Patent ID: 7833654

Claim:
An adhesive-carrying porous film for use as a battery separator, which comprises: a substrate porous film such that when a probe of a probe penetrating thermomechanical analyzer, said probe having a diameter of 1 mm, is placed on the porous film under a load of 70 g to measure a thickness thereof while heating the porous film from room temperature at a rate of 2° C./minute, a temperature at which the thickness of the porous film decreases to a half of the thickness of the porous film when the probe was initially placed thereon is 200° C. or more; and a partially crosslinked adhesive carried on the substrate porous film, and having a gel fraction in a range of 5 to 80%, the partially crosslinked adhesive being prepared by carrying on the substrate porous film a reactive polymer having a functional group capable of reacting with a polyfunctional isocyanate and a polyfunctional isocyanate in such a quantity sufficient for the reactive polymer to be partially crosslinked, and then by reacting the reactive polymer with the polyfunctional isocyanate.