Binder resin for electrode of nonaqueous electrolyte secondary battery, slurry composition, electrode for nonaqueous electrolyte secondary battery, and nonaqueous electrolyte secondary battery

1. A halogen element-free binder resin for an electrode of a nonaqueous electrolyte secondary battery,

wherein the halogen element-free binder resin satisfies the following formula (1) . . . ,

I S ≧30  (1)

wherein I s indicates the sum of scattering intensities observed in the particle diameter range of 1 to 100 nm, when the halogen element-free binder resin is dissolved in an organic solvent to form a solution having a concentration of 5 mass % and particle size distribution is measured at 25° C. by a dynamic light scattering method.

2. The halogen element-free binder resin according to claim 1 ,

wherein in a program of measuring shear rate starting from 0.03 sec −1 , measuring the shear rate until 100 sec −1 along with transfer to a high shear rate, and again measuring the shear rate until 0.03 sec −1 along with transfer to a low shear rate,

when a slurry composition obtained by mixing 100 parts by mass of an active material, 5 parts by mass of a conduction aid and 2 parts by mass of the binder resin with 40 parts by mass of the organic solvent by means of a rotation/revolution stirrer is measured for rheology at 25° C., the binder resin satisfies the following formula (2) and at the same time, dissolves in the organic solvent:

η 0.1 /η 18 ≦20  (2)

wherein η 0.1 indicates a viscosity at a shear rate of 0.1 sec −1 when viscoelasticity is measured while changing the shear rate from 100 sec −1 to 0.03 sec −1 , and η 80 indicates a viscosity at a shear rate of 80 sec −1 when the viscoelasticity is measured while changing the shear rate from 100 sec −1 to 0.03 sec −1 .

3. The halogen element-free binder resin according to claim 1 , wherein the binder resin contains a polymer having a vinyl cyanide monomer unit.

4. A slurry composition of an electrode of a nonaqueous electrolyte secondary battery, comprising the halogen element-free binder resin according to claim 1 , an active material and the organic solvent.

5. An electrode of a nonaqueous electrolyte secondary battery, comprising a current collector and an electrode mixture layer provided on the current collector,

wherein the electrode mixture layer comprises the halogen element-free binder resin according to claim 1 and an active material.

6. An electrode of a nonaqueous electrolyte secondary battery, comprising a current collector and an electrode mixture layer provided on the current collector,

wherein the electrode mixture layer is obtained by coating the slurry composition according to claim 4 on the current collector and drying the coating.

7. A nonaqueous electrolyte secondary battery, comprising the electrode according to claim 5 .

8. A binder resin composition of an electrode of a nonaqueous electrolyte battery, comprising the halogen element-free binder resin according to claim 1 wherein the halogen element-free binder resin comprises: a polymer (A) having a vinyl cyanide monomer (a1) unit as the main component; and a polymer (B) containing a phosphoric acid-containing monomer (b1) unit.

9. The binder resin composition according to claim 8 , wherein the content of the phosphoric acid-containing monomer (b1) unit is from 0.01 to 0.5 mol/kg based on the binder resin composition.

10. A slurry composition of an electrode of a nonaqueous electrolyte battery, comprising the binder resin composition according to claim 8 , an active material and the organic solvent.

11. An electrode of a nonaqueous electrolyte battery, comprising an electrode mixture layer containing the binder resin composition according to claim 8 , an active material, and a current collector.

12. A nonaqueous electrolyte battery, comprising the electrode according to claim 11 .

13. A slurry composition of an electrode of a nonaqueous electrolyte battery, comprising the binder resin composition according to claim 9 , an active material and the organic solvent.

14. An electrode of a nonaqueous electrolyte battery, comprising an electrode mixture layer containing the binder resin composition to claim 9 , an active material, and a current collector.

15. A nonaqueous electrolyte battery, comprising the electrode according to claim 14 .

16. The halogen element-free binder resin according to claim 1 , wherein the halogen element-free binder resin comprises:

50 mass % or more of a polymer (A) containing a vinyl cyanide monomer (a1) unit as a main component; and

a polymer (B) containing a phosphoric acid-containing monomer (b1) unit.

17. The halogen element-free binder resin according to claim 1 , wherein the vinyl cyanide monomer (a1) unit is selected from the group consisting of acrylonitrile, methacrylonitrile, α-cyanoacrylate, dicyanovinylidene and fumaronitrile.

18. The halogen element-free binder resin according to claim 16 , wherein the weight average molecular weight (Mw) of the polymer (A) is 5,000 to 50,000,000.

19. The halogen element-free binder resin according to claim 1 , wherein the content of the phosphoric acid group-containing monomer (b1) unit is from 0.01 to 0.5 mol/kg based on the binder resin composition.

20. The halogen element-free binder resin according to claim 16 , wherein the vinyl cyanide monomer (a1) unit includes the phosphoric acid group-containing (meth)acrylate selected from the group consisting of 2-(meth)acryloyloxyethyl acid phosphate, 2-(meth)acryloyloxyethyl acid phosphate.monoethanolamine salt, diphenyl((meth)acryloyloxyethyl) phosphate, (meth)acryloyloxypropyl acid phosphate, 3-chloro-2-acid.phosphoxypropyl (meth)acrylate, acid.phosphoxypolyoxyethylene glycol mono(meth)acrylate, and acid.phosphoxypolyoxypropylene glycol (meth)acrylate.