Silicone rubber extrusion foaming product technology details!

1、 Vulcanization and foaming mechanism of foamed rubber extrusion pipe

1. Coordination of vulcanization and foaming

The curing speed should match the foaming speed. One party cannot be significantly faster than the other.

The curing speed is too fast: the foaming agent cannot be successfully decomposed due to the strong mechanical force of the vulcanizate to foam the rubber.

The curing speed is too slow: the foaming agent decomposes the gas and foams the rubber when the rubber is completely or nearly unvulcanized, but at the same time, the surface of the rubber is also broken by the gas, so that the surface of the rubber tube is uneven or has pores.

Comparison of the two speeds: generally, the curing speed needs to be slightly faster than the foaming speed, which can ensure the smoothness of the surface of the rubber hose and enable the foaming agent to decompose the gas to foam the rubber.

2. Foam process of rubber hose

Microwave: The foam of rubber hose is mainly completed by microwave heating. The rubber tube is heated from the inside to the outside by the microwave heat radiation. When the inner part of the rubber tube is just beginning to be heated and foamed, the relative temperature of the rubber material outside the rubber tube is still low, so that the rubber tube cannot be completely vulcanized. This heating method from inside to outside ensures that the rubber hose can foam smoothly.

The heating and foaming of the rubber tube by microwave is accompanied by vulcanization, but the vulcanization does not reach the final vulcanization depth at this time. After coming out of the microwave, it enters the hot air heating section to complete the final vulcanization of the rubber tube. To complete the vulcanization and foaming of rubber hose.