Friday, 1 March 2013

Linen wrinkling


Linen has poor elasticity and does not spring back readily, explaining why it wrinkles so easily.[1]
The molecules of water bonds with cellulose moleculs easily and this creates the wrinkle problems in linen. A splash of water on an untreated linen fabric and the water molecules insinuate into the polymer chains, destabilizing the existing bond. When the fabric starts to dry, new bonds starts to form. The rearranged chains leave the fabric with wrinkles or creases depending if the fabric was folded as it dired. Added heat accelerates the process of fast shrinking.  Meanwhile while heat and water causes wrinkles, they are also working in the reverse efect of removing wrinkles. It is impossible to get rid of the wrinkles from a dry linen fabric, neither its possible to remove the wrinkles with only hot iron.  Is the wetting is included in the ironing process the wrinkles are easily removed by rearanging the wrinkled bond. The explanation to this si that adding water swells the fabric fibers, breaking the hydrogen bonds that reated the fabrics wrinkles furthermore heat again speeds up the proess. Due to the fact that linen absorbs wter wery easily and it is not an elastic type of fiber it tends to form a sharp wrikles as it dries, furthermore with repeated wrinkling linen fibers war and break along the fold.[2]
To assess the wrinkle for the linen an ISO 15487 test should be applied. And the process of the wrinkle test. The test specimen is a piece of fabric in this case a piece of linen fabroc. Appropriate light and evaluation area and American association of textile chemist and colorists standard smoothness appearance replicas prepared for evaluating appearance. The procedure is to wash and dry one out of three specimen four to five times. And during the first four washing and drying cycles the specimen should be ironed to remove wrinkles but the procedure shouldn’t be done after the fifth washing and drying. The specimen should be hanged for 4 hours straightening and smoothing facings and seams. After the four hour period the specimen should be compared to the replicas according to the ISO 15487 test regulations.

In the picture below you can see the replica that is used to assess the wrinkle level and description.
[1] ISO 15487 textiles method for assesing appearance of apparel and other textile end products after domestic washing and drying.

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