Polysaccharide Fiber Production via Direct Dissolving
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Solution Overview
Problem
Existing methods for producing polysaccharide fibers, such as viscose and lyocell processes, face challenges with the use of hazardous chemicals like carbon disulfide and the need for complex process cycles, which are costly and environmentally detrimental.
Innovation Solution
A direct dissolving process using aqueous sodium hydroxide solution to produce α(1→3)-glucan fibers, with optimized spin bath compositions that vary in sulfuric acid concentration, allowing for improved filament formation and stretchability, and a two-bath system for efficient coagulation and regeneration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If viscose process is used to produce cellulose fibers, then fiber production is achieved, but hazardous chemical carbon disulfide must be used and recovered with great effort
Solution Approach 1:
The patent extracts and eliminates the hazardous carbon disulfide step from the traditional viscose process by using a direct dissolving method with aqueous sodium hydroxide solution, thereby achieving fiber production without the harmful intermediate compounds
Solution Approach 2:
The invention uses a simple, inexpensive aqueous sodium hydroxide solution as the dissolving medium instead of complex and hazardous viscogen systems, making the process more environmentally friendly and easier to handle
2Object-affected harmful factors
If lyocell process with tertiary amine oxide is used, then direct dissolving is achieved, but complex process cycles are required with nearly completely closed cycles causing substance accumulation
Solution Approach 1:
The patent extracts and removes the complex closed-cycle requirement from the lyocell process by using aqueous sodium hydroxide solution, which allows for simpler, more open process cycles without substance accumulation problems
Solution Approach 2:
The invention changes the solvent parameter from tertiary amine oxide to aqueous sodium hydroxide solution, fundamentally altering the process characteristics to enable simpler cycle operations while maintaining direct dissolving capabilities
3Productivity
If standard spin bath is used for fiber spinning, then fiber production is achieved, but filament formation and stretchability are poor
Solution Approach 1:
The patent optimizes the spin bath composition by adjusting sulfuric acid concentration to 200-500 g/l and sodium sulfate to 200-400 g/l, significantly improving filament formation and stretchability compared to standard spin baths
Solution Approach 2:
The invention introduces a two-bath system with different compositions for coagulation and stretching, allowing dynamic optimization of fiber properties at different stages of the spinning 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 process eliminates the need for carbon disulfide and complex cycle closures, offering a safer, more cost-effective, and environmentally friendly method for producing polysaccharide fibers with enhanced properties.
Implementation Method 1
a direct dissolving process based on aqueous sodium hydroxide solution
Implementation Method 2
the spun fiber is subsequently stretched in an acid regeneration bath
Data Source
AI summary
The present invention relates to a direct dissolving process for the production of polysaccharide fibers which contain α(1→3)-glucan as a fiber-forming substance, with aqueous sodium hydroxide solution as a solvent, as well as to the fibers made thereby, and to their use.