Abstract: Disclosed in an olefin polymerization catalyst comprising a transition metal compound having at least two transition metals in which at least one of said metals is bonded to a ligand having a cyclopentadienyl skeleton, at least one of said metals is selected from Sc, Y, Ti, Zr, Hf, V, Nb, Ta, Cr, Mo, W and lanthanoid metals and at least on of the others is selected from the specific transition metals; and an organoaluminum oxy-compound or an organoboron compound. Corresponding to the kind of the metal combined with said metal selected from Sc, Y, Ti, Zr, Hf, V, Nb, Ta, Cr, Mo, W and lanthanoid metals, the olefin polymerization catalyst exhibit a property to give polymers having a wide molecular weight distribution in spite of the catalyst system using one kind of a transition metal compound, or to give polymers having high molecular weight and be excellent in the polymerization activity at low polymerization temperature.

Abstract: The semiaromatic polyamide of the invention comprises 40 to 90% by mol of (A) recurring units derived from terephthalic acid and an aliphatic diamine of 4 to 12 carbon atoms, 0 to 50% by mol of (B) recurring units derived from isophthalic acid and an aliphatic diamine of 4 to 12 carbon atoms, 0 to 60% by mol of (C) recurring units derived from an aliphatic dicarboxylic acid of 4 to 18 carbon atoms and an aliphatic diamine of 4 to 12 carbon atoms and 0 to 50% by mol of (D) recurring units derived from a lactam or an aminocarboxylic acid of 6 to 20 carbon atoms, and has a content of boiling water-soluble components (MO components) of not more than 0.25% by weight. The semiaromatic polyamide has a low content of the MO components, so that mold contamination hardly brought about in the molding process, and also molded articles of good heat resistance can be produced.

Abstract: Disclosed in an olefin polymerization catalyst comprising a transition metal compound having at least two transition metals in which at least one of said metals is bonded to a ligand having a cyclopentadienyl skeleton, at least one of said metals is selected from Sc, Y, Ti, Zr, Hf, V, Nb, Ta, Cr, Mo, W and lanthanoid metals and at least on of the others is selected from the specific transition metals; and an organoaluminum oxy-compound or an organoboron compound. Corresponding to the kind of the metal combined with said metal selected from Sc, Y, Ti, Zr, Hf, V, Nb, Ta, Cr, Mo, W and lanthanoid metals, the olefin polymerization catalyst exhibit a property to give polymers having a wide molecular weight distribution in spite of the catalyst system using one kind of a transition metal compound, or to give polymers having high molecular weight and be excellent in the polymerization activity at low polymerization temperature.