文档介绍：INTRODUCTION TO POLYMER SCIENCE
Coating and adhesive 涂料与粘合剂
四川大学化学学院
Substrate 2
Foundation of Coating and Adhesive
粘接(adhesion)
Adhesion is the tendency of certain dissimilar molecules to cling together due to attractive forces. In contrast, cohesion takes place between similar molecules.
Mechanical adhesion: Adhesive materials fill the voids or pores of the surfaces and hold surfaces together by interlocking
Chemical adhesion: Two materials may form pound at the join.
Dispersive adhesion: also known as physisorption, two materials are held together by van der Waals forces.
Electrostatic adhesion: Some conducting materials may pass electrons to form a difference in electrical charge at the join.
Diffusive adhesion: Some materials may merge at the joint by diffusion.
Substrate
Substrate 1
Adhesive
Coating
Function of the coating
Decoration
制品鲜艳美观的涂装可使物品显得更加美观、起到美化环境和美化生活的作用。
Function of the coating
Protection
物质暴露在大气中,受湿气、氧气、CO2、CO、NH3、NO2、NO等酸碱气体和溶剂的侵蚀,从而造成金属锈蚀、木材腐朽、水泥风化等破坏现象。
Function of the coating
Remark
涂覆绘制在制品表面,通过图案、色彩等表示各种特殊信息。
Principle of the coating
涂料在使用前通常是具有反应活性官能团的液态低分子或线形高分子化合物(溶液或熔融物)。
将具有流动性的涂料涂布在所保护物体表面。
通过涂料活性官能团的反应进行聚合和交联;也可以是溶剂挥发后聚合物析出或熔融聚合物冷却后在物体表面形成一层薄膜。
最后通过低沸点溶剂的流延和挥发或熔融聚合物的冷却就形成了一层均匀、致密和美观的涂料保护层。
History of the coating
天然树脂(natural resin)阶段
即主要以天然油脂、大漆、虫胶等天然树脂或改性的天然树脂为原料制成的溶剂性涂料和天然树脂涂料。
天然树脂的特点是原料易得,制备工艺简单,但涂料的性能和用途都很有限。
用于涂料的天然树脂俗称大漆,是我国著名特产,又有“国漆”之称。从漆树上采割下来的汁液称为毛生漆或原桶漆,用白布滤去杂质称为生漆,即可直接涂饰家具及其他制品。也可将生漆进行精制或改性处理制得具有多种性能的天然漆。
History of the coating
Chinese Lacquer
:漆酚40%~70%、漆酶含氮物10%、树胶汁约为10%、水分15%-40%。
Natural resin using for coating
pitch
beeswax
gum arabic