DTF Transfer Safety
Adhesive powder (TPU)
The thermoplastic polyurethane that bonds the print to the garment: fully reacted, what that means, and what it does at the press.
What it is
After printing, the wet ink is dusted with a fine white powder of thermoplastic polyurethane, or TPU. Excess powder is shaken off, and the sheet is cured: the powder melts into the ink layer and sets into a continuous, flexible adhesive film. At the press it melts again, flows into the fibres of the garment, and bonds the print to the fabric as it cools.
The manufacturer describes the powder as a fully reacted thermoplastic aromatic polyurethane. That phrase matters. Polyurethanes are made by reacting isocyanates with polyols. In a fully reacted thermoplastic the isocyanate groups have been consumed during manufacture; what is left is a stable solid polymer that softens with heat and re-solidifies when cooled, over and over, without any further chemistry. The manufacturer's safety information carries no hazard classification for the powder; its guidance is about dust, and dust is a matter for our production floor, not for you.
- Form
- White powder; fully reacted thermoplastic aromatic polyurethane; insoluble in water
- Classification of the input
- The manufacturer's product safety information carries no GHS hazard classification, pictogram or signal word. Its guidance is to avoid breathing the dust and to use ventilation and protective equipment when handling the loose powder.
- Melting range (DSC)
- 105 to 118 °C (221 to 244 °F)
- Hardness
- Shore A 75
- Melt flow rate
- 28 g / 10 min
- Wash resistance
- Up to 60 °C (140 °F)
- Particle size grades
- 0 to 50 µm and 80 to 200 µm
- Water solubility
- Insoluble
- Ignition
- May burn but does not ignite readily
Hot-melt adhesive powder (thermoplastic polyurethane) — composition as reported by the manufacturer
| Component | CAS | Share | Role | In the finished transfer |
|---|---|---|---|---|
| Thermoplastic polyurethane (TPU), fully reacted | — | 100 % (as supplied) | Hot-melt adhesive — melts at the press and bonds the printed film to the fabric | Remains in the finished transfer |
Shares are the manufacturer's reported weight percentages. Humectants are driven off during drying and curing; trace residues are possible.
What "fully reacted" does and does not tell you
It tells you the adhesive is a finished polymer, not a reactive system. It is the reason there is no "cure time" chemistry at your press: the bond forms by melting and cooling, not by a reaction. It does not tell you the residual content of unreacted isocyanate, because the manufacturer's safety information does not report one and we have not tested for one. We state that gap rather than fill it.
At the press
The powder's melting range is well below our recommended press temperature, which is why the bond forms in seconds. Polyurethanes begin to break down at much higher temperatures than that; published studies put the onset of thermal decomposition for thermoplastic polyurethanes at roughly 250 °C and above, far past where a heat press operates. Pressing safely has the detail, including what burning a polyurethane releases.
Dust is our hazard, not yours
The manufacturer's handling guidance, which is about avoiding airborne powder, applies to the loose material in our plant. A cured transfer has no loose powder on it: the adhesive is a smooth, fused layer. If you ever receive a sheet with loose white powder on it, do not use it; contact us and we will replace it.
Washing
The manufacturer rates the adhesive's wash resistance to 60 °C (140 °F). That is a durability rating for the bond, not a safety limit; Wearing and washing has our care recommendations.