DE1808388C3 - 02/27/68 USA 708638 Process for the polymerization of ethylene - Google Patents

Description

InSI = k In

[A + ß]

+ Ine

in which Sl stands for the melt index of polyethylene, A is the hydrogen concentration in mol percent, B is the Athyien concentration in mol percent and k and c empirically determined constants for the particular, silica-applied bis (cyclopentadienyl) -chromdO catalyst, measured on a given catalyst concentration, a given catalyst surface area and a given polymerization temperature.

3. The method according to claim 1, characterized in that that one for the continuous production of solid polymers of ethylene, optionally together with a smaller amount of another '/ -olefin, at the same time

a) a gaseous stream containing the monomer or monomers with the finely divided bis (cyclopentadienyl) chromium (II) catalyst applied to a support in a polymerization zone, which consists of a fluidized bed and forming polymer particles, with one to the complete Vortex sufficient mass gas flow rate and a temperature below brings the sintering temperature of the solid polymer particles into contact,

b) from the polymerization zone a small proportion of the fluidized bed as discrete particles withdraws in suspension with part of the gaseous stream.

c) the unconverted portion of the gaseous stream is withdrawn from the polymerization / otic.

d) cools the unconverted, gaseous stream to remove the heat of reaction,

c) the cooled gaseous stream below the base of the fluidized bed at a for Maintaining turbulence sufficient- It is known that it is not possible with a bis (cyclopentadienyl) chromium (II) not applied to supports, without further treatment, e.g. B. Oxidation to initiate the polymerization of ethylene. If bis-icyclopentadienylj-chromfll) however brought into contact with an inorganic oxide with a high surface area in such a way that that it is absorbed (or deposited on the inorganic oxide, these two designations used interchangeably), it becomes an unusually effective catalyst for the Polymerization of ethylene in the absence of moisture and air over a wide range formed by reaction conditions. By polymerization of ethylene in the presence of one bis (cydopentadienyl) chromium (II) catalyst applied to a support it is possible to use either polyethylene. Copolymers of ethylene and others «To form olefins or crosslinkable copolymers from ethylene and diolefins.

The invention accordingly provides a process for the polymerization of ethylene, alone or together with a smaller amount of at least one other -olefin and / or a smaller amount Amount of at least one diolefin, at temperatures from 30 to 200 C and pressures from 1.4 to 56 atm in the presence of a catalyst made from an organochrome compound based on an inorganic oxide with high surface area is absorbed. which is characterized in that it is at the Organochrome compound around bis (cyclopentadienyl) chromium (il) or its substituted derivatives with one or more substituents on the cyclopentadienyl rings, which do not impair the catalylic effectiveness.

The process of the invention enables the formation of high yield polyethylene Molecular weight and narrow molecular weight distribution, which is practically free of internal and terminal, unsaturated bonds.

The process known from US Pat. No. 3,134,824 for the polymerization of ethylene in the presence of bis (cyclopentadienyl) nickel, which is applied to an inorganic oxide as a carrier, enables only the production of dimers. tetrameric or other oligomeric or liquid low molecular weight polymers. The from JA-AS 4741 / 1964. reported in Chemischen Zentralblatl, 1967. Issue 8. Referat 2977, known ethylene polymerization with catalysts made of dibenzene chromium on clay, SiO ₂ or aluminum silicate gives only relatively low yields. In addition, the polymers have a high vinyl content and a very high molecular weight which cannot be influenced with the aid of hydrogen.

On the basis of this state of the art, it could not be foreseen that during the application from bis (cyclopentadicnyl) chromium (II) to inorganic oxides with a high surface area

Yields of a polymer with a low vinyl content can be obtained and that the molecular weight with the help of hydrogen in the desired In a manner that can be regulated, as the examples and comparative experiments below show.

According to one embodiment, the method applies ier invention characterized in that one for the continuous production of solid polymers of Grain ethylene, possibly together with one Lot of another 'olefin, at the same time

a) a gaseous stream containing the monomer or monomers with the finely divided one bis (cyclopenladienyl) chromium (IIJ catalyst applied to a carrier in a polymerisation zone which consists of a fluidized bed of polymer particles which are formed and which are being formed, at a mass gas flow rate that is sufficient for complete turbulence and at a temperature below the sintering temperature of the solid polymer material brings,

b) from the polymerization zone a small proportion of the fluidized bed as discrete particles in Withdraws suspension with part of the gaseous stream,

c) withdrawing the unconverted portion of the gaseous stream from the polymerization zone,

d) cools the unconverted, gaseous stream to remove the heat of reaction,

e) to maintain the cooled gaseous stream below the base of the fluidized bed at one the fluidization returns sufficient speed to the polymerization zone and

f) additional monomer and catalyst imports according to consumption.

The additional catalyst is introduced into the fluidized bed above the bed base to create a to achieve rapid and uniform catalyst distribution over the entire bed.

In the polymer particles formed according to the invention the catalyst residue is not only non-corrosive, but also so small that the polymer particles directly without treatment for catalyst removal can be used.

Bis-cyclopentadienyl-chromill) can be produced by various processes. The most common is the reaction of sodium cyclopentadiene with chromochloride (see U.S. Patent 2870183) or the use of an excess of sodium cyclopentadiene with chromium chloride. Bis- (cyclopentadienyl) chromium (II) and its ring-substituted analogues can also be prepared by reacting cyclopentadiene or a substituted cyclopentadiene with chromo- (or chromium) chloride in the presence of diethylamine (cf. US Pat. No. 3,071,605 ). Bis (cyclopentadienyl) chromium (II), which has the empirical formula (C ₅ H ₅ ) ₂ Cr, is a reddish-purple compound with a crystalline form. It is easily oxidized and is very sensitive to air. Properties which require careful handling during the preparation of the deposited catalyst. <> s

To prepare the deposited catalyst, bis (cyclopentadienyl) chromium (II) is brought into contact with a practically anhydrous inorganic oxide with a high surface area under conditions such that the bis (cyclopentadienyl) chromium (II) is adsorbed by the inorganic oxide and is deposited on it. The various inorganic oxides that can be used to form a deposited bis (cyclopentadienyl) chromium (III) catalyst include silica, optionally hydrated SiO ₂ or silica, alumina, silica / alumina mixtures, thore, zirconia and the like Oxides; All of these carriers are chemically inert to bis-icyclopentadienyl-chromium (1). To be effective, these supports must have a high surface area to adsorb a sufficient amount of the bis (cyclopentadienyl) chromium (II) and to provide sufficient contact between the catalyst and the monomer. Usually inorganic oxides with a surface area between about 50 hi * 1000 m ² / g should be used as catalyst supports. The particle size of these carriers is not particularly critical, provided that the catalyst has a high surface area.

Since bis-fcyclopentadienylJ-chromdD also against If moisture is sensitive, the catalyst support should be dried completely before using the organic chromium compound is brought into contact. This is usually done by simply Heating or predrying the catalyst support with an inert gas before use. Surprisingly, however, it has been found that the drying temperature has a noticeable effect on the relative productivity of the catalyst system, on the molecular weight distribution and the melt index of the polymer produced.

Drying or activation of the support can be at almost any temperature to about the sintering temperature for a period performed we ^r the at least sufficient to remove the adsorbed water, however, avoids that all chemically bound water is removed. An inert gas stream passed through the carrier during drying expediently supports this treatment. Temperatures of about 200 to 900 C for a short period of about 6 hours should be sufficient if a well-dried, inert gas is used and the temperature is not allowed to rise so high that all chemically bonded hydroxyl groups on the surface of the support are completely removed .

According to the invention, all types of carrier can be used, although microspheroidal, gold-density silica with a surface area of 258 m ² / g and a pore diameter of about 288 Å and medium-density silica with the same surface area but a pore diameter of 164 Å are preferred. Other types, such as B. silica and silica / alumina with surface areas of 700 and 500 m ² 'g and pore diameters of 50 to 70 Å are also quite satisfactory. Changes in melt index control and polymer productivity can be expected for the various types of carrier.

After formation of the deposited bis (cyclopentadienyl) chromium (II) the polymerization takes place by adding the ethylene, in virtually the absence of Moisture and air, with a catalytic menu of the deposited bis- (cyclopentadiene vl) -chrome! H) catalyst brings in touch. If necessary, an inert, organic solvent can be used as

thinners and for easier handling of the Materials are used.

