By Richard Rabe

Related links: TPE | Understanding TPEs - Part 1

There are a variety of TPE technologies available offering a wide range of mechanical properties and end-use performance. In may cases, the performance range of different TPE polymers overlap and make specific grade selection uncertain.

Knowing how a material will be used in its end-use application is imperative during the material selection process. RTP Company product development engineers are well versed in seeking out the information necessary to ensure an appropriate material is recommended. This TPE application checklist has been developed to help you prepare thoughtful answers to common questions.

TPE Application Checklist

A complete description of the application and its function or purpose?

• What fabrication and assembly processes will be used?
• If co-extrusion or overmolding process, what substrate material?
• Is an existing material being replaced?

At what stage is the application in the design cycle?

		Concept
		Drawing
		Tooling
		Prototype
		Material specification

Is there a cost target for a material to be considered?

• Material cost per pound?
• Material cost per part?

Are there temperature requirements?

• Maximum service temperature?
• Minimum service temperature?
• Constant use temperature?
• Length of exposure to extreme temperatures?

Will there be exposure to environmental conditions?

• Indoor, outdoor, or combination of use conditions?
• UV exposure that may affect color or properties?
• Exposure to specific chemicals?
  

  		Acids
  		Bases
  		Oils
  		Others

• Time length of exposure to conditions?
• Temperature during exposure?

Are there any regulatory requirements?

• Flame retardant to UL or other agency standard?
• Meet a specific automotive specification?
• Comply with FDA or NSF for food or water contact?
• Comply with USP class VI for a medical device?
• Comply with European ATEX regulations?

Are there any physical property requirements?

• Tensile strength?
• Tensile elongation (yield or break)?
• Tensile Stress (50% strain, 100% strain, or 300% strain)?
• Flexural modulus?
• Hardness (Shore A or Shore D)?
• Tear strength?
• Compression set (at temperature)?
• Tensile set (at temperature)?
• Rheology requirements (viscosity or melt flow)?
• Specific gravity target?
• Wear resistant or friction against a specific material?

Any other specific property needs?

• Conductivity?
  

  		Anti-static
  		Static dissipative
  		ESD protection
  		EMI shielding

• Structural or reinforcement requirements
  

  		Glass fiber or minerals
  		Density modification
  		ESD protection
  		EMI shielding

• Color or appearance?
  

  		Match custom color
  		Masterbatch
  		Transparent/translucent

For most applications not all of these properties will be applicable. There also may be specialized application needs that are not included on this list. By asking the right questions and through probing for the application needs, the true application requirements can be obtained and matching the right material can begin.