SE193558C1 - - Google Patents

Description

Inventors: K Ziegler, H. Breil, E. Holzkamp and H. Martin Priority requested until December 27, 1954 (Federal Republic of Germany). The present invention relates to the production of such plastics as usable, high molecular weight polyethylenes having a molecular weight of over 2000 and preferably more than 10,000. In general, with suitable catalyst concentration according to the invention, it is even possible to obtain polyethylenes with a molecular size, which is higher than that which has hitherto been regarded as the owe limit for the technically available polyethylenes. This limit is approximately at molecular weights of around 50,000, this number being only an indication that solutions of such polyethylenes have a certain viscosity. The calculation of spruce viscosity tables in the present case on the basis of a formula described by Schulz and Blaschke (Journal of Practical Chemistry, Vol. 158 [1911], pp. 130-135, formula 5b, p. 132), the latter special viscosity corrected according to Fox, Fox and Flory, J. Am. Chem. Soc. 73 (1951), p. 1901. From this granular viscosity the above-mentioned average molecular weight 50,000 was calculated with the aid of that of R. Houvvink, Journal for Practical Chemistry, Neue Folge 1957 (1940), p. 15-16, described the formula (5) in a slightly modified form MG = k • (0 ° whereby for the new plastics shaved with the cone, the stants k = 2.51 • 4 and a = 1.285. definition of molecular weight, polyethylene having a molecular weight up to 3000000 and above can be obtained with suitable catalyst combination and concentration according to the invention.

The polyethylenes obtained according to the invention are, as stated above, extremely high molecular weight. They have a softening or melting point above 130 ° C. Furthermore, they are completely insoluble in all solvents at room temperature. Dc low molecular weight products (up to a molecular weight of about 100000) dissolve partially • first over 70 ° C, while the high molecular weight (with a molecular weight Over 100000) partially dissolve only above 100 ° C. The temperature resistance of the new products is greater than, wear kanda polyethylene. When the new products are heated to a temperature above 250 ° C, they retain their white color, while the color of a hand product changes to gray between 200 and 250 ° C. The resistance of the new products to the oxidizing effect of atmospheric oxygen is also greater than in the previous can pro dukters.

The new polyethylenes have a h5g which is unusual for high molecular weight carbonates. The crystallinity remains unchanged at Over 100 ° C and only disappears near the softening point. As can be seen from X-ray diagrams, the degree of crystallinity in general states about 80% and Or in many cases higher. Also store the cairn kunita of course occur.

The polyethylenes produced according to the invention have a completely linear structure and practically no branches. Out of 100 methylene groups, the polyethylenes contain at most 3 methyl groups, but in general the number of methyl groups is still much lower and at most 0.03 per hundred methylene groups, in many cases even less than 0.01 per hundred methylene groups. The infrared spectra of the products produced according to the invention show, in contrast to those of previously known polyethylenes which have some characteristic methyl bands.

The tear hall strength amounts to a maximum of 100 kp / cm2 and in many cases to 8 over 200 kp / cm2. The tensile strength in the unstretched state amounts to more than 200 kp / cm2 and up to 3000 kp / cm2 is drawn after stretching oriented foils.

The products can directly, e.g. between heated plates, processed into clearly transparent, elastic and flexible plates or foils. They were also suitable for processing by extrusion or injection molding. The products are stretchable in the cold and in the cold state & can in this way be drawn into ribbons, threads or fibers with high elasticity and half-strength, which has never before been possible with polyethylene made otherwise. The products already show a remarkable tendency for fiber formation during processing. In the small state, they can be spun into threads according to the methods customary for spinning superpolyamide fibers. The tricycles made from the new polyethylenes can be used as such for industrial purposes.

Swedish patent 159 804 describes a process for the preparation of such 118 g molecular, plastic-like polyethylenes of this kind, according to which ethylene is brought into contact with catalysts which consist of mixtures of aluminum trialkyls with compounds of transition metals in groups IV-VI of the periodic table. incl. thorium and uranium. Other metals cannot be used in this preparation of high molecular weight ethylene polymers of plastic nature.

Belgian patent 534 888 describes the production of high molecular weight, plastic-like polyethylenes by contacting gaseous ethylene with catalysts, which consist of mixtures of organic compounds of magnesium and / or zinc and compounds of Group IV-VI transition metals in the Periodic Table incl. . thorium and uranium, under conditions in which the metal compounds are neither reduced to free metal nor ionized.

