Solid mixture of blocked polyisocyanate and hydroxy-polyacrylate useful in powder lacquer

摘要

Pulverizable mixture, which is solid below 40 deg C and suitable as powder lacquer or binder for clear or pigmented powder lacquers, is based on (a) an isocyanate component with blocked isocyanate (NCO) groups, (b) a polyhydroxyl compounds and (c) optionally usual ancillaries and additives. The novel features are that (1) component (a) is a completely or partly blocked aliphatic diisocyanate, chain extended with aliphatic and/or cycloaliphatic diamines, of formula (I); in which R = -CH2-CH(CH3)-(CH2)3-, -CH2-CH(C2H5)-(CH2)2-, -(CH2)4-, -CH2-C(CH3)2-CH2-CH(CH3)-CH2-CH2-, -CH2-CH(CH3)-CH2-C(CH3)2-CH2-CH2- or -(CH2)4-CH(CH3)-(CH2)4-; R<1> = (cyclo)alkylene with 2-16C atoms; B = a 2-oxo-azepin-1-yl, CH3C(C2H5)=N-O-, Ph-C(CH3)=N-O-, 2,2,6,6-tetramethylpyridin-6-diylnitrosoyl, 1,2,4-triazin-1-yl or 3,5-dimethylpyrazol-1-yl; n = 1-3; x = 0-0.5; (2) component (b) is a polyacrylate containing OH groups; and (3) (a) is used in an amount giving 0. 4-1.2, preferably 0.7-1.1, especially 1 NCO equivalent per hydroxyl (OH) equivalent in (b). Also claimed is a cured coating from this mixture.