Fluorosilicone is a good elastomer. The main chain is Si-O bond in its structure. After adding polar fluorine atoms (such as trifluoropropyl) into the side chain, the structure of fluorosilicone rubber is called CH2CH2CF3. Because of the strong electron-absorbing effect of fluorine atoms, the bond length of the C-F bond is shorter, it can form a good shielding effect to C-C bond, improve oil resistance and solvent-resistance of rubber, and make it a good elastomer with good resistance to non-polar medium at -68°C ~ 232°C. Therefore, fluorosilicone rubber is widely used in the field of the high-end locomotive and military aerospace seals.
As the price is expensive, and the electronic effect of fluorosilicone rubber, has strong adsorption to the surrounding dust, thus affecting the performance, so the production process of fluorosilicone rubber is very strict. Here is some suggestion of the production process.
Transportation and preservation. In the process of preservation and transportation, fluorosilicone rubber must be wrapped with insulating paper and plastic bags to prevent dust and impurities from contact with the rubber and adsorption.
Cutting fluorosilicone rubber. In the process of taking materials, cutting. First of all, using alcohol to scrub the surface of the knife or the tool scissors, after cleaning, can start the cutting. In the cutting process, try to avoid hand, skin, and rubber contact, but can not wear gloves, so as to avoid the pollution of glove fiber or skin oil on the fluorosilicone rubber.
Weighing fluorosilicone rubber. Before weighing, the tray needs to be cleaned with alcohol.
Fluorine silicone rubber mixing. Before mixing, must use alcohol scrub the mixer roller and baffle, to ensure no impurities contamination. When mixing, should pay attention to the roller temperature, when the roller temperature is 18 °C ~ 28 °C mixing process performance is better. If you need to add silica to adjust the hardness, you must first use hydroxyl fluorine silicone oil to pretreat the silica.
Vulcanization of fluorosilicone rubber. The mold used to produce fluoroelastomer products must be treated by surface treatment, chrome plating treatment, if necessary, use the external release agent.
Second vulcanization of fluorosilicone rubber. There is a lot of low molecular weight volatiles after the first vulcanization. Long-term use will affect the properties of the products, so the general products must be vulcanised in two stages. the second stage vulcanization is carried out in the electric heating blower, and the temperature is kept constant after the required temperature is reached by the way of step-by-step heating. For normal fluorosilicone rubber products, the temperature is 200℃ with 4 to 6 hours.
Re-mixing of fluorosilicone rubber. Long-term parking of fluorosilicone rubber easy structuralization, affect the performance, so for the use of long-term parking of rubber materials need to be re-mixing, placed in the mixer roll 25 times, mixing time of about 8 minutes, to ensure that materials mixed evenly.
Fluorosilicone rubber production environment. Because it has the characteristic of static electricity absorption ash, so the production environment needs to be purified and dust-free workshop, the production tool is the special equipment. Workers are required to wear clean clothes and hats for entry and exit operations.