US-12624246-B2 - Curable film-forming compositions and coated structures with improved corrosion resistance and durability

Abstract

The present invention is directed to curable film-forming compositions and coating kits comprising: (1) a resinous component comprising: (a) an acrylic polyol; (b) an aliphatic ketimine that is substantially free, essentially free and/or completely free of silane functional groups; and optionally (c) a polyaspartic ester; and (2) a curing agent comprising at least two different aliphatic polyisocyanates. The present invention is further directed to coated structures comprising: (a) a component of a vehicle, building, bridge, industrial protective structure, construction equipment structure, ship, railcar, railcar container, water tower, power line tower, tunnel, oil or gas industry structure, marine structure, aerospace structure, bridge support structure, pipeline, oil rig, storage tank, or wind turbine, wherein the component comprises a metal substrate; and (b) a cured coating formed from the curable film-forming composition described above, applied directly or indirectly to at least one surface of the substrate.

Inventors

• César Alejandro Bernabé Nava Ortiz
• Ganesh Desai

Assignees

• PPG INDUSTRIES OHIO, INC.

Dates

Publication Date

20260512

Application Date

20220224

Claims (20)

1. 1 . A curable film-forming composition comprising: (1) a resinous component comprising: (a) an acrylic polyol; (b) an aliphatic ketimine that is substantially free of silane functional groups; and optionally (c) a polyaspartic ester; and (2) a curing agent comprising at least two different aliphatic polyisocyanates, wherein the curable film-forming composition comprises less than 10 percent by weight of a polyisocyanate polymer or prepolymer, based on the total weight of the curable film-forming composition.
2. 2 . The curable film-forming composition of claim 1 , wherein the polyaspartic ester (c) is present.
3. 3 . The curable film-forming composition of claim 1 , wherein the acrylic polyol (a) has a hydroxyl equivalent weight of at least 650 g/equivalent, and at most 750 g/equivalent, and wherein the acrylic polyol is prepared from a monomer mixture comprising butyl acrylate and 2-hydroxyethyl acrylate.
4. 4 . The curable film-forming composition of claim 1 , wherein the equivalent ratio of isocyanate functional groups in the curing agent (2) to total active hydrogen functional groups in the resinous component (1) is 1:1 to 1.2:1.
5. 5 . The curable film-forming composition of claim 1 , wherein the aliphatic polyisocyanates comprise at least two of 4,4′-methylene-bis(cyclohexyl isocyanate), isophorone diisocyanate, 2,2,4-trimethyl hexamethylene diisocyanate, 2,4,4-trimethyl hexamethylene diisocyanate, 1,6-hexamethylene diisocyanate, a biuret of one or more of the preceding aliphatic polyisocyanates, and an isocyanurate of one or more of the preceding aliphatic polyisocyanates.
6. 6 . The curable film-forming composition of claim 1 , wherein after application of the curable film-forming composition to a substrate and after curing to form a cured coating, the cured coating demonstrates a 20° surface gloss greater than 70 and less than 95, and a 60° surface gloss of greater than 85 and less than 98, as measured according to ASTM D-523-14.
7. 7 . The curable film-forming composition of claim 1 , wherein the curable film-forming composition has a solids content of at least 60 percent by weight and at most 80 percent by weight, based on the total weight of the curable film-forming composition.
8. 8 . The curable film-forming composition of claim 1 , wherein the curable film-forming composition comprises separate packages, wherein a first package comprises the resinous component (1) and the matting agent (3) if present; and wherein a second package comprises the curing agent (2); and wherein the packages are separate from one another until immediately prior to application of the curable film-forming composition to a substrate.
