Lignocellulose Board Hardening via High-Frequency Field
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Solution Overview
Problem
Existing processes for producing lignocellulose-based boards require additional compaction steps in heated presses after high-frequency preheating, which is inefficient and costly.
Innovation Solution
A process involving layer-by-layer scattering and compaction of lignocellulose materials, followed by the application of a high-frequency electrical field for thermal hardening, eliminating the need for further compaction steps in heated presses by achieving adequate strength and density within the board.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If high-frequency preheating is used for lignocellulose mats, then heating efficiency is improved, but additional compaction steps in heated presses are required
Solution Approach 1:
The patent combines the heating function and compaction function into a single device by integrating high-frequency heating elements directly into the compaction press. This allows simultaneous heating and compaction of lignocellulose mats, eliminating the need for separate heating and compaction steps while maintaining high heating efficiency.
Solution Approach 2:
The compaction press is designed to perform multiple functions: mechanical compaction, high-frequency heating, and binder curing. By making the press multi-functional, the process complexity is reduced as one device replaces what would otherwise require multiple separate equipment units.
2Manufacturing precision
If additional compaction steps in heated presses are used, then final board density is improved, but production time and cost increase
Solution Approach 1:
The patent merges the density-enhancement function into the single compaction press operation by applying high-frequency heating during compaction. This simultaneous heating and compaction achieves the required board density in one step rather than requiring multiple sequential operations.
Solution Approach 2:
The high-frequency heating is applied during the compaction process itself, preparing the material in advance for final densification. This preliminary thermal preparation enables the compaction press to achieve optimal density without requiring subsequent additional heating or treatment steps.
3Strength
If high-frequency heating is applied during compaction, then thermal hardening is achieved, but equipment complexity increases
Solution Approach 1:
The patent integrates high-frequency heating elements within the compaction press structure, merging the thermal hardening function with the mechanical compaction function. This allows binder curing to occur during the compaction process itself, achieving strength development without requiring separate equipment.
Solution Approach 2:
The compaction press serves as an intermediary device that facilitates both mechanical compression and thermal treatment. By using the press as a multi-functional intermediary, the system achieves thermal hardening while avoiding the need for additional specialized equipment.
4Manufacturing precision
If multiple processing steps are used, then product quality is improved, but manufacturing cost increases
Solution Approach 1:
The patent combines multiple quality-enhancing processes (compaction, heating, binder curing) into a single integrated operation in the compaction press. This reduces the number of processing steps required while maintaining or improving product quality, thereby lowering manufacturing costs.
Solution Approach 2:
By making the compaction press a multi-functional device that performs compaction, heating, and curing simultaneously, the patent reduces the total number of equipment units and process steps needed. This multi-functionality maintains product quality while reducing manufacturing complexity and cost.
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 process achieves rapid and efficient thermal hardening of lignocellulose materials, reducing production costs and improving the strength and density of the final product without the need for additional compaction steps.
Implementation Method 1
application of a high-frequency electrical field during and/or after the compaction and thermal hardening of the binder(s)
Data Source
AI summary
The present invention relates to a process for the batchwise or continuous, preferably continuous production of single-layer lignocellulose-based boards or of multilayer lignocellulose-based boards with a core and with at least one upper and one lower outer layer,comprising the following steps:a) mixing of the components of the individual layer(s),b) layer-by-layer scattering of the mixtures to give a mat,c) compaction after the scattering of the individual layer(s),d) application of a high-frequency electrical field, during and/or after the compaction and thermal hardening of the binder(s),e) then optionally hot pressing, andf) cooling the lignocellulose material,where, in step a),for the core or the single layer, the lignocellulose particles A) [component A)] are mixed withB) from 0 to 25% by weight of expanded plastics particles with bulk density in the range from 10 to 150 kg/m3 [component B)],C) from 1 to 15% by weight of one or more binders selected from the group consisting of aminoplastic resin and organic isocyanate having at least two isocyanate groups [component C)],D) from 0 to 3% by weight of ammonium salts [component D)],E) from 0 to 5% by weight of additives [component E)] andF) from 0.1 to 3% by weight of alkali metal salts or alkaline earth metal salts from the group of the sulfates, nitrates, halides and mixtures of these [component F)],and optionally for the outer layers, the lignocellulose particles G) [component G)] are mixed withH) from 1 to 15% by weight of one or more binders selected from the group consisting of aminoplastic resin and organic isocyanate having at least two isocyanate groups [component H)],I) from 0 to 2% by weight of ammonium salts [component I)],J) from 0 to 5% by weight of additives [component J)] andK) from 0.1 to 3% by weight of alkali metal salts or alkaline earth metal salts from the group of the sulfates, nitrates, halides and mixtures of these [component K)],wherein at the juncture Z the temperature of the layer of the core or of the single layer is more than 90° C., and this temperature is reached in less than 40 s/mm·d after the application of the high-frequency electrical field, where d is the thickness of the sheet of lignocellulose material at the juncture Z.