The polymerization takes place at temperatures of 30 to 200 C, depending on the working pressure. the pressure of any other olefin monomers used, the particular carrier and the Catalyst concentration. Of course it depends the selected working temperature also depends on the desired melting point of the polymer, since the temperature is a decisive factor in setting the molecular weight of the polymer. Preferably the temperature is about 30 to 100 ° C "for conventional suspension processes and 100 to 200 ° C in solution polymerization. As explained in more detail below, the temperature control is useful in this process by having various effects on the molecular weight of the polymers as well as in the regulation of the phase in which they are produced. As with most Catalyst systems deliver the higher temperatures polymers with lower, weight, average molecular weights and therefore higher melt index. When working at the higher polymerization temperatures are actually polymers with a melt index of 100 up to 1000 or more possible, which can be identified as waxes.

The pressure used is 1.4 to 56 atmospheres.

The inert, organic solvent medium which can be used according to the invention is not very critical, should, however, be compared with the deposited bis (cyclopentadienyD-chromium (II)) catalyst and the olefin polymer formed be inert and stable at the reaction temperatures used. It is but not necessary that the inert, organic solvent medium also as a solvent for the polymer formed acts. Inert organic solvents suitable for this purpose are e.g. B. saturated aliphatic hydrocarbons such as hexane, heptane. Pentane. lsooctane or purified kerosene, saturated cyclocycloaliphatic hydrocarbons, such as cyclohexane, cyclopentane, dimethylcyclopentane or methylcyclohexane, aromatic hydrocarbons such as benzene, toluene or xylene, and chlorinated ones Hydrocarbons such as chlorobenzene, tetrachlorethylene or p-dichlorobenzene. Particularly preferred solvent media are cyclohexane, pentane and hexane and heptane.

It is preferred to carry out the polymerization as above mentioned to perform on a high solids content, the solvent should of course expediently be liquid at the reaction temperature. When working at a temperature below the solution temperature of the polymer in the solvent the process can, for example, be practically a suspension polymerisation process in which the polymer actually precipitates from the liquid reaction medium and in which the catalyst in finely divided form is suspended.

This slurry system depends, of course, on the particular one involved in the polymerization solvent used and its solution temperature for the polymer produced. Therefore, in the "finely divided form" embodiment, it is most appropriate at one temperature to work under the normal solution temperature of the polymer in the selected solvent. So has z. B. In accordance with the invention, produced PoIsäthylcn a solution temperature in cyclohexane of about 90 C. while its solution temperature in Pentane is about 110 ° C. It is a mark S of this polymerization system with »finely divided particles ··. that a high polymer content is possible even at low temperatures. provided, that stirring is used to ensure sufficient mixing of the monomer with the polymerizing agent

ίο enable mass. Although the polarity wedge can be a bit slower at the lower temperatures, it seems. that the monomer is more soluble in the solvent medium. causing a tendency to low speeds and

i <j or low yields are counteracted by wiro.

It is also characteristic that the monomer evidently plays an important role in solubility even in the solid portion of the slurry. so that a wider size range of solid particles

ίο can be created in the slurry. while stirring and the polymerization temperature is maintained. Experiments have shown that the slurry process can form systems with greater than 50% solids, provided that sufficient fluidizing and agitation conditions are maintained. It is particularly advantageous to operate the suspension process with a polymer solids content of 30 to 40 percent by weight.

The recovery of the polymer from the solvent medium is used in this embodiment simple filtering off and drying simplified, with no polymer purification and catalyst separation or cleaning becomes necessary. The remaining catalyst concentration in the polymer is like this little in that one usually finds less than 2 or 3 parts of chromium per million parts of polymer. Residues at such values are in the polymer insignificant and not noticeable; they can remain in the polymer.

Also working at temperatures above the solution temperature of the polymer in the selected Solvent medium can have a high polymer solids content result in the solution. The temperature in this embodiment must be high enough so that the solvent to Dissolving at least 25 to 30 percent by weight of the polymer can be used. Against it must the temperature must be low enough to allow thermal degradation of the polymer formed and of the to avoid special bis (cyclopentadiene}!) chromium (II) catalyst used. For the ver The various solvents used and the bis (cyclopentadienyH-chromium-UH catalyst) have siel

usually temperatures of 100 to 200 C, preferably from 120 to 170 C, as optimal for through management of such a solution polymerization he showed. However, the special also made it Polymer has a significant influence on the opti

male temperature. So are z. B. after this Vei drive produced ethylene-propylene copolymers sate is soluble in many of these low temperature organic solvents, and therefore di Use of such temperatures according to the invention

permissible, although this is for optimal manufacture Polyäthylenhomopolymerisaten or -mischpol} merisalen need not be appropriate. Solvents are one of the most essential un

most troubling sources of catalyst poisoning. Farther was used in known solution polymerization processes when using catalysts with transition metals, the use of large amounts of solution, d. H. a ratio of solvent to polymer of around 20: 1 is deemed necessary. A such a large proportion of solvent necessarily increased the problem of catalyst poisoning substantially. In the process according to the invention, however, the ratio of solvent to polymer can be only 1: 1 or even less, resulting in a very high catalyst productivity and effectiveness of the system is maintained.

If the solvent is used as the main reaction medium, it is of course appropriate to the solvent medium is practically anhydrous and free of any possible catalyst poisons to keep by redistilling or otherwise before use in the process of the invention cleans. Treatment with an absorbent such as B. Silicas, clays, molecular sieves and similar high surface area materials is beneficial in removing trace amounts of impurities that reduce the rate of polymerization or the catalyst may poison during the reaction.

However, it is optionally also possible to carry out the polymerization without an added solvent reaction medium perform. So the liquid monomer itself can e.g. B. be the reaction medium, either with the normally liquid monomers, as in the production of ethylene-propylene copolymers using liquefied propylene and other similar ones normally liquid monomers, or by working under sufficient pressure so that the normally gaseous monomers are liquefied.

The fact that the rate of polymerization remains high, even at the high viscosities associated with high solids, is unexpected. It is particularly surprising and unexpected that the reaction rate remains high when gaseous monomers such as ethylene and propylene are used. According to the invention, however, it has been found that high polymerization rates are maintained even when these gaseous monomers are used at pressures below 7 atmospheres if the reaction solution is constructed by means of a high-speed, high- shear stirrer, particularly a stirrer operated at speeds above 2000 revolutions / min can impart substantial shear to the solution, is stirred.

Another particularly important advantage of this embodiment of the process according to the invention is that the polymer solution with a high solids content is suitable for polymerisation isolation by grinding and rolling processes after the end of the polymerisation without any further treatment (cf., for example, US Pat. No. 24 34 707) is. The “Marshall mill” is most expediently operated with the polymer-solvent mixture to be treated with a high polymer content. The use of such a closed device also enables all or part of the separated solvent to be returned to the polymerization vessel without contact with oxygen or atmospheric water vapor, which are detrimental to many of the catalysts containing transition metals.

A further advantage of the process according to the invention is that the catalyst and the polymer formed can be kept in homogeneous solution in the solvent medium. By avoiding the formation of a polymer suspension, s ^; The reaction mass surprisingly looks like a viscous, flowable material that can be pumped and handled by conventional methods for handling the same.

Another advantage of the polymer which is soluble in the diluent is the possibility of Use of high reaction temperatures. This is not practical, as the high temperatures reduce the viscosity of the solution, making the polymerization faster and more effective removal the heat of reaction is possible due to the larger temperature differential between the Reaction vessel and the cooling water. The molecular weight of the polymer can also be regulated be, since higher reaction temperatures usually the formation of polymers with lower Cause molecular weight. This latter factor is particularly important in the manufacture of Waxes with a high melt index, as shown in the following examples.

The separation of the polymer from the solvent medium is not limited to the use of a high shear rolling device, although a Marshall mill has proven to be very suitable and preferred in accordance with the invention will. However, it is also possible. Precipitation and filtering process to obtain the polymer apply or the polymer / solvent mass by flash evaporation or others Concentrate means of solvent removal, to which the rolling or grinding with high Shear force connects. It is a number of others.

suitable rolling devices with high shear force available, and due to the low solvent content the solution to be treated are also other devices, such as ventable extrusion presses, calender roll mills, Planet Rolor Mills. how they z. B.

in US Pat. No. 3,075,747, or Banbury mills can be used successfully to isolate the polymer product. The term "roller frame (mill) with high shear force" used in the following refers to a device made up of parallel rollers with intermeshing threads; the terms "high shear conditions" and "high shear conditions" mean those that are achieved on a high-shear roller mill or by sufficiently driven, high- speed mixers for viscous materials. Of course, the high solids system can be used with the catalyst suspended in the solvent provided the necessary conditions of agitation.

Pressure and temperature are maintained to keep the monomer in contact with the catalyst and provided that the pressure and temperature are sufficient to cause the polymerization introduce this monomer to the polymer.

