Development Of Ambient Crosslinking Acrylic Latex Coatings

Crosslinking is an important means to improve the film performance such as water-resistence, solvent-resistence, pollution-resistence and mechanical intensity of coatings. No heat being needed in using, ambient crosslinking not only economizes the energy but also facilitates the application of coatings. Therefore, importance has been attached to developing ambient crosslinking coatings. Ambient crosslinking acrylic latex coatings is of excellent light-protection, color-protection, water-resistence, pollution-resistence, weather-resistence as well as good hardness. Acrylic latex coatings can be cured at room temperature by dehydration reaction between a carbonyl-containing acrylic copolymer having an active aldo group or keto group and a hydrazine derivative having at least two hydrazino groups per molecule under the acid catalysis condition. It is a recommendable method reported by foreign scholars. There has been less research about this ambient crosslinking acrylic latex coatings at home and the systematical report has not been seen in domestic literatures at present.Above said carbonyl-containing acrylic copolymer is generally obtained by copolymerizing a monomer mixture consisting of a carbonyl-containing monomer-diacetone acrylamide (DAAM) and- acrylate monomers. DAAM is usually prepared by reaction acetone with acrylonitrile and purified by distillation under vacuum. However, it is very difficult to avoid polymerizing of DAAM during purification because of its high polymerization reactivity and higher boiling point. In this paper, the synthesis and purification of DAAM were studied using acetone and acrylonitrile as starting materials and a convenient process consisted of...