DE2053400A1 - Method for dispersing a polymerization catalyst - Google Patents

Description

PATENT LAWYERS

DR.-ING. H. FINCKE s Munich ₅ ,

DIPL.-ING.H.BOHR M ».« «T« _B. 3i ^

DIPL-ING. S. STAEGER ^ ro / nn

Fe _rnfufi -266060 2übJ4UU

Folder 224-18 - Dr, P 22297

Imperial Chemical Industries Ltd. London, UK

Process for dispersing a polymerization

catalyeators

Priority: October 30, 1969 - Great Britain

The invention relates to the polymerization of alpha-olefins including ethylene and to catalysts which are suitable for the polymerization of such olefins »

Polyolefins are widely used in the manufacture of a large number of different molded articles, as well as for the manufacture of films and fibers · One use that has been suggested for polyolefins, and particularly for polypropylene, is as an addition to a paint. For this it is necessary that the polymer is added as a fine powder. This fine powder becomes more convenient

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ORIGINAL INSPECTED

Way produced directly by polymerization using a finely dispersed polymerization catalyst.

The invention relates to a method for dispersing a polymerization catalyst, wherein a catalyst consisting of an organoaluminum compound and a solid Connection of a transition metal of lifting groups IVa to VIa of the periodic table is used to polymerize a smaller amount of an alpha-olefin in the presence of an inert polymerization diluent, ' which is a saturated or unsaturated cyclic compound from the group cyclohexane, cyclohexene, benzene, Tetralin and chlorobenzene 1st, being the alpha olefin one branched chain olefin of the formula

- f CHg J

CH

or an olefin of the formula

«OH -

, wherein η door is 1 or 2;

m is 0, 1 or 2;

for a hydrogen atom or an alkyl group stands;

and H, stand for alkyl groups; and

Βλ stands for a cycloalkyl, cycloalkenyl or aromatic ring system, which Ringeyetem with Alkyl groups can be substituted.

The transition metal compound is preferably a halogen ¹ . and especially a chloride. The transition metals, the compounds of which can be used in the process of the invention, include vanadium, zirconium and, in particular, titanium. The solid transition metal compound can be produced by one in hydrocarbons

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soluble compound of the i-metal, such as ίδ.Β. TiCl ^, and VOOl ,, using a suitable reducing agent reduced. However, this mode of operation is not absolutely necessary, since fixed reduced compounds that have been prepared in a different way, and unreduced compounds such as TiOl ,, VCl, and ZrCl ^, can be used according to the invention

The preferred transition metal compound is titanium trichloride, which includes not only pure titanium trichloride, but also those materials that are sold as "titanium trichloride ¹¹ and contain TiCl, co-crystallized with compounds of other elements, especially aluminum in the form of aluminum trichloride" The following types of titanium trichloride were used for the polymerization of olefins;

1) The product obtained by heating a mixture of steam and hydrogen, which is essentially pure titanium trichloride.

2) A product that is commercially available and called titanium trichloride and which is obtained by reducing TiCl ^ with metallic aluminum and which is actually a solid crystal composition with the approximate empirical formula or 3TiCl, -A101 *. This material can be produced by adding metallic aluminum and aluminum chloride to TiCl ₁ ^, heating the mixture under flowing-in, and then separating the mixed crystal product from the excess unreacted TiCl ^, for example by distillation at low pressure (not to mention that - To remove added TiCl ^), as described in British patent specification 877 050. Since the product obtained is somewhat coarse, it is preferred to grind the product, for example in a dry ball mill, before using it as a catalyst. One such

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However, grinding does not result in a dispersion as fine as that obtained with the process according to the invention. The mixed crystal product can alternatively also be obtained by grinding an excess of titanium tetrachloride with metallic aluminum at temperatures of up to 200 ^° C. in a ball mill.

