Automotive Resin Glazing Refinish Coating System
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Solution Overview
Problem
Existing automotive resin glazing refinish coating systems struggle to form a tight bond with existing silicone hard coat layers, leading to uneven appearances and cumbersome repair processes, especially when dealing with cracks and thickness variations, due to the difficulty in directly applying a new silicone layer on cured surfaces.
Innovation Solution
A refinish coating system comprising an intermediate coating composition with silica and a reactive siloxane compound, followed by a room temperature-curable topcoat coating composition containing a phosphoric acid-based cure catalyst, which allows for direct application and curing on the silicone hard coat layer to achieve equivalent appearance, transparency, mar resistance, and adhesion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a new silicone layer is directly applied on a cured silicone hard coat layer, then the repair process becomes simpler and faster, but the bond between layers is weak and the appearance becomes uneven
Solution Approach 1:
The patent introduces a primer layer as an intermediary substance between the existing cured silicone hard coat layer and the new silicone layer. This primer layer contains silane coupling agents that chemically bond to both the existing silicone surface and the new silicone coating, creating a strong intermediate bonding interface that ensures uniform appearance and eliminates the weakness of direct application
Solution Approach 2:
The patent modifies the chemical parameters of the primer layer by incorporating specific silane coupling agents and controlling the curing conditions (temperature, humidity, time). These parameter changes enable the primer to form a chemically active surface that enhances adhesion between layers, resolving the bond quality issue while maintaining process efficiency
2Strength
If a primer layer is formed to enable tight bonding, then adhesion improves, but the process becomes more cumbersome and time-consuming
Solution Approach 1:
The patent combines the primer layer application and the silicone hard coat layer application into a more integrated process. The primer is applied in a thin layer that quickly cures, and the silicone coating is applied immediately afterward while the primer is still slightly tacky, reducing the overall number of discrete steps and drying times while maintaining strong adhesion
3Ease of repair
If refinish coating is applied to defective portions, then repair is achieved, but the cured state differs from the original coating resulting in poor luster appearance
Solution Approach 1:
The patent carefully controls the curing parameters (temperature, humidity, time) and composition of the refinish coating to match the original coating's cured state. By adjusting these parameters, the refinish coating achieves the same luster, transparency, and surface properties as the original coating, eliminating visual discrepancies
Solution Approach 2:
The patent applies the refinish coating specifically to the defective portions while using the primer to ensure seamless integration with the surrounding original coating. The local application combined with the bonding primer creates a uniform appearance where the repair area blends indistinguishably with the rest of the surface
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 system effectively repairs damage areas by forming a two-layer coating that matches the original silicone hard coat layer in appearance and properties, simplifying the repair process and eliminating the need for a primer layer, thereby reducing operational complexity and ensuring a uniform finish.
Implementation Method 1
intermediate coating composition comprising (A) 100 parts by weight of a reactive siloxane compound and (B) 1 to 50 parts by weight of silica
Implementation Method 2
topcoat coating composition to be coated thereon, the topcoat coating composition comprising (C) 1 to 25 parts by weight of an alkoxysilane having a UV-absorbing functional group, (D) 20 to 70 parts by weight of a multifunctional alkoxysilane, (E) 20 to 70 parts by weight of a reactive siloxane compound, (F) 1 to 50 parts by weight of colloidal silica, and (G) 0.5 to 20 parts by weight of phosphoric acid
Implementation Method 3
alkoxysilane having a UV-absorbing functional group, (D) 20 to 70 parts by weight of a multifunctional alkoxysilane
Implementation Method 4
alkoxysilane having a UV-absorbing functional group
Data Source
AI summary
Disclosed is a method for repairing a damaged area of a silicone hard-coat layer on an automotive resin glazing substrate by applying an intermediate coating composition (I) to the damaged area and applying a topcoat coating composition (II) to the intermediate coating composition. The intermediate coating composition (I) contains (A) a reactive siloxane compound and (B) silica. The topcoat coating composition (II) contains (C) an alkoxysilane having a UV-absorbing functional group, (D) a multifunctional alkoxysilane, (E) a reactive siloxane compound, (F) colloidal silica, and (G) phosphoric acid. The method forms a coating having the same appearance and physical properties as the underlying silicone hard-coat layer.