First of all, we need to understand what is the vulcanization of rubber parts.
Vulcanization refers to the production of rubber materials (raw rubber, plasticized rubber, mixed rubber) with certain plasticity and viscosity after appropriate processing (such as calendering, extrusion, molding, etc.) The finished semi-finished product is re-transformed into soft elastic rubber parts or hard rubber parts through the action of chemical factors (such as vulcanization system) or physical factors (such as gamma rays) under certain external conditions, so as to obtain the process of using performance.
During the vulcanization process, external conditions (such as heating or radiation) cause a chemical reaction between the raw rubber and the vulcanizing agent or between the raw rubber and the raw rubber in the rubber composition, and the linear rubber macromolecules are cross-linked into a three-dimensional network. Through this reaction, the properties of rubber are greatly improved, so that rubber products can obtain physical and mechanical properties and other properties that can meet the needs of product use. The essence of vulcanization is crosslinking, that is, the process of converting the linear rubber molecular structure into a spatial network structure.
Common rubber parts production process
The common production processes of rubber parts include injection molding, hot pressing molding, extrusion molding, etc., but some rubber parts need to go through a step after they are produced, which is called secondary vulcanization, also known as two-stage vulcanization. In fact, the molded The product, we can see with the naked eye that it is basically a finished product that can be used directly. Why do we need to perform secondary vulcanization? Linde Polymer reveals the answer for you.
Not all rubber parts require secondary vulcanization
It needs to be judged according to the formula of raw materials. The properties of rubber parts produced by different formulas are different. Some can be used directly after one molding, but some are special raw materials. Made of, for example, fluorine rubber parts and some EPDM rubber parts need to be vulcanized in two stages. Because when these materials are vulcanized once, the peroxide inside will decompose and react with polymers to produce some low-molecular compounds (such as benzene, benzoic acid, etc.), and these low-molecular compounds are mixed in the rubber and will affect the mechanical properties of rubber parts. performance, so that the service life is reduced, so it is necessary to carry out two-stage vulcanization to decompose and volatilize low molecular compounds.
The benefits of vulcanization of rubber parts
- In addition, after the primary vulcanization is completed, the rubber molecules may not be fully cross-linked (insufficient vulcanization), and the second-stage vulcanization can vulcanize more fully and more uniformly, which can improve the mechanical properties and durability of the rubber.
- Two-stage vulcanization can also remove rubber odor. For example, EPDM rubber products widely used in automobiles can improve the comfort of automobiles after removing odors.
- Finally, in order to reduce costs and increase production capacity, rubber parts manufacturers often shorten the time of primary vulcanization, and then extend the time of secondary vulcanization to ensure that the product is fully vulcanized, and it is also a way to improve their own competitiveness.
About us
The above is Linde Polymer’s answer to the question of why rubber parts are subjected to secondary vulcanization. If you have other questions about rubber parts, please feel free to consult. Our company mainly produces various rubber compounds and rubber seals. Currently, we have more than 3,000 material formulas and more than 2,000 specifications of products. The products are suitable for automobile, aviation, machinery, petrochemical, sanitary, medical, food, electronics, national defense, military, industrial and other fields. Since the establishment of the factory, the company has completed the consistent operation of the manufacturing process, and the yield rate of the product manufacturing process has reached 97.1%.
