NO155142B - PROCEDURE FOR THE PREPARATION OF POWDER FORMED ETHYLENE POLYMERS. - Google Patents

Description

The invention relates to a method for the production of powdered ethylene polymers by polymerization of ethylene or copolymers of ethylene according to the Ziegler method, as the polyolefin powder produced according to the invention is distinguished by the fact that it is particularly suitable for processing into molded parts using the usual machines for plastic processing such as extrusion or injection molding machines.

It is known to polymerize ethylene and 1-olefins with Zigler catalysts from compounds from the transition metals from the fourth to sixth subgroups of the periodic table and organoaluminum compounds to high molecular weight products. It is also known for the production of high-molecular polyolefins by polymerization of ethylene to use mixed catalysts of organoaluminum compounds and compounds from the metals titanium, zirconium, hafnium, vanadium, niobium, tantalum, chromium, molybdenum, tungsten, thorium and uranium, as the heavy metal compounds formed from the catalyst mixture during the reduction are separated from the other reaction products and the separated compounds are used, possibly after further purification, in the desired combination with organoaluminum compounds for the polymerization of ethylene. Furthermore, it is known that catalysts of vanadium compounds such as, for example, vanadium oxytrichloride, vanadium tetrachloride, vanadium trichloride, vanadium chloride and vanadic acid esters and organoaluminum compounds only have a short lifetime and have a low productivity. A further disadvantage of these catalysts is the formation of wall coatings and lumps in the reactor during the polymerization, as well as a completely insufficient quality of the polymer powder for processing into molded parts without prior granulation. The last-mentioned disadvantage can occur as a result of the fact that during the catalyst formation according to the state-of-the-art methods, partially formed

soluble complexes of vanadium and aluminum alkyl compounds.

Polyolefins processed in accordance with the state of the art into molded parts such as hollow cores, tubes, plates or foils are predominantly in the form of granules.

For this purpose, the polyolefins formed in powder form according to the Ziegler process are remelted in twin-screw extruders, plasticized, homogenized with common confectioners and granulated according to known methods. There has been no shortage of attempts to avoid these cumbersome and expensive process steps, however, satisfactory results could not be obtained. The reason for this lies in the fact that, compared to granules, the powdered polyolefins mostly have significantly lower volume weights, significantly higher specific surface areas of the powder grains and often also dust amounts. Certain undesirable properties of the powders cause the known disadvantages of their processing. As a result of the low volume weights and the moderate to poor flowability of the powders, a reduction in production occurs during extrusion, compared to granules,

which can be up to 50% and more. The strongly cleft surface of the powder grains causes air bubbles to be trapped in the melt during melting. This leads to incorrect and or even unusable finished parts.

A vesicular melt can occur when wetting the powders because of their high specific surface area can occupy significantly more than granulates. The dust in the powders causes difficulties during pneumatic transport. Thus, for example, it may be necessary instead of

Be sure to use an inert gas such as nitrogen to exclude the danger of dust explosions due to electrostatic charging.

In contrast, it has now surprisingly been found that

it is possible to produce powdered ethylene polymers which have valuable technical properties using catalysts of vanadium compounds and organoaluminum compounds which have a high productivity and a long lifetime.'

The invention relates to a method

for the production of powdered ethylene polymers or copolymers of ethylene with small amounts of propene or butene-1, with a high bulk density, good flowability, medium grain diameter

up to 1000 µm and practically without fine particles by polymerization in the presence of hydrogen in inert liquid hydrocarbons at temperatures between 50°C and 95°C and pressures from 10-100 bar, preferably 20-60 bar, by discontinuous or continuous process using Ziegler catalyst prepared in inert liquid hydrocarbons by reaction of chlorine- and alkoxy-containing vanadyl(V) compounds with organoaluminum compounds, separation of insoluble reaction products and activation by arbitrary

organoaluminum compounds, characterized in that 1: as vanadyl(V) compound, a reaction product of vanadyl(V) chloride and a vanadyl(V) alcoholate with 2-4 carbon atom-containing alkyl groups is used in a molar ratio of 1:2 to 2:1 or direct reaction products of vanadyl(V) chloride with an alcohol with 2-4 carbon atoms, , preferably ethanol, propanol-(1), butanol-(1), in molar ratios from 1:2 to 1:1, and

2: as organic aluminum compounds for reduction, ethylaluminum chloride and/or diethylaluminum chloride or isobutylaluminum chloride and/or diisobutylaluminum chloride are used in a molar ratio between aluminum and vanadium compound of 1:1 to 3:1, 3: the reaction of the vanadium compounds with the organoaluminum compounds is carried out while stirring with specific stirring performance from 1-20,000 watts/m<3>, and 4: the activation takes place with aluminum alkyl compounds of the formula A1R3, in which R means alkyl groups with 2-8 C atoms or with alkyl aluminum sesquichloride and/or alkyl aluminum dichloride, especially ethyl aluminum sesquichloride and/or ethyl aluminum dichloride.

Vanadyl(V) alcoholates include those with a straight line as well as those with branched alkyl residues. Alcoholates with 2-4 C atoms per alkyl residue. The reaction of vanadyl(V) chloride with vanadyl(V) alcoholate is usually carried out in an inert liquid hydrocarbon at room temperature or at too high a temperature. In the same way, it is also possible instead of the reaction product of vanadyl(V)-chloride and vanadyl(V)-alcoholate directly to use the reaction product of vanadyl(V)-chloride with an alcohol, preferably ethanol, propanol-(1) or butanol -(1), in a molar ratio between vanadyl(V) chloride and alcohol of 1:2 to 1:1, preferably 1:1.5, with a hydrocarbon.

