Section
| HS Code | 485596 |
| Product Name | Solvent Red 8 |
| Color Index Name | C.I. Solvent Red 8 |
| Color Index Number | 12715 |
| Chemical Class | Monoazo solvent dye |
| Appearance | Red powder |
| Physical State | Solid |
| Color Shade | Red |
| Water Solubility | Insoluble |
| Organic Solvent Solubility | Soluble |
| Moisture Content | ≤ 1% |
| Ash Content | ≤ 0.5% |
| Light Fastness | Good |
| Heat Stability | Good |
| Acid Resistance | Good |
| Alkali Resistance | Good |
| Storage Conditions | Cool, dry, well-ventilated area |
| Packaging | 25 kg drum |
As an accredited Solvent Red 8 factory, we enforce strict quality protocols—every batch undergoes rigorous testing to ensure consistent efficacy and safety standards.
| Packing | Solvent Red 8 is packed in 25 kg fiber drums with inner polyethylene bags for safe storage and transport. |
| Container Loading (20′ FCL) | Solvent Red 8 loaded into a 20-foot FCL container, palletized, secured, and labeled with proper documentation for safe ocean transport. |
| Shipping | Shipping description: Solvent Red 8 is typically shipped as a non-hazardous solid dye and is not regulated for transport unless the SDS states otherwise. If supplied in a solvent, classify per that solvent’s UN/class/packing group. Use closed, labeled containers protected from moisture, heat, and sunlight. |
| Storage | Store Solvent Red 8 in a cool, dry, well-ventilated area away from direct sunlight, heat, ignition sources, and oxidizing materials. Keep containers tightly closed, properly labeled, and segregated from incompatible substances. Prevent dust generation and moisture ingress. Use spill containment and appropriate PPE; follow the SDS and local regulations. Do not store near foodstuffs or acids. |
| Shelf Life | Shelf life: typically 2–5 years when stored in a sealed container, cool, dry, and protected from light. |
Solvent Red 8 (C.I. 12715) is an azo solvent dye with solubility parameters favoring aromatic hydrocarbon, ketone, ester, and medium-chain paraffin matrices. The following application zones are restricted to industrial sectors where solvent-borne or hydrocarbon-borne tinting is established commercial practice. Each zone includes compliance verification methods, formulation loading boundaries, production-scale dispersion sequences, and terminal article categories. Published data for some high-temperature engineering resin systems is limited; no claim is extended to those matrices without documented thermal stability testing per ISO 105-A02.
Candle body tinting with Solvent Red 8 is carried out via a pre-dissolved liquid concentrate rather than dry powder to avoid undissolved particulate and color specking in the finished wax mass. EU compliance verification for azo colorants follows REACH Annex XVII Entry 43 using reductive cleavage per EN 14362-1:2017, with restricted aromatic amines quantified below 30 mg/kg; finished candle flame behavior is assessed under ASTM F2417-17 for flame height stability, and soot emission is measured under ASTM F2326-20. Typical addition mass fractions range from 0.02 wt-% to 0.15 wt-% in fully refined paraffin wax with a melt point of 58–60 °C; stearin-containing candle bodies generally accept 0.03 wt-% to 0.10 wt-%, while microcrystalline wax blends can carry up to 0.18 wt-% before exudation becomes visible at the melt surface. Production-scale melt tinting is performed in jacketed vessels with axial turbine agitation, holding wax at 75–85 °C. The dye is first dissolved in a side-stream liquid paraffin or iso-paraffin at 85–95 °C under high-shear rotor-stator dispersion at 3000–6000 rpm, then metered into the main wax melt at a rate not exceeding 0.5 wt-% min−1 to prevent localized supersaturation. The melt temperature window during dosing is maintained within ±3 °C of 80 °C in paraffin systems to avoid precipitation on cooled vessel walls. The tinted melt is passed through a 25 µm stainless steel screen before filling into molds; cooling rate is controlled at 2–4 °C min−1 by modulated air or water cooling to reduce dye migration to the crystallization front. Finished candle types include scented container candles with transparent wax depth exceeding 50 mm, taper candles, tealights, and unscented wax melts. Addition above 0.25 wt-% in stearin-rich systems has been observed in production trials to produce surface bloom within 48 h at 20 °C; use in waxes containing amine-functional fatty acid derivatives is not recommended because amine groups can shift the azo chromophore and cause spectrophotometric shade drift.
