1.3 Platinum catalyst
Platinum catalyst is the catalyst for curing and crosslinking reaction with molded silica gel. Peroxides, azo compounds, ultraviolet light and γ-rays can also be used as catalysts to promote or initiate hydrixilation reactions, but their reaction byproducts are more, so the application is less. Platinum-vinyl siloxane complex is the most widely used platinum catalyst in industry and laboratory, which has the characteristics of high catalytic efficiency and little side effects.
1.4 SiH addition inhibitors
In general, the two-component plus molded silica gel is required to operate for more than 4h at room temperature after the AB component is mixed. When the curing rate is too slow, the production efficiency will be affected. If the curing speed is too fast, it will cause premature crosslinking gel mixture, which will affect the actual packaging application. In order to ensure that the molded silica gel has a long service life, inhibitors are generally added to the mixture to obtain the appropriate operation time. At low temperature, the inhibitor and platinum catalyst can form coordination compounds to achieve inhibition effect. At high temperature, the catalyst can be reversibly released to achieve normal curing.
1.5 tackifier
As a silicone additive for methyl LED packaging, viscosifier plays an important role in promoting the bonding between silica gel and LED scaffold. Adhesifier can increase the adhesion of silica gel and LED bracket, so as to ensure that the LED lamp beads in the process of high and low temperature change, silica gel and bracket do not fall off, and ensure the LED lamp beads on the air moisture, air sulfur dioxide barrier.