Multilayer Adhesive Tape Step Coverage and Reworkability
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Solution Overview
Problem
Adhesive tapes used in electronic devices face challenges such as poor durability at high temperatures, residue issues during removal, and bubble formation when applied to surfaces with step differences, which affect their performance and reworkability.
Innovation Solution
A multilayer adhesive tape design featuring a first and second outer adhesive layer, each incorporating a cured product of a high molecular weight prepolymer and a low molecular weight prepolymer, optimized for weight average molecular weights and glass transition temperatures to enhance step coverage, adhesive strength, and reworkability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If adhesive tape is used with high adhesive strength to ensure durable attachment, then adhesive strength is improved, but residue and damage occur during removal making rework difficult
Solution Approach 1:
The adhesive tape is divided into three distinct layers: a first outer adhesive layer, an intermediate layer, and a second outer adhesive layer. Each layer serves different functions - the outer layers provide strong adhesion while the intermediate layer enables clean removal, thus resolving the contradiction between adhesive strength and reworkability through functional segmentation
Solution Approach 2:
Different layers of the adhesive tape have different local properties: the outer adhesive layers are designed with high adhesive strength for durable attachment, while the intermediate layer is designed with specific molecular weight characteristics that allow clean removal without residue. This local differentiation of material properties enables both strong adhesion and easy rework
2Manufacturing precision
If adhesive tape is applied to members with step difference to achieve complete coverage, then step coverage is improved, but delay bubbles occur due to adhesive recovery
Solution Approach 1:
The patent optimizes the weight average molecular weight of the adhesive composition within a specific range (10,000-1,500,000 g/mol) to balance adhesion and recovery characteristics. This parameter control allows the adhesive to adequately flow into step differences for complete coverage while maintaining sufficient recovery resistance to prevent delay bubbles
Solution Approach 2:
The adhesive tape uses a composite structure with multiple layers having different material compositions. The outer adhesive layers are formulated with specific molecular weight ranges to provide both good step coverage and resistance to adhesive recovery, eliminating delay bubbles while maintaining complete coverage over stepped surfaces
3Reliability
If adhesive tape is designed for high temperature durability to withstand thermal fluctuation, then durability is improved, but adhesive performance becomes demanding and complex
Solution Approach 1:
The patent specifies precise molecular weight parameters for the adhesive composition (weight average molecular weight between 10,000-1,500,000 g/mol) to achieve high temperature durability. By controlling these physical parameters, the invention attains thermal stability without requiring complex chemical formulations or multi-component systems
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 multilayer adhesive tape demonstrates improved adhesive strength, reduced residue during removal, and enhanced durability at high temperatures and humidity, while maintaining excellent step coverage and reworkability.
Implementation Method 1
a first outer adhesive layer; an intermediate adhesive layer; and a second outer adhesive layer, in which at least one of the first outer adhesive layer and the second outer adhesive layer includes a cured product of an outer adhesive composition including a high molecular weight prepolymer
Implementation Method 2
a cured product of an outer adhesive composition including a high molecular weight prepolymer having a weight average molecular weight of 100,000 g/mol or more and 1,500,000 g/mol or less and a low molecular weight prepolymer having a weight average molecular weight of 1,000 g/mol or more and 80,000 g/mol or less
Data Source
AI summary
A multilayer adhesive tape is provided, including: a first outer adhesive layer; an intermediate adhesive layer; and a second outer adhesive layer sequentially. At least one of the first outer adhesive layer and the second outer adhesive layer includes a cured product of an outer adhesive composition including a high molecular weight prepolymer having a weight average molecular weight of 100,000 g/mol or more and 1,500,000 g/mol or less and a low molecular weight prepolymer having a weight average molecular weight of 1,000 g/mol or more and 80,000 g/mol or less.