| Wax matrix | Melt hold temperature (°C) | Typical addition range (wt-%) | Primary processing risk |
|---|---|---|---|
| Fully refined paraffin wax (58–60 °C melt point) | 75–85 | 0.02–0.15 | Undissolved dye particulate if pre-dispersion solvent viscosity exceeds 10 mPa·s |
| Stearin-containing candle blend | 80–90 | 0.03–0.10 | Surface bloom above 0.12 wt-% |
| Microcrystalline wax | 85–95 | 0.05–0.18 | Plate-out on mold release surfaces above 0.20 wt-% |
Nitrocellulose lacquer bases used in solvent-borne wood stain systems can be tinted with Solvent Red 8 after a pre-dissolution step in a ketone/ester co-solvent blend. Compliance under Directive 2004/42/EC covers the VOC content of the final clear base, and flash point classification is determined by closed-cup testing per ASTM D3278-96(2011); the tinting colorant itself is verified for restricted aromatic amines under EN 14362-1:2017 as part of REACH Article 31 safety data documentation. In a 12% solids nitrocellulose lacquer base, the typical wet-lacquer addition rate is 0.20 wt-% to 0.80 wt-%, with deep mahogany shading requiring up to 1.5 wt-% when a 20 µm dry film is applied over stained wood. Production-scale incorporation uses a dissolver equipped with a cowles blade at 1200–1800 rpm; the pre-dissolved dye is first wetted at 30–40 °C for 15 min, then let down with a premixed nitrocellulose/alkyd resin solution to a final viscosity of 18–25 s DIN 53211 4 mm cup. Filtration through 10 µm bag filters precedes spray application using HVLP equipment at 1.8–2.2 bar air cap pressure. Terminal articles include furniture stains, interior joinery lacquers, decorative panel coatings, and low-gloss kitchen cabinet finishes that are not exposed to continuous UV. Exterior weathering data for this dye in thin films is limited; therefore, exterior use is not specified without xenon arc testing per ISO 105-B02 to establish a minimum blue wool rating. Amine-functional adhesion promoters are excluded from the let-down stage because they may cause precipitation or shade drift in the nitrocellulose system.
The dye solubility envelope in polyamide/nitrocellulose flexographic ink systems is controlled by the ratio of ethyl acetate to ethanol and by the acid value of the polyamide resin. Packaging inks in EU jurisdictions are assessed under EU Packaging and Packaging Waste Directive 94/62/EC Article 11 heavy metal limits of 100 mg/kg for Pb, Cd, Hg, and Cr(VI), and EuPIA Good Manufacturing Practices apply to manufacturing hygiene. Azo colorant compliance uses EN 14362-1:2017 to exclude restricted amine release above 30 mg/kg. In polyamide/nitrocellulose full-strength inks, Solvent Red 8 is typically incorporated at 2.0 wt-% to 6.0 wt-% of press-ready ink, while shading applications in overprint varnishes use 0.1 wt-% to 0.5 wt-%. A pre-dissolution stage with an ethyl acetate/ethanol 80:20 blend at 40 °C under high-shear mixing at 2000 rpm for 20 min ensures absence of undissolved particles; the solution is introduced after the polyamide resin has been fully dissolved to reduce solvent shock. Final ink viscosity is adjusted to 18–22 s Zahn cup #2. Filtration through 10 µm nylon mesh is standard before press loading on central impression flexographic presses with anilox engravings from 140 lines/cm to 200 lines/cm. Terminal products include industrial labels, PE film packaging with non-food contact print, aluminum foil lamination inks, and surface print for shrink sleeves where migration is not a direct food-contact condition. The dye is not recommended for retort pouch applications or food-contact printed substrates without a functional barrier, because migration data for the dye in polyethylene terephthalate barrier structures is limited. In alcohol-rich ink systems with water content above 5 wt-%, dye precipitation has been observed at production scale.
Solvent-borne leather finish systems for automotive-grade leather use Solvent Red 8 as a transparent shading dye in polyurethane and nitrocellulose lacquer layers. The relevant compliance framework is ZDHC MRSL 3.1 for leather chemical formulations, REACH Annex XVII Entry 43 for azo colorant amines, and EN 14362-1:2017 for detection of restricted aromatic amines in finished leather. In PU topcoat lacquers, the wet-lacquer addition is 0.10 wt-% to 0.50 wt-%; for spray basecoats with a dry-film thickness of 15–25 µm, the dye concentration in the diluted spray mix is 0.3 g/L to 1.0 g/L. The dye is pre-dissolved in butyl acetate/MEK at 40–50 °C and mixed for 30 min at 500–800 rpm before being added to the polyurethane topcoat batch. Application on production lines uses multi-rotating spray guns with 2.0 mm nozzle diameter, a drying tunnel temperature between 60 °C and 80 °C, and a residence time of 3–5 min. Terminal articles include automotive interior seat leather, footwear upper leather, upholstery leather, and leather belts. Bleed testing under ISO 105-A05 should be conducted for white or light-colored polyurethane topcoats; direct contact with plasticized PVC seating components is not recommended due to potential dye migration into the plasticizer phase.
