When using butyl reclaimed rubber to produce low-cost rubber products, the selection of appropriate accelerators can not only significantly reduce the vulcanization temperature, shorten the vulcanization time, improve the production efficiency, but also improve the tensile strength, wear resistance, aging resistance and other physical properties of the vulcanized rubber, and improve the safety of the processing process. Different accelerators have different activation temperature and activation energy, and the vulcanization rate can be controlled to meet different process requirements through reasonable matching.
1. Thalam accelerators
Chiuram accelerators are mostly used as the main accelerators in the vulcanization system of butyl reclaimed rubber products, and the main varieties are accelerators TMTD, TETD, TMTM, DPTT, etc., among which the accelerator TMTD is the most commonly used. The accelerator TMTD vulcanization initiates quickly, and is often used in combination with accelerator M, accelerator DM or dithiocarbamate, and the dosage is generally controlled within 1.5 parts.
(1) With the combination of sulfur-accelerator TMTD, the heat resistance of butyl reclaimed rubber vulcanized rubber is poor, and vulcanization reversion may occur after long-term vulcanization. (2) Sulfur donor, TMTD-DTDM system vulcanization, butyl reclaimed rubber vulcanized rubber has good heat resistance and low compression set. (3) The combination of thiuram accelerator and zinc dithiophosphate has low heat generation, high fixing stress and small compression set.
2. Dithiocarbamate
Dithiocarbamate accelerator is an ultra-speed accelerator, as the main accelerator of the sulfur vulcanization system of butyl reclaimed rubber, the structure is similar to that of thiuram accelerator, with greater activity, fast vulcanization speed and high cross-linking, but it is easy to burn, poor flatness, easy to under-sulfur or oversulfur, and the main varieties are accelerators PZ, EZ, PX, TDEC, etc.
(1) The accelerator TDEC-DM is used in combination, the dosage of DM is about 1.5 parts and the amount of sulfur is appropriately reduced, which can improve the problem of easy scorching of TDEC, and the heat aging resistance of butyl reclaimed rubber vulcanized rubber is excellent. (2) Selenium dithiocarbamate is used in combination with accelerator DM, and the vulcanization activity of butyl reclaimed rubber vulcanized rubber is very high. (3) Dithiocarbamate E4LYY45 used in combination with dithiophosphate accelerator can improve the tensile stress and tensile strength of butyl reclaimed rubber vulcanized rubber, reduce hysteresis loss and permanent deformation. (4) It is recommended to choose zinc dithiocarbamate (PZ) or use it in combination with the accelerator TMTD/M.
3. Thiazole accelerators
Thiazole accelerators are mostly used as auxiliary accelerators in the sulfur vulcanization system of butyl reclaimed rubber, and the main varieties are accelerators M and DM, which are mainly used to improve the activity of the main accelerator and improve the scorching safety of butyl reclaimed rubber vulcanized rubber. The dosage of accelerator M/DM is generally among 0.5-1 parts, and after more than 1.5 parts, the tensile stress and tensile strength of the reclaimed rubber vulcanized rubber will be reduced.
The role of accelerator in butyl reclaimed rubber products is multifaceted, and different varieties of vulcanization accelerator have different effects in butyl reclaimed rubber. The rational use of accelerators can also improve the fluidity and plasticity of the rubber compound, which is convenient for molding and processing; Improve the stability of the rubber compound during storage and processing, and prevent the early vulcanization of the rubber material; In some applications, accelerators can improve the adhesion of rubber to other materials.
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