As a versatile copolyester, Hytrel® combines resilience and chemical resistance with strength and durability across a wide temperature range. Hytrel® offers significant advantages with regards to chemical resistance when compared to common competitive materials such as TPU or silicon rubber. This makes it a first-choice flexible material where contact with chemicals is likely, for example in automotive, medical, industrial and consumer applications.
Hytrel® provides excellent resistance to non-polar materials such as oils and hydraulic fluids, even at elevated temperatures. This can be even further enhanced by heat-stabilisation. With non-polar materials such as acids, bases, amines and glycols, Hytrel® provides good resistance at room temperature. Please note that Hytrel® is not suitable for applications which are exposed to polar fluids at temperatures of 70°C or above. In moist environments, the resistance of Hytrel® is good at room temperature. Its hydrolytic stability can be improved in higher temperatures by utilising Hytrel 10MS as a stabiliser. The below chart demonstrates the hydrolysis resistance of Hytrel® at higher temperatures.
Generally, the resistance of Hytrel® to fluids and chemicals increases as the hardness of the polymer increases. The hardest, stiffest Hytrel grades provide the best heat and chemical resistance, whereas the softer, more flexible Hytrel grades provide better performance in low temperature environments.
The inherent flexibility of Hytrel® means that it does not contain any plasticiser, unlike other flexible materials such as PVC, nylon and rubber compounds. When materials containing plasticiser additives come into contact with fluid or chemicals, the plasticiser can be extracted from the material, which causes a significant increase in stiffness (modulus) and volume shrinkage.
For example, a plasticised nylon of approximately 63D hardness undergoes a two-fold increase in modulus and shrinks about 10% when exposed to ASTM Oil No. 1 for 7 days at 120°C. HYTREL® shows no change in modulus and swells approximately 0.3% under the same exposure conditions.
With Hytrel®, property changes like this are completely avoided, provided a stable, high performing and stable material for your application.
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