The amount or concentration of the deposited bis (cyclopentadienyl) chromium (II) catalyst is not critical and usually only affects the rate and yield of the

60964V95

obtained polymer. You can / between about 1 and 100OuO parts by weight of catalyst, based to the 1 million parts by weight of imported Oiefins. .Ic lower the penalty for pollution is in the reaction system. Of course, the lower the catalyst concentration used being. Tests have shown that yields over 300,000 parts of polymer per part of bis (cyclopentadienyl) chromium (II) can be obtained. For these catalysts, the weight is the The carrier is usually about 10 to 100 times the weight of the organic chromium compound. This However, the ratio is not critical and can be varied widely.

The olefins which can be polymerized with ethylene according to the invention include those with 3 to about 10 carbon atoms, such as B. propylene. Butcn- (l). Pentene- (l). 3-methylbutene- (l), hexene- (l). 4-methylpentene- (l). 3-ethylbutene- (l), heptene- (l). Octene (l). Decen- (l). 4,4 - Dimethylpentene - (1), 4.4 - Duithylhexen- (l), 3,4-dimethylhexene (1), 4-butyl-1-octene, 5-ethyl-1-decene and 3,3-dimethylbutene- (1). These compounds can be used in combination with a Main amount of ethylene to normally solid, high molecular weight copolymers of ethylene and one or more -olefins are polymerized. Ethylene (alone or with a few minor Amount of other -olefins) can also be used with a diolefin to form normally stronger, more crosslinkable Interpolymers are polymerized. Usable diolefins include butadiene. 1.5-hexadiene. Dicyclopenladien and ethylidene norbornene. The production of ethylene homopolymer is, however, particularly preferred. Preferred Mixed polymers contain a major proportion of mixed polymerize! Ethylene together with a lesser proportion of another monomer. Particularly preferred copolymers are Ethylene-propylene or ethylene-butene copolymers with up to 20 percent by weight of mixed-polymer propylene or butene.

During the polymerization care should be taken that neither moisture. Air still oxygen is stirred in, which are all catalyst poisons.

By carrying out the polymerization in the presence of hydrogen, which acts as a chain transfer agent acts, the molecular weight of the "polymer" regulated and the yield of the polymerization The hydrogen addition to the system surprisingly increases the activity of the catalyst, because comparative tests have shown that under identical reaction conditions the presence of hydrogen in the polymerization the productivity of the catalyst (kilograms produced Polymer per kilogram of catalyst) up to 20 ° ο increased

Experience has shown that hydrogen m the Polymerization in different amounts between about 0.001 and about 10 moles of hydrogen per mole of ethylene can be used for most Polymerizations can have a narrow molecular weight distribution can be obtained by using about 0.001 to 0.5 moles of hydrogen per mole of ethylene In other words, the preferred hydrogen range is 0.1 to 50 molpro / ent. based on ethylene.

If Äthvlen in solution * - or Suspensionssy- '. Temcn using a deposited Bi> (cyclopentadienyl) chromium (II ! -Catalyst homopolymcrisicrt. then the ratio of the speed is of the polymer to the hydrogen and ethylene concentration used in the polymerization - such as was determined by the following equation:

InSl

AIn

M + B]

4 hit

Sl stand for the melt index of polyethylene. A for the hydrogen concentration in mol percent, ß for the ethylene concentration in mol percent, k and c are empirically determined constants for the particular, deposited bis (cyclopentadicnyl) chromium (II (catalyst, which was used in the polymerization.

The constants will be for the catalyst at a given catalyst concentration. Carrier surface area. Determined temperature of carrier activation and polymerization temperature. So is z. B. with a bis (cyclopentadienyl) chromium (ID catalyst on silica, produced by adsorption of 6 parts by weight of bis-1cyclopentadienyD-chiomfll) to 94 parts by weight of medium-density silica with a surface area of 258 nr g and a pore diameter of 164 Å (previously dried for 24 hours in a nitrogen atmosphere at 650 C) the ratio between the melt index of the polymer and the hydrogen and ethylene concentrations Carrying out the polymerization at 90 C:

Sl

(3.39- CP)

A + B]

This fact is shown in FIG. 1 szezciut. By correct choice of a special, deposited bis-lcyclopentadienyD-chroml I D catalyst and the The polymerization yields a polyethylene with a predetermined concentration of hydrogen and ethylene Melt index and a narrow molecular weight distribution that is practically free of internal and terminal unsaturation.

The polymerization of Äthvlen with the inventive Catalysts used in a fluidized bed reaction vessel are illustrated by the following description and FIG. 2 further illustrates in dei the schematic working of an inventive:

the vortex reactor used in this way is shown. "

By using the B] s- (cyclopentadienyl) -hrom (] D catalysts applied to supports, it is possible to NEN under the conditions specified below for a fluidized bed reaction vessel ethylene homo

ss polymers formed as well as polymers by poly mcnsieren von Äthvlen with .. olefins with about 3 bi 8 carbon atoms, which are gaseous at the polymerization temperature and with Äthvlen at one Temperature below the sintering temperature of the received

ho ten polymer are polymerizable, under Bi dung dry, finely divided resin particles, which u are essentially free of low molecular weight calves and fats In this way the formation of polymers

hs like statistical copolymers or specia polymers possible. So z. B. different monomers one after the other in a single vortex for the formation of block mixed polymers

will. Furthermore, you can resin from a reaction vessel containing a monomer through a suitable valve into a reaction vessel containing another monomer with only insignificant The monomer is carried along by a reaction vessel transfer into the other. This latter method is also particularly effective for education of mixtures of polymers. Both alternatives are particularly suitable for the formation of block copolymers and mixtures of polymers made from monomers with different reactivity.

The supported catalysts are in the form of a concentrated slurry of Particles or as powdery, free flowing solid particles used in the manner described above. The deposited catalysts can expediently still be subdivided; Subdivision is the ability of the catalyst particles to grow in the presence of one To break polymer and thereby itself with the formation of many particles of low catalyst residue to stretch from a single catalyst particle.

The divisible, deposited catalysts for the fluidized bed reactors are preferably produced, by bis-lcyclopentadienyH-chromOI) deposited on a porous support with high surface area. When packed in a porous With high surface area carriers, the catalyst forms active sites on the surface and in the ^ o Pores of the carrier. Without wishing to be bound by any theory, it is believed that the polymer begins to grow on the surface and in the catalyst pores. When a porcn-grown polymer is large enough. breaks it on the carrier and thus releases further catalyst sites in the inner pores of the carrier. The deposited catalyst is divided somi! during his life in bed many times and dadurc'.i improves the production of polymers with low catalyst residue, eliminating the need for catalyst recovery is eliminated from the polymer particles. If the carrier particles are too large, they can cause you Resist breakage and thereby prevent subdivision, thereby wasting catalyst arises. Furthermore, carrier particles that are too large can act as a heat trap and prevent formation Cause "hot spots".

The deposited catalysis can be removed by cm Slurry process can be prepared in which a selected and appropriately dried support under conditions that require the presence of Exclude air and moisture, to one of the bis (cyclopentadienyl) chromium (II) and a solution containing a solvent to form a slurry is added. The slurry can be stirred for up to about 4 hours. to be good Adsorption of bis (cyclopentadicnyl) chromium (lli to be obtained by the carrier. The solvent is then stripped off the slurry and the catalyst is used per se, or the retained solvent can be used under conditions which exclude oxygen and moisture, for formation a dry one. puKengcn catalyst are evaporated on a support

The dry catalyst can also expediently ■ η the absence of a solvent by direct Vapor deposition (sublimation) of bis- (cvclopenladicnyl) -chroms (ll) can be prepared on a dry carrier. This is done simply and appropriately by mixing the crystalline bis (cydopentadienyl) chromium (ll) and the support under a dry inert atmosphere, followed by printing for sublimation and adsorption of the bis (cyclopentadienyl) chromium (II) on the support is reduced.

The dry His- (cyclupentadicnyl) -chrom (II (-catalysts If made correctly, they are dark rol and sometimes almost black. In case of poisoning by oxygen. humidity or some other impurities they turn green. The catalyst color is therefore your own Quality control.

F i g. 2 shows a vortex action system used according to the invention. With reference to FIG. 2 the reaction vessel 10 consists of a reaction zone 12 and a zone for reducing the speed 14th

The reaction zone 12 consists of a bed of growing polymerisals, formed polymerisates and a small amount of catalyst which are swirled by the continuous flow of polymerisable and modifying gaseous components in the form of additional feed and recycle gas through the reaction zone. To maintain a viable vortex, the mass gas flow through the bed is above the minimum flow necessary for the vortex. preferably used between 2 and about (mial G, "or more particularly between about 3 and? ( '' if '(' mi ^{w 'r} d ⁱⁿ this form as an abbreviation for the amount necessary to Hrzielung turbulence Mindcsimassengasfluß (\ gl CY, Wen and YH Yu, Mechanics of Fluidization, Chemical Engineering Progress Symposium Series, Vol. 62, pp. 100 to IU [19661). "

It is essential that the bed always light up to avoid the formation of localized "hot spots" and to pick up and distribute the powdery catalyst by the Rcaktions / onc contains. At the start of the proceedings, the reaciioiiszonc usually with a base of finely divided polymer particles before starting the (Jasflusscs coated. The particles can in their type the / u Hildendcn polymer identical or different from this. If they are different, they will deducted when the desired Pohmcnsatteikhcn as the first product to form. Gradually a fluidized bed of the desired particles replaces the Λη fangsbelt.

