UA10865U - A method for producing low molecular rubber - Google Patents

Abstract

A method for producing low molecular rubber is performed by the thermal destruction of original high-molecular rubber. 10-90% of original high-molecular rubber is continuously supplied to the extruder, which provides warming up the original high-molecular rubber on the head to the temperature of not higher than 120 оС with subsequent continuous incorporation of the remaining part of original high-molecular rubber and the rubber after reactor to carry out thermal destruction at 150-380 оС and atmospheric pressure. Simultaneously, the thermal destruction volatile products are withdrawn with return to the reactor of 20 % of volume of the total amount of thermal destruction volatile products. The melt obtained in the reactor is supplied for mixing with the solvent preliminarily heated to 120-150 оС, and the obtained solution is filtered. As the original high-molecular rubber used are substandard cis-1, 4-polyisoprene, butyl rubber or triple ethylene –propylene rubber.

Description

Description of the invention

The useful model refers to the chemical industry, namely: to the processing of waste from the production of 2 synthetic rubbers. In connection with the growing volumes of rubber production, the problem of disposal of waste from their production is becoming very urgent.

The products obtained during the processing of such waste are returned to industry and are widely used in the production of glue, mastics, paints, additives, and plasticizers.

Thus, the method concerns the processing of substandard synthetic rubbers that do not meet the requirements of 70 technical conditions for such important indicators as viscosity, the content of mechanical impurities, ash, catalyst residues, gel, etc.

There is a known method of obtaining low molecular weight butadiene rubber by destroying rubber waste

SKD I|Experiment of utilization of industrial waste of synthetic rubber. Come on! reported G. Efremov, 1980, December 17-19, 1980, pp. 21-221. 12 The method of thermal processing of polymer waste from the production of polyisobutylene, butyl rubber, as well as stereoregular cis-1,4-polyisoprene and cis-1,4-polybutadiene at 280-450 9C is also known (see ibid., p.29-30).

The destruction of polyisobutylene and butyl rubber at 300-450 9C was accompanied by the release of gas containing 85-9506.90 isobutylene; liquid products, which are mainly isoolefinic carbohydrates. During thermal processing of polybutadiene in the temperature range of 380-450, liquid products (olefinic carbohydrates) and resinous substances were obtained as target products, the output of which depends on the temperature and time of destruction. The obtained products were used as plasticizers in rubber compounds.

The disadvantage of these known methods is the low yield of target products. There is also a known method of obtaining low-molecular ethylene-propylene rubbers by thermal destruction of the original high-molecular rubbers through three-zone processing of polymer raw materials (high-molecular rubber): in the first zone, the loaded raw materials are heated to 100-2500C, in the second zone, the process of thermal destruction takes place at o) a temperature of 150-3009C and a pressure of 10-8 VOkPa, and in the third zone, the process of thermal destruction is carried out at 200-3502С and a pressure of 10-90 kPa (KO patent 2119504, 1998).

But this method, which is the closest to the proposed useful model, in terms of its technical essence and the achievable result, does not allow obtaining a final product with a narrow molecular mass distribution (MMP), which indicates that the process is unstable. oh

The useful model is based on the task of creating conditions for obtaining a target product with a narrow molecular weight distribution (MMP up to 1.6), which will allow it to be used to obtain glue with high adhesion, mastics, paints that form durable coatings, as well as highly effective additives to petroleum products and obtaining a quality product when using substandard rubbers. -

