Solventless Silicone Coating for Prefilled Syringe Sliding

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Solution Overview

Problem

Prefilled syringes face challenges in maintaining stable liquid medicine discharge under high pressure and accuracy over time, with existing solutions either compromising on liquid-tightness and sliding performance or using hazardous organic tin compounds as catalysts.

Innovation Solution

A medical appliance with a slidable coating layer formed from a solventless-type hardening silicone-based resin, eliminating the need for organic tin compounds and ensuring stable sliding performance without lubricants, which prevents sticking and allows for smooth initial motion during use.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If silicone oil or lubricant is applied to the sliding portion to enhance sliding performance, then sliding performance is improved, but the liquid medicine deteriorates due to interaction with the lubricant during long-term storage

Engineering Contradiction:
Improvesliding performanceVSAvoidstability of liquid medicine
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

The invention extracts and removes the harmful lubricant (silicone oil) from the system entirely. Instead of applying lubricant to the sliding portion, the gasket is designed with a fluorine resin coating layer that provides low friction properties inherently, eliminating the need for separate lubricant application and preventing interaction between lubricant and liquid medicine during storage

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The invention uses a composite structure consisting of a gasket body made of elastic body material and a coating layer made of fluorine resin. This composite material combination provides both the elasticity needed for sealing and the low friction properties needed for smooth sliding, without requiring additional lubricants that could interact with the liquid medicine

Inventive Principle:
Principle #40Composite materials

2Reliability

If fluorine resin coating layer is applied to eliminate lubricant use, then liquid medicine stability is improved, but sliding performance under high pressure and at low speeds deteriorates

Engineering Contradiction:
Improvestability of liquid medicineVSAvoidsliding performance
Core Design Contradiction:
ReliabilityVSEase of operation

Solution Approach 1:

The invention optimizes the parameters of the fluorine resin coating layer, specifically controlling the thickness to 1-30 μm and selecting appropriate fluorine resin materials with specific friction coefficients. These parameter adjustments ensure the coating provides sufficient sliding performance even under high pressure and low speed conditions while maintaining liquid medicine stability

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The invention applies the fluorine resin coating layer selectively to specific portions of the gasket where sliding contact occurs, rather than coating the entire gasket. This localized application ensures low friction properties are concentrated where needed for sliding performance while maintaining the elastic body's sealing properties in other areas

Inventive Principle:
Principle #3Local quality

3Ease of manufacture

If organic tin compound is used as catalyst for coating layer formation, then coating layer formation is improved, but harmful effects and environmental concerns are introduced

Engineering Contradiction:
Improvecoating layer formationVSAvoidharmful effects of organic tin compound
Core Design Contradiction:
Ease of manufactureVSObject-affected harmful factors

Solution Approach 1:

The invention replaces the harmful organic tin compound catalyst with a platinum-based catalyst or alternative catalytic system. This substitution eliminates the harmful effects and environmental concerns associated with organic tin compounds while maintaining or improving the coating layer formation process and resulting coating quality

Inventive Principle:
Principle #22Blessing in disguise (Convert harm into benefit)

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 solventless coating layer provides favorable sliding properties at low speeds, prevents particle separation, and ensures consistent medication delivery without the risks associated with organic tin compounds, enhancing both the sliding and sealing performance of the syringe.

Implementation Method 1

a slidable coating layer which is formed of a composition containing a solventless-type hardening silicone-based resin

Methodology Applied
Scientific EffectChemical reaction (crosslinking): Chemical Bonding

Data Source

PatentEP2692366B1Medical instrument with slidable coating layer, and syringe
Publication Date: 2017.02.01 TERUMO KK
  • EP2692366B1 patent drawingFigure 1~2
  • EP2692366B1 patent drawingFigure 3~4
  • EP2692366B1 patent drawingFigure 5

AI summary

A medical appliance of the present invention having a slidable coating layer moves in contact with an inner surface of a medical member or that of a lumen. The medical appliance has the slidable coating layer formed at a part thereof which contacts the medical member or the lumen. The slidable coating layer is formed of a composition containing a solventless-type hardening silicone-based resin.