The invention thus relates to a process for the preparation of high-use, high-grade polyethylenes which can be used as plastics by polymerizing ethylene in the presence of a catalyst, the silk consisting of organic metal compounds and of transition metal compounds from groups IV to VI of the Periodic Table. The distinguishing feature of the process is that, even with such a component in such catalysts, organic compounds of aluminum, magnesium diet zinc, known as organic metal compound in the catalyst, use alkali metal alkyls or complex compounds of either organic compounds of aluminum and magnesium or aluminum and zinc or of organic compounds of aluminum, magnesium or zinc with alkali metal alkyls or alkali metal hydrides.

It is already possible to polymerize liquid ethylene at a temperature below 9.6 ° C at pressurized pressure, whereby alkali metal alkyls form a component in the catalyst combinations. These organometallic organometallic compounds are used in conjunction with Group 8 and Group 1b metals of the Periodic Table. In cases where cla salts of these metals are used, such conditions are chosen, that free metals Midas. According to an animated embodiment of this process, in principle various combinations are used as catalysts, namely peroxides in the presence of ions of silver, titanium, vanadium, crown, manganese, jam, cobalt, nickel and copper. The ionic form of the metals used is of crucial importance.

The present process is by far the best process with respect to the action of the catalysts on the rate at which polymerization to high molecular weight polyethylenes takes place. As alkali metal organic compounds according to the invention, alkali metal alkyls can be used, e.g. lithium, sodium or potassium methyl, -ethyl, -propyl, -benzyl, -isobutyl or Oxen higher alkali metal alkyls. However, it is also possible to use complex compounds of these alkali metal alkyls with organic compounds of aluminum, magnesium or zinc, for example according to the Swedish patent 159 804 and the Belgian patent specification 534 792, e.g. with aluminum trialkyls or alkylaluminum halides. Finally, complex compounds of alkali metal hydrides with organic compounds of aluminum, magnesium or zinc can also be used. According to the invention, for example, associations with. the formulas Na [Al (CA) 4], Li [Al (C118) 2112], Na [Al (CO11r,) 3H] and Mg [Al (C21-1) 4] 2.

The described organometallic compounds are used according to the invention together with compounds of transition metals in groups 4-6 of the periodic table, incl. thorium and uranium. For example, compounds of titanium, zirconium, hafnium, thorium, uranium, vanadium, niobium, tantalum, chromium, molybdenum and tungsten can be used. Salts of titanium, zirconium or chromium were particularly suitable. As compounds of the aforementioned metals lamp halides, e.g. chlorides or bromides, oxyhalides, eg oxychlorides, complex halides, e.g. complex: fluorides, newly precipitated oxides or hydroxides or organic compounds, e.g. alcoholate, acetate, benzoate or acetylacetonate. A particularly effective catalyst according to the invention is obtained by mixing, for example, titanium or zirconium tetrachloride, oxychloride or acetylacetone with organic alkali compounds. One. The catalyst transfers very quickly ethylene to high molecular weight polyethylene even at pressures below 100 atm and at one. temperature below 100 ° C.

In addition, the known high-pressure processes have the disadvantage that only a relatively small amount, namely about 15-20%, of the supplied ethylene is converted to polyethylene during each test run. According to the invention, on the other hand, a very significant part of the amount of ethylene supplied during each test run. Furthermore, the ethylene used according to the invention need not be as pure as in the previous known efficiencies.

The polymerization process of the invention can be carried out at a comparatively applied pressure of about 10 lbs. atm. You can also work at a pressure below 10 atm. even at atmospheric pressure or reduced pressure. Of course, the effect of the new catalysts on the ethylene remains basically unchanged, when the pressure is raised to an arbitrary from a technical point of view still possible high level.

The new polymerization catalysts are already active at room temperature or below. It is suitable to work at elevated temperature, especially above 50 ° C. On the other hand, it is not suitable to work at a temperature above 250 ° C, since the catalysts are significantly subdivided at this temperature.

Instead of pure ethylene, in carrying out the present process, ethylene-containing gas mixtures can also be used, such as gags, which are formed by cracking of the matt carbonates, e.g. ethane or propane, or of petroleum and its fractions, or by appropriately conducted Fischer-Tropsch syntheses and which may have liberated other olefins.

