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. 09, 2002
Filed:
Oct. 08, 1999
Daicel Chemical Industries, Ltd., Osaka, JP;
Abstract
The invention provides a method for producing acetylated pyroxylin with safety yet at low cost, using inexpensive water-wetted pyroxylin rather than expensive alcohol-wetted pyroxylin. The acetylated pyroxylin is produced by dehydrating the water-wetted pyroxylin in the presence of a nonalcoholic non-solvent for pyroxylin, and then permitting an acetylating agent to act on the dehydrated pyroxylin. According to the first dehydration process, the water-wetted pyroxylin is dispersed in a dispersing medium comprising a nonalcoholic non-solvent for pyroxylin, and then dehydrated by distillation. According to the second dehydration process, a replacing agent comprising a nonalcoholic non-solvent for pyroxylin is added to the water-wetted pyroxylin, and the wetted pyroxylin is then dehydrated by filtration. With either one of these processes, the water-wetted pyroxylin can be dehydrated with safety.