How to Control the Hardness of TPE

With the increasingly widespread application of TPE materials, many related enterprises have emerged and established themselves both domestically and internationally in recent years. However, many people do not have a good understanding of the hardness of TPE and do not know how to control it, which has caused a lot of trouble. So, how to control the hardness of TPE? Last time, I shared the shrinkage rate of TPE. Now, the technical staff of Zhongsuwang will share with you how to control the hardness of TPE.

How to control the hardness of TPE:

1. For general TPE, hardness adjustment is done by the content of oil, PP, and calcium carbonate. Increasing the amount of PP or calcium carbonate increases the hardness, and vice versa. Adding oil reduces the hardness.

2. If the oil filling is normal but there is still oil leakage and stickiness, it indicates that the quality of the SEBS/SBS material or the oil is poor. Among all SEBS materials, Kraton has the best oil filling effect, sometimes able to fill up to 10 times its weight.

3. Oil-filled SBS/SEBS tend to turn yellow, mainly because naphthenic oil contains unsaturated double bonds that oxidize and turn yellow. Usually, domestic Karamay naphthenic oil is hydrogenated and will not cause this problem, so be careful when selecting oil.

4. Often, our products have parameters such as hardness, tensile strength, etc. Oil can only reduce hardness and tensile strength, so engineering plastics are usually added as well, such as PP is often added when making TPE. Parameters like hardness and strength can be adjusted according to the amount of PP and oil filling.

5. When filling oil, try to keep stirring or turning. If left to stand, it is easy for TPE/TPR to clump and the oil filling will be uneven. When the oil filling amount is high, the rotation speed should be reduced, as high speed can easily cause the oil already filled in SEBS/SBS to leak out (the principle is similar to that of a washing machine's spin cycle). After oil filling, it is best to let it sit for a while so that the oil is fully absorbed by the SEBS/SBS before production, otherwise, oil leakage may easily occur during production.