Sulfate-Free Cleansing Composition Viscosity Control
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Solution Overview
Problem
Developing mild, sulfate-free cleansing compositions for hair and skin that maintain desirable rheological properties, such as viscosity and foamability, while using low surfactant concentrations and avoiding the use of thickening polymers or secondary surfactants, which are typically required to achieve these properties.
Innovation Solution
A combination of Alpha Olefin Sulfonate (AOS) as the primary surfactant, along with specific ratios of alkyl betaine, alkyl hydroxy sultaine, or alkyl amphoacetate, and a cationic polymer, with the addition of an inorganic electrolyte, to build viscosity without the need for additional thickening agents, while maintaining mildness and transparency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If sulfate-free surfactants are used together with polymeric thickeners to achieve acceptable viscosity, then the composition can be thickened, but the polymeric thickeners create gelation effects that transform the product from Newtonian to non-Newtonian rheology and limit subsequent viscosity adjustment through simple salts
Solution Approach 1:
The invention extracts and eliminates polymeric thickeners from the formulation, achieving viscosity thickening through simple salts alone. This removes the gelation effect and maintains Newtonian rheology, allowing flexible viscosity adjustment without complex polymer-surfactant interactions.
Solution Approach 2:
The invention changes the thickening mechanism from polymer-based gelation to salt-based ionic strength modulation. By adjusting salt concentration, the composition achieves desired viscosity while maintaining simple Newtonian rheology and enabling subsequent viscosity adjustments through simple salt additions.
2Temperature
If high levels of non-sulfate surfactant are used to build viscosity in sulfate-free systems, then the viscosity increases, but the composition develops liquid crystalline structures that trap surfactant and impair foamability
Solution Approach 1:
The invention changes the approach to viscosity building by using moderate surfactant levels combined with simple salt additions. This prevents liquid crystalline structure formation while achieving adequate viscosity, thereby maintaining good foamability and avoiding surfactant trapping.
Solution Approach 2:
The invention introduces simple salts as intermediary thickening agents that mediate between surfactant molecules to build viscosity without forming complex liquid crystalline structures. This intermediary approach allows viscosity enhancement while preserving foamability and preventing surfactant entrapment.
3Temperature
If high levels of non-sulfate surfactant are used to achieve desired viscosity, then the viscosity is sufficient, but the composition develops turbid or cloudy appearance due to liquid crystalline structures
Solution Approach 1:
The invention changes the formulation parameters by using moderate surfactant concentrations combined with simple salt thickening. This prevents liquid crystalline domain formation that causes turbidity, thereby maintaining composition translucency while achieving adequate viscosity.
4Object-affected harmful factors
If low surfactant concentrations are used in sulfate-free compositions, then the composition is milder, but it becomes difficult to build viscosity and achieve desirable rheological properties
Solution Approach 1:
The invention introduces simple salts as intermediary thickening agents that enable viscosity building in low-surfactant formulations. This intermediary approach allows mild, low-surfactant compositions to achieve desirable rheological properties without requiring high surfactant concentrations or polymeric thickeners.
Solution Approach 2:
The invention changes the formulation strategy by combining low surfactant concentrations with optimized simple salt additions. This parameter adjustment enables viscosity building in mild formulations, achieving desirable rheological properties without compromising mildness or requiring complex thickening systems.
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 solution achieves good foamability, cleaning efficiency, and desirable rheological characteristics, including increased viscosity at low surfactant concentrations, while ensuring the composition remains mild and transparent, thus addressing the challenges of formulating sulfate-free cleansing products.
Implementation Method 1
a cationic polymer, with the addition of an inorganic electrolyte, to build viscosity
Implementation Method 2
the addition of an inorganic electrolyte, to build viscosity without the need for additional thickening agents
Implementation Method 3
A sufficient level of surfactant is ordinarily needed for surfactant molecules to be able to assemble into micelles, and for the micelles to aggregate to build structure
Data Source
AI summary
A sulphate free cleansing composition for hair, scalp or skin comprising, in an aqueous continuous phase: a total amount of anionic surfactant, amphoteric surfactant and zwitterionic surfactant consisting of: (i) from 3 wt % to 13 wt %, by weight of the total composition at 100 % activity, of an alpha olefin sulfonate anionic surfactant of general formula (I): R1-CH=CH-CH2-SO3-M+ (I) in which R1 is selected from linear or branched alkyl groups having from 11 to 13 carbon atoms and mixtures thereof; and M is a solubilizing cation; (ii) from 1 to 6%, by weight of an amphoteric or zwitterionic surfactant, selected from an alkyl betaine of general formula (II) R2-N+(CH3)2-CH2-COO- M+ (II) wherein R2 = C12 (Lauryl) or Coco derived; an alkyl hydroxy sultaine of general formula (III), R3-N+(CH3)2-CH2-CH(0H)-CH2-S03- M+ (III) wherein R3 = C12 (Lauryl) or Coco derived; an alkyl aminopropyl hydroxy sultaine of general formula (IV), R4-C0-NH-(CH2)3-N+(CH3)2-CH2-CH(0H)-CH2-S03- M+ (IV) wherein R4 = C12 (Lauryl) or Coco derived; an alkyl amphoacetate of general formula (V), R5-C0-NH-(CH2)2-N(CH2-CH2-0H)(CH2-C00- M+) (V) wherein R5 = C12 (Lauryl) or Coco derived; and mixtures thereof; (iii) from 0.05 wt % to 0.5 wt % of a cationic polymer; (iv) an inorganic electrolyte; and (iv) water; in which the weight ratio of (i) to (ii) ranges from 1 :1 to 6:1 and the pH of the composition is from 3 to 6.5.