9. 9 . The curable film-forming composition of claim 1 , wherein the resinous component (1) further comprises (d) a polyester polyol.
10. 10 . The curable film-forming composition of claim 1 , wherein the aliphatic ketimine (b) is prepared from a reaction mixture comprising: (1) a diamine comprising isophorone diamine, ethylene diamine, 1,2-diaminopropane, 1,4-diaminobutane, 1,5-diaminopentane, 1,6-diaminohexane, 1,8-diaminooctane, 2-methyl-1,5-pentane diamine, 2,5-diamino-2,5-dimethylhexane, 2,2,4-trimethyl-1,6-diamino-hexane, 2,4,4-trimethyl-1,6-diamino-hexane, 1,11-diaminoundecane, 1,12-diaminododecane, 1,3-cyclohexane diamine, 1,4-cyclohexane diamine, 1-amino-3,3,5-trimethyl-5-aminomethyl-cyclohexane, 2,4′-diamino-dicyclohexyl methane, 4,4′-diamino-dicyclohexyl methane, 3,3′-dimethyl-4,4′-diamino-dicyclohexyl methane and/or 3,3′-diethyl-4,4′-diamino-dicyclohexyl methane; and (2) a ketone comprising acetone, methyl ethyl ketone, methyl isobutyl ketone, and/or methyl amyl ketone.
11. 11 . The curable film-forming composition of claim 10 , wherein the aliphatic ketimine (b) is prepared from a reaction mixture comprising isophorone diamine and methyl isobutyl ketone.
12. 12 . The curable film-forming composition of claim 1 , further comprising (3) a matting agent present in the curable film-forming composition in an amount of 3 to 5 percent by weight, based on the total weight of the curable film-forming composition, wherein the matting agent comprises (a) precipitated silica that is surface treated with wax and that demonstrates a number average d50 particle size of 5 to 7 microns, as measured by Test Method ISO 13320-2009 using laser diffraction; and (b) organic polymeric particles that demonstrate a density of 1.4 to 2.0 g/cm 3 , as measured by Test Method ISO 787-10, and a volume average d50 particle size of 4 to 6 microns, as measured by Test Method ISO 13320-2009 using laser diffraction.
13. 13 . The curable film-forming composition of claim 12 , wherein after application of the curable film-forming composition to a substrate and after curing to form a cured coating, the cured coating demonstrates a 20° surface gloss greater than 5 and less than 15, and a 60° surface gloss of greater than 40 and less than 50, as measured according to ASTM D-523-14.
14. 14 . A coated structure comprising: (a) a component of a vehicle, building, bridge, industrial protective structure, construction equipment structure, ship, railcar, railcar container, water tower, power line tower, tunnel, oil or gas industry structure, marine structure, aerospace structure, bridge support structure, pipeline, oil rig, storage tank, or wind turbine, wherein said component comprises a metal substrate; and (b) a cured coating, wherein the cured coating is formed from the curable film-forming composition of claim 1 applied to at least one surface of the substrate.
15. 15 . The coated structure of claim 14 , wherein the polyaspartic ester is present in the curable film-forming composition, and the curable film-forming composition is applied directly to at least one surface of the substrate.
16. 16 . The coated structure of claim 14 , wherein the substrate comprises one or more of a ferrous metal, aluminum, an aluminum alloy, copper, and brass.
17. 17 . The coated structure of claim 16 , wherein the substrate comprises profiled steel.
18. 18 . A coating kit comprising: (1) a resinous component comprising: (a) an acrylic polyol; and (b) an aliphatic ketimine that is substantially free of silane functional groups; and optionally (c) a polyaspartic ester; and (2) a curing agent comprising at least two different aliphatic polyisocyanates, wherein the coating kit comprises less than 10 percent by weight of a polyisocyanate polymer or prepolymer, based on the total weight of the coating kit.
19. 19 . The coating kit of claim 18 comprising multiple, separate packages, wherein a first package comprises the resinous component (1), and a second package comprises the curing agent (2).
20. 20 . The coating kit of claim 18 , wherein the resinous component (1) further comprises (d) a polyester polyol.

