Composite Housing Bonding via Acid-Modified Elastomer
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Solution Overview
Problem
There is a lack of an industrially advantageous method for bonding and integrating resin and metal members with high adhesion strength, particularly for electronic device housings that require waterproof and sealing functions in diverse environments.
Innovation Solution
A composite structure comprising a metal member with a fine uneven surface and a thermoplastic resin member, where the thermoplastic resin has a specific hardness and acid value range, and contains thermoplastic elastomers and acid-modified polymers, enhancing bonding strength and elasticity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If conventional elastomers are used for bonding resin and metal members, then sealing function is achieved, but bonding strength and adhesion are insufficient
Solution Approach 1:
The patent modifies the chemical parameters of the elastomer by introducing carboxyl groups through reaction with dicarboxylic acid or dicarboxylic acid anhydride. This chemical modification changes the surface properties and bonding characteristics of the elastomer, enabling strong adhesion to both resin and metal members without requiring additional adhesives.
Solution Approach 2:
The patent creates a composite material system where the elastomer is chemically combined with dicarboxylic acid or dicarboxylic acid anhydride to form a multi-functional sealing component. This composite structure integrates sealing, bonding, and adhesion functions into a single material system, eliminating the need for separate adhesive layers.
2Weight of moving object
If housing groove width and depth are reduced for weight reduction, then device weight decreases, but packing handling and mounting become difficult
Solution Approach 1:
The patent combines the packing material with bonding agents (dicarboxylic acid or dicarboxylic acid anhydride) into a single integrated component. This merging eliminates the need for separate adhesive application steps and allows the packing to be directly mounted into narrow housing grooves while maintaining strong bonding to metal members.
Solution Approach 2:
The patent modifies the physical and chemical parameters of the packing material by incorporating reactive carboxyl groups, which change the material's bonding characteristics. This enables the packing to achieve strong adhesion to metal surfaces even when mounted in narrow, difficult-to-access housing grooves.
3Reliability
If elastomer packing is used for waterproofing, then sealing function is achieved, but adhesion to metal members is insufficient
Solution Approach 1:
The patent chemically modifies the elastomer packing by introducing carboxyl groups through reaction with dicarboxylic acid or dicarboxylic acid anhydride. This parameter change in chemical composition enables the packing to form strong chemical bonds with metal members while maintaining its sealing functionality.
Solution Approach 2:
The packing material itself performs the bonding function to metal members through its modified chemical structure. The carboxyl groups in the elastomer enable direct adhesion to metal surfaces without requiring external adhesives, allowing the packing to serve both sealing and bonding purposes simultaneously.
Data Source
AI summary
A composite structure includes: a metal member; and a thermoplastic resin member bonded to the metal member, in which the metal member has a fine uneven structure at least on a metal surface to which the thermoplastic resin member is bonded, a hardness of the thermoplastic resin member measured by a type A durometer in accordance with JIS K6253 is in a range of equal to or more than A60 and equal to or less than A95, and an acid value of the thermoplastic resin member is equal to or more than 1 mgKOH/g and equal to or less than 100 mgKOH/g. The thermoplastic resin member preferably contains a urethane-based thermoplastic elastomer, an amide-based thermoplastic elastomer, and an acid-modified polyolefin.