New TPEs are developed on a daily basis, for many reasons: new polymer technologies offered by our suppliers, evolving consumer preferences, or the newest government regulation.Depending on your application or end-use environment, you may already know if you need an SBC compound versus a TPV, but how do you choose the right grade? TPEs can be custom-formulated to fit an extremely wide range of performance requirements, so choosing the right TPE can be tricky – even for the experts!We always start with an outline of the application’s requirements, and then translate them into material requirements. 2. Manufacturing Process: Formulating for Processability 3. Cost Targets: Balancing Price & Performance 4. Environmental Conditions: Use and Exposure ·Temperature Requirements 5. Regulatory Concerns: Industry and Market 6. Aesthetics & Surface Appearance: Determine Look & Feel 7. Material Performance: Property Prioritization
Use This Checklist to Guide You Through This Process
1. Intent for TPE Selection: New Grade or Material Replacement
It’s important to understand what material is currently being used, for example PVC or silicone rubber, or even another TPE and where improvements are needed or if there’s a price target.
If this is a brand new application for a TPE, note any functional or performance requirements.
Consider how the part will be manufactured and assembled. TPE formulations are adjusted based on how the material is processed, and can be tailored for injection molding, extrusion, or blow molding. Specialty high-flow TPEs have been developed for complex parts with thin and thick sections or severe undercuts.
Quite often, there are cost targets involved in material selection, either defined in cost per pound or cost per part. Even having an estimate in mind will aid in making the decision.
Will the product be used indoors, or outdoors, or both? What temperatures will it be exposed to and is chemical resistance required? If the TPE is used in a seal, for example, will it be under load or repeatedly flexed? Consider these end-use conditions to determine if additives or specialty ingredients are needed:
·Exposure to UV or extreme weather conditions
·Chemical exposure
·Usage
Whether you’re designing a medical device or a pipe seal, there are rules and regulations that apply, depending on the industry and world region. Certifications or additional testing may be required, and may effect the choice of ingredients used in the TPE.
TPEs can be tailored to meet specific aesthetic requirements and are typically characterized by feel, finish, and color.
The physical and thermal properties of a TPE are directly related to its composition and method of manufacture. If there are specific requirements for properties like hardness or performance like tear strength, those should be noted early in the material selection process.
Consider these factors to start:
·Hardness
·Stretch and Bounce-Back
·Compression Set
·Abrasion Resistance or Resistance to Wear -
·Tear Strength or Puncture Resistance
·Resistance to Bending
·Adhesion to Other Materials
·Special Requirements