Pressure-Sensitive Adhesive Sheet for Magnetic Disk Drive Sealing
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Solution Overview
Problem
Pressure-sensitive adhesive sheets used in magnetic disk drives face challenges in maintaining gas barrier properties and close adhesion to adherends when bent along complex shapes, leading to potential gas leakage and separation issues.
Innovation Solution
A pressure-sensitive adhesive sheet with a base comprising a metal layer and resin layers, having an initial elastic modulus and total thickness product of 3000 N/mm or less, ensuring close adhesion and gas barrier properties, even when deformed, with a pressure-sensitive adhesive layer made of acrylic polymer and cross-linking agents for enhanced adhesion and durability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the pressure-sensitive adhesive sheet is made with higher rigidity to maintain gas barrier properties, then gas barrier properties are improved, but the sheet cannot adhere closely to complex-shaped adherends when bent
Solution Approach 1:
The patent applies parameter changes by controlling the initial elastic modulus of the base within a specific range (1000-3000 N/mm²) and limiting the product of initial elastic modulus and total thickness to 3000 N/mm or less. This quantitative parameter optimization allows the sheet to maintain sufficient rigidity for gas barrier properties while achieving the flexibility needed for close adhesion to complex-shaped adherends when bent.
2Ease of operation
If the pressure-sensitive adhesive sheet is made thinner to improve flexibility and adhesion, then ease of operation is improved, but gas barrier properties deteriorate
Solution Approach 1:
The patent resolves this contradiction through parameter optimization by establishing that the product of the initial elastic modulus and total thickness must be 3000 N/mm or less. This allows thinner sheets with better flexibility to maintain adequate gas barrier properties, while the lower bound of initial elastic modulus (1000 N/mm²) ensures sufficient structural integrity.
Solution Approach 2:
The patent employs composite materials by constructing the base from multiple layers including a resin layer and a metal layer. This composite structure provides enhanced gas barrier properties while maintaining flexibility, as the metal layer offers superior gas impermeability and the resin layer provides flexibility and adhesion capability.
3Strength
If the base is made more rigid to prevent separation when bent, then strength is improved, but the sheet cannot maintain close adhesion to adherends
Solution Approach 1:
The patent applies parameter changes by precisely controlling the initial elastic modulus of the base within 1000-3000 N/mm² and the product of initial elastic modulus and total thickness at 3000 N/mm or less. This optimization ensures the base has sufficient strength to resist separation while maintaining the flexibility required for close adhesion to adherends when bent along complex shapes.
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 excellent gas barrier properties and repulsion resistance, maintaining close adhesion to adherends even when bent, effectively preventing gas leakage and ensuring reliable sealing in magnetic disk drives.
Implementation Method 1
a pressure-sensitive adhesive layer having an adhesive surface on a rear side, the adhesive surface being attached to an adherend
Implementation Method 2
A product of an initial elastic modulus of the base and a total thickness of the base is 3000 N/mm or less... excellent gas barrier properties
Data Source
AI summary
A pressure-sensitive adhesive sheet includes a pressure-sensitive adhesive layer and a base including a metal layer and a resin layer, and a product of an initial elastic modulus of the base and a total thickness of the base is 3000 N/mm or less, and a separation distance is 2 mm or less, the separation distance is measured with a peel test with a constant load as follows: a test piece of the pressure-sensitive adhesive sheet having a 10 mm width and a 100 mm length is attached to a surface of a stainless steel test plate and then, the test plate is left standing at a temperature of 23° C. for twenty four hours and then, a load of 100 gf is applied to one end of a length dimension of the test piece vertical to the surface of the test plate and a separation distance of the test piece is measured after one hour.