One of the first companies in the sector to offer metal-free tanning solutions is undoubtedly KLF Tecnokimica which for years has been developing a valid tanning process as alternative to the classic systems deriving from the use of metal salts (such as chromium, aluminum, zirconium and titanium) which makes it possible to obtain white leathers with a shrinkage temperature of approximately 80 ° C and metal concentration values at the end of the process that easily fall within the regulations in force.
“Our metal free tanning process is fast and works very well – explains KLF – It is based on the combined action of two chemicals, Parolit FC and Parolit JX, whose basic constitution is organic, capable of fixing themselves on the collagen fibre by forming a stable complex equal to that of a normal natural tannin”. The tanning phase to obtain a good swelling of the collagen fibres that this way prepare to receive and optimise the synthetic products used in the subsequent retanning phase is essential in this system. “The combination of the two products guarantees a tanning stability comparable to that of glutaraldehyde and natural tannins with the advantage of producing white leathers and with absolutely superior light resistance” ensures the Tuscan company led by Marco Frediani.
“Leathers handled like this are also reactive to the fattening products that are fixed to the fibre giving the desired softness”. What is the final result? “In addition to being exceptionally soft, finished leathers offer full and brilliant dyeing tones and respectable technical-physical characteristics able to satisfy all demands of the market and fashion industry” declare KLF Tecnokimica’s experts.
The Tuscan company also ensures that the products used in the retanning and fattening phase have a high depletion, are free or at irrelevant content of free formaldehyde and exhibit excellent resistance to light.
Recently KLF Tecnokimica has selected a wide range of metal-free anilines including Kolorfluo anilines. It is a range of fluorescent dyes reactive to ultraviolet (UV) light that can be used both individually and in mixture with each other or with commonly used acid dyes. “The final results are tones of exceptional brilliance and brightness obtainable with rates ranging from 0.3% to a maximum of 3% on shaved weight” explains the Tuscan company.