| abstract |
Composite fibers useful for preparing diaphragms are prepared by(a) mixing a PTFE or PTFE copolymer dispersion or powder with a finely divided inorganic material and a fiber forming material,(b) shear heating the resulting mixture to a temperature at which sheared to PTFE or PTFE copolymer becomes flowable without showing signs of decomposition while removing the dispersion medium, if a PTFE or PTFE copolymer dispersion is used,(c) cooling the mixture to below 70° C.,(d) mix shearing the mixture at below 70° C. to form composite fibers. |