Bar Soap Discoloration Control via pH Adjustment
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Solution Overview
Problem
Bar soap comprising pyrithione sources often experiences discoloration due to reactions with metallic ions during manufacturing and storage, leading to aesthetic and regulatory issues, with existing solutions being costly, unsafe, or ineffective.
Innovation Solution
Incorporating a pH adjusting agent such as ammonia solution, triethanolamine, or sodium hydroxide to raise the pH of the bar soap to greater than or equal to 10.7, inhibiting the formation of colored precipitates with ferric or cupric ions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If pyrithione source is used in bar soap, then antimicrobial efficacy is provided, but discoloration occurs due to reaction with metal ions
Solution Approach 1:
The patent introduces pH adjusting agents (such as ammonia solution, triethanolamine, diethanolamine, monoethanolamine, potassium hydroxide, sodium hydroxide, sodium phosphate dibasic, or soluble carbonate salts) as intermediary substances that mediate between the pyrithione source and metal ions. By adjusting the pH to 10.7 or higher, these agents prevent direct harmful reactions between pyrithione and metal ions, thereby eliminating discoloration while preserving antimicrobial efficacy.
Solution Approach 2:
The patent changes the pH parameter of the bar soap formulation to 10.7 or higher. This parameter change fundamentally alters the chemical environment, preventing the formation of colored precipitates between pyrithione and metal ions. The high pH condition stabilizes the pyrithione compound, allowing it to maintain antimicrobial properties without undergoing discoloration reactions.
2Object-affected harmful factors
If zinc-containing materials are used to prevent discoloration, then discoloration is reduced, but cost increases and regulatory limitations apply
Solution Approach 1:
Instead of adding costly zinc-containing materials, the patent changes the pH parameter to 10.7 or higher using conventional pH adjusting agents. This parameter change approach eliminates discoloration through chemical mechanism modification rather than material addition, avoiding both cost increases and regulatory limitations associated with zinc content.
Solution Approach 2:
The patent employs conventional, inexpensive pH adjusting agents (such as ammonia solution, sodium hydroxide, or carbonate salts) that are readily available and cost-effective. These agents provide the necessary pH adjustment without the high cost and regulatory burden of zinc-containing materials, representing a more economical solution to the discoloration problem.
3Object-affected harmful factors
If reducing agents are used to prevent discoloration, then discoloration is reduced, but formulation complexity increases due to interactions with other ingredients
Solution Approach 1:
The patent avoids using reducing agents entirely and instead changes the pH parameter to 10.7 or higher. This approach prevents discoloration through a different chemical mechanism (preventing oxidation reactions at high pH) that does not involve the complex interactions and formulation challenges associated with reducing agents.
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
Significantly reduces discoloration, maintaining the original color and ensuring safety and regulatory compliance while being cost-effective.
Implementation Method 1
Incorporating a pH adjusting agent such as ammonia solution, triethanolamine, or sodium hydroxide to raise the pH of the bar soap to greater than or equal to 10.7, inhibiting the formation of colored precipitates with ferric or cupric ions
Data Source
AI summary
A bar soap comprising a pyrithione source, a soap surfactant, and a pH adjusting agent selected from a group consisting of ammonia solution, triethanolamine, diethanolamine, monoethanolamine, potassium hydroxide, sodium hydroxide, soluble carbonate salts, and combinations thereof, wherein the bar soap attains a pH of greater than or equal to 10.7. A process of inhibiting the formation of a discoloration in a bar soap comprising pyrithione sources by adding pH adjusting agent to attain a pH of greater than or equal to 10.7. A process of inhibiting the formation of a discoloration in a bar soap caused by dissolved ferric ions and/or cupric ions and pyrithione sources in the bar, comprising the step of adding from about 0.3% to about 20% soluble carbonate salt during manufacturing of the bar soap.