The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Sep. 01, 1998
Filed:
Apr. 21, 1997
John C Bayer, Folsom, LA (US);
Demer Corporation, Covington, LA (US);
Abstract
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.