Lyocell Fiber Crosslinking Before Cutting
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Solution Overview
Problem
Existing methods for producing crosslinked lyocell staple fibers face challenges related to chemical consumption and processing efficiency, particularly in terms of energy usage and fiber properties such as strength and crimp.
Innovation Solution
A method involving the extrusion of cellulose filaments from a solution in an organic solvent, followed by washing, crosslinking with a crosslinking agent, and then cutting into staple fibers, which are formed into a nonwoven fleece and pressed to achieve a permanent crimp.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If crosslinking is performed on staple fibers after cutting (fleece aftertreatment), then fiber strength is improved, but energy consumption and chemical usage increase
Solution Approach 1:
The patent applies preliminary action by performing crosslinking treatment on continuous filaments before cutting them into staple fibers. The crosslinking agent is applied and reaction conditions are established while the cellulose is in the filament form, allowing the crosslinking reaction to proceed before the material is divided into staples. This preliminary timing of the crosslinking step reduces subsequent processing energy and chemical requirements while achieving the desired fiber strength improvement.
2Strength
If crosslinking is performed on staple fibers after cutting (fleece aftertreatment), then fiber strength is improved, but chemical consumption increases
Solution Approach 1:
The patent applies preliminary action by performing crosslinking treatment on continuous filaments before cutting them into staple fibers. The crosslinking agent is applied and reaction conditions are established while the cellulose is in the filament form, allowing the crosslinking reaction to proceed before the material is divided into staples. This preliminary timing of the crosslinking step reduces subsequent processing energy and chemical requirements while achieving the desired fiber strength improvement.
3Productivity
If continuous filaments are cut into staple fibers before crosslinking, then processing efficiency is improved, but fiber strength and crimp properties deteriorate
Solution Approach 1:
The patent applies preliminary action by performing crosslinking treatment on continuous filaments before cutting them into staple fibers. The crosslinking agent is applied and reaction conditions are established while the cellulose is in the filament form, allowing the crosslinking reaction to proceed before the material is divided into staples. This preliminary timing of the crosslinking step reduces subsequent processing energy and chemical requirements while achieving the desired fiber strength improvement.
4Shape
If fleece aftertreatment is used for crimping, then permanent crimp is achieved, but energy and chemical usage increase
Solution Approach 1:
The patent merges multiple processing functions into the continuous filament stage before cutting. The crosslinking treatment and crimping operations are combined and performed while the cellulose is in the filament form, allowing both the permanent crimp shape and crosslinked strength properties to be established simultaneously before the material is divided into staple fibers, thereby reducing total energy and chemical consumption.
Solution Approach 2:
The patent applies preliminary action by performing crosslinking treatment on continuous filaments before cutting them into staple fibers. The crosslinking agent is applied and reaction conditions are established while the cellulose is in the filament form, allowing the crosslinking reaction to proceed before the material is divided into staples. This preliminary timing of the crosslinking step reduces subsequent processing energy and chemical requirements while achieving the desired fiber strength improvement.
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 method results in significant energy and chemical savings, improved fiber strength, and a permanent crimp, while maintaining a low coefficient of variation in wet abrasion resistance, outperforming conventional fleece aftertreatment methods.
Implementation Method 1
a) extruding filaments from a solution of cellulose in an organic solvent
Implementation Method 2
b) precipitating the cellulose for the formation of continuous cellulose filaments
Implementation Method 3
d) contacting the cellulose filaments with a crosslinking agent e) reacting the cellulose filaments with the crosslinking agent in a reaction chamber
Data Source
AI summary
The invention relates to a method for the production of lyocell staple fibers, comprising the steps in the following order: a) extruding filaments from a solution of cellulose in an organic solvent; b) precipitating the cellulose for the formation of continuous cellulose filaments; c) washing the cellulose filaments; d) contacting the cellulose filaments with a crosslinking agent; e) reacting the cellulose filaments with the crosslinking agent in a reaction chamber; f) washing the treated cellulose filaments; g) cutting the washed cellulose filaments into staple fibers; h) forming a nonwoven fleece from the staple fibers and pressing the nonwoven fleece; and i) finishing the nonwoven fleece and pressing the nonwoven fleece.