Abstract: Disclosed is a porous membrane used for a secondary battery, such as lithium-ion secondary battery, wherein strength is improved and break is difficult to occur while maintaining lithium-ion conductivity. The porous membrane for a secondary battery comprising a binder for the porous membrane and a nonconductive particle, wherein the binder for the porous membrane is a polymer particle having a hetero phase structure, in which internal layer is a polymer wherein vinyl monomer components are polymerized and outer layer is a polymer wherein monomer components containing a hydrophilic functional group are polymerized. The hydrophilic functional group is at least one selected from the group consisting sulfonic acid group, carboxyl group, hydroxyl group and epoxy group.

Abstract: Disclosed is a porous membrane used for a secondary battery, such as lithium-ion secondary battery, wherein strength is improved and break is difficult to occur while maintaining lithium-ion conductivity. The porous membrane for a secondary battery comprising a binder for the porous membrane and a nonconductive particle, wherein the binder for the porous membrane is a polymer particle having a hetero phase structure, in which internal layer is a polymer wherein vinyl monomer components are polymerized and outer layer is a polymer wherein monomer components containing a hydrophilic functional group are polymerized. The hydrophilic functional group is at least one selected from the group consisting sulfonic acid group, carboxyl group, hydroxyl group and epoxy group.

Abstract: An acrylic rubber, comprising an alkoxyalkyl(meth)acrylate monomer unit in an amount of 70.1 to 99.8 wt %, a methacrylonitrile monomer unit in an amount of 0.1 to 9.9 wt % and a butenedionic acid monoester monomer unit in an amount of 0.1 to 20 wt %; and a cross-linkable acrylic rubber composition made by containing the acrylic rubber and a cross-linking agent. According to the invention, it is possible to provide a cross-linkable acrylic rubber composition having excellent scorch stability and an acrylic rubber cross-linked product, which can be obtained by cross-linking the cross-linkable acrylic rubber composition, having excellent heat resistance, cold resistance and fuel oil resistance.