Yellowing is one of the most critical issues for transparent phone cases.
But in practise projects, what matters is not whether yellowing occurs — but how quickly it happens.
To evaluate performance,we alwayse proceed UV accelerated testing to verify case Anti-yellow charactor. we recently conducted a controlled UV Accelarated exposure test in a certified lab, comparing:
• Sendtin anti-yellow Clear PC+TPU case
• A competitor’s clear PC+ TPU case (provided by a European client)
Test Standard
The test was conducted according to ISO 4892-3 (UV accelerated aging) under the following conditions:
• 72 hours UV exposure
• 60°C environment
• UVA-351 lamp
• Color measured every 24 hours
Evaluation standard:
ΔE (color difference before and after test) must be less than 2 to pass.
Test Results (Clear Comparison)
Competitor Sample
• Failed after 24 hours
• ΔE exceeded 6 after full test
• Visible yellowing and color change
Sendtin Sample
• Passed full 72-hour test
• ΔE remained below 2
• Only slight color change, no obvious yellowing.
What This Means
The difference is not small — it’s fundamental.
A ΔE > 6 means obvious discoloration visible to the naked eye.
A ΔE < 2 means minimal change, maintaining a clean and premium appearance.
For brands, this directly affects:
• Customer perception
• Product lifespan
• Return rates
Why Some TPU Cases Fail Early
From our engineering experience, most failures come from:
• Low-grade TPU materials
• Lack of UV protection
• No surface coating process
Even if the product looks good initially, performance degrades quickly under real usage conditions.
Our Approach
To improve anti-yellowing performance, we focus on:
Material selection
Using high-grade anti-yellow TPU with better UV resistance
Surface protection
Applying coating to reduce environmental exposure
This combination ensures stable performance under both lab testing and real-life use.
Proven by Testing, Not Just Claims
This was not a theoretical comparison — it was based on real samples from an actual project.
The results clearly show how material and process choices directly impact product quality.
Facing Similar Issues?
If your current phone cases fail UV tests or show early yellowing, we can help you evaluate and improve both materials and production processes.
