Properties / Applications: Desmophen 650A-65 PMA polyester is used as a coreactant for Desmodur N polyisocyanate two-component polyurethane coatings. Finishes based on Desmophen 650A-65 PMA polyester and Desmodur N polyisocyanates are well-suited for uses requiring light stability and weatherability as well as good chemical and abrasion resistance. Suitable substrates include metal, concrete, wood, plastics and paper. Adequate substrate preparation is advisable before using coatings containing Desmophen 650A-65 PMA polyester.The drying times of coatings based on Desmodur N polyisocyanate and Desmophen 650A-65 PMA polyester can be reduced by the addition of catalysts. Suitable catalysts include Desmorapid PP (0.2-0.5% based on solid resin) and dibutyl tin dilaurate (.003-.005% based on solid resin). Such additions reduce the potlife of the formulation and should be evaluated prior to use. The flow of systems containing Desmodur N polyisocyanate and Desmophen 650A-65 PMA polyester can be inmproved by additions of cellulose acetate butyrate resins such as CAB 381-0.1 (0.2% based on resin solids) or certain types of silicone fluids such as Baysilone Paint Additive OL-17 (0.05-0.2% based on resin solids). As with any product, use of Desmophen 650A-65 PMA in a given application must be tested (including but not limited to field testing) in advance by the user to determine suitability.

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