Drycleaning technology

Modern fabric care requires modern cleaning methods

3 December 2010



Richard Neale looks back at the early days of drycleaning and asks whether drycleaning is likely to be with us in another 125 years time


If the use of turpentine to remove grease and oil spots could be described as “drycleaning” then, according to the Guild of Cleaners and Launderers, drycleaning probably started around 1716.

Development of this into a service with the first glimmerings of the equipment and technology we know today had to wait until 1825, when Frenchman Jean-Baptiste Jolly became drycleaning’s first true entrepreneur with his camphene-based process.

By the time the forerunners of Laundry and Cleaning News came on the scene, drycleaning using white spirit was well established.

Over the next 125 years it was to change out of all recognition, with each generation adding to the quality, capability and productivity of this growing sector.

Because the French entrepreneur was a dyer the practice of drycleaning would have been adopted in many dye-houses. The service would have been established nationwide.

As the laundry sector became industrialised from 1920 onwards, with the installation of steam boilers and multi-roll ironers, every major laundry would have had a drycleaning department.

Drycleaning was thus a factory-based operation using first camphene, then benzine (a petroleum fraction rich in aromatic compounds) and later white spirit (a much healthier substitute for benzine).

The industry became standardised on trichloroethylene, in parallel with many white spirit plants. This trend started in the 1920s and continued through until the 1950s when the success of triacetate fabrics started the conversion to perc (perchloroethylene) which does not damage acetate in the way that trichloroethylene does.

White spirit drycleaning was characterised by practices which would horrify the factory inspector of today. The wash stage was carried out in a side loading rotary washing machine and the work would be transferred manually to a high speed extractor and then again by hand to a free-standing tumble dryer.

Apart from some exposure to fumes from the washing machine, the main risk was fire in the tumble dryer, a risk which quite frequently became a reality.

Stain removal techniques were being developed, mainly with pure chemicals such as acetic acid, caustic soda, ammonia and hydrogen peroxide. The dedicated spotter became a highly skilled and highly respected member of the team, able to remove stains safely from a wide range of silk and other natural fibre fabrics.

An experienced spotter might accumulate a range of 50 – 100 different chemicals to constitute an impressive armoury.

The 1930s saw the development of the first integrated machines for washing, drying and even solvent purification. However, separate distillation stills were the norm for most trichloroethylene and perchloroethylene installations.

Manual controllers were gradually superceded by card controls, so that an unskilled operative could start a program sequence.

In the 1950s, the unit shop revolution began and every high street in the UK had its own on-site cleaning. This necessitated the development of the fully integrated perchloroethylene machine with integral distillation. These were boom times for the manufacturers, with large cleaning chains taking over 100 machines each and replacing factory operations to a large extent.

Perc (perchloroethylene) is a powerful solvent, scoring 90 on the Kauri-butanol (Kb) scale as against 30 for white spirit. This gave problems with some dye recipes and serious problems with polystyrene bead trims, which melted in contact with the solvent.

This led to the search for a universal panacea and the industry thought that it had found it with solvent R113, a chlorofluorocarbon originally developed for and widely used in refrigeration. This had none of the odour problems of perc and caused little dye or trim damage so fluorocarbon machines enjoyed good sales through the 1980s.

Fluorocarbon has a Kb value of 30, making it no stronger than the old white spirit. This meant that stain removal skills, which had become neglected with trichloroethylene and perc, had to be rediscovered. Training the next generation of spotters became essential but this would have needed considerable time so the industry adopted the proprietary spotting kit.

The simplest kits contained three chemical mixtures, a slightly acidic oxidising blend for vegetable dye stains; a slightly alkaline mixture for human body fluids and a solvent mixture for dry-side stains.

This development, together with the computer controller, set the industry onto a path of de-skilling which continues today.

The demise of fluorocarbon became inevitable in 1988 when Margaret Thatcher signed (on behalf of the UK) the Montreal Protocol in which governments worldwide acknowledged the damage to the ozone layer in the upper atmosphere. This damage was believed to be caused by emissions of fluorocarbon solvents amongst others.

In the UK, the government initiated and part funded a research project to demonstrate the effectiveness of hydrocarbon solvent to replace fluorocarbon.

The project was led by UK leather cleaner Master Services Group which, with help from Johnson Cleaners UK and the Next retail group, held demonstrations to convince the sector that hydrocarbon solvent could replace fluorocarbon and eventually perc.

Work in the USA revealed another potential safe solvent – a silicone derivative with a cyclosiloxane radical. This offered an ecologically attractive solvent which was even more gentle than hydrocarbon. Its Kb value was just 12, so its effect on most plastics was nil and it did not affect any of the common dyeing methods. It also addressed the continued decline in the reliability of drycleaning care labelling and the poor resistance of fashion items in particular to any form of drycleaning.

With the effective and emotive trade name GreenEarth, there are currently over 200 cyclosiloxane machines in the UK and many more in the USA, Canada and Europe.

The low Kb value of cyclosiloxane means that stain and soil pre-treatment have again come to the fore and the success of the GreenEarth cleaner is dictated by the combination of craft skills of 50 years ago and the effectiveness of the specially adapted proprietary spotting kits that have been rapidly assembled to meet the need.

There was a spin-off of work from the American space programme which led to the construction of the first drycleaning machines to use liquid carbon dioxide. Although the solvent never succeeded in safely replicating water in its ability to dissolve water-based staining without pre-treatment, some drycleaners are using carbon dioxide with great success. If cyclosiloxane had not become available at the same time it is probable that carbon dioxide cleaning would have been even more successful.

Against this, we have to set the increasing environmental regulatory regime which started during the 1980s, gathered pace in the 1990s and now dominates the industry.

When the UK’s Textile Services Association put together its first Safety in Drycleaning Guidelines in the 1970s, the title did nor refer to health or environmental management and these terms were only added in the 1980s. Now environmental demands take up an ever increasing amount of chief executive time.

The Solvent Emission Directive issued by the EU sets out rules for every sector which emits volatile organic compounds and drycleaning has its own section.

This has led to trained environmental health officers from every town council monitoring the efficiency with which every individual cleaner uses solvent.

UK cleaners now require an annual licence to emit solvent vapours and face the risk of loss of this permit to trade if they do not meet strictly enforced requirements.

All of this has led many to re-think the case for washing or wetcleaning. Whereas washing produces known problems for many fabrics and dyes, far less is known and understood about modern wetcleaning.

The use of a large cage machine, with special chemicals which protect the fabric, together with low temperature and much reduced mechanical action have resulted in entirely new meanings for the term wetcleaning. It is now possible to safely wetclean most cotton and wool garments, together with cashmere, mohair and angora and a wide variety of other blends.

Silk, viscose and acetate require special care and skill, but wetcleaning has come of age and for heavy water-based soiling it has become the cleaning method of choice. The secret of success lies as much in the finishing techniques and equipment as in the cleaning itself.

Where will the industry go in the next 125 years? It is surprising that fashion has not yet produced garments that are so easy to clean that the very mildest solvents will lift soil and stains from them without pre-spotting.

The reason for this might lie in the attraction for the consumer of natural fabrics which breathe and flex. Resin finished plastic fabrics might shed stains but they must meet the wearer’s comfort criteria.

Drycleaning and wetcleaning are still likely to be with us in 125 years time, but man’s ingenuity makes it impossible to predict in what guise this will be.




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