Toray Lumirror P52 PET Film and its P525 sibling are both 12 micron pretreated films for metallizing, and the real difference sits on the outside surface
Both are 12 um, both show haze of about 2.6 to 2.7 percent, yet the outside surface is where Toray Lumirror P52 PET Film and P525 part ways: a wetting tension of 43 mN/m on one, 52 mN/m on the other.
Where P52 and P525 Differ
The datasheet covers two grades in one table, and they are close cousins. Both are biaxially oriented polyester films with a special treatment so that they can be metallized very well, while keeping the good features of a standard type. Both come in 12 um only. The differences are small, and they are almost all on the outside surface:
- Outside wetting tension: about 43 mN/m for P52 versus 52 mN/m for P525 (JIS K6768)
- Outside friction, static and dynamic: about 0.45 and 0.40 for P52 versus 0.75 and 0.65 for P525 (ASTM D1894)
- Inside friction: about 0.50 and 0.45 for P52 versus 0.55 and 0.50 for P525
- Haze: about 2.6 percent for P52 versus 2.7 percent for P525 (ASTM D1003)
The datasheet explains the reason for P525. On this grade, the side opposite the metallized side is corona treated, and it keeps good adhesion even after metallizing. That appears to line up with the higher outside wetting tension and the higher outside friction listed for P525.
What the Two Grades Share
Strength and stiffness are identical on paper for both grades:
- Tensile strength: about 235 MPa in MD and 265 MPa in TD (ASTM D882)
- Young’s modulus: about 4.6 GPa in MD and 4.9 GPa in TD (ASTM D882)
The datasheet also lists elongation at break of about 160 percent in MD and 130 percent in TD, and heat shrinkage at 150°C for 30 minutes of about 1.4 to 1.5 percent in MD, with TD close to zero.
What These Numbers Mean for Metallizing
Wetting tension. Wetting tension is a measure of surface energy. In general, a higher value means inks, coatings, and adhesives spread and bond more easily on the surface (a general explanation, not from this datasheet). The inside surface is 43 mN/m on both grades. The outside surface is 43 mN/m on P52 and 52 mN/m on P525, so P525 is the one with the more strongly treated outside.
Why the outside surface matters. In metallized packaging, the film is usually laminated or printed after metallizing, so the back of the film also needs to hold ink or adhesive (a general explanation, not from this datasheet). The datasheet says the corona treatment on P525 keeps good adhesion even after metallizing, which is the point of the higher outside value.
Friction. The coefficient of friction describes how easily film surfaces slide. P525 shows noticeably higher values on the outside (about 0.75 and 0.65), which in general means a grippier surface. A film that slides too easily can be hard to wind and handle, and one that grips too much can be hard to run, so the right level depends on your machines (a general explanation).
Haze. About 2.6 to 2.7 percent is low for a thin, treated film, and the two grades are practically the same. Because the film is metallized, haze usually matters less here than the surface properties.
Strength at 12 um. About 235 to 265 MPa is solid for a 12 um film, with a stiffness of roughly 4.6 to 4.9 GPa. Note that MPa is force per unit area, so the total load a 12 um film carries is still small, and tension control on the metallizing line matters.
Which Grade to Test First
- If your process needs a strongly treated back for printing, lamination, or adhesive bonding after metallizing, start with P525.
- If your process is happy with a standard back surface, or you need a lower-friction outside, P52 is the one to compare.
- Either way, run both through your own metallizing and converting steps. The datasheet values do not replace a line trial.
How It Differs from Neighboring Grades
Two films in the same range are close in use or in thickness:
- Toray Lumirror T62 PET Film is also made for metallizing, but it is a clear film at 25, 50, and 75 um with haze of about 0.6 to 0.9 percent, listed for glossy metallized face labels. P52 and P525 are thinner (12 um), a bit hazier (about 2.6 to 2.7 percent), and listed for candy and snack packaging.
- Toray Lumirror F71 PET Film also offers a 12 um grade, listed for metallic yarn. Its MD tensile strength is higher (about 285 MPa versus 235 MPa), while its TD strength is lower (about 240 MPa versus 265 MPa). Its haze is about 1.5 percent for the 12 um grade.
What the Datasheet Does Not Say
- Food contact: the datasheet says FDA (Food and Drug Administration) compliance is not guaranteed and asks that this film not be placed in direct contact with food. Please design your packaging structure and check the regulations that apply to you accordingly.
- The figures are typical values under specific test conditions and are not limiting specifications, as the datasheet itself notes.
- The datasheet does not state which of the inside or outside surfaces is the metallized side, so confirm this when you order.
- It does not list a thickness tolerance, light transmittance, or gloss values.
- Only 12 um is offered, and only 150°C shrinkage data is given.
Quick Answers Before You Order
What is the difference between Lumirror P52 and P525?
Same base, same 12 um thickness, same strength. P525 has a more strongly treated and higher-friction outside surface, with wetting tension of about 52 mN/m versus 43 mN/m on P52.
Can Lumirror P52 or P525 touch food directly?
The datasheet asks that you do not contact this film to food directly, and it does not guarantee FDA compliance.
What application does the datasheet list?
Packaging of candy, snack, and similar products.
Is this film already treated for metallizing?
Yes. It is described as a pretreated film with excellent adhesion against the metallized layer.
Can I buy Toray Lumirror P52 PET Film from Jinlu Film?
Yes. Jinlu Film supplies Toray Lumirror P52 PET Film and P525. 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.
More PET Film Guides
- Toray Lumirror F552 PET Film: an ultra-thin base film for thermal transfer ribbon
- Toray Lumirror F71 PET Film: a glossy transparent film at 12 and 19 um for metallic yarn and photoresist
- Toray Lumirror H10 PET Film: a hazy plain film for motor insulation
- Toray Lumirror T62 PET Film: a high transparent film for metallizing
- Toray Lumirror T60 PET Film: a high transparent film from 25 to 250 um
Need a Metallizing Base Film?
Jinlu Film supplies Toray Lumirror P52 PET Film, along with comparable pretreated polyester film grades for metallizing, including domestic alternatives. Tell us your metallizing process, thickness, and the surface treatment you need on each side, and contact us for technical data, samples, or a factory quote.
Source: Toray’s publicly available Lumirror P52 and P525 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.
