초록 ▼

A composite railroad tie is provided comprising a phosphogypsum filler and a thermoplastic resin. The composite exhibits desirable physical properties for railroad ties. Suitable sources for phospho-gypsum include fertilizer processes involving (a) providing phosphate rock, (b) contacting the phosph

A composite railroad tie is provided comprising a phosphogypsum filler and a thermoplastic resin. The composite exhibits desirable physical properties for railroad ties. Suitable sources for phospho-gypsum include fertilizer processes involving (a) providing phosphate rock, (b) contacting the phosphate rock with sulphuric acid in the presence of water to produce phosphoric acid and a calcium sulphate, (c) separating at least a portion of the phosphoric acid from the calcium sulphate to produce a phosphoric acid product and a calcium sulphate byproduct, (d) drying the calcium sulphate byproduct to remove water therefrom. The calcium sulphate byproduct (phospho-gypsum) is then admixed with a thermoplastic and a functionalized compound to produce a filled thermoplastic composition. The filled thermoplastic composition is then melt processed (for example injection or compression molded) to produce a filled thermoplastic composite railroad tie. The tie is a useful replacement for wood products having several physical property advantages and being suitable made from recycled plastic and waste byproduct filler.

대표청구항 ▼

[ What is claimed is:] [1.] A railroad tie made by melt processing a thermoplastic composition comprising:(a) a thermoplastic resin,(b) an epoxidized oil, and(c) a calcium sulphate composition comprising(i) a calcium sulfate present at a level of from 50 to 99 percent by weight based on the total we

[ What is claimed is:] [1.] A railroad tie made by melt processing a thermoplastic composition comprising:(a) a thermoplastic resin,(b) an epoxidized oil, and(c) a calcium sulphate composition comprising(i) a calcium sulfate present at a level of from 50 to 99 percent by weight based on the total weight of the calcium sulfate composition and(ii) a phosphate present at a level of from 1 to 50 percent by weight based on the total weight of the calcium sulfate composition.