DE1520837C3 - Process for the production of crystalline polyolefins - Google Patents

Description

tor contains to lead to polymers of high crystallinity reach.

Furthermore, a catalyst is described which consists of a mixture of metallic sodium, the Compound 3TiCIs-AlCU and tetrakis (dimethylamino) silane and optionally an organic zinc compound (cf. laid out documents of the Belgian patent 6 28 547). The polymer yields achieved with the aid of this catalyst are right small amount.

The present invention relates to a new catalyst composition, which has the advantage of delivering more crystalline poly-oc-olefins. Other particular properties of this composition consist in increasing the rate of polymerization increase or, in certain cases, supply polymers with different viscosities and also modify the other properties as indicated above. The catalyst composition of the invention is characterized in that it contains an aminosilane compound in addition to the elements of a Ziegler catalyst has, the definition of which is given below.

The invention relates to a process for the polymerization of alpha-olefins at temperatures from 0 to 200 ⁰ C and pressures of 1 to 30 kg / cm ² in the presence of AlCl ₃ or TiCb TiCb containing an aminosilane compound of the formula

in which η is an integer from 1 to 4, R represents a hydrogen atom, a methyl or ethyl radical and R 'represents a methyl, phenyl, butoxy or phenoxy radical or a halogen atom and a reducing agent which is characterized in that trialkylaluminum, alkylaluminum hydrides or alkylaluminum halides with lower alkyl radicals are used as reducing agents and that the aminosilane compound is used in a molar ratio to the titanium compound between 0.02 and 1.5 and in a molar ratio to the organoaluminum compound between 0.01 and 0.8 .

The organoaluminum compound is absolutely necessary in the composition according to the invention. In their absence, the polymerization cannot take place, and that used in the present invention Additive is used in particular to reduce the specificity of the catalyst composition in the crystalline Area to get.

The additive or auxiliary used according to the invention has the following formula

in which η is an integer from 1 to 4. R denotes a hydrogen atom or a methyl or ethyl radical. R 'represents a methyl, phenyl, butoxy or phenoxy radical or a halogen atom.

The following are various aminosilanes as examples reproduced according to the invention as additives or auxiliaries of the Ziegler catalyst can be used.

Quater-dimethylamino-silane

Si [N (CH ₃ ) ₂ ] 4
Methyl-tris-dimethylamino-silane

CH ₃ Si [N (CH 3) 2] 3
Dimethyl-bis-dimethylamino-silane

(CH ₃ ) ₂ Si [N (CH ₃ ) ₂ ] ₂

Trimethyl-dimethylamino-silane

(CH ₃ ) ₃ SiN (CH ₃ ) ₂
Fluoro-tris-dimethylamino-silane

FSi [N (CH ₃ ) ₂ ] ₃
Dichloro-bis-dimethylamino-silane

Cl ₂ Si [N (CH ₃ ) I ₂
tert-butoxy-triamino-silane

tert. C ₄ H ₉ OSi (NH ₂ ) ₃
Phenoxy-tris-dimethylamino-silane
C ₆ H ₅ OSi [N (CH ₃ ) ₂ ] ₃

Quater-ethylamino-silane

Si (NHC ₂ Hs) ₄

The aminosilane composite component can be added to the transition metal compound prior to addition be added to the organometallic compound or to the metal alkyl before the transition metal compound is added or after the two components of the Ziegler catalyst have been brought into contact before or after the start of the polymerization.

The results are analogous for these different procedures: the crystallinity of the polymers obtained is increased in all cases, while the rate of polymerization is sometimes different. . ""'

The additive according to the invention is used in the following molar ratios:

-,. "Admixtures. _

0.02 <-j ^ r Tr <1.5

Transition metal

_{ΛΛ <} Additive _Λο

0.01 <<0.8

Metal alkyl

The application of smaller amounts does not cause any noticeable change in the properties of the without Additive used catalyst system stands out, while larger amounts lead to a considerable Reduction of the polymerization rate leads to

ren.

