Back to results
US 5,856,426 AGranted
Para-oriented aromatic polyamide porous film
AssigneeSumitomo Chemical Company, Limited
InventorsTsutomu Takahashi, Tatsuo Tateno, Yoshifumi Tsujimoto
Life of this patent
Estimating the term…
Loading patent…
Loading patent…
AssigneeSumitomo Chemical Company, Limited
InventorsTsutomu Takahashi, Tatsuo Tateno, Yoshifumi Tsujimoto
Estimating the term…
A para-oriented polyamide porous film comprising a fibril having a diameter of not more than 1.mu., with fibrils planarly arranged as a network or nonwoven fabric and laminated in a layer, the thermal linear expansion coefficient at 200.degree.-300.degree. C. within .+-.50.times.10.sup.-6 /.degree.C. and 30-95% vacant spaces. Also, a battery separator using the porous film. Also, a production process of: (a) forming a film-like material from a solution containing 1-10% of a para-oriented aromatic polyamide having an inherent viscosity of 1.0-2.8 dl/g and 1-10% of a chloride of an alkali metal or an alkali earth metal in a polar amide or polar urea solvent; (b) maintaining the film-like material at not less than 20.degree. C. and not more than -5.degree. C. to deposit the para-oriented aromatic polyamide; and (c) immersing the film-like material in an aqueous or alcoholic solution to elute the sovlent and chloride of the alkali metal or alkali earth metal, then drying to obtain the para-oriented aromatic polyamide porous film. The film has uniformity and fine vacant spaces, which cannot be accomplished by a nonwoven fabric. Characteristics of a para-aramid (e.g., high heat resistance, high rigidity, high strength, etc.) are used.
A para-oriented aromatic polyamide porous film comprising a porous film of a para-oriented aromatic polyamide comprising a fibril having a diameter of not more than 1 .mu.m and having a structure that fibrils are planarly arranged as a network or a nonwoven fabric and laminated as a layer, wherein a thermal linear expansion coefficient at 200.degree. to 300.degree. C. of the film is within .+-.50.times.10.sup.-6 /.degree.C. and having from 30 to 95% of vacant spaces.
A process for producing a para-oriented aromatic polyamide porous film comprising the following steps (a) to (c):
A process for producing a para-oriented aromatic polyamide porous film, comprising the following steps:
Dependencies are inferred from the claim text.