Elastomeric coatings having hydrophobic and/or oleophobic properties

• US 9,388,325 B2
• Filed: 03/28/2014
• Issued: 07/12/2016
• Est. Priority Date: 06/25/2012
• Status: Active Grant

• Current Assignee: ADT Technology LLC
• Original Assignee: Ross Technology Corporation
• Inventors: Jones, Andrew K., Lim, Zenas W., McLean, Andrew, Sikka, Vinod K., Hurley, Michael
• Primary Examiner(s): Shosho, Callie
• Assistant Examiner(s): Nelson, Michael B
• Application Number:
  US14/229,047
• Publication Number:
  US 20140205804A1
• Time in Patent Office: 837 Days
• Field of Search: 428/323, 428/141, 239/337, 523/218, 523/220, 524/263, 427/407.1, 427/141, 427/202
• US Class Current: 1/1
• CPC Class Codes: B65D 83/752 characterised by the use of specific products or propellants
• CPC Class Codes: C08K 5/5406 containing elements other than oxygen or nitrogen
• CPC Class Codes: C08K 7/22 Expanded, porous or hollow particles
• CPC Class Codes: C09D 153/00 Coating compositions based on block copolymers containing at least one sequence of a polymer obtained by reactions only involving carbon-to-carbon unsaturated bonds; Coating compositions based on derivatives of such polymers
• CPC Class Codes: C09D 153/02 Vinyl aromatic monomers and conjugated dienes
• CPC Class Codes: C09D 183/04 Polysiloxanes
• CPC Class Codes: C09D 183/16 in which all the silicon atoms are connected by linkages other than oxygen atoms
• 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: C09D 7/69 Particle size larger than 1000 nm
• CPC Class Codes: Y10T 428/24355 Continuous and nonuniform or irregular surface on layer or component [e.g., roofing, etc.]

Abstract

This disclosure deals with novel formulations to create highly durable hydrophobic, superhydrophobic, oleophobic and/or superoleophobic surfaces that can be nearly transparent. The formulations of this invention can be applied by -dip, spray and painting processes.

Claims

1. A system for forming a coating comprising:

A) a first component which comprises

i) an elastomeric binder comprising one or more styrenic block copolymers, wherein said elastomeric binder comprises from about 1% to about 30% of said one or more styrenic block copolymers by weight;

ii) one or more independently selected first particles having a size of about 30 microns to about 225 microns, wherein the first component comprises from about 0.01% to about 5% of said first particles by weight; and

iii) one or more solvents; and

B) a second component which either comprises

i) one or more independently selected second particles having a size of about 1 nanometer to about 25 microns, wherein said second particles comprise one or more independently selected alkyl, haloalkyl, or perfluoroalkyl moieties bound, either directly or indirectly, to said second particles, and

ii) optionally, one or more solvents;

or comprises per 100 parts by weight;

i) 0.1 to 3.5 parts by weight of one or more independently selected second particles having a size of about 1 nanometer to about 25 microns, wherein said second particles either comprise one or more independently selected alkyl, haloalkyl, or perfluoroalkyl moieties bound directly or indirectly to said second particles, or comprise one or more siloxanes or silazanes associated with said second particles;

ii) 0.1 to 1.0 parts by weight of a fluorinated polyolefin;

or

 

0.06 to 0.6 parts by weight of a Fluoroethylene-Alkyl Vinyl Ether (FEVE) copolymer; and

iii) one or more solvents for a total of 100 parts by weight;

wherein a coating formed by

(a) applying the first component to at least a portion of a surface, wherein the portion of the surface has optionally been treated with a primer on all or part of the surface to which said first component is to be applied; and

(b) applying the second component to all or a portion of the surface coated with the first component in step (a),

results in a coating that has an elongation at break greater than about 200%, an arithmetical mean roughness value from about 3 microns to about 20 microns, or a ten point mean roughness from about 7 microns to about 100 microns, and a total luminous transmittance of about 75% to about 85% as measured by ASTM D1003-11 for a coating about 25 microns thick without added colorants; and

wherein said coating has either hydrophobic or superhydrophobic properties, and optionally is oleophobic or superoleophobic.

2. The system for forming a coating according to claim 1 comprising:

an aerosol spray container containing the first component and a propellant and/or an aerosol spray containing the second component and a propellant.

