BOOK_CONTENT
From Common Dyes and Their Properties

Classification of Dyes

Dyes are classified based on their origin, application, and chemical properties. Dye manufacturers classify dyes according to their chemical properties, while dyers classify dyes based on the method of application.

Classification Based on Origin of Dyes

Most dyes are organic molecules and are complex in nature. The synthesis of organic dyes began with azulene synthesis. Before that, colors were made from pigments.

As a result, dyes can be classified as natural and synthetic, according to their sources of origin.

Natural Dyes

Natural dyes are derived from nature through organic and inorganic materials or sources. Logwood is a natural dye obtained from plants. It saturates silk, wool, cellulose acetate, and nylon with a deep black color. Tyrian purple is obtained from animals and Prussian blue is an inorganic dye obtained from naturally occurring minerals.

Synthetic Dyes

Synthetic dyes became popular because they were easy-to-use, less expensive and had wider range of colors. Synthetic dyes are obtained by adding chemicals to natural dyes. For example, artificial alizarin is a synthetic dye synthesized from coal tar anthracene. Synthetic dyes are used for modern clothing.

Classification Based on the Dyeing Process

Dyeing process is accomplished by dissolving or dispersing the colorant in a suitable solution (usually water) and bringing this system into contact with the material to be dyed. According to the process of dying, dyes are classified into the following types:

  • Acid

  • Basic

  • Mordant

  • Direct

  • Reactive

  • Vat

  • Disperse

  • Sulfur

  • Azo

Acid Dyes

Acid dyes are anionic dyes soluble in water.

Copyright 2006 under license agreement with Books24x7

Products & Services
Air Valves
Air valves allow metered fluid flow in one or both directions. They are used in pneumatic circuits to regulate the rate of activation or exhaust of cylinders and other pneumatic devices.
Plastic Valves
Plastic valves are made from plastic materials and are used in applications that require corrosion resistance and/or chemical handling.
Diaphragm Valves
Diaphragm valves close by means of a flexible diaphragm attached to a compressor.
Globe Valves
Globe valves are linear motion valves with rounded bodies, from which their name is derived.  They are widely used in industry to regulate fluid flow in both on/off and throttling service. 
Water Valves
Water valves are designed to handle and control hot water, cold water, ground water, potable water, salt water and/or wastewater. They are made from metal or plastic.

Topics of Interest

Bonding of a Dye to Fiber The process of dyeing depends not only on the type of the dye but also on the type of fiber. Fibers can be natural or synthetic. Natural fibers are cotton, linen, flax, hemp...

3.1 Introduction to Manual Valves 3.1.1 Definition of Manual Valves By definition, manual valves are those valves that operate through a manual operator (such as a handwheel or handlever), which are...

Fluid Solidification Protection Jacketed Valves and Fittings Jacketed valves are used for conveying petroleum residues, tars, waxes and other solutions which are either extremely viscous or semisolid...

Determining flow capacity is a critical factor in valve selection. Directional-control valves are common in pneumatic systems. They control compressed-air flow to cylinders, rotary actuators,...

Overview Directional control valves are primarily used to control the direction of flow between the components of a pneumatic circuit. Due to their internal resistance they also throttle the air...

Product Announcements
Festo Corporation
Clippard Instrument Laboratory, Inc.
SC Hydraulic Engineering Corporation