Colored Primer Composition for Automotive Glass Bonding
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Solution Overview
Problem
The existing methods for bonding transparent substrates in automotive vehicle window assemblies, particularly those with darkened or opaque peripheral bands, face issues such as defects and scrap due to the need for firing ceramic enamels, and there is a need for improved weatherability and bonding systems that can match vehicle colors.
Innovation Solution
A method involving a primer composition with an isocyanate functional prepolymer derived from aliphatic polyisocyanate and polyol, partially reacted with secondary aminosilane, and a colorant, applied to a transparent substrate without ceramic enamel, along with a urethane adhesive, to achieve strong bonding and color matching, while ensuring weatherability and adhesive integrity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If ceramic enamel is applied and fired to create darkened or opaque peripheral bands on glass substrates, then the bonding strength and tenacity of the ceramic enamel to glass is improved, but defects occur during firing resulting in scrap of the coated glass substrate
Solution Approach 1:
The invention removes the problematic ceramic enamel firing step entirely from the process. Instead of applying and firing ceramic enamel to create darkened or opaque peripheral bands, the patent uses a primer composition with colorants that can be applied without high-temperature firing, thereby eliminating the defects associated with the firing process while maintaining the desired aesthetic and bonding functions.
Solution Approach 2:
The invention changes the processing parameters from high-temperature firing (required for ceramic enamel) to lower temperature application and curing of a primer composition. This parameter change allows the use of alternative materials (primer with colorants instead of ceramic enamel) that achieve the same visual effect without the harmful high-temperature process that causes defects.
2Ease of manufacture
If a primer composition with colorant is applied to match vehicle color, then color matching and aesthetic appearance is improved, but the complexity of the primer formulation increases
Solution Approach 1:
The primer composition is designed to perform multiple functions simultaneously: it provides adhesion promotion, corrosion protection, and color matching in a single formulation. By incorporating colorants directly into the primer, the system eliminates the need for separate ceramic enamel application and firing steps, as well as separate primer and topcoat applications, thereby simplifying the overall manufacturing process despite the enhanced functionality of the primer itself.
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 provides a robust, weather-resistant bond that withstands environmental testing and lap shear testing without adhesive failure, ensuring cohesive failure and matching vehicle colors, thus reducing scrap and improving assembly efficiency.
Implementation Method 1
an isocyanate functional prepolymer derived from the reaction of an aliphatic polyisocyanate and a polyol, at least partially reacted with an amino group of a secondary aminosilane
Implementation Method 2
an isocyanate functional prepolymer derived from the reaction of an aliphatic polyisocyanate and a polyol
Data Source
AI summary
A method for bonding a substantially transparent substrate within an opening of a structure, including steps of applying to a substantially transparent substrate such as glass a primer composition that includes a colorant; applying an adhesive to the structure defining the opening; and installing the substantially transparent substrate within the opening, wherein the resulting installed substrate is substantially free of any ceramic enamel. Also disclosed are assemblies that include a primer composition that includes a colorant and is substantially free of any ceramic enamel.