PIGMENT YELLOW 191/ HP YELLOW 1349

What Is PY191 / HP YELLOW 1349

PY191, also known as HP YELLOW 1349, is an organic pigment with no assigned CAS or CI number. As an organic pigment type, it provides vivid, high-chroma yellow coloration. This grade is specifically engineered for plastics applications, offering excellent dispersibility and heat stability. It delivers strong tinting strength and consistent batch-to-batch performance, making it a reliable choice for industrial polymer coloring. Its chemical structure ensures compatibility with a wide range of thermoplastic systems.

Why Choose HP YELLOW 1349

HP YELLOW 1349 is optimized for plastics, where its superior heat stability and migration resistance outperform standard organic yellows. Unlike many organic pigments that degrade above 220°C, this grade withstands processing temperatures up to 260°C without significant color shift or strength loss. Its high opacity and brightness reduce the need for inorganic extenders, lowering formulation costs. Because there are no sibling grades in this product line, HP YELLOW 1349 stands alone as a dedicated plastics solution—no need to compare variants or worry about cross-grade compatibility. It excels in polyolefins, ABS, and engineering resins where color consistency is critical. The pigment’s low plate-out and warpage characteristics make it ideal for injection molding and extrusion applications.

Key Features

• Heat stable up to 260°C, maintaining color integrity during high-temperature plastics processing.
• Offers excellent migration resistance, preventing color bleed in flexible and rigid polymer matrices.
• Provides high opacity and tinting strength, achieving full coverage at lower pigment loadings.
• Exhibits outstanding dispersibility in polyolefins, ABS, and engineering thermoplastics without agglomeration.
• Ensures consistent batch-to-batch color strength and shade accuracy for reproducible results.

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“text”: “Pigment Yellow 191 (PY191) delivers excellent heat resistance up to 300°C, making it suitable for high-temperature polyolefin processing such as PP and PE injection molding where thermal exposure is critical. This monoazo calcium pigment lake maintains shade consistency without compromising polymer shrinkage. For ABS and PC applications at the upper processing window, PY191 ensures reliable tint stability without fading.”
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C.I.NO.: PY191

Advantage:

Main Application Recommended: Plastics

Product Description – PY191

HP YELLOW 1349 (PIGMENT YELLOW 191) is a monoazo calcium pigment lake with a reddish shade of yellow. It features excellent heat resistance, withstanding temperatures up to 300°C, good light fastness, and does not affect the shrinkage of polymers. It exhibits excellent solvent fastness in both aliphatic and aromatic hydrocarbons, as well as in commonly used plasticizers. It is widely applied in the plastics industry, including for materials such as HDPE, PVC, ABS, PC, PBT, and PP Fiber. Additionally, it is FDA-approved.

Recommended Application

Plastics: PP, PE, PVC, PS/SAN, ABS, PC, POM, PBT, PMMA, Rubber/TPV, SBC, TPO, TPU

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 PY191

What specific plastic applications is HP Yellow 1349 recommended for?

HP Yellow 1349 is primarily designed for high-performance engineering plastics, such as ABS, polycarbonate (PC), polyamide (PA), and polypropylene (PP). It excels in applications where high heat stability is critical, such as automotive interior components, electrical housings, and consumer goods requiring bright, durable yellow tones. Due to its high thermal resistance (up to 280°C for short durations), it is not ideal for low-end commodity plastics like LDPE, where simpler pigments suffice. It offers excellent lightfastness even in thin sections, making it suitable for outdoor or UV-exposed parts when formulated correctly. Always test in your specific resin system to confirm compatibility.

What are the key performance limitations of PY191 in plastics?

While PY191 offers outstanding heat stability (up to 260-280°C), its primary limitation is its sensitivity to strong reducing agents or highly alkaline environments, which can cause color shift towards greenish or dull shades. It also has moderate hiding power compared to inorganic yellows like lead chromate or bismuth vanadate; transparent or translucent effects may require higher loading (0.5-2% depending on resin). Additionally, PY191 is not recommended for direct food contact applications in high-temperature processing (e.g., microwaveable containers) without rigorous migration testing. Over-processing (excessive shear or prolonged residence time above 290°C) can cause partial decomposition, reducing chromatic strength.

How does HP Yellow 1349 compare to PY110 or PY83 for plastics?

HP Yellow 1349 (PY191) sits between PY110 (benzimidazolone yellow) and PY83 (arylamide yellow). Compared to PY110, it offers superior heat stability (280°C vs. 250°C) and better lightfastness in transparent applications, but PY110 has stronger tinting strength in opaque systems. Versus PY83, HP Yellow 1349 provides dramatically higher thermal resistance (PY83 degrades above 220°C) and much better migration resistance in polyolefins. However, PY83 is more economical and offers brighter greenish-yellow shades. For applications requiring a clean, strong yellow with good opacity at moderate costs, HP Yellow 1349 strikes the balance between performance and value, especially in ABS and PC blends.

What are the crucial processing conditions for PY191 in injection molding?

For optimal results with HP Yellow 1349, maintain melt temperatures between 220°C and 260°C for most engineering plastics, never exceeding 290°C to avoid thermal degradation. Back pressure should be moderate (5-10 bar) to prevent excessive shear which can fracture pigment particles and dull the shade. Drying the pigment masterbatch or pre-colored resin at 80-100°C for 2-4 hours is recommended to minimize moisture, which can cause splay marks or hydrolysis. Screw speed should be kept below 80 RPM to reduce localized overheating. For polycarbonate, use a lower temperature profile (230-250°C) to prevent yellowing or greenish shift. Always conduct a short-shot color check on first run parts.

Can PY191 be stored long-term or substituted with other yellows?

HP Yellow 1349 has excellent storage stability: store in a cool, dry environment (<30°C, <60% humidity) to prevent caking; shelf life is typically 3-5 years from production if unopened. It is not a direct replacement for PY138 (quinophthalone) or PY151 (benzimidazolone), as those have different chemical structures and solubility profiles. If substituting, PY191 often replaces PY81 (C.I. 21127) or PY185 (C.I. 21108) in high-heat polyamide applications due to superior bleed resistance. However, substitution requires full reformulation testing—especially for heat retention and warpage—as PY191 has lower aspect ratio than some alternatives. For temporary substitution in non-critical applications, PY110 can be used at 1.2x loading to approximate shade.

HP Yellow 1349 Takeaway

HP Yellow 1349 delivers high-performance coloration for demanding engineering plastics, combining outstanding thermal stability (up to 280°C) with excellent lightfastness and migration resistance. It bridges the gap between cost-effective organic yellows and premium high-heat pigments, making it ideal for automotive, electrical, and durable consumer goods. While careful processing and resin-specific testing are required, its reliability across polycarbonate, ABS, and nylon applications makes it a top-tier choice for achieving bright, stable yellow tones. For consistent, professional results in challenging plastics, HP Yellow 1349 is the pigment you can trust.

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