液态材料被包裹在由醚化
脲醛聚合物构成的固体可渗透外壳中,其制备过程包括(a) 提供一种有机溶液,该有机溶液包括所述材料和
脲醛预聚物,其中所述预聚物约 50% 至约 98% 的
甲醇基团已被 C4-C10 醇醚化;(b) 在由
水和表面活性剂组成的
水溶液中形成所述有机溶液的乳液,其中所述乳液包括分散在所述
水溶液中的所述有机溶液的离散液滴;(c) 通过向所述乳液中添加酸化剂,并将所述乳液的 pH 值保持在约 0 至约 4 之间足够长的时间,使所述
树脂预聚物的原位缩合基本完成,从而将所述有机溶液的液滴转化为由固态可渗透聚合物外壳组成的胶囊,将所述液态材料包裹起来,从而使所述
脲醛预聚物原位自缩合;以及 (d) 将所述乳液加热至约 20°C 至约 100°C 之间的温度,使所述原位形成的聚合物固化。