High performance aqueous coating compositions
View Patent ↗This invention relates to coating compositions that include water; a latex polymer and a silane coupling agent. The latex polymer preferably comprises acetoacetoxy functionality, or is a multistage latex, or is an acetoacetoxy functional multistage latex. The silane coupling agent is preferably a functionalized silane coupling agent (more preferably an epoxy-functional silane coupling agent). The compositions may be used to coat a variety of substrates, including wood, cement and fiber cement. Articles having the coating applied thereto are also provided.
1. A coated substrate, comprising:
a cementitious substrate having at least one major surface; and
a coating composition applied to the major surface, the coating composition comprising a mixture of water, a multistage latex polymer having acetoacetoxy functionality, and about 0.25 to about 10 weight % based on the total latex polymer weight of an epoxy-functional silane coupling agent that provides improved resistance to delamination from the substrate when a hardened coating made from the composition is exposed for one hour at 60° C. to 1,034 kPa pressure from an automotive tire tread section heated to 60° C.
2. The substrate of claim 1 , wherein the multistage latex polymer comprises at least one soft stage having a Tg between about −65 and 30° C. and at least one hard stage having a Tg between about 30 and 230° C.
3. The substrate of claim 2 , wherein the multistage latex polymer comprises 50 to 90 weight % soft stage polymer morphology having a Tg between about −5 and 25° C. and 10 to 50 weight % hard stage polymer morphology having a Tg between about 30 and 105° C., based on total polymer weight.
4. The substrate of claim 1 , wherein the multistage latex polymer has a gradient Tg.
5. The substrate of claim 1 , wherein the multistage latex polymer was made from 0.5 to 10 weight % acetoacetoxy functional monomer based on the total polymer weight.
6. The substrate of claim 1 , wherein the coating composition comprises at least about 10 weight % multistage latex polymer based on total coating composition solids, and about 0.25 to 5 weight % silane coupling agent based on the total latex polymer weight.
7. The substrate of claim 1 , wherein the coating composition includes less than 10 weight % volatile organic compounds and at least 1 weight % low VOC coalescent.
8. The composition of claim 1 , wherein the composition resists crush when two face-to-face coated embossed substrates are subjected to a pressure of 8 kg/cm 2 .
9. A coated substrate, comprising:
a cementitious substrate having at least one major surface; and
a coating composition applied to the major surface, the coating composition comprising a mixture of water, a latex polymer having acetoacetoxy functionality, and about 0.25 to about 10 weight % based on the total latex polymer weight of an epoxy-functional silane coupling agent that provides improved resistance to delamination from the substrate when a hardened coating made from the composition is exposed for one hour at 60° C. to 1,034 kPa pressure from an automotive tire tread section heated to 60° C.
10. The substrate of claim 8 , wherein the latex polymer comprises at least one soft stage having a Tg between about −65 and 30° C. and at least one hard stage having a Tg between about 30 and 230° C.
11. The substrate of claim 8 , wherein the latex polymer was made from 0.5 to 10 weight % acetoacetoxy functional monomer based on the total polymer weight.
12. The substrate of claim 8 , wherein the coating composition comprises at least about 10 weight % latex polymer based on total coating composition solids, and about 0.25 to 5 weight % silane coupling agent based on the total latex polymer weight.
13. The substrate of claim 8 , wherein the coating composition includes less than 10 weight % volatile organic compounds and at least 1 weight % low VOC coalescent.
14. A method for preparing a coated substrate comprising
providing a cementitious substrate;
coating at least a portion of the substrate with a coating composition comprising water, a multistage latex polymer having acetoacetoxy functionality, and about 0.25 to about 10 weight % based on the total latex polymer weight of an epoxy-functional silane coupling agent; and
allowing the coating to harden
wherein the silane coupling agent provides improved resistance to delamination from the substrate when the hardened coating is exposed for one hour at 60° C. to 1,034 kPa pressure from an automotive tire tread section heated to 60° C.
15. A method for preparing a coated substrate comprising
providing a cementitious substrate;
coating at least a portion of the substrate with a coating composition comprising water, a latex polymer having acetoacetoxy functionality, and about 0.25 to about 10 weight % based on the total latex polymer weight of an epoxy-functional silane coupling agent; and
allowing the coating to harden
wherein the silane coupling agent provides improved resistance to delamination from the substrate when the hardened coating is exposed for one hour at 60° C. to 1,034 kPa pressure from an automotive tire tread section heated to 60° C.