What Is Yellowing Index?
Direct Answer
The yellowing index measures how much a material (typically hot-melt adhesive or white nonwoven) turns yellow over time or under heat.
Key Takeaways
- The yellowing index measures how much a material (typically hot-melt adhesive or white nonwoven) turns yellow over time or under heat.
- How it works: Samples are measured against a whiteness standard before and after aging or heating; the delta is expressed as a yellowing index number.
- Qualifying adhesives for white backsheets
- Yellowing only affects looks — it can also signal adhesive degradation under heat
How Yellowing Index Works
Samples are measured against a whiteness standard before and after aging or heating; the delta is expressed as a yellowing index number. Low values mean the adhesive or material stays white, which matters for visible product appearance.
Examples and Applications
- Qualifying adhesives for white backsheets
- Aging tests on clear films
Yellowing Index vs. Related Terms
| Term | What it is | Key difference |
|---|---|---|
| Yellowing Index | ||
| Yellowing Index |
Limitations and Common Misconceptions
- Yellowing only affects looks — it can also signal adhesive degradation under heat
Why does yellowing matter in hygiene products?
Visible yellowing on white products looks like dirt or aging; a low yellowing index keeps products looking fresh.
References
- JP CIA (industry) - Baby diaper material: key components and their functions — 行业媒体 (accessed 2026-08-02)