Conventional vulcanization (CV) refers to a vulcanization system of a range of normal sulfur in the range of diene rubber, which can produce a soft, highly elastic vulcanizate. The CV system of various rubbers is as follows
|Sulphur||2.5||2. 0||1. 5||2.0||1.5|
|ZnO||5.0||5. 0||5. 0||3. 0||5. 0|
|Stearic acid||2. 0||2. 0||1. 0||2. 0||1. 0|
|NS||0. 6||1. 0||—||—||—|
|DM||—||—||1. 0||0. 5||—|
|TMTD||—||—||0. 1||1. 0||1. 5|
Due to the structure of various rubbers such as unsaturation and composition, the amount of sulfur in the CV system, the variety and amount of accelerators are different. The NR has a high degree of unsaturation, and the non-rubber component in the composition promotes vulcanization, so that the amount of the accelerator is small and the vulcanization rate is fast. For HR, EPDM, etc. with extremely low unsaturation, high-efficiency and rapid accelerators such as TMTD, TRA, ZDC, etc. should be used together as the main accelerator, and thiazoles are the secondary accelerators.
When the amount of sulfur is constant, the amount of the accelerator is increased, the vulcanization induction period is unchanged, but the vulcanization rate is increased.
For the ordinary sulfur vulcanization system (CV) of NR, the amount of the general accelerator is 0.5 to 0.6 parts, and the amount of sulfur is 2.5 parts.
More than 70% of the vulcanized rubber network obtained by the ordinary sulfur vulcanization system is a polysulfide cross-linking bond, which has a relatively strong main chain modification. Vulcanized rubber has good initial fatigue properties, and has excellent dynamic and static properties at room temperature. The biggest disadvantage is that it does not heat oxidative aging, and vulcanized rubber cannot be used for a long time at higher temperatures.