Diblock Copolymer Emulsifier for Stable High-Water Silicone Emulsions
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Solution Overview
Problem
Existing emulsifiers, such as polyoxyalkylene fatty acid esters, struggle to maintain stability in water-in-oil emulsions when a large amount of water phase is added, leading to separation of phases and a sticky texture, especially when using silicone oils.
Innovation Solution
A diblock copolymer with a hydrophobic silicone graft copolymer block and a polar copolymer block with specific functional groups is used as an emulsifier, enhancing interactions between the water and oil phases for improved stability and emulsifying capability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If a large amount of water phase component is added to achieve wateriness, then the water content increases, but the stability of the emulsion is impaired and phase separation occurs
Solution Approach 1:
The patent changes the chemical structure parameters of the emulsifier from conventional polyoxyalkylene fatty acid esters to a diblock copolymer with a silicone graft copolymer block and a polar copolymer block. This structural parameter change enables the emulsifier to maintain effective concentration at the oil-water interface even with large amounts of water, preventing phase separation while achieving high water content (70-90 wt%).
Solution Approach 2:
The emulsifier is designed as a composite molecular structure combining two distinct blocks: a hydrophobic silicone graft copolymer block (providing oil phase compatibility) and a hydrophilic polar copolymer block (providing water phase compatibility). This composite structure allows simultaneous effective interaction with both oil and water phases, enabling stable emulsions with high water content without phase separation.
2Stability of the object's composition
If thickeners or gelators are added to achieve stability, then the emulsion stability improves, but the wateriness is lost and sticky texture results
Solution Approach 1:
The patent extracts and eliminates the need for thickeners and gelators from the emulsion formulation by using a specifically designed diblock copolymer emulsifier. The copolymer's dual-block structure provides inherent stability through strong interfacial adsorption, allowing the emulsion to remain stable without additional thickening agents, thus maintaining wateriness and smooth non-sticky texture.
3Adaptability or versatility
If conventional emulsifiers are used with silicone oil, then compatibility with oil phase is achieved, but stability with large water amounts cannot be obtained
Solution Approach 1:
The emulsifier exhibits local quality differentiation through its diblock structure: the silicone graft copolymer block provides local hydrophobic character for strong interaction with silicone oil, while the polar copolymer block provides local hydrophilic character for water phase compatibility. This local quality differentiation within a single molecule enables simultaneous optimization of oil phase compatibility and overall emulsion stability with high water content.
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 diblock copolymer achieves a stable water-in-oil emulsion with high water content without the need for thickeners or gelling agents, maintaining smooth texture and stability over time.
Implementation Method 1
a hydrophobic silicone graft copolymer block
Implementation Method 2
a polar copolymer block having a particular polar group(s) serving as a functional group
Implementation Method 3
the interaction between the polar group(s) and a water phase and the interaction between the silicone moiety and an oil agent will turn into a stronger and more efficient interaction
Data Source
AI summary
Provided are an emulsifier exhibiting a high preservation stability and having an excellent emulsifying capability in a wide range of emulsification compositions; and an emulsion composition containing such emulsifier. The emulsifier is comprised of a diblock copolymer whose main chain is comprised of a silicone graft copolymer block represented by a formula [I] and a polar copolymer block represented by a formula [II], wherein one end structure of the main chain is represented by a formula [III], and the other end structure of the main chain is represented by a formula [IV], the formulae [I] to [IV] being expressed as wherein R1 represents a hydrogen atom or a methyl group; A represents an organopolysiloxane-containing group; n1 satisfies 1≤ n1 ≤50; B represents a polar groupcontaining monovalent hydrocarbon group having 1 to 20 carbon atoms, an amino group or a hydroxyl group; n2 satisfies 1≤ n2≤50; R6 represents an alkyl group having 1 to 4 carbon atoms; each R7 independently represents a hydrogen atom or an alkyl group having 1 to 4 carbon atoms; X represents the group represented by A in the formula [I] or the group represented by B in the formula [II].