Polyester Film Chemical Resistance Technical Data

Establish the Test Boundary First

This technical data applies to bare BOPET, treated PET, and adhesive-backed PET protective film. It supports screening against cleaners, alcohols, oils, dilute acids or alkalis, and process residues. Grade-specific structures can be reviewed under PET film materials for electronics, while this document remains focused on defined exposure and post-exposure evaluation.

This page does not set a universal rating or service life. Every result must identify the construction, chemical, concentration, temperature, exposure mode, and duration.

Separate the Layers That Can Fail

A construction may include treatment, PET base film, primer, adhesive, liner, and protected surface. Bare PET checks cover dimensional, optical, and mechanical change; coated film also requires whitening, softening, gloss-loss, and delamination checks.

Base-film results do not cover adhesive-backed polyester film constructions. Check peel adhesion, edge lifting, adhesive transfer, and the protected surface. A non-silicone release-coated PET film also requires separate evaluation. Record the exposed side because the two faces may respond differently.

Identify the Specimen Before Comparing Data

Main Technical Data Sheet

Item	Typical Value / Reference Range	Test Method or Condition	Notes
Base film	Identified BOPET / PET grade	Material and lot record	Keep PET, PETG, and laminates separate.
Film thickness	Tested-grade or project-confirmed value	Multi-point gauge measurement	Report nominal value and tolerance.
Total thickness	Project-confirmed construction value	Multi-point measurement	Separate it from base-film thickness.
Adhesive type	Identified removable system	Construction record	Adhesive response may control the result.
Color / clarity	Grade-specific baseline	Controlled visual check	Record lighting and exposed side.
Surface treatment	Untreated, corona, primer, hard coat, or release coat	Side identification	Treatment may alter the response.
Peel adhesion	Tested-grade or project-confirmed	Controlled 90-degree or 180-degree peel	State panel, dwell, angle, and speed.
Tensile / elongation	Tested grade, MD and TD	ASTM D882 or equivalent	Compare exposed and control specimens.
Haze / transmittance	Initial value and post-exposure change	ASTM D1003 or equivalent	Relevant to clear constructions.
Exposure rating	A, B, C, NR, or NT	Defined screening using ASTM D543 principles	Do not extend a rating to untested conditions.
Dwell observation	24 h, 72 h, and 7 days	Panel and peel check	Observation points, not guarantees.

Record the Exposure, Not Only the Chemical Name

A PET film chemical resistance test is meaningful only under reproducible exposure. Record formulation, concentration, temperature, exposed side, mode, duration, cycles, rinse, recovery, specimen count, and control. Rate wipe, splash, immersion, and stressed exposure separately.

Test Methods and Conditions

Test Item	What It Checks	Suggested Method or Reference	Why It Matters	When To Request It
Immersion	Swelling, extraction, whitening, retained properties	ASTM D543 principles or internal method	Reveals changes missed by a wipe.	Wet processing or trapped liquid
Repeated wipe	Coating, print, haze, adhesive response	Fixed cloth, load, liquid, and cycles	Method variation changes results.	Frequently cleaned surfaces
Splash / recovery	Short contact followed by drying	Timed droplet or spray	Evaporation differs from immersion.	Intermittent spills or cleaning
Mass / dimensions	Absorption, extraction, shrinkage, swelling	Conditioned before-and-after measurement	Small changes affect flatness.	Precision converting
Tensile / elongation retention	Strength and ductility	ASTM D882 or equivalent, MD and TD	Embrittlement may be invisible.	Tension, bends, or demanding peel
Haze / transmittance	Whitening or optical loss	ASTM D1003 or equivalent	Instrument data improves repeatability.	Glass, displays, clear plastics
Peel / dwell	Lifting, transfer, removal-force change	Controlled peel at 24 h, 72 h, 7 days	Base-film data cannot predict adhesive behavior.	Adhesive-backed film
Stress-assisted exposure	Cracking under bend or tension	Documented project fixture	Unstressed tests can miss edge failure.	Curves, radii, stretched areas

Convert Values Into a Selection Decision

Greater thickness can improve stiffness, but not chemical compatibility. Available gauges are summarized in the PET film thickness range, while the actual thickness, treatment, and grade require testing.

Read peel adhesion with the surface, pressure, dwell, angle, and speed. Low adhesion may permit liquid entry; high adhesion may raise removal force. Tensile strength shows pull resistance, while elongation shows deformation capacity.

For clear grades, post-exposure haze and transmittance change matter more than one initial value. Web tension, nip pressure, and operator method may also shift results.

Match the Test Panel to the Real Surface

Separate plain glass from coated, Low-E, printed, or contaminated glass. Use different panels for bare and painted metal because oil, coating cure, roughness, and gloss affect wet-out and removal.

PMMA, PC, PETG, PVC, and other plastics differ in surface energy, additives, and stress. A liquid may leave PET unchanged but attack the protected surface. Rough or low-energy surfaces may cause bubbles, channels, or lifting.

Use a Three-Interval Sample Peel Check

Apply actual-roll samples to a representative surface with controlled pressure and temperature. Keep an unexposed control and use the production concentration. Match the intended coating, slitting, and application format described in the PET film coating and testing capabilities.

At 24 h, inspect wet-out, bubbles, lifting, and initial peel. At 72 h, check curl, gloss, haze, adhesive trace, and removal-force change. At 7 days, repeat the peel and inspect tearing, cohesive failure, residue, coating interaction, and surface shadow.

Use one peel angle and speed, compare exposed specimens with controls, and document the surface before peel and after recovery.

When a Data Mismatch Turns Into Failure

Common Data Mismatch and Failure Risk

Data Point	If Too Low	If Too High	Risk in Application	Check Before Full Use
Film thickness	Wrinkling or tearing	Poor conformability	Trapped liquid, edge stress, difficult removal	Geometry, edge radius, web tension
Peel adhesion	Lifting and liquid entry	High removal force	Transfer, coating disturbance, tearing	Actual surface at each dwell
Tensile strength	Processing or peel tears	May mask low ductility	Fragmented removal	MD / TD retention
Elongation	Brittle response	Distortion under stretch	Cracking, necking, uneven peel	Retained elongation and strain
Haze	Unexpected drop may indicate specimen or measurement mismatch	Reduced clarity	Clouding or inconsistent optical appearance	Conditioned before-and-after instrument values
Surface treatment	Poor wetting	Over-treatment or unstable aged surface	Print, primer, adhesive, coating failure	Treated side, dyne status, storage age
Exposure time	Cumulative change missed	Duty overstated	False approval or rejection	Contact, dwell, recovery
Application pressure	Incomplete wet-out	Imprint or trapped liquid	Bubbles, lifting, marking	Equipment and operator method

Protect the Reference Condition During Storage

Keep rolls in original packaging in a clean, dry area. Avoid solvent vapor, sunlight, edge impact, leaning stacks, and excessive roll pressure. Record storage history and re-test damaged or visibly distorted rolls.

Frequently Asked Questions

What does a typical value mean in a technical data sheet?

It is a representative result for an identified grade and condition, not a guaranteed limit. Final acceptance requires a confirmed value and sample result.

What factors change polyester film chemical resistance?

Key variables include construction, concentration, temperature, contact time, stress, and method. Coatings, adhesives, sunlight, and storage history may add effects.

Is PET film resistant to alcohol and isopropyl alcohol?

Not automatically. Test the actual alcohol concentration and cycles on the complete construction, then check optical change, peel behavior, and the protected surface.

Is peel adhesion enough to confirm removal performance?

No. Also check edge lifting, adhesive transfer, tearing, surface shadow, dwell time, and the protected coating.