Biodegradable Wash Composition Stable at Low pH

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Solution Overview

Problem

Existing wash compositions fail to provide a mild, stable, and biodegradable solution that maintains skin health by preserving the skin microbiota while avoiding syneresis, discoloration, and malodor, especially when formulated without soaps, sulfates, isethionates, thiols, and synthetic thickeners.

Innovation Solution

A wash composition comprising greater than 50% by weight starch-based biodegradable thickener, with a pH of 4.25 or less, using anionic, amphoteric, or zwitterionic surfactants, and minimal nonionic surfactants, free of synthetic thickeners, to create a stable, mild, and effective cleansing experience.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Stability of the object's composition

If synthetic thickeners like ammonium acryloyldimethyltaurate vinylpyrrolidone copolymer or alkyl acrylate cross polymers are used, then viscosity and lather characteristics are improved, but the composition becomes less biodegradable and less environmentally friendly

Engineering Contradiction:
Improveviscosity stabilityVSAvoidenvironmental harm
Core Design Contradiction:
Stability of the object's compositionVSObject-affected harmful factors

Solution Approach 1:

The patent changes the chemical composition parameters of the thickener from synthetic polymers to natural biodegradable alternatives (starch, cellulose, gum) while maintaining the required viscosity and lather characteristics through optimized formulation and pH control at 4.25 or less

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent uses biodegradable thickeners that naturally decompose in the environment, replacing persistent synthetic polymers with environmentally benign materials that break down into harmless substances, effectively using temporary materials that serve their function then degrade

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

2Object-affected harmful factors

If the pH is lowered to 4.25 or less to preserve skin microbiota health, then skin health is improved, but the composition becomes less stable and more prone to syneresis and discoloration

Engineering Contradiction:
Improveskin microbiota harmVSAvoidcomposition stability
Core Design Contradiction:
Object-affected harmful factorsVSStability of the object's composition

Solution Approach 1:

The patent optimizes multiple parameters simultaneously: pH (4.25 or less), thickener composition (starch, cellulose, gum in specific ratios), and surfactant selection to achieve both the desired acidic pH for skin health and compositional stability preventing syneresis and discoloration

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent uses a composite thickener system combining multiple biodegradable materials (starch, cellulose, and gum) that work synergistically to maintain stability at low pH, where each component contributes to overall formulation stability and prevents the adverse effects of acidity

Inventive Principle:
Principle #40Composite materials

3Object-affected harmful factors

If soaps, sulfates, isethionates, and thiols are eliminated to create a milder formulation, then skin mildness is improved, but lather quality and cleansing effectiveness deteriorate

Engineering Contradiction:
Improveskin irritationVSAvoidlather quality
Core Design Contradiction:
Object-affected harmful factorsVSObject-generated harmful factors

Solution Approach 1:

The patent changes the surfactant composition parameters by selecting specific mild surfactants and optimizing their concentrations to achieve effective lather and cleansing without using harsh ingredients like sulfates, soaps, isethionates, or thiols

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent uses biodegradable thickeners as intermediary components that enhance the performance of mild surfactants, providing lather boost and viscosity control without requiring harsh chemicals, acting as mediators between the mild surfactants and the desired lather quality

Inventive Principle:
Principle #24Intermediary (Mediator)

4Object-affected harmful factors

If biodegradable thickeners comprising greater than 50% by weight starch are used, then environmental friendliness is improved, but the composition becomes less stable at elevated temperatures and exhibits syneresis and malodor

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

Solution Approach 1:

The patent creates a composite thickener system combining starch with other biodegradable materials (cellulose and gum) that together provide thermal stability and prevent syneresis and malodor at elevated temperatures, leveraging the complementary properties of each component

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The patent optimizes the formulation parameters including the ratio of starch to other thickeners, pH level, and surfactant composition to enhance the thermal stability of the biodegradable thickener system, preventing degradation and adverse reactions at elevated temperatures

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

The composition maintains skin health by balancing the skin microbiota, provides excellent lather and viscosity, rinses easily, and remains stable without syneresis, discoloration, or malodor even at elevated temperatures.

Implementation Method 1

biodegradable thickener comprising greater than 50% by weight starch based on total weight of thickener

Methodology Applied
Scientific EffectThickening:

Implementation Method 2

surfactant and biodegradable thickener comprising greater than 50% by weight starch

Methodology Applied
Scientific EffectSurfactant action: Surfactant

Implementation Method 3

The wash composition has a pH of 4.25 or less which is ideal for skin microbiota to preserve skin health

Methodology Applied
Scientific EffectAcidification:

Data Source

PatentEP4593790B1Mild wash composition with biodegradable thickener and enhanced microbiota impact
Publication Date: 2026.03.18 UNILEVER IP HLDG BV

AI summary

The invention is directed to a stable composition wash composition. The wash composition comprises a mixture of biodegradable thickeners having starch and cellulose. The wash composition is mild at a pH of 4.2 or under, has a viscosity of 40,000 cps or less, and surprisingly, is free of syneresis, discoloration and malodor, even after being stored at elevated temperatures.