Industrial dyes are quite often used in multiple industries these days; so is the case with pigments. If we talk about industrial dyes, they are basically coloring, ionizing, and aromatic compounds that are used in numerous applications across various industries. Dyes have the property to show an affinity towards the substrate. But, they should be used cautiously because some industrial dyes are toxic and carcinogenic in nature. Anyway, at present, dyes found their application in industries like plastic, cement, cosmetics, rubber, paper, textiles, medicine, to name a few. Some primary varieties of industrial dyes are mentioned under:
1) Digital Textile Printing Dyes: In digital printing, computer controlled ink-jet nozzles or charged drums are used. The physical surfaces over which the digital prints are reproduced include common paper, photographic paper, plastic, cloth, etc. The popular varieties of dyes used for this purpose are acid inks, disperse inks, reactive inks, and dye based inks.
2) Leather Dyes: Tanneries usually make use of around 50-100 different varieties of leather dyes. Each dye produces a diverse desired effect over the leather. The dyes used in this industry include direct, acid, mordant, reactive, and basic dyes, among others.
3) Optical Brighteners: Also known as optical agents, optical brighteners are the dyes that possess the attribute of absorbing the violet and ultraviolet region of the electromagnetic spectrum, which results in the prominent re-emission of light in the blue region. This dye is not suitable to be used in water (like in aquarium, etc.), due to its toxic nature.
4) Sublimation Dyes: These dyes primarily found their application in various types of printing. They can be found in several forms like inkjet inks, ribbons for thermal transfer, and toner for laser printers. Sublimation dyes are applied by the process called heat-transfer. Their main varieties include acid, disperse, vat, direct, and reactive.
Now, as you might have got some idea about the industrial dyes and their primary varieties, let's discuss about industrial pigments and their types. Pigments are basically the materials that make a modification in the color of the transmitted light owing to their attribute of selective absorption of the wavelength. The change in the transmission of light varies with fluorescence, phosphorescence, as well as with other forms of luminescence, in which a material emits light. Pigments are generally used in inks, coloring paints, cosmetics, eatables, etc. Nowadays there are various types of pigments available in the market, out of which some primary types of pigments are given under:
1) CLC Pigments: Cholesteric Liquid Crystal (CLC) pigments are made from CLC films. These pigments are nowadays increasingly used in security machines and also as an impediment to the counterfeit of currency notes, legal documents, etc.
2) Fluorescent Pigments: These pigments have the quality of changing the ultraviolet light into the desired color. They form the vital element of any kind of fluorescent material. The fluorescent pigments are mostly used in textile field, solvent based paper coating, and paints and aerosol coating.
3) Organic Pigments: Organic pigments consist of solid particles and they are insoluble in the application medium. There are two basic varieties of these pigments, namely natural and synthetic. Organic pigments are generally used for coloring or coating purposes (both decorative and protective) on plastics, candles, paper, rubber materials, pharmaceuticals, etc.
4) Ultramarine Pigments: They are a kind of inorganic pigments, which are non-poisonous and non-irritating in nature. They are also one of the oldest varieties of pigments. They have two basic types, viz., ultramarine blue and ultramarine violet. Ultramarine pigments found their application in coating, coloring, printing inks, cosmetics, and artist colors.