| 摘要 |
1,199,717. Sheet casting. W. R. GRACE & CO. 10 March, 1969 [12 March, 19681, No. 12600/69. Heading B5A. [Also in Divisions B1-B2 and C3] A process for continuously making microporous battery separators comprises (a) preparing a solution of a thermosetting resin in a volatile medium, (b) mixing said solution with a curing agent, (c) feeding the mixture into the space between two spaced endless synchronously moving pressure belts, (d) solidifying the mixture while it is pressed between the moving belts to prevent evaporation of the volatiles contained in the resin mixture to gel the resin and to form a continuous sheet with the volatiles finely dispersed therein, (e) evaporating the volatiles from the sheet after it has gelled, and curing the resin; and (f) slitting the sheet to form battery separators of the desired size. The resin solution also contains thermoplastic resins and/or polymer lattices. Resin precursors, solvents and fillers are prepared in mixing tanks A 1 , A 2 and are fed to a series of cascade reactors B 1 , B 2 , B 3 from which the mixture passes to a cooler C, a tank S and a mixing head M which receives the curing agent from a tank CA; the mixer M supplied the resin to the slope L l of the lower belt L. With water as solvent suitable resins are the condensation products of formaldehyde or other aldehydes with hydroxy benzenes and examples of strong acid curing agents are given. The belts are preferably made of stainless-steel but can be of a polymeric fluorocarbon material. The belts U, L may be heated, e.g. by saturated steam or hot liquid, to increase the rate of gelling. A fibrous web FM may be fed to the space between the belts, one or both of which may be grooved. The sheet may be provided with ribs by extruding thermoplastic strips on to one side. The sheet leaves the belts and passes through a washing station W, a drying station D, slitting apparatus SL, a curing oven CUR, rib extrusion apparatus RE and a cutter CUR. |
