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:
Apr. 01, 2008
Filed:
Dec. 16, 2004
Hiroshi Funaki, Chiba, JP;
Koichi Yanase, Chiba, JP;
Hiroki Kamiya, Chiba, JP;
Masao Uehara, Chiba, JP;
Kenichiro Nagatomo, Chiba, JP;
Yasushi Nishimura, Osaka, JP;
Shiro Ohno, Osaka, JP;
Satoru Hirano, Tokyo, JP;
Hiroshi Funaki, Chiba, JP;
Koichi Yanase, Chiba, JP;
Hiroki Kamiya, Chiba, JP;
Masao Uehara, Chiba, JP;
Kenichiro Nagatomo, Chiba, JP;
Yasushi Nishimura, Osaka, JP;
Shiro Ohno, Osaka, JP;
Satoru Hirano, Tokyo, JP;
Asahi Glass Company, Limited, Tokyo, JP;
Sasakura Engineering Co., Ltd., Osaka, JP;
Abstract
An aqueous solution containing a fluorine-containing emulsifier in a low concentration of at least 1 ppm by mass and at most 1% by mass (e.g., coagulation waste water after an emulsion polymerization of a fluoropolymer and/or an aqueous solution obtained by washing with an aqueous solution a waste gas from a drying process and/or a heat treating process of the fluoropolymer) is subjected to vacuum concentration under a pressure of at most 100 kPa and a temperature of the aqueous solution of at most 100° C. by means of a heating tube surface evaporation type concentrator equipped with a heat pump or the like, and the fluorine-containing emulsifier is recovered from a highly concentrated aqueous solution containing the fluorine-containing emulsifier in a higher concentration of at least 5% by mass. According to the present method, the fluorine-containing emulsifier can be recovered with a high yield from a low-concentration liquid such as coagulation waste water of a fluoropolymer.