Medical TPVs For Replacing Rubber In Molded O-Rings and Gaskets Provide Long-Term Seal Integrity and Lower Processing Costs

July 27, 2017

High-Flow Medalist® MD-23100 Series Elastomers from Teknor Apex Range from Very Soft to Semi-Hard, Need No Pre-Drying, and Have a Light Natural Hue for Ease of Coloring

PAWTUCKET, RI, U.S.A., July 27, 2017: New medical-grade thermoplastic vulcanizate (TPV) elastomers for injection molded O-rings, gaskets, and diaphragms exhibit excellent long-term sealing performance, cost less to process than thermoset rubber, and provide manufacturing advantages over standard TPVs and styrenic TPEs.

Medalist® MD-23100 compounds from Teknor Apex Company provide rubber-like elasticity, superior long-term compression set, and chemical resistance. Unlike some standard TPVs, compounds in the new Medalist series are non-hygroscopic, rendering pre-drying unnecessary, and their lighter natural hue makes them easy to color. Medalist MD-23100 Series compounds also exhibit better high-temperature stability than styrenic TPEs.

Medalist MD-23100 Series TPVs are available with Shore A hardness levels from a soft 15 to a semi-hard 73. With melt flow rates ranging as high as 24 g/10 minutes, the new TPVs are suitable for molding small, high-precision parts in complex, multi-cavity tools. The compounds are suitable for over-molding onto polypropylene.

Teknor Apex recommends the new compounds for sealing components used in devices for drug delivery, fluid transfer, dialysis, endoscopy, and other procedures, and in such equipment as feeding devices, and pumps.  

“The dynamic sealing properties of Medalist MD-23100 Series TPVs enable device manufacturers to obtain excellent long-term performance while avoiding the higher cost and greater complications associated with processing thermoset rubber,” said Ross van Royen, senior market manager for regulated products. “At the same time, these new compounds provide processing advantages over a number of TPV and styrenic TPE candidates for seal applications.”

Teknor Apex produces Medalist MD-23100 Series compounds in ISO-13485 facilities in the USA and Singapore. The new materials comply with FDA requirements for food-grade ingredients, ISO 10993-5 standards for biocompatibility, and REACH SVHC directives. They are free of DEHP and other phthalates, BPA, and latex. Standard grades are ADM-free.

Typical Properties of Medical-Grade Thermoplastic Vulcanizate   

Elastomers for O-Rings and Gaskets

Medalist® MD-23100 Series TPV Elastomers

Typical Properties ASTM Test Method MD- 23115 MD- 23133 MD- 23143 MD- 23153 MD- 23163 MD- 23173
Color --- Opaque Opaque Opaque Opaque Opaque Opaque
Specific Gravity D792 0.89 0.91 0.92 0.93 0.92 0.93
Shore A Hardness (5 sec del) D2240 15 33 43 53 63 73
100% Modulus, psi (MPa) D412 72 (0.50) 159 (1.10) 223 (1.54) 292 (2.01) 435 (3.00) 598 (4.12)
300% Modulus, psi (MPa) D412 208 (1.43) 363 (2.50) 434 (2.99) -- 682 (4.70) 894 (6.16)
Tensile Strength, psi (MPa) D412 256 (1.77) 409 (2.82) 500 (3.45) 512 (3.53) 753 (5.19) 1026 (7.07)
Elongation, % D412 360 350 367 272 327 390
Tear Strength (Die C, 20 in/min), lbf/in (n/m) D624 45 (5.08) 82 (9.26) 102 (11.52) 96 (10.85) 146 (16.50) 206 (23.27)
Compress Set (73°F, 22 hr), % D395 14.2 13.7 15.8 18.6 23.5 26.7
Compress Set (158°F, 22 hr), % D395 28.8 25.8 32.4 29.1 41.1 46.0
Compress Set (212°F, 22 hr), % D395 63.6 43.5 40.4 40.0 47.2 52.1
Melt Flow Rate (200°C / 5.0 kg), g/10 min. D1238 8 15 25 30 25 24