In fields like plastics and coatings, fluorescent whitening agent FP127 is widely used for its excellent weather resistance. However, problems related to performance and process often occur in production. Below are the core answers.
 
1. Performance Issues: How to Fix Unstable Whitening Effect & Outdoor Yellowing?
 
1. Is uneven whitening intensity (with the same dosage) a quality problem?
No. The key factors are substrate whiteness (required ≥85%, moisture <0.05%) and processing dispersion. Solution: Test the substrate before use; pre-mix FP127 with a small amount of substrate first; control processing temperature at 180-220℃ (adjust by substrate type).
2. Still yellowing outdoors? How to improve weather resistance?
FP127 alone cannot resist long-term strong UV rays; yellowing results from molecular damage. Solution: Compound FP127, antioxidant, and UV absorber at a ratio of 1:0.5:0.3; for outdoor use over 1 year, increase FP127 dosage by 10%-15% (do not overdo it to avoid fluorescence quenching).
 
2. Process Issues: How to Solve Injection Molding Precipitation & Coating Delamination?
 
1. White frost (precipitation) on the surface during injection molding?
Caused by mismatched solubility between FP127 and substrate, or overly fast cooling. For polar substrates (PVC/PET), add 0.5%-1% compatibilizer; for non-polar substrates (PP/PE), control cooling rate at 5-10℃/min.
2. Delamination or uneven whitening in water-based coatings?
FP127 powder is insoluble in water (direct addition causes delamination), and low drying temperature also leads to unevenness. Solution: First dissolve FP127 in ethanol/propylene glycol at a 3:1 ratio to make a pre-dispersed slurry, then add it to the coating; ensure film-forming temperature ≥80℃.
 
3. Compliance Issues: Safe for Food-Contact Use? How to Respond to Customer Doubts?
 
1. Does it meet standards for food-contact materials (e.g., PP boxes)?
FP127 is non-toxic, but migration must be controlled (EU: ≤0.05mg/dm²; Chinese standard: no detection). Solution: Choose food-grade FP127 (purity ≥99.5%), control dosage at 0.01%-0.03%, and prepare third-party migration test reports.
2. How to prove safety if customers worry about "fluorescence residue" affecting export?
Two points: ① FP127’s fluorescent group (benzoxazole ring) is stable below 250℃, with no shedding; ② Provide application cases (food-contact/infant products) and compliance reports.
 
4. Selection: How to Distinguish FP127 from OB-1 & KCB?
 
- Choose FP127: For outdoor weather resistance (e.g., plastic building materials, outdoor furniture); suitable for PP/PE/PVC/coatings.
- Choose OB-1: For high-temperature processed engineering plastics (280-300℃, e.g., auto parts); poor weather resistance.
- Choose KCB: For indoor high-brightness needs (e.g., home appliance casings); 15%-20% lower cost than FP127, but weaker weather resistance.
 
Summary
 
The key to solving FP127’s problems lies in "demand matching + process control". First clarify your needs (outdoor use, processing temperature, compliance requirements), then verify via small-batch tests and adjust processes (temperature control, additive addition). For complex scenarios, cooperate with suppliers for customized solutions.