METHOD OF PREPARING POWDER COATING COMPOSITIONS INVOLVING POLYMER WASTE PROCESSING STAGE Russian patent published in 2003 - IPC

FIELD: polymer materials. SUBSTANCE: invention relates to powder coating compositions based on solid epoxide resins and carboxylcontaining polyester resins prepared using polyethylene terephthalate waste, which are used for corrosion-protective and ornamental coatings for metals and metalware. Composition is prepared by alkoholysis of secondary polyethylene terephthalate (household storage containers) with polyatomic alcohol and esterification of resulting hydroxyl-containing polyester with phthalic anhydride distillation waste at molar ratio of phthalic anhydride to hydroxylcontaining polyester (0.31-0.35):1 to give solid carboxyl-containing polyester resin. The latter (30-56%) is then mixed with solid 4,4'-isopropylidene epoxide resin (28-54%) in presence of zinc oxide (3-5%) as hardening catalyst, vinyline (1-2%) as flow property regulator, pigment (1.5-9%), and ferroalloy production waste (6- 9%) as filler, said ferroalloy production waste being more particularly ferrovanadium slime or silicate dust of ferrosilicium. Resulting mixture is homogenized and disintegrated. EFFECT: extended source of starting materials, utilized household and industrial wastes, reduced production expenses, and improved physicochemical characteristics of coatings. 3 cl, 5 tbl