Challenge
White and light-colored appliance housings looked acceptable after molding, but the buyer needed to reduce delayed yellowing risk after shipment and storage. The project required separating surface contamination from true bulk yellowing inside the material system.
Material Solution
The review focused on ABS and PC/ABS resin selection, color masterbatch, rutile titanium dioxide, antioxidant package, UV stabilization, recycled content control, drying quality and processing heat history. The goal was to prevent yellowing at formula level instead of only adjusting molding parameters.
Key Engineering Controls
- Surface yellowing and bulk yellowing should be diagnosed separately before changing the material.
- Rutile titanium dioxide is preferred when white appliance parts require stronger UV shielding.
- Antioxidant and UV stabilizer systems should be specified together with recycled-content limits.
- PC drying quality and excessive barrel temperature must be reviewed to reduce latent yellowing risk.
Outcome
The customer received a practical formula-review checklist before batch production, helping the team identify whether yellowing risk came from contamination, resin degradation, TiO2 selection, recycled content or insufficient stabilization.