Permanent marker inks formulated with ketone-alcohol solvent systems use the low-temperature solubility retention of Solvent Red 8 when the solvent blend is maintained above the dye crystallization threshold. Art material and stationery regulatory verification in the US relies on ASTM D4236 chronic hazard labeling; EU marker inks with potential child contact require heavy metal migration testing under EN 71-3:2019, with limits for chromium(VI), lead, cadmium, and barium. Azo colorant reductive cleavage under EN 14362-1:2017 supports REACH Annex XVII Entry 43 compliance. Total dye addition in permanent marker ink is typically 0.5 wt-% to 2.0 wt-%, with 1.5 wt-% as the upper limit for capillary flow systems because higher concentrations increase low-temperature precipitation risk. The dye is dissolved in a blend of ethanol and methyl ethyl ketone at 40 °C, then passed through a 0.45 µm membrane filter before vacuum filling into marker reservoirs. Viscosity is adjusted to 2–5 mPa·s by addition of a ketone-soluble resin at 3–6 wt-%. End products include permanent markers, industrial marking pens, artist markers, and valve-action paint-marker ink bodies. Water content above 10 wt-% causes visible dye precipitation; archival lightfastness is not provided without a UV absorber package, so the formulation is intended for general marking rather than museum-grade archival ink.
Industrial lubricating grease manufacturing uses Solvent Red 8 as a color-coding dye where visual identification of grease type and circuit is required in plant maintenance environments. Lubricant color is measured under ASTM D1500 for transparent fluids; for greases, visual comparison is performed after milling. The formulation remains subject to REACH and, where used in food-processing plants, must be excluded from incidental food-contact zones because registration for food-grade lubricant use is not established. Typical dye addition for lithium complex grease is 0.005 wt-% to 0.05 wt-% of the finished grease mass, with 0.01 wt-% sufficient to produce a clear red tint in a 2 mm grease smear under daylight viewing. The dye is pre-dissolved in mineral base oil at 60–80 °C under stirred conditions for 15 min, then metered into the hot grease after saponification and dehydration but before homogenization through a three-roll mill or high-pressure homogenizer at 200–300 bar. Terminal products include lithium complex industrial greases, calcium sulfonate greases, transparent gear oils, and metalworking fluid concentrates used for equipment color identification. High-polarity synthetic ester base stocks can reduce dye solubility and produce filter-plugging particulate; trials in polyalphaolefin base oils at addition levels above 0.08 wt-% have shown precipitation during cold storage at −10 °C. Use in hydraulic fluids with acid number above 0.5 mg KOH/g is not recommended without solubility stability testing.
Competitive Solvent Red 8 prices that fit your budget—flexible terms and customized quotes for every order.
For samples, pricing, or more information, please contact us at +8615365186327 or mail to sales3@liwei-chem.com.
We will respond to you as soon as possible.
Tel: +8615365186327
Email: sales3@liwei-chem.com
Flexible payment, competitive price, premium service - Inquire now!
Solvent Red 8, referenced in the Colour Index as C.I. 12715 and registered under CAS 33239-19-9, is a monoazo solvent dye supplied as a dark red to bluish-red powder. No unified industrial model designation exists outside supplier-specific trade codes; the product is procured under the generic Colour Index name, a supplier certificate of analysis, and an end-use specification. The colorant is used in transparent styrenic and acrylic molded articles, solvent-borne wood lacquers, printing inks, and non-food-contact masterbatches. It is not approved under U.S. FDA 21 CFR for food-contact polymers. In comparison with high-performance anthraquinone reds, Solvent Red 8 is positioned as a lower-cost, higher-solubility red, but its thermal and photolytic boundaries are more constrained. The dye should not be combined with strong reducing agents or bleach systems because reductive cleavage of the azo chromophore destroys color and can generate undesirable aromatic amine fragments under specific conditions.
The primary commercial advantage of Solvent Red 8 is its rapid molecular dissolution in non-aqueous binders and styrenic melts. Its primary limitations are moderate lightfastness, shade drift at elevated melt temperatures, and migration in polyolefins. These boundaries make it suitable for internal consumer goods, packaging-neutral decorative parts, and solvent-borne indirect applications, but unsuitable for exterior automotive coatings, architectural glazing, or food-contact layers without specific regulatory and UV-stability validation.
