Abstract: Process and device for cooling a mixture of polymer and monomer from a reactor in which ethylene is polymerized or copolymerized at a pressure greater than 1,000 bars between a pressure-reduction valve located downstream of the reactor and a medium pressure separator. The cooling is achieved by injecting monomer at a pressure below that of the separator using a device with a nozzle cross-section S.sub.1 through which the mixture from the reactor passes, a convergent mixing zone in which the mixture is mixed with the monomer injected, which is supplied at a flow rate q, and a diffuser of throat cross-section S.sub.3, which makes it possible to bring the mixture to the pressure of the separator. The dimensions of the device are such that the ratio Q/S.sub.1 is between 0.20 and 1.35 t/hr.mm2 and the ratio (q+Q/S.sub.3 is between 0.1 and 0.3 t/hr.mm2.

Abstract: A method for preparing a composition of matter comprising silica and titanium, convertible to a catalyst suitable for olefin polymerization by the addition of chromium and the process performable therewith, the preparation involving adding an alkali metal silicate to an acid containing a titanium compound, and recovering a dry gel for use as a polymerization catalyst upon the addition of chromium.

Abstract: Olefin polymerization catalysts are prepared by depositing an organophosphoryl chromium product and an aluminum compound on an inorganic support material, and heating the support material in a non-reducing atmosphere at a temperature above about 300.degree. C. up to the decomposition temperature of the support material.

Abstract: An olefin or mixture of olefins is polymerized in a hydrocarbon diluent in a turbulent reaction zone to produce particles of polymer which are substantially insoluble in the diluent (particle form process). Fouling of the reactor by adherence of polymer particles to the walls of the reactor is reduced by adding to the reaction medium a composition which comprises a mixture of (a) a polysulfone copolymer, (b) a polymeric polyamine, and (c) an oil-soluble sulfonic acid.

Abstract: A novel and improved method for polymerizing a vinyl monomer in a polymerization reactor is provided. The inner walls of the polymerization reactor and other surfaces coming into contact with the monomer are coated with an aqueous liquid containing at least one alkali metal or ammonium salt of an anionic dye of the sulfonic carboxylic acid form and having a pH value adjusted not to exceed 7 by aid of a pH adjusting agent, and the thus coated surfaces are dried with heat before the polymerization is conducted. The method serves to greatly reduce the deposition of polymer scale on those surfaces and, consequently, improve the productivity as well as the quality of polymer product.

Abstract: An improved method for preparing ethylene polymers with certain supported chromium [II] catalysts wherein the improvement comprises employing said catalyst in the presence of phenolic antioxidant.

Abstract: A process for the continuous high pressure polymerization of ethylene in a polymerization system which comprises a polymerization zone (A), a high pressure product isolation zone (B), a throttling and control system (C), a low pressure product isolation zone (D), a second throttling and control system (E) and a discharge extruder (F), and wherein, according to the invention, the level of the ethylene polymer in the high pressure product isolation zone (B) and in the low pressure product isolation zone (D) is varied periodically. The process gives an ethylene polymer of improved homogeneity, which when used to manufacture films does not tend to form specks or fisheyes.

Abstract: A process for the manufacture of olefin polymers by polymerizing .alpha.-monoolefins at relatively low temperatures and relatively low olefin pressures by means of a catalyst obtained from a silicate carrier (component a), an aluminum compound (component b) and a chromium compound (component c). The catalyst is obtained by (1) in a first stage, initially (1.1) charging a particular silicate carrier (component a) with (1.2) a mixture of (1.2.1) an aluminum salt or a mixture of an aluminum salt with up to 80 mole%, based on the salt mixture, of a nickel-II salt (component b) and (1.2.2) a chromium compound (component c), this compound being chromium trioxide or a compound which is converted to chromium trioxide under the conditions of stage (2), by treatment with a solution of the mixture (1.2), and (2), in a second stage then maintaining the product, obtained from stage (1), for a certain time at a high temperature in an anhydrous oxygen-containing gas stream.

Abstract: Inorganic hydrogels, e.g., silica-containing hydrogels, are contacted with contacting agents comprising oxygen-containing organic compounds and then dried to remove the liquid components therefrom. The contacting agent can also be an oxygen-containing organic compound in combination with a liquid hydrocarbon or an oxygen-containing compound in combination with a liquid hydrocarbon and a surfactant. The hydrogel can be treated with a catalytic metal compound prior to or during the contacting with the contacting agents in order to produce a composition after drying and calcining that is catalytically active for olefin polymerization. The treated hydrogel can also, after drying, be treated anhydrously with a catalytic metal compound to produce a composition that is active for 1-olefin polymerization upon calcination.

