Method for producing binder composition for storage battery device

1. A method for producing a binder composition for a storage battery device, which comprises:

emulsion polymerizing a monomer mixture containing a fluorinated vinyl monomer in the presence of an anionic emulsifying agent (A), an aqueous medium and a radical polymerization initiator to form a latex containing a fluorinated polymer, then

mixing, after emulsion polymerizing, an anionic emulsifying agent (B) with the latex to form the binder composition;

wherein the anionic emulsifying agent (A) is an anionic emulsifying agent having no phenyl group in its molecule, and the emulsion polymerizing is carried out in the absence of an anionic emulsifying agent having a phenyl group,

wherein the content of the anionic emulsifying agent (A) in the monomer mixture during the emulsion polymerizing is from 0.8 to 4.0 parts by mass per 100 parts by mass of the fluorinated polymer produced by the emulsion polymerizing,

the anionic emulsifying agent (B) is an anionic emulsifying agent having a phenyl group in its molecule, and

wherein, after the mixing, the anionic emulsifying agent (B) is present in an amount of 1.7 to 11 parts by mass per 100 parts by mass of the fluorinated polymer in the latex.

2. The method for producing a binder composition for a storage battery device according to claim 1 , wherein during the emulsion polymerizing the content of the anionic emulsifying agent (A) is from 0.1 to 5 parts by mass, per 100 parts by mass of the fluorinated polymer produced by the emulsion polymerizing.

3. The method for producing a binder composition for a storage battery device according to claim 1 , wherein the content of the anionic emulsifying agent (B) in the binder composition after the mixing is from 0.1 to 15 parts by mass, per 100 parts by mass of the fluorinated polymer in the latex.

4. The method for producing a binder composition for a storage battery device according to claim 1 , wherein at least one of the anionic emulsifying agent (A) and the anionic emulsifying agent (B) is an emulsifying agent having a sulfonyl group.

5. The method for producing a binder composition for a storage battery device according to claim 1 , wherein the anionic emulsifying agent (A) is at least one type selected from the group consisting of an alkylsulfate, a sulfosuccinate, a polyoxyalkylene alkyl ether sulfate and a polyoxyalkylene alkenyl ether sulfate.

6. The method for producing a binder composition for a storage battery device according to claim 1 , wherein the anionic emulsifying agent (B) is at least one type selected from the group consisting of an alkylbenzene sulfonate and an alkyl diphenylether disulfonate.

7. The method for producing a binder composition for a storage battery device according to claim 1 , wherein the fluorinated vinyl monomer is at least one type selected from the group consisting of tetrafluoroethylene, vinylidene fluoride and hexafluoropropylene.

8. The method for producing a binder composition for a storage battery device according to claim 1 , wherein the monomer mixture further contains a non-fluorinated vinyl monomer.

9. The method for producing a binder composition for a storage battery device according to claim 1 , wherein the fluorinated vinyl monomer is tetrafluoroethylene, and the monomer mixture further contains propylene.

10. A method for producing an electrode mixture for a storage battery device, which comprises:

producing the binder composition for a storage battery device by the production method as defined in claim 1 and

mixing the binder composition for a storage battery device and an electrode active material to form the electrode mixture.

11. A method for producing an electrode for a storage battery device, which comprises:

producing the electrode mixture for a storage battery device by the production method as defined in claim 10 , and

forming an electrode active material layer on a current collector with the electrode mixture for a storage battery device to form the electrode.

12. The method for producing a binder composition for a storage battery device according to claim 1 , wherein the anionic emulsifying agent (A) is at least one selected from the group consisting of sodium lauryl sulfate, ammonium lauryl sulfate and sodium dialkyl sulfosuccinate.

13. The method for producing a binder composition for a storage battery device according to claim 1 , wherein the anionic emulsifying agent (B) is at least one selected from the group consisting of sodium alkyl diphenyl ether disulfonate and sodium dodecyl benzene sulfonate.

14. The method for producing an electrode mixture for a storage battery device according to claim 10 , further comprising:

mixing the binder composition for a storage battery device with an electrically conductive material.