The basic formula of liquid foaming silicone rubber includes: vinyl silicone oil, foaming additives (alcohol, hydroxyl silicone oil), hydrogen-containing silicone oil, platinum catalyst, inhibitors and other components.
Vulcanization principle: After the two components AB are mixed, a cross-linking reaction occurs between vinyl silicone oil and hydrogen-containing silicone oil, and a dehydrogenation condensation reaction occurs between the foaming aid and hydrogen-containing silicone oil to generate silicone rubber foam.
Foaming aids (alcohol, hydroxyl silicone oil), hydrogenated silicone oil, platinum catalysts, inhibitors, etc. have a certain impact on the foaming process of RTV-2 liquid foaming silicone rubber and the performance of silicone rubber foam:
The higher the hydrogen content of hydrogenated silicone oil, the higher the activity, which shortens the gelling time of the rubber compound and reduces the foaming density of silicone rubber foam.
The higher activity of small alcohols makes the foaming reaction much faster than the cross-linking reaction. The released H2 overflows quickly, and the foam cells produced are larger.
The activity of hydroxyl silicone oil is slightly lower, which makes the foaming reaction and cross-linking reaction better matched, and the cells produced are fine and uniform. Therefore, hydroxyl silicone oil is more suitable as a foaming aid than small molecular alcohols.
When the dosage of hydrogen-containing silicone oil is fixed, increasing the dosage of hydroxyl silicone oil can improve the permanent compression set performance of silicone rubber foam. Changes in the dosage of catalysts and inhibitors have little effect on the performance of silicone rubber foam, but can change the operating time. The kneading process is used to process silica online to prepare base glue.
After being treated with silazane, the gelation time of the rubber compounds prepared with different silicas is accelerated to varying degrees. The viscosity-increasing effect of fumed silica is significantly higher than that of precipitated silica, and the foaming density of silicone rubber foam becomes larger.
The type of silica has little effect on the permanent compression set performance of silicone rubber foam. Silica has a complex impact on the thermal weight loss behavior of silicone rubber foam, increasing the material's residual rate.

Silicone foam IOTA-HT-800