Formula design

1. Raw gum

The selection of raw rubber mainly needs to consider the curing speed of stiffness and fluidity

Stiffness: in order to achieve the required stiffness, the rubber material will not be deformed due to its own weight pressure during the vulcanization process. The raw rubber shall be of the higher brand of Mooney.

Fluidity: In order to achieve the fluidity required for extrusion, the lower brand of Mooney should be considered when selecting raw rubber

Vulcanization speed: Because the vulcanization speed of foamed rubber is usually faster, in order to meet the need of vulcanization speed, the brand with higher content of the third monomer shall be used when selecting raw rubber.

In combination with various factors: we must choose according to the wall thickness and size of the hose. Generally, raw rubber with higher Mooney is selected. It can also be mixed with high bottom Menni.

2. Reinforcing agent

Generally, we choose carbon black with good fluidity for the sake of the fluidity of rubber compound

3. Vulcanization system

The curing system of silicone foam hose is usually required to be fast. A lot of hyperstimulation and hyperstimulation must be used. TDEC (TL) is the best. The speed is fast and the scorch is short. Its disadvantage is that it is not safe to store. In order to make the decomposed gas easier to foam the rubber, we also pay attention to the crosslinking density when designing the curing system. Too high crosslinking density is not conducive to foaming. For example, reducing the amount of sulfur is a better method.

4. Foaming agent

When selecting foaming agent, attention should be paid to the foaming starting temperature and maximum temperature of foaming agent.

The decomposition temperature of foaming agent is too low: it is easy to cause foaming to precede vulcanization, which is not conducive to the smooth and clean surface of rubber hose. The decomposition temperature of foaming agent is too high: it is easy to cause vulcanization after foaming, which is not conducive to the smooth foaming of rubber hose.