Abstract: An integrated composite-type separator sheet for use in a sealed type lead acid storage battery comprising: (i) at least one pressed fiber layer of a first type consisting essentially of glass fibers having an average diameter of 0.1-2 .mu., and (ii) a pressed fiber layer of a second type consisting essentially of glass fibers having an average diameter of 3-10 .mu., said pressed fiber layer of the second type having a thickness at least equal to the thickness of the pressed fiber layer of the first type.The separator and battery of this invention have the following advantages: good close contact between the separator and the electrode plates maintained for a long time during the use of the battery, and greatly improved performance of the battery and its service life, as compared with conventional batteries.

Abstract: The present invention resides in an envelope type separator for a storage battery and the manufacturing process thereof. The separator sheet is comprised of a first, microporous paper layer made of an inorganic powder material, a synthetic organic fiber material and an organic binder, and a second, coarse paper layer made of a synthetic organic fiber material and an organic binder, but no inorganic powder material, these layers being bound together by heating. The resultant separator sheet of combination paper type is then formed so that the mutually inward surfaces of the coarse paper layer are brought into contact with each other and are made to adhere to each other, preferably at the edges, by thermal fusion, so that the separator sheet is formed into the shape of an envelope process for making an envelope type separator sheet is also described.