Shrinkage

6 July 2015



Garments will usually undergo some kind of size change in drycleaning, most commonly shrinkage. Richard Neale of the Drycleaning Technology explains


Only a few items will stay the same size in drycleaning - mostly those from glass fibre. One or two may get bigger, but shrinkage is most likely and a common occurrence, despite the disbelief of the owner and disclaimers from retailers.

British and International Standards recognise dimensional change in cleaning and provide methods for manufacturers to check the shrinkage potential of new ranges before they reach the shops (BS EN 3175 parts 1 to 4, with part 4 specific to wetcleaning). Unfortunately, very few makers use the Standard to check the expected shrinkage and few, if any, retailers warn customers of this at point of sale. A snug fitting, fully fashioned garment may fit perfectly in the shop but become just slightly too tight after cleaning. The cleaner then has to explain why garments often shrink and what, if anything, can be done.

Most rolls or bales of fabric will have had a slight stretch set in during manufacture and for some delicate or very elastic fabrics, this set can be considerable. The stretch survives garment make-up and normal wear but it is released in the first few drycleans. British Standards advise that it might take up to five cleans to bring out all of the changes. This is called relaxation shrinkage. It affects all fabrics, probably due to lubrication of the cellulose chains in the cotton (or the polymer chains in other fibres) at the molecular level, which releases the set and produces the loss in size.

The other types of shrinkage in cleaning are solvent shrinkage, felting shrinkage and thermal shrinkage. The garment maker is always responsible for relaxation shrinkage (the cleaner cannot influence this), but the responsibility for the other types depends on the accuracy of the labels and how well the cleaner interpreted these.

Silk/mohair sweater suffers felting
Fault:
This luxurious sweater shrank noticeably and the fabric became thick and matted, so it lost elasticity and its soft handle
Cause: Drycleaning involves substantial mechanical action but most items will withstand this provided the moisture in the system is well-controlled. Felting shrinkage as severe a as this will only occur if the solvent contains water or the garment was damp when it went into the machine.
Responsibility: The cleaner took the blame here. Pre-drying silk and mohair by airing in a warm dry place is part of the cleaner's craft skill. The owner would not have realised that handing in a damp garment could affect the result.
Rectification: None.

Silk wedding dress shrinks and cracks
Fault:
The owner of this wedding dress noticed that after it had been cleaned, the outer silk layer had a fine "basket weave" effect and extensive but very fine "crack creasing". Neither fault could be pressed out.
Cause: The cleaner routinely washed all wedding dresses because washing had been found to be the most effective way of removing food and drink spills, champagne spray and hemline dirt. Many dresses are polyester which will usually wash well but washing this silk dress has caused the crack creasing ant basket weave effect.
Responsibility: The dress was labelled only for drycleaning so the cleaner took the responsibility here.
Rectification: None. For the future, the cleaner is checking the fibre content of all wedding dresses and only washing those that do not contain any silk or acetate.

Elastane snaps and sprouts
Fault:
This bi-stretch skirt was labelled for perc cleaning on a delicate cycle and also had the one-dot iron symbol. When it came out of the drycleaning machine, ecru-coloured elastic fibres were sprouting all over the outer surface.
Cause: Elastane is inserted under high extension at the weaving stage give the fabric a bi-stretch function. It is often stretched by up to 300% at this stage, but if the maximum permissible extension is exceeded or if the elastane is not of good quality, it will tighten and snap when it then it comes into contact with perc and the broken ends will work out of the fabric during tumble drying.
Responsibility: The manufacturer should take responsibility. The elastane has been inserted under slightly too high a tension, so inevitably it tightens and snaps with the solvent action. The manufacturer needs to make allowances for the effect of solvent action on elastane during cloth production.
Rectification: None.

Differential shrinkage ruins wedding dress
Fault:
This expensive wedding dress had a top layer of fine knitted silk netting. This layer was made from a full circle of fabric, which was cut into a doughnut shape. The layer was then gathered and secured at the waist and allowed to fall naturally into loose folds with a uniform hemline. After cleaning, the lower hemline was no longer uniform but rose and fell smoothly around the circumference, revealing the underskirts and making the garment impossible to finish.
Cause: If the outer layer is cut from a flat doughnut-shaped layer, then, any difference in the relaxation in the warp and weft directions, will produce varying shrinkage around the circumference. As a result the hemline now rises and falls unevenly around the garment.
Responsibility: The wedding dress was labelled for spot cleaning. As it was not particularly soiled, this would probably have worked quite well and the fault would not have occurred. The cleaner should be taking the blame for this very unusual fault.
Rectification: The fault cannot be rectified. Completely replacing the outer layer would be the only solution.

Interlining delamination problems return
Fault
: DTC is now seeing several suit jackets, such as this one, that have a pattern of horizontal ridges on the front after being cleaned.
Cause: Opening the jacket at the lining seam revealed that the main interlining, used to support the fronts, was well secured to the reverse of the outer fabric. It was also found to be flat, even in the area of the outer ridges. These symptoms indicate that the interlining substrate has suffered a greater degree of relaxation shrinkage than the outer fabric and the excess outer fabric has produced the ridges. Research published by a reputable suit maker in the 1990s indicated that the relaxation potentials of the layers in a laminate should be within 2% of each other to avoid this fault. If the difference in shrinkage is more than 2%, the bond between layers will rupture, with the result shown.
Responsibility: The maker should take responsibility here.
Rectification: None.

Zip becomes wavy in cleaning
Fault:
This cotton jacket cleaned up very well but the owner was disappointed that the zip was now wavy rather than flat as before.
Cause: The flat support fabric used for the zip was not properly relaxed before it was used in zip manufacture. The solvent's action has lubricated the zip fabric, releasing the slight stretch set in and causing the waviness.
Responsibility: The manufacturer should be taking the responsibility for this fault. It is possible to purchase well-made zips that do not give this problem.
Rectification: The zip fabric should be lubricated with a little bottom-steam and then stretched very firmly along its length. Vacuum is then applied for double the normal time to cool, dry and set the material. When tension is finally released it will be found that the waviness has been removed. It is essential to use strong vacuum and to apply it for sufficient time to solve this problem, which is now becoming increasingly common

Jacket wrongly labelled for perc cleaning
Fault:
This padded jacket with fine cotton outer was cleaned in perc in accordance with the label but afterwards looked "crazed" with ridges like miniature mountain ranges along the lines of crazing.
Cause: The cotton outer has a back-coating of plasticised polyurethane. The action of the perc has temporarily destroyed the adhesion of the coating and it has lifted during the solvent wash. Then during the tumble dry it has partially reattached in the wrong place. The result is the ridged and crazed appearance seen here.
Responsibility: The maker should be taking responsibility here because the labelling should be suitable for all parts of the garment, and this was incorrectly labelled for cleaning in perc.
Rectification: None.

SOLVENT SHRINKAGE
ZIP RELAXATION
DIFFERENTIAL SHRINKAGE
FELTING
SOLVENT TIGHTENING
SILK CRACKING
INTERLINING DELAMINATION


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