Thermoplastic Elastomers TPE Olefinic Type TEO

Thermoplastic elastomers contain sequences of hard and soft repeating units in the polymer chain. Elastic recovery occurs when the hard segments act to pull back the more soft and rubbery segments. Cross-linking is not required. The six generic classes of TPEs are, in order of increasing cost and performance, styrene block copolymers, polyolefin blends, elastomeric alloys, thermoplastic urethanes, thermoplastic copolyesters, and thermoplastic polyamides. 

The family of thermoplastic olefins (TEO) are simple blends of a rubbery polymer (such as EPDM or NBR) with a thermoplastic such as PP or PVC. Each polymer will have its own phase, and the rubber phase will have little or no cross-linking (that is, vulcanization). The polymer present in the larger amount will usually be the continuous phase, and the thermoplastic is favored because of its lower viscosity. The discontinuous phase should have a smaller particle size for the best performance of the TEO. EPDM rubber and PP are the constituents of the most common TEOs. Blends of NBR and PVC are also significant but less common in Europe and North America than in Japan. 

TEOs are similar to thermoset rubbers because they can be compounded with a variety of the same additives and fillers to meet specific applications. 

These additives include carbon black, plasticizers, antioxidants, and fillers, all that tend to concentrate in the soft rubber phase of the TEO. 

TPEs possess good resistance to sun and ozone and have excellent weatherability. Their water resistance is excellent, showing essentially no property changes after prolonged exposure to water at elevated temperatures. 

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