Introduction to Liquid Silicone Injection Molding Process

With the development and progress of science and technology, people's understanding of the mechanism of addition reaction and the theory of silicone rubber reinforcement has deepened. By using highly reinforced white carbon black with surface hydrophobic treatment, adding a high proportion of reinforcement fillers, adopting centralized cross-linking and chain expansion technologies, not only has the mechanical strength of added liquid silicone rubber been greatly improved, reaching the level of mixed silicone rubber.

In addition, with the improvement of the performance and automation level of liquid injection molding machines, liquid injection molding silicone rubber is widely used to prepare lightweight and high-yield products, such as maternal and infant products, pacifiers, television anode caps, rubber parts for automotive machinery, rubber parts for electronic appliances, medical care rubber parts, copier rubber rollers, and various sealing washers.

Liquid silicone product processing equipment includes silicone injection machines and press machines. Its raw material is water thick and consists of two components: A and B. Its principle is to use a press to evenly mix the raw materials of components A and B in a suitable proportion, and then press them into the material barrel of the injection machine for mixing. Then, press them into the hot mold cavity through the nozzle for molding.

So what are the advantages of liquid injection molding silicone rubber technology compared to traditional thermal vulcanization technology?

Advantages: The process molding temperature is relatively low, ranging from 90 to 140 ℃. It can be used for both high-temperature resistant metal materials and less high-temperature resistant plastic packaging molding, which has advantages over solid-state hot pressing molding. High yield and easy to automate production.

1、 Liquid silicone rubber has low viscosity and can be pumped, achieving continuous and automated measurement, mixing, and injection molding processes. It can also shape various complex shapes and structures of products.

2、 The vulcanization speed is fast and can be completed in one go within 20-30 seconds. The molding cycle does not exceed 1 minute, which not only saves energy and manpower, but also improves production efficiency.

3、 Low molding pressure, accurate measurement, high mold accuracy, no burrs or defects in the product, saving raw materials and eliminating post-processing procedures.

4、 The performance of the product can be comparable to that of hot vulcanized rubber, but the production cost has been reduced by 50%. Liquid injection molded silicone rubber is usually provided to users in the form of A and B component packaging. When in use, only the A and B components need to be mixed evenly by equal volume or mass to enter the injection molding machine and formed into products under heating and pressure. In order to ensure accurate measurement of materials, when preparing components A and B, the viscosity and relative density of the two should be basically consistent. Additive liquid silicone rubber suitable for liquid injection molding has significant differences in its vulcanization characteristics and physical properties compared to potting adhesives, fiber optic coatings, and chip contact coatings.

Disadvantage: The cost of raw materials is several times higher than that of solid silicone materials.