For distributors, installers, and OEM customers A TPU PPF can be evaluated through five major aspects: physical performance, chemical resistance, coating quality, adhesive performance, installation behavior, and aging resistance.
1.Thickness — Basic Standard High-quality PPF should meet:
• Standard TPU PPF: 7–8.5 mil (175–215 μm)
• Premium Grade: 9–10 mil (225–250 μm)
• Below 6.5 mil usually indicates inferior or downgraded material.
2.Anti-Yellowing Performance (UV Resistance) To test yellowing resistance:
• Put the TPU sample into a UV aging chamber (UVA-340)
• After 8 hours: No obvious yellowing
• After 24 hours: Slight warm tone is normal
• Quick yellowing = non-aliphatic TPU or recycled TPU
Top Coating Quality (Hydrophobic + Self-Healing + Scratch Resistance)
(1) Hydrophobic Performance (Water Contact Angle) • Qualified: 95°–110° • Premium: 110°–125°
Angles below 90° indicate weak or missing top coating.
(1) Self-Healing Test
Scratch the surface lightly with a metal key, then apply heat:
- Hot water (80–90°C) or heat gun (60–80°C)
- High-quality PPF = scratches disappear in 10–30 seconds
Poor PPF will not repair or only partially repairs.
(3) Anti-Scratch Ability Use a hard plastic scraper or 2H pencil: • Good coating: no visible marks • Poor coating: white lines that don’t recover
- Adhesive (PSA) Quality — Determines Lifting, Residue, and Durability (1) Tack Level • Should be medium–high tack • Must NOT feel overly sticky or stringy
Stringy glue = poor adhesive formulation.
(2) Residue Test
Apply film to a clean painted panel for 24 hours → then peel:
- Qualified: no glue residue, no ghost marks
- Unqualified: residue, hazing, whitening, or glue transfer
(3) Edge Lifting Test
Apply film to a complex curved area and wait 48 hours:
- Qualified: stable edges, no lifting
- Unqualified: edges raise or shrink inward
5. Stretch & Mechanical Performance
High-quality aliphatic TPU should reach:
- Tensile Strength: > 30 MPa
- Elongation at Break: > 300%
Simple manual test:
- TPU: soft, stretchy, and does not whiten when pulled
- TPE/PVC: stiff, whitens or tears easily
6. Scratch Resistance (Hardness / Abrasion)
Quick test:
- Use a 2H pencil at 45°
- Qualified: no visible scratches
- Poor film: instant damage
Professional lab test:
- Taber Abrasion (1000g, 1000 cycles)
Premium TPU shows very low wear.
7. Shrinkage Test (Dimensional Stability)
Apply film to a flat board (20×20 cm), mark edges, leave for 72 hours:
- Qualified: ≤ 1 mm shrinkage
- Medium quality: 1–3 mm
- Low-end TPU: 3–6 mm
More shrinkage = unstable base material.
8. Quick On-Site Tests (30 Minutes, No Instruments Needed)
(1) Hot Water Self-Healing Test
Pour 80°C hot water → surface scratches should heal.
(2) Peel Test
Check for whitening, glue strings, and residue.
Residue = fail.
(3) Burn Test (Edge Only!)
Use a lighter on the edge for 1–2 seconds:
- TPU: curls slightly, minimal smoke
- PVC/TPE: black smoke, bad smell, dripping
(4) Manual Stretch Test
TPU = flexible and elastic
PVC/TPE = stiff, white lines appear
Common characteristics of substandard TPU paint protection film indicate poor quality if any of the following occur:
• Yellowing within weeks
• Surface easily attracts dirt
• Whitening when stretched
• Peeling at complex curves
• Orange peel texture after heating
• Residue left upon removal
• No self-healing capability or weak self-healing effect
• Deformation or shrinkage under sunlight
If 2-3 characteristics appear simultaneously → High likelihood of inferior or counterfeit TPU
Translated with DeepL.com (free version)
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