NOVEL SEMI-CRYSTALLINE POLYESTERS, BLENDS THEREOF WITH AMORPHOUS POLYESTERS AND POWDER COATING COMPOSITIONS BASED ON SUCH BLENDS

• Main Authors: JONES, GLENN C, CHANG, YEONG-HO
• Format: Patent
• Language: English; French
• Published: 28.11.1995
• Edition: 6
• Subjects: ADHESIVES; CHEMICAL PAINT OR INK REMOVERS; CHEMISTRY; COATING COMPOSITIONS, e.g. PAINTS, VARNISHES ORLACQUERS; COMPOSITIONS BASED THEREON; COMPOSITIONS OF MACROMOLECULAR COMPOUNDS; CORRECTING FLUIDS; DYES; FILLING PASTES; INKS; MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONSONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS; METALLURGY; MISCELLANEOUS APPLICATIONS OF MATERIALS; MISCELLANEOUS COMPOSITIONS; NATURAL RESINS; ORGANIC MACROMOLECULAR COMPOUNDS; PAINTS; PASTES OR SOLIDS FOR COLOURING OR PRINTING; POLISHES; THEIR PREPARATION OR CHEMICAL WORKING-UP; USE OF MATERIALS THEREFOR; WOODSTAINS

Disclosed are thermosetting, powder coating compositions comprised of blends of certain amorphous polyesters and semicrystalline polyesters in combination with a blocked polyisocyanate which, when applied to a substrate and heated, provide crosslinked coatings having a combination of desirable properties including good gloss, impact strength and flexibility. The semi-crys-talline polyesters have a Tg of less than 50.degree.C, a hydroxyl number of 20 to 100, an inherent viscosity of 0.1 to 0.5, a melting range of 70 to 150.degree.C, a number average molecular weight of 1500 to 10,000 and a heat of fusion (second heating cycle of differential scanning calorimetry) of greater than 5 cal/g-.degree.C and are comprised of: (i) diacid residues comprised of (a) 80 to 98 mole percent terephthalic acid and (b) 2 to 20 mole percent of 1,4-cyclohexanedicarboxylic acid residues, 1,3-cyclohexanedicarboxylic acid residues, adipic acid residues or a mixture thereof; and (ii) glycol residues comprised of at least 50 mole percent of residues having the formula -O-(CH2)n-O- wherein n is 4 to 12.