HYDEX® 4101 Rod, Double Annealed

HYDEX® 4101 is an unfilled PBT polyester supplied as machinable rod and plate. It behaves like a tougher, more forgiving PET: tensile strength around 9,400 psi, tensile modulus about 430,000 psi, flexural modulus near 430,000 psi, Rockwell M87 hardness and roughly 50% elongation at break, so it takes bending and handling abuse that would crack a more brittle polyester. Water absorption is about 0.02% in 24 hours, a small fraction of what nylon takes on, which is why machined parts hold size in wet and washdown service. Dynamic coefficient of friction is about 0.25 and it wears well unlubricated.

It is used heavily in food and beverage processing and packaging machinery, for filler parts, star wheels, timing screws, guide rails, wear strips, bushings and change parts, and in pharmaceutical, cleanroom, semiconductor, conveyor and automotive equipment. Resistance to chlorinated sanitisers and to caustic and acidic cleaners is the main reason it displaces acetal on washdown lines. Long-term service temperature is about 221°F, heat deflection is 200°F at 264 psi and 310°F at 66 psi, flammability is UL94 HB, and the material is capable of FDA food-contact compliance. It machines and polishes easily with low tool wear. Avoid prolonged hot water or steam, where hydrolysis attacks polyester.