1. Demolding ability
The quality of demolding is an important performance of mixed rubber in molding processing. If demolding is poor, it can easily cause waste, reduce labor efficiency, pollute the mold, and increase costs. The reasons for mixing adhesive to stick or absorb molds include: firstly, the hydroxyl groups in the adhesive material react chemically with the hydroxyl groups on the metal surface of the mold at high temperatures; The second reason is that there are many low molecular weight compounds and reaction groups in the rubber material, but the internal crosslinking is not sufficient. The measures to improve demolding performance not only include adding internal demolding agents and other coordination agents, but also need to pay attention to controlling the amount of hydroxyl silicone oil added, reducing the content of hydroxyl and oligomers in the raw rubber, and paying attention to strengthening vacuum mixing and appropriately extending the mixing time.

2. Yellowing degeneration
When making transparent or semi transparent products, blended rubber sometimes experiences yellowing, especially after secondary vulcanization, where yellowing becomes more pronounced. The reasons for yellowing include: firstly, white carbon black may contain impurities and undergo oxidation at high temperatures, resulting in yellowing; Second, the residual Trimethylamine in the raw rubber is oxidized to chromogenic genes; Thirdly, the decomposition of peroxides may also produce yellow substances. In order to overcome yellowing, attention should be paid to selecting white carbon black that is not prone to yellowing, adding anti yellowing agents such as hydrogen containing silicone oil to the blend formula, and finally selecting anti yellowing vulcanizing agents to play an anti yellowing role.

3. Storage stability
As a commodity, the storage stability of mixed rubber is very important. If it exceeds the deadline, structural phenomena will occur, leading to poor processing performance. The main reason for the formation of structure is the hydroxyl groups on the surface of white carbon black in the rubber compound. Therefore, studying the performance, quality, and dosage of structural control agents is an important aspect of improving the storage life of rubber blends; Strengthening the internal mixing process, extending the vacuum mixing time, and improving the return mixing effect are all the main measures to improve storage stability.

4. Bubble problem
Extrusion is an important processing process for rubber blends, but if not properly handled, bubbles can easily occur during the extrusion process. Main reasons: Firstly, precipitated white carbon black is used as a reinforcing filler, which has a high water content (5% -8%) and is difficult to remove during production. Moreover, it is easy to absorb water after being made into mixed rubber; The second is that the rubber material brings in moist air during the return refining process; The third reason is that the air brought in during the extrusion process of the rubber material was not discharged in a timely manner. To solve the problem of extruded rubber bubbles (especially in winter), various measures need to be taken, such as using some special structural control agents to better react with the hydroxyl groups in white carbon black; At the same time, strengthen the internal mixing process, try to extract moisture and low molecular weight substances from the rubber material, and appropriately increase the plasticity value of the rubber material to better discharge bubbles during processing.