During the rubber mixing process using an open mill, the rubber material may be burnt for some reason. To prevent the rubber material from being burnt, a technical engineer from Lina will introduce the methods to prevent it. The detailed content is as follows:

  Firstly, it is important to reduce the dosage of vulcanization accelerators, but this can lead to a decrease in the physical properties of rubber products. Understanding this is crucial as vulcanization accelerators are rarely used alone. Once there is a problem with the dosage, it cannot prevent the rubber material from burning.

  Generally speaking, the main accelerator used for general rubber is sulfonamide accelerator, the main accelerator DM is a universal accelerator, the accelerator M has high scorch resistance, and although sulfonamide accelerator has scorch resistance, it needs to be selected according to the requirements of the rubber material due to the slow starting speed of vulcanization. Therefore, the auxiliary accelerator of the thiuram series is used. In the hot summer season, the use of auxiliary accelerators should be reduced, while the main accelerator should try not to reduce its dosage.

  Adding 10-20 parts by mass of recycled rubber to general rubber and blending it to produce a rubber compound that has the effect of preventing scorching. For the blended rubber compound, it is necessary to consider designing additive formulas and make necessary modifications based on the study of scorching and physical properties of vulcanized rubber



In combination with white carbon black adhesive, diethylene glycol, polyethylene glycol, organic amine co promoter SL, etc. should be added. However, excessive addition of these additives can also cause burning, so attention must be paid.



The standard blending amount should be 60% of diethylene glycol and polyethylene glycol (molecular weight of 400) compared to white carbon black, and 2.5% of organic amine promoter SL. Although many discussions have been made in terms of coordination as mentioned above, if it is still not possible to prevent scorching, anti scorching agents (sulfurization delay agents) can be added. Sulfurization delay agents are organic compounds such as anhydrous phthalic acid and benzoic acid, nitroso compounds, and phthalamide. Due to the polluting nature of nitrosodianiline, it cannot be used for light colored rubber products.



Anti coking agent not only delays vulcanization, but also slows down the vulcanization rate. As it reduces crosslinking degree, it should not be used in large quantities. According to the experience of Lina engineers for many years, the dosage should not exceed 0.4%. If it must exceed 0.4%, the amount of vulcanization accelerator should be reduced first. It is not advisable to use the combination method of high accelerators and high anti scorching agents.



For each batch of mixed rubber material, based on the original data, set the range of burning time and continuously adjust and solve it within this range. For example, set the Mooney burn time to 125 ℃, MS, 15-25min. The mixed rubber can be cooled to room temperature by water cooling, air cooling, or a combination of both. Even if the rubber material is rolled and coiled, if there is a risk of burning, the open mill can wind and roll it at the same time, or cut it to a certain length before air cooling. It can also be stored in air-conditioned rooms or refrigerated warehouses as needed.



For most of the rubber materials that need to be re refined, first put the rubber materials that need to be re refined into a hot mill for hot refining. After confirming that the rubber materials have not been burnt, add new rubber compound for mixing. If the operating procedure is reversed, it will cause all the rubber materials to be burnt.



How to prevent the rubber material from burning when using an open mill? The above is an introduction to techniques for preventing the burning of rubber materials.