Organopolysiloxane Emulsion Polymerization Viscosity Control
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Solution Overview
Problem
Existing methods for producing high-viscosity organopolysiloxane emulsions struggle to achieve fine particle sizes and efficiently control octamethylcyclotetrasiloxane content, limiting production efficiency and environmental sustainability.
Innovation Solution
A method involving the use of high molecular weight organopolysiloxanes with silanol groups, nonionic and anionic surfactants in a specific mass ratio, and initial emulsification in a small amount of water, followed by emulsion polymerization at controlled temperatures, to achieve desired viscosity and reduce octamethylcyclotetrasiloxane content.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If direct emulsification of high-viscosity organopolysiloxane is performed, then the process is simple, but the particle size of emulsion particles cannot be reduced below several microns
Solution Approach 1:
The emulsification process is divided into two distinct stages: first emulsification (creating initial emulsion particles) and second emulsification (further reducing particle size). This segmentation allows each stage to be optimized independently, achieving fine particle sizes below 300 nm that would be impossible with direct single-stage emulsification.
2Manufacturing precision
If emulsion polymerization is performed to obtain fine emulsion particles, then particle size can be reduced to 300 nm or less, but the production time becomes excessively long
Solution Approach 1:
The first emulsification step creates a pre-emulsified state with controlled particle size distribution before initiating polymerization. This preliminary action prepares the system for more efficient polymerization, reducing the total time required to achieve fine particle sizes while maintaining production efficiency.
Solution Approach 2:
The patent optimizes multiple parameters including the mass ratio of nonionic to anionic surfactants (1:4 to 4:1), water content (5-50 mass%), and emulsification conditions. These parameter changes enable fine particle size achievement within a practical production time frame of 1-10 hours.
3Manufacturing precision
If conventional emulsion polymerization methods are used, then fine emulsions can be obtained, but the octamethylcyclotetrasiloxane content reaches 40,000 ppm or more
Solution Approach 1:
The patent systematically optimizes composition parameters including surfactant types and ratios, water content, and monomer concentration. These parameter changes suppress octamethylcyclotetrasiloxane generation while maintaining fine particle size achievement, reducing harmful substance content to 3,000 ppm or less.
Solution Approach 2:
The patent introduces specific surfactants as intermediaries that mediate between the hydrophobic organopolysiloxane and hydrophilic water phase. This intermediary action enables controlled emulsification that suppresses unwanted side reactions generating octamethylcyclotetrasiloxane while achieving fine particle sizes.
4Force
If the viscosity of organopolysiloxane in emulsion is adjusted to high values, then the desired product performance is achieved, but the emulsion polymerization time increases
Solution Approach 1:
The first emulsification step creates a pre-emulsified system with optimized particle distribution before polymerization begins. This preliminary preparation enables faster polymerization kinetics, allowing high viscosity (1,000-1,000,000 mPa·s) to be achieved within 1-10 hours rather than extended periods.
Solution Approach 2:
The patent optimizes the mass ratio of nonionic to anionic surfactants and water content to control polymerization kinetics. These parameter changes enable efficient polymerization that achieves desired high viscosity values in shorter times while maintaining fine particle size and low harmful substance 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
This method enables the production of organopolysiloxane emulsions with extremely fine particle sizes and high viscosity in a shorter time, while maintaining low octamethylcyclotetrasiloxane levels, enhancing production efficiency and environmental sustainability.
Implementation Method 1
using a nonionic surfactant and an anionic surfactant in a mass ratio within a range from 20:80 to 55:45 for the emulsification of the raw material organopolysiloxane
Implementation Method 2
performing emulsion polymerization in an emulsified state using a strong acid or a strong base
Data Source
AI summary
A method for producing an organopolysiloxane emulsion composition, which enables the organopolysiloxane to be formed with a high viscosity in a short period of time, and suppresses the amount of octamethylcyclotetrasiloxane (D4) to not more than 3,000 ppm. Specifically, a method for producing an organopolysiloxane emulsion which includes emulsifying a mixture containing 100 parts by mass of an organopolysiloxane represented by formula: HO(R12SiO)nH (wherein R1 represents a hydrogen atom or a hydrocarbon group) and having a D4 content of not more than 1,000 ppm, a nonionic surfactant, an anionic surfactant, and 1 to 10 parts by mass of water, and subjecting the obtained emulsion composition to emulsion polymerization at a temperature of less than 40°C, thus preparing an emulsion composition in which the viscosity of the organopolysiloxane generated in a polymerization time of not more than 15 hours is 300,000 mPa·s or greater, and the amount of D4 contained in the organopolysiloxane is not more than 3,000 ppm.