Difference between Polyester TPU and Polyether TPU
It’s widely known that TPU is a type of elastic plastic, which we can see them everywhere. TPU can be generally separated into two types: Polyester TPU and Polyether TPU. Of course, these two different types TPU has different features. Here we show some difference between them.
Refers to the different distribution of hard segment and soft segment, Polyester and Polyether also have difference on mechanical property. Compared with Polyether TPU, Polyester one has better performance on strength, oil resistance, thermal-oxidative stability.
TPU is easy to be affected by water molecules to get fractured. Then the acid from hydrolyzation makes polyester hydrolyze once again. It’s known to all who are in TPU industry that TPU must be dried before processing. But Polyester has worse hydrolytic stability than Polyether. This is the reason why polyester TPU has much more water content than polyether. So polyester TPU should be dried longer in a higher temperature before processing.
When polyester TPU was buried by humid soil, it would be corroded by microorganism. But in the same circumstance, polyether TPU shows better data.
There has bigger friction between molecules of Polyester TPU, then it has bigger cohesive energy, which leads to the difficulty of Polyester TPU to be refrigerated. Therefore, compared with Polyether TPU, Polyester needs longer time to cool down to solidify after processing.
Polyether TPU is more expensive than Polyester. There are several reasons. First of all, Polyether has better property on hydrolytic stability, cold resistance and bending resistance. Secondly, the poly-alcohols that form soft segment of Polyether TPU has higher price on raw materials. Thirdly, producing Polyether poly-alcohols is much more complicated and difficult than producing Polyester one. Besides, producing Polyether poly-alcohols asks for higher requirement of equipment.
In conclusion, neither for Polyester nor Polyether, they have their own strength and weakness. According to different usage, different types of TPU will be chosen.