DE1445365C - Process for polymerizing isoprene - Google Patents

Description

The invention relates to a method for polymerizing isoprene into polyisoprenes with high Proportion of cis-l.-J-Polymerem, which due to a low gel content and a significantly higher molecular weight, excellent properties to have.

There is already a process for polymerizing isoprene to polyisoprene with practically exclusive cis-1,4 structure (i.e. in which at least 90% of the isoprene units are cis-1,4-linked) below Use of a titanium tetrahalide-aluminum trialkyl catalyst known. Such a catalyst works very well in benzene hydrocarbons and yields polymers with low to moderate gel content, d. H. up to 30%. and low to moderate molecular weight, corresponding to a viscosity in dilute solution to about 3.0. In aliphatic hydrocarbons, however, the product can contain up to contain about 45% gel, and the molecular weight is also moderately high. In any case it is the polymerization reaction is sluggish, and very high catalyst concentrations are door reaction rates required from 5 to 10% per hour.

The invention is based on the object of developing a process that uses high polymerization rates can be carried out in any hydrocarbons as the reaction medium and polymers with low gel content and high molecular weight results.

The solution to this problem is a process for polymerizing isoprene in an inert liquid Hydrocarbon in the presence of an aluminum trihydrocarbon catalyst, a titanium tetrahalide and an amine, which is characterized in that one has a catalyst used by reacting the amine, optionally mixed with a non-polymerizable Ether, with the aluminum trihydrocarbon in the inert liquid hydrocarbon and subsequent addition of the titanium tetrahalide has been prepared, wherein in the reaction medium «in molar ratio of amine to aluminum compound between 0.01: 1 and 1.5: 1 and of titanium compound to the aluminum connection between K): 1 and 1:10.

This method has "compared to the method known from Belgian patent 551 851 significant benefits. In this patent, a polymerization process is described in which complex compounds are used, which have to be isolated before they are In an inert solvent can be used together with the titanium tetrahalide as a polymerization catalyst. In contrast According to the invention, amine and aluminum tricohydrocarbon are in an inert liquid Hydrocarbon reacted, and then without isolation of the complex compound formed Titanium tetrahalide added in order to obtain a catalyst in this way, through which not only but above all increases the rate of polymerization compared to known processes the gel formation during the polymerization is suppressed in the simplest way.

Amine used as a catalyst together with titanium tetrahalide and, on the other hand, according to the invention worked show the superiority of the method according to the invention. According to the state of the art, this came about by reacting triisobutylaluminum and di-n-butylamine recovered and isolated compound

Progress in which a reaction product, prepared and isolated before the polymerization, of an aluminum compound and a] o which was dissolved in η-butane was mixed with TiCl ₄ in such amounts that in the various polymerization levels Ti / Al ratios of 0.6: 1, 0.7: 1, 0.8: 1, 0.9: 1, 1: 1 and 1.1: 1 templates, for use. 18 g of isoprene were added to each of these catalyst batches under nitrogen and the reaction vessels were left to stand at a constant temperature of 5 ° C. (water bath). After 15 days, no polymer had yet been formed. If, on the other hand, the polymerization was carried out according to the invention in the presence of a catalyst which had been obtained by combining tri-n-butylamine in η-butane and triisobutylaluminum and then adding TiCl ₄ , it was possible in significantly shorter times, namely mostly in 4 or 5 hours,> 5 also at a constant temperature of 5 C, high conversions between almost 90 and 100% can be achieved, the polymer also being distinguished by its low gel content. The exact results are given in Example 9 later, namely in Experiments B, D, F, H, J, L, N and P. . It has also been proposed to use a non-polymerizable ether as a modifying agent in conjunction with titanium tetrahalide-aluminum nitride hydrocarbon catalysts to form cis-1,4-polyisoprenes of very low gel content and high molecular weight. Some of the non-polymerizable modifying ethers have little effect on the reaction rates, but it is generally impossible to achieve rapid reactions up to high conversions and at the same time use sufficient ether to form a polymer with a low gel content.

According to the invention, by adding an amine, titanium tetrahalide -aluminium tricarbon- (hydrogen catalysts are now strongly activated when polymerizing isoprene, that is, the reaction rate is higher, the gel content of the polymer is reduced, the remaining gel is more swollen, and the molecular weight of the polymer is shifted only moderately up or down. The use of an amine in this way has a combined activating and modifying effect which results in very significant improvements in process economics and in polymer properties. When an amine is used in combination with a modifying ether enters a novel synergistic effect, with the best properties of the ether, namely ^f> "the strong suppression of gelation and the substantial increase in molecular weight, and the amine, namely the increase of the reaction rate, and combine a Polymerisati produce onsrcaktion that powerfully at high speeds up to practically complete conversion with the formation of polymers with significantly increased molecular weights, corresponding to a viscosity in dilute solution above 3,

and sharply reduced violins, d. H. under 25 "/ ,,, runs. These results are obtained without adversely affecting the stereospecific structure of the polymer products achieved. In some cases the amine even seems to favor the cis-1,4 structure.

