RTV-2 liquid silicone curing by silicone mix with a catalyst according to the ratio. and the quantity of catalyst will affect pot lifetime, curing time and hardness after curing. Then what will happen when silicone mix with different ratio catalysts?
In general, curing time will be short with high temperatures. so should add catalyst according to the temperature. if add too much catalyst, the silicone molds will become hard and brittle. conversely, if add too little catalyst, pot lifetime will be longer than before. But when pouring molds, must add a little catalyst, so that can make perfect molds according to long curing time.
The ratio of silicone and catalyst at room temperature is as below:
1. with 1% catalyst, the silicone also is liquid when mixed after 2.5hrs, de-mold time about 6-8 hrs.
2. with 2% catalyst, the silicone also is liquid when mixed after 50-60mins, de-mold time about 2-3 hrs.
3. with 3% catalyst, the silicone also is liquid when mixed after 10-15mins, de-mold time about 1-1.5hrs.
The ratio of catalysts with different temperatures is as below:
1. The silicone will not cure after mixing with catalyst when the temperature is below 5℃.
2. The ratio of catalyst can’t be more than 5% when the temperature is about 10℃.
3. the ratio of catalyst should be 2%-3% when the temperature is about 25℃.
4. The ratio of catalyst can be 1% when the temperature is about 38-45℃.
So we can conclude that the ratio of catalyst can’t be less than 1%, otherwise, the silicone will not be cured for a long time. also can’t be more than 5%, because it will affect the hardness, tear strength and tensile strength of silicone.it is best with 2%-3% catalyst and mixing at the temperature of about 30℃.
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