EVA (ethylene-vinyl acetate) is one of the most widely used materials for shoe soles, known for its lightweight, flexible, and shock-absorbing properties. EVA shoe soles are popular across athletic, casual, and children’s footwear markets. However, many manufacturers struggle with a common challenge—yellowing and insufficient whiteness in EVA soles over time.
The solution? Incorporating a high-performance optical brightening agent (OBA) designed specifically for EVA applications. Let’s explore how OBA for EVA shoe soles can solve yellowing issues and enhance overall product quality.
Causes of Yellowing in EVA Shoe Soles
- Light Absorption Effects:
EVA shoe soles tend to contain trace colored compounds that absorb blue or blue-violet visible light (~450 nm), making the material appear yellowish. - UV Degradation:
Prolonged exposure to ultraviolet (UV) light can break down molecular bonds within EVA, reducing its antioxidant stability and causing irreversible yellowing.
How OBA for EVA Shoe Soles Works
Adding a suitable fluorescent whitening agent to EVA shoe compounds helps counteract yellow tones through optical color correction. These agents absorb invisible UV light and re-emit it as blue light, neutralizing yellow hues and creating a bright white appearance.
Usage method:
Before foaming, add 0.03%–0.05% of the fluorescent whitening agent evenly into the raw EVA mixture with other additives. The OBA disperses uniformly, improving both whiteness and anti-yellowing stability.
Why Choose KCB as the Optimal OBA for EVA Shoe Soles
Among various whitening agents, fluorescent brightener KCB stands out for EVA foaming applications due to its superior stability, thermal resistance, and bluish-white effect.
1️⃣ Excellent Stability
KCB shows strong migration resistance and maintains brightness longer than conventional brighteners like OB-1 or 127, minimizing post-production yellowing.
2️⃣ Perfect Temperature Resistance
EVA foaming typically occurs between 210–230°C. Many whitening agents degrade at this range, but KCB withstands up to 220°C, performing optimally during EVA production without decomposition.
3️⃣ Attractive Bluish-White Tone
Consumers prefer a clean, bluish-white hue over dull white tones. KCB imparts a bright bluish-white finish that enhances the perceived quality of EVA foam soles.
4️⃣ Non-Interference with Foaming Process
The OBA does not affect bubble size or elasticity in EVA foaming. It preserves both the aesthetic and physical properties—ensuring durability, comfort, and consistent quality.
Conclusion
For manufacturers seeking to improve whiteness, brightness, and long-term durability of EVA footwear, KCB is the best-performing OBA for EVA shoe soles.
It ensures stable color performance, high-temperature tolerance, and a vibrant appearance, making EVA soles more appealing and more resistant to aging.