Fluoropolymer Coating Adhesion on Metallic Substrates

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Solution Overview

Problem

Existing medical devices with metallic substrates face challenges in achieving strong and durable adhesion of fluorine-containing polymer coatings, which is crucial for maintaining mechanical integrity and drug release efficacy, especially under wet conditions.

Innovation Solution

A polymeric region comprising a fluorine-containing polymer and an adhesion promoting copolymer that covalently or non-covalently bonds with the metallic substrate, using monomers such as vinylidene fluoride, hexafluoropropylene, acrylate, and methacrylate, to enhance adhesion and interaction between the polymer and substrate, optionally including a drug for therapeutic release.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a fluorine-containing polymer coating is applied to a metallic substrate, then the coating provides good mechanical integrity and drug release efficacy, but the adhesion between the coating and substrate is insufficient, especially under wet conditions

Engineering Contradiction:
Improvecoating adhesionVSAvoidbond strength between coating and substrate
Core Design Contradiction:
ReliabilityVSStrength

Solution Approach 1:

The patent introduces an adhesion promoter layer as an intermediary between the fluorine-containing polymer coating and the metallic substrate. This promoter layer contains functional groups that can chemically interact with both the metal substrate and the fluoropolymer, thereby mediating the adhesion interface and improving bonding strength under wet conditions

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent creates a composite structure consisting of multiple layers: the metallic substrate, an adhesion promoter layer with specific chemical composition, and the fluorine-containing polymer coating. This composite material system combines the advantages of each layer to achieve both strong adhesion and the desired coating properties

Inventive Principle:
Principle #40Composite materials

2Productivity

If the coating is made thinner to improve drug release, then the drug release efficacy is enhanced, but the mechanical integrity and adhesion of the coating are compromised

Engineering Contradiction:
Improvedrug release rateVSAvoidcoating mechanical integrity
Core Design Contradiction:
ProductivityVSStrength

Solution Approach 1:

The patent applies different properties to different regions of the coating system. The adhesion promoter layer provides strong bonding capability at the substrate interface, while the fluorine-containing polymer layer provides drug release functionality. This local differentiation allows thin coating design without compromising overall integrity

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The patent segments the coating into functionally distinct layers: an adhesion promoter layer for bonding and a fluorine-containing polymer layer for drug release. This segmentation allows each layer to be optimized for its specific function, enabling thin overall design while maintaining mechanical integrity through the promoter layer

Inventive Principle:
Principle #1Segmentation

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 provides improved adhesion of polymeric regions to metallic substrates, maintaining mechanical integrity and ensuring effective drug release, even under wet conditions, thereby enhancing the performance and longevity of medical devices like stents.

Implementation Method 1

an adhesion promoting copolymer that comprises (i) a first monomer that covalently or non-covalently bonds with the metallic substrate

Methodology Applied
Scientific EffectCovalent bonding: Chemical Bonding

Implementation Method 2

an adhesion promoting copolymer that comprises (i) a first monomer that covalently or non-covalently bonds with the metallic substrate

Methodology Applied
Scientific EffectNon-covalent bonding: Chemical Bonding

Data Source

PatentEP2331157B1Medical devices having fluorine-containing polymer coatings with improved adhesion
Publication Date: 2016.02.24 BOSTON SCIENTIFIC SCIMED INC
  • EP2331157B1 patent drawingFigure 1A~1B
  • EP2331157B1 patent drawingFigure 2A~2C
  • EP2331157B1 patent drawing

AI summary

According to an aspect of the present invention, medical devices are provided which include a metallic substrate and a polymeric region disposed over and in contact with the metallic substrate. The polymeric region includes (a) a fluorine-containing polymer that contains at least one type of fluorine-containing monomer selected from a vinylidene fluoride monomer, a hexafluoropropylene monomer, and a combination thereof, and (b) an adhesion promoting copolymer that contains (i) at least one type of first monomer that covalently or non-covalently bonds with the metallic substrate and (ii) at least one type of second monomer selected from acrylate monomers, methacrylate monomers, fluorine-containing monomers, and combinations thereof.