PIGMENT RED 57:1/ HP RED 23145

Technical Information

What Is Pigment Red 57:1

Pigment Red 57:1 (CAS: 5281-04-9, CI Number: 15850:1) is a monoazo lake pigment, specifically the calcium salt of a beta-oxynaphthoic acid derivative, and holds the title of the highest-volume organic red pigment used globally. Its molecular structure (C18H12N2O6SCa) exists as a keto-hydrazone tautomer, and the key to its performance lies in a carefully controlled crystallization process which locks in 1.5 moles of water. This stable crystal form gives the pigment its inherently bluish-red (magenta) shade, making it the standard for 4-color process printing and a cornerstone of the entire printing ink industry. Beyond ink, this chemistry’s high tinctorial strength and solvent resistance make it a versatile workhorse for many color-critical applications.

Why Choose HP RED 23145

While standard grades of Pigment Red 57:1 dominate the printing ink market, HP RED 23145 is specifically engineered for the demanding world of plastics. Unlike ink grades optimized for transparency or flow, this grade is designed to achieve exceptional dispersion in high-viscosity polymer melts like PP, PE, PVC, and rubber/TPV compounds. Its surface treatment and particle size distribution are tailored to prevent agglomeration during compounding, which is critical for achieving consistent color without specks or streaks. HP RED 23145 prioritizes high heat stability (up to 180°C) and migration resistance so the color stays put and doesn’t bleed in soft PVC or rubber. This makes it a direct alternative to high-performance products like Clariant PV Fast Red or BASF Sicopal Red, offering the high-strength PR57:1 chemistry in a robust, plastics-ready format.

Key Features

• Engineered for superior dispersion in polyolefins (PP, PE) and PVC, eliminating color specks and ensuring uniform shade strength in the final article
• Offers excellent migration resistance, meaning the pigment will not bleed or stain adjacent materials in soft PVC or rubber compounds during storage or use
• Maintains consistent color performance under processing conditions up to 180°C, preventing thermal degradation or shade shifts during injection molding or extrusion
• Provides high color strength, requiring a lower pigment loading to achieve a target shade, which helps maintain the physical properties of the plastic matrix
• Delivers a clean, bluish-red (magenta) shade with high chroma, making it ideal for creating vibrant reds, pinks, and for use as a process color component in plastic masterbatches

Recommended Applications

Primary: Masterbatch and compounding for general-purpose polyolefins (PP, PE), rigid and plasticized PVC, and rubber/TPV molding.

Secondary: HIPS and ABS where a high-strength, migration-stable magenta is required.

Shade Selection Guide: For a yellower, more scarlet red, consider a different Pigment Red 57:1 grade with a larger particle size distribution. For solvent-based gravure packaging inks, use HP RED 2540. For food packaging warm reds, use HP RED 2539. For low-viscosity offset, use HP RED 2738.

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.