Great all-rounder

Since 1825 the drycleaning industry has used many solvents, the majority of which have now been abandoned as better and safer solutions became available. The last major solvent change came in 1994 when Hydrocarbon (a similar solvent to white spirit, last used by cleaners in the late 1960s) started to replace solvent 113 (Arklone). Hydrocarbon solvents are now well-established within the industry and are covered by the circle F dry cleaning symbols; at present Hydrocarbon and Perchloroethylene (Perc) are the only drycleaning solvents that have been approved for cleaning items carrying the circle F or circle P care labels. However, it is understood that GINETEX (the International Association for Textile Care Labelling) is now considering some of the newer solvents for inclusion in the garment care labelling code.

The first of these, Green Earth, was introduced in 1997 and was followed in later years by several others. Most machine manufactures, recognising the demand by the industry at large for alternatives to Perc and Hydrocarbon now produce multisolvent machines capable of accommodating new solvents such as Solvon K4, HIGlow, Intense, and Sensene.

Perchloroethylene

While Perc remains the most widely used drycleaning solvent throughout the world, in recent years it has come under increasing pressure from the environmental lobby; although it has extremely good solvent power and is a good solvent for well trained and experienced cleaners, however, having a KBV* (Kauri Butanol Value) of 92, colour bleeds, dye mark-offs and adverse effects on plastics, prints and finishes such as surface coatings, are always waiting around the corner to catch out the unwary. Being a high-density solvent with a specific gravity of 1.62, Perc also helps generate high mechanical action within the machine which is particularly important for the removal of deep seated and ingrained soiling but not so good for handling silks and delicates. Typical dry-to-dry times for Perc are 45-50 minutes

Hydrocarbon

Hydrocarbon solvents, the author thinks it is fair to say, are seen by the industry as being fairly safe and reliable. However, high drying temperatures of around 70C are required and mean that cleaners must exercise care in respect of heat sensitive items such as acrylic pile fabrics. With a KBV of 28 and density of 0.76, Hydrocarbon lacks the cleaning power and mechanical action of Perc needed for the efficient removal of deep seated medium to heavy soiling. This is particularly the case with the smaller cage sizes common in high street units. Hydrocarbon is, however, eminently suited for the cleaning of silks and delicate garments in general, but on a number of occasions, due to incomplete drying, customers have been known to suffer severe skin rashes which in some cases have needed hospitalisation.

Generally with Hydrocarbon there is a substantially reduced risk of dye bleeds, colour migration and dissolving beads compared to Perc. Dry-to-dry cleaning times are generally of the order of 75 minutes.

K4 solvent

K4 is generally regarded as environmentally friendly and there are now around 20 cleaners in the UK (1,200 worldwide) using K4. With a KBV of 75 and, it is claimed, a far better potential for removing waterbased stains and soiling than either Perc or Hydrocarbon, K4 is being increasingly seen by some within the industry as a good alternative to both the above solvents. K4 challenges Perc in terms of cleaning power and with a density of 0.83 helps generate slightly more mechanical action in the machine than Hydrocarbon but is, from this standpoint, still ideal for silks and delicate items. Like Hydrocarbon, K4 is flammable with a slightly higher flashpoint of 64.5C. Typical drying temperature is similar to hydrocarbon at 70C so once again a degree of caution is required when handling heat sensitive items. Dry to dry cleaning times with K4 are in the order of 84min for full loads reducing to 1hour for small or delicate loads. With regard to dye bleeds, plastics, beads and sequins, K4 is considered to be similar to Hydrocarbon. However, the effects will be very much dependent on process structure and solvent temperature.

How does K4 perform?

In this article, the author has mainly looked at K4 from a cleaning and finishing standpoint rather than through operation of the machine. Early in 2019 he delivered a five-day drycleaning course for a new business star- up using K4. The business, which had been in operation as a launderette offering a contractedout drycleaning service, was taken over five years ago and Maria, the new owner, had decided to develop her own inhouse drycleaning service and installed new equipment including a Union 18kg Multisolvent machine. Maria chose K4 after consulting widely with equipment and industry suppliers.

