knit dyeing faults and it’s remedies
TRANSCRIPT
WELCOME TO THE PRESENTATION
ONKnit Dyeing Faults and It’s Remedies
Submitted ToRajib Saha
Assistant ProfessorDepartment of Textile Engineering
Name : MAZADUL HASAN SHESHIRID: 2010000400008Batch: 13th Batch (Session 2009-2013)Department: Wet Processing Technology Email: [email protected]: www. Textilelab.blogspot.com Southeast UniversityDepartment of Textile Engineering
PREPARED BY ©right
INTRODUCTION
Dyeing is a process of treating fabrics with dye liquors which contains both dyestuffs and chemicals and fixing the dyes in the fabric subsequently.
In discussing faults which can be attributed to dyer and finisher, it is necessary first to have a general conception of some of the major operations to which goods are subjected after they are received by the finisher of wet processing .
OBJECTIVES To know about the different types of wet processing
faults. To know about the causes of different types of wet
processing faults. To know about the remedies of different types of wet
processing faults. To know about the pre-treatment process of textile
goods. To know about the wet process of textile goods. To know about the finishing process of textile goods. To know about the different types of wet processing
machineries. To know about the job sequence of wet processing
industry.
FLOW CHART OF KNIT DYEINGGrey Fabric
Stitching
Singeing
De-sizing
Scouring and Bleaching
Dyeing
Finishing
Open Fabric
Slitting
Stanter
Compactor
Tube Fabric
Dewatering
Dryer
Compector
Inspection
Packing
Delivery
Some Faultsin
Knit Dyeing Processing
Description of wet processing faults has been found in knit dyeing:
Faults Name Faults Sample
Incomplete Scouring
Causes Remedy
Too Low concentration of scouring chemical
Too Low scouring temperature and time
Ineffective surfactant / wetting agent
Optimum concentration of scouring chemical.
Optimum scouring temperature and
Time. Effective surfactant / wetting
agent.
Faults Name Faults Sample
Low degree of whiteness
Causes Remedy
In adequate concentration of H2O2.
Too low bleaching pH. Too low bleaching time and
temperature.
Optimum concentration of H2O2
Optimum bleaching pH. Optimum time and temperature.
Faults Name Faults Sample
Effect of H2O2 residues
Causes Remedy
H2O2 residues remove not properly
H2O2 killer agent dosing not properly
Not properly H2O2 killer runtime
Running in alkaline condition.
H2O2 residues remove properly H2O2 killer agent dosing properly Properly H2O2 killer runtime H2O2 killer agent runtime must in
acidic condition.
Faults Name Faults Sample
Effect of Hairiness
Causes Remedy
Not properly enzyme dosing High temperature enzyme
Runtime pH not properly controlled Short runtime of enzyme wash When spoil of enzyme activity
Required amount of enzyme dosing Temperature control properly pH controlled must be 4.5- 4.7 Full time of enzyme run Properly enzyme stored in below
25tem.
Faults Name Faults Sample
Barrie
Causes Remedy
It may be caused by variation in the size of the filling yarn
By the differences in tension of either the filling or warp yarn
Variation in drawing ratio in spinning
Temperature variation during fixation process
Exactly size of filling yarn Properly tension of yarn Proper thermo fixation process Selecting dyes and leveling agent
which are not affected by the temperature variations.
Faults Name Faults Sample
Shade bar
Causes Remedy
It may be caused by a change of filling bobbin in the loom or a loom stop and start up.
It is a horizontal band of a different hue running across the fabric.
Properly change of bobbin.
Faults Name Faults Sample
Uneven dyeing
Causes Remedy
Uneven pretreatment (uneven scouring & bleaching).
Improper color dosing Using dyes of high fixation
property. Uneven heat-setting in case of
synthetic fibers. Lack of control on dyeing m/c.
By ensuring even pretreatment By ensuring even heat-setting in case of
synthetic fibers. Proper dosing of dyes and chemicals. Proper controlling of dyeing m/c.
Faults Name Faults Sample
Line mark
Causes Remedy
Long time store in the floor Dyeing process not properly Extra tension on the fabric
Properly stored in the after dyeing Exactly dyeing process control Tension less fabric run in the dye bath
Faults Name Faults Sample
Batch to Batch
Shade variation
Causes Remedy
Fluctuation of Temperature. Improper dosing time of dyes
and chemicals. Batch to batch weight variation
of dyes and chemicals. Dyes lot variation.
Use standard dyes and chemicals. Maintain the same liquor ratio. Follow the standard pretreatment
procedure. Maintain the same dyeing cycle. Identical dyeing procedure should be
followed for the same depth of the shade.
