Introduction
There are many thermoplastic elastomers (TPE) available in today’s marketplace. All are elastic and melt processable. Most can be processed on extrusion or molding equipment, and can be colored and fabricated by a variety of methods.
With more than 30 years of commercial product development, one thermoplastic elastomer clearly stands out for its ability to provide a multitude of physical property combinations for a wide variety of processing applications: thermoplastic polyurethane (TPU).
About TPU
TPU is a polyurethane elastomer that is fully thermoplastic. It is a linear segmented block copolymer composed of hard and soft segments. The hard segment can be either aromatic or aliphatic in nature. Aromatic TPUs are based on isocyanates such as MDI. Aliphatic TPUs are based on isocyanates such as H12MDI. When these isocyanates are combined with various short chain diols they become the hard block. Normally it is aromatic, but where color and clarity retention during exposure to sunlight is a priority, an aliphatic hard segment is typically recommended.
The soft segment can be either polyether or polyester type. The choice affects the relative suitability for a given application. For use in wet environments, for example, a polyether-based TPU is preferred. When oil and hydrocarbon resistance are primary factors, a polyester-based TPU is the material of choice. Another polyester type, polycaprolactone, also provides oil and hydrocarbon resistance with improved hydrolytic stability. A wide variety of property combinations can be achieved by varying the molecular weight of the hard and soft segments, their ratio and chemical type. For example, shore hardness ranges from 60A to 80D can be achieved. TPU also offers high tensile strength, elongation and tear resistance as compared to other TPEs.
TPU Product Information
TPU excels in offering a wide and effective combination of physical properties and attributes over a range of hardnesses.
TPUs offer:
- High elasticity
- High resiliency
- Excellent low temperature performance
- Good compressions set
- Flexibility without plasticizers
- Abrasion resistance
Plus
- Impact resistance (Toughness)
- Tear resistance
- Weather resistance
- Hydrocarbon resistance (Polyester type)
- Hydrolytic resistance (Polyether type)
- Optical clarity (Aliphatic type)
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