A method of preparing an aromatic vinyl compound-vinyl cyanide compound polymer includes polymerizing a reaction mixture containing an aromatic vinyl compound, a vinyl cyanide compound, and an organic solvent in a reactor and transferring the vaporized reaction mixture present in the upper space of the reactor to a heat exchanger via a pipe and condensing the vaporized reaction mixture. The condensed reaction mixture is transferred to one side of the pipe and sprayed into the pipe, the flow velocity of the reaction mixture vaporized in the reactor is reduced, and temperature is lowered. Accordingly, a phenomenon wherein polymer particles in a reactor are sucked into a heat exchanger is prevented, and occurrence of polymerization in the heat exchanger is suppressed. Therefore, productivity and quality may be improved.

A method of preparing an aromatic vinyl compound-vinyl cyanide compound polymer includes polymerizing a reaction mixture containing an aromatic vinyl compound, a vinyl cyanide compound, and an organic solvent in a reactor and transferring the vaporized reaction mixture present in the upper space of the reactor to a heat exchanger via a pipe and condensing the vaporized reaction mixture. The condensed reaction mixture is transferred to one side of the pipe and sprayed into the pipe, the flow velocity of the reaction mixture vaporized in the reactor is reduced, and temperature is lowered. Accordingly, a phenomenon wherein polymer particles in a reactor are sucked into a heat exchanger is prevented, and occurrence of polymerization in the heat exchanger is suppressed. Therefore, productivity and quality may be improved.

Method for producing a thermoplastic moulding compound containing: up to 40 wt. % of a graft copolymer A, containing 50-70 wt. % graft base A1 from an acrylic ester polymer and 30-50 wt. % of a graft shell A2, and 0-90 wt. % of a hard matrix B, wherein the reaction for producing the graft copolymer A is carried out in the presence of 0.01 to 4 times the molar amount of sodium carbonate, relative to the molar amount of initiator, wherein the reaction for producing copolymer A is carried out in the presence of 0.1 to 1 wt. % of an emulsifier relative to the amount of the respective monomers used, and wherein during the polymerisation reaction, during the post-polymerisation and/or after the polymerisation reaction, water or an aqueous alkali solution are added to the reaction mixture for producing the graft copolymer A.

Method for producing a thermoplastic moulding compound containing: up to 40 wt. % of a graft copolymer A, containing 50-70 wt. % graft base A1 from an acrylic ester polymer and 30-50 wt. % of a graft shell A2, and 0-90 wt. % of a hard matrix B, wherein the reaction for producing the graft copolymer A is carried out in the presence of 0.01 to 4 times the molar amount of sodium carbonate, relative to the molar amount of initiator, wherein the reaction for producing copolymer A is carried out in the presence of 0.1 to 1 wt. % of an emulsifier relative to the amount of the respective monomers used, and wherein during the polymerisation reaction, during the post-polymerisation and/or after the polymerisation reaction, water or an aqueous alkali solution are added to the reaction mixture for producing the graft copolymer A.

A process for producing polyethylene polymers including contacting ethylene and at least one C.sub.3 to C.sub.8 alpha-olefin comonomer with a polymerization catalyst on a particulate support in a fluidized bed polymerization reactor under conditions effective to polymerize at least part of the ethylene and comonomer and produce the polyethylene polymers, wherein the support has a d.sub.10 particle size as measured by laser diffraction of at least 18 microns, is provided.

An olefin polymerisation method and arrangement comprising polymerising at least one olefin in gas phase in a fluidised bed in the presence of an olefin polymerisation catalyst in a polymerisation reactor having a vertical body; a generally conical downwards tapering bottom zone; a generally cylindrical middle zone, above and connected to said bottom zone; and a generally conical upwards tapering top zone above and connected to said middle zone wherein (i) fluidisation gas is introduced to the bottom zone of the reactor from where it passes upwards through the reactor; (ii) the fluidisation gas is withdrawn from the top zone of the reactor; (iii) a fluidised bed is formed within the reactor where the growing polymer particles are suspended in the upwards rising gas stream; and wherein the polymerisation reactor has an operating temperature set point and which reactor comprises at least one temperature measurement sensor, wherein a temperature difference (DT) between the temperature measurement sensor (Tm), and the operating temperature set point (Ts) of the reactor is equal to or less than 10 C.