Faults Name Faults Sample
Dye spot
Causes Remedy
Improper Dissolving of dye particle in bath.
Improper Dissolving of caustic soda particle in bath.
By proper dissolving of dyes and chemicals.
By passing the dissolved dyestuff through a fine stainless steel mesh strainer, so that the large un-dissolved particles are removed.
Causes Remedy
Poor opening of the fabric rope.
Shock cooling of synthetic material
If pump pressure and reel speed is not equal.
Due to high speed m/c running.
Maintaining proper reel speed and pumps speed.
Lower rate rising and cooling the temperature.
Reducing the m/c load. Higher liquor ratio.
Faults Name Faults Sample
Crease mark
Faults Name Faults Sample
Roll to roll variation or
meter to meter variation
Causes Remedy
Poor migration property of dyes.
Improper dyes solubility. Hardness of water. Faulty m/c speed, etc.
Use standard dyes and chemicals. Proper m/c speed. Use of soft water.
Faults Name Faults Sample
Thick –thin yarn
Causes Remedy
If thick/thin yarn is used for making a fabric.
Used of immature fiber. Used of short staple length of
fiber.
After dyeing this type of problem cannot be removed but can be avoided by not mixing the thick/thin yarn in a single fabric.
Faults Name Faults Sample
Off shade
Causes Remedy
It refers to color that does not exactly match the standard or the prepared sample.
This may be due to faulty dyed foundation or application or may be due to variation in dye lot.
Properly select of dye. Correctly fabric lot selection.
Faults Name Faults Sample
Insufficient hydrophilic
Causes Remedy
Insufficient removal of grease, wax and sizing film which gives hydrophobic characteristics to the fabric. When a fabric with un uniform hydrophilic is dyed, areas with different lower / hydrophilic results in a lighter shade are obtained due to the lack of absorption of the dye liquor.
To avoid this a thorough pre-treatment is a must,
Wetting agent can be used in dyeing liquor.
Faults Name Faults Sample
Bowing
Causes Remedy
Woven filling yarns lie in an arc across fabric width; in knits the course lines lay an arc across width of goods.
Establish standards of acceptance .Critical on stripes or patterns not as critical on solid color fabrics.
Uniform sewing is required. Equal width fabric is required. Proper tension fabric passes in
compactor.
Faults Name Faults Sample
Compacting crease
Causes Remedy
Excessive apply on Teflon pressure.
Less tension roller. Uneven temperature of two
cylinders.
Minimum required of Teflon pressure. Exact setting of tension roller. Exact setting of temperature in cylinder.
Faults Name Faults Sample
Water spot
Causes Remedy
Fixation with a few drop of water on specific area of dyed fabric
Proper fixation
Faults Name Faults Sample
Poor washing fastness
Causes Remedy
Inadequate washing of hydrolyzed dye.
Inadequate removal of loosely retained dye.
Inherent low fastness properties of the dye.
Optimum washing off. Use of cationic fixing agent or other
fastness improving after treatment.
Faults Name Faults Sample
Oil & Grease Spot
Causes Remedy
During dyeing and finishing process sometimes oil and grease may fall on fabric which may cause oil and grease spot on the dyed fabric.
Due to careless transport of dyed or finished fabric.
Must be careful about oil and grease during dyeing and finishing process.
Must be careful about the transportation of dyed or finished fabric.
With immediate application of spot –lifter.
Faults Name Faults Sample
Pilling effect
Causes Remedy
Pilling is a common fabric occurring on knitted and woven fabrics.
In producing a yarn fibers tightly twisting produce a serviceable yarn. When short stable fibers are mixed into the yarn the result is a yarn that will not together. The short staple fibers will separate from the yarn and curl up in a ball,- forming what is referred to as a pill.
Pilling is accentuated by the friction of normal wear, washing and routine dry cleaning.
Exactly maintain of enzyme wash. Evenly mixing of short staple fibers. Properly twisted of yarn.
CONCLUSION
Two months industrial training at Alim knit tex (Mondol Group) Ltd, Metro Knit and Dying Mills Ltd, Square Knit Fabrics Ltd. were a part of B.Sc. in Textile Engineering course. During the training period the whole 60 days were segmented and scheduled to a systematic routine. There was different faults operation in textile wet processing.
It should be mentioned that Alim knit tex (Mondol Group) Ltd, Metro Knit and Dying Mills Ltd, Square Knit Fabrics Ltd. are 100% export oriented knit dyeing industry .To produce a quality product above all export quality it could be desirable that the process should be high standard.
Here we have some limitations in our training period, and two months are not enough time to complete the knowledge about the textile terms.