When producing the catalyst according to the invention, both the molar ratio of vanadyl (V) chloride to vanadyl (V) alcoholate and the molar ratio of aluminum to vanadium compound are critical. By observing the molar ratios according to the invention, the formation of soluble aluminum vanadium complexes is avoided and, surprisingly, a catalyst is produced with such a compact grain that enables the production according to the invention of powdered ethylene polymers with outstanding properties. It is desirable to set a coarse powder grain at the same time as high volume weight of the powder. The average grain size of the polymer powder is dependent on the average particle size of the catalyst grain. The latter can be controlled by the method according to the invention by the stirring performance during the reaction of the vanadium compound with the organoaluminum compound. Higher specific stirring performance leads to a finer catalyst grain and thus, under the same polymerization conditions, to a smaller mean grain diameter of the polymer.

It was completely surprising and not predictable in any way that application of the method according to the invention in the catalyst production would enable such a technical advance that could be realized with regard to the production of powdered ethylene polymers. The use of the new catalysts in the method according to the invention takes place in a manner known per se under the conditions usual for low-pressure polymerizations according to Ziegler, as they have already been indicated above. Because of the productivity of the catalyst according to the invention, it is not necessary to take precautions for removing the catalysts from the polysericate.

When using the direct reaction product of vanadyl(V)-chloride and alcohol, one also has the special advantage that the laborious preparation of chlorine-free vanadyl(V)-alcoholates can be disregarded and instead a reaction product of vanadyl(V)- alcoholate with vanadyl(V) chloride, an easily obtainable chlorine-containing reaction mixture of vanadyl(V) chloride with an alcohol. The reaction of vanadyl(V) chloride with alcohol is conveniently carried out in an inert liquid hydrocarbon at room temperature or at high temperature, depending on the reaction conditions, more or less hydrogen chloride escapes. Thus, for example, by using a liquid inert hydrocarbon in the cooking area, from approx. 60 - 80°C by several hours of heating under reflux, the reaction of vanadyl(V)-chloride with the alcohol liberated approximately quantitative hydrogen chloride. For the method according to the invention, however, a portion of hydrogen chloride remaining in the reaction mixture is not of significant importance. As alcohol, we are talking about generally saturated monohydric alcohols with linear or branched alkyl residues. The best results with regard to the highest possible catalyst activity are achieved with primary monovalent linear alcohols. With respect to the high volume density, freedom from dust and good flowability of the polymer powders, particularly good results are obtained by using ethanol, propanol-(l) and butanol-(l). If the C number of the alcohols is greater than four, with increasing chain lengths, increasingly finer powders are obtained, which are less desirable for processing into plastic finished parts.

The insoluble vanadium-containing catalyst component produced according to the invention can be activated with halogen-free as well as halogen-containing organic aluminum compounds. In all cases, the polymerisation of ethylene under the conditions stated above yields polymer powder of excellent quality with regard to flowability, volume weight and freedom from dust. When using halogen-free organic aluminum compounds such as free alkyl aluminum to activate the vanadium-containing catalyst components according to the invention, polymers with a wide molecular weight distribution are obtained

ing which is particularly suitable for processing after extrusion

tion process for foil, sheets, hollow bodies, tubes and profiles. By using halogen-containing organoaluminum compounds such as ethylaluminum sesquichloride and/or ethylaluminum dichloride, on the other hand, polymers with a narrow molecular weight distribution are obtained, which is particularly advantageous for the production of injection molded particles.

As is known, injection molded particles of low-pressure polyethylene with a narrow molecular weight distribution of the polymers compared to such polymers with a broad molecular weight distribution have a number of advantages, such as, for example, a small tendency to stretch, high stackability and good usability even at very low temperatures.

For activation, ethylaluminum dichloride and/or diethylaluminum chloride as well as isobutylaluminum dichloride and/or diisobutylaluminum chloride can be used.

Isobutylaluminum chloride excels in relation to corresponding ethylaluminum compounds in the technical implementation of the method according to the invention in that it has a lower melting or solidification point and a better solubility in liquid carbons at low temperatures. Isobutylaluminum chloride has a melting point of -30°C, while ethylaluminum chloride already solidifies at 32°C (Ullmann's Encyklopadie der technischen Chemie, 4th edition, volume 7, page 344, publisher Chemie GmbH, 1973). In contrast to ethyl aluminum dichloride, it is not necessary to heat the storage container and pipelines.

The powdered polyethylenes produced by the method according to the invention resp. copolymers of ethylene and propylene and/or butylene-(l) are suitable depending on their molecular weight setting and composition of the catalyst used for their production according to the invention for use in the injection molding or extrusion sector.

The powders produced according to the invention of high volume density from approx. 0.420 to 0.550 g/ml (DIN 53 468) is practically free of dusty fine particles. It has excellent rippling ability. The trickle rate according to the draft DIN

53 492 when using an outlet opening with a diameter of 10 mm amounts to 6 to 10 cm<3>/sec. With the according to inven-

iron-produced powders, by processing them as plastics, it is possible to achieve the greater production resp. ejection performance, the larger the average grain diameter is, as the following table shows. The average grain size d' is determined from the RRSB distribution function (DIN 66 145). According to this, d' is defined so that 36.8% by weight of the powder has a larger grain diameter than d'.

Of course, the numerical values given in the table are for production or ejection performance comparison figures which are determined under similar circumstances and whose absolute value and possibly also ratio is strongly dependent on the processing machines. \,

Depending on the molecular weight distribution, the poly-olefin powders produced according to the invention can be easily processed into molded parts such as injection molding articles or extrusion articles such as e.g. pipes, plates, profiles, hollow bodies and foils. Due to the compact grain structure, the melt is practically free of blisters. Preferably, of the powders according to the invention, the coarser ones are used because in their overall proportions during the plastic processing they are most similar to the granules.

