Tetrafunctional Polyurethane Acrylate Coating for PMMA Adhesion
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Solution Overview
Problem
The surface hardness of PMMA films is insufficient, leading to easy scratching and affecting the optical properties of display panels, while traditional hardened coating layers on PMMA films often suffer from poor adhesion due to high internal stress.
Innovation Solution
A coating film comprising a tetrafunctional polyurethane acrylate oligomer with a specific molecular structure, nano-silica particles, and photoinitiators is applied to the PMMA film, enhancing intermolecular interactions through hydrogen bonding and cross-linking, thereby improving adhesion and mechanical properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a hardened coating layer is formed directly on the PMMA film surface, then the surface hardness is improved, but the adhesion between the coating layer and PMMA film deteriorates due to large internal stress
Solution Approach 1:
The patent introduces a polyurethane oligomer layer as an intermediary between the PMMA film and the hardened coating layer. This intermediate layer has moderate functionality that bridges the low-polarity PMMA surface and the high-functionality hardened coating material, reducing internal stress and improving adhesion while still allowing the outer hardened layer to provide sufficient surface hardness.
Solution Approach 2:
The patent changes the functionality parameter of the coating material from high (direct hardened coating) to moderate (polyurethane oligomer with functionality of 2-4), which reduces the internal stress and improves adhesion to the PMMA substrate while maintaining the ability to form a hardened protective layer.
2Reliability
If the PMMA film surface is left untreated, then the adhesion is maintained, but the surface hardness is insufficient and the film is easily scratched
Solution Approach 1:
The patent segments the coating system into multiple functional layers: the original PMMA film layer and a new polyurethane oligomer hardened coating layer. This segmentation allows each layer to perform its specialized function - the PMMA provides substrate integrity while the polyurethane oligomer layer provides enhanced surface hardness and scratch resistance.
Solution Approach 2:
The patent creates a composite structure by combining PMMA film with a polyurethane oligomer hardened coating layer. This composite material system integrates the optical properties of PMMA with the mechanical hardness and adhesion properties of the polyurethane oligomer, achieving both good adhesion and sufficient surface hardness.
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 proposed coating film significantly enhances the adhesion of the hardened layer to the PMMA film, reducing the risk of defects like shrinkage, warping, or cracking, while also improving the mechanical properties and durability of the display panel.
Implementation Method 1
more N—H moieties are contained in the molecular structure of the coating film and may form hydrogen bonds with O atoms of the ester groups of PMMA, thereby enhancing intermolecular interaction between the coating film and the PMMA film
Implementation Method 2
A coating film comprising a tetrafunctional polyurethane acrylate oligomer with a specific molecular structure, nano-silica particles, and photoinitiators is applied to the PMMA film, enhancing intermolecular interactions through hydrogen bonding and cross-linking
Data Source
AI summary
The present disclosure provides a coating film and a display panel, wherein the coating film includes a tetrafunctional polyurethane acrylate oligomer having a structure as shown below. The coating film according to the present disclosure can enhance the adhesion force to a polymethyl methacrylate film.