Causes and solutions of bubbles generated by vulcanization of rubber products
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Causes of bubbles during vulcanization of rubber products:
1. The rubber mixing is uneven, and the operators are not standardized. According to the reasonable feeding sequence and the number of thin passes, as well as the back pressure process after parking and aging.
2. The rubber film is not parked properly and the environment is unsanitary. Management is not standardized. foreign impurities.
3. The material has moisture (add some calcium oxide when mixing)
4. The vulcanization is insufficient, and it looks like there are bubbles when it is not cooked.
5. Insufficient vulcanization pressure.
6. There are many impurities in the vulcanizing agent, the impurities of small molecules become decomposed in advance, and the bubbles remain in the product
7. The exhaust design of the mold itself is unreasonable, and the gas cannot be discharged in time when the rubber material is punched!
8. The product is too thick, the rubber material is too small, the heat transfer of the rubber is slow, and after the surface is vulcanized, the fluidity of the rubber decreases, resulting in a lack of material, so air bubbles may be generated. Adjust the vulcanization rate, and it is not easy to be too fast.
9. The exhaust gas was not discharged well during the vulcanization process. Improve the number of exhausts and the interval between exhausts.
10. For formula problems, the vulcanization system should be improved. Low temperature slow (relative) is recommended.
Solution: Improve vulcanization pressure and time
a. Extend the vulcanization time or increase the vulcanization speed. Reasonable curing temperature range.
b. Thin pass several times before vulcanization. Stop to ripen and then press back.
c. Exhaust times are a little more during vulcanization. The exhaust time interval is reasonably arranged.
d. Reduce the Mooney of the mixed rubber, and choose the rubber with low air tightness (raw rubber or formula matching reduces the air tightness).