Superhydrophobic and oleophobic coatings with low VOC binder systems

• US 10,240,049 B2
• Filed: 01/13/2017
• Issued: 03/26/2019
• Est. Priority Date: 02/21/2011
• Status: Active Grant

• Current Assignee: ADT Technology LLC
• Original Assignee: Ross Technology Corporation
• Inventors: Gesford, Joshua, Hurley, Michael F., Jones, Andrew K., Lor, Boon Chan, Sikka, Vinod K., Harsh, Philip R.
• Primary Examiner(s): Van Sell, Nathan L
• Application Number:
  US15/406,256
• Publication Number:
  US 20170198154A1
• Time in Patent Office: 802 Days
• CPC Class Codes: C08K 2003/2241 Titanium dioxide
• CPC Class Codes: C08K 9/00 Use of pretreated ingredients
• CPC Class Codes: C08K 9/06 with silicon-containing compounds
• CPC Class Codes: C09D 175/04 Polyurethanes
• CPC Class Codes: C09D 5/1662 Synthetic film-forming substance
• CPC Class Codes: C09D 5/1681 Antifouling coatings characterised by surface structure, e.g. for roughness effect giving superhydrophobic coatings or Lotus effect
• CPC Class Codes: Y10T 428/24355 Continuous and nonuniform or irregular surface on layer or component [e.g., roofing, etc.]

Abstract

Coating compositions for the preparation of superhydrophobic (SH) and/or oleophobic (OP) surfaces that employ low amounts of volatile organic compounds are described. Also described are the resulting coatings/coated surfaces and methods of their preparation. Such coatings/surfaces have a variety of uses, including their ability to prevent or resist water, dirt and/or ice from attaching to a surface.

Claims

1. A coating composition for the application of superhydrophobic, or superhydrophobic and oleophobic, coatings on surfaces comprising:

a one-component waterborne polyurethane dispersion or suspension comprising one or more of a polyester urethane, a polyacrylic urethane and/or a polycarbonate urethane in water, or a water containing medium;

about 5 to about 30% by weight of hydrophobic, or superhydrophobic and oleophobic, second particles comprising one or more siloxanes, and/or one or more alkyl, haloalkyl, fluoroalkyl, or perfluoroalkyl containing moieties;

said composition optionally comprising up to about 26% by weight of third particles;

wherein said coating composition comprises less than 0.3 pounds per gallon of volatile non-exempt organic compounds;

wherein said coating composition optionally comprises first particles;

and

wherein the superhydrophobic coating resulting from the application of said composition to a surface retains its superhydrophobicity after 150-1,400 Taber abrasion cycles at a 1000 g load for a coating thickness range of 25-300 microns, and/or 100-2,500 Taber abrasion cycles at a 250 g load, using a CS10 wheel, as judged by the inability of more than 50% of the water droplets applied to the area of the coating subjected to said abrasion cycles to remain on the surface when the planar surface is inclined at 3 degrees.

2. The composition of claim 1, wherein said composition does not comprise first particles and the superhydrophobic coating resulting from the application of said composition to a planar surface retains its superhydrophobicity after 150-800 Taber abrasion cycles at a 1,000 g load, for a thickness range of 25-75 microns, and/or 200-1,400 Taber abrasion cycles at a 250 g load for a thickness range of 25-75 microns, on a planar surface using a CS10 wheel, as judged by the inability of more than 50% of the water droplets applied to the area of the coating subjected to said abrasion cycles to remain on the surface when the planar surface is inclined at an angle of 3 degrees.

3. The composition of claim 1, wherein said composition further comprises first particles.

4. The composition of claim 3, wherein the first particles are selected from oxides of metalloids, metal oxides, one or more thermoplastics, one or more thermoset plastics, one or more metals, one or more glasses, and/or one or more hollow spheres.

5. The composition of claim 3, wherein the superhydrophobic coating resulting from the application of said composition to a planar surface retains its superhydrophobicity after 100-600 Taber abrasion cycles at a 250 g load for a thickness range of 40-85 microns using a CS10 wheel, as judged by the inability of more than 50% of the water droplets applied to the area of the coating subjected to said abrasion cycles to remain on the surface when the planar surface is inclined at an angle of 3 degrees.

6. The composition of claim 1, wherein said polyurethane suspension or dispersion comprises third particles.

7. The composition of claim 1, wherein the composition comprises a mixture of polyacrylic urethanes and polycarbonate urethanes.

8. The composition of claim 1, wherein said one or more alkyl, haloalkyl, fluoroalkyl, or perfluoroalkyl containing moieties are one or more alkylsilane and/or fluoroalkylsilane groups.

9. The composition of claim 8, wherein said alkylsilane and/or fluoroalkylsilane groups result from the reaction of silica or metal oxide particles with one or more silanes selected from the group consisting of:

a compound of formula I;

(tridecafluoro-1,1,2,2-tetrahydrooctyl)silane;

(tridecafluoro-1,1,2,2-tetrahydrooctyl)trichlorosilane;

(tridecafluoro-1,1,2,2-tetrahydrooctyl)triethoxysilane;

(tridecafluoro-1,1,2,2-tetrahydrooctyl)trimethoxysilane;

(heptadecafluoro-1,1,2,2-tetrahydrodecyl)dimethyl(dimethylamino)silane;

(heptadecafluoro-1,1,2,2-tetrahydrodecyl)tris(dimethylamino)silane;

n-octadecyltrimethoxysilane;

n-octyltriethoxysilane; and

3,3,4,4,5,5,6,6,6-nonafluorohexyldimethyl(dimethylamino)silane.

10. The composition of claim 9, wherein said second particles are present from about 20% to about 30% by weight.

11. The composition of claim 9, wherein said coating is both superhydrophobic and oleophobic.

12. The composition of claim 1, that when dried and cured produces a surface with an arithmetic mean roughness (Ra) of less than about 20 microns.

13. The composition of claim 1, comprising from about 30% to about 50% polyurethanes by weight.

14. The composition of claim 1, wherein said polyurethane dispersion or suspension comprises at least one polyester urethane, polyacrylic urethane, and/or polycarbonate urethane composition that when dried and cured produces a coating that has:

(a) a modulus at 100% elongation of 1300 psi or greater, and/or (b) an elongation percent at break of 150% or greater.

15. The composition of claim 1, further comprising 0.1-10, 10-20, 20-30, 30-40, 40-50 or 50-60 g of one or more compatible solvents per 100 g of coating composition.

16. The composition of claim 15, wherein said one or more compatible solvents are VOC-exempt solvents, and wherein said coating composition comprises less than 0.3 pounds per gallon of volatile non-exempt organic compounds.

17. The composition according to claim 16, wherein said one or more VOC-exempt solvents comprise water.

18. A superhydrophobic and/or oleophobic coating formed by the application of the composition of claim 1.

19. The coating of claim 18, wherein said coating formed on a flat flexible surface can withstand being bent to a right angle around a ¼

inch cylinder greater than about 100 times without loss of hydrophobicity or oleophobicity.

20. A method of coating at least part of a surface comprising the application of a composition of claim 1.