The method according to the invention shall, for example, be explained with the help of the following examples:

Example 1

a) Catalyst production

122.3 g (705.7 mmol) vanadyl(V) chloride and

172.3 g (705.7 mmol) of vanadyl(V)-n-propylate are heated together in 1.7 1 of a 63/80°C hexane mixture under nitrogen for 2 hours at 55°C. After the mixture had cooled, a solution of 340.3 g (2822.6 mmol) of diethylaluminum chloride in 1.43 1 of the 63/80°C hexane mixture was added at 20 to 25°C over 2 hours while stirring with a blade stirrer and a specific stirring performance of 126 watts per m<3>. The resulting suspension is then stirred for 2 hours at 55°C with the same specific stirring performance. After cooling, the solid was separated and washed five times with each time 5 L of the hexane mixture.

b) Polymerization of ethylene

In a 2 1 steel autoclave it was under

nitrogen filled with 1 liter of the hexane mixture 63/80°C and 0.4 g of triisobutylaluminium. In addition, 30 mg of the catalyst prepared according to example la has been suspended in a few milliliters of the hexane mixture. After displacing the nitrogen with ethylene, 6.3 bar hydrogen and then ethylene were pressurized until a total pressure of

31.4 bar. At the same time, the reactor contents were heated to 75°C. The polymerization was carried out for 1 hour with stirring at a stirring speed of 1000 min. at 75°C, the overall pressure being maintained by post-pressurization of ethylene. The reactor was then decompressed after cooling the reactor contents, the polyethylene formed was filtered off and dried. The yield of polyethylene was 356 g, corresponding to 11.9 kg per g catalyst. The grain size d' amounted to 610 µm, volume density after

DIN 53 468 0.460 g/ml, the trickle time according to DIN draft

53,492 at an outlet opening with a diameter of 10 mm 16.6 sec., corresponding to a trickle velocity V.n of

R X U

9.41 cm<3>/sec.

Example 2.

a) Catalyst production.

It was proceeded as in example la, however,

instead of the diethylaluminum chloride solution, a solution of 535.7g (4.220 mol) ethylaluminum dichloride in 2.27 1 of the hexane mixture 63/80°C was used for reaction with a mixture of 182.8g (1.055 mol) vanadyl(V) chloride and 257, 6 g (1.055 mol) vanadyl(V)-n-propylate in 1.77 1 of the hexane mixture.

b) Polymerization of ethylene.

The procedure was as in example 1b, however, without the use of 20 mg of the catalyst prepared according to point 2a instead of the catalyst prepared according to point la. The yield of polyethylene was 221 g, corresponding to 11.1 kg per g catalyst. The grain size d' amounted to 480 um, the volume density according to Din 53 468 0.430 g per ml, the trickle time according to DIN draft 53 492 at an outlet opening with a diameter of 10 mm 19.4 sec., corresponding to a trickle speed V . on

o K -LU

8.05 cm/sec..

Comparison example 1:

a) Catalyst production

In the manner mentioned in the example, one was traded

mixture of 274.3 g (1.583 mol) vanadyl(V) chloride and 128.9 g (0.528 mol) vanadyl(V)-n-propylate (molar ratio chloride/alkoxide = 3 : 1) in 1.84 1 of the hexane mixture 63/80°C with 535.7 g (4.220 mol) ethyl aluminum dichloride in 2.25 1 from the hexane mixture.

b) Polymerization of ethylene.

With 15 mg of this catalyst, it was carried out

an ethylene polymerization as discussed in example lb. The yield of polyethylene was 173 g, corresponding to 11.5 kg per g catalyst. The grain size d' amounted to only l4o jam, the volumetric weight according to your 53 468 only 0.200 g/ml, the trickle time according to your draft 53 492 at an outlet opening with a diameter of 10 mm .106.6 sec., corresponding to a trickle velocity V of 1.47 cm / sec..

Comparison example 2:

a) Catalyst production.

8.67 g (50 mmol) of vanadyl(V) chloride and 12.21 g

(50 mmol) vanadyl(V)-n-propylate was heated together in 85 ml of a hexane mixture at 63/80°C under nitrogen for 2 hours under reflux. After the mixture had cooled, a solution of 76.17 g (600 mmol) ethylaluminum dichloride (mol forhol Al-(V compounds = 6:1)) in 35 ml of the hexane mixture 63/80°C was added at 25°C over 2 hours under stirring, with a specific stirring power of 400 watts per m 2. The resulting suspension was then heated for 2 hours under reflux and thereby stirred with the same specific stirring power, primarily dissolving the formed precipitate.

b) Polymerization of ethylene.

With 5 ml of this catalyst solution (containing 1 mmol V compound) and 2 g of triisobutylaluminum, a ethylene polymerization as discussed in example lb. The yield of polyethylene amounted to g. Very rapid growth of the polynierisate occurred on the autoclave wall and on the stirrer. The polymer had a grain structure and were clumped together. Volume density according to di-n 5'3 468 amounted to only 0.110 g per ml.

Example 3.

a) Catalyst production.

8.67 g (50 mmol) vanadyl(v) chloride and 14.32 g (50

mMol) vanadyl(V)-isobutylate was heated together in 85 ml of a hexane mixture 63/80°C under nitrogen for 2 hours under reflux. After the mixture had cooled, a solution of 25.4 g (200 mmol) of ethylaluminum dichloride in 118 ml of the 63/80°C hexane mixture was added at 25°C over the course of 2 hours while stirring with a blade stirrer and a specific stirrer output of 400 watts/ m. The resulting suspension was then heated for another 2 hours under reflux and thereby stirred with the same specific stirrer performance. After cooling, the solid was separated and washed 5 times with each time 500 ml of the hexane mixture.

b) Polymerization of ethylene.

