Leather processing utilizing super-critical or near super-critical co2 value
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Solution Overview
Problem
Conventional leather processing methods are water- and chemical-intensive, generating waste and struggling to efficiently improve lower-grade leathers, particularly in drying, fat-liquoring, and dyeing processes, which are time-consuming and environmentally unfriendly.
Innovation Solution
A method utilizing supercritical or near-supercritical CO2 to process various leathers, including drying, fat-liquoring, dyeing, coating, and waterproofing, under increased pressure and temperature, minimizing water and chemical use, and enabling efficient, homogeneous dyeing without waste.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional water-based and chemical-intensive methods are used for leather processing, then leather quality can be maintained, but environmental pollution increases and waste is generated
Solution Approach 1:
The patent changes the physical state and properties of the processing medium from liquid water to supercritical CO2 by adjusting temperature and pressure parameters. This transformation allows the same processing functions (drying, fat-liquoring, dyeing) to be performed without water, eliminating wastewater generation while maintaining leather quality through controlled parameter variations.
Solution Approach 2:
The patent utilizes the phase transition of CO2 between supercritical and gaseous states. By controlling pressure and temperature, CO2 transitions to a supercritical state for processing, then returns to gaseous state for easy separation and removal, leaving no residual pollution. This phase transition mechanism enables complete elimination of processing waste.
2Productivity
If conventional drying, fat-liquoring, and dyeing processes are used, then leather can be processed, but the processes are time-consuming and require multiple separate steps
Solution Approach 1:
The patent merges multiple separate leather processing operations (drying, fat-liquoring, dyeing) into a single integrated process using supercritical CO2. The supercritical fluid simultaneously performs all these functions in one continuous operation, eliminating the need for separate processing steps and significantly reducing total processing time.
Solution Approach 2:
The supercritical CO2 serves multiple functions simultaneously: it acts as a drying agent to remove moisture, a fat-liquoring medium to soften the leather, and a dyeing carrier to impart color. This multi-functionality of a single processing medium streamlines the entire leather treatment process.
3Illumination intensity
If conventional dyeing methods are used to achieve high colour brightness and intensity, then leather appearance is improved, but chemical usage and waste generation increase
Solution Approach 1:
The patent changes the dyeing medium from liquid chemical solvents to supercritical CO2, altering the physical state of the processing fluid. This parameter change enables effective dye penetration and color development without requiring large amounts of chemical solvents, thereby reducing waste while achieving the desired color brightness and intensity.
Solution Approach 2:
The supercritical CO2 acts as an intermediary carrier that transports dye molecules to the leather substrate. This intermediary medium facilitates efficient dye delivery and distribution, achieving uniform and intense coloring while the CO2 itself can be easily separated and reused, minimizing chemical waste.
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
The method achieves high-quality leather processing with reduced waste, improved efficiency, and cost-effectiveness, maintaining leather quality and functionality while reducing environmental impact.
Implementation Method 1
processing said leather by subjecting the leather to super critical CO2 under increased pressure of > 0.01MPa, a temperature of >30 °C, during a period of > 1 minute
Implementation Method 2
processing comprise at least one of (a) drying leather
Implementation Method 3
processing comprise at least one of (b) fat-liquoring leather, also referred to as softening leather
Implementation Method 4
processing comprise at least one of (c) dyeing tanned and dried leather, or fat-liquored leather, or finished leather
Data Source
Figure 1
Figure 2a~4b
Figure 5a~7
AI summary
The present invention is in the field of a method for processing natural of synthetic leather by using super-critical CO2. The leather can be dried leather low grade leathers, thin leather, crust leathers, finished leathers, wet blue leathers, and tanned leather, as well as synthetic leather. In a second aspect the invention relates to leather obtained by said method, and in a third aspect to a stand-alone apparatus for performing said method.