Claims
- 1. Separators placed between the alternating positive and negative plates in the cells of a lead storage battery, characterized by each separator comprising a dried porous membrane composed of acrylonitrile polymer walls separating predominantly interconnecting small-size pores, which membrane comprises surface layers integrated with a support layer to form a single continuous acrylonitrile polymer phase, at least one of the surface layers having pores of from 0.001 to 0.05 micron in average size, the support layer having pores of a larger average size than the pores in the surface layer or layers, and said membrane having a porosity of from 20% to 70% by volume and a fragility of below 30.
- 2. Separators according to claim 1 wherein each of the two surface layers has pores of from 0.001 to 0.05 micron in average size and a thickness of from 0.1 to 20 microns.
- 3. Separators according to claim 1 wherein one of the two surface layers has pores of from 0.001 to 0.05 micron in average size and a thickness of from 0.1 micron to 1/2 of the thickness of the membrane.
- 4. Separators according to claim 1 further characterized by said dried acrylonitrile polymer membrane containing from 0.1 to 10% by weight of at least one substance selected from the group consisting of a petroleum oil, a vegetable oil, a silicone oil and a wax.
- 5. Separators according to claim 1 further characterized by said acrylonitrile polymer containing a sulfonic acid group or a sulfonate group in an amount of from 0.05% to 2% by weight in terms of the weight of a sulfonic acid group.
Priority Claims (1)
Number |
Date |
Country |
Kind |
51/106613 |
Sep 1976 |
JPX |
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Parent Case Info
This is a division of Ser. No. 831,017, filed Sept. 6, 1977, now pending.
US Referenced Citations (6)
Divisions (1)
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Number |
Date |
Country |
Parent |
831017 |
Sep 1977 |
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