Solvent Red 24 / Solvent Dyes
Solvent Dyes
Technical Information
Bright Scarlet Red Solvent Dye for Plastics, Fuels & Industrial Coloration
Solvent Red 24 (CAS 85-83-6) is a high-performance scarlet red oil-soluble dye engineered for demanding industrial coloration applications. With a melting point of 165–170°C and heat resistance rated to 250°C in PS, ABS, SAN, and PMMA, this dye delivers consistent vivid red shades even under high-temperature processing conditions such as injection molding and extrusion. Its light fastness rating of 5–6 (Blue Wool Scale) ensures reliable color retention in both indoor and semi-exposed end-use environments.
Unlike many azo-based solvent dyes, Solvent Red 24 exhibits excellent migration resistance (Grade 5) across multiple polymer substrates, meaning color stays locked in the matrix without bleeding to adjacent layers — a critical requirement for multi-layer packaging, automotive interior trim, and consumer electronics housings. The dye shows outstanding solubility in aromatic solvents (37.4 g/L in toluene, 33.0 g/L in dichloromethane) and moderate solubility in alcohols (12.0 g/L in ethanol), making it versatile for both solvent-based liquid coloring and dry polymer masterbatch applications.
Compared to Solvent Red 26 (a close structural analogue), SR24 offers superior heat stability and a bluer red shade more suitable for automotive and appliance color palettes. It is widely used in fuel dyeing (gasoline, diesel marker applications), candle manufacturing, lubricant tinting, and transparent plastic components where color brilliance and thermal stability are non-negotiable.
Product specification
Appearance: Red powder — visual indicator of dye purity and particle uniformity; consistent powder form ensures accurate dosing and homogeneous dispersion in polymer melts.
Tinting Strength: 100±3% — measures the dye’s color-producing power relative to a standard reference; tight ±3% tolerance guarantees batch-to-batch shade consistency critical for large-volume production runs.
Shade Color: Similar to the standard — confirms the hue matches the certified reference under controlled D65 illumination; any deviation would signal contamination or synthesis variation.
Ash: ≤ 1.0% — low inorganic residue indicates high organic purity, reducing the risk of filter clogging in melt-spinning and thin-film extrusion processes.
Moisture: ≤ 1.0% — controlled moisture content prevents hydrolysis during high-temperature processing and avoids foaming or void formation in transparent plastic parts.
Color Differential Value (ΔE): ≤ 0.8 — maximum permissible color difference from the standard; a ΔE below 1.0 is imperceptible to the human eye, ensuring seamless color matching across shipments.
Density: 1.33 g/cm³ — relevant for volumetric dosing calculations in liquid fuel and lubricant dyeing, as well as for specific gravity matching in multi-component polymer blends.
Melting Point: 165–170°C — defines the thermal activation window; the dye must fully dissolve in the polymer melt above this range to achieve transparent, streak-free coloration.
Technical Data
| Test Items | PS | ABS | SAN | PMMA | PC | R-PVC | PA6 | PET |
| Heat resistance temperature, ℃
(0.05% dyes, transparent) |
250 | 250 | 250 | 250 | – | – | – | – |
| Heat resistance temperature, ℃
(0.05% dyes + 1.0% Titanium dioxide) |
250 | 250 | 250 | 250 | – | – | – | – |
| Migration resistance | 5 | 5 | 5 | 5 | – | 5 | 5 | – |
| Light fastness (0.05% dyes, transparent) | 5-6 | 5-6 | – | – | – | 5-6 | – | |
| Weather resistance | – | – | – | – | – | – | – | – |
| Acid resistance (in 5% hydrochloric acid solution) | – | – | – | – | – | 5 | – | – |
| Alkali resistance (in 5% caustic soda solution) | – | – | – | – | – | 5 | – | – |
Solvent Red 24 solubility in organic solvent at 20℃(g/l)
| Acetone | Butyl Acetate | Methylbenzene | Dichloromethane | Ethylalcohol |
| 20.2 | 21.7 | 37.4 | 33.0 | 12.0 |
Solubility interpretation: The highest solubility in toluene (37.4 g/L) and dichloromethane (33.0 g/L) makes SR24 ideal for aromatic and chlorinated solvent-based liquid dye systems. Moderate acetone and butyl acetate solubility (20–22 g/L) supports use in general-purpose solvent blends. Lower ethanol solubility (12.0 g/L) means pre-dissolution in stronger solvents is recommended for alcohol-based formulations.
Application Profile
| PS | ● | PET | ● | PC | – |
| AS | – | PVC-R | ● | SAN | ○ |
| ABS | ○ | PVC-U | ● | HIPS | ○ |
| PMMA | ● |
Note: ● = recommended ○ = potential use – = not recommended
Recommended Dosage
Transparent: 0.025%
Non-transparent: 0.05%
Packaging:
Regular Packaging is in 25kgs paper drum, 450kgs/Pallet.
Why Choose Honor Pigments?
- 🌍 Global Export Expertise — Trusted by customers in 40+ countries for consistent quality and reliable supply
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- 🧪 Technical Support — Free color matching, formulation advice and sample testing before bulk order
📩 Need more details?
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Frequently Asked Questions — Solvent Red 24
What is Solvent Red 24 used for and which polymers are compatible?
Solvent Red 24 is a scarlet red oil-soluble dye primarily used for coloring transparent and opaque plastic components in polystyrene (PS), ABS, SAN, PMMA, PVC, and PET. It is also widely applied in fuel dyeing (gasoline and diesel marking), lubricant tinting, candle manufacturing, and rubber coloration. The dye achieves Grade 5 migration resistance in PS, ABS, and PMMA, making it suitable for multi-layer co-extruded packaging and automotive interior parts where color bleed must be prevented.
How does Solvent Red 24 compare to Solvent Red 26 in heat resistance and shade?
Solvent Red 24 offers heat resistance up to 250°C in PS, ABS, SAN, and PMMA, compared to Solvent Red 26 which is typically rated 20–30°C lower depending on substrate. SR24 delivers a bluer (scarlet) red shade ideal for automotive and appliance applications, while SR26 tends toward a yellower red. Both share similar solubility profiles, but SR24’s higher melting point (165–170°C vs. ~150°C) provides a wider processing window for high-temperature injection molding and extrusion operations.
What is the recommended dosage of Solvent Red 24 for transparent vs. opaque applications?
For transparent coloration, the recommended dosage is 0.025% by weight of substrate. For opaque (titanium dioxide-containing) systems, increase to 0.05%. These dosages are calibrated for 0.05% dye concentration used in technical testing. In fuel and lubricant dyeing, typical concentrations range from 5–50 ppm depending on the required color intensity and regulatory marking standards. Pre-dissolving the dye in a compatible solvent (toluene or dichloromethane) before addition ensures uniform distribution.
How does Honor Pigments ensure batch-to-batch consistency for Solvent Red 24?
Every batch of Solvent Red 24 undergoes six-point quality verification: tinting strength (100±3%), shade matching (ΔE ≤ 0.8 under D65 illumination), ash content (≤1.0%), moisture content (≤1.0%), density verification, and melting point confirmation. All results are documented per ISO 9001 procedures and retained for 3 years. Batch records include spectrophotometer curves, enabling exact shade reproduction for repeat orders. Customers receive a Certificate of Analysis (COA) with each shipment.