Pigment Yellow 191 | Permanent Yellow HGR | Permanent Yellow RP

Pigment Yellow 191
Alias: Permanent Yellow HGR; PV Fast Yellow HGR; Pigment Brilliant Yellow HGR; Permanent Yellow RP
English Name: Pigment Yellow 191
Molecular Formula: C17H13CaClN4O7S2
Molecular Weight: 524.97
CAS Registry Number: 129423-54-7
EINECS Registry Number: 403-530-4
Physical and Chemical Properties
Classification: Azo Lake
Appearance: Reddish yellow powder
Hue: Reddish yellow/Greenish yellow
Density: 7.6 g/cm³
Specific Gravity: 1.3-1.5
Specific Surface Area: 20 m²/g
pH Value (10% Slurry): 6-7
Opacity: Transparent type
Lightfastness: 7 Generally reaches grade 6–7, and can achieve grade 7–8 in high-quality systems, demonstrating excellent stability under long-term light exposure.
Heat Resistance: 280°C Withstands processing temperatures up to 300°C in HDPE (High-Density Polyethylene) without causing dimensional deformation. In polycarbonate (PC), heat resistance can reach 330°C.
Migration Resistance: 5 Exhibits excellent migration resistance in systems such as plasticized PVC, maintaining uniform coloration even at low concentrations, with minimal migration or bleeding.
Acid Resistance: 5
Alkali Resistance: 5
Weather Resistance: 5
Product Application: Features bright color, strong tinting strength, good heat resistance, excellent lightfastness, and superior migration resistance. The shade of Pigment Yellow 191 is similar to C.I. Pigment Yellow 83, with lower tinting strength but outstanding heat resistance, capable of withstanding temperatures up to 300°C in plastics such as high-density polyethylene (HDPE) without dimensional deformation. It has good lightfastness (grade 7-8); excellent migration resistance in plasticized PVC; and can endure temperatures up to 330°C in polycarbonate while resisting organic solvents. In the plastics field, it is particularly suitable for coloring various plastics including PVC, PP, PU, PS, and ABS.
Uses: Due to its strong stability, good dispersibility, and excellent heat and lightfastness, Pigment Yellow 191 is suitable for a variety of high-performance plastics and coating systems.