Abstract: To provide a composite porous film in which thermal shrinkage is satisfactorily suppressed even when temperature exceeds a melting temperature of a polyolefin resin, adhesion between a microporous membrane and a heat-resistant layer is improved, and dropout of an inorganic filler is suppressed. The composite porous film is composed of the heat-resistant layer formed of the inorganic filler and a binder, and the microporous membrane formed of the polyolefin resin, and the composite porous film having a primary particle size of the inorganic filler in the range of 5 nanometers to 100 nanometers.

Abstract: To provide a composite porous film in which thermal shrinkage is satisfactorily suppressed even when temperature exceeds a melting temperature of a polyolefin resin, adhesion between a microporous membrane and a heat-resistant layer is improved, and dropout of an inorganic filler is suppressed. The composite porous film is composed of the heat-resistant layer formed of the inorganic filler and a binder, and the microporous membrane formed of the polyolefin resin, and the composite porous film having a primary particle size of the inorganic filler in the range of 5 nanometers to 100 nanometers.

Abstract: The present invention provides propylene/ethylene random copolymers characterized in that: an ethylene content (Ew) is 0.1-10 wt %, a relationship between an isolated ethylene content (E1) and the ethylene content (Ew) is represented by the following equation E1>0.85−0.01 Ew 2,1- and 1,3-propylene units present in a polymer chain are 0-1 mol %, a weight average molecular weight (Mw) is in the range of 40,000-1,000,000, and a ratio (Mw/Mn) of the weight average molecular weight (Mw) to a number average molecular weight(Mn) is in the range of 1.5-3.8. The copolymers are suitable for a base resin for a molding material for the production of a wide variety of molded articles which are high in randomness and excellent in stiffness, heat resistance and transparency.

Abstract: There are provided propylene-ethylene copolymers from which there are made molded articles having excellent heat resistance and films having both low temperature heat-sealing characteristics and stiffness, processes for the production thereof and molded articles. The propylene-ethylene copolymers contain 0.01-15 mol % of an ethylene unit and are characterized by that in the chain structure determined by NMR, triad (PEP), triad (EEE) and a ratio (N.sub..alpha..beta.) of all .alpha., .beta.-methylene carbons to all propylene units are in the specified range, a weight average molecular weight is 50,000-1,500,000 and a molecular weight distribution (Mw/Mn) is 1.2-3.8. The copolymers can be produced by copolymerizing ethylene and propylene in the presence of a catalyst in which the specified chiral transition metal compound (metallocene) and aluminoxane are combined.

Abstract: A process for the production of a high stereoregular polypropylene wherein(a) an isotactic pentad (m m m m) is 0.950 to 0.995,(b) a syndiotactic pentad (r r r r) is 0 to 0.01,(c) a different bond due to 2,1- and 1,3-insertions of propylene monomer is 0 to 0.3 mol %,(d) an absence of a terminal double bond is confirmed,(e) a weight average molecular weight (Mw) is 50,000 to 1,000,000 and(f) a ratio (Mw/Mn) of the weight average molecular weight (Mw) to a number average molecular weight (Mn) is 1.5 to 3.8, (a) to (d) being determined from .sup.13 C NMR spectra, comprising polymerizing propylene in the presence of hydrogen using a catalyst comprising a chiral transition metal compound and an aluminoxane, the transition metal compound being represented by the formula of Q(C.sub.5 H.sub.4-m R.sup.1.sub.m) (C.sub.5 H.sub.4-n R.sup.2.sub.n)MXY wherein (C.sub.5 H.sub.4-m R.sup.1.sub.m) and (C.sub.5 H.sub.4-n R.sup.2.sub.n) represent a substituted cyclopentadienyl group; m and n are an integer of 1 to 3; R.sup.

Abstract: A polypropylene composition comprising 20 to 95% by weight of a stereoregular polypropylene characterized by the specified physical properties determined from .sup.13 C NMR spectra and 5 to 80% by weight of an .alpha.-olefin copolymer comprising 10 to 90% by weight of an .alpha.-olefin and 10 to 90% by weight of at least one of other .alpha.-olefins. The polypropylene composition demonstrates good balance of rigidity and impact resistance, high heat resistance and high toughness, when used as molding materials.