Ppg Industries, Inc.

Ppg Industries Ohio, Inc.

Robert C Wang

Thomas G Krivak

James L Boyer

Harold E Swift

Richard A Schwarz

Laurence E Jones

Raymond R Ondeck

Richard W Pekala

Very thin microporous material comprises a matrix of substantially linear polyolefin, finely divided substantially water-insoluble filler particles distributed throughout the matrix, and a network of interconnecting pores communicating substantially throughout said microporous material. The very thin microporous material can be produced by the blown film process. The material is used as a separator in a battery.

Very thin microporous material

Amorphous precipitated silica which may be used to form battery separators of very low specific resistance is characterized by (a) a CTAB surface area in the range of from 140 to 185 m.sup.2 /g; (b) a DBP oil absorption in the range of from 210 to 310 cm.sup.3 /100 g; (c) a mean ultimate particle size in the range of from 10 to 18 nm; (d) a total intruded volume in the range of from 2.6 to 4 cm.sup.3 /g; and (e) an intruded volume in the range of from 0.9 to 2 cm.sup.3 /g for pores having diameters in the range of from 20 to 100 nm.

Amorphous precipitated silica

Particles comprising particulate amorphous precipitated silica in association with from 5 to 10 percent by weight sodium sulfate and less than 10 percent by weight water, wherein the percentages are based on the weight of the silica, the sodium sulfate, and the water, which particles have a BET surface area of from 100 to 300 m.sup.2 /g, a total intruded volume from 1.8 to 3.6 cm.sup.3 /g, and a DBP oil absorption of from 180 to 320 cm.sup.3 /100 g, may be employed in microporous battery separators to introduce all or a portion of the desired sodium sulfate to the battery electrolyte. Moreover the enhanced amount of sodium sulfate enhances silica characteristics and battery separator production.

Precipitated silica having high sodium sulfate content

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Wexford, PA, United States of America

Robert C Wang