DE2755192A1 - Powdered polyolefin prodn. using catalysts contg. vanadium cpds. - reacted with and activated by organo-aluminium cpds. - Google Patents

Abstract

Powdered polyolefin having high apparents density, good fluidity, an ave. particle size diameter of up to 100 mu m and being almost free from very fine particles, are obtd. by polymerising ethylene opt. admixed with other 1-olefines, in the presence of H2, in inert liq. hydrocarbons at 50-95 degrees C 10-100 bars, pref. 20-60 bars pressure, in a continuous or discontinuous process using Ziegler catalysts. The catalysts are prepd. in the inert liq. hydrocarbon by reacting vanadyl cpds. contg. Cl atoms and alkoxy gp. with organo-Al cpds., sepg. the insoluble reaction prod. and activating with any organo-Al cpd. The powdered polyolefins obtd. i.e. polyethylene, copolymers of ethylene and propylene and/or butylene-(1) have apparent densities of 0.420-0.550 g/ml, are almost free from fine particles forming dust and are partic. suitable for injection and extrusion moulding e.g. tubes, sheets, hollow bodies etc. The molten prod. because of its compact granular structure is almost free from bubbles. The catalyst has long life and high productivity.

Description

Process for the production of powdered polyolefins

with high bulk densities (addendum to patent application P 27 00 566.9 and additional patent application P 27 21 377.0) Description and examples The main patent ... (patent application P 27 00 566.9) relates to the production of powdery Polyolefins by polymerization of ethylene or its copolymerization with others t-olefins according to the ZIEGLER process, the inventively prepared, pulverulent polyolefins are characterized by the fact that they are suitable for processing too Molded parts with the help of the machines commonly used for plastics processing such as extruders or injection molding machines are particularly suitable.

Subject of the main patent ... (patent application P 27 00 566.9) The invention described is a process for the production of powdered polyolefins with high bulk densities, good flowability, medium grain diameters up to 1,000 and practically no fine grains due to the polymerization of ethylene, if necessary in a mixture with other 8-olefins and in the presence of hydrogen, in inert liquid hydrocarbons at temperatures between 50 0c and about 95 0C and Pressures of 10 to 100 bar, preferably 20 to 60 bar, after discontinuous or continuous process using ZIEGLER catalysts, manufactured in inert liquid hydrocarbons by reacting chlorine- and alkoxy-containing Vanadyl (V) compounds with organoaluminum compounds, separation of the insoluble Reaction product and activation with any organoaluminum compounds, preferably with trialkylaluminum of the formula A1113, in which R is hydrocarbon radicals with 2 to 8 carbon atoms means, characterized in that (1) is the vanadyl (V) compound a reaction product of vanadyl (V) chloride and a vanadyl (V) alcoholate in molar ratios from 1 to 2 to 2 to 1 and (2) as an organoaluminum compound for reduction Ethyl aluminum dichloride and / or diethyl aluminum chloride in molar ratios of Aluminum to vanadium compounds from 1 to 1 to 3 to 1 is used, where (3) the implementation of the vanadium compounds with the organoaluminum compounds is carried out with stirring with specific stirring capacities of 0.1 to 20,000 Watt / m3, preferably 1 to 5,000 watt / m3.

According to additional patent ... (additional patent application P 27 21 377.0) for activation, alkyl aluminum sesquichloride and / or alkyl aluminum dichloride, preferably the commercially available ethylaluminum compounds are used. While using of trialkylaluminum compounds, depending on the composition of the catalyst, to form polymers leads with more or less broad molecular weight distributions, show the after Process of the additional patent (additional patent application P ...) produced polymers narrow molecular weight distributions.

While the according to the main patent ... (patent application P 27 00 566.9) for the production of vanadium containing insoluble in liquid hydrocarbons Catalyst component used vanadyl (V) compound from a reaction product of vanadyl (V) chloride and a vanadyl (V) alcohol in molar ratios of 1 to 2 to 2 to 1 exists, has now been a further development of the subject matter of the invention found that instead of the reaction product mentioned there is also a reaction product of vanadyl (V) chloride with an alcohol, preferably ethanol, propanol (l) or Butanol- (l) in molar ratios of vanadyl (V) chloride to alcohol from 1 to 2 to 1 to 1, preferably about 1 to 1.5, used in a liquid hydrocarbon can be.

