Coloring TPU and thermoplastics: masterbatch vs liquid color
Thermoplastics run on masterbatch, a solid pellet concentrate let down at the machine. Here is how that differs from the liquid color used for cast PU, and how we match across both.
Thermoplastics run on masterbatch, a solid pellet concentrate let down at the machine. Here is how that differs from the liquid color used for cast PU, and how we match across both.
Color format follows the process. Cast polyurethane and other liquid resin systems are colored before cure, while the resin is still a metered liquid. TPU and other thermoplastics are colored during molding or extrusion, while the resin is a melt. Each process takes the format built for it.
We supply both and color-match across both. For a shop that casts PU and also molds or extrudes TPU, we hold one color target across the two deliverables, so a part made either way reads the same shade.
Masterbatch is pigment pre-compounded into a solid pellet carrier resin matched to your material. The pellets feed into the press or extruder alongside the natural resin, melt together in the barrel, and disperse as the screw conveys the melt to the cavity or the die.
The process is solid-state at the machine: pellets in, colored part out, no liquid lines to manage. For molders and extruders, that means clean changeovers, predictable feeding, and color that disperses in the melt. Our masterbatch is built for the polyurethane family, covering both thermoset PU and TPU grades, with the carrier resin matched to your material so the concentrate melts and disperses cleanly.
Liquid color is pigment dispersed in a liquid carrier, metered into a liquid resin before it cures. It is the format for cast PU, PU and epoxy systems, flexible PVC, and PU foam, where addition happens in the liquid phase. It pours and meters at low viscosity and develops color in the mix, which is what those systems need.
The two are different finished products for different stages of manufacture. Liquid color goes into a liquid resin before cure. Masterbatch goes into a melt during molding or extrusion. For cast PU the deliverable is the liquid dispersion. For TPU and thermoplastics the deliverable is masterbatch.
Liquid dispersion.
Liquid dispersion.
Liquid dispersion.
Masterbatch (pellet).
Masterbatch (pellet).
Masterbatch (pellet).
The match comes first, the format second. Send a PANTONE, RAL, Federal Standard 595, hex, or physical reference, tell us the resin and the process, and our technicians build the color for that system. For a part you make both by casting and by molding, we hold the shade across the liquid dispersion and the masterbatch so the two read the same. We also reverse-match a color you already buy, in either format. See the TPU and elastomers page for the Laripur TPU line itself.
Our US-made liquid color qualifies as a Berry Amendment compliant component for military and government footwear and textile programs. Masterbatch is different: the pigment is compounded into a base resin that may be imported, so a masterbatch follows the country of origin of that carrier resin rather than the compounding step.
If your part is a molded or extruded thermoplastic and the program requires domestic content, tell us the requirement and the resin, and we will confirm what we can supply. For Berry-compliant, US-made color, see liquid color for cast PU.
The same target color can be matched in both formats: a liquid dispersion for the cast PU and a masterbatch for the TPU. The shade is held across the two so the parts read the same, even though the carriers and the processes differ.
Liquid color is built for liquid resin systems. In a thermoplastic melt the liquid carrier can flash off or cause feeding and screw-slippage problems, especially at higher addition levels. Thermoplastics are colored with masterbatch, which melts and disperses with the base resin.
Cast PU takes liquid color, added to a liquid resin before cure. TPU and thermoplastics take masterbatch, melted in during molding or extrusion. The format follows the process, and we match across both.
Our US-made liquid color qualifies as a Berry Amendment compliant component. Masterbatch is compounded into a base resin that may be imported, so its country of origin follows that carrier resin. If a thermoplastic part has to meet domestic-content rules, tell us the requirement and the resin and we will confirm what we can supply.