Thermally Removable Adhesive Sheet Using Plant-Derived Polyester
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Solution Overview
Problem
Conventional thermally removable pressure-sensitive adhesive sheets rely on fossil resources and contribute to environmental issues like fossil depletion and carbon dioxide emissions, lacking plant-derived alternatives with stable adherability and good peelability after heating.
Innovation Solution
A thermally removable pressure-sensitive adhesive sheet composed of a polyester-based adhesive layer containing lactic acid, dibasic acid, glycol, and a foaming agent, with a crosslinking agent, specifically designed to have a weight average molecular weight of 20,000 to 200,000 and a glass transition temperature of -70 to -20°C, using thermally expandable microspheres for foaming, and a biodegradable substrate for environmental sustainability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If plant-derived polyester is used as adhesive material, then environmental friendliness is improved, but adherability stability may deteriorate
Solution Approach 1:
The patent controls the glass transition temperature of the polyester adhesive within -70 to -20°C and weight average molecular weight within 20,000 to 200,000 to optimize both environmental friendliness and adherability stability. By adjusting these parameters, the adhesive maintains reliable performance while using plant-derived materials.
Solution Approach 2:
The patent creates a composite pressure-sensitive adhesive layer combining plant-derived polyester with thermally expandable microspheres (5-60 parts by weight per 100 parts polyester). This composite structure achieves both environmental sustainability and stable adhesive properties through the synergistic effect of the polyester matrix and microsphere reinforcement.
2Ease of operation
If thermally expandable microspheres are added to improve peelability, then adhesive strength after heating is improved, but initial adherability may deteriorate
Solution Approach 1:
The patent optimizes the content of thermally expandable microspheres to 5-60 parts by weight per 100 parts polyester, and controls the gel fraction at 40-85% after heating. These parameter controls ensure that sufficient microspheres are present to provide easy peelability after heating, while maintaining enough adhesive matrix to guarantee stable initial adherability.
3Strength
If polyester molecular weight is increased to improve adherability, then adhesive strength is improved, but processability may deteriorate
Solution Approach 1:
The patent specifies the weight average molecular weight of the polyester within 20,000 to 200,000. This molecular weight range provides sufficient chain entanglement and intermolecular forces to ensure strong adhesive bonding, while remaining low enough to allow proper flow and distribution during the coating and foaming processes.
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 a globally environmentally-friendly adhesive sheet with stable adherability before foaming and easy peelability after heating, reducing fossil resource depletion and achieving carbon neutrality, while maintaining effective adhesive properties.
Implementation Method 1
the pressure-sensitive adhesive layer, which contains an expanding or foaming agent such as thermally expandable microspheres, expands or foams when heated
Data Source
AI summary
Provided is a thermally removable pressure-sensitive adhesive sheet that is produced using a plant-derived raw material, is global environmentally-friendly, has stable adherability before foaming by heating, and has good peelability after foaming by heating. The thermally removable pressure-sensitive adhesive sheet includes a substrate and a pressure-sensitive adhesive layer that is provided on at least one side of the substrate and made from a polyester-based pressure-sensitive adhesive composition containing a polyester including at least a lactic acid unit, a dibasic acid unit, and a glycol unit, a foaming agent, and a crosslinking agent, wherein the dibasic acid unit includes a dimer acid, the polyester has a weight average molecular weight of 20,000 to 200,000 and a glass transition temperature of -70 to -20°C as measured using a differential scanning calorimeter at a temperature rise rate of 20°C/minute, and the polyester has a hydroxyl value of 1 to 60 mgKOH/g.