Abstract: A flexible heating sheet is composed of two heat fusible aromatic polyimide films and an electric heating element having an electric source-connecting terminal at each end which intervenes between the heat fusible aromatic polyimide films, in which each heat fusible aromatic polyimide film is covered with a heat resistant aromatic polyimide film.

Abstract: A flexible heating sheet is composed of two heat fusible aromatic polyimide films and an electric heating element having an electric source-connecting terminal at each end which intervenes between the heat fusible aromatic polyimide films, in which each heat fusible aromatic polyimide film is covered with a heat resistant aromatic polyimide film.

Abstract: Poly-.alpha.-olefin, for example, polypropylene, is produced by subjecting a feed containing an .alpha.-olefin having 3 or more carbon atoms, to a preliminary polymerization at 40.degree. C. or less in the presence of a catalyst which comprises (A) a solid catalytic ingredient prepared (a) by reacting a Grignard compound of the formula, R.sup.3 MgX wherein R.sup.3 =C.sub.1-8 alkyl and X=halogen, with a reaction product of an aluminium halide with an organic silicon compound of the formula, R.sub.n.sup.1 Si(OR.sup.2).sub.4-n, wherein R.sup.1 =C.sub.1-8 alkyl or phenyl, R.sup.2 =C.sub.1-8 alkyl, n=0, or 1 to 3, (b) bringing the resultant solid carrier into a first contact with titanium tetrahalide, (c) treating the resultant titanium-containing solid product with an organic acid ester, and, finally, (d) bringing the treated solid product into a second contact with titanium tetrahalide; (B) another catalytic ingredient consisting of a trialkyl aluminium of the formula, AlR.sub.3.sup.4 wherein R.sup.4 =C.sub.

Abstract: An ethylene polymer is produced with an excellent yield by bringing a feed containing ethylene into contact with a catalyst which comprises (A) a solid catalytic ingredient prepared (a) by reacting a Grignard compound with a reaction product of an aluminum halide with an organic silicon compound of the formula, R.sup.1.sub.n Si(OR.sup.2).sub.4-n, wherein R.sup.1 =C.sub.1-8 alkyl or phenyl, R.sup.2 =C.sub.1-8 alkyl and n=1, 2 or 3 and (b) by bringing the resultant solid reaction product into contact with titanium tetrahalide and (B) another catalytic ingredient consisting of at least one trialkyl aluminum.

Abstract: Poly.alpha.-olefin, for example, polypropylene, is produced with an excellent yield by bringing, in the presence of an organic acid ester, a feed, containing at least one .alpha.-olefin having 3 or more carbon atoms, for example, propylene, into contact with a catalyst which comprises (A) a solid catalytic ingredient prepared (a) by reacting a Grignard compound of the formula, R.sup.3 MgX wherein R.sup.3 =C.sub.1-8 alkyl and X=halogen, with a reaction product of an aluminium halide with an organic silicon compound of the formula, R.sub.n.sup.1 Si(OR.sup.2).sub.4-n, wherein R.sup.1 =C.sub.1-8 alkyl or phenyl, R.sup.2 =C.sub.

Abstract: An ethylene polymer is produced with an excellent yield by bringing a feed containing ethylene into contact with a catalyst which comprises (A) a solid catalytic ingredient prepared (a) by reacting a Grignard compound with an aluminium halide-tetraalkoxysilane reaction product and (b) bringing the resultant reaction product into contact with titanium tetrahalide and; (B) another catalytic ingredient consisting of a trialkyl aluminium.

Abstract: Poly-.alpha.-olefin having an excellent H. I. is produced with an excellent yield by bringing, in the presence of an organic acid ester, a feed, containing at least one .alpha.-olefin having 3 or more carbon atoms, into contact with a catalyst which comprises (A) a solid catalytic ingredient prepared (a) by reacting a Grignard compound with an aluminium halide-tetraalkoxysilane reaction product, (b) bringing the resultant reaction product into a first contact with titanium tetrahalide, (c) treating the resultant titanium-containing solid product with an organic acid ester, and, finally, (d) bringing the treated solid product into a second contact with titanium tetrahalide, and; (B) another catalytic ingredient consisting of a trialkyl aluminium.