During the operation of the rubber internal mixer, the two rotors rotate relative to each other, and the material from the feeding port is clamped into the roll slot and subjected to the extrusion and shear of the rotor. After passing through the roll slot, the material meets the lower top fastening edge, which is divided into two parts, and then returns to the top of the roll slot along the gap between the front and rear chamber wall and the rotor. During the flow around the rotor, the material is subjected to shear and friction action everywhere, which makes the temperature of the rubber rise sharply, reduces the viscosity, increases the wettability of the rubber on the surface of the agent, and makes the rubber fully contact with the surface of the agent.
Because the shear action of the rubber in internal mixer is much greater than that in internal mixer, and the mixing temperature is higher, the mixing efficiency of mixer is much higher than that of mixer.
In addition to the order of feeding, the quality of compound in rubber internal mixer depends mainly on mixing temperature, charging capacity, rotor speed, mixing time, top fastening pressure and type of rotor.
In the mixing process of rubber internal mixer, the sequence and mixing time of raw rubber, carbon black and liquid softener are particularly important. Generally, the raw rubber is added first, followed by carbon black, and then liquid softener is added after the carbon black is basically dispersed in the rubber mixture. In this way, it is conducive to mixing, improving the mixing effect and shortening the mixing time. Liquid softener early to join or too late to join, are adverse to the smelting, is easy to cause uneven dispersion and mixing time, mixing high temperature is advantageous to the raw rubber and plastic flow and deformation of the rubber, is advantageous to the rubber of solid compound particles on the surface of the wet and mixed powder, but again lowered the viscosity of rubber, is not conducive to compound particle breakage and dispersive mixing.
Too high temperature of wet refining will also accelerate the thermal oxygen aging of rubber, so that the physical and mechanical properties of vulcanized rubber decline, that is, the phenomenon of refining; The coke burning phenomenon will also occur, so effective cooling measures must be taken in the mixing process of rubber internal mixer. But the temperature must not be too low, otherwise there will be the phenomenon of rubber compression dispersion.
Article by: [Yashi China machine supplier]-Global professional B2B export platform for cross border machinery -China Machinery Suppliers-Sorting out and publishing