Method for spray forming high modulus polyurethane structures
AssigneeTSE Industries, Inc.
InventorRobert Michael Raday
Life of this patent
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Abstract
Sprayable polyurethane compositions contain particulate filler in both polyol and isocyanate components for a total content of minimally 30 weight percent of particulate filler and fibrous reinforcement. The isocyanate component is stable with respect to storage, and composite structures prepared therefrom exhibit high modulus and can be used as replacements for unsaturated polyester systems. Resin transfer molding systems employ the same components and produce molded parts with good physical properties.
Claims28
A highly filled multilayer composite structure, prepared by spraying onto a substrate, at least one non-foam polyurethane layer comprising:
- a) an isocyanate component containing minimally about 5 weight percent of a stable particulate filler dispersed therein, the isocyanate component comprising an aromatic isocyanate, modified aromatic isocyanate, or aromatic isocyanate prepolymer, wherein the aromatic isocyanate comprises a toluene diisocyanate, methylene diphenylene diisocyanate, or polymethylene polyphenylene polyisocyanate, and
- b) a polyol component containing minimally about 15 weight percent of a particulate filler dispersed therein,
- wherein the components a) and b) are mixed together and immediately sprayed onto the substrate to form a particulate filler and fiber reinforced layer, wherein fibrous reinforcement is additionally included in the composite structure by introducing chopped fibers into a spray cone which impinges upon the fibrous reinforcement and directs it to the substrate, wherein the total particulate filler content of the layer is minimally 20 weight percent, and wherein the total of particulate filler and fiber reinforcement is greater than 30 weight percent, and
- optionally repeating the spraying to form a multilayer structure, wherein the isocyanate component is substantially free of water and the polyol component is substantially free of water.
A process for the preparation of a non-foam polyurethane composite structure, comprising:
- mixing in a spray head
- a) a substantially water-free isocyanate component containing minimally about 5 weight percent of stable particulate filler dispersed therein, the isocyanate component comprising an aromatic isocyanate, modified aromatic isocyanate, or aromatic isocyanate prepolymer, wherein the aromatic isocyanate comprises a toluene diisocyanate, methylene diphenylene diisocyanate, or polymethylene polyphenylene polyisocyanate, and
- b) a substantially water-free polyol component containing minimally about 15 weight percent of a particulate filler dispersed therein,
- and introducing chopped reinforcing fibers into a spray cone of mixture from the spray head, and spraying the resultant mixture onto a substrate to form a particulate filler and fiber reinforced layer, optionally repeating spraying to form multiple layers, and curing to form a composite structure, wherein the total particulate filler content of a particulate filler and fiber reinforced layer is minimally 20 weight percent, and wherein the total of particulate filler and reinforcing fiber in the layer is greater than 30 weight percent.
In a resin transfer molding process wherein a reactive liquid polymer-forming component is introduced into a mold containing fiber reinforcement, the improvement comprising selecting as said liquid polymer-forming component, a polyurethane system comprising:
- a) a substantially water-free isocyanate component containing minimally about 5 weight percent of a stable particulate filler dispersed therein, the isocyanate component comprising an aromatic isocyanate, modified aromatic isocyanate, or aromatic isocyanate prepolymer, wherein the aromatic isocyanate comprises a toluene diisocyanate, methylene diphenylene diisocyanate, or polymethylene polyphenylene polyisocyanate.
- b) a substantially water-free polyol component containing minimally about 15 weight percent of a particulate filler dispersed therein,
- and wherein the total particulate filler content of the polyurethane system is minimally 20 weight percent.
Dependencies are inferred from the claim text.