UV resistance measures how a material holds up to ultraviolet radiation — sunlight, mostly. PLA bioplastic is moderately UV-sensitive: prolonged direct sun exposure (months) causes surface yellowing and slight brittleness. For drawer organisers, the question is mostly academic because drawers are closed; for the rare exception, it's worth knowing.
Why drawers don't see UV
The simple story: a closed drawer is a sealed box with no natural light. Modu Drawer modules sit in the dark for the vast majority of their lifetime. UV resistance is irrelevant to the standard kitchen-drawer use case — the module never sees the sun.
When UV starts to matter
- Drawers that stay open. If a drawer in a sunlit kitchen stays open for hours daily (rare but happens), the contents-facing modules see UV.
- Open-top storage adjacent to a window. Some households use Modu Drawer modules outside drawers — bedroom-vanity organisation on an exposed surface, for example. Months of direct sunlight on an open module can cause a faint yellowing.
- Long-term storage in a sunny attic. Modules stored unused on a sunny shelf for a year+ can yellow even unboxed.
The structural impact
UV degradation is gradual:
- Months 0–3 in direct sun: barely visible. No structural change.
- Months 3–12: faint surface yellowing. Slight loss of impact strength but still functional.
- Years 1+: visible yellowing, brittleness near surface, structural weakening.
None of this happens inside a closed drawer.
UV-sensitive PLA vs UV-resistant filaments
Some 3D-printing filaments are blended with UV stabilisers (TiO₂ pigments, HALS additives) for outdoor use. Modu Drawer's PLA is the standard food-grade variant — optimised for food-contact safety, not UV outdoor durability. The trade-off is intentional: food-grade certification means fewer additives in the polymer.
Practical advice
If you plan to use Modu Drawer modules outside a closed drawer in a sunlit space, expect cosmetic yellowing over years. The structural fit and snap-lock are unaffected; the colour shift is gradual and even.