Coating compositions for polymeric roofing materials
A latex emulsion may include an aqueous carrier liquid and a latex copolymer formed from reactants comprising butyl methacrylate, wherein the reactants include at least 20 wt. % butyl methacrylate, based on the total weight of ethylenically unsaturated monomers used to make the latex copolymer. A coating formed from the latex emulsion exhibits a wet adhesion to a thermoplastic polyolefin roofing membrane of greater than about 1 pound per linear inch when tested using fabric embedded peel adhesion testing per ASTM C794. The latex emulsion may be used as part of an aqueous coating composition or a roofing system including a polymeric roofing membrane.
1. A composition comprising:
an aqueous carrier liquid; and
a latex copolymer formed from reactants comprising a chain transfer agent and a vinyl monomer having an alkyl group including between 2 and 20 carbon atoms, wherein the reactants comprise between 20 wt. % and 60 wt. % of the vinyl monomer having an alkyl group including between 2 and 12 carbon atoms, based on the total weight of ethylenically unsaturated monomers used to make the latex copolymer, and wherein a homopolymer formed from the vinyl monomer exhibits a glass transition temperature of between about −10° C. and about 30° C.;
wherein the latex copolymer exhibits a gel fraction of between 0% and about 10%, and wherein the solubilized portion of the latex copolymer exhibits a weight average molecular weight of less than about 230,000 g/mol;
wherein the latex copolymer exhibits a glass transition temperature of between about −50 ° C. and about −15° C.; and
wherein a coating formed from the composition exhibits a wet adhesion to a thermoplastic polyolefin roofing membrane of greater than about 1 pound per linear inch when tested using fabric embedded peel adhesion testing per ASTM D903 at a coverage of about 80 ft 2 /gallon.
2. The composition of claim 1 , wherein the vinyl monomer comprises butyl methacrylate, ethylhexyl methacrylate, a vinyl ester of neodecanoic acid, or combinations thereof.
3. The composition of claim 2 , wherein the butyl methacrylate, ethylhexyl methacrylate, the vinyl ester of neodecanoic acid, or combinations thereof comprises n-butyl methacrylate or a mixture of n-butyl methacrylate and ethylhexyl methacrylate.
4. The composition of claim 1 , further comprising a dispersant, a biocide, a fungicide, an UV stabilizer, a thickener, a wetting agent, a defoamer, a filler, a pigment or colorant, or combinations thereof.
5. The composition of claim 1 , wherein the reactants comprise between 30 wt. % and 60 wt. % of the vinyl monomer having an alkyl group including between 2 and 20 carbon atoms, based on the total weight of ethylenically unsaturated monomers used to make the latex copolymer.
6. The composition of claim 1 , wherein the reactants comprise between 20 and 50 wt. % of the vinyl monomer having an alkyl group including between 2 and 20 carbon atoms, based on the total weight of ethylenically unsaturated monomers used to make the latex copolymer.
7. The composition of claim 1 , wherein the reactants further comprise:
an ethylenically unsaturated polar monomer.
8. The composition of claim 7 , wherein the chain transfer agent comprises dodecyl mercaptan.
9. The composition of claim 1 , wherein the reactants further comprise a second (meth)acrylate, wherein the second (meth)acrylate forms a homopolymer that has a glass transition temperature that is less than −25° C.
10. The composition of claim 9 , wherein the second (meth)acrylate comprises 2-ethylhexyl acrylate.
11. The composition of claim 1 , wherein the reactants further comprise a ureido-functional ethylenically unsaturated monomer.
12. The composition of claim 1 , wherein the coating formed from the composition exhibits a wet adhesion of greater than about 2 pounds per linear inch when tested using fabric embedded peel adhesion testing per ASTM D903.
13. The composition of claim 1 , wherein the latex copolymer exhibits a glass transition temperature of between about −50° C. and about −20° C.
14. A roofing system comprising:
a polymeric roofing membrane; and
a coating on a surface of the polymeric roofing membrane, wherein the coating is formed from a composition comprising:
an aqueous carrier liquid; and
a latex copolymer formed from reactants comprising a chain transfer agent and a vinyl monomer having an alkyl group including between 2 and 20 carbon atoms, wherein the reactants comprise between 20 wt. % and 60 wt. % of the vinyl monomer having an alkyl group including between 2 and 12 carbon atoms, based on the total weight of ethylenically unsaturated monomers used to make the latex copolymer, and wherein a homopolymer formed from the vinyl monomer exhibits a glass transition temperature of between about −10° C. and about 30° C.;
wherein the latex copolymer exhibits a glass transition temperature of between about −50° C. and about −15° C.; and
wherein a coating formed from the coating composition exhibits a wet adhesion to a thermoplastic polyolefin roofing membrane of greater than about 1 pound per linear inch when tested using fabric embedded peel adhesion testing per ASTM D903 at a coverage of about 80 ft 2 /gallon.
15. The roofing system of claim 14 , wherein the polymeric roofing membrane comprises a thermoplastic polyolefin, ethylene propylene diene monomer rubber, or poly(vinyl chloride) roofing membrane.
16. The roofing system of claim 14 , wherein the coating comprises a primer coat, further comprising a top coat on the primer coat.
17. A method comprising:
reacting reactants comprising a chain transfer agent and a vinyl monomer having an alkyl group including between 2 and 20 carbon atoms to form a latex emulsion including a latex copolymer, wherein the reactants comprise between 20 wt. % and 60 wt. % of the vinyl monomer having an alkyl group including between 2 and 20 carbon atoms, based on the total weight of ethylenically unsaturated monomers used to make the latex copolymer, wherein a homopolymer formed from the vinyl monomer exhibits a glass transition temperature of between about −10° C. and about 30° C., wherein the latex copolymer exhibits a gel fraction of between 0% and about 5%, and wherein the solubilized portion of the latex copolymer exhibits a weight average molecular weight of less than about 230,000 g/mol, wherein the latex copolymer exhibits a glass transition temperature of between about −50° C., and about −15° C., and wherein a coating formed from the latex emulsion exhibits a wet adhesion to a thermoplastic polyolefin roofing membrane of greater than about 1 pound per linear inch when tested using fabric embedded peel adhesion testing per ASTM D903 at a coverage of about 80 ft 2 /gallon.
18. The method of claim 17 , wherein the vinyl monomer comprises butyl methacrylate, ethylhexyl methacrylate, a vinyl ester of neodecanoic acid, or combinations thereof.
19. The method of claim 18 , wherein the butyl methacrylate, ethylhexyl methacrylate, the vinyl ester of neodecanoic acid, or combinations thereof comprises n-butyl methacrylate or a mixture of n-butyl methacrylate and ethylhexyl methacrylate.