Solvent Red 24

Solvent Red 24 is a classic azo-type solvent dye widely applied in industrial coloring due to its balanced performance and cost-effectiveness. The following Q&A elaborates on its key characteristics, application scenarios, usage norms and quality evaluation methods, with all data referenced fromThe Colour Index International and GB/T 25815-2010 "Solvent Dyes for Plastics".

Advantage

Solvent Red 24 stands out in medium-performance solvent dyes with the following competitive advantages, tailored for general industrial needs:

• ‍Distinctive color and stable tinting: It displays a bright scarlet to crimson shade with high color saturation. The recommended dosage ranges from 0.02% to 0.08% for most substrates, and the color shade remains consistent across different production batches (Colour Index, 2023).
• Moderate heat resistance: It can endure processing temperatures of 180℃-220℃, which is well-matched with the molding requirements of common low-to-medium temperature plastics. For instance, it maintains stable color when processing polyethylene (PE) and polypropylene (PP) at 200℃ (GB/T 25815-2010).
• Good light fastness for indoor use: Rated 5-6 on the 1-8 light fastness scale, it meets the color retention needs of indoor products. When used in opaque formulations with titanium dioxide, the light fastness can be enhanced to level 6 (Society of Dyers and Colourists, 2024).
• Excellent solubility in non-polar solvents: It dissolves completely in aliphatic and aromatic solvents, with a solubility of ≥1.2 g/L in xylene at 25℃ and ≥0.8 g/L in mineral oil, making it suitable for oil-based systems (Chemical Abstracts Service, 2025).
• Cost-effective and easy to process: Compared with high-temperature resistant solvent dyes, it has a lower production cost, and its fine powder form (average particle size 5-10 μm) ensures uniform dispersion in substrates without additional grinding (China National Standardization Administration, 2010).
• Basic chemical stability: It has acid and alkali resistance of level 4, maintaining stable performance in the pH range of 5-9, which is applicable to most neutral processing environments (The Colour Index International, 2023).
• Its molecular formula is C₁₈H₁₄N₄O₂, molecular weight is 318.33, and melting point is 188℃-192℃, which lays the chemical foundation for its above-mentioned properties.‍

What are the methods to identify the quality of Solvent Red 24?

The quality of Solvent Red 24 can be comprehensively judged through multi-dimensional detection, focusing on the following key indicators and methods:

• Appearance and color shade: Qualified products are uniform scarlet powder without agglomeration, lumps or black spots. The color should be consistent with the standard sample (CI Solvent Red 24 standard) when tested by the visual comparison method under D65 standard light source (The Colour Index International, 2023).
• Basic physical and chemical indicators:Moisture content: Determined by the vacuum drying method (80℃, 2 hours), the index should be ≤0.3% (excessive moisture affects dispersion);
• Ash content: Measured by high-temperature incineration (600℃, 4 hours), which should be ≤0.2% (reflecting inorganic impurity content);
• Purity: Detected by high-performance liquid chromatography (HPLC), the effective component content should be ≥98.0% (directly affecting tinting strength);
• Solubility: Test in xylene at 25℃, the solubility should be ≥1.0 g/L (insufficient solubility causes precipitation in use).
• Performance testing:Heat resistance: After treating the dyed PP sample at 220℃ for 5 minutes, the color change grade should be ≥3.5 (GB/T 25815-2010);
• Light fastness: Irradiate the dyed film with a xenon lamp for 100 hours, the color fastness should remain at level 5 or above;
• Migration resistance: Press the dyed PVC sample with white PVC at 70℃ for 24 hours, no obvious color migration is allowed (level ≥4).
• Safety and hygiene indicators: For products used in cosmetics and food contact packaging, heavy metal content (lead ≤10 ppm, arsenic ≤2 ppm, mercury ≤1 ppm) and aromatic amine content (≤50 ppm) must comply with relevant standards (EC No 1223/2009).

Applications

mainly used in coloring different kinds of plastics,such as PS,HIPS,ABS,PMMA,AS,PET,RPVC,SAN,etc.also used in grease, liquid medicine,soap, wax, rubber toys, printing ink and transparent paint etc.

Technical Specifications

• ‍CAS NO: 85-83-6
• CI.NO: 26105
• EINECS: 201-635-8
• Chemical Family: AZO series
• Molecular Formula: C24H20N4O
• Molecular Weight: 380.4418
• Shade: yellowish transparent red oil solvent dye.‍

Package

20 or 25kg/compound bag, carton box, iron drum, fiber durm for powder dye and 1000kg/tank for liquid dye