3) A particularly preferred process for the production of Titantrichlorld is that titanium tetrachloride with Alumlniumalkylen or aluminum haloalkylenes, such as. B. Aluminiumtrlisobutyl, Dlisobutylaluminiumhydrid, Äthylaluminiumdiohlorid, Diäthylaluminiumfluorid and preferably Diäthylalumlniumchlorid, ethylaluminum sesquichloride or Isobutylaluminlumsesquiohlorid »reacted · Bas titanium tetrachloride and the organoaluminum compound at a temperature in the range of -10o to + 100 ⁰ O ⁰ C and advantageously -20 ⁰ C to +40 implemented ⁰ C, wherein the ratio of aluminum to titanium from 0.1 to 4.0 and preferably from 0.3 to 2.0 x is obtained in this catfish brownish red trivalent Titanausfällung can immediately st 1 to 5 to 60 to 120 ⁰ C. or the precipitate can be washed with an inert organic medium such as that in which the reduction of tetravalent titanium to trivalent titanium has been carried out and then dried. The precipitated titanium trichloride component can be heated more than once if necessary. Care must be taken that the operations are carried out in the absence of oxygen and moisture. The titanium trichloride component obtained in this way contains aluminum chloride and usually also an organoaluminum halide, and it can be in the form of β-TiCl, or in the form of the purple crystalline TiOl.

Di · solid tft> »rg * nc * m» * fr * 'l ^{Ί vaiy1b 1} «dung ·» are not all so easily dispersed and in general the

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the easiest way to obtain dispersing agents is that one a compound soluble in a hydrocarbon "reduced with an organoaluminum compound, as described in (3) for titanium trichloride"

It has been found that the catalyst can only be dispersed using the diluents listed. The dispersion is effected at a temperature la range from 30 to 80 ° 0; a suitable temperature is 60 ° 0.

Suitable monomers for use according to the invention are, for example, branched-chain alpha-olefins which are branched in the 4- or 5-position * Typical of such olefins are 4-methyl-pentene-1 and 5- * methyl-he3cen-1. Monomers which contain a ring system and which can be used according to the invention are, for example, allylcyclohexane and styrene. The amount of monomer used appropriately does not exceed 20 hol alpha-olef per mole of transition metal, and it has been found that satisfactory dispersions are obtained can, when 6 moles of monomer is used per mole Übergangenetall * is out !, noted that the catalyst using a mixture of? .wei or more of the alpha-olefin specified monomeric or, alternatively, using a mixture of one or more of the! specified alpha-olefin monomers together with a smaller amount of a further alpha-olefin monomer can be pearled, with as further alpha-olefin monomers

In particular the higher unbranched alpha-olefins, such as

~ -r *, _ λ <~ λ λ ._ μ - ^ can be used ·, _ e.g. pentene-1, Heaten-1, octene-1 and decene-I // ELn example

is the mixed polymerization of 4 ~ methyl * -pentene-1 with Wt. 56 decene-1.

The effectiveness of the dispersion technique depends on the combination of the diluent used and the monomer used. 4-Methyl-pentene-1 gives an effective one

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Dispersion in cyclohexane or cyclohexene as a diluent, while better dispersions are obtained with styrene when using benzene as a diluent. " Indeed, it was found that although the catalyst with the specified monomers and diluents, not all combinations of monomers can be dispersed and diluents are effective. Thus, using styrene, a dispersion is made with both chlorobenaol and Get tetralin; on the other hand, with 4-methyl-pentene ~ 1 there is none Dispersion obtained when using these diluents? turns.

According to the invention dispersed catalysts can one or more olefins (including ethylene) under low temperature conditions are used and a low pressure typical of Ziegler polymerizations to polymerize to obtain a polyalpha-olefin with a small particle size will. Alternatively, dispersed catalysts can be pumped according to the invention and are suitable for the Use of polymerizations carried out under conditions of high pressure and high temperature as are, for example, typical of those conditions which are necessary for the printing polymerization of ethylene be used·

Thus ethylene can be polymerized at a temperature of not less than 125 ° C. and a pressure of not less than 500 at, typically 140 to 30O ⁰ C and 1000 to 3000 at, using a dispersed catalyst according to the invention. The ethylene is preferably polymerized using conditions of temperature and pressure such that the polymerization reaction mixture forms a single liquid phase and remains in a liquid phase until it has been discharged from the reaction zone or until the polymerization has ended a single liquid phase

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it is preferred "at a temperature in the range of 160 to 260 ° 0 and under a pressure of at least -1400 at to work. The Ziegler catalyst is highly active under this high pressure and temperature, and θs is possible to convert at equilibrium of 40,000 or more moles of ethylene, the ^ mole of transition metal compound polymerized, especially when titanium trichloride is used. At such conversion values, the finished polymer contains less than 500 ppm by weight total catalyst (equivalent to about 50 ppm titanium), so there is no need to treat the polymer to remove this residue.

