Pressure-Sensitive Adhesive Composition for Flexible Devices
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Solution Overview
Problem
Developing a pressure-sensitive adhesive composition for flexible devices that can effectively follow repeated deformation and recovery while maintaining suitable elastic modulus, recovery rate, and peel force, and excluding the need for a polarizing plate by adjusting transmittance.
Innovation Solution
A pressure-sensitive adhesive composition with a low storage elastic modulus at −20° C. and high recovery rate, incorporating an acrylic copolymer with specific monomer units, such as alkyl (meth)acrylate and polar functional group-containing units, and a cross-linking agent, which forms a cross-linked structure to achieve the desired properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the elastic modulus of the pressure-sensitive adhesive is lowered to effectively follow repeated deformation, then the ability to follow deformation is improved, but the recovery rate and cuttability deteriorate
Solution Approach 1:
The patent applies parameter changes by carefully controlling the storage elastic modulus within a specific range (10^5 to 10^6 Pa at -20°C) and adjusting the glass transition temperature (Tg) to -50°C to -30°C. These precise parameter adjustments enable the adhesive to follow deformation effectively while maintaining adequate recovery rate and cuttability, resolving the contradiction between adaptability and reliability.
Solution Approach 2:
The patent uses composite materials by formulating a pressure-sensitive adhesive composition containing specific components: acrylic copolymer (including methyl methacrylate and butyl acrylate units), rubber particles, and plasticizer. This composite structure combines the rigidity needed for recovery with the flexibility needed for deformation following, simultaneously achieving both adaptability and reliability.
2Ease of manufacture
If the elastic modulus is increased to improve cuttability and workability, then the ease of manufacture is improved, but the ability to follow deformation and peel force are reduced
Solution Approach 1:
The patent resolves this contradiction by optimizing the storage elastic modulus to a specific intermediate range (10^5 to 10^6 Pa at -20°C), which is neither too low nor too high. This precise parameter control ensures the adhesive has sufficient stiffness for good cuttability and workability while maintaining enough flexibility to follow deformation effectively during device folding.
3Illumination intensity
If a dye is added to adjust the transmittance of the pressure-sensitive adhesive layer, then the transmittance is improved, but the viscoelastic properties and elastic modulus are affected
Solution Approach 1:
The patent resolves this contradiction by controlling the dye content within a specific range (0.1 to 5 parts by weight per 100 parts by weight of pressure-sensitive adhesive) and adjusting the glass transition temperature to -50°C to -30°C. These parameter adjustments ensure the adhesive maintains adequate transmittance for polarizing plate omission while preserving the viscoelastic properties needed for deformation following and recovery.
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 composition effectively responds to deformation and recovery without defects, maintains excellent cuttability and workability, and achieves the required peel force and transmittance for flexible devices, allowing the omission of polarizing plates.
Implementation Method 1
incorporating an acrylic copolymer with specific monomer units, such as alkyl (meth)acrylate and polar functional group-containing units, and a cross-linking agent, which forms a cross-linked structure to achieve the desired properties
Implementation Method 2
The pressure-sensitive adhesive composition with a low storage elastic modulus at -20° C. and high recovery rate
Data Source
AI summary
A pressure-sensitive adhesive composition for forming a pressure-sensitive adhesive layer, which is applied to a flexible device, thereby effectively responding to repeated deformation and recovery, causing no defects (for example, observation of deformation traces and the like) before and after deformation, having excellent cuttability and workability, causing no lifting, delamination, and/or bubble generation, and exhibiting a transmittance at a level capable of omitting a polarizing plate is provided.