Any amine is suitable for this purpose, and / was simple primary, secondary and tertiary alkyl amines, .vie, for example, methylamine, dimethylumin, trimethylamine, diethylamine, triethylamine, tripropylamine, Triallylamine, butylamine, dibutylamine, trin-butylamine, Triisobutylamine, trianiylamine, trihexylamine, Triheptylamine, Trioctylamine, Trilaurylamine; primary, secondary and tertiary aryl, aralkyl and alkarylamines, such as phenylamine, diphenylamine, triphenylamine, Phenyl - /; - naphthylamine, N-methylaniline, Ν, Ν-dimethylaniline, tribycylamine or tritolylamine; alicyclic amines such as cyclohexylamine and others as well as heterocyclic amines such as pyridine, N-ethylpiperidine, pyrrole, N-methylpyrrolidine, N-hexylpyrrolidine or triethylimine.

The tertiary amines, which are free from active hydrogen atoms, and the Λ simpler, low molecular weight amines, as they are used in 'lower levels appear to be more effective and more readily available in pure form are most preferred. For example, aliphatic amines are preferably used in which each alkyl hydrocarbon radical contains 2 to about 12 carbon atoms. Most advantageous are the trialkylamines, in which each alkyl radical preferably contains from 3 to about 12 carbon atoms. The last-mentioned class of amines is preferred because they have the strongest rate-increasing effect, suppress gel formation most strongly, bring about the greatest increase in the swelling index of the remaining gel and have the least influence on the final conversion. While the amine and / or the ether were referred to as "modifying agents", these substances differ from the modifying mercaptans used in free radical polymerization in that the amine and the ether, in contrast to the mercaptans, do not lower the molecular weight but increase it. Highly preferred miniumtrialkylen of the AIu- _Λ, for example, trimethylaluminum,> triethylaluminum, tripropylaluminum, tri-n-butylaluminum, triisobutylaluminum, trioctylaluminum, tri (2-ethylhexyl) aluminum and tridodecylaluminum.

Titanium tetrachloride, Titanium tetrabromide, titanium tetraiodide or titanium tetrafluoride be used. The tetrachloride and tetrabromide are similar in terms of activity, while the iodide and fluoride sometimes produce less active catalysts. With the tetraiodide a completely soluble (homogeneous) catalyst is obtained under mild conditions.

Any inert hydrocarbon which is liquid or can be liquefied at the desired working temperatures is suitable as a solvent and diluent. Such a medium must be inert, ie have a low content of substances which can react with the catalyst and the catalyst-forming constituents or with the monomers, form a complex compound or combine with them in some other way. Preferred inert substances are the aliphatic, aromatic and cycloaliphatic hydrocarbons with a low content of oxygen, water and active hydrogen-containing compounds, such as alcohols. Acids and acetylenic hydrocarbons. The simple solvents are preferred. that is, the aromatic hydrocarbons having up to 9 C atoms, and the more volatile, ie the boiling below about 15O ⁰ C aliphatic hydrocarbons having 3 or more carbon atoms per molecule is used, such as propane, h-butane, isobutane,

ίο Pentane, butene- (1), butene- (2), hexane, heptane or isooctane. Most advantageous are aliphatic hydrocarbons and mixtures thereof, which boil at pressures below about 8 kg / cm ² in the range from -10 to +50 C. Examples are η-butane, isobutane, butene- (1), butene- (2), pentane and mixtures of these and / or other hydrocarbons. The diluent increases the fluidity of the reaction mixtures. For acceptable viscosities in practical operation, it is generally preferred to use a

ίο amount of diluent of 50 percent by weight, based on the total mixture, worked. Diluent amounts of 70 to are even more advantageous 95 percent by weight of the mixture.

The reaction can be carried out at any temperature between about -70 and + 80'C. Preferably reaction temperatures of -10 to + 70 "C are used. The lower temperatures require higher amounts of catalyst, but appear to favor a higher molecular weight and a more regular polymer structure, while higher temperatures accelerate the reaction and require less catalyst, but make it difficult to obtain a high one To achieve molecular weight without lowering the catalyst concentrations to a point where high purity of the solvent and monomer and great care are required to achieve reproducibility. For this reason, a reaction temperature between about -10 and + 70 ° C is preferred. in particular between -10 and + 60 C ^u worked.

If isoprene polymers with a given stereospecific structure are desired, the Ti / Al molar ratio must be be restricted more closely. For example, the production of a polyisoprene is made with exclusive cis-1,4 structure, d. H. a homopolymer of isoprene in which 90 or more than 90% of the isoprene units are head-to-tail cis-1,4-linked are desired, the Ti / Al molar ratio must be of the catalyst between about 0.5: 1 and about 1.5: 1 lie. The reaction rates become within the latter range as the Ti / Al ratio increases lower, but high conversions are achieved with longer reaction times. With a Change in the Ti / Al molar ratio in the catalyst other changes are noted, such as changes in gel content or molecular weight. As a result, catalyst ratios between about 0.75: 1 and 1: 1 tend to be particularly useful from about 0.80: 1 to 0.95: 1 used, where

f> o the amine enables higher ratios to be used, without the gel content increasing and the reaction coming to a standstill. If a polyisoprene with a practically exclusive, trans-1,4 structure, i.e. H. to be produced with at least 90% trans-1,4 are catalysts with Ti / Al ratios between about 1.5: I and 3: 1 to use. The presence of varying amounts of water, alcohol and others However, contamination sometimes makes itself felt

noticeable from the fact that the polymerization reaction proceeds as if a shift in the Ti / Al ratio would have occurred. The homogeneous catalysts made from titanium tetraiodide are opposite more sensitive to the Ti / Al ratio. .

