Patent ID: 6153688
Filing Date: 2000-11-28
Classification: C08L,H01M,Y02E

Abstract:
An aqueous polytetrafluoroethylene dispersion B which is obtained by the following steps:heating an aqueous polytetrafluoroethylene dispersion A, after the preparation thereof, with a polyoxyethylene alkyl ether represented by the formulaRO(CH.sub.2 CH.sub.2 O).sub.n Hwherein R is a saturated or unsaturated hydrocarbon group having 8 to 18 carbon atoms, and n is 5 to 18, wherein said polyoxyethylene alkyl ether has a cloud point of over 45.degree. C. to not higher than 85.degree. C. and an ethylene oxide content of 65 to 70 wt %, to separate the dispersion A into two layers and obtain a concentrated aqueous polytetrafluoroethylene dispersion containing 30 to 65% of polytetrafluoroethylene;recovering the concentrated aqueous polytetrafluoroethylene dispersion; and thereafteroptionally mixing the concentrated aqueous polytetrafluoroethylene dispersion with an amount of a polyoxyethylene alkyl ether represented by the formulaRO(CH.sub.2 CH.sub.2 O).sub.n Hwherein R is a saturated or unsaturated hydrocarbon group having 8 to 18 carbon atoms, and n is 5 to 18 to obtain the aqueous polytetrafluoroethylene dispersion B, wherein said amount of polvoxyethylene alkyl ether results in a concentration of 2 to 10 wt. %, based on the polytetrafluoroethylene, of the polyoxyethylene alkyl ether in the dispersion B.