Binder composition for non-aqueous secondary battery porous membrane, slurry composition for non-aqueous secondary battery porous membrane, porous membrane for non-aqueous secondary battery, and non-aqueous secondary battery and production method therefor
Provided is a binder composition for a non-aqueous secondary battery porous membrane capable of forming a porous membrane having improved adhesiveness in electrolyte solution, heat shrinkage resistance in electrolyte solution, and blocking resistance. The binder composition for a non-aqueous secondary battery porous membrane contains a particulate polymer A and a particulate polymer B having a larger volume-average particle diameter than the particulate polymer A. The particulate polymer A includes a (meth)acrylic acid alkyl ester monomer unit in a proportion of not less than 50 mass % and not more than 90 mass %. The particulate polymer B has a core-shell structure and includes a nitrile group-containing monomer unit in a core portion of the core-shell structure.
1. A binder composition for a non-aqueous secondary battery porous membrane comprising:
a particulate polymer A; and
a particulate polymer B having a larger volume-average particle diameter than the particulate polymer A, wherein
the particulate polymer A includes a (meth)acrylic acid alkyl ester monomer unit,
a percentage content of the (meth)acrylic acid alkyl ester monomer unit when the amount of all monomer units included in the particulate polymer A is taken to be 100 mass % is 50 mass % or more and 90 mass % or less,
the particulate polymer B has a core-shell structure and includes a nitrile group-containing monomer unit in a core portion of the core-shell structure,
the particulate polymer A has a volume-average particle diameter of not less than 50 nm and not more than 250 nm,
the particulate polymer B further includes an acidic group-containing monomer unit in the core portion, and
a percentage content of the acidic group-containing monomer unit present in the core portion of the particulate polymer B when the amount of all monomer units included in the particulate polymer B is taken to be 100 mass % is 0.5 mass % or more and 3.0 mass % or less.
2. The binder composition for a non-aqueous secondary battery porous membrane according to claim 1 , wherein a percentage content of the nitrile group-containing monomer unit present in the core portion of the particulate polymer B when the amount of all monomer units included in the particulate polymer B is taken to be 100 mass % is 20 mass % or more and 80 mass % or less.
3. The binder composition for a non-aqueous secondary battery porous membrane according to claim 1 , wherein the particulate polymer B has a volume-average particle diameter of not less than 300 nm and not more than 1,000 nm.
4. A slurry composition for a non-aqueous secondary battery porous membrane comprising:
the binder composition for a non-aqueous secondary battery porous membrane according to claim 1 ; and
non-conductive particles.
5. A porous membrane for a non-aqueous secondary battery formed from the slurry composition for a non-aqueous secondary battery porous membrane according to claim 4 .
6. A non-aqueous secondary battery comprising a positive electrode, a negative electrode, a separator, and an electrolyte solution, wherein
at least one battery component selected from the group consisting of the positive electrode, the negative electrode, and the separator includes the porous membrane for a non-aqueous secondary battery according to claim 5 .
7. A non-aqueous secondary battery production method for producing a non-aqueous secondary battery according to claim 6 , comprising
adhering a separator according to claim 6 and at least one of a positive electrode according to claim 6 and a negative electrode according to claim a porous membrane according to claim 6 for the non-aqueous secondary battery according to claim 6 .
8. The non-aqueous secondary battery production method according to claim 7 , wherein the adhering includes either or both of pressing and heating a laminate in which the separator and at least one of the positive electrode and the negative electrode are stacked via the porous membrane for a non-aqueous secondary battery.