On the whiteness trail
The Hohenstein Institute is researching new methods to combat the premature greying of white linen through sustainable processes at predictable costs.
BÖNNIGHEIM (ak) The hotel sector, health care system and food industry generate huge amounts of linen every day which is becoming increasingly expensive to treat and care for due rising energy costs. Therefore manufacturers of commercial washing machines have developed modern washing procedures with low water consumption and correspondingly lower heating requirements. Both in-house laundries and rental service companies are further reducing their need for fresh water through recovery systems.
Normal washing procedures and the detergents used are hardly able to keep up with these developments. "Modern washing processes with a low water usage present specific challenges to the chemical/physical effect of detergents. Any dirt removed must be held as a stable solution (dispersion) in the water, so that it does not soak back into the fibre," explains project manager Eva Gierling. In order to provide effective protection against redisposition, in other words to stop the removed dirt pigments soaking back into the textile, the researchers want to identify suitable detergent additives and develop procedural recommendations.
These are focused in particular on the specific residues of cosmetic products and personal hygiene products (silicone and polyquaternium)which cause a disproportionate, non-reversible greying of white textiles made of mixed cotton-polyester fabrics. This leads to a considerable reduction in the lifespan of towels, bedding, top table cloths and other workwear worn in "white sectors".
Within the framework of an ongoing research project (AiF-Nr. 17562N), the Hohenstein Institute is researching innovative, sustainable solutions which will maintain the value of textiles over the long term, guarantee a high level of process security and as a result lead to stable laundry costs.
Using innovative test soilings based on high stain substances such as cosmetics, the Hohenstein Institute is investigating the properties of detergent solutions, in other words scouring baths, and how they hold dirt in the solution and prevent it soaking back in to the fibres (dispersion properties). The dirt removal of dust/soot/sebum combinations, make-up and curry-paste is then collated and assessed means of an assessment matrix also developed by the Hohenstein scientists. This also forms the basis upon which the effectiveness of detergents made of both known and innovative additives, including dispersing agents, colour and greying inhibitors on the washing result can be investigated.
The newly acquired knowledge will be used for the formulation of a sample recipe for a detergent and the development of an appropriate washing procedure for hotel textiles and white workwear. In future commercial laundries, manufacturers of detergents, industrial washing machines and systems, as well as textile producers will be able to make use of this information in the development of sustainable systems.