Wash & Drying Process

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Wash & Drying Process

Wash Process

Learning objective

All working with laundry products will be able to recognize and understand the principles of Washing and Drying process and learn about different textiles through selftraining using our LMS

You need to answer 1 out of 1 questions correctly to pass this section.

  • Sinner’s Circle  Multiple needs, many variations but only one PRINCIPLE
  • Sinner’s CircleAll wash programs consist of four elements
    • Temperature 
    • Time 
    • Chemical action 
    • Mechanical action 
  • The Four elements  

  • By altering one or several elements, the others need to be changed in order to achieve the same wash result.For example, if one factor is reduced, the loss must be compensated by increasing one or more other factors

Sinner’s Circle choice question

  • Wash result Time is outside the brackets, as time is the dominating factor 
    • increasing time will affect everything – it will increase the mechanical action, the chemical action and the influence of the temperature. 

  • Mark the correct statements of the components in Sinner´s Circle

Care Label Symbols

    • Maximum washing temperature 60 °C 
    • Normal process
    • Maximum washing temperature 40 °C 
    • Mild process
    • Maximum washing temperature 30 °C 
    • Very mild process
    • Wash by hand
    • Maximum temperature 40 °C
    • Do not wash in Water

Textiles and Fibers

  • Textiles are divided into two main groups: natural fibers and man-made fibers. These are treated differently in the washing and drying process, as each textile has its own special characteristics which must be taken into account. By knowing the textile and its fiber you can make sure that you wash the textile in a correct way which will generate the best wash result.
  • Textile groups Natural fibers and man-made fibers are in turn divided into smaller subcategories, each with its own characteristics and wash specifications. 
  • Natural Fibers/ Plant Fibers Cotton By far the largest of the plant fibres Its range of applications is almost unlimited and it is often used to make garments, towels, bed linen and home textiles in general. Cotton is a high quality material with high wear resistance. It endures powerful processing and high temperatures up to 60-95°C. Cotton also has low elasticity and will easily shrink and wrinkle.
  • Synthetic fibersSynthetic fibers are manufactured from the raw materials petroleum or coal, in a chemical-technical process. There are a great number of synthetic fibers available, and the most common ones are polyester, acrylic and poly-amide fibers. Synthetic materials are strong and its fibers feel cold in cold weather and wet and sticky in hot weather. The advantage of synthetic materials is that they are easy to wash and they dry quickly, as they do not retain water. Synthetic textiles should be washed as fine wash and only short extraction times are recommended.

  • Natural Fibers/Plant Fibers Cotton
  • + Good strength in wet condition+ Resistance to temperature+ Resistance to alkali+ High durability to wash+ Good moisture absorption+ Can be treated to resist shrinking and wrinkling – Soils easily – Low elasticity – Tends to wrinkle and shrink (up to 10%)
  • Synthetic Textiles Polyester, Poly amide, Poly acrylic.
  • + Very good strength+ Resistant to chemicals+ Does not tend to wrinkle easily+ Easy to wash+ Dries quickly – Poor moisture absorption – Sensitive to heat  – Pilling ability increases in mixtures with other fibers – “Plastic” feeling

Which type of fiber has high wear resistance?

  • Mark the right symbol Cotton or Synthetic fiber  
  • Answer 1
  • Answer 2

That’s correct!

  • Good!  Cotton fiber has a higher wash durability than synthetic fibers

Which type of fiber is easy to wash?

  • Mark the right symbol Cotton or Synthetic fiber
  • Answer 1
  • Answer 2

That’s correct!

  • Good! Synthetic fiber is easier to wash than Cotton fibers due the fiber structure.

Which type of fiber has good strength in wet condition?

  • Mark the right symbol Cotton or Synthetic fiber
  • Answer 1
  • Answer 2

That’s correct!

  • Well done! Cotton fibers has better strength in wet condition than Synthetic fibers

What of the following options characterizes synthetic fiber?

  • Mark the correct answers.
  • Resistance to temperature
  • Dries quickly
  • Good moisture absorption
  • Tends to wrinkle and shrink (up to 10%)
  • Resistance to alkali
  • Resistant to chemicals
  • Sensitive to heat

That’s correct!

  • Well done!

Drag and drop the text boxes based on Sinner’s Circle’s elements to match type of fibers.

Reduced filling factor to avoid creases

Lower temperature

Resistance to Alkali

Resistant to chemicals

Long wash cycles will increase the potential for shrinking

Higher temperature

No real limit for the fibers

Long wash cycles does not affect the fibers but increase utility costs

That’s correct!

  • Well done!

Definition of dirt

  • All non-desired particles stuck on textileThe amount of dirt held in 3 kg linen vary between 15 g (very light soiled) to 120 g (heavy soiled).
  • Different types of dirt
    • Deposits, Stain and Bacteria 
  • Dirt substances
      • Water and soluble dirt such as salts and sugar can easily be removed in water – no treatment needed.
      • Fats from animal and vegetable products can for instance be butter and grease.
      • Other dirt substances are solid dirt and pigments such as soot and metal oxides.
      • Protein such as blood , milk and egg need a cold period before heating to prevent the soiled to get fixed. To remove proteins, a detergent with enzymes is necessary.
      • Coloring matters requires a bleaching agent in order to be removed, and lastly, need for a bleaching agent to break the color down or make it invisible.

What type of substance need a cold period before heating to prevent the soils to be fixed?

