Chromium-Free Leather Tanning Process Using Enzymatic Depilation
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional leather production processes are environmentally polluting due to the use of chromium, sulphides, and potassium permanganate, which also pose health risks through residual chemical presence in leather products.
Innovation Solution
A process for preparing leather that eliminates the use of chromium, sulphides, and potassium permanganate by employing enzymatic treatments, natural tanning agents, and biodegradable agents, such as essential oils and plant-based surfactants, throughout the unhairing, tanning, and bleaching stages.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional tanning processes use chromium compounds, then tanning effectiveness is improved, but environmental pollution and health risks increase
Solution Approach 1:
The invention extracts and removes chromium compounds from the tanning process entirely, replacing them with alternative agents such as vegetable tannins, aldehydes, or other non-chromium substances. This eliminates the harmful chromium residues that cause environmental pollution and allergic reactions while maintaining the essential tanning function of stabilizing and preserving the leather.
Solution Approach 2:
The invention changes the chemical parameters of the tanning process by substituting chromium-based chemistry with alternative chemical systems. This involves modifying the tanning agents, pH conditions, and reaction mechanisms to achieve effective tanning without chromium, thereby resolving the contradiction between tanning effectiveness and environmental safety.
2Productivity
If sulfides are used during peeling-scaling, then hair removal effectiveness is improved, but environmental pollution increases
Solution Approach 1:
The invention removes sulfides from the peeling-scaling process and replaces them with alternative agents such as enzymes (keratinases), oxidizing agents, or mechanical methods. This eliminates sulfide pollution while maintaining the effectiveness of hair and scale removal from the hide surface.
Solution Approach 2:
The invention replaces the chemical mechanism of sulfide-based peeling with alternative mechanisms such as enzymatic degradation of keratin, oxidative breakdown of hair structures, or controlled mechanical action. This substitution eliminates harmful sulfide discharge while achieving the same productivity in hair removal.
3Illumination intensity
If potassium permanganate is used during bleaching, then whitening effectiveness is improved, but environmental pollution and health risks increase
Solution Approach 1:
The invention extracts potassium permanganate from the bleaching process and replaces it with alternative whitening agents such as hydrogen peroxide, sodium hypochlorite, enzymatic bleaching agents, or optical brighteners. This eliminates permanganate residues that cause environmental pollution and skin allergies while maintaining the whitening and brightening effects on the leather.
4Reliability
If conventional multi-step processes are used, then leather quality is improved, but process duration increases to 27-29 days
Solution Approach 1:
The invention merges multiple conventional processing steps into integrated or simultaneous operations. For example, combining peeling and bleaching in one bath, or integrating tanning with finishing treatments, thereby reducing the total number of separate steps and the overall process duration from 27-29 days to a shorter cycle while maintaining leather quality.
Solution Approach 2:
The invention implements continuous processing where possible, eliminating idle time between steps and ensuring that each stage flows seamlessly into the next. This continuous action approach reduces the total process duration while maintaining the quality outcomes achieved by conventional multi-step methods.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach reduces environmental impact, minimizes health risks by eliminating harmful residues in the leather, and shortens the overall process duration compared to traditional methods.
Implementation Method 1
depilating the hide by enzymatic treatment in the absence of sulfide
Implementation Method 2
obtaining leather by tanning the hide in the absence of chrome
Implementation Method 3
optionally bleaching in the absence of permanganate
Data Source
AI summary
The present invention relates to a process for preparing leather from raw hide, the process being free of chromium, permanganate, and sulfide. This process comprises the following steps: - obtaining raw hide; - soaking the raw hide; - depilating the soaked hide by enzymatic treatment in the absence of sulfide; - fleshing the hide resulting from depilating; - pickling the hide; - obtaining leather by tanning the pickled hide in the absence of chromium; the hide being the skin of an animal selected from the group comprising crocodilians, snakes, and lizards. The present invention also relates to the leather crust obtainable by this process and its use in the fields of leather goods and watchmaking.