| 摘要 |
A porous polyfluoroalkylene sheet, preferably of polytetrafluoroethylene, which is suitable for use as a stable low voltage separator or diaphragm in an electrolytic cell, such as one employed for the electrolysis of brine, without being subject to an objectionable voltage increase upon use, is of a thickness in the range of about 0.2 to 2 mm., a porosity in the range of about 70 to 90% and of pore sizes within a range up to about one mm. in diameter, with a pore size distribution such that the pores of a diameter about 0.1 micron (or less) are less than 10% of the total pore volume and the volume of those of about one to ten microns is a substantial part, e.g. 50%, of the total pore volume, and with the ratio of the numbers of such pores in the lower size range to those in the upper range being less than about 30. Limiting the 0.1 micron diameter pores in the microporous sheet helps to prevent the cell from "going high voltage" during operation and the presence of one to ten micron diameter pores improves diaphragm action while still maintaining a low resistance thereof. Also disclosed are: a diaphragm made from a portion of such sheet material; an electrolytic cell including such a diaphragm; a method of electrolyzing brine, utilizing such a cell; and a method for testing of such sheets so as to determine suitability for use thereof as stable low voltage diaphragms in electrolytic cells. |
