SU988831A1 - Method for controlling emulsion polymerization in manufacture of butadiene-styrene rubber - Google Patents

Description

The invention relates to the control of the polymerization process of butadiene with styrene and can be used in the production of styrene butadiene rubbers.

A known method for controlling the polymerization process of synthetic rubbers in a battery of sequentially installed polymerization agents, concludes with. The fact that the change in temperature and flow rate of the modifier in each subsequent polymerizer is carried out depending on the size of the integral heat removal in all previous polymerizers during the residence time of the reaction mixture in these polymerizers 1.

The disadvantage of the known method co-j, is that the value of the integral heat removal characterizes not the quality of the product obtained, but only the amount of conversion of monomers. This leads to the fact that the regulation of this method lacks OPPORTUNITY; ACCURATE polymer quality control.

The closest to the invention according to the technical Essence is the method of regulating the process of emulsion / polymer polymerization in the production

styrene-butadiene rubber by changing the flow rate of the modifier supplied to the input of the polymer battery, depending on the average molecular weight of the polymer and the output of the polymerisation battery 2.

The disadvantage of this method is that the average molecular weight of the polymer, in particular the viscosity

10 polymer Mooney, does not characterize the plastic properties.

The purpose of the invention is to increase the stability of the plastic properties of the polymer.

15

This goal is achieved by the fact that according to the method of regulating the process of emulsion ce of pization in the production of styrene-butadiene rubber by changing the flow rate of modifier supplied to the input of the battery of polymerizers depending on the average molecular weight of the polymer. ra at the output of the polymerization battery, adjust the amount of flow

Claims (2)

25 modifier depending on the ratio of the molecular weights of the monomer units in the copolymer measured at the output of the polymerization battery, while increasing the value of the ratio to increase the flow rate of the modifier. and vice versa. The method is illustrated in the drawing, in which a schematic diagram of the automatic control system is presented, intended for the implementation of the proposed method. The diagram shows the pipelines for supplying divinyl 1, styrene i and modifier fixer 3, polymerization agents 4 and 5, latex pipeline. B, sensitive elements of consumption of divinyl 7, styrene 8 and modifier 9, regulator of consumption of modifier 10, regulator 11, analyzer an average molecular weight of 12, analyzed by unreacted divinyl. and computing unit 14. The control system operates in the following manner. Pipeline 1-3 transfers polyvinyl 4 to divinyl, styrene and the modifier. The battery of polymerizers in the diagram is conventionally shown by two polymerization agents 4 and 5. Pipeline 6 from the last polymerization agent outputs the product of a polymerization reaction - latex, which contains divinyl copolymer with styrene, as well as having reacted with EU divinyl and styrene. The costs of divinyl, styrene and modifier are measured by sensing elements 7-9. The flow rate of the modifier is regulated by the regulator 10 with an impact on the regulator 11 installed on the supply line of the modifier. The average molecular weight of the polymer is measured by an analyzer 12, and the concentration of unreacted divinyl by analyzer 13. The circuit contains a computational unit 14, which receives signals from sensing elements 7 and 8, as well as analyzers 12 and 13. A numeral unit calculates the ratio of the molecular weights of the comonomers in a single weight of the polymer by the equation. , "TsTvIvvp T where - GA - divinal consumption, Gjj -. styrene consumption; Cn is the initial concentration of vinyl (given); Sc is the final concentration of unreacted divinyl If the current value of the ratio is higher than the specified one. Tie. divinyl polymerization reaction prevails; computing unit 14 changes the task to the Yun controller increases the modifier consumption (and vice versa). The ratio of the molecular weights of the comonomers, in the polymer, determines the constant properties of the polymer, therefore stabilization leads to a smaller variation of the main plasticity index of the polymer — Mooney polymer viscosity. The data presented in the table. Change interval Mooney polymer viscosity Calculations show that using the method improves the Mooney polymer viscosity stability, which makes it possible to obtain an economic effect in the national economy of the country by increasing the service of rubber products made from this product. The invention The method of regulating the process of emulsion polymerization in the production of styrene-butadiene rubber by changing the flow rate of the modifier supplied to the input of the polymer battery, depending on the average molecular weight of the polymer at the output of the polymerisation battery, is given with. By improving the plastic properties of the polymer, the modifier consumption is adjusted depending on the ratio of molecular weights of the comonomer units in the copolymer, measured at the output of the polymerization battery, while increasing the modifier consumption, and vice versa. Sources of information taken into account in the examination 1. The author's certificate of the USSR 510925, cl. G 05 C 27/00, 1976.. 2. USSR author's certificate number 557582, cl. G 05 D 27/00, 1978. (Prototype).