3. A method of forming a hydrophobic coating on a portion of a surface comprising the steps:

(a) applying a first component to at least a portion of the surface, wherein the portion of the surface has optionally been treated with a primer on all or part of the surface to which said first component is to be applied; and

(b) applying a second component to all or a portion of the surface coated with the first component in step (a),

wherein the first component comprises

i) an elastomeric binder comprising one or more styrenic block copolymers, wherein said elastomeric binder comprises from about 1% to about 30% of said one or more styrenic block copolymers by weight;

ii) one or more independently selected first particles having a size of about 30 microns to about 225microns, wherein the first component comprises from about 0.2% to about 5% of said first particles by weight; and

iii) one or more solvents;

wherein the second component either comprises;

i) one or more independently selected second particles having a size of about 1 nanometer to about 25 microns, wherein said second particles comprise one or more independently selected alkyl, haloalkyl, or perfluoroalkyl moieties bound, either directly or indirectly, to said second particles, and

ii) one or more solvents;

or comprises per 100parts by weight;

i) 0.1to 3.5parts by weight of one or more independently selected second particles having a size of about 1 nanometer to about 25 microns, wherein said second particles either comprise one or more independently selected alkyl, haloalkyl, or perfluoroalkyl moieties bound, directly or indirectly to said second particles, or comprise one or more siloxanes or silazanes associated with said second particles;

ii) 0.1 to 1.0 parts by weight of a fluorinated polyolefin;

or

 

0.06 to 0.6 parts by weight of a Fluoroethylene-Alkyl Vinyl Ether (FEVE) copolymer; and

iii) one or more solvents for a total of 100 parts by weight;

wherein said coating has either hydrophobic or superhydrophobic properties, and optionally is oleophobic or superoleophobic; and

wherein the coating formed by said method has an elongation at break greater than about 200%, an arithmetical mean roughness value from about 3 microns to about 20 microns, or a ten point mean roughness from about 7 microns to about 100 microns, and a total luminous transmittance of about 75% to about 85% as measured by ASTM D1003-11for a coating about 25 microns thick without added colorants.

4. The method of claim 3, wherein one or more of the styrenic block copolymers has a rubber phase crosslinked to a polystyrene phase.

5. The method of claim 4, wherein said rubber phase comprises 60%-80% of the styrenic block copolymers in the elastomeric binder by weight, based on the dry weight of the styrenic block copolymers present in the first component not including any contribution by the first particles or other materials present in the first component.

6. The method of claim 3, wherein one or more of the styrenic block copolymers has a rubber phase comprising polybutadiene, polyisoprene, polyolefin or a mixture of any of those rubber phase components, any one or more of which may optionally comprise 1% to 3% of maleic anhydride.

7. The method of claim 3, wherein said first component further comprises one or more colorants, UV stabilizers, antioxidants, rheological agents, and/or fillers.

8. The method of claim 3, wherein said first component further comprises up to 30% by weight of one or more tackifiers, wherein said one or more styrenic block copolymers and said one or more tackifiers together comprise up to about 30% by weight of said first component.

9. The method of claim 3, wherein said elastomeric binder comprises one or more triblock copolymers.

10. The method of claim 3, wherein said elastomeric binder comprises one or more styrenic block copolymers of styrene and ethylene/butylene with a polystyrene content of about 8% to about 36% by weight, or mixtures of any two or more of such triblock copolymers.

11. The method of claim 3, wherein one or more of said styrenic block copolymers present in the elastomeric binder comprise maleic anhydride or a first and a second maleated triblock copolymer of styrene and ethylene/butylene wherein:

said first maleated triblock copolymer of styrene and ethylene/butylene has a polystyrene content from about 8% to about 14%, with 0.4% to 1.6% substitution of maleic anhydride by weight of the first triblock copolymer; and

said second maleated triblock copolymer of styrene and ethylene/butylene has a polystyrene content of about 22% to about 32%, with 1.1% to 2.5% substitution of maleic anhydride by weight of the second triblock copolymer.

12. The method of claim 3, wherein said first particles are selected from the group consisting of:

glass, ceramic, rubber, plastic, thermoplastic, wood, cellulose, metal oxides, silicon dioxide, silicates, tectosilicates, germanium dioxide, plastic particles, carbide particles, nitride particles, boride particles, spinel particles, diamond particles, fly ash particles, fibers, hollow glass spheres, hollow glass particles, and hollow plastic particles, wherein said first particles optionally comprise a colorant.

13. The method of claim 3, wherein said second particles comprise a metal oxide, an oxide of a metalloid, a silicate, or a glass, wherein said second particles have an average size in the range of from 1 nm to 100 nm or from 2 nm to 200 nm.

14. The method of claim 3, wherein said one or more moieties result from contacting the second particles with one or more silanizing agents of formula (I):

R_4-nSi—

X_n 

 

(I)

where n is an integer from 1 to 3;

each R is independently selected from

(i) alkyl or cycloalkyl group optionally substituted with one or more fluorine atoms,

(ii) C_{1 to 20} alkyl optionally substituted with one or more substituents independently selected from fluorine atoms and C_{6 to 14} aryl groups, which aryl groups are optionally substituted with one or more independently selected halo, C_{1 to 10} alkyl, C_{1 to 10} haloalkyl, C_{1 to 10} alkoxy, or C_{1 to 10} haloalkoxy substituents,

