After the TPE/TPR material is processed into a product, it sometimes appears that the product is spilt out of oil (surface sticky or even directly smear a layer of oil onto the hand). According to the different materials' compounding system, there may be two different factors. The analysis is as follows:
1.TPE|/TPR compounding system (lower hardness 0~20A) oil absorption problem
The general SEBS-based TPE|TPR has superior oil-absorption (sorption ratio) compared to SBS-based TPR. In terms of SEBS, SEBS grades with different physical properties (such as butadiene content and molecular chain structure) have different oil absorption and oil lock properties. The choice of SEBS, especially the SEBS grade with good oil lock, and the selection of the appropriate category of operating oil, will reduce the TPE, especially the lower hardness (usually lower hardness TPE material will be equipped with a larger proportion of operating oil, the chance of oil precipitation Large) TPE material surface oil problem.
2.Precipitation of TPE/TPR compounding system (higher hardness above 90A)
Higher hardness TPE, especially SEPE based system TPE, due to the relative decrease in the content of rubber SEBS in the compounding system, which leads to a small amount of oil absorption of TPE compounds, if the oil added to the compounding system exceeds a certain limit, It is easy to figure it out. For some large, thin, high-hardness TPE products, this surface oiling problem is more likely to occur.
In short, TPE/TPR products surface oil, basically TPE, TPR material problems, with the user's production and processing process is not related. In terms of materials, there are the following three aspects
First, SBS, SEBS substrate and characteristics;
The second is the category and characteristics of the operating oil;
The third is the process control of the TPE/TPR granulation process.