Influence of mixing process of rubber mixer on rubber products

Raw rubber mixing is an indispensable process in the production process of rubber products. Generally, a rubber mixer is used to knead the raw rubber, so that the rubber and various compounding agents are fully mixed and dispersed evenly. The following is a brief introduction to the influence of the mixing process on rubber products.

Here is the list

• Feeding order

• Ordinary carbon black absorption softener

• For highly filled, high viscosity rubbers

  
  

Feeding order

Feeding sequence, the mixing and feeding sequence of the rubber mixer is generally to add raw rubber first, then add accelerators, dispersants, antioxidants, etc., and then add reinforcing agents, fillers, softeners, and vulcanizing agents in turn. This is very common. The feeding sequence can be adjusted according to the actual situation.

Ordinary carbon black absorption softener

When the hardness of the compound is low, when the filling amount of the softener is equal to that of carbon black, if carbon black is added first and then oil is added, the compound will slip, making the subsequent oil-feeding process slow, mixing difficult, and The performance of the rubber mixer is related. Because the current does not go up, the open mill shows that the rubber compound is broken and the mixing efficiency is reduced, so it is necessary to use ordinary carbon black to absorb the softener and then put it into the rubber compound.

When a large amount of filler is mixed into the rubber mixing machine, the filler dust will fly and cause losses. For coarser carbon black and filler processes, all fillers, carbon blacks, oils and compounding agents can be added to the rubber mixture first. Add about 70% of the raw rubber to the mill, mix for 1-2 minutes, then add the remaining raw rubber at the end; for more reinforced carbon black and fine particle formulations, half of the oil and all fillers can be put into the mill In the glue machine, add raw rubber and mix for 2 to 3 minutes, then add the remaining oil into the rubber compound three times.

For highly filled, high viscosity rubbers

For high-filled and high-viscosity rubber, the raw rubber needs to be uniformly masticated with a rubber mixer first, otherwise the latter filler cannot be completely mixed into the raw rubber. After the raw rubber is uniformly masticated in the rubber mixer, the temperature is adjusted to about 100 degrees Celsius. At this time, the plasticity of the rubber compound is good. Then add small material, reinforcing agent, inorganic filler and softener in sequence. After mixing, you need to pay attention to parking for a period of time (about 8 hours). It is kneaded again and a vulcanizing agent is added to produce flakes.

The shear strength of the rubber mixer needs to simulate the batch production state when researching the formula with a small rubber mixer in the laboratory. ) × rotor diameter (small) ÷ 2 / gap between rotor and mixing chamber (small) = rotor speed (large) × rotor diameter (large) ÷ 2 / gap between rotor and mixing chamber (large), such as a mass-produced rubber mixer The speed of 60rpm is required, so the test mixer needs to pass 60×598÷12.5×5÷60=239.2, so the test mixer needs to be close to 240rpm. Shear strength.

Select the shape of the mixer rotor. Rotors commonly used in rubber mixers include shear rotors and meshing rotors. The shear rotor has fast feeding and high mixing efficiency, but the rotor gap is large, the shear force is also small, and the heat dissipation is small. The power is low; the meshing rotor feeds slowly, and the mixing efficiency is low, but the space between the rotors is small, the shearing force is large, the mixing is more uniform, the heat dissipation efficiency is high, and the temperature of the rubber compound is relatively high. Easy to control.

The above is the influence of the mixing process of the rubber mixer on the rubber products. For more rubber and plastic mixing knowledge, please continue to pay attention to Seahawk Machinery.