Abstract: A continuous process for producing polyethylene or copolymers of ethylene with other copolymerizable compounds at a pressure of at least 1,000 kg/cm.sup.2 in a tubular reactor under steady conditions without imposing on the polymerization system flow pulses, while keeping the monomer conversion at 35% or lower and the melt index of the polymer at 0.1 or more.

Abstract: A process and apparatus for the polymerization of ethylene in at least one multizone reactor at a pressure of 300 to 2500 bars and at a temperature of 150 to 350.degree. C. The reaction mixture is passed from the reactor to a separator at a pressure of 50 to 500 bars in which the polymer separates from the gas. The polymer is then passed to a hopper at a pressure of 1 to 20 bars in which the major part of the gas remaining dissolved in the polymer is removed. The gas from the separator is recompressed and is returned only to the first zone of the reactor.

Abstract: Hydrocarbon-soluble compositions useful as the transition metal component in the Ziegler polymerization of .alpha.-olefins are provided by reacting molecular nitrogen or hydrogen with a transition metal compound such as titanium trichloride to form a dinitrogen or dihydrogen complex of the transition metal compound.

Abstract: Gas-phase polymerization of an .alpha.-olefin, especially propylene, in a stirred or fluidized bed of substantially uniform and approximately spherical carrier particles of an .alpha.-olefin polymer of diameter 100-500 .mu.m, using a catalyst comprising an organo-metallic compound and a solid transition metal compound which has a particle size of less than 5 .mu.m, produces a propylene polymer having unexpectedly good powder flow characteristics. The transition metal compound is conveniently a titanium trichloride-containing material which has been treated with a dialkyl ether solution.

Abstract: Graft copolymers of resin-forming monomers on monoolefin-type rubber spines, particularly ethylene-propylene-non-conjugated diene rubber spines, are made in solution with the aid of a free radical polymerization initiator. The graft copolymers have high impact strength.

Abstract: A polypropylene having a strongly reduced melting temperature and improved optical properties is obtained by copolymerization of propylene with small quantities of ethylene and butene-(1).

Abstract: Bingham fluid compositions are provided which contain a functional material such as a polymerization initiator dispersed in a solid continuous phase, which is a mixture of a wax and a liquid hydrocarbon. Such compositions are prepared by heating the wax and the liquid hydrocarbon to form a melt and dispersing the functional material in the melt. Upon cooling, the composition solidifies with the functional material being uniformly dispersed throughout the continuous solid phase. The compositions, while solid at ambient temperature and pressure, assume the flow characteristics of a liquid under an applied pressure and can be pumped to feed the functional material to a polymerization reactor or molten polymer on a continuous basis.

Abstract: Ethylene-vinyl acetate copolymers are carboxylated by copolymerizing an alpha, beta-unsaturated carboxylic acid and/or anhydride thereof with at least one vinylidene monomer having the formula: ##STR1## wherein X and Y can be the same or different, and each represents hydrogen, chlorine, alkyl, acetoxy, carboxylic acid ester group or cyano; with an ethylene-vinyl acetate copolymer in the presence of a polymerization initiator in a reaction medium of a ketone compound or a mixture of a ketone compound and an acetic acid ester, wherein the reaction is conducted in a heterogeneous state.

Abstract: An improved polyvinyl halide or a polyvinyl halide copolymer containing up to 50 percent of a comonomer can be obtained by post polymerizing in a single stage or two-stage bulk process in contact with a base polymer, the same or different monomer as the monomer used to form the base polymer. Compositions produced by the process of the invention are useful in making films, coated fabrics and molded objects. The liquid phase post polymerization process of the invention is applicable to base polymers in powder form prepared by emulsion, suspension and bulk polymerization processes. The base polymer can be present in a polymerization mixture in which only a partial amount of monomer has been converted to base polymer such as in a two-stage polymerization process or the base polymer can be used in dry, solid form. Polymers of the invention have improved bulk density and reduced plasticizer uptake and can be used to prepare fabric coatings.

Abstract: An improved process for grafting vinyl chloride onto ethylene-vinyl acetate or ethylene-alkyl acrylate copolymers in the gel phase in the presence of radical formers soluble in the monomer wherein the ethylene-vinyl acetate or ethylene-alkyl acrylate copolymer is in powder form and a combination of at least two initiators having different decomposition temperatures are employed during the grafting, the resultant grafted copolymer and the use of the same as an impact strength improving component or polyvinyl chloride or vinyl chloride copolymers.

Abstract: A melt finish process is disclosed herein for working up solid, particulate polymer from a vapor state polymerization reactor, which reactor employs high yield catalysts, whereby the polymer is moved out of the reactor and into a post polymerization zone characterized by essentially adiabatic polymerization and the heat of such polymerization is used in raising the temperature of and melting said solid, particulate polymer to form molten polymer for further processing.