Langro launch UV finishing process1 January 2002
Langro-Chemie's new UV-leather finishing process provides top quality leather with superb malleability and a first class finish, while at the same time significantly enhancing the durability, strength and longevity of the leather. Using Langro's newly developed treatment, the resistance of the leather to fatigue and wear and tear is greatly enhanced, without detracting from the leathers natural qualities and characteristics. The UV-treatment process utilises a completely different reaction process than any present day processes. In other words, the new system instigates a reaction within the C=C (carbon double bonds) of the chemical groups contained within the polyurethane structure. During exposure to ultra violet light, the photo-initiator splits into two radicals which react specifically with the carbon-carbon double bonds in the pu. Following the radical polymerisation, the pu and photo-initiator react, resulting in one reactive radical causing further chain reactions with the pu. The result of the reactions causes the pu chemical chain to break down into varying lengths. First, the leather is chemically treated and allowed to dry. Then the leather is passed through the UV-polymerisation drier where it is exposed to a photo-initiator illumination process. During this exposure period, the treated polyurethane reacts with the photo-initiator. As a result of this treatment, the interwoven chemical chain of the polyurethane is divided into varying lengths. This division influences the relationship between the flexibility and the durability of the leather. This process has several environmental advantages over existing systems and can be used on all types of leather. UV polymerisation drier In order to use this process, a source of UV rays must be installed in the tannery. Langro-Chemie have developed the new process using a UV-Mercury steam lamp with 90 W/cm. The typical speed of leather passing through the drier is 8m/min. The exposure/reaction time of the leather is controlled by adjusting the transfer belt speed through the drier.