The total amount of catalyst, i.e. H. all components total except amine and / or ether, can be significant - largely depending on the purity of the Solvents, diluents and monomers - can be varied. Already about 0.1 to 0.2 percent by weight, based on the monomersh, can cause polymerization if special care is taken is used to dry the reactor and to dry and remove the solvents and monomers " to clean. Generally about 0.2 is sufficient. up to 10 percent by weight total catalyst, based on on monomers. Better the catalyst concentration in millimoles of each ingredient per Express liter of reaction mixture. On this basis, about 0.5 to 50 millimoles each of titanium and aluminum components can be used can be used per liter of mixture. The range from about 1 to is more advantageous 50 millimoles of each ingredient. Of course, the above-mentioned quantity ranges are compatible with mentioned above. Ti / Al MoIvriatnisscn apply. .The proportion of the amine that is required in the context of the invention, depending on the desired Results can be very different. In general is the proportion of amine that proves to be advantageous, very low. Already about 0.0! MoI amine per MoI aluminum in the catalyst makes itself stronger Violent wedge of the polymerization reaction noticeable. With an increasing amount of aminine, increased reaction rates decreased gel contents and higher molecular weights of the polymers until the amine content has reached about 0.5 to 1.0 mol per mol of aluminum in the catalyst. In the range of about However, 0.75 to 1.5 moles / mole of aluminum is sometimes found to cause the polymerization reaction starts very quickly and the speed after a violent initial period to a much lower one Value tends to decline. At amounts above 1.5 moles / mole aluminum, it becomes difficult to obtain an economical one To achieve product yield. A violent incipient reaction can occur in one on polymers Continuously operated processes directed at a low degree of polymerization are advantageous. Preferably however, from about 0.05 to about 0.75 moles of amine / mole of aluminum are used. Through suitable Choice of catalyst ratio and proportion of amine, reactions were achieved that took 30 to 60 minutes were completed.

If the amine is used with a modifying ether, which in this case is the main one modifying agent is used to reduce the gel content and increase the molecular weight, smaller amounts of amine can be used. About 0.03 to about 0.5 mol of amine per mole of aluminum in the catalyst is usually sufficient this purpose. ■

The amount of the non-polymerizable modifying agent Ether when used in conjunction with an activating amine is also used very low. Usually 0. (K) oil to 0.001 mole of ether is made per. Mole of aluminum in the catalyst noticeable through reduced gel content and increased molecular weights. , With increasing The ether component becomes stronger (reduced gel content, increased molecular weight). at about 0.3 mol of ether per mol of aluminum, a strong inhibition of the reaction can be observed in some cases, and above about 0.8 moles of ether per, mole of aluminum in the catalyst it is not always possible to achieve acceptable reaction rates. Since the amine is a strong activating agent Has an effect, amounts of ether between about 0.02 and about 0.7 moles per mole of aluminum are common sufficient. As with the amine, the best results will be with the modifying ether obtained when the ether with the aluminum compound is combined before the latter is brought together with the titanium component.

The modifying ether must not be polymerizable, ie it must be free from I-olefinic CH ₂ = C groups. Suitable ethers are the aliphatic ethers, the aromatic ethers, the mixed aliphatic-aromatic ethers and the various types of cyclic ethers. For example, aliphatic ethers such as dimethyl ether, diethyl ether, dipropyl ether, di-n-butyl ether are suitable. Methyl 1-n-bulyl ether. Diisoamyl ether, di-n-hexyl ether, di- (chloromethyl) -ätlier, Di- (/ y-chloroethyI) -diphenylether, Diphe- ♦ nylätlicr. Anisole, styrene oxide. Butadicnmonoxide, furan. Tetrahydrofuran or ethylene oxide and its condensates.

The most beneficial ethers for use as modifying agents are the high molecular weight condensed ones Ethylene oxides, which are produced by co-condensation of ethylene oxide with an active one Hydrogen-containing compound such as phenol, an alcohol, a carboxylic acid or a primary or secondary amine, with the formation of a condensate with a molecular weight greater than than about 4 (K). preferably more than about 700. These condensates have significantly lower inhibitory properties Effects and yet emphasized modifying effects. As suitable for the method according to Invention, the commercial products of this type with molecular weights from 400 to 1500 have been found or more.

