Quick-drying, energy-elastic, scratch-resistant and stable coating compounds

Patent metadata

Field	Value
Publication number	US-10604675-B2
Application number	US-201515125338-A
Country	US
Kind code	B2
Filing date	Mar 2, 2015
Priority date	Mar 12, 2014
Publication date	Mar 31, 2020
Grant date	Mar 31, 2020

Abstract

The present invention relates to fast-drying, hard-elastic, scratch-resistant, and robust two-component polyurethane coating compositions, to their use, and to coating methods. Synthesis components in the coating compositions comprise polyisocyanate, hydroxyl-containing poly(meth)acrylate polyol, and certain branched polyester polyols, obtainable by polycondensation of hexahydrophthalic anhydride, trimethylolpropane, and optionally further components.

First claim

The invention claimed is:

1. A two-component polyurethane coating composition for solventborne systems, comprising as synthesis components
(A) at least one polyisocyanate obtainable by reacting at least one monomeric isocyanate selected from the group consisting of 1,6-hexamethylene diisocyanate, 1,3-bis(isocyanatomethyl)cyclohexane, isophorone diisocyanate and 4,4′- or 2,4′-di(isocyanato- cyclohexyl)methane,
(B) at least one hydroxyl-containing poly(meth)acrylate polyol having an OH number of from 80 to 160 mg KOH/g,
(C) at least one branched polyester polyol obtainable by polycondensing
hexahydrophthalic anhydride,
trimethylolpropane,
optionally at least one further diacid or triacid or derivatives thereof, and
optionally at least one further diol or triol,
wherein
the acid number of the polyester polyol is 50 mg KOH/g to 110 mg KOH/g, based on solids,
the acid groups and hydroxyl groups of the polyester polyol are used in a molar mixing ratio of acid groups to hydroxyl groups of 1:1 to 1:1.95,
less than 20% of free diacid and/or free triacid is used as a reactant in the preparation of the polyester polyol stoichiometrically, based on hexahydrophthalic anhydride, and
less than 20% of tetraalcohol is used in the polyesterol stochiometrically, based on hexahydrophthalic anhydride, and

(D) at least one organic solvent
wherein the stoichiometry of isocyanate groups in (A) to isocyanate-reactive groups in (B) and (C) is from 0.7:1 to 1.3:1 and the weight ratio of poly(meth)acrylate polyol (B) component to the branched polyester polyol (C) component is from 2.3:1 to 20:1.

2. The coating composition according to claim 1 , wherein the poly(meth)acrylate polyol (B) has a molecular weight M n (number average) of 500 to 50 000 D.

3. The coating composition according to claim 1 , wherein the poly(meth)acrylate polyol (B) has an acid number of less than 30 mg KOH/g.

4. The coating composition according to claim 1 , wherein the polyester polyol (C) has a total of acid number and OH number according to DIN 53240, Part 2 of up to 600 mg KOH/g.

5. The coating composition according to claim 1 , wherein the polyester polyol (C) is prepared from hexahydrophthalic anhydride and trimethylolpropane in a molar mixing ratio of acid groups to hydroxyl groups of 1:1.1 to 1:1.6.

6. The coating composition according to claim 1 , wherein the polyester polyol (C) is prepared from hexahydrophthalic anhydride, trimethylolpropane, and neopentyl glycol in a molar mixing ratio of the acid groups to the hydroxyl groups of 1:1.1 to 1:1.6 and a molar mixing ratio of the hydroxyl groups of trimethylolpropane to the hydroxyl groups of neopentyl glycol of greater than 1:1; or wherein the polyester polyol (C) is prepared from hexahydrophthalic anhydride, trimethylolpropane, 2-butyl-2-ethyl-1,3-propanediol, and optionally dimethyl adipate in a molar mixing ratio of the acid groups to the hydroxyl groups of 1:1 to 1:1.4 and a molar mixing ratio of the acid groups of hexahydrophthalic anhydride to hydroxyl groups of trimethylolpropane of 1:0.9 to 1:1.4 and a molar mixing ratio of the hydroxyl groups of trimethylolpropane to hydroxyl groups of 2-butyl-2-ethyl-1,3-propanediol of greater than 3:1 and stochiometrically less than 0.2 part of dimethyl adipate, based on hexahydrophthalic anhydride.

7. The coating composition according to claim 1 , wherein the polyester polyol (C), besides hexahydrophthalic anhydride, is not prepared using any further diacid or derivative thereof.

8. The coating composition according to claim 1 , wherein the polyester polyol (C) is tin-free, is prepared uncatalyzed or with a catalyst comprising zinc, titanium, zirconium, bismuth, or another non-tin element.

9. The coating composition according to claim 1 , wherein the polyester polyol (C) has been prepared in the absence of solvent.

10. The coating composition according to claim 1 , wherein the polyester polyol (C) has acid numbers of up to 50 mg KOH/g to 100 mg KOH/g, based on solids.

11. The coating composition according to claim 1 , wherein the polyester polyol (C) has a number-average molecular weight Mn of 500 to 4000 g/mol, polydispersity of less than or equal to 5, or both.

12. The coating composition according to claim 1 , wherein the polyester polyol (C) has a glass transition temperature of −20 to 50° C.

13. The coating composition according to claim 1 , wherein the polyester polyol (C) is prepared in a one-stage operation.

14. A method for coating a substrate with the coating composition of claim 1 , which comprises mixing with one another the components (A), (B) and (C), in a molar ratio of isocyanate groups in (A) to isocyanate-reactive groups in (B) and (C) of 1:1.3 to 1.3:1, and subsequently applying this mixture to the substrate.

15. The method according to claim 14 , wherein the substrate comprises a building, a vehicle, an aircraft, a utility vehicle in an agricultural or construction sector, a wind turbine, a decorative finish, a bridge, a power mast, a tank, a container, a pipeline, a power station, a chemical plant, a ship, a crane, a post, sheet piling, a valve, a pipe, a fitting, a flange, a coupling, a hall, a roof, structural steel, furniture, a window, a door, wood flooring, a can coating, a coil coating, a floor covering, or a parking level.

16. The method according to claim 14 , wherein the substrate comprises wood, wood veneer, paper, paperboard, cardboard, textile, film, leather, a nonwoven, a plastics surface, glass, ceramic, a mineral building material, a plastic or a metal, each of which may optionally have been already coated and/or pretreated.

Assignees

• Basf Se

Inventors

• Schaefer Harald
• Tuerp David
• Neu Oliver
• Erhardt Rainer
• Flojhar Daniel
• Pauen Thorsten
• Steinbrecher Angelika Maria
• Haberecht Monika

Classifications

• C08G18/6225

  Polymers of esters of acrylic or methacrylic acid · CPC title

• C09D175/06 Primary

  from polyesters · CPC title

• C08G18/4063

  Mixtures of compounds of group C08G18/62 with other macromolecular compounds · CPC title

• C08G18/4241

  from dicarboxylic acids and dialcohols in combination with polycarboxylic acids and/or polyhydroxy compounds which are at least trifunctional · CPC title

• C08G18/4261

  prepared by oxyalkylation of polyesterpolyols · CPC title