Section
| HS Code | 935485 |
| Productname | Lithol Scarlet LR |
| Colorindexname | C.I. Pigment Red 49:1 |
| Colorindexnumber | C.I. 15630:1 |
| Chemicalclass | Monoazo lake pigment |
| Salttype | Barium salt |
| Color | Scarlet red |
| Physicalform | Powder |
| Primaryuse | Inks, paints, coatings, and plastics |
| Lightfastness | Moderate |
| Heatstability | Moderate |
| Acidresistance | Poor to moderate |
| Alkaliresistance | Poor to moderate |
| Solventresistance | Moderate |
| Waterresistance | Low to moderate |
| Oilabsorption | Approximately 40-50 g/100 g |
| Specificgravity | Approximately 1.8-2.0 |
| Ph | Approximately 6-8 |
| Tintingstrength | High |
| Opacity | Semi-opaque to opaque |
| Dispersibility | Good |
| Particlesize | Fine |
As an accredited Lithol Scarlet LR factory, we enforce strict quality protocols—every batch undergoes rigorous testing to ensure consistent efficacy and safety standards.
| Packing | Lithol Scarlet LR is supplied in 25 kg multi-ply paper bags with polyethylene liners, palletized for transport. |
| Container Loading (20′ FCL) | Lithol Scarlet LR is packed in sealed drums and palletized for loading into a 20′ FCL container, secured for safe transport. |
| Shipping | Lithol Scarlet LR is not classified as dangerous goods for transport. It has no UN number, hazard class, or packing group. Ship in closed, labeled containers, protected from moisture, heat, and dust, and comply with applicable local transport regulations. |
| Storage | Store Lithol Scarlet LR in a cool, dry, well-ventilated area away from direct sunlight, heat, ignition sources, and strong oxidizers. Keep containers tightly closed in the original labeled packaging to prevent moisture ingress and dust generation. Avoid dust dispersion; use local exhaust and PPE as needed. Segregate from incompatible materials and follow local regulations and the SDS. |
| Shelf Life | Lithol Scarlet LR typically has a shelf life of 5–10 years when stored cool, dry, and in its original sealed container. |
In sheetfed offset and letterpress paste ink manufacturing, Lithol Scarlet LR (C.I. Pigment Red 49:1 barium lake) is employed where a high-colour-strength scarlet red is required at moderate processing temperature and where exterior lightfastness is not the controlling specification. Production millbases are formulated with 15–25 wt% pigment on total millbase weight, dispersed in rosin-modified phenolic or alkyd resin varnish. On three-roll mills, the pigment–varnish pre-mix is passed at feed roll temperature 25–32 °C, centre roll temperature 30–38 °C, and apron roll temperature 35–42 °C; hydraulic roll contact pressures are held between 0.4 MPa and 0.8 MPa. Grind fineness is released only after a Hegman gauge reading of 5–7 is obtained. Finished inks are used in sheetfed offset carton inks, letterpress inks for coated paper, and general-purpose package printing inks. ISO 2846-1 applies where the ink is supplied as a process red reference or where colour conformity is tested against a certified reference print. REACH registration for the pigment and final product, and where printed matter can enter the toy article stream, EN 71-3 soluble barium migration from the dried print film, are the principal compliance dependencies. Because the barium lake is sensitive to alkali and soap, wet-rub and alkali drop tests on printed board are performed before specifying it for detergent carton work.
Production-scale batch records show that oil absorption influences tack development; if millbase moisture content exceeds 0.8 wt%, triple-roll milling produces variable tack at 32 °C and can shift final tack from 8 to 12 Inkometer units at 400 rpm. To control this, pigment is pre-dried at 60–70 °C when ambient relative humidity rises above 60%. Lithol Scarlet LR is not recommended for UV-curable offset inks based on cationic photoinitiator systems; published data for this specific configuration is limited. Substrates printed with this pigment include coated folding box board, cast-coated paper, and uncoated offset stock. The pigment is not selected for lamination films that undergo retort or pasteurisation because colour bleed occurs in the presence of steam and fatty acids.