When preparing the reaction mixture, care must be taken to ensure that an inert Atmosphere is maintained above the air-sensitive materials until the polymerization reaction takes place until the desired point and the catalyst by treating with a sufficient amount a catalyst killing agent, e.g. B. an alcohol, acetone, a carboxylic acid, deoxidized Water, complexing agents, amines (large amounts) and other active hydrogen containing substances that destroy the catalytic activity and the mixture towards oxygen able to make insensitive has been deactivated. By contact with oxygen in the presence the active catalyst degrades the unsaturated diene polymer. The destruction or deactivation of the catalyst is usually carried out by adding an excess of the reagent under inert Atmosphere is added to the mixture.

The deactivated reaction mixture can then, if desired, be exposed to the air and treated further to remove the polymer product from any remaining unreacted monomers, from the solvent or diluent and from Kalalysatoriestcn to separate. If one is soluble in the diluent Polymer is obtained, the reaction

mixed with alcohol, acetone or water to destroy the catalyst at the same time and extract the catalyst residues. If there is enough alcohol or acetone in the latter Treatment is used, the precipitation of the dissolved polymer usually takes place at the same time. After the catalyst has been removed, the remaining mixture can be distilled in the presence of water to deposit the polymer as a crumb suspended in water. Usually becomes a Antioxidant in one stage before final drying

incorporated into the polymer. The drying of the polymer at temperatures up to 100 ° C can be carried out in an air or vacuum oven.

For example

Isoprene is made with fine metallic sodium and then treated with molecular sieves and immediately before use in the polymerization distilled. The polymerization is with tri-n-butylto amine carried out as an activator. The reaction mixture contains the following components (in parts by weight):

attempt

Isoprene

η-butane (cleaned with molecular sieves) ...

Triisobutyl aluminum

Tri-n-butylamine

Titanium trachloride

Ti / Al ratio

100

525 3.25 0

2.80 0.9: 1 100

525
3.25
0.20
2.80
0.9: 1

100

525
3.25
030
2.80
0.9: 1

100

525
3.25
0.40
2.80

: 0.9: 1

In each case, the reaction vessel is dried well and purged carefully with dry nitrogen. It then becomes the η-butane, then the aluminum compound and the amine and, after the mixture has been stirred for a while, - lastly the titanium compound and the isoprene in the nitrogen-filled reaction vessel introduced. In the experiments activated with amine, the reaction sets in within a very short time one. recognizable by the occurrence of butane reflux in the condenser placed on the reaction vessel. In comparison experiment 1, on the other hand, the reaction does not begin until about 1 hour after use. You developed up to a steady average speed of around 10% per hour and goes in that way continue until it is practically complete in about 20 hours at a temperature of 1 to 2 C. (at a conversion of 90% or more). In experiments 2 to 4, on the other hand, the reaction does not just continue within a few minutes, but runs so fast that the average reaction rate 80% per hour. The results are summarized below.

attempt Tri-n-butylamine,
Parts per 100 parts
Isoprene Average
Reaction
speed
%.'H Mooney
viscosity Gel content
<>.
Ό Source indcx viscosity
in diluted
solution 1
2
3
4th 0 (comparison
0.2
0.3
0.4 K)
. 80
80
80 80
78
70
67 ' 42
30th
29
28 36 ,. .
65 ■ · ■ -
65
70 3.9
3.86
3.75
3.53

In any case, a thin slurry of η-butane floating, somewhat gelatinous Polymer particles obtained. In any case, the slurries are fed with nitrogen given a covered vessel containing about 5 percent by volume of methanol based on the slurry. The resulting mixture is agitated enough to ensure good contact. Then a minor one Amount of water (5 to 10 percent by volume, based on methanol) added and the mixture as long moves that extraction of the alcohol from the hydrocarbon phase is guaranteed. After standing, two layers form, an upper hydrocarbon layer and a lower aqueous alcohol layer containing the catalyst residues. The lower layer is drawn off and an equal volume of water is added to the slurry, and the stirrer is turned on and stir the mixture to ensure good extraction of the residual alcohol from the hydrocarbon layer to guarantee. The mixture is then left to stand and the lower layer of water is removed pulled. The hydrocarbon layer is washed twice more in this way with clear water.

An almost clear, alcohol-free slurry is obtained, of polymer in butane. A solution or dispersion is then added, per 100 parts Polymer 0.5 part by weight of symmetrical di - // - naphthyl-p-phenylenediamine and contains 0.25 parts by weight of diphenyl-p-phenylenediamine. Then a the same volume of water was added and the butane was distilled off at 60 to 100 C, with a practically butane-free aqueous slurry of solid, small crumbs is obtained. The slurry will filtered hot (50 to 60'C or higher) and the filter cake put on a roller mixer, where it is rolled out into pelts while washing at the same time that will be dried in a vacuum oven. The infrared investigation of the four experiments obtained polymers shows that their cis-1,4-Antcil is over 90%. From the above values it follows that that the relationship between Mooney viscosity and molecular weight (viscosity in dilute solution)

inn π J ι en

Is changed by presence.

very little of the amine

Example 2

A commercially available antioxidant made by the condensation of diphenylamine with acetone

10

and contains about 25% unreacted amine, serves as an activator in the polymerization of isoprene in η-butane (analytically pure, treated with molecular sieves). The polymerization is based on that in Example 1 described manner carried out with the same catalyst system. The following substances are used:

η-butane, g.

