Basf Aktiengesellschaft

Badische Anilin- & Soda-fabrik Aktiengesellschaft

Friedrich Urban

Oskar Buechner

Hans Gropper

Gottfried Schlichthaerle

Heinz Mueller-Tamm

Gerhard Zeitler

Dieter Oeder

Klaus Steigerwald

Guenther Schweier

Erich Kolk

Hans Schick

Franz G Mietzner

Karl-Heinz Fauth

Ulrich Hartig

Rudolf Herbeck

Heinz Gehrig

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.

Multi-stage isolation of high pressure polyethylene

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.

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.

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.

Manufacture of ethylene polymers in a two-zone tubular reactor at

Ethylene polymers are manufactured by polymerizing ethylene under high pressure at high temperatures in an autoclave reactor. The heat of reaction generated by the polymerization is removed, within the reactor, by a cooling system in which the cooling medium is ethylene; the pressure of the monomer in the cooling system should differ by from 0 to 200 bars from the pressure prevailing in the polymerization system, and the temperature of the monomer on entering the cooling system is at least 40.degree. C. lower than the temperature prevailing in the autoclave. The process permits an increase in the conversion achieved in the polymerization reaction.

Manufacture of ethylene polymers in an autoclave reactor

Unsaturated carboxylic acids are grafted onto copolymers of ethylene and carboxylates. Carboxylic acid containing initiator is caused to diffuse into shaped elements of the copolymers, polymerization then being carried to completion by heating. The products exhibit no fish eyes and are highly suitable for sheet manufacture.

Manufacture of graft copolymers

Ethylene polymers are produced at pressures between 1000 and 4000 atmospheres and temperatures of from 120.degree. to 300.degree. C in a reaction zone having an 1/d ratio of from 10:1 to 20:1 while shear forces act on the reaction mixture. The ethylene is fed continuously and radially to the reaction zone at a velocity of from 2 to 20 m/sec. The average residence time of the reaction mixture in the reaction zone is from 20 to 90 seconds. The products show a broad molecular weight distribution and are particularly advantageous for use as extruded coatings.

Manufacture of ethylene polymers

Process for the manufacture of graft polymers from copolymers of ethylene with vinyl esters, acrylates or methacrylates by grafting an ethylenically unsaturated carboxylic acid thereto in the presence of a free-radical polymerization initiator. Homogeneous graft copolymers are obtained from which sheeting can be made. To this end, the unsaturated carboxylic acid is first caused to diffuse into the copolymer and the mixture is then extruded at temperatures above the crystallite melting point of the ethylene copolymer.

Process for the manufacture of graft polymers

Particulate polymers of ethylene are prepared by polymerization of ethylene or ethylene/.alpha. -monoalkene mixtures in a dry agitated bed (B) of the particulate polymer by means of a Ziegler/Natta catalyst system consisting of (1) a titanium-containing component and (2) an aluminum-containing component, the said components (1) and (2) being separately fed to the bed (B). Component (1) is a particulate reaction product (U) (of) (1.1) a substance of the formula TiCl.sub.3 . (AlCl.sub.3).sub.n where n is a number equal to from 0 to 0.34, and (1.2) a reaction product (R) of phosgene and a substnace (S) obtained from a substance of the formula Mg.sub.6 . Al.sub.2 . (OH).sub.16 . CO.sub.3 . (H.sub.2 O).sub.4 by calcination (heating), provided that (R) has a chlorine content of from 10 to 76% by weight and (U) has been obtained by milling (1.1) and (1.2) together.

Manufacture of particulate homopolymers or copolymers of ethylene

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.

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