为调控有机颜料微胶囊的粒径及其分布,在分析微悬浮聚合过程粒径变化的基础上,系统研究了微悬浮聚合工艺(均质化剪切速率、搅拌速率)和配方(有机颜料、分散剂含量)对颜料微胶囊粒径的影响。发现当搅拌速率为250r·min。时,单体液滴的融合和乳胶粒的粘并现象均较少,聚合体系可较稳定地保持均质化单体液滴的尺寸。分散剂磷酸三钙TCP用量对体系稳定性影响明显,但其粒径调控能力有限。均质化强度对微胶囊粒径影响明显,具有较好的调控能力,而颜料含量对微胶囊粒径的影响较少。因而通过聚合工艺和配方的综合调节,可制得一系列颜料含量高、粒径分布窄、粒径可调范围较大的“石榴状”有机颜料微胶囊。
Hydrophobic copper phthalocyanine blue organic pigment (PB) can be effectively encapsulated by co-poly(styrene-acrylate) via in-situ micro-suspension polymerization. In order to adjust and control the morphology of pigment microcapsules, the effects of homogenization shear rate, agitation speed, dispersant TCP amount and pigment concentration on the particles size and size distribution of polymerization products were investigated. It was found that there was a critical agitation speed of 250 r ~ min 1 for achieving a stable size and size distribution of dispersed phase during polymerization. TCP amount had a significant effect on the stability of micro-suspension system but a limited effect on particle size control. Homogenization shear rate played an obvious role in controlling particle size, while the effect of pigment concentration on particle size was not obvious. Thus a series of pigment microcapsules with controllable particle size, narrow distribution and high pigment content could be obtained.