Thermosetting acryl powder coating
OwnerLuc Moens, Marc Van Muylder +2inventors
InventorsLuc Moens, Marc Van Muylder, Nele Knoops, Daniel Maetens
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Abstract
The present invention relates to a composition for thermosetting powder coating having excellent low temperature curability and good storage stability, being capable of giving a coating with good appearance, flexibility and solvent resistance. The powder coating composition comprises a blend of two different glycidyl group containing acrylic copolymers and a polycarboxylic acid curing agent.
Claims13
Composition for thermosetting powder coating comprising a co-reactable blend of two glycidyl group containing acrylic copolymers and a carboxylic group containing compound, wherein:
- (a) a first glycidyl group containing acrylic copolymer (a) has a high glass transition temperature in the range of from +45 to +100° C. and a number average molecular weight in the range of from 2500 to 5000
- (b) a second glycidyl group containing acrylic copolymer (b) has a low glass transition temperature in the range of from −50 to +30° C. and a number average molecular weight in the range of from 5000 to 20000,
- (c) the carboxylic group containing compound is selected from the group comprising:
- 1) a carboxylic group containing polyester, the acrylic copolymer (a) being present in 60-95 parts by weight and the acrylic copolymer (b) being present in 5-40 parts by weight, calculated on the total weight of (a) and (b);
- 2) a polycarboxylic acid, the acrylic copolymer (a) being present in 60-80 parts by weight and the the acrylic copolymer (b) being present in 20-40 parts by weight, calculated on the total weight of (a) and (b);
Composition according to any of the proceeding claims, wherein the acrylic copolymers (a) and (b) comprise
- 1-95 mole percent of one or more monomers selected from methyl(meth)acrylate, ethyl(meth)acrylate, propyl(meth)acrylate, n-butyl(meth)acrylate, isobutyl(meth)acrylate, tert.butyl(meth)acrylate, 2-ethylhexyl(meth)acrylate, stearyl(meth)acrylate, tridecyl(meth)acrylate, cyclohexyl(meth)acrylate, n-hexyl(meth)acrylate, benzyl(meth)acrylate, phenyl(meth)acrylate, isobornyl(meth)acrylate, nonyl(meth)acrylate, hydroxyethyl(meth)acrylate, hydroxypropyl(meth)acrylate, hydroxybutyl(meth)acrylate, 1,4-butandiol mono(meth)acrylate, the esters of methacrylic acid, maleic acid, maleic anhydride, itaconic acid, dimethylaminoethyl(meth)acrylate, diethylaminoethyl(meth)acrylate, styrene, α-methylstyrene, vinyltoluene, (meth)acrylonitrile, vinylacetate, vinylpropionate, acrylamide, methacrylamide, methylol(meth)acrylamide, vinylchloride, ethylene, propylene, C4-20 olefins and α-oleflns and 5-99 mole percent of one or glycidyl group containing monomers selected from glycidylacrylate, glycidylmethacrylate, methylglycidylmethacrylate, methylglycidylacrylate, 3,4-epoxycyclohexylmethyl(meth)acrylate, 1,2-ethyleneglycol glycidylether(meth)acrylate, 1,3-propyleneglycolglycidylether(meth)acrylate, 1,4-butyleneglycolglycidylether(meth)acrylate. 1,6-hexanediolglycidylether(meth)acrylate, 1,3-(2-ethyl-2-butyl)-propanediolglycidylether(meth)acrylate and acrylic glycidylethers.
Composition according to any of the preceding claims, wherein the polycarboxylic acid constituent is selected from
- an aliphatic polycarboxylic acid such as adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, undecanedioic acid, tridecanedioic acid, tetradecanedioic acid, pentadecanedioic acid, hexadecanedioic acid, octadecancedioic acid, eicosanedioic acid, 1,10-dodecanedioic acid, docosanedioic acid or tetracosanedioic acid,
- a cycloaliphatic polycarboxylic acid such as hexahydrophthalic acid, tetrahydrophthalic acid, 1,2-cyclohexanedicarboxylic acid, 1,3-cyclohexanedicarboxylic acid or 1,4-cyclohexanedicarboxylic acid, or
- an aromatic polycarboxylic acid such as isophthalic acid, phthalic acid or trimellitic acid.
Dependencies are inferred from the claim text.