Isoprene, g

• Triisobutyl aluminum, cm ³

TiCl ₄ , cm ³

Molar ratio Ti / Al

Antioxidant, g

Molar ratio

Antioxidant to C ₅

Antioxidant to Al

Antioxidant to Ti

Ti / Al:.

Temperature, ^c C

Sales volume, %

Mooney viscosity

Gel content,%

Source index

Viscosity in dilute solution

In this example, the amine inhibition appeared to be very strong when more than 1 mole of antioxidant is used per mole of aluminum. However, this modified diphenylamine has a strong effect Suppression of gel formation and has a stressed

! 2 300 300 60 60 1.58 1.58 0.62 0.62 0.9: 1 0.9: 1 0.64 0 0.0053 - 0.51 - 0.57 - 0.9 1 to 2 I to 2 43.4 87.6 52 87 7th 38 129 39 3.60 2.96

attempt 3 (K) 4th 300 5 300 .1 60 60 60 1.58 1.58 1.58 0.62 0.62 0.62 0.9: 1 0.9: 1 0.9: 1 1.28 1.92 2.56 0.0106 0.0156 0.0212 1.02 1.53 2.04 1.114 1.71 2.28 1 to 2 I to 2 I to 2 17.5 13.8 5.5 4th 2 10 147 229 133 3.47 2.98 4.21

Tendency to increase molecular weight in spite of its questionable composition and purity. Here, too, the infrared investigation shows that in all polymers the cis-1,4-proportion over 90% located.

example

The procedure is the same as in Example 1, but tri-n-amylamine is used in place of the Tri-n-butylamine used. The approach has the following composition:

η-butane, g

Isoprene, cm ³

Triisobutyl aluminum, cm ^J

Molar ratio Ti / Al

Triamylamine, cm ³

TiCl ₄ , cm ³

Moles of triamylamine / moles of Al ......

Final sales,% ■

Mooney viscosity

Gel content,%

Viscosity in dilute solution test

I (comparison)

286 80 2.25 0.9:

0.88

.75.5 47

28;

2.95

From the above values it can be seen that) triamylamine activates (see higher conversions) and the Lowers gel content. According to the infrared spectrum of the polymers, it is polyisoprenes with exclusive cis-1,4 structure.

.? 4th 286 286 286 80 80 80 2.25 2.25 2.25 0.9: I. 0.9: 1 0.9: 1 0.8 0.2 0.4 0.88 0.88 0.88 0.288 0.072 0.144 46.5 81.5 82. 36 37 30th 12th 19th 13th 3.05 2.96 2.80

286

80 2.25 0.9: 0.1 0.88 0.036

89

43

23 3.07 B e i s ρ i e I 4

The experiment described in Example 3 is repeated, but using pure diphenylamine as Activator and modifying agent is used.

The proportion of diphenylamine is 0.0525 mol / mol of titanium. The gel content of a polyisoprene produced in a control experiment is 38 ⁰ Z ₀ , while the amine-modified polyisoprene contains only 20% gel. The corresponding values for the viscosity in dilute solution are 3.32 and 4.61, respectively. The reaction started very easily and proceeded very quickly during

the first hours. The final conversion (50% compared to 70% in the comparative experiment) is lower.

Example 5

In the polymerization carried out as in Examples 3 and 4, triphenylamine is used as the amine. The following results are obtained:

2 attempt 4th C. I (control 0.05 ■ j 0.2 3. attempt) 0.027 i 0.108 0.4 0 84.5 0.1 89.5 0.216 - 61 0.054 58 91.5 88.0 31 89.5 32 64 58 3.44 59 3.56 28 27 30th ρ i e 1 7 3.63 3.22 3.48 By S

Triphenylamine, g ..-

Mole / mole Al

Sales volume, %

Mooney viscosity

Gel content, ⁰ I _n

Viscosity in dilute solution

Even the very small amounts used in the previous experiments gave somewhat higher amounts Reaction rates and slightly higher values for the viscosity in dilute solution.

B e i s ρ i e 1 6

The experiments described in Examples 3 to 5 are carried out using pyridine as the amine repeated. The results obtained with 0.05 to 0.58 moles of pyridine per mole of titanium indicate that this Ainin strongly suppresses gel formation.

In experiments carried out in the same manner as in Example 1, tri-n-butylamine combined with an ether. A non-ionic surface-active agent is used as the ether, namely a condensate of a phenol with ethylene oxide, which has a molecular weight of about 15 (H). The ether and the amine are added to the solvent and triisobutylaluminum. The mixture is stirred for at least 10 minutes before the titanium tetrachloride and the isoprene are added. the Results are shown below together with the values of Example 1 given for comparison.

0 (control attempt)

0.2 (control experiment)

0.3 (control experiment)

0.4 (control experiment)

0.2

0.5

0.10

0 (control attempt)

0.5

0.5

0.5

0.5

*) Parts by weight per 100 parts of monomeric cream.

