Wool fabrics are scoured, bleached &
chlorinated. The fabric is first washed in rope form in hot water for 30 mins.
Then soaping is done with a neutral soap at 60°C, washed &
hydroextracted.
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| Wool Treatment |
It is then passed in open width through a
solution containing 3% peroxide made alkali with NH3 because NaOH is not used
for wool. Batched & rotate for 24 hours. It is then washed & passed
through a solution of sodium bisulphite and batched for 3-4 hours. Then washed
and neutralized with dilute H2SO4 solution &washed thoroughly. Then the
fabric is chlorinated with bleaching powder solution for 1 hour followed by
wasing. The chlorine increases the affinity of the woollen fabric.
Wool blends pre-treatment process
Wool blends pre-treatment process
PET is a
synthetic fiber and Wool is a Natural fiber. Textile pretreatment is the
series of cleaning operations. All impurities which causes adverse effect
during dyeing and printing is removed in pretreatment process. Fiber
has to be treated in different ways to remove the unwanted contents from it and
make it into suitable Prepared for Dyeing/Ready For Dyeing.
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| Pretreatment Machine |
The pre – treatments given to PET – wool blends
are as follows
Singeing
Singeing is carried out on gas singeing machine
to achieve maximum efficiency. The singed fabric is given light scouring
treatment to remove degraded fibre and odour.
Pre-setting
PET-wool blends may be present before scouring
to reduce distortion, rope marks and shrinkage. In dry blowing presetting, the
fabric is wound on a perforated roller and steamed for 10 minutes at pressure 1
– 3 kg/cm2. In crabbing pre-setting method, the fabric is passed through water
in first bowl at 80 -90°C and the through the second bowl at boiling
temperature. A period of 3 – 5 minutes in each bowl followed by similar period
in steaming if necessary gives satisfactory results.
Scouring
Scouring is carried out with a solution of
sodium carbonate at 2 – 2.25 % and soap on detergent 3 – 4 % at 40 °C,
which is followed by washing and second treatment with soap at 30°C for 40
minutes. The goods are then thoroughly washed.
Removal of heavy stains
The stains are removed by spotting agents
applied locally, followed by vigorous washing before solvent evaporates. Cold
organic solvents such as trichloroethylene, trichloroeathane or white spirit
are used as spotting agent.
Heat setting
PET – wool blend is heated at 170°C for 25 – 30
s allowing 1 – 5 % relaxation. Shrinkage in observed in both warp and weft
direction. Heat settling is carried out on a stenter fitted with an overfeed
attachment and tapering chains.
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