Outdoor natural exposure (moderate UV, excluding tropical strong UV /coastal heavy salt spray), high-quality coil coating, solid standard colors ΔE: CIE Lab; Gloss retention = Gloss after aging ÷ Initial gloss; ΔE＞3: Color difference visible to naked eye Test standards: GB/T 17748, ASTM D2244, GB/T 9754 .
|
Years |
Coating |
Color Difference ▲E (Typical Range) |
Gloss Retention |
Visual Description |
Additional Aging Phenomenon |
| 1 year |
HDPE |
0.8~1.5 |
82%~88% |
Barely perceptible discoloration slightly darker |
No chalking |
|
PVDF |
0.4~0.9 |
90%~95% |
Virtually no visible change
|
No chalking |
|
| 2 year |
HDPE |
1.8~2.8 |
70%~78% |
Lighter colours & bright colours start to darken perceptibly |
Slight gloss loss, negligible chalking |
|
PVDF |
0.7~1.3 |
86%~92% |
Generally stable |
No chalking |
|
| 3 year |
HDPE |
2.8~4.0 |
58%~68% |
Obvious colour difference for light / yellow / red high-sensitivity colours |
Mild chalking, significant gloss fading |
|
PVDF |
1.0~1.8 |
82%~88% |
Only noticeable when closely compared with the original sample |
Basically no chalking |
|
| 4 year |
HDPE |
3.8~5.2 |
48%~58% |
Uneven shade may occur within the same batch panels |
Increased chalking, easier dirt adhesion |
|
PVDF |
1.3~2.2 |
78%~84% |
Acceptable colour consistency from a distance |
Very slight chalking (premium grade: chalking grade 0) |
|
| 5 year |
HDPE |
4.8~6.5 |
40%~50% |
Marked colour difference; contrast between old & new panels at joints is highly visible |
Moderate chalking, hazy surface, prone to soiling |
|
PVDF |
1.6~2.8 |
74%~82% |
Minor shift visible on close comparison with master sample; consistent appearance remotely |
Very slight chalking, good self-cleaning performance retained |
Key Remarks
1.Results are heavily affected by service conditions: coastal salt mist, strong UV/highland areas, bright yellow/ scarlet and other high-sensitivity pigments, thin coating, non-standard coil coating and low-grade polyester will push AE of HDPE polyester panels to 7~ 9 within 5 years, accompanied by severe gloss loss. For PVDF products blended with only 30% PVDF resin, performance degrades sharply and approaches that of high-performance polyester.
2. Standard threshold reference: After 4oooh accelerated ageing test (equivalent to approx. 3-5 years outdoor exposure) per GB/T 17748, the pass requirement is AE$4.0; the commonly accepted upper limit for natural exposure 5-year project acceptance is AE ≤5.0.
3.Warranty practice: Manufacturers generally only provide limited 3-5 year outdoor warranty for HDPE coating. PVDF fluorocarbon normally carries 15 years facade warranty.
4. Interpretation of colour difference: AE<1.5:Undetectable by human eyes; 1.5~3.0: Detectable upon professional side-by-side comparison;>3.0:Clearly visible to ordinary observers;>5: Severe colour variation, frequent cause of project complaints.
Brief Version for Technical Datasheet
|
Item |
HDPE High-performance Polyester (5 Years Outdoor) |
70% PVDF Fluorocarbon (5 Years Outdoor) |
|
Color Change ▲E |
4.8~6.5 |
1.6~ 2.8 |
|
Gloss Retention |
40%～50% |
74%～82% |
|
Visual Performance |
Obvious fading and chalking |
Minor colour drift, uniform appearance |
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