(iii) C_{2 to 8} or C_{6 to 20} alkyl ether optionally substituted with one or more substituents independently selected from fluorine and C_{6 to 14} aryl groups, which aryl groups are optionally substituted with one or more independently selected halo, C_{1 to 10} alkyl, C_{1 to 10} haloalkyl, C_{1 to 10} alkoxy, or C_{1 to 10} haloalkoxy substituents,

(iv) C_{6 to 14} aryl, optionally substituted with one or more substituents independently selected from halo, alkoxy, and haloalkoxy substituents,

(v) C_{4 to 20} alkenyl or C_{4 to 20} alkynyl, optionally substituted with one or more substituents independently selected from halo, alkoxy, or haloalkoxy, or

(vi) —

Z—

((CF₂)_q(CF₃))_r, wherein Z is a C_{1 to 12} or a C_{2 to 8} divalent alkane radical or a C_{2 to 12} divalent alkene or alkyne radical, q is an integer from 1 to 12, and r is an integer from 1 to 4;

each X is independently selected from —

H, —

Cl, —

I, —

Br, —

OH, —

OR², —

NHR³, or —

N(R³)₂ group;

each R² is an independently selected C_{1 to 4} alkyl or haloalkyl group; and

each R³ is an independently selected H, C_{1 to 4} alkyl, or haloalkyl group.

15. The method of claim 14, wherein R is —

Z—

((CF₂)_q(CF₃))_r, wherein Z is a C_{1 to 12} divalent alkane radical or a C_{2 to 12} divalent alkene or alkyne radical, q is an integer from 1 to 12, and r is an integer from 1 to 4.

16. The method of claim 14, wherein n is 3.

17. The method of claim 3, wherein said second particles are treated with an agent selected from the group consisting of:

(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;

nonafluorohexyldimethyl(dimethylamino)silane;

dimethyl dichlorosilane;

hexamethyldisilazane;

octyltrimethoxysilane, and polydimethylsiloxane.

18. The method of claim 3, wherein said first component and said second component each further comprises an independently selected solvent and/or propellant.

19. The method of claim 3, wherein said elastomeric binder has an ultimate strength greater than about 20 Mega Pascals (MPa) according to ASTM D412.

20. The method according to claim 3, wherein applying according to step (b) is repeated to a portion of the coated surface if that portion of the coated surface loses said hydrophobic, superhydrophobic, oleophobic and/or superoleophobic properties, and wherein following the repetition of step (b), the coated surface regains hydrophobic, superhydrophobic, oleophobic and/or superoleophobic properties.

21. The method according to claim 3, wherein both steps (a) and (b) are repeated on a portion of the coated surface if that portion of the coated surface loses said hydrophobic, superhydrophobic, oleophobic and/or superoleophobic properties, and wherein following the repetition of steps (a) and (b), the coated surface regains hydrophobic, superhydrophobic, oleophobic and/or superoleophobic properties.

22. A hydrophobic coating prepared by the method according to claim 3.

23. The hydrophobic coating of claim 22, wherein said coating is superhydrophobic or superhydrophobic and superoleophobic.

24. The hydrophobic coating according to claim 22, wherein said coating has an ultimate strength greater than about 20 mega Pascals (MPa) according to ASTM D412.

25. The hydrophobic coating according to claim 22, wherein said coating has a modulus at 100% elongation of greater than 10 mega Pascals (MPa) according to ASTM D412.

26. The hydrophobic coating according to claim 22, having an elongation at break of greater than about 300%.

27. The hydrophobic coating according to claim 22, having a total luminous transmittance of about 75% to about 85% and a haze of about 85% to about 90% as measured by ASTM D1003-11 for a coating about 25 microns thick without added colorants.

28. The hydrophobic coating according to claim 22, wherein said coating is superhydrophobic and retains its superhydrophobicity after being subjected to greater than 20 cycles on a Taber Abraser using CS-0 or CS-10 wheels and a 250 gram load at room temperature, wherein the end of superhydrophobicity is determined to be the point when more than half of the water droplets applied to the portion of the surface subject to the action of the wheels do not roll off the surface when the surface is inclined at a 5 degree angle at room temperature.

29. The hydrophobic coating according to claim 22, wherein said coating is superhydrophobic and when said coating is applied to a planar surface, it continues to display superhydrophobic behavior after being subjected to a continuous shower test of about six liters of water per minute at about 20°

C.-25°

C. for greater than 0.3 hours, wherein the end of superhydrophobic behavior is determined to be the time when more than half of the water droplets applied to a portion of the surface subject to said shower do not roll off the surface when it is inclined at a 5 degree angle at room temperature,

wherein the shower test is conducted using a showerhead with 70 nozzles with a 1 mm diameter orifice arranged in 5 spokes of 5 nozzles and 15 spokes of 3nozzles about a central point on a circular showerhead, and wherein the showerhead delivers approximately 6 liters of potable tap water per minute using about 137900 Pa (Pascals) to 310275 Pa, and wherein the coating is placed about 1.5 meters below the showerhead.