Understanding TPU Powder
Most of us work with TPU Powder daily, so I thought it was important that we understand the material and its compounds better.
Read this article to get a good idea of what TPU is used for and the limits we can push it to, insuring we get the most out of every grain.
TPU USES
TPU has many applications, including automotive instrument panels, caster wheels, power tools, sporting goods, medical devices, drive belts, footwear, inflatable rafts, and a variety of extruded film, sheet and profile uses. TPU is also a popular material found in flexible outer cases of devices like mobile phones and keyboard protectors. You find TPU used in a variety of tools and objects in your daily life. It's not new and understanding TPU properties a little better will certainly help with your OVERALL Direct To Film Printing quality.
What is TPU powder?
THERMOPLASTIC POLYURETHANE.
TPU resin consists of linear polymeric chains in block-structures. Such chains contain low polarity segments which are rather long (called soft segments), alternating with shorter, high polarity segments (called hard segments).
Both types of segments are linked together by covalent links so that they actually form block-copolymers. The miscibility of the hard and soft segments in TPU depends on the differences in their glass transition temperature. The polarity of the hard pieces creates a strong attraction between them, the formation created is what seals our prints and bonds our inks to our substrates and forms crystalline or pseudo crystalline areas located in a soft and flexible matrix. Which is why TPU Powder is so useful in Direct To Film Prining applications.
The crystalline or pseudo crystalline areas act as physical cross-links, which account for the high elasticity level of TPU, whereas the flexible chains will impart the elongation characteristics to the polymer.These "pseudo crosslinks", however, disappear under the effect of heat, and thus the classical extrusion, injection molding, and calendering processing methods are applicable to these materials. Consequently, TPU scrap can be reprocessed.
WHY TPU IS PERFECT FOR DTF
PROPERTIES OF TPU INCLUDE:
-High abrasion resistance, low-temperature performance, high shear strength, high elasticity & transparency. Perfect for Direct To Film Transfers.
-Oil and grease resistance. (which why we see so much grease)
TWO MAIN GROUPS OF TPU POWDERS:
-Polyester-based TPUs (THESE ARE THE TPU'S USED IN DTF)
-Polyether-based TPUs (USED IN INJECTION MOLDING FOR HARDER LESS TRANSPARENT FINISHES).
Understanding how TPU works and why can help every business make better use of their TPU Powders, increase quality and longevity of their Direct To Transfer prints.
Leave a comment, tell us how you have been using TPU powder for your applications, join the forum and share what you have learned and how you use TPU on various substrates.
Joel Bowman - Ink Drop Printer Services
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