A TPE so soft, we can’t even tell how soft it is

A new transparent medical-grade elastomer compound is so soft that it could not be accurately measured using the standard Shore A scale, but these plastic pellets are still said to be easy to handle for running on standard injection molding systems.

According to its supplier, plastics compounder Teknor Apex, the new compound, called Medalist MD-447, is so soft that it could not be measured accurately on the Shore A hardness scale used for other elastomers. Subjected to the Shore OO test for ultra-soft materials, the new compound has a rating of 25. The accompanying table lists key physical properties of the material.  

The elastomer gel available is likely to see use in skin-contact and other sensitive applications requiring molded-in seal areas or cushions. According to Lisa Charno, medical market manager at the compounder, the pellets' softness won't be cause for handling problems. She explained, "Teknor Apex has considerable experience with gel elastomers used commercially in non-medical applications. We applied that experience to formulate a gel that achieves new levels of softness yet flows freely in pellet form and is readily processed in standard injection molding machines."
 
Based on a standard hydrogenated styrenic block copolymer, Medalist MD-447 is free of latex, phthalates, or animal-derived components, and complies with FDA, California Proposition 65, CONEG, and REACH requirements for medical applications.
 
The company's Medalist compound range for medical applications now includes 28 standard high-purity elastomer compounds. Compounds are available with hardness from Shore OO 25 to Shore A 87.