Identification of Fibres, Stains and their treatment

Removing stains is a major challenge for hotel laundries and has to be done in a scientific manner

Nearly all fibres can be identified by appropriate tests. However, it is not possible for the launderer to apply all the methods. The principal methods of classifying fibres according to their raw materials are listed below. The exact scientific testing of textile materials is usually a matter for laboratories with their appropriate technical
equipments.

Test by burn

Cellulose fibres: Light lively flame burns quickly with glow point, cotton, flax, rayon, pungent smell of burnt paper, fly-ash.
White of egg fibres: Burns reluctantly, flame inclined to go out, the small fibre crinkles under the heat and forms small lumps. The cooled residue is lumpy and can be rubbed between the fingers to a sandy mass.
Mineral fibres (asbestoses): Do not burn
Acetates: Burns similar to cellulose but more slowly, with acid smell and crusty residue.
Polyamide: Nylon, perlon etc: Burns very reluctantly, but melts and drips; ball shaped residue which is firmly connected with fibre.
Polyester: Burns reluctantly, melts and drips a somewhat flickering flame with little smoke. Residue like polyamide.

Stain identification

Three criteria assist in identifying the most commonly known types of stains and classify them accordingly.

• Type of edge
• Feel
• Colour.

Type of edge

We distinguish between strong, clearly defined edges of the stains and less clearly defined stains area, which merge with the fabric. The type of edge is typical in case of the following stains.

The following stains have sharp and dark edges:

• Blood stains
• Starch stains
• White of egg stains
• Varnish
• Oil paints
• Glue.

All stains cannot be recognised by the appearance of the edge.

Feel

Here we distinguish between hard and soft stains. Hard stains are caused by:

• Varnish
• oil paints
• glues.

Stains, which are less hard but can be described as stiff, are stains containing albumin.

Further, if a stain contains albumin, when rubbing it against a hard object (finger nails) the stain pulverises and thereby becomes lighter, sometimes vanishing altogether.

Colour

Yellow/brown stains: Rust, coffee tea tannin tobacco juice, banana, sugar, suntan emulsion, urine, perfume, burns and scorches, blood.
Blue stains: Watercolour, ink, ballpoint pen ink, dyes.
Green stains: Grass, water colours, ink, ballpoint ink, dyes.
Red stains: Watercolour, ink, lipsticks, nail varnish, hair dyes.

Stain removal tips

Removing stains from textiles is one of the most difficult tasks of the laundry industry. We give below some tips of how to remove the most common types of stains.

Stain removing procedure

Application of spotting chemicals
Spotting chemicals should be applied by means of a small plastic bottle with a long necked nozzle. Every endeavour should be made to keep the area to be spotted as confined as possible.

Effect of steam
Steam from a steam gun server to heat the chemicals in order to increase their effectiveness. The steam gun must be always be handled with great care as the high steam pressure can damage the fabric or effect the surface properties, dyes, and thermoplastic fibre can be irretrievably altered. A distance of three to four inches has to be maintained between fabric surface and steam gun nozzle. An exception can be granted for very hard surface.

Rinsing of stained surface after stain removing
Rinsing off the stain treated spot is very essential, making stain invisible is not sufficient, it can reappear, while doing the pressing or ironing, this spot should be rinsed thoroughly several times so that all the chemicals are removed from the surface.

Formation of spotting rings
Always apply the spotting chemical on the outer edge of the stained area and treat the stain. Then rinse the spotted surface several times by forming a ring. Work the edge towards the centre when drying with compressed air, i.e begin with blowing at the outer zone and gradually shifting liquid towards the centre.