HASE Polymer Structuring for Stable Insoluble Suspension

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Solution Overview

Problem

Personal cleansing compositions that are unstructured struggle to stably suspend insoluble materials like hydrophobic oils or waxes and particulate exfoliants, leading to storage stability issues and high production costs, with existing solutions either having undesirable rheology or requiring expensive synthetic polymers and complex surfactant blends.

Innovation Solution

A personal cleansing composition combining water, anionic surfactants, amine oxide surfactants, and a hydrophobically modified alkali-swellable acrylic emulsion (HASE) polymer, which creates a structured network for stable suspension of insoluble substances without the need for high levels of expensive polymers or complex surfactant blends, allowing for flexible oil incorporation and clear gel formation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Stability of the object's composition

If unstructured personal cleansing compositions are used, then the composition is simple to formulate, but it cannot stably suspend insoluble materials leading to poor storage stability

Engineering Contradiction:
Improvestorage stabilityVSAvoidformulation complexity
Core Design Contradiction:
Stability of the object's compositionVSDevice complexity

Solution Approach 1:

The patent introduces a HASE polymer as an intermediary structuring agent that mediates between the aqueous phase and insoluble benefit agents. This polymer creates a structured network that suspends insoluble materials without requiring complex surfactant blends or multiple natural gums, thus improving storage stability while maintaining formulation simplicity.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent changes the rheological parameters of the composition by incorporating HASE polymer, which provides shear-thinning behavior and yield stress. This parameter change enables the composition to maintain stability at rest (high viscosity) while flowing easily during use (low viscosity under shear), resolving the contradiction between stability and simplicity.

Inventive Principle:
Principle #35Parameter changes

2Stability of the object's composition

If natural gums are used as structurants, then the composition can suspend insoluble materials, but the rheology becomes undesirable appearing thick at rest but runny in use

Engineering Contradiction:
Improvesuspension stabilityVSAvoidin-use flow properties
Core Design Contradiction:
Stability of the object's compositionVSEase of operation

Solution Approach 1:

The patent employs HASE polymer to change the rheological parameters of the composition, specifically achieving shear-thinning behavior. The composition maintains high viscosity at rest for stable suspension but exhibits low viscosity under shear stress during dispensing and application, thus improving both suspension stability and in-use flow properties simultaneously.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent introduces dynamic rheological properties through HASE polymer, making the viscosity of the composition variable based on applied stress. The structure is dynamic rather than static, adapting its flow properties from thick at rest to runny in use, which resolves the contradiction between suspension stability and ease of operation.

Inventive Principle:
Principle #15Dynamics

3Ease of operation

If synthetic polymers like carbomers are used to improve flow behavior, then the rheology improves, but the cost increases due to high inclusion levels required

Engineering Contradiction:
Improveflow behaviorVSAvoidpolymer inclusion level
Core Design Contradiction:
Ease of operationVSQuantity of substance

Solution Approach 1:

The patent changes the chemical structure parameters of the polymer by selecting HASE polymer with specific hydrophobic modifications. This structural parameter change enables effective structuring at lower inclusion levels (0.1-5% w/w) compared to conventional synthetic polymers, thus improving flow behavior while reducing the quantity of polymer required and lowering costs.

Inventive Principle:
Principle #35Parameter changes

4Stability of the object's composition

If structured surfactant systems are used to suspend insoluble materials, then storage stability improves, but the formulation requires precise surfactant combinations and high oil levels increasing cost

Engineering Contradiction:
Improvesuspension stabilityVSAvoidsurfactant system complexity
Core Design Contradiction:
Stability of the object's compositionVSDevice complexity

Solution Approach 1:

The patent extracts the structuring function from the surfactant system and assigns it to the HASE polymer. This separation allows the surfactants to focus on their primary cleansing function while the polymer handles suspension and rheology control, reducing surfactant system complexity and allowing greater formulation flexibility without compromising suspension stability.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The HASE polymer serves multiple functions simultaneously: it acts as a structuring agent, suspending agent, and rheology modifier. This multi-functionality replaces the need for complex surfactant blends and high oil levels required by traditional structured surfactant systems, reducing formulation complexity and cost while maintaining suspension stability.

Inventive Principle:
Principle #6Universality (Multi-functionality)

5Ease of operation

If high levels of oil are incorporated to achieve desired texture in structured surfactant systems, then the product texture improves, but the formulation cost significantly increases

Engineering Contradiction:
Improveproduct textureVSAvoidoil inclusion level
Core Design Contradiction:
Ease of operationVSQuantity of substance

Solution Approach 1:

The patent changes the rheological parameters of the aqueous phase by incorporating HASE polymer, which provides the desired thick, creamy texture independently of oil content. This parameter change in the continuous phase allows for flexible oil incorporation (0-50%) without prohibitive cost implications, as the polymer provides the structural framework for texture development.

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 achieves stable suspension of insoluble substances, maintains viscosity at rest, and reduces viscosity under shear, providing a cost-effective, easy-to-manufacture, and mild personal cleansing product with improved sensory qualities and shelf life.

Implementation Method 1

structure is built as the critical concentration is exceeded, but in the case of the HASE rheology modifiers, it is by polymer chain entanglement, in conjunction with association of the extended hydrophobic groups on the polymer backbone with each other and other hydrophobic groups in a formulation

Methodology Applied
Scientific EffectHydrophobic interaction: Hydrophobe

Implementation Method 2

structure is built as the critical concentration is exceeded, but in the case of the HASE rheology modifiers, it is by polymer chain entanglement

Methodology Applied
Scientific EffectPolymer chain entanglement:

Implementation Method 3

WO 7,488,707 describes an aqueous structured surfactant system... It is said to exhibit shear-thinning viscosity

Methodology Applied
Scientific EffectShear-thinning: Shear Thinning

Data Source

PatentEP3448353A1Personal cleansing composition
Publication Date: 2019.03.06 PZ CUSSONS INT

AI summary

The present invention relates to personal cleansing compositions in liquid or gel form, which can be used for cleansing the skin and hair and is particularly useful as a body wash, facial wash or hand wash. A key feature of the invention is its highly structured nature arising from interaction of polymeric and surfactant constituents, which is useful for the stable incorporation of insoluble benefit agents such as particulate exfoliants, encapsulates or oils. Furthermore, the present invention is cost effective, offers a high degree of mildness, has desirable in-use properties and is easy to manufacture.