what's the difference?

Question

TPU/ Soft Silicon/ Silicon Gel?

Answer 1

Thermoplastic polyurethanes (abbreviated TPU) are a class of polyurethane plastics with many useful properties, including elasticity, transparency, and resistance to oil, grease and abrasion. Technically, they are thermoplastic elastomers consisting of linear segmented block copolymers composed of hard and soft segments. TPU are formed by the reaction of: (1) diisocyanates with short-chain diols (so-called chain extenders) and (2) diisocyanates with long-chain bifunctional diols (known as polyols). The practically unlimited amount of possible combinations producible by varying the structure and/or molecular weight of the three reaction compounds allows for an enormous variety of different TPU. This allows urethane chemists to fine-tune the polymer’s structure to the desired final properties of the material. The final resin consists of linear polymeric chains in block-structures. Such chains contain low polarity segments which are rather long (called soft segments), alternating with shorter, high polarity segments (called hard segments). The crystalline or pseudo crystalline areas act as physical cross-links, which account for the high elasticity level of TPU, whereas the flexible chains will impart the elongation characteristics to the polymer.

These "pseudo crosslinks", however, disappear under the effect of heat, and thus the classical extrusion, injection moulding and calendering processing methods are applicable to these materials. Consequently, TPU scrap can be reprocessed