Harvid and Oxen in other cases may be obliged to work in the presence of solvents. However, these solvents must not promote a dissociation of the metal compounds. Accordingly, water, methanol or other solvents with a high dielectric constant are not used. In addition, such solvents would enlarge the organic alkali compounds. Inert solvents must be used, in which the metal salts are insoluble and do not dissociate. as suitable solvent solvents of the delta type called aliphatic and hydroaromatic hydrocarbons, i.e. pentane, hexane, cyclohexane, tetrahydronaphthalene, decahydronaphthalene, higher, reaction temperature liquid paraffins, aromatic hydrocarbons, e.g. benzene or xylene, halogenated aromatic hydrocarbons, e.g. o-dichlorobenzene or chlorinated naphthalenes, ethers, e.g. dibutyl ether, dioxane or tetrahydride ofuran.

The solvent is used to such an extent that stirring of the reaction mixture overnight and evenly is possible at the end of the reaction. In general, the reaction mixture can be stirred even when it contains 10% polyethylene at the end of the reaction. According to what has been stated above, there are only limits with regard to the economic implementation of the procedure in practice.

The invention is further illustrated by the following examples.

Example 1. Of 12 g of sodium aluminum tetramethyl [prepared on the same salt as nat. aluminum aluminum tetraethyl according to the Journal of Organic Chemistry, 5, (1940), p. 111] was prepared with 80 ml of hexane a fine suspension by one hour maiming in a ball shaker without air conditioning. The suspension was then continued dropwise with stirring with 4 g of titanium tetrachloride in 20 ml of hexane, whereby the suspension became black and a gas evolved. This black, fine suspension was then introduced into a 200 ml autoclave, whereupon 40 g of ethylene were pressed and the autoclave was heated to 100 ° C with shaking. The pressure then rose to one. starting from 50 to 80 atm and foil mom 20 hours to 25 .atm. After cooling, 7 g of ethylene were removed. The autoclave contained 30 g of a catalyst black grass-colored, hexane-finely divided polyethylene, which for purification was freed from the reading agent by filtration and then boiled with methanolic hydrochloric acid. After dilution with methanol and acetone and drying at 80-100 ° C, a pure white, finely powdered product is obtained.

Example 2. 100 g of a mixture of cracked olefins obtained from crackle olefins with an average composition, corresponding to aluminum tridodecyl, were dissolved under a nitrogen atmosphere in 200 ml of dehydrated FischerTropsch diesel oil with a boiling point of 200230 DEG C. and heated with intensive stirring with sodium g to 130 DEG-150 DEG C. The lysis became dark colored p0. due to secreted aluminum and because some of the sodium went into solution. The aluminum was lumped together with slow cooling of the mixture to about 90 ° C with the excess sodium, whereby the solution became clear and could be freed from the solid precipitate by decantation. In contrast to the sodium aluminum tetramethyl of Example 1, the complex compound having the average composition Na (Cl 2 H) 4A1 remained dissolved in the diesel oil. 50 ml portions of the solution were then used for the following experiments: a) To 50 ml of the solution described above was added 600 ml of dehydrated Fischer-Tropsch diesel oil, after which the resulting solution was introduced into a glass vessel with a volume of 1 liter. Then a solution of 1 g of titanium tetrachloride in 50 ml of diesel oil was introduced dropwise with stirring and without air, whereby the solution became black while precipitating a finely divided solution. Ethylene was then started with stirring at 70-90 ° C and polymerized the 1 - - reaction vessel to polyethylene radar and bundles, which were slowly separated from the solvent. The ethylene supply was controlled so that the non-polymerized ethylene was only weakly beaded through the blast furnace in the outlet line. After four minutes, the experiment was stopped and the polyethylene formed was worked up as in Example 1. 75 g of a pure white, very finely powdered polyethylene were obtained. 50 ml of the solution described above was continued with 3 g of thorium IV acetylacetonate and the yellow solution was diluted with 30 ml of dehydrated Fischer-Tropsch diesel oil. The whole solution was now introduced under nitrogen into a 200 ml autoclave and 33 g of ethylene were pressed. The autoclave is heated with shaking to 90 ° C, whereby the pressure rises to 50 atm. After 15 hours, the pressure had dropped to 15 atm. After cooling and draining the joke polymerized ethylene (8 g in total), 22 g of hexane-suspended polyethylene, suspended in hexane, were worked up in the autoclave and worked up into the usual salt described in Example 1. 50 ml of solution of the type described was diluted with 350 ml of dehydrated FischerTropsch diesel oil and intensively ground for two hours in a ball shaker with 2 g of zirconium tetrachloride. The resulting dark brown suspension was introduced under nitrogen into a 1 liter volumetric crucible and heated under a constant ethylene pressure of 10 atm to 90 ° C. After 10 hours, the experiment was stopped and the excess ethylene was removed. After separating the diesel oil, the polyethylene remaining in the autoclave was worked up on ordinary salt. 85 g of pure white, finely powdered polyethylene are obtained. 50 ml of complex salt solution was continued with 150 ml of dehydrated Fischer-Tropseh diesel oil and 1.5 g of chromium-III bromide and ground intensively for two hours in a ball shaker. The black suspension formed was then continued under nitrogen in a 500 ml autoclave with 65 g of ethylene. The initial pressure was 45 atm and rose to 100 atm when heated to 100 ° C with shaking. After 40 hours, the pressure had dropped to 25 atm. The autoclave was allowed to cool and 11 g of ethylene were blown out. In the autoclave remained a grin of ethylene polymers finely suspended in diesel oil, which after customary purification gay g of a white, fine polyethylene powder.

