New Considerations for Medical Equipment Housings: The Case for Specialty Polymers

According to the World Health Organization, of every 100 hospitalized patients, seven in developed and 10 in developing countries will acquire at least one healthcare-associated infection (HAI) — adding up to millions of HAIs every year. These infections can result in higher medical and insurance costs, longer hospital stays and unnecessary deaths. In an effort to combat HAIs, cleaning and disinfection of hospital surfaces has improved significantly. 

While effective, these more aggressive disinfection protocols have a major drawback. They expose plastic medical equipment housings to chemicals that most were never designed to withstand, resulting in an industry-wide problem of cracked equipment housings caused by environmental stress cracking. Consequently, hospitals are burdened with increasing equipment maintenance and repair costs, which contributes to an increase in equipment cost-of-ownership for hospitals and healthcare facilities. Thankfully, medical equipment OEMs hold the key to solving this global healthcare issue: better material selection.

 

Polymer Performance: Key Considerations for Medical Equipment Housings

Polymers commonly used for medical equipment housings — including polycarbonate (PC), acrylonitrile butadiene styrene (ABS) polybutylene terephthalate (PBT) and their blends — are not able to withstand the rigors of more aggressive disinfection procedures, causing them to crack or craze as well as compromising the impact strength required to endure being dropped or mishandled during routine use. Higher performing  polymers — including polysulfone (PSU), polyphenylsulfone (PPSU) and select high-performance polyamides (PA) — deliver on key performance requirements like: 

  1. Better Chemical Resistance: Medical equipment housings made from high-performance polymers are highly resistant to environmental stress cracking when exposed to commonly-used disinfectants like: IPA 70% • Cidex® • Vesphene® IISE • Virex® TB • Clorox® Bleach.
  2. Improved Impact Strength: Portable medical equipment and hand-held devices are more prone to being bumped and dropped, making high  impact strength and key requirement. High performance polymers retain their high strength and impact properties after repeated exposure to chemical disinfectants. This provides more durable components with a longer service life.

 

plastic-degradation-illustration


 

Top Tier Polymers for Medical Equipment Housings

At Solvay, we tailor our polymer solutions to meet the specific demands of a wide range of medical applications, including medical equipment housings and components. Our most popular products fall into one of two categories: semi-crystalline and amorphous polymers.

High-Stiffness Semi-Crystalline Polymers

Semi-crystalline thermoplastic polymers are opaque or translucent and may be unreinforced or compounded with additives such as glass, minerals and impact modifiers.

Kalix® HPPA (high-performance polyamide) products are highly glass-filled compounds that combine a good surface finish with strength, rigidity and dimensional stability. These materials are compatible with modified PC/ABS molds. Selected grades have a UL 94 V0 rating. Typical applications include: Housings • Covers • Chassis • Frames. 

Ixef® PARA (polyarylamide) compounds better suited for metal replacement applications that require newly designed molds. These materials combine very high strength and stiffness along with an exceptional surface finish. Typical applications include: Hinges • Latches • Bag holders • Structural components of hemodialysis machines.
 

Amorphous polymer stress-crack resistance to common hospital disinfectants

semi-crystalline-polymers-resistance-to-hospital-disinfectants

Retention of tensile and impact properties, 7-day exposure under strain at 23°C

 

Tough Amorphous Polymers

Amorphous thermoplastic polymers are inherently transparent materials and predominantly unreinforced.

Udel® PSU (polysulfone) is known for its toughness, stability, and strength at high temperatures. It serves as an upgrade to polycarbonate (PC) and is compatible with existing PC tooling. Typical applications include: Equipment housings • Connectors • Couplings • Humidifier housings • PEEP chambers.

Radel® PPSU (polyphenylsulfone) delivers the highest performance of all sulfone polymers. This super-tough polymer offers unparalleled retention of mechanical properties when repeatedly exposed to strong chemical disinfectants. Typical applications include: Hand-held device housings • Connectors • Impellers • Reagent trays • Racks • Vial holders for in-vitro diagnostics.
 

Amorphous polymer stress-crack resistance to common hospital disinfectants

amorphous-polymers-resistance-to-hospital-disinfectants

Retention of tensile and impact properties, 7-day exposure under strain at 23°C

 

Selecting the Right Polymer Begins with Selecting the Right Partner

Reducing medical equipment cost-of-ownership starts with better material selection. Only medical equipment housings made with high-performance polymers will adequately withstand new disinfection protocols necessary for reducing HAIs in hospitals around the world. 

Consulting an experienced polymer supplier like Solvay early in the design process can help OEMs not only select the right material, but ensure that the material is leveraged correctly. Service differentiators like Mold Flow(R) process modeling, Finite Element Analysis, fabrication and assembly techniques, product reviews, failure analysis and  on-site materials training and  processing support all play a crucial role in how the right materials supplier can help OEMs fight against HAIs while reducing medical equipment cost of ownership.

At Solvay, we are more than a materials supplier — our best-in-class polymer service package sets us apart as a trusted partner. Contact us to learn more about how we can help your team select the right polymer solution for your project, or learn more about specialty polymers for medical equipment housings in our webinar below.