Highly-filled polyurethane composites with fiber reinforcement
Composite panels and methods of preparation are described herein. In some embodiments, the composite panel can include a first fiber reinforcement, a polyurethane composite having a first surface and a second surface opposite the first surface, wherein the first surface is in contact with the first fiber reinforcement; and a cementitious material adjacent the first fiber reinforce-opposite the polyurethane composite. The polyurethane composite can be formed from (i) one or more isocyanates selected from the group consisting of diisocyanates, polyisocyanates, and mixtures thereof, (ii) one or more polyols, and (iii) a particulate filler. The fiber reinforcement can be formed from a woven or non-woven material, such as glass fibers. The composite panel can further include a material, such as a second fiber reinforcement and a cementitious layer, in contact with the second surface of the polyurethane composite. Articles comprising the composite panels are also disclosed.
1. A method of manufacturing a composite panel comprising:
mixing (i) one or more isocyanates selected from the group consisting of diisocyanates, polyisocyanates, and mixtures thereof, (ii) one or more polyols, and (iii) from 40% to 90% by weight, based on the total weight of a polyurethane composite, of a particulate filler to form a mixture;
allowing the one or more isocyanates and the one or more polyols to react in the presence of the particulate filler to form a polyurethane composite having a first surface and a second surface opposite the first surface;
applying a first fiber reinforcement to the first surface of the polyurethane composite, wherein the first fiber reinforcement comprises a glass fiber having a basis weight of from 0.5 g/ft 2 to 10 g/ft 2 ;
applying a cementitious slurry comprising a cement to the first fiber reinforcement; and
allowing the cementitious slurry to cure to form the composite panel,
wherein the cementitious layer provides a wettable bonding surface to the composite panel, and the polyurethane composite is a barrier to water absorbed by the cementitious layer that prevents water from passing through the polyurethane composite.
2. The method of claim 1 , further comprising applying a material comprising a cementitious layer, a paper sheet, a metal sheet, a polymeric layer, or a combination thereof to the second surface of the polyurethane composite.
3. The method of claim 1 , further comprising applying a second fiber reinforcement to the second surface of the polyurethane composite.
4. The method of claim 1 , wherein the polyurethane composite is formed in a mold.
5. The method of claim 1 , wherein the one or more isocyanates, the one or more polyols, and the particulate filler are mixed and the mixture is fed to a mold; the first fiber reinforcement is applied to the mixture in the mold; and the one or more isocyanates and the one or more polyols react in the presence of the particulate filler in the mold to form the polyurethane composite, wherein at least a portion of the first fiber reinforcement is embedded in the polyurethane composite.
6. The method of claim 1 , wherein the first fiber reinforcement is applied to a mold; the one or more isocyanates, the one or more polyols, and the particulate filler are mixed and the mixture is fed to the first fiber reinforcement in the mold; and the one or more isocyanates and the one or more polyols react in the presence of the particulate filler in the mold to form the polyurethane composite, wherein at least a portion of the first fiber reinforcement is embedded in the polyurethane composite.
7. The method of claim 1 , wherein the cementitious slurry is applied to the first fiber reinforcement prior to applying the first fiber reinforcement to the polyurethane composite.
8. The method of claim 1 , further comprising applying a liquid to the first surface of the polyurethane composite, to activate the cementitious slurry, wherein the liquid has a pH of 6.5 or greater and optionally comprises an activator.
9. The method of claim 1 , wherein the first fiber reinforcement is applied to the polyurethane composite after the polyurethane composite has been cured.
10. The method of claim 1 , wherein the first fiber reinforcement is applied to the polyurethane composite before it has completely cured such that at least a portion of the first fiber reinforcement becomes embedded in the polyurethane composite.
11. The method of claim 1 , further comprising applying an adhesive to the first fiber reinforcement prior to applying the cementitious slurry.
12. The method of claim 11 , wherein the adhesive is applied by spray coating, curtain coating, brushing, roller coating, dip coating, spin coating, or flow coating.
13. The method of claim 1 , wherein the cementitious slurry is applied by roller coating, dip coating, brushing, with a trowel, or spraying.
14. The method of claim 1 , wherein the particulate filler comprises fly ash.
15. The method of claim 1 , wherein the polyurethane composite has a thickness of 0.125 inches to 3 inches.
16. The method of claim 1 , wherein the cementitious slurry forms a cementitious layer adjacent to the first fiber reinforcement opposite the polyurethane composite, the cementitious layer having a thickness of 0.005 inch to 0.25 inch.
17. The method of claim 16 , wherein the cementitious layer comprises 50% or more of a rapid set cement or Portland cement.
18. The method of claim 1 , wherein the polyurethane composite has a density of from 2 lb/ft 3 to 60 lb/ft 3 .