PIGMENT RED 146/ HP RED 25107J

What Is PR146 / HP RED 25107J

CAS 5280-68-2, CI 12485, Naphthol AS Monoazo red with a bluish shade. This specific grade, HP RED 25107J, is engineered for inkjet inks, offering an economical mid-performance solution that bridges the gap between low-cost monoazo reds and high-cost quinacridones. It delivers good lightfastness (Blue Wool 6) and solvent resistance, making it suitable for demanding inkjet applications where color stability and durability are required. Its bluish undertone provides a distinct red shade for vibrant printing output.

Why Choose HP RED 25107J

Choose HP RED 25107J when you need a reliable, cost-effective red for inkjet inks that outperforms basic monoazo reds without the premium cost of quinacridones. Unlike its sibling HP RED 2262, which may target different viscosity or particle size profiles, or HP RED 25107 (the base grade), the “J” variant is specifically optimized for inkjet ink formulations. It offers superior dispersion stability in aqueous systems, crucial for nozzle jetting reliability. This grade excels in applications where color consistency, lightfastness, and solvent resistance are needed but budget constraints prevent using high-performance pigments. Use it for industrial inkjet printing, where a bluish red shade with good weatherability is required, and where you need a clean, bright color without the cost penalty of premium options.

Key Features

• Good lightfastness (Blue Wool 6) ensures printed inkjet images resist fading over time in indoor and some outdoor conditions.
• Superior solvent resistance protects against bleeding and color shift when inkjet prints contact common solvents or chemicals.
• Optimized particle size distribution for inkjet fluids, improving nozzle jetting stability and reducing clogging risks in printheads.
• Bluish red shade delivers a clean, vibrant color space that expands the gamut for high-quality inkjet reproduction.
• Excellent dispersion stability in water-based inkjet formulations prevents agglomeration, maintaining consistent color and print performance batch-to-batch.

C.I.NO.: PR146

Advantage:

Main Application Recommended: inkjet inks

Product description – PR146

HP RED 25107J (Pigment red 146) is a bluish red pigment with very good solvent resistance, even compared to other group II Naphthol AS pigments. It is primarily used in eco inkjet inks.

Recommended Application：

Printing inks: offset inks, solvent based inks, water based inks, inkjet inks

Technical Data:

• Light fastness: Light fastness rating is assessed on 1 to 8 Blue Wool scale where 1 = ‘Poor’ and 8 = ‘Excellent’.
• Heat Stability: Heat stability values given indicate the maximum temperature at which the pigment can be stoved for 10 min. on the full shade and in reductions without undergoing any significant change in shade.
• Oil absorption: The oil absorption is determined on the basis of EN ISO 787-5 and given in g linseed oil per 100 gm. pigment.
• Solvent bleeding: The bleeding in solvents is tested using the powder grades and the visual rating given on 1 to 5 Grey scale
  where 1 = ‘Heavy bleeding’ and 5 = ‘No bleeding”

Technical Note — The data and recommendations provided are based on HONOR Pigment’s internal testing and manufacturing experience. They are offered in good faith to assist customers in evaluating product suitability for their specific applications. As processing conditions, formulations, and end-use requirements vary widely, customers should conduct their own validation under actual use conditions. HONOR Pigment makes no warranties, express or implied, regarding the accuracy of this information or its fitness for any particular purpose. Nothing herein shall be construed as a license or recommendation to infringe any patent. HONOR Pigment’s standard terms and conditions of sale apply.oduct contains particles < 0.1 μm. Any user of this product is responsible for determining the suitability of Honor Pigments’s products for its particular application & to ensure that any proprietary rights & existing laws & legislation are observed.

Frequently Asked Questions About PR146

What specific inkjet formulations is HP RED 25107J designed for?