The catalyst concentration in the bed is practical equal to the catalyst concentration in the product, namely in the order of about 0.005 bi 0.50% of the bed volume.

The katal \ sau> i win used in the Wirbeibelt preferably for use in a container 3! stored under a nitrogen atmosphere

The swirl is achieved by cmc height The rate of gas recirculation to and through the bed, which is usually about 50 times the Bt Dispatch speed of the additional guest amounts to. The fluidized bed usually has the appearance of a dense mass of volatile parts chcn in the most vortex-free river, as he thruc the percolation of the gas through the bed is formed The free must of the particles and then the Ve

vortices are confirmed by the fact that the axial pressure drop across the bed is usually only by about 0.07 atm.

The extra gas w.jd the bed at one speed fed, which is equal to the speed with which the finely divided polymer product is deducted. The composition of the additional gas is determined by a gas analyzer 16 above the bed. The gas analyzer determines the absence or insufficient presence of a component in the returned Gas, and the composition of the additional gas is adjusted accordingly to maintain a practically uniform composition within the reaction zone.

To ensure complete turbulence, the recycle gas and, if necessary some of the additional gas is returned to the reaction vessel at point 18 below the bed. To the There is a gas distribution base above the return point for better fluidization of the bed 20th

The portion of the gas stream that does not react in the bed represents the recycle gas that emerges from the polymerization zone is removed, preferably by placing it in a decelerating zone 14 above the bed directs where those who were brought along Particles have the opportunity to fall back into bed. Particle recirculation can be done by a cyclone device 22 may be supported forming part of the speed reduction zone can be or can be outside the same. If necessary, the recycle gas can then passed through a filter 24 to remove small particles at high gas flow rates, thereby avoiding dust with the heat transfer surfaces and compressor blades comes into contact.

The recycle gas is then passed through a heat exchanger 26, in which before the Returning to the bed, the heat of reaction is removed. By constantly removing the heat of reaction there appears to be no noticeable temperature gradient within the bed. It was in particular it is observed that the bed causes the temperature of the recycle gas to adjust almost immediately to that of the temperature of the bed to allow it to conform, making it even at a practically constant temperature under uniform Conditions. The recycle gas is then compressed in a compressor 28 and returned at its base 18 to the reaction vessel and through the distribution tray 20 to the fluidized bed.

The distribution tray 20 plays an important role in the operation of the reaction vessel. The fluidized bed contains growing and formed, finely divided polymer particles and catalyst particles. Since the Polymer particles are hot and possibly active, they must not settle because if you creates a resting mass, any active catalyst contained therein can continue to react and cause a merger. Hence there is diffusion of the recycle gas through the bed important at a speed sufficient to maintain turbulence at the bed base. The distribution tray 20 serves this purpose; it can be a sieve or a slotted or perforated one Be plate. Regardless of its construction, it must pass the recycle gas through the particles to the Bed base conduct to keep them viable and also to support a dormant bed of resin particles to serve when the reaction vessel is not in use.

Hydrogen as a component of the gas flow is of equally decisive importance in vapor phase polymerization in the fluidized bed reaction vessel

ίο as in the more common systems. In vapor phase polymerization the melt index of the product is relatively unaffected by the temperature, as there is a moderate change in the working temperature causes no noticeable change in the melt index. Therefore one has to look for an alternative for that if necessary, use the desired modification of the melt index. It was found that hydrogen affects the melt index in the product. As mentioned above, the melt index of the increases Product with the hydrogen concentration in the gas stream.

Hydrogen also increases the activity of the catalyst, because comparison tests have shown that under identical reaction conditions the presence of water in the polymerization increases the productivity of the catalyst (kilograms of polymer produced per kilogram of catalyst) by up to 20%.
Experiments have shown that hydrogen can be used in the polymerization in amounts between about 0.001 and 10 mol of hydrogen per mol of ethylene. For most polymerization reactions, a narrow molecular weight distribution can be achieved by using from about 0.01 to 0.5 moles of hydrogen per mole of ethylene.

In the production of copolymers from ethylene and propylene or other monomers with low reactivity has also been found to reduce the reactivity of the Improved monomers with lower reactivity.

If desired to regulate the system, so can

each against the catalyst and the reaction

inert gases must be present.

It is critical that the fluidized bed reactor be operated at a temperature below the sintering temperature of the polymer particles. To ensure that sintering does not occur, working temperatures well below the sintering temperature are desirable. For the preparation of homopolymers an operating temperature of about 70 is preferably ⁰ to 110 C, while for copolymers an operating temperature of about 90 ° C or less is preferred.

The process is carried out at a pressure of about 2.8 to 21 atmospheres or more, with a Working at medium and high pressures favors the heat transfer, since a pressure increase the unit volume of heat capacity of the gas is increased.

The catalyst is introduced into the bed at a point 30 above the distribution tray 20 at a rate equal to its consumption. Ier is preferably introduced at a point which is at etwai ¹ U to _^3/4 of the bed height. The introduction of the catalyst at a point above the distribution tray is an important feature of the invention. Since the catalysts used according to the invention are extremely active, the introduction into the field

cause the start of polymerization there below the distribution tray and gradually commence Clog the distribution base. The introduction into the bed, on the other hand, supports the catalyst distribution by the BeU and prevents the formation of localized sites with a high catalyst concentration, which can lead to the formation of "hot spots".

All or part of the additional feed stream is used to make the catalyst to lead into the bed. Preferably only part of the additional feed stream is used as Carrier door uses the catalyst, since at high productivities the introduction of large amounts of gas into the side of the bed interrupt the bed properties and cause channeling, etc. can. Alternatively, a portion of the recycle gas stream can also be diverted to the catalyst to lead into the bed.

Bed productivity is only made by speed determined by the introduction of the catalyst. It can be done by simply increasing the rate of catalyst introduction increased and decreased by decreasing them.

As any change in the catalyst introduction rate a change in the rate of formation of the heat of reaction is caused adjust the temperature of the recycle gas up or down to accommodate the change in speed to compensate for the heat build-up. This ensures the maintenance of a practically constant Bed temperature. A complete set of instruments for both the fluidized bed and the Cooling system for the recirculation gas is of course to detect any temperature change in bed necessary for the operator to make an appropriate setting in the temperature of the recycle gas can make.

Under a given scheme of working conditions, the fluidized bed will be at a practically constant Maintained height by moving part of the bed as a product at the same rate as the rate of formation of the divided polymer product withdraws. Since the rate of heat generation is directly related to product formation, a thermal analysis of the is The gas leaving the reaction vessel provides an indication of the rate of formation of the finely divided Polymer.

The finely divided polymer product is preferred continuously at point 34 or near the distribution tray 20 in suspension with a Part of the gas stream withdrawn, which is vented before settling of the particles, for further polymerization and preclude sintering when the particles reach their final collection / zone. The Suspending gas can also, as mentioned above, be used to remove the product from a reaction vessel to lead into the other.

The finely divided polymer product becomes / awkward and preferably by sequential operation of a pair of timers. a segregation zone 40 limiting valves 36 and 38 ahgeioeen. While valve 38 is closed. valve 36 opens and inputs a gas and product amount the zone 40 between it and valve 36, which then closes. Valve 38 opens to the product to be released into an outer extraction zone, whereupon it closes! and wait for the next round.

Finally, the fluidized bed reaction vessel is provided with a sufficient venting system to to enable ventilation of the bed during the beginning and end of the process.

The bis (cyclopentadienyl) chromium (II) catalyst system used according to the invention and applied to a carrier provides a fluidized bed product with an average particle size between about 0.42 and 0.15 mm, in which the catalyst and support residue is unusually low.

By working in the fluidized bed reaction vessel found various advantages over conventional suspension and solution processes.

It is important that the polymer does not appear to have any tendency to coat the walls of the reaction vessel consists. The formation of a polymer coating on the walls of a suspension and solution reaction vessel is a relatively uncontrollable and unpredictable phenomenon that is heat transfer hinders and causes polymer lumps to "break off" or get into the system. Based on productivity, the fluidized bed reactor has reduced installation and operating costs.

He is also more stable as he tends to be all sudden To dampen changes in working conditions, of course. When working in a fluidized bed reaction vessel there seems to be more leeway.

