Differences Between AA-Grade Polyester Filament Yarn and A-Grade Polyester Filament Yarn‌
AA-grade and A-grade polyester filament yarns differ significantly in quality tier, defect tolerance, physical properties, and application scope‌12.

Key Comparison

• ‌Surface Defects‌:
  • ‌AA-grade‌: Minimal defects; fuzz yarns ≤1–2 strands/100,000m; free of stiff filaments, oil stains, or abrasions‌14.
  • ‌A-grade‌: More fuzz yarns (5–6 strands/100,000m); may exhibit broken ends or inconsistent bobbin size‌14.
• ‌Physical & Dyeing Properties‌:
  • ‌AA-grade‌: Superior dye uniformity (grey scale rating ≥4.5); tensile strength ≥3.6–3.8 cN/dtex; low deviation in boiling water shrinkage‌45.
  • ‌A-grade‌: Moderate dye uniformity (grey scale rating ≥4); tensile strength ≥3.5 cN/dtex; higher property unevenness‌45.
• ‌Applications‌:
  • ‌AA-grade‌: Meets industry premium standards; used for high-end apparel, medical textiles, and sensitive color dyeing‌12.
  • ‌A-grade‌: Suitable for brand garments or home textiles but prone to yarn breaks or uneven dyeing during processing‌12.

Additionally, AA-grade requires compliance with both fixed length (uniform cake length) and fixed weight (consistent weight per unit) standards, while A-grade typically meets only one criterion‌3. These differences result in higher costs for AA-grade (optimized quality) versus the cost-effective A-grade for conventional textiles‌