Abstract: A rubber composition containing an isoprene homopolymer or copolymer having a glass transition temperature of not less than -50.degree. C. and a Mooney viscosity of 20 to 120. The composition can provide a cured rubber having a high wet road gripping force and a small dynamic heat generating characteristic, and is very suitable for use in tires of automobiles.

Abstract: A catalyst component is a transition metal composition which is obtained by reacting together an inert particulate material, an organic magnesium compound, a halogen-containing compound such as carbon tetrachloride silicon tetrachloride or boron trichloride and a specified transition metal compound such as VOCl.sub.3, bis(n-butoxy) titanium dichloride or zirconium tetrabenzyl. The catalyst component obtained can be used, together with an organic metal compound, to give an olefin polymerization catalyst. The catalyst can be used to effect the polymerization of olefin monomers, for example, the copolymerization of ethylene with an alpha-olefin monomer such as butene-1 in a fluidized bed reactor.

Abstract: Poly(vinyl acetate) latex reacted with an aldehyde at acid pH to prepare crosslinked poly(vinyl alcohol) suitable as water-loss agent in drilling fluids.

Abstract: Large pore volume (.gtoreq.1.4 cc/g) silica is obtained by slowly drying an acidic (pH .ltoreq.3.5) silica hydrogel. The gel is useful in connection with chromium as an ethylene polymerization catalyst.

Abstract: The hydrocarbon fluid friction reducing properties of copolymers of two or more alpha-monoolefins having 4 to 20 carbon atoms is improved by copolymerizing the monomers in the liquid state by means of a Ziegler catalyst at a temperature of about 0.degree. C. or lower.

Abstract: There is disclosed a process for the regulation of the molecular weight of high cis polybutadiene prepared by polymerizing butadiene under solution polymerization conditions employing as the catalyst system a mixture of (a) organoaluminum compounds; (b) organonickel compounds; and (c) fluorine containing compounds; said polymerization being conducted in the presence of nonconjugated diolefins of the formula of the structure ##STR1## wherein R.sub.1 may be; --CH.sub.2 --; --C.sub.2 H.sub.4 --; --C.sub.3 H.sub.6 --; ##STR2## and R.sub.2 may be H, --CH.sub.3, --C.sub.2 H.sub.5 or --C.sub.3 H.sub.7 and R.sub.2 is trans to R.sub.1.

Abstract: Polyvinyl alcohol based sizing solution containing a small amount of quaternary (e.g., dialkyldimethyl) ammonium salt or quaternary imidazolinium salt additives provide good operability during application and weaving and results in fabric having improved finishing performance.

Abstract: Polybutadiene having high cis-1,4-configuration and dissolved in substantially anhydrous liquid organic solvent is reacted with chlorine, bromine or a mixture thereof. The solvent consists essentially of a mixture of one or more perhalogenated alkanes and one or more partially halogenated alkanes and fine particles of substantially thermoplastic halogenated polybutadiene precipitate from the solvent. The fine particles are separated from the bulk of the solvent.

Abstract: Olefins are polymerized in the presence of chromium-containing catalysts which have been improved by depositing the chromium onto the inorganic oxide support in the vapor phase rather than as an inorganic or organic compound. The resulting polymers exhibit a higher molecular weight as compared to those polymers prepared in the presence of such chromium-containing catalysts prepared in the conventional manner.

Abstract: A propylene-ethylene block copolymer in the presence of a catalyst comprises as main components, a solid titanium-containing catalytic component and an organoaluminum compound having the formulaAIR.sub.m.sup.1 Cl.sub.3-m(R.sup.1 represents a C.sub.1-20 hydrocarbon moiety; and m is 3.gtoreq.m>1.5) by producing a homopolymer of propylene or a propylene-ethylene copolymer by polymerizing propylene or both propylene and ethylene at a vapor phase propylene concentration of 90 mol % or higher based on the sum of propylene and ethylene in a first step and producing a propylene-ethylene block copolymer by copolymerizing propylene and ethylene at a vapor phase propylene concentration of less than 90 mol % based on the sum of propylene and ethylene in the presence of the polymer resulted in the first step and the catalyst in a second step is produced by newly adding an aluminum compound having the formulaAlR.sub.n.sup.2 X.sub.3-n(R.sup.2 represents a C.sub.

