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:
May. 14, 1985
Filed:
May. 18, 1982
Norman B Rainer, Richmond, VA (US);
Charles S McClung, Prince George, VA (US);
Philip Morris Incorporated, New York, NY (US);
Abstract
Non-combustible carbonized cigarette filters are manufactured wherein porous cellulosic material is contacted with a film-forming aqueous solution of an inorganic salt selected from the group consisting of alkali metal and ammonium silicates, carbonates, hydrophosphites, diphosphites, phosphites, hypophosphates, orthophosphates, diphosphates, triphosphates, polymetaphosphates, peroxymonophosphates, peroxydiphosphates, orthoborates, metaborates, tetraborates and mixtures thereof so that the cellulosic material contains at least about 1%, preferably from about 2% to about 6%, of the salt on a dry weight basis and then pyrolyzing the treated cellulosic material in an inert atmosphere at a temperature of at least about 700.degree. C. to about 900.degree. C., under conditions such that at least about 15%, preferably from about 20% to about 40% of the initial weight of the cellulosic material remains after pyrolysis.