Solar heat reflective roofing membrane and process for making the same

1. A process for preparing a roofing membrane with solar heat-reflectance, the process comprising:

laminating a tie-layer to a bituminous base sheet to form an intermediate sheet, the bituminous base sheet comprising a continuous substrate sheet of fibrous material, the continuous substrate sheet being saturated with a bituminous material and coated on at least one side with a bituminous material;

depositing a solar heat-reflective polymeric coating composition directly on the intermediate sheet;

curing the solar heat-reflective polymeric coating composition to form a solar heat-reflective coating; and

depositing an upper coating composition directly on the solar heat-reflective coating to form an upper coating layer;

wherein the tie-layer is laminated to the bituminous base sheet by heating the surface of the base sheet to above the softening temperature of the bituminous material, and adhering the tie-layer to the base sheet by contacting the base sheet with the tie-layer and permitting the bituminous material to partially saturate the tie-layer.

2. A process according to claim 1 wherein the solar heat-reflective polymeric coating composition is deposited by curtain coating.

3. A process according to claim 1 wherein the solar heat-reflective polymeric coating composition is deposited by electrostatic spray coating.

4. A process according to claim 1 wherein the upper coating composition is formulated to provide exterior durability.

5. A process according to claim 4 wherein the upper coating composition comprises at least one of a fluoropolymer, a UV-curable coating, an acrylic latex based coating, or a silicone emulsion.

6. A process according to claim 1 wherein the tie-layer is formed from a reinforcement material.

7. A process according to claim 6 wherein the reinforcement material is selected from the group consisting of non-woven glass fiber mats, non-woven polyester mats, composite non-woven mats of various fibers, composite woven fabrics of various fibers, industrial fabrics such as papermaker's forming fabrics and papermaker's canvasses, polymer netting, screen, and mineral particles.

8. A process according to claim 1 wherein the tie-layer has a thickness of from about 0.001 cm to about 0.1 cm.

9. A process for preparing a roofing membrane with solar heat-reflectance, the process comprising:

depositing a solar heat-reflective polymeric coating composition directly on a tie-layer to form an intermediate sheet;

curing the solar heat-reflective polymeric coating composition to form a solar heat-reflective coating on top of the tie-layer;

laminating the tie-layer of the intermediate sheet directly to a bituminous base sheet, the bituminous base sheet comprising a continuous substrate sheet of fibrous material, the continuous substrate sheet being saturated with a bituminous material and coated on at least one side with a bituminous material; and

depositing an upper polymeric coating composition directly on the solar heat-reflective coating to form an upper coating layer;

wherein the tie-layer is laminated to the bituminous base sheet by heating the surface of the base sheet to above the softening temperature of the bituminous material, and adhering the tie-layer to the base sheet by contacting the base sheet with the tie-layer and permitting the bituminous material to partially saturate the tie-layer.

10. A process according to claim 9 wherein the solar heat-reflective polymeric coating composition is deposited by curtain coating.

11. A process according to claim 9 wherein the upper polymeric coating composition is deposited by curtain coating.

12. A process according to claim 9 wherein the solar heat-reflective polymeric coating composition is deposited by electrostatic spray coating.

13. A process according to claim 9 wherein the upper polymeric coating comprises at least one of a fluoropolymer, a UV-curable coating, an acrylic latex based coating, or a silicone emulsion.

14. A process according to claim 9 wherein the tie-layer is formed from a reinforcement material selected from the group consisting of non-woven glass fiber mats, non-woven polyester mats, composite non-woven mats of various fibers, composite woven fabrics of various fibers, industrial fabrics such as papermaker's forming fabrics and papermaker's canvasses, polymer netting, screen, and mineral particles.

15. A process according to claim 9 wherein the tie-layer has a thickness of from about 0.001 cm to about 0.1 cm.

16. A method of constructing a roof having solar heat reflectance, the method comprising adhering to a roofing deck a roofing membrane with solar heat reflectance, the roofing membrane comprising:

a bituminous base sheet comprising a continuous substrate sheet of fibrous material, the continuous substrate sheet being saturated with a bituminous material and coated on at least one side with a bituminous material;

a tie-layer comprising a reinforcement material laminated directly to the bituminous base sheet;

a solar heat-reflective layer deposited directly onto the tie-layer; and

a protective top coating deposited directly onto the solar heat-reflective layer;

wherein the tie-layer is laminated to the bituminous base sheet by heating the surface of the base sheet to above the softening temperature of the bituminous material, and adhering the tie-layer to the base sheet by contacting the base sheet with the tie-layer and permitting the bituminous material to partially saturate the tie-layer.

17. A process according to claim 16 wherein the solar-heat reflective layer is deposited by spray coating.

18. A process according to claim 16 wherein the solar-heat reflective layer is deposited by electrostatic spray coating.

19. A process according to claim 16 wherein the protective top coating comprises at least one of a fluoropolymer, a UV-curable coating, an acrylic latex based coating, or a silicone emulsion.

20. A process according to claim 16 wherein the tie-layer is formed from a reinforcement material selected from the group consisting of non-woven glass fiber mats, non-woven polyester mats, composite non-woven mats of various fibers, composite woven fabrics of various fibers, industrial fabrics such as papermaker's forming fabrics and papermaker's canvasses, polymer netting, screen, and mineral particles.