POLYURETHANE POWDER COATINGS - FROM HIGH GLOSS TO DEAD MATTE

摘要

Amorphous polyesters are the typical reaction partners for polyisocyanate crosslinkers, a combination that results in high gloss powder coatings. Achieving a semi-matte or dead-matte finish is much more complicated, and despite numerous patents and articles, no single system has been widely accepted. Basic requirements such as ease of handling, reproducibility, good mechanical properties, and cost efficiency are not sufficiently satisfied with traditional methods. A new method to produce to matte polyurethane powder coatings was found to provide coatings with adjustable gloss and very good flow. Furthermore, good mechanical properties are obtainable, even with super-durable polyesters. This method employs combinations of amorphous and crystalline polyesters, with polyureas as organic fillers. This paper will review formulation and performance properties of matte polyurethane coatings using these materials.