Copper-Clad Cookware Sidewalls With Tarnish-Resistant Clear Coating

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Solution Overview

Problem

Copper cookware tarnishes easily when exposed to heat and liquids, making it difficult to clean and maintain, which compromises its aesthetic appeal and cooking performance, and existing solutions either hide the copper or use coatings that are not thermally stable or expensive.

Innovation Solution

A cookware design with a copper cladding on the sidewalls that is flush with a stainless steel bottom cladding, combined with a heat-resistant transparent organic lacquer coating to prevent tarnishing and facilitate cleaning, while maintaining the copper's appearance and thermal conductivity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Illumination intensity

If copper layers are exposed on the exterior to maintain aesthetic appearance and thermal conductivity, then the unique reddish-gold appearance and cooking performance are preserved, but the copper tarnishes readily on exposure to heat and liquids requiring extra cleaning effort

Engineering Contradiction:
Improveaesthetic appearanceVSAvoidcleaning effort
Core Design Contradiction:
Illumination intensityVSEase of operation

Solution Approach 1:

A clear protective coating is applied as an intermediary layer between the exposed copper exterior and the environment. This coating acts as a mediator that prevents direct contact between copper and tarnishing agents (heat, liquids, moisture) while maintaining the copper's aesthetic appearance and thermal conductivity properties.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Reliability

If protective coatings are applied to prevent tarnishing, then the copper appearance is maintained, but the coatings are either expensive (inorganic) or not thermally stable (organic lacquers) at high cooking temperatures

Engineering Contradiction:
Improvetarnish preventionVSAvoidthermal stability
Core Design Contradiction:
ReliabilityVSTemperature

Solution Approach 1:

The patent modifies the chemical composition and physical properties of the protective coating to achieve optimal balance between tarnish prevention and thermal stability. By adjusting coating parameters such as thickness, cross-linking density, and chemical structure, the coating can withstand high cooking temperatures while maintaining its protective function against tarnishing.

Inventive Principle:
Principle #35Parameter changes

3Illumination intensity

If inorganic coatings are used to achieve reflective golden metal appearance, then the aesthetic quality is improved, but the coatings are expensive and not thermally or chemically stable at high cooking temperatures

Engineering Contradiction:
Improvereflective appearanceVSAvoidcost and manufacturing complexity
Core Design Contradiction:
Illumination intensityVSEase of manufacture

Solution Approach 1:

The patent employs a cost-effective organic protective coating that, while having shorter thermal stability compared to inorganic coatings, provides sufficient protection for the intended use. This approach replaces expensive inorganic coatings with a more economical solution that meets the functional requirements of cookware applications.

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

4Reliability

If copper is buried in metal cladding to prevent tarnishing, then the tarnishing problem is solved, but the unique copper appearance and thermal performance benefits are eliminated

Engineering Contradiction:
Improvetarnish resistanceVSAvoidcopper appearance
Core Design Contradiction:
ReliabilityVSIllumination intensity

Solution Approach 1:

The protective coating is applied selectively to the exterior copper surfaces that are exposed to environmental conditions. This localized protection approach maintains the copper's aesthetic appearance and thermal conductivity in visible areas while providing tarnish resistance only where needed, rather than burying the entire copper structure.

Inventive Principle:
Principle #3Local quality

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 design prevents tarnishing and maintains the copper's appearance and cooking performance by using a heat-resistant coating on the exposed copper cladding, which is easier to clean and less prone to dirt accumulation, reducing maintenance efforts.

Implementation Method 1

a heat-resistant transparent organic lacquer coating to prevent tarnishing

Methodology Applied
Scientific EffectProtective coating: Coatings

Implementation Method 2

copper cookware is appreciated for its high thermal conductivity

Methodology Applied
Scientific EffectThermal conductivity: Conduction (thermal)

Data Source

PatentEP1913852B1Cookware with tarnish protected copper exterior
Publication Date: 2010.05.12 MEYER INTELLECTUAL PROPERTIES LIMITED
  • EP1913852B1 patent drawingFigure 1a~1b
  • EP1913852B1 patent drawingFigure 2
  • EP1913852B1 patent drawingFigure 3

AI summary

An article of cookware in the form of a cooking vessel that exposes only a portion of a copper inner layer (6) on the upper portion of the exterior sidewall. The layer does not change color or tarnish as it is sufficiently distal from the bottom (2) of the cooking vessel that it is not subject to direct heat and oxidation during normal use. The unique bright colour of the native copper is further protected from tarnish caused by fingerprint by a protective coating that can withstand moderate heating.