However, it is generally preferred to use an additive to metal alkyl ratio between about 0.05 and 0.5. The optimal range will depend somewhat on the catalyst system and the one used Additive from.

The conditions of temperature, pressure and solvent can be varied and are the same that can be used with Ziegler catalysts without additives, as stated above,

so that is between 0 and 200 ^° C., preferably 20 to 120 ^° C., and between 1 and 30 kg / cm ² , preferably 1 to 10 kg / cm ² .

Particularly important implementation conditions are given in the examples, but it is possible to use the Aminosilanes under various conditions of catalysts, temperature and pressure with different α-olefins to be used. Your effect always consists in increasing the stereospecificity of the polymerization, the generation of more crystalline ones Polymers and additionally in increasing or decreasing the rate of polymerization and the viscosity of the polymers.

With regard to the state of the art, the use of the aminosilanes as additives or auxiliaries is beneficial according to the invention in certain cases with advantages in the production costs, since the aminosilanes, starting from industrial products, can be manufactured in a simple manner. Their cost price is

thus mostly below that of the previously used additives, In addition, with the help of the Aminosilanes according to the invention superior yields with the same stereospecific effect, compared with already known additives or an improved stereospecificity with the same yield, compared to other known additives. In any case, the use of the Aminosilanes have no disadvantage, neither in terms of preservation nor in terms of the possible uses, which the end products may have, since their hydrolysis occurs rapidly and the residue denotes they can leave behind in the polymers, are neither toxic nor corrosive.

In the examples is the percentage of insolubles after extraction with boiling heptane as this is a criterion of crystallinity and thus of the stereospecificity of the polymerization. To clearly emphasize the effect of the addition of aminosilane, the values for the in boiling Heptane-insoluble substances given for the same catalyst without addition.

The values shown in the following examples with regard to the fractions insoluble in boiling heptane do not represent an absolute characteristic, since they _{depend on the TiCl 3} sample used, its preparation and activation, but the use of an aminosilane in suitable amounts always provides an increase in the in insoluble fraction of boiling heptane. In the various examples below, the values obtained without additives and those with additives for an identical TiCb are given.

The inherent viscosity or intrinsic viscosity of the polymers listed in the examples are expressed in dl / g.

example 1

Polymerizing propylene 5 hours at 6O ⁰ C and atmospheric pressure with stirring in a medium of the following composition in the order of introduction:

a) Heptane 1 1

b) dimethyl-bis-dimethylamino-silane
(CH3) 2 Si [N (CH ₃₎ 2] 2 3 mmol

c) triethylaluminum 5 mmol

d) TiCl ₃ 2 mmol

192 g of polypropylene are formed, of which 173 g are formed Extraction with boiling heptane are insoluble (i.e. 90%). The intrinsic viscosity is 6.1.

When polymerizing under the same conditions with the same catalyst components, but below If the addition of substance b) is omitted, 146 g of polypropylene are obtained, of which only 109 g (i.e. 75%) in boiling Heptane are insoluble. The intrinsic viscosity is 5.6.

Similar results are obtained if, instead of the substance used under b), the additive is used Phenyl-methyl-bis-dimethylamino-silane or diphenyl- (, ο bis-methylamino-silane used.

Examples 2, 3 and 4

When carrying out the process as in Example 1, but using different amounts of Dimethyl-bis-dimethylamino-silane were used in the The results given in the following table were obtained, in which the results of Example 1 are mentioned.

example mmol Polymers Heptane Additives weight Insoluble Comparison 0 146 75% attempt A 2 0.5 169 83% 3 1 186 86% 4th 2 197 88.5% 1 3 192 90%

If these polymerizations are carried out at a temperature of 80 ° C., increased polymerizations are obtained Rates of polymerization, however, the percentage of heptane insolubles remains very high.

