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. 09, 1980
Filed:
Oct. 12, 1978
Francisco J Dias, Julich, DE;
Hartmut Luhleich, Duren, DE;
Abstract
A suspension of novolac resin is first produced by dissolving phenol in an queous formaldehyde solution and the addition of an acid catalyst, followed by heating and refluxing. The hot novolac suspension is diluted with water and then converted into a solution by the addition of alkali hydroxide solution bringing the pH value to the range from 10 to 13. While the solution is still hot, particles of some form of carbon are suspended therein by mixing, vibration, or other agitation and the suspension is fed at 60.degree. C. into acidulated water of a temperature of about 50.degree. C., with the flow of acidulated water and suspension adjusted for a volume ratio of, respectively, 8:1. The resin is thereby precipitated on the surface of the particles and the particles are filtered, washed, and dried to produce a material made up of fine grains, evenly coated with binder, which are useful for making graphitic molds for casting metal.