Cellulose Nanofiber Compact Manufacturing via Infrared Dehydration

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Solution Overview

Problem

Existing methods for manufacturing cellulose nanofiber compacts often result in products with insufficient strength due to inefficient dehydration and molding processes, leading to potential outflow of nanofibers and uneven drying.

Innovation Solution

A method involving microwave condensation of cellulose nanofiber slurry to form a precursor, followed by infrared heating to promote hydrogen bonding, and subsequent molding with pressurization in a ceramic heating vessel to enhance tensile and bending modulus, while using a porous heating vessel and cellophane to manage water vapor and prevent clogging.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If mechanical pressurization is applied to dehydrate cellulose nanofiber slurry, then dehydration efficiency is improved, but nanofiber outflow occurs reducing product strength

Engineering Contradiction:
Improvedehydration efficiencyVSAvoidcompact strength
Core Design Contradiction:
ProductivityVSStrength

Solution Approach 1:

The patent replaces mechanical pressurization with infrared radiation heating to achieve dehydration. The infrared heater causes water molecules to vibrate and evaporate without applying mechanical pressure, thus preventing nanofiber outflow while maintaining dehydration efficiency. This substitutes a mechanical system with a thermal field system.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent utilizes the phase transition of water from liquid to vapor through infrared heating. The infrared radiation directly heats water molecules in the slurry, causing them to evaporate and leave the nanofiber network intact, thereby achieving dehydration without mechanical compression.

Inventive Principle:
Principle #36Phase transitions

2Loss of time

If conventional heating is used to dry the precursor, then drying occurs, but uneven drying creates paper-like structures reducing strength

Engineering Contradiction:
Improvedrying timeVSAvoiddrying uniformity
Core Design Contradiction:
Loss of timeVSManufacturing precision

Solution Approach 1:

The patent replaces conventional contact heating with infrared radiation heating. The infrared heater emits radiant energy that penetrates and heats the precursor uniformly throughout its volume, causing simultaneous evaporation of water molecules across the entire material. This eliminates the temperature gradients and uneven drying that occur with conventional heating methods.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

3Quantity of substance

If high pressure is applied during molding, then compact density is improved, but nanofiber network structure is damaged reducing strength

Engineering Contradiction:
Improvecompact densityVSAvoidnanofiber network integrity
Core Design Contradiction:
Quantity of substanceVSStrength

Solution Approach 1:

The patent replaces mechanical pressurization during the dehydration and drying stages with infrared radiation heating. This thermal field approach achieves water removal and densification without applying high mechanical pressure that would damage the nanofiber network. The nanofibers bond through hydrogen bonds formed during infrared heating rather than through mechanical compression.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

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

The method achieves a cellulose nanofiber compact with improved strength and uniform drying, preventing the formation of paper-like structures and enhancing tensile and bending elasticity modulus.

Implementation Method 1

heating of the first precursor supported in the heating vessel is implemented by irradiation of infrared rays

Methodology Applied
Scientific EffectInfrared radiation: Infrared Radiation

Implementation Method 2

by heating the first precursor with infrared rays, there can be obtained a second precursor with the hydrogen bond promoted

Methodology Applied
Scientific EffectHydrogen bond: Chemical Bonding

Implementation Method 3

a condensing step of condensing the cellulose nanofiber containing slurry by microwave heating

Methodology Applied
Scientific EffectMicrowave heating: Microwave Radiation

Implementation Method 4

the heating vessel is constituted of a porous body defining therein many pores that allow passage of water vapor

Methodology Applied
Scientific EffectPermeation: Permeation

Data Source

PatentEP3771773B1Method of manufacturing cellulose nanofiber compact
Publication Date: 2023.01.11 HOSIDEN CORP
  • EP3771773B1 patent drawingFigure 1~3
  • EP3771773B1 patent drawingFigure 4~6
  • EP3771773B1 patent drawingFigure 7~8

AI summary

A method of manufacturing a cellulose nanofiber compact (13) includes a supporting step of supporting a plate-like first precursor (11) containing cellulose nanofibers in a heating vessel (30), a preliminary molding step of heating the first precursor (11) supported in the heating vessel (30) with infrared rays to obtain a plate-like second precursor (12) and a molding step of molding the second precursor (12), with heating and pressurizing the second precursor (12) in a mold (50).