Binder systems for waterborne two-pack products for car refinishes application

摘要

Waterborne (WB) products are of growing importance in the car refinishes market. Especially WB basecoats are gaining increased market share during the last couple of years. The introduction of WB two-pack primers, fillers, clearcoats and single stage topcoats is hampered, however due to the lack of suited binder systems. In this paper, new approaches will be presented for two-pack binder systems. A number of topics will be discussed in more detail: the design of the binders, the involved chemistry, the incorporation of stabilizing and reactive groups, the functionality and miscibility of the hardener. Based on these variables, the most important properties have been studied: film formation, reactivity, potlife and paint properties like hardness, appearance and water and solvent resistance. During the investigation, model studies have also been applied. It is shown that some binder systems offer very attractive features in which a number of properties can be tuned, e.g. amine-functional emulsions combined with acetoacetate-functional hardeners result in an excellent level of properties suited for primer/filler application. These binder systems have been used as the starting points for product development that resulted in new prototypes of low VOC WB products with a very attractive overall performance. (C) 2003 Elsevier B.V. All rights reserved. [References: 11]