Phthalocyanine green, also known as Pigment Green 7 or PG7, is a synthetic green pigment derived from phthalocyanine blue. It is one of the most widely used green pigments due to its excellent properties.
Chemical Formula: C32H3Cl15CuN8
Molecular Weight: 1029.78 g/mol
Appearance: Bright green crystalline powder
Solubility: Insoluble in water and most organic solvents
Synthesis
Phthalocyanine green is synthesized by chlorinating copper phthalocyanine (phthalocyanine blue). This process introduces chlorine atoms into the molecule, resulting in the green hue.
Paints and Coatings: Extensively used in decorative paints, industrial coatings, and automotive finishes due to its vibrant color and durability.
Printing Inks: Widely used in various printing processes, including gravure, flexography, and screen printing, due to its excellent dispersion and stability.
Plastics: Used to color plastics and polymers because of its resistance to heat and chemicals.
Textiles: Employed in dyeing and printing textiles, offering high fastness properties.
Cosmetics: Used in certain cosmetic formulations that require green pigments.
Artists’ Colors: Preferred by artists for its bright, stable green hue in oil, acrylic, and watercolor paints.
High Tinting Strength: Provides strong coloration with minimal pigment.
Lightfastness: Highly resistant to fading when exposed to light.
Chemical Stability: Resistant to acids, alkalis, and solvents, making it suitable for various applications.
Non-toxic: Generally considered safe for use in consumer products.
Environmental and Safety Considerations
Phthalocyanine green is considered non-toxic and environmentally benign. However, standard safety precautions should be followed to avoid inhalation or prolonged skin contact, which could cause irritation.
Phthalocyanine green was developed after the success of phthalocyanine blue in the mid-20th century. The introduction of chlorine atoms to the phthalocyanine structure provided a new, stable green pigment with superior properties compared to earlier green pigments.
In summary, phthalocyanine green is a highly versatile and durable pigment used in a wide range of applications, offering excellent performance characteristics and safety.
