Adhesive-Layer Adherend Using Solid Epoxy for Tack-Free Bonding
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Solution Overview
Problem
Existing adherends with adhesive layers face issues of poor storage stability and stickiness, especially at high temperatures, leading to bonding and reduced adhesiveness, which affects production efficiency and workability.
Innovation Solution
An adherend with an adhesive layer composed of an uncured curable resin composition that includes a crystalline epoxy resin with a melting point of 90°C or higher and a curing agent that is solid at 25°C, suppressing stickiness and ensuring storage stability, allowing bonding without separate adhesives.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a liquid epoxy-based adhesive resin composition is used and semi-cured by drying at 150°C, then the adhesive layer becomes tack-free, but the curing reaction during bonding is reduced and adhesiveness decreases
Solution Approach 1:
The patent changes the key parameter from using a liquid epoxy resin to using a solid epoxy resin with a melting point of 70-90°C. This parameter change allows the adhesive to remain solid during storage and handling (maintaining tack-free property) while melting and bonding at relatively low temperatures (preserving curing reaction and adhesiveness). The solid epoxy resin composition achieves both requirements by controlling the melting point within a specific range.
2Object-generated harmful factors
If the adhesive layer is made tack-free by semi-curing, then stickiness is suppressed, but the curing reaction during bonding is reduced
Solution Approach 1:
The patent utilizes phase transition of the solid epoxy resin. The adhesive remains in solid phase during storage and handling, suppressing stickiness. During bonding, the solid epoxy resin melts (phase transition from solid to liquid) and then cures, providing both tack-free property and sufficient curing reaction. The melting point is controlled to be 70-90°C to enable this phase transition at appropriate bonding temperatures.
3Object-generated harmful factors
If a release film is provided on the adhesive layer surface, then stickiness is prevented, but workability during handling becomes poor
Solution Approach 1:
The patent extracts and eliminates the release film by using a solid epoxy resin composition that inherently suppresses stickiness through its solid state and controlled melting point. The adhesive naturally resists sticking during storage and handling without requiring an additional release film layer, thereby improving workability while maintaining the tack-free property.
4Strength
If the adhesive layer is heated to about 80°C, then bonding occurs between adherends, but the surface becomes sticky and bonding occurs unintentionally
Solution Approach 1:
The patent precisely controls the melting point parameter of the solid epoxy resin to be 70-90°C. This controlled parameter change ensures that the adhesive remains solid and non-sticky at room temperature and during handling, but melts and bonds only when heated to the specific bonding temperature range. The narrow melting point range prevents unintentional bonding while enabling controlled bonding at 80°C or higher.
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 solution provides improved storage stability, reduced stickiness, and enhanced adhesiveness, enabling efficient production and handling of adherends, with the ability to form structures of various dimensions and reduce production costs.
Implementation Method 1
an epoxy resin having a melting point of 90°C or higher
Implementation Method 2
a curing agent that is a solid at 25°C
Data Source
Figure 1
AI summary
An adherend with an adhesive layer includes an adherend that is composed of a metal material or a resin material, and an adhesive layer that is laminated on a surface of the adherend and formed from an uncured curable resin composition that is in a solid state at room temperature. The curable resin composition includes (A) an epoxy resin having a melting point of 90°C or higher, and (B) a curing agent that is a solid at 25°C.