Colorants are mainly categorized into three types: organic pigments, dyes, and inorganic pigments. This article focuses on the differences, classifications, properties, and application scenarios of organic and inorganic pigments, providing valuable insights for industries such as plastics, coatings, and inks.
Pigments are primarily divided into inorganic pigments and organic pigments, distinguished by their molecular structures.
Composed of inorganic substances (without carbon elements), such as metal oxides, chromates, carbonates, sulfates, and sulfides. They are further classified by color into:
- Achromatic pigments: Covering white, gray, and black (e.g., carbon black, titanium white, zinc white).
- Colored pigments: Including red (iron oxide red), yellow (lead chromate, cadmium yellow, iron yellow), green (chromium oxide green, lead chrome green), blue (iron blue, cobalt blue, ultramarine), and brown pigments.
Containing carbon elements (with carbon ring or carbon chain structures), they are derived from natural or synthetic organic compounds. Classified by chemical structure, the key categories and their proportions are:
- Azo pigments (59%): The largest category, accounting for ~60% of total organic pigment production. It includes insoluble azo pigments, azo dye lakes, and condensed azo pigments, with a wide color range (yellow, orange, red, brown, blue).
- Phthalocyanine pigments (24%): High-grade pigments emitting blue-green light, mainly including metal-free phthalocyanine, copper phthalocyanine (dominant in industry), and cobalt phthalocyanine. They have excellent heat resistance, light fastness, and are widely used in inks, plastics, and rubber.
- Triarylmethane pigments (8%): Featuring bright colors and good tinting strength.
- Special pigments (6%): Such as functional phthalocyanines with catalytic or photoelectric conversion properties.
- Polycyclic pigments (3%): Including heterocyclic and fused ring ketone pigments (e.g., quinacridones, diketopyrrolopyrroles, perylenes).
The two types of pigments differ significantly in composition, properties, stability, and application scenarios, as detailed below:
A comprehensive performance comparison is shown in the table:
2.3 Application Scenarios
Inorganic pigments excel in weather resistance, heat resistance, and cost-effectiveness, making them ideal for construction, anti-corrosion, and high-temperature scenarios. However, they have limitations in color range and toxicity (due to heavy metals).
Organic pigments, with their bright colors, wide color gamut, and low toxicity, are preferred for high-end applications like printing inks, automotive coatings, and plastics. While common organic pigments have lower heat/light fastness, high-performance varieties (e.g., phthalocyanines, quinacridones) match or exceed inorganic pigments in durability, expanding their application scope.
As a crucial fine chemical product, the variety, output, and application of organic pigments continue to grow, driving innovation in industries such as plastics, coatings, and inks.
For more information about Shenhong Pigment's iron oxide pigments and cooperation opportunities, please contact us via the following channels:
- Head Office Address: No. 1 of Lane 185, South Anxie Road, Jiading District, Shanghai, China