With 10 mg of this catalyst, it was carried out

an ethylene polymerization as discussed in example 1b, however with a hydrogen partial pressure of 1.6 bar. The yield of polyethylene

amounted to 184 g, corresponding to 18.4 kg per g catalyst. The grain size d<1> was 460 µm, bulk density according to your 53,468 °>475 g/ml, trickle time according to your draft 53,492 with an outlet opening with a diameter of 10 mm 19.8 sec. corresponding to a rice "le velocity VD I, L_ ) of 7.89 cm r>/sec..

Example 4.

In a 750 1 stirred tank reactor, the vanadium catalyst mentioned in example la was used in continuous polymerization with ethylene. The polymerization took place in suspension as a suspension medium, a hexane mixture was used in the boiling range between 63°C and 80°C. The filling level in the polymerization reactor was 300 1, and 4 hours was chosen as the average residence time of the catalyst in the reactor. Maintenance of the stand took place over a Co-60 beam cabinet connected to a double ball crane line.

The polymerization was carried out at a temperature

at 75°C. Ethylene partial pressure in the reactor's gas chamber amounted to 31.8 bar. Hydrogen was used for molecular weight regulation, the hydrogen partial pressure in the reactor's gas space was 3.2 bar. Triisobutylaluminum was used as cocatalyst. Catalyst and co-catalyst were diluted in an agitator container in hexane 63/80°C and supplied with a membrane pump continuously to the reactor. The concentration of the catalyst in the polymerization container was 9.33 ml/l, suspending agent and the Co-catalyst 100 mg/l suspending agent. The speed of the agitator in the polymerization reactor was set at 150 min. The powdered polymer formed in the reactor was separated on

a centrifuge from the suspension agent and dried in a partially evacuated container at approx. 80°C. Under these test conditions, a polymer was formed with the catalyst mentioned in example la, which has the following properties:

The numerically calculated catalyst consumption amounted to 57.5 mg vanadium catalyst/kg polyethylene and 620 mg triisobutylaluminium/kg polyethylene. According to DIN 53 468, the polymer powder produced in this way had an unusually high bulk density of 0.550 g/ml. The average grain size d' amounted to 750 µm. When determining the trickling ability according to DIN draft 53 492, the powder had an expiration time V t0 in 10 of only 15o .6 sec. This corresponds to a trickling speed V ti 10 of 10.02 cm / sec..

Example 5.

The catalyst mentioned in example 1 a was used in the same apparatus for the continuous polymerization of ethylene in a mixture with propylene. The addition of 10 wt-$ propylene, referred to that per The amount of ethylene offered per hour caused, compared to homopolymerization, a clear lowering of the average molecular weight. Thereby, the desired average molecular weight could be set with a hydrogen partial pressure of only 1.2 bar in the reactor's gas space. The ethylene partial pressure was 33)8 bar. The average residence time of the catalyst in the reactor was 2 hours. The catalyst concentration was set at 27 mg vanadium catalyst/l suspending agent and 100 mg triisobutylaluminium/l. With this method, a polymer with the following properties was formed:

The numerically calculated catalyst consumption was 29.8 mg vanadium catalyst/kg polyethylene and 530 mg triisobutylaluminium per kg polyethylene. The bulk density according to DIN 53^68 of the polymer powder was 0.501 g/ml. The average grain size d' amounted to 570 µm. When determining the flowability, the powder had an expiration time t_ K lu of „ 22.2 sec. corresponding to a trickle velocity V,.. n of 7»04 cm0/sec..

Example 6.

With the catalyst mentioned in example 2a, ethylene was continuously polymerized in the apparatus already mentioned. The hydrogen partial pressure in the reactor's gas chamber was set at 2.5 bar, the ethylene partial pressure was 32.5 bar. The catalyst concentration in the polymerization reactor amounted to k mg vanadium catalyst/l suspending agent and 100 mg triisobutylaluminium/l suspending agent. As an average length of stay'

of the catalyst in the reactor, 2 hours was chosen. This resulted in polyethylene with the following data:

Melting index MFI 190/5

The numerically calculated catalyst consumption amounted to 50.7 mg vanadium catalyst/kg polyethylene and 1,230 mg triisobutylaluminium/kg polyethylene. The volume density of the polymer powder was 0.485 g/ml. The average grain size d<1> was at 660 µm, the polymerized powder had an expiration time t„ of 18.2 sec when determining the trickling ability, corresponding to a trickling speed yR of 8.59 cmr/sec.

Example 7.

In the semi-technical polymerization apparatus from example k, the catalyst from example 2a was used for the polymerization of ethylene in a mixture with pjjopylene. Ethylene partial pressure in the reactor's gas space was 34.1 bar, hydrogen partial pressure was 0.9 bar, propylene was offered in comparison to ethylene in a weight ratio from 6 to 100. The catalyst concentration was 3.3 mg vanadium catalyst/l suspension agent. The average residence time of the catalyst in the reactor was 2 hours. Under these test conditions, polyethylene emerged with the following properties:

Melting index MFI 190/5

The numerically determined consumption of catalyst amounted in this example to 37.4 mg vanadium catalyst/kg polyethylene and 1,120 mg triisobutylaluminium/kg polyethylene. The polymer powder had a volume density of 0.475 g/ml, the average grain size was 640 µm. When determining the flowability according to DIN draft 53 492, an expiration time t_ was measured. in 18.9 sec. It corresponds to a trickle rate

R lu „

VR 1() of 8.27 cm-ysec.

Example 8.

In the same way as described in example 7, ethylene was polymerized in a mixture with 6 wt.-/butene-1. The polymerizate thus formed had the following data:

Melting index MFI 190/5

The numerically determined catalyst consumption was 33.8 mg vanadium catalyst/kg polyethylene and 1,020 mg triisobutylaluminium/kg polyethylene. The powder had a volume density of 0.482 g/ml, the average grain size was 660 ura. The discharge time t_ n_ of the powder when determining the trickling ability amounted to 18.2 sec., corresponding to a trickling speed V -. of 8.59 cm<J>/sec.

