The effect of electron beam sterilization on Eastman Tritan™

Sterilizing medical devices helps reduce the bioburden to a safe level with minimal effects on the physical and optical properties of its polymers. Some of the most widely used sterilization methods in the medical industry today include gamma radiation, ethylene oxide (EtO), autoclave, and low-temperature hydrogen peroxide gas plasma. Another method gaining in popularity is electron beam (e-beam) radiation. It’s a safe, reliable source of energy thanks to recent advancements in operating efficiency.
 
Compared to gamma radiation, e-beam radiation typically costs less due to higher dose rates that reduce the time of exposure at the same target dose. The shorter exposure time also minimizes the oxidation reactions that can occur at the polymer surface, resulting in less effect on resin properties than with gamma radiation.

Overmolding with Tritan

Using overmolded soft-touch materials can provide many functional and decorative benefits to items made from rigid thermoplastics. Eastman Tritan™ copolyester demonstrates exceptional adhesion with commercial grades of TPE. When selecting the TPE you want to use, make sure it is formulated for use with a copolyester substrate.
Consider these factors for part design:                 
  • Optimize part and TPE thickness for adhesion and dimensional stability. If the TPE thickness is in excess of the Tritan part thickness, you could see warpage when you remove it from the mold. Use a substrate thickness twice that of the TPE.
  • Incorporate mechanical interlocks to improve TPE adhesion and promote part durability. Mechanical interlocks are important for thin TPE layers and very demanding fitness-for-use requirements.

Educating product managers on how plastics affect your brand

 

The material you choose for your medical devices can have a big impact on your brand’s image. In today’s healthcare environment, not all plastics can withstand exposure to the aggressive disinfectants being used in hospitals. If your device is showing outward signs of suffering from exposure to effects of disinfection, including yellowing, cracking, crazing, or paint peeling, it’s time to reconsider material selection.

 

Polymer compatibility with oncology drugs

As part of the continued effort to improve cancer treatment, pharmaceutical companies are developing new and improved oncology drugs. However, advanced oncology drugs and carrier solvents challenge the chemical resistance of polymers used in delivery devices. Such conditions can prevent devices from working properly or cause them to fail prematurely. When there is a pattern of compromised device performance or life cycle, regulatory agencies may tell manufacturers to stop using certain materials to protect patient safety.
 

Better bonds between polymers and adhesives

We often receive requests from medical device developers and original equipment manufacturers for guidance on the best adhesives to use with Eastman TritanTM copolyester. To help customers achieve the best adhesive solutions, we partnered with Henkel Corporation to test various resins and adhesives for use in medical devices.
 
Henkel’s LOCTITE® adhesive continues to be tested at the industry’s most comprehensive ISO 10993 biocompatibility standards. Eastman looked to determine which resins and adhesives, when used with Tritan, could optimize a manufacturer’s assembly process. Results showed that the use of Tritan and LOCTITE together created superior results, including improved
curing to increased flexibility.
 

Creating strong bonds with LSR technology and Tritan

Medical devices and housings are getting a surge of chemical resistance and impact strength thanks to the integration of new liquid silicone rubber (LSR) technology with medical grades of Eastman Tritan™ copolyester. Momentive’s Silopren LSR 47×9 series provides strong in-mold adhesion with Tritan—without the need for primers.
 
Clear and opaque grades of Tritan have a lower Tg and require a lower processing temperature than other engineering polymers. Because Silopren LSR 47×9 can cure rapidly at relatively low temperatures, it’s possible to achieve optimal functional performance and efficient processing with Tritan.

This combination is ideal for applications that require properties like handling comfort, waterproofing, durability, and aging stability. Incorporating LSR technology enhances the advantages of Tritan, which include:
  • Outstanding chemical resistance
  • Excellent impact strength and durability
  • Made without bisphenol A (BPA) and halogens
  • Superior noise-damping characteristics

Four steps for testing housing material performance

When exposed to commonly used aggressive disinfectants and drugs, many materials used in medical devices can crack, craze, discolor, and become sticky. Currently, there are no industry standards for evaluating surface compatibility. That’s why Eastman developed a 4-step test method based on ASTM standards to better understand why plastics fail and how different plastics perform in the real world.
 
This simple, easily-repeatable test can help predict the reliability of a material after exposure to harsh cleaners and drugs commonly used in hospital settings. The method uses a 1.5% constant strain jig together with wet patches for applying chemical reagents. Here’s how it works:
  1. Select the appropriate jig.
  2. Load flex bars onto jig.
  3. Apply chemicals to the flex bars.
  4. Perform reverse side impact test.

A preferred supplier that goes the extra mile

At Eastman, we go above and beyond the typical duties of a preferred supplier. Unlike many of our competitors, Eastman provides you with regulatory and technical services to help you through the manufacturing process—at no extra cost to you. This guidance, along with access to our high quality, innovative materials, will elevate your brand and ensure that you’re optimizing our polymers for your devices.
 
Our regulatory group stays current with global regulatory changes and makes this information readily available to the market. We provide you with all the necessary regulatory information for the safe use of our polymers, including details on compliance with Food and Drug Administration standards, chemical and mechanical properties, and more.
 
We also offer premium technical service for all aspects of the molding process, from conception through bringing your product to market. Eastman Design Services capabilities include:
 

Thank You for Asking

We often receive great questions about molding with Eastman medical grade polymers and are always glad to provide answers and more information. Here is a response to a recent query from our inbox:
 
“How environmentally friendly is Eastman MXF221 copolyester?”

Eastman strives to create solutions that offer more value with less environmental impact.
MXF221 copolyester is one of our many environmentally responsible offerings that meets
industry standards for safety and sustainability. Some of its innovative properties include:
  • It’s made without BPA, halogens, or ortho-phthalate plasticizers.
  • Its toughness and durability can potentially increase product life and reduce waste.
  • The flame-retardant additives used in do not contain antimony, bromine, or chlorine.
  • It’s suitable for transducer housing applications that require contact with the skin.
Read more about how Tritan is improving sustainability and design for devices and diagnostics.

Colorful possibilities with Eastman MXF221 copolyester

Eastman MXF221 copolyester, available as a clear-natural or opaque-colored polymer, provides excellent chemical resistance and durability and is uniquely suited for electronic medical device housings. Not only is it extremely tough and able to stand up to the daily stresses of hospital environments, but it’s also compatible with branding initiatives.
 
Brand owners who use opaque polymers often require precise color matching and vibrant aesthetics to maintain their brand identities. Eastman MXF221 copolyester comes in a wide array of colors with the ability to align seamlessly with any brand standards.
 

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