Wax-Encapsulated Metal Oxide Opacifiers for Stable Rinse-Off Compositions
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Solution Overview
Problem
Existing opacifiers in aqueous personal care rinse off compositions face issues with stability, compatibility, and water content, particularly when used in concentrated detergents or unit dose packets, and do not perform as well as styrene acrylic copolymer-based opacifiers.
Innovation Solution
Incorporation of composite opacifier particles, where metal oxide particles like zinc oxide or titanium oxide are partially or completely encapsulated by a wax, with specific size and melting point ranges, to enhance stability and sustainability in aqueous personal care compositions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional styrene acrylic copolymer-based opacifiers are used, then good opacification performance is achieved, but sustainability and environmental compatibility are compromised
Solution Approach 1:
The patent changes the material composition parameters by replacing styrene acrylic copolymer with natural wax and metal oxide particles. The wax is selected from natural sources (carnauba, candelilla, bayberry, castor, coco butter, esparto, laurel, japan, jojoba, ouricury, rice bran, soy, shea butter, sunflower, tallow tree) and metal oxides are used in specific concentrations (1-50 wt% of total opacifier). This parameter change maintains opacification performance while improving environmental compatibility and sustainability.
Solution Approach 2:
The patent creates a composite opacifier system combining natural wax and metal oxide particles (zinc oxide, titanium oxide). The composite structure consists of metal oxide particles partially or completely encapsulated by wax, with specific size ranges (175-275 nm for metal oxide, 300-500 nm for composite). This composite approach achieves both good opacification performance and enhanced environmental compatibility.
2Shape
If opacifiers are used to improve aesthetics, then uniform opaque appearance is achieved, but stability and compatibility with other formulation materials deteriorate
Solution Approach 1:
The natural wax acts as an intermediary substance that bridges the metal oxide particles and the aqueous formulation. The wax coating on metal oxide particles provides compatibility with other formulation materials while maintaining the opacifying function. This intermediary approach ensures both appearance uniformity and formulation stability.
Solution Approach 2:
The patent optimizes particle size parameters (metal oxide: 175-275 nm, composite: 300-500 nm) and wax melting point (45-110°C) to achieve stable dispersion in the formulation. These parameter changes ensure the opacifier remains stable and compatible with other formulation materials while providing uniform opaque appearance.
3Quantity of substance
If opacifiers are used in concentrated detergents, then product concentration is improved, but water content and compatibility issues worsen
Solution Approach 1:
The patent changes the opacifier composition to wax-based metal oxide composites with specific particle sizes (175-275 nm metal oxide, 300-500 nm composite). This parameter change allows effective opacification at lower water contents, enabling use in concentrated detergent formulations while maintaining compatibility and performance.
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 composite opacifier particles provide stable opacification comparable to conventional styrene acrylic copolymers while reducing water content, improving the overall sustainability of the compositions.
Implementation Method 1
composite opacifier particles comprise metal oxide particles that are partially or completely encapsulated by a wax
Implementation Method 2
Opacifiers are materials that make a liquid system opaque... transforming the liquid from clear or translucent to opaque
Data Source
AI summary
An aqueous personal care rinse off composition is provided, comprising: a dermatologically acceptable aqueous vehicle; a dermatologically acceptable cleaning surfactant; and a plurality of composite opacifier particles, wherein the composite opacifier particles comprise metal oxide particles that are partially or completely encapsulated by a wax; wherein the metal oxide particles are selected from the group consisting of zinc oxide, titanium oxide and mixtures thereof; wherein the metal oxide particles have a z average particle size of >100 nm as measured by dynamic light scattering; wherein the wax has a melting point temperature of 50 to 110 °C; and wherein the composite opacifier particles have a z average particle size of >100 nm to 2,000 nm as measured by dynamic light scattering.