流变调节剂在二元喷雾产品中的影响

Impact of rheology modifiers on Bag-on-valve spray products

选择了化妆品中常用的5种流变调节剂(卡波姆,丙烯酰二甲基牛磺酸铵/VP共聚物,聚丙烯酸酯交联聚合物-6,黄原胶和纤维素),分别配制含不同质量分数聚合物的水溶液和乳液体系。采用流变仪及马尔文喷雾粒度分析仪研究流变与喷雾行为。利用激光粒度仪测试各流变剂在水中形成的微凝胶粒径分布,并跟踪了乳液体系的稳定性。分析了流变行为及喷雾效果与流变调节剂在水溶液中的微观结构的关系。结果发现,黄原胶因其分子量较大,激光粒度仪测试其水溶液颗粒相对较大,虽然具有较好的剪切变稀性能,但其法向应力较高,不能提供良好的喷雾性能。卡波姆等其他4种聚合物,微凝胶颗粒较小,卡波姆含量较高时,因微凝胶颗粒致密而相互作用,可提供相对较高的黏度与弹性模量,但不利于喷雾,而聚丙烯酸酯交联聚合物-6因其适中的弹性模量,屈服应力和较低的法向应力,可作为辅助流变调节剂帮助乳液体系稳定,同时可以提供优良的喷雾效果。

The effects of rheology modifiers on the stability and spraying performance of Bag-onvalve spray products were studied.Five rheology modifiers that were commonly used in cosmetics(carbomer,ammonium acryloyldimethyltaurate/VP copolymer,polyacrylate crosspolymer-6,xanthan gum,and cellulose)were studied either alone in water or in a lotion base at different concentrations(0.02%,0.05%,0.10%,and 0.20%).The rheological behavior was investigated with a rheometer.The spraying performance was tested on Malven Panalytic Spraytec.The micro-gel size distribution in water was measured on a laser granulometer.The stability of the lotions containing different rheology modifiers was also monitored for 3 months.The results showed that xanthan gum showed bad spraying performance and provided relatively high normal stress.Cellulose had relatively low normal stress and good spraying performance.Carbomer,acryloyldimethyltaurate/VP copolymer,and polyacrylate crosspolymer-6 had relatively small micro-gel size,which proposed a concentration-dependent rheological response.When used at high concentration,the molecules interacted with each other so that higher viscosity was build up.Good elasticity could also be obtained at high concentration.When used at low concentration,the micro-particles were incompact,especially for cellulose and ammonium acryloyldimethyltaurate/VP copolymer,the spraying performance was good,but the rheological behavior was viscous-like,indicative of bad stability.