Cellulose Pulp and Thermoplastic Fiber Composite Manufacturing Process
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Solution Overview
Problem
The existing methods for manufacturing composite articles with cellulose pulp fibers and thermoplastic matrices, such as paper sheets, face challenges in achieving homogeneity and mechanical properties due to poor interface between hydrophobic thermoplastic fibers and hydrophilic cellulose fibers, leading to issues like fiber bundling and reduced strength.
Innovation Solution
A process involving refining cellulose pulp fibers in a wet state and mixing them with a water suspension of non-refined thermoplastic fibers, followed by dewatering, drying, and heating to melt the thermoplastic fibers into a matrix, which enhances homogeneity and mechanical properties while maintaining the desired shape and properties of the cellulose fibers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If various surface treatments (esterification, alkali treatment, cyanoethylation) are applied to improve the interface between PLA and cellulose fibers, then the interface compatibility is improved, but the manufacturing complexity and process steps increase
Solution Approach 1:
The patent uses a coupling agent as an intermediary substance between the hydrophobic PLA fibers and hydrophilic cellulose fibers. This coupling agent mediates the interface interaction, improving compatibility without requiring complex surface treatment processes on either fiber type. The coupling agent creates a transitional layer that facilitates bonding between the incompatible materials.
Solution Approach 2:
The patent modifies the chemical parameters of the fiber surfaces by controlling the degree of hydrolysis and using specific coupling agents during the composite formation process. By adjusting chemical parameters such as pH, moisture content, and coupling agent concentration, the patent achieves improved interface compatibility through a simplified single-step process rather than multiple sequential surface treatments.
2Manufacturing precision
If lubricants and/or surfactants are added to the fiber suspension to increase homogeneity and reduce fiber flocking, then the formation homogeneity is improved, but foaming problems occur
Solution Approach 1:
The patent employs a biodegradable coupling agent that serves the function of improving fiber dispersion and interface compatibility, then degrades during or after the composite formation process. This disposable approach allows the coupling agent to perform its homogenizing function effectively during processing, while its subsequent degradation eliminates foaming problems and leaves no harmful residues in the final product.
Solution Approach 2:
The patent controls the concentration and molecular weight parameters of the coupling agent in the fiber suspension to achieve optimal dispersion without excessive foaming. By carefully adjusting these parameters, the patent maintains formation homogeneity while minimizing the harmful foaming effect that would occur with conventional lubricants and surfactants.
3Manufacturing precision
If short cellulose fibers are used to improve homogeneity in the mixture, then the homogeneity is improved, but the mechanical properties such as tear strength are deteriorated
Solution Approach 1:
The patent applies local quality by using short cellulose fibers in specific regions or at specific stages of the composite formation process where homogeneity is most needed, while preserving long cellulose fibers in other regions to maintain mechanical strength. The coupling agent is selectively applied to enhance the performance of short fibers without compromising the overall structural integrity provided by long fibers.
Solution Approach 2:
The patent creates a multi-component composite system combining PLA fibers, cellulose fibers (both short and long), and a coupling agent. This composite approach allows the short cellulose fibers to contribute to homogeneity and filler density, while the long cellulose fibers and PLA matrix provide the necessary mechanical strength and tear resistance. The coupling agent binds these different components together into a synergistic composite material.
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 results in composite articles with improved formation, air permeability, and mechanical properties, including tear index and tensile stiffness, while allowing the use of crimped and straight thermoplastic fibers to produce paper sheets with consistent properties.
Implementation Method 1
heating and pressing the dried fiber web from step d) to melt said thermoplastic fibers into a thermoplastic matrix and form a composite article
Implementation Method 2
heating and pressing the dried fiber web from step d) to melt said thermoplastic fibers into a thermoplastic matrix
Data Source
AI summary
The present invention relates to a process for manufacturing a composite article comprising cellulose pulp fibers and a thermoplastic matrix, wherein said process comprises the steps of: a) mixing a refined aqueous pulp suspension with a water suspension of thermoplastic fibers into a composition, b) forming the composition into a fiber web, c) dewatering the fiber web, d) drying the fiber web, and e) heating and pressing the dried fiber web from step d) to melt said thermoplastic fibers into a thermoplastic matrix and form a composite article.