Multiwall Polymer Sheet With Non-Uniform Cell Density
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Solution Overview
Problem
There is a continuous demand for polymer sheeting with enhanced insulative properties and structural performance without increasing weight or thickness, while maintaining existing benefits such as impact resistance and reduced maintenance costs.
Innovation Solution
The development of multiwall polymer sheets with non-intersecting polymer walls and transverse layers that form cells with non-uniform cell density, featuring a cell size gradient and micro-features, which are produced via extrusion to achieve improved insulative and structural performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If the thickness of polymer sheeting is increased to improve insulative properties, then insulative performance is improved, but weight and structural load increase
Solution Approach 1:
The polymer sheet is divided into multiple walls forming a multiwall structure with cells between them. This segmentation creates air gaps that provide thermal insulation without requiring increased thickness or weight, directly resolving the contradiction between insulative performance and weight.
Solution Approach 2:
The multiwall structure inherently creates a porous configuration with cells containing air or gas. This porous architecture provides thermal insulation through the trapped gas layers while maintaining low overall density and weight, addressing the insulative properties versus weight contradiction.
2Loss of energy
If the thickness of polymer sheeting is increased to improve insulative properties, then insulative performance is improved, but the structural element becomes thicker
Solution Approach 1:
The sheet is segmented into multiple walls forming cells, creating insulating air gaps within a compact thickness. This allows achieving high insulative performance (U-value less than 1.2 W/m2K) without increasing the overall thickness of the structural element.
Solution Approach 2:
The insulation mechanism transitions from relying on thickness to relying on the three-dimensional cell structure with multiple walls. The insulative performance is achieved through the spatial arrangement of walls and cells rather than simply increasing the distance between outer surfaces.
3Loss of energy
If the cell density is made non-uniform with a cell size gradient, then insulative properties are enhanced, but manufacturing complexity increases
Solution Approach 1:
The patent implements non-uniform cell density with a cell size gradient where cell dimensions vary across different regions of the sheet. This local variation in cell size optimizes insulative properties in different areas while the gradient structure can be integrated into the extrusion process, balancing performance enhancement with manufacturing feasibility.
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 multiwall sheets demonstrate a greater than 20% improvement in insulative properties and a greater than 100% improvement in structural performance, with a U-value of less than 1.2 W/m2K and stiffness of over 4,000 N/mm, while maintaining a nominal volume density and thickness.
Implementation Method 1
one of the most significant advantages of polymer sheeting is that it provides improved insulative properties compared to glass
Implementation Method 2
The multiwall sheet can be formed via extrusion
Data Source
AI summary
In one embodiment, a multiwall sheet comprises: non-intersecting polymer walls comprising outer layers and transverse layers. The transverse layers intersect the walls to form cells. The multiwall sheet has a non-uniform cell density. In another embodiment, a multiwall sheet can comprise: non-intersecting polymer walls comprising outer layers and a transverse layer and/or a divider. The transverse layer and/or the divider extends from one of the polymer walls to another of the polymer walls to form cells. The multiwall sheet has a non-uniform cell density. In yet another embodiment, a multiwall sheet comprises: non-intersecting polymer walls comprising outer layers and transverse layers. The transverse layers intersect the walls to form cells. The multiwall sheet has a different number of inner layers, transverse layers, and/or dividers, in different portions of the sheet. The multiwall sheets can be used, for example, in a naturally light structure.