Abstract: Propylene/ethylene polymers are prepared by a process in which, in each case in the presence of hydrogen and by means of gas phase polymerization, first (A), in a first polymerization zone, propylene is homopolymerized, and the resulting propylene homopolymer is introduced into (B) a second polymerization zone, where a mixture of propylene and ethylene is then polymerized with the reaction product obtained in (A). In this process, ethylene is homopolymerized in a further polymerization zone (C), likewise by gas phase polymerization, with certain provisos, and the resulting reaction product is likewise fed to the second polymerization zone (B).

Abstract: Copolymers of ethylene with vinyl esters are prepared in a continuously operated tubular polymerization system at high pressure and temperatures by feeding a mixture of ethylene, vinyl ester, initiator and, if appropriate, regulant into the polymerization system in the form of a mainstream at the inlet point thereof and at the same time through two or more secondary streams downstream of the inlet point, secondary streams (I) being metered in at points where the reaction temperature has just exceeded a maximum temperature due to the heat of polymerization and secondary streams (II) at points which, relative to the direction of flow of the ethylene, are upstream of the feed points of secondary streams (I) and upstream of the respective maximum temperature.

Abstract: Copolymers of ethylene with acrylates or solutions of free acrylic acid in acrylates are prepared in a continuously operated tubular polymerization system at high pressures and temperatures by feeding a mixture of ethylene, acrylate, initiator and, if appropriate, regulant into the polymerization system in the form of a main stream at the inlet point thereof and at the same time through two or more secondary streams, secondary streams (I) being metered in at points where the reaction temperature has just exceeded a maximum temperature due to the heat of polymerization and secondary streams (II) at points which, relative to the direction of flow of the ethylene, are upstream of the feed points of secondary streams (I) and upstream of the respective maximum temperature.

Abstract: A process for the continuous production of an ethylene copolymer by compressing a mixture of ethylene and comonomer in a pre-compressor and a post-compressor, copolymerizing the mixture in a polymerization zone at a high temperature and high pressure, transferring the reaction mixture into a high pressure product isolation zone, from there into a low pressure product isolation zone and thereafter into a discharge extruder, and recycling the greater part of the unconverted monomer into the polymerization process and passing a small part of the unconverted gas into a low temperature isolation zone, in which process a small part of the gas recycled from the high pressure product isolation zone is passed into the low temperature isolation zone, which is preferably under a pressure of from 10 to 30 bar and at from -10.degree. to -50.degree. C., and all the gas taken off the low pressure product isolation zone is fed to the pre-compressor.

Abstract: A continuous process for the manufacture of ethylene copolymers under high pressure and at high temperature in a polymerization zone, with transfer of the reaction mixture into a high pressure product isolation zone and from there into a low pressure product isolation zone, and recycling of the unconverted gas from the high pressure product isolation zone into the polymerization zone and from the low pressure product isolation zone into a low temperature separator, from where the comonomer separated off is recycled to the polymerization process, while the ethylene is discharged as off-gas. The gas taken off the low pressure product isolation zone is preferably compressed to from 10 to 20 bar and cooled to from -10.degree. to -30.degree. C. before it is fed into the low temperature separator. There is a substantial improvement in the efficiency of separating off the comonomer.

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 high pressure polymerization of ethylene at elevated temperatures in a polymerization zone followed by transfer of the reaction mixture, through a cooling zone, into the separation zone. In this process, the pressure at the cooling zone outlet is periodically reduced briefly, at recurring intervals, these brief pressure reductions being independent of the pressure reductions in the polymerization zone. Using this process, the conversion in the polymerization unit can be increased and a more homogeneous ethylene polymer can be obtained.

Abstract: The invention relates to a process for rapidly letting-down the pressure in continuous high pressure polymerization systems for the polymerization of ethylene. In this process, the let-down hot reaction mixture is passed into an expansion vessel in such a way that the jet of let-down hot reaction mixture issuing from the let-down line is led into the partially water-filled expansion vessel at an angle of from 0.degree. to 45.degree. to the water surface, so that the jet does not enter below the surface but must touch or strike it. The method described makes it possible to let the mixture down partially and thus to slow down the decomposition in the case of explosive decomposition reactions occurring in the polymerization system.

