The present invention relates to a process for synthesizing a particulate copolymer comprising: providing a reaction mixture comprising a reaction medium, a polymerization stabilizer, a water-insoluble ethylenically unsaturated monomer and an ethylenically unsaturated monomer containing hydrophilic functionality, and polymerizing the water-insoluble ethylenically unsaturated monomer and the ethylenically unsaturated monomer containing hydrophilic functionality, wherein said reaction mixture has a viscosity value of at least 10 cps measured at 40°C. The polymerization reaction is preferably conducted at a temperature lower than 100°C and activated by a polymerization catalyst. The resulting particulate copolymer dispersion comprises copolymer particles showing a weight average diameter size in the range of microns and absence of defects, such as coagulant or agglomerates. The present invention also provides a dispersion of a particulate copolymer obtained by using the process described above and a photographic material comprising a support and at least one layer containing a particulate copolymer obtained by using the process described above. The photographic material presents improved physical and optical performance.
本发明涉及一种合成微粒共聚物的工艺,包括:提供一种包含反应介质、聚合稳定剂、不溶于
水的
乙烯基不饱和单体和含有亲
水官能团的
乙烯基不饱和单体的反应混合物,以及聚合不溶于
水的
乙烯基不饱和单体和含有亲
水官能团的
乙烯基不饱和单体,其中所述反应混合物在 40°C 时测量的粘度值至少为 10 cps。聚合反应最好在低于 100°C 的温度下进行,并由聚合催化剂活化。所得到的微粒共聚物分散体包括重量平均直径尺寸在微米范围内的共聚物微粒,且不存在缺陷,如凝结剂或团聚体。本发明还提供了一种通过上述工艺获得的微粒共聚物分散体和一种感光材料,该感光材料包括一个支架和至少一层含有通过上述工艺获得的微粒共聚物的层。该感光材料具有更好的物理和光学性能。