Cellulose Shaped Articles via Ionic Liquid Cosolvent Dope
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Solution Overview
Problem
Traditional methods for producing cellulose fibers, such as the viscose process, face challenges including high solvent costs, high ionic strength, and the need for inert environments due to the use of alkali and carbon disulfide solvents, while ionic liquid-based solutions often result in high viscosity and high ionic liquid usage, limiting their industrial applicability.
Innovation Solution
A process using a dope comprising an ionic liquid and a polar aprotic cosolvent, with a temperature of 70°C or lower, and a composition of 5-15 wt.% cellulose, where the ionic liquid constitutes 20-50% of the dope by weight, allowing for the dissolution of cellulose in conventional equipment and enabling the use of less refined pulps without the need for inert atmospheres.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If ionic liquid-based dopes are used to dissolve cellulose, then cellulose solubility is improved, but viscosity increases significantly
Solution Approach 1:
The patent changes the chemical composition parameters of the dope by introducing a polar aprotic cosolvent (such as DMSO, DMAc, or DMF) in combination with ionic liquid. This parameter change modifies the solvent system's properties to achieve lower viscosity while maintaining cellulose solubility. The specific ratio of ionic liquid (20-50 wt%) to cosolvent is optimized to balance solubility and viscosity requirements.
2Stability of the object's composition
If high proportions of ionic liquid are used in the dope, then cellulose dissolution is enhanced, but production cost increases
Solution Approach 1:
The patent optimizes the concentration parameter of ionic liquid in the dope to range from 20-50 wt%, finding the optimal balance between dissolution effectiveness and cost. By not using pure ionic liquid or excessively high concentrations, the process reduces material costs while maintaining adequate cellulose dissolution. The cosolvent acts as a cost-effective supplement that enhances the ionic liquid's performance.
Solution Approach 2:
The patent creates a composite solvent system combining ionic liquid and polar aprotic cosolvent. This composite approach leverages the strengths of both components: the ionic liquid provides excellent cellulose dissolution capability, while the cosolvent reduces viscosity and cost. The synergistic interaction between the two solvents achieves better overall performance than either component alone.
3Ease of manufacture
If traditional solvents like alkali and carbon disulfide are used, then cellulose fiber production is achieved, but environmental and safety hazards increase
Solution Approach 1:
The patent fundamentally changes the chemical nature of the solvent system from traditional toxic solvents (alkali and carbon disulfide) to a greener alternative comprising ionic liquid and polar aprotic cosolvent. This parameter change in solvent composition eliminates the need for inert atmospheres and reduces environmental hazards while maintaining cellulose dissolution and fiber production capabilities.
4Productivity
If dissolution temperature is increased to improve cellulose dissolution rate, then dissolution speed increases, but energy consumption increases
Solution Approach 1:
The patent changes the chemical composition of the solvent system to include ionic liquid and polar aprotic cosolvent, which have superior cellulose dissolution capabilities. This compositional parameter change allows for effective cellulose dissolution at lower temperatures (avoiding the need for excessive thermal energy input) while maintaining high dissolution rates. The optimized solvent composition reduces the activation energy required for cellulose dissolution.
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 reduces thermal energy input, lowers viscosity, and allows for the efficient production of cellulose fibers using conventional machinery, while being stable and cost-effective, enabling the production of cellulose articles with controlled density and mechanical properties.
Implementation Method 1
cellulose is at least partly dissolved at a temperature of 70°C or lower in a dope comprising an ionic liquid and a cosolvent
Data Source
Figure 1~2
Figure 3
AI summary
The present invention provides a process for producing cellulose shaped articles in which a) cellulose is at least partly dissolved at a temperature of about 100°C or lower in a dope comprising an ionic liquid and a cosolvent to form a cellulose solution, wherein said cosolvent comprises a polar aprotic component, and b) cellulose shaped articles are cast from the cellulose solution.