摘要:
In polymerizing an olefin, for example, in a polymerization reactor with a reflux condenser, a gas mixture withdrawn from the polymerization reactor is first washed before it reaches the heat transfer surface of the reflux condenser to remove active catalyst particles and polymer particles entrained therein and then condensed to obtain a condensed liquid, and the condensed liquid is returned to the polymerization reactor whereby the heat generated in the polymerization reactor is efficiently removed without causing any clogging of pipes, etc.
摘要:
A method for producing high-molecular weight microspheres of the present invention includes the steps of dissolving or dispersing a high-molecular material in a high pressure fluid containing a supercritical fluid and an entrainer, and spraying the resultant high pressure fluid into a poor solvent to cause rapid expansion. According to the production method, high-molecular weight microspheres or coated microspheres whose average particle size can be controlled can be produced.
摘要:
In a process for producing polypropylene comprising polymerizing propylene in the presence of hydrogen and a catalyst system comprising (A) titanium trichloride obtained by reducing titanium tetrachloride with an organoaluminum compound and reacting the reduced solid with an ether represented by the formula:R.sup.1 --O--R.sup.2wherein R.sup.1 and R.sup.2 are defined hereinbefore, and a halogen compound selected from the group consisting of (i) halogen or interhalogen compounds of the formula, X.sup.1 X.sup.2.sub.a (wherein X.sup.1, X.sup.2 and a are defined hereinbefore), (ii) titanium halides, and (iii) organic halogen compounds, simultaneously or successively and (B) an organoaluminum compound, the improvement which comprises supplying ethylene together with propylene to the polymerization system such that the ethylene concentration in the vapor phase of the system based on the total amount of propylene, ethylene and hydrogen in the vapor phase of the system is 0.15 to 1.5 mol % to obtain a propylene-ethylene copolymer having an ethylene content of from 0.1 to 1.0 wt % is disclosed. The propylene-ethylene copolymer is improved in stretchability.
摘要:
A slurry containing polymer particles having an average particle diameter of 0.1 to 1 mm suspended therein is discharged smoothly from a discharge valve without valve clogging by operating the valve such that the degree of valve opening is set within a range II for a valve operating time t.sub.1 and within a range III for a valve operating time t.sub.2 ; the time t.sub.1 being from 5 to 60 seconds, the time t.sub.2 being from 1 to 10 seconds, the range II being a range of valve openings at which the valve is gradually clogged with the polymer particles discharged, and the range III being a range of valve openings at which the valve permits continuous discharge without clogging.
摘要:
A process for purifying propylene homopolymers or copolymers which comprises:(i) polymerizing or copolymerizing propylene with other unsaturated hydrocarbon monomers in liquid propylene in the presence of a catalyst system consisting essentially of (a) an activated titanium trichloride obtained by reducing titanium tetrachloride with an organo-aluminum compound followed by activation and (b) an organo-aluminum compound;(ii) introducing the resulting polymer slurry into an upper portion of a counter-current washing tower to counter-currently contact the polymer slurry with a C.sub.3 -C.sub.8 alcohol and liquid propylene, whereby said catalyst is deactivated and at the same time the propylene homopolymers or copolymers dissolved in the polymer slurry and the catalyst are removed by washing, wherein said alcohol is used in an amount 0.1 to 50 times by mole based on said organo-aluminum compound (b) and is supplied to the washing tower lower than the point of introduction of said polymer slurry, and said liquid propylene is supplied to a lower portion of the washing tower; and(iii) then after removing volatile monomers by flashing, contacting the powdery propylene homopolymers or copolymers with a gaseous epoxide at a temperature lower than melting point of said polymer or copolymer.
摘要:
A method for preparing composite microspheres of a high-molecular material and a core substance includes the steps of: dissolving a high-molecular material and dispersing a core substance in a high pressure fluid containing a supercritical fluid and an entrainer, under a shear stress of 1 Pa or more; and spraying the resultant high pressure fluid containing the high-molecular material and the core substance into a poor solvent to cause rapid expansion. According to the method composite microspheres having a uniform size of several micrometers or less, and more preferably nanometer order (a size of 1 μm or less) can be obtained.
摘要:
A particulate polyolefin molding material is disclosed. The material is comprised of a particulate polyolefin particle having a bulk density of 0.45 g/cc or more and a mean particle size of 150 to 2,000.mu., and a layer comprising a compounding additive and a binder formed on the surface of the particle. The material can be used in producing molded articles without first forming the material into pellets as is conventionally done.
摘要:
In a process for producing propylene copolymer containing about 80 to 99 mol % propylene and about 1 to 20 mol % ethylene and/or an .alpha.-olefin having 4 to 18 carbon atoms using a Ziegler-Natta catalyst, the improvement which comprises said Ziegler-Natta catalyst comprising:(A) titanium trichloride prepared by reducing titanium tetrachloride with an organoaluminum compound and activating the product; and(B) an organoaluminum compound;with the molar ratio of (B)/(A) being about 20 to 100.
摘要:
In a process for producing polypropylene comprising polymerizing propylene in the presence of hydrogen and a catalyst system comprising (A) titanium trichloride obtained by reducing titanium tetrachloride with an organoaluminum compound and reacting the reduced solid with an ether represented by the formula:R.sup.1 -O-R.sup.2wherein R.sup.1 and R.sup.2 are defined hereinbefore, and a halogen compound selected from the group consisting of (i) halogen or interhalogen compounds of the formula, X.sup.1 X.sup.2.sub.a (wherein X.sup.1, X.sup.2 and a are defined hereinbefore), (ii) titanium halides, and (iii) organic halogen compounds, simultaneously or successively and (B) an organoaluminum compound, the improvement which comprises supplying ethylene together with propylene to the polymerization system such that the ethylene concentration in the vapor phase of the system based on the total amount of propylene, ethylene and hydrogen in the vapor phase of the system is 0.15 to 1.5 mol % to obtain a propylene-ethylene copolymer having an ethylene content of from 0.1 to 1.0 wt % is disclosed. The propylene-ethylene copolymer is improved in stretchability.
摘要:
A process for producing a homopolymer of propylene or a copolymer of propylene which comprises polymerizing propylene or a mixture of propylene and another unsaturated hydrocarbon monomer such as ethylene in liquid propylene, in the presence of a catalyst system consisting essentially of (a) an activated titanium compound obtained by reducing titanium tetrachloride with an organic aluminum compound and activating the resulting titanium compound and (b) an organic aluminum compound to produce a polymer slurry, introducing the polymer slurry into an upper part of a counter-current washing zone, such as a washing tower, and counter-currently contacting the polymer slurry with liquid propylene which is introduced into a lower part of the washing zone, whereby the polymer and catalyst residues dissolved in the polymer slurry are removed.