Cyclodextrin-Based Inclusion Compound for Metal-Free Leather Tanning

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

The tanning industry faces significant environmental and toxicological challenges due to the use of chromium salts and aldehydes, which contaminate wastewater and pose health hazards, while existing synthetic tanning agents, or syntans, although metal-free, are poorly biodegradable and inefficient in tanning processes.

Innovation Solution

A cyclodextrin-based inclusion compound is developed, combining with synthetic tanning agents through polycondensation reactions, forming strong interactions with leather and optimizing tanning processes, including dyeing and odor masking, while ensuring metal-free and environmentally friendly operations.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If chromium salts are used for tanning, then the tanning process achieves good leather properties, but the environmental impact and water pollution increase significantly

Engineering Contradiction:
Improvetanning process effectivenessVSAvoidenvironmental impact and water pollution
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

Cyclodextrin inclusion compounds act as intermediaries that carry and deliver tanning agents to the leather substrate. The cyclodextrin host molecules form inclusion complexes with tanning agents, enabling controlled release and improved penetration while reducing direct contact between free tanning agents and wastewater, thus lowering environmental impact while maintaining tanning effectiveness

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The invention uses composite cyclodextrin inclusion compounds combining the host cyclodextrin structure with guest tanning agent molecules. This composite approach allows the system to leverage the water solubility and penetration ability of cyclodextrins while delivering the tanning functionality of the embedded agents, achieving effective tanning with reduced pollution

Inventive Principle:
Principle #40Composite materials

2Object-affected harmful factors

If synthetic tanning agents (syntans) are used to avoid metals, then the environmental impact is reduced, but the biodegradability and tanning efficiency remain poor

Engineering Contradiction:
Improvemetal content in leatherVSAvoidtanning efficiency and biodegradability
Core Design Contradiction:
Object-affected harmful factorsVSReliability

Solution Approach 1:

Cyclodextrins serve as intermediary carriers that enhance the performance of synthetic tanning agents. The inclusion complex structure improves the water solubility, penetration ability, and controlled release of syntans, thereby achieving better tanning efficiency while maintaining the metal-free advantage. The cyclodextrin shell also improves biodegradability compared to conventional syntans

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The invention changes the physical and chemical parameters of synthetic tanning agents by encapsulating them in cyclodextrin inclusion compounds. This modification improves water solubility, penetration rate, and controlled release characteristics, transforming poor-performing syntans into effective tanning agents with enhanced efficiency and biodegradability

Inventive Principle:
Principle #35Parameter changes

3Loss of substance

If conventional tanning agents are used, then the tanning bath exhaustion is poor, but this results in reduced contamination of wastewater

Engineering Contradiction:
Improvetanning bath exhaustionVSAvoidwastewater contamination
Core Design Contradiction:
Loss of substanceVSObject-affected harmful factors

Solution Approach 1:

The cyclodextrin inclusion compounds enable periodic or staged release of tanning agents during the tanning process. The inclusion complexes gradually dissociate and release the embedded tanning agents over time, achieving progressive penetration and exhaustion of the tanning bath, which improves both efficiency and reduces sudden pollutant discharge

Inventive Principle:
Principle #19Periodic action

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 cyclodextrin-based compound achieves excellent chemical and physical properties in leather, such as improved shrinkage temperature, thickness, and resistance, along with efficient dyeing and odor masking, while minimizing chemical waste and pollution, thus reducing the environmental impact of tanning processes.

Implementation Method 1

a cyclodextrin-based inclusion compound with at least one synthetic tanning agent

Methodology Applied
Scientific EffectInclusion compound formation: Absorption (physical)

Implementation Method 2

Formation of strong and stable chemical interaction with the functional groups of the leather proteins

Methodology Applied
Scientific EffectChemical interaction with functional groups: Chemical Bonding

Data Source

PatentEP4249553B1Leather or retanning compound with cyclodextrin-based inclusion compound
Publication Date: 2024.12.11 BI QEM PTE LTD
  • EP4249553B1 patent drawingFigure 1~2
  • EP4249553B1 patent drawingFigure 3

AI summary

Leather tanning or retanning compound with inclusion compound based on cyclodextrin and at least one synthetic tanning agent.