Battery Separator and process for making same

摘要

1,158,705. Reinforcing edges of and seaming non-metallic sheet material; moulding battery separators. MONSANTO CO. 3 Oct., 1966 [22 Oct., 1965], No. 44094/66. Headings B5A and B5K. [Also in Divisions D1 and H1] A battery separator 10 comprises a plurality of acrylic fibres containing at least 80% acrylonitrile and of diameter less than 20Á arranged in a randomly overlapped relationship and densified by heat and pressure into a microporous fibrous felt 12 having an average pore size of less than 60 Á. The fibres can have an average diameter of 3 Á. The separator can be made by hot pressing or calendering a web of density 33À8-169À0 g./sq.m., e.g. at 93À33- 204À44‹ C. at 352-35200 g./cm.2 for 5-60 seconds between caul plates coated with P.T.F.E. Before pressing the web can be impregnated with a resin, e.g. a cross-linked acrylic, polyvinyl chloride or an aqueous solution of a water-soluble phenolic resin. Alternatively the fibres may be bonded directly fibreto-fibre by virtue of the presence of solvent from the spinning process causing them to become thermoplastic during pressing. The web may be self-supporting or it can be secured at its outer periphery to a frame 14 of thermoplastic acidresistant material, e.g. polystyrene, butadienestyrene copolymer, polyacrylates, such as polymethylmethacrylate, and a polyvinyl chloride sheet 0À508 cm. thick. This sheet can be formed with raised ribs 16 by moulding at 21À1-42À2 kg./cm.2 at 93À33-204À440 C. for 5-60 seconds and cooling under a pressure of 21À1-42À2 kg./cm.2. The laminating of the frame 14 to the web can be performed under the same conditions as the moulding above. The web can be planar or it can be pressed into the raised ribs, see Figs. 2 and 3, not shown.