Causes of scorch phenomenon:

(1) Improper formula design, unbalanced vulcanization system configuration, and excessive vulcanizing agent and accelerator dosage.
(2) For some types of rubber that need to be masticated, the mastication does not meet the requirements, the plasticity is too low, and the gum is too hard, resulting in a sharp temperature rise during rubber mixing. The roll temperature of the rubber mixer or other roller devices (such as remixers, calenders) is too high and the cooling is not enough, which may also lead to scorch on site.
(3) When the rubber compound is unloaded, the film is too thick, the heat dissipation is poor, or it is not cooled, that is, it is stored in a hurry, coupled with factors such as poor ventilation in the warehouse and high temperature, which will cause heat accumulation, which will also cause scorch.
(4) The rubber compound is not properly managed during the storage process. After the remaining scorch time is used up, it is still not used, and natural scorch occurs.

Scorching Hazards:

Difficulty in processing; affect the physical properties of the product and the smoothness of the outer surface; even lead to disconnection at the joint of the product.

Ways to prevent scorch:

(1) The design of the rubber compound should be appropriate and reasonable. For example, the accelerator should be used in a variety of ways as much as possible. Scorch is suppressed. In order to adapt to the high temperature, high pressure and high speed rubber mixing process, an appropriate amount (0.3-0.5 parts) of anti-scorch agent can also be used in the formula.
(2) Strengthen the cooling measures for the rubber compound in the rubber mixing and subsequent processes, mainly by strictly controlling the machine temperature, roller temperature and ensuring sufficient cooling water circulation, so that the operating temperature does not exceed the critical point of scorch.
(3) Pay attention to the management of semi-finished rubber materials, each batch of materials should be followed by a flow card, implement the "first-in, first-out" inventory principle, and stipulate the maximum storage time for each vehicle material, which shall not be exceeded. The warehouse should have good ventilation conditions.