Consequently, there is a demand for finishes that prevent leather from becoming soiled so quickly and/or make it easier to clean. The new Aquaderm X-Shield system from LANXESS claims to do both – and the effect is long-lasting, too.
Chemists and leather experts from LANXESS and Daikin Industries have, for the first time, succeeded in anchoring organic, soil-repellent fluorine products firmly on the surface of the leather so that they are not worn off by mechanical abrasion.
The innovative system is a VOC-free, aqueous dispersion that is applied to the leather like a normal top coat. By varying the quantities of the two components Aquaderm X-Shield G and Aquaderm X-Shield M, it is also possible to adjust any desired gloss level.
LANXESS’s leather business unit will in future be responsible for marketing the new range of products for leather applications such as car seats, furniture and shoe uppers. At the same time, Daikin will use the technology to develop antisoiling products for other sectors such as the automotive, construction and aeronautical industries. By cooperating in this way in the development and marketing of antisoiling systems, each company will benefit from the other’s experience and worldwide service and sales network, thereby opening up possibilities for new products and applications.
‘In the past, the problem of soiling was avoided by sticking to interior colours that don’t show up the dirt’, says Stefan Wildbrett, a leather expert at LANXESS. ‘Now, however, fashion trends have to be taken into consideration when choosing colours. Our task, therefore, as experienced manufacturers of leather finishes, was to offer our customers a means of meeting this challenge.’ The first attempted solution to the problem, which achieved promising results in the market, was a system based on fluorine chemicals that were applied to the finished leather, where they prevented soiling on account of their low surface tension.
‘This system made use of the fact that special fluorinated polymers possess both water and oil-repellent properties’, says Wildbrett. Now the problem is being tackled with a new binder system with polytetrafluoroethene (PTFE) segments incorporated by polymerization. ‘Dirt particles are repelled and liquids simply form beads on PTFE films like fat in a coated frying pan’, explains Wildbrett.
The trouble with conventional systems is that the soil-repellent substances gradually wear off. ‘We have now successfully overcome this problem’, says Wildbrett. ‘Thanks to LANXESS’s comprehensive know-how in the field of polymer production, we have succeeded in developing an antisoiling system in which the fluorine components manufactured by our partner Daikin are combined with our polymer technology in the form of an aqueous dispersion.’ Aquaderm X-Shield is applied on the leather like a normal top coat and is firmly anchored on the surface. As little as 0.4 gram (dry weight) per sq ft is sufficient to produce a cohesive, soil-repellent film that provides the leather with long-lasting protection.
Additives such as pigments can also be incorporated into the binder system in the usual way, making it possible to obtain the desired shade. The gloss level can be adjusted by varying the ratio of the two components Aquaderm X-Shield G and Aquaderm X-Shield M. The system’s effectiveness has been proven in trials and Aquaderm X-Shield passes the current soiling tests required by the automotive industry.
It not only protects leather surfaces from normal dirt, leather finished with Aquaderm X-Shield also performs noticeably better than comparable samples with conventional antisoiling finishes when it comes to stains caused by more unusual substances such as mustard, coffee, ketchup, marker pen inks and even engine oil. The new system also makes cleaning with leather-care products considerably simpler. ‘It is particularly important that the soil-repellent effect is long-lasting – we reckon that it should last as long as other efficient polyurethane top coats’, remarks Wildbrett.
Aquaderm X-Shield also compares favourably with conventional finishes on other factors such as surface touch, which had been a disadvantage with earlier fluorocarbon finishes, but can now be modified as the customer wishes. Guide recipes from LANXESS produce excellent stick/slip properties and a pleasant, squeak-free surface touch.