Cellulose-Fiber Flat Structure Production Using Disposable Polyethylene Foam
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Solution Overview
Problem
Existing methods for producing cellulose-fiber flat structures struggle to efficiently recover fine cellulose fibers with nano-level diameters and achieve favorable surface textures, leading to limitations in applications such as display substrates due to issues with filter materials like polytetrafluoroethylene being expensive and impractical for large-scale use, and conventional filter materials failing to prevent surface texture transfer.
Innovation Solution
A method involving the use of a filter material with specific properties, including water permeability not exceeding 100 ml/m²·s and an initial tensile modulus of 20 MPa or greater, formed from synthetic or natural fibers, subjected to heat and pressure treatment, and used to filter a dispersion of cellulose fibers with diameters between 4 to 100 nm, followed by a fibrillation treatment to produce a cellulose-fiber flat structure with improved surface texture.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If PTFE porous film is used for filtering cellulose fiber dispersion, then fine cellulose fibers can be recovered, but surface texture is transferred to the obtained structure and optical properties fluctuate
Solution Approach 1:
The patent replaces expensive PTFE porous films with inexpensive porous polyethylene foam that can be easily replaced. The foam is fixed to the support material and serves as a disposable filter that can be changed when its surface texture transfers to the cellulose structure, ensuring consistent optical properties without the cost and complexity of PTFE films.
Solution Approach 2:
The patent introduces porous polyethylene foam as an intermediary filtering layer between the support material and the cellulose fiber dispersion. This foam layer acts as a mediator that prevents direct contact between the support material surface and the cellulose, thereby preventing surface texture transfer while still allowing fine fiber recovery.
2Manufacturing precision
If PTFE filter material is used for filtering, then fine cellulose fibers can be recovered, but the material is expensive and impractical for large-scale use
Solution Approach 1:
The patent substitutes expensive PTFE filter material with inexpensive porous polyethylene foam that can be easily manufactured and replaced. The foam's low cost makes it economically viable for large-scale production while maintaining adequate filtering performance for fine cellulose fiber recovery.
Solution Approach 2:
The patent changes the material parameter from PTFE to porous polyethylene foam, altering the filtering mechanism while maintaining effectiveness. The foam's pore structure provides sufficient filtration capability for nanometer-level cellulose fibers at a fraction of the cost of PTFE materials.
3Ease of manufacture
If conventional filter fabric is used for filtering cellulose dispersion, then the process is simple, but the majority of fine cellulose fibers remain in the filtrate and cannot be efficiently recovered
Solution Approach 1:
The patent employs porous polyethylene foam with specific pore size and structure that enables efficient capture of fine cellulose fibers while maintaining a simple filtering process. The foam's porous structure provides high surface area and appropriate pore dimensions to trap nanometer-level fibers that conventional fabrics miss, significantly improving recovery efficiency.
Solution Approach 2:
The patent creates a composite filtering system by fixing porous polyethylene foam to a support material. This composite structure combines the mechanical support of the base material with the fine filtration capabilities of the foam, achieving both simple processing and high fiber recovery efficiency.
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 efficiently recovers fine cellulose fibers, produces a cellulose-fiber flat structure with favorable surface texture, and enables continuous processing, enhancing its applicability in display and other applications by preventing surface texture transfer and reducing material costs.
Implementation Method 1
filtering a fine cellulose-fiber dispersion containing fine cellulose fibers having an average fiber diameter of 4 to 100 nm, using a filter material
Implementation Method 2
formed from at least one type of fiber selected from the group consisting of synthetic resin fibers, regenerated fibers and natural fibers, wherein the filter material is obtained by subjecting a fabric formed using a fiber having an average thread thickness of 1 to 5 d/f to a heat and pressure treatment
Data Source
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AI summary
The present invention relates to a method of producing a cellulose-fiber flat structure, the method including obtaining a cellulose-fiber flat structure by filtering a fine cellulose-fiber dispersion containing fine cellulose fibers having an average fiber diameter of 4 to 100 nm, using a filter material having a water permeability of not more than 100 ml/m2·s and an initial tensile modulus of 20 MPa or greater. The present invention is able to produce a cellulose-fiber flat structure by efficiently recovering fine cellulose fibers from a dispersion containing fine cellulose fibers having an average fiber diameter at the nano level. The method of producing a cellulose-fiber flat structure can also be applied to a continuous process.