It is caused by cracks or cracks in the material that rapidly expand and crack when they are stressed, resulting in damage.
Tear strength of various rubbers (vulcanized rubber):
Natural rubber NR> Polyester thermoplastic elastomer> Isoprene rubber IR> Polyurethane rubber PUR> Chlorohydrin rubber CO> Butadiene rubber NBR> Butyl rubber IIR> Neoprene CR> Chlorosulfonated polyethylene CSM> SBS thermoplastic elastomer Body> Butadiene rubber BR> Styrene butadiene rubber SBR> Ethylene propylene rubber EPDM> Fluorine rubber FKM> Silicon rubber Q> Acrylic rubber ACM
Relationship between tear strength and vulcanization system:
The relationship between tear strength and crosslink density has a maximum value.Generally, as the crosslink density increases, the tear strength increases, and a maximum value appears; then, as the crosslink density increases, the tear strength decreases sharply. Similar to tensile strength, but the crosslink density of the best tear strength is lower than the crosslink density of the best tensile strength.
* The traditional vulcanization system of sulfur-accelerator should be used, and the amount of sulfur is 2.0-3.0 parts.
* Accelerators are selected from varieties with medium activity and good flatness, such as DM, CZ, etc.
* In natural rubber, if an effective vulcanization system is used instead of the ordinary vulcanization system, the tear strength is significantly reduced, but the effect of excessive sulfur is not significant.

Relationship between tear strength and filling system:
* With the decrease of carbon black particle size, the tear strength increases.
* Carbon black with a low degree of structure is beneficial to increase the tear strength.
* Increasing the amount of high wear-resistant carbon black in natural rubber can increase the tear strength.
* Increase the amount of high wear-resistant carbon black in styrene-butadiene rubber (60-70 parts), the maximum value will appear, and then it will gradually decrease.
* Generally, synthetic rubber, especially butyl rubber, can significantly improve tear strength when reinforced with carbon black.
* Using isotropic reinforcing fillers, such as carbon black, white carbon black, white Yanhua, Lide powder and zinc oxide, etc., can obtain higher tear strength.
* When using anisotropic reinforcing fillers, such as clay, magnesium carbonate, etc., higher tear strength cannot be obtained.
* Certain coupling agent modified inorganic fillers, such as calcium carbonate modified with carboxylated polybutadiene CPB, aluminum hydroxide, can also improve the tear strength of styrene-butadiene rubber.

Effect of softening system on tear strength
* Usually adding a softening agent will reduce the tear strength of the vulcanizate, especially paraffin oil is extremely unfavorable to the styrene-butadiene rubber vulcanizate. The aromatic hydrogen oil can ensure the tear strength of styrene-butadiene rubber vulcanizate.
* When using petroleum-based softeners as softeners for NBR and neoprene, high aromatic hydrogen oils with an aromatic hydrogen content of more than 50-60% should be used, and paraffin oil cannot be used.