Problems in Garment Dyeing

With today’s exploding clothing markets of leisure , casual wear and sports wear , garment wet processing has emerged as one of the best production routes towards meeting the quick changing fashion markets.

Unlike fabric or yarn as a substrate , a garment is not a uniform in texture ,it is full of thick places like seams , multilayered sites like pockets , cuffs and shoulders. At times certain unevenness like puckered seams lend a distinct style often highly valued but it could result into rejection of goods at other times .

Here we will try to figure out certain key problems associated with garment dyeing and their possible causes, so that a garment can analyze and overcome these problems. 

Garment size control and appearance

• variations in yarn size / twist
• ends per inch
• picks per inch
• courses per inch in the knitted fabrics   

Spirality in Knitted Fabrics 

 

• Twist of the yarn
• Fibre parameters,
• Yarn formation system,
• Yarn geometry,
• Knit structure
• Fabric finishing.            

Poor tear strength of garment

• Degradation of cotton during
• pretreatment,
• dyeing and
• finishing  such as stone /enzyme washing.

Pilling

• Low twisted yarns.
• Use of low staple length, cheaper fibre in manufacture of yarns
• Surface friction of fabrics/garments during wet processing and handling
• Reworking of  goods
• Cylinder rotation is too high.
• Liquor ratio is too low.
• Excessive cycle time

Puckering of seams during dyeing

• Improper selection of stitching thread.
• Due to high twist in sewing thread
• High residual and wet  shrinkage of sewing threads
• High stitching tension and improper stitch length..

Poor Rubbing fastness

• Improper washing and soaping treatment after dyeing.
• Too much unexhausted dye in dyebath.
• Loosely held surface indigo dyes
• Considerable back staining in each step
• Exposure to atmospheric ozone

Poor light fastness  

• Use of reactive dyes which are not light fast
• Use of formaldehyde based dyefixing agents

White, undyed or light seams

• Use of improper thread such as polyester thread on cotton garments.
• Use of mercerized thread on unmercerized garments.
• Mixing of different types of threads such as mercerized and un mercerized .
• High tension stitching .
• Unmatched Shrinkage behavior of  garment and thread .

Dullness around Metallic fittings

• Corrosion and chemical reaction between metallic parts in
• Pretreatment
• Bleaching
• Dyeing
• Finishing

Streakmarks/ Lines / Creases

• Overloading of machine
• Friction between Garments
• Entanglement of garments.

Shade nonuniformity

• Differences in fabric preparation processes like
1. Desizing,
2. Scouring
3. Bleaching.
• Inconsistency in the garment assembly

Poor Dye Yield

•   Garments contain a finish, softener, or an optical brightener.
•    Garments were allowed to dry out after pretreatment stage
•    Liquor ratio is too high.
•         Agitation is too slow.
•         Excessive washing between cycles.
•         Excessive time spent in any cycle.
•         Too much/too little pretreatment.
•    Not pretreated for correct time and/or temperature.

Blotchy or Non-Uniformly Dyed Garments

• Garments contain a finish, softener, or an optical brightener.
•  Liquor ratio is too low (want 20:1). 
•  Excessive bath temperature at beginning of pretreat or dye cycle.
•  Dye bath temperature ramped too quickly .
•  Improper addition or dilution of dyes/chemicals.
•  Live steam injection into bath.
•  Hard water.
•  Garments not scoured properly
•  Garments were allowed to dry out after pretreatment stage 
•  Garments not allowed to wet-out sufficiently before adding pretreatment.
  

           

Patchy dyeing

• Starting temperature too high
• Heating rate too High
• Salt addition at high temperature
• Addition of dyes and chemical at once

Spotting

• Formation of foam
• Improper washing
• Machine not clean.
• Excess pretreat not rinsed from garment before dyeing.
• Dye not properly diluted or stirred before bath addition.
• Incompatibility of auxiliaries.

Harshness

• Insufficient size removal
• Use of high quantities of alkali
• Poor softner application

Smell

• Acetic acid,
• Residual chlorine,
• Cationic softners

Back staining

Improper maintenance of

• pH
• Temperature

Blotchy / unlevel dyeing in pigment dyeing

• Improper preparation
• Higher dosage of cationic reactant
• High rate of rise in temperature during Cationization
• Direct contact of steam with garment
• Too low MLR hence uneven build-up of Cationizer

Batch to batch shade reproducibility in Pigment dyeing

• Change in pH during cationization

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