Three elements of rubber vulcanization (time, temperature and pressure)


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Release time:

Jul 21,2021

1, rubber products vulcanization time: at a certain temperature, molding, in order to make the rubber from plastic to elastic, and to maximize the crosslinking density, the time used to optimize the physical and mechanical properties of rubber products vulcanization time. The auxiliary time of the operation process is usually not included.

Vulcanization time is closely related to the curing temperature, in the vulcanization process, the physical and mechanical properties of vulcanized rubber to reach or close to the best point, the degree of vulcanization is called positive vulcanization or the most appropriate vulcanization. The vulcanization time required to reach positive vulcanization at a certain temperature is called positive vulcanization time, and a certain vulcanization temperature corresponds to a certain positive vulcanization time. When the compound formula and vulcanization temperature are certain, the vulcanization time determines the degree of vulcanization. Rubber products of different sizes and wall thicknesses can control the degree of vulcanization by controlling the vulcanization time. Usually, the larger or thicker the size of the product, the longer the vulcanization time is.

2、What is the vulcanization temperature

Rubber vulcanization temperature is the basic condition of rubber vulcanization reaction (crosslinking reaction), which directly affects the rubber vulcanization speed and the quality of the product. Like all chemical reactions, the vulcanization reaction is accelerated with the increase of temperature, and it is easy to generate more low-sulfur cross-linking bonds; the vulcanization temperature is low, the speed is slow, the generation efficiency is low, and more multi-sulfur cross-linking bonds are generated. The vulcanization temperature is generally applicable to Van Hoff's law, that is, for every 8 to 10 ° C (approximately equivalent to a gauge pressure of steam pressure), the reaction rate is approximately doubled; in other words, the reaction time is approximately reduced by half.

3、

Vulcanization pressure refers to the pressure on the unit area of the rubber compound during the vulcanization process. In general, in addition to some cloth pieces and sponge rubber, other rubber products need to apply a certain pressure during vulcanization.

Rubber vulcanization pressure is an important factor to ensure the geometric size, structural density, and physical machinery of rubber parts. At the same time, it can also ensure that the surface of the parts is smooth and free of defects, and meet the sealing requirements of rubber products. The main role of the following points:

  1. 1. To prevent the mixture in the vulcanization molding process to produce bubbles, improve the compactness of products;

  2. 2. Provide the power for the filling and flowing of the glue, so that the glue can fill the entire mold cavity within the specified time;

  3. 3. Improve the adhesion of rubber and clips (cord, etc.) and the bending resistance of rubber products;

  4. 4. Improve the physical and mechanical properties of rubber products.