Buying questions
Why does white nonwoven fabric turn yellow in storage?
Yellowing is oxidation, and the culprit is usually one of four: heat, light, packaging chemistry or an additive that reacts. Finding which one takes a controlled sample test, not a guess.
At a glance
Specification at a glance
| Cause | Clue | Fix |
|---|---|---|
| Heat and time | Uniform, gradual | Cooler storage, earlier use |
| UV light | Outer layer only | Opaque packaging |
| Packaging film | Pattern follows film folds | Change film, test again |
| Metal contamination | Spots, localised | Check line and handling |
| Additive reaction | Uniform, fast | Review the additive package |
Why the pattern tells you the cause
Uniform yellowing across a roll points to heat or an additive. Yellowing only on the outside layer points to light. A pattern that follows the packaging film points to the film. Spots point to contamination, often iron, from a tool or a worn machine part.
How to test instead of argue
Store three samples under three conditions: dark and cool, dark and warm, and light. Compare after two and four weeks with a colour meter. The condition that turns yellow is the cause, and the fix follows from it.
Check the claim before it goes on the pack
Send the claim you want to make and the market it sells in. We reply with what the material can support and what it cannot.
Questions
Common questions
Does titanium dioxide cause yellowing?
It can contribute in combination with certain additives and heat, but it is also what makes the web white. The additive package and the process temperature matter more.
Is yellowed fabric unsafe?
Not necessarily, but it is out of specification for a white product and it may indicate oxidation that also changed strength.
Can it be reversed?
No. Yellowing from oxidation is permanent; optical brighteners only mask it on the surface.