Natural latex reclaimed rubber has the characteristics of good elasticity and high strength, which can replace all or part of natural rubber production products and effectively reduce the cost of raw materials. When using latex reclaimed rubber to produce rubber products, a reasonable selection of vulcanization accelerator can not only effectively shorten the vulcanization time, reduce the vulcanization temperature and reduce the amount of vulcanizing agent, but also improve the physical and mechanical properties and chemical stability of natural latex reclaimed rubber vulcanized rubber. So what are the vulcanization accelerators commonly used in the production of latex reclaimed rubber products?
1. Thiazole accelerators
(1) Accelerator M: It has medium vulcanization speed and good processing safety, good vulcanization flatness, vulcanization critical temperature of 125 °C, easy to disperse in rubber, no pollution, and not easy to produce early vulcanization, and is a commonly used accelerator in the production of latex reclaimed rubber products; The latex reclaimed rubber vulcanized rubber using accelerator M in the vulcanization system has good wear resistance, tear resistance and tensile stress, and good physical properties and aging resistance.
(2) accelerator DM: the vulcanization speed is slightly slower than that of accelerator M, the scorching safety is better, the critical temperature of vulcanization is 130 °C, the activity above 140 °C increases, there is a good after-effect, it is not easy to appear early vulcanization in the processing process, and it is often used in combination with other accelerators to improve its activity. The natural reclaimed rubber vulcanized rubber with accelerator DM has good physical and mechanical properties of vulcanized rubber, such as tensile strength, tear strength and abrasion resistance, as well as good scorch resistance, and is suitable for use in a long processing time.
2. Thuram accelerators
(1) Accelerator TMTD: It is a typical rapid accelerator, with high activity, and is mostly used as an auxiliary accelerator for thiazole or hyposulfonamide accelerator in the formula of natural latex reclaimed rubber products, and the free sulfur is slowly resolved above 100 °C, so it can be used as a vulcanizing agent, and the vulcanized rubber has good aging resistance and heat resistance. It should be noted that the accelerator TMTD is easy to spray, and too much dosage or too high temperature may cause early vulcanization of rubber, which brings difficulties to processing.
(2) Accelerator TMTM: the activity is slightly lower than that of accelerator TMTD, the vulcanization speed is relatively slow, the frosting phenomenon is relatively light, and the processing safety is better, which is suitable for some latex recycled rubber products that require a long time to process, accelerate the vulcanization reaction speed, and improve the E4LYY1014 performance of vulcanized rubber; It is often used in combination with other accelerators to meet the vulcanization needs of different rubber products. The accelerator TMTM can provide a stable cross-linked structure during the vulcanization process, and the tensile strength of the vulcanized rubber has high wear resistance.
3. Sulfonamide accelerators
(1) Accelerator CZ: It has high vulcanization activity, long scorching time, good processing safety, no early vulcanization at higher processing temperature, and is suitable for high-temperature rapid vulcanization process. The accelerator CZ can endow natural latex reclaimed rubber vulcanized rubber with good comprehensive properties, especially tensile strength, tensile stress and wear resistance.
(2) Accelerator NOBS: high activity, slow vulcanization start, fast vulcanization speed, belongs to delayed fast accelerator; When the accelerator NOBS is used in the vulcanization system of latex reclaimed rubber, the vulcanized rubber has high strength and good elasticity. It should be noted that NOBS may produce nitrosamines under certain conditions during use, which has certain safety risks.
4. Dithiocarbamate accelerator
Accelerator ZDC is a medium-speed accelerator, vulcanization temperature adaptation range is wide, among 130 - 160 °C can play a good role, the vulcanization process generated cross-linked bonds are relatively stable, can effectively resist the external environmental factors (such as oxygen, ozone, etc.) on the erosion of rubber products. It can give latex reclaimed rubber vulcanized rubber better elasticity and aging resistance.
5. Guanidine accelerators
Accelerator D is a typical delayed accelerator, with a slow vulcanization rate, and is mostly used in combination with other accelerators such as thiazoles and hyposulfonamides. Accelerator D can improve the hardness, tensile stress and tensile strength of natural reclaimed rubber vulcanized rubber, but excessive dosage will lead to the decrease of elasticity and heat resistance of vulcanized rubber.
Other accelerators will also be used in the production of latex reclaimed rubber products, such as accelerators MBT and MBTS in thiazole accelerators, accelerators TETD in thiuram accelerators, accelerators CBS and DZ in sulfenamide accelerators, and so on. The specific role and dosage of different types of accelerators in latex reclaimed rubber are different, and the follow-up editor will continue to share with you the common combinations of vulcanizing agents and accelerators in the vulcanization system of latex reclaimed rubber products.
Exclusive original article [commercial authorization] reprint, excerpt and excerpt in any form are prohibited without written authorization. Focus on Hongyun rubber: learn the process formula and raw material technology of producing rubber products from recycled rubber to help you reduce costs and increase profits