Razor Blade Printing Material Lubrication

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Solution Overview

Problem

Conventional razor blades cause excessive nicking and cutting during wet shaving due to inadequate lubrication, as the polymer coating is often inconsistent and only applied to the tip, leaving uncoated areas to contact the skin, resulting in frictional resistance and discomfort.

Innovation Solution

A method of applying a telomer-based printing material with anti-foaming properties onto the razor blade using inkjet printing, which covers both sides of the blade, providing a lubricious coating that minimizes friction and improves glide, comprising 0.25% to 50% solids by weight of telomer, with a viscosity of 2 to 25 centipoise, and including glycerol as a viscosity modifier.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If conventional spray coating is used to apply polymer coating to razor blade tips, then the coating process is simple and fast, but the coating is inconsistent and only covers the tip area, leaving uncoated areas that cause friction and discomfort

Engineering Contradiction:
Improvecoating consistency and coverageVSAvoidcoating application process
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The patent replaces the conventional spray coating mechanical system with a digital printing system. The printing apparatus uses print heads with nozzles that deposit polymer material in controlled droplets or patterns directly onto the blade surface, enabling precise coverage control without the overspray and inconsistency issues of spray coating

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent changes the physical state and delivery method of the polymer coating material. Instead of aerosolized spray, the polymer is delivered as controlled droplets or printed patterns through print heads, allowing precise control of coating location, thickness, and coverage area. The printing process parameters (droplet size, spacing, pattern) can be adjusted to optimize coating performance

Inventive Principle:
Principle #35Parameter changes

2Productivity

If the number of razor blades per cartridge is increased, then the shaving coverage is improved, but the total blade drag on skin increases, causing more friction and discomfort

Engineering Contradiction:
Improveshaving coverageVSAvoidblade drag on skin
Core Design Contradiction:
ProductivityVSForce

Solution Approach 1:

The patent applies local quality by providing different surface properties at different locations on the blade. The polymer coating is applied selectively to specific areas (such as the tip or edges) where skin contact occurs, while other areas remain uncoated. This localized coating approach reduces friction at critical contact points without requiring coating of the entire blade surface

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The patent uses a thin film polymer coating that conforms to the blade geometry. This thin film layer provides lubrication where needed while maintaining the blade's structural integrity and cutting performance. The flexible nature of the thin film allows it to adapt to the blade's shape and the skin's surface during shaving

Inventive Principle:
Principle #30Flexible shells and thin films

3Strength

If conventional PVD coating is applied to blade edges, then the blade edge strength is improved, but the coating does not provide sufficient lubrication, resulting in excessive pulling and irritation

Engineering Contradiction:
Improveblade edge strengthVSAvoidskin irritation and pulling
Core Design Contradiction:
StrengthVSObject-affected harmful factors

Solution Approach 1:

The patent uses composite materials by combining the hard, strength-providing PVD coating layer with a separate polymer lubrication layer. The PVD coating (such as chromium or titanium nitride) provides edge strength and durability, while the overlaying polymer coating (such as PTFE or telomer) provides lubrication and reduces skin irritation. This multi-layer composite structure delivers both mechanical strength and lubrication benefits

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The patent introduces a polymer coating as an intermediary layer between the metal blade and the skin. This intermediary polymer layer reduces direct contact between the metal blade edge and the skin, minimizing irritation and pulling. The polymer acts as a mediator that allows the blade to cut hair effectively while protecting the skin from direct metal contact

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 solution enhances shaving comfort and safety by reducing nicks and cuts, maintaining improved lubrication and rinsability of the razor cartridge, with the printed material extending along the blade's length and maintaining its effectiveness through controlled droplet size and spacing for optimal wear resistance.

Implementation Method 1

A method of making a razor blade for a razor cartridge includes the steps of providing at least one razor blade... providing at least one printing material... and printing the at least one printing material onto at least the tip of the at least one razor blade

Methodology Applied
Scientific EffectInkjet printing:

Implementation Method 2

A thin polymer coating on the blade edge is generally lubricious with an inherent hydrophobic nature which causes a film of water droplets of a microscopic scale to remain on the cutting blade edge. This in turn enhances the effect of the polymer coating, and can reduce the frictional resistance between the blade edge and the skin

Methodology Applied
Scientific EffectLubrication: Lubrication

Implementation Method 3

The at least one printing material comprises an anti-foaming material

Methodology Applied
Scientific EffectAnti-foaming: Antifoam

Implementation Method 4

with a viscosity of 2 to 25 centipoise, and including glycerol as a viscosity modifier

Methodology Applied
Scientific EffectViscosity modification:

Data Source

PatentEP3478462B1Printed razor blades
Publication Date: 2023.06.14 THE GILLETTE CO
  • EP3478462B1 patent drawingFigure 1
  • EP3478462B1 patent drawingFigure 2
  • EP3478462B1 patent drawingFigure 3A

AI summary

A razor blade having an improved lubricious material deposited thereon and a method of making a razor blade for a razor cartridge having such a material disposed thereon are described herein. A novel printing process and printing material are provided where at least one printing material is deposited on one or more razor blades via a printing process which includes one or more print heads for printing the at least one printing material and forming at least one printed object on a tip or one or more sides of the razor blade. The printing material may comprise about of about 0.25% solid to about 50% solids by weight of composition of telomer and further desirably comprises glycerol and/or an antifoam material. Optimizing coverage of the printing material may be achieved by changing materials, print heads, the firing frequency of the print head or angling or rotating the print heads.