Two-Stage Emulsion Polymerization Prevents Coagulate
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Solution Overview
Problem
Conventional emulsion polymerization processes for preparing polymers with high carboxyl groups often result in the formation of coagulate or wall deposits, leading to filtration issues and adverse effects on the processing of cosmetic and other preparations.
Innovation Solution
A two-stage emulsion polymerization process is employed, where the first stage includes heating a mixture of monomers and water with a surface-active agent, followed by the addition of a polymerization initiator, and a second stage where additional monomers are added, allowing for controlled polymerization and minimizing coagulate formation by maintaining specific ratios of monomers and using a thermally activatable initiator.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If conventional emulsion polymerization is used to prepare polymers with high carboxyl groups, then the polymer content can be achieved, but coagulate or wall deposit formation occurs hindering the preparation process
Solution Approach 1:
The patent applies segmentation by dividing the polymerization process into two distinct stages: a first polymerization stage and a second polymerization stage. This segmentation allows control over monomer conversion and coagulate formation at different phases of the process, preventing the harmful effects of single-stage polymerization while maintaining high polymer content.
Solution Approach 2:
The patent implements preliminary action by conducting the first polymerization stage before the second stage. During this first stage, specific monomers are polymerized under controlled conditions to establish a foundation that prevents coagulate formation in the subsequent second stage, thereby preparing the system in advance to avoid harmful effects.
2Productivity
If conventional emulsion polymerization is used, then polymer production can proceed, but fine coagulate formation blocks filters and cannot be separated by conventional filtration
Solution Approach 1:
By segmenting the polymerization into two stages with controlled monomer addition and conversion rates, the process prevents the formation of fine coagulate that would otherwise be difficult to filter. The segmented approach ensures polymers remain in a dispersible state throughout production, maintaining both productivity and ease of manufacture.
Solution Approach 2:
The patent applies parameter changes by controlling the progression of monomer conversion through the two-stage process. By adjusting parameters such as monomer feed rates, temperature, and stage timing, the system maintains optimal conditions that prevent coagulate formation, ensuring both high productivity and easy filtration.
3Reliability
If high carboxyl group content is achieved through conventional polymerization, then polymer functionality is improved, but wall deposit formation occurs within the reaction space
Solution Approach 1:
The first polymerization stage serves as a preliminary action that establishes controlled polymerization conditions before the second stage. This preliminary phase prevents wall deposit formation by controlling monomer conversion and polymer growth rates, allowing high carboxyl group content to be achieved without the harmful wall deposits that would compromise reliability.
Solution Approach 2:
The patent employs parameter changes through the two-stage process, adjusting monomer composition, conversion rates, and reaction conditions between stages. These parameter changes enable the system to achieve high polymer functionality with carboxyl groups while preventing wall deposit formation that would otherwise occur in conventional single-stage polymerization.
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 prevents coagulate formation, enabling clear, filterable polymer dispersions that are soluble at pH > 7, suitable for cosmetic and other applications, and allows for the production of clear gels with improved rheology-modifying properties.
Implementation Method 1
a thermally activatable initiator
Implementation Method 2
by emulsion polymerization... a free-radical polymerization is initiated
Implementation Method 3
heating a mixture of monomers and water with a surface-active agent
Implementation Method 4
emulsion polymerization of unsaturated monomers... preparation of polymers comprising carboxyl groups by emulsion polymerization
Data Source
Figure 1
AI summary
The present invention relates to a process for the preparation of polymers comprising carboxyl groups by emulsion polymerization and the use of the polymers obtainable by this process, for example as thickeners. Moreover, the invention relates to thickener dispersions obtainable by the process and to the use thereof for modifying the rheology of paper coating slips, textile printing pastes, drugs, cosmetic preparations, detergents, cleansing compositions or foods.