Double-Sided Adhesive Sheet Thinner Substrate and Solvent Control
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Solution Overview
Problem
The production of double-sided pressure-sensitive adhesive sheets faces challenges in reducing plastic waste and achieving thinness while maintaining good adhesive properties and appearance, as conventional methods either require thick substrates to prevent tears and creases or result in defects due to residual organic solvents in the adhesive layers.
Innovation Solution
The use of a water-dispersed pressure-sensitive adhesive composition and extended drying times or higher temperatures in the first drying step to minimize residual toluene and ethyl acetate in the adhesive layers, combined with thinner release liners, allows for the production of a double-sided pressure-sensitive adhesive sheet with reduced plastic waste and improved appearance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of moving object
If the substrate film thickness is reduced to achieve thinness, then the overall sheet thickness is reduced, but the substrate becomes prone to tear, warp, and crease during the scraping process
Solution Approach 1:
The release liner is subjected to release treatment in advance before the scraping process, creating a protective surface that prevents adhesion to the coater metal member. This preliminary preparation allows thinner substrate films to be used without experiencing tear, warp, or crease during the scraping operation, as the release-treated surface acts as a buffer that maintains substrate integrity throughout the coating process
2Reliability
If conventional release liners are used with thick substrates, then the substrate stability is maintained, but plastic waste increases and environmental load increases
Solution Approach 1:
The invention changes the key parameter of release liner thickness from conventional thick specifications to 35 μm or less. By optimizing the thickness parameter to this specific range and combining it with release treatment, the substrate remains stable during scraping while significantly reducing the amount of plastic waste generated, as the thinner liner still provides sufficient protective function without the excess material of conventional liners
3Reliability
If organic solvent-based pressure-sensitive adhesive composition is used, then good adhesive properties are achieved, but residual toluene and ethyl acetate cause defects due to vaporization during heating
Solution Approach 1:
The invention changes the chemical composition parameter by switching from organic solvent-based adhesive to water-dispersed adhesive. This fundamental parameter change eliminates toluene and ethyl acetate from the formulation, thereby removing the source of vaporization defects while preserving adhesive performance. The water-dispersed composition provides equivalent adhesive properties without the harmful solvent vaporization issue that plagues conventional organic-based formulations
4Manufacturing precision
If the first drying step is extended or heated at higher temperatures to minimize residual solvents, then adhesive layer purity is improved, but energy consumption increases
Solution Approach 1:
The invention changes the fundamental composition parameter from organic solvent-based to water-dispersed adhesive, which fundamentally alters the drying requirements. Water-dispersed adhesives require significantly less energy for drying compared to organic solvent-based adhesives, as water evaporates at lower temperatures and requires less energy removal. This parameter change achieves high adhesive layer purity (minimal residual solvents) while dramatically reducing the energy consumption of the drying process
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
This approach enables the production of a double-sided pressure-sensitive adhesive sheet that reduces environmental impact, achieves the desired thinness, and ensures good adhesive properties by minimizing defects caused by solvent vaporization, thus addressing the limitations of conventional methods.
Implementation Method 1
the coating film on the release liner is dried by heating to form a pressure-sensitive adhesive layer
Implementation Method 2
the coating film on the release liner is dried by heating to form a pressure-sensitive adhesive layer
Data Source
AI summary
The double-sided pressure-sensitive adhesive sheet of the present invention includes a substrate film, a first pressure-sensitive adhesive layer, a second pressure-sensitive adhesive layer, and a release liner. The substrate film has a first surface and a second surface opposite the first surface. The first pressure-sensitive adhesive layer is disposed on the first surface, and has a first adhesive surface opposite the substrate film. The second pressure-sensitive adhesive layer is formed from a coating film of the pressure-sensitive adhesive composition applied on the second surface, and has a second adhesive surface opposite the substrate film. The release liner is in releasable contact with the first adhesive surface. The emission amount of toluene and ethyl acetate from the first pressure-sensitive adhesive layer on heating at 80° C. for 30 minutes is 10 μg/g or less.