Medical Vial Rubber Plug Adhesion Prevention

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Solution Overview

Problem

Rubber plugs for medical vial containers face issues with adhesion during handling and conveyance due to their adhesive nature, leading to difficulties in smooth conveyance and packaging, especially when inverted or in large quantities.

Innovation Solution

A rubber plug with a thermoplastic elastomer composition, featuring a discoid cap portion and a cylindrical leg portion, where the cylindrical leg is coated with a synthetic resin film and the discoid cap has a Shore A hardness of 25-55 and surface roughness of 2.5-10.5µm, reducing adhesion and enabling smooth conveyance and packaging.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If rubber plugs are made of adhesive rubber material to ensure sealing performance, then sealing performance is improved, but adhesion between plugs during handling and conveyance occurs

Engineering Contradiction:
Improvesealing performanceVSAvoidadhesion between plugs
Core Design Contradiction:
ReliabilityVSObject-generated harmful factors

Solution Approach 1:

The patent applies different surface treatments to different parts of the rubber plug. The outer peripheral surface of the leg portion is coated with a synthetic resin film to prevent adhesion during handling, while the inner surface maintains its adhesive rubber material properties for effective sealing. This local differentiation resolves the contradiction between sealing performance and adhesion prevention.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

A synthetic resin film is introduced as an intermediary layer between the adhesive rubber material and the handling environment. This film acts as a mediator that prevents direct contact and adhesion between rubber plugs during conveyance and packaging, while allowing the underlying rubber material to maintain its sealing functionality.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Ease of manufacture

If rubber plugs have a smooth surface for easy manufacturing, then manufacturing is simplified, but adhesion to conveying surfaces occurs during inverted conveyance

Engineering Contradiction:
Improvemanufacturing simplicityVSAvoidconveyance smoothness
Core Design Contradiction:
Ease of manufactureVSEase of operation

Solution Approach 1:

The patent creates different surface characteristics in different locations: the top surface of the cap portion is given a rough texture to prevent adhesion to conveying surfaces during inverted conveyance, while the inner surfaces maintain smoothness for proper sealing. This local differentiation resolves the contradiction between manufacturing simplicity and conveyance smoothness.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

Instead of making the entire surface smooth for easy manufacturing, the patent inverts the approach by making the conveyance-facing surface rough to specifically address the adhesion problem during inverted conveyance, while keeping other surfaces smooth for manufacturing and sealing purposes.

Inventive Principle:
Principle #13The other way round (Inversion)

3Object-generated harmful factors

If the entire surface of the rubber plug is coated with synthetic resin film to prevent adhesion, then adhesion prevention is improved, but sealing performance and chemical resistance deteriorate

Engineering Contradiction:
Improveadhesion preventionVSAvoidsealing performance and chemical resistance
Core Design Contradiction:
Object-generated harmful factorsVSReliability

Solution Approach 1:

The patent selectively applies the synthetic resin film coating only to the outer peripheral surface of the leg portion where adhesion prevention is needed during handling, while leaving the inner surfaces that contact the vial opening and sealing areas as untreated adhesive rubber material. This ensures both adhesion prevention and maintained sealing performance.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

Instead of applying the synthetic resin film to the entire surface, the patent applies it partially only to the extent necessary for preventing adhesion during handling and conveyance. This partial application avoids the negative effects of complete coating while achieving the desired adhesion prevention.

Inventive Principle:
Principle #16Partial or excessive action

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 adhesion between rubber plugs, allowing for smooth conveyance using a part feeder and preventing sticking when packaged together, ensuring efficient handling and sealing performance.

Implementation Method 1

The surface of the cylindrical leg portion is coated with a synthetic resin film

Methodology Applied
Scientific EffectAdhesion: Adhesive

Implementation Method 2

the top surface of the discoid cap portion has a Shore A hardness in a range from 25 to 55 and a surface roughness Ra in a range from 2.5 μm to 10.5 μm

Methodology Applied
Scientific EffectAdhesion: Adhesive

Data Source

PatentEP2431295B1A rubber plug for a medical vial container
Publication Date: 2015.09.02 DAIKYO SEIKO LTD
  • EP2431295B1 patent drawingFigure 1
  • EP2431295B1 patent drawingFigure 2
  • EP2431295B1 patent drawingFigure 3

AI summary

A rubber plug (1) for a vial container (2) containing medicinal chemicals according to the present invention can be smoothly conveyed by a part feeder while preventing each other's adhesion. The top surface of a discoid cap portion (1A) has Shore A hardness of 25 -55 and surface roughness Ra of 2.5 -10.5µ m. Adherence of the top surface of the discoid cap portion (1A) is reduced by synergy effect. The rubber plug (1) can be smoothly conveyed by a part feeder in an inverted position which turns the top surface of the discoid cap portion (1A) to the conveying surface.