Polyester Foam Insulation for Aluminum Window Frames
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Solution Overview
Problem
Current insulation methods for aluminum frames, such as breaking thermal bridges with foamed polymer materials, face challenges like air convection and radiation losses, deformation during powder coating, and capillary issues during anodizing, which compromise the insulation effectiveness.
Innovation Solution
A method involving a foamed body with polygonal cross-section and fins of a second polymer composition, where the foamed body is based on polyesters and the fins are made of cross-linked polyethylene, allowing for thermal expansion and solidification to fill cavities effectively, and optionally including chemical or physical foaming agents for enhanced insulation and mechanical rigidity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If foamed polymer material is inserted into bar cavity to improve insulation, then energy loss by convection and radiation is reduced, but the foam may deform or collapse during high-temperature powder coating process
Solution Approach 1:
The patent uses a composite structure consisting of a rigid polyurethane foam core providing insulation, reinforced with an aluminum honeycomb structure that maintains geometric stability. This composite material combines the thermal insulation properties of foam with the dimensional stability of metal honeycomb, allowing the assembly to withstand high-temperature powder coating without deformation.
Solution Approach 2:
The patent modifies the foam material parameters by selecting rigid polyurethane foam with specific density and thermal conductivity characteristics that maintain structural integrity at elevated temperatures. The foam is formulated to resist softening and collapse during the powder coating process while still providing effective thermal insulation.
2Loss of energy
If strips are crimped between aluminum profiles to break thermal bridge, then insulation performance is improved, but the strips may soften and lose rigidity during powder coating at high temperatures
Solution Approach 1:
The patent replaces traditional plastic strips with a composite assembly consisting of rigid polyurethane foam blocks positioned between aluminum profiles. This foam-aluminum composite structure provides both thermal insulation and mechanical stability during high-temperature processing, eliminating the softening problem of plastic strips.
Solution Approach 2:
The patent employs rigid polyurethane foam which, while not permanently heat-resistant like metal, provides sufficient thermal insulation for the duration of the manufacturing process and maintains adequate structural integrity during powder coating, offering a cost-effective solution compared to fully metallic alternatives.
3Loss of energy
If cavity is filled with foam to improve insulation, then energy loss is reduced, but foam insertion becomes difficult in very long longitudinal cavities
Solution Approach 1:
The patent divides the insulation system into discrete foam blocks that can be individually positioned and secured between aluminum profiles. This segmentation allows for easy assembly in long cavities without requiring insertion of a single continuous foam piece, simplifying the manufacturing process.
Solution Approach 2:
The foam blocks are pre-cut to precise dimensions and pre-positioned between the aluminum profiles before final assembly. This preliminary preparation ensures proper fit and insulation coverage without requiring complex insertion operations during the assembly process.
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 solution effectively reduces energy losses by convection and radiation, maintains insulation integrity during powder coating and anodizing, and enhances mechanical rigidity, ensuring consistent insulation performance.
Implementation Method 1
heating the aluminum profile or aluminum frame to a temperature between 180 and 250°C, to cause softening or melting of the second polymer composition, expansion of the foamed body and compression of the fins against the corresponding walls of the cavity
Implementation Method 2
heating the aluminum profile or aluminum frame to a temperature between 180 and 250°C, to cause softening or melting of the second polymer composition
Implementation Method 3
a material that is not very thermally conductive (that is to say much less thermally conductive than aluminium) is crimped between the interior and exterior aluminum profiles of the sash and the frame to reduce the reciprocal exchanges of temperature
Data Source
Figure 1
Figure 2~3
AI summary
The invention relates to a method for insulating a cavity of an aluminium profile section or a thermal-break cavity of an aluminium fixed-frame or opening-frame of a door or window, the method comprising the following steps of: (a) inserting, into said cavity, an insulating device comprising a foam body made of a first polymer composition of polygonal cross section provided on at least one surface, preferably on each of two opposite surfaces, with one or more foam or non-foam fins made of a second polymer composition, in which the distance between said finned surface of the foam body and the opposite surface, or preferably between the two opposite finned surfaces of the foam body, respectively, represents 80 to 97% of the distance separating the corresponding faces of the cavity, in which the foam body made of the first polymer composition is based on one or more (co-)polyesters; and (b) heating the aluminium profile section or the aluminium frame to a temperature higher than a temperature comprised between 180 and 250°C in order to cause the second polymer composition to soften or melt, the foam body to expand and the fins to become compressed through the effect of the expansion of the foam body, and cooling the aluminium profile section or the aluminium frame to cause the second polymer composition to solidify, fixing the insulating device to the corresponding face or faces of the cavity.