Ube Industries, Inc.

Daiken Iki Co., Ltd.

Akira Kawabata

Masayuki Yamada

Takeshige Nakayama

Tomonori Nakayama

Junichi Yamanaka

Kenji Sonoyama

Susumu Takasaki

Shoji Hori

Hiroshi Kurauchi

Satoru Toyoshima

Tetuo Akazawa

Hiroaki Mitsuhashi

Yukio Ushiya

A method for producing an aqueous polyimide precursor solution composition includes reacting a tetracarboxylic dianhydride and a diamine in the presence of an imidazole, using water as a reaction solvent to provide an aqueous polyimide precursor solution composition. The polyamic acid and the imidazole are dissolved in the water. A concentration of the polyamic acid is 5 to 45 wt %, The imidazole is an imidazole having two or more alkyl groups as substituents. An amount of the imidazole is 1.6 moles or more per mole of the tetracarboxylic dianhydride, and a concentration of the imidazole compound based on a sum of the imidazole compound and the water is 9.47 wt % or less. The diamine component includes a diamine having a solubility in water at 25&#xb0; C. of 0.1 g/L or more.

Method for producing aqueous polyimide precursor solution composition

Microbicidal mat and methods of manufacturing and using the same

A porous multi-layer film favorably employable as a separator film for a nonaqueous electric battery comprises at least three united polyolefin layers, in which at least one polyolefin layer is a polyethylene layer and at least one polyolefin layer is a polypropylene layer which is placed in contact with the polyethylene layer. The polyolefin layers are combined to form a united structure with a peel strength of at least 3 g/15 mm and has a pore volume of 30-80%, a maximum pore size of 0.02-2 .mu.m, a shutdown temperature of 135.degree.-140.degree. C., and a thermal durability to maintain the shutdown condition up to at least 180.degree. C.

Porous multi-layer film

Growing community of inventors

Osaka, Japan

Akira Kawabata