Multiwall Sheet Nanoporous Foam Thermal Insulation

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Solution Overview

Problem

Multiwall sheets face challenges in achieving low thermal conductivity values while maintaining structural integrity and cost-effectiveness, as the thermal insulation properties saturate with the addition of more walls, and existing methods like coatings or surface texturing increase costs and cycle times.

Innovation Solution

Incorporating nanoporous polymer foam material into the layers of multiwall sheets, either during coextrusion or as a secondary process, to reduce thermal conductivity and enhance insulation, with the foam material filling between adjacent walls, allowing for improved thermal performance without increasing cost or mass.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of energy

If the number of walls in multiwall sheet is increased to lower thermal conductivity, then thermal insulation performance is improved, but manufacturing complexity and cost increase

Engineering Contradiction:

Improvethermal conductivityVSAvoidnumber of walls

Core Design Contradiction:

Loss of energyVSDevice complexity

Solution Approach 1:

The patent introduces nanoporous foam material filling within the chambers formed by adjacent walls. The nanoporous structure (with pore sizes typically 1-100 nanometers) creates additional thermal resistance through radiative heat transfer blocking and enhanced conductive resistance, achieving superior insulation without increasing the number of walls

Inventive Principle:

Principle #31Porous materials

Solution Approach 2:

The patent combines the multiwall sheet structure with nanoporous foam material to create a composite thermal insulation system. This composite approach leverages both the reflective/insulative properties of the multiwall geometry and the unique thermal blocking properties of nanoporous materials, achieving synergistic thermal performance

Inventive Principle:

Principle #40Composite materials

2Loss of energy

If coatings are applied to reduce thermal conductivity, then thermal insulation is improved, but manufacturing cost increases

Engineering Contradiction:

Improvethermal conductivityVSAvoidmanufacturing cost

Core Design Contradiction:

Loss of energyVSEase of manufacture

Solution Approach 1:

The patent uses nanoporous foam material as an alternative to surface coatings. This material is integrated within the existing multiwall structure during manufacturing, eliminating the need for separate coating application steps while providing superior thermal insulation through its nanoporous architecture that blocks radiative and conductive heat transfer

Inventive Principle:

Principle #31Porous materials

3Loss of energy

If surface texturing is added to increase thermal conductivity control, then thermal performance is improved, but manufacturing cycle time increases

Engineering Contradiction:

Improvethermal conductivityVSAvoidmanufacturing cycle time

Core Design Contradiction:

Loss of energyVSLoss of time

Solution Approach 1:

The patent merges the thermal insulation function with the existing multiwall sheet manufacturing process by co-introducing the nanoporous foam material during the same extrusion or assembly operation. This eliminates the need for separate surface texturing or coating steps, maintaining production speed while achieving enhanced thermal control

Inventive Principle:

Principle #5Merging (Combining)

4Loss of energy

If more walls are added to reduce thermal conductivity further, then thermal insulation is improved, but mass and cost increase

Engineering Contradiction:

Improvethermal conductivityVSAvoidmass

Core Design Contradiction:

Loss of energyVSWeight of stationary object

Solution Approach 1:

The patent employs nanoporous foam material that provides high thermal resistance per unit mass. The nanoporous structure (with extremely small pore sizes) creates numerous heat transfer pathways that are difficult for thermal energy to penetrate, achieving superior insulation performance without the mass penalty of adding more solid wall structures

Inventive Principle:

Principle #31Porous materials

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 use of nanoporous foam material in multiwall sheets achieves a significant reduction in thermal conductivity, often by 70% or more, compared to unfilled layers, while maintaining structural integrity and reducing production costs, thereby enhancing thermal insulation capabilities.

Implementation Method 1

the layer is filled with a nanoporous foam material; and wherein the multiwall sheet comprises a normalized thermal conductivity value of less than or equal to 1.00 W·m/kg·K

Methodology Applied

Scientific EffectThermal Insulation: Thermal Insulation

Implementation Method 2

Incorporating nanoporous polymer foam material into the layers of multiwall sheets

Methodology Applied

Scientific EffectNanoporous Material: Nanoporous Material

Data Source

PatentEP2732107B1A multiwall sheet, methods of making, and articles comprising the multiwall sheet

Publication Date: 2023.04.05 SABIC GLOBAL TECHNOLOGIES BV

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Figure 3

AI summary

A multiwall sheet can comprise walls, wherein the walls include: a first wall; a second wall; and a transverse wall, wherein the first wall, the second wall, and the transverse wall extend longitudinally; and a rib extending between adjacent walls, wherein a layer is formed by two adjacent walls; wherein the layer is filled with a nanoporous foam material; and wherein the multiwall sheet comprises a normalized thermal conductivity value of less than or equal to 1.00 W·m/kg·K. A method of making a multiwall sheet can comprise coextruding the multiwall sheet described above with a nanoporous foam material; wherein the layer is filled with a nanoporous foam material during coextrusion.