Example 3. 29.3 g of aluminum tri-n-butyl, dissolved in 35 ml of hexane, were added while stirring with 13.4 ml of an 11-N-sodium hydride suspension in hexane. Upon heating the mixture, the sodium hydride was quantitatively dissolved. The resulting solution, which remained clear on cooling and from which no crystals precipitated, was liberated from hexane by evaporation in vacuo to give the crystallized complex sodium sodium tributyl hydride. 10.5 g of the thus prepared sodium aluminum tributyl hydride were dissolved in 250 ml of hexane, after which a solution of 4 g of titanium tetrachloride in 20 ml of hexane was added dropwise. The solution was then blackened. The contact mixture was stirred for 30 minutes at 40-60 ° C and diluted with 2.2 liters of Fischer-Tropsch diesel oil. Ethylene was introduced into the mixture and after a reaction time of 60 hours at 60-90 ° C, a coarse suspension of polyethylene formed in the Fischer-Tropsch diesel oil had formed. The reaction mixture was freed from the suspending agent by suction and the polyethylene was treated for two hours with hutanolic hydrochloric acid at 90-100 ° C for purification, releasing the catalyst residues containing the polyethylene. The product was then washed with methanol and acetone and dried to give 215 g of polyethylene recovered.

Example 4. In 500 ml of boiling anhydrous toluene, 250 ml of a 2-N ethylmagnesium chloride solution in ether were introduced dropwise with vigorous stirring. The Grignard compound then formed in the form of a white powder, while the ether distilled off. After evaporation of the toluene in vacuo, the ether-free grignard compound is obtained. 9 g of the thus prepared ethereal ethylmagnesium chloride were heated for six hours together with 11.5 g of aluminum triethyl and 25 ml of hexane in a 200 ml autoclave under strong shaking at a temperature of 100 ° C. After cooling, evaporation of the centrifuged hexane solution was obtained. , 5 g of the complex compound magnesium-dialuminum octetyl in the form of a thick oil (composition: 7.6% Mg, 17.0% Al; calculated for IvIg [Al (C2H2) 4] 2: Mg 7.84%, Al17 The obtained magnesium dialuminum-octetyl (7.5 g) was dissolved in 100 ml of hexane and continued dropwise at 60 DEG-80 DEG C., with vigorous stirring with a solution of 4.5 g of titanium tetraloride in 50 ml of hexane. to a 500 ml autoclave, after which 75 g of ethylene were pressed in and the autoclave was heated to 100 ° C with shaking. The pressure dropped within 10 hours to 5 atoms. After cooling, 5 g of ethylene were blown out. The autoclave contained a batch of ethylene polymers suspended in hexane. as after customary purification gay 66 g of one white polyethylene powder.

Example 5. 6 g of zinc diethyl [prepared according to Ann. 152, p. 321 (1869) described procedure], dissolved in 50 ml of heptane, was continued. dropwise with vigorous stirring and under nitrogen with a solution of 5.8 g of aluminum triethyl in 50 ml of heptane, after which the mixture was heated for one hour to the boiling point of the solvent. After cooling, the mixture was ground, a. together with 4 g of zirconium tetrachloride two hours in a ball shaker, warp it. formed, the black suspension under nitrogen. was introduced into a 500 ml autoclave, 6 g of ethylene was pressed in and the autoclave was shaken for 15 hours. at 90 ° C, the pressure foil to 22 atm. After cooling, 9 g of ethylene are blown out. Autoclaves in-. neholl a large suspension ay polyethylene i. - - heptane, which. after usual purification gay 52 g white polyethylene.

