Textile Knowledge : Fibre

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Azoic Dyes

The dyes which contain insoluble azo group(-N=N-) are known as azoic dyes. These dyes are not found in ready-made form. They dyes are produced through an in-situ process which created colored material directly on the fabric by a reaction between two compounds namely

1. Diazo compound or diazo base

2. Coupling compound i.e. Naphthol

Azoic dye is one type of ingrain dyes .e. it is produced during dyeing process inside the fibre. The general reaction of azoic dye formation is given below:

R-N=N-Cl + R`-ONa R-N=N-R`

Diazo compound Naphthol Azoic color

The diazo compound is very often said fast base or diazonium salt of fast base.

The colored substance formed from essential colorless compound is insoluble in water and the washing fastness of this shade is excellent. But it has poor rubbing fastness. Johann Peter Griess of German discovered the diazotized reaction and subsequent reactions of a diazotized reaction in 1858. This discovery was the foundation stone for the immerse edifice of azo dyes. He found that Premuline can be diazotized on the fiber which afterward takes part in couple reaction with an aromatic hydroxyl or amino compound to give a new dye of greater wet fastness.the oldest application of this method was in the dyeing of para red. This para red was produced by coupling diazotized p-notro aniline with β-naphthol. the formation of an insoluble azoic pigment was first patented by Thomas and Holliday in 1880.

Properties of Azoic Dyes click here

Azo Dyes click here

Azoic Dyes click here

Chemistry of dyeing with Azoic Dyes click here

Sequence of operation for dyeing with Azoic dyes click here

Method of dyeing with Azoic Dye click here

Color performance of Azoic dyeing click here

Problem in dyeing with azoic color click here

Protein fibres are not dyed with Azoic dyes click here

Hemp

In many parts of Asia, the fiber hemp has been in use since prehistoric times. Ancient records describe the use of hemp in China in 2800B.C. During the early Christian era, production of hemp spread to the countries of Mediterranean Europe, and since then the fiber has come into widespread use throughout the world.

Like flax, hemp is a bast fiber. It comes from the plant Cannabis sativa, an annual of the family Moraceae, which grows to a height of 3m or more.

The hemp plant is now cultivated in almost every European country, and in many parts of Asia.

Important producing country including the Soviet Union, Yugoslavia, Romania and Hungary.

Hemp click here

Varieties of hemp click here

Chemical composition of hemp click here

Production and processing click here

Dyeing click here

Hemp in use click here

Jute

In common with other bast fibers, jutes has been used by man since prehistoric times. It comes from the inner bark of plants of the genus corchorus, which probably originated in the mediterranean area and was subsequently taken to india where it now grows profusely. Jute fabrics formed the ‘sackcloth’ of bibical times.

The jute plant flourishes in hot, damp regions of asia, and jute has for centuries been grown in enormous quantities for textile purposes. It is now produce in greater quantity than any textile fiber other than cotton

During the latter half of the eighteenth century, the first shipments of jute reached western europe from india. In 1820, jute was spun experimentally at abingdon near oxford. The new fiber was of immediate interest to the flax and hemp spinners located at dundee in scotland. The napoleonic wars had cut off supplies of hemp and flax from russia, and the dundee mills began spinning jute in 1822. After ten years of experiment, the dundee manufacturers were able to spin jute satisfactorily, and by 1850 the jute industry was well established. It was given further encouragement by the crimean war which cut off hemp and flax supplies in 1853, and by the american civil ear of 1861-65 which interrupted took up the spinning and weaving of jute, dundee has remained a centre of the industry. Meanwhile, india and bangladesh have been steadily increasing the number of jute spinning and weaving mills, and both countries are now processing much of their own fiber.

Jute fibre click here

Jute producing area click here

Chemical composition of jute fibre click here

Properties of jute fiber click here

Features of jute fiber click here

Jute gradation click here

Factors affecting gradation of jute clich here

Kutcha grading of jute click here

Production and processing of jute click here

Bleaching and Dyeing jute fibre click here

End uses of jute goods click here

Fibre click here

Textile fibre click here

Staple fibre click here

Filament click here

All fibres are not textile fibres click here

Cotton fibre

Raw cotton contains cotton fiber along with small plant parts and field trash that are not removed by the ginning process. At this stage, the cotton fiber has a coating of oils and waxes that make it hydrophobic. Raw fiber is suitable for making nonwovens to be used in industrial products in which absorbency and aesthetics are not important. In some cases, nonwoven fabrics made with raw fiber can be wet processed in the same manner as woven and knitted fabrics.

Cotton is the most important apparel fiber. It is important because of its many favorable properties. One of these properties is the care of cotton. When we use talk about care we are referring to the measures required to keep the cotton's or any other textile's original appearance. One reason for cotton's popularity is its easy care properties. Cotton is a hydrophilic fiber is very absorbent. Cotton has a poor resiliency which means that it wrinkles very easily.