Foamed PVC Sheet Weight Reduction via Screening Layer
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Solution Overview
Problem
The high weight and density of traditional PVC floor and wall panels due to mineral fillers result in high transport costs, a significant CO2 footprint, and uncomfortable installation, necessitating a method to reduce weight and density while maintaining a three-dimensional structured top layer.
Innovation Solution
A multilayer PVC sheet material is formed using a foamed polymer mass from a first extruder and an unfoamed polymer mass from a second coextruder, with the coextruded layer acting as a screening layer to prevent reactivation of foaming agents when contacted by a heated structuring roll, ensuring the three-dimensional structure is maintained without additional foaming effects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a high level of mineral filler is used in the carrier material to manufacture PVC panels by extrusion, then the structural integrity and rigidity of the panels are improved, but the weight and density of the sheet material increase significantly
Solution Approach 1:
The patent applies foaming agents to create a porous foam structure within the carrier layer, replacing dense mineral fillers with air-filled voids. This reduces the weight and density of the sheet material while maintaining structural integrity through the cellular foam architecture that provides mechanical strength without the mass of traditional fillers.
Solution Approach 2:
The patent creates a composite material system combining PVC resin with foaming agents to produce a foam-based carrier layer. This composite approach replaces the traditional PVC-mineral filler composite with a PVC-foam composite, achieving weight reduction while preserving necessary mechanical properties through the foam structure.
2Weight of moving object
If a foamed polymer mass is used to reduce weight, then the weight and density of the sheet material are reduced, but the risk of foaming agent reactivation during structuring increases
Solution Approach 1:
The patent introduces an unfoamed polymer mass layer as an intermediary barrier between the heated structuring roll and the foamed carrier layer containing active foaming agents. This intermediate layer prevents thermal energy from reaching the foaming agents during the structuring process, eliminating the risk of reactivation while allowing the foamed carrier to provide weight reduction.
Solution Approach 2:
The patent applies the unfoamed polymer mass layer in advance during the coextrusion process, creating a protective barrier before the structuring step occurs. This preliminary action ensures that when the sheet undergoes heating during structuring, the foaming agents are already protected from thermal activation by the intervening unfoamed layer.
3Reliability
If a screening layer is added to prevent foaming agent reactivation, then the risk of foaming is reduced, but the complexity of the multilayer structure increases
Solution Approach 1:
The patent merges the screening function with the carrier layer itself by using the unfoamed polymer mass as both the screening barrier and part of the carrier structure. This integration eliminates the need for a separate screening layer, reducing overall structural complexity while maintaining the protective function against foaming agent reactivation.
Solution Approach 2:
The unfoamed polymer mass layer serves multiple functions simultaneously: it acts as a screening layer to block thermal energy from reaching foaming agents, provides structural support as part of the carrier, and contributes to the overall mechanical integrity of the sheet. This multi-functionality reduces the need for additional specialized layers.
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 lighter and less dense PVC sheet material with a maintained three-dimensional structured top layer, reducing transport costs and environmental impact while preventing foaming agent reactivation, which would otherwise compromise the structural integrity and appearance of the panels.
Implementation Method 1
a first polymer mass comprising a PVC and a foaming agent is melted under pressure and is forced through an extruder head at a well-defined discharge rate in the form of a foamed plastic strand
Implementation Method 2
at least one roll (structuring roll) is provided with a three-dimensional structure, which owing to rolling in the laminated layers or in the sheet material at high temperature, will transfer this three-dimensional structure permanently in the visible top layer
Implementation Method 3
these also cannot be activated when these come into contact with a heated structuring roll. In this way, this coextruded layer forms a screening layer for the carrying layer that is formed from the foamed PVC material, in which foaming agents are present
Data Source
AI summary
The present invention relates to a method for forming a multilayer plastic sheet material for floor and/or wall panels, wherein a first polymer mass comprising a chemically foamed PVC is melted under pressure and is forced through an extruder head at a well-defined discharge rate as a plastic strand in sheet form that is provided with one or more layers so that a multilayer plastic strand is formed, which is propelled towards two or more rolls of a rolling mill, which processes the multilayer plastic strand to a sheet of a defined thickness and where one of the rolls will apply a three-dimensional structure in the top layer. This sheet will then be led away by a discharge device to a sawing device to be cut off to the desired length and width and finally, in a subsequent production step, as multilayer plank-shaped elements, will be provided with coupling parts on two opposite edges so that several of said plank-shaped elements are couplable together.