Polymer Part Surface Dyeing for Alcohol-Fast Medical Device Coating

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Solution Overview

Problem

Conventional surface dyeing methods for polymer medical parts, which involve elevated temperatures, result in dimensional changes and incompatibility with alcohol-based cleaning solutions, leading to dye leaching or transfer, making them unsuitable for medical settings.

Innovation Solution

A method involving a surface treatment solution with a solvent and additive, followed by submersion, air drying, vapor polishing with hexafluoroisopropanol, and a final wash in a surfactant and water solution to create an alcohol-fast coating that binds the dye or additive within the polymer, preventing leaching or transfer.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional acid-based dyeing under heat near 95°C is used, then color is imparted to polymer parts, but dimensional change occurs and dye leaches under alcohol exposure

Engineering Contradiction:
Improvedye fastness to alcoholVSAvoiddyeing temperature
Core Design Contradiction:
ReliabilityVSTemperature

Solution Approach 1:

The patent changes the fundamental parameters of the dyeing process by using room temperature conditions instead of elevated temperatures, and by substituting conventional acid-based dyes with dyes that have carboxylic acid groups that can form hydrogen bonds with the polymer. This parameter change resolves the contradiction by achieving dye fastness without thermal exposure that causes dimensional changes.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent creates a composite interaction between the dye molecules and the polymer matrix through specific molecular interactions (hydrogen bonding between carboxylic acid groups of the dye and functional groups of the polymer). This composite approach ensures the dye is firmly anchored to the polymer surface, preventing leaching under alcohol exposure while avoiding high temperature processing.

Inventive Principle:
Principle #40Composite materials

2Manufacturing precision

If conventional acid-based dyeing under heat near 95°C is used, then color is imparted to polymer parts, but dimensional change occurs

Engineering Contradiction:
Improvedimensional stabilityVSAvoiddyeing temperature
Core Design Contradiction:
Manufacturing precisionVSTemperature

Solution Approach 1:

The patent fundamentally changes the temperature parameter from elevated heat (95°C) to room temperature processing. This parameter change directly resolves the contradiction by eliminating thermal exposure that causes dimensional changes in polymer parts while still achieving effective color impartation through enhanced molecular interaction mechanisms.

Inventive Principle:
Principle #35Parameter changes

3Reliability

If dye is imparted by conventional process, then color is achieved, but dye readily leaves the part under alcohol exposure

Engineering Contradiction:
Improvedye fastness to alcoholVSAvoiddye transfer to cleaning wipes
Core Design Contradiction:
ReliabilityVSObject-generated harmful factors

Solution Approach 1:

The patent changes the chemical parameters of the dye molecules by selecting dyes with carboxylic acid groups that can form strong hydrogen bonds with the polymer surface. This chemical parameter change creates a durable bond that prevents dye transfer to alcohol-based cleaning wipes, resolving the contradiction between achieving color and preventing dye migration.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent introduces hydrogen bonding as an intermediary mechanism that mediates the interaction between the dye and the polymer surface. This intermediary bonding mechanism creates a strong attachment that prevents dye leaching under alcohol exposure, while the dye molecules themselves serve as the coloring agents.

Inventive Principle:
Principle #24Intermediary (Mediator)

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 method produces a polymer part with a surface additive that remains adhered and resistant to alcohol solutions, ensuring cleanliness and aesthetic appeal without exposing parts to high temperatures.

Implementation Method 1

submerging a polymer part in the surface treatment solution for a set time period in order to coat the surface of the part with the additive

Methodology Applied
Scientific EffectAbsorption: Absorption (physical)

Implementation Method 2

vapor polishing the part by exposing an outer surface to vaporized hexafluoroisopropanol (HFIP) under vacuum in order to encapsulate and bind the additive within the polymer through entanglement

Methodology Applied
Scientific EffectVapor polishing:

Implementation Method 3

air drying the part in which the surface treatment solution is chosen such as to accelerate the drying process

Methodology Applied
Scientific EffectEvaporation: Evaporation

Data Source

PatentEP4241991A1Process of coloring or treating the surface of polymer parts
Publication Date: 2023.09.13 HOWMEDICA OSTEONICS CORP
  • EP4241991A1 patent drawingFigure 1
  • EP4241991A1 patent drawingFigure 2A
  • EP4241991A1 patent drawingFigure 2B

AI summary

Provided is a method of dyeing or otherwise surface treating a polymer part so as to provide a treated polymer part with a surface additive which has wash fastness with respect to alcohol solutions and therefore does not leach or transfer in response to contact with alcohol. The method includes preparing a surface treatment solution comprising a solvent and the surface additive; submerging a polymer part in the surface treatment solution for a set time period before in order to coat the surface of the part with the additive; air drying the part; vapor polishing the part by exposing an outer surface to vaporized hexafluoroisopropanol in order to bind the additive within the polymer; and finally washing the fixed coated part in a surfactant and water solution to produce a finished surface treated polymer part.