What is TPU?
Thermoplastic polyurethane (TPU) is unique categoryof plastic created when a polyaddition reaction occurs between a diisocyanateand one or more diols.
First developed in 1937, this versatile polymer issoft and processable when heated, hard when cooled and capable of being reprocessedmultiple times without losing structural integrity.
There are three main chemical classes of TPU:polyester, polyether and a smaller class known as polycaprolactone.
Polyester TPUs are compatible with PVC and otherpolar plastics. Offering value in the form of enhanced properties they areunaffected by oils and chemicals, provide excellent abrasion resistance, offera good balance of physical properties and are perfect for use in polyblends.
Polyether TPUs are slightly lower in specificgravity than polyester and polycaprolactone grades. They offer low temperatureflexibility and good abrasion and tear resilience. They are also durableagainst microbial attack and provide excellent hydrolysis resistance – makingthem suitable for applications where water is a consideration.
Polycaprolactone TPUs have the inherent toughnessand resistance of polyester-based TPUs combined with low temperatureperformance and a relatively high resistance to hydrolysis. They are an idealraw material for hydraulic and pneumatic seals.
TPUs can also be subdivided into aromatic andaliphatic varieties:
Aromatic TPUs based on isocyanates like MDI areworkhorse products and can be used in applications that require flexibility, strengthand toughness.
Aliphatic TPUs based on isocyanates like H12MDI,HDI and IPDI are light stable and offer excellent optical clarity. They arecommonly employed in automotive interior and exterior applications and aslaminating films to bond glass and polycarbonate together in the glazingindustry. They are also used in projects where attributes like optical clarity,adhesion and surface protection are required.