It is found that the use of the aminosilane increases that obtained without the aminosilane Polymer weight causes by more than 30%, while the stereospecificity is considerable is increased. These results are particularly better than those obtained with the aid of an additive such as Hexamethyl phosphoramide or tetramethyl methylenediamine, were obtained. With one or the other of these compounds in the ratio of 0.5 mMpJ or less while maintaining the other conditions, there is also no increase in stereospecificity, however, the weight of the polymer obtained is around 10 to 20% based on the weight of the polymer obtained without the use of such an additive degraded.

Example 5

Propylene is polymerized for one hour with stirring at 70 ° C under a (relative) pressure of 5 kg / cm ² in an environment with the following composition:

a) Mixture of saturated aliphatic
Hydrocarbons with 8 to 12 carbon atoms 1 1

b) Quater-dimethylamino-silane
Si [N (CH ₃ ) ₂ ] 4 0.8 mmol

c) triethylaluminum 6 mmol

d) TiCl ₃ (activated) 2 mmol

This TiCl ₃ contains AlCl ₃ .

192 g of polypropylene were formed, 170 g of which were insoluble after extraction with boiling heptane. namely 88%. The intrinsic viscosity is 5.3. The use of triisobutyl aluminum instead of triethylaluminum leads to a similar result.

Under the same polymerization conditions, but omitting the addition of substance b) 201 g of polypropylene were obtained, 74% of which are insoluble in heptane.

Example 6

By polymerizing liquid propylene at 40 ^° C. without a solvent under a pressure of 18 kg / cm ² , with the same catalyst composition as in Example 5, highly crystalline polypropylene is obtained at a high rate of polymerization.

Example 7

The procedure is as in Example 5, but α-butene is polymerized. The polybutene obtained is greatly increased Crystallinity after molding and heating. The mechanical

see properties, tensile strength and elongation, are both excellent.

Example 8

Propylene is polymerized under the same conditions as in Example 1 and methyl-tris-dimethylamino-siian CH ₃ Si [N (CH ₃ ) ₂ ] _{3 is} used as substance b) in an amount of 1 mmol. In 5 hours at 60 ⁰ C, 122 g of polypropylene form, of which 111 g are insoluble in boiling heptane (ie 91%). The intrinsic viscosity is 7.2.

When using phenyl-triamino-silane as a substance b) a polymer with greatly increased crystallinity is also obtained, but the viscosity is lower.

Example 9

4-Methyl-1-pentene is polymerized at 50 ^° C. in an environment with the following composition:

a) Toluene or cyclohexane 1 1

b) monochloro-tris-dimethylamino-silane
ClSi [N (CHa) ₂ J ₃ 1 mmol

c) Monochloro diethyl aluminum 8 mmol

d) TiCl ₃ 6 mmol

e) Monomer 0.5 1

250 g of highly crystalline polymer with an elevated melting point are obtained. *

By polymerization at 70 to 90 ⁰ C under reflux, the resulting polymer is as crystalline as the previous one.

Example 10

It polymerizes propylene for 5 hours at 60 ° C and Atmospheric pressure with stirring in a medium with the following composition:

a) heptane 11

b) Quater-dimethylamino-silane
Si [N (CH ₃ ) ₂ ] 4 1 mmol

c) Monochloro diethyl aluminum 6 mmol

d) TiCl ₃ 6 mmol

10

15th

20th

25th

30th

35

40

94 g of polypropylene forms, 89 g of which is insoluble in heptane (i.e. 95%). If you are under Omission of the aminosilane polymerizes, only 91% insolubles are obtained.

If chlorotris- (dimethylamino) -silane ClSi [N (CH ₃ ) ₂ ] ₃ or fluorotris- (dimethylamino) -silane is used as the aminosilane compound, a greatly increased content of highly crystalline polymer is also obtained.

