Due to its good air tightness, butyl rubber has a place in the production of inner tube products. Nowadays, more high airtight rubber products companies choose butyl regenerated rubber (based on waste butyl inner tube as the raw material) as the main raw material. The purpose is to reduce costs. Rubber products made from butyl reclaimed rubber have high airtightness, good water-tightness, shock absorption, insulation, and chemical resistance, but they need to be improved in terms of aging. How can this be solved?
Taking butyl regenerated rubber inner tube as an example, after aging, the hardness of the product is reduced, the gum is softened, and the airtightness is reduced. The phenomenon of air leakage occurs. The aging of the butyl regenerated rubber used in automobiles will cause potential safety hazards and seriously affect the use of the product. Performance and life, how to solve the anti-aging problem in the use of butyl inner tubes.
In fact, all rubber products, including butyl regenerated rubber inner tubes, will have different degrees of aging within a limited period of time. There are many factors that cause aging, and the speed of aging will be accelerated if there is more contact:
1, ozone
Ozone is the most important factor causing the aging of rubber products. Its chemical activity is much higher than oxygen and its destructive power is also greater. Ozone not only breaks the rubber molecular chains, but also acts differently on rubber as the rubber deforms. When it acts on unsaturated rubber, cracks that are in the same direction as the stress, that is, "ozone cracking," occur; no cracking occurs when the rubber is deformed, and only an oxide film is formed on the surface.
2, oxygen
Oxygen undergoes radical chain-reaction with rubber molecules in the rubber, and molecular chains break or crosslink excessively, causing changes in rubber properties. Oxidation is one of the important causes of rubber aging, so special attention must be paid to the prevention of oxidation in the production of butyl regenerated rubber inner tubes.
3, light wave
The shorter the light wave, the greater the energy. High-energy ultraviolet rays have great destructive effects on rubber. It will not only directly cause the breakage and cross-linking of the rubber molecular chains, but also cause the rubber to produce free radicals. A network crack appears on the surface of the rubber, which is called "outer layer cracking."
In addition, raising the temperature will cause thermal oxygen aging - thermal cracking and thermal crosslinking of the rubber; soaking the rubber in moist air or water will decompose water-soluble substances and hydrophilic groups in the rubber, destroy the rubber, and so on.
At present, the methods for preventing aging of rubber products include physical protection methods and chemical protection methods. Physical methods generally use rubber-plastic blends, surface coatings or pseudo-light shielding agents, and paraffin waxes to avoid the interaction of rubber and various aging factors; chemical protection The rule refers to the active addition of amines (such as phenylenediamine, naphthylamine) or phenolic chemical antioxidants to prevent or delay the aging reaction.
Butyl inner tube can be used to delay the aging of the product by adding a small amount of EPDM rubber or EPDM reclaimed rubber. This is because EPDM rubber has good anti-aging properties, which can improve the service performance of butyl inner tube and prolong its service life. In order to ensure the airtightness of the butyl regenerated rubber inner tube, the amount of the EPDM reclaimed rubber should not be too much. Generally, the amount of the EPDM reclaimed rubber in the butyl inner tube is about 10-15 parts.
About other types of reclaimed rubber products aging methods, and butyl reclaimed rubber anti-aging methods are almost the same, Xiao Bian will not be listed one by one!
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