Polyesters and coatings containing the same

摘要

Disclosed is a polyester prepared from a mixture of reactants including: a) an aromatic monoacid, where the aromatic monoacid includes from 25 to 60 weight % based on the total weight of reactants; b) a polyacid, where the polyacid includes less than 90 mole % isophthalic acid; and c) a polyol having at least 3 hydroxyl groups. The mixture of reactants is substantially free of a non-aromatic monoacid, and said polyester has a dynamic viscosity of greater than 15,000 centipoise at 40° C. as measured by a Physica MCR 301 rheometer with 25 mm parallel plate and 0.1 mm gap as a function of increasing shear rate (0.1 to 10 s−1), and an acid value of less than 15 mg KOH/g. The polyacid can also be an aliphatic polyacid. Coatings comprising the same and substrates coated at least in part with such coatings are also disclosed.

主权项

1. A polyester prepared from a mixture of reactants comprising:
a) an aromatic monoacid, wherein the aromatic monoacid comprises from 25 to 60 weight % based on the total weight of reactants; b) a polyacid, wherein the polyacid comprises less than 90 mole % isophthalic acid; and c) a polyol comprising at least 3 hydroxyl groups,
wherein the mixture of reactants contain less than 1000 parts per million of a non-aromatic monoacid, and said polyester has a dynamic viscosity of greater than 15,000 centipoise at 40° C. as measured by a Physica MCR 301 rheometer with 25 mm parallel plate and 0.1 mm gap as a function of increasing shear rate (0.1 to 10 s−1), an acid value of less than 15 mg KOH/g, and a glass transition temperature of less than 0° C.