The butyl reclaimed rubber is a reclaimed rubber produced from waste butyl inner tube. It has excellent water tightness, heat resistance, ozone resistance, aging resistance, corrosion resistance, sound absorption and shock absorption, and is widely used for high airtightness of inner tubes. In the production of rubber products, shock-absorbing materials, protective equipment and other rubber products, butyl raw rubber is used to reduce the raw material cost of rubber products. Among them, the choice of butyl regenerated rubber vulcanization system has an important influence on the performance of butyl regenerated rubber products.
The vulcanization system of rubber is generally composed of a vulcanizing agent, an activator, and an accelerator, as well as a butyl regenerated rubber. Common butyl regenerated rubber vulcanization systems include sulfur vulcanization systems and resin vulcanization systems. The performance of butyl regenerated rubber compounds vulcanized with different vulcanization systems differs:
1. Butyl reclaimed rubber sulfur curing system
The butyl regenerated rubber sulfur curing system uses sulfur as the main vulcanizing agent. The greater the amount of sulfur, the lower the tensile strength and the elongation at break of reclaimed rubber. When the vulcanization temperature reaches 140°C, the elongation at break and the tensile strength are the maximum when 100 parts of butyl regenerated rubber is added with 1.5 parts of sulfur.
In the butyl regenerated rubber sulfur curing system, the most common accelerators are accelerator M and accelerator TMTD, accelerator M is an acid accelerator, and the curing speed is medium. The accelerator TMTD is a typical representative of thiuram accelerators: When 0.5 part of accelerator M and 0.5 part of accelerator TMTD are added, the tensile strength of butyl regenerated rubber can be effectively increased; the amount is too large (more than 1.5 parts of accelerator M and more than 0.5 parts of TMTD accelerator), and the tensile strength of reclaimed rubber products Significantly lower. Therefore, the amount of sulfur in the butyl regenerated rubber curing system must be reasonably controlled.
In the butyl regenerated rubber vulcanization system, the role of the activator is to activate the entire vulcanization system, accelerate the vulcanization speed, shorten the vulcanization time, promote the cracking of the rubber, and increase the plasticity of the butyl regenerated rubber. The common activators are DPDS, 420/950/980, etc. The rubber product manufacturers choose the appropriate activator according to their own needs to determine the dosage. In addition, zinc oxide, which is widely used in rubber products, can also be used as an activator in the butyl regenerated rubber vulcanization system to activate the vulcanization system, strengthen the vulcanization process, increase the vulcanization efficiency, and improve the corrosion resistance of the butyl regenerated rubber products. , abrasion resistance and tear strength and other properties, usually 100 parts of butyl reclaimed rubber is best to add 5 parts of zinc oxide, both to improve the rubber processing technology and product performance, without affecting the quality of butyl reclaimed rubber products.
2, resin curing system
For butyl regenerated rubber products, especially for the curing system of rubber products produced by the combination of butyl reclaimed rubber and butyl rubber, the regenerated rubber products obtained by the resin curing system have better performance; compared with the traditional sulfur curing systems The cross-linking density of vulcanizates in the resin vulcanization system has been significantly improved. This is because when the resin is vulcanized, a certain number of double bonds are required in the rubber backbone of the butyl regenerated rubber to form a “Thomas ring” with the resin first, and a three-dimensional crosslinked network is formed, although the butyl regenerated rubber contains C=C few double bonds, but it can still form a cross-linked network with the resin. Among them, in the vulcanization system composed of phenolic resin and tin chloride, the increase in the amount of tin chloride can improve the vulcanization performance of the butyl regenerated rubber.
Sulfur vulcanization system and resin vulcanization system vulcanized butyl reclaimed rubber have their respective advantages and disadvantages. Rubber product manufacturers need to select the appropriate vulcanization system for vulcanization according to the performance requirements of butyl regenerated rubber products.
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