When people talk about silicone rubber, the type of elastic material that often comes to mind is dense, flexible, and heat-resistant. However, within the silicone rubber family, there is another equally dazzling but lighter member - foamed liquid silicone rubber. It combines the inherent advantage of easy processing of liquid silicone rubber with the acquired endowment of lightweight insulation of foam materials, and has sparked a quiet material revolution in cutting-edge fields such as new energy vehicles, 5G communications, aerospace, and medical health.

Foamed liquid silicone rubber, as the name suggests, is a new type of silicone rubber material that uses liquid silicone rubber as the matrix and introduces a large number of tiny pores through chemical or physical foaming, thereby obtaining low density, high resilience, and excellent thermal and sound insulation properties. Compared with the traditional solid silicone rubber foaming process, its biggest advantage lies in "liquid forming" - because the substrate itself is liquid, it can be injected into any complex cavity through precision molds like injection molding, without the tedious process of opening and closing molds. Sulfurization and foaming can be completed synchronously in the same set of molds, which not only greatly shortens the production cycle, but also makes it possible to manufacture foam parts with fine reinforcement, thin walls, and irregular structures. For application scenarios that require high-precision dimensional control, such as automotive seals, electronic product cushioning pads, and wearable device liners, this process advantage is almost irreplaceable.

From the perspective of foaming mechanism, foamed liquid silicone rubber can be mainly divided into two technical routes. One method is additive foaming, which involves adding a chemical foaming agent to a platinum catalyzed addition vulcanization system. The foaming agent decomposes and releases gases such as nitrogen or carbon dioxide at the vulcanization temperature, expanding into bubbles before the rubber material is fully crosslinked. Subsequently, the vulcanization reaction permanently fixes the pore structure of the bubbles.

The advantage of this method is that the pores are uniform and delicate, and the density can be controlled within a wide range, usually ranging from 0.2 to 0.9 grams per cubic centimeter, or even lower. Another method is injection physical foaming, similar to micro foaming injection molding technology, which injects supercritical nitrogen or carbon dioxide into liquid silicone rubber under high pressure, rapidly reduces pressure inside the mold to nucleate and expand the gas, and then rapidly cools and solidifies. This method does not require chemical foaming agents, so there is no residual foaming agent that affects the material properties. It is particularly suitable for medical devices and food contact products that require extremely high cleanliness and biocompatibility.

Regarding liquid silicone rubber, please refer to our website for details: IOTA Liquid Silicone Rubber