Particularly difficult areas for new starters are stain removal and learning to differentiate between no-risk items and those which could present a potential problem. While K4 does not eliminate the risk of colour bleeds, the need to test plastic beads and the like or heat sensitive risks, it did produce some very surprising results in the form of three old stock simulated fur coats containing up to 85% modacrylic fibre. The coats were all processed together and dried at 65C reducing to 60C. All responded well to cleaning with no evidence of adverse heat effects such as shrivelling of the modacrylic fibres which, quite frankly, the author had confidently expected.

These same coats cleaned in Perc would need to be handled with great care and in my view, to be safe, dried at no more than 45C. Garments cleaned in K4 generally had a pleasant handle when removed from the machine with no unpleasant odour. Stain removal in the machine was very good, finishing proved to be straightforward and the handle was noticeably softer than with Perc and about on a par with Hydrocarbon.

Experienced opinions

The author recently had the opportunity to spend some time on site with two very experienced cleaners, both of whom had changed over to K4.

Mike Ryan manages Cavels busy High Street unit in Gillingham and has had many years’ experience in the industry using Arklone, Hydrocarbon, Perc and Green Earth solvents. Mike changed to K4 seven years ago and has a 25kg Firbimatic machine. He rates K4 as better than any of the other solvents he has used, far better than Hydrocarbon and, in his own words, he “just could not go back to Perc”. Mike states that on two occasions in the past he has had issues with plastic beads which dissolved. This is a potential problem that has to be anticipated with any drycleaning solvent in use today.

Erdal Fahri, owner of Belmont Cleaners, Chislehurst, changed to K4 two years ago after 25 years with Perc. Erdal reluctantly made the change after experiencing health issues associated with exposure to Perc and has installed a Union 28kg machine. This is a busy unit typically cleaning five loads a day throughout the week. Erdal is very enthusiastic regarding K4 and reports that it has led to a huge reduction in the learning curve for new staff in terms of stain removal coupled with a substantial reduction in the need for the pre-treatment of water-based stains. He is now confident that his staff can safely handle items that might have been at risk in Perc. Furthermore he has only used 60 litres. of solvent – which is extremely frugal – since commissioning his new machine.

Both Mike and Erdal use the water spray technique for pre-treatment of some water- based staining. Water spraying has been employed by many cleaners over the years and involves spraying very lightly with a fine mist of water to assist with stain removal in the machine. While this technique can be very effective it can be a high-risk methodology for the inexperienced cleaner or those new to the industry. Mike and Erdal both stated that stain removal in the machine was very good but Presorb machine additive is essential for optimum results. Both agree that the main drawback with K4 is the dry-to-dry time of around 84min.

Conclusions

So is K4 a good alternative to Perc and Hydrocarbon ? The author has long held the view that the future of the drycleaning industry lies with the high end of the market and therefore with cleaners that have the equipment and the ability to safely handle a wide range of high value items.

Over the years he has trained many new-to-the-industry cleaners, covering all the major industry solvents In the case of K4 the author had no training issues relating to the solvent. Stain removal in the machine he considered to be better than Perc and Hydrocarbon with little sign of developed stains. The handle was pleasant and finishing straightforward. In other words, he found it an easy solvent to live with but for medium- to heavily-soiled robust garments and where productivity is an important factor, Perc would probably be his solvent of choice. However, in almost all retail environments, the cleaner receives a mix of work ranging from the above through to lightly soiled silks, delicates and household items.

Finally, bearing in mind that silks, delicates and high value items are much less at risk in a gentler low-density solvent and the fact that unexpected dye bleeds in particular are on the increase, choosing a less aggressive solvent than Perc, and one that substantially reduces the risks of mechanical damage and other adverse effects while still retaining excellent cleaning properties, deserves very serious consideration.

The best advice to those considering a change to K4 or any of the new solvents is to arrange to visit an experienced user, get some good independent advice, enquire about running costs and see for yourself how the solvent performs in a production environment.