Liquid Silicone Rubber is a non-toxic, heat-resistant and highly resilient flexible thermosetting material, whose rheological behavior is characterized by low viscosity, rapid curing, shear dilution and high coefficient of thermal expansion.
Liquid silica gel is a double liquid rapid vulcanization material with platinum as catalyst, which can be produced by injection molding, large quantity, rapid vulcanization and repeatable machinery.
Its products show good thermal stability, cold resistance, excellent electrical insulation performance, combustion will not produce toxic substances.Therefore, it has become an irreplaceable material in the production and design of health products, automobiles, baby products, medical supplies, diving supplies, kitchen utensils and seals.
Due to the LSR's high expansion coefficient, it expands when heated and shrinks slightly when cooled, so the parts cannot maintain accurate side spacing in the die.Therefore, cold runner processing can be adopted, and LSR should maintain low temperature and fluidity. The cold runner uses a closed system. In the injection cycle, the closed system uses "sealing needle" or "needle valve" in each runner to control the accurate measurement of LSR materials.
Because the silicone rubber has remarkable thermal expansion characteristics, the shrinkage rate is 2 ~ 4% (vulcanization temperature is 150℃), at the same time, the silicone rubber has the characteristics of compression deformation.
Analysis of liquid silica gel flow/vulcanization:
1. The vulcanization chemical reaction of liquid silicone rubber requires a certain reaction time.
2. Ideal flow, in the diameter of 2mm, 4250px, flow distance more than 2500px.
3. The small thickness is 1/1000mm
4 mold temperature is too high will lead to vulcanization, resulting in flow obstruction.
5. Laminar flow can avoid bubbles
6. High-speed injections can cause turbulence
7. The viscosity of the material will change the flow pattern
8. Turbulence causes white spots.
Liquid silica gel in addition to some of the above characteristics, there are other characteristics, here will not be repeated one by one, if you want to know more about this related knowledge, welcome to pay attention to our new best.
