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:
Jul. 26, 2011
Filed:
Nov. 14, 2008
Thomas C. Pederson, Rochester Hills, MI (US);
Anil K. Sachdev, Rochester Hills, MI (US);
Thomas C. Pederson, Rochester Hills, MI (US);
Anil K. Sachdev, Rochester Hills, MI (US);
GM Global Technology Operations LLC, Detroit, MI (US);
Abstract
A sand core is prepared for use in defining a surface of a cast metal article. The core is formed of sand particles bonded with a polyurethane resin, preferably a polyol moiety-containing polyurethane resin. An alkali metal hydroxide, and optionally a glycol, is mixed with precursors of the polyurethane before they are mixed with sand particles for molding and curing the core. The hydroxide and glycol may be encapsulated to prevent interference with core molding. The hydroxide and glycol is distributed in the polyurethane binder resin and used to reduce the decomposition temperature of the core binder during casting. This practice is particularly useful in removing core sand from castings of light metal, lower casting temperature metal alloys.