Shandong Huashang Chemical Co., Ltd. is a high-tech enterprise specializing in the research and development, manufacturing, and sales of fine chemicals. Headquartered in Jinan, Shandong, China, we are committed to delivering high-quality products to our global partners. Currently, over 90% of our products are exported to developed markets, including North America, Europe, Japan, South Korea, and the Middle East.
Product Description
Pigment Red 170 (CAS: 2786-76-7), also known as Permanent Red F2RK/F5RK or Naphthol Red, is a high-performance monoazo organic pigment belonging to the naphthol AS derivative class. It presents as a bright yellowish-red to bluish-red powder with two main crystal forms: transparent type (bluish-red, lightfastness Grade 5–6) and non-transparent type (neutral red, high hiding power, lightfastness Grade 7). Characterized by vibrant color, high gloss, strong tinting strength, and excellent dispersion, it is insoluble in water and common organic solvents, with good resistance to light, heat, and solvents. Industrially, it is synthesized via diazotization of p-aminobenzamide followed by coupling with 3-hydroxy-2-naphthoic acid (2-ethoxy)anilide (Naphtol AS-PH precursor). As a versatile red pigment, it is widely used in coatings, inks, plastics, and textile printing.
Uses
Coatings Industry: Ideal for industrial paints, automotive OEM coatings and refinishes, coil coatings, powder coatings, and decorative water-based/solvent-based paints. It can be blended with molybdate orange or quinacridone for color matching, offering excellent weatherability and gloss retention.
Inks Industry: Suitable for offset inks, water-based inks, solvent-based inks, metal decorative inks, and UV inks. Its high tinting strength (only 0.22% dosage for 1% TiO? shading in HDPE) and good printability make it popular in packaging and commercial printing.
Plastics & Polymers: Used for mass coloration of polyolefins (PE, PP), PVC, ABS, and engineering plastics. It withstands processing temperatures up to 180°C without decomposition, providing uniform color and migration resistance.
Textile & Other Applications: Applied in textile printing, dyeing of viscose fibers, wood coloring, and leather finishing. Also used in rubber, paper, and synthetic leather for its good fastness properties.
Molecular Formula & Structure
- Molecular Formula: C??H??N?O?
- Molecular Weight: 454.48 g/mol
- IUPAC Name: 4-[[4-(Aminocarbonyl)phenyl]azo]-N-(2-ethoxyphenyl)-3-hydroxy-2-naphthalenecarboxamide
- Synonyms: Permanent Red F2RK/F5RK; Naphthol Red; C.I. Pigment Red 170; C.I. 12475; Fast Red F2RK; MFCD00281164; EINECS 220-509-3
- CAS Number: 2786-76-7
- SMILES Code: CCOc1ccccc1NC(=O)c2ccc3ccccc3c2(O)N=Nc4ccc(C(N)=O)cc4
- Chemical Structure: A monoazo pigment with a naphthol AS core, featuring an azo group (-N=N-) linking a 4-carbamoylphenyl diazo component and a 3-hydroxy-2-naphthanilide coupling component (2-ethoxyphenylamide). Exists as hydrazo tautomer in solid state with α and φ polymorphs; φ-form is denser, more stable, and produced industrially via hydrothermal treatment.
Physical & Chemical Properties
- Appearance: Bright yellowish-red to bluish-red fine powder; odorless; two crystal forms (transparent/non-transparent).
- Melting Point: 315–325°C (decomposition); Boiling Point: 663.2±55.0°C (predicted); Density: 1.31–1.40 g/cm3 (25°C).
- Particle Size: 0.18–0.22 μm (rod-shaped); Specific Surface Area: 22–26 m2/g; Oil Absorption: 45–81 g/100g; pH (10% slurry): 6.0–7.0.
- Solubility: Insoluble in water, ethanol, acetone, ether, and most organic solvents; slightly soluble in hot dilute acids; resistant to migration in polymers.
- Stability: Stable under normal temperature and pressure; resistant to light (Grade 5–7), heat (up to 180°C), water, oil, acid, and alkali; incompatible with strong oxidizing agents; avoid prolonged exposure to high humidity.
- Toxicity & Safety: Low acute toxicity; oral LD?? (rats) >5000 mg/kg; non-irritating to skin and eyes; no known carcinogenic or mutagenic effects. GHS Labeling: Not classified as hazardous; no hazard statements required.
Synthesis & Storage
- Synthesis: Two-step process: (1) Diazotization: p-aminobenzamide reacts with sodium nitrite in acidic conditions to form diazonium salt. (2) Coupling: Diazonium salt couples with 3-hydroxy-2-naphthoic acid (2-ethoxy)anilide (Naphtol AS-PH) under alkaline conditions. The crude pigment is filtered, washed, dried, and milled; φ-polymorph is obtained by heating in water at 130°C under pressure for enhanced stability.
- Storage: Store in a cool, dry, well-ventilated warehouse at ≤25°C; keep containers tightly sealed to prevent moisture absorption and contamination. Packed in 25kg compound bags or fiber drums. Avoid direct sunlight, high temperature (>40°C), and strong oxidizing agents; keep away from food and feed materials. Shelf life: 24 months when unopened and stored properly.
- Handling Precautions: Use in well-ventilated areas; wear dust mask, nitrile gloves, and safety goggles to avoid inhalation and skin/eye contact. In case of skin contact, rinse with plenty of water; in case of eye contact, rinse with water for 15 minutes and seek medical attention if irritation persists. Avoid generating dust; prevent release into environment. Dispose of waste in accordance with local regulations.
