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Causes of wall adhesion in the reactor
Oct 25, 2020

First, the raw material factors for urea sulfate content is too high, when in the late stage of polycondensation reaction of resin to join urea, is equivalent to join the firming agent, resin fast couplet net structure, if handled not in time, can make resin curing in reaction kettle, therefore, should be chosen in the production of standard industrial raw material, urea in the urea sulfate content restrictions under 0.01%.


Second, the degree of balance of the operation when the temperature, pressure and other rubber processing indicators control instability or fluctuation is too large, resin polycondensation process uneven, easy to cause wall adhesion. Therefore, in the production operation, should be slow pressure, temperature. Generally, about 0.15mpa of water vapor is injected and kept for 2 ~ 3min, then the pressure is slowly lifted and the temperature is raised. The lifting speed should be 0.1 ~ 0.15mpa per minute.


Third, the temperature of the cooling medium is too low or suddenly drops, so that the temperature difference between the kettle wall and the material is too large, resulting in the glue liquid touching the stainless steel reaction kettle wall sticking to the wall. Therefore, both heating and cooling should be carried out within a reasonable range of temperature difference. Generally, the steam service temperature should be less than 180℃, the thermal impact of temperature difference should be less than 120℃, and the cooling impact should be less than 90℃. At the same time, attention should be paid to determine the appropriate cooling medium inlet and outlet temperature, maintain balance operation.


When the temperature of the reaction solution is lower than 80℃, if ammonia chloride is used as the catalyst, the PH value cannot be displayed due to the fast reaction speed of ammonia chloride. After the temperature rises, the PH value will drop rapidly and the reaction speed will be accelerated. The condensation reaction is too intense, resulting in gel adhesion and wall adhesion. In addition, the polycondensation reaction time is too long, the molecular weight of the resin is large, the viscosity is too high also easy to appear wall adhesion phenomenon. Therefore, the temperature and time of the polycondensation reaction should be controlled correctly and the reaction should be terminated in time. Generally, the temperature of the reaction solution should be controlled within ~ 95℃.

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