Example 9»

a) Catalyst production.

The procedure was as described in example 2a, however, it was stirred with a specific stirring power of 3,400 watts/

3

m.

b) Copolymerization of ethylene and butene-1.

The catalyst mentioned in example 9a was used

in the semi-technical apparatus for continuous polymerization of ethylene in mixture with 3 wt-^ butene-1. Reactor temperature, average residence time in the reactor, as well as hydrogen and ethylene partial pressure were as high as stated in example 7. The concentration of vanadium catalyst in the reaction vessel was 4 mg/l, concentration of triisobutylaluminum was as high as in example 7. The polymer thus produced had the following properties :

Melting index MFI 190/5

The numerically determined catalyst consumption was 49.5 mg vanadium catalyst/kg polyethylene and 1,230 mg triisobutylaluminium/kg polyethylene. The polymer powder had a volume density of 0.492 g/ml, the average grain size was 430 µm. When determining the trickling capacity, an expiration time t K 10 of 24.7 seconds was measured. This corresponds to a trickling speed V . of 6.33 cm/sec.

Example 10.

a) Catalyst production.

The procedure was as described in example 2a, however, it was stirred with a specific stirring power of o 5 watts/m 3.

b) Copolymerization of ethylene and butene-1.

With the vanadium catalyst mentioned in example 10a

ethylene was continuously polymerized in mixture with 3 wt-$ butene-1. The hydrogen partial pressure was 0.7 bar, the ethylene partial pressure in the reactor's gas space was 34.3 bar. The vanadium catalyst was offered in a concentration of 2.7 mg/l of the suspension mixture. The concentration of the cocatalyst triisobutylaluminum was as high as stated in example 7. The polymer thus produced had the following properties:

Melting index MFI 190/5

The numerically calculated catalyst consumption was 28.7 mg vanadium catalyst/kg polyethylene and 1,080 mg triisobutylaluminium/kg polyethylene. The polymer powder had a volume density of 0.423 g/ml, the average grain size d' was 960 µm. When determining the flowability according to DIN draft 53 492, the expiration time t_, .,__ was 24.7

K 10 „ sec., that corresponds to a trickle velocity V0 K 10 of 6.33 cm/sec.

Example 11.

a) Preparation of the vanadium-containing catalyst components.

182.8 g (1.055 mol) vanadyl(V) chloride and 257.6 g (1.055 mol) vanadyl(V)-n-propylate were heated together in 1.77 L of a hexane mixture 63/80°C under nitrogen for 2 hours at 55°C. After cooling the mixture, a solution of 535.7 g (4.220 mol) ethylaluminum dichloride in 2.27 L of the hexane mixture was added at 20 to 25°C to 63/80°C over 2 hours while stirring with a blade stirrer with specific stirrer -performance of 126 watts/m . The resulting suspension was then stirred for another 2 hours at 55°C with the same specific stirring power. After cooling, the solid was separated and washed 5 times with each time 5 1 of the hexane mixture.

b) Polymerization of ethylene.

In a 2 L steel autoclave under nitrogen, 1 L was av

the hexane mixture 63/80°C, 254 mg (2 mmol) ethyl aluminum dichloride and 15 mg of the catalyst component prepared according to example 1a suspended in a few ml of hexane mixture. This mixture was stirred for 30 min. at room temperature. Then, after displacement of nitrogen with ethylene, 1.6 bar of hydrogen and then ethylene were applied to a total pressure of 31.4 bar. At the same time, the reactor contents were heated to 75°C. The polymerization was carried out for 1 hour with stirring

with a stirring speed of 1000 min.<->"'" at 75°C, while the overall pressure was maintained \ed repressurization of ethylene. The reactor was then decompressed, after the reactor's contents had cooled, the polyethylene formed was filtered off and dried. The yield of polyethylene was 292 g, corresponding to 19.5 kg per g catalyst.

The average grain size d' was 590 µm, volume density according to DIN 53 468 0.445 g/ml, the stirring speed V0 1 n 8.68 cm3/sec. (DIN draft 53 492). Viscosity number according to DIN 53 728 amounted to 400 cm 3 /g. The molecular heterogeneity (M - /M - n-1) was determined gel chromatographically to be 4.6. The amount <M^/5 to 25.4

Example 12.

a) Preparation of the vanadium-containing catalyst components.

182.8 g (1.055 mol) vanadyl(v) chloride and 257.6 g (1.055 mol) vanadyl(V)-n-propylate were stirred together for 1.66 1

of a hexane mixture 63/80°C for 1 hour at room temperature. This mixture and a solution of 535.7 g (4.22 mol) ethyl aluminum dichloride in 230 L of the 63/80°C hexane mixture were added synchronously over 2 hours at 25°C to 2 L of the hexane mixture while stirring with a blade stirrer and a specific rudder performance of 1000 watts/m . The resulting suspension was then uniformly heated for 2 hours under reflux and thereby stirred with the same specific stirring performance. After cooling, the solid was separated and washed 5 times with each time 5 1 of the hexane mixture.

b) Polymerization of ethylene.

The vanadium-containing catalyst component mentioned under example 12a was used with ethylaluminum sesquichloride in a 750 liter stirred tank reactor for the continuous polymerization of ethylene. The polymerization took place in suspension, as a suspension medium a hexane mixture was used in the boiling range between 63°C and 80°C. The filling level in the polymerization reactor was 300 1, the average residence time of the catalyst in the reactor was 2 hours. Filling level maintenance in the polymerisation ion reactor took place over a Co-60 beam counter. connected by a double ball valve extension.

