Teknor Apex lends materials expertise to development of first nasal-only ventilation mask

The first nasal-only alternative to standard full-face oxygenation and ventilation masks that have been medical mainstays for many decades relies on the sealing and cushioning capabilities of a super-soft thermoplastic elastomer (TPE) developed by Teknor Apex (Pawtucket, RI).

The patent-pending, single-use SuperNO₂VA mask from Revolutionary Medical Devices Inc. (RMD; Tucson, AZ) consists of a transparent, rigid polypropylene (PP) component with access ports for an anesthesia circuit or hyperinflation bag, plus a TPE cushion that is over-molded onto the PP structure. The TPE cushion, molded of Medalist MD-10105 medical elastomer from Teknor Apex, plays a critical role by providing a strong yet comfortable seal to the patient’s face.

Over-molding the TPE onto a PP substrate proved to be challenging, explained Chris Morehouse, Market Manager, Regulated Products, for the TPE Division of Teknor Apex. “The lower the durometer of the TPE, the more difficult it is to make it adhere to PP,” said Morehouse. Moreover, the “TPE part is complex, with thick- and thin-wall sections and recessed areas, or undercuts, that must retain their shape during ejection of the part from the mold,” said Morehouse.

Morehouse brought together the RMD and Teknor Apex teams to discuss these challenges, noted RMD’s Tom Reilly. “We made trips to the Teknor Apex application development lab in Leominster, MA, and their facility in Kentucky. Teknor Apex reformulated the TPE to attain exactly the durometer we wanted while still achieving a strong bond to the PP part. In an over-molding process at Leominster, they demonstrated that the TPE would bond successfully.”
 
The massive undercut at the nose section of the TPE cushion calls for a compound with a high degree of strength and elongation, noted Ryan Redford, RMD’s Director of Product Development. “Typically an undercut with a material that soft would tear apart,” he said, “but the cushion came out of the mold with absolutely no problem. To this day our contract molder is impressed with the Medalist compound.”

RMD uses the China-based contract molding subsidiary of a U.S. company to injection mold the components for the SuperNO₂VA mask. The cushion part is produced in blue, green, pink or yellow for purposes of color coding. Teknor Apex supplies the Medalist MD-10105 in pre-colored compounds from a U.S. plant and will supply identical grades from a plant in Singapore once it receives ISO-13485 certification, which is expected by December of this year.

Use of sedation in medical procedures is on the rise as a result of more sophisticated surgical techniques, an aging population and a greater incidence of obesity, according to Michael Pedro, MD, Chief Medical Officer and co-founder of RMD. “The SuperNO₂VA mask is an efficient and versatile alternative to full-face masks and nasal cannulae, and it is particularly advantageous for intra-oral procedures such as upper endoscopies and bronchoscopies,” said Pedro.