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.

 

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.

Secondary Operations: Adhesive Bonding

증발하는 용제와 달리 접착제 층은 완성된 조립품의 기능적 구성요소로 남게 됩니다. Therefore, the characteristics of the adhesive layer play a key role in the performance and appearance of the finished part.
 
Consider these characteristics when selecting an adhesive:
  • Chemical compatibility with parts being joined
  • 완성된 접합부의 미적 요소
  • Expansion/contraction with temperature changes (NOTE: if expansion/contraction are a major concern, consider mechanical fasteners.)
  • 취성, 강성, 유연성
  • 내구성/서비스 수명
  • 접착 강도(플라스틱과의 접착 부위)
  • 응집 강도(내부 인열 저항)
  • 최종 사용 요건
 
Eastman Tritan copolyester offers outstanding chemical resistance and has been studied with many adhesives and different bonding procedures. 
Adhesive bonding procedures for Eastman Tritan copolyester     
When adhesive bonding parts made with Tritan, joining surfaces should:
  • Fit well without forcing
  • Have no visible gaps

이차 공정: 오버몰딩


오버몰딩된 소프트터치 물질은 견고한 열가소성 플라스틱 엘라스토머(TPE) 소재의 제품에 기능성 및 장식적 요소를 추가할 때 주로 적용됩니다. Eastman Tritan 코폴리에스터는 상용 TPE 등급에 뛰어난 접착성을 보입니다. 성공적인 결과물을 위해서는, TPE 등급 선택 및 부품 디자인에 앞서 TPE 공급업체 또는 Eastman과 상의하여 코폴리에스터 기판에 사용할 수 있는 성질의 등급을 우선적으로 선택하셔야 합니다.

부품 디자인 고려 사항:                 

  • 접착과 치수 안정성을 위해 부품 두께 및 TPE 두께를 최적화합니다. TPE 두께가 Eastman Tritan코폴리에스터 부품 두께를 초과하면, 금형에서 제거할 때 비틀림이 발생할 수 있습니다. 일반적으로 권장되는 기준은 기판 두께를 TPE의 두 배로 하는 것입니다.
  • 기계적 인터로크를 적용하여 TPE 접합력을 향상하고 부품 내구성을 증가시킬 수도 있습니다. 기계적 인터로크는 TPE 층이 얇거나 용도 적합성 요건이 엄격할 때 특히 중요합니다.
  • 여러 표면에 소프트터치를 적용하는 디자인의 경우 플로스루(flow-through) 디자인을 사용하여 접합력과 내구성을 향상시켜야 합니다.
  • 박피 또는 박리 가능성을 최소화하려면 TPE의 모서리가 견고한 기판의 오버몰딩되지 않은 부분과 같은 높이를 유지해야 합니다.

Troubleshooting Focus: Flashing

Proper mold design provides a giant step toward reducing problems like flashing when injection molding with Eastman Tritan copolyester and other Eastman copolyesters. Collaborating with an Eastman technical service representative early in your project can help ensure you’re off on the right foot.

To help ensure continued molding success, this blog focuses on three different types of flashing problems, their possible causes, and corrective actions you can take for each.