Medium

Reaction

gcsduvintliiikcit

- "Ah '

K) 80 80 80 45 32 36 6.2

Mooney
Viscose Gel content
(I
Ii Source index viscosity
in diluted
solution 80 42 36 3.9 78 30th 65 3.86 70 29 65 • 3.75 67 28 70 3.53 72 15th 103 4.19 77 20th 77 4.57 ... 73 16 94 4.41, 84 22nd 162 .4.75

From these values it can be seen that the speed-increasing Effects of the amine are strong enough to reduce the rate-inhibiting effects of the modifying Turn off ether. Since the Mooney viscosity did not change significantly, the Significantly higher values of the viscosity in dilute solution recognize that polymers of the same Plasticity but with much higher molecular weights were obtained. One that has occurred Structural change is too small to be detected with infrared rays. The polymers are Polyisoprenes with an exclusively cis-1,4 structure.

In polymerizations based on that described above Way in a large-scale batch reactor were stirred, it was found that reactions carried out without amine or ether the induction time about 1 hour and the reaction rate average about 10% / h. With the ether alone there is an induction period of about 4 hours, and the subsequent reaction rate is im Mean only 1 to 2% per hour. With the amine and / or ether, the induction time lasts at most a few minutes, and the average reaction rate is 5 to 80% per hour.

Several other cis-1,4-polyisoprenes have been identified prepared the manner described above, using an amine and ether as well as ether alone as modifying Funds were used:

Tri-n-butylamine, weight per 100 parts mono
meres

Ether, parts by weight per
100 parts monomer ...

Sales volume, % ··

Mooney viscosity at 100 '

Gel content,%

Source index

Viscosity in dilute
solution

0.5

84

85

23

117

4.92

0.1

0.5

92

84

22nd

162

4.73

From these rubber-like polymers and a pale crepe natural rubber used as a control Mixtures are prepared as follows (viscosity in dilute solution about 9):

Gcwichisicilc

Rubber 100

Stearic acid 3.0

Highly abrasion-resistant furnace soot 40.0

ZnO ... 5.0

Phenyl - // - naphlhylamine 1.0

Benzothiazyl disulfide 0.6

Sulfur 3.0

The mixtures obtained are vulcanized in the mold at 145 ° C. for 30 minutes. The received Plates are tested for physical properties according to standard ASTM methods. The following Values were obtained:

Tensile elongation properties at 100 ° C
Tensile strength, kg / cm ² ..

rr " _l0 , kg / cm-

Strain, %

Hysteresis, TC

Deformation rest in
Compression

test

Initial plasticity
according to Mooney
(ML-212 ^: F)

T ₅

T ₂₀

Durometer hardness

(vulcanized).

PaIc- A. U Crtpc A. Nature- knulschuk Tensile elongation properties properties in space 300 temperature 298 177 Tensile strength, kg / cm ² 302 183 590 223 580 Strain % 510 116 Tension at 300% 120 Elongation, kg / cm ² ... 151

PaIe-
CrCpe-
Nature-
kuuischuk A. 213 188 139 104 580 650 12.8 13.9 7% 8th% 45 43 6th 7.5 7.5 9 61 60

It can be seen from the above values that the synthetic rubbers vulcanized somewhat more slowly and were therefore not fully vulcanized. This explains the slightly higher values for the hysteresis, the deformation set and the elongation and the lower modulus valuesc and tensile strength wedge values at 100. Even so, these physical properties are quite excellent and show clearly that the rubbers of the best type of crepe natural rubber are practically equivalent and are slightly better than some of the lower commercial grades of natural rubber. It is to be expected that the differences in the above by appropriate combination of the mixtures Properties would be considerably smaller.

To compare the nature of the gel in the polymers prepared according to Example 7, these are on a roller mixer with a narrow roller gap at a roller temperature of 70 ± 5 C maslizicrt. With As mastication progresses, samples are taken after 2, 5, 10 and 15 minutes and carried out Determination of their Mooney viscosity at 4 minutes (at 100 "" C) using the large rotor examined for degradation. For comparison, natural rubber (Hevea) is masticated and in the same way examined for degradation.

In addition, the values for a polyisoprint sample are shown in the table below for comparison called, which was produced without a modifier or activator. . ι. ·

Mastikalioiis / cil. Minutes ■ ·. ·

5 ■ '45 ' ■ i ^: - ^! 58 58 ^; ; . «» · 49 ; ■■■ - ;;; 59 .. ' .:. .42. · _; . 48 '

15th

Natural rubber (viscosity number of the solution 3.57) Mooney viscosity:

Unmodified cis-1,4-polyisoprene (about 40% gel, viscosity number of the solution 3.45) .

