Many launderers would like to know the secret of minimising progressive rotting of cotton fibres and the destructive hydrolysis of polyester and nylon fibres, so that they can achieve over 200 wash and use cycles for every textile classification.
This is a great selling point for contract customers sending in their own goods and a vital contributor to profit in a textile rental business. This month we look at the minimisation of chemical damage in a modern wash process, without detracting from quality, freshness and stain removal.
Common causes of chemical damage
- An effective (low cost) main wash often relies on alkali chemistry in the detergent, to saponify fats such as skin sebum on hotel sheets and pillowcases. Alkali does not cause much damage to cotton (unless used to excess) but it can rot nylon and polyester by a degradation process, which chemists call ‘alkaline hydrolysis’. The more concentrated the alkali and the higher the main wash temperature, the greater the degree of damage and the shorter the textile life. Incomplete rinsing often makes matters even worse (because of damage and discoloration during drying or ironing as any unrinsed alkali is concentrated up when the moisture evaporates).
- Many de-staining systems tend to rely on sodium hypochlorite solution, which is superb at stain removal, but it always causes some chemical damage to cotton, linen and viscose fibres in every wash. It is the cumulative effect of this which is the prime factor in determining textile life in a great many organisations. This damage can spiral out of control if the dosage and/or the bleaching temperature are not correctly controlled and excessive damage from these systems features in a significant percentage of users. This is a particular problem if protein stains are not correctly softened in the pre-wash, because the necessary increase in sodium hypochlorite dosage to remove set protein stains reduces textile life even more.
- Sodium hypochlorite can also cause additional indelible staining if it is used on healthcare work, or on hotel or spa work which has been used with skin treatments which contain ‘chlorhexidine’ (a popular and effective disinfectant, used in Savlon for example).
- Over-washing occurs when still-stained items are put back into the normal wash repeatedly. They go round twenty or thirty times, become grey or ragged and are then scrapped as worn out and unusable.
- Floor marks are much more difficult to remove than normal soiling and staining and most wash processes are not geared to tarmac stains, muddy boot-prints or air conditioner drips, for example. Towels which are used to wedge doors open or mop up toilet floors will rarely come properly clean, however good the wash.
- Machine marking from worn rubber seals and oily mark-off can be exceptionally difficult (and often impossible) to remove.
How to address the challenge
- The latest built detergent systems have shifted the reliance on strong alkali alone and now incorporate chemicals that emulsify oils, fats and greases, along with enzymes which ‘digest’ protein stains. This reduces the risk of damage to the polyester fibres in polycotton and cotton rich and helps to make the 200-cycle life achievable. It also brings with it a useful reduction in damage to calender clothing, which is generally made from polyester (occasionally with an aramid top layer). Carryover of alkali from the wash can attack both of these progressively to cause ‘map of the world’ degradation, going into widespread holes over the outer layer of calender or press clothing. Avoiding this also demands effective rinsing or precise neutralisation in the final rinse, aided by efficient moisture extraction.
- These modern detergents have resulted in much reduced consumption of sodium hypochlorite in the UK on and its virtual elimination in continental Europe. By taking out the difficult stains (those which demanded over-dosing of hypochlorite), the present generation of premium detergents call only for a tiny dosage of bleach for vegetable dye stains from tea, blackcurrant and red wine (for example).
- The gulf between the market leaders in linen life, who achieve over 200 wash-and-use cycles per item, and the rest of the sector is still wide. This might be because the best performers now control their pre-wash temperatures to just below 40C, so that protein stains are softened before their total (and very easy) removal in a well-designed main wash.
- Where significant beaching is still required (for eliminating very heavy vegetable dye stains, for example), there has been a move to hydrogen peroxide or sodium percarbonate. This is a much safer bleaching agent than hypochlorite, because it does not cause accelerated rotting of cotton in the hot wash and it is not very effective on set proteins (so there is much less temptation to overdose).
- Floor marks need to be eliminated swiftly by regular training and reminders , firstly in the laundry, then with delivery staff and finally on client premises. There is no sure chemical or machine solution – it is the human factor which must be sensitively and persistently addressed, often repeatedly!
- Textiles which are still stained after the normal wash should not simply be rewashed in the normal process, when this has just been shown not to work. Stained rewash needs a dedicated and specially designed rewash process, with chemicals and conditions geared to the removal of stubborn staining. Items from this rewash should then be classified into items that are now stain-free and ready for use, those which need a final recovery process (because they are marked with metal or rust, for example) or the scrap heap.
- XOrbsTM in the Hydrofinity design not only reduce demand for heat energy, water and chemicals; they are also intended to attract stains from oily marks. This can make this particular machine a powerful tool, especially when combined with less aggressive but more ‘intelligent’ chemistry and regular servicing.
- XOrb attraction can extend to the black ‘snake-bite’ mark-off from the degradation of inter-compartmental seals on large continuous batch washers. These marks have resulted in widespread and catastrophic reduction in linen life in large rental stocks over the last few years, with total financial losses running into well over seven figures. The innovation in the Hydrofinity design shows just what can be achieved by combining novel design in the wash cage with modern detergency and stain removal. It is the oil in the rubber mark which is so attractive to the polymer bead, so the best chance of total removal relies on an immediate recovery process using the Hydrofinity.
How to monitor linen life
There should be no need to do time-consuming stock-takes in order to get a handle on linen life. The standard accounting technique for controlling a circulating stock of textile items is, firstly, to tot up the total number of issues of a particular classification over a given period – say six or twelve months. This total is then divided by the number of new items which you have had to inject in order to maintain the service with no shortages. If your total number of issues of king-sized duvet covers is say 151,093 over twelve months and you have had to inject 1,440 new covers in the period, then the average textile life = 151,093 ÷ 1,440 = 105 wash and use cycles.
This is not very good, because in theory a cotton duvet cover should easily last for 200 wash and use cycles and one made from cotton-rich should survive even longer. However, 105 cycles would be typical for a king-sized cover currently supplied by a high-volume textile rental business in the hotel market of a capital city.
The prize for raising textile life
This means that the potential saving by moving this up towards 200 cycles is over 45% of the budget for new textiles. If this could be achieved, it would mean a doubling in profit for many organisations, but the main benefit is the immediate removal of unnecessary expenditure on new textiles which should not really be needed. The first step to doing this is to get the wash process firmly under control, by measuring the present level of chemical damage and implementing each of the changes that have been made by those who are already leading the way (and which have been set out in this blog). The current level of damage can be gauged using a simple 25-wash test-piece. Improvements to the wash and rewash processes just calls for a competent detergent supplier. There is no investment needed – just a bit of modern laundry technology and a systematic approach!
We are living in challenging times, but the worldwide recovery is under way and looks like being faster than might have seemed possible just a few weeks ago. Getting textile life up to the level now being achieved by only a few will make an immediate contribution to cashflow and profitability. Now is the right time, whilst volumes are lower than they will be in just a few weeks’ time. Good hunting!
Written by Steve Anderton from LTC Worldwide - the UK's leading textile care specialists, regularly seen in the press.