Synthetic Detergent Bar Efflorescence Control via PEG and Isethionate Ranges

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Solution Overview

Problem

Synthetic detergent bars structured with polyethylene glycol and alkali metal isethionate often experience efflorescence, a visually unappealing phenomenon of crystalline solid formation on the surface, which is unacceptable for consumer products.

Innovation Solution

Defining specific ranges for the amounts of alkali metal isethionate, polyalkylene glycol, and water in the final bar composition, using experimentally determined multiplication factors to ensure stability and homogeneity, thereby eliminating efflorescence.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If electrolyte (sodium isethionate) is incorporated into syndet bars structured with water-soluble structurant (polyethylene glycol) to enhance firmness and robustness during manufacture, then the bar structure becomes harder and more robust, but crystalline solids form on the surface upon storage (efflorescence)

Engineering Contradiction:
Improvebar firmness and robustnessVSAvoidefflorescence (crystalline solid formation on surface)
Core Design Contradiction:
StrengthVSObject-generated harmful factors

Solution Approach 1:

The patent applies parameter changes by precisely controlling the concentration ranges of electrolyte (0.1-4.8% sodium isethionate), water-soluble structurant (6.8-54% polyethylene glycol), and water (2.7-13.5%) in the bar formulation. By optimizing these parameters within specific ranges, the patent achieves enhanced bar firmness while preventing efflorescence, as the balanced composition maintains homogeneity and stability during storage.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent uses composite materials by combining electrolyte (sodium isethionate), water-soluble structurant (polyethylene glycol), and water in a specific composite formulation. This composite approach creates a synergistic effect where the combination of ingredients, rather than individual components, achieves the desired bar properties - firmness without efflorescence - through their interactive behavior in the formulated system.

Inventive Principle:
Principle #40Composite materials

2Reliability

If the amount of soap is reduced in synthetic detergent bars to maintain clinical mildness, then the formulation becomes milder, but lather formation and bar structure become insufficient

Engineering Contradiction:
Improveclinical mildnessVSAvoidpoor lather formation and insufficient bar structure
Core Design Contradiction:
ReliabilityVSObject-generated harmful factors

Solution Approach 1:

The patent uses water-soluble structurant (polyethylene glycol) as an intermediary substance that bridges the gap between reduced soap content and maintained performance. The PEG acts as a mediator that provides structural support and facilitates lather formation even when soap content is reduced, enabling the bar to maintain clinical mildness without sacrificing functional properties.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent employs composite materials by formulating a combination of synthetic detergent, water-soluble structurant (polyethylene glycol), electrolyte, and water. This composite formulation compensates for reduced soap content by incorporating PEG, which contributes to both bar structure and lather formation, thereby maintaining clinical mildness while preserving functional performance.

Inventive Principle:
Principle #40Composite materials

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 specified ranges for these components ensure that the final bar composition remains stable and homogeneous, preventing efflorescence and maintaining a pleasant user experience while maintaining lather and structural integrity.

Implementation Method 1

polyethylene glycols are advantageous because they provide a water-soluble matrix that can still be extruded

Methodology Applied
Scientific EffectWater solubility: Solvation

Implementation Method 2

electrolyte (e.g., sodium isethionate or salt NaCl) is typically incorporated into bar formulations to enhance firmness and robustness during manufacture

Methodology Applied
Scientific EffectElectrolyte interaction: Electrolyte

Implementation Method 3

because of the physical interactions between PEGs, surfactants, co-surfactants and water, the formulations still tend to be physically softer

Methodology Applied
Scientific EffectPhysical interactions: Solvation

Data Source

PatentUS11384320B2Synthetic detergent bars
Publication Date: 2022.07.12 CONOPCO INC

AI summary

A bar composition comprising: a) 10%-60% synthetic (non-soap) surfactant; b) 0%-50% fatty acid and soap wherein total fatty acid soap is less than 60% of total synthetic surfactant; c) 6.8%-54% water-soluble structurant, selected from • polyalkylene oxides having MW 1,500-10,000, • PEO-PPO blockcopolymers, wherein the water soluble structurant has a melting point of 40-100° C. and further comprises polyalkylene oxides having MW 50,000-500,000, 1-5 wt %; d) 0.1%-4.8% alkali metal isethionate; e) 2.7%-13.5% water, wherein the sum of water, alkali metal isethionate and water-soluble structurant is 10%-60%, wherein based on the total amount of water, alkali metal isethionate and said water-soluble structurant, • water is present 4-27%, • alkali metal isethionate is present less than 8%, • water-soluble structurant is present 68-90%. Use of the composition for eliminating efflorescence.