Cis-1,4-polyisoprene modified with ether

Cis-1,4-polyisoprene modified with 0.1% amine and 0.5 "/" ether

68

65

72

57

33

54
38

35

From the above data, it can be seen that the unmodified synthetic cis 1,4-polyisoprene is degraded somewhat more slowly during mastication than natural rubber. That modified with ether synthetic cis-1,4-polyisoprene appears to be essentially have the same rate of degradation as natural rubber. The modified with amine and ether Sample seemed to have degraded to the same extent although the starting polymer was somewhat softer. The advantage of a rubber made in the processing properties is practically equivalent to natural rubber, lies in the fact that the rubber processors use their machines or methods No changes need to be made if the synthetic product in place of the natural product is used. . -

B ei s ρ i e 1 8

Tri-n-butylamine is used together with catalysts made from titanium tetrachloride and triisobutylaluminum different Ti / -Al ratios are used. The purpose of these experiments is to determine the

optimal catalyst ratio when using the amine for activation and modification. the Amine mcngc is changed at each catalyst ratio to see if it fits each ratio gives an optimal amine concentration. The ingredients and methods used are the same as described above except that the amine added to the solvent and then the aluminum compound is added. The properties of the

ίο Crude polymers (gel content, swelling index, viscosity number of the solution) and the ratio of the optical densities for the 3,4 and 1,4 structure (ratio 3.4: 1.4) are summarized below. , _: From these values it can be seen that the trin-butylamine shows increasing activation at the higher catalyst ratios. At ratios above 0.95: 1 it is usually difficult to get good yields and gel levels are 40 to 50% or higher. When tri-n-riexylamine and tri-n-heptylamine are used in place of the tri-n-butylamine, almost the same results are obtained.

Ti./AI- 'Ti + -Al Mole of amine Reaction sales volume
■. /O Gel content
■% ' Source index Viscosity ratio attempt ratio (Milliinol) MoIAl time
H 72 21 45 rah I
the solution 3.4: 1.4 A (contr.) 0.805: 1 5.03 5 89 5.7 40 2,942 0.22 B. 0.805: 1 5.03 0.193 5 83 29 36 2,896 0.21 C (contr.) 0.85: 1 6.09 - 5 100 19th 64 2,774 0.20 D. 0.85: 1 6.09 0.051 ■ 5 83 31 40 2.967 0.20 E. 0.85: 1 4.87 - 4th 95 10 120 3.657 0.19 F. 0.85: 1 4.87 0.408 4th 45 30th 34 3.466 0.22 G 0.85: 1 3,655 - 1.5 95 17th 102 3.760 0.20 H 0.85: 1 3,655 0.408 1.5 89 45 20th 3.861 0.19 I. 0.885: 1 5.96 - 22nd 100 25th 56 3.708 0.22 J 0.885: 1 5.96 0.212 22nd 17th 41, 15th . 3.842 0.21 K 0.95: 1 5.96 - 5 89 22nd 61 2.129 0.22 L. 0.95: 1 5.96 0.19 1.5 17th 56 10 - 0.20 M. 1: 1 5.96 - 5 100 21 67 1,848 0.23 N 1: 1 . 5.96 0.197 5 2 - .—. 2.943 0.24 O 1.1: 1 5.96 - 4th 100 14th 95 ■ ■ —- - - P. 1.1: 1 5.96 0.38 4th 78 41 23 3.286 0.24 Q 1.3: 1 5.96 .0.25 21.5 3.346 0.24

B e i s ρ i e 1 9

In the manner described in the previous examples, N, N-dimethylaniline is used, however in this case the amine was added to the solvent before the aluminum compound. The ingredients and results are summarized below. :

η-butane. Parts by weight
Isoprene. Parts by weight
Triisobutyl aluminum.
Parts by weight

_{TiCl 4} , parts by weight ...
Ti / Al ratio

attempt

460
100

2.15
2.37
0.885: 1

551
100

3.30
2.83
0.885: 1 N, N-dimethylaniline.
Parts by weight

Temperature! ⁰ C- .:

Sales volume, % · · '

Violin content, ⁰ A,, ...,

Source index

Viscosity number of the solution

Mooney viscosity at

100 '

₍ , ₅ ashes, ° "

Ratio 3.4 structure to
1,4 structure .-

Reaction time. Hours ...

attempt

0.341 -

- 5 to 8 79.2 ^: ■ 29 68 3.76

73 0.07

0.22

5 · ■

0.408 -.5 to 8 100

60

0.05

0.24

17th

18th

In both cases the reaction started immediately with no noticeable induction time and proceeded smoothly until

at the specified high sales. The aniline derivative used appears to be a powerful activator.

Example 10

Triäthvlamin is carried out in the 5 hours of polymerization of isoprene with the following specified reaction mixtures are used. The

Ti / Al ratio is 0.885: 1. The approach, and the procedure is the same as in example H). The following results were obtained:

Moles of triethylamine

per mole of Al

Sales volume,%

Gel content,% ..

Source index

Viscosity number of the solution ratio of 3.4- to

1,4 structure

attempt

77.7 24 46 2.793

0.20

0.027 94.4 16 71

2.817

0.19

0.0434
88.8
12th
90

2,894

0.22

0.0868 88.8

6 84

2.771

0.19

0.1736 83.4

4.3 66

2.726

0.19

0.3472, 72.2 5.1

58

2.572

0.19

Note: Exclusively cis-1,4 structure, no trans-1,4 structure detectable.

