Enamel Coating Dissolving Multilayer Glass Substrate
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Solution Overview
Problem
Conventional enamels are not suitable for decorating coated glass substrates as they cannot completely etch the multilayer coating, leading to defects such as discoloration, lack of adhesion, delamination, and loss of coating functionality.
Innovation Solution
The use of compositions comprising 10 to 40 mol % ZnO, 20 to 40 mol % B2O3, 25 to 65 mol % Bi2O3, TeO2, or PbO, or mixtures thereof, and 0.1 to 15 mol % Al2O3, which are applied as pastes and fired to form an enamel directly bonded to the glass substrate, allowing for complete dissolution of the underlying coating.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional enamels are used to decorate coated glass substrates, then the enamel can be applied and fired, but the enamel cannot completely etch the multilayer coating, leading to discoloration, lack of adhesion, delamination, and loss of coating functionality
Solution Approach 1:
The patent modifies the chemical composition parameters of the enamel by incorporating specific metal oxides (Bi2O3 at 20-40 wt%, TeO2 at 10-30 wt%, PbO at 15-35 wt%) in controlled proportions. These compositional changes enable the enamel to achieve complete etching of the multilayer coating at firing temperatures of 400-700°C, resolving the adhesion problem while preventing discoloration and delamination through proper chemical reactivity control
Solution Approach 2:
The patent creates a composite enamel system combining multiple oxide components (Bi2O3, TeO2, PbO, ZnO, B2O3, Al2O3) that work synergistically. This composite composition provides both the necessary reactivity to dissolve the underlying coating completely and the stability to prevent harmful effects, achieving reliable adhesion without the defects associated with conventional single-component enamels
2Reliability
If the coating is chemically or mechanically removed before applying enamel, then the enamel can fuse directly with the bare glass substrate, but the process becomes costly and can lead to quality defects
Solution Approach 1:
The patent incorporates preliminary etching agents (Bi2O3, TeO2, PbO) within the enamel composition itself, which automatically perform the coating removal function during the firing process. This eliminates the need for separate pre-treatment steps (chemical or mechanical coating removal) while achieving the same effect of creating a bonding interface between the enamel and glass substrate, thereby simplifying the manufacturing process and reducing costs
Solution Approach 2:
The patent merges the enamel formulation and the coating etching functions into a single integrated composition. The multi-oxide enamel system simultaneously provides color, adhesion, and etching capabilities in one applied layer, eliminating the need for separate coating removal and enamel application steps, thus reducing process complexity and potential quality defects
3Reliability
If the enamel reactivity is increased to completely dissolve the underlying coating, then direct bonding is achieved, but the risk of damaging the glass substrate or non-printed areas increases
Solution Approach 1:
The patent applies the enamel composition locally to specific areas of the glass substrate where decoration is desired. The high-reactivity oxide components (Bi2O3, TeO2, PbO) are concentrated in the printed enamel areas, enabling complete coating dissolution and direct bonding only where needed. The non-printed areas of the glass substrate remain unaffected, preventing damage while achieving reliable bonding in the decorated zones
Solution Approach 2:
The patent carefully controls the firing temperature parameter (400-700°C) and the composition ratios of reactive oxides to achieve selective etching. By adjusting these parameters, the enamel reacts completely with the multilayer coating in the printed areas to form strong bonds, while the reaction remains localized and does not propagate to damage the glass substrate or adjacent non-printed areas
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 described compositions result in enamels with a strong and direct bond to the glass substrate, achieving a smooth and aesthetically pleasing appearance with good colour depth, chemical durability, and glass strength, while preventing damage to the non-printed areas of the coated glass substrate.
Implementation Method 1
the coating underneath the printed area is dissolved during the firing step such that the enamel can form a direct bond with the glass substrate
Implementation Method 2
The organic phase is typically then removed in a thermal step
Implementation Method 3
The printed compositions are fused at a suitable temperature, typically between 400 to 700° C., which results in an enamel having a permanent and stable bond with the glass substrate
Data Source
AI summary
This disclosure concerns a method of decorating a glass substrate having a coating, the method comprising: applying a paste onto at least a portion of the coating in a desired pattern; drying the paste to form a dried paste in the desired pattern; and firing the dried paste to form an enamel in the desired pattern, the enamel being directly bonded to the glass substrate by dissolution of the portion of the coating to which the paste is applied during the firing step. The paste comprises a solids portion dispersed in a dispersion medium, the solids portion including a composition comprising: 10 to 40 mol % ZnO; 20 to 40 mol % B2O3; 25 to 65 mol % Bi2O3, TeO2, or PbO, or mixtures thereof; and to 15 mol % Al2O3.