Decomposable Crosslinking Paint: Waste Minimization

By Yasuharu Nakayama

A paint film crosslinked by a reaction between a carbonyl group and a hydrazide group could be easily decomposed by dipping it in a solution containing water, solvents, and acids. The method was studied to minimize the waste produced by the elimination of the decomposable paint film. This was performed in two steps: a dipping in aqueous solution containing solvents and acids, and a successive wash with solvents.

Decomposition of the crosslinking bonds and the elution of the decomposed free crosslinker took place in the first dipping process, and the elimination of the decomposed resins in the second washing pro-cess. The aqueous solution could be used for a long time without contamination by the decomposed resins, and the decomposed resin could easily be recovered from the resin solution containing no other contaminants.