Example 11

The procedure is the same as in Example 10, but using tri-n-amylainin as Amine. The following results were obtained:

Sales volume,%

Gel content,%

Source index

Solution viscosity number ratio

3.4: 1.4 structure ......

comment

attempt

77.7 22 47 2.797

0.21

solid gel

0.0212 88.8 18 58

3.002

0.22

'0.424
77.7
13th
72
2,880

0.23

0.85 77.7

7.3 66

3.107

0.23

ΙΟ, 1696

72.2 6.2

71 2.923

0.21

0.339 66.6

8.4 41

2.912

0.21

loose, very soft CJeI

Comparison searches

In the manner described in the above examples, the polymerization is carried out at a Ti / Al ratio of 0.85: 1 with tri-n-butylamine as activator, but the amine is reacted with the titanium tetrachloride before the mixture is reacted with the other constituents is united. A solution of Ti / Cl ₄ (about 10%) in benzene is combined with the amine under nitrogen. The resulting solution is allowed to age for about 1.5 hours before it is placed in the polymerization vessel. The following values are obtained:

Moles of tri-n-butylamine / mole of Al

Moles of tri-n-butylamine / mole of Ti

Sales volume, %

Gel content,%

Source index

comment

attempt

77.7

24

49

0.0255

0.3 66.6 15 70

0.051

0.06
66.6
11
63

4>.> Ekere, s
watery
Ciel

I)

0.102

0.12

55.5 9 48

0.204

0.24 0.48 50 22.2 11.5 16 41 14th

0.408

The decreasing values for the source index u '& l the sales in the table above show because the amine does not work in the desired way if it is reacted with the titanium component beforehand.

A second series of tests is carried out in which the catalyst is prepared and allowed to age for a while before the n-tributylamine is added. Otherwise, it is done in the same way as in the above Examples worked. The following results are obtained:

N / Al ratio
Sales volume, % ·-··

ti

0.0255 44.4

I. attempt
J K '0.408
22.2 0.051
44.4 0.102
44.4 0.2 (W
22 2

From Giesen values it can be seen that the amine only destroyed the active catalyst and the reaction inhibited. In this order of addition, the amine is not a modifying agent.

■ B e i s ρ i e I 12

The polymerization is carried out as in Example 11 in the normal way with N-methyldiphenylamine as activator carried out at a Ti / Al ratio of 0.85: 1. The following results are obtained:

Moles of amine / moles of Al
Mole amine / mole Ti

Sales volume, %

Gel content,%

Source index

comment

attempt

72.3 11 91 strong

0.0347 0.0408

83.4

21

26th

C. D. E. F. 0.052 0.1 (M. 0.208 0.416 0.0613 0.1226 0.245 0.49 77.7 77.7 72.3 61.2 8th 7th 10 10 66 68 45 53

rubbery, sticky

Example 13

N-methylaniline serves as an activator in a polymerization of isoprene carried out at - 1 to TC. The input material and results are summarized below.

Moles of N-methylaniline / mole
Al

Isoprene, cm ³

Butane, cm ^J

Triisobutyl aluminum,

Millimoles

TiCl ₄ , millimoles

Ti / Al

Sales volume, %

Gel content,%

Source index

Viscosity number in solution
ratio

3.4: 1.4 structure

attempt

14th

85

1.58 1.40

33.3 43 18 3.075

0.21

0.058 14 83

1.58 1.40

88.8 34 42 3.627

0.21

C. D. F. ' F. 0.116 0.174 0.232 0.464 14th 14th 14th 14th 83 87 82 87 1.58 1.58 1.58 1.58 1.40 1.40 1.40 1.40

0.885: 1 in all attempts

77.7
33
39
3,694

0.22

67.7
19th
67
3.142

0.21

55.5
17th
91
3.883

0.25-

11.1
34

34 ■
1.607

0.23

The above values result in a clear activation and reduction in gel for the Examples B to E with a large increase in molecular weight.

Claims (5)

Patent claims: I. Process / to polymerize isoprene in an inert liquid hydrocarbon in Presence of an aluminum tricarbonate catalyst, a titanium tetrahalide and an amine, thereby g ek e η η /. e i c h η e t that you have a catalyst used, the reaction of the amine, optionally in admixture with a non-polymerizable ether with the aluminum introhydrocarbon in the inert liquid hydrocarbon and then adding the titanium tetrahalide has been prepared, with a molar ratio of Anvn to aluminum compound in the reaction medium between 0.01: 1 and 1.5: 1 and a tilane compound / aluminum compound between 10: 1 and 1:10. 2. The method according to claim 1, characterized in that that one at temperatures in the range between -70 and t-80 C, especially in Polymerizes in the range between -10 and + 70 ° C. 3. The method according to claim 1 or 2, characterized characterized in that to obtain a polyisoprene with a practically exclusive cis-1.4 structure uses a catalyst in the preparation of which a molar ratio of titanium compound for the aluminum connection between about 0.5: 1 and 1.5: 1 has been observed. 4. The method according to claim 1 or 2, characterized in that one is used to obtain a Polyisoprene with a practically exclusive tians 1.4 structure uses a catalyst in the preparation of which a molar ratio of titanium compound for the aluminum connection between 1.5: 1 and 3: 1 has been observed. 5. The method according to claim 1 to 4, characterized in that 0.2 to 10 percent by weight of the catalyst, based on the monomer, is used.