Radiation Resistant Silicone Formulations for Medical Devices

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Solution Overview

Problem

Traditional sterilization methods, particularly irradiation, cause cross-linking in silicone materials used in medical devices, leading to surface bonding issues in fluid flow devices, which complicates manufacturing and reduces the ability to control fluid flow.

Innovation Solution

A silicone formulation incorporating a non-polar polyalkylsiloxane matrix with a polar gamma radiation-resistant component, such as low molecular weight silicone oils with halide or phenyl functional groups, that remains unreactive during sterilization, preventing cross-linking and maintaining device functionality.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If irradiation sterilization is used on polyalkylsiloxane devices, then sterility is achieved, but cross-linking occurs causing surface bonding and loss of fluid flow control

Engineering Contradiction:
ImprovesterilityVSAvoidfluid flow control
Core Design Contradiction:
ReliabilityVSEase of operation

Solution Approach 1:

A fluorinated silane coupling agent is introduced as an intermediary substance between the polyalkylsiloxane matrix and the radiation sterilization process. The coupling agent absorbs the radiation energy and prevents direct interaction between gamma rays and the silicone polymer chains, thereby eliminating cross-linking while preserving sterility. This mediator approach allows both sterilization and functional integrity to be achieved simultaneously.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The chemical composition parameters of the silicone formulation are modified by incorporating fluorinated silane compounds at specific concentrations (0.1-10 wt%). This parameter change alters the material's radiation response characteristics, making it resistant to cross-linking while maintaining its original physical properties and fluid flow control capabilities after sterilization.

Inventive Principle:
Principle #35Parameter changes

2Ease of operation

If exterior lubricants are applied to prevent surface bonding, then fluid flow control is maintained, but manufacturing complexity and cost increase

Engineering Contradiction:
Improvefluid flow controlVSAvoidmanufacturing process
Core Design Contradiction:
Ease of operationVSDevice complexity

Solution Approach 1:

The silicone formulation is modified to be self-protecting against radiation-induced cross-linking through the incorporation of fluorinated silane coupling agents. This self-service approach eliminates the need for external lubricants or coatings, as the material inherently resists surface bonding during sterilization. The manufacturing process is simplified to a single-step formulation mixing, removing complex multi-step lubrication procedures.

Inventive Principle:
Principle #25Self-service

3Reliability

If prepackaged sterilization is used, then sterility is maintained, but access to apply lubricants is prevented

Engineering Contradiction:
ImprovesterilityVSAvoidlubricant application
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The fluorinated silane coupling agent is incorporated into the silicone formulation during the initial manufacturing stage, before packaging. This preliminary action ensures the material has built-in radiation resistance from the outset, eliminating the need for subsequent lubricant application steps that would be impossible with prepackaged sterilization. The formulation is prepared once with all necessary components, and then sterilized directly in its final packaged form.

Inventive Principle:
Principle #10Preliminary 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 formulation allows for effective sterilization of medical devices without external lubricants, maintaining the reseal performance and burst pressure of fluid control devices, reducing the risk of surface bonding and improving manufacturing efficiency.

Implementation Method 1

A polymeric material formed of a composition comprising polyalkylsiloxane forming a polymer matrix and a gamma radiation resistant component in an amount of 0.1 wt% to 20 wt% based on the weight of the polyalkylsiloxane

Methodology Applied
Scientific EffectGamma radiation absorption: Absorption (EM radiation)

Implementation Method 2

The gamma radiation resistant component is a silicone oil including halide or phenyl functional groups

Methodology Applied
Scientific EffectRadiation resistance: Radiation

Data Source

PatentEP1907479B1Radiation resistant silicone formulations and medical devices formed of same
Publication Date: 2018.10.03 SAINT GOBAIN PERFORMANCE PLASTICS CORP
  • EP1907479B1 patent drawingFigure 1~5
  • EP1907479B1 patent drawingFigure 6~8
  • EP1907479B1 patent drawingFigure 9~10

AI summary

The disclosure is directed to a polymeric material formed of a composition including polyalkylsiloxane and a radiation resistant component. The radiation resistant component is included in an amount of about 0.1 wt % to about 20 wt % based on the weight of the polyalkylsiloxane.