Molded article having a reduced metal content obtained from a composition comprising a fluorine-containing elastomer

• Main Authors: SOTA, Tomizo, SOGABE, Toshio, MORIKAWA, Tatsuya, KISHINE, Mitsuru, KITAICHI, Masanori, TANAKA, Yoshiyuki
• Format: Patent
• Language: English; French; German
• Published: 26.12.2018
• Subjects: CHEMISTRY; COMPOSITIONS BASED THEREON; MACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVINGCARBON-TO-CARBON UNSATURATED BONDS; METALLURGY; ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP

The present invention concerns a method for preparing a fluorine-containing elastomer, characterized in that any one of the following methods (1) to (8) or by combining two or more thereof are carried out: (1) a metal compound is not blended during emulsion-polymerization of a fluorine-containing monomer, (2) at least one of materials (excluding a gaseous monomer for polymerization) which are used for polymerization of a fluorine-containing monomer, coagulation and drying contains substantially no metal component, (3) emulsion-polymerization of the fluorine-containing elastomer is carried out while maintaining an emulsion in a weak alkaline state, (4) coagulation is carried out after an emulsified dispersion of the fluorine-containing elastomer is filtrated to remove contaminants, (5) coagulation of an emulsified dispersion of the fluorine-containing elastomer is carried out by using an acid containing no metal element, (6) to a fluorine-containing elastomer containing water obtained by coagulation of an emulsified dispersion of the fluorine-containing elastomer is added a non-water-soluble solvent which has compatibility with the fluorine-containing elastomer containing water and contains no metal element to separate the water therefrom, (7) a clean gas is used for drying a fluorine-containing elastomer containing water obtained by coagulation of an emulsified dispersion of the fluorine-containing elastomer or, a coagulated elastomer obtained by adding, to the fluorine-containing elastomer containing water, a non-water-soluble solvent having compatibility therewith and containing no metal element to separate the water therefrom, and (8) a vessel laminated with a fluorine-containing resin film or polyethylene film on its part coming into contact with the coagulated elastomer, a vessel made of a fluorine-containing resin or a vessel made of polyethylene resin is used, and said fluorine-containing elastomer has a metal content of not more than 50 ppm.