Patent GB-801031-A (GB)
Title: Production of high molecular weight polyethylenes
IPC: D01D1/06
Filed: 1955-01-18
Abstract: A catalyst suitable for the polymerization of ethylene (see Group IV (a)) is formed by mixing an organo-metallic compound of magnesium or zinc with a compound of a Group IVa, Va or VIa metal, including thorium and uranium.  The organo-metallic compounds specified are magnesium and zinc alkyls and aryls, such as the dimethyl, diethyl, dipropyl and dibutyl compounds, and halogen derivatives thereof such as Grignard compounds and the corresponding zinc compounds, e.g. magnesium butyl and propyl chlorides, and magnesium phenyl bromide-these latter compounds preferably being ether-free.  Group IVa, Va and VIa metal compounds disclosed are: the halides, such as the chlorides and bromides; oxyhalides such as the oxychloride; complex halides such as the complex fluorides; freshly precipitated oxides and hydroxides; and organic compounds, such as alkoxides (e.g. titanic acid tetrabutyl ester), acetates, benzoates and acetyl acetonates.  Suitable metals for such compounds are Ti, Zr, Hf, Th, V, U, Nb, Ta, Cr, Mo, and W.  Inert solvents which may be present include pentane, hexane, cyclohexane, tetrahydronaphthalene, decahydronaphthalene, paraffins, diesel oil, benzene, toluene, xylene, dichlorobenzene, chlorinated naphthalene, dibutyl ether, dioxane, and tetrahydrofurane. Catalyst formation is preferably conducted in an inert atmosphere such as nitrogen.  Following polymerization the catalyst may be destroyed with methanol and methanolic hydrochloric acid or steam distillation in the presence of hydrochloric acid.ALSO:Ethylene is polymerized with a catalyst formed by mixing an organo-metallic compound of magnesium or zinc with a compound of a Group IVa, Va or VIa metal, including thorium and uranium. Organometallic compounds specified are magnesium and zinc alkyls and aryls, such as the dimethyl, diethyl, dipropyl and dibutyl compounds, and halogen derivatives thereof such as Grignard compounds and the corresponding zinc compounds, e.g. magnesium butyl and propyl chlorides, and magnesium phenyl bromide; these latter being preferably ether free.  Groups IVa, Va and VIa metal compounds disclosed are: the halides, such as the chlorides and bromides; oxyhalides such as the oxychloride; complex halides such as the complex fluorides; freshly precipitated oxides and hydroxides; and organic compounds, such as alkoxides (e.g. titanic acid tetrabutyl ester), acetates, benzoates and acetyl acetonates.  An inert solvent is preferably used and listed are pentane, hexane, cyclohexane, tetrahydronaphthalene, decahydronaphthalene, paraffins, diesel oil, benzene, toluene, xylene, dichlorobenzene, chlorinated naphthalene, dibutyl ether, dioxane and tetrahydrofurane.  The ethylene may be pure or in admixture with gases, such as ethane and propane, produced in cracking or in the Fischer-Tropsch synthesis.  Catalyst formation and polymerization is preferably conducted in an inert atmosphere. The polymerization process is operable at normal pressures and temperatures and products of molecular weight up to 3,000,000 and of high melting point may be obtained.  The examples illustrate the continuous and intermittent addition of ethylene and the purification of the products/destruction of catalyst with methanol and methanolic hydrochloric acid, or by steam distillation in the presence of hydrochloric acid.  The polyethylenes may be stretched in the cold and applications given are sheets, foils, threads, fibres and filaments.