Patent ID: 10340492

Abstract:
To provide an ultrahigh molecular weight polyethylene stretched microporous film having high strength and heat resistance.An ultrahigh molecular weight polyethylene stretched microporous film, which comprises at least an ultrahigh molecular weight polyethylene having an intrinsic viscosity ([η]) of at least 7 dl/g and at most 60 dl/g, and which has a porosity of at least 10% and at most 70% and a breaking stress of at least 1 MPa when melt-stretched at 150° C., which uses, as the ultrahigh molecular weight polyethylene, preferably ultrahigh molecular weight polyethylene particles which satisfy (1) an intrinsic viscosity ([η]) of at least 7 dl/g and at most 60 dl/g, (2) a bulk density of at least 130 kg/m3 and at most 700 kg/m3, and (3) ΔTm (ΔTm=Tm1−Tm2) of at least 9° C. and at most 30° C., which is a difference between the melting point (Tm1) at the 1st scanning and the melting point (Tm2) at the 2nd scanning measured by DSC.