Borosilicate Glass Heat Shielding via Composition and Bending
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Solution Overview
Problem
Current window glasses for vehicles lack effective heat shielding properties, leading to increased energy consumption due to heat transfer from outside to inside the vehicle, which existing materials like soda lime glass and alkali borosilicate glass fail to adequately address.
Innovation Solution
A borosilicate glass with specific composition and processing conditions, including a range of SiO2, B2O3, Al2O3, and Fe2O3, is developed to achieve reduced light transmittance and scattering intensity when bent, enhancing heat shielding properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If conventional window glasses (soda lime glass or alkali borosilicate glass) are used, then the window glass can be manufactured with standard properties, but the heat shielding property is insufficient leading to high energy consumption
Solution Approach 1:
The patent applies parameter changes by precisely controlling the chemical composition parameters of the borosilicate glass (SiO2: 70-85%, B2O3: 5-20%, Al2O3: 0.7-10%, Fe2O3: 0.1-1%) and the bending temperature parameter (≥T12 where viscosity is 10^12 dPa·s) to achieve the desired heat shielding property while reducing energy consumption
Solution Approach 2:
The patent uses composite material principles by creating a borosilicate glass system that combines multiple oxide components (SiO2, B2O3, Al2O3, Fe2O3) in specific proportions to achieve superior heat shielding properties that cannot be obtained with conventional single-component or simpler glass systems
2Ease of manufacture
If the borosilicate glass is bent at high temperature to improve formability, then the glass can be shaped effectively, but the transmittance in the 900-1300 nm wavelength range may change affecting heat shielding
Solution Approach 1:
The patent applies preliminary action by pre-configuring the glass composition with specific amounts of Fe2O3 (0.1-1%) and other oxides before the bending process, so that when the glass is bent at temperature T12 or higher, the desired transmittance reduction in the 900-1300 nm range is achieved without requiring additional post-processing
Solution Approach 2:
The patent utilizes parameter changes by controlling the bending temperature parameter (≥T12 where viscosity is 10^12 dPa·s) to induce specific structural changes in the glass that reduce transmittance in the 900-1300 nm wavelength range, thereby improving heat shielding property during the forming process itself
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 borosilicate glass effectively reduces heat transfer through the vehicle windows, improving energy efficiency by maintaining low transmittance in specific wavelength ranges and enhancing heat shielding, thus reducing energy consumption.
Implementation Method 1
Tb−Ta>0 is satisfied where Tb [%] is an average transmittance of a light having a wavelength of 900 nm to 1300 nm when the borosilicate glass is a flat glass and a thickness of the flat glass is converted to 1.50 mm, and Ta [%] is an average transmittance of the light having a wavelength of 900 nm to 1300 nm when the thickness is converted to 1.50 mm in a case where the flat glass is heated and bent
Implementation Method 2
a bent glass having an excellent heat shielding property can be produced
Data Source
AI summary
A borosilicate glass includes: in mol % in terms of oxide, 70.0%≤SiO2≤85.0%; 5.0%≤B2O3 ≤20.0%; 0.70%≤Al2O3≤10.0%; 0.0%≤Li2O≤5.0%; 0.0%≤Na2O≤10.0%; 0.0%≤K2O≤5.0%; 0.0%≤MgO≤5.0%; 0.0%≤CaO≤5.0%; 0.0%≤SrO≤5.0%; and 0.10%≤Fe2O3≤1.0%, in which the borosilicate glass has a total amount of SiO2, Al2O3, and B2O3 of 85.0% or more, the borosilicate glass is substantially free of BaO, PbO, and As2O3, and Tb−Ta>0 is satisfied.