  • Mark the correct statement.
  • Protein such as milk, blood and egg
  • Coloring matters
  • Fats: animal and vegetable (butter, grease)
  • Water and soluble dirt (salt, sugar)
  • Solid dirt, pigments (soot, metal oxides)

That’s correct!

Surfactants and Detergents

  • Surfactant action1. The dirt particles get stuck on the textile2. The tenside tails attract and surround the dirt particles as well as the textile3. The dirt cannot reattach to the textile due to repulsion 
  • Detergent components include
    • Surfactants, tensides (main ingredient)
    • Alkaline builders
    • Dirt and re deposition agents
    • Bleaching agents
    • Enzymes (break down protein, fat)
    • Anti-corrosion agents (prevents the machine components to corrode)
    • Foam inhibitors
    • Fragrances
  • Detergent overdosing
    • Results in customer wasting money
    • Not in line with the environmental approach of detergent suppliers.
    • Skin irritation
    • Bad finishing results
    • Short linen lifetime
    • Affecting product quality

Water and Temperature

  • Chemical action – WaterThe water acts as a solvent for soluble salts in the soiled fabric and transport medium for dispersed dirt. The ideal water for washing, that causes no discomfort when washing and which achieves the best possible detergent economy, should contain: 
    • Low surface tension
    • Varying degree of hardness depending on geographical locations – ideal hardness is less than 4 – 5˚dH
    • Metal content – Iron less than 0.1 mg/l and Manganese less than 0.05 mg/l
    • Alkalinity: pH 7.0 – 7.5
  • Sinner’s Circle – TemperatureThe surface tension decreases with increased temperature, and the soaking ability increases. Fat is dissolved better at high temperature. The bleaching effect increases at high temperature (except with Chlorine)Temperature selection depends on: Type of textiles, white or colored, soiling degree and hygienic demands.

Filling Factor

  • Optimize the loadingDry linen (in kg) in relation to the volume of the drum (in litre).The loading capacity is always defined as dry weight. The filling factor differs depending on type of textile. Different examples:
    • Cotton 1:9 – full drum
    • Synthetics 1:16 – 75% of drum
    • Delicate 1:20 – half drum

Mechanical Action

  • Sinner’s Circle: Mechanical Action
    • Contributes to removing different particles (soil particles, oil, pigments, etc.)
    • Ensures streaming through the fibers, in order for the tensides and other detergent components to get to the fiber and allow dirt to be removed from the fiber and in the wash bath.
    • Ensures that the pigments and particles are kept in the wash bath and that they do not reattach to the fibers.
    • Ensures that the particles are removed from the water during the rinsing/drain.
  • Drum diameter
    • A large drum diameter will generate better action since the clothes will fall from a higher point.
  • Drum speed and Drum action
    • Normal speed in a wash is approx. 0,7 G. There is a reversing action to prevent tangling. Different textiles require different drum actions.
  • Water level
    • A low water level gives a higher mechanical action since the clothes will have a higher fall. This in turn will generate a better wash result

  • Sample of a Wash Cycle
    • Pre-rinse: Dirty linnen is being flushed with cold water and no detergent. This is used in health care, mop wash etc. 
    • Pre-wash program is used for heavy soiled linen (kitchen, work wear etc), with warm water and detergent. 
    • Main-wash program is applied up to 9 pH-value with hot water and detergent. 
    • Cool-down is used to lower the temperature to 55°C to get permanent press on polyester/cotton. 
    • Rinses follows 2-4 rinses depending on soiling degree. In last rinse warm water softener are added to neutralize the linnen. 
    • Extraction is the start of the drying process which extracts water off the linnen. 

Extraction

  • G-forceG-force is the same as gravity force. The G-force is a combination of diameter and speed. The picture of a carousel below rotates at a certain speed or rounds per minute (rpm). If you sit in the middle of the carousel you don’t feel the rotation as much as if you are placed at the periphery. The same rpm is experienced differently depending on where you are positioned. Two washers with the same rotation per minute but different capacities/drum diameters will have different G-forces. A bigger washer with low rpm can have a higher G-force than a small washer with high rpm. 
  • G-force calculation The G-force is calculated by drum speed  rpm x rpm x drum diameter in meter and divided by 1790
  • Why is G-force important?The higher the G-force the lower the water retention in the textiles. The lower the water retention in the textiles the shorter the drying time and the more money is saved in drying.

From wet to dry

  • Drying processThe drying process starts with water in the textiles being extracted through mechanical force in the washing machine. High G-force in the washing machine gives a lower water retention in the linen resulting in a faster drying in the dryer. In the dryer the drying process starts by arise heat energy, air flow and movement of textile to turn the water into evaporation. 
  • Tumble dryingThe tumble dryer is used to dry linen, or in other words to evaporate the moister away from the linen to obtain a quick and efficient drying process.

VIDEO:

  • Sinner’s Circle As for the performance of washing the Sinner’s Circle also applies to the performance of drying.
  • Filling factor
    • Dry linen (in kg) in relation to drum volume (in liter): Optimal 1:20
    • Cotton, terry towels: e.g. 1:20
    • Synthetics and blended fabrics: e.g. 1:50

After drying

  • Cool down- Provide an anti-creasing effect. – If the tumble dryer stops the moment the drying ends, the garments will still be hot and consequently wrinkle. To avoid wrinkles non-heated air is used to cool down the garments
  • Anti-crease- After cool down, garments will still become creased if left in the tumble dryer. To prevent this, the machine has an anti-crease function to avoid wrinkling. – The drum rotates a few turns at regular intervals for one hour after the drying cycle has stopped.

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