What the Anti-Stick Backcoat Changes in Toray Lumirror F531 PET Film

Toray Lumirror F531 PET Film is an anti-stick film specially designed for bar code ribbon at 3.5, 4.5, and 5.7 micron, back coated to run cleanly past the print head

Anyone who has watched a thermal transfer ribbon jam knows the cause: the back of the film sticks to the hot print head. Toray Lumirror F531 PET Film answers that problem directly, with a back coated anti-stick layer.

What the Backcoat Is For

According to its datasheet, F531 is an anti-stick film specially designed for bar code ribbon, back coated with an anti-stick layer. In a thermal transfer ribbon, the print head heats the back of the film, and without a protective layer the polyester can soften, stick, and drag (a general explanation, not from this datasheet). The datasheet lists excellent runnability, good handling properties, heat stability, and good mechanical properties as the film’s properties, and the application as thermal transfer ribbon in general.

The Numbers the Datasheet Gives

  • Thickness: 3.5, 4.5, and 5.7 um
  • Tensile strength: about 305 to 345 MPa in MD and about 245 to 275 MPa in TD (ASTM D882)
  • Elongation at break: about 98 to 120 percent (ASTM D882)
  • Heat shrinkage at 150°C for 30 minutes: about 2.0 percent in MD and about 0.8 to 1.0 percent in TD (ASTM D1204)
  • F-5 value: about 105 to 115 MPa (ASTM D882)
  • Coefficient of friction, film to film: about 0.18 to 0.19, with the inner side at about 0.14 to 0.16

The friction figures are the story. A coefficient near 0.18, with the backcoated side lower, is a slippery surface, which is exactly what lets the film glide past the print head instead of sticking to it. The F-5 value is generally the stress needed to stretch the film by 5 percent (a general explanation), and about 105 to 115 MPa means the film resists stretching under printer tension. Note that MPa is force per unit area, so at 3.5 um the total load the film carries is tiny, and tension control matters.

How It Differs from Neighboring Grades

  • Toray Lumirror F53 PET Film is the plain, uncoated ribbon base at the same three thicknesses, with friction of about 0.40 to 0.50 and surface roughness of about 0.10. F531 adds the backcoat, and the friction figures drop to roughly 0.14 to 0.19. If your ribbon line applies its own backcoat, F53 is the base. If you want the anti-stick layer already on the film, F531 is the one.
  • Toray Lumirror F552 PET Film is the adhesion promoted base for dye diffusion ribbon at 4.5 and 5.7 um, a different ink system from the bar code ribbon F531 targets.

What the Datasheet Does Not Say

  • The values are typical data under specific test conditions and are not limiting specifications, as the datasheet itself notes.
  • No description of the backcoat chemistry, thickness, or durability is given, and no surface roughness, haze, or thickness tolerance is listed.
  • Several figures could not be matched to a specific thickness. Some numbers are approximate ranges. Please check the official datasheet for exact values at your thickness.

Quick Answers

What is Lumirror F531?
An anti-stick polyester film specially designed for bar code ribbon, back coated with an anti-stick layer.

What thicknesses does the datasheet cover?
3.5, 4.5, and 5.7 um.

What is the difference from F53?
F53 is the plain ribbon base, and F531 is the version with the anti-stick backcoat, with much lower friction.

Can I buy Toray Lumirror F531 PET Film from Jinlu Film?
Yes. Jinlu Film supplies Toray Lumirror F531 PET Film. If you prefer a comparable-specification alternative, including domestic options, we can offer those as well, together with datasheets and samples so you can test them on your own line.

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Sourcing Back Coated Ribbon Film

Jinlu Film supplies Toray Lumirror F531 PET Film, along with comparable anti-stick back coated polyester film grades, including domestic alternatives, for bar code and thermal transfer ribbon. Tell us your ribbon type, thickness, and backcoat needs, and contact us for technical data, samples, or a factory quote.

Source: Toray’s publicly available Lumirror F531 technical data sheet (typical values). Please refer to the latest official version. Lumirror, Toray, and related names are trademarks of their respective owners. This article is an independent explanation for reference only.

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