Sheet Adhesive Low-Temperature Bonding Reactive Layer
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Solution Overview
Problem
Conventional sheet adhesives face challenges in achieving high adhesiveness at low temperatures (20 to 90°C) while maintaining softness and preventing squeeze-out during bonding, which can damage substrates and affect adhesive strength.
Innovation Solution
A sheet adhesive comprising a substrate layer with a urethane elastomer and epoxy resin, and a reactive layer formed with an amine or phenol compound, allowing for low-temperature bonding and improved squeeze-out characteristics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If heating at 100°C or more is applied to activate the reactive layer, then adhesion can be achieved, but the adherend is heated and damaged
Solution Approach 1:
The patent changes the temperature parameter from conventional high temperature (100°C or more) to low temperature (20-90°C) by modifying the reactive layer composition. The reactive layer contains a specific compound (component C) that enables curing at lower temperatures, thus achieving adhesion without damaging the adherend with excessive heat
Solution Approach 2:
The patent uses a composite structure with a substrate layer (component A: polyolefin resin) and a reactive layer (component B: epoxy resin, component C: curing agent). This composite material system allows the adhesive to function at low temperatures while maintaining strong bonding, resolving the contradiction between adhesion strength and heat damage prevention
2Strength
If conventional adhesive is used with heating or press-bonding, then bonding can be achieved, but fluidity is generated in substrate layer causing dimension change
Solution Approach 1:
The patent changes the bonding temperature parameter to low temperature (20-90°C), which prevents the substrate layer from becoming fluid and maintaining dimensional stability. The low-temperature curing process avoids melting or deforming the substrate while still achieving strong bonding through the reactive layer
Solution Approach 2:
The patent applies different properties to different layers: the substrate layer maintains its structural integrity and dimensional stability, while the reactive layer provides the bonding function. This local differentiation allows bonding strength to be achieved without compromising the substrate's dimensional precision
3Device complexity
If reactive layer is made as a single layer, then structure is simple, but reaction proceeds with time causing lowered adhesive strength
Solution Approach 1:
The patent applies the reactive layer to the adherend surface in advance, before the substrate layer is bonded. The reactive layer contains component C (curing agent) that reacts with component B (epoxy resin) upon contact, initiating curing immediately at the bonding interface. This preliminary application ensures strong adhesion develops right at the interface rather than degrading over time
Solution Approach 2:
The patent segments the adhesive system into two functional layers: a substrate layer providing structural support and a reactive layer providing bonding function. This segmentation allows the reactive layer to be optimized for immediate chemical reaction and adhesion at the interface, preventing strength loss over time while keeping the overall structure relatively simple
4Strength
If sheet is made as multiple layers to improve adhesion, then adhesive strength increases, but sheet becomes thick limiting its use
Solution Approach 1:
The patent segments the adhesive into two distinct layers with specific thickness ratios: substrate layer (thickness a) and reactive layer (thickness b), where a ≥ b. This segmentation concentrates the bonding function in the thin reactive layer at the interface, achieving strong adhesion without requiring excessive overall thickness. The substrate layer provides structural support while the reactive layer provides chemical bonding
Solution Approach 2:
The patent uses a composite material system where the substrate layer (polyolefin resin) and reactive layer (epoxy resin + curing agent) work together synergistically. This composite structure achieves high adhesive strength through chemical bonding in the reactive layer while maintaining reasonable overall thickness, avoiding the need for excessively thick multi-layer constructions
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 exhibits high adhesiveness and prevents squeeze-out during bonding, maintaining strength and softness, even at low temperatures, thus suitable for various applications including electric and electronic machinery tools.
Implementation Method 1
a reactive layer formed with a liquid agent including 45% by mass or less of component (C): an amine compound and/or phenol compound
Implementation Method 2
a substrate layer including component (A): a urethane elastomer and component (B): an epoxy resin
Data Source
AI summary
It has conventionally been difficult to achieve a sheet adhesive which adheres in a low temperature (from 20 to 90° C.), and has both of softness and high adhering strength. The present invention realizes a sheet adhesive capable of adhering in a low temperature (from 20 to 90° C.) which exhibits a high adhesiveness in spite of being a soft sheet of thin film, by forming a simulated multiple layer by using an elastomer as a substrate layer, and by forming a reactive layer by means of spraying or application.A sheet adhesive including a substrate layer and a reactive layer, wherein the substrate layer includes a component (A) and a component (B) below, and the reactive layer is formed with a liquid agent including a component (C) below in an amount of from 0.01% by mass to 45% by mass,component (A): a urethane elastomer,component (B): an epoxy resin,component (C): an amine compound and/or phenol compound.