Recycled Fibre Dissolving Pulp via Cold Alkaline Extraction
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Solution Overview
Problem
The demand for dissolving pulps has exceeded supply, leading to high prices, and existing methods struggle to produce high-quality pulps from recycled cellulosic fibers due to their degraded mechanical properties and impurities.
Innovation Solution
A method involving cold alkaline extraction and bleaching treatments is used to process recycled papers and cardboards, reducing lignin and hemicellulose content, and removing impurities to produce dissolving pulps with improved properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If recycled cellulosic fibers are used as feedstock, then supply volume and cost-effectiveness are improved, but mechanical properties and purity deteriorate due to degradation and impurities
Solution Approach 1:
The patent applies parameter changes by modifying the chemical composition parameters of recycled fibers through controlled alkaline extraction and bleaching processes. These treatments selectively remove lignin and hemicelluloses while preserving cellulose integrity, thereby improving purity and mechanical properties suitable for dissolving pulp applications
Solution Approach 2:
The patent employs strong oxidizing agents in the bleaching stage to accelerate the removal of lignin and other impurities from recycled fibers. This oxidation process effectively degrades harmful components while maintaining cellulose structure, resolving the contradiction between using low-cost recycled material and achieving high mechanical properties
2Quantity of substance
If recycled cellulosic fibers are used as feedstock, then supply volume and cost-effectiveness are improved, but purity deteriorates due to contaminants and dirt
Solution Approach 1:
The patent applies extraction principles through cold alkaline extraction and bleaching treatments that selectively remove unwanted components (lignin, hemicelluloses, contaminants) from recycled fibers. This separation process effectively purifies the cellulose while maintaining the benefits of using abundant recycled feedstock
Solution Approach 2:
Strong oxidizing agents are used to accelerate the removal of impurities and contaminants during the bleaching stage, achieving high purity levels from low-quality recycled materials through enhanced oxidation reactions that selectively target harmful substances
3Manufacturing precision
If conventional cooking methods are used for wood raw-materials, then dissolving pulp quality is improved, but supply limitation and high cost persist due to raw material constraints
Solution Approach 1:
The patent applies universality by developing a multi-functional processing system that can handle various types of cellulosic materials (wood, recycled paper, agricultural residues) through the same alkaline extraction and bleaching工艺流程. This enables high-quality dissolving pulp production from abundant recycled fibers, overcoming supply limitations of traditional wood-based methods
4Manufacturing precision
If enzymatic treatments are applied to remove hemicelluloses, then pulp quality is improved, but process complexity and cost increase
Solution Approach 1:
The patent applies parameter changes by using chemical extraction parameters (alkaline conditions, temperature, time) to achieve hemicellulose removal替代 enzymatic methods. This chemical approach simplifies the process while maintaining effective hemicellulose removal, reducing process complexity while improving pulp quality for dissolving applications
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 produces dissolving pulps with properties comparable to or superior to commercial reference pulps, suitable for various applications, including regenerated fibers and films, and promotes a sustainable textile industry.
Implementation Method 1
subjecting the fibrous material to an alkaline extraction at a temperature of about 0 to 25 °C, to produce fibres having a reduced content of hemicellulose
Implementation Method 2
subjecting the fibres thus obtained to a bleaching treatment carried out with oxidative chemical reagents in order to reduce the lignin content of the fibres
Data Source
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AI summary
A method of producing dissolving pulp from a recycled fibrous feedstock. The method comprises providing a fibrous material comprising cellulose, lignin and hemicellulose, said fibre source further having a lignin content of 0.1 to 7 % lignin and an ash content of up to 3%;subjecting the fibrour material to an alkaline extraction at a temperature of about0 to 25 º C, to produce fibres having a reduced content of hemicellulose; subjecting the fibres thus obtained to a bleaching treatment carried out with oxidative chemical reagents in order to reduce the lignin content of the fibres; and recovering the fibres thus obtained. By means of the method, dissolving pulp can be produced from recycled paper and cardboard products.