The polymerization was carried out at a temperature of 75°C. Ethylene partial pressure in the gas space in the polymerization reactor amounted to 30.6 bar. For molecular weight regulation of the polymer, hydrogen was used, hydrogen partial pressure in the gas space in the reactor was 4.4 bar. The vanadium-containing catalyst component and ethylaluminum equichloride were diluted in a stirred tank in hexane 63/80°C and fed after an average residence time of 0.5 hours with a membrane pump continuously to the reactor. The concentration of the vanadium-containing catalyst component in the polymerization vessel was 7.33 ml/l suspending agent and the concentration of ethyl aluminum sesquichloride 100 ml/l suspending agent. The speed of the stirrer in the polymerization reactor was set at

150 min. • The powdered polymer formed in the reactor was separated on a centrifuge from the suspension agent and dried in a partially evacuated container at approx. 80°C. Under these experimental conditions, a polymer was formed which has the following properties:

Melting index MFI 190/5

The consumption of vanadium-containing catalyst component by this method amounted to 72.2 mg/kg polyethylene and of ethyl aluminum sesquichloride 985 mg/kg polyethylene. The polymer powder thus produced had a volume density of 0.435 g/ml determined according to DIN 53 468. The average grain size d' amounted to 300 pm. The powder had a trickle velocity Vt> -i f* - 7.2 cm3/sec, determined according to DIN draft 53 492.

ix 1U

Example 13»

a) The preparation of the vanadium-containing catalyst component.

The procedure was as in example 12a, however, it was stirred with a specific stirring power of 126 watts/m .

b) Polymerization of ethylene.

In the polymerization apparatus mentioned in example 12b, a vanadium-containing catalyst component prepared according to example 13a was used with ethyl aluminum sesquichloride for the continuous polymerization of ethylene.

In the gas space of the polymerization reactor, an ethylene partial pressure of 31 bar was set, the hydrogen partial pressure there was 4 bar. The concentration of the vanadium-containing catalyst component in the polymerization reactor amounted to 6.7 mg/l suspending agent, the concentration of ethyl aluminum sesquichloride was unchanged in relation to example 12b. With this method, a polymer with the following properties was formed:

Melting index MFI 190/5

Under the mentioned experimental conditions, the consumption of vanadium-containing catalyst component amounted to 68.7 mg/kg polyethylene and of ethylaluminum sesquichloride in: 030 mg/kg polyethylene.

The polymer powder had a volume density according to

DIN 53 468 of 0.; 425 g/ml. The average grain size 8' was 560 µm, the polymerized powder had a creep velocity V„ K -LU= 8.4 cm/sec when determining the "ripple ability" according to DIN draft 53-492.

Example 14.

a) Preparation of the vanadium-containing catalyst component.

The procedure was as in Example 1a, however, instead of ethylaluminum dichloride solution, a solution of 340.3 g (2,822.6 mmol) of diethylaluminum chloride in 1.43 1 of the hexane mixture 63/80°C was brought into reaction with a mixture of 122.3 g (705.7 mmol) vanadyl(v) chloride and 172.3 g (705.7 mmol) vanadyl(V)-n-propylate in 1.7 1 of the hexane mixture 63/80°C.

b) Polymerization of ethylene.

The vanadium-containing catalyst component mentioned under example 14a in the apparatus mentioned in example 12b used for continuous polymerization of ethylene. At a filling level in the polymerization reactor of 300 1, an average residence time of the catalyst in the reactor of 4 hours was chosen. As discussed in example 12b, the vanadium-containing catalyst component was diluted in a stirring vessel in hexane 63/80°C before it was introduced into the polymerization vessel, the concentration in the polymerization reactor was 16 mg/l suspension agent. Ethyl aluminum sesquichloride was pumped from a storage tank directly into the polymerization reactor where a concentration of 100 mg/l suspending agent was maintained.

The ethylene partial pressure in the reactor's gas chamber amounted to 32.7 bar. For molecular weight regulation, hydrogen was pressurized to a partial pressure of 2.3 bar in the reactor's gas space. The method described here produced a polymer with the following properties:

Melting index MFI 190/5

The consumption of vanadium-containing catalyst components amounted to 97.4 mg/kg polyethylene and of ethyl aluminum sesquichloride 620 mg/kg polyethylene. The volume density of the polymer was 0.440 g/ml. The powder had an average grain size d' =

790 pm, and when determining the rippling ability a rippling velocity VR1Q of 8.2 cm<3>/sec..-Example 15»

With 10 mg of the catalyst component prepared according to example 1a, an ethylene polymerization was carried out; tion as described in example 11b, however, with the addition of 310 mg (2 mmol) of isobutylaluminum dichloride instead of ethylaluminum dichloride and with the omission of the pre-reaction of 30 min. between the vanadium-containing catalyst component and the organoaluminum compound. The yield of polyethylene was 164 g, corresponding to 16.4 kg per g catalyst. The molecular heterogeneity was determined by gel chromatography to be 4.6, the amount of sr Mw/5 to 26.7%.

Example 16.

a) Catalyst production.

346.6 g (2 mol) vanadyl(V) chloride and 180.3 g (3 mol)

propanol-(1) was heated together in a 1.59 L of a hexane mixture at 63/80°C for 2 hours under reflux while avoiding hydrogen chloride. Then this mixture and a solution of 507^8 g (4 mol) ethyl aluminum dichloride in 2.25 1 of hexane mixture

iling 63/80°C added synchronously over 2 hours to 2 1 of the hexane mixture at 28°C under nitrogen while stirring with a blade stirrer and a specific stirrer power of 95 watts/m . The resulting suspension was then additionally heated for 1 hour under reflux and thereby stirred with the same specific stirrer performance. After cooling, the solid was separated and washed 3 times with each time 5 1 of the hexane mixture.

b) Polymerization of ethylene.

The vanadium catalyst mentioned in example 16 was

used in a 750 1 agitator container for continuous polymerization of ethylene. The polymerization of ethylene took place in a suspension of a hexane mixture in the boiling range between 63°C and 80°C and powdered polyethylene and catalyst. The filling level in the polymerization vessel was set to 300 1, and 2 hours was chosen as the average residence time of the catalyst in the polymerization vessel.

