Asahi Kasei Chemicals Corporation

Asahi Kasei Kogyo Kabushiki Kaisha

Hiroshi Sogo

Hiroshi Hatayama

Masahiro Ohashi

Takashi Ikemoto

Masayuki Adachi

Disclosed is a polyolefin microporous membrane including a multilayer film having two or more layers. In this polyolefin microporous membrane, at least one surface layer has a thickness of not less than 0.2 &#x3bc;m but not more than 5 &#x3bc;m and contains inorganic particles, while at least one layer contains a polyethylene and has an air permeability of not less than 50 second/100 cc but not more than 1000 second/100 cc and a puncture strength of not less than 3.0 N/20 &#x3bc;m.

Polyolefin microporous membrane

The present invention provides a polyolefin microporous membrane made of a polyolefin resin and an inorganic particle, and the puncture strength of the microporous membrane is 3 N/20 &#x3bc;m or more and the membrane thickness retention ratio in penetration creep is 16% or more, thereby being excellent in safety and long-term reliability, and a separator for a nonaqueous electrolyte battery, and the like can be provided.

Polyolefin microporous membrane and separator for nonaqueous electrolyte battery

A microporous film, characterized in that it is prepared by a method comprising melting and kneading a polyolefin resin, inorganic particles and a plasticizer, forming the resultant mixture into a sheet, subjecting the rejecting the resultant sheet to a biaxial stretching treatment of a surface magnification of not less than 20 and less than 100 times, and then extracting the plasticizer, it has an inorganic particle content of 20 to 60 mass %, and it exhibits a piercing strength of 3.0 N/20 &#x3bc;m or more.

Microporous polyolefin film and separator for storage cell

The invention relates to a microporous membrane, which is provided with high safety even under a condition that the interior temperature of a battery becomes high, and which has high permeability and high mechanical strength at the same time. The polyolefin microporous membrane is characterized by a membrane thickness of 5 to 50 &#x3bc;m, a void content of 30 to 60%, a gas transmission rate of 40 to 300 sec/100 cc/20 &#x3bc;m, a piercing strength of not less than 2.5 N/20 &#x3bc;m and a break through temperature of not lower than 110&#xb0; C. The separator in accordance with the present invention is used to exhibit high safety under a high temperature condition as well as high permeability, and therefore it is particularly useful as a separator for miniaturized high capacity batteries of a non-aqueous electrolytic solution type.

Polyolefin microporous membrane and method of evaluating the same

A separator for a battery using an organic electrolytic solution, which comprises a microporous film comprising a matrix comprised of a polyethylene and a propylene polymer having a weight average molecular weight of from 10,000 to 1,000,000, the propylene polymer being present in a proportion of from 5 to 45% by weight, based on the total weight of the polyethylene and the propylene polymer, the polyethylene containing a fraction having a molecular weight of not smaller than 1,000,000 in a proportion of at least 10% by weight and a fraction having a molecular weight of not greater than 100,000 in a proportion of at least 5% by weight, and wherein the microporous film has a thickness of from 10 to 500 .mu.m, a porosity of from 40 to 85% and a maximum pore diameter of from 0.05 to 5 .mu.m.

Growing community of inventors

Moriyama, Japan

Hiroshi Sogo