Rubber scorching is a type of advanced vulcanization behavior, which refers to the phenomenon of early vulcanization that occurs in various processes before vulcanization (rubber refining, rubber storage, extrusion, rolling, forming). Therefore, it can also be called early vulcanization. Rubber scorching is a type of advanced vulcanization behavior, which refers to the phenomenon of early vulcanization that occurs in various processes before vulcanization (rubber refining, rubber storage, extrusion, rolling, forming). Therefore, it can also be called early vulcanization.
The reason for the occurrence of scorching phenomenon:
(1) Improper formula design, imbalanced vulcanization system configuration, and excessive use of vulcanizing agents and accelerators.
(2) For some types of rubber that need to be melted, the plasticity is not up to the requirements, the plasticity is too low, and the resin is too hard, resulting in a sharp temperature rise during the compounding process. If the roller temperature of the rubber refining machine or other roller devices (such as the return mill and rolling mill) is too high and the cooling is not enough, it may also cause on-site coking.
(3) When unloading the mixed rubber, the pieces are too thick, the heat dissipation is poor, or they are stored hastily without cooling. In addition, poor ventilation and high temperature in the warehouse can cause heat accumulation, which can also lead to coking.
(4) Poor management during the storage process of rubber materials resulted in natural burning even after the remaining burning time was used up.
The hazards of scorching:
Difficulty in processing; Affects the physical properties and surface smoothness of the product; It may even lead to disconnection at product joints and other situations.
Methods to prevent scorching:
(1) The design of the rubber material should be appropriate and reasonable, such as using multiple methods of accelerator as much as possible. Suppress scorching. To adapt to high temperature, high pressure, and high-speed rubber refining processes, an appropriate amount (0.3-0.5 parts) of anti coking agent can also be added to the formula.
(2) Strengthen the cooling measures for rubber materials in rubber refining and subsequent processes, mainly by strictly controlling machine temperature, roller temperature, and ensuring sufficient cooling water circulation, so that the operating temperature does not exceed the critical point of coking.
(3) Pay attention to the management of semi-finished rubber materials, and each batch of materials should be accompanied by a flow card. Implement the “first in, first out” storage principle, and specify the maximum storage time for each vehicle of materials, which should not be exceeded. The warehouse should have good ventilation conditions.
Post time: Apr-24-2024
