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.

Tips for tooling design with Tritan


 
What makes for effective molding of Eastman Tritan™ copolyester? Reviewing all aspects of design—from concept to secondary operations—early on in the process is crucial to end-stage success.
 
Tooling design review is one important step in the process that will help determine what type of gating system is right for your device. Here are four quick tooling design tips for injection molding with Tritan:
 
  • Proper gating selection
    Select a compatible gating style for the selected resin. Most conventional cold gating styles work well with Tritan copolyesters, including sub, pin, fan, edge, sprue, and diaphragm gates.
 
  • Design tooling with good cooling/thermal control
    Copolyesters require good thermal control throughout the cavity for optimal processing.
 
  • Design tooling with a plan for venting 

Eastman Tritan™ copolyester—superior attributes for medical devices


Eastman Tritan™ copolyester is raising the bar for durability and cleanability in medical devices and housings. BPA-free Tritan’s attributes include exceptional clarity, toughness, improved heat and chemical resistance, and more. It’s also easy to process due to its unique chemical makeup relative to traditional thermoplastics. This blend of processing and performance properties provides greater advantages compared with other commonly used polymers. Available in clear and opaque formulations, Tritan offers many benefits to enhance innovative device designs:
 
Clear formulations of Tritan
  • Greater toughness, heat resistance, processability, and design freedom

Keys to classifying failures for quality engineers


Medical device failures are a common—and costly—occurrence. They can lead to a product recall, affect the product development cycle, and result in extra expenses for manufacturers. The reasons devices fail can be complex, making it difficult for quality engineers to classify the problem.
 
What can quality engineers do to remedy this problem? Consider these factors:
 
  • Understand why failures occur: Most device failures are caused by a misunderstanding of how a material’s properties, processing, and environment work together. In many cases, failures can result from a combination of wrong material selection, poor chemical resistance, high-stress design, or inconsistencies in manufacturing processes.
  • Collaborate with your supplier: Working with material suppliers on material selection, testing, part and tooling design review, and secondary operations can give quality engineers access to knowledge and resources they may not otherwise have.

A safer connection for stopcocks

Drug- and lipid-resistant polymers are playing an increasingly important role in enhancing patient safety. Stringent sterilization techniques can cause cracking, crazing, and hazing in commonly used plastics. They can also have a yellowing effect on certain polymers, which can impact color-coding systems in connector applications.

Eastman Tritan copolyester is resistant to a wide array of medical fluids, such as oncology drugs, drug carrier solvents, and lipids. Along with its toughness, low residual stress, and color stability post-sterilization, Tritan is an excellent choice for fluid management components.

Regulations in the medical market are constantly changing. When Elcam Medical, a world-class manufacturer of disposable medical devices for the OEM market, wanted to further improve the safety and efficacy of its fluid management devices, they turned to Eastman to find a polymer that complies with new regulations while still optimizing performance.

We are putting final touches on plans for Tritan on Tour!



Join us for Tritan on Tour—an exclusive event showcasing how new materials and manufacturing processes can improve medical device performance.

Hear new information about simulating, molding, bonding, and welding Eastman
Tritan™ copolyester.

Gain key insights on the latest with Tritan material and case studies; learn about speed to market through design for manufacturing/design for reliability (DFM/DFR).

Observe a Tritan tool running at the press and on-site presentations/demos from Nexeo Solutions, Beaumont Technologies, Henkel and Dukane!

Plus, we’ll begin the day with donuts and end with cocktails! Hope you can join in the fun!
 
Tritan on Tour—September 11
Advanced Molding Technologies
8700 Rendova Street NE
Circle Pines, MN 55014

Secure connections for safer devices

Small-bore connectors are important components of many enteral feeding devices. Good design is critical, as tubing misconnections or failure can put patients at risk for serious injury or death.

Global design standards for tubing connectors are now helping improve patient safety and device efficacy. ISO 80369 requires small-bore connectors to be made of semirigid and rigid materials, making incorrect interconnections less likely. Enteral devices were the first of all the clinical applications to undergo this change.
To meet this standard, you may have to adjust your design, which means you may need a new mold or new materials. Eastman Tritan copolyester is a rigid material with the properties needed to comply with these regulations.

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

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