Bayer specialities for patent leather finishing

Patent leather, once reserved for special occasions, has now become a popular and easy-care upper material for fashionable and casual shoes for everyday wear and for accessories. Bayer Chemicals, a division of Bayer AG, have unveiled their latest development, Baygen Hardener CF, an isocyanate-based crosslinking agent, which noticeably improves the performance properties of patent leather even during the cold winter months, giving excellent cold flex resistance which largely prevents cracking of the finish. High-gloss patent for leathergoods - in particular shoes - which are both fashionable and easy-care can be produced with a combination of Baygen Top U 01 and Baygen Hardener SN 01. If Baygen Top U 01 is combined with Baygen Top MS, different matt effects can be obtained by varying the mixing ratio. The advantages of these polyurethane lacquer systems - good scuff and scratch resistance, thermostability - come to the fore especially when producing leather with the currently fashionable negative embossing patterns, where the material is subjected to high mechanical strain, eg during dry-drumming. Problems often arise in the machine production of shoes when the leather is shaped at high temperatures, as the 'overstretched' leather then tends to crack during the thermosetting process. This can be prevented by using Baygen Top TF, a polyester lacquer with extremely good heat resistance. After crosslinking and drying, the patent leather can be stretched by up to 30% even at temperatures of 120°C. All lacquers based on Baygen Top can be applied by the highly economical curtain-coating method. Pale and pastel shades represent a particular challenge to manufacturers of patent leather, as these delicate colours require extremely good lightfastness and resistance to yellowing. To meet the special demands of such finishes, Baygen Hardener LR was developed - a lightfast, isocyanate-based crosslinking agent for two-component patent finishing. Its fastness to Xenolight of four to five is about two to three grades better than that of conventional hardeners. Bayer are one of the few companies which supply all the chemicals required by the leather industry, including inorganic and synthetic tanning materials, preservatives and fatliquoring agents, dyestuffs and tanning and finishing agents. Details of the entire range of products and the names of local contacts can be found on the Internet under http://www.bayerleather.com