可再分散乳胶粉用NMA-苯丙乳液的合成及性能

Preparation of redispersible emulsion powder with NMA-styrene-acrylic latex and performance of the latex

采用半连续种子乳液聚合,以丙烯酸丁酯(BA)、甲基丙烯酸甲酯(MMA)、苯乙烯(St)为主要原料,DSB为乳化剂,KPS为引发剂,通过引入功能性单体甲基丙烯酸(MAA)和交联性单体N-羟甲基丙烯酰胺(NMA),合成了低温成膜性好、干燥再分散性优异的苯丙乳液,并采用喷雾干燥工艺制得水分散性聚合物乳胶粉。研究了乳化剂补加量、NMA添加对乳液性能的影响,并探讨其作用机理。研究表明:当补加乳化剂量为单体总量的0.33%,NMA用量为单体总量的1%时,可制得综合性能良好苯丙乳液和再分散良好的乳胶粉。以制成的可再分散苯丙乳胶粉配制干粉乳胶涂料,漆膜断面的SEM图表明,再分散乳胶粉对颜填料起到很好的黏接作用,形成结构致密的乳胶漆膜。

A novel styrene-acrylate emulsion with good film formation at low temperature and excellent water redispersity after spray-dry was synthesized by semi-continuous seeded emulsion polymerization and the corresponding redispersible polymer powder was prepared.The main monomers were styrene（St）,butyl acrylate （BA）and methyl methacrylate （MMA）,crosslinking monomers was N-hydroxymethyl acrylamide （NMA）and functional monomer was methylacrylic acid （MAA）.The effect of additional emulsifier,position of NMA transported to and the quantity of NMA on emulsion properties were discussed.The results showed that when the quantity of additional emulsifier and NMA were 0.33% （mass fraction based on the whole monomer,the same below）and 1% respectively and NMA was added in the shell,optimal comprehensive per- formance of the styrene-acrylate emulsion and the polymer powder with good water redispersity was obtained.The redispersible polymer powder was adopted to prepare dry powder latex paint and its SEM photography showed that pigments and fillers were bonded tightly by styrene-acrylate polymer bonded and an uniform paint film was obtained.