Inorganic effect pigments

US11680169B2 · kind B2 · utility

Assignee

• SUN CHEMICAL B.V. · NL

Inventors

• Benjamin Mohr · Ludwigshafen, DE
• Christopher Sichmeller · Elmsford, US

Key dates

• Filing date: Apr 4, 2017
• Grant date: Jun 20, 2023
• Expiry date: Apr 4, 2037

Classification

• Technology area (CPC C): Chemistry; Metallurgy
• CPC primary: C09C2220/106
• WIPO field: Pharmaceuticals
• WIPO sector: Chemistry

Abstract

An inorganic, non-quarter wave, heterogeneous multilayer effect pigment includes a platy substrate comprising an absorbing optically active metal oxide layer thereon, having an optical thickness from about 20 nm to about 400 nm; a layer of low refractive index material on the absorbing optically active metal oxide layer and having an optical thickness from about 10 nm to about 500 nm; and an outermost optically active layer of a non-absorbing high refractive index material on the low refractive index material and having an optical thickness from about 50 nm to about 1000 nm. The multilayer effect pigment exhibits a blue reflectance ratio (BRR) of at least 3, according to the equation: BRR=(Blue Max)/(Green Min); where Blue Max is the maximum reflectance exhibited over wavelengths 380 nm to 450 nm; and Green Min is the minimum reflectance exhibited over wavelengths 450 nm to 600 nm.