Microfibrous Cellulose in Cationic Surfactant Systems
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Solution Overview
Problem
Cationic surfactant-based products face challenges in thickening and suspension due to incompatibility with conventional anionic thickeners, and existing cationic thickeners are costly or limited in pH compatibility and suspension properties.
Innovation Solution
Microfibrous cellulose, either bacterially derived or mechanically altered, is used to provide suspension and viscosity in cationic surfactant systems, maintaining stability across a wide range of pH and surfactant concentrations without precipitation, and can be combined with co-agents like cationic guar or HEC for enhanced performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If conventional anionic thickeners (xanthan gum, CMC, carrageenan, polyacrylates) are used in cationic surfactant systems, then thickening is achieved, but precipitation of cationic surfactant and thickener occurs or efficacy is reduced
Solution Approach 1:
The patent introduces non-ionic thickeners (hydroxyethylcellulose, hydroxypropylmethylcellulose, scleroglucan, microfibrous cellulose) as intermediary substances that do not interact electrostatically with cationic surfactants. These non-ionic thickeners serve as mediators that provide thickening without causing precipitation, resolving the incompatibility between anionic thickeners and cationic surfactants through neutral interaction mechanisms.
Solution Approach 2:
The patent changes the charge parameter of the thickener from anionic to non-ionic or cationic, transforming the interaction mechanism from electrostatic attraction (causing precipitation) to neutral or synergistic interaction. This parameter change enables stable formulation by eliminating the harmful electrostatic interaction while maintaining thickening functionality.
2Strength
If non-ionic thickeners (HEC, HPMC) are used in cationic systems, then viscosity is provided, but suspension properties are minimal
Solution Approach 1:
The patent combines non-ionic thickeners with cationic surfactants in composite formulations where the cationic surfactant network enhances the suspension capability of the non-ionic thickener. This composite approach leverages the viscosity-providing capability of non-ionic thickeners while the cationic surfactant component provides suspension stability through electrostatic repulsion and network formation.
Solution Approach 2:
The patent seeks a thickener that performs multiple functions: providing viscosity, enabling suspension, and maintaining compatibility with cationic surfactants. The invention identifies non-ionic and cationic cellulose derivatives that can fulfill this multi-functionality, particularly through their ability to form stable networks and interact favorably with cationic surfactant molecules.
3Strength
If cationic thickeners (polyquaternium 10, cationic guar) are used in cationic systems, then thickening is achieved, but suspension properties are not provided
Solution Approach 1:
The patent uses non-ionic cellulose derivatives as intermediary substances that bridge the gap between thickening and suspension functions. These non-ionic thickeners do not compete electrostatically with cationic surfactants, allowing them to provide both viscosity and suspension stability through their unique molecular structure and network-forming capability.
Solution Approach 2:
The patent changes the functional parameters of the thickener by selecting cellulose derivatives with specific molecular weights, degrees of substitution, and viscosities that optimize both thickening and suspension properties. By adjusting these parameters, the formulation achieves superior performance in both aspects simultaneously.
4Reliability
If scleroglucan is used to provide suspension in cationic systems, then good suspension is achieved, but cost-in-use is prohibitive
Solution Approach 1:
The patent substitutes expensive scleroglucan with more cost-effective non-ionic and cationic cellulose derivatives that achieve comparable or superior suspension properties. These alternative thickeners (hydroxyethylcellulose, hydroxypropylmethylcellulose, microfibrous cellulose) provide the necessary suspension functionality at lower costs, making the formulation economically viable.
Solution Approach 2:
The patent optimizes the parameters of alternative thickeners (concentration levels, molecular weights, viscosities) to achieve cost-effectiveness without sacrificing performance. By carefully adjusting these parameters, the formulation achieves good suspension properties using economical ingredients rather than expensive specialty thickeners.
5Strength
If polyacrylates are used to thicken cationic systems, then thickening is effective, but pH limits and narrow compatibility ranges are imposed
Solution Approach 1:
The patent changes the chemical composition parameter from polyacrylate to cellulose derivative, fundamentally altering the pH and compatibility characteristics. Cellulose derivatives, particularly non-ionic and cationic types, exhibit broader pH stability and wider compatibility ranges with cationic surfactants, removing the restrictive parameters imposed by polyacrylates.
Solution Approach 2:
The patent selects cellulose derivatives that provide universal compatibility across different pH ranges and surfactant concentrations. These non-ionic and cationic cellulose derivatives serve as universal thickeners that work effectively in diverse formulation conditions, unlike polyacrylates with their narrow compatibility windows.
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
Microfibrous cellulose effectively suspends particulates in cationic surfactant systems, ensuring transparent solutions and stable suspension of abrasive, aesthetic, and active ingredients, with improved cost-effectiveness and compatibility, as demonstrated in various personal care and industrial applications.
Implementation Method 1
Microfibrous cellulose is unique in its ability to function in these systems in part because it is dispersed rather than solubilized, thereby allowing its use in a wide range of pH and cationic surfactant concentrations without concern of precipitating the polymer
Implementation Method 2
The microfibrous cellulose is non-ionic and is therefore unaffected by the cationic surfactants and maintains good suspension in these systems
Data Source
AI summary
Cationic surfactant systems, using microfibrous cellulose to suspend particulates therein, are described. Methods of making these systems are also described.