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US 4,112,176 AGranted
Ground rubber elastomeric composite useful in surfacings and the like, and methods
AssigneeU.S. Rubber Reclaiming Co., Inc.
InventorAllen R. Bailey
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AssigneeU.S. Rubber Reclaiming Co., Inc.
InventorAllen R. Bailey
Estimating the term…
There is provided a polyurethane ground rubber composite and a new method for formation and preparation thereof. The composite is suitable for use in laminated and other surfacing or as a surfacing and has excellent flexibility, resiliency, weatherability, and elastomeric qualities; and comprises particulate vulcanized rubber substantially coated on each particle with about 3 to about 8 microns, and in some instances about 3 to about 10 microns, of a cross-linked binder derived from an essentially solvent-free polymeric isocyanate prepolymer having a number average molecular weight of 800-4000, the cross-linking of the isocyanate prepolymer being accomplished by controlled reaction with water using an equivalent ratio of NCO/OH of 0.14/1 to 0.83/1 to form urea and buiret linkages, and providing a void content of 25-60 volume percent, so that the carbon dioxide generated by the water/isocyanate reaction can readily diffuse through the film and so that the vented carbon dioxide does not cause foaming of the composite; and methods of controlling the forming of the composite, the layering of the composite, and/or mixing it in situ.
A flexible resilient elastomeric composite composed of vulcanized rubber particles substantially coated and bonded with a cross-linked non-foamed binder consisting essentially of a solvent-free polymeric isocyanate prepolymer cross-linked by urea and biuret linkages and having an excess NCO content of 3-10% and a number average molecular weight between 800 and 4000, said cross-linking of the isocyanate prepolymer being accomplished by the controlled reaction fo prepolymer components in an equivalent ratio NCO/OH of 0.14/1 to 0.83/1;
A flexible, resilient, elastomeric composite having a void content within the range of from 25-60% comprising 60-95 weight percent vulcanized rubber particles partially or wholly coated and bonded together by 5-40 weight percent of a cross-linking non-foamed binder consisting essentially of a solvent-free polymeric isocyanate prepolymer having urea and biuret cross-linkages;
A method of forming a flexible resilient and elastomeric composite which comprises substantially coating vulcanized rubber particles to a thickness of about 3 microns to about 10 microns;
The method of forming and spreading a layer of composite which comprises mixing 60-95 weight percent of crumb rubber with 5-40 weight percent of a cross-linking binder derived from an essentially solvent-free polymeric isocyanate prepolymer having a viscosity of 25.degree. C. of 1,000-12,000 cps. and containing 3-10% excess NCO, spreading the layer in situ and curing said binder by absorption of atmospheric moisture by said prepolymer to form urea and biuret crosslinkages at an NCO/HO ratio of 0.14/1 to 0.83/1.
A method of forming a surfacing which comprises applying on a base a layer of composite comprising 60-95 weight percent of crumb rubber with 5-40 weight percent cross-linking binder consisting essentially of a solvent-free polymeric isocyanate prepolymer having a viscosity at 25.degree. C. of 1,000-12,000 cps. and containing 3-10% excess NCO, cross-linking said isocyanate prepolymer by the reaction with water, the ratio of NCO/OH being 0.14/1 to 0.83/being controlled to form substantially only urea and biuret linkages, and then sealing said exposed composite layer with a polymeric elastomeric coating.
Dependencies are inferred from the claim text.