• item type — finishing requirements • colour — loose dyes
• soiling type — oily or protein?
• soiling level — heavy, medium or light?
• production requirements — priority and sequencing? • disinfection — thermal or chemical?
• special fabric finishes — fire retardant • rewash — for what reason?
Fibre type
There are hundreds of different fibre types available to textile manufacturers, but only a few of these are typically found in commercial laundries.
Fibres can be divided into two groups — natural and man-made. The most common natural fabrics are made from vegetable matter (eg cotton) and from animal byproducts (eg wool). The most common man-made fibre is polyester.
Cottonis a very popular fabric with linen hire and flatwork rental companies because it can be finished in a commercial laundry to a high standard and will withstand a well- balanced industrial wash process well. It is very resistant to alkalis and the way the cotton fibres swell in an alkali wash solution helps to loosen dirt and make it easier to remove. Also, because of its high water absorption capacity, cotton is a very ‘comfortable’fabric next to the skin, and is therefore used extensively for hotel bed linen and towelling. Cotton is susceptible to chemical attack from acids and from sodium hypochlorite. Great care should be taken when bleaching cotton with sodium hypochlorite, as low
concentrations cause some damage and high concentrations make the cotton fibres extremely weak. Even low concentrations will cause accelerated rotting in the hot wash. Cotton can also be damaged by micro-organisms that find their way into the hollow fibres and multiply in damp and warm conditions to form mildew.
Wooland other fabrics made from animal derivatives are rarely seen in commercial laundries these days. Despite having many qualities, they do not respond well to alkali,
wash temperature or mechanical action in the washing machine.
The classification of domestic and personal soiled fabric items involves a greater
awareness of fabric types. You must be aware of what each item is made of and how this fabric will respond to the wash process your classification will give it.
The added difficulty with domestic and personal items is that they are often made up of mixed fibres and are not of a standard quality.
You will be expected to use your skill gained from training and experience to assess items for their washability as you count and mark them.
Polyesterhas taken over from natural fibres as the most common fibre in use today. Polyester was first patented in 1941, and since then there have been many types developed from different base chemicals.
Polyesters are very hard wearing and can withstand misuse. But they can be cold next to the skin and are not suitable for all applications. For example, sparks from welding would make a polyester overall melt and polyester sheets are uncomfortable to lie on for long periods. They are resistant to acids and all types of bleaches, but can be damaged by very strong alkalis.
Polyester, however, has several major drawbacks. It attracts oily and fatty soiling, tends to generate static electricity when agitated and forms creases that detract from the laundered finish.
A polyester fibre is a type of plastic, and when it is heated in the laundry process it can be bent, which causes a crease in the fabric. There are two main reasons for these creases: • Thermal ‘shock’creasing is caused when the hot pliable polyester fibres are cooled
down quickly, setting the fibres in a bent and twisted state. To overcome this problem the wash and drying process has to include a cool down period where the
temperature is slowly reduced to about 52 °C slowly (at approx 4 °C per minute). • Pressure creasing can be caused by the weight of the work during the hot wash in a
large capacity machine and by over-extraction or extraction when items are still hot. Any polyester items left in barrows or cages after washing will develop creasing. To try to gain the benefits of both types of fibres, many items are manufactured from a mixture of cotton and polyester. It should be noted that the cotton in these polycotton items would be damaged if hypochlorite bleach were used.
G8CC 22 —Dry Cleaning Operations Level 2
3.28
How would you prevent polyester garments from creasing during processing in the laundry?
Item type
Classification by item type is required due to different finishing techniques later in the laundry process.
A lightly soiled white cotton pillowcase and towel will be classified separately. The pillowcase will only require conditioning in the tumble dryer and will then be ironed. The towel will be fully dried and folded. It is usually more efficient to separate different item types before washing rather than after.
Colour
White and coloured items should not be washed together. Dye transfer will occur at any temperature. At best, whites will become dingy and at worst they will take up a pale colour. Colours should also be classified carefully, with pastel shades kept separate from dark colours. Even if the dyes are relatively stable there can be a problem with coloured lint contaminating lighter coloured work.
Imagine that you are holding a soiled chef’s jacket with red trimming. What would you have to consider before classification?
Cotton pillowcases are probably washed in their thousands in your laundry,but if you receive a very old linen pillowcase with delicate lace trim and coloured
embroidery in a domestic parcel,it would probably be ruined if classified as a standard pillowcase.
This example would probably not even carry a care label to help you decide the most suitable process classification.
What would you do with this pillowcase?