微胶囊型单组分室温固化压敏胶的制备及性能表征

Preparation and characterization of microencapsulated single-component room temperature curing pressure sensitive adhesive

采用原位聚合法,以三聚氰胺-甲醛(MF)为壁材分别制备了包覆环氧树脂与硫醇的微胶囊,并将两种微胶囊混合制备成单组分环氧压敏胶。当外力使微胶囊囊壁破裂后,由于两种芯材具有良好的互溶性,有利于其释放后的相互扩散和均质化,实现快速均匀固化。对微胶囊的微观形貌、尺寸分布、化学结构、热稳定性进行了表征,并研究了单组分压敏胶的固化放热过程与粘接性能。研究结果表明:所制备的微胶囊都呈规则球形,表面光滑,平均粒径在8~10μm左右,包封率都在70%以上;所制备的微胶囊具备良好的储存稳定性,室温下可长期储存而不发生质变,升温到150℃时皆能高效适用;将活性组分进行微胶囊化包覆不会破坏芯材的反应活性,且该胶粘剂在室温甚至低温下都有较好的固化效果;将两种微胶囊混合制备成单组分胶粘剂,并对其进行粘接强度测试,结果表明该微胶囊型单组分室温固化压敏胶十分具有发展潜力。

Microcapsules coated with epoxy resin and thiol were prepared respectively by in situ polymerization method with melamine-formaldehyde(MF)as the wall material,and single-component epoxy pressure sensitive adhesive was then prepared by mixing two kinds of microcapsules.When the microcapsule walls were ruptured by external force,two kinds of core materials had good mutual solubility,which facilitated their mutual diffusion and homogenization after release to achieve rapid and uniform solidification.The microscopic morphology,size distribution,chemical structure and thermal stability of the microcapsules were characterized,and the curing exothermic process and bonding properties of single-component pressure sensitive adhesive were studied.The research results showed that the prepared microcapsules were all spherical in shape,with a smooth surface and an average particle size of about 8-10μm,and the encapsulation rate was above 70%.The prepared microcapsules had good storage stability and could be stored for a long time at room temperature without quality change.They could be applied efficiently even when heated to 150℃.Microencapsulation of the active components would not damage the reactivity of the core material,and the adhesive had good curing effect at room temperature or even low temperature.Two kinds of microcapsules were mixed to prepare single-component adhesive,and the bonding strength was tested,the results showed that this microencapsulated single-component room temperature curing pressure sensitive adhesive had great potential for development.