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US 12,435,238 B2Granted
Thermosetting coating composition with improved scratch resistance
AssigneeEastman Chemical Company
InventorsJianhui Zhou, Stacey James Marsh
Life of this patent
Estimating the term…
Abstract
This invention relates to aliphatic, carbamate-functional polyester resins for use in coatings. More particularly this invention relates to aliphatic, carbamate-functional polyester resins containing 2,2,4,4-tetramethyl-1,3-cyclobutanediol (TMCD) that exhibit improved scratch resistance and acid etch resistance when formulated into 2K automotive clearcoats. These carbamate-functional polyesters can be used as the sole resin in the clearcoat binder or in combination with other carbamate-functional acrylic resins and/or hydroxyl-functional acrylic and polyester resins.
Claims16
A coating composition comprising:
- A. 40 to 70 weight percent, based on the total weight of (A) and (C), of at least one curable, aliphatic polyester, comprising residues of:
- i. a hydroxyl component, said hydroxyl component comprising the residues of:
- a. from 31 to 45 mole %, based on the total moles of (a) and (b), of 2,2,4,4-tetraalkylcyclobutane-1,3-diol;
- and
- b. from 55 to 69 mole %, based on the total moles of (a) and (b), of other diols and polyols;
- ii. a diacid component, said diacid component comprising the residues of at least one aliphatic dicarboxylic acid comprising:
- C. 95 to 100 mole %, based on the total moles of the diacids (c) and (d), of an alicyclic dicarboxylic acid;
- and
- d. 0 to 5 mole %, based on the total moles of the diacids (c) and (d), of an acyclic aliphatic diacid;
- wherein the at least one curable, aliphatic polyester has a hydroxyl number of 255 to 350 mgKOH/g of polyester, a Tg of 16 to 45 degree C., and an acid number of 0 to 15 mgKOH/g;
- B. from 30 to 60 weight percent, based on the total weight of (A) and (B), of a crosslinker;
- C. from 35 to 60 weight percent, based on the total weight of the coating composition, of a solvent other than water;
- wherein when said coating composition is cured, a cured coating is formed having:
- (1) a tree sap resistance of greater than 70 degree C. as determined in accordance with the temperature-gradient oven method according to DIN EN ISO 2812-5:2007-05;
- (2) a gloss retention, based on a simulated carwash test using a sheen wet abrasion scrub tester machine with brush ID 42472 and tested according to DIN EN ISO 20566, of greater than 75%;
- and (3) a fracture resistance greater than 20 mN when tested using a nano scratch tester with 2 μm indenter per ASTM D7187-15.
13 more elements
A coating composition consisting essentially of:
- I. a polyester component comprising:
- A. 40 to 70 weight percent, based on the total weight of (A) and (C), of at least one curable, aliphatic polyester, comprising residues of:
- i. a hydroxyl component, said hydroxyl component comprising the residues of:
- a. from 31 to 45 mole %, based on the total moles of (a) and (b), of 2,2,4,4-tetraalkylcyclobutane-1,3-diol;
- and
- b. from 55 to 69 mole %, based on the total moles of (a) and (b), of other diols and polyols;
- ii. a diacid component, said diacid component comprising the residues of at least one aliphatic dicarboxylic acid comprising:
- C. 95 to 100 mole %, based on the total moles of the diacids (c) and (d), of an alicyclic dicarboxylic acid;
- d. and 0 to 5 mole %, based on the total moles of the diacids (c) and (d), of an acyclic aliphatic diacid;
- wherein the at least one curable, aliphatic polyester has a hydroxyl number of 120 to 350 mgKOH/g of polyester, a Tg of 16 to 45 degree C., and an acid number of 0 to 15 mgKOH/g;
- B. from 30 to 60 weight percent, based on the total weight of (A) and (B), of a crosslinker comprising an isocyanate or melamine crosslinker;
- C. from 35 to 60 weight percent, based on the total weight of the coating composition, of a solvent other than water;
- and
- II. a hydroxyl functional thermosetting acrylic resin component
- wherein when said coating composition is cured, a cured coating is formed having:
- (1) a tree sap resistance of greater than 70 degree C. as determined in accordance with the temperature-gradient oven method according to DIN EN ISO 2812-5:2007-05;
- (2) a gloss retention, based on a simulated carwash test using a sheen wet abrasion scrub tester machine with brush ID 42472 and tested according to DIN EN ISO 20566, of greater than 75%;
- and (3) a fracture resistance greater than 20 mN when tested using a nano scratch tester with 2 μm indenter per ASTM D7187-15.
15 more elements
A coating composition comprising:
- I. a polyester component comprising:
- A. 40 to 70 weight percent, based on the total weight of (A) and (C), of at least one curable, aliphatic polyester, comprising residues of:
- i. a hydroxyl component, said hydroxyl component comprising the residues of:
- a. from 31 to 45 mole %, based on the total moles of (a) and (b), of 2,2,4,4-tetramethyl-1,3-cyclobutanediol;
- and
- b. from 55 to 69 mole %, based on the total moles of (a) and (b), of trimethylolpropane;
- ii. a diacid component consisting essentially of the residues of hexahydrophthalic anhydride;
- and
- wherein the curable polyester has a hydroxyl number of 255 to 350 mgKOH/g of polyester, and an acid number of 0 to 15 mgKOH/g;
- B. from 30 to 60 weight percent, based on the total weight of (A) and (B), of a crosslinker comprising an isocyanate;
- C. from 35 to 60 weight percent, based on the total weight of the coating composition, of a solvent other than water;
- and
- II. a hydroxyl functional thermosetting acrylic resin component;
- wherein when said coating composition is cured, a cured coating is formed having:
- (1) a tree sap resistance of greater than 70 degree C. as determined in accordance with the temperature-gradient oven method according to DIN EN ISO 2812-5:2007-05;
- (2) a gloss retention, based on a simulated carwash test using a sheen wet abrasion scrub tester machine with brush ID 42472 and tested according to DIN EN ISO 20566, of greater than 75%;
- and (3) a fracture resistance greater than 20 mN when tested using a nano scratch tester with 2 μm indenter per ASTM D7187-15.
14 more elements
Dependencies are inferred from the claim text.