Silica-Graphite Foam Composition for Low Thermal Conductivity
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Solution Overview
Problem
Vinyl aromatic polymer foams face challenges with high thermal conductivity, poor mechanical stability, and self-extinguishing properties due to the use of carbon-based additives, which also affect bubble formation and foam deformation, and require high amounts of brominated flame retardants for acceptable flammability.
Innovation Solution
The use of a specific type of silica and graphite in a specific weight ratio, combined with other additives, decreases thermal conductivity without adversely affecting mechanical and flammability properties, and reduces the required graphite content while maintaining thermal performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If carbon-based additives (carbon black, graphite) are used to decrease thermal conductivity, then thermal insulation performance is improved, but self-extinguishing properties deteriorate and mechanical stability worsens
Solution Approach 1:
The patent employs a composite additive system combining inorganic heat scatterers (silica, titanium oxide) with infrared reflectors (aluminum pigment, graphite) to achieve thermal insulation without relying on carbon-based heat absorbers. This composite approach allows the foam to scatter and reflect heat radiation effectively while maintaining good self-extinguishing properties, as the inorganic components do not promote combustion like carbon-based additives do.
Solution Approach 2:
The patent changes the type of additives from carbon-based (organic) to inorganic-based, fundamentally altering the chemical composition parameters. This substitution removes the combustion-promoting characteristics of carbon while maintaining thermal insulation through physical heat scattering and reflection mechanisms, thereby improving self-extinguishing properties while achieving the desired thermal performance.
2Loss of energy
If carbon-based additives are used to decrease thermal conductivity, then thermal insulation performance is improved, but mechanical stability deteriorates
Solution Approach 1:
The patent uses a composite system of inorganic fillers (silica, titanium oxide) combined with infrared reflectors to achieve thermal insulation. These inorganic materials provide structural support and do not compromise the mechanical integrity of the polymer matrix, unlike carbon-based additives that create weak interfaces and reduce mechanical stability.
3Loss of energy
If carbon-based additives are used to decrease thermal conductivity, then thermal insulation performance is improved, but foam deformation increases
Solution Approach 1:
The patent changes the chemical composition from carbon-based to inorganic-based additives, which do not undergo thermal degradation or oxidation that would cause foam collapse. The inorganic materials remain stable at foam processing and service temperatures, preventing the deformation and shrinkage issues associated with carbon-based additives.
4Loss of energy
If carbon black is used to decrease thermal conductivity, then thermal insulation performance is improved, but brominated flame retardant requirement increases
Solution Approach 1:
The patent extracts and removes carbon-based additives from the formulation, eliminating the need for high levels of brominated flame retardants that would be required to compensate for the combustion-promoting effects of carbon black. By using inorganic heat scatterers instead, the system achieves thermal insulation without the combustion risk, allowing for reduced flame retardant usage.
5Reliability
If mineral athermanous additives are used to improve self-extinguishing properties, then flammability resistance is improved, but thermal conductivity decreases less effectively
Solution Approach 1:
The patent combines inorganic heat scatterers (silica, titanium oxide) with infrared reflectors (aluminum pigment) to create a composite system that provides both heat scattering and infrared reflection. This dual-mechanism approach achieves superior thermal conductivity reduction compared to heat scatterers alone, while the inorganic composition maintains good self-extinguishing properties.
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 combination of silica and graphite in vinyl aromatic polymer foams achieves reduced thermal conductivity, improved mechanical properties, and enhanced self-extinguishing capabilities, while minimizing the need for brominated flame retardants, resulting in stable and effective thermal insulation materials.
Implementation Method 1
the addition of athermanous additives from the group of heat absorbers (e.g. carbon black), heat scatterers (e.g. minerals from the group of silicas and titanium oxides) and heat reflectors (e.g. aluminium pigment and graphite) decreases the thermal conductivity of vinyl aromatic polymer foams
Implementation Method 2
the addition of athermanous additives from the group of heat absorbers (e.g. carbon black), heat scatterers (e.g. minerals from the group of silicas and titanium oxides) and heat reflectors (e.g. aluminium pigment and graphite) decreases the thermal conductivity of vinyl aromatic polymer foams
Implementation Method 3
Such foams, having black or grey colour, absorb a relatively high amount of heat energy, thus the insulation boards made thereof and applied on building walls can shrink or deform significantly
Data Source
AI summary
The invention relates to the co-use of a) a certain type of silica and b) a certain type of graphite, wherein the silica and the graphite are used in a weight ratio in a range of from 1:1 to 1:10, for decreasing the thermal conductivity of vinyl aromatic polymer foam.