C.I. pigment red 170

C.I. Pigment Red 170 (CAS 2786-76-7) is a monoazo pigment also known as Naphthol Red, PR170, and commercially as F5RK and F3RK grades, with the colour index number 12475. It is a synthetic organic pigment produced by coupling a diazonium salt with a naphthol derivative, yielding a red powder with strong tinting strength.

In plastics, PR170 is used to colour polyolefins and engineering polymers, where its heat stability allows processing at elevated temperatures without significant shade shift. In printing inks and packaging coatings, it provides high opacity and resistance to bleed, making it suitable for solvent-based and UV-cured systems where colour consistency across substrates is critical.

PR170 is supplied as a dry powder and is subject to REACH registration requirements for EU market supply. Grades vary in particle size distribution and surface treatment, affecting dispersibility in different media. Buyers should confirm grade specification against their dispersion system and end-use regulatory requirements.