Fiber-grade polyvinyl alcohol resin can be divided into high-alkali alcoholysis and low-alkali alcoholysis, which can be divided into three grades, namely excellent products, first-class products, and qualified products. Today, let’s introduce the regulations of GB/T7351-2013 on fiber-grade polyvinyl alcohol resin.
Item detection
1. Volatile content: High-alkali alcoholysis products must be ≤ 5.0%, first-class products ≤ 6.0%, and qualified products ≤ 7.0%; low-alkali alcoholysis products must be ≤ 6.0%, first-class products ≤ 7.0%, qualified Products ≤ 7.0%, to reach the standard.
2. Sodium hydroxide: High-alkali alcoholysis high-quality products need ≤0.20%, first-class products ≤0.20%, qualified products ≤0.30%; low-alkali alcoholysis high-quality products need ≤0.10%, first-class products ≤0.20%, Qualified product ≤ 0.30% can meet the standard.
3. Residual acetate: the high-quality products of high-alkali alcoholysis need ≤0.15%, the first-class products ≤0.20%, and the qualified products ≤0.20%; Qualified product ≤ 0.20% can meet the standard.
4. Sodium acetate: High-alkali alcoholysis high-quality products need ≤ 6.8%, first-class products ≤ 7.0%, qualified products ≤ 7.0%; low-alkali alcoholysis high-quality products need ≤ 2.0%, first-class products ≤ 2.3%, qualified Products ≤ 2.5%, to reach the standard.
5. Purity: High-alkali alcoholysis products must be ≥ 88.0%, first-class products ≥ 86.0%, and qualified products ≥ 85.0%; low-alkali alcoholysis products must be ≥ 91.5%, first-class products ≥ 90.0%, and qualified products ≥90.0% to reach the standard.
6. Transparency: High-alkali alcoholysis high-quality products need ≥92.0%, first-class products ≥92.0%, qualified products ≥92.0%; low-alkali alcoholysis high-quality products need ≥92.0%, first-class products ≥92.0%, qualified products ≥92.0% to reach the standard.
7. Coloring degree: high-alkali alcoholysis high-quality products need ≥92.0%, first-class products ≥90.0%, qualified products ≥88.0%; low-alkali alcoholysis high-quality products need ≥92.0%, first-class products ≥91.0%, qualified Products ≥ 90.0% to reach the standard.
8. Swelling degree: If the high-alkali alcoholysis is 205±15%, and the low-alkali alcoholysis is 145±15%, it is regarded as up to standard.
9. Average degree of polymerization: M±50 for superior and first-class products of high-alkali alcoholysis, and M±70 for qualified products; M±50 for excellent and first-class products of low-alkali alcoholysis, and M±50 for qualified products 70, it is considered to meet the standard.
