SU366723A1 - Method for producing statistical divinyl styrene rubbers - Google Patents

Description

The present invention relates to the process for obtaining divine silneic elastomers for use in shea, rubber, 1st-tech products, rubber shoes, and so on.

A known method of obtaining statistical diphenylstyrene rubber solimerizhey Shgei di Nile and styrene in hydrocarbon solution}), 1 body. The polymerization initiator is a lithium-organic compound of the type .f. where, and - aliphatic, Naphthenic or aromatic hydrocarbon radical. The feed of the molomer mixture into the reaction zone of the slopes is continuous and slower than the polymerisation reaction at a given temperature, the concentration of myomers T of the organolithium compound. This produces polymers containing not more than 2% block polystyrene.

However, this method is different in that it cuts: the new mixtures obtained "on the basis of this copolymer" have "high strength before vulcanization, which often results in the deformation of the products.

The purpose of the present invention is to develop such a method of obtaining a statistical copolymer, in which the distribution of styrene in the polymer chain provides the necessary strength of the rubber mixture, but does not affect the iBce other properties.

This is achieved by using as the initiator of copolymerization of divinyl and styrene polymeric lithium orgic compounds containing two ltm atoms at the ends of the macromolecule, and feeding the mixture of monomers into the reaction zone at a rate equal to or exceeding up to 10% the copolymerlization rate — the growth rate of 1p. under conditions (temperature, concentration of initiator and monomers, viscosity of the polymerizate, stirring speed, etc.).

At the same time, styrene is distributed in the polymer. In the center of its molecule is small, and when approaching both ends of the chain, its quantity grows and the chains terminate at the styrene blocks, which constitute m and 1-

6% by weight of polymer "L. And 8-24% of the total styrene content.

A direct correlation was found between: age, strength and rubber mixtures, and the content of block polystyrene in the polymer

and at the same time it is shown that polymers

having a styrene block toltso on od / nom

end of the chain, have significantly less

durability of rubber compounds.

In tab. I presents comparative data on the strength of rubber mixtures of NK and various synthetic rubbers. All results were obtained on the same equipment. And with the use of the same ingredients.

Table 1

When increasing the content of block polystyrene. Above 4-5 1, the decrease in the physical and mechanical properties of the resistive material: tensile strength, relative elongation

From the comparison table. 1 and 2, it follows that for statistical copolymers of dinyl and styrene, the best set of properties, both in the range of volcanic indicators, and in other materials (rubber mixtures, really lies in a rather narrow range of the content of block polystyrene (2-6 %) and the strength of raw rubber compounds in the optimal case is close to the strength of natural rubber.

The invention is illustrated by examples.

Example 1. In an autoclave with a capacity of 6 liters of stainless steel, equipped with a shirt for heating and cooling, a stirrer, a monometer, a thermometer, fittings for supplying inert gas, components of the polymerization mixture and discharging the polymerizate, load 1 l of toluene and 16 ml. 4 N solution

nt. d. 2 summarizes the dependence of the properties of vulcanizates on the content of block polystyrene in rubber at obi; it has a styrene content of 25%.

table 2

Polymer grade

Dil.PitiPolyDi.Vi1NiLa. The temperature of the paCTiBOpa is raised to 60-65 ° C and at a rate of 650 ml / hour. The mixture is continuously supplied from 2900 ml of toluene, 760 ml of divinyl, 170 ml of styrene.

After the termination of the feed, the temperature is raised to 70-75 ° C and the polymerisation is maintained at this temperature for another hour.

The degree of co-version of Monomierov is 100%. The polymer was isolated with an alcohol containing 0.2% ionol, and it was charged with a. Titoxide. On a laboratory roll at 80-90 ° C. Polymer yield, g582

Stiffness according to defo700

The total content of styrene,% 24.8 Content of block styrene, i% 3.5 Strength of raw rubber compound, kg / cm 7.3

Example 2. In Example 1, a polymer is obtained, characterized in that. that the mixture is delivered at a rate of 500 ml / hour.

Polymer yield, g576

Stiffness according to defo650

The total styrene content,% 24.6 The content of block styrene,% 2.6 The strength of raw rubber; -m "; and, kg / cm 6.8

Lreemer 3. Through the apparatus described in the example of the lev, the dyne or styrene mixture (monomer concentration is 17% by weight, styrene: dIBI. 25: 75 ratio) is continuously passed at an average rate of 600 ml / hour, at the same time a solution of dilithium polyvinyl is given at the rate of 0, 06 g of active lithium per I kg of the amount of monomers. The polymerization temperature is maintained within 66 ± 4 ° C.

After reaching the stationary mode, when sampling FROM the second such apparatus, in series with the first, it was established that the degree of monomer conversion is –1007 °

Defoe stiffness 630

Obsh, its styrene content,% 25.1

Block styrene content,% 2.2 Raw rubber strength

mixes, kg / cm 5,3

Note. The total styrene content was determined refractometrically at

25 ° C.

The content of block styrene was determined by the method of oxidation by hydroperoxide in the presence of tetroxide and axis.

The subject is “invented

The method of obtaining statistical divi-palstyrene rubbers by copolymerising divinyl with styrene in a hydrocarbon solvent at a temperature of from -20 to 120 ° C in the presence of a lithyorgalic initiator with the continuous introduction of a mixture of monomers into the reaction zone, in order to improve the properties of the rubbers produced and rubber mixtures on their donkey, as the initiators, dilithium polymer compounds are used, for example, dilute polyvinyl, and the mixture of monomers is introduced into the reaction zone soon equal to the rate of monomer copolymerization or exceeding the latter by no more than 10%.