An olefin polymerisation method and arrangement comprising polymerising at least one olefin in gas phase in a fluidised bed in the presence of an olefin polymerisation catalyst in a polymerisation reactor having a vertical body; a generally conical downwards tapering bottom zone; a generally cylindrical middle zone, above and connected to said bottom zone; and a generally conical upwards tapering top zone above and connected to said middle zone wherein (i) fluidisation gas is introduced to the bottom zone of the reactor from where it passes upwards through the reactor; (ii) the fluidisation gas is withdrawn from the top zone of the reactor; (iii) a fluidised bed is formed within the reactor where the growing polymer particles are suspended in the upwards rising gas stream; and wherein the polymerisation reactor has an operating temperature set point and which reactor comprises at least one temperature measurement sensor, wherein a temperature difference (DT) between the temperature measurement sensor (Tm), and the operating temperature set point (Ts) of the reactor is equal to or less than 10 C.

A process to prepare an ethylene-based polymer, said process comprising polymerizing a mixture comprising ethylene, at a pressure greater than, or equal to, 100 MPa, in the presence of at least one free-radical initiator; and in a reactor system comprising at least one reactor and at least one Hyper-compressor, and wherein at least one oil formulation, optionally comprising one or more lubrication agents, is added to the Hyper-compressor; and wherein at least one of the following steps takes place: A) thermally treating the one or more lubrication agents, in an oxygen-free atmosphere, to achieve a peroxide level10 ppm, based on the weight of the lubrication agent(s), and then adding said agent(s) to the oil formulation, prior to adding the oil formulation to the Hyper-compressor; or B) thermally treating the oil formulation, in an oxygen-free atmosphere, to achieve a peroxide level10 ppm, based on the weight of the oil formulation, prior to adding the oil formulation to the Hyper-compressor; C) a combination of A and B.

A process to prepare an ethylene-based polymer, said process comprising polymerizing a mixture comprising ethylene, at a pressure greater than, or equal to, 100 MPa, in the presence of at least one free-radical initiator; and in a reactor system comprising at least one reactor and at least one Hyper-compressor, and wherein at least one oil formulation, optionally comprising one or more lubrication agents, is added to the Hyper-compressor; and wherein at least one of the following steps takes place: A) thermally treating the one or more lubrication agents, in an oxygen-free atmosphere, to achieve a peroxide level10 ppm, based on the weight of the lubrication agent(s), and then adding said agent(s) to the oil formulation, prior to adding the oil formulation to the Hyper-compressor; or B) thermally treating the oil formulation, in an oxygen-free atmosphere, to achieve a peroxide level10 ppm, based on the weight of the oil formulation, prior to adding the oil formulation to the Hyper-compressor; C) a combination of A and B.

The present invention relates to a process for the continuous production of a polyolefin, preferably polypropylene, in a horizontal stirred bed polymerization reactor by contacting one or more olefins, preferably propylene, with a catalyst system while stirring, said catalyst system comprising: * a procatalyst comprising i) titanium; ii) a magnesium-containing support, preferably a magnesium chloride-containing support, and iii) an internal electron donor; * optionally an external electron donor; and * a co-catalyst, being a alkyl aluminum catalyst having formula AlX.sub.nR.sub.3-n, wherein each X is independently a halide or a hydride and wherein n is 0, 1 or 2, preferably 0, and wherein R is an C1-C12 alkyl group, preferably ethyl, wherein the molar ratio of aluminum (Al) from the co-catalyst to titanium (Ti) from the procatalyst (Al/Ti) is at least 75. The present invention also relates to polyolefin prepared using said process and a shaped article comprising said polyolefin. The present invention moreover relates to the use of a titanium to aluminum ratio during the Ziegler-Natta polymerization of olefins in a horizontal stirred bed reactor to reduce the energy (power) consumption in view of a situation wherein the titanium to aluminum ratio is lower.