When using these catalysts under typical low pressure conditions, ie at a pressure up to approximately 20 atm and at a temperature in the range from 20 to 100 ^c C, the polymer is obtained in a fine particle form. However, under these conditions it is necessary to remove the catalyst residues from Separate polymer, since the conversion obtained is not as high as in the high pressure polymerisation of ethylene.

In any type of polymerization in which the finely dispersed Catalyst of the invention used can include chain transfer agents be used. These will usually also be required to determine the molecular weight of the Product decrease. A suitable chain transfer agent is hydrogen.

Many variations of the catalyst dispersion technique are possible within the scope of the invention and the following examples illustrate the dispersion of the catalyst according to the invention and the use of the dispersed catalyst for the polymerization of olefins under different conditions.

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Examples 1 to ^

of the catalyst

Eijie series of experiments was carried out on a catalyst to disperse on the Baals of titanium trichloride

Has titanium trichloride was produced by reacting TiCl ^ and ethylaluminum sesquichloride in a purified hydrocarbon fraction, which consisted of a mixture of branched, saturated aliphatic hydrocarbons with a boiling point in the range from 170 to 190 ^° C. (it is referred to in the following as "diluent A" ) · a solution of the Sesquichlorids in diluent a was gradually tropfenväse with stirring to a solution of ^ ΤΙΟΙ in diluent a for a period of several hours added, the temperature was maintained at 0 ⁰ C. The molar mass of the total aluminum to titanium was approximately 1.6. The resulting slurry, containing the TiCl, was then heated to 95 ° C for a period of time. The TiCl3 was then washed several times with fresh amounts of Diluent A.

10 millimoles of diethylaluminum chloride and 5 millimoles of titanium trichloride were introduced into a 300 ml stirred container under nitrogen, so that a total volume of 1? »4 ml of catalyst suspension in diluent A was obtained. A further 40 ml of diluent and 30 millimoles of monomer were added to this catalyst suspension. The details of the treatment and the results obtained are shown in Table 1, in which the comparative examples are identified by letters. All experiments were performed at 60 ⁰ C.

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- 9 - table

example
ι or
! Comparison
example

Monomer

Separate thinner effect

styrene

k ~ methyl ~ peaten-1

Diluent A

Cyclohexane

y penten-1

4-methylpentene-1

Cyclohoxane

Cyclohexene

4-methyl-pentene-1

5-methylhexene-1

Benaol

Cyclohexene

^r >

Dtjrrol

benzene

4-methyl-hexane ] penten-1 Large lumps of polymer ~ no dispersion

Slurry thickens in 7 minutes. Good dispersion. No particles with more than 2 K.

No dispersion. A part-chan-shaped one forms Polymer.

The particles do not exceed 2 M and are embedded in galerte lumps. No overnight breakup.

Gelatinous slurry easy to disperse. No catalyst sites Bigger than 2 M-.

Catalyst on 'i to 5 ^ » mostly 1 / ί in 10 min dispersed. In loose agglomerates connected by the jelly - no sitting down during the weekend *

Mainly particles with 1 / t, which lead to agglomeration tend into loose lumps! The dispersion improved over Efach.

No dispersion. Particulate polymer formed.

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Example 6 Polymerization of

30 millimoles of diethylaluminum chloride and 15 millimoles of titanium trichloride (prepared as in Examples 1 to 5) and 120 ml of air-free, dry cyclohexane were introduced under nitrogen into a 300 ml stirred container: the container and its contents were ^{heated to 60 °} C., and 90 millimoles 4-methyl-pentene-1 were introduced. The color deepened from purple to magenta and the slurry thickened within 3 minutes. A microscopic one. Examination showed that the Ka täLyeat place eilchen which initially had a diameter of 25 / ·, were dispersed in very loose agglomerates of about 40 A diameter, wherein the agglomerates containing a number of catalyst distributed with a diameter of 1 A continuous.

A sample of the treated catalyst containing 5 millimoles of TiClx was used to polymerize propylene 1 at pressure and 60 ° C in 1 1 of diluent A used. After 1 1/2 hours after 26 g of propylene have been polymerized the experiment was terminated with 20 ml of isopropanol and the slurry was washed twice with water *

The polymer obtained consisted of very elongated small cords with a diameter of about 40% which were dispersed in the hydrocarbon solvent and showed only a slight tendency to settle overnight. The polymer could be dried by evaporation to give a white powder was obtained, which in turn in a suitable diluent, for example in xylene _t, could be dispersed by maceration.