Abstract: A process for the manufacture of ethylene polymers by high pressure polymerization of ethylene, if desired mixed with other compounds copolymerizable with ethylene, and isolation of the reaction product in a multi-stage isolation zone. The molecular weight of the ethylene polymer can be varied by varying the temperature prevailing in the isolation zone. The isolation zone preferably consists of two stages, with a higher pressure prevailing in the first stage than in the second stage.

Abstract: The removal of ethylene from gases which contain the ethylene in a concentration of not more than 1.8% by volume by means of a supported palladium catalyst which contains from 0.05 to 10 g of palladium per liter of an inert inorganic carrier, the oxidation reaction being started at a temperature of from 180.degree. to 200.degree. C.

Abstract: A process for the manufacture of copolymers of ethylene with n-butyl acrylate in a polymerization zone at pressures above 800 atmospheres and at from 150.degree. to 350.degree. C, wherein the reaction mixture obtained is transferred, via a cooling zone which is at a pressure below 500 atmospheres and at from 150.degree. to 250.degree. C, into the high pressure product isolation zone, the mean residence time of the reaction mixture in the two zones being from 2 to 10 minutes. A copolymer which gives good films is obtained.

Abstract: A process for the manufacture of ethylene polymers by homopolymerization and copolymerization of ethylene at pressures of from 500 to 5,000 bars and at from 50.degree. to 450.degree. C, with subsequent isolation of the polymers in high pressure product isolation zones and low pressure product isolation zones. The various parallel product isolation zones are at different temperatures, and the mean product residence times in the zones may be identical or different. Very different products, in amounts which can be chosen according to requirements, and with mutually independent polymer properties, can be obtained using only one high pressure polymerization system.

Abstract: A process for the manufacture of ethylene polymers by high pressure polymerization of ethylene, if desired mixed with other compounds copolymerizable with ethylene, and isolation of the reaction product in a multi-stage isolation zone. The molecular weight of the ethylene polymer can be varied by varying the mean product residence time in the isolation zone. The isolation zone preferably consists of two stages, with a higher pressure prevailing in the first stage than in the second stage.

Abstract: Ethylene polymers are manufactured in a tubular reactor under high pressure and at high temperatures in the presence of polymerization initiators. The polymerization is carried out in two different zones of the reactor, a mixture of ethylene, oxygen and regulator being fed into the first zone and a co-initiator having a half-life temperature, measured in benzene, of above 140.degree. C being additionally fed into the second zone. The co-initiator may be a peroxide or a hydroperoxide. The melt index, or the haze and gloss of a film produced from the resulting ethylene polymer, can be varied advantageously through the choice of the co-initiator.

Abstract: A process for the manufacture of copolymers of ethylene with vinyl acetate at pressures above 800 atmospheres and at from 150.degree. to 350.degree. C, using mean residence times of up to at most 100 seconds. The reaction mixture obtained from the polymerization is kept for from 2 to 10 minutes at from 150.degree. to 250.degree. C under a pressure below 500 atmospheres. Homogeneous ethylene/vinyl acetate copolymers are obtained without the formation of substantial amounts of free acetic acid by decomposition of the vinyl acetate.

Abstract: Non-tacky molding compositions containing mixtures of bitumen, olefin copolymers and substituted aromatic compounds having at least one functional group, such as dimethyl terephthalate and phthalonitrile. Molding compositions comprising the mixtures of the invention are suitable for use as anticorrosive coatings for the manufacture of elastic non-corrosive bandages for pipelines or for the manufacture of roofing materials.

Abstract: A process for coating moldings of plastics which tend to stick together at room temperature by applying solutions containing a nonadhesive resin of (1) a copolymer of at least one member of the group consisting of styrene and methylstyrene and a monoester of at least one member of the group consisting of maleic and fumaric acid or (2) a reaction product of at least one member of the group consisting of cyclohexanone and methylcyclohexanone with formaldehyde or acetaldehyde, said non-adhesive resin having a monoscope yield point or more than 80.degree.C. and a ball indentation hardness of from 310 to 800 kp/cm.sup.2 at 10 seconds and thereafter evaporating the solvent at a temperature which is lower than the softening point of the material to be coated.

Abstract: Production of a homogeneous mixture of plastics materials in powder form by subjecting a molten inhomogeneous mixture of two or more plastics to a maximum shear velocity of from 10.sup.4 to 10.sup.8 sec.sup.-.sup.1 for from 10.sup..sup.-2 to 10.sup..sup.-6 seconds; the pulverulent mixtures obtained are used in rotary sintering and injection molding.