HYDEX® 4101L is an internally lubricated polybutylene terephthalate (PBT) polyester. Its defining property is dimensional stability: water absorption is 0.07% in 24 hours, among the lowest of any machinable engineering thermoplastic, so parts cut to size stay at size regardless of ambient humidity. The lubricant package lowers friction and lifts PV capability over unmodified PBT. Mechanically it offers 7,200 psi tensile strength, 380,000 psi tensile modulus, 10,600 psi flexural strength, 10,500 psi compressive strength at 10% strain, 40% elongation, and Rockwell M75 (R115) hardness, with good resistance to fuels, oils, greases, and dilute acids.
Machined parts include fuel pump components, valve bodies and seats, gears, bushings, bearings, wear strips, and food and dairy equipment hardware. In its natural colour the material is FDA and USDA compliant and meets 3-A Dairy requirements, making it a straightforward choice for wash-down production areas. The UL 94 rating is HB. It machines cleanly, cuts sharp detail, and needs little post-machining allowance for moisture-driven movement. Maximum operating temperature is 221°F with a 195°F heat deflection temperature at 264 psi. Notched impact strength is modest at 0.7 ft-lb/in, and prolonged hot water, steam, or strong alkali exposure will hydrolyse the polyester backbone.
Internally lubricated PBT - lower friction and higher PV than unmodified PBT
Water absorption 0.07% in 24 hours, among the lowest of any machinable thermoplastic
FDA and USDA compliant in natural and meets 3-A Dairy requirements
Tensile strength 7,200 psi on a 380,000 psi tensile modulus
Rockwell M75 hardness with 40% elongation at yield
Maximum operating temperature 221°F, 195°F heat deflection at 264 psi
Resists fuels, oils, greases and dilute acids
Double annealed to relieve stress for close-tolerance machining