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Dope dyeing: In dope dyeing, pigments are added to the polymer solution itself before extruding the fibers. The process provides the dyed fibers with excellent fastness properties. The dope dyeing applies to synthetic fiber only.
Solution dyeing, also known as dope or spun dyeing, is the process of adding pigments or insoluble dyes to the spinning solution before the solution is extruded through the spinneret. Only manufactured fibers can be solution dyed.
Although almost all dyeing can be done in a vat, the term vat dye is used to describe a chemical class of dyes that are applied to cellulosic fibre (i.e., cotton) using a redox reaction as described below. Because of the use of caustic soda, and the very high pH of the dye bath in the dyeing process, wool cannot be dyed using vat dyestuffs.
"Lyocell" has become a genericized trademark, used to refer to the Lyocell process for making cellulose fibers. [ 3 ] [ 6 ] The U.S. Federal Trade Commission defines Lyocell as "a fiber composed of cellulose precipitated from an organic solution in which no substitution of the hydroxy groups takes place, and no chemical intermediates are formed".
A dye is a colored substance that chemically bonds to the material to which it is being applied. This distinguishes dyes from pigments which do not chemically bind to the material they color. Dye is generally applied in an aqueous solution and may require a mordant to improve the fastness of the dye on the fiber. [2]
In a reactive dye, a chromophore (an atom or group whose presence is responsible for the colour of a compound) contains a substituent that reacts with the substrate. Reactive dyes have good fastness properties owing to the covalent bonding that occurs during dyeing. Reactive dyeing is the most important method for coloring cellulose fibers.
The safety of Red Dye No. 3 is not something that the average person needs to be concerned with, unless their diet is comprised mainly of maraschino cherries, red decorating icing, and Valentine ...
Cudbear is one of the few natural dyes to be credited to a named individual, Dr Cuthbert Gordon of Scotland, who patented the process of its production in 1758. [8] cutch Cutch is an ancient brown dye from the wood of acacia trees, particularly Acacia catechu, used in India for dyeing cotton. Cutch gives gray-browns with an iron mordant and ...