Calendered flexible PVC compounds accept Lithol Scarlet LR at 0.5–2.0 phr, typically alongside calcium stearate lubricant and a phthalate or alternative plasticizer system. The pigment is not pre-dispersed as a plasticizer paste when surface bleed is a concern; instead, it is added to the high-speed mixer at 80–100 °C and then dispersed on a two-roll mill at 150–160 °C before calendering at line speeds of 15–30 m/min. Finished opaque red film thickness is 0.15–0.40 mm. The processing ceiling is 170 °C; sustained residence above 160 °C for longer than 10 min shifts the masstone toward a bluer shade and reduces tinting strength. DIN EN 12877-1 covers thermal stability testing of colorants in plasticized PVC, and REACH registration applies. Because the pigment is a barium salt, converters exclude it from food-contact materials and from toys falling under EN 71-3 unless the final article-level soluble barium extraction result is below the applicable limit. Terminal products include calendered rainwear films, shoe sole sheeting, tarpaulin laminations, and printed floor mat topcoats.
Colour matching in PVC is performed against a standard pressed or calendered chip; instrumental ΔE CMC tolerances are set at ≤ 0.8 for same-batch production. The pigment is pre-dried at 60–70 °C when ambient relative humidity exceeds 60% to prevent moisture-induced agglomeration during dry blending. Published data for long-term weathering of Lithol Scarlet LR in exterior PVC sheet is limited; therefore exterior applications are not specified.
In sulfur-cured elastomer compounds, Lithol Scarlet LR is incorporated at 1–3 phr during the second stage of a two-pass mix. Typical masterbatch mixing uses an internal mixer with jacket temperature 50–70 °C and rotor speed 30–50 rpm; the pigment is added after carbon black or silica dispersion to avoid excessive colour dilution. The compound is then sheeted on a two-roll mill at 50–60 °C and vulcanized in a compression press at 140–160 °C for 4–10 min depending on cure system. The critical thermal boundary is 160 °C; above this, the barium lake can release colour degradation products that stain adjacent rubber layers and reduce chroma. ASTM D3182 provides mixing procedures for standard rubber compounds, and ISO 2393 specifies equipment and mixing protocols for test batches. Terminal vulcanizates include dark-shaded shoe soling sheets, industrial rubber mats, and non-contact gaskets where red colour is maintained indoors. Material manufacturers exclude Lithol Scarlet LR from peroxide-cured EPDM exposed to hot-water environments because bloom can occur at 2 phr and above. No additional accelerators are typically required solely for the pigment, but the presence of the barium lake can alter scorch time by 5–15% in thiuram-accelerated NR compounds; therefore, cure curves are re-established with a moving-die rheometer before production scale-up.
On the moving-die rheometer, the change in scorch time is monitored; if scorch time deviates more than 15% from an unpigmented control, the cure package is adjusted rather than raising pigment concentration. Injection moulding of red rubber parts is limited to mould temperatures 160–170 °C and short holding times; high shear at the gate has been observed to reduce chroma in thin-wall parts when the melt exceeds 170 °C for more than 5 min. This is an operational boundary, not a recommendation for high-temperature engineering elastomer grades.
| Application context | Relevant standard or regulation | Critical measured parameter | Verification point |
|---|---|---|---|
| Offset/letterpress paste inks | ISO 2846-1; REACH; EN 71-3 where applicable | Hegman gauge reading 5–7; soluble barium | Dried print film |
| Flexible PVC calendering | DIN EN 12877-1; REACH | Thermal stability at 170 °C; ΔE CMC | Calendered sheet |
| Sulfur-cured rubber | ASTM D3182; ISO 2393; REACH | Scorch time; cure rheology | Vulcanized slab |
| Water-based decorative paints | ASTM D4236; EU CLP (EC) No 1272/2008; EN 71-3 | Soluble barium in dried coating | Dried latex film |
| Textile pigment printing | OEKO-TEX Standard 100; ISO 105-C06; REACH | Extractable barium; wash fastness | Printed fabric |
| Artists’ oil colour | ASTM D4236; EU CLP (EC) No 1272/2008; REACH | Oil absorption; tube extrusion | Milled millbase |
Where water-based decorative paint formulations require a barium lake with a clean bluish red undertone, Lithol Scarlet LR is dispersed into a surfactant-containing aqueous slurry at 2–8 wt% of total paint weight. The pigment performs within an aqueous binder pH window of 7.5–9.0. Processing is carried out on a high-speed dissolver with a Cowles blade at tip speed 15–20 m/s for 15–20 min, followed by let-down into a vinyl acetate-ethylene or acrylic latex binder. Final products include interior matt wall paints, poster paints, craft paints, and school paints. For consumer paint products sold in the United States, ASTM D4236 labelling requires a chronic hazard evaluation; in the EU, the final paint must comply with CLP Regulation (EC) No 1272/2008 and REACH. Where the paint will be applied to children’s boards or toys, EN 71-3 soluble barium extraction is tested on the dried coating. Lithol Scarlet LR is excluded from exterior masonry paints because its lightfastness in reduced tints falls below the minimum required for facade exposure.
