Learn about the production of fluorosilicone!

The reason for the dead material in the mixing of fluororubber is that the ingredient rubber comes into contact with sulfur or sulfur-containing products. Many companies do not have a dedicated fluororubber refining machine. Often, after refining other sulfur-containing rubber materials, the cleaning is not in place, or the ingredients are accidentally contaminated with sulfur or water, which can combine with the accelerator in the fluororubber to cause scorch, or the fluororubber surface is activated and decomposed due to the action of water. The solution is best to use a dedicated machine. If this is not possible, the baffle and the material tray should be thoroughly cleaned before switching to refining fluororubber, and absolutely avoid contact with water and sulfur. Special tools should be used for mixing, one spoon for each material to prevent cross contamination. Calcium hydroxide and magnesium oxide should be kept sealed and mixed as needed.

2 The sticking roller phenomenon is mainly caused by the rubber material being tightly wrapped around the rear roller or the front and rear rollers at the same time during the mixing process on the open mill, causing the former rubber material to be unable to be turned over, and the latter making the added compounding agent easy to be pressed into flakes and fall off, resulting in uneven dispersion. The main reason for the fluororubber to stick to the roller is that the fluororubber has low Mooney or too much low molecular weight. The solution to this problem is to choose raw rubber with a Mooney viscosity of about 70 when selecting the rubber, and at the same time choose raw rubber with a narrow molecular weight distribution, and then add a small amount of Brazilian wax or fluoro wax, or low molecular weight polyethylene to the formula, which can also solve the problem of sticking to the roller.

3 White spots appear in the mixed rubber This is because some powder materials of the fluororubber compound are unevenly dispersed, or the powder materials are damp and granulated, such as acid absorbers calcium hydroxide, magnesium oxide, diatomaceous earth, barium sulfate, etc. The solution is to prevent the compound from getting damp and strengthen the thin-pass process.

4 The reason why the product is easy to tear may be that the burrs are too thick, tearing during trimming, or the mold is too tight, and the burrs are stuck in the mold when demolding, which is easy to tear between the product and the burrs. The force is uneven when demolding, and the product is easy to tear. Sometimes the mold cavity is rough, or the rubber sticks to the mold, and it is difficult to demold when demolding after vulcanization, which makes the product easy to tear. In addition, if the vulcanization temperature is too high, the product will become brittle and easy to tear. For the above abnormalities, the following can be solved: the mold processing accuracy should be well controlled, the cavity roughness Ra should be less than 0.8, the matching clearance should not be too large, the vulcanization temperature should be controlled between 170 degrees, and the rubber material should be weighed accurately.