The problem is solved by the fact that in the method of obtaining low-molecular rubber by thermal destruction of the original high-molecular rubber according to a useful model, 10-9095 of the original high-molecular rubber is continuously fed to the extruder, which ensures heating of the original high-molecular rubber on the head to a temperature not higher than 1209, followed by continuous by introducing a part of the original high-molecular rubber that remained and the rubber after the extruder into the reactor for thermal destruction at 150-3809C and atmospheric pressure with the simultaneous removal of volatile products of thermal destruction and returning to the reactor until 2006.95 from the total amount of volatile products thermal destruction by feeding the melt obtained in the reactor for mixing with a solvent preheated to 120-1509C and filtering the resulting solution, and as the initial high molecular weight rubber, non-standard cis-1,4-polyisoprene, butyl rubber or ionic ethylene-propylene rubber. - Non-standard rubber used in the method is a polymer that does not meet the requirements of the technical conditions of av! by viscosity, mass loss, mass fraction of catalyst residues, mechanical impurities, gel, etc. According to the proposed useful model, low-molecular rubbers are obtained from the corresponding starting rubbers in the form of solutions of different concentrations and in different solvents, depending on the field of application of low-molecular rubber

Ge") 20 and at the request of the customer. Thus, the product of thermal destruction, which is to be used as an additive to oils, is dissolved in industrial oil grades 1-20, 1-40. sl Example 1.

The process is carried out continuously. Chopped pieces of cis-1,-1,4-polyisoprene (content of mechanical impurities 1.bmas.9o) are fed to the entrance of the extruder (7/5 by mass.9o of the total amount), the temperature at the head 59 of the extruder is 1100C, after the extruder the polymer enters the reactor , at the same time, 25 wt. 90 s of the original rubber are fed there. The reactor for carrying out thermal destruction is a vertical cylindrical device, equipped with fittings for the introduction of starting substances, the output of the polymer melt, the removal of volatile products and the recirculation of their part, as well as temperature sensors and flow regulators. During the process, the temperature varies between 150-3800С.

Volatile products are removed from the reactor and directed to condensation. Uncondensed CO and CO 25 gases are removed to the atmosphere. The polymer melt from the reactor enters a mixer filled with a solvent heated to 1302C, where, during intensive mixing, rubber is dissolved and thermal destruction is completed. 10о06б.95 volatile products of destruction (from the total amount) are returned to the reactor. From mixer 65, the polymer solution, containing undissolved impurities and gel, enters the filters, and then into the target product collector, from where samples are taken.

The resulting rubber has a molecular weight (MM) of 3000, MMR of 1.5.

Example 2.

The process is carried out as in example 1, except that substandard butyl rubber is used as the starting rubber (it does not meet the requirements due to excess viscosity), ZOmas.9o of the starting rubber is fed directly into the reactor, the temperature at the extruder head is 1209С.

The resulting rubber has a molecular weight (MM) of 2000, MMR of 1.5.

Example 3.

The process is carried out as in example 1, except that SKEPT - 70 ethylene-propylene-norbornene rubber is used as the starting rubber, which is recognized as substandard due to the excess mass fraction of catalyst residues. Low molecular weight rubber with a molecular weight (MM) of 2500 MMR, 1.4 is obtained.

The use of the obtained low-molecular rubber in the amount of tMas.9o as an additive to 1I-40A oil gives the following results: viscosity at 10020-10 cSt, viscosity index 98.

Claims (1)

The formula of the invention is the method of obtaining low-molecular rubber by thermal destruction of the original high-molecular rubber, which is characterized by the fact that 10-90 95 of the original high-molecular rubber is continuously fed to the extruder, which ensures the heating of the original high-molecular rubber on the head to a temperature not higher than 120 °C, with the subsequent continuous introduction part of the initial high-molecular rubber that remained and the rubber after the extruder to the reactor for thermal destruction at 150-380 es and atmospheric pressure with the simultaneous removal of volatile products of thermal destruction and returning to the reactor at 20 rpm. 95 from the total amount of light-salt products of thermal destruction, by feeding the melt obtained in the reactor for mixing with a solvent preheated to 120-150 2C, and filtering the resulting solution, with non-condensing cis-1,4-polyisoprene, butyl rubber or triple ethylene-propylene rubber. Official bulletin "Industrial Property". Book 1 "Inventions, useful models, topographies of integrated MU microcircuits", 2005, M 11, 11/15/2005. State Department of Intellectual Property of the Ministry of Education and Science of Ukraine. c "c) h- - with . and? - («c) (ee) b 50 sl c 60 b5