Example 11

Propylene is polymerized under the conditions of Example 10 and every 30 minutes without it Interruption of the polymerization 1 1 ethylene in the reaction vessel. A non-statistical one is formed Copolymer, which, however, has the consequences of polypropylene and copolymer. 102 g of polymer are obtained, 92 g of which is insoluble in heptane (i.e. 90%). However, if one polymerizes leaving out the aminosilane, only 85% insolubles are obtained.

Example 12

The α-butene is polymerized according to the procedure of Example 11. A copolymer is formed with the Follow butene-ethylene, which is soluble in heptane. After cleaning and drying, the polymer obtained has a high crystallinity.

Example 13

4-Methyl-1-pentene is polymerized according to the procedure of Example 9 using the polymerization medium holds with vigorous stirring and during the polymerization every 30 minutes 0.51 gaseous Introduces ethylene into the reaction vessel. A still crystalline copolymer is formed in the solid state.

Example 14

Propylene is polymerized at 50 ^° C. and atmospheric pressure with stirring in a medium with the following composition:

a) Hexane 1 1

b) Quater-dimethylamino-silane 1 mmol

c) Monofluorodiethylaluminum 5 mmol

d) TiCl ₃ 5 mmol ""'

91 g of polypropylene are formed, of which 82 g, which are insoluble in boiling heptane, are strongly crystalline Polymer are formed. By using monobromo diethylaluminum instead of monofluorodiethylaluminum analogous results are obtained.

Example 15

Propylene is polymerized for 5 hours at 50 ^° C. and atmospheric pressure with stirring in a medium which has the following components in the order in which they are introduced:

a) Hexane 1 1

b) dichloroethylaluminum 8 mmol

c) TiCl ₃ 8 mmol

d) Quater-dimethylamino-silane 4 mmol

51 g of polymer are formed, 47 g of which are insoluble in heptane, while in the absence of aminosilane less than 5 g of polymer is formed, most of which is soluble in heptane.

If you have methyl tris (dimethylamino) silane, dimethyl bis (ethylamino) silane, Chloro-tris- (dimethylamino) -silane, tert-butoxy-tris- (methylamino) -silane, phenoxy-tris-dimethylamino) -silane instead of

When using quater- (dimethylamino) -silane, comparable results are obtained: Significantly increased activity and significantly increased crystallinity of the polymer.

Examples 16, 17 and 18

The procedure is as in Example 15, except that ethylaluminum sesquichloride and difluoroethylaluminum are used as compound b) or dibromoethylaluminum. In each case, large amounts of highly crystalline polymer are obtained Amounts.

709 586/8

Claims (1)

