Black split velour for lining and upper leather: This article meets the challenging requirements in wet-end, dyeing and retanning processing.
This often requested article provides some of the most challenging requirements in wet-end, dyeing and retanning processing, such as:
To achieve these requirements we use the new SELLA HiFA system in a modified 2-step process. Important is to minimise the use of anionic retanning and fatliquoring agents in the crusting step, in order to allow the build up and fixation of the SELLA HiFA system in the subsequent process.
The main problem is to ensure good removal of the buffing dust before the first dyestuff addition. Therefore one anionic and one cationic washing process start the dyeing procedure. After the application of the 3 step SELLA HiFA system (SELLA HiFA Pre, SELLA HiFA Bond, SELLA HiFA Black), the washing processes are extremely important in order to avoid the transportation of unbound dyestuff through the later processes. To achieve the high rubbing fast properties it is important to prevent a classical fixation of the unbound dyestuff after the SELLA HiFA treatment. Therefore the washing processes and the second treatment with SELLA HiFA Pre and SELLA HiFA Bond are necessary.
The fatliquoring can strongly influence the intensity of shade and the fastness properties. For moisture regulation and excellent washability, a combination of CORIPOL BZN, MAGNOPAL SOF and EUPILON WAS-1 was used.
The metal salt fixation is used to optimise the fixation of the washable fatliquoring agents and not necessarily to achieve certain water resistance.
As the final top fatliquoring, a combination of EULINOL TMS and RODA MOD 2081 is applied. This treatment intensifies the shade and adds additional surface handle to the velour. This after-treatment can also help to improve the dry and wet rubbing fastness properties and the gloss of the nap.
If trials are done with the SELLA HiFA system it can be noticed that the wet crust leather can be handled much easier through the mechanical operations like setting out and vacuum drying compared to conventionally dyed black leather.
The excellent fixation helps to keep machinery and hands cleaner. This can be observed also when the leather is unloaded from the drum and horsed up.
To check the effectiveness of the SELLA HiFA system try a simple hand washing test with normal soap under warm water. A washing test comparison to conventionally dyed black leather can also be carried out on the dry crust leather.