| 摘要 |
901,579. Permeable diaphragm material. OLDHAM & SON Ltd. March 23, 1960, No. 10344/60. Addition to 843,452. Class 140. [Also in Group XXXVI] Permeable diaphragm material having pores of predetermined size comprises a base diaphragm material of sintered thermoplastic powder having formed thereon and extending over at least one face thereof a continuous lacelike network of a thermoplastic, the network comprising abutting finely-divided particles of the thermoplastic fused together at their points of contact and adhering to the base diaphragm material, and the pores of predetermined size being constituted by the interstices of the continuous lace-like network. The permeable diaphragm material may be an electric storage battery separator material, the base diaphragm material being a base separator material, which may be comprised of sintered polyvinyl chloride powder having an average particle diameter of about 10 microns and the lace-like network may be comprised by a mixture of finely-divided particles of polyvinyl chloride, the predominant constituent having an average particle diameter size of ¢ to 1 micron and the other constituent having an average particle diameter size of 10 microns. One face of the base separator material may be ribbed and the network extends over the ribbed face. The size of the pores of the base diaphragm are reduced to a predetermined extent by applying to the face of the material finely-divided particles of a thermoplastic so as to form a layer of abutting particles on the face and then fusing, e.g. at about 150‹ C., the particles at their points of contact to form the continuous lace-like network. The particles may be brushed over the face of the base diaphragm material so that the particles penetrate into the existing pores of the material. The base diaphragm material may be advanced in the form of a continuous web past a falling curtain of particles and the layer of particles levelled off to effect a uniform distribution over the face of the material prior to brushing in. The base separator material may be prepared by sintering together, at about 250‹ C., particles of polyvinyl chloride powder having an average particle diameter of about 10 microns. Particles of polyethylene, polystyrene or acrylic resin may also be used. As shown, particles from vibrating hopper 4 fall on conveyer belt 1 and are consolidated to a required thickness and shape by ribbed roller 5, which may be heated, prior to sintering in oven 6 and subsequent cooling by blower 7. A curtain of particles from vibrating hopper 8 forms a coating on the sintered base material which is levelled off by stationary brush 9 which also removes surplus particles. Rotating brush 10 forces the particles into the pores of the base material prior to sintering in oven 11, cooling by blower 12 and passage through cutters 13. |
