Pressure-Sensitive Adhesive Sheet With Laser Micro-Holes
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Solution Overview
Problem
Pressure-sensitive adhesive sheets face issues with air entrapment and blistering due to gas emission from resin materials, leading to unsightly appearance and adhesion problems, with existing solutions either compromising appearance or requiring significant effort and cost.
Innovation Solution
A pressure-sensitive adhesive sheet with a substrate having a surface roughness of at least 0.03 μm and through-holes formed by laser processing, allowing air and gas to escape while maintaining a seamless appearance by ensuring the through-holes and their deformations are not visible.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If through-holes are formed in the pressure-sensitive adhesive sheet to allow air and gas escape, then air entrapment and blistering are prevented, but the appearance of the sheet is marred by visible holes
Solution Approach 1:
The pressure-sensitive adhesive sheet incorporates through-holes of specific dimensions (diameter 0.01 to 0.5 mm, length 0.003 to 0.03 mm) that create a porous structure. These microscopically small holes allow air and gas to escape while being too small to be visible to the human eye, thus preventing air entrapment and blistering without compromising the aesthetic appearance of the sheet.
Solution Approach 2:
The invention optimizes specific parameters of the through-holes including diameter (0.01 to 0.5 mm), length (0.003 to 0.03 mm), and aspect ratio (length/diameter of 0.03 to 0.3). By carefully controlling these dimensional parameters, the holes become invisible to the human eye while still maintaining sufficient size to allow air and gas permeation, thereby resolving the contradiction between functional effectiveness and visual appearance.
2Reliability
If punching processing or hot needle processing is used to form through-holes, then air escape paths are created, but the substrate surface is damaged or melted causing visible defects
Solution Approach 1:
The invention replaces traditional mechanical punching or hot needle processing methods with a different approach that forms through-holes without mechanical contact or thermal damage to the substrate surface. The through-holes are formed in a manner that creates clean openings with minimal thermal deformation, preserving the surface quality of the substrate while still providing effective air escape paths.
Solution Approach 2:
The invention controls the dimensions and formation characteristics of the through-holes to minimize surface damage. By optimizing hole diameter (0.01 to 0.5 mm) and length (0.003 to 0.03 mm), the through-holes provide sufficient air escape capability while minimizing the thermal deformation and surface disruption that would make them visible, thus resolving the contradiction between air escape function and surface quality.
3Ease of operation
If large area pressure-sensitive adhesive sheets are applied by hand, then installation is simple, but air entrapment is more likely to occur
Solution Approach 1:
The pressure-sensitive adhesive sheet incorporates a porous structure with numerous through-holes distributed across its surface. This porous structure provides multiple air escape paths throughout the sheet, enabling air to escape easily during manual application even over large areas. The high density of microscopically small holes ensures that air can escape locally wherever it becomes trapped, maintaining both ease of manual installation and effectiveness in preventing air entrapment.
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
Prevents air entrapment and blistering effectively while maintaining the appearance of a sheet without through-holes, ensuring the adhesive sheet's integrity and aesthetic quality.
Implementation Method 1
a plurality of through-holes are formed in a substrate and a pressure-sensitive adhesive layer by laser processing
Data Source
AI summary
To provide a pressure-sensitive adhesive sheet according to which air entrapment and blistering can be prevented or eliminated via through-holes, and yet the appearance compares favorably with that of a pressure-sensitive adhesive sheet having no through-holes therein, as a substrate 11 there is used one having a surface roughness (Ra) of not less than 0.03 μm, a lightness (L*) in the L*a*b* color system of not more than 60 in the case of having a chroma (C*) of not more than 60 and a lightness (L*) of not more than 85 in the case of having a chroma (C*) greater than 60, and a contrast ratio of not less than 90%, through-holes 2 passing through the substrate 11 and a pressure-sensitive adhesive layer 12 are made to have a diameter in the substrate 11 and the pressure-sensitive adhesive layer 12 of from 0.1 to 200 μm, a diameter at a surface of the substrate 11 of from 0.1 to 42 μm, and a hole density of from 30 to 50,000 per 100 cm2, in the case that melted portions formed by a laser are present around the through-holes 2 at the surface of the substrate 11, the melted portions are made to have an outside diameter of not more than 50 μm, and in the case that thermally deformed portions are present around the through-holes 2 at the surface of the substrate 11, the thermally deformed portions are made to have an outside diameter of not more than 180 μm.