Thermoplastic Elastomers (TPE) Molds
Thermoplastic elastomers (TPEs) have two big advantages over the conventional thermo set (vulcanized) types -- processing ease and speed. Other compelling reasons for considering the TPEs are recyclability of scrap, lower energy costs for processing, and the availability of standard, uniform grades (not available in thermo sets). The TPEs are molded or extruded on standard plastics-processing equipment in considerably shorter cycle times than those required for compression or transfer molding of conventional rubbers.
Olefins: Thermoplastic olefin (TPO) elastomers are available in several grades, having room-temperature hardnesses ranging from 60 Shore A to 60 Shore D. These elastomers remain flexible down to -60°F and are not brittle at -90°F. They are autoclavable and can be used at service temperatures as high as 275°F in air. The TPO's have good resistance to some acids, most bases, many organic materials.
Thermoplastic vulcanizates (TPV) are essentially a fine dispersion of highly vulcanized rubber in a continuous phase of a polyolefin. Critical to the properties of a TPV are the degree of vulcanization of the rubber and the fineness of its dispersion. The cross linking and fine dispersion of the rubber phase gives a TPV high tensile strength (1,100 to 3,900 psi), high elongation (375 to 600%), resistance to compression and tension set, oil resistance, and resistance to flex fatigue. TPVs have excellent resistance to attack by polar fluids and fair-to-good resistance to hydrocarbon fluids. Maximum service temperature is 275°F.