Defects in Dyeing with Reactive DyesDefect: Colors are not fast to washing, Abrasion;Staining in the fabric when transporting from place to the other, water marks on the fabricRemedy : Wash the fabric with soap and soda ash at right temperature. Adding sequestering agent will yield good results. Treating with Ammonia will also give good results.Defects in the fabric due to Printing- Need to take out full colorRemedy: Treat the dyed fabric with Sodium Hydrosuphite with 5-10 gm Sodium Hydrosulphite at 75 deg C for 30-45 minutes. Add 5-7 gms Caustic Soda for even removal of colors. The color becomes light yellow or brown after removal. Wash it thoroughly with soap.The color can also be removed by solution of Sodium Hypochlorite. Treat the fabric with a sodium hypochlorite solution ( 3-5 gms Chlorine) for 20-30 minutes. Keep the pH between 9-10. The fabric is treated with Acetic acid after removal of color to remove chlorine and to neutralise the fabric.The fabric can be redyed after removal of colorDefect: Bleeding in colors during washing, abrasionRemedy: Boil the fabric with caustic, Treat the fabric with Hydrogen Peroxide ( 5-10 gpl, 60-70 deg C) to make the color fast.Defect: The fabric has been dyed in darker shade, uneven dyeingRemedy: To take out color from the fabric treat it with caustic for 45-60 min at 70 deg C. Thereafter treat the fabric with 10-20 gpl Acetic Acid for 40-60 min at 80-85 deg C.Defect: Uneven dyeing, marks of water, marks of colorsRemedy: Wash the fabric in soap and redye in a darker shadeDefect : The fabric has become stiff and rough after dyeingRemedy: Finish after adding right softnerDefect: Color staining of fabric, uneven dyeingRemedy: Redye the fabric in darker shade.Defect: Color staining in fabrics of darker shade, uneven undyeingRemedy: Dye the fabric in Sulphur blackCaution: Please treat a small length fabric to check the effectiveness and any harmful effects before commencing a full treatment.About these ads

Common Causes of Dyeing Defects:

It is important that the general precautions should be followed while dyeing a textile material. It is always helpful

to keep a record of all the conditions (including temperature, time, conc of color, chemicals, material to liquor

ratio) in order to get an even shade in each batch. In general the following are the common causes of dyeing

defects across all the categories of dyes:

1. The material is not well prepared for dyeing and printing

a. Material having dead fibres or other defective fibres

b. Left over of Chemicals after bleaching etc.

c. Material not properly desized

d. Material not properly mercerised.

e. Absorbancy of the fabric not proper

f. Sticking of insoluble material on the fibres

g. Impurities are not removed properly

h. Uneven heat treatment.

2.Water Quality not Proper

a. More Hardness of water

b. Water has metal ions such as iron.

c. pH of water not proper

d. Water having more chlorine

3. Due to Shortcomings in making Dyeing Solution

a. Improper weight ratio of colors, material and chemicals.

b. Improper material to water ratio

3. Improper filtering of concentrated colors.

4. Due to Shortcomings in the dye machinery

a. Coming out of Dye liquor during dyeing

b. Defective instruments controlling temperature, pressure speed etc.

• fJIGGER DYEING

• thE Fabric is wound around one of the rollers; during dyeing the fabric is passed through the dye bath and rewind on to the second roller.

• When all First the fabric is passed through the dye bath the direction of movement is reversed, this would be repeated until the dyeing is completed. During dyeing tension is imparted in length of the fabric.

• Suitable for delicate fabrics & light wt. Fabric.

• Low liquors ratios (1:2 to 1:6) the consumption of chemicals and energy is low.

• Knitted and stretch woven fabrics cannot be used

• Machine Details

• Machine make: Swastik (India)

• Number of operator: 1 operator per 2 machines

• Total number of machines: 13

• Production: 20,000 m/ 13 machines/ day

• Speed of the machine: 60 m/min

• Roller pressure: 70 – 75 Kg/cm²

• Maximum Temperature: 80º C

• SCM Textile Processing Mills in Erode.

PROCESS FLOW

• SAMPLING (COMPUTER ART DESIGN)

• STRIKE OFF FOR SAMPLING (SMALL SCREEN DEVELOPMENT)

• PARTY SAMPLE APPROVAL

• BLD (BRIGHT LIGHT DUPLICATE)

• ROTARY SCREEN EXPOSING

• PRINTING

SCREEN PRINTING

• The respective screens are mounted on the roROTARY tary heads

• Selected squeegees are inserted and connected to the respective colour pumps

• The fabric to be printed is fed to the blanket and gets printed by the respective screens in continuous manner

• The printed fabric is conveyed through dryer and plaited

Machine details:

• Machine make: Stomac

• Machine width: 70 inch

• Numbers of colours possible: 12

• Numbers of operators: 1 operator and 4 assistants per machine

• Printing speed: up to 80 meters/minute

PRINTING

• Pigment printing is one of the simplest direct styles, which is applicable to all class fibres

• Since the pigments are insoluble colouring PIGMENT matters, they are physically applied by means of binders.

DISCHARGE PRINTING

• Discharge prints are fabrics that are dyed a solid colour prior to printing.

• The design is applied by screen or roller with a chemical a reducing agent which removes the colour of the originally dyed fabric.

Cotton Dyeing:

• Temperature: 60-80 degrees

• Pressure: atmospheric pressure

• pH: 10.8 – 11.4

• Dye: Reactive dyes

• Time: 45-75 min

Polyester Dyeing:

• Temperature: 130 degrees

• Pressure: 2kg/cm2

• pH: 4 - 5

• Dye: disperse dye

• Time: 2 hours

• Bleaching

• Checking pH (process before pH =5.5-6)

• Dyeing (pH = 7-9)

• Shade checking

• Soaping (95 degree Celsius for 15-30 minutes)

• pH stabilization + finishing

Machine Details

Machine make: THIES

Number of operator: 1operator and 1 assistant per machine

Total number of machines: 7

Capacity: 1080 kg/batch