Abstract: Positive electrode active material for nonaqueous electrolytic solution secondary batteries is made of a metal oxide. A content of coarse particles, of which particles sizes are 600% or more with respect to an average particle size of the metal oxide, is 1% or less by volume, and a content of high density particles, of which densities are 150% or more with respect to an average density of the metal oxide, is 1000 ppm or less. By using the positive electrode active material, battery characteristics and a manufacturing yield may be improved.

Abstract: A mica tape formed by a paper-making process from a mixture of the mica particles and at least one selected from the group consisting of a short fiber made of a nitrogen-free organic material and a short fiber made of an inorganic material, and an insulated coil by winding the mica tape around a conductive coil and impregnating the mica tape with a solventless thermo-setting resin. The short fiber has an average diameter of 0.1 to 20 .mu.m and an average length of 0.5 to 10 mm.

Abstract: A superconducting coil bas a winding wire portion which is formed by winding a superconducting wire covered with an insulating material around a winding frame composed of such a material that its modulus of longitudinal elasticity is 50 (GPa) or greater, and its thermal contraction rate between a room temperature and a temperature of 77 (K) is 0.35% or above while applying a tensile force thereto, and a bonding material impregnated between the superconducting wires and is then solidified by a heat treatment to reduce a contact surface pressure between the winding wire portion and the winding frame, preventing transition to a normal conductive state.

Abstract: An electrically insulated coil comprising a coil; and a mica tape wound around said coil and containing a resin composition; said resin composition including an epoxy resin, a curing catalyst consisting of an aluminum compound, and a curing accelerator selected from the group consisting of a silane compound having a hydroxyl group and a polysiloxane compound having a hydroxyl group, said curing catalyst being added in an amount of 0.1 to 5% by weight based on said epoxy resin, said curing accelerator being added in an amount of 0.1 to 10% by weight based on said epoxy resin, and said resin composition being cured by heating after said mica tape is wound around said coil.

Abstract: An electrically insulated coil is composed of a coil and a mica tape containing a first resinous composition, wound upon the coil; the resinous composition containing a maleimide compound, an epoxy resin, a curing catalyst consisting of an aluminum compound, and a curing accelerator selected from the group consisting of a silane compound having a hydroxyl group and a polysiloxane compound having a hydroxyl group; the curing catalyst and the curing accelerator each being in an amount of about 0.0001 to 5% by weight based on the total amount of the maleimide compound and the epoxy resin; and the resinous composition being cured by heating after the mica tape is wound around the coil.The electrically insulated coil may further contain a second resinous composition comprising an epoxy resin and an acid anhydride, the second resinous composition impregnating the mica tape after the mica tape is wound around the coil, and being heat-cured together with the first resinous composition.

Abstract: A compound mica sheet is prepared by bonding a mica sheet to a woven fabric through a powdered epoxy resin with curing agent. The mica sheet holds a cured thermosetting resin composition impregnated therein and has an uncured epoxy resin composition including a curing agent impregnated therein. When thermosetting resin is forcedly impregnated, through vacuum/pressure impregnation, into a coil wound with the compound mica sheet which is adapted for use in medium and high voltage electric apparatus, and then cured, an excellent insulated coil is obtained.

Abstract: A method of manufacturing an electrically insulated coil having excellent insulation characteristics and high reliability using a vacuum-pressure impregnation process comprises the step of selectively effectively combining epoxy resins, curing agents and curing accelerators employed as a mica bonding agent and an impregnant.