Coating Composition Hardness Flexibility Balance
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Solution Overview
Problem
Existing coatings for electronic device screens, such as plastic sheets, face challenges in achieving a balance between hardness and flexibility while maintaining transparency and high elastic modulus, as they are prone to scratching and indentation.
Innovation Solution
A coating composition comprising a matrix mixture of urethane multi(meth)acrylates, non-urethane multi(meth)acrylates, mono(meth)acrylates, and zirconia particles with specific size and distribution characteristics, applied to a substrate and cured to form a hard yet flexible film.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a plastic sheet is used as the surface of the display screen, then flexibility is provided, but the surface is prone to damage by scratching or indentation
Solution Approach 1:
The invention uses a composite coating system combining organic polymers (urethane (meth)acrylates and other multi(meth)acrylates) with inorganic zirconia nanocrystals. This composite structure provides both the flexibility of the organic matrix and the hardness/scratch resistance of the inorganic nanocrystals, resolving the contradiction between flexibility and scratch resistance.
2Strength
If metal oxide nanocrystals are added to improve hardness, then scratch resistance is enhanced, but transparency and elastic modulus may be compromised
Solution Approach 1:
The invention carefully controls the particle size parameter of zirconia nanocrystals (1 nm to 100 nm, preferably 1 nm to 50 nm, more preferably 1 nm to 20 nm) and their concentration (0.1 wt% to 10 wt%). By optimizing these parameters, the coating achieves enhanced hardness while maintaining transparency, as the nanoscale particles are small enough to not scatter visible light significantly.
Solution Approach 2:
The zirconia nanocrystals are distributed uniformly throughout the polymer matrix at controlled concentrations. This uniform local distribution ensures that hardness enhancement is achieved throughout the coating without creating regions that would scatter light and reduce overall transparency.
3Illumination intensity
If zirconia particles with narrow size distribution are used, then transparency is maintained, but manufacturing precision requirements increase
Solution Approach 1:
The invention specifies a breadth parameter (BP) of 5 nm or less for the zirconia particle size distribution, with preferred ranges of 1 nm to 100 nm, more preferably 1 nm to 50 nm. This controlled parameter range achieves transparency while the patent acknowledges and addresses the manufacturing challenge by providing clear specifications for particle size control.
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 coating composition provides enhanced hardness and flexibility, maintaining transparency and high elastic modulus, effectively protecting against scratches and indentations while ensuring optical clarity.
Implementation Method 1
a coating composition comprising (a) a matrix mixture... (b) zirconia... wherein said zirconia is in the form of a collection of zirconia particles having number-average diameter of 100 nm or less; wherein said collection of zirconia particles has a distribution of diameters that has a breadth parameter (BP)... of 5 nm or less
Implementation Method 2
a matrix mixture... comprising (i) 30% to 95% one or more urethane multi(meth)acrylates having exactly two (meth)acrylic functional groups... (ii) 4% to 50% one or more non-urethane multi(meth)acrylate having three or more (meth)acrylic functional groups... (iv) 1% to 10% one or more initiators
Data Source
AI summary
Provided is a coating composition comprising (a) a matrix mixture, comprising (i) one or more urethane multi(meth)acrylates (ii) one or more non-urethane multi(meth)acrylates (iii) optionally one or more mono(meth)acrylates (iv) one or more initiators; (b) zirconia,; and wherein the weight ratio of (a) to (b) is from 0.06:1 to 2.8:1, and wherein the amount of (a) plus the amount of (b) is 1% to 100% by weight based on the weight of said coating composition. Also provided is a coated article formed by a process comprising (A) applying a layer of the coating composition to a surface of a substrate, (B) removing said solvent from said layer of the coating composition, and (C) curing, or allowing to cure, said layer of the coating composition.