DE1495540C3 - Process for the preparation of saturated or unsaturated olefin copolymers with certain average molecular weights - Google Patents

Description

45

There are many methods of copolymerizing ethylene with α-olefins into saturated polymers known with rubber properties. However, sulfur-vulcanizable ones are of particular interest today Terpolymers, which are obtained by the copolymerization of ethylene, olefins and dienes.

The subject of British patent specification 880 904 is a process for the preparation of copolymers from monoolefins and an unsaturated endocyclic hydrocarbon. For example can according to this process so-called ethylene-propylene terpolymer rubbers, which are considered unsaturated endocyclic hydrocarbon D! cyclopentadiene contain, are produced. These rubbers can due to the double bonds by customary methods to vulcanizates with excellent physical and technological properties are processed.

For processing and especially for use in a wide variety of areas of the In the rubber sector, it is extremely desirable to use rubbers of various Mooney plasticities available. Mooney plasticity is a measure of the average molecular weight of a Polymers - similar to the mean intrinsic viscosity - if the molecular structure of the polymer remains the same.

There are only few industrially useful processes known for adjusting the molecular weights of ethylene-propylene and ethylene-propylene terpolymer rubbers. The production of rubbers with a low Mooney plasticity has previously presented particular difficulties. One method is to maintain a certain hydrogen pressure in the reaction vessel during the polymerization. This allows the molecular weights to be reduced to a limited extent with increasing H _{2 pressure.} This procedure is cumbersome because it requires pressure vessels.

Ethylene-propylene copolymers and terpolymers can be hardly degrade mechanically through a so-called mastication process like other rubbers. Such a one Machining would also require high energy consumption.

It has now surprisingly been found that the average molecular weights of saturated and unsaturated ethylene-propylene copolymers and terpolymers vary within wide limits as desired can, if one considers the volume ratios of the solvent mixtures used for the polymerization, which are composed of aliphatic and aromatic hydrocarbons, changes.

The invention therefore relates to a process for the production of saturated or unsaturated Olefin copolymers with certain average molecular weights through copolymerization of ethylene, Propylene and optionally a termonomer using catalysts on the Based on aluminum alkyl sesquichlorides and vanadium compounds soluble in hydrocarbons in the presence of solvents, which is characterized in that a solvent mixture is used is, on the one hand from at least one aliphatic hydrocarbon or cyclohexane or methylcyclohexane and, on the other hand, of at least one aromatic or halogenated aromatic Hydrocarbon consists, one being the Mooney plasticities or the intrinsic viscosities and the related average molecular weights by changing the volume ratio between aliphatic! Hydrocarbon, cyclohexane or methylcyclohexane and aromatic or halogenated aromatic hydrocarbon in the solvent mixture controls so that for the production of polymers with low molecular weights the volume fraction! more aromatic or halogenated aromatic solvent components and for the production of polymers with increased Molecular weight the volume fraction of the aliphatic solvent component, cyclohexane and methylcyclohexane increased.

Ethylene, propylene and butene can be used as olefinic monomers. The one as a ter component in the production of unsaturated terpolymer

3 4

aromatic and aromatic solvents for the ice ρ ie 1 1
Polymerization of diolefins known. Here

However, it is only about the production of In one filled with argon or pure nitrogen

cis-1,4-homopolymers of butadiene. Furthermore, 5-1 glass reaction vessel, which is equipped with a stirrer,

Although it is also an effect of the 5 a gas inlet, a gas outlet, which to the

Molecular weight increase; but with this closure of the reaction vessel against the outer

State of the art, the situation is reversed, since the atmosphere is secured by a liquid valve,

the higher the molecular weights obtained, one thermocouple each and three 50 ml dropping funnels

higher the proportion of aromatic solvent in is provided, 3 1 will be freshly distilled and over

the mix is. Filled with aluminum oxide, dried n-heptane.

Furthermore, it is from the British patent. Then, at a stirring speed of

796 845 known that in the homopolymerization 1000 rpm a gas mixture consisting of 2.51

of unsaturated hydrocarbons the polymer ethylene and 10 1 propylene, at a temperature of

sation speed can increase if one at 15 ° C for 25 minutes in the reaction vessel

Mixed solvent works that initiated at least 15.