The polymerization was carried out at a temperature of 75°C. The ethylene partial pressure in the gas space of the polymerization beliolder amounted to 3^.1 bar. For regulation of the average molecular weight, hydrogen was used, the hydrogen partial pressure in the gas space of the polymerization reactor was 0.9 bar. Triisobutylaluminum was used as Co-catalyst for activation. Catalyst and Gocatalyst were diluted in a stirrer container in hexane 63/80°C and added to a dosing pump

continuously to the polymerization vessel.

The concentration of the catalyst in the polymerization vessel was 3.33 mg/l suspending agent and the concentration of the Co-catalyst 100 mg/l suspending agent. The mixer's turning number in the polymerisation container was 150 min<->"<*>". The powdered polymer formed in the reactor was separated on a centrifuge from the suspending agent and dried in a delev-kitten container at approx. 80°C. Under these conditions, a polymerization with the following characteristics was formed: molecular non-uniformity

The numerically calculated catalyst consumption by this method amounted to 45.9 mg vanadium catalyst/kg polyethylene and 1,380 mg triisobutylaluminium/kg polyethylene. According to DIN 53 468, the polymer powder had a volume weight of 0.509 g/ml. The average grain size d' marked was 595 µm, the powder had a trickling speed Vn when determining the trickling ability according to DIN draft 53 492. n of 9.8 cm^/sec.

Example 17.

In the same apparatus as described in example 16b, the catalyst from example 16a was used for the continuous polymerization of ethylene with the addition of smaller amounts of butene-(1). The ethylene partial pressure in the gas space of the polymerization vessel was 34.3 bar, the hydrogen partial pressure there was 0.7 bar. Butene-(l) was compared to ethylene offered in weight ratios from 2 to 100. The catalyst concentration in the reactor, the Co catalyst as well as the Co catalyst concentration in the polymerization reactor, reactor temperature, mean residence time of the catalyst in the polymerization reactor and the agitator speed were unchanged compared to example l6b. Under these conditions, a copolymer was produced which has the following properties:

The numerically calculated catalyst consumption amounted to 48.6 mg vanadium catalyst/kg polyethylene and 1,430 mg triisobutylaluminium/kg polyethylene. The volume density of the polymer according to DIN 53 468 was 0.496 g/ml, the average powder grain size d' was found to be 540 µm. When determining the creepability according to DIN draft 53 492, a creep velocity VR j.Q for the polymer powder was found to be 9.0 cm/sec.

Example 18.

a) Catalyst production.

17.33 g (0.10 mol) vanadyl(v) chloride and 11.12 g

(0.15 mol) of butanol-(1) was stirred together in 80 ml of one hexane mixture 63/80°C for 2 hours at room temperature. Then this mixture and a solution of 25.39 g (0.20 mol) of ethylaluminum dichloride in 112 ml of the 63/80°C hexane mixture were added synchronously over 2 hours at 25-30°C to 100 ml of the hexane mixture under nitrogen and while stirring with a blade stirrer and a specific stirring power of 300 watts/m . The resulting suspension was then further heated for 2 hours under reflux and then stirred with the same specific stirring power. After cooling, the solid was separated and washed with a total of 2 l of the hexane mixture.

b) Polymerization of ethylene.

In a 2 liter steel autoclave, it was taken below

nitrogen 1 1 of a hexane mixture 63/80°C and 0.4 g of triisobutylaluminium. To this was added 15 mg of the catalyst prepared in example 18a, suspended in a few ml of the hexane mixture. After displacing the nitrogen with ethylene, 6.3 bar hydrogen and then ethylene were pressurized with up to a total pressure of 31.4 bar. At the same time, the reactor contents were heated to 75°C. The polymerization was carried out for 1 hour with stirring at a stirring speed of 1000 min""'' at 75°C, while the total pressure after the application of ethylene was maintained. The reactor was then decompressed after cooling the reactor contents, the polyethylene formed was filtered off and dried. The yield of polyethylene was 326 g, corresponding to 21.7 kg/g of catalyst. The average grain size d' was 560 µm, the volume density according to DIN 53 468 0.420 g/ml, trickle velocity <V>R 1() 7.4 cm<3>/sec. (DIN draft 53 492). Viscosity number according to DIN 53 728 amounted to 180 cm<3>/g. The molecular non-uniformity (M /Si -l) was tuned gel chromatograph in sk to 13, the amount <M /5

w n /w

to 49#.

Example 19.

With 10 mg of the catalyst prepared according to example 16a, an ethylene polymerization was carried out as described in example 18b, however with the addition of 127 mg of ethylene aluminum dichloride instead of triisobutylaluminum and applying a pressure of only 1.6 bar in hydrogen. The yield of polyethylene was 232 g, corresponding to 23.2 kg per g catalyst. The average grain size d' was 480 µm, the trickle velocity V0 4.9 cm<3>/sec. (DIn draft 53 492). We shoe site numbers

K 10 q

according to DIN 53 728 amounted to 520 cm<J>/g. The molecular heterogeneity (M 2 /m 2 -1) was determined gel chromatographically to be 5.5, the quantity xM /5 to 30.8 4>.

w

Example 20.

a) Catalyst production.

9.14 g (52.7 mmol) vanadyl(V) chloride and 12.88 g •

(52.7 mmol) vanadyl(V)-n-propylate was heated together in 89 ml of a hexane mixture 63/80°C under nitrogen for 2 hours under reflux. After the mixture had cooled, a solution of 32.7 g (211 mmol) of isobutyl aluminum dichloride in 114 ml of the hexane mixture 63/80°C was added at 25°C over the course of 2 hours while stirring with a blade stirrer and a specific stirrer output of 400 watts/m . The resulting suspension was then heated for another 2 hours under reflux and thereby stirred with the same specific stirrer performance. After cooling, the solid was separated and washed 5 times with each time 500 ml of the hexane mixture.

b) Polymerization of ethylene.

