Pigment

Pigment Orange 34 (C.I. 21115, CAS 15793-73-4)
It is a classic bisazo pyrazolone organic pigment, commonly known as Benzidine Orange or Permanent Orange RL. It exists as a bright reddish-orange powder with high tinting strength and excellent dispersibility, and is widely used in inks, coatings, plastics and rubber. In recent years, research has focused on formulation modification and performance enhancement.

Characteristics of Pigment Orange 34

Tinting Strength and Processability
It features high tinting strength and easy dispersibility, along with good transparency and gloss. Compatible with multiple systems and processes, it enables fast and uniform coloring.
Balanced Fastness Properties
It exhibits excellent water fastness, detergent fastness and vulcanization resistance; moderate solvent fastness with stability to most common solvents; and superior light fastness and migration fastness compared with Pigment Orange 13, making it more reliable for outdoor applications and flexible PVC.
Cost-Effectiveness and Substitutability
It boasts high cost-performance and can replace molybdate orange in agricultural machinery and architectural coatings, reducing reliance on heavy metals.
Limitations
It tends to decompose at high temperatures (>200℃) and has moderate weather fastness. It is recommended to be used with light stabilizers for long-term outdoor applications.

Main Application Fields of Pigment Orange 34

Ink Industry
It is applicable to offset inks, water-based inks, solvent-based inks and packaging inks, compatible with flexographic and gravure printing processes, and is particularly suitable for high-gloss packaging printing.
Coatings and Painting
It is used in industrial coatings, architectural coatings, powder coatings and automotive primers, and can replace molybdate orange to reduce environmental risks.
Plastic Coloring
It is suitable for flexible PVC, polyolefins (PE/PP), EVA, etc. It remains stable with no obvious migration when processed at temperatures ≤200℃.
Rubber and Elastomers
It is applied in natural rubber, synthetic rubber and latex products. With vulcanization resistance and non-migration properties, it is compatible with various vulcanization processes.

Other Applications

It can be used in paint printing pastes, leather coloring, stationery and educational supplies, etc.

Latest Research and Findings of Pigment Orange 34 (2023-2025)

Formulation Modification and Dispersion Optimization
Core-shell Structured Predispersions: Core-shell type PO34 is prepared with polyethylene wax as the shell. This modification significantly improves hydrophobicity and dispersibility, shortens filtration time by 60%, and reduces filter cake moisture content to 49.0%, making it suitable for color masterbatch production and high-efficiency processing.
Microencapsulation: PO34 is encapsulated via in-situ polymerization, which increases heat resistance up to 220℃, reduces migration risk, and expands its application in high-temperature processing scenarios.
Crystal Structure and Performance Mechanism
3D electron diffraction technology has revealed its crystal structure, and a reversible solid-state phase transition at 180-220℃ has been discovered, providing theoretical support for heat resistance optimization and processing window design.
Surface Modification: Treatment with silane coupling agents enhances the interfacial bonding with resins, improving weather fastness and color fastness.

Environmental Protection and Application Expansion

Heavy Metal-free Formulations: Promoting the substitution of molybdate orange in industrial coatings, which complies with EU RoHS and REACH standards.
Water-based System Compatibility: Water-based dispersions have been developed to reduce VOC emissions, meeting the requirements of environmentally friendly inks and coatings.
V. Application Precautions
Control the processing temperature below 200℃ to avoid shade deviation or decomposition.
Use with light stabilizers in outdoor applications to improve weather fastness.
Pay attention to compatibility and migration risk when compounding with other pigments.