Commercial lots are dark red to violet-red powders. Tamped bulk density tested by ISO 787-11 typically falls between 0.40 g/cm³ and 0.65 g/cm³; anti-dusting granulation or grinding pre-treatment can shift the value outside this range. Moisture content is measured by Karl Fischer titration according to ISO 15512:2019. For melt-compounding use, buyers often impose a maximum of 0.5 wt% to avoid hydrolysis and dosing drift; liquid ink applications may accept 1.0 wt%. Residue on a 45 µm sieve, determined by a wet-screening procedure adapted from ISO 787-7, is typically specified as ≤0.1 wt% for high-clarity coating solutions. Color strength is evaluated spectrophotometrically in toluene at the absorption maximum; a tolerance of ±3% relative to a retained standard is common in supplier contracts using ASTM D2244 for color difference and CIE L*a*b* coordinates.
| Parameter | Test method | Typical acceptance limit | Application-critical note |
|---|---|---|---|
| Colour Index / CAS | SDC/AATCC Colour Index, CAS Registry | C.I. 12715 / CAS 33239-19-9 | Must match purchase specification |
| Appearance | Visual comparison under D65 light | Red to violet-red powder | No visible shade or particle shift |
| Moisture | ISO 15512:2019 | ≤ 0.5 wt% for polymer melt use | Higher moisture can cause caking and dosing errors |
| Residue on 45 µm sieve | ISO 787-7 adaptation | ≤ 0.1 wt% | Controls undissolved aggregates in inks |
| Heavy metals | IEC 62321 series | RoHS Annex II limits | Lead ≤1000 mg/kg; cadmium ≤100 mg/kg |
| Tinctorial strength | ASTM D2244 in toluene solution | ±3% versus standard | Affects final mass tone and transparency |
The heavy-metal row is not a statement of intrinsic purity; it is a purchasing requirement. Because Solvent Red 8 is an azo compound, reductive cleavage can generate aromatic amines. For finished textile and leather articles in the European Union, the restriction framework is REACH Annex XVII Entry 43 with analytical testing according to DIN EN 14362-1. For polymer-soluble dyes, the extraction procedure must be validated because direct application of textile methods can produce false negatives. Processor lot-screening should also include a heat-stability tube test under nitrogen; a well-stabilized lot should retain consistent absorbance after 30 min at 230 °C. Published acceptance values for this dye under that exact test configuration are limited, so the tube method should be used to compare incoming lots against a qualified internal standard rather than as a formal product specification.
In comparison with Solvent Red 1, Solvent Red 8 generally produces a bluer mass tone and exhibits better thermal resistance in styrenic melts; however, Solvent Red 1 has a longer history in hydrocarbon fuels and waxes because of its simpler solubility behavior. Solvent Red 23 is more orange and has lower lightfastness, making it less suitable for transparent molded parts. Solvent Red 135, an anthraquinone type, offers substantially higher heat stability and lightfastness in engineering resins, but at a higher cost and with lower tinting strength per unit mass in some styrenic systems. For a styrenic molding application requiring short residence time and moderate colorfastness, Solvent Red 8 is selected because it dissolves rapidly and gives high transparency. When the same part is exposed to exterior UV or extended heat cycles above 250 °C, a shift to Solvent Red 135 or another anthraquinone red is required. Quantitative comparison must be performed in the same carrier resin, because shade and fastness shift with polymer matrix, additive package, and processing conditions.
Injection molders using transparent ABS observe that Solvent Red 8 remains visually stable when barrel profiles stay within 210–230 °C and shot-to-shot residence time is kept below 2 min. When the melt temperature reaches 240 °C or higher, shade drift toward a yellow-red occurs before gross decomposition. This drift is accelerated by shear energy in the check ring and hot-runner manifold, and by residual acidic monomers in ABS. Published kinetic data for this exact configuration is limited; therefore, the 230 °C boundary should be treated as a production-qualified guideline, not an absolute decomposition onset. Molding shops operating 400 ton hydraulic machines with 50 mm barrel diameter and long cycles should evaluate the colorant at maximum residence time, not at nominal barrel set point. If the part is sprayed with a clear UV-curable topcoat, compatibility between the cured topcoat and the dye should be tested by adhesion cross-cut after 24 h to detect dye migration into the interface.
The conventional stabilizer package in ABS also affects color stability. Zinc stearate and amine-type heat stabilizers can accelerate azo bond scission in Solvent Red 8. Zinc-free or phenolic-phosphite stabilizer systems reduce the rate of shade shift in production trials. The dye should not be compounded with strong alkaline fillers; pH above 9 in an aqueous pre-dispersion can cause hydrolysis of the chromophore. Drying of the polymer is separate from dye stability; ABS feedstock should be dried to the resin manufacturer's specification, typically below 0.1 wt% moisture, before addition of the dye at the feed throat.
