Nitrile rubber production process

Abstract

The invention relates to the technical field of rubber production, aiming to provide an improved nitrile rubber production process, which comprises polymerization, degassing and condensation. Raw materials including acrylonitrile, butadiene, desalinated and deoxidized water, condensed water and molecular weight regulators are fed into a polymerization position, convergence is carried out in a header pipe at the polymerization position, the converged mixture is pre-emulsified sequentially through a pipe pump and a pipe mixer, heat exchange is carried out through an ammonia-cooling heat exchanger for cooling, the cooled mixture, initiator emulsion and activator solution are sequentially fed into a plurality of reactors for polymerization to produce latex, the latex taken out of the reactorsand terminating defoamer solution are fed into a maturing reactor and are fully mixed when the rate of polymerization and conversion reaches 70 plus or minus 5 percent, and the mixture is then fed into a degassing tower to be degassed and into a condensation reactor for condensation. The problem of blockage of the heat exchanger can be avoided, the process is simple, the production process is stable and economical, the Mooney of rubber can be controlled easily, and the produced nitrile rubber has high quality.

Description

technical field [0001] The invention relates to the technical field of rubber production, in particular to a production process of nitrile rubber. Background technique [0002] Nitrile rubber is produced by emulsion polymerization of butadiene and acrylonitrile. Nitrile rubber is mainly produced by low-temperature emulsion polymerization. It has excellent oil resistance, high wear resistance, good heat resistance and strong adhesion. . The production technology of existing nitrile rubber has the following problems: [0003] 1. In the production process of nitrile rubber, the Mooney of the rubber is to reach the expected value. After the Mooney deviation is adjusted, the adjustment result is measured in time. Therefore, the molecular weight regulator is added at two points. The first point is the initial addition amount, and the second The second point is the supplementary amount, and the second point is the supplementary amount. When adding, the molecular weight modifier i...

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Problems solved by technology

[0003] 1. In the production process of nitrile rubber, the Mooney of the rubber is to reach the expected value. After the Mooney deviation is adjusted, the adjustment result is measured in time. Therefore, the molecular weight regulator is added at two points. The first point is the initial addition amount, and the second The second point is the supplementary amount, and the second point is the supplementary amount. When adding, the molecular weight modifier is added as the stock solution. The amount added is relatively small, and a small metering pump is used to meter it. Due to the mechanical error of the metering pump, the amount of molecular weight regulator added is not large. Steady, making Mooney difficult to control

[0004] 2. Pinane hydroperoxide, the initiator used in the polymerization reaction of the nitrile rubber production process, is added by using a small flow metering pump to meter and add the pinane hydrogen peroxide stock solution. Because the metering pump itself will produce mechanical errors during the working process, In addition, the error caused by the small amount of pinane hydroperoxide stock solution will be magnified, and the amount of initiator added will fluctuate, which will affect the polymerization reaction.

[0005] 3. In the production process of nitrile rubber, after the polymerization conversion rate reaches the design value and adding a terminator to terminate the reaction, it enters three degassing towers for degassing in turn to remove unreacted butadiene and acrylonitrile monomers, and nitrile Rubber latex contains a large amount of soap liquid, which will generate a lot of foam during the degassing process. Improper control will lead to a pulping accident in the degassing tower. The method of adding defoamer needs to use a large amount of defoamer, and too much defoamer entering the latex will cause adverse effects such as reduced tensile strength and increased vulcanization time of the finished rubber.

[0007] 5. The traditional method of nitrile rubber production uses initiators, activators, butadiene, acrylonitrile, emulsifiers, molecular weight regulators, etc. to be added at the header of the polymerization station at one time, and the mixed materials are heat exchanged after adding at the header. Cooling of the heat exchanger, due to the polymerization reaction of butadiene and acrylonitrile after adding the initiator, latex is produced, and the latex is bonded in the tube side of the heat exchanger, causing the heat exchanger to often block

Fe is used as an activator in the production of nitrile rubber 2+ complexes, due to Fe 2+ Reductive, poor stability, easy to oxidize to Fe 3+ , making the activator ineffective

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