PIGMENT RED 146/ HP RED 25107

What Is PR146 / HP RED 25107

CAS 5280-68-2, CI 12485, Type: Naphthol AS Monoazo. This grade is a bluish-shade red pigment engineered specifically for solvent-based inks, offering reliable lightfastness (6 Blue Wool) and robust solvent resistance. It serves as an economical mid-performance alternative between low-cost PR57:1/PR53:1 reds and high-cost quinacridones, making it a practical choice for industrial printing applications where cost and performance balance is critical.

Why Choose HP RED 25107

This specific grade, HP RED 25107, is optimized for solvent-based inks, delivering superior dispersion and color strength in systems like nitrocellulose, polyamide, and acrylic resin formulations. Unlike its sibling HP RED 2262, which targets different application needs, HP RED 25107 provides enhanced solubility resistance and heat stability specifically tailored to solvent evaporation dynamics. Compared to HP RED 25107J, this standard variant offers a more consistent bluish shade without modifications, ensuring batch-to-batch reliability. Choose HP RED 25107 when you need a cost-effective, mid-tier red that outperforms basic monoazo reds while avoiding the premium expense of quinacridones, particularly for packaging inks and publication gravure where solvent resistance and lightfastness are non-negotiable.

Key Features

• Excellent solvent resistance prevents bleeding and migration in solvent-based ink systems, ensuring print sharpness and layer integrity.
• Good lightfastness (6 Blue Wool) enables outdoor and long-duration packaging applications without significant fading.
• Bluish shade provides a clean, bright red tone that expands color gamut in four-color process and spot-color solvent inks.
• Superior dispersibility in organic solvents reduces milling time and delivers consistent color strength across batches.
• Economic performance bridges the gap between low-cost reds and expensive quinacridones, offering a cost-efficient solution for mid-range industrial printing.

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C.I.NO.: PR146

Advantage:

Main Application Recommended: Solvent based inks

Product Description – PR146

HP RED 25107 (PIGMENT RED 146) is bluish red pigment with very good solvent resistance, primarily used in Slovent based printing inks, coatings and paints. It is somewhat yellower than PR57:1, with good perfoamnce in inks. And also very good light fastness in textile printings. is primarily applied in emulsiion and architectural paints as well, and also used in general industrial paints where durability is not important.

Recommended Application：

Coatings: solvent based paints, industrial paints
Printing inks: offset inks, solvent based 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”

Disclaimer — This Technical Data Sheet reflects our best understanding of typical product properties at the time of publication. Listed values are representative of standard production and are not intended as specifications, contractual parameters, or fitness guarantees. Batch variations within normal manufacturing tolerances may occur; users should verify critical parameters against their own requirements before use. Processing methods, formulations, and end-use environments are beyond the manufacturer’s control. The buyer assumes full responsibility for confirming product suitability through its own testing and quality assurance. No intellectual property license is granted or implied. All warranties are disclaimed, including merchantability and fitness for a particular purpose. The manufacturer is not liable for incidental, consequential, or special damages. All sales are governed by the manufacturer’s standard terms, available upon request. This product may contain particles below 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

Is PR146 specifically designed for solvent-based inks, or can it be used universally?

PR146 (HP RED 25107) is optimized for solvent-based ink systems, particularly those using esters, ketones, and aromatic hydrocarbons. Its chemical structure provides excellent solubility and stability in these aggressive solvents, unlike many pigments that require extensive grinding. For waterborne or UV systems, alternative pigments like PR170 or PR254 are more suitable due to pH sensitivity and curing compatibility. While PR146 offers vibrant red shades (CI 12485) with high transparency, it is not a drop-in replacement for other media. Always test in your specific resin-solvent blend to confirm rheology and adhesion. **Takeaway: HP RED 25107 delivers peak performance and color strength only when formulated for solvent-based inks, ensuring cost-effective dispersion and gloss.**

What are the known performance limits of PR146 regarding lightfastness and chemical resistance?

PR146 (CAS 5280-68-2) exhibits moderate lightfastness (blue wool scale 4–5 in full shade) and fair resistance to polar solvents like ethanol, but it struggles against strong acids and alkalis. In solvent-based inks, prolonged outdoor exposure may cause fading in thin films, making it suitable for indoor packaging or short-term signage rather than automotive or architectural coatings. Its heat stability is adequate up to 200°C, but above this, color change may occur. For applications requiring extreme durability, consider PR177 or PR255. **Takeaway: HP RED 25107 is a cost-effective red for interior solvent inks where moderate fastness is acceptable, but avoid harsh chemical environments.**

How does PR146 compare to its sibling grades like PR170 or PR144 in solvent-based formulations?

PR146 (HP RED 25107) is a monoazo pigment with higher transparency and brighter, more bluish-red shade compared to PR170 (which is yellower and more opaque). PR144 offers better lightfastness but lower solubility in esters, requiring more grinding energy. In solvent inks, PR146 provides excellent gloss development and flow due to its smaller particle size and narrow distribution. However, PR170 outperforms in opacity and covering power for substrates like vinyl. For economy, PR146 is often blended with PR144 to balance cost and durability. **Takeaway: HP RED 25107 excels in clean, transparent reds for solvent inks, while PR170 or PR144 are better for opacity or outdoor exposure.**

What are the key processing and dispersion challenges when using PR146 in solvent inks?

PR146 is relatively easy to disperse compared to many organic reds, but it requires careful wetting in ester or ketone solvents. Insufficient residency in bead mills can leave aggregates that reduce color strength and cause settling. Use a high-acid-value dispersant (e.g., 5–10% based on pigment weight) and maintain a viscosity below 1000 cP during milling to achieve a Hegman gauge of 6–7. Over-grinding can break particles, shifting shade towards yellow. For best results, pre-wet the pigment in the solvent for 30 minutes before milling. **Takeaway: HP RED 25107 disperses efficiently with standard equipment when using acidic dispersants. Monitor grind time to preserve its vibrant, bluish shade.**

How should PR146 be stored, and what are its substitution risks if supply is interrupted?

Store PR146 (HP RED 25107) in sealed containers away from heat, direct sunlight, and moisture. Shelf life is 3–5 years in cool, dry conditions (below 30°C). If substituting, PR144 (CI 12465) offers similar hue but lower transparency and 20% higher tinting strength, requiring reformulation. PR170 (CI 12475) shifts yellower and reduces gloss. Avoid PR254 (pyrrole) as it over-delivers in fastness but costs 3x more. Always run a complete ink trial: test viscosity, shade match, and adhesion before substitution. **Takeaway: HP RED 25107 is a reliable, cost-optimized red for solvent inks. Substitutions require full reformulation to maintain color and performance targets.**

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