Ionic Liquid Solvent System for Regenerating Cellulose Fibres
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Solution Overview
Problem
Current methods for regenerating cellulose and starch derivatives face challenges such as high waste production, unwanted emissions, and energy-intensive solvent recovery due to the use of conventional solvents, particularly when water content exceeds 5% by weight, which complicates the process and increases costs.
Innovation Solution
A solution system based on a molten ionic liquid containing a protic solvent, such as water or alcohols, where the protic solvent is present in amounts greater than 5% by weight, allowing for coagulation in a non-solvent miscible with the ionic liquid, reducing energy requirements and environmental impact.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If water is used as a protic solvent in amounts greater than 5% by weight in the solution system, then the regeneration process becomes more economical and environmentally friendly, but the solvent recovery becomes more complex and energy-intensive
Solution Approach 1:
The patent changes the parameter of water content in the solution system from the conventional limit of <5% to >5% by weight. This parameter change enables the use of water as a protic solvent that simplifies the regeneration process and makes it more economical, while the ionic liquid's unique properties allow for efficient solvent recovery despite the higher water content
Solution Approach 2:
The patent employs water, a cheap and environmentally friendly protic solvent, in amounts greater than 5% by weight in the solution system. This replaces conventional organic solvents and simplifies the regeneration process, making it more economical and environmentally friendly despite the trade-off in solvent recovery complexity
2Ease of manufacture
If conventional solvents are used for cellulose regeneration, then the process is well-established, but large amounts of salts and sulfur-containing exhaust gases are produced
Solution Approach 1:
The patent changes the chemical composition parameter of the solution system by using ionic liquids combined with protic solvents (water or alcohols) in amounts greater than 5% by weight. This replaces conventional viscose process solvents, eliminating the production of large amounts of salts and sulfur-containing exhaust gases while maintaining an established regeneration approach
Solution Approach 2:
The patent converts the previously harmful effect of high water content (>5% by weight) in ionic liquid solutions, which was considered a disadvantage requiring complex separation, into a beneficial feature that simplifies the regeneration process and eliminates harmful waste products when combined with the specific ionic liquid system
3Loss of substance
If NMMO is used as a solvent for direct cellulose solution, then waste levels are reduced, but the solution window is narrow and system-related fibrillation occurs
Solution Approach 1:
The patent creates a composite solvent system combining ionic liquids with protic solvents (water or alcohols) in amounts greater than 5% by weight. This composite system overcomes the narrow solution window of NMMO by providing a broader range of soluble conditions while maintaining low waste levels and preventing system-related fibrillation
Solution Approach 2:
The patent changes the solvent composition parameter from pure NMMO to a mixed system of ionic liquid and protic solvent (>5% by weight). This parameter change expands the solution window and improves adaptability while maintaining the environmental benefits of reduced waste production
4Ease of manufacture
If imidazole-based ionic liquids are used for direct cellulose solution, then water-free conditions improve dissolution, but separation and recovery becomes technically difficult and extremely energy-intensive
Solution Approach 1:
The patent introduces protic solvents (water or alcohols) in amounts greater than 5% by weight as an intermediary component in the ionic liquid system. This intermediary enables the ionic liquid to maintain its dissolution efficiency for cellulose and starch derivatives while facilitating easier separation and recovery, reducing the technical difficulty and energy intensity of the separation process
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
This approach enables economical and environmentally friendly regeneration of cellulose and starch derivatives by allowing water to remain in the solution system, simplifying solvent recovery and reducing energy expenditure, while maintaining product quality and structural integrity.
Implementation Method 1
a solution system containing starch, cellulose and/or derivatives of starch and cellulose, the solution system being based on a molten ionic liquid
Implementation Method 2
the solution system is transferred to a coagulation medium in which there is a solvent which does not dissolve the starch, cellulose and/or derivatives of starch and cellulose
Data Source
AI summary
A solvent system for biopolymers in the form of carbohydrates which is based on a molten ionic liquid, with additives being present in the solvent system if appropriate, is described. This solvent system comprises a protic solvent or a mixture of a plurality of protic solvents, and if the protic solvent is water alone, this is present in the solvent system in an amount of more than about 5% by weight. Carbohydrates can be incorporated into the solvent system, in particular in the form of starch, cellulose and derivatives thereof, and the solvent system can then be employed for regenerating the carbohydrates dissolved therein. In addition, a particularly advantageous method of producing the solvent system containing the carbohydrates and for producing regenerated carbohydrates, in particular in the form of regenerated cellulose fibres, is described. The invention accordingly also provides such spinning fibres which are nonfibrillating. The invention offers, in particular, economic advantages over the systems of the prior art.