Roofing granules with improved luster, roofing products including such granules, and process for preparing same

Patent metadata

Field	Value
Publication number	US-10309111-B2
Application number	US-201414164457-A
Country	US
Kind code	B2
Filing date	Jan 27, 2014
Priority date	Aug 20, 2009
Publication date	Jun 4, 2019
Grant date	Jun 4, 2019

Abstract

A coating composition including an inorganic sol material and an organic colorant is applied to mineral particles and cured at a temperature less than 200 degrees Celsius provides roofing granules with improved luster.

First claim

The invention claimed is:

1. A process for producing roofing granules having a cured coating layer, the process comprising:
(a) providing base particles;
(b) providing a coating composition comprising an inorganic sol material and at least one synthetic organic colorant, the at least one synthetic organic colorant being selected to provide a cured coating layer having an L* of less than 30;
(c) applying the coating composition to the base particles to form a coating layer on the base particles; and
(d) curing the coating layer at a temperature less than 200 degrees Celsius.

2. A process according to claim 1 wherein the at least one synthetic organic colorant comprises a first synthetic organic colorant and a second synthetic organic colorant.

3. A process according to claim 1 wherein the coating composition further comprises at least one inorganic colorant.

4. A process according to claim 1 further comprising preparing the coating composition by:
(a) providing an aqueous suspension of colloidal silica;
(b) mixing an aqueous dispersion of at least one polymeric material with the suspension of colloidal silica; and
(c) mixing a suspension of the at least one synthetic organic colorant with the aqueous suspension of colloidal silica.

5. A process according to claim 4 wherein the coating composition further comprises carbon black.

6. A process according to claim 4 wherein the at least one polymeric material is selected from the group consisting of polyvinyl alcohol, polyethylene oxide, polyacrylic acid, polymethacrylic acid, copolymers including methacrylic acid and alkyl (meth)acrylates, and copolymers including acrylic acid and alkyl (meth)acrylates.

7. A process according to claim 6 wherein the at least one polymeric material comprises polyvinyl alcohol.

8. A process according to claim 1 wherein the inorganic sol is prepared from a sol precursor selected from alkylsilanes, alkoxysilanes, siloxane oligomers, aluminum alkoxides, titanium alkoxides, zirconium alkoxides, aluminum chloride, zirconyl chloride, organozirconates, and organotitanates.

9. A process according to claim 1 further comprising preparing the inorganic sol from a hydrolyzable sol-gel precursor material by acidifying the precursor material to initiate hydrolysis and condensation of the precursor material to form an intermediate material.

10. A process according to claim 9 wherein the sol-gel precursor material is an alkoxysilane selected from the group consisting of tetramethoxysilane, tetraethoxysilane, tetra-n-propoxysilane, tetra-n-butoxysilane, tetrakis(2-methoxyethoxy)silane, methyltriethoxysilane, methyltrimethoxysilane, methyl tri-n-propoxysilane, phenyl triethoxysilane, and vinyl triethoxysilane.

11. A process according to claim 9 wherein the intermediate material is formed in the absence of added alcohol.

12. A process according to claim 9 wherein the intermediate is formed at a temperature from about 20 degrees Celsius to 100 degrees Celsius.

13. A process according to claim 9 further comprising adding base to the intermediate material to form the inorganic sol.

14. A process according to claim 1 wherein the coating composition is applied to the base particles by a fluidized bed method.

15. A process according to claim 1 wherein the coating composition further comprises at least one functional additive selected from the group consisting of biocides, algaecides, fungicides, dyes, fluorescent additives, phosphorescent additives, fragrances, polymeric opacifiers, adhesion promoters, and impact modifiers.

16. A process according to claim 15 wherein the at least one functional additive is selected from the group consisting of leachable metal biocides and nonleachable biocides.

17. A process according to claim 1 , further comprising selecting the at least one synthetic organic colorant to provide roofing granules with a sparkle intensity at 15 degrees of at least 3.

18. A process according to claim 17 , wherein the at least one synthetic organic colorant is selected to provide a sparkle intensity at 15 degrees of at least 5.

19. Roofing granules prepared according to the process of claim 1 .

20. Bituminous roofing materials including roofing granules according to claim 19 .

Assignees

• Certain Teed Corp

Inventors

• Shiao Ming Liang
• Nguyen Van Nhan
• Garre Emmanuel

Classifications

• C23C18/122

  Inorganic polymers, e.g. silanes, polysilazanes, polysiloxanes · CPC title

• Y10T428/2991

  Coated · CPC title

• B01J2/006 Primary

  Coating of the granules without description of the process or the device by which the granules are obtained (to prevent the granules sticking together B01J2/30) · CPC title

• C23C18/1254

  Sol or sol-gel processing · CPC title

• E04D1/20 Primary

  of plastics; {of asphalt;} of fibrous materials · CPC title