Graft Polymer Deliming Composition for Ammonia-Free Hide Processing
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Solution Overview
Problem
Existing deliming agents for hides in leather production, such as ammonium salts, cause environmental pollution and health hazards due to ammonia gas release and high ammonia nitrogen in wastewater, while alternative agents like butyrolactone and cyclic carbonates have slow hydrolysis rates, and polysuccinimide is slow to penetrate the hide.
Innovation Solution
A deliming composition using graft polymers of polysaccharides and polypeptides, obtained through radical polymerization, which are water-soluble and derived from renewable natural polymers, effectively reduce pH without using ammonium salts, ensuring efficient penetration and avoiding protein precipitation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If ammonium salts are used as deliming agents, then pH control is improved and deliming effectiveness is enhanced, but ammonia gas is released causing odor nuisance and respiratory irritation, and wastewater contains high ammonia nitrogen requiring environmental regulations
Solution Approach 1:
The patent changes the chemical composition parameter by replacing ammonium salts with amino acid-containing compounds (such as amino acid salts, amino acid esters, or amino acid amides). This substitution fundamentally alters the deliming agent's chemical properties, eliminating ammonia gas release while maintaining pH buffering capacity through the amino acid's carboxyl and amino groups that can accept and donate protons.
Solution Approach 2:
The patent employs amino acid-containing compounds that are biodegradable and environmentally friendly, replacing persistent ammonium salts. These amino acid-based deliming agents break down into harmless substances, eliminating long-term environmental contamination while providing effective deliming action.
2Manufacturing precision
If acids are added to delim hides, then pH is reduced effectively, but pH may fall below the isoelectric point of protein causing protein precipitation and deposit on hide surface
Solution Approach 1:
The patent employs amino acid-containing compounds that provide beforehand cushioning through their buffer system. The amino acid's carboxyl group (COOH) and amino group (NH2) create a buffering capacity that prevents pH from dropping below the isoelectric point of hide proteins, cushioning against excessive acidification before it can occur. This prevents protein precipitation while still achieving effective deliming.
3Device complexity
If conventional deliming agents are used, then deliming process is simple, but operating times are too long for practical purposes due to slow hydrolysis
Solution Approach 1:
The patent changes the chemical structure parameter by using amino acid-containing compounds with specific functional groups that enhance reactivity. The amino acid structure provides both buffering capacity and effective calcium complexing ability, achieving rapid deliming action without requiring prolonged operating times, thus improving productivity while maintaining process simplicity.
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 use of graft polymers reduces environmental impact by minimizing ammonia release and wastewater pollution, enhances processing efficiency, and maintains hide quality by preventing protein deposition, while being derived from renewable resources.
Implementation Method 1
The pH ought to be reduced by a deliming agent even down into the cross section of the hides
Implementation Method 2
addition of acids or acidic salts which form very highly soluble complexes with the calcium ions so that they can be removed with the wastewater
Data Source
AI summary
A deliming composition and a deliming method using graft polymers from polysaccharides and/or polypeptides or the corresponding derivatives, obtainable by radical polymerization of a monomer, selected at least from, or a monomer mixture of, acrylic acid or methacrylic acid or the mixtures thereof.