液态光学胶的固化收缩率的研究

Studies on Curing Shrinkage of Liquid Optical Clear Adhesive

紫外光固化的液态光学胶固化过程中出现的体积收缩现象,严重影响其黏接强度和产品外观.系统研究了液态光学胶预聚物的种类、活性稀释剂的种类和用量、光引发剂的用量、光固化的类型等诸多因素对固化收缩率的影响.研究发现,以聚乙二醇二丙烯酸酯作为预聚物可明显降低固化收缩率.当添加的活性稀释剂官能度相同时,胶黏剂的固化收缩率随活性稀释剂相对分子质量的增加而减小;当活性稀释剂相对分子质量相近时,官能度增加,固化收缩率随之增大.而光引发剂的用量则对固化收缩率无明显影响.阳离子型胶黏剂的固化收缩率比自由基型的小,但硬度和黏接强度较低;而混杂型的固化收缩率则介于二者之间.

The volume shrinkage during UV curing of liquid optical clear adhesives （LOCA） had a serious effect on the adhesive strength and appearance of the product.In this paper,the effect of different factors,including types of active diluents,amounts of active diluents and photo initiators,and UV curing types,on the volume shrinkage for LOCA was systematically investigated.Based on the experiment,polyethylene glycol diacrylate as the prepolymer could significantly reduce the shrinkage.With the same functionality of the added active diluents,the shrinkage decreased when the molecular weights of the active diluents increased.When the molecular weights of active diluents were similar,the shrinkage increased with the increase of the functionality.The amount of photo-initiators had no significant effect on shrinkage.The shrinkage of cationic adhesives was smaller than that of radical adhesives,but the hardness and adhesion strength were relatively lower.The shrinkage of hybrid adhesives was in between in general.