Silicone rubber molds are widely used in industrial manufacturing, medical applications, and art reproduction due to their excellent resistance to high and low temperatures, aging resistance, and good elasticity. Their synthesis method primarily relies on the crosslinking reaction of liquid silicone rubber (LSR) or room temperature vulcanized silicone rubber (RTV). The core steps include raw material preparation, mixing, degassing, and curing.
First, select a suitable silicone rubber base material, typically a two-component (component A containing vinyl siloxane and component B containing hydrogen siloxane) or a single-component (pre-mixed and then room temperature vulcanized). Components A and B are mixed in appropriate proportions. The amount of catalyst added directly affects the crosslinking rate. Platinum catalysts are commonly used to promote the addition reaction of silicon-hydrogen bonds to vinyl groups. During the mixing process, environmental cleanliness must be strictly controlled to prevent impurities from affecting mold precision.
After homogeneous mixing, degassing is performed, often using vacuum degassing to eliminate bubbles introduced during mixing and ensure a smooth, defect-free mold surface. The degassed rubber is then injected into the mold cavity. Depending on the vulcanization method, either room temperature vulcanization or heated vulcanization can be used. Room temperature vulcanized silicone rubber (RTV-2) gradually cures at around 25°C under the action of a catalyst, requiring a longer curing cycle but simplifying the process. High temperature vulcanized silicone rubber (HTV) and some RTV-1 types require heating to 100-150°C to accelerate the crosslinking reaction and shorten the molding time.
After curing, the silicone rubber mold is removed from the mold. Its replica accuracy can reach ±0.05mm, making it suitable for precision casting of complex structural parts. Modern processes also incorporate fillers (such as silica) to improve mechanical strength or introduce fluorescent agents to aid quality control. Continuous optimization of silicone rubber mold synthesis technology is driving its expanded application in emerging fields such as rapid prototyping and microfluidic chips.
