29. Why are the physical and mechanical properties of the compound inconsistent?
Matching agent weighing is not allowed, mainly reinforcing agent, vulcanizing agent and accelerator omission and mismatch, will seriously affect the physical and mechanical properties of the rubber compound after vulcanization. Secondly, such as mixing time is too long, the order of dosing is unreasonable, uneven mixing, can also cause the physical and mechanical properties of the rubber vulcanization after unqualified. Measures to strengthen the first fine work, the implementation of the three inspection system to prevent misallocation and omission of materials.

30. Why the rubber will produce burnt
There are several reasons for the scorching of rubber: irrational design of formula, such as too much vulcanizing agent and accelerator; too large capacity of rubber loading and improper operation of rubber refining.

31. How to prevent the rubber from burning
Preventing scorching is mainly to take measures according to the causes of scorching.
(1) Prevent burning, such as strict control of mixing temperature, especially the sulfur temperature, improve the cooling conditions, according to the order of the process specification charging, strengthen the management of rubber, etc..
(2) Adjust the vulcanization system in the formula, and add anti-scorch agent appropriately. 32.

32. Why should we add 1-1.5 % stearic acid or oil to deal with heavily scorched rubber?
For the general degree of coke less rubber, in the open refiner on the thin pass (roll pitch 1-1.5mm, roll temperature below 45 ℃) 4-6 times, parked for 24 hours, mixed into the good material to use. The mixing amount should be controlled below 20%.

33. Why should the rubber be stored on the iron plate?
Plastic, mixed rubber is very soft, if put on the ground, gravel, dirt, wood chips and other debris easy to stick in the rubber, not easy to be found, mixed into the quality of the products will be seriously reduced, especially for some thin products is more fatal, if the metal debris into the mixing, will cause accidents in machinery and equipment. Therefore, the rubber must be stored in the special iron plate, according to the designated location.

34. Why does the plasticity of the rubber compound change a lot sometimes?
The plasticity of the rubber mixing changes, many factors affecting the main factors are: (1) plasticizing rubber sampling is not uniform; (2) mixing plasticizing rubber pressurization is not appropriate; (3) the number of incorrect softeners; (4) changes in the raw materials, especially the changes in the raw rubber and carbon black to solve the above problems is the main measure is the strict implementation of the process procedures, pay attention to the raw material changes in the technical notification at any time.

35. Why should the mixing rubber be thin through the refining after discharge from the refiner?
The temperature of the rubber discharged from the refiner is generally above 125℃, and the temperature of sulfur should be below 100℃, in order to quickly reduce the temperature of the rubber, so it is necessary to repeatedly invert the rubber, and then add sulfur, add accelerator operations.

36. What should be paid attention to in the process of using insoluble sulfur rubber?
Insoluble sulfur is unstable and can be converted to soluble sulfur in general. The conversion is slow at room temperature, but accelerates as the temperature rises, and can be converted to ordinary sulfur within 10-20 minutes at temperatures above 110 °C. Therefore, this type of sulfur should be processed at the lowest possible temperature. Therefore, this kind of sulfur should be stored at the lowest possible temperature. In the batching process, we should also be careful to maintain a low temperature (below 100 ℃) to prevent its transformation into ordinary sulfur. Insoluble sulfur is often difficult to disperse uniformly due to its insolubility in rubber, and due attention should also be paid to this in the process. Insoluble sulfur is only used to replace the general soluble sulfur, does not change the vulcanization process and the performance of vulcanized rubber. Therefore, there is no point in using it if the process temperature is too high or if it is stored for a long time at higher temperatures.

37. Why sodium oleate used in film cooling units should be circulated
Sodium oleate, the isolating agent used in the cold water tank of the film cooling unit, does not serve the purpose of cooling the film due to the fact that the film coming down from the press continuously retains heat in the sodium oleate, causing its temperature to rise rapidly. In order to reduce its temperature, it is necessary to carry out circulating cooling, and only in this way can the cooling and isolating effects of the film cooling unit be more effectively utilized.

38. Why mechanical hobbing is better than electric hobbing for film cooling devices?
At the beginning of the film cooling device had tried electric hob, the structure is complicated, maintenance is difficult, the knife mouth at the rubber is easy to early vulcanization, unsafe, and then changed to mechanical hob, maintenance is convenient, to ensure product quality and safe production.