US 12,435,238 B2
Thermosetting coating composition with improved scratch resistance
Jianhui Zhou, Kingsport, TN (US); and Stacey James Marsh, Church Hill, TN (US)
Assigned to Eastman Chemical Company, Kingsport, TN (US)
Appl. No. 17/250,989
Filed by Eastman Chemical Company, Kingsport, TN (US)
PCT Filed Oct. 7, 2019, PCT No. PCT/US2019/054915
§ 371(c)(1), (2) Date Apr. 8, 2021,
PCT Pub. No. WO2020/076661, PCT Pub. Date Apr. 16, 2020.
Claims priority of provisional application 62/744,171, filed on Oct. 11, 2018.
Prior Publication US 2021/0348016 A1, Nov. 11, 2021
This patent is subject to a terminal disclaimer.
Int. Cl. C09D 167/02 (2006.01); C08G 63/199 (2006.01); C09D 7/20 (2018.01)
CPC C09D 167/02 (2013.01) [C08G 63/199 (2013.01); C09D 7/20 (2018.01)] 16 Claims
 
1. 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.