Laminated Glass Adhesion Control via Alkali Ions
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Solution Overview
Problem
Laminated glass with low plasticizer content struggles to achieve optimal penetration resistance due to high adhesion issues when using traditional adhesion control agents, particularly with thin PVB films in contact with glass surfaces, which fail to meet impact requirements such as those stipulated by ECE R43.
Innovation Solution
Incorporating a specific amount of alkali metal ions, preferably potassium ions, into the thin low-plasticizer PVB film, along with limited alkaline earth ions, to adjust adhesion levels, ensuring a laminated glass structure with a thin film having less than 16% plasticizer content and a thicker film with standard plasticizer content, achieving balanced adhesion and penetration resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If traditional adhesion control agents (metal salts) are added to thin low-plasticizer PVB films, then adhesion to glass surface increases, but penetration resistance deteriorates
Solution Approach 1:
The patent changes the chemical composition parameters of the PVB film by incorporating specific adhesion control agents (metal salts such as magnesium, calcium, or zinc salts of carboxylic acids) at controlled concentrations (0.1-10% by weight) to reduce adhesion between the interlayer and glass surface, thereby improving penetration resistance while maintaining structural integrity
Solution Approach 2:
The patent creates a composite material system combining PVB polymer matrix with dispersed metal salt particles, where the composite structure provides both the necessary adhesion properties and penetration resistance by controlling the distribution and type of metal salts within the low-plasticizer PVB film
2Reliability
If plasticizer content is reduced in PVB film, then penetration resistance improves, but adhesion control becomes difficult
Solution Approach 1:
The patent modifies the chemical parameters by reducing plasticizer content to less than 16% (preferably 1-15%) and simultaneously adjusting adhesion control agent concentration to achieve the desired balance between penetration resistance and adhesion properties
Solution Approach 2:
The patent applies different functional properties to different regions of the interlayer system by using thin PVB films (first interlayer) with low plasticizer content for penetration resistance and thicker PVB films (second interlayer) with standard plasticizer content and adhesion control agents for adhesion management
3Reliability
If thin PVB film with low plasticizer content is used, then penetration resistance improves, but adhesion to glass becomes too high
Solution Approach 1:
The patent adjusts the chemical composition by incorporating adhesion control agents at specific concentrations (0.1-10% by weight) into the thin low-plasticizer PVB film to reduce adhesion to glass surface while maintaining penetration resistance properties
Solution Approach 2:
The patent introduces metal salts as intermediary substances between the PVB film and glass surface, where these adhesion control agents mediate the interaction by reducing direct adhesion between the polymer and glass, thereby enabling penetration resistance without excessive adhesion
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 approach results in laminated glass with improved penetration resistance, as demonstrated by compressive shear strength measurements, effectively passing impact tests like ECE R43, while maintaining reduced adhesion to prevent delamination.
Implementation Method 1
metal ions interact with the glass surface, resulting in a reduced adhesion of the PVB-film to the glass surface
Implementation Method 2
energy uptake by the interlayer in case of a mechanical impact by stretching rather than breaking
Data Source
AI summary
The invention is directed to Laminated glass obtained by laminating at least one film A containing a polyvinyl acetal PA and optionally at least one plasticiser WA and at least one film B containing a polyvinyl acetal PB and at least one plasticiser WB between two glass sheets, characterised in that prior to lamination - the amount of plasticiser WA in film A is less than 16 % by weight - the amount of plasticiser WB in film B is at least 16 % by weight and - film A comprises at least 7 ppm alkali ions.