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:
Jun. 15, 1999
Filed:
May. 01, 1997
Richard M Berger, Midlothian, VA (US);
Filtrona International Limited, London, GB;
Abstract
A porous element particularly for use as a tobacco smoke filter plug in association with a cigarette or the like wherein the matrix comprises a multiplicity of biodegradable polyvinyl alcohol fibers bonded together at their points of contact to define a tortuous interstitial path for the passage of smoke. Because of the hygroscopic nature of polyvinyl alcohol, commercial production of such products require careful control of the moisture content of the polyvinyl alcohol fiber starting material, usually pre-drying the same to a residual moisture content of 7% by weight or less, and treatment of the low moisture fibrous mass by superheated steam to add about 2.5 to 5% moisture to a final moisture content of about 2.5 to 10%. The steam renders the fiber surface adhesive and, thus, bondable, and also lubricates the gathered fibers to improve processability.