HP RED 25107J (PR146) is engineered specifically for aqueous inkjet inks, with a primary focus on dye-based or pigment-dispersion systems requiring high-purity red. It targets formulation parameters typical of thermal and piezo printheads, offering a clean magenta hue without the blue undertones of Quinacridone pigments. Its particle size distribution (typically D50 below 200 nm) ensures reliable jetting without nozzle clogging. It performs best in neutral to slightly alkaline pH (7.5–9.0) and is optimized for use with polymeric dispersants like styrene-acrylic resins. Avoid solvent-based systems as its chemical structure (CAS 5280-68-2) is unstable in non-aqueous carriers. HP RED 25107J delivers saturated reds with minimal flocculation in water-based inkjet vehicles.

What are the key performance limits of HP RED 25107J regarding lightfastness or heat?

Unlike high-durability inorganic pigments, PR146 (CI 12485) exhibits moderate lightfastness (typically 3–4 on the Blue Wool scale) and limited thermal stability above 120°C. Prolonged UV exposure may cause fading in uncoated media, making it unsuitable for outdoor signage unless overcoated with UV-absorbing laminates. Heat degradation becomes apparent during accelerated aging at 80°C/85% RH, where the chroma drops by 15–20% over 72 hours. It is not recommended for high-speed thermal inkjet systems that exceed 40°C printhead temperatures. For archival or heat-intensive applications, blend with high-stability magenta pigments. HP RED 25107J excels in indoor photo and office printing where balanced cost and color vibrancy are critical.

How does HP RED 25107J compare to its sibling grade PR57:1 (Lithol Rubine)?

PR146 (HP RED 25107J) is a naphthol-based red, while PR57:1 is a calcium lake of azo dye. The key difference is hue: PR146 yields a yellowish-red (CIELAB L* 45–50, a* 55–60, b* 30–35) ideal for warm reds, whereas PR57:1 is bluer and less transparent. PR146 has better thermal stability (up to 10°C higher before decomposition) and lower tendency to bleed in aqueous environments due to its larger crystal structure. However, PR57:1 offers higher tinctorial strength at similar loading. In inkjet, PR146 demonstrates superior dispersion stability without the calcium-induced settling seen in PR57:1 slurries. Choose PR146 when you need cleaner, warmer reds with longer shelf life in waterborne systems. HP RED 25107J provides the best balance for vivid red inkjet formulations over PR57:1.

What is the recommended dispersion process for HP RED 25107J to avoid particle agglomeration?

Use a two-stage bead milling process with 0.3–0.5 mm yttria-stabilized zirconia beads in a vertical mill. Pre-wet the powder with deionized water and a polyacrylic dispersant (1:1 ratio by weight) for 10 minutes at 500 rpm. Primary milling at 2,500 rpm for 30 minutes reduces agglomerates to D90 under 500 nm. Follow with secondary milling at 1,500 rpm for 20 minutes to achieve D50 120–160 nm. Maintain the slurry temperature below 35°C using a chiller. Avoid high-shear rotor-stator mixers alone as they can create air bubbles. Add a biocide (e.g., 0.1% MIT) to prevent microbial growth during storage. Filter through a 1 μm absolute cartridge before filling. HP RED 25107J disperses efficiently when the pH is kept at 8.2–8.5 throughout the process.

Can HP RED 25107J be substituted for other naphthol reds, and what storage conditions are required?

Direct substitution for PR188 or PR112 is not advised because PR146 has a different crystal phase (beta vs. alpha) affecting rheology and color strength. In formulations, reduce loading by 8–12% to match the chroma of PR188 due to its higher opacity. For storage, keep the dry powder in sealed, opaque HDPE containers at 15–30°C and below 50% relative humidity. Opened containers must be re-sealed with desiccant (silica gel) to prevent moisture adsorption, which causes caking and loss of dispersibility. The shelf life is 3 years if kept from direct sunlight; discoloration (darkening) indicates degradation. For liquid dispersions, store at 5–25°C and use within 6 months of milling. HP RED 25107J maintains consistent performance only when protected from humidity and temperature extremes.

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