Enamel Paste Composition for Automotive Glazing Surface Roughness
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Solution Overview
Problem
Existing enamel paste compositions used in automotive glazing do not provide a smooth surface for thin functional coatings, leading to power loss and adverse effects on heating performance due to surface roughness.
Innovation Solution
An improved enamel paste composition with a bismuth silicate glass frit and a zinc silicate glass frit, which has a low firing temperature for a smooth surface, a high crystallization temperature to prevent damage to thin functional coatings, and good silver hiding and UV blocking properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If conventional enamel paste compositions are used, then the enamel layer provides UV blocking and silver hiding properties, but the surface roughness is high which causes power loss and degrades heating performance
Solution Approach 1:
The patent modifies the chemical composition parameters of the glass frit, specifically adjusting the ratios of SiO2, B2O3, Al2O3, and other oxides to achieve optimal firing characteristics. The particle size distribution parameters are also controlled within specific ranges (D10: 3-7 μm, D50: 8-12 μm, D90: 15-25 μm) to ensure smooth surface formation while maintaining functional properties
Solution Approach 2:
The enamel paste is formulated as a composite material system combining multiple glass frits with different functional properties: a first glass frit providing low-temperature firing characteristics, a second glass frit enhancing surface smoothness, and a third glass frit contributing to chemical stability. This composite approach allows simultaneous optimization of surface quality and energy efficiency
2Manufacturing precision
If the firing temperature is reduced to achieve a smooth surface, then surface roughness decreases, but the crystallization temperature may be compromised affecting the integrity of thin functional coatings
Solution Approach 1:
The firing process is divided into two distinct stages: a first firing stage at lower temperature (600-800°C) to remove organic carriers and initiate glass frit softening for surface smoothing, and a second firing stage at higher temperature (800-1000°C) to complete sintering and ensure crystallization resistance. This segmentation allows each stage to optimize for its specific function without compromising the other
Solution Approach 2:
The glass frit composition is engineered with specific oxide ratios that create a broad temperature window between the softening point (for surface smoothing) and crystallization temperature (for coating protection). The presence of B2O3, SiO2, and Al2O3 in optimized proportions ensures the frit remains vitrified and protective across the entire processing temperature range
3Manufacturing precision
If the enamel paste formulation is optimized for low firing temperature to achieve smooth surface, then surface roughness is reduced, but the silver hiding and UV blocking properties may be compromised
Solution Approach 1:
The enamel composition integrates three distinct glass frits, each contributing specific functional properties: the first glass frit (SiO2-B2O3-Al2O3 system) provides low-temperature firing and surface smoothing; the second glass frit enhances surface quality; the third glass frit contributes to optical properties including UV absorption and silver hiding. This composite structure enables simultaneous achievement of smooth surface and effective shielding properties
Solution Approach 2:
The glass frit composition is designed to perform multiple functions simultaneously: surface smoothing during firing, UV radiation blocking, and silver hiding. The synergistic combination of various oxides (SiO2, B2O3, Al2O3, ZnO, PbO, etc.) creates a multi-functional material that achieves surface quality and optical shielding without requiring separate layers or additional processing steps
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 improved enamel paste composition achieves a smooth surface with low surface roughness, maintains the integrity of thin functional coatings during processing, and provides excellent silver hiding and UV blocking characteristics, enhancing the heating performance and aesthetic appearance of automotive glazing.
Implementation Method 1
a first 'pre-firing' heating step, at a temperature below the melting temperature of the glass frit in the enamel paste, in order to remove organic carrier medium components of the enamel paste, thus forming a dry, pre-fired layer; and (ii) a second 'firing' heating step at a temperature above the melting point of the glass frit in the enamel paste to fuse the enamel
Implementation Method 2
during which the organic carrier medium of the paste or ink burns off
Implementation Method 3
the organic carrier medium of the paste or ink burns off
Implementation Method 4
the enamel fuses together and establishes a bond to the substrate
Data Source
Figure 1
Figure 2
Figure 3(a)~3(b)
AI summary
An enamel paste composition is provided for fabricating a coated glass article comprising a glass substrate, an enamel layer disposed on the glass substrate, and a thin coating having a thickness of no greater than 0.5 micrometres disposed on the enamel layer. The enamel paste composition is formulated such that it provides a smooth surface and does not crystallize during processing of the coated glass article, thereby improving the quality of the thin coating disposed thereon.