Common Causes of Fabric Yellowing and How to Prevent Them？

— Effective Solutions for pH Yellowing, Phenolic Yellowing, and Additive-Induced Yellowing

Yellowing of white or light-colored fabrics during storage, transportation, or use is a common yet critical issue in textile finishing. It not only compromises product appearance but can also lead to customer complaints or returns. Below, we outline the most common types of yellowing, their causes, and effective prevention strategies — including the introduction of our anti-yellowing solution Sylic FU5610 (CY-737).

1. pH-Induced Yellowing

When the fabric’s pH is too alkaline or uneven across the surface, yellowing can occur—especially in white or fluorescent-brightened fabrics, which are more sensitive to pH changes. Residual alkali that hasn’t been properly neutralized can lead to localized yellowing during moisture evaporation or long-term storage.

Solutions:

• Ensure thorough neutralization and rinsing after finishing;

• Use non-volatile organic acids (e.g., lactic acid) instead of volatile ones like acetic acid;

• Note that commonly used citric acid, though non-volatile, can also contribute to yellowing risks and should be used cautiously.

2. Additive-Induced Yellowing

Cationic softeners and other finishing additives can cause yellowing, particularly on light-colored or white fabrics. Yellowing from additives can occur:

• Immediately after application, or

• Over time, during storage or transportation (the latter being more difficult to detect in advance).

Solutions:

• Always test the yellowing potential of finishing agents on light fabrics before production;

• Avoid additives that are unstable under light, heat, or exposure to air.

3. Oxidation Yellowing

Fibers such as nylon, polyester, and wool are prone to oxidation yellowing during high-temperature setting, prolonged exposure to sunlight, or long-term storage. This type of yellowing is related to the inherent chemical structure of the fiber.

Solutions:

• Apply antioxidants during processing;

• Store fabrics in cool, dry environments, away from direct sunlight.

4. Phenolic Yellowing

Phenolic yellowing occurs mostly in nylon fabrics, caused by a chemical reaction between the antioxidant BHT (2,6-di-tert-butyl-4-methylphenol)—commonly found in packaging materials—and nitrogen oxides in the air. This reaction leads to yellow stains on the fabric surface.

Solutions:

• Apply anti-phenolic yellowing agents;

• Avoid packaging materials containing BHT;

• Conduct yellowing sensitivity tests using international standards:

• ISO 105-X18:2007 (Textiles — Phenolic Yellowing Fastness)

• GB/T 29778-2013 (Testing for Potential Phenolic Yellowing in Textiles)

Recommended Solution: Sylic FU5610 (CY-737)

Sylic FU5610 Antiyellowing Agent (CY-737) is specially developed to prevent phenolic yellowing and other types of yellowing in nylon and blended fabrics.

• Appearance: Yellow transparent liquid

• pH (1% aqueous solution): 2.5 – 4.5

• Ionic character: Anionic

• Suitable for: Various fabrics, especially nylon and nylon blends

• Functions:

• Effectively prevents phenolic yellowing during packaging, transportation, and storage

• Enhances overall yellowing stability of finished fabrics

Application Guidelines:

• Padding method: 10–30 g/L

• Exhaust method: 1–3% (based on fabric weight)

For technical data sheets or sample requests, please contact us at:
info@sylicglobal.com