Coating composition comprising a high Mn polyester and a low Mn polyester
AssigneePPG Coatings (Suzhou) Co., Ltd.
InventorsFeng Han, Cunyi Fan, Shimin Wang
Life of this patent
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Abstract
A coating composition including (a) a first polyester material having a number-average molecular weight (Mn) of 500 to 5,500 Daltons, and (b) a second polyester material having a number-average molecular weight (Mn) of 6,000 to 100,00 Daltons. The first polyester material may have a glass transition temperature (Tg) of from 40° C. to 120° C. The coating composition is useful for, among other things, coating food and/or beverage containers, such as an undercoat layer of a two layer coating system that includes an undercoat layer and an overcoat layer.
Claims16
A coating composition comprising;
- (a) a first polyester material having a number-average molecular weight (Mn) of 500 to 5,500 Daltons, and a glass transition temperature (Tg) of from 40° C. to 120° C.;
- and
- (b) a second polyester material having a number-average molecular weight (Mn) of 6,000 to 100,000 Daltons.
A coating composition comprising;
- (a) a first polyester material having a number-average molecular weight (Mn) of 500 to 5,500 Daltons;
- and
- (b) a second polyester material having a number-average molecular weight (Mn) of at least 6,100 Daltons and a glass transition temperature (Tg) of at least about 80° C.,
- wherein the second polyester material (b) comprises the reaction product of
- (i) 1,2-propanediol,
- (ii) terephthalic acid, and
- (iii) a molecular weight increasing agent.
A two layer coating system for a food and/or beverage container comprising an undercoat layer and an overcoat layer, wherein the undercoat layer comprises;
- (a) a first polyester material having a number-average molecular weight (Mn) of 500 to 5,500 Daltons, and a glass transition temperature (Tg) of from 40° C. to 120° C.;
- and
- (b) a second polyester material having a number-average molecular weight (Mn) of 6,000 to 100,000 Daltons.
Dependencies are inferred from the claim text.