The procedure described was repeated using a catalyst similar to that not for dispersion had been pretreated. The polymer slurry sat down within seconds of finishing the

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OADOIItQiNAL

Stirring, and the polymer particles had diameters from 100 to 150 / *. Maceration of the dried powder in xylene gave virtually no dispersion of the powder.

Example 7 *

Polymerization of ethylene at high pressure.

Ethylene was polymerized in a continuously stirred autoclave reactor at a temperature of 200 ° 0 and a pressure of 2000 at. The catalyst used was using 4 ~ methyl-pentene dispersed in Oyclohexan ~ 1 £ been wherein the 4-methyl-pentene-1 in an amount of 6 moles of 4 ~ methyl <~ penten-1 ^ e moles of titanium trichloride used in the catalyst had been. The procedure was the same as in Example 5 * More diethylaluminum chloride was added to the dispersed catalyst so that a final ratio of diethylaluminum chloride to titanium oxide of 4: 1 resulted. The dispersed catalyst was diluted with isooctane so that a titanium concentration of 0.003 mol / l was obtained. The average residence time of the ethylene in the reactor was 90 seconds, and the diluted catalyst was introduced directly into the reactor so that a catalyst concentration in the gas of 1.6 mol-ppm was obtained o 9% of the ethylene was polymerized and the yield of polyethylene was 57,000 moles of polymerized ethylene per mole of titanium trichloride.

The polyethylene obtained had the following properties:

Melt flow index 3.3

Stress exponent "1.25 density 0.964 g / cBL ⁵ .

The melt flow index of the polymer was measured by ASTM method Verveadung 1238-62T, using a 2.16 kg weight was used at 190 ⁰ C.

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* ^ BATH

The spajo fixation exponent is defined by the following ratio:

Stress exponent - log ATIg - los SFI _{2 f16}

log 5 - log 2.16

: _c and SFI ₃ j, c are the melt flow indices measured using a weight of 5 kg and 2.16 kg, respectively, at a temperature of 190 ° G.

The density was measured using a density gradient column, and a compact, the previously st 1 at 100 ⁰ C was annealed.

The stress exponent is an indication of the molecular weight distribution: a low stress exponent indicates a narrow molecular weight distribution "A stress exponate of 1.25 is a measure of a narrow molecular weight distribution.

Example 8

The technical dispersion given in Examples 1 to 5 was repeated, the titanium trichloride component used being a material which had been prepared by reducing titanium tetrachloride with aluminum and which is commercially available as Stauffer AA and Toho TAG 131 titanium trichloride. The additional diluent consisted of 40 ml of cyclohexane. A sample of the dispersion was taken 13 minutes after the addition of 30 millimoles of 4-methyl-pentene-1 monomer, and it showed that the dispersion of the catalyst was incomplete because some particles had 40% in addition to the dispersed material with less than 5% / t diameter were available. A further 37 ml of cyclohexane, 15 millimoles of 4-methyl-pentene-1 and also 10.5 millimoles of decene-1 were then added to the dispersion. 18 min after this addition, a sample was taken, which showed that all particles were reduced to less ale 5 ^ diameter, with the majority having about 1 M; they were in one

viscous medium dispersed .. - _yo - _n «

^{/ Z1OÜ} BAD

Example 9

The procedure and catalyst were as in the examples 1 "to 5 is described" The additional dilution ~ medium consisted of 40 ml of cyclohexane, and the monomer was a mixture of 25.5 millimoles of 4-methyl-pentene-1 and 4.5 Millimoles decene-1. Hach 20min showed a sample of something viscous slurry indicates the presence of very few particles 5 A in diameter. Most of the catalyst was divided to a size below the resolving power an optical microscope (0.5 / ^ limit value).

Examples 10 to 14

A conical 100 al flask kept at 60 ° 0 and which was equipped with a magnetic stirrer was purged with nitrogen. In the flask were 10 millimoles of diethyl aluminum chloride, 40 ml of dilution medium, 5 millimoles of catalyst and finally 50 millimoles of monomer introduced. The details of the diluent, the catalyst and the monomer are listed in Table 2. Samples of the slurries were given as indicated Times taken and checked under a microscope.

