The quality factors affecting the filling effect of nano-calcium carbonate in rubber mainly include the following six aspects. If it is not appropriate, you are welcome to criticize and correct:
First, crystal form
Among the different types of nano-calcium carbonate, the chain-locked nano-calcium carbonate has the best reinforcing effect on rubber.
Second, the particle size
80-120nm is suitable, the application of nano-calcium carbonate in rubber, the finer the particles, the larger the specific surface area infiltrated with the rubber, so that the dispersion of calcium carbonate particles becomes more and more difficult, especially when the surface is below 80nm, due to the surface The increase in energy is likely to cause heat generation during rubber mixing and cause sticking.
Third, the surface treatment
Choose a suitable co-dispersant to enhance blending and dispersion.
Fourth, the oil absorption value
The higher the oil absorption value of the nano calcium carbonate for rubber, the better the infiltration and reinforcement of the calcium carbonate to the rubber.
As a filler for rubber, when the moisture content of the nano calcium carbonate is lowered, the scorch time of vulcanization is shortened, which is advantageous for increasing the vulcanization speed, and is generally required to be less than 0.5%.
Sixth, PH value
The effect of the pH of nano-CaCO3 in rubber applications is mainly due to its vulcanization rate. Generally, the pH value of the nano calcium carbonate is 9-10.5. If the pH value is too low, the vulcanization rate is slow and the scorch time is long, thereby prolonging the processing time and increasing the energy consumption.