Low gloss UV-cured coatings for aircraft

• US 8,906,468 B2
• Filed: 10/27/2011
• Issued: 12/09/2014
• Est. Priority Date: 10/27/2011
• Status: Active Grant

• Current Assignee: PPG Industries Ohio Incorporated (Nouryon BV)
• Original Assignee: PPG Industries Ohio Incorporated (Nouryon BV)
• Inventors: Bowman, Mark, Muschar, Harry
• Primary Examiner(s): Lightfoot, Elena T
• Application Number:
  US13/282,640
• Publication Number:
  US 20130108798A1
• Time in Patent Office: 1,139 Days
• Field of Search: 427/514
• US Class Current: 427/514
• CPC Class Codes: C09D 4/00 Coating compositions, e.g. paints, varnishes or lacquers, based on organic non-macromolecular compounds having at least one polymerisable carbon-to-carbon unsaturated bond ; Coating compositions, based on monomers of macromolecular compounds of groups C09D183/00 - C09D183/16
• CPC Class Codes: C09D 7/42 Gloss-reducing agents

Abstract

A method of applying a low gloss coating to a substrate such as the exterior surface of an aircraft is disclosed. The coating composition comprising a polyene, a polythiol, a flatting agent and a coloring pigment is applied to the substrate and given a first dosage of UV radiation followed by a second dosage in which the second dosage is greater than the first resulting in an ultralow gloss coating.

Claims

1. A method of providing a cured topcoating on the exterior surface of an aircraft comprising:

(a) spraying manually to a primer coating on the exterior surface of the aircraft a topcoat composition comprising;

(i) a polyene,

(ii) a polythiol,

(iii) 15 to 60 percent by weight of a flatting agent, and

(iv) a coloring pigment that is a mixture of 20 to 50 percent by weight of titanium dioxide and 0.1 to 10 percent by weight of carbon black, the percentages being based on total weight of the coating composition;

(b) forming a film on the exterior surface of the aircraft;

(c) exposing manually the film to a first dosage of UV radiation having a first wavelength range; and

then

(d) exposing manually the film to a second dosage of UV radiation having a second wavelength range wherein the second dosage is greater than the first dosage and the cured film has an 85°

gloss of less than 10.

2. The method of claim 1 wherein the first wavelength range has the strongest wavelength at 395 nm and the second wavelength range has the strongest wavelength at 365 nm.

3. The method of claim 1 wherein the first dosage is from 50 to 10,000 mJ/cm² and the second dosage is from 1000 to 1,000,000 mJ/cm².

4. The method of claim 1 in which the cured coating has a dry film thickness of 5 to 150 microns.

5. The method of claim 1 in which the flatting agent has a particle size of 3 to 75 microns.

6. The method of claim 1 in which the polyene has the structural formula

A-(X) _m

where A is an organic moiety;

X is an olefinically unsaturated moiety and m is at least 2.

7. The method of claim 6 in which X is selected from —

C(O)CR=CH₂ and —

CH₂—

CR=CH₂, where R is hydrogen or methyl.

8. The method of claim 6 in which A contains groups selected from ester and urethane.

9. The method of claim 6 in which A is derived from a polyisocyanate.

10. The method of claim 6 in which A-(X) _m is a polyurethane (meth)acrylate.

11. The method of claim 6 in which A-(X) _m is a polyester (meth)acrylate.

12. The method of claim 9 in which the polyisocyanate is an aliphatic including a cycloaliphatic polyisocyanate.

13. The method of claim 6 in which m is from 2 to 4.

14. The method of claim 1 in which the polythiol has the structural formula R₁(SH)_n where R₁ is an organic moiety and n is at least 2.

15. The method of claim 14 in which R₁ contains ester groups.

16. The method of claim 14 in which R₁ is derived from a polyol.

17. The method of claim 14 in which the polythiol is the reaction product of a thiol-functional organic acid and a polyol.

18. The method of claim 14 in which n is from 2 to 4.

19. The method of claim 1 in which the polyene is present in the topcoat composition in amounts of 80 to 98 percent by weight and the polythiol is present in amounts of 2 to 20 percent by weight;

the percentages by weight being based on weight of polyene and polythiol.

20. The method of claim 1 in which the cured film has an 85°

gloss of 5 or below.