Description

CROSS REFERENCE TO RELATED APPLICATIONS This application is a national stage filing of international patent application PCT/US22/70804, filed Feb. 2, 2022, titled “CURABLE FILM-FORMING COMPOSITIONS AND COATED STRUCTURES WITH IMPROVED CORROSION RESISTANCE AND DURABILITY”, which in turn claims priority to U.S. Provisional Application No. 63/180,904, filed Apr. 28, 2021, titled “CURABLE FILM-FORMING COMPOSITIONS AND COATED STRUCTURES WITH IMPROVED CORROSION RESISTANCE AND DURABILITY”. Both of the above priority documents are incorporated herein by reference in their entireties. FIELD OF THE INVENTION The present invention relates to curable film-forming compositions that demonstrate fast curing, improved corrosion resistance and durability properties, and to coated structures comprising these compositions. BACKGROUND OF THE INVENTION Currently, in the world industrial coatings market there is a need to have anticorrosive coatings that once applied, cure almost immediately, thus optimizing the operation times where these coatings, called “snap cure”, are used. Coatings with excellent performance properties and that do not stop production lines are particularly sought after. There are different polyaspartic products in the coatings market that offer good performance and curing properties. However, most of them are designed for the flooring industry. They offer excellent abrasion and chemical resistance properties, which are necessary and indispensable features in the flooring market, but none of them are intended as a direct-to-metal (DTM) coating, much less guarantee an excellent anticorrosive property when used in an industrial setting where substrates are subjected to long-term exposure to weather extremes and the elements. Outdoor structures such as wind turbines, bridges, towers, and tanks, and fleet vehicles such as railcars, buses, trucks, construction vehicles and aircraft are constantly exposed to the elements and must be designed to endure temperature extremes, wind shears, precipitation, and other changing environmental conditions and hazards without significant damage or the need for constant maintenance, which may be time-consuming and costly. Likewise, marine structures such as ship hulls and off-shore oil rigs and wind turbines are also exposed to seawater as well as extreme weather and other environmental conditions, making them susceptible to corrosion. It would be desirable to provide a curable film-forming composition with DTM capabilities (i. e., appropriate adhesion when applied directly to a metal surface), excellent performance properties, and short drying time, for the preparation of coated structures that will be exposed to long-term environmental conditions. SUMMARY OF THE INVENTION The present invention is directed to curable film-forming compositions and coating kits comprising: (1) a resinous component comprising: (a) an acrylic polyol; and(b) an aliphatic ketimine that is substantially free, essentially free and/or completely free of silane functional groups; and optionally(c) a polyaspartic ester; and (2) a curing agent comprising at least two different aliphatic polyisocyanates. The curable film-forming composition or kit comprises less than 10 percent by weight, or less than 5 percent by weight, or less than 2 percent by weight, or 0 percent by weight of a polyisocyanate polymer or prepolymer, based on the total weight of the curable film-forming composition or kit. The present invention is further directed to coated structures comprising: (a) a component of a vehicle, building, bridge, industrial protective structure, construction equipment structure, ship, railcar, railcar container, water tower, power line tower, tunnel, oil or gas industry structure, marine structure, aerospace structure, bridge support structure, pipeline, oil rig, storage tank, or wind turbine, wherein said component comprises a metal substrate; and(b) a cured coating formed from the curable film-forming composition described above, applied directly to at least one surface of the substrate. DETAILED DESCRIPTION OF THE INVENTION Other than in the operating examples, or unless otherwise expressly specified, all of the numerical ranges, amounts, values and percentages such as those for amounts of materials, times and temperatures of reaction, ratios of amounts, values for molecular weight (whether number average molecular weight (“Mn”) or weight average molecular weight (“Mw”), each of which may be determined by gel permeation chromatography using a polystyrene standard), and others in the following portion of the specification may be read as if prefaced by the word “about” even though the term “about” may not expressly appear with the value, amount or range. Accordingly, unless indicated to the contrary, the numerical parameters set forth in the following specification and attached claims are approximations that may vary depending upon the desired properties sought to be obtained by the presen