There are several possible reasons why rubber may become encapsulated during the manufacturing process:

1. The thickness of the rubber material is too thin and the KEY can cover the air and prevent it from being discharged.
2. The vulcanizing agent and powder are unevenly dispersed or the rubber material has expired.
3. The number of exhausts is not enough or the exhaust distance is not set.
4. Pressurization is too fast or the mold temperature is too low or the vulcanization time

To avoid the problem of wind encapsulation in rubber, the following measures can be taken:

Modify the thickness of the rubber material
By adjusting the thickness of the rubber material, the air in the mold cavity can be easily discharged during the molding process, reducing the likelihood of air entrapment.

Re-mix the rubber material
If the air entrapment issue is due to uneven mixing of the rubber material and additives, re-mixing the material thoroughly can help ensure a more uniform dispersion and reduce the presence of air pockets.

Adjust the exhaust times or exhaust distance
Increasing the number of exhaust times or adjusting the exhaust distance during the molding process allows for better release of trapped air and helps achieve a more uniform rubber product.

Extend the up and down stop time or increase mold temperature
By extending the up and down stop time or increasing the mold temperature, the rubber material can flow more easily, allowing trapped air to escape and reducing the occurrence of air entrapment.

Increase the amount of additives appropriately
Adjusting the amount of additives, such as anti-foaming agents or release agents, can help reduce the formation.