METHOD OF PREPARING MOLDED POLYTETRAFLUOROETHYLENE WITH LUBRICANT, TAPE SQUEEZE AND DEHYDRATION APPARATUS, AND METHOD FOR DEHYDRATION OF WET SOLID MATERIALS Russian patent published in 2000 - IPC

FIELD: chemical engineering. SUBSTANCE: invention, in particular, relates to preparing polytetrafluoroethylene from wet polytetrafluoroethylene powder containing lubricant homogeneously dispersed therein with lesser number of required operations. Process involves following steps: adding lubricant to aqueous polytetrafluoroethylene dispersion associated with juice coagulation of polytetrafluoroethylene and lubricant and resulting in formation of wet lubricant-containing polytetrafluoroethylene powder; molding thus obtained material to give molded product; and removing lubricant from product. According to another embodiment of invention, wet polytetrafluoroethylene powder is used to fill porous product. In the third version, preparation of wet polytetrafluoroethylene powder is followed by regulation of moisture content therein. After the latter operation, wet powder can also be used to fill porous product. Tape dehydration apparatus contains couple of strip-shaped filter cloth tapes. Tapes are mounted in rotation mode and have mutually opposite surfaces to form a gap between them for passing wet solid materials. Apparatus also has rotation speed and vibration control devices for at least one of the tapes in transverse direction relative to tape. EFFECT: increased homogeneity of lubricant dispersion and excluded drying step with heating. 23 cl, 3 dwg