不同固含量涂料的固化机理研究

Investigation of Consolidation Mechanism of Model Clay Coatings with Different Solid Contents

基于Lepoutre经典固化机理,将Croll胶乳成膜机理引入到涂层固化的研究中。结合表面光泽度和蒸发速率两种固化过程表征方法,测定不同固含量涂层随固化时间的变化,并利用已提出的滤饼层固化机理描述涂层固化过程。使用拍摄测定全程的方法采集数据,从而确保数据与固化时间同步。利用线性相关系数的概念获得蒸发速率曲线上的临界时间及其速率。结果表明,蒸发速率恒速阶段的临界点位于涂层第一临界浓度(FCC)与第二临界浓度(SCC)之间,由滤饼层理论可知此临界点的固含量即为胶乳融合变形浓度(LCC)。FCC、SCC和LCC随涂料初始固含量的增加而增加,但其临界时间随之缩短。涂层固化过程可划分为3个阶段,并可以被新的固化机理合理地解释。初步证明了涂层表面滤饼层形成的过程,加深了对涂层结构形成和固化机理的理解。

Based on Lepoutre＇s classic coating consolidation theory,Croll＇s latex film mechanism was introduced into consolidation study of coating layer.The drying processes of model clay coatings with different solid contents were monitored to investigate consolidation mechanism.Both gloss development and evaporation rate of the coating layer were measured to characterize consolidation process.A new consolidation mechanism of filter cake was used to describe consolidation process.Moreover,all the data were recorded by camera so as to improve synchrony between time and data and minimize systematical error.The results showed that evaporation rate at constant phase is equal approximately to that of distilled water,and the constant phase ends at LCC（latex coalescence concentration）.The solid contents at all the critical points increase with increasing initial solid content of model coatings,but the time to reach critical point is shortened.The evaporation process of model coatings can be successfully described by a new consolidation mechanism.This work brings a powerful confirmation to filter cake formation,contributing to a further understanding of coating structure formation and mechanism.It could be used in industrial applications if it is further confirmed.