Batch control requires a fineness-of-grind gauge reading of 30–40 μm before let-down, with the slurry filtered through a 100 μm mesh bag to remove agglomerates. Lithol Scarlet LR is incompatible with highly alkaline silicate paints above pH 10, where barium lake can decompose. Applications are therefore confined to synthetic resin-bound interior paints rather than mineral silicate systems.
For pigment printing on cotton and cotton-polyester blends, Lithol Scarlet LR is mixed into an aqueous self-crosslinking acrylate binder at 1–5 wt% of the wet print paste. Rotary and flat-bed screen printing are both suitable; the pigment is pre-dispersed with a small quantity of anionic wetting agent before addition to the binder to prevent coagulation. The printed fabric is dried at 90–110 °C and cured in a hot-air oven at 140–150 °C for 2–3 min. Curing above 160 °C measurably reduces wash fastness and causes shade dulling; therefore, belt speed and oven temperature are interlocked. Finished articles include printed T-shirts, canvas tote bags, and indoor home textile panels. Compliance is assessed against OEKO-TEX Standard 100 where the final article carries the label, with specific attention to extractable barium; REACH applies to the imported print paste. Lithol Scarlet LR is not recommended for garments requiring ISO 105-C06 wash fastness ratings above 3–4. No formaldehyde-based crosslinker is used in the binder system when the pigment is formulated for skin-contact textiles.
Screen mesh selection is typically 43–80 threads/cm for rotary screens and 40–80 threads/cm for flat screens; print paste viscosity is adjusted to 10–20 Pa·s at 25 °C. The pigment is not suitable for discharge printing with zinc formaldehyde sulphoxylate because reductive conditions strip the azo chromophore. Published data for high-energy discharge processes is limited.
Artists’ oil colour and alkyd paint milling subjects Lithol Scarlet LR to low-temperature, high-viscosity shear rather than the high-speed dissolution used in aqueous paints. The pigment loading is 20–30 wt% of the oil-containing millbase, with linseed oil or safflower oil as the wetting vehicle; the paste is milled on a three-roll mill at roll temperatures not exceeding 45 °C to prevent crystallization of the binder. Final products include artists’ oil colour tubes, alkyd resin paints, and artists’ poster colours. For products entering the United States, ASTM D4236 requires evaluation of chronic health hazards; in Europe, CLP Regulation (EC) No 1272/2008 and REACH apply. The pigment is not suitable for lime fresco or exterior mural work because of poor alkali resistance and limited lightfastness in reductions. Oil colour manufacturers pre-test the pigment for linseed oil absorption and oil separation during tube storage; at loadings above 30 wt%, the millbase develops a short, crumbly body that does not produce acceptable tube extrusion.
Tinting strength in artists’ colour is standardized by mixing 1 part pigment with 9 parts titanium dioxide in linseed oil and comparing against a house reference. Lithol Scarlet LR often requires a wetting agent at 0.2–0.5 wt% of pigment to reduce mill time, particularly when the oil acid number is below 1 mg KOH/g. Without this additive, three-roll mill passes may increase from 3 to 6 to reach a Hegman reading of 4–5.
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Lithol Scarlet LR is marketed as a barium lake of a sulphonated monoazo chromophore corresponding to C.I. Pigment Red 49:1, Colour Index 15630:1, CAS 1103-38-2. The LR suffix is a manufacturer-specific grade model identifier; it denotes a surface-treated, low-dusting delivery form rather than a separate Colour Index entity. The product is supplied as a red free-flowing powder or granular material. Typical physical constants fall within the ranges 1.4–1.6 g/cm³ for density determined by ISO 787-10, 35–55 g/100 g for oil absorption determined by ISO 787-5, and 6.0–8.0 for aqueous suspension pH measured by DIN ISO 787-9. Because the pigment is a classical azo lake rather than a high-performance organic pigment, its technical relevance is concentrated in printing inks, rubber, plasticized PVC, and polyolefin systems processed below the thermal degradation threshold. Published data for the specific LR surface configuration is limited; therefore the parameters presented here are drawn from the generic C.I. Pigment Red 49:1 class and should be verified against the batch certificate.
Chemical composition of the barium lake reduces aqueous solubility and stabilizes the chromophore in hydrophobic binders, but it also imposes sensitivity to strong acids and bases. The barium counterion contributes to the pigment’s higher density relative to resin-bonded organic pigments and influences its rheology in high-solids offset ink formulations. These characteristics place Lithol Scarlet LR in the lower-cost, moderate-performance segment of red organic pigments, suitable where maximum heat and light fastness are not required.