Abstract: Process for polymerizing by ring opening polymerization of a norbornene-type monomer, or a mixture thereof, with or without at least one other polymerizable monomer, in presence of an alkylaluminum halide cocatalyst and an organoammonium molybdate or tungstate catalyst that is soluble in a hydrocarbon reaction solvent and the norbornene-type monomer.

Abstract: Vinyl halide polymer is prepared by bulk liquid phase polymerization of vinyl halide monomer in the presence of a minor proportion, based on the weight of the polymerization reaction mass, of isobutane diluent followed by application of reduced pressure to remove diluent and unreacted monomer from the polymer.The product exhibits improved porosity and molten color stability compared to vinyl halide polymers prepared in bulk in the presence of conventional alkane hydrocarbon diluents.

Abstract: A process for producing an antithrombogenic vinyl acetate polymer or a hydrolyzate thereof which comprises treating the vinyl acetate polymer or hydrolyzate with a solution of a fibrinolytic enzyme so as to fix the fibrinolytic enzyme to the polymer. The resulting antithrombogenic vinyl acetate polymer or hydrolyzate is advantageously used in a material which comes into contact with the blood in use and is especially useful in a surgical tube.

Abstract: Ethylene-butadiene-isoprene terpolymers consisting of more than 80 mol % of alternating ethylene-diene units and in which more than 95 mol % of the diene units built into the polymer are in the 1,4-configuration.

Abstract: In producing a block copolymer resin having vinyl aromatic hydrocarbon polymer blocks such as of styrene and polymer blocks primarily composed of conjugated diene such as of butadiene successively through living polymers using an organolithium compound as a catalyst in an aliphatic solvent, the vinyl aromatic hydrocarbon monomer for forming the vinyl aromatic hydrocarbon polymer block is added at a controlled rate, at the stage when the vinyl aromatic hydrocarbon content in the polymer formed has reached a certain value, higher than the polymerization rate of the vinyl aromatic hydrocarbon monomer at the polymerization temperature but at a rate which can maintain the solubility parameter of the liquid phase portion in the polymerization system at 7.7 or less, whereby a block copolymer resin with good transparency and impact strength can be produced with good productivity.

Abstract: In a process for producing a rubbery olefinic copolymer which comprises random-copolymerizing at least two olefins in the presence of a catalyst composed of (A) a titanium compound and (B) an organometallic compound of a metal of Groups I to III of the periodic table, the improvement wherein the titanium compound (A) of the catalyst is a solution of a solid titanium halide in a hydrocarbon solvent, a halogenated hydrocarbon solvent or a mixture of both, said solid titanium halide being rendered soluble in said solvent.

Abstract: Conjugated diene homo- or copolymers having chemically bound antioxidant functional groups are prepared by the reaction of polymer-alkali metal with certain antioxidants containing a functional group reactable polymer-alkali metal, providing both coupling and bound anti-oxidant groups. These polymers having antioxidant functional groups chemically attached into the polymer chain have better aging stability than similar polymers containing non-bound antioxidants.

Abstract: A method for initiating polymerization of ethylene in a fluidized bed reactor employing a supported chromium oxide as catalyst in a smooth and controlled manner, and for reducing the start-up time required to initiate such polymerization, by adding a dialkylzinc compound to the reactor prior to the commencement of polymerization and subjecting the reactor containing such dialkylzinc compound to conditions conventionally employed in the polymerization of ethylene with such catalyst.

Abstract: A substantially continuous, gas-impermeable, film is disclosed including a combination of metal orthophosphate and dialdehyde-treated poly(vinyl alcohol). Barrier properties of a laminate utilizing the film are greatly improved by a heat treatment.

Abstract: Hard, infusible, discrete beads of crosslinked copolymer are prepared by free-radical catalyzed polymerization of a monomer mixture in aqueous dispersion wherein a minor amount of a modifier, specifically an organic compound containing acetylenic or allylic unsaturation having the ability to moderate the rate of polymerization, is incorporated in the monomer mixture. Ion exchange resins having improved mechanical strength are obtained by attaching functional groups to the copolymer.