Curable Skin Adhesive Composition With Controlled Crosslink Density
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Solution Overview
Problem
Energy-curable pressure sensitive adhesives (EC-PSAs) have not been adopted for skin-contact applications due to skin sensitization issues, as they contain residual uncured resin components that can migrate and cause harm, and increasing crosslink density to achieve non-sensitization compromises adhesive properties.
Innovation Solution
Formulations of acrylate-functionalized compounds with controlled crosslink density and low migration properties, cured using energy sources like UV or LED, to create non-sensitizing pressure sensitive adhesives that pass cytotoxicity tests.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If crosslink density is increased to reduce residual uncured resin and achieve non-sensitization, then skin safety is improved, but adhesive properties deteriorate
Solution Approach 1:
The patent applies parameter changes by precisely controlling the crosslink density within a specific range (0.1-5 mol/L) and adjusting the ratio of monofunctional to multifunctional acrylate compounds. This optimization allows achieving non-sensitization (passing ISO 10993-5 cytotoxicity tests) while maintaining effective adhesive properties including tack, peel adhesion, and shear resistance
Solution Approach 2:
The patent uses composite material formulation by combining monofunctional acrylate compounds (providing adhesive properties and flexibility) with multifunctional acrylate compounds (providing crosslinking and chemical resistance). This composite approach creates a balanced network structure that simultaneously achieves skin safety and adhesive performance
2Strength
If conventional EC-PSA formulations are used, then adhesive properties are maintained, but skin sensitization occurs due to residual uncured resin migration
Solution Approach 1:
The patent changes the formulation parameters by using exclusively acrylate-functionalized compounds (avoiding methacrylates and other sensitizing monomers) and controlling the crosslink density parameter within 0.1-5 mol/L. This parameter optimization reduces residual uncured resin migration while maintaining adhesive properties
Solution Approach 2:
The patent converts the potential harm of residual uncured resin by using low-migration acrylate compounds with controlled crosslinking. The residual resin that would normally cause sensitization is transformed into a safe state by selecting biocompatible acrylate compounds and optimizing conversion through controlled crosslink density
3Reliability
If high crosslink density is achieved to minimize residual resin, then non-sensitization is obtained, but adhesive performance is compromised
Solution Approach 1:
The patent applies parameter changes by defining an optimal crosslink density range (0.1-5 mol/L) rather than maximizing it. This controlled parameter approach ensures sufficient crosslinking for non-sensitization while preserving the adhesive network's flexibility and bonding capability
Solution Approach 2:
The patent uses partial action by incorporating only 5-50 wt% multifunctional acrylate compounds (the rest being monofunctional). This partial crosslinking approach is sufficient to achieve non-sensitization without over-crosslinking that would compromise adhesive performance
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 formulations provide adhesives with effective adhesive properties while minimizing skin sensitization, ensuring safety and compliance with ISO 10993-5 cytotoxicity standards.
Implementation Method 1
Energy curing (EC) refers to the conversion of a curable composition (which may be referred to as a 'resin') to polymer using an energy source such as an electron beam (EB), ultraviolet (UV) lamp, or light-emitting diode (LED)
Data Source
AI summary
Non-sensitizing pressure sensitive adhesives which are useful in medical applications and other uses where an adhesive is in contact with skin are obtained by energy-curing compositions containing one or more acrylate-functionalized compounds and possibly other components which are selected such that the cured adhesive passes an in vitro cytotoxicity test in accordance with ISO 10993-5 (2009).