PET Film Technical Data Sheet

A PET Film Technical Data Sheet is used to compare polyester film grades before coating, printing, lamination, slitting, die cutting, insulation use, clean-surface converting, functional coating, or adhesive-layer processing. This reference explains the density of pet film, the density of polyester film, thickness conversion, GSM, roll weight, pet film mechanical properties, pet film optical properties, dyne level, corona treatment, COF, and dimensional stability.  For GSM, roll weight, yield, and finished structure review, use polyester film density calculation together with PET mechanical and optical data. Values are typical references only. Final approval should be based on the actual grade, surface treatment, testing method, storage condition, and real production process. Where a project needs a material-level optical constant rather than haze or transmittance alone, review PET film refractive index measurement data, including wavelength, temperature, and film-direction reporting.

For roll supply, coating and converting choices, see our PET films for industrial processing applications.

PET Film and Polyester Film Data Meaning

PET film and polyester film usually describe the same industrial material family: polyethylene terephthalate film. For a practical explanation of how these names affect sourcing language, surface treatment, and sample approval, read our PET vs polyester film guide before comparing grades only by thickness or density. BOPET film means biaxially oriented PET film, produced by stretching the material in both machine direction and transverse direction. This orientation improves strength, stiffness, dimensional stability, and web handling compared with many non-oriented plastic films.

A polyester film technical data sheet should show how each value affects processing. When the material choice is between PE protective film and PET film for converting, this PE vs PET film test comparison shows which data points should be checked before selecting a trial roll.
Density affects GSM and roll weight. MD/TD tensile data affects web tension and shrinkage balance. Optical data affects visibility and inspection. Dyne level affects wetting. COF affects winding, feeding, blocking, and registration stability. For material teams still comparing BOPP and polyester film, this BOPP vs PET film selection guide explains how these data points affect printing, coating, slitting, and die cutting decisions.

Density, GSM and Roll Weight Calculation

The density of pet film is a base value for GSM, roll weight, square-meter yield, load calculation, and cost comparison. General clear PET or BOPET film is commonly estimated at 1.38-1.40 g/cm3, and 1.39 g/cm3 is often used for quick calculation. The density of polyester film can change with pigments, fillers, matte additives, anti-static additives, primer layers, release layers, hard coatings, conductive coatings, or other surface treatments.

For unit conversion, GSM, yield, and roll-weight checks, use the PET film density and roll-weight technical data.

PET Film Mechanical Properties

Pet film mechanical properties should be checked in both MD and TD. MD is the machine direction, following film travel. TD is the transverse direction across the film width. Because PET film is oriented, tensile strength, elongation, modulus, and shrinkage can differ between these two directions.

Thermal Shrinkage and Dimensional Stability

PET film is often selected when dimensional control is important, but shrinkage must be tied to test condition. The same material can show different results at 105 C and 150 C. Free-shrink testing can also differ from a process where the film is under web tension, lamination pressure, coating stress, or adhesive stress.

For coating, printing, lamination, slitting, die cutting, insulation layers, clean-surface converting, and adhesive-layer processing, confirm MD and TD shrinkage separately. Test temperature, dwell time, film state, tension, pressure, and storage condition should match production as closely as possible. Practical results to watch include registration shift, edge wave, curl, shrink mark, and part-size change.

PET Film Optical Properties

Pet film optical properties should be judged by visual and inspection requirements. A film described as clear may still differ in haze, gloss, clarity, color tone, surface roughness, and defect level.

Surface Tension, Dyne Level and Corona Treatment

Surface tension shows whether the film surface can be wetted by ink, coating liquid, primer, adhesive, release coating, or functional coating. It is usually measured in dyne/cm. Untreated PET film may be suitable for non-coated use, while printing, coating, and lamination often require corona-treated or chemically treated surfaces.

COF and Web Processing Stability

COF, or coefficient of friction, measures how easily a film surface slides against another surface. Static COF relates to start-up movement. Kinetic COF relates to sliding during continuous movement. COF affects winding, unwinding, feeding, printing, coating, lamination, slitting, die cutting, stacking, and blocking.

Data-Focused TDS Reference Table

FAQ

What should a PET Film Technical Data Sheet include?

It should include density, thickness, GSM or yield, roll weight logic, MD/TD tensile strength, elongation, modulus, shrinkage, optical data, surface tension, COF, roll quality, test methods, and approval conditions.

What is the typical density of PET film?

The density of pet film is often estimated at 1.38-1.40 g/cm3 for general clear PET or BOPET film. This equals 1380-1400 kg/m3. Coated, matte, white, filled, or treated polyester film may have a different actual density.

How do I calculate PET film roll weight?

Use this formula: roll weight kg = width m x length m x thickness um x density g/cm3 x 0.001. For example, 1.0 m x 1000 m x 100 um x 1.39 x 0.001 = 139 kg before adding core, coating, liner, and packaging weight.

Why do dyne level and COF need separate checks?

Dyne level shows whether the film surface can be wetted by inks, coatings, adhesives, or primers. COF shows how the film slides during winding, unwinding, feeding, printing, coating, lamination, and die cutting. A film can have good dyne level but still run poorly if COF, flatness, or surface cleanliness is unsuitable.