The structural difference lies in the precipitation of a soluble monoazo dye acid with a barium salt, producing an insoluble salt lattice. This laking step shifts the visible absorption maximum into the red region and lowers solubility in printing ink vehicles, while leaving the chromophore susceptible to strong reducing conditions in closed ink systems. In aqueous dispersion, the pigment surface carries sulphonate residues that require non-ionic or anionic wetting agents for effective milling; cationic wetting agents can induce flocculation. The laked structure also increases polarity relative to phthalocyanine pigments, which changes the adsorption behaviour of alkyd resins and mineral oil-based vehicles on the pigment surface. The barium lake structure further produces a marked increase in alkalinity sensitivity compared with non-laked disazo red pigments, because the metal bridge can be hydrolyzed under elevated pH.
Dispersion of Lithol Scarlet LR in a mineral oil-based sheetfed offset vehicle on a triple-roll mill with nip pressures between 1.0 and 2.5 MPa typically reduces grindometer readings below 15 µm after three passes. For water-based flexographic inks, predispersion in a high-speed dissolver at 20 m/s tip speed followed by a horizontal bead mill charged with 0.6–0.8 mm yttria-stabilized zirconia media is required to break agglomerates. The oil absorption value controls pigment loading in paste inks; formulations exceeding the critical pigment volume concentration exhibit a rapid viscosity rise and loss of transfer sharpness. In plastics, masterbatch production on a co-rotating twin-screw extruder with L/D ratio 44:1 and screw speed 250 rpm provides adequate distributive mixing when the pigment is pre-blended with low-density polyethylene at 2:1 pigment-to-polymer ratio and fed downstream of the melt seal. These operational limits prevent over-shearing, which can fracture primary particles and generate fines that increase filtration pressure in film extrusion.
Thermal stress is the primary processing boundary for Lithol Scarlet LR in polyethylene and polypropylene. Barium lake monoazo pigments undergo progressive ring oxidation and metal-lake disruption above the 170–180 °C range under shear; observable effects include shade shift toward magenta, loss of colour strength, and evolution of acidic decomposition residues measured by pH drop in condensed volatiles. In injection moulding of polypropylene, melt temperatures above 200 °C with residence time exceeding 5 min frequently produce unacceptable darkening; therefore the pigment is not suitable for engineering resins processed above 220 °C. The degradation pathway is accelerated by residual peroxide from controlled-rheology polypropylene and by primary antioxidants of the hindered phenol class, while secondary phosphite antioxidants provide only partial protection. Processors are cautioned not to combine this pigment with amine-based processing aids at high temperatures because the amine can coordinate with the barium centre and destabilize the lake. Validation should be performed by measuring colour difference ΔE*ab per ISO 11664-4 after five consecutive heat histories.
In nitrocellulose-based flexographic inks, the pigment exhibits adequate solvent fastness in ethyl acetate, isopropanol, and ethanol mixtures; however, migration into polypropylene packaging film can occur at elevated temperatures. For paper packaging, migration is less critical than for fatty food simulants. Alkali resistance is lower than C.I. Pigment Red 57:1; contact with soap or alkaline aqueous media produces a yellow-brown shift. These characteristics differentiate Lithol Scarlet LR from blue-shade calcium lake pigments and from more robust disazo condensation reds. Specifications for solvent bleed are evaluated by extraction for 24 h at 50 °C in ethanol and ethyl acetate, with optical density of extract measured at 520 nm.
In plasticized PVC, Lithol Scarlet LR is classified as a migrating organic pigment. Static contact against white PVC at 60 °C under 5 kPa pressure for 72 h results in visible staining, which excludes the pigment from toys and food-contact articles tested under EN 71-10 and EN 71-11. The mechanism involves dissolution of the barium lake in the plasticizer phase, migration of the chromophore along the plasticizer concentration gradient, and re-precipitation at the contact interface. Dioctyl phthalate and diisononyl phthalate plasticizers show stronger extraction than polymeric plasticizers; migration is reduced but not eliminated in plasticized PVC compounds using a 1:1 replacement of monomeric plasticizer with linear polyester plasticizer. For cables and footwear compounds where the contact layer is dark or where staining is acceptable, this property does not constrain use. However, formulation transfer to food-contact vinyl gloves or medical devices is not permitted without explicit positive-list verification.
