Abstract:
A pulverulent coating composition adapted to be applied to a substrate by spraying as a powder is prepared by a process which comprises reacting an organic polyisocyanate containing a uretdione group with an organic compound containing groups which contain reactive hydrogen atoms determinable by the Zerewitinoff method wherein the functionality of the reactants and the proportions thereof are chosen to provide an average functionality between about 2.05 and 10, the ratio of reactive hydrogen groups to -NCO groups is between about 1.07 to 1 and about 2.5 to 1 and the amount of polyisocyanate containing uretdione groups is sufficient to provide from about 0.6 percent to about 25 percent by weight uretdione groups.
Abstract:
Copolymer having an average molecular weight of 500 to 10,000, a glass transition temperature of 40* to 70*C and an acid number of 55 to 120 mg of KOH/g of copolymer, said copolymer being the product of free radical copolymerization of a monomer mixture of I. 0 to 55 mol % of styrene, Alpha -methylstyrene, methylmethacrylate or mixtures thereof; II. 10 to 25 mol % of acrylic acid, methacrylic acid or mixtures thereof; III. 0 to 70 mol % of at least one ester of methacrylic acid containing 2 to 18 carbon atoms in the alcohol component and IV. 20 to 50 mol % of at least one ester of acrylic acid containing 1 to 18 carbon atoms in the alcohol component, AND PROCESS OF PRODUCING SAID COPOLYMER BY CONTINUOUSLY POLYMERIZING SAID MONOMER MIXTURE IN A CONTINUOUSLY FED PROCESS UNDER STEADY STATE AND PERFECTLY AGITATED CONDITIONS TO A CONVERSION OF 35 TO 60 MOL % AND THEN POLYMERIZING RESULTING POLYMERIZATION REACTION MIXTURE TO A CONVERSION OF AT LEAST 94 MOL % UNDER NON-STEADY STATE CONDITIONS WHICH PREVENT BACK MIXING OF THE POLYMER PRODUCED IN SAID SECOND POLYMERIZATION STEP WITH POLYMERIZATION REACTION MIXTURE FROM SAID FIRST POLYMERIZATION REACTION STEP IN A TUBULAR PLUG FLOW REACTOR UNDER NON-STEADY STATE CONDITIONS.
Abstract:
Copolymers of 23 to 92% by weight of methyl methacrylate, 5-62% by weight of an acrylic acid ester containing from 1 to 12 carbon atoms in the ester portion or a methacrylic acid ester containing from 2 to 12 carbon atoms in the ester portion and 3 to 15% by weight of unsaturated copolymerizable carboxylic acids are homogeneously mixed with triglycidyl isocyanurate, cellulose acetobutyrates and optionally with pigments and levelling agents. The mixture may be applied by electrostatic powder-spraying or other powder coating processes to suitable surfaces and cured at temperatures of about 130* to 220*C. The backed films of the mixture show outstanding adherence to the substrate and hardness coupled with elasticity, high gloss and weather resistance.
Abstract:
Copolymers of (meth)acrylates and Alpha , Beta monoolefinically unsaturated carboxylic acid having three to five carbon atoms are used as additives for improving levelling, glass and reactivity in powder lacquers. Said powder lacquers contain polymerized units of at least 35% by weight of styrene and (meth)acrylate and 5 to 30% by weight of at least one monomer containing a hydroxyl, carboxyl, glycidyl, N-methylol or Nmethylol ether group. The powder lacquer mixture contains 0.1 to 5% by weight of the additive.
Abstract:
LACQUER MIXTURES CONTAINING AT LEAST ONE HYDROXYL FREE POLYACRYLATE RESIN HAVING CARBONAMIDE GROUPS AND MOLECULAR WEIGHT ABOVE 600 AND AT LEAST ONE POLY-B-ALKOXYMETHYLURETHANE CROSS-LINKING AGENT.
Abstract:
Coating powders comprising mixtures of poly-(5,6-dihydro-4H-1,3oxazines) and copolymers of 25-70% by weight of styrenes and/or (meth)acrylonitrile, 30-65% by weight of (meth)acrylates (the methyl methacrylate content is not greater than 25%) and 5-20% by weight of Alpha , Beta -monoolefinic unsaturated carboxylic acid having 3-5 carbon atoms and optionally pigments or levelling agents. The powders are suitable for use in the electrostatic powder spraying process.