Flat Glass Pane Ion Exchange Strengthening
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Solution Overview
Problem
Existing methods for strengthening glass, such as thermal and chemical prestressing, are costly and time-consuming, especially when using specialty glasses, and do not efficiently produce glass panes with high strength for mass production.
Innovation Solution
A flat glass pane is produced with a surface layer enriched in potassium and depleted in sodium and/or lithium, and an inner layer that is not enriched in potassium and not depleted in sodium and/or lithium, using a combination of thermal and chemical hardening processes, including a controlled ion exchange method that reduces treatment times and uses conventional glass materials.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If thermal prestressing is used to increase fracture strength, then glass strength is improved, but production cost and complexity increase
Solution Approach 1:
The patent modifies the chemical composition parameters of the glass, specifically using a silica content of 70-74 wt% and controlled alkali metal oxide content, to enable effective chemical prestressing that achieves high fracture strength without requiring complex thermal treatment equipment or processes
2Strength
If low-temperature ion exchange is used to strengthen glass, then glass strength is improved, but treatment time becomes very long (8-36 hours)
Solution Approach 1:
The patent changes the chemical parameters by using a salt melt with specific composition (containing potassium chloride and calcium chloride in controlled ratios) and controlling the water content (0.5-5 wt%) to accelerate the ion exchange process, reducing treatment time from 8-36 hours to just 2-8 hours while maintaining strengthening effectiveness
Solution Approach 2:
The patent uses a composite salt melt system combining potassium chloride and calcium chloride with specific ratios, where calcium chloride acts as a flux to accelerate the ion exchange process, enabling faster treatment times while achieving the desired compressive stress layer and fracture strength
3Loss of time
If specialty glass is used with multistage treatment methods, then long process times are reduced, but production cost increases
Solution Approach 1:
The patent modifies the base glass composition parameters (silica 70-74 wt%, alkali metal oxides 10-14.5 wt%, alkaline earth metal oxides 12-17 wt%) to be optimally suited for single-stage chemical prestressing, eliminating the need for expensive specialty glasses and multistage treatment processes while achieving high fracture strength
Solution Approach 2:
The patent employs a relatively simple salt melt composition (potassium chloride and calcium chloride) that can be easily prepared and used in single-stage treatment, replacing complex multistage treatment systems and expensive specialty glasses, thereby reducing production costs while maintaining effective strengthening
4Device complexity
If standard commercial glass is used for ion exchange, then material cost is reduced, but treatment time becomes very long
Solution Approach 1:
The patent optimizes the chemical parameters of standard commercial glass by controlling the silica content (70-74 wt%) and alkali metal oxide content (10-14.5 wt%), which enhances the glass's responsiveness to ion exchange processes, allowing faster treatment times (2-8 hours) while using cost-effective standard glass materials
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 process achieves significantly higher strength values, including bending fracture strength and scratch resistance, while reducing material usage and production costs, resulting in lighter and more cost-effective glass panes with enhanced fracture strength.
Implementation Method 1
a surface layer is enriched in potassium and depleted in sodium and/or lithium, while an inner layer, more particularly an inner layer directly bordering the surface layer, is not enriched in potassium and not depleted in sodium and/or lithium
Implementation Method 2
The blank is heated to a primary temperature which lies at most 50 kelvins below and at most 30 kelvins above the Littleton softening point of the glass material, and is then quenched to a quenching temperature which lies at least 200 kelvins and at most 550 kelvins, more particularly at least 200 kelvins and at most 450 kelvins, below the primary temperature
Data Source
AI summary
The invention relates to a flat glass pane made of a base material, which is an alkali-containing silicate glass. The flat glass pane is characterized in that at least one surface layer is enriched with potassium and is depleted of sodium and/or lithium while an inner layer, in particular an inner layer directly adjoining the surface layer, is not enriched with potassium and is not depleted of sodium and/or lithium; and the flat glass pane has a compressive stress up to a compressive stress depth and a tensile stress starting from the compressive stress depth, wherein the tensile stress increases as the depth increases up to a tensile stress maximum arranged in the inner layer, and/or the curve of the tensile stress does not have a linear section depending on the depth, and/or the curve of the tensile stress does not have a section in which the tensile stress is constant depending on the depth.