Example 6. 50 g of aluminum trihexyl was dissolved under nitrogen in a 200 ml of hydrogenated Fischer-Tropsch diesel oil with a boiling point of 200-250 ° C and heated with intensive stirring with 10 g of potassium to 120-130 ° C. color and some of the potassium went into solution. Upon slow cooling, the aluminum precipitated with the excess potassium, whereby the solution became clear and could be decanted from the solid base. The complex compound with, composition KA1 (C61-113) 4 was dissolved in the diesel oil.

To 50 ml of the solution prepared at the same time was added 600 ml of hydrogenated FischerTropseh diesel oil, after which the entire Risningen was introduced into a 1 liter glass vessel. A rhyme of 2.5 g of titanium tetrachloride in 50 ml of diesel oil was then introduced dropwise into the vessel during purification and without air, the solution taking on a black color. Ethylene was started under heavy masonry at 60-90 ° C. After 30 minutes, the reaction mixture was grotty because the ethylene had polymerized to polyethylene. The reaction mixture was worked up as in Example 1 to give 153 g of a pure white, very finely powdered polyethylene.

Example 7. 17.5 g of one of J. A. Wanklyn, Ann. 108 (1858), p. 67, prepared complex compound, sodium zinc triethyl, was ground, with 4.4 g of vanadium oxychloride and 50 ml of hexane for four hours in a ball shaker. The resulting dark brown-black suspension was filled under nitrogen into a 200 ml autoclave, after which 45 g of ethylene were pressed. The autoclave was heated with shaking to 100 ° C, the pressure rising to 85-90 atm. After ten hours, the attempt is interrupted. Or cooling, draining the excess ethylene and purifying the polyethylene formed by filtration and boiling with methanolic hydrochloric acid gave 8 g of a powdery, pure white polyethylene.

Example 8. 10 ml of a 6-molar lithium butyl solution in benzene was ground for 2 hours together with 1 g of zirconium tetrachloride and 70 ml of hexane in a ball shaker while excluding air. The resulting black-brown suspension was introduced under nitrogen into a 200 ml autoclave, after which 40 g of ethylene were pressed. The autoclave was heated with shaking to 100-110 ° C, the pressure rising to 80 atm. Already after four hours the pressure had dropped to 25 atm and after another 20 hours to 10 atm. After cooling, 3 g of ethylene were removed. The autoclave contained a thick layer of polyethylene in the hexane, which was graphitized with catalyst residues. After filtration, the polyethylene was boiled for purification with methanolic hydrochloric acid, the catalyst residues containing the polyethylene being removed by dissolution. The product was washed with methanol and acetone to separate residual hydrochloric acid. 35 g of powdered, pure white polyethylene are obtained in this case. Instead of zirconium tetrachloride, a corresponding amount of titanium tetrachloride, thorium IV acetylacetonate or chromium III chloride can also be used, the reaction proceeding to analogous salt.

Example 9. 20 ml of a 6 molar lithium butyl solution in benzene was mixed together with 2.4 g of aluminum triethyl and 80 ml of benzene. The mixture was continued at room temperature with a solution of 2 g of vanadium tetrachloride 100 ml of benzene Mom for half an hour. The catalyst mixture thus prepared was diluted with 2 liters of benzene and, while stirring at 40 DEG C., ethylene was started at normal pressure. After 2 hours of polymerization, 76 g of polyethylene had formed. To remove the polyethylene catalyst, the product was stirred with butanol at 70-80 ° C for 30 minutes, after which the product was washed with methanol and acetone and dried.

Claims (1)

1. Patent claim: Process for the preparation of high-molecular-weight polyethylenes by the polymerization of ethylene in the presence of a catalyst, which consists of organometallic compounds and compounds of transfer metals Iran Group IV to Vii of the Periodic Table, characterized in that together with such a component such catalysts Hilda organic compounds of aluminum, magnesium or zinc, as organic metal compound in the catalyst use alkali metal alkyls or complex compounds either of organic compounds of aluminum and magnesium or aluminum and zinc or of organic compounds of aluminum, magnesium or zinc with alkali metal alkyls or alkali metal hydrides. Request publications: Patents Iran UK 587 475, 682 420.