PIGMENT RED 57:1/ HP RED 2540
Pigments For Offset Inks · Pigments for Printing Inks · Pigments for Solvent Based Inks
Technical Information
What Is Pigment Red 57:1 / HP RED 2540
Pigment Red 57:1 (CAS 5281-04-9, CI 15850:1) is a monoazo lake pigment, the highest-volume organic red globally. Known as 4B toner, its bluish-red shade matches the standard magenta position in the CIE 12-66 European Color Scale for four-color process printing. The pigment exists as a keto-hydrazone tautomer with 1.5 moles of water of crystallization, synthesized under controlled pH below 7.0 to achieve the bluer crystal form. HP RED 2540 is the bluish-red grade optimized for solvent-based gravure packaging inks where a cool, clean process magenta is required.
Why Choose HP RED 2540
HP RED 2540 delivers the bluish-red shade that serves as standard process magenta in CMYK gravure printing. Its cool undertone makes it the preferred choice when clean violet and blue overprints are critical in multi-color flexible packaging work. Unlike the yellowish-red HP RED 2539 which excels in warm food packaging palettes, HP RED 2540 is the go-to grade for designs dominated by cool tones. The calcium lake structure is stabilized for reliable dispersion in NC, PVB, and polyamide solvent systems at an economical price point for high-volume production. Choose 2540 when your print job demands a cool, bluish process red — choose 2539 when warm, golden reds are needed.
Key Features
- Bluish-red masstone with clean cool undertone — the standard process magenta shade for solvent-based gravure CMYK printing
- Complementary to HP RED 2539 (yellowish-red): select by design palette — 2540 for cool reds and violets, 2539 for warm reds and oranges
- Crystal morphology stabilized for consistent shade in toluene, ester, and ketone solvent systems without yellow drift
- High tinctorial strength allows lower pigment loading while maintaining color intensity in thin gravure ink films
- Good transparency for multi-layer printing on flexible substrates with reliable batch-to-batch color control
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Technical Data:
| Product Information | ||||
| Chemical Type | monoazo | CAS NO. | 5281-4-9 | |
| C. I. Name | Pigment Red 57:1 | EINECS / ELINCS NO. | 226-109-5 | |
| C. I. Constitution No. | 15850:1 | Chemical Formula | C18H12N2O6SCa | |
| Technical Performance | ||||
| Full Shade | Tint | |||
| Weather Resistance | 4-5 | 3 | Heat Stability °C | 240°C |
| Light Fastness | 8 | 7 | ||
| Physical Properties | ||||
| Physical Form | Powder | Resistance to Acid | 4 | |
| Specific Density (g/cm3): | 1.60 ± 0.1 | Resistance to Alkali | 4 | |
| Specific Surface(㎡/g): | 50 | Migration resistance PVC | 5 | |
| Oil Absorption | 45 ± 10 | Low warping applications | Not suitable | |
| pH Value | 6.5 -8.5 | |||
| Volatile Matter | 1% max | |||
| Packaging | ||||
| 25kgs/bag 350kgs/Pallet | ||||
| Storage | Shelf Life | 5 years | ||
| Should be stored in cool, dry and ventilate place. | ||||
| TRANSPORTATION | ||||
| Avoid inversion, sunlight, moisture and crash. Avoid damage the package. | ||||
- 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 Pigment Red 57:1
How does HP RED 2540 compare with HP RED 2539, and how do I choose between them?
HP RED 2540 and HP RED 2539 are complementary PR57:1 grades differentiated by shade direction. HP RED 2540 is the bluish-red grade providing the cool, clean red that functions as standard process magenta in CMYK gravure printing. HP RED 2539 is the yellowish-red grade providing warm, golden-toned red preferred for food packaging and warm color palettes. The choice is straightforward: if your design is cool-toned with blues, violets, and clean reds, choose 2540. If warm-toned with oranges, yellows, and golden reds, choose 2539. For offset inks requiring low viscosity, use HP RED 2738. For plastics applications, use HP RED 23145.
What is Pigment Red 57:1 used for in the printing ink industry?
Pigment Red 57:1 (CAS 5281-04-9, CI 15850:1) is the most widely consumed organic red in the global printing ink industry because its bluish-red shade naturally aligns with the standard magenta position in four-color process printing. HP RED 2540 is specifically optimized for solvent-based gravure packaging inks — snack food wrappers, confectionery bags, and laminated pouches — where its cool magenta tone provides excellent press performance in NC-based and PVB-based solvent systems. Ink formulators value its reliable wetting behavior, consistent color reproducibility across long print runs, and high tinctorial strength that keeps ink costs competitive in high-volume flexible packaging production.
What is the heat stability and light fastness of HP RED 2540?
As a PR57:1 monoazo lake pigment, HP RED 2540 is heat stable to 180°C for 10 minutes, which is adequate for solvent-based ink drying and standard curing cycles in packaging printing. Light fastness is rated 4-5 on the Blue Wool scale at full shade, dropping to 3-4 in reductions — typical for the monoazo lake class. The 1.5 moles of water of crystallization in the pigment crystal structure can reversibly release above 100°C, causing a temporary shade shift that returns upon cooling. For applications requiring higher heat resistance or light fastness, consider high-performance alternatives such as PR122 (quinacridone) or PR254 (DPP red).
Can HP RED 2540 be used in water-based ink systems?
HP RED 2540 is designed for solvent-based gravure inks and performs best in toluene, ester, and ketone systems. It can be formulated into water-based inks with appropriate wetting and dispersing agents, but formulators should be aware that PR57:1 is a calcium lake pigment that can exhibit sensitivity to alkaline water-based environments. Calcium-to-sodium ion exchange in alkaline systems may cause viscosity increases over time. For dedicated water-based flexo or gravure applications, careful pH control below 8.0 and proper pigment pre-dispersion are essential to maintain color strength and avoid viscosity drift.
What packaging and shelf life does HP RED 2540 come with?
HP RED 2540 is supplied in 25 kg paper bags as standard, with 400 kg per pallet. Custom packaging options include 500 kg bulk bags for larger orders. The recommended shelf life is 3 to 5 years when stored in the original sealed packaging under cool, dry conditions away from direct sunlight and moisture, below 30°C and 60% relative humidity. Each production lot is tested for color strength, shade consistency, and dispersibility before release. Certificates of Analysis and Technical Data Sheets are available for every batch upon request.