50 percent by volume of chlorobenzene and otherwise 7 ml of a 10% solution of z. B. consist of n-heptane. On the basis of this dicyclopentadiene added dropwise to benzene and the Polybritische patent could also not be seen pre-merization with simultaneous introduction of a gas that one in the production of mixtures consisting of 52 mole percent ethylene and olefin copolymers with mixtures of aliphatic 20 48 mole percent propylene through The dropwise addition of the catalytic and aromatic or halogenated aromatic components A and B started. The catalytic solvents by varying the quantity sator component A consists of a solution of ratios of aliphatic! to aromatic or 0.311 g of VOCl ₃ in 30 ml of benzene, the catalyst-halogenated aromatic solvent has an adverse component B from a solution of 2.72 g of Al ₂ C ₂ H ₅ Cl ₃ flow of the molecular weight in the specified 25 in 41 ml of benzene. After the start of the reaction, the way can reach. Such a valve can be clearly recognized by the suction effect in the liquid as aromatic solvents, the metering speed that mixes with the aliphatic solvents used at the same time as the catalyst components and the gas is controlled so that the mixture feed is regulated so that the introduced Amount z. B. benzene, toluene, xylene or ethylbenzene. 30 in gas mixture is equal to the converted. In this

As aromatic solvents, such cases can be used at constant temperature which can be used at the same time in the reaction vessel, and the resulting mix deten aliphatic solvents, such. B. Polymer must be an ethylene-propylene-benzene, Toluene, xylene or ethylbenzene. That of the introduced gas mixture

Pentane, hexane and heptane are examples of 35 equivalents. The gas mixture is previously listed in a 40-1 suitable aliphatic hydrocarbon. Pressure bottle has been manufactured. The outlet pressure It is advantageous to use components that are 8 atmospheres. The amount absorbed per time has a lower boiling point because it is easier to extract it from the polymers on the basis of the pressure drop in this unit, as a higher mixed bomb pursued.
. boiling hydrocarbons. 40 To ensure an even distribution of the unsaturated

In Fig. 1 the Mooney viscosity ML-4 is to achieve -100 ° C bonds in the polymer chains

and in Fig. 2 the mean intrinsic viscosity as a dicyclopentadiene solution added dropwise to the extent that

relative measure of the average molecular weight such as the uptake of the ethylene-propylene gas mixture

in each case against the mixing ratio benzene / n-Hep- takes place,

applied in tan. 45 From Table I the further course of the poly-

This can be seen from the increasing amount of aromatic merization. According to the table I

Hydrocarbon component - the reaction time given in this example is the polymerization

Benzene - the molecular weight lowering achieved was canceled by adding 5 ml of methanol. To the

The effect for an ethylene-propylene-dicyclopentadiene work-up is the clear polymer solution first

polymeres can be seen from the curves in FIG. 1 and 50 with the same volume of a 2% aqueous

F i g. 2 clearly visible. HCl solution with the addition of 50 ml of ethanol and

All polymerization batches required for the installation are then washed acid-free with water. The PoIy

this dependency were evaluated, are under merisat is then precipitated in alcohol and

exactly uniform conditions, with the exception of the dried,
in terms of the method of the invention varied 55

Ratios of aliphatic S '/ aromatic solvent yield: 110 terpolymer,

tel. Propylene content: 55 mol percent (according to the IR

The particular advantage of the procedure is determined by the Er method),

Finding is that you can very easily dicyclopentadiene content: 5 percent by weight

if desired within practically unlimited limits 60 (determined according to the iodine chloride method),

one for the processing and the physical-techno- ML ₄ -IOO ⁰ C *): 140,

logical properties of polymers extremely [? _? ] in cyclohexane at 32 ^o C **): 2.50 (c = g / 100ml).

important property, namely the molecular weight,.) Mooney viscosity measured after heating for 4 minutes

can adjust exactly. to 100 ° C.

It is possible to use the method of the invention with 65 **) mean intrinsic viscosity = mean intrinsic viscosity, the known influencing of the molecular jg ™ ^by extrapolating the concentration c in the balance by varying the temperature and / or ij ",".
to combine the catalyst concentration. c ^{au u} '

Example 2

This example shows how the intrinsic viscosities [η] and the Mooney plasticities steadily decrease with increasing amounts of benzene - as an example of an aromatic hydrocarbon - in an aliphatic-aromatic hydrocarbon mixture. The aliphatic component in this case is n-heptane.

The polymerizations were otherwise exactly under the same conditions - as in Example 1 - accomplished.

From Table II and FIGS. 1 and 2 is the molecular weight lowering effect according to the invention to see clearly.

