Transversal view Longitudinal view
The most common quality silk is the mulberry silk, so-called “Bombix mori” after the name of the silkworm, the larva or caterpillar of a silk moth, from the Lepidopteran family that it is feeding itself with the mulberry leaves. It is the most common silk. There are also some other types of silk derived from the larva of various wild species: the “Tussah” silk.
Summarizing, the silk garments have a different behaviour to:
Print colour discharge on silk garment
Colour resistance – Generally, the colour fastness to water and sweat treatments is low, leading to possible discharges especially for the dark colours. For dark solid-coloured garments, it is necessary to avoid washing them together with light-coloured garments, while for the contrasting-colour garments, it is essential to carry out some preliminary tests of colour fastness (passing the iron over a white cotton fabric tester, soaked in a solution of water and sweat for checking possible colour discharges).
Rubbing and folding should be avoided, as the fibres tend to fray, ruining the garment; for this reason, on silk garments can often show up some lighter coloured areas, caused by a superficial colour loss, due to longitudinal splitting of the fibres.
Colour fading due to longitudinal fibres splitting
Resistance to chemicals – the hypochlorite (bleach) should not be used at all for bleaching, it is recommended instead, the use of the hydrogen peroxide, which does not damage the fibre.
Chemical attack failures
Ironing – In ironing the silk, you should not exceed 100-150°C. Watch out for the steam as the condensation droplets can cause stains. Do not over-dry, the silk should be ironed damp, otherwise it will be over-loaded with electrostatic charge.
The fabric sticks to the legs Condensation droplets
by electrostatic charge
Washing – It is not recommended the water-washing, as it can cause colour discharges, degradation and a change in the appearance of the fabric surface, which it looks less smooth and more wrinkled (fibres are absorbing water and change their trim) and additionally it loses its brightness. It can be safely dry-cleaned.
Colour discharge on the Wrinkled surface appearance
originally white fabric
tester
When water-washing, it is recommended to wash by hand, not exceeding 40 °C (104 °F), with neutral or slightly alkaline detergents and only for short time. It is necessary a frequent washing as sweat traces will cause both colour degradation and deterioration of the mechanical properties. It must be dried flat, in the shade. Silk should be stored away from light and humidity, otherwise it will get yellow easily.
Color fading from sweat Tearing on the curtain due to light effect
The most indicated care symbols for the silk garments are:
The silk has a low resistance to snagging (pulled threads); pay a special attention at the pick-up time, to the presence of possible pulled threads. For the delicate garments, it is recommended to place the garment in a bag, to avoid the rubbing against any non-smooth surfaces.
Snagging “pulled threads” Example of fraying
Silk fabrics will easily “fray”, the warp threads are sliding over the weft threads; pay a special attention at the pick-up time, to the presence of possible fraying. Avoid the use of softeners that reduce the resistance to fraying. •
Textile Research and Analysis Laboratory
Via Vasco de Gama 2 – 41012 Carpi (MO)
T. 059 645279
lart@lartessile.it – www.lartessile.it
By ING. VITTORIO CIANCI
Director LART – Textile Research and Analysis Laboratory
DETERGO Magazine # May 2023
