Mercerizing cloth

Cotton print-cloth, mercerized under tension Direct Oct.-April 6 mo 14... 

Cotton can be causticized or half-mercerized to increase the dye uptake and economics up to 25% may be realised. Semi-mercerization or causticization is carried out in caustic soda solution between 25 and 30 Tw at a temperature of 20-25 C, sometimes without stretching the cloth to restore original dimensions. Sodium hydroxide solution above 30 Tw the rate of colour absorption decreases. Semi-mercerization is also an important step where heavy shades are required with the expensive vat colours. Better results are also observed with aniline black on goods which have received a semi-mercerization treatment. 

Mercerization with alkali can be carried out in the cloth (woven and knitted) form and in the yam (hank) form. Mainly two systems i.e. chain and roller mercer-... 

A typical clip chain mercerizing machine for woven cloth is shown in Fig. 9-6. In this type of mercerizing machine shrinkage is allowed in the primary stage of the... 

Figure 9-18. Dimensa mercerizing machine cloth run diagram. 1. impregnating zone 2. cooling and reaction zone 3. stenter frame 4. stabilizing zone 5. washing and neutralising zone.

Application of foamed alkali liquor on the cloth can produce one sided mercerization and differential dyeing [79]. 

Hanks are mercerized on a machine of the type illustrated in Fig. 3.15, although there are many other designs. The hanks, which have been scoured previously, are placed over arms which apply tension. They then rotate the yarn, at the same time themselves moving in an arc to immerse the cotton in a caustic soda solution of specific gravity L3, equivalent to 27 per cent concentration. After a few minutes the arms move to another position, where the bulk of the alkali is rinsed out before tension is removed. A further movement accompanied by relaxation of stretch permits removal of the hanks, which are then rinsed in acetic acid and thoroughly washed T with water. A mercerizing machine for open-width cloth is shown in g. 3.16. 

The action of caustic soda can be used to produce pattern effects. If applied locally without tension the fibres contract and a puckered finish is produced. If a pattern is printed with a paste containing little or no water, and the cloth is then passed through water under tension, a lustrous design appears on a matt background. When dyea, the mercerized portions will be a heavier shade than the remainder. 

So-called because it was discovered by the Lancashire textile chemist John Mercer in 1844, who found that passing cotton thread through a bath of caustic soda gave the resultant cloth an attractive sheen. 

Finishing refers to any process performed on textile materials to improve the look, performance, or hand of the finished textile or clothing. Some finishing techniques, such as fulling, have been in use with handweaving for centuries others, such as mercerization, are byproducts of the Industrial Revolution. 

In the 1840s, John Mercer noted that when strong caustic soda solutions were filtered through cotton fabric, the cloth shrank, had greater thickness and strength and increased dyeing capacity. 

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