Laminated Glazing with Adhesive Interlayer for Thermal Contraction
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Laminated glazing structures face issues with differential thermal expansion between polymer materials and mineral glass, leading to deformation and optical quality degradation due to the bimetallic effect, particularly evident as undulations or 'mottle' during cooling.
Innovation Solution
A laminated glazing system comprising a sheet of transparent polymer material and a thin mineral glass, bonded with an adhesive interlayer of specific hardness (≤70 Shore A) and thickness, which decreases with glass thickness, ensuring a regular surface and reduced thermal expansion mismatch.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the polymer material is bonded to the glass sheet via heating to 100-120°C, then bonding is achieved, but the polymer shrinks more than the glass during cooling, causing deformation and undulations
Solution Approach 1:
The patent changes the bonding temperature parameter to a lower range (60-80°C) that is sufficient for adhesive activation but below the threshold that causes excessive polymer shrinkage. This temperature optimization resolves the contradiction by achieving adequate bonding while preventing the dimensional changes that lead to surface deformation.
Solution Approach 2:
The patent introduces a specifically formulated adhesive interlayer as a mediator between the polymer and glass. This adhesive layer with controlled thickness (0.5-2.0 mm) and composition acts as a buffer that compensates for differential thermal contraction, allowing bonding to occur without transmitting the full shrinkage stress to the glass surface, thereby preventing undulations.
2Shape
If the adhesive interlayer thickness is increased to eliminate mottle, then surface regularity is improved, but the structural efficiency and bonding performance may be compromised
Solution Approach 1:
The patent optimizes the adhesive interlayer thickness to a specific range (0.5-2.0 mm) that provides sufficient material to absorb thermal contraction differences and maintain surface flatness, while remaining thin enough to preserve structural efficiency and bonding performance. This precise parameter control resolves the contradiction between surface regularity and structural strength.
3Weight of moving object
If thin glass sheets (0.5-1.5 mm) are used to reduce weight, then weight is reduced, but they are more susceptible to deformation from thermal expansion differences
Solution Approach 1:
The adhesive interlayer serves as a protective intermediary that cushions thin glass sheets from the full impact of differential thermal contraction with the polymer. This allows the use of weight-reducing thin glass while maintaining dimensional stability through the compliant adhesive layer that absorbs expansion/contraction stresses.
Solution Approach 2:
The patent modifies the bonding temperature parameter to a lower range that reduces the magnitude of thermal contraction in the polymer, thereby minimizing the dimensional stress imposed on thin glass sheets. This parameter change enables the use of thin, lightweight glass while maintaining its dimensional stability during the bonding and cooling process.
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 effectively eliminates undulations, maintaining optical quality and mechanical resistance, suitable for demanding applications like aeronautics, with enhanced resistance to temperature variations and external impacts.
Implementation Method 1
When cooling, the polymer material shrinks much more than thin glass, which then tends to deform, forming undulations
Implementation Method 2
differential thermal expansion between polymer material and mineral glass at the laminate assembly temperatures, called the bimetallic effect
Implementation Method 3
a 200 nm thick layer of indium tin oxide (or indium tin oxide doped with tin or ITO for the English name: Indium Tin Oxide)... the face of the glass sheet oriented towards the adhesive interlayer carries a heating layer
Data Source
AI summary
The invention relates to a glass panel essentially made up of a transparent polymer material sheet with a thickness of 5 to 25 mm and a glass sheet with a thickness of 0.5 to 1.5 mm that are adhered to each other by an adhesive insert, the hardness of which is less than or equal to 70 Shore A at a temperature greater than or equal to -5°C and the thickness of which decreases depending on the thickness of the glass sheet. An adhesive insert thickness of 2.0 mm is sufficient for a glass sheet thickness of 0.55 mm, and an adhesive insert thickness of 1.25 mm is sufficient for a glass sheet thickness of 1.25 mm. The invention also relates to the use of said glass panel for a ground, air, or water transport vehicle, the vehicle surface in contact with the outer atmosphere being made up of one so-called "glass sheet."