涂布过程对涂层结构及油墨吸收性影响的研究

Influence of Coating Process Variables on the Structure and Ink Absorbency of the Coating Layer

考察了涂布加工过程对涂层结构(包括胶黏剂分布和孔隙率)和油墨吸收性的影响。结果发现,涂层的油墨吸收性能不但依赖于孔隙结构而且依赖于涂层表面的胶黏剂含量。在室温干燥时,涂层表面结构较为开放,涂层的油墨吸收性主要取决于涂层的孔隙率。在高温干燥时,胶黏剂更容易迁移到涂层表面,在表面形成封闭的胶乳膜,此时涂层的油墨吸收性主要取决于涂层表面的胶黏剂含量。

Ink absorption is one of the major factors that affect printability of coated papers and boards.Conventional wisdom considers that ink absorbency is mainly affected by porosity or void fraction of the coating layer,which is in turn affected by binder content in the coating formulation.On the other hand,it has been found in this work that ink absorption depends not only on porosity,but also on drying conditions of the coatings.When the drying is under room conditions,ink absorption increases with increasing coating porosity,as observed in the literature.However,when the drying is at higher temperature with hot-air,ink absorbency increases with increasing solid content of the coating colors,or with decreasing coating porosity.This phenomenon is attributed to more pronounced latex migration under faster drying,leading to the formation of a more closed coating surface.