Plastic Film Hardness via Composite Coating
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Solution Overview
Problem
Existing plastic films for mobile devices lack sufficient hardness and scratch resistance while being prone to curling and cracking, which limits their use as substitutes for glass in display applications.
Innovation Solution
A plastic film comprising a support substrate with a first and second photocrosslinked copolymer coating layer, each containing inorganic fine particles, and a low-reflection coating layer with hollow silica particles, providing enhanced hardness, scratch resistance, and transparency without curling or cracking.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the thickness of the coating layer is increased to improve surface hardness, then the degree of surface hardness increases, but the coating layer becomes more prone to setting shrinkage, wrinkling, curling, and cracking
Solution Approach 1:
The patent uses a composite coating layer comprising a binder resin and inorganic fine particles (silica, alumina, or titanium oxide). This composite structure provides high surface hardness (6H or more) while the inorganic particles reinforce the coating to prevent cracking and improve reliability, resolving the contradiction between hardness and crack resistance.
Solution Approach 2:
The patent optimizes the thickness of the coating layer to 1 μm to 10 μm, finding the optimal balance between achieving sufficient surface hardness and preventing setting shrinkage and curling. This parameter optimization resolves the contradiction by identifying the precise thickness range where both hardness and reliability are maximized.
2Weight of moving object
If a plastic film is used as an alternative to glass to reduce weight, then the weight of mobile devices decreases, but the film lacks sufficient hardness and scratch resistance
Solution Approach 1:
The patent creates a composite coating layer with binder resin and inorganic fine particles that achieves a pencil hardness of 6H or more. This composite structure provides glass-level hardness and scratch resistance while maintaining the lightweight advantage of plastic films, resolving the contradiction between weight reduction and strength enhancement.
3Strength
If a thick coating layer is applied to ensure surface hardness, then hardness is improved, but manufacturing complexity increases due to curling and cracking issues
Solution Approach 1:
The patent specifies a precise coating layer thickness range of 1 μm to 10 μm, which optimizes the balance between achieving sufficient hardness and maintaining manufacturing stability. This parameter control prevents setting shrinkage and curling, making the manufacturing process reliable and easy to execute.
Solution Approach 2:
The composite coating layer with inorganic fine particles provides high hardness within a thin profile (1-10 μm), eliminating the need for thick coatings that cause manufacturing issues. This enables stable production without curling or cracking problems.
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 film achieves a pencil hardness of 6H or more, high scratch resistance, and low reflectivity, making it suitable for use in mobile devices and display instruments without the issues of curling or cracking.
Implementation Method 1
a first photocrosslinked copolymer, and first inorganic fine particles dispersed in the photocrosslinked copolymer
Implementation Method 2
a low-reflection coating layer, formed on the first coating layer
Data Source
AI summary
Disclosed is a plastic film exhibiting excellent physical properties including a high level of hardness, high scratch resistance, and low reflection. Exhibiting a high level of hardness, scratch resistance, impact resistance, low reflectivity, and high transparency, the plastic film can be used as a substitute for a cover plate made of glass or reinforced glass.