Acqueous dispersion of vinylidene flouride polymer and preparation process thereof

Abstract

Aqueous dispersion of a vinylidene fluoride (VdF) polymer which comprises a VdF polymer having a particle size of not more than 200 nm and contains 30 to 50% by weight of solids and not more than 1% by weight of a fluorine-containing surfactant on the basis of water. This aqueous dispersion is prepared by emulsion-polymerizing VdF monomer or a monomer mixture containing VdF under coexistence of not more than 1% by weight of the fluorine-containing surfactant and 0.001 to 0.1% by weight of a nonionic non-fluorine-containing surfactant on the basis of water, and is suitably used for paints.

1 . An aqueous dispersion of a vinylidene fluoride polymer, which comprises a vinylidene fluoride polymer having an average particle size of not more than 320.1 nm, wherein a solid content is from 30 to 50% by weight, and a content of a fluorine-containing surfactant is not more than 1% by weight on the basis of water.  
     
     
         2 . The aqueous dispersion of  claim 1 , wherein the fluorine-containing surfactant is at least one member selected from the group consisting of a fluorine-containing carboxylic acid represented by the formula: X(CF 2 ) n COOH and Y(CH 2 CF 2 ) m COOH where n is an integer of 6 to 20, X is F or H, m is an integer of 6 to 13, and Y is F or Cl, an alkali metal salt thereof, an ammonium salt thereof, an amine salt thereof and a quaternary ammonium salt thereof.  
     
     
         3 . The aqueous dispersion of  claim 1 , wherein the fluorine-containing surfactant is an ammonium salt of perfluorooctanoic acid.  
     
     
         4 . An aqueous dispersion of a vinylidene fluoride polymer, which comprises a vinylidene fluoride polymer having an average particle size of not more than 196.3 nm, wherein a solid content is from 30 to 50% by weight, and a content of a fluorine-containing surfactant is not more than 2% by weight on the basis of water.  
     
     
         5 . The aqueous dispersion of  claim 4 , wherein the fluorine-containing surfactant is at least one member selected from the group consisting of a fluorine-containing carboxylic acid represented by the formula: X(CF 2 ) n COOH and Y(CH 2 CF 2 ) m COOH where n is an integer of 6 to 20, X is F or H, m is an integer of 6 to 13, and Y is F or Cl, an alkali metal salt thereof, an ammonium salt thereof, an amine salt thereof and a quaternary ammonium salt thereof.  
     
     
         6 . The aqueous dispersion of  claim 4 , wherein the fluorine-containing surfactant is an ammonium salt of perfluorooctanoic acid.  
     
     
         7 . An aqueous dispersion of a vinylidene fluoride polymer, which consists essentially of a vinylidene fluoride polymer having an average particle size of not more than 200 nm and a surfactant, wherein a solid content is from 30 to 50% by weight, a content of the surfactant is not more than 1% by weight on the basis of water, and the surfactant consists essentially of at least one of a fluorine-containing surfactant.  
     
     
         8 . The aqueous dispersion of  claim 7 , wherein the fluorine-containing surfactant is at least one member selected from the group consisting of a fluorine-containing carboxylic acid represented by the formula: X(CF 2 ) n COOH and Y(CH 2 CF 2 ) m COOH where n is an integer of 6 to 20, X is F or H, m is an integer of 6 to 13, and Y is F or Cl, an alkali metal salt thereof, an ammonium salt thereof, an amine salt thereof and a quaternary ammonium salt thereof.  
     
     
         9 . The aqueous dispersion of  claim 7 , wherein the fluorine-containing surfactant is an ammonium salt of perfluorooctanoic acid.  
     
     
         10 . A method for preparing a paint composition, which consists essentially of blending a coloring agent with an aqueous dispersion of a vinylidene fluoride polymer, which comprises a vinylidene fluoride polymer having an average particle size of not more than 200 nm and a surfactant, wherein a solid content is from 30 to 50% by weight, a content of the surfactant is not more than 1% by weight on the basis of water, and the surfactant consists essentially of at least one of a fluorine-containing surfactant.  
     
     
         11 . The method of  claim 10 , wherein the fluorine-containing surfactant is at least one member selected from the group consisting of a fluorine-containing carboxylic acid represented by the formula: X(CF 2 ) n COOH and Y(CH 2 CF 2 ) m COOH where n is an integer of 6 to 20, X is F or H, m is an integer of 6 to 13, and Y is F or Cl, an alkali metal salt thereof, an ammonium salt thereof, an amine salt thereof and a quaternary ammonium salt thereof.  
     
     
         12 . The method of  claim 10 , wherein the fluorine-containing surfactant is an ammonium salt of perfluorooctanoic acid.