1. According to the capacity of the mixing chamber of the internal mixer and the appropriate filling factor (0.6-0.7), calculate the amount of one-time mixing and the actual formula;
2. According to the actual formula, accurately weigh the amount of various raw materials in the formula, and add raw rubber, small materials (ZnO, SA, accelerator, antioxidant, solid softener, etc.), reinforcing agent or filler, and liquid softener. , Sulphur are placed separately and arranged in order on the shelf;
3. Turn on the power switch and heating switch of the mixer, preheat the mixer, and at the same time check whether the air pressure, water pressure, and voltage meet the process requirements, and check whether the temperature measurement system, timing device, and power system indications and records are normal;
4. After the mixer is preheated, stabilize for a period of time and prepare for rubber mixing;
5. Lift the top bolt, put the raw rubber that has been cut into small pieces into the mixer from the feeding port, drop the top bolt, and mix the rubber for 1min;
6. Lift the top bolt, add small material, drop the top bolt and mix for 1.5min;
7. Lift the top bolt, add carbon black or filler, drop the top bolt and mix for 3 minutes;
8. Lift the top bolt, add liquid softener, drop the top bolt and mix for 1.5min;
9. For degumming, measure the temperature of the rubber compound with a thermocouple thermometer, record the initial temperature of the mixing chamber, the temperature of the mixing chamber and the temperature of degumming at the end of mixing, the maximum power and the rotational speed of the rotor;
10. Adjust the roll distance of the open mill to 3.8mm, turn on the power switch, make the mill run, open the circulating water valve, and then throw the rubber material discharged from the internal mixer to the open mill to wrap the rolls, wait for the rubber material When the temperature drops below 110°C, add sulfur, and cut the left and right knives twice. When all the sulfur is eaten, the surface of the rubber is relatively smooth, and the rubber is cut.
11. Adjust the roll distance of the open mill to 0.5mm, put in the rubber compound, make a triangular bag, and make a thin pass 5 times, adjust the roll distance to about 2.4mm, put in the rubber roll, and wait until the surface is smooth and no bubbles. Weigh the total mass of the rubber compound, put it on a flat and clean metal surface and cool it to room temperature, put a label on it to indicate the compound formula number and mixing date, and park it for later use.
The mixing process test report of each batch of the internal mixer should record: the temperature at the start of mixing, mixing time, rotor speed, top bolt pressure, discharge temperature, power consumption, and the difference between the quality of the mixed rubber and the total quality of the raw materials and mixer type.
Note: When starting the mixing experiment, you can mix a compound with the same formula as the test compound first to adjust the working state of the internal mixer, and then formally mix; for the same batch of mixed rubber, the control conditions of the internal mixer and The mixing time should remain the same.
