Acetal Aldehydic Tanning Agent Composition for Homogeneous Hide Penetration
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Solution Overview
Problem
Existing tanning compositions based on aldehydic tanning agents face issues of high reactivity with skin proteins, leading to inhomogeneous tanning, especially in thick hides and skins, and pose health risks due to toxicity and pungent odors, necessitating improved occupational safety.
Innovation Solution
A composition comprising 5% to 95% acetal of an aldehydic tanning agent, 1% to 5% pH-regulating buffer, and 4% to 90% solvent, with a pH of 7.5 to 10.5, where the acetal is stable and non-reactive, allowing deep penetration and reduced toxicity, and can be activated by pH reduction to release the tannin for tanning, then fixed by pH increase.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If aldehydic tanning agents are used for tanning, then tanning effect is achieved, but penetration into deeper skin layers is insufficient and inhomogeneous tanning occurs
Solution Approach 1:
The patent applies preliminary action by first introducing the acetal form of the aldehydic tanning agent into the hide at alkaline pH, where it remains stable and non-reactive, allowing deep penetration without premature reaction. The actual tanning reaction is then activated later by acidification, ensuring homogeneous distribution throughout the hide thickness before crosslinking begins.
Solution Approach 2:
The patent utilizes parameter changes by controlling the pH throughout the tanning process. The hide is initially treated at alkaline pH (9-11) to prevent acetal hydrolysis and enable deep penetration, then the pH is gradually reduced to acidic levels (3-6) to activate the aldehydic groups for tanning reaction, achieving both deep penetration and homogeneous tanning.
2Reliability
If aldehydic tanning agents are used for tanning, then tanning effect is achieved, but toxicity and pungent odor increase health risks
Solution Approach 1:
The patent changes the chemical form of the tanning agent by using acetals instead of free aldehydes at the treatment pH. Acetals are stable, non-toxic, and odorless compounds that do not release harmful aldehydic vapors under alkaline conditions, thereby eliminating health risks during application while maintaining tanning effectiveness through subsequent acidification.
Solution Approach 2:
The acetal acts as an intermediary compound that carries the tanning agent through the hide without releasing harmful aldehydes. It serves as a stable carrier form that can be safely handled and applied, then converted to the active tanning form only when needed through pH reduction, mediating between safety and effectiveness.
3Reliability
If aldehydic tanning agents are used for tanning, then tanning reaction occurs, but reactivity is too high causing insufficient penetration
Solution Approach 1:
The patent applies preliminary action by introducing the acetal form of the aldehydic tanning agent into the hide at alkaline pH, where it remains stable and non-reactive, allowing deep penetration without premature reaction. The actual tanning reaction is then activated later by acidification, ensuring homogeneous distribution throughout the hide thickness before crosslinking begins.
Solution Approach 2:
The patent inverts the conventional approach by using the less reactive acetal form first for penetration, then converting it to the reactive aldehyde form through pH reduction. This reverses the typical sequence where the reactive form is applied first, enabling deep penetration before activation and achieving homogeneous tanning throughout the hide.
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 composition achieves homogeneous tanning with improved penetration and reduced toxicity, enhancing occupational safety by minimizing exposure to aldehydic vapors and allowing safer handling.
Implementation Method 1
Acetals of this type are particularly stable in neutral and alkaline mediums and for this reason do not react with the proteins mentioned when the composition according to the invention is applied to the skin and/or fur at this pH value. After the composition according to the invention has been applied to skin and/or fur to be tanned, the pH value can be reduced after an exposure time in such a way that the aldehydic tanning agent is released and thereby becomes reactive.
Data Source
AI summary
The invention relates to a composition containing an acetal of an aldehydic tanning agent for tanning hides and/or pelts and to a method for tanning hides and/or pelts in order to produce leather, wherein an acetal of an aldehydic tanning agent is used. By lowering the pH value, the aldehydic tanning agent can be released, whereby a tanning step is initiated. The composition and the method according to the invention are characterized by a lower toxicity compared to conventional compositions and tanning methods based on aldehydic tanning agents. Furthermore, an improved penetration of the tanning agents into deeper layers of the hide and/or the pelt is facilitated such that a particularly homogeneous tanning is achieved.