Switchable Adhesive Composition for Painless Medical Dressing Removal
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Solution Overview
Problem
Conventional switchable adhesives used in medical applications, such as dressings and bandages, often cause trauma and pain upon removal due to high peel strength, and existing solutions require hazardous materials or complex synthesis processes, including multiple solvents, which are environmentally detrimental and time-consuming.
Innovation Solution
A switchable pressure-sensitive adhesive composition comprising a mixture of curable molecules, a photoinitiator, and an internal cross-linker, which undergoes transformation from a tacky to a non-tacky state upon exposure to visible light without requiring UV radiation, allowing for controlled reduction in peel strength and simplified production without multiple solvents.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If conventional pressure sensitive adhesives are used in medical dressings, then strong adhesion to skin is achieved, but skin trauma and pain occur upon removal
Solution Approach 1:
The adhesive transitions from a static high-tack state to a dynamic low-tack state through light irradiation. The adhesive layer contains photoinitiators and curable molecules that, when exposed to visible or UV light, initiate crosslinking reactions that dynamically reduce the adhesive's peel strength, allowing painless removal while maintaining strong initial adhesion
Solution Approach 2:
The adhesive's chemical structure is changed by irradiation-induced crosslinking. The photoinitiators absorb light energy and trigger polymerization of curable molecules (acrylates, methacrylates, vinyl ethers), fundamentally changing the adhesive's molecular architecture from linear chains to crosslinked networks, thereby reducing tack and peel strength
2Reliability
If UV switchable adhesives with photoinitiators are used, then adhesive switching is achieved, but hazardous materials and high UV radiation doses are required
Solution Approach 1:
The invention changes the operational parameters of adhesive switching by using visible light (400-700 nm) instead of high-dose UV radiation. The photoinitiators are selected to absorb in the visible or low-energy UV range, enabling safer activation. The curable molecules are chosen from biocompatible compounds (acrylates, methacrylates, vinyl ethers) that eliminate the need for hazardous photoinitiators
Solution Approach 2:
The invention uses readily available, biocompatible curable molecules (acrylates, methacrylates, vinyl ethers) that can be incorporated into the adhesive without requiring complex or hazardous photoinitiator systems. These materials are safer for medical applications and can be activated by low-dose visible or UV light
3Reliability
If bound-in curable groups are used in adhesive polymers, then switchable adhesive is achieved, but complex synthesis and multiple solvents are required
Solution Approach 1:
The invention separates the adhesive polymer from the curable molecules. Instead of having curable groups bound into the polymer backbone, the adhesive contains free curable molecules (acrylates, methacrylates, vinyl ethers) that can independently undergo polymerization when irradiated. This segmentation simplifies manufacturing by eliminating the need for complex chemical synthesis and multiple solvent removal steps
Solution Approach 2:
The curable functional groups are extracted from the polymer structure and replaced with separate, small-molecule curable compounds (acrylates, methacrylates, vinyl ethers). These extracted curable molecules are mixed into the adhesive formulation and can be activated independently by light irradiation, greatly simplifying the manufacturing process while maintaining switchable adhesive functionality
4Duration of action of stationary object
If conventional adhesives are used for repeated dressing application, then continuous adhesion is maintained, but cumulative skin trauma increases
Solution Approach 1:
The adhesive enables periodic switching between high-tack and low-tack states. During normal wear, the adhesive maintains strong adhesion. When removal is needed, light irradiation periodically switches the adhesive to a low-tack state, allowing painless removal. This periodic switching capability enables repeated dressing applications without cumulative skin trauma
Solution Approach 2:
The adhesive's tack properties are dynamically controllable through light irradiation. The same adhesive layer that provides strong adhesion during wear can be instantly switched to a low-tack state for removal. This dynamic property allows the adhesive to adapt its function based on whether the dressing is being worn or removed, eliminating cumulative trauma while maintaining prolonged wear time
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 achieves a significant reduction in peel strength, reducing skin trauma during removal and simplifying production, while being environmentally friendly and cost-effective, with faster switching times and improved cohesive strength compared to traditional methods.
Implementation Method 1
a switchable pressure-sensitive adhesive composition comprising a mixture of curable molecules, a photoinitiator, and an internal cross-linker, which undergoes transformation from a tacky to a non-tacky state upon exposure to visible light
Data Source
AI summary
The present invention provides switchable adhesives comprising a mixture, in proportions by weight, of 20% to 98% of an adhesive, 2% to 80% of curable molecules and 0.05% to 10% of photoinitiator in which the weight proportion of the adhesive is calculated on the basis of its dry weight and wherein the adhesive includes an internal cross-linker for cross-linking the adhesive during drying to provide a cohesive strength of between 5 and 100 N/12.7×12.7 mm measured according to FINAT test method No. 18. Preferably, the adhesive and curable molecules are mutually soluble when dry, or the curable molecules and adhesive may be uniformly dispersed in each other. Preferably the amount of adhesive in the mixture is in the range 40% to 98% by weight, more preferably 60% to 95% by weight, even more preferably 70% to 85% by weight. Preferably the proportion of curable molecules in the mixture ranges from 2% to 60% by weight, more preferably 5% to 40% by weight, even more preferably 15% to 30% by weight. Preferably, the photoinitiator is present in the mixture in the proportions 0.5% to 5% by weight, more preferably 1% to 3% by weight. Such switchable adhesives are useful in medical dressings and other removable sheet products, and may be simply prepared by stirring the adhesive, the curable molecules and the photoinitiator together at room temperature.