Molding Compact for Transdermal Sheet Leakage Prevention

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Solution Overview

Problem

The manufacturing methods for transdermal absorption sheets with needle-shaped protruding parts face challenges in preventing the leakage of the drug-containing solution filled into the needle-shaped recessed parts during the molding process.

Innovation Solution

A molding compact is configured by laminating a first member with needle-shaped recessed parts, a second member made of a waterproof and moisture-permeable material, and a third member of a rigid body, with specific through holes and air permeability characteristics to prevent solution leakage and ensure easy filling and adhesion, along with a manufacturing method involving vacuum suction to remove air and secure the solution.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If a through hole is provided at the bottom of the needle-shaped recessed part to allow air to escape, then air can easily come out during filling, but the drug-containing solution may leak from the through hole

Engineering Contradiction:
Improvefilling easeVSAvoidleakage prevention
Core Design Contradiction:
Ease of manufactureVSReliability

Solution Approach 1:

The mold is divided into multiple members (first member with recessed parts, second member with through holes, third member as base) that work together. The through holes are segmented and distributed in the second member rather than being directly in the recessed parts, allowing air escape while preventing solution leakage through proper segmentation of functions.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Different parts of the mold have different properties: the first member has needle-shaped recessed parts for forming needles, the second member has through holes for air escape but is positioned to prevent solution leakage, and the third member provides structural support. Each member has localized quality suited to its specific function.

Inventive Principle:
Principle #3Local quality

2Manufacturing precision

If the needle-shaped recessed part has very minute dimensions to form thin needles, then high aspect ratio and sharp pointed ends can be achieved, but the solution is not easily filled into the recessed part due to air and surface tension

Engineering Contradiction:
Improveneedle shape precisionVSAvoidfilling ease
Core Design Contradiction:
Manufacturing precisionVSEase of manufacture

Solution Approach 1:

The air entrapment problem is extracted and solved separately by providing through holes in the second member that allow air to escape during filling. This separates the air removal function from the needle formation function, enabling precise needle shaping while facilitating easy filling.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The second member with through holes acts as an intermediary between the first member (recessed parts) and the filling process. It mediates the filling operation by providing air escape paths without directly interfering with the precise formation of minute needle-shaped recessed parts.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Ease of operation

If a thin needle with high aspect ratio is used for painless skin penetration, then sharp pointed ends are achieved, but the needle material is difficult to secure in the recessed part against drying stress and shearing force

Engineering Contradiction:
Improveskin penetration comfortVSAvoidneedle securing strength
Core Design Contradiction:
Ease of operationVSStrength

Solution Approach 1:

The mold members have asymmetric positioning and properties: the through holes are positioned in the second member rather than symmetrically in the recessed parts, and the members have different material properties (waterproof and moisture-permeable). This asymmetric design allows air escape while maintaining needle securing strength through the lamination structure.

Inventive Principle:
Principle #4Asymmetry

Solution Approach 2:

The mold uses composite construction with multiple members having different properties: the first member with recessed parts, the second member with through holes that is waterproof and moisture-permeable, and the third member as rigid base. This composite structure provides both air escape capability and sufficient strength to secure thin needle material during drying and handling.

Inventive Principle:
Principle #40Composite materials

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 solution effectively prevents leakage of the drug-containing solution, ensuring a defect-free transdermal absorption sheet with improved productivity and biocompatibility for painless skin penetration.

Implementation Method 1

a second member provided on a back surface of the first member, the second member being composed of a waterproof and moisture-permeable material

Methodology Applied
Scientific EffectPermeation: Permeation

Implementation Method 2

a manufacturing method involving vacuum suction to remove air and secure the solution

Methodology Applied
Scientific EffectVacuum: Vacuum

Data Source

PatentEP2921201B1Molding compact, and manufacturing method for transdermal absorption sheet
Publication Date: 2019.12.25 FUJIFILM CORP
  • EP2921201B1 patent drawingFigure 1A~1B
  • EP2921201B1 patent drawingFigure 2A~2B
  • EP2921201B1 patent drawingFigure 3(A)~3(G)

AI summary

A molding compact for forming a transdermal absorption sheet on which a needle-shaped protruding part is arranged is a molding compact that is a laminate of: a first member having a needle-shaped recessed part formed on a front surface thereof, the needle-shaped recessed part being an inverse of the needle-shaped protruding part; a second member provided on a back surface of the first member, the second member being composed of a waterproof and moisture-permeable material; and a third member provided on a back surface of the second member, the third member being composed of a rigid body. Provided are a molding compact that makes it possible to prevent leakage of a drug-containing solution filled into the needle-shaped recessed part, and a manufacturing method for a transdermal absorption sheet using the molding compact.