Expandable Adhesive Sheet for Easy Insertion and Heat-Resistant Bonding
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Solution Overview
Problem
Conventional adhesive sheets struggle to achieve both temporary fixability at room temperature and heat resistance, leading to positional deviation and contamination issues during bonding, especially in high-temperature environments.
Innovation Solution
An adhesive sheet with a thermally expandable thermosetting adhesive layer and patterned sticky parts on one face for temporary fixability, and a low-adhesive second face for easy insertion, expanding and curing to provide strong bonding under high temperatures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If an adhesive sheet with high initial adhesiveness is used to achieve temporary fixability at room temperature, then the member can be temporarily fixed, but the member cannot be easily inserted into the cavity without causing positional deviation
Solution Approach 1:
The adhesive sheet applies local quality by providing sticky parts only at specific locations (first principal face) while keeping other areas non-sticky (second principal face). This allows the sticky parts to provide temporary fixation at the bonding position without causing adhesion that would prevent easy insertion during the insertion process.
Solution Approach 2:
The adhesive sheet is segmented into functionally different regions: a first principal face with sticky parts for temporary fixation and a second principal face without sticky parts for easy insertion. This segmentation allows each region to perform its specific function independently, resolving the contradiction between temporary fixability and ease of insertion.
2Ease of operation
If conventional adhesive sheets are used to maintain ease of insertion, then the member can be easily inserted, but positional deviation occurs and contamination happens due to adhesive adhesion outside the cavity
Solution Approach 1:
By concentrating the adhesive properties to specific sticky parts on the first principal face, the adhesive sheet ensures that adhesion occurs only at the intended bonding location. This prevents adhesive adhesion outside the cavity, eliminating contamination and positional deviation while maintaining ease of insertion through the non-sticky second principal face.
3Strength
If an adhesive sheet with high heat resistance is used to achieve strong bonding under high temperatures, then excellent adhesive strength is obtained, but the sheet cannot be easily inserted and temporarily fixed at room temperature
Solution Approach 1:
The adhesive sheet uses local quality by equipping only the first principal face with sticky parts for room temperature temporary fixation, while the second principal face remains non-sticky for easy insertion. The thermally expandable thermosetting adhesive layer provides high-temperature bonding strength after expansion, resolving the contradiction between heat resistance and ease of room temperature handling.
Solution Approach 2:
The adhesive sheet utilizes parameter changes through thermal expansion. The thermally expandable thermosetting adhesive layer transitions from a compact state at room temperature (allowing easy insertion) to an expanded state at high temperatures (providing strong bonding). This parameter change resolves the contradiction between ease of insertion and high-temperature adhesive strength.
4Strength
If liquid adhesive is used to bond the member, then strong bonding can be achieved, but the process becomes complicated requiring viscosity adjustment and filling amount control, and contamination occurs
Solution Approach 1:
The invention replaces the liquid adhesive application process with a pre-formed adhesive sheet containing a thermally expandable thermosetting adhesive layer. This substitution eliminates the need for viscosity adjustment and filling amount control, simplifying the process while maintaining strong bonding through thermal expansion and curing.
Solution Approach 2:
The adhesive sheet performs self-service by containing the adhesive material in a pre-measured, pre-positioned format. The thermally expandable thermosetting adhesive layer automatically expands to fill the cavity and bond the members together when heated, eliminating the need for complex process control and preventing contamination from adhesive overflow.
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 sheet ensures temporary fixability at room temperature, easy insertion, and maintains excellent adhesive strength even under high temperatures, preventing positional deviation and contamination.
Implementation Method 1
a thermally expandable thermosetting adhesive layer and a plurality of sticky parts provided on a first principal face of the thermally expandable thermosetting adhesive layer
Implementation Method 2
the adhesive sheet, before expansion, achieving both temporary fixability at room temperature and ease of insertion when inserting one member into a cavity of another member and, after expansion, maintaining excellent adhesive strength to enable the members to be firmly bonded together even under high temperature environments
Data Source
AI summary
An adhesive sheet expandable by heating is provided. The adhesive sheet, before expansion, achieve temporary fixability at room temperature and ease of insertion when inserting one member into a cavity of another member. The adhesive sheet, after expansion, maintains excellent adhesive strength to enable the members to be firmly bonded together even under high temperature environments. An adhesive sheet includes a first principal face and a second principal face opposite to each other. The first principal face includes a thermally expandable thermosetting adhesive layer and a plurality of sticky parts provided on a first principal face of the thermally expandable thermosetting adhesive layer in a patterned manner. The second principal face includes the thermally expandable thermosetting adhesive layer forming the first principal face of the adhesive sheet or another thermally expandable thermosetting adhesive layer. An article including the adhesive sheet, and a method for producing the same are also provided.