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~ 14 table

example or comparative example

[analyzer

Monomer (s)

separate

thinning

aittel Time (st)

effect

10 11

12th

13th

14th

TiCl,

VCl ₁

VCl.

VCl,

VOl,

VCl,

VCl,

(β;

Allylcyclo-pyclohex & n hezan

4-methylpentene-1

4-methylpentene-1

4-methylpentene-1

4-methylpentene-1

(C)

4-methyl-

penten-1

+ Decene-1

JLllylcyclo-pyclohexane hexane

Cyclohexane

thinning aittel A (b)

Cyclohexane

Finishing agent A

Cyclohexane

V2 12th

12th

12th

12th

1/2

V2

well diapered to 2 ^ goss

Main part of the particles crushed to 2-5 #

Main part of the particles 20-80 & by ».

Main part of the particles 2 /% some 5 / c

Some < 2cU but most of them> 5. ^

good dispersion, all ■ < 2 Ai.

good dispersion, somewhat gelatinous. Venous particles with 10 / i

(a) Catalyst prepared as in Example 1

(b) as in example 1

(c) 20 mole% Becen + 80 mole% 4-ethyl-pentene-1

The VCl ^ in Example 11 and in Comparative Example D. was added as a solution, but was reduced by diethylaluminum chloride in solid VCl.

Examples 15 and 16

The catalyst dispersion technique was the same as in Examples 1 to 5 * except that different diluents were used. The results obtained

are given in Table 3 below.

Tabel?

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■ —j r

Monomer! Separate time

! Thinner

example

effect

15th

Styrene chlorobenzene

16 styrene tetralin 16 st ^ .2 / t parts dispersed in polymer jelly at 20 ° 0. Dispersion at 60 ° 0 improved.

2 / C particles in polymer curd at 20 ⁰ C, improved at 60 ° 0th

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Claims (1)

- * ί6 claims 1. Method of dispersing a PolymerisationskatÄ-lyeator * which consists of an Organoaluninluavcrbl nrhmg and a solid compound of a transition metal of subgroups IVa to VIa of the periodic table, characterized in that the catalyst is used to add a smaller amount of an alpha-olefin in the presence einel / poly-Merisationsrerdfinnungsaittels% n polymerize, which is a saturated or unsaturated cyclieche compound from the group Cyolohexan, cyclohexene, benzene,! is tetralin, and chlorobenzene, wherein the alpha-olefin is a branched olefin of the formula 2 or an olefin of the form wherein η is 1 or 2; β for 0, 1 or 2 stsht; &, for a vase substance atom or an alkyl group; Bg and R * represent alkyl groups; and R ^ stands for a cycloalkyl, Qycloalkenyl- or aromatic ring system, which ring-8jstem can be substituted by alkyl groups * 2. The method according to claim 1, characterized in that that the transition metal compound is a halide, preferably a chloride, of vanadium, zirconium or preferably Is titanium and that it preferably consists of titanium trichloride. Causes 3 * The method of claim 1 or 2, characterized in that the dispersion at 30 bit 80 ⁰ C will. M-. Method necb ϊΐτίβιο ö.ev claims 1 to o, characterized t, d- ^ ß as alphe-Olßfin ^ -Metb.Tl-penten-'f, 109819/2100 QAO ORIGINAL 5-methyl-hexen-1, allylcyclohexane or styrene are used will. 5 "Method according to claim 4, characterized" that polymerizes a mixture of two or more of the alpha olefins will. 6. The method according to claim 4, characterized in that «that a mixture of one or more alpha-olefins together with a minor amount of a straight-chain alpha-olefin is polymerized. 7. The method according to any one of claims 4 to 6, characterized in «the up to 20 moles of olefin per mole of transition metal are polymerized, 8. Use of the polymerization catalyst prepared according to one of claims 1 to 7 for the preparation of a polyolefin having a small particle size, an olefin monomer being polymerized under low temperature and under low pressure "which are typical for Ziegler polymerisation" ₀ 9 * Use according to claim 8 «characterized * that Ethylene is polymerized at a temperature not less than 125 ° C and a pressure not less than 500 at. 109819/2100 ORIGINAL .NSPECTH)