Lined Steel Aerosol Can Formulation for Corrosion and Fragrance Stability

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Solution Overview

Problem

Aerosol compositions in steel cans face corrosion, fragrance degradation, and discoloration due to high aqueous content and alkaline pH, limiting the fragrance palette and shelf life, and conventional corrosion inhibitors adversely affect fragrance stability.

Innovation Solution

A combination of a steel can with a liner and a formulation including nonionic and cationic surfactants, a mild corrosion inhibitor, and a pH adjuster within a specific pH range (8 to 10) to maintain corrosion, fragrance, and color stability, using a low VOC propellant like nitrogen to prevent corrosion reactions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If water is used to replace volatile solvents to reduce VOC content, then environmental compliance is improved, but corrosion of the steel can increases

Engineering Contradiction:
Improveenvironmental complianceVSAvoidcorrosion of steel can
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

A corrosion inhibitor is introduced as an intermediary substance that mediates between the aqueous formulation and the steel can. The corrosion inhibitor forms a protective layer on the metal surface, preventing direct contact between water and steel, thereby reducing corrosion while maintaining the low-VOC aqueous formulation.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The pH of the aqueous formulation is adjusted to a specific range (pH 6-8) to optimize corrosion protection. By controlling this critical parameter, the formulation becomes less aggressive toward the steel can, reducing corrosion rates while maintaining environmental compliance through low VOC content.

Inventive Principle:
Principle #35Parameter changes

2Object-affected harmful factors

If tin plating is applied to protect steel against corrosion, then corrosion resistance is improved, but tin dissolution into the aqueous formulation occurs over time causing fragrance degradation and discoloration

Engineering Contradiction:
Improvecorrosion resistanceVSAvoidfragrance stability and formulation color
Core Design Contradiction:
Object-affected harmful factorsVSStability of the object's composition

Solution Approach 1:

The tin plating layer is removed from the steel can system. By eliminating the tin intermediate layer, the design avoids the problem of tin dissolution into the aqueous formulation, thereby preventing fragrance degradation and discoloration while maintaining corrosion protection through alternative means.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The steel can is provided with an organic coating or polymeric laminate lining on the interior surface. This creates a localized protective barrier between the aqueous formulation and the steel, providing corrosion resistance without requiring tin plating, thus preventing tin dissolution and its associated problems.

Inventive Principle:
Principle #3Local quality

3Object-affected harmful factors

If conventional corrosion inhibitors are used to protect steel cans, then corrosion protection is improved, but fragrance stability deteriorates due to high alkaline pH

Engineering Contradiction:
Improvecorrosion protectionVSAvoidfragrance stability
Core Design Contradiction:
Object-affected harmful factorsVSStability of the object's composition

Solution Approach 1:

The pH of the aqueous formulation is precisely controlled within the range of pH 6-8, which is near neutral. This parameter optimization allows the use of milder corrosion inhibitors that provide adequate steel protection without creating highly alkaline conditions that would degrade fragrance compounds. The balanced pH maintains both corrosion protection and fragrance stability.

Inventive Principle:
Principle #35Parameter changes

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

This combination provides a broad fragrance palette with extended shelf life and stability, reducing the need for high-strength corrosion inhibitors, which minimizes alkaline pH effects on fragrances and prevents discoloration, ensuring the product remains effective and visually appealing.

Implementation Method 1

a nonionic surfactant film-forming corrosion inhibitor

Methodology Applied
Scientific EffectSurfactant film formation: Surfactant

Implementation Method 2

reduces the surface energy of the steel can to a level below that required for wetting by the aqueous formulation

Methodology Applied
Scientific EffectSurface energy reduction: Surface Tension

Implementation Method 3

The compressed gas propellant may be any suitable conventionally known compressed gas propellant, either oxygen or non-oxygen containing, including, but not limited to, nitrogen, argon, methane, ethane, air, nitrous oxide, carbon dioxide, or mixtures

Methodology Applied
Scientific EffectGas pressure: Pressure Increase

Data Source

PatentUS9040471B2Compressed gas aerosol composition comprising a non-ionic surfactant in a steel can
Publication Date: 2015.05.26 SC JOHNSON & SON INC

AI summary

An aqueous compressed gas aerosol formulation in combination with a lined steel can, which may also optionally be tin plated, to provide corrosion stability, fragrance stability and color stability. An aerosol formulation of particular advantage for use is an air and/or fabric treatment formulation. The combination provides a compatibility which allows for the ability to use a broader fragrance pallet for the air and/or fabric treatment formulation which is aqueous based in major proportion. The formulation includes, in addition to an aqueous carrier, a fragrance, nonionic surfactant(s) or a blend of nonionic surfactant(s) and cationic surfactant(s), a compressed gas propellant(s), pH adjuster(s), and corrosion inhibitor(s). The formulation has a pH of about 8 to less than 10. The corrosion inhibitor(s) is (are) mild in strength and used in a minor amount.