The invention therefore provides a process for the production of powdery polyolefins with high bulk densities, good flowability, medium Grain diameters of up to 1,000 μm and practically no fine grain fraction due to polymerisation of ethylene, optionally in a mixture with other olefins and in the presence of hydrogen, in inert liquid hydrocarbons by reacting mixtures from vanadyl (V) chloride and vanadyl (V) alcoholate in molar ratios from 1 to 2 to 2 to 1 with ethyl aluminum dichloride and / or diethyl aluminum chloride in molar ratios from aluminum to vanadium compounds from 1 to 1 to 3 to 1 while stirring with specific Stirring capacities of 0.1 to 20,000 watts / m3, preferably 1 to 5,000 watts / m3, separation of the insoluble reaction product and activation with organoaluminum compounds according to the main patent (patent application P 27 00 566.9) and the additional patent ... (patent application P 27 21 377.0), which is characterized in that instead of mixtures from vanadyl (V) chloride and vanadyl (V) alcoholate in molar ratios from 1 to 2 to 2 to 1 a reaction product of vanadyl (V) chloride with an alcohol, preferably Ethanol, propanol- (l), butanol- (l), used in molar ratios from 1 to 2 to 1 to 1 will.

The one produced according to the invention in liquid hydrocarbons insoluble, vanadium-containing catalyst component can be used with both halogen-free as well as halogen-containing organoaluminum compounds are activated. In all cases the polymerization of ethylene gives among those given above Conditions polymer powder of excellent quality in terms of flowability, Bulk density and freedom from dust. When using halogen-free organoaluminum Compounds such as trialkylaluminum for activating the vanadium according to the invention containing catalyst component gives polymers with a broad molecular weight distribution, which are particularly suitable for processing according to the extrusion process into films, sheets, llohlkörllern, pipes and profiles are particularly suitable. When using dialogs containing organoaluminum compounds such as ethylaluminum sesquichloride and or Ethyl aluminum dichloride, on the other hand, gives polymers with a narrow molecular weight distribution, as they are particularly advantageous for the production of injection molded articles.

The present invention therefore enables the main patent ... (patent application P 27 00 566.9) and in the additional patent ... (patent application P 27 21 377.0) described technical progress thereby to particularly advantageous Way to achieve that on the complex production of chlorine-free vanadyl (V) alcoholates can be dispensed with and instead of a reaction product of vanadyl (V) alcoholate with vanadyl (V) chloride, a chlorine-containing reaction mixture which is easily obtainable of vanadyl (V) chloride used with an alcohol. The implementation of the vanadyl (V) chloride with the alcohol is expediently in an inert liquid hydrocarbon Room temperature or made at elevated temperature, depending on the reaction conditions more or less hydrogen chloride escapes.

For example, when using a liquid inert hydrocarbon with the boiling range from about 60 to 80 ° C. when heated under reflux for several hours the hydrogen chloride released during the reaction of the vanadyl (V) chloride with the alcohol almost quantitatively driven out. For the method according to the invention, however, is the The proportion of hydrogen chloride remaining in the reaction mixture is not essential Meaning. The alcohols are generally saturated, monohydric alcohols with straight-chain alcohols or branched alkyl radicals. The best results in terms of a possible high catalyst activity with primary, monohydric, straight-chain alcohols achieved. With regard to high bulk densities, freedom from dust and good flowability the polymer powder is obtained when using ethanol, propanol (l) and butanol (l) particularly good results. If the carbon number of the alcohols is greater than four, one obtains with increasing chain length, increasingly finer powders that are required for processing to plastic prefabricated parts are less desirable.

Example 1 a) Catalyst preparation 346.6 g (2 mol) of vanadyl (V) chloride and 180.3 g (3 mol) of propanol- (l) were together in 1.59 l of a hexane cut 63/80 OC heated under reflux for 2 hours, whereupon hydrogen chloride escapes. Thereafter, this mixture and a solution of 507.8 g (4 moles) of ethylaluminum dichloride in 2.25 1 of the Rex gate 63/80 DC synchronously in the course of 2 hours to 2 1 des Hexane cut at 28 ° C under nitrogen and while stirring with a paddle stirrer and a specific stirring power of 95 watt / m3. The suspension obtained was then refluxed for a further hour and with the same specific Stirring power stirred.

