The liquid silicone rubber injection molding method that started in the 1970s has gradually become popular, and is now recognized as a molding method for silicone rubber. First, the commonly used LIMS method will be described.

If you use one sentence to explain LIMS (Liquid Silicone Rubber Injection Molding), it is a method of pumping addition-curable liquid silicone rubber into the injection molding machine and curing it in the mold. Judging from the differences in the process flow and curing reaction of these two methods, LIMS has several advantages:

(1) Save manpower:
The process of material conveying, metering, mixing, injection and so on realizes continuous automation and reduces power consumption.

(2) Can improve production efficiency:
Shorten the molding cycle by rapid curing.

(3) Can improve product quality:
No reaction by-products are generated, and no impurities are mixed.

(4) Suitable for composite molding:
Due to the good fluidity of the material, low molding pressure, and wide curing temperature range, composite molding can be performed in addition to insert molding.

The Latest Technical Trends of LIMS
At present, not only is the transition from the simple mixing type with the above-mentioned advantages to the LIMS method, but it is also actively developing in the following two directions recently.

01 Fully automatic molding: no flash, no runner, automatic demoulding
Regarding the fully automated molding process, people have conducted research from various aspects such as injection machines, molds, and materials. It not only saves manpower in the process operation, but also reduces the cost of materials because it does not produce useless cured products, and it is also attracting attention from the perspective of environmental protection. For the molding of miniature products such as skeleton oil seals for automobiles, the molding cycle (from injection to the next injection) is required to be within 10s, which can be completed in a very short time.

02 Composite molding: Insert molding, binary molding
Because the form of crosslinking reaction is addition curing, it can be molded at a relatively low temperature. Since no by-products such as peroxide decomposition residues are generated during the crosslinking reaction, there is no need for secondary vulcanization in principle. Therefore, it can be integrally molded with resin, molded by coating primer material, and dual molding that makes the sealing part and the skeleton part a whole has also begun to be popularized.

Silicone rubber has excellent properties (heat resistance, plug resistance, weather resistance, electrical insulation, flame retardancy, etc.). Due to these properties, it is possible to make environmentally friendly molding based on fully automatic molding, and integral molding with metals and organic resins. In addition, the material itself is transparent and colorable, so its application scope involves many fields, such as (computer, mobile phone, etc.) keys, milk bottle nipples, (copiers, printers, etc.) rubber rollers, pipe joint seals, oil seals And other auto parts, TV picture tube anode caps, diving supplies, etc.