Anchored polysiloxane-modified polyurethane coatings and uses thereof
A polymeric material, prepared by reacting a mixture comprising a polyorganosiloxane having one or more isocyanate-reactive functional groups, polyisocyanate, and polyol, is provided. The isocyanate-reactive functional groups, typically one or two, are attached to only a single end of the polyorganosiloxane chains. The polymeric material may be used to form coatings on a substrate and to inhibit fouling on surfaces exposed to aqueous conditions.
1. A polymeric material formed from reactants which comprise:
polyorganosiloxane having two or more reactive functional groups attached to only a single end of the polyorganosiloxane; wherein the reactive functional groups are hydroxyl alkyl carbamate groups or amino groups; wherein the polyorganosiloxane constitutes about 5 to 30 wt. % (on a solids basis) of the total weight of the reactants;
about 30 wt. % to 85 wt. % polyisocyanate (on a solids basis) of the total weight of the reactants; and
polyol.
2. The polymeric material of claim 1 , wherein the polyorganosiloxane is an amino functional polyorganosiloxane having two or more amino groups attached to only a single end of the polymer chain.
3. The polymeric material of claim 2 , wherein the polyorganosiloxane includes poly(dialkylsiloxane) having two or more amino groups attached to only a single end thereto.
4. The polymeric material of claim 2 , wherein the polyisocyanate comprises hexamethylene diisocyanate trimer, isophorone diisocyanate trimer, or a mixture thereof.
5. The polymeric material of claim 1 , wherein the polyorganosiloxane has a formula I:
where R′Si— is a terminal group;
n is about 10 to 1,000;
LINK is a linking group;
X is —NH 2 ; and
y is an integer from 2 to 4.
6. The polymeric material of claim 5 , wherein LINK is an alkylene group which may have one or more oxygen, nitrogen or sulfur atoms substituted for a carbon atom of its backbone.
7. The polymeric material of claim 5 , wherein the LINK has no more than about 10 atoms in its backbone and R′Si— is a trialkylsilyl group.
8. The polymeric material of claim 1 , wherein the polymeric material has an initial water contact angle of at least about 100°.
9. The polymeric material of claim 1 , wherein the mixture has a ratio of (isocyanate groups)/(amine+alcohol groups) of about 1.0 to 1.2.
10. A coating composition comprising the reactants of claim 1 .
11. A method of inhibiting fouling on a surface exposed to aqueous conditions comprising applying the coating composition of claim 10 to the surface.
12. A substrate having a surface capable of being exposed to aqueous conditions; wherein the surface has a fouling release coating thereon; and the coating comprises the polymeric material of claim 1 .
13. The polymeric material of claim 1 , wherein the polyol comprises hydroxy-functional poly(meth)acrylate formed from monomers comprising hydroxyalkyl acrylate and alkyl acrylate.
14. The polymeric material of claim 1 , wherein the polyol comprises polycaprolactone polyol.
15. The polymeric material of claim 1 , wherein the polyorganosiloxane comprises a poly(dimethylsiloxane) having two or more amino groups attached to only a single end of the polymer chain;
the polyisocyanate comprises isophorone diisocyanate, hexamethylene diisocyanate, oligomers thereof or a mixture thereof;
the polyol comprises hydroxy-functional poly(mcth)acrylate; and
the reactants have a ratio of (isocyanate groups)/(amine+alcohol groups) of about 1.05 to 1.15.
16. A polymeric material formed from reactants which comprise:
amino functional polyorganosiloxane having one or more amino groups attached to only a single end of the polymer chain, wherein the amino functional polyorganosiloxane constitutes about 5 to 30 wt. % (on a solids basis) of the total weight of the reactants;
polyisocyanate, which constitutes about 30 wt. % to 85 wt. % (on a solids basis) of the total weight of the reactants; and
polyol;
wherein the polymeric material has an initial water contact angle of at least about 100°.
17. The polymeric material of claim 16 , wherein the polyol comprises hydroxy-functional poly(meth)acrylate.
18. The polymeric material of claim 16 , wherein the reactants have a ratio of (isocyanate groups)/(amine+alcohol groups) of about 1.0 to 1.2.
19. The polymeric material of claim 16 , wherein the amino functional polyorganosiloxane constitutes about 5 to 15 wt. % (on a solids basis) of the total weight of the reactants;
the polyisocyanate constitutes about 57 wt. % to 65 wt. % (on a solids basis) of the total weight of the reactants; and
the reactants have a ratio of (isocyanate groups)/(amine+alcohol groups) of about 1.0 to 1.2.
20. The polymeric material of claim 16 , wherein the water contact angle changes by no more than about 10° after immersion of the polymeric material in deionized water for 30 days.
21. The polymeric material of claim 16 , wherein the polyisocyanate is isophorone diisocyanate, hexamethylene diisocyanate or methylene diphenyl diisocyanate; and the amino functional-polyorganosiloxane has a number average molecular weight of about 1,000 to 20,000.
22. The polymeric material of claim 16 , wherein the amino functional polyorganosiloxane has a number average molecular weight of about 1,000 to 20,000 and comprises poly(dialkylsiloxane) having one or more amino groups attached to only a single end thereto;
the reactants have a ratio of (isocyanate groups)/(amine+alcohol groups) of about 1.05 to 1.15;
and
the polyol comprises hydroxy-functional poly(meth)acrylate formed from monomers comprising hydroxyalkyl acrylate and alkyl acrylate.
23. The polymeric material of claim 22 , wherein the amino functional polyorganosiloxane comprises an aminoalkyl terminated poly(dimethylsiloxane); and the polyisocyanate comprises isophorone diisocyanate, hexamethylene diisocyanate, oligomers thereof or a mixture thereof.