Pressure Sensitive Adhesive Sheet With Segmented Concave Portions
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Solution Overview
Problem
Pressure sensitive adhesive sheets with grooves for air escape face challenges in venting air effectively due to groove width limitations, leading to surface dents, reduced adhesive strength, and issues with adhesive deposits and cutting patterns, while existing solutions struggle with blister resistance and compatibility with low-polarity substrates.
Innovation Solution
A pressure sensitive adhesive sheet with a resin layer containing silica particles and concave portions of varying shapes and sizes, forming a multi-layer structure for enhanced air escape and adhesion, which improves blister resistance and pressure sensitive adhesion characteristics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If grooves with small width are formed on the pressure sensitive adhesive layer, then the adhesive strength is maintained, but air venting efficiency deteriorates
Solution Approach 1:
The invention divides the air venting function into multiple discrete grooves distributed across the adhesive layer surface. Each groove acts as an independent air escape channel, collectively providing efficient air venting while maintaining small individual groove widths that preserve adhesive strength.
Solution Approach 2:
The grooves are strategically positioned and sized to create local air escape pathways without compromising the overall adhesive layer integrity. The groove dimensions and distribution are optimized to provide sufficient air venting capacity while maintaining adhesive strength in the surrounding areas.
2Productivity
If grooves with large width are formed on the pressure sensitive adhesive layer, then air venting efficiency is improved, but adhesive strength and surface appearance deteriorate
Solution Approach 1:
Instead of forming few large grooves that would compromise adhesive strength, the invention segments the air venting function into numerous smaller grooves. This segmentation allows the cumulative air venting capacity to match that of large grooves while preserving adhesive integrity and surface appearance.
3Productivity
If grooves are disposed in a prescribed pattern, then air escape is facilitated, but adhesive strength is reduced locally at groove positions
Solution Approach 1:
The grooves are designed with specific dimensional characteristics and distribution patterns that create localized air escape pathways. The local groove structures are optimized to provide air venting function while minimizing the impact on adhesive strength in the immediate vicinity of each groove.
Solution Approach 2:
The prescribed pattern distributes grooves across the surface to segment the air venting function, ensuring that no single location bears the full burden of air escape. This distribution mitigates local adhesive strength reduction by spreading the structural impact across multiple small features rather than concentrating it in fewer large features.
4Ease of operation
If the pressure sensitive adhesive sheet is peeled obliquely from the adherend, then release is achieved, but adhesive deposits remain on the adherend due to varying adhesion characteristics
Solution Approach 1:
The grooves create localized variations in adhesive layer thickness and air escape characteristics that influence peeling behavior. These local structural differences help equalize the peeling force distribution across the surface, reducing the formation of adhesive deposits during oblique peeling operations.
Data Source
Figure 1(a)~1(d)
Figure 2(a)~2(b)
Figure 3(a)~3(b)
AI summary
Provided is a pressure sensitive adhesive sheet containing, on a substrate or a release material, a resin layer that includes a resin part (X) containing a resin as a main component, and a particle part (Y) consisting of fine particles, at least a surface (α) of the resin layer being opposite to the side thereof on which the substrate or the release material is provided having pressure sensitive adhesiveness, wherein plural concave portions having a maximum height difference of 0.5 µm or more exist in a predetermined region (P) on the surface (α), and 95% or more of the plural concave portions existing inside the region (P) have shapes differing from each other, and one or more such concave portions exist in a predetermined region (Q) on the surface (α). When attached to an adherend, the pressure sensitive adhesive sheet can readily remove air accumulation to be formed and therefore exhibits excellent air escape property, and has good blister resistance and pressure sensitive adhesion characteristics.