Finally, there is an essential advantage in the improved regulation of the gas composition. the Gas composition in slurry and solution reactors is due to monomer solubility and diffiusivity limited. Because in the fluidized bed reaction vessel no liquids are present, the gas composition is practically infinitely variable, and the practical or actual gas composition is only determined by the relative reactivities of those present Affected monomers.

The following examples illustrate the preparation of the catalysts and their use in common polymerization systems and fluidized bed reaction vessels and still show the properties of the polymers produced according to the invention.

The properties of the polymers produced in the examples were determined according to the following test methods definitely:

Density: ASTM D-1505, the plate was conditioned for 1 hour at 120 "C to get as close as possible an equilibrium crystallinity to come. Melt Index (M /): ASTM D-1238, measured at 190 C and given as grams per 10 minutes.

Flow Rate (HLMI): ASTM D-1238, measured at 10 times the weight used in the melt index above.

■ 'let \ erh; ilinis

Flow rate melt / .index

Stiffness: ASTM D-63X.

Tensile Shock: ASTM D-256 Not Notched

Sample was subjected to an Izod impact tester in such a manner clamped that it broke when tensioned.

08

10

Pre-activation temperature of the support

(C)

465 580 670

example 1

In an autoclave 500 cc of dry hexane and 0.4 g of medium-density silica with oner surface area of 258 m were ² / g and a pore diameter of 164 Å (before heating for 24 hours by si! A nitrogen atmosphere to 58o C ⁰ activated) was added. After thoroughly flushing the keaiclion vessel with argon, 2 ecm ? ^ar W was ^c J ° ~ pentadienyl) chromium (II) was added in solution with hexane (5 mg / cc), after which sealed the ReaktionsgefaB and heated to 70 ⁰ C. At this temperature, the autoclave was pressurized with ethylene aui a pressure of 14atü set . Ethylene was introduced as required for the duration of the polymerization in order to maintain a pressure of 21 atmospheres,

receive. After 30 minutes, a long polymerization table ^ at 70 ⁰ C the Äthylennuß was discontinued and the reaction vessel vented and then opened. The reaction yielded 100 g of polyethylene with a melt index of 0 and a flow rate of U. The polymer contained practically no branching (the methyl content was determined by infrared and was less than 0.1%) and practically no unsaturation (ie less than 0.03) / 0). ^

Example 2

Example 1 was repeated, but the reaction vessel at 70 C with hydrogen on one Pressure of 2.1 atü was set. Then ethylene was added to the reaction vessel until the Total pressure of hydrogen and ethylene reached 21 atu. After 30 minutes the polymerization started stopped by venting the reaction vessel and gave 120 g of polyethylene with a Melt index of 1.7 and a flow rate of 73. The addition of hydrogen increased catalyst productivity by 20%, which is shown by the higher polyethylene yield compared to Example 1 would. Example 3

According to Example 1, ethylene was polymerized in the presence of a bis (cyclopentadienyl »chromium (11 (catalyst) deposited on silica, but 30 mg (C, H,) ₂ Cr were used At this temperature the polymerization proceeds in solution. After 15 minutes of polymerization 60 g of polyethylene with a melt index of 19.5 and a flow rate of 486 and with 0.30 percent by weight of transunsaturated bonds and 0.10 percent by weight of unsaturated vinyl bonds were obtained.

B e i s ρ i.e 1 5

Table 1 shows the change in the melt of the polyethylene with the change in the temperature of the support. The deposited jienyl) chromium (II) catalyst was produced by adsorption of 10 mg (C ₅ H ^ ₂ Cr on Sg medium-density silica with a surface area of 258 m ² / g and a pore diameter which had previously been stored for 24 hours in a nitrogen to the temperature given below. Each polymerization took place under a hydrogen pressure of 2.1 atmospheres and a total pressure of 14 atmospheres. The polymerization time was 30 minutes.

Melt index

0.30
1.70
2.70

Example 6

Feet mdiukcit

13th

73

119

B e i s ρ i e 1 4

According to Example 3, polymerization was carried out at 155 to 160 ° C. under 31.5 atmospheres of ethylene pressure. The catalyst consisted of 30 mg (C ^ H ₅ I ₂ of Cr and 0.4 g forher IS hours at 760'C activated mikroiphäroider mitleldichler silica with a Obcrfläcliengehiel of 258 in ² g and a Porendurchtnesscr of 288 A. After 30 minutes, a long polymerization were 61 μ obtained a low molecular weight wax which was too flowable for a melt index determination. This wax contained 1.65% by weight of internal trans-unsaturated bonds and 11.42% by weight of unsaturated vinyl bonds.

Ethylene and propylene were copolymerized as in Example 1, but the Reakt.onsgefaß was adjusted to a pressure of 14 atmospheres with hydrogen and 4.9 atmospheres with propylene and ethylene was added up to a total pressure of 14 atmospheres. After 30 minutes, a long polymerisation "1 Hon at 7O ⁰ C. 36 g of copolymer having a melt index of 1.1 and a flow rate of 42 were obtained. The methyl content of the resin by IR method was 0.79 (corresponding to 1.55% by weight of incorporated propylene). The copolymer had a density of 0.932.

Example 7

Ethylene and ethylidene norbornene were copolymerized as in Example 1, but after the addition of (CHs) ₂ Cr, a total of 10 ecm of alhylidene norbornene were added to the reaction vessel. After 60 minutes of polymerization, 100 g of copolymer with a melting index of 0.1 and a flow rate of 14 were obtained. The resin obtained contained 0.97 percent by weight methyl. The density of the copolymer was 0.947.

Example 8

In a continuous reaction vessel two homopolymers were prepared from ethylene (A and B) The solvent was isopentane, and the Hb elagerte catalyst consisted of 94 weight percent mitlcldichter silica having a surface area of 258m ^2/2 and a pore diameter of 164 A (before 24 hours dried in an N, atmosphere at 65O ^l C) and 6 percent by weight bis-1cyclopentadienyO-chromOI). The polymerization conditions and the properties of the two polymers are summarized in Table II:

Table Π

Ethylene concentration B e i s ρ i 20.0 19.5 14.5 (Mole percent) 0.9745 Hydrogen concentration 0.16 0.34 (Mole percent) Reaction vessel pressure 31.5 31.5 (kg / cm ² ) Reaction vessel temperature 90 90 (<■ ->
Catalyst productivity more than 7000 ku Resin per Kilo- ~ grams of catalyst Melt index 1.15 density 0.9698 el 9

Example 11

500 ecm of dry hexane were placed in a 1-1 autoclave. The reaction vessel was placed under a continuous stream of argon, whereupon 0.4 g of medium-density silica with a surface area of 258 m ² / g and a pore diameter of 164 Å (predried in a nitrogen atmosphere at 550 ° C. for 24 hours) was added. Then 10 mg of bis (cyclopentadienyl) chromium (II) was introduced into the reaction vessel, and this was sealed and heated to 85 ° C. The autoclave was vented and pressurized to 3.5 atmospheres using hydrogen. The reaction vessel contents were stirred for 30 minutes at 90 C ^c. The excess hydrogen pressure was then released, and the reaction vessel was adjusted to a pressure of 14 atmospheres with ethylene. Ethylene was introduced as needed to maintain a pressure of 14 atmospheres throughout the polymerization. After one hour of polymerization, 37 g of polyethylene with a melt index of 0.13 and a flow rate of 0.15 were obtained.

Example 10

500ccm of dry hexane and 0.4 g of medium-density silicic acid with a surface area of 258 m ² / g and a forum diameter of 164 A were placed in a 1-1 stirred autoclave continuously flushed with argon, which had previously been added for 46 hours by vortexing in nitrogen at 550 ° C had been dried. Using an injection needle, 5 mg of bis (cyclopentadienyl) chromium (II) were introduced in the form of a hexane solution (5 mg / ccm). The bis (cyclopcntadienyl) chromium (II) had previously been prepared in tetrahydrofuran according to the process described in Zeitschrift für Naturforschung 90, 417 (1954). After the bis (cyclopentadienyl) chromium (l I) had been introduced, the reaction vessel was closed, heated to 90 ° C., then vented and pressurized with ethylene to 14 atmospheres. During the 30 minute reaction time, ethylene was introduced as needed to maintain the pressure at 14 atmospheres. After the polymerization, the ethylene supply was stopped and the reactor was cooled to 70 ° C., vented and taken apart. The yield of dry polyethylene was 60 g; its flow rate. 5 g of silica alumina were added, which had previously been dried for 18 hours at 500 ° C. Then 20 mg of bis-1cyclopentadienyO-chromium were introduced and the reaction vessel was sealed

ίο ethylene brought to a pressure of 28 atm. While Ethylene was introduced into the reaction as needed to keep the pressure at 28 aiu. In Polymerization at 90 to 115 ° C. for 45 minutes gave 165 g of polyethylene at one flow rate received from 0.

