Abstract: A film for a resistance layer for an electric-thermal print system, which comprises from 50 to 85% by weight of a polycarbonate resin and from 15 to 50% by weight of carbon black, and which further contains from 0.1 to 30 parts by weight, relative to 100 parts by weight of the polycarbonate resin, of an elastomer.

Abstract: Disclosed is a vibration damping composite laminate of the type comprising a viscoelastic polymer composition layer interposed between two layers of metal, which is high in the damping effectiveness and can readily be spot-welded to metal structures. Essentially the polymer composition is a blend of a polyvinyl acetal resin and particulate carbon which amounts to 10-80 wt % of the composition, on condition that the ratio of the mean particle size of the particulate carbon to the thickness of the polymer composition layer is from 0.5 to 1.7. Optionally the polymer composition may further comprise a polyolefine resin and/or a plasticizer.

Abstract: In a process for preparing polyolefin by polymerizing an olefin in the presence of a catalyst system combining an organo-aluminum compound and a titanium containing solid catalytic component prepared by mixing (a) a silanol compound (b) a Grignard reagent and (c) a titanium tetrahalide, the components (a) (b) or (c) or the reaction mixture of two or three components thereof is contacted with (d) one or more electron donor selected from the group consisting of amines, carboxylic acid amides, phosphines, phosphine oxides, phosphoric esters, phosphorous esters, phosphoric acid amides, ketones and carboxylic esters. The polyolefin having high isotactic index can be obtained.

Abstract: A propylene-ethylene block copolymer is produced in the presence of a catalytic system essentially comprising an organoaluminum compound and a solid titanium trichloride catalytic complex having an atomic ratio of Al to Ti of less than 0.15 and having a complexing agent in two stages of polymerization;(a) a first stage for polymerizing propylene in the presence of a liquid propylene and hydrogen to produce a propylene homopolymer having a melt flow index of 1 to 150 at a ratio of 70 to 95% by weight based on a total of polymers; and(b) a second stage for copolymerizing propylene and ethylene in the presence of hydrogen and a liquid propylene at a concentration of propylene in vapor phase based on a total of propylene and ethylene in vapor phase of 50 to 85 mol. % and at a concentration of hydrogen in vapor phase based on a total of propylene and ethylene in vapor phase of 0.5 to 30 mol %, to produce ethylene-propylene copolymer having a melt flow index of 10.sup.-7 to 0.

Abstract: A fine solid titanium trichloride is used as a catalyst for a polymerization of an .alpha.-olefin. The solid titanium trichloride is produced by precipitating it at lower than 150.degree. C. from a liquid titanium trichloride complex in the presence of an ester having the formula ##STR1## wherein R.sup.1 and R.sup.2 respectively represent a hydrocarbon moiety and total carbon atoms of R.sup.1 and R.sup.2 are 10 or more.