Emulsion Polymerization Surfactant Mixture Prevents Gel Phase
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Solution Overview
Problem
Emulsion polymerization processes often encounter issues with gel phase formation when surfactant systems are diluted with water, leading to solidified particles that hinder polymerization reactions, making it difficult to perform smoothly.
Innovation Solution
A surfactant mixture comprising alkoxylation products of specific alkanols with controlled alkylene oxide units and branching, used in combination with vinyl aromatic compounds, ethylenically unsaturated carboxylic acids, and α-olefins, which prevents gel phase formation and allows for smooth polymerization.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional surfactant systems are used in emulsion polymerization, then the polymerization reaction can proceed, but gel phase formation occurs when surfactant is diluted with water, leading to solidified particles that hinder the reaction
Solution Approach 1:
The patent changes the chemical parameters of the surfactant system by using specific alkoxylation products with controlled alkylene oxide unit counts (35-55) and specific alcohol chain lengths (C6-C19). This parameter optimization prevents gel phase formation while maintaining polymerization reliability. The surfactant mixture comprises: (A) alkoxylation product of C6-C12 alcohol with 35-55 alkylene oxide units, (B) alkoxylation product of C13-C19 alcohol with 35-55 alkylene oxide units, or (C) alkoxylation product of linear C12-C22 alcohol with 35-55 alkylene oxide units.
2Quantity of substance
If surfactant system is diluted with water to achieve proper concentration, then polymerization can be performed, but gel phases form and solidify particles
Solution Approach 1:
The patent optimizes surfactant concentration and composition parameters by using alkoxylation products with specific OH values (35-55) and controlled molecular weights. This allows the surfactant system to remain stable upon water dilution without forming gel phases, achieving both proper concentration and compositional stability.
Solution Approach 2:
The patent creates a composite surfactant system combining multiple alkoxylation products with different alcohol chain lengths (C6-C19) but matched alkylene oxide unit counts. This composite approach provides synergistic effects that prevent gel phase formation while maintaining stability upon dilution.
3Productivity
If gel phases are formed and re-liquefied to continue polymerization, then reaction can proceed, but heat and time are required which complicates the process
Solution Approach 1:
The patent applies preliminary anti-action by selecting surfactant formulations that inherently resist gel phase formation from the outset. By using alkoxylation products with optimized parameters (35-55 alkylene oxide units, specific alcohol chain lengths), the system prevents gel phase formation before it can occur, eliminating the need for subsequent re-liquefaction steps and associated energy/time costs.
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 process ensures smooth emulsion polymerization without gel phase issues, resulting in polymers with excellent morphology, small particle size, and low water sensitivity.
Implementation Method 1
When diluting them with water prior to use in the actual polymerization vessel, they tend to build up so-called liquid crystallization phases, commonly referred to as gel phases
Implementation Method 2
using a surfactant mixture comprising (A) an alkoxylation product of at least one alkanol (a), characterized in that alkanol (a) has 6 to 12 carbon atoms per molecule and the average number of alkylene oxide units per molecule in alkoxylation product (A) assumes a value in the range of from 35 to 55
Implementation Method 3
Emulsion polymerization processes are well-known methods for the syntheses of high-molecular weight polymers and copolymers
Data Source
AI summary
Process for polymerizing at least one monomer under emulsion polymerization conditions, characterized in that the (co)monomers are selected from vinyl aromatic compounds, ethylenically unsaturated carboxylic acids with 3 to 10 carbon atoms, C1-C10-alkyl esters of ethylenically unsaturated carboxylic acids with 3 to 10 carbon atoms, 1,3-butadiene, and a-olefins bearing in the range of from 10 to 250 carbon atoms per molecule, in pure form or as mixture with isomers, and using a surfactant mixture comprising (A) an alkoxylation product of at least one alkanol (a), characterized in that alkanol (a) has 6 to 12 carbon atoms per molecule and the average number of alkylene oxide units per molecule in alkoxylation product (A) assumes a value in the range of from 35 to 55, the alkylene oxide units are selected from C2-C10-alkylene oxide units and alkanol (a) has an average degree of branching of at least 1; and (B) an alkoxylation product of at least one alkanol (b), characterized in that alkanol (b) has 13 to 19 carbon atoms per molecule and the average number of alkylene oxide units per molecule in alkoxylation product (B) assumes a value in the range of from 35 to 55, the alkylene oxide units are selected from C2-C10-alkylene oxide units, or (C) an alkoxylation product of at least one linear C12-C22-alkyl alcohol (c), characterized in that the average number of alkylene oxide units per molecule in alkoxylation product (C) assumes a value in the range of from 35 to 55, the alkylene oxide units are selected from C2-C10-alkylene oxide units.