Low Stretchable Skin Patch with Rounded Corners
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Solution Overview
Problem
Conventional skin patches with high stretchability tend to detach undesirably from the skin, especially when worn under clothes, due to friction, and lack effective means for controlled detachment and adhesion.
Innovation Solution
A low stretchable skin patch design with a polygonal outer shape and rounded corners, where the ratio of curved sections to straight-line sections is limited to 1.22 or less, and a laminate support of non-porous polyethylene terephthalate film and porous polyethylene terephthalate non-woven fabric, ensuring the adhesive layer is on the porous side, providing a balance of adhesion and ease of detachment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the patch has high stretchability, then it can adapt to skin movement, but it detaches undesirably from the skin due to friction with clothes
Solution Approach 1:
The patent changes the physical parameter of stretchability from high to low, creating a patch that maintains stable adhesion to the skin while being covered by clothes. The low stretchability prevents excessive movement and friction that would cause detachment, resolving the contradiction between adaptability and adhesion stability.
2Reliability
If the patch has low stretchability, then it maintains stable adhesion, but it becomes difficult to detach when needed
Solution Approach 1:
The patent introduces dynamic characteristics to the patch system, where the adhesive layer can transition between strong adhesion during wear and easy detachment when needed. This dynamic property allows the patch to maintain stable adhesion during use while enabling controlled removal when required.
3Duration of action of stationary object
If the patch is adhered for a long time, then it provides sustained drug delivery, but it detaches due to friction with clothes
Solution Approach 1:
The patent changes the stretchability parameter to low, which prevents the patch from detaching due to friction with clothes during long-term wear. This parameter change enables sustained adhesion over extended periods, ensuring continuous drug delivery while maintaining adhesion stability.
4Strength
If the patch has round corners, then it reduces stress concentration, but it still detaches when adhered under clothes for a long time
Solution Approach 1:
The patent changes the stretchability parameter from high to low, which is the critical factor preventing detachment under clothes. While round corners provide stress distribution benefits, the low stretchability is the decisive parameter that maintains adhesion stability during long-term wear under clothing.
Data Source
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AI summary
The present invention provides to a patch and a patch preparation having low stretchability, which can be continuously adhered to the skin for a long time without undesirable detachment and marked falling off from the skin due to various factors during adhesion, and specifically provides a low stretchable patch and a patch preparation containing a support and an adhesive layer formed on one surface of the support, wherein a ratio P of the total length W (mm) of curved sections of a planar outer shape of the patch to the total length S (mm) of straight-line sections of the planar outer shape of the patch (W/S) is not more than 1.22, and, when the curved sections are approximated by a circular arc, the radius R (mm) of the circular arc is not less than 0.5 mm.