Example 12

According to the example! 10 ethylene was polymerized.

however, the reaction vessel at 85 C with hydrogen was brought to a pressure of 2.1 alü. After the reaction vessel temperature reaches 90 ° C had, was adjusted with ethylene to a total pressure of 14 atm. After 30 minutes of polymerization at 90 ° C., 70 g of polyethylene were obtained with a melt index of 1.64, a flow rate of 85.5 and a density of 0.945. The resin was almost free of unsaturation (the IR spectrum only showed traces of absorptions at 10.4 and 11.0 μ).

Example 13

According to Example 12, ethylene was made under hydrogen pressure of 3.5 atmospheres (total pressure 14 aluminum) polymerized. After 30 minutes of polymerization At 90 ° C., 64 g of polyethylene with a melting index of 24.0 were obtained.

Example 14

According to Example 12, ethylene was made under hydrogen pressure polymerized from 2.1 atmospheres (total pressure 14 atmospheres) at 70 ° C. After 60 minutes of polymerization at 70 ° C., 124 g of polyethylene with a melting index of 1.08 and a flow rate were obtained of 44.7.

Example 15

According to Example 12, ethylene and propylene were polymerized. In this one carried out at 70 C. The reaction vessel was tested first with hydrogen to a pressure of 1.4 atmospheres, then with propylene brought to 4.9 atmospheres and finally with ethylene up to a total pressure of 14a'.ü. To 30 minutes of polymerization were 36 g of ethylene-propylene mixed polymer with a Propylcngeh.'il of 1.6 percent by weight, a melt index

of 1.11 and a flow velocity wedge of 42. <X receive.

Examples 16-23

The dragonfly 111 shows a series of polymerizations. in which ethylene in the presence of a deposited bis (cy el open tadienyl) chromium (II (catalyst polymerized at a total pressure of elwa 14 atm would:

Table 111

Hot example Tiiigcr KaIaU
salor PoU men .Ir) 0 • .alum Tempe Howl
an l \>l> - Schnifl / -
iiulc \ ITielV
gcsclivvin aiii H. 2.1 / hurry rature nierisal iliukcil 3.5 (l'l tmi; 2.1 iMin.) (μ) (ClU 1.4 90 16 medium density silica *) 5 2.1 30th 90 60 0 0 17th medium-sized silica *) 5 2.1 30th 90 70 1.64 85.5 18th medium density silica *) 5 4.2 30th 70 64 24 19th medium density silica *) 5 60 70 124 1.08 4- '. 7th 20th medium density silica *) 4th 60 80 129 0.60 27.2 21 medium density silica *) 5 60 90 109 1.67 102 ">"> Silica **) 10 30th 90 89 1 3.6 23 Silica / alumina S. 60 43 0.03 1.86

*) Mil a surface area of 25R m ^2; g and a pore diameter of 164 A **) With a surface area of 700 mm and a l'orcnd diameter of 5 (1 to 71) A

Example 24

The catalyst used was prepared by vapor deposition of (C ₅ Hy) ₂ Cr on medium-density silica with a surface area of 258 nm and a pore diameter of 164 Å in the absence of a solvent. 0.4 g of crystalline (C ₅ Hs) ₂ Ct were mixed under an argon atmosphere with 10 g of dry medium-density silica with a surface area of 258 m ² g and a pore diameter of 164 Å (dried in a stream of nitrogen at 600 C for 18 hours). The container was evacuated to a vacuum of 2 mm and shaken. This procedure was repeated about 10 times over a period of 6 hours. Then the pressure in the container was brought to atmospheric pressure with argon. The catalyst was stored for 3 days, then 0.4 g was removed and used for the polymerization of ethylene under the conditions mentioned in Example 2. After one hour, 87 g of polymerizate with a melting point of 3.9. a flow rate of 148 and a density of 0.963.

Example 25

300 g of a silica carrier with the composition shown in Table IV and those mentioned there physical properties:

Table IV

Components c

SiC) ₂

Na ₂ O

SO ₄ (water soluble)

Dry basis 0

97.95 0.05 0

Sieve size

0.250 mm 0.149 mm 0.105 mm 0.074 mm Surface area Average Pore diameter

larger than the respective sieve size

0.0 max.

4.0 max.

10.0 max.

9 33 338 no g 170 \

was dried under a nitrogen atmosphere at 650 ° C. for 12 hours, under a nitrogen blanket cooled and placed in a 3-1 glass flask. This was with cut-in standard glass cone connections and give away a sintered glass with a stopcock in the bottom Flue pipe was connected. The flask also came with a stirrer. Thermometer and electric Hcizmantel provided. Particular care was taken to ensure that only pipe at all connection points was used, which was impermeable to oxygen and water. All trigger devices were extracted by bubble traps and the fitted flask was prior to the addition of the silica carrier flushed with nitrogen

There was enough isopentane to make it added to a slurry, and 300 ecm of an isopentane solution were mti 9 g of bis-cyclopentadicnvlFchromUl) were added. To After stirring for 4 hours, the solvent was drained off through the sintered filter base. The Kolbei was heated to 40 C and a small stick was used to remove the remaining solvent amount of substance passed over the piston head, r / s was produced a free flowing, dark red powder. Tuesday drained liquid was clear as water. was however dark green on contact with air, indicating a small amount of chromium residue.

The catalyst was attached to a large vortex under a plastic deck bedtrcaktionsgefaßes with a lower Reaktorab section of 60 cm in diameter and 3.6 m in height

and an upper section 1.05 m in diameter and 1.05 m high. The fluidized resin bed in the reaction vessel had a depth of 2.1 to 3 m and was on a wire screen of 0.25 mm clear mesh size made of stainless steel, which in turn was heard from slavery. The reaction vessel was filled with clean, finely divided Polyethylene has been prepared for use. Moisture and oxygen were through again Circulating nitrogen or ethylene at 80 to 90 ° C has been removed. The bed continued to grow conditioned by swirling small polyethylene with nitrogen at 80 to 100 "C, whereby sufficient Triethyl aluminum to react with all moisture and others possibly remaining trace toxins was added. The nitrogen was then vented and added to the ethylene charge and then started to feed the catalyst to the side of the bed, whereby the reaction was initiated (pressure about 8.4 atü, temperature about 90 C). The catalyst showed one Productivity of 500 kg of polyethylene per kg of catalyst.

Example 26

A deposited bis (cyclopcntadienyl) chromium (II) catalyst with 12 mg bis (cyclopcntadicnyl) chromium (II) per gram of support was among the im Example 25 prepared conditions described. This was described in Example 25 Reactor used under the following working conditions:

C)

90

Flow ratio.

Distribution: the particle size

(1.84 mm

<0.X4.
<. 0.42.
<0.25.

<0.15.
«; 0.11.

-0.42 mm
-0.25 mm.

> 0.15 mm
• 0.11 mm

.- 0.07 mm.

-. 0.07 mm

10.0

2 ~>

18.4

36.2

29.1

6.9

3.7

1.5

Examples 27 to 29

The catalyst described in Example 26 was placed in a jacketed reaction vessel at a ratio of from diameter to height of ctv.a 1: 7.5 and a top section with a diameter / height ratio of about 1: 2 is used At different hydrogen concentrations as Cjasmass flow rates between 3 and 4 G-f 3 experiments were carried out.

The exact working conditions and characteristics the Äthylenhomopolymerisatc produced are given in Table V.

35

Reaction temperature (
Rcaktionsdruck (atü). .
Ethylene in Bcschickun

(Percent by volume) 91

Hydrogen in charge

(Volume percentage) 9

The polymer produced had the following properties:

Schmclzindcx (dg min) 0.34

Flow rate 37.5

Table V

Product features
Melt index
Flow velocity wedge
Flow ratio
density

Stiffness (kg / cm ² )
Impact strength

Average
Reaction vessel conditions

Temple atur ('C)
Pressure (kg / cm ² )
Switch off water
(Volume percentage)
Ethylchalt
(Volume percentage)

example

1.2

138

115

0.95

9940

8.4
17th

2.9

250

86

0.95

9800

90

8.4
18th

82

6.5

486

78

0.95

10640

13th

100
8.4

79

The product of Example 29 was then screened using the results shown in Table VI subject.

Table Vl

■ Ό of the product

> 0.84 mm 0.35

<0.84. > 0.42 mm 1.67

<0.42. > 0.25 mm 22.9

<0.25,> 0.15 mm 44.3

■ -.0.15; > 0.11 mm 11.6

<0, ll,> 0.07mm 9.17

<0.07 10.1

The average particle dimension was 0.155 mm.

