There are two kinds of liquid silicone rubber for molds, one is condensed industrial grade mold silicone rubber, and the other is additive food grade mold silicone rubber. Condensation type industrial grade mold silicone rubber is composed of silicone rubber and curing agent, and condensation type industrial grade mold silicone rubber curing agent is organotin curing agent. Organotin curing agent mainly depends on the action of tin element inside to achieve the effect of curing silicone rubber.

At a constant temperature of 25 ℃, 2% curing agent is added to the condensed industrial mold silicone rubber. The curing time of silicone rubber is 3-4 hours. The lower the temperature, the slower the curing. Therefore, when the temperature is too low, or when the customer needs to cure the silicone rubber quickly, more curing agent should be added. Of course, the proportion of curing agent is not unlimited. There is a certain proportion control, which is generally controlled at no more than 4% - 5%. What happens when too much organotin curing agent is added?

When the organotin curing agent is added too much, the silicone rubber will solidify quickly first. When the silicone rubber is cured, the silicone rubber mold will be easy to produce oil, shrink and deform, and even the mechanical properties such as tear resistance and tensile strength will be reduced. Therefore, the addition proportion of organotin curing agent should not be too high, and must be within a reasonable range. In addition, excessive organotin curing agent can not change the hardness and hand feel of silicone rubber.

So what happens when too much platinum catalyst is added to the silicone rubber of the molding die?

The curing agent of silicone rubber in addition mold is mainly platinum catalyst, and the content and activity of platinum catalyst are very important. The activity of formed platinum catalyst will increase under the action of temperature, so as to accelerate the curing of silicone rubber. What happens if too much platinum catalyst is added to the mold rubber? First, add molding silicone rubber to cure quickly, and then add molding translucent color. After curing, silicone rubber will cure quickly. Finally, excessive platinum catalyst will lead to deviation in the hardness of silicone rubber and reduce the performance of silicone rubber. Therefore, when adding environmental friendly silicone rubber, it must be weighed with an electronic scale, and the proportion shall be stirred and used in strict accordance with the ratio of one to one.