Method for producing porous film

Patent metadata

Field	Value
Publication number	US-10047208-B2
Application number	US-201515529823-A
Country	US
Kind code	B2
Filing date	Nov 20, 2015
Priority date	Nov 27, 2014
Publication date	Aug 14, 2018
Grant date	Aug 14, 2018

Abstract

A method for producing a porous film having a water content percentage of less than 1000 ppm, the method including the steps of: (1) obtaining a porous film (A) having a water content percentage of not less than 1000 ppm; (2) obtaining a package by causing the obtained porous film (A) and a drying agent to be contained in a water vapor barrier packaging container and sealing the water vapor barrier packaging container; and (3) storing the obtained package.

First claim

The invention claimed is:

1. A method for producing a porous film having a water content percentage of less than 1000 ppm,
said method comprising the steps of:
(1) obtaining a porous film (A) having a water content percentage of not less than 1000 ppm;
(2) obtaining a package by causing the obtained porous film (A) and a drying agent to be contained in a water vapor barrier packaging container and sealing the water vapor barrier packaging container; and
(3) storing the obtained package.

2. The method as set forth in claim 1 , wherein the water vapor barrier packaging container has a water vapor transmittance of 0.1 g/m 2 /24 hr to 5 g/m 2 /24 hr at a temperature of 40° C. and a humidity of 90% RH.

3. The method as set forth in claim 1 , wherein the drying agent is contained in the water vapor barrier packaging container in an amount of not less than X mass % with respect to a mass of the porous film (A), the X being calculated based on the following equation (I):
X=Y /( a× 100)  (I)

where a represents an amount of moisture absorption (g) per 100 g of the drying agent at a temperature of 24° C. and a humidity of 10%, and Y represents a water content percentage (ppm) of the porous film (A).

4. The method as set forth in claim 1 , wherein the porous film is a nonaqueous secondary battery separator.

Assignees

• Sumitomo Chemical Co

Inventors

• Yoneyama Satoshi
• Yashiki Daizaburo

Classifications

• H01M50/443

  Particulate material · CPC title

• C08J2401/08

  Cellulose derivatives · CPC title

• C08J2323/06

  Polyethene · CPC title

• H01M10/0525

  Rocking-chair batteries, i.e. batteries with lithium insertion or intercalation in both electrodes; Lithium-ion batteries · CPC title

• H01M4/13

  Electrodes for accumulators with non-aqueous electrolyte, e.g. for lithium-accumulators; Processes of manufacture thereof · CPC title