| 摘要 |
A film for use in dry batteries consists of an alkyl cellulose or vinyl polymer one or both surfaces of which have been rendered insoluble. Alternatively the soluble film may be backed by an insoluble film, a film of alkyl cellulose ether such as methyl cellulose, for example, being backed by a film of regenerated cellulose. A methyl cellulose film may be made insoluble by the addition of polybasic acids, aliphatic or aromatic carboxylic acids or phenol carboxylic acids or by means of citric, phthalic, tartaric and malic acids, or tannic acids such as gallic or digallic acid. A film made from soluble methyl cellulose may be prepared by treating one surface with a tannic acid solution which may be poured, sprayed or wiped on the surface. An insoluble diaphragm may be prepared from a methyl cellulose solution containing tannic or citric acid. Substances other than methyl cellulose may be used such as hydroxyethyl cellulose, salts of the cellulose ethers of glycollic acid such as sodium carboxymethyl cellulose, polyvinyl alcohol, polyvinyl partial acetals or partially hydrolyzed polyvinyl acetate and they may be rendered insoluble by treatment with aldehydes such as glyoxal and formaldehyde, aldehyde resins such as phenol formaldehyde, amide condensation products such as urea, and isocyanates. Films of sodium carboxymethyl cellulose and polyvinyl alcohol may be rendered insoluble by heat. |
