What are the advantages of TPU?
The advantages of TPU compared to other materials are:
| Versus Metal |
|
Versus Plastic |
|
Versus Rubber | |
|
·
|
Lighter Weight |
·
|
Non-Brittle |
·
|
Abrasion
Resistance |
|
·
|
Less Noise |
·
|
Elastic Properties |
·
|
Cut
and Tear Resistance |
|
·
|
Better Wear |
·
|
Abrasion Resistance |
·
|
High
Load Bearing |
|
·
|
Cheaper Fabrication |
·
|
Hydrolytic Stability |
·
|
Clarity
and Color Availability |
|
·
|
Corrosion Resistance |
·
|
Chemical Resistance |
·
|
High
Ozone Resistance |
|
·
|
Shock Absorption |
·
|
Impact Resistance |
·
|
Harder
Durometer Ranges |
|
·
|
Dent Resistance |
·
|
Cold
Temperature Flexibility |
·
|
Hydrolytic Stability |
|
·
|
Recyclable |
|
·
|
Recyclable |
back to top
Are there any processing issues to be aware of when using TPU?
Like many materials, TPU can be affected by too much moisture. TPUs are hygroscopic materials, which absorb moisture rapidly. The following drying procedures should be taken into consideration when drying this material:
| · | Use a desiccant dehumidifying hopper dryer. | |
| · | Hopper dryer capacity should be sufficient to ensure that the resin remains in the hopper at least 2 hours prior to being processed. | |
| · | Hopper inlet air temperature of 180°F to 230°F (82°C to 110°C). For softer materials, use lower temperatures in this range. Temperatures in excess of 230°F (110°C) may cause the pellets to stick together in the hopper. | |
| · | Airflow to the hopper of 1.0 cubic foot per minute (CFM) for every pound of resin per hour of throughput. | |
| · | Dew point of the inlet air to the hopper at 0°F (-18°C) or less. | |
| · | Moisture content in the material should be less than 0.03% prior to processing. |
How does the "Shore-A" hardness scale relate to the "Shore-D" hardness scale?
Elastomeric materials like TPU are differentiated by hardness. A durometer instrument is used to measure surface hardness for the Shore-A and Shore-D scales, the Shore-A scale being softer and the Shore-D scale being harder. Typically, TPUs are made in the 70A to 75D hardness range. The high end of the Shore-A scale overlaps with the low end of the Shore-D scale, so as to provide continuity between the two scales. This often causes confusion in the material selection process. For this reason, we created an abbreviated equivalency chart to facilitate proper selection of materials.
| 100A ~ 75D |
| 95A ~ 50D |
| 90A ~ 40D |
| 85A ~ 32D |
back to top
What type of mold surface is recommended for processing TPU?
Because TPU resins can stick to highly polished surfaces, a rougher mold surface finish may be necessary to provide adequate mold ejection. An SPI D-2 finish (formerly SPE/SPI #5 or vapor hone) is an excellent choice for TPU resin. Where possible, the surface treatment should extend to sprue bushings, runners, etc., to help ensure easy ejection of the entire shot.
back to top
Copyright © 2001 Bay State Polymer
; 
About Us
TPU
TPU FAQs
Nylon
Pre-colored Materials
Other Engineering Resins
Applications Development
Request for Materials
Contact Us