Example 30

According to Example 5, a deposited bis (cyclopentadienyD-chromium (catalyst produced, however, as a concentrated slurry in the catalyst container of that described in Example 25 Fluidized bed reaction vessel was transferred (pressure about 8.4 atü. Temperature about 90 ° C). This catalysis sator showed productivity in its use of 1300 kg of polyethylene per kg of catalyst.

Examples 31 and 32

60 Fm of seasoned. 0.0445 g of bis-cyclopentadienyD-chromium III per gram of catalyst containing carrier was prepared as in Example 18. Two experiments were carried out in the reaction vessel described in Examples 27 to 29.

The exact working conditions and properties of the ethylene polymers produced are in Table VIl summarized:

609 641/95

25th

08 388

Table VII

26th

Product properties melt index flow velocity wedge Flow ratio density

Rigidity (kg / cm ² ) impact strength

Average reaction vessel conditions

Temperature ("C) pressure (kg / cm ² )

Hydrogen concentration (percent by volume) Ethylene concentration (Volume Percent) Productivity (g resin / g Cr)

llc example 32 31 17.0 0.84 - 44.4 33 0.961 0.956 9940 8400 49 90-95 80 8.4 8.4 10 5

12500

90

148000

Example 33

A portion of that prepared for Examples 31 and 32 from 3.2. a flow rate of 162 unc

Catalyst was then in the example 1 bc- a flow ratio of 51. Polyethylene was ir

written reaction vessel is used. A 95% ratio of 1000 kg of resin per kilogram

Ethylene and 5% hydrogen containing Beschik catalyst produced. The "average part

This was then polymerized at 95 ° C. and 7 atmospheres. The size of the product was 0.34 mm.
and gave a polymer with a melt index

Comparison attempts

Table VIII

Polymerization tests with catalysts on silica or silicon dioxide *)

attempt

Catalyst components chrome
connection Reaction condition; '. ungcn CJH, Chromium compound (mg I Line temperature (al) 11th (Hourly I C) 21.0 Bisbenzene chrome 13th 0.75 90 21.0 Bisbenzene chrome 44 1.0 90 21.0 Bisbenzene chrome 5 0.50 90 14.0 Bis (cyclopentadienyl) -
chrome (II) 1.0 90

Yield of polymer

(Cl

0 0 0

• i The chromium compounds were treated with 0.4 g of silicic acid. average particle size about 70
which was at 5 (Ml to "HI C dchvdratisicrt" order. um ^ donkey / l

Explanations for Table VIII

The catalysts were prepared by adding the respective organic chromium compound to 0.4 g O ii Obfläh t 350 ² di

The catalysts were prepared after the polymerization was carried out in slurry i

the respective organic chromium compound carried out on 0.4 g of 500 ecm η-hexane.

SiO ₂ with a surface area of about 350 m ² g, the <, _ _s The polymerization was at 90 C at a

Activated at 500 to 600 C for> 18 hours. Ethylene pressure from 14.0 to 21.0 1 tu ¹ ₂ to 1 hour

was upset. The amount of organic chrome long carried out.

VIII d

was, applied g g

connections can be found in Table VIII.

27 I ^ ^f & 28

Table IX

Polymerization experiments with catalysts on silicon dioxide alumina *)

\ er Kalalvsalorkoniponenleii Polvmerisalionshedbedingungen KaIaI) - i'igeiisehaflen des l'olvmcrisais

svieh salor-

Chromium connection Chrom- H. (\ llj 11. (', 1I ₁ akliMl.ii SI ¹ I l-'Ci ² ) Vnnl-

verhin- gelialt'l

manure

Bisbenzene chrome (mg) (on I.ItI 0 ig l \ »l> - Uli! Milli I dg Mm -I 1.5 Bisbenzene chrome 0.03 merisal l.S. Bisbenzene chrome 0.11 Millirmil 1.8 Bisbenzene chrome 0.20 Cr 7.0al 1.9 Bis- (cyclopenta- 0.081 C ₂ H ₄ I. 0.05 1 dienyl) chrome (ll) 40 0 21.0 192 no FIuIJ 0.2 V 40 0.7 20.3 140 no river 1.0 3 40 2.1 18.9 144 no · river 2.1 4th 40 3.5 17.5 145 no river 2.9 5 12th 1.05 1.3 485 0.95 58

*) 0.4μ SiO, ΛΙ, Ο, (dehydration temperature WK) C): the reaction was carried out for 1 hour at 41 C.
¹ I SI = Schnielzindcv ² ) FG = flow velocity. ³ I Vinvlgruppen K) (K) Kolilenslollatoiiie.

The catalysts were prepared by taking booty from the polymers obtained are shown in Table X

the respective organic chromium compound put together to 0.4 g.

SiO ₂ Al ₂ O ₃ (SiO ₂ : Al ₂ O ₃ = 87: 13) applied. The 25 for the production of the catalyst used were

Carrier had a surface area of about 500 nr g and 15 mg (in Examples 34 to 41) and 10 mg (in

had been activated for> 18 hours at 600 ^{r C.} Examples 42 to 46) of the organochrome compound

The amount of chromium compound used can be from a solution in hexane to 0.5 g of silicon dioxide

Table IX can be found. medium density with a surface area of

The polymerization was carried out in slurry in about 300 nr g. that at 600 C for > 18 hours active

500 ecm η-hexane carried out. had been fourth. dejected.

The polymerization was carried out for 1 hour. All reactions were carried out in 500 cm ^{3 of} hexane im

Temperature of 9TC at a total pressure (Ethy-Autoclave carried out the reactions of the examples

len and hydrogen) of 14 or 21 atmospheres. 34 to 41 30 minutes under a total pressure of

. . 35 14 atü and the reactions of Examples 42 to 46

Examples 34 to 4b 60 minutes under a total pressure of 12 atmospheres.

Thirteen ethylene homopolymers were used. In some examples, hydrogen was used. at

nen carried out to ascertain the usefulness of the absence of hydrogen was the entire

a carrier located bis-methylcyclopcntadi- specified pressure generated by the ethylene. At presence

Enyl) chromium (II) to illustrate as a catalyst. 40 healing of hydrogen, as indicated in Table I.

In a number of examples the customary ethylene was used in so large quantities that the

The availability of this organochrome compound was achieved with a total pressure of 14 or 12 atmospheres.

Bis (cyclopentadienyl) chromium (II) (on a carrier) The products obtained are

compared. The reaction conditions as well as the solid polymer of high density.

Table X

Example chromium compound H _: Reaction · »Yield Sehmcl / inde

wedge
(atül

34 CpCr 0 70 96.1 NF

35 CpCr 0 70 102.2 NF

36 MeCpCr 0 70 114.1 NF

37 MeCpCr 0 70 109.9 NF

38 CpCr 2.1 70 110.1 1.67 28.0

39 CpCr 2.1 70 100.6 0.65 43.4

40 MeCpCr 2.1 70 104.9 1.07 37.6

41 MeCpCr 2.1 70 114.1 1.84 39.6

42 CpCr 1.05

43 MeCpCr 1.05

44 MeCpCr 1.05

45 MeCpCr 1.05

46 MeCpCr 1.05

CpCr - bis (cyclopcntadicnyl) -chromtll) MeCpO = bis-lmeth \ it) clopentadicr, \ ii-i.hrom (III NI No flow

Reaction·,· Au-beuK ' temperature (Cl 70 96.1 70 102.2 70 114.1 70 109.9 70 110.1 70 100.6 70 104.9 70 114.1 85 94.7 85 111.7 85 109.0 85 114.4 85 101.4 neth \ it \ v.lone ntadicmii-i'hromilli

Examples 47 and 48

8 08 388

Two ethylene homopolymerizations were carried out; to illustrate the utility of supported bis (tert-butylcyclopentadienyl) chromium (II) as a catalyst. To prepare the catalyst, 0.11 millimoles (Example 47) or 0.055 millimoles (Example 48) of the organochrome compound were precipitated from a hexane solution onto 0.4 g of activated silica. Had in Example 47 used silica carrier has a surface area of about 350 NRVG and had been activated at 800 ⁰ C (for> 18 hours), which in the example 48 used silica carrier had a surface area of about 300 NRVG and was at 6O5 ° C (for> 18 hours) must be activated.

The two reactions were each carried out in 500 cm ^{3 of} hexane in an autoclave for 1.5 hours at 85 ° C. under a total pressure of 14 atmospheres. In Example 47 the hydrogen pressure was 1.05 atmospheres and the remainder of the total pressure was provided by the ethylene. In Example 48, no hydrogen was used and the total pressure of 14 atm was generated by the ethylene.

In Example 47, 11 g of polymer and im Example 48 18 grams of polymer produced. With the received Polymers are solid, high molecular weight polymers. When examining on the melt index they showed no flow (i.e. S / = 0).

