Water-Based Frit Slurry Paste for Low-Temperature Vacuum Glass Sealing
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Solution Overview
Problem
Conventional vacuum insulated glass units face issues with high processing temperatures that compromise the temper strength of glass substrates and introduce environmental hazards due to the use of lead-based frits and organic solvents, leading to undesirable heat exposure, stress, and potential breakage, as well as environmental toxicity.
Innovation Solution
A water-based frit slurry paste using lead-free bismuth or ceramic powders with a binder like methylcellulose, which can be fired to create a hermetic seal with reduced temperature requirements and lower environmental impact, maintaining adequate adhesion and minimizing bubble formation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If conventional high temperature processing (approximately 500°C) is used to form hermetic peripheral seals, then the glass frit melts and forms a strong edge seal, but the temper strength of glass substrates is compromised and the glass may break
Solution Approach 1:
The patent changes the chemical composition parameters of the frit material by using lead-free alternatives (such as zinc oxide, bismuth oxide, or ceramic powders) that have different melting characteristics. This allows the frit to melt and form strong seals at lower temperatures (below 500°C), thereby resolving the contradiction between achieving strong edge seals and avoiding excessive processing temperatures that would compromise glass temper strength.
2Reliability
If lead-based frits and organic solvents are used in conventional frit slurry pastes, then the frit forms effective hermetic seals, but environmental toxicity and harmful effects are introduced
Solution Approach 1:
The patent replaces expensive and toxic lead-based frits with cheaper, non-toxic alternatives such as zinc oxide, bismuth oxide, or ceramic powders. These alternative materials achieve the same hermetic sealing function without the environmental hazards associated with lead, thereby resolving the contradiction between effective seal formation and environmental toxicity.
Solution Approach 2:
The patent changes the chemical composition parameters of the frit by substituting lead-containing compounds with lead-free compounds. This parameter change maintains the functional performance of the frit in forming hermetic seals while eliminating the harmful environmental effects associated with lead-based materials.
3Strength
If high processing temperatures are applied to the entire assembly for edge seal formation, then the glass frit melts and wets the surfaces, but the low-E coatings on glass substrates are adversely affected
Solution Approach 1:
The patent changes the melting temperature parameter of the frit material by using lead-free alternatives that melt at lower temperatures. This allows the frit to become fluid and wet the glass surfaces sufficiently for seal formation at temperatures below 500°C, which is low enough to avoid damaging the low-E coatings on the glass substrates.
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 solution reduces the loss of temper strength in glass substrates, minimizes environmental harm, and allows for stable, non-toxic frits that can be easily processed and applied, providing a durable and environmentally friendly edge seal for vacuum insulated glass units.
Implementation Method 1
the glass frit melts, wets the surfaces of the glass sheets 2, 3, and ultimately forms hermetic peripheral or edge seal 4
Implementation Method 2
the glass frit melts, wets the surfaces of the glass sheets 2, 3, and ultimately forms hermetic peripheral or edge seal 4
Data Source
AI summary
Certain example embodiments of this invention relate to a frit slurry paste for use in assemblies (e.g., a vacuum insulated glass unit or a plasma display panel), and methods of making the same. Frit powder, binder material, and a water-based solvent are mixed together to form an intermediate mixture. The frit powder is substantially lead free, and the water-based solvent is provided at a first temperature. Additional water-based solvent is added to the intermediate mixture to form a frit slurry paste. The additional water-based solvent is provided at a second temperature, with the second temperature being lower than the first temperature. The binder material is provided at a concentration of 0.001%-20% by weight with respect to the frit slurry paste or the frit slurry paste absent the frit powder. The frit slurry paste has a bulk viscosity of 2,000-200,000 cps.