Laminated Sheet Production via Segmented Pressing and Coating
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Solution Overview
Problem
The production of high-pressure laminates is costly due to the need for expensive re-cooling presses that endure high thermal loads and are prone to bursting from excessive steam pressure, with melamine resins exhibiting thermal instability leading to discolouration and limited pressing temperatures.
Innovation Solution
A two-stage process where cellulose fiber webs are pressed to form a base plate with increased pressure and temperature, followed by separate coating, allowing for higher pressing temperatures and reduced pressing time, and incorporating a porous vapor-permeable layer to manage internal vapor pressure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If re-cooling presses are used to cool panels before opening to reduce vapor pressure, then panel quality is improved, but press cost and maintenance requirements increase due to high thermal loads
Solution Approach 1:
The pressing process is divided into two independent stages: first pressing at high temperature to form the base plate, then cooling and coating separately. This segmentation eliminates the need for re-cooling presses while maintaining panel quality through controlled cooling after pressing.
Solution Approach 2:
The base plate is pressed and cooled completely before the coating application step. This preliminary completion of the pressing and cooling sequence eliminates the need for complex re-cooling mechanisms during the coating process, reducing press maintenance requirements.
2Productivity
If high pressing temperatures are used to reduce pressing time, then productivity is improved, but melamine resin discolouration occurs
Solution Approach 1:
The process separates the high-temperature pressing stage (where phenolic resin provides thermal stability) from the coating stage (where melamine resin is applied to the cooled base plate). This allows high pressing temperatures without discolouration since the melamine coating is applied after cooling.
Solution Approach 2:
The base plate is pressed at high temperature to achieve rapid production, then completely cooled before the melamine coating is applied. This preliminary cooling prevents thermal damage to the melamine resin while maintaining high productivity during the pressing stage.
3Reliability
If a porous vapor-permeable layer is added to manage steam pressure, then press bursting is prevented, but device complexity increases
Solution Approach 1:
A porous vapor-permeable layer is introduced between the layers to be pressed. This layer allows steam to escape during pressing, preventing excessive vapor pressure that could cause press bursting, while adding minimal structural complexity.
4Productivity
If coating is applied during the pressing process, then production steps are reduced, but manufacturing precision and quality control are compromised
Solution Approach 1:
The process is segmented into distinct stages: first the base plate is pressed and cooled, then the coating is applied separately. This segmentation allows for better quality control and manufacturing precision while maintaining productivity through efficient process integration.
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 reduces production costs, eliminates the need for high-maintenance press plates, and enables the production of thicker, longer laminates with improved adhesion and surface quality, facilitating just-in-time delivery and increased flexibility in coating options.
Implementation Method 1
providing a porous, vapor-permeable layer on the side of a stack of layers to be pressed that faces away from the decoration
Implementation Method 2
feeding the layering into a hot press and pressing the layering while increasing the pressure and temperature into a base plate
Implementation Method 3
a plurality of impregnated, uncompressed cellulosic fiber webs... pressing the layering while increasing the pressure and temperature
Data Source
Figure 1
AI summary
The invention relates to a method for producing a laminated sheet (1), wherein the following steps are carried out successively: providing a number of cellulose fibre webs (4) provided with an impregnation; forming layers, in which the cellulose fibre webs provided with impregnation are arranged one above the other; introducing the layers into a hot press; pressing the layers by increasing the temperature and pressure to give a base sheet; removing the base sheet from the hot press and coating the base sheet. Such a method guarantees an optimal quality with reduced pressing times despite the lack of use of a back cooling press. The invention further relates to a laminated sheet produced by said method.