From Table II it is particularly clear that all polymers have the same ethylene-propylene-dicyclopentadiene composition. Because the production conditions are completely the same, it is to be expected that there will be no structural differences between the polymers. Thus, the specified intrinsic viscosities [??] and the Mooney plasticities ML ₄ -IOO ⁰ C must be a measure of the molecular weights.

Table I.

5
time Katal)
A ¹ ) ^ sator
B ² ) Dicyclo
pentadiene
Solution ³ ) Tem
po Consumption ⁴ )
Ethylene
Propylene
mixture (Min.) (ml) (ml) (ml) (° C) (atü) 0 0 15th 7th 15th 0 5 9 20th 14th 15th 0.2 15th 16 29 25th 15th 0.6 30th 28 36 44 15th 1.3 15 ⁴⁵ 29 40 61 15th 1.8 60 30th 41 70 15th 2.0 135 - - - 19th

^x ) A = 0.311 g VOCl _{3 dissolved} in 30 ml benzene.

² ) B = 2.72 g of Al ₂ C ₂ H ₅ Cl _{3 dissolved} in 41 ml of benzene.

³ ) Dicyclopentadiene solution = 7 g of dicyclopentadiene in 70 ml of n-heptane.

⁴ ) Ethylene-propylene mixture = 52 mol percent ethylene, 48 mol percent propylene.

Table II Polymer Properties

attempt n-heptane benzene benzene Uj] *) ML ₄ -IOO ⁰ C Propylene **) Dicyclo
pentadiene Polymer
yield No. volume (Weight (ml) (ml) portion (Mole percent) percent) (G) ^ *** \ 3000 0 0 2.50 > 140 44.0 6.4 109 2 2700 300 0.1 1.95 75 44.2 6.7 110 3 2400 600 0.2 1.72 68 44.8 6.3 110 4th 2100 900 0.3 1.58 52 44.5 6.2 109 5 1800 1200 0.4 1.48 42 45.0 6.6 111 6th 1500 1500 0.5 1.37 26th 44.0 6.5 109 7th 1200 1800 0.6 1.29 23 44.2 6.3 112 8th 900 2100 0.7 1.20 20th 44.2 6.2 109 9 600 2400 0.8 1.12 16 44.8 6.3 110 10 300 2700 0.9 1.08 14th 45.0 6.4 110 11 ***) 0 3000 1.0 1.05 11th 43.8 6.4 109

*) Measured in cyclohexane at 32 ° C, c = g / 100 ml.
**) The determinations were carried out on molten films by the IR method. Method accuracy: + 1%

with 5 measurements each.
***) Comparative tests.

Example3

If toluene is used instead of benzene, then under the otherwise identical conditions as in Example 1 and 2 given, achieved almost the same results as given in Table II are. The same applies to chlorobenzene.

Example 4

Is carried out according to the same procedure as in Example 2 - only with the difference that instead of n-heptane η-hexane or cyclohexane is used - within the error limits the the same results as given in Example 2 were achieved.

Example 5

If you work according to Example 2, only with the difference that no dicyclopentadiene is used, in this case, too, the molecular weight-lowering effect occurs in the resulting saturated one Ethylene-propylene copolymers to the same extent as shown in Example 2 in appearance.

1 sheet of drawings

Claims (3)

Patent claims: 1. Process for the preparation of saturated or unsaturated olefin copolymers with certain average molecular weights through copolymerization of ethylene, propylene and optionally a termonomer using catalysts based on Aluminum alkyl sesquichlorides and vanadium compounds soluble in hydrocarbons in Presence of solvents, characterized that a solvent mixture is used, which on the one hand consists of at least an aliphatic hydrocarbon or cyclohexane or methylcyclohexane and on the other hand of at least one aromatic or halogenated aromatic hydrocarbon, being the Mooney plasticities or the intrinsic viscosities and the related average molecular weights by changing the volume ratio between aliphatic! Hydrocarbon, cyclohexane or methylcyclohexane and aromatic or halogenated aromatic hydrocarbon controls in the solvent mixture in such a way that one for the production of polymers with low molecular weights the volume fraction of aromatic or halogenated aromatic Solvent component and for the production of polymers with increased molecular weight the volume fraction of aliphatic solvent component, cyclohexane or methylcyclohexane elevated. 2. The method according to claim 1, characterized in that one hydrocarbons with low Boiling points begins. 3. The method according to claim 1 or 2, characterized in that the molecular weight setting with a known impairment Flow of the molecular weight by varying the temperature and / or the catalyst concentration combined.