Direct dyes for yarn are water-soluble anionic dyes and retain sulfonic acid groups in the structure. They are directly taken up by the fibers. In 1883, found synthetic direct dye which was Direct Yellow. In 1956 found natural color as, "Anionic dyes substantive to cellulose when used from a liquid bath having electrolytes."
Dyes are retained on the fiber by hydrogen bonds and van der Waal forces. Though the light fastness of Direct color is great yet the clean fastness endures a whole lot. The dye particles are small and water-soluble, so it shows poor damp fastness. Though it can be boosted by after-treatments.
These dyes are superior to others in terms of price, better light fastness, ease of application, shorter color cycle, affordable accessories, incredibly lesser use of water, and lower salt level in the effluent.
Why Are Direct Dyes so called?
Direct dye is called as a result of the adhering to factor:
1.Direct dyes can be applied directly to the textile and do not need any aid.
2.Direct dyes are anionic and have substantivity for all sorts of cellulosic fibers. Instance Cotton fiber, viscose rayon, etc
Properties of Direct Dye:
•Direct dye is soluble in water
•It is an anionic in nature
•It is one of the most substantive dye
•Required electrolytes for exhaustion
•It is suitable for cellulosic and fibers
•Need after therapy
•Clean fastness is not good
•Color Fastness is typical
•It is dyed in an alkaline medium
•It is affordable
Direct dyes work on woolen, natural leather, paper, silk, cotton, and nylon. They are also beneficial as pH indicators and as organic spots.
Do you know about the paper industry?
Paper industries have been broadly using the forms of dyes for the last hundreds of years. By seeing the development in the paper industry, it can be safely thought that dyes for the paper industry have a very promising future. Provided list below is an extensive check of different qualities of paper that are open to dyeing.
•Writing and printing paper
•Photocopier documents
•Decorative paper
•Cells such as toilet, towel, napkin, or face
•Boards and cover papers
•Envelopes. Tag, washing bags, and posters
•Product packaging papers
The useful dyes have cationic direct dyes and sulfur dyes. Other than these two alternatives, acid dyes and standard dyes are also useful. Sulfur dyes are lowered alkaline remedies. For an instance to get the direct dye-- their experts do a few chain reactions and bring the dye shade. So if talking about cationic direct color, a couple of attributes that make it appropriate for use in the paper are--.
•A planar molecular structure
•A prolonged conjugation.
•An unwanted favorable charge over the negatively charged surface teams.
What are the criteria to choose a color?
•Propper shade
•Affinity
•Lightfastness
•Showing hemorrhaged fastness
•Offers security to moisture and temperature.
•Lower or otherwise whatsoever metamerism.
•Safe to deal with.
•No effect on any other paper process or criteria.
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