Aminofunctional Silicone Emulsion Process
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Solution Overview
Problem
The challenge in the hair care industry is to reduce the presence of solvents, un-reacted siloxanes, catalyst residues, and cyclic polymerization byproducts in silicone emulsions, particularly cyclosiloxanes, due to their incompatibility with downstream applications and regulatory requirements, which affects emulsion stability.
Innovation Solution
A process involving the use of a halide-free quaternary ammonium surfactant and a neutralizing agent with the same counter-ion, combined with polydialkylsiloxane and aminofunctional organopolysiloxane, to minimize cyclic siloxane generation and enhance chemical stability of aminofunctional silicone emulsions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional emulsion preparation methods are used, then the emulsion can be formed, but the content of cyclosiloxanes (octamethylcyclotetrasiloxanes and decamethylcyclopentasiloxanes) increases, reducing storage stability and violating regulatory requirements
Solution Approach 1:
The patent changes the chemical parameters of the emulsion system by using a specific quaternary ammonium surfactant with a particular counter-ion (methosulfate) and matching it with a neutralizing agent containing the same counter-ion. This parameter matching approach minimizes the generation of cyclosiloxanes during storage while maintaining emulsion stability, thereby resolving the contradiction between storage stability and cyclosiloxane content.
2Object-generated harmful factors
If a halide-free quaternary ammonium surfactant is used, then cyclosiloxane generation is reduced, but complete chemical stability is not achieved
Solution Approach 1:
The patent achieves complete chemical stability by carefully selecting the neutralizing agent to contain the same counter-ion (methosulfate) as the quaternary ammonium surfactant. This parameter matching prevents re-equilibration and cyclic siloxane generation, fully resolving the chemical stability issue while maintaining reduced cyclosiloxane generation.
3Ease of operation
If neutralizing agents with different counter-ions are used, then the emulsion can be neutralized, but re-equilibration occurs and cyclic siloxanes are generated
Solution Approach 1:
The patent resolves this contradiction by specifying that the neutralizing agent must contain the same counter-ion (methosulfate) as the quaternary ammonium surfactant. This parameter matching allows effective neutralization while preventing re-equilibration and cyclic siloxane generation, thus achieving both ease of operation and harm reduction.
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
This process significantly reduces the content of octamethylcyclotetrasiloxanes and decamethylcyclopentasiloxanes, improving the storage stability and chemical stability of the emulsions, meeting regulatory requirements and ensuring compatibility with cosmetic and personal care applications.
Implementation Method 1
using a neutralizing agent with the same counter-ion as that contained on the quaternary ammonium surfactant improves the chemical stability of the aminofunctional silicone emulsion by further minimizing the generation of cyclic siloxanes upon storage
Data Source
AI summary
A process for preparing an aminofunctional silicone emulsion is disclosed comprising: I) forming a mixture of 100 parts of a polydialkylsiloxane having a viscosity of at least 50,000 mm2/s at 23°C, and 0.1 to 100 parts of an aminofunctional organopolysiloxane, II) admixing to the mixture of step I 0.1 to 50 parts of a halide free quaternary ammonium surfactant, and a sufficient amount of water to form an emulsion, III) optionally, further shear mixing the emulsion; and IV) adding a sufficient amount of an acid of the formula H+ X- to provide the emulsion with a neutral pH, where X is the same counter ion used in the quaternary ammonium surfactant.