Abstract: An alkaline secondary battery comprising a negative comprising cadmium, zinc or iron or an oxide or thereof or a hydrogen absorbing alloy, a positive electrode comprising a metal oxide or a metal hydroxide, and a separator, which are all impregnated with an electrolyte comprising an alkaline aqueous solution is disclosed, wherein the separator is made of a polyolefin fiber sheet which has a wicking rate of pure water of at least 10 mm per 2 minutes when one end of the sheet is dipped in pure water at 20.degree. C. and 60% RH. Since the separator is chemically stable and exhibits sufficient hydrophilic properties, the battery retains a high electrode utilization even at a high rate discharging and has a practically sufficient cycle life.

Abstract: A process for producing a polytetrafluoroethylene molded article by isostatic molding is disclosed, the isostatic molding being conducted under a high pressure of from 1,500 to 10,000 kg/cm.sup.2. The resulting molded article is isotropic as regards coefficient of thermal expansion and exhibits improved frictional resistance.

Abstract: A porous film comprising a composition of 10 to 90% by weight of polypropylene and 10 to 90% by weight of polyethylene having an Mw/Mn ratio, as determined by high-temperature gel-permeation chromatography, of 10 or less is disclosed. The porous film has a high tensile modulus, a satisfactory appearance, and a uniform thickness. A battery separator comprising the porous film performs a shut-down function (an increase in resistance) in case of a temperature rise due to an abnormal current.

Abstract: An electrically conductive polymer composite comprising a porous body of polymer A containing interconnected cavities, and polymer B containing an electrically conductive filler and filling the cavities of the porous body. This polymer composite can be made by filling the cavities of the porous body with a liquid monomer, monomer mixture or prepolymer and then polymerizing or cross-linking it to yield polymer B in solid form. The polymer composite has excellent mechanical properties and high electrical conductivity and, therefore, is suitable for use as an electrically conductive material, electromagnetic wave shielding material, heating element and antistatic material.

Abstract: A method of reducing friction losses in aqueous and nonaqueous liquids is disclosed. A certain polymeric material has heretofore been admixed to this end with flowing liquids, such polymer being dissolvable to form a solution. The prior art method is effective for friction loss reduction, but has a drawback in that the polymer is susceptible to scission of its chains under shear stress and hence is unstable in the solution. The invention disclosed is based on the discovery that friction losses in liquids can be reduced with maximum stability by adding to a liquid a predetermined amount of selected organo-polymeric microfibrils which are insoluble but highly dispersible in the liquid. The method of the invention may be applied for instance in the transport of various liquids and crude oils through pipelines and also in the circulation of aqueous and nonaqueous lubricants.

Abstract: A process for preparing permeable membranes which comprises mixing in the molten state two different kinds of thermoplastic synthetic resins which are partly compatible with each other, shaping the molten mixture into a sheet- or film-like melt, passing the film- or sheet-like melt through a heated zone, cooling and solidifying it, the time from the shaping of the molten mixture into the film- or sheet-like melt to its cooling and solidification (melt maintenance time) being adjusted to 10 to 600 seconds, treating the resulting film or sheet with a solvent which is a good solvent for one of the component resins but is a poor solvent for the other to dissolve and remove the soluble resin, and drying the product. In place of the resin to be removed by the solvent, rubbers or oligomers having partial compatibility with the resin which remains undissolved can be used.

Abstract: Synthetic paper comprising a film base material formed from a thermoplastic resin and a filler composed of a large number of fibrous filaments and a pigment and uniformly scattered over the base material, the dispersed filaments and pigment having void spaces therearound, so that the resultant synthetic paper as a whole presents a whitish opague texture similar to Japanese paper, with a large amount of white threadlike patterns all over the base material.

Abstract: A process for preparing permeable membranes which comprises kneading in the molten state two different kinds of thermoplastic synthetic resins which are partly compatible with each other, fabricating the molten mixture into a sheet, film or hollow article, treating the fabricated article with a solvent which is a good solvent for one of the component resins but is a poor solvent for the other to dissolve and remove the former resin, drying the fabricated article, and then stretching it. In place of the resin to be removed by the solvent, rubbers or oligomers having partial compatibility with the resin which remains undissolved can be used.

Abstract: A process for preparing a synthetic wood comprises fusion mixing a thermoplastic resin and a particulate filler, molding the resulting mixture into sheets, monoaxially drawing the sheets, arranging the drawn sheets one upon another and then rapidly heating the thus-arranged drawn sheets to fusion bond them together thereby obtaining the synthetic wood. In one embodiment the sheets may allow a thermoplastic resin film to be inserted between any adjacent two sheets before the heating step, and in another embodiment the sheets may be coated with a thermoplastic resin before or after the drawing step.