pretreatment process of silk

Pretreatment of Silk

Md Alamin Munshi

Department of Textile Engineering

Southeast University (SEU)

Email: Alamin_munshi@gmail.com

Pretreatment of Silk

This means a few treatment, which is done before (dyeing and printing) actual process. For the preparation of silk son and dye of silk materials for dyeing and publishing, it is necessary to withdraw a part or all sericin, because well as raw anoints and organic impurities. Depending on the proportion of sericin absented during scouring (sericin present in raw silk in the proportion of 20% to 25%),
the final intersection is defined as not pickled (only used for shirts and suits), ` soft "or degummed.

1. Cleaning
2. Ovulate

Degumming of silk

It is known that the elimination of "the process of gum (sericin)" raw silk and silk degumming. Degumming silk primarily involves the removal of fibroin sericin. Sericin is soluble in water. And where is relatively easy degradable protein molecule is divided by a long sericin into smaller parts, which easily dispersed or dissolved in hot water.

silk

Silk

Practiced degumming with soap in the bearing of a mild alkali such as sodium carbonate. Degumming with alkali is a office of pH scale, temperature and length of treatment. PH must remain in leve1 9.5 to 10.5. If the level is less than ninety-five, then the formula of absenting sericin will be slow. If the pH is greater than 10.5, it will be a significant increase in weight loss.

degumming loss in this process is usually 20-25%. In some cases it has not been removed full silk gums, but is flexible enough removed only to make it shiny and applicable to dyeing and silk laundering. This is known as "Soupling" which are removed only 10% to 15% of the gum. In addition to eliminating dirt and additives used in silk weaving, scouring absents some sericin (gum) that are still on silk. Often allowed amount of natural glue that cadaver on the fiber silk to give it extra body and make it lighter to manage in birling and weaving.

Bleaching of silk

Silk contains colored silk material with natural coloring pigments yellow green brown and yellow. During degumming remove sericin matt white silk Results lightly colored materials. Some occupied for nearly fibroin sericin, complete elimination of color by removing the gum is not potential. During laundering and discolored these natural dyes / Remove producing the substance pure white. To be effective bleaching process to ensure the level of pure whiteness and stain and deterioration of non-material. Whitening is based about the use of reducing agents either silk or oxidizing agents.

Some of the agents is important to reduce used for bleaching are:

1. sodium hydrosulphite (hydroureter)
2. Sulfur dioxide
3. Sodium / formaldehyde sulfoxylate zinc

Agents within this delay tend to minimize oxidation of the original color can be restored by bleached materials.

Popular oxidating factors used for silk laundering were:

1. Hydrogen peroxide
2. Potassium permanganate
3. Sodium perborate
4. Sodium peroxide