Aqueous Polymer Dispersion Viscosity Reduction
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Solution Overview
Problem
Existing aqueous anionic polymer dispersions require high amounts of water-soluble salts for effective and stable polymer particle formation, leading to high viscosity and increased transportation costs, and often use low molecular weight anionic co-stabilizers that interfere with cationic additives in papermaking, necessitating a more efficient and cost-effective production process with improved drainage and retention performance.
Innovation Solution
An aqueous polymer dispersion comprising anionic water-soluble dispersion polymer, polymerized from a monomer mixture including anionic monomers, acrylamide, and a second non-ionic vinyl monomer, with a water-soluble salt present at least 2.0% by weight, produced under free radical conditions, which reduces salt requirements, viscosity, and eliminates the need for low molecular weight co-stabilizers, resulting in a more efficient and cost-effective process with enhanced drainage and retention performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If high amounts of water-soluble salts are used to obtain effective and stable polymer particle formation, then polymer particle stability is improved, but viscosity increases and transportation costs increase
Solution Approach 1:
A non-ionic vinyl monomer is introduced as an intermediary component in the polymer composition. This non-ionic monomer acts as a mediator that reduces the viscosity of the polymer dispersion while maintaining polymer particle stability, thereby resolving the contradiction between particle stability and ease of manufacture/transportation
Solution Approach 2:
The invention changes the chemical composition parameters of the polymer by incorporating a non-ionic vinyl monomer alongside anionic monomers. This parameter change modifies the rheological properties of the dispersion, reducing viscosity while preserving colloidal stability through the unique properties of non-ionic polymer segments
2Reliability
If low molecular weight anionic co-stabilizers are used to stabilize polymer particles, then polymer particle formation is improved, but cationic demand of cellulosic suspensions increases and performance of cationic additives deteriorates
Solution Approach 1:
The invention extracts or eliminates low molecular weight anionic co-stabilizers from the system. By removing these harmful low molecular weight components and replacing them with a non-ionic vinyl monomer-based stabilization system, the patent prevents interference with cationic additives while maintaining polymer particle formation effectiveness
Solution Approach 2:
The invention replaces persistent low molecular weight anionic co-stabilizers with a different chemical approach using non-ionic monomers that do not create long-term harmful effects. This substitution eliminates the ongoing problem of cationic demand increase in papermaking processes
3Quantity of substance
If high dispersion polymer content is achieved, then effectiveness as retention and drainage aid is improved, but difficulty of obtaining such dispersions increases
Solution Approach 1:
The invention changes the compositional parameters by incorporating non-ionic vinyl monomer, which modifies the phase behavior and solubility characteristics of the polymer system. This parameter change enables the formation of high polymer content dispersions that would otherwise be difficult to obtain, reducing manufacturing difficulty while increasing polymer concentration
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 solution achieves stable, low-viscosity polymer dispersions with higher polymer contents, reducing salt usage and viscosity peaks, enabling improved drainage and retention performance in papermaking, allowing for increased paper machine speed and lower additive dosages, thus simplifying production and providing economic benefits.
Implementation Method 1
produced under free radical conditions, which reduces salt requirements, viscosity, and eliminates the need for low molecular weight co-stabilizers
Data Source
AI summary
The invention relates to an aqueous polymer dispersion comprising an anionic water-soluble dispersion polymer comprising in polymerized form a monomer mixture comprising (i) one or more anionic monomers, (ii) a first non-ionic vinyl monomer which is acrylamide, and (iii) at least one second non-ionic vinyl monomer; a water-soluble salt and a stabilizer, wherein the water soluble salt is present in an amount of at least 2.0% by weight, based on the total weight of the dispersion. The invention further relates to a process for producing the aqueous polymer dispersion, use of the aqueous polymer dispersion as a flocculating agent in papermaking or for water purification, and a process for producing paper which comprises adding one or more drainage and retention aids comprising the aqueous polymer dispersion to an aqueous suspension containing cellulosic fibers and then dewatering the obtained suspension.