First, the purpose of TPE material oil filling and the main reasons for oil production

In the processing of TPE materials, oil filling is a key process, which can effectively reduce the viscosity of SBS and make it easier to plasticize. It is worth noting that there is an inverse relationship between oil content and the hardness of TPE: high oil content leads to low hardness. Due to the good compatibility between SBS and oil, they can form a stable mixture, but this mixture is mainly based on physical action and does not occur chemical combination. Therefore, in the course of a long time of use, it is inevitable that the oil gradually oozes from the material.

SEBS as the core component of TPE, its oil absorption plays a vital role in preventing oil seepage. In the proper ratio of oil, SEBS and oil can build a stable system, thus effectively preventing oil seepage. In the actual production process, in order to reduce costs, low hardness TPE is sometimes mixed with PP, PE and other plastics, increasing the risk of oil production. The oil problem mainly stems from the blending of SEBS with newly added PE, PP, EVA and other plastics. These plastics form a rubber and plastic blend system with SEBS, but they do not have oil absorption, which reduces the overall oil absorption capacity, resulting in oil leakage. In TPE products, the oil leakage problem of high-multiple oil filled products is particularly serious.

Second, how to produce more oil filled but not easy to produce oil TPE/TPR material

The key lies in fine control of its production process and formula. Here are some concrete suggestions.

First of all, when pursuing the smoothness of products, priority should be given to the use of paraffin oil, because paraffin oil is better than naphthenic oil in the feel smoothness. In addition, the choice of star or large molecular weight SBS/SEBS is also key, because they have a higher oil filling capacity, can achieve a better oil filling effect at the same amount of oil. At the same time, adding a proper amount of smoothing agent or anti-sticking agent can further enhance the smoothness of the product.

During the filling process, it is essential to maintain proper rotation or stir-frying. Standing oil filling may result in TPE/TPR caking and uneven oil filling. Especially when the amount of oil is high, the number of revolutions should be properly reduced, because the high speed may cause the oil in SEBS/SBS to seep out, which is similar to the drying principle of the washing machine. After filling the oil, it is recommended to place the material for a period of time to allow the oil to be fully absorbed by SEBS/SBS, which can reduce the phenomenon of oil seepage during production.