Multi-Layer Floor Panel Pressing for Fast Assembly and Strong Bonding
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Solution Overview
Problem
The gluing of composite panels with high PVC content and wooden veneers obtained through chipless machining is hindered by low surface energy, temperature sensitivity, non-homogeneous surface structure, and variable hygroscopic and anisotropic properties, leading to inefficient manufacturing processes and increased investment costs due to the need for multiple gluing stations.
Innovation Solution
A two-stage pressing process is employed, where a core composite layer made of mineral raw materials and polymers is activated and glued with a top layer of solid wood sheets using a reactive polyurethane adhesive, with preliminary pressing to secure layer positioning and main pressing to achieve durable adhesion, ensuring efficient production line throughput.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If adhesives with good bond quality are used, then adhesive bond strength is improved, but open time becomes excessively short, leading to difficulties in assembling wooden layer pieces quickly
Solution Approach 1:
The pressing process is divided into two distinct stages: preliminary pressing (5-50 seconds) to secure layer positioning and main pressing (300+ seconds) to achieve durable adhesive bond. This segmentation allows the adhesive to remain open for assembly while still achieving strong bonding, resolving the contradiction between bond strength and open time.
Solution Approach 2:
Preliminary pressing is performed first to secure the layer positioning and prevent movement during assembly. This preliminary action enables the assembly process to proceed quickly without compromising the subsequent main pressing that achieves the durable adhesive bond.
2Loss of time
If adhesives with long open times are used, then assembly time is improved, but pressing time must be increased, leading to lower manufacturing process efficiency
Solution Approach 1:
The pressing process is segmented into preliminary pressing (5-50 seconds) for positioning and main pressing (300+ seconds) for bonding. This allows long open time for assembly while maintaining high productivity through efficient pressing stages.
Solution Approach 2:
Preliminary pressing secures layer positioning quickly, enabling assembly to proceed without delaying the main pressing stage that achieves durable bonding. This preliminary action resolves the contradiction between assembly time and manufacturing efficiency.
3Reliability
If multiple gluing stations are used to handle variable properties of chipless machined wood, then gluing quality is improved, but investment outlays increase
Solution Approach 1:
The invention changes the adhesive parameters by using reactive polyurethane adhesive with specific reactivity characteristics and open time properties. This allows a single gluing station to handle the variable properties of chipless machined wood by controlling the adhesive's chemical characteristics rather than requiring multiple stations with different parameters.
Solution Approach 2:
The reactive polyurethane adhesive acts as an intermediary that bridges the gap between the composite core layer and wooden veneer layers. Its specific chemical properties enable reliable bonding despite the non-homogeneous surface structure and variable hygroscopic properties of the wood, eliminating the need for multiple gluing stations.
4Productivity
If hot pressing is used to reduce pressing time, then productivity is improved, but adhesive binding strength decreases
Solution Approach 1:
The invention changes the adhesive type to reactive polyurethane with specific reactivity characteristics, allowing cold pressing to achieve strong bonding. This parameter change in adhesive chemistry enables both short pressing time (5-50 seconds preliminary + 300+ seconds main) and high binding strength, eliminating the need for hot pressing.
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 maintains production line capacity and efficiency by securing layer positioning and achieving durable adhesive bonds, enhancing dimensional stability and moisture resistance of the panels.
Implementation Method 1
a layer of adhesive is applied to the core composite layer, a composition of solid wood sheets intended for the top layer is provided, where each of the sheets is obtained by way of chipless machining and drying, after which the previously prepared composition of solid wood sheets constituting the top layer is applied onto the applied layer of adhesive within an open time shorter than 40 seconds
Implementation Method 2
the multi-layer panel prepared in the stage S5 is subjected to the first pressing stage, being preliminary pressing, after which numerous such pressed floor panels are stacked, and then the second stage of pressing this stack of preliminary pressed floor panels is implemented, as the main pressing
Data Source
AI summary
In a first pressing stage, constituting preliminary pressing, glued layers forming a single multi-layer floor panel (1) are pressed for a time between 5 and 50 seconds, until a physical, local joining of the layers is obtained allowing determination of the position of the sheets of solid wood constituting a top layer (4) being placed on a core composite layer (2) covered with an adhesive. In the next stage, a stack is formed from numerous floor panels (1) thus pressed, after which the said stack of preliminarily pressed floor panels (1) is subjected to pressing, constituting main pressing, for a time longer than 300 seconds, until the adhesive bond of the required durability and strength is obtained, wherein the adhesive (3) applied to the core composite layer (2) is a hot-melt polyurethane adhesive.