The main reason of the "self sulfur" in the process of placing the rubber mixing material in the closed rubber mixing machine:
(1) the use of vulcanizing agent, accelerator too much;
(2) large capacity, high temperature, high temperature, film cooling;
(3) or early with sulfur, spices dispersion caused by uneven local concentration of sulfur and accelerator;
(4) improper parking, that is, the temperature of the parking place is too high, the air does not flow, etc..
Rubber Mooney how to reduce?
Rubber Mooney M (1 + 4), which is at 100 degrees 1 minutes warm-up, 4 minutes of rotor torque, which is hindering the rotation of the rotor force. Who can reduce the rotor turning force can reduce the Mooney, raw materials including raw rubber, natural rubber and synthetic rubber, natural rubber Mooney choose low or adding chemical peptizer to natural rubber formulation (physical plasticizer effect is not good) is a good choice, generally do not add synthetic rubber peptizer, usually you can add some low-fat molecular weight than the so-called dispersing agent or release agent such as the strict requirements on the hardness, then of course, can also increase the stearic acid or oil component; if in the process, can increase the pressure or increasing the discharge temperature, if the condition allows reducing the temperature of cooling water can also reduce rubber mixing rubber mooney.
Factors influencing the mixing effect of the closed rubber mixing machine
The mixer and open rubber mixing machine compared with the mixing time is short, high efficiency, high degree of automation, mechanization glue, good quality, low labor intensity, safe operation, small loss, environmental advantages of flying medicine health condition is good, but the mixer mixing cooling difficulties of mixing chamber, mixing the temperature is high and difficult to control, the restrictions on compound temperature sensitive, not suitable for light colored rubber and rubber mixing varieties varied frequently. In addition, the mixer needs to be equipped with the corresponding lower plate device.
(1) filling capacity
A reasonable amount of glue should be able to ensure that the rubber in the mixing chamber of the largest friction and shear action, so that the mixture evenly dispersed. The amount of glue is determined according to the characteristics of the equipment and the material properties. Generally, according to the total volume and fill factor, the filling coefficient is 0. 55 to 0. 75. Such as the use of equipment for a long time, due to the internal insulation of the chamber, the filling coefficient of a large value, the amount of glue can be increased. As the top bolt pressure, or plastic material plasticity, can also increase the amount of glue.
(2) jacking pressure
Increase the pressure, not only can increase adhesive capacity, but also can make faster and more effectively contact each other and extrusion between the parts and equipment between rubber and rubber, with the accelerating agent into rubber process, so as to shorten the mixing time, improve production efficiency, but also can reduce the material in contact with the sliding surface equipment the increase of rubber shearing stress, improve the matching degree of dispersion agent, improve the quality of the rubber. Therefore, at present, many measures are taken to increase the diameter of the top bolt or increase the air pressure to improve the mixing efficiency and mixing quality.
(3) rotor speed and rotor structure
In the process of mixing, the shear rate of rubber is proportional to the rotor speed. Increasing the shear rate of the rubber can shorten the mixing time, which is the main measure to improve the efficiency of the mixer. At present, the mixer speed is from 20 min to 40 R / R / min, 60R / min, up to 80 R / min, the dark smelting cycle from 12 to 15 min reduced to a minimum of L ~ L. 5 min. In recent years, in order to meet the requirements of the mixing process, has been used in multi speed or variable speed mixer mixing, according to the characteristics of the rubber and process requirements, change the speed at any time, in order to achieve the best mixing effect. The structure shape of the mixer rotor has a great influence on the mixing process. The elliptical rotor of the mixer is increased from two to four, which can play a more effective role in shearing and stirring. The production efficiency can be increased from 25 to 30%, and the energy consumption can be reduced. In recent years, in addition to the oval, as well as the triangular, cylindrical rotor shape of the mixer in the production of application.
(4) mixing temperature
In the mixing process of the mixer, the heat is large and the heat dissipation is difficult. By mixing temperature at 100 ~ 130 C biogas Wai, also adopted 170 ~ 190 C high temperature I Kunming refining this process in synthetic rubber mixing had used glue temperature slow mixing when the row of general control in 125 ~ 135 C, fast mixing when the discharge temperature is up to 160. More than C. I Queensland, smelting temperature will reduce the effect of mechanical shearing rubber, the mixing unevenly, thermal oxidative degradation and exacerbate the rubber molecules, the rubber mechanical properties decreased, at the same time, but also to produce excessive chemical binding and excessive production of gel between rubber and carbon black, the the degree of rubber plastic drop, rubber surface roughness, caused by calendering and extrusion processing difficulties.
(5) dosing sequence
The rubber compound and the rubber compound should be added first, so as to form the whole. Solid softener and small medicine in addition of carbon black fillers added before, to ensure that it has sufficient mixing time. The liquid softener must be added in addition of carbon black, so as not to produce carbon black dispersion group caused difficulties; ultra accelerator and sulfur added in under the machine after cooling, or two mixing in the mixer, but the discharge temperature should be controlled at 100 "C.