After cooling, the solid was separated off and five times with 5 l each of the hexane cut was washed.

b) Polymerization of Ethylene The vanadium catalyst described in Example la was placed in a 750-1 stirred tank for the continuous polymerization of Ethylene used. The polymerization of ethylene took place in a suspension from a hexane cut in the boiling point between 63 OC and 80 DC and powdery Polyethylene and catalyst. The level in the polymerization tank was on 300 1 set; as the mean residence time of the catalyst in the polymerization vessel 2 hours were chosen.

The polymerization was carried out at a temperature of 75 DC. The ethylene partial pressure in the gas space of the polymerization vessel was 34.1 bar. Hydrogen was used to regulate the average molecular weight; the hydrogen partial pressure in the gas space of the polymerization reactor was 0.9 bar. As a cocatalyst for activation triisobutylaluminum was used. Catalyst and cocatalyst were in one Agitator tank diluted in hexane 63/80 0C and continuously with a metering pump fed to the polymerization tank.

The concentration of the catalyst was in the polymerization tank 3.33 mg / l suspending agent and that of the cocatalyst 100 mg / l suspending agent. The speed of the stirrer in the polymerization vessel was 150 min-l. The im The pulverulent polymer produced in the reactor was removed from the suspension medium on a centrifuge separated and dried in a partially evacuated container at about 80 OC. Under Under these conditions, a polymer was obtained with the following properties: average Molecular weight 178,000 Melt index MFI 190/5 0.46 g / 10 min according to DIN 53 735 viscosity number I 400 cm3 / g according to DIN 53 728 density at 23 OC 0.956 g / cm3 according to DIN 53 479 molecular Inconsistency 22.2 U (U = Flw / Rn-I) Molecular weight fraction <Rw / S 48.5 total ash 40 ppm The calculated catalyst consumption in this procedure was 45.9 mg Vanadium catalyst / kg polyethylene and 1,380 mg triisobutylaluminum / kg polyethylene. According to DIN 53 468, the polymer powder had a bulk density of 0.509 g / ml. the mean grain size d 'was 595 μm; the powder had in determining the flowability according to DIN draft 53 492 a flow rate V 10 of 9.8 cm3 / sec.

Example 2 In the same apparatus as described in Example 1b, became the catalyst from Example la for the continuous polymerization of ethylene used with the addition of small amounts of butene- (l). The ethylene partial pressure was in the gas space of the polymerization vessel 34.3 bar; the hydrogen partial pressure was there 0.7 bar. Butene- (1) was compared to ethene in a weight ratio of 2 100 offered. Catalyst concentration in the reactor, cocatalyst and cocatalyst concentration in the polymerization reactor, Reactor temperature ,. mean residence time of the catalyst in the polymerization reactor and the speed of the stirrer were opposite Example lb unchanged. A copolymer was produced under these conditions which had the following properties: average molecular weight 168,000 melt index MFI 190/5 0.48 g / 10 min according to DIN 53 735 viscosity number I 380 cm3 / g according to DIN 53 728 density at 23 OC c g / cm3 according to DIN 53 479 molecular non-uniformity U 27.9 (U = RW / F ¢ n-1) Molecular weight fraction <2 5 50.6 total ash 50 ppm ash analysis 14 ppm A1203 10 ppm V205 <10 ppm chlorine The calculated catalyst consumption was 48.6 mg vanadium catalyst / kg polyethylene and 1,430 mg triisobutylaluminum / kg Polyethylene. The bulk density of the polymer according to DIN 53 468 was 0.496 g / ml; the mean powder grain size dt was found to be 540 μm.

When determining the flowability according to DIN draft 53 492 resulted a flow rate VR 10 for the polymer powder of 9.0 cm3 / sec.

