Wearable Adhesive Composition With Tin-Free Catalyst Balance
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Solution Overview
Problem
Existing urethane-based adhesive agents for wearable devices face issues with imbalance between adhesive force to the skin and the device, potential health risks from tin-based catalysts, and gelation during reaction, leading to skin irritation and residue formation.
Innovation Solution
A polyurethane-based adhesive composition using a hydroxyl-terminated urethane prepolymer and a polyisocyanate compound, synthesized with a tin-free catalyst, specifically an organometallic catalyst like zinc or bismuth, to achieve a balanced adhesive force and skin friendliness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a relatively large amount of zinc-based catalyst is used to promote urethane reaction, then the adhesive force to skin is improved, but gelation occurs and adhesive force to device deteriorates
Solution Approach 1:
The patent changes the catalyst type from zinc-based to tin-free organometallic catalyst (such as bismuth-based catalyst), and optimizes the catalyst amount to 0.001-0.050 parts by mass per 100 parts by mass of oxyalkylene polymer. This parameter change prevents gelation while maintaining adequate adhesive force to skin and improved adhesive force to device.
2Strength
If tin-based catalyst is used to synthesize adhesive composition, then the adhesive properties are improved, but health safety deteriorates
Solution Approach 1:
The patent extracts and removes the harmful tin-based catalyst from the adhesive composition synthesis process. Instead, it uses tin-free organometallic catalysts such as bismuth-based catalysts or zinc-based catalysts at optimized low concentrations, thereby eliminating health risks associated with tin compounds while maintaining adequate adhesive properties.
3Strength
If the adhesive force to device is increased, then the bonding strength is improved, but the load on skin deteriorates
Solution Approach 1:
The patent optimizes multiple parameters including catalyst type (tin-free organometallic), catalyst amount (0.001-0.050 parts by mass per 100 parts by mass of oxyalkylene polymer), and oxyalkylene polymer structure (average content of ethylene oxide structural units 60% by mass or less). These parameter changes achieve a balanced adhesive composition that provides sufficient adhesive force to both skin and device without excessive load on skin.
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 adhesive composition provides a good balance between skin adhesion and device adhesion, is skin-friendly, and reduces the risk of gelation and residue formation, while maintaining effective adhesive properties.
Implementation Method 1
the hydroxyl-terminated urethane prepolymer is a reaction product of an oxyalkylene polymer and a diisocyanate compound in the presence of a tin-free catalyst
Implementation Method 2
an adhesive agent, being a cured product of the adhesive composition
Data Source
AI summary
Provided are an adhesive composition that can provide an adhesive agent having a good balance between the adhesive force to the skin and the adhesive force to a device and being skin friendly, a method for producing the same, as well as an adhesive agent, a patch, a wearable device, and a wearable device kit. The adhesive composition of the present invention comprises a hydroxyl-terminated urethane prepolymer and a polyisocyanate compound, the hydroxyl-terminated urethane prepolymer is a reaction product of an oxyalkylene polymer and a diisocyanate compound in the presence of a tin-free catalyst, and the tin-free catalyst is more than 0.001 parts by mass and less than 0.050 parts by mass per 100 parts by mass of the oxyalkylene polymer.