1. When choosing rubber material, it should give consideration to gas tightness and weight loss ratio, also the vacuum degree. In general, low vacuum degree require product (eg.: vacuum pumping rubber pipe in electric bulbs factory) use natural rubber material. But for high vacuum resistant requirement rubber products, it had better use NBR with high acrylonitrile content or FPM.

2. Since high vacuum degree resistant rubber must be treated by high temperature grilling before come into service, rubber material should also be high temperature resistant, FPM or NBR is the best choice.

3. Choosing of compounding agent. Plasticizer has low volatilization point and large dose, we’d better not to use it. While anti-aging agent is easy to volatile, we also should try to not to use it.

4. In the manufacturing method of rubber joint, sphere hardness must be ensured, otherwise, it may be flatten under vacuum condition.