Razor Blade Edge Polyfluorocarbon Coating Process

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Solution Overview

Problem

Conventional razor blades require excessive force for shaving, leading to discomfort and irritation, and existing polyfluorocarbon coatings do not maintain low cutting forces over the life of the blade.

Innovation Solution

A method involving a polyfluorocarbon coating process where a first polytetrafluoroethylene coating is applied, heated, solvent-treated to thin it, and then re-coated with a second polytetrafluoroethylene layer, followed by further heating and solvent treatment to achieve a thin, uniform, and well-adhered coating that reduces cutting forces and maintains improved shaving performance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-affected harmful factors

If a polyfluorocarbon coating is applied to reduce cutting forces, then initial shave comfort is improved, but the coating wears and adhesion is lost during subsequent shaves

Engineering Contradiction:
Improvecutting forcesVSAvoidcoating adhesion
Core Design Contradiction:
Object-affected harmful factorsVSReliability

Solution Approach 1:

The patent applies multiple solvent treatments at different stages (after first coating, after second coating) to precisely control the coating thickness and molecular structure. By changing the solvent treatment parameters, the coating is transformed from a thick, non-uniform state to a thin, uniform state with optimal adhesion and low cutting forces that are maintained throughout the blade's life

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The coating process is divided into multiple discrete stages: first coating application, first heating, first solvent treatment, second coating application, second heating, and second solvent treatment. This segmentation allows each stage to be optimized independently, ensuring both initial comfort and long-term reliability

Inventive Principle:
Principle #1Segmentation

2Object-affected harmful factors

If a thick polyfluorocarbon coating is applied to reduce cutting forces, then initial shave comfort is improved, but the coating becomes non-uniform and excessive

Engineering Contradiction:
Improvecutting forcesVSAvoidcoating uniformity
Core Design Contradiction:
Object-affected harmful factorsVSManufacturing precision

Solution Approach 1:

The patent extracts excess coating material through solvent treatment steps. After each coating application and heating cycle, a solvent is applied to dissolve and remove the non-adherent portion of the coating, leaving only the thin, uniform, well-adhered layer that provides optimal performance

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent performs preliminary coating applications followed by heating and solvent treatment before the final coating. This preliminary action creates a base layer with optimal adhesion properties, ensuring that the final thin coating remains uniform and adherent throughout the blade's life

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 process results in a razor blade with significantly lower initial and sustained cutting forces, reducing discomfort and improving shave quality over the life of the blade, with reduced nicks and enhanced comfort.

Implementation Method 1

heating the coating obtained to melt, partially melt or sinter the fluorocarbon polymer

Methodology Applied
Scientific EffectHeating: Heating

Implementation Method 2

heating the coating obtained to melt, partially melt or sinter the fluorocarbon polymer

Methodology Applied
Scientific EffectSintering: Sintering

Implementation Method 3

treating the coated blade edge with a solvent to thin the coating

Methodology Applied
Scientific EffectSolvation: Solvation

Implementation Method 4

the critical temperature or boiling point of the first and second solvents is above the dissolution temperature for the first and second polyfluorocarbons in the first and second solvents

Methodology Applied
Scientific EffectDissolution:

Data Source

PatentEP3164226B1Method of treating razor blade cutting edges
Publication Date: 2021.05.19 THE GILLETTE CO
  • EP3164226B1 patent drawingFigure 1
  • EP3164226B1 patent drawingFigure 1A
  • EP3164226B1 patent drawingFigure 2

AI summary

The present invention relates to razor blade cutting edges and methods of producing edges exhibiting improved shave performance longevity and lower cutting forces. Conventional razor blades have increasing cutting forces with use due to the outer coating wear and adhesion loss. Blade edges produced according to the novel process exhibit significantly lower cutting forces when subjected to wool felt cutting shaving simulation, which correlates to more comfortable shaves initially and over the life of the blades. The present invention treats razor blade edges having a first adherent polyfluorocarbon coating with a first solvent to partially remove the polyfluorocarbon coating, adds a second polyflourocarbon coating, heats, and treats the blade edge with a second solvent providing a final blade edge having a thin, uniform polyfluorocarbon coating. Preferred solvents include perfluoroalkanes, perfluorocycloalkanes, and perfluoroaromatic compounds having a critical temperature or boiling point above the dissolution temperature for the polyfluorocarbon in the solvent.