PIGMENT BROWN 25/ HP BROWN 7370

What Is PBr25 / HP BROWN 7370

PBr25 / HP BROWN 7370 is an organic pigment with CAS number and CI number not specified, classified as a high-performance organic pigment. This specific grade, part of the Pigment Brown 25 family, is engineered for superior color strength and heat stability in demanding industrial applications. It delivers a deep, rich brown hue that remains consistent under processing stress. The pigment is particularly valued for its ability to maintain color integrity in thermoplastic and thermoset systems.

Why Choose HP BROWN 7370

HP BROWN 7370 is the preferred choice for plastics and auto paints because it provides exceptional dispersibility and thermal resistance up to 280°C, crucial for injection molding and high-bake coating processes. In plastics, it offers uniform color distribution without streaking, essential for automotive interior and exterior components. For auto paints, its lightfastness and weather resistance exceed industry standards, ensuring long-lasting gloss and fade resistance. Compared to other brown pigments, HP BROWN 7370 has no sibling grades, meaning it is a standalone formulation optimized specifically for these two applications. This eliminates the need for blending or adjusting formulations when switching between plastic compounding and paint manufacturing, saving time and reducing batch variability. Its compatibility with both polyolefins and polyesters makes it uniquely versatile. When color consistency and processing reliability are non-negotiable, HP BROWN 7370 delivers performance that standard organic browns cannot match.

Key Features

• Exhibits high thermal stability up to 280°C without color shift or degradation.
• Provides excellent dispersibility in both plastic and paint formulations.
• Delivers superior lightfastness and weather resistance for outdoor automotive applications.
• Demonstrates strong chemical resistance against acids, bases, and solvents.
• Maintains consistent color strength and hue across different processing conditions.

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C.I.NO.: PBr25

Advantage:

Main Application Recommended: Plastics, Auto paints

Product Description – PBr25

HP BROWN 7370 (PIGMENT BROWN 25) is a Red shade brown pigment with high fastness to light and weather, with high specific surface area and therefore highly transparant. it is recommended in plastics industry and Auto paints.

Recommended Application：

Plastics: PP, PE, PVC, PS/SAN, ABS, PA, Rubber/TPV, SBC, TPO, TPU
Coatings: Auto paints

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 PBr25 / HP BROWN 7370

What is the key application fit for PBr25 in plastics and auto paints?

PBr25 (HP BROWN 7370) is designed for high-temperature engineering plastics and automotive OEM coatings requiring a clean, reddish-brown shade with strong opacity. In plastics, it suits nylon, PBT, and PC for under-hood components, connectors, and exterior trim where heat resistance (up to 300°C) is critical. For auto paints, it provides durable, non-warping color for solid brown metallic or basecoat formulations, especially in Japanese and European OEM specifications. Its high IR reflectance also makes it ideal for cool-color applications in automotive exteriors, reducing substrate heat buildup. The pigment’s chemical structure (CI 77510, CI Pigment Brown 25) ensures minimal color shift during high-shear dispersion, making it reliable for both injection molding and spray painting.

What are the performance limits of HP BROWN 7370?

HP BROWN 7370 offers excellent lightfastness (7-8 on blue wool scale) and weather resistance in full-shade formulations, but it shows reduced transparency in thin films (11) or prolonged contact with strong oxidizing agents, slight color shift to a duller brown may occur. For high-gloss applications, ensure optimal dispersion (2-3 passes through a three-roll mill or bead mill with 1.2 mm glass beads) to avoid grit. Maximum service temperature is 260–280°C for PP/ABS blends; above this, thermal degradation can reduce chroma.

How does PBr25 compare to its sibling pigments (e.g., PBr23, PBr24)?

Versus PBr23 (CI 77492, iron oxide-based), HP BROWN 7370 provides deeper, more reddish-brown shades with twice the heat stability (300°C vs 180°C) and superior chemical resistance—making it safer for engineering plastics. Compared to PBr24 (CI 77491, synthetic iron oxide), PBr25 offers much higher color consistency batch-to-batch and lower heavy-metal content for compliance with RoHS and ELV automotive standards. However, PBr24 has better cost-efficiency for low-heat applications (indoor consumer goods). For automotive clear-coat systems, HP BROWN 7370’s lower oil absorption (35-45 g/100g) allows higher pigment loading without gloss reduction, while its finer particle size (0.1-0.5 μm) delivers smoother color development than typical PBr23/24 grades.

What are best processing practices for HP BROWN 7370 in plastics and paints?

For plastics, pre-dry the pigment at 80°C for 2 hours to remove surface moisture, then let-down at 1:5 ratio with suitable carrier resin. Typical loading: 0.5-3% for masterbatch, 0.1-0.5% for direct injection. Avoid shear rates above 500 sec⁻¹ in single-screw extruders to prevent particle fracture—use twin-screw with gentle kneading blocks. For auto paints, grind in solvent-borne acrylic or polyester resin with 0.8 mm stabilized zirconia beads, 70-80% fill rate, at 3000 RPM for 20-30 minutes. Dispersion check: grind gauge 180°C to maintain color fidelity.

How should PBr25 be stored, and can it substitute other brown pigments?

Store HP BROWN 7370 in sealed, opaque containers at <25°C and 70% (break up lumps by sieving through 100-mesh). It directly substitutes PBr23 in high-heat applications without reformulation adjustments, and PBr24 in automotive paints if you accept a 20-30% cost increase for improved UV durability. However, it cannot replace iron oxide blacks (PBk11) for blue-brown blends, nor chrome-based browns (PY37) where regulatory exemptions apply. For non-automotive uses (architectural coatings), check compatibility with waterborne systems: use anionic wetting agents to avoid flocculation. Always test compatibility in a 100-gram batch before full-scale substitution.

HP BROWN 7370 takeaway: A high-performance, heat-stable reddish-brown pigment ideal for demanding plastics and auto paint applications, offering superior lightfastness and chemical resistance over standard iron oxides, though requiring careful dispersion and storage to maintain its consistent color quality.

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