Vinylidene fluoride-based core / shell polymer and utilized in the non-aqueous electrochemical device

A rubbery core part vinylidene fluoride content consists 30 to 90 wt% of the crosslinked vinylidene fluoride copolymer (a), at greater than vinylidene fluoride content of the crosslinking vinylidene fluoride copolymer (a) core having a ratio of shell portion and the weight ratio consisting of vinylidene fluoride polymer (b) (a) / (b) is 30 / 70-90 / 10 and having a 80% or more by weight of vinylidene fluoride content / shell type polymer (A). The vinylidene fluoride-based core / shell type polymer (A) is excellent in mechanical properties and 耐非 water electrolysis solution properties, including flexibility, softness excellent in combination with the active material powder and electrode collector suitable for use as a non-aqueous electrochemical device binder to form the electrode mixture layer exhibiting adhesion with.