Accelerated weathering in a Xenon arc instrument with daylight filters and irradiance 60 W/m² at 300–400 nm positions the lightfastness of Lithol Scarlet LR in the low to moderate class. Mass-tone blue wool ratings generally fall between 3 and 4 per ISO 105-B02; reduction with titanium dioxide to 1:10 lowers the rating to 2–3. Outdoor applications in polypropylene, PVC window profiles, or automotive exterior coatings are outside the operational boundary. The photodegradation mechanism for barium monoazo lakes involves photoinduced cleavage of the azo linkage, followed by formation of colourless naphthol and amine fragments; this is accelerated in humid conditions because the barium lake absorbs moisture and promotes hydrolytic attack at the metallized sulphonate site. For light-stable replacements, formulators select C.I. Pigment Red 57:1 for alkaline-sensitive films or C.I. Pigment Red 122 for durable outdoor polyolefin coloration.
| Property | Lithol Scarlet LR / C.I. PR49:1 | C.I. PR57:1 | C.I. PR53:1 |
|---|---|---|---|
| Colour Index number | 15630:1 | 15850:1 | 15585:1 |
| Lake metal | barium | calcium | barium |
| Mass tone hue | yellowish red | blue-red | yellow-red |
| Density, ISO 787-10 | 1.4–1.6 g/cm³ | 1.5–1.7 g/cm³ | 1.4–1.6 g/cm³ |
| Oil absorption, ISO 787-5 | 35–55 g/100 g | 40–60 g/100 g | 35–50 g/100 g |
| Lightfastness mass tone, ISO 105-B02 | 3–4 | 4–5 | 3–4 |
| Heat stability in polyolefin | 170–180 °C | 200–220 °C | 150–170 °C |
Regulatory screening for C.I. Pigment Red 49:1 requires separate verification for each target jurisdiction. REACH Regulation (EC) No 1907/2006 registration status for the substance identity under CAS 1103-38-2 must be confirmed through the supplier’s registration dossier. Under the EU Plastics Regulation (EU) No 10/2011, the pigment is not universally positive-listed; any food-contact polymer application requires a specific migration limit assessment for the final article. US FDA clearance must be verified under the applicable section of 21 CFR for polymer colorants; C.I. Pigment Red 49:1 is not a listed food dye under 21 CFR 74. The RoHS Directive 2011/65/EU does not restrict the pigment identity, but heavy metal impurities must remain below 100 mg/kg for cadmium, lead, mercury, and hexavalent chromium. The barium content of the lake must be reported in the safety data sheet and can trigger soluble barium limits in toy safety standards.
| Regulation | Status |
|---|---|
| REACH Regulation (EC) No 1907/2006 | Confirm registration under CAS 1103-38-2 |
| EU Plastics Regulation (EU) No 10/2011 | Not universally positive-listed; verify specific migration limit for final article |
| US FDA 21 CFR | Verify polymer colorant clearance; not listed as a food dye under 21 CFR 74 |
| RoHS Directive 2011/65/EU | No identity restriction; heavy metal impurities below 100 mg/kg |
| EN 71-10 and EN 71-11 | Migrating colorant; not suitable for extractable colorant limits |
Compared with C.I. Pigment Red 48:2, which is a calcium lake of a β-oxynaphthoic acid monoazo chromophore, Lithol Scarlet LR shows a yellower hue, lower heat stability in polyolefins, and a different response to alkaline printing ink fountain solutions. Compared with C.I. Pigment Red 57:1, the LR grade is significantly more alkali-sensitive and migrates more readily in plasticized PVC; however, it can be dispersed in aromatic-free offset vehicles at higher pigment loadings without the thixotropy build sometimes caused by platelet-like rubine pigment crystals. Compared with C.I. Pigment Red 53:1, Lithol Scarlet LR is bluer and has a slightly higher processing ceiling, but both barium lake pigments share low lightfastness and a common exclusion from durable outdoor and food-contact applications.
Storage of Lithol Scarlet LR requires sealed containers at 25 °C and relative humidity below 60% to prevent moisture uptake above 2%; re-drying at 70 °C for 4 h is required if the powder has been exposed to humidity above 60%. The pigment is incompatible with concentrated oxidizing acids, which strip the barium ion and produce soluble dye acid; it is also incompatible with strong reducing agents used in some in-can preservative systems. Dust explosion parameters follow standard organic pigment handling: minimum ignition energy below 10 mJ and minimum explosible concentration 30 g/m³, requiring conductive flooring and bonding for transfer lines. These parameters are drawn from organic pigment class data; specific LR grade testing must be confirmed by the supplier safety data sheet.
