Bubbles are one of the common defects in rubber products, usually manifested as a round or irregularly shaped cavity on the surface or inside the rubber product.
1.1 Reasons for the formation of bubbles
1. Uneven mixing:
In the process of rubber mixing, if the raw materials are not fully mixed, air may remain inside the rubber, leading to the formation of bubbles in the vulcanization process.
2. uneven heating:
in the vulcanization process, the mold or heating equipment temperature distribution is not uniform, which may lead to uneven heating of the rubber, thus generating air bubbles in some areas.
3. Unclean or oily moulds:
If there is residual oil or impurities on the surface of the moulds, they may react with the rubber during the vulcanization process and form air bubbles.
4. Presence of volatile substances:
Some rubber formulations contain volatile components (e.g. solvents, plasticizers, etc.), which evaporate during vulcanization and may form air bubbles.
1.2 Bubble solution
1. Improve the mixing process:
Ensure that the rubber raw materials are evenly mixed to avoid air residue inside the rubber. The use of vacuum mixing machine can effectively reduce the mixing process of air incorporation.
2. Control the vulcanization temperature:
Ensure uniform temperature distribution during the vulcanization process to avoid local overheating or overcooling. The temperature control equipment can be calibrated regularly to ensure the accuracy of temperature control.
3. Keep the mold clean:
clean the mold regularly, remove the oil and impurities on the surface, make sure the surface of the mold is smooth and pollution-free.
4. Optimize the formula design:
Minimize or avoid the use of raw materials containing volatile components, or add an appropriate amount of stabilizer in the formula to reduce the volatility of volatile substances.
