Foamed Adhesive Strip Shock Resistance
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Solution Overview
Problem
Conventional pressure-sensitive adhesive strips used in the consumer electronics industry face challenges in providing adequate shock resistance, particularly in the z-plane, and often fail under mechanical stress and temperature variations, leading to deformation and loss of holding power.
Innovation Solution
A pressure-sensitive adhesive strip comprising a non-stretchable film carrier with self-adhesive layers made of vinyl aromatic block copolymers foamed with microballoons, where the average diameter of the cavities formed by the microballoons is between 20 to 40 μm, providing enhanced shock resistance in both the x, y, and z planes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If a film carrier is integrated into the adhesive strip to suppress deformation, then the stability of the adhesive strip is improved, but the bond strength between the adhesive and component deteriorates due to cohesive fracture under shock load
Solution Approach 1:
The adhesive strip uses a composite structure with a foamed core layer made of syntactic foam (hollow spheres embedded in polymer matrix) combined with self-adhesive layers. This composite material provides both the stability needed to suppress deformation and the shock resistance to maintain bond strength, as the hollow spheres absorb impact energy while the polymer matrix maintains structural integrity.
Solution Approach 2:
The adhesive strip has different layers with different properties: the foamed core layer provides shock absorption and stability, while the self-adhesive layers provide bonding capability. This local differentiation of material properties allows the strip to simultaneously achieve deformation suppression and maintain strong adhesion under shock loads.
2Reliability
If the adhesive strip is made robust to resist shock loads, then the shock resistance is improved, but the adhesive strip itself fails under extreme shock through cohesive fracture
Solution Approach 1:
The foamed core layer with hollow spheres acts as a cushioning element that absorbs shock energy before it can cause cohesive fracture. The compressible foam structure provides preliminary protection against extreme loads, allowing the adhesive strip to withstand shock events without bond failure.
3Adaptability or versatility
If die-cutting is used to achieve complex geometries for miniature components, then the adaptability to component shapes is improved, but the adhesive tape becomes delicate and prone to deformation
Solution Approach 1:
The composite structure with foamed core and self-adhesive layers creates a tape that is both adaptable to complex geometries through die-cutting and stable enough to resist deformation. The foam core provides structural support while allowing the die-cut shape to conform to miniature components.
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 achieves high impact strength and push-out resistance in the z-direction, along with improved ball drop test results, making it suitable for bonding components like batteries and electronic devices, such as cell phones, with enhanced durability and reliability.
Implementation Method 1
a layer SK1 of a self-adhesive mass arranged on one of the surfaces of the film carrier layer F and based on a microballoon-foamed vinyl aromatic block copolymer mass... providing enhanced shock resistance in both the x, y, and z planes
Implementation Method 2
the film carrier layer F has an elongation at break of less than 300% in both the longitudinal and transverse directions... high impact strength and push-out resistance in the z-direction
Data Source
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AI summary
The invention relates to an adhesive strip comprising: • an inner layer F of a non-stretchable film carrier, • a layer SK1 of a self-adhesive mass arranged on one of the surfaces of the film carrier layer F and based on a vinyl aromatic block copolymer mass foamed with microballoons, • a layer SK2 of a self-adhesive mass arranged on the surface of the film carrier layer F opposite layer SK1 and based on a vinyl aromatic block copolymer mass foamed with microballoons, wherein the mean diameter of the cavities formed by the microballoons in the self-adhesive mass layers SK1 and SK2 is independently 20 to 60 µm.