Cationic Polymer Dispersion Viscosity Control
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing cationic water-in-water polymer dispersions face issues with uncontrollable viscosity increases during production and storage, leading to rheological problems and reduced effectiveness as flocculation agents, especially under extreme conditions.
Innovation Solution
The development of cationic water-in-water polymer dispersions with a cationic polymer A and polymeric cationic dispersant B, where polymer A is composed of 1-60 wt% cationic monomers and 99-40 wt% nonionic monomers, and dispersant B is synthesized from 30-100 wt% cationic monomers with an average molecular weight of 75,000 to 350,000 g/mol, ensuring stability and low residual monomers, thus avoiding rheological issues and maintaining effective flocculation properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If high amounts of salts are added during polymerisation to control viscosity, then the viscosity of the resulting water-in-water dispersions is reduced, but the dispersions become unacceptable for many intended applications due to high salt content
Solution Approach 1:
The invention changes the chemical composition parameters by using specific cationic monomers (diallyldimethylammonium chloride, dimethylaminopropylamine) and controlling their content (2-60 wt%) to achieve viscosity control without requiring high salt amounts. The molecular weight of the polymeric dispersant is also optimized (180,000-1,500,000) to maintain stability and pourability with minimal salt addition.
Solution Approach 2:
The invention creates a composite system combining polymeric dispersants with specific cationic monomer contents and controlled molecular weights, along with minimal salt amounts (1-10 wt%), to achieve both viscosity control and application suitability. This composite approach allows the dispersion to maintain stability while being acceptable for various applications.
2Stability of the object's composition
If minor deviations in salt content or cationic monomer component occur, then an unexpectedly massive, uncontrollable increase in viscosity may occur, but maintaining strict control increases production complexity
Solution Approach 1:
The invention optimizes the molecular weight parameter of the polymeric dispersant (180,000-1,500,000) and the cationic monomer content (2-60 wt%) to create a system with built-in stability margins. This parameter optimization reduces the system's sensitivity to minor compositional deviations, preventing massive viscosity increases while maintaining production feasibility.
Solution Approach 2:
The invention incorporates minimal amounts of salt (1-10 wt%) beforehand to cushion against viscosity increases that might otherwise occur due to minor compositional variations. This pre-added salt acts as a buffer, preventing uncontrollable viscosity spikes while maintaining dispersion stability and pourability.
3Ease of operation
If water-in-water dispersions are diluted beyond a particular level, then dilution results in an undesirably high increase of the Brookfield viscosity, but insufficient dilution limits usability
Solution Approach 1:
The invention changes the molecular weight parameter of the polymeric dispersant (180,000-1,500,000) to optimize the viscosity-dilution relationship. This parameter change allows the dispersion to be diluted to usable levels while preventing an undesirably high increase in Brookfield viscosity, achieving both dilution flexibility and viscosity control.
4Ease of operation
If polyvalent anionic salt is added in amounts of at least 15 wt% to reduce viscosity peaks during polymerisation, then the viscosity of the resulting water-in-water dispersion is reduced, but the high amount of salt prevents use in all intended applications
Solution Approach 1:
The invention changes the salt content parameter from high amounts (15 wt% and above) to low amounts (1-10 wt%), combined with optimized polymeric dispersant molecular weight (180,000-1,500,000) and cationic monomer content (2-60 wt%). This parameter change achieves viscosity control during polymerisation while maintaining application versatility.
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 resulting polymer dispersions exhibit stable rheological behavior, low viscosity, and high effectiveness as flocculation agents, even under extreme storage conditions, with residual monomer levels below 1000 ppm and viscosity within the desired range, meeting industrial demands for rapidity and effectiveness.
Implementation Method 1
a continuous aqueous phase containing a polymeric cationic dispersant B... stabilizing the dispersed polymer
Implementation Method 2
dispersant B is formed from 30-100 wt% of cationised dialkylaminoalkyl(meth)acrylamides... ensuring stability
Implementation Method 3
subsequent polymerisation thereof... polymer A is formed from a1) 1-60 wt% of cationic monomers... and a2) 99-40 wt% of nonionic monomers
Implementation Method 4
To reduce the viscosity peaks which occur during polymerisation... with addition of free-radical initiators, free-radical polymerisation of the monomer mixture is performed
Data Source
AI summary
The invention relates to water-in-water polymer dispersions containing a polymer A with a cationic monomer fraction of up to 60 wt. % and at least one polymer dispersant B, based on cationised dialkylaminoalkyl (meth)acrylamides with an average molecular weight of between 75,000 and 350,000 g/mol. The invention also relates to a method for producing said dispersions and to the use of the latter.