Multilayer Plastic Glazing with ITO Nanoparticles for Low Energy Transmission
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Solution Overview
Problem
Conventional transparent thermoplastic polymers used in glazing materials, such as polycarbonate, exhibit high thermal permeability to infrared radiation, leading to undesirable heating in vehicles and buildings, which increases energy consumption and reduces occupant comfort, while existing IR-absorbing additives face issues with thermal stability, coloration, and efficiency.
Innovation Solution
A multilayer structure comprising a transparent thermoplastic base layer with nanoparticles of indium tin oxide (ITO) or antimony-doped tin oxide, combined with an IR-reflecting multilayer layer, providing low primary and secondary energy transmission with minimal inherent color and high thermal stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If transparent thermoplastic polymers are used in glazing materials, then design freedom and breakage resistance are improved, but thermal permeability increases leading to undesirable heating
Solution Approach 1:
The patent uses composite materials by combining transparent thermoplastic polymers with inorganic infrared absorbers (such as metal oxides, metal borides, or core-shell particles) to create a multilayer structure that maintains transparency while reducing thermal permeability. This composite approach allows the material to simultaneously provide breakage resistance and thermal protection.
Solution Approach 2:
The patent applies local quality by incorporating infrared-absorbing additives specifically in layers where thermal protection is needed, while maintaining transparent thermoplastic layers for structural integrity and visibility. The multilayer structure allows different regions to have different functions: some layers absorb IR radiation locally while other layers maintain transparency and structural strength.
2Loss of energy
If infrared absorbers are added to reduce thermal permeability, then energy transmission is reduced, but the additives suffer from low thermal stability or strong inherent color
Solution Approach 1:
The patent changes the parameters of the infrared absorbers by selecting inorganic materials with specific properties (metal oxides, metal borides, or core-shell structures) that have both high thermal stability and appropriate absorption characteristics. By adjusting the particle size, composition, and concentration of these inorganic additives, the patent achieves effective IR absorption while maintaining thermal stability at processing temperatures up to 330°C and service temperatures above 50°C.
Solution Approach 2:
The patent replaces expensive or unstable organic infrared absorbers with more stable inorganic alternatives that, while potentially having inherent color, provide long-term reliability. The use of inorganic materials like metal oxides and borides offers better price/performance ratio and sustained performance over time despite initial coloration concerns.
3Reliability
If inorganic infrared absorbers are used to improve thermal stability, then heat absorption is enhanced, but inherent color increases reducing transparency
Solution Approach 1:
The patent applies local quality by using core-shell particles where the core provides infrared absorption and the shell provides transparency. This allows the infrared-absorbing inorganic material to be localized in the core while the transparent shell material surrounds it, creating a particle that absorbs IR radiation but remains transparent or translucent in the visible range.
Solution Approach 2:
The patent manages coloration effects by selecting inorganic materials and particle characteristics that minimize visible light absorption. By controlling particle size, composition, and distribution, the patent reduces the inherent color of inorganic infrared absorbers while maintaining their thermal stability and IR absorption capabilities.
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 multilayer structure achieves high visible light transmission with low primary and secondary energy transmission, maintaining occupant comfort while reducing energy consumption and avoiding coloration issues, suitable for long-term use in glazing applications.
Implementation Method 1
at least 0.038% by weight to 0.5% by weight of nanoparticles based on indium tin oxide (ITO) and/or antimony-doped tin oxide (ATO), based on the total weight of the plastic composition for the base layer, as an IR absorber
Implementation Method 2
at least one multilayer layer reflecting IR radiation, which has different plastics and different refractive indices in the immediately adjacent layers
Implementation Method 3
The multilayer structure achieves high visible light transmission with low primary and secondary energy transmission
Data Source
AI summary
The invention relates to a multilayer structure comprising a base layer that contains at least one transparent thermoplastic material and a special inorganic infrared absorber, said multilayer structure further comprising an IR reflective multi-ply layer. The invention further relates to the production of such a multilayer structure and the use thereof for producing plastic glazings in buildings, automobiles, railway vehicles and aircraft.