10 Claim: Process for the polymerization of -olefins at temperatures from 0 to 200 ° C. and pressures from 1 to 30 kg / cm ² in the presence of TiCb or a TiCb containing AlCl3, an aminosilane compound of the formula R ' ₄ - "Si (NR ₂ ) _n , in which η is an integer from 1 to 4, R represents a hydrogen atom, a methyl or ethyl radical and R 'represents a methyl, phenyl, butoxy or phenoxy radical or a halogen atom and a reducing agent, characterized in that the reducing agent Trialkylaluminum, alkylaluminum hydrides or alkylaluminum halides with lower alkyl radicals are used and that the aminosilane compound is used in a molar ratio to the titanium compound between 0.02 and 1.5 and in a molar ratio to the organoaluminum compound between 0.01 and 0.8. 25th It is known that it is possible to stereoregulate α-olefins to polymerize crystalline polymers with various catalyst systems. The most effective of these Systems have a solid divided component that contains TiCb and a second component of the Type metal alkyl, such as. B. triethylaluminum, diethylnonochloraluminum, Diethyl monobromo aluminum, ethyl dichloro aluminum, etc. The polymerization medium is generally a hydrocarbon in the liquid state. It is also known to improve Results can be obtained by including in the composition of the catalyst substances which are a Change in the rate of polymerization, the degree of polymerization of the polymer or even the Cause crystallinity of the polymer. One can also look at the molecular weight distribution the distribution of the crystallinity of the macromolecules and, in the same way, the constants of the copolymerization act. In particular, the improvement of the stereo specificity represents a considerable technical and economic Of interest. The more crystalline the polymer, the more its properties are improved, in particular its rigidity and its heat resistance. Use as a plastic film or as a textile fiber usually requires polymers that have an increased crystallinity, and under these conditions the The polymer fraction with low crystallinity is of very poor quality and is practically unusable. Every Increasing the stereospecificity, even in proportions that initially appear relatively minor, delivers than The result is an improvement in the quality of the final product obtained and a reduction in the amount of little crystalline polymer, which in fact is often unusable. It is known that Ziegler catalysts enable the polymerization of olefins, in particular of α-olefins, at low temperatures and pressures, to thereby form resinous polyolefins. A Ziegler catalyst is a catalyst system that is created by combining an organometallic compound or of a hydride in which the metal belongs to groups Ia, Ib, Ha, Hb, IHa and IHb of the periodic Systems of the Elements, reproduced in the Handbook of Chemistry and Physics, Chemical Rubber Publishing Company, with a Group IVb, Vb, or VIb metal halide of the Periodic System is formed. Suitable metal halides that are used in the composition of a Ziegler catalyst, are chlorides and bromides of titanium, zirconium, vanadium, chromium, molybdenum and tungsten, preferably Titanium and vanadium trichlorides and tetrachlorides. Particularly suitable organometallic compounds are alkyl and especially lower alkyl compounds of the metals of groups Ia, Ib, Ha, Hb, HIa and IHb of the periodic table, such as B. aluminum, zinc, cadmium, beryllium and lithium. The organometallic compounds and the halogen compounds, such as dialkyl aluminum chlorides, are equally suitable. Examples of suitable organometallic compounds that are used to form the Ziegler catalysts, are dialkylcadmium compounds such as diethylcadmium, dimethylcadmium and diisobutylcadmium; Dialkyl zinc compounds, such as B. diethyl zinc and dibutyl zinc; the alkyl aluminum compounds, e.g. B. Diiso- ' butyl aluminum hydride, triethyl aluminum, trir sobutyl aluminum and diethyl aluminum chloride and the butyl lithium compounds and diethylberyllium and the aryl metal compounds, such as. B. Diphenylcadmium, Dinaphthyl zinc and phenyllithium. The Ziegler catalyst is conveniently obtained by using the organometallic compound the metal halide in the presence of a hydrocarbon solvent, such as. B. isooctane, n-heptane or Benzene. The molar ratio between the organometallic compound and the metal halide can vary within wide limits. A ratio of about 0.25 to about 4 moles of halogen compound, such as Titanium or vanadium trichloride per mole of organometallic compound can be useful. A typical one Catalyst system can consist of triisobutyl aluminum and titanium trichloride in equimolar proportions put together in combination. The polymerization of an "olefin is usually carried out with a Ziegler-catalyst by _(the olefin with the catalyst in the presence of an inert solvent such as. For example, isooctane, n-hexane, pentane or cyclohexane, brought into contact. The reaction is generally performed at a temperature of about 0 to 200 ° C, preferably carried out at 40 · to 15O ⁰ C, at pressures around atmospheric pressure, and preferably slightly elevated pressure. The Ziegler catalysts are not only suitable for the polymerization of ethylene, but also for Formation of resinous polymers from higher α-oils, starting from propylene and mainly α-butene, α-pentene, α-hexene, 4-methyl-1-pentene, vinylcyclohexane and including styrene. There are known catalysts for the polymerization of ethylene, which are made from compounds of heavy metals of groups IVa to VIa of the Periodic Table of the Elements, which are replaced by alkali metals, alkali metal hydrides or their complex compounds with aluminum hydride or certain boron compounds were reduced (see. German Patent 12 26 306). There is no indication in this publication that that a catalyst for the polymerization of "olefins advantageously also has a stereoregula-