In a 2 liter steel autoclave it was under nitrogen

filled in 1 liter of a hexane mixture 63/80°C and 0.4 g of triisobutylaluminium. To this was added 10 mg of the catalyst prepared according to example 20a, suspended in a few milliliters of the hexane mixture. After displacement of nitrogen with ethylene, ±, <6 bar hydrogen and then ethylene were applied up to a total pressure of 31.4 bar. At the same time, the reactor contents were heated to 75°C. The polymerization was carried out for 1 hour. while stirring with a stirrer speed of 1000 min. ^ at 75°C as the overall pressure was maintained after applying ethylene. Then the reactor was decompressed, after cooling the reactor contents formed polyethylene was filtered off

and dried. The yield of polyethylene was 183 g, corresponding to 18.3 kg per g catalyst. The average grain size d' was 370 µm, volume density according to DI^ 53 468 0.425 g/ml, trickle velocity V_ K 1 l0 n 8.2 cm^/sec. (DIN draft 53 492). The inolecular non-uniform a het (v M w /M n -1) ' was determined gel chromatographically as 23, the amount <M /5 to 45

Example 21.

a) Catalyst production.

183 g (1.06 mol) vanadyl(V) chloride and 258 g (1.06

mol) vanadyl(V)-n-propylate was stirred together in 1.77 1 of a hexane mixture 63/80°C for 1 hour at room temperature. This mixture and a solution of 620 g (4 mol) of isobutylaluminum dichloride in 3.45 1 of the hexane mixture 63/80°C added synchronously over 2 hours to 2 liters of the hexane mixture at 32 - 16°C while stirring with a blade stirrer and a specific stirrer power of 78 watts/m 3 . The formed suspension was then cniiu heated for 2 hours under reflux and thereby stirred with the same specific stirrer power.After cooling, the solid was separated and washed 5 times with each time 5 liters of the hexane mixture.

b) Copolymerization of ethylene and butene-(l).

The vanadium catalyst mentioned under example 21a

blo was used with triisobutylaluminum as Co-catalyst for the continuous polymerization of ethylene while adding small amounts of butene-(l). A 750 liter stirred tank was used as a polymerization reactor. The polymerization of the ethylene in a mixture with butene-(l) took place in a suspension of hexane-' lii.inding in the boiling range between 63°C and 80°C and powdered polymer as well as a catalyst . The filling level in the polymerization vessel was 300 1, and 2 hours was chosen as the average residence time of the catalyst in the polymerization vessel.

The copolymerization of ethylene and butene-(1) was carried out at a temperature of 75°C. In the gas space of the polymerization reactor, an ethylene partial pressure of 34.1 bar and a hydrogen partial pressure of 0.9 bar. The comonomer buton-(i) was compared to ethylene offered in weight ratio Ira 2 to 100. Catalyst and Cocatalyst were diluted in

(.mirror container in hexane 63/80°C and then added con-

tinuorly with a dosing pump for pol yrnerisa.s ion storage dereu. The concentration of the catalyst in the polymerization reactor was 3.33 mg/l suspension agent and Cokatalysa.to.ren 100 mg/l suspension agent. agent and dried in a partially evacuated container at approx. 80°C. The copolymer produced in this way had the following properties: Molecular heterogeneity

The numerically calculated consumption of catalyst by the above-mentioned method amounted to 37.1 mg V--katal v sa to r/kg polyethylene and 1,120 mg tri i sobu ty la 1 uiui n j.um/kg poly\ethylene. Volume te t t.lie ten of the copolyrne ri sateL determined according to DIN 53 •'■!(') 8 amounted to 0.4-52 g/ml. Sieve analysis gave an average grain size of 550 µm. When determining r i s I. e oven one according to DIN draft 53 '< 9 2, a trickle velocity V_ n- to 8.2 cm'V si A.C) was determined

sec ,

Claims (1)

Process for the production of powdered ethylene polymers, or copolymers of ethylene with small amounts of propene or butene-1, with high bulk density, good flowability, average grain diameter up to 1000 ura and practically without fine grain particles by polymerization in the presence of hydrogen in inert liquid hydrocarbons at temperatures between 50°C and 95°C and pressure from 10 to 100 bar, preferably 20-60 bar, by discontinuous or continuous process by means of Ziegler catalyst prepared in inert liquid hydrocarbons by reaction of chlorine- and alkoxy-containing vanadyl(V)- compounds with organoaluminum compounds, separation of insoluble reaction products and activation by arbitrary organoaluminum compounds, characterized in that 1: as vanadyl(V) compound, a reaction product of vanadyl(V) chloride and a vanadyl(V) alcoholate with 2-4 alkyl groups containing carbon atoms in molar ratios from 1:2 to 2:1 or direct reaction products of vanadyl(V) chloride with an al alcohol with 2-4 carbon atoms, preferably ethanol, propanol-(1), butanol-(1), in a molar ratio from 1:2 to 1:1, and 2: as organoaluminum compounds for reduction, ethylaluminum dichloride and/or diethylaluminum chloride or isobutylaluminum dichloride are used and /or diisobutylaluminum chloride in a zero ratio between aluminum and vanadium compound of 1:1 to 3:1, with 3: the reaction of the vanadium compounds with the organo-aluminum compounds being carried out under stirring with specific mre performances from 1-20,000 watts/m3, and 4: the activation takes place with aluminum alkyl compounds with the formula AIR^, in which R means alkyl groups with 2-8 C atoms or with alkyl aluminum sesquichloride and/or alkyl aluminum dichloride, especially ethyl aluminum sesquichloride and/or ethyl aluminum dichloride.