Examples 49 to 51

Three ethylene homopolymerizations were carried out to illustrate the use of magnesium oxide (MgO) and magnesium silicate (MgO — SiO ₂ ) as inorganic oxide carriers.

The carrier of Example 49 is 0.4 g of MgO with a surface area of 50 m ² / g, which had been activated at 600 ° C. (for> 18 hours), and the carrier of Example 50 is 0.4 g of MgO with a surface area of 140 m ² / g, which ^{had been activated at 600 °} C. (for> 18 hours), and the carrier of example 5 i is 0.4 g of MgO — SiO ₂ with a surface area of > 50m ² / g activated at 53OC (for> 18 hours).

To prepare the catalysts for these three examples, 20 mg of bis-tcyclopentadienyO-chromium- (II) precipitated from a hexane solution on the activated carrier.

All three polymerizations were carried out in 500 cm 'hexane in an autoclave for 30 minutes at 87 to 90 ^° C. under a total pressure of 14 atmospheres (1.05 atmospheres H ₂ and 12.95 atmospheres C ₂ H ₄ ).

The yields and melt indices of the polymers obtained are shown in Table XI.

Example carrier material

50

Dent enamel FG ** |
index*)

(g | (dg / min.) Idu min.)

2.5

6.0

2.3

146

label XI \ us he Ii lc Aclinic
index* g Mi W-
ι 1X3 ** 1 iJcample Carrier material (μι κ! 24 η.Ι (dg min 6.5 0. 13th 19th MgO
(50 m ² / g)

MgO

(140m ² / g)

51 MgO ■ SiO ₂

(> 50nr / g)
*) Melt index ASTM D-1238 measured at 190 C.

**) Flow rate according to ASTM D-1238. measured at Ten times the weight used for the Sch-ncl / jndcx.

Examples 52 and 53

Polymerizations were carried out in which butene-1 was copolymerized with ethylene.

About 4 percent by weight were used to prepare the catalysts used in the two reactions Bis-icyclopentadienylJ-chromOI) on silicon

umdioxyd with a surface area of about 300 m ² / g, which ^{had been activated at 600 0} C (for> 18 hours), precipitated. The chromium compound was deposited on the support from a hexane solution. The reaction was carried out in hexane

ζ-; 90 ° C under a total pressure of 31.5 atü in counter-

"Was carried out by hydrogen. The further reaction conditions and the yields achieved and the properties of the copolymers obtained

are summarized in Table XII.

Table XII example

52

C ₂ H ₄ , mole percent 20.0 17.1

C ₄ H ₈ , mole percent 0.75 2.7

H ₂ , mole percent 1.015 0.015

H ₂ VH _{2 +} C ₂ H ₄ , molar ratio 0.00075 0.0009

C ₄ H ₈₇ C ₄ H ₈₊ C ₂ H ₄ , 0.036 0.136
Molar ratio

Response time 4 16

Yield, kg resin / kg 2200 1100

Catalyst / hour

Density of the copolymer 0.951 0.94 «

Melt index of the copolymer 0.23 0.20

Examples 54 and 55

In one reaction, dicyclopentadiene was copolymerized with ethylene and in a control reaction Ethylene homopolymerized.

To prepare the catalyst for the two reactions, 10 mg of bis (cyclopentadienyi) chromium (II) were added to 0.4 g of silicon dioxide with a surface area of about 300 nr / g, which had been activated at 600 ° C. (for> 18 hours). dejected. The chromium compound was filled onto the carrier from a solution in hexane. The reactions were carried out for 1 hour in 500 cm ^{1 of} hexane at 85 ° C. under a total pressure of 14 aiii (1.05 atmospheres H ₂ and 12.95 atmospheres C ₂ H ₄ ).

In the copolymerization reaction the MoI was - (, s ratio of dicyclopentadiene to chromium compound 22.60.

The yields and properties of the two polymer products are summarized in Table XIII.

Table XIIl

Homopoly copolymers * meres

Yield g / g catalyst / hour
Melt index dg / min.
Flow ratio

109

4.5 47

44 2.0

71

The two polymers were also determined by IR spectroscopy Analyzes made. The copolymer showed absorptions at 10.6, 10.85 and 12.5'μ, this is characteristic of copolymers with dicyclopentadiene units (see European Polymer Journal Vol. 1, p. 121 [1965]). '*

Examples 56 to 58

Copolymerization of ethylene and vinyl norbornene. Catalyst production

Three separate catalysts were prepared by adding 20 mg of bis-icyclopentadienyU-chromUI) Table XIV
Copolymerization of ethylene and vinyl norbornene

precipitated on 0.4 g of activated silica. The silica had a surface area of about 325 nr / g and had been activated by heating at 600 C for> 4 hours. The organochrome compound was added to the silicon dioxide in the form of a solution in η-hexane.

Polymerisation reaction

One of the analyzer samples was used to homopolymerize ethylene in a control area (Example 56) and the other two catalyst samples were used to copolymerize ethylene in a control example (Example 56) and the other two catalyst samples were used to copolymerize ethylene with vinyl norbornene. All three experiments were carried out in a closed autoclave in 500 cm ^{3 of} η-hexane under suspension polymerization conditions. All reactions were carried out at about 85 ³ C for 30 minutes under a total pressure of Hatü (12.95 aiii ethylene plus 1.05 atmospheres H ₂ ).

example VNB Polymerisal
bulge SI Ki (cc ml IgI Idg'Min.i (dg min.) 56
57
58 0
0.2
0.5 116
129
116 5.2
1.08
0.43 205
101
56

1 RR

density

(g ecm)

F.Mrahierhare PoIv mere * I

39 0.955 5.2 94 0.954 5.9 56 0.951 3.5

VNB = vinyl norbornene.
KG = l-letgeselnvindigkcit (highly charged SchmclzindcM ASTM D-123X measured at ten times the Heim Schmel / -

index (Sl | weight used. 1 "RR = FG / SI.

*) = 24 hours in boiling cyclohexane.

Examples 59 to 64

Copolymerization of ethylene and methylnorbornene. Catalyst production Nanochrome compound was added to the silica in the form of a solution in η-hexane.

Polymerization reaction All six catalysts were used to < opolymeric

sation of ethylene with methylnorbornene used.

Six different catalysts were produced, with the six tests being carried out in one closed unit

placed by placing 0.016 to 0.020 g of bis- (cyclo-autoclave in 500 cm ^{1 of} η-hexane iiniei suspension

pentadienyl) chromium (II) on 0.4 g activated silicon polymerisation conditions were carried out,

Dioxide precipitated on a surface area The reactions were under a total pressure

of about 325 m ² g and by heating to 14 atü (13.44 atü ethylene plus 0.56 atü Hl cimrh-

600'C had been activated for> 4 hours. The Orne leads.

mn ii darling I Mi.ilnei

MM

IS I.

table XV temperature Xl length of time Pohnionsiil-
itusbcutc SI Ki IR K I) ιι h example MNB (Cl S'4 (Mm.I (dp Mm.) (you Mm I ■ ι · lccmt 79 76 35 113 2.47 1 If P. ■ "Μ 59 S. X2 72 30th 78.6 1.83 KKi - _χ ι. 60 10 70 S7 30th 153 4.40 ! U > I. 61 20th 69 7X 30th 149 0.9X \ I Ί \ 62 10 83 niieii.
UiCH ₁ -C
h.iies Im 10 V} J ^Ί 7.4 ι IH I 63 20th 75 10 92.4 i (i.7 ΙΙ.Ί.1 64 30th Mctlnlnmbi
Veihällnis \ ι
'Ό! », Trainer ii uppcn iOOü {. -Ahniu'M ι
Mciifiuk'm n-1 k'vin i'tn η del PoU m
. " ¹ J Sliiinlcn egg trowel
ι MNH
* l
** l

To this end, 2 bhill / .eiehniinuen

Claims (2)

Patent claims: I. Process for the polymerization of ethylene, alone or together with a minor amount at least one other -olefin and / or a smaller amount of at least one diolefin Temperatures from 30 to 200 "C and pressures from 1.4 to 56 atü in the presence of a catalyst from an organochrome compound, which is based on an inorganic oxide with a high surface area is absorbed, characterized in that the organochrome compound is bis (cyclopentadienyl) chromium (II) or its substituted derivatives with one or more substituents the cyclopentadienyl rings, which do not affect the catalytic efficiency. 2. The method according to claim 1, characterized in that the melt index of the ^ o polyethylene obtained is regulated to a predetermined value with the aid of hydrogen by carrying out the polymerization using an ethylene and hydrogen concentration calculated from the following formula: corresponding speed to the polymerization zone and f) additional monomer and catalyst imports according to consumption.