Optical Pressure-Sensitive Adhesive for Thermal Rework
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Solution Overview
Problem
It is challenging to separate large-sized, complicated-shaped components like cover glass from organic electroluminescent display panels without damage, as existing methods require high bond strength for reliable adhesion and low bond strength for easy separation, which is difficult to achieve simultaneously.
Innovation Solution
An optical pressure-sensitive adhesive composition with specific release forces, storage moduli, moisture content, and chromaticity variation is developed, allowing for easy removal at high temperatures while maintaining bonding reliability, using a composition that provides a release force of 4.0 N/20 mm or less and a storage modulus of 0.1 ×10^5 Pa or greater.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the bond strength of the pressure-sensitive adhesive layer is increased to ensure reliable adhesion during use, then the bonding reliability is improved, but the ease of separation at high temperature deteriorates
Solution Approach 1:
The patent applies parameter changes by formulating the pressure-sensitive adhesive composition with specific components (polymer, monofunctional acrylate, crosslinking agent) and ratios to achieve a release force of 4.0 N/20 mm or less at 100°C. This controlled parameter change allows the adhesive to maintain strong bonding during use while enabling easy separation at elevated temperatures, resolving the contradiction between bonding reliability and ease of separation.
2Ease of operation
If a metal wire cutting process is used to separate the pressure-sensitive adhesive layer, then the separation can be achieved, but the component such as cover glass may be damaged or deformed
Solution Approach 1:
The patent replaces the mechanical wire cutting system with a thermal separation system. By controlling the release force characteristics of the pressure-sensitive adhesive composition, the cover glass can be separated from the display panel through controlled heating to 100°C, eliminating the need for mechanical cutting and preventing damage or deformation to the glass component.
3Ease of operation
If the release force is reduced to enable easy removal at high temperature, then the heating reworkability is improved, but the bonding reliability during use deteriorates
Solution Approach 1:
The patent uses a composite pressure-sensitive adhesive composition comprising a polymer, monofunctional acrylate, and crosslinking agent. This composite formulation creates a material with dual characteristics: strong bonding reliability during normal use conditions and low release force (4.0 N/20 mm or less) at elevated temperatures, thereby achieving both heating reworkability and bonding reliability simultaneously.
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 adhesive composition enables the separation of cover glass from organic electroluminescent display panels without damage or deformation, ensuring heating reworkability and durability, allowing for the reuse of components.
Implementation Method 1
the pressure-sensitive adhesive layer is heated to a high temperature higher than the service temperature to lower the bond strength of the pressure-sensitive adhesive layer to the component such as cover glass
Implementation Method 2
an optical pressure-sensitive adhesive composition that provides such heating reworkability that a pressure-sensitive adhesive layer made from the composition can be easily removed from a component such as cover glass at a temperature higher than the service temperature
Data Source
Figure 1~2
AI summary
Provided is an optical pressure-sensitive adhesive composition that gives a pressure-sensitive adhesive layer having such heating reworkability as to be easily removed from a component such as cover glass at a temperature higher than the service temperature of an image display device. The optical pressure-sensitive adhesive composition of the present invention gives a release force X of 4.0 N/20 mm or less, where the release force X is a release force determined by applying a film to a glass plate through a pressure-sensitive adhesive layer made from the optical pressure-sensitive adhesive composition, and puling the film at a temperature of 100°C, a peel angle of 180 degrees, and a tensile speed of 50 mm/min.