SU247145A1 - - Google Patents

Description

METHOD OF OBTAINING ETHYLENE COPOLYMERS WITH DIEN

OR TRIPLE ETHYLENE COPOLYMERS WITH PROPYLENE

And dienome co-polymerization in solutions

Methods are known for the preparation of rubber-like copolymers from ethylene and alpha-olefin, for example, from ethylene and propylene, by copolymerization in solutions in the presence of a Ziegler catalyst at. temperature from -80 to + 125 ° C under atmospheric pressure.

However, such copolymers are difficult to cure due to saturation.

The elastomers obtained according to the invention retain exceptional resistance to ozone, atmospheric agents, elevated temperatures, chemical agents and good mechanical properties. This is achieved by selecting non-saturated structural elements for incorporation into the elastomer and their number in the copolymer. According to the invention, elastomers with valuable properties are obtained by having at least one double bond in the polymer per 50 ethylene-olefane units, in particular, 50 ethylene-propylene units. However, regular

The distribution of double bonds in the triple copolymer causes complete and uniform cross-linking of the molecules during the vulcanization process. Ternary copolymers, which, before vulcanization, are practically in an amorphous state, after vulcanization, form valuable products that can be used to produce electrical cables, conveyor belts, tubes, tires, and other products.

For the preparation of elastomers capable of vulcanizing with sulfur or using radial polymerization initiators, it is proposed to use a dithiodine of the formula R - CHg - S - R - S - CHzR as a diene, where

R is a hydrocarbon saturated chain containing 1-10 carbon atoms, and R is identical or different radicals containing 3-30 carbon atoms and one olefinic bond.

The radicals R and R correspond, for example, to the following formulas

34

Examples of such dithiodienes are dimethyl-1-9-dithio-4-6-nonadiene-1-8

247145

.GH, S-CRf-S-G-Rf-CE-- C heteram etil-1 -10-dithio-4-7-decadien-1 -9 C CH-CHg-S-SNHCHa.

These dienes containing sulfur can be homopolymerized or co-polymerized only with ethylene or mixed with an alpha-olefin.

In copolymerization with olefia, one of the double bonds of dithiodien participates in the copolymerization reaction, and the second remains free for subsequent crosslinking reactions. This is found when examining the copolymers produced by infrared radiation. Calcium reveals the unsaturation of the copolymer, which determines the possibility of subsequent vulcanization with sulfur.

The copolymerization catalyst is an alkylating compound of one or more metals from groups I, II, or III of the periodic system of elements (A) and a halogen-substituted transition metal compound from one of groups IVb, Vb or VIb (B).

To form a catalytic system, component A can be mixed with compounds B prior to their introduction into the reactor. Thus, the catalyst can be pre-formed and, if necessary, subjected to "aging." It is then introduced into the polymerizable mixture in a continuous or batch process. Components A and B are included in the process separately.

The preferred molar ratio of metal A to transition metal B in the catalytic system is in the range from 1 to 30.

The polymerization is carried out in the presence of a combined solvent or with an excess of one of the monomers to form the liquid phase of the reaction medium. The solvents used may be the same as those commonly used in the polymerization and copolymerization of olefins, namely, aliphatic, cycloaliphatic, aromatic hydrocarbons, such as heptane, cyclohexane, benzene, ethylbenzene, or mixtures of these solvents. It is also possible to use halide derivatives of hydrocarbons that are inert with respect to the catalyst, for example chlorobenzene, tetrachlorethylene.

The copolymerization is carried out preferably at a temperature of from -30 to -f 50 ° C. Usually the applied pressure is 1 --- 10 atm, working under a higher or lower pressure. In particular, it is sometimes advisable to carry out the reaction with such

CH,

temperature and pressure, so that one or more of the available monomers are liquid during the reaction and thus serve as a distribution agent. Dithiodium is introduced into the reactor by itself or in a solvent before the addition of the catalytic system.

The proposed method can be carried out continuously. In this case, the solvent, the monomers and the catalytic system are continuously fed to the polymerization region at such a rate that their residence time there is sufficient to obtain the desired concentration of copolymers in the reaction mixture.

Typically, the desired residence time is reduced if the concentration of monomers and catalysts in the feed mixture is increased.

In new products, in particular in terpolymers, the lower limit of the ethylene content is not regulated, but the higher limit should not transform 75 mol. o / o to avoid crystallinity of the polyethylene type. The alpha-olefin content of amorphous terpolymers can range from 5 to

75 mol. % The total content of dithioalkene in the terpolymer, i.e. the group obtained by the copolymerization of dithiodine, can vary from 0.1 to 20 mol. The copolymerization duration, depending primarily on temperature and the nature of the catalytic system, usually varies between 1 and 8 hours.

At the end of the process, the catalyst is removed by known methods, and the reaction medium, solvents and unreacted monomers are distilled off under vacuum with steam at a temperature of 30-60 ° C. The resulting copolymer or rubber is vacuum dried at 40 ° C.

The product is unsaturated enough to be cured by the methods used for unsaturated elastomers.

Example. The reaction is carried out in a cylindrical glass reactor with a capacity of

1000 cm, equipped with a stirrer, thermometer, two ampoules for the introduction of the catalyst and cocatalyst, a cooler with a tube for the removal of gases, a tube for the release of gases. This tube terminates at the bottom of the col CH 8-CH 2 CH: C: CH 3 reactor.

for better diffusion of the gaseous mixture into the solvent. The reactor is placed in a thermostatic bath, adjustable to -5 ± 1 ° C.

Gaseous monomers, purified from traces of moisture and air, with a feed rate controlled by rotameters and counters, are mixed before being introduced into the reaction medium. 400 ml of cyclohexane containing 20 vol. Vol. Is introduced into the reactor under a stream of nitrogen. % heptane and I g of dimethyl-1,9-dithio-4-6-nopadien-1-8.

6 ml of a mole of VoCb diluted to 150 L / цикл with a mixture of cyclohexane - heptane and in another - 30 ml of a molar (C2H5) 2A1C1 diluted with the same mixture to 150 ml were introduced into one of the ampoules above the reactor under nitrogen atmosphere.

Stop the transmission of nitrogen and a mixture of ethylene and propylene is fed to the reactor in the amount of 70 l / h. The volume ratio of propylene: ethylene is 2.33. After 5 minutes, maintaining the same feed rate, the propylene: ethylene ratio was adjusted to 0.5 and the calculated number of components of the catalytic system was added dropwise over 30 minutes.

Every 5 min. Measurements of the temperature and the inlet and outlet counters allow the reaction to be monitored and the absorption of gases noted. When absorption ceases (after 7 hours), 150 ml of water is poured to deactivate the catalyst. The reaction mixture was freed from the solvent by vacuum distillation with steam at 50 ° С. The output of rubber 20

Subject invention

The method of obtaining copolymer of ethylene ethylene with a diene or ternary copolymers of ethylene with propylene and diene copolymerized in solutions in (The presence of a Ziegler catalyst

at a temperature of from -80 to H-110 ° C under a pressure of 1 to 10 atm, characterized in that, in order to obtain elastomers that can be cured by heating or using radical polymerization initiators,

diene is used dithiodine, formula CHa-S-R-S-CHaR, where R is a saturated hydrocarbon chain containing from 1 to 10 carbon atoms, R and R are identical or different radicals, from 3 to

30 carbon atoms and one olefinic bond.