Wednesday, December 16, 2009

Textile Pretreatment

Pretreatment

Means any treatment, which is done before actual (dyeing and printing) process.
Natural fibers and synthetic fibers contain primary impurities that are contained naturally, and secondary impurities that are added during spinning , knitting and weaving processes.Textile pretreatment is the series of cleaning operations.All impurities which causes adverse effect during dyeing and printing is removed in pretreatment process.
Pretreatment processes include desizing, scouring, and bleaching which make  subsequent dyeing and softening processes easy. Uneven desizing, scouring, and bleaching in the pretreatment processes might cause drastic deterioration in the qualities of processsed products, such as uneven dyeing and decrease in fastness.
Objective of Pretreatment
*  To Convert  fabric from hydrophobic to hydrophilic state.
*  To remove dust, dirt etc from the fabric.
*  To achieve the degree of desire whiteness.
Steps in Pretreatment Process of cotton and natural fibers
Major steps involved in textile pretreatment are,
1.Singeing
2 Desizing,
3. Scouring,
4. Mercerization
5. Bleaching.
6.Singeing
Introduction to Textile preparation : Slide Show

Steps in pretreatments for  wool are:
1.Raw wool scouring; aqueous and/ or solvent washing 
2.Carbonizing
3.Scouring (desizing)
4.Fulling /crabbing/thermo fixing
5.Easy-care treatments
6.Anti-felting anti-shrinking treatments
7.Wool Bleaching
Steps in pretreatment of Silk
To prepare a silk yarn for dyeing and silk fabrics for dyeing and printing, it is necessary to partially or completely remove sericin, as well as natural oils and organic impurities. Depending on the percentage of sericin removed during scouring (sericin is present in raw silk in a ratio between 20 % to 25 %), the end-product is defined as unscoured (used only for shirts and suits), `souple' or degummed.
1.Degumming
2.Scouring
3.Bleaching
Pretreatment Of Synthetic Textile Materials
Although mots of the synthetics do not need to be given a very strong pretreatment however the possible steps in pretreatment of synthetics are 
1.Desizing
2.Heat setting
3.Washing
4.Bleaching if necessary.

Read articles
Better ways to pretreat fabrics
New trends in continuous pretreatment
Enzymatic pretreatment of cotton wovens
Economic impact analysis of pretreatment standards for the textile industry
Pretreatment of textile wastes: Seminar for Upgrading Textile Operations to Reduce Pollution, Atlanta, Georgia, September 25 and 26, 1973
Economic impact analysis of proposed effluent limitations guidelines, new source performance standards and pretreatment standards for the Textile Mills Point Source Category (EPA440/279020)
Economic impact analysis of proposed effluent limitations guidelines, new source performance standards and pretreatment standards for the Textile Mills Point Source Category (EPA440/279020)

2 comments:

  1. sir please can u describe the process of cotton scouring in detail such as surface tension, emulsification and detergency which happens during scouring

    ReplyDelete
  2. Really your information is helpful.

    ReplyDelete

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