Layered Dielectric Heating Adhesive Sheet to Prevent Resin Protrusion
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Solution Overview
Problem
The existing single-layer heat-sensitive adhesive agents used in dielectric heating often protrude from adherend joints, adhering to non-bonded surfaces or the heating device, due to resin melting during pressure application.
Innovation Solution
A high-frequency dielectric heating adhesive sheet with a layered structure comprising a first and second adhesive layer, and an intermediate layer with specific dielectric property ratios, preventing resin protrusion by controlling heat generation and melting.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single-layer heat-sensitive adhesive agent is used for dielectric heating bonding, then the bonding process can be simplified, but the resin protrudes from between stuck portions of adherends during pressure application
Solution Approach 1:
The adhesive sheet is divided into multiple layers with different dielectric properties. The first and second adhesive layers have high dielectric properties and generate heat, while the intermediate layer has low dielectric properties and prevents excessive heat generation, thereby controlling resin melting and preventing protrusion.
Solution Approach 2:
Different regions of the adhesive sheet have different dielectric properties tailored to their specific functions. The outer adhesive layers are designed for heat generation and bonding, while the intermediate layer is designed for heat insulation and protrusion prevention, creating localized functional zones within the sheet.
2Strength
If pressure is applied during dielectric heating bonding to ensure strong adhesion, then bonding strength is improved, but resin is more likely to protrude from bonded surfaces
Solution Approach 1:
The invention changes the dielectric property parameters of different layers to control heat generation distribution. By setting the dielectric property ratios DPM/DP1 and DPM/DP2 to be less than one, the intermediate layer generates less heat under pressure, preventing resin from melting excessively and protruding even when bonding pressure is applied.
3Productivity
If the dielectric property of the adhesive layer is increased to improve heat generation and bonding efficiency, then bonding speed is improved, but resin melting and protrusion become more severe
Solution Approach 1:
The adhesive system is segmented into layers with different dielectric properties. The high dielectric property adhesive layers provide efficient heat generation for fast bonding, while the low dielectric property intermediate layer limits excessive heat generation and resin melting, achieving both high productivity and controlled melting.
Solution Approach 2:
The intermediate layer acts as a mediator between the high dielectric property adhesive layers. It receives and limits heat transmission, preventing the adhesive layers from generating excessive heat that would cause resin melting and protrusion, while still allowing efficient bonding to occur.
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
Prevents resin protrusion during dielectric heating bonding, ensuring secure adhesion without damaging adherends or the heating device, while maintaining effective bonding strength.
Implementation Method 1
a method including performing a dielectric heating treatment, an induction heating treatment, a supersonic welding treatment, a laser welding treatment, or the like with an adhesive agent interposed between adherends
Implementation Method 2
a first adhesive layer containing a first thermoplastic resin, the second adhesive layer containing a second thermoplastic resin
Data Source
AI summary
A high-frequency-dielectric-heating-adhesive-sheet includes: a first adhesive layer containing a first thermoplastic resin; a second adhesive layer containing a second thermoplastic resin; and an intermediate layer, a ratio DPM/DP1 of dielectric property DPM of the intermediate layer to dielectric property DP1 of the first adhesive layer and a ratio DPM/DP2 of the dielectric property DPM of the intermediate layer to dielectric property DP2 of the second adhesive layer are each less than one, and the dielectric property DP1, the dielectric property DP2, and the dielectric property DPM are values of dielectric property (tanδ/ε′r) of the first adhesive layer, the second adhesive layer, and the intermediate layer, respectively. tanδ denotes a dielectric dissipation factor at 23 degrees C. and a frequency of 40.68 MHz and ε′r denotes a relative permittivity at 23 degrees C. and the frequency of 40.68 MHz.