Adhesive Skin Patch with Ultra-Thin Base Film and Acrylic Copolymer

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Solution Overview

Problem

Adhesive skin patches face challenges in achieving good adhesiveness and fit feeling on irregular skin surfaces, with issues of irritation, moisture permeability, and flexibility due to the complex nature of human skin.

Innovation Solution

The adhesive skin patch is designed with a base film thickness of 1 to 9 µm and a pressure-sensitive adhesive layer thickness of 16 to 50 µm, using an acrylic copolymer containing (meth)acrylic acid alkyl ester and alkoxy group-containing ethylenically unsaturated monomers, which provides balanced adhesiveness, moisture permeability, and flexibility.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If the adhesive skin patch is made thicker to improve fit feeling and flexibility, then comfort is improved, but the patch becomes more noticeable and less like it is not adhered

Engineering Contradiction:
Improvefit feelingVSAvoidbase film thickness
Core Design Contradiction:
Ease of operationVSLength of stationary object

Solution Approach 1:

The patent applies this principle by using an ultra-thin base film (1-9 μm) that is flexible enough to conform to skin contours while remaining imperceptible. The thin film achieves flexibility through careful material selection and thickness control, allowing it to move with the skin without being noticeable, thus resolving the contradiction between thickness and fit feeling.

Inventive Principle:
Principle #30Flexible shells and thin films

Solution Approach 2:

The patent changes the thickness parameter of the base film to an optimized range (1-9 μm) that balances flexibility and imperceptibility. By precisely controlling this parameter, the patch achieves good fit feeling while remaining thin and unnoticeable on the skin surface.

Inventive Principle:
Principle #35Parameter changes

2Ease of operation

If the pressure-sensitive adhesive layer is made thinner to improve flexibility and reduce noticeability, then fit feeling is improved, but adhesiveness to the skin surface deteriorates

Engineering Contradiction:
Improvefit feelingVSAvoidadhesiveness
Core Design Contradiction:
Ease of operationVSStrength

Solution Approach 1:

The patent optimizes the adhesive layer thickness to a specific range (16-50 μm) that maintains both flexibility and adhesiveness. This parameter optimization ensures the layer is thin enough for comfort yet thick enough to provide reliable adhesion to the skin surface.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent uses an acrylic copolymer composed of multiple monomer components ((meth)acrylic acid alkyl ester and alkoxy group-containing ethylenically unsaturated monomer) to create a composite adhesive material that achieves both flexibility and strong adhesion within a thin layer, resolving the contradiction between thickness and adhesiveness.

Inventive Principle:
Principle #40Composite materials

3Ease of operation

If the base film is made thinner to improve flexibility and comfort, then fit feeling is improved, but the patch becomes more susceptible to breaking during use

Engineering Contradiction:
ImproveflexibilityVSAvoidbreak resistance
Core Design Contradiction:
Ease of operationVSStrength

Solution Approach 1:

The patent identifies and applies an optimal thickness range (1-9 μm) for the base film that balances flexibility and break resistance. Within this range, the film maintains sufficient mechanical strength for practical use while remaining thin and flexible for comfort.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent employs advanced thin film technology to achieve a base film that is both ultra-thin and sufficiently durable. Through careful material selection and thickness control, the film achieves the necessary combination of flexibility and break resistance for practical application.

Inventive Principle:
Principle #30Flexible shells and thin films

4Strength

If the adhesive skin patch uses a conventional thickness to ensure durability, then break resistance is improved, but moisture permeability and skin irritation issues worsen

Engineering Contradiction:
Improvebreak resistanceVSAvoidmoisture permeability and irritation
Core Design Contradiction:
StrengthVSObject-affected harmful factors

Solution Approach 1:

The patent reduces the base film thickness to an optimized range (1-9 μm) that dramatically improves moisture permeability while maintaining sufficient break resistance through careful material selection. This parameter change resolves the contradiction between durability and moisture management.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent uses ultra-thin film technology to create a base film that is permeable enough to prevent moisture accumulation and irritation while remaining durable enough for practical use. The thin film structure allows moisture vapor transmission while maintaining mechanical integrity.

Inventive Principle:
Principle #30Flexible shells and thin films

Data Source

PatentEP3498245B1Adhesive skin patch and wound body of adhesive skin patch
Publication Date: 2023.06.07 NITTO DENKO CORP

AI summary

The invention relates to an adhesive skin patch including a base film, a pressure-sensitive adhesive layer provided on one side of the base film, and a release liner peelably laminated so as to cover an adhesive surface of the pressure-sensitive adhesive layer, wherein the pressure-sensitive adhesive layer contains an acrylic copolymer, and wherein the base film has a thickness of 1 to 9 µm, and the pressure-sensitive adhesive layer has a thickness of 16 to 50 µm. The adhesive skin patch of the invention has good adhesiveness to a skin surface and good fit feeling as if the adhesive skin patch is not adhered. The invention also relates to a wound body of an adhesive skin patch obtained by winding the adhesive skin patch