(US4816431-A)      Dispersion of raw materials for reaction layers of a gas permeable electrode (I) is prepd. by mixing hydrophobic carbon blacks, PTFE, water and a surfactant.This mixt. is frozen at a rate of 5-50 deg.C/hr. to a temp. at which the surfactant loses at least part of its function, and then the mixt. is thawed out. Pref. the freezing temp. is of -10 to -50 deg.C..    ADVANTAGE -   Process is provided for readily producing a large vol.of a dispersion of uniformly and finely dispersed raw materials for (I).    (4pp9    (US5124018-A)      Preparing raw material powders for a reaction layer of a gas- permeable electrode comprises mixing hydrophilic minute particles (I) coated with ion-exchange resin, PTFE powder and hydrophobic C black powder. (I) comprises hydrophilic C blacks supporting catalysts.    USE/ADVANTAGE -   The raw material powders are used in the mfr. of reaction layers of a gas permeable electrode for use in a fuel cell, a secondary battery or an electrochemical reactor. The material exhibits superior catalytic performance because catalysts contained in (I) are neither liberated nor made to flow, so that the initial catalytic activities are substantially maintained even after a relatively long period of use.    (JP2505446-B2)      Prepn. of the liq. involves mixing hydrophilic carbon black, polyethylene tetrafluoride, water, and surfactant. The mixt. is frozen, then defrosted to prepare the dispersed material liq.    USE/ADVANTAGE -   The liq. is used for fuel cells, secondary cells, electrolytic reactors. Uniformly and finely dispersed material liq. can be obtd.    In an example, hydrophilic carbon black with average dia. of 420 Angstroms, powder of polyethylene tetrafluoride with average dia. of 0.3 microns, water, and triton X-100, as the surfactant, were mixed at ratio of 7:3:1000:100. The mixt. was cooled down to minus 30 deg.C at cooling rate of 20 deg.c/hr., then defrosted at room temp. to obtain liq. contg. the dispersed material with particle size of 2-10 microns. The particle size of the dispersed material was easily controlled by changing the cooling rate. Dispersion of the particle sizes was in the range of 2-10 microns as opposed to the range of 1-100 microns by conventional method without freezing and defrosting the dispersed material liq.