Foamed Rubber Gasket Material for Electronic Sealing
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Solution Overview
Problem
Current gasket materials fail to provide effective sealing under low surface pressure and high temperature conditions, especially in electronic circuits where corrosion resistance and prevention of axial load reduction are critical, and they often suffer from plastic flow and fluid permeation due to inadequate cell structure and sulfur-based vulcanization.
Innovation Solution
A gasket material with a foamed rubber layer having a closed cell structure, formed on a metal plate via an adhesive layer, using carboxyl group-modified nitrile rubber crosslinked with an epoxy compound and accelerated by 2-ethyl-4-methylimidazole, achieving an expansion ratio of 2.0 to 3.0 and enhanced thermal resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a thick rubber layer (70 μm or more) is used before foaming to achieve high expansion ratio (2 or more), then sealing capability against high surface roughness and blowholes is improved, but the foamed rubber layer is crushed under high temperature and pressure, leading to reduced axial loads of bolts
Solution Approach 1:
The patent optimizes the thickness of the rubber layer before foaming to a specific range (15-50 μm) and controls the expansion ratio (2-4) to achieve the desired balance between sealing capability and structural integrity, preventing crushing under high temperature and pressure while maintaining effective sealing
Solution Approach 2:
The patent uses a composite structure consisting of a metal plate with a foamed rubber layer laminated on it, where the rubber layer contains specific additives and crosslinking agents to enhance its resistance to compression and maintain axial load under high temperature and pressure conditions
2Stability of the object's composition
If a foamed rubber layer with closed cells is used to prevent shrinkage at low temperature, then axial load stability is improved, but small expansion ratio has small effect on sealing blowholes and imperfect crushing leads to stress relaxation under low sealing surface pressure
Solution Approach 1:
The patent optimizes the expansion ratio to a specific range (2-4) and controls the cell structure to achieve a balance between maintaining axial load stability and ensuring effective sealing of blowholes, while preventing stress relaxation under low sealing surface pressure through proper thickness control
3Reliability
If conventional sulfur-vulcanized rubber is used to achieve good elasticity and compression recovery, then sealing capability is improved, but corrosion of electronic circuits occurs
Solution Approach 1:
The patent removes sulfur and sulfur-containing additives from the rubber composition to eliminate corrosion of electronic circuits, while maintaining the desired elasticity and compression recovery properties through alternative compounding and processing methods
Solution Approach 2:
The patent modifies the rubber composition by eliminating sulfur vulcanization and using alternative crosslinking systems or physical crosslinking methods to achieve the required mechanical properties without corrosive byproducts
4Strength
If a foamed rubber layer with large expanding cell diameters and mixed closed/open cells is used, then compression recovery property is improved, but fluids permeate through open cells causing large stress relaxation and deterioration of sealing properties
Solution Approach 1:
The patent optimizes foaming parameters to achieve a controlled cell structure with predominantly closed cells and appropriate cell diameter distribution, preventing fluid permeation and stress relaxation while maintaining adequate compression recovery for effective sealing
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 a tight seal under low surface pressure, prevents axial load reduction, and offers improved corrosion resistance and thermal stability, reducing plastic flow and fluid permeation, making it suitable for electronic components.
Implementation Method 1
a foamed rubber layer is formed by thermal expansion of a low-boiling point hydrocarbon expansion agent in microcapsule-like particles
Implementation Method 2
the foamed rubber layer comprises a carboxyl group-modified nitrile rubber, and the foamed rubber layer is crosslinked with an epoxy compound
Implementation Method 3
a foamed rubber layer having a closed cell structure is formed, via an adhesive layer, on at least one side of a metal plate
Data Source
AI summary
The purpose of the present invention is to provide a gasket material that is capable of preventing corrosion caused by sulfur element, can be used as a seal part for a product that is easily damaged by corrosion, such as an electronic part, and is capable of forming a tight seal under low surface pressure with a material having low rigidity and inadequate reliability such as to have a blowhole, and that can prevent reduction in bolt axial load without producing plastic flow (setting) under pressure. The purpose is achieved by a gasket material in which a foamed rubber layer having a closed cell structure is formed, via an adhesive layer, on at least one side of a metal plate, wherein the foamed rubber layer comprises a carboxyl group-modified nitrile rubber, the expansion ratio of the foamed rubber layer is 2.0 to 3.0, and the foamed rubber layer is crosslinked with an epoxy compound.