Silicone oil has a crucial role in foam stabilization, acting as a nucleation agent, emulsifier, and stabilizer. As a foam stabilizer, silicone oil is a surfactant that can disperse polyurea well in the foaming system, acting as a "physical cross-linking point" and significantly increasing the early viscosity of the foam mixture to avoid foam breakage.
By increasing the mutual solubility between the various components of the foam material, silicone oil has an emulsifying effect, which enhances the quality of the foam material. Its addition to the foam material can significantly reduce the surface tension of the liquid, making gas dispersion easier. This process facilitates the generation of fine bubbles, improves the foam's cell structure and control of pore size, and enhances the foaming stability.
The amount of silicone oil needed in the foam production process varies based on the foam density and the other components in the formula, especially stannous octoate and isoester index. A higher foam density needs more silicone per hundred parts of polyether. A suitable amount enhances the foam's uniform cells, clear structure, and moderate skin thickness.
An incorrect dosage of silicone oil can lead to a collapsed or thick-skinned foam. Adding too much silicone oil makes the bubble film too elastic and strong, causing the bubble wall to remain unbroken. This issue leads to closed-cell rates increasing, less resilience, and an inappropriate amount range of tin catalyst when in mild cases. In severe cases, the foam becomes closed-cell and even shrinks.
Using the appropriate variety of silicone oil is essential based on the different product series. Choosing the right silicone oil variety is the basis for a successful foam production process. By increasing the amount of silicone oil used, the cells can become more delicate and less likely to break. This aspect creates closed cells while adding a certain degree of toughness to the foam structure.