以乳化聚合製備之核-殼壓克力感壓膠性質分析

Abstract

本研究以半批次乳化聚合之方式來製備核-殼(core-shell)壓克力感壓膠，並藉由調整甲基丙烯酸甲酯(methyl methacrylate, MMA)及丙烯酸丁酯(butyl acrylate, BA)的比例來製備硬核跟軟殼。我們製備了不同硬核比例之乳液，並探討其轉化率、形貌、乳液顆粒及粒徑分布隨反應時間的變化。透過調整轉化率及降低起始劑用量，成功製備出核-殼乳液。乳液塗佈成黏膠之後，我們將研究其黏膠之玻璃轉移溫度、黏彈性、凝膠與溶膠分子量及感壓膠之物性測試，我們發現隨著硬核的比例提高，黏膠的彈性模數上升，但同時也造成黏著力下降，除了黏膠本身的機械性質之外，其膜的表面型態也會大幅影響黏著性。另外，添加矽烷化合物如3-環氧丙氧丙基三甲氧基矽烷((3-Glycidoxypropyl)trimethoxysilane, GPTMS)及四乙氧基矽烷(tetraethyl orthosilicate, TEOS)也可以大幅提升其初期力及黏著力。

In this study, we synthesized core-shell latexes via a semi-batch polymerization process with different methyl methacrylate/butyl acrylate (MMA/BA) weight ratio on hard-core and soft-shell, respectively. We produced different amount of hard core of the latexes and investigated the conversion, morphology, particle size and particle size distribution of the latexes during different reaction time. The successful core-shell latex was synthesized by adjusting the conversion and lowering the initiator concentration. The glass transition temperature, viscoelasticity, gel and molecular weight of sol and performance of pressure sensitive adhesives (PSA) films cast from these latexes were also discussed. With increased hard-core content in the PSA films, the elastic modulus of PSA films increased but led to a decrease in peeling strength. We also found that not just the mechanical properties of PSA, but also the morphology of the PSA films was related to the peeling strength. Furthermore, the addition of silicone-based components (e.g. (3-glycidoxypropyl)trimethoxysilane (GPTMS) and tetraethyl orthosilicate (TEOS)) to the PSA films showed significantly improvement on the tack and peeling strength.