Coated Glass Sheet Heat Treatment with a Sacrificial Resin Layer
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Glass sheets used in glazings for buildings and vehicles often develop optical defects due to temperature differences across coated zones during high-temperature heat treatments, caused by varying emissivity of coatings that either reflect or absorb infrared radiation, leading to uneven heating and potential mechanical weakening or optical distortions.
Innovation Solution
A process involving a glass sheet with a first face coated with a mineral coating of varying emissivity, where a sacrificial resin layer is applied on higher emissivity zones, which combusts during heat treatment above 550°C, homogenizing the heating process and reducing temperature gradients.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If high-temperature heat treatment is applied to strengthen the glass sheet, then mechanical strength is improved, but optical defects appear due to temperature differences between coated zones
Solution Approach 1:
The patent applies a sacrificial layer with specific properties (combustible resin) to zones requiring higher temperature compensation. This creates local heterogeneity in the coating structure, allowing different zones to experience controlled temperature variations during heat treatment, thereby preventing optical defects while maintaining mechanical strength enhancement.
Solution Approach 2:
The sacrificial layer acts as an intermediary substance between the coating and the glass sheet. During heat treatment, this intermediate layer combusts to modify the thermal behavior of underlying zones, compensating for the temperature-lowering effect of low-emissivity coatings and ensuring uniform heating without direct contact between the heat source and the glass surface.
2Loss of energy
If low-emissivity coatings are applied to improve thermal insulation, then thermal properties are improved, but temperature differences between zones increase during heat treatment
Solution Approach 1:
The patent modifies specific zones by applying sacrificial layers to areas with low-emissivity coatings. These modified zones have different thermal characteristics during heat treatment, compensating for the temperature-lowering effect of low-emissivity coatings and ensuring more uniform heating across the entire glass sheet.
Solution Approach 2:
The patent changes the emissivity parameter of specific zones by applying sacrificial layers. During heat treatment, these layers combust to alter the thermal radiation properties of underlying areas, thereby adjusting temperature distribution to achieve better uniformity while maintaining the energy-saving benefits of low-emissivity coatings in other zones.
3Illumination intensity
If opaque enamel coatings are applied to provide aesthetic function, then appearance is improved, but zones absorb more infrared radiation and heat up excessively
Solution Approach 1:
The sacrificial layer serves as a temporary intermediary over opaque enamel coatings during heat treatment. It modifies the thermal interaction of these highly absorptive zones with infrared radiation, preventing excessive heat buildup while the enamel provides aesthetic appearance. The sacrificial layer combusts during treatment, leaving the enamel intact for its visual function.
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
This process significantly reduces temperature differences between coated zones, minimizing optical distortions and mechanical weakening, thereby improving the quality and reliability of glass products.
Implementation Method 1
applying, on at least one portion of said second zone, a sacrificial layer comprising a resin, then heat treating said coated glass sheet at a temperature of at least 550° C., during which step said sacrificial layer is removed by combustion
Implementation Method 2
The zones covered by a low-emissivity coating, which reflect infrared radiation, have a tendency to heat up less than the zones of greater emissivity, and the difference may also be aggravated by the presence, in certain zones of the glazing, of coatings that absorb infrared radiation
Data Source
AI summary
A process for obtaining a material including a glass sheet, includes providing a glass sheet including a first face coated at least partly by an essentially mineral first coating, the face having at least one first zone and at least one second zone, the at least one first zone having a higher emissivity than that of the second zone, then applying, on at least one portion of the second zone, a sacrificial layer including a resin, then heat treating the coated glass sheet at a temperature of at least 550° C., during which step the sacrificial layer is removed by combustion.