If a production line uses a co-rotating twin-screw extruder with L/D ratio 44:1 and vacuum venting, Solvent Red 8 is best metered into the feed throat with the base resin, not into a side feeder after melting. Feed-throat addition extends residence time but produces a more homogeneous diffusion of dye into the polymer. A practical operating window for polystyrene masterbatch on a 40 mm machine is melt temperature 180–220 °C, screw speed 300–600 min-1, and residence time under 90 s. At high screw speed, localized shear heating may raise the melt above the set point and push the dye into its sublimation region. Plate-out on die lips is observed at melt temperatures above 240 °C; reducing the metering-zone barrel temperature is more effective than increasing screw speed. The dye is not a filler, so it has minimal effect on melt viscosity at normal loadings. At 0.5 wt% in general-purpose polystyrene, melt-flow rate measured by ISO 1133-1:2022 at 200 °C/5 kg may remain within ±5% of the unpigmented resin. Larger deviations generally indicate additive interactions, moisture, or degradation rather than plasticization by the dye.
When Solvent Red 8 is converted into a single-pigment masterbatch at 20–30% dye loading, the carrier resin must be selected for solubility match. Polystyrene carriers are used for PS and ABS; EVA carriers may be used for lower-temperature polyolefin applications, but the dye can migrate readily in polyolefins. The masterbatch should be vacuum-packed after cooling because hot cut pellets with internal porosity can absorb moisture and cause color strength drift. A twin-screw line with two atmospheric vents and one vacuum vent at −0.06 MPa gauge pressure provides adequate devolatilization when the melt temperature remains below 220 °C. For transparent articles, haze testing by ASTM D1003 should be added to routine production checks; an unexpected haze increase above the unpigmented base resin indicates undissolved dye or contamination. In fully dissolved transparent formulations, the dyed article should retain optical clarity even at 0.2 wt% loading, provided the resin is dry and the melt temperature is controlled.
In liquid coating systems, Solvent Red 8 is dissolved in ketones, esters, or aromatic hydrocarbons to produce transparent red solutions. A typical wood-stain preparation wets the dye with 10–15 wt% of a binder-compatible solvent before incorporation into a nitrocellulose or acrylic binder; the predispersion is then filtered through a 10 µm absolute-rated cartridge or bag filter. The dye does not require bead milling, but undissolved residues from dry powder can create specking in high-gloss lacquers. Solubility in xylene is sufficient for 15–20% dye concentrates at ambient temperature, though the exact saturation depends on the co-solvent blend. Ethanol has limited solvency, and water is a nonsolvent, so waterborne coatings require a cosolvent coupling system. Lightfastness of transparent films is measured by ISO 105-B02; the product is generally considered moderate, not high-performance. Direct sunlight exposure of thin films causes visible fading within months, and the product should not be used in exterior automotive clearcoats or architectural glazing without UV-protected overcoating. Strong oxidizing agents and reductive bleaching environments destroy the chromophore and should be excluded from the formulation.
Solvent Red 8 must not be described as a food-contact colorant. It is absent from the positive list for polymer colorants in 21 CFR 178.3297, and no FDA migration limit is established for this dye. In the European Union, plastic food-contact materials are regulated under EU Regulation 10/2011, which requires a substance-specific risk assessment for any non-listed colorant that may migrate. Because no harmonized specific migration limit exists for Solvent Red 8, use in food-contact layers should be avoided or supported by toxicological assessment conducted by the responsible manufacturer. Toy applications require heavy-metal migration testing of the finished article under EN 71-3, but the azo structure may also trigger azo-release screening depending on the scope and enforcement practice. For consumer electronics enclosures, RoHS compliance is demonstrated by X-ray fluorescence pre-screening followed by IEC 62321-5 for cadmium and IEC 62321-4 for mercury; lead and chromium require confirmatory digestion testing when screening values approach regulatory thresholds. A batch-level certificate of compliance that is not supported by these measurements should not be accepted as evidence of RoHS compliance.
Storage of Solvent Red 8 should be in closed containers at or below 35 °C and 60% relative humidity. Direct sunlight and contact with strong acids, strong bases, and reducing agents should be avoided. If moisture exposure causes agglomeration, drying at 80 °C for 2 h may restore flow, but the lot should be retested for shade and sieve residue before release. The product has a finite storage stability; suppliers commonly recommend retest intervals of 12 months for sealed original containers, but this period is not a hard shelf life and should be confirmed against long-term storage data.