Example 3 a) Catalyst preparation 17.33 g (0.10 mol) vanadyl (V) chloride and 11.12 g (0.15 mol) of butanol- (l) were combined in 80 ml of a hexane section 63/80 ° C for 2 hours at room temperature. Subsequently, this mixture and a solution of 25.39 6 (0.20 mol) ethylaluminum dichloride in 112 ml of the hexane cut 63/80 0C synchronously over the course of 2 hours at 25 to 30 0 to 100 ml of the hexane section under nitrogen and while stirring with a paddle stirrer and given a specific stirring power of 300 watt / m3. The suspension obtained was then heated under reflux for a further 2 hours and with the same specific Stirring power stirred. After cooling, the solid was separated off and with a total of Washed 2 l of the hexane cut.

b) Polymerization of ethylene in a 2-1 steel autoclave were under Nitrogen 1 1 of a hexane section 63/80 OC and 0.4 g of triisobutylaluminum submitted. For this purpose, 15 mg of the catalyst prepared according to Example 3a, suspended in a few ml of the hexane cut. After displacing the nitrogen with ethylene 6.3 bar of hydrogen were injected and then ethylene up to a total pressure of 31.4 bar. At the same time the contents of the reactor were heated to 75.degree. The polymerization was stirred for 1 hour at a stirrer speed of 1,000 min-1 at 75 oC, the total pressure being maintained by pushing in ethylene became. Then the reactor was depressurized, after cooling the reactor contents that formed polyethylene filtered off and dried. The yield of polyethylene was 326 g, corresponding to 21.7 kg per g of catalyst. The mean grain size d 'was 560 pm, the bulk density according to DIN 53 468 0.420 g / ml, the flow rate Vn 10 7.4 cm3 / sec (DIN-Entifurf 53 492). The viscosity number according to DIN 53 728 was 180 cm3 / g. The molecular non-uniformity (R / R -1) was determined by gel chromatography determined to be 13, the proportion <w / 5 to 49%.

Example 4 With 10 mg of the catalyst prepared according to Example la ethylene polymerization was carried out as described in Example 3b, but with the addition of 127 mg of ethylaluminum dichloride instead of triisobutylaluminum and pressure of only 1.6 bar Hydrogen. The yield of polyethylene was 232 g, corresponding to 23.2 kg per g of catalyst. The mean grain size d ' was 480 m3, the flow rate VR 10 4.9 cm3 / sec (DIN draft 53 492). The viscosity number according to DIN 53 728 was 520 cm3 / g.

The molecular non-uniformity (W / n-1) was determined by gel chromatography determined to be 5.5, the proportion <w / 5 to 30.8%.

Claims (1)

Process for the production of powdered polyolefins with high Bulk densities (addendum to patent application P 27 00 566.9 and additional patent application P 27 21 377.0) Patent claim process for the production of powdered polyolefins with high bulk densities, good flowability, medium grain diameters up to 1,000 μm and practically no fine grain content due to the polymerization of ethylene, optionally in a mixture with other 4-olefins and in the presence of hydrogen, in inert liquid hydrocarbons at temperatures between 50 OC and about 95 0C and pressures of 10 bar to 100 bar, preferably 20 bar to 60 bar, after discontinuous or continuous process using ZIEGLER catalysts, produced in inert liquid hydrocarbons by converting mixtures of vanadyl (V) chloride and vanadal (V) alcoholate in molar ratios of 1 to 2 to 2 to 1 with ethyl aluminum dichloride and / or diethyl aluminum chloride in molar ratios of aluminum to vanadium compounds from 1 to 1 to 3 to 1 with stirring with specific stirring powers of 0.1 to 20 000 watts / m3, preferably 1 to 5,000 watts3, separation of the insoluble reaction product and activation with organoaluminum compounds according to the main patent ... (Patent application P 27 00 566.9) and according to the additional patent (Patent application P 27 21 377.0), d u r c h e k e n n -z e i c h n e t that instead of a Mixture of vanadyl (V) chloride and vanadyl (V) alcoholate in molar ratios of 1 to 2 to 2 to 1 a reaction product of vanadyl (V) chloride with an alcohol, preferably ethanol, propanol- (l), butanol- (l), in molar ratios of 1 to 2 up to 1 to 1 is used.