Continuous production method for vulcanization accelerator DPG

Abstract

The invention provides a continuous production method for a vulcanization accelerator DPG. The method comprises the following steps that (1) diphenylthiourea, a catalyst, ammonium hydroxide and an organic solvent are mixed to obtain a reaction raw material mixture; (2) the reaction raw material mixture and an oxidizing agent are subjected to an oxidation reaction in a continuous flow reactor to obtain a reaction product; (3) the reaction product is post-treated to obtain the vulcanization accelerator DPG, wherein the organic solvent in step (1) can dissolve the diphenylthiourea and the vulcanization accelerator DPG. The method reduces the pressure in the reaction process, improves the utilization rate of the raw materials, stabilizes the product quality, greatly shortens the reaction timecompared with a conventional technology, improves the reaction yield, and effectively overcomes the disadvantage of traditional kettle type batch production.

Description

technical field [0001] The invention belongs to the technical field of rubber accelerators, and relates to a continuous production method of a vulcanization accelerator DPG. Background technique [0002] In the process of using rubber to produce various rubber products such as tires, hoses and rubber shoes, five types of additives must be used, which are rubber vulcanization accelerators (referred to as accelerators), rubber antioxidants, rubber vulcanization and vulcanization activators, processing Type rubber additives and special functional additives. The vulcanization accelerator is called accelerator for short. Substances that promote vulcanization. It can shorten the vulcanization time, lower the vulcanization temperature, reduce the amount of vulcanizing agent and improve the physical and mechanical properties of rubber. [0003] The chemical name of the accelerator DPG is 1,3-diphenylguanidine. It is one of the important varieties of rubber vulcanization accelerat...

AI Technical Summary

Problems solved by technology

This process uses ethanol instead of water as the solvent and diluent for the reaction, and uses ammonia instead of ammonia water as the reaction raw material to avoid the generation of waste water, but in the overall reaction process, oxygen and ammonia will be fed into the reactor at the same time according to a fixed ratio. Although the solvent ethanol can dissolve part of the ammonia, but because the solubility of ammonia in ethanol is not high, there is obviously a mixed atmosphere of ammonia and oxygen within the explosion limit range in the system, which is very prone to explosion, and the process is inherently safe. Very large and does not have industrial value

Moreover, this process also requires high-temperature ethanol solution to filter and separate the product ammonium sulfate (that is, the filter cake obtained from the high-temperature filtration of the primary product), which further increases the safety risk of the overall process and makes it unsuitable for industrialization.

[0007] In addition, the current synthesis process of the accelerator DPG mainly uses tank reactors for intermittent operation, and the factors between batches are greatly affected by personnel operations, and the product quality is prone to instability.

At the same time, during the kettle oxidation process, the amount of ammonia water is large, and the unreacted ammonia and oxygen are likely to form explosive mixtures, which increases the process risk.

At the same time, the manufacturing cost of the pressure reactor is relatively high, and it is prone to problems in long-term operation