Porous body, separator for lead acid storage batteries, and lead acid storage battery

A lead acid storage battery comprising a porous body as a separator for lead acid storage batteries, the porous body containing sheath-core type binder fibers and a resin binder,

• wherein a resin binder solid content is contained in an amount of more than 5.0 parts by weight and less than 50 parts by weight relative to 100 parts by weight of the porous body, and when P (N) is a penetration strength of the porous body and B (g/m2) is a basis weight of the porous body, P and B satisfy P/B>0.070,
• wherein the resin binder is at least one selected from the group consisting of an acrylic-based binder and a styrene-based resin binder,
• wherein the porous body contains inorganic fibers and inorganic particles,
• wherein the porous body contains a network structure formed by the inorganic fibers,
• wherein the inorganic fibers and inorganic particles are bound by a melting component of the resin binder or sheath-core type binder fibers,
• wherein a core material of the sheath-core type binder fibers is at least one selected from polyethylene terephthalate (PET), poly-1,3-trimethylene terephthalate (PTT), and polybutylene terephthalate (PBT),
• wherein a sheath material of the sheath-core type binder fibers is polyester,
• wherein the porous body contains glass fibers, and when a weight of the inorganic particles contained in the porous body is Wi (g), a weight of the glass fibers is Wg (g), and a weight of the resin binder solid content is Wb (g), Wi, Wg, and Wb satisfy 1.0≤(Wi+Wg)/Wb≤4.5,
• wherein a content of the sheath-core type binder fibers with respect to 100 parts by weight of the porous body is 35 parts by weight to 45 parts by weight, and
• wherein a melting component of the sheath-core type binder fibers is contained in an amount of 17 parts by weight or more and 25 parts by weight or less, relative to 100 parts by weight of the separator.