High Solids Glyoxalated Polyacrylamide Storage Stability
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Solution Overview
Problem
Commercially available glyoxalated polyacrylamide products have short shelf life due to rapid cross-linking when stored in bulk aqueous solutions, requiring dilute concentrations and significant storage and transportation costs, while existing methods to enhance stability either increase costs or compromise wet/dry strength performance.
Innovation Solution
Development of high solids glyoxalated polyacrylamide compositions with at least 25% by weight cationic monomer, formulated into storage-stable aqueous solutions with higher polymer concentrations, which include a balance of acrylamide and cationic monomers to provide good dry and wet strength, and increased de-watering rates without the need for stabilizers or cooling.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If glyoxalated polyacrylamide is stored in bulk aqueous solution, then it provides adequate concentration for use, but it undergoes rapid cross-linking and gelling during storage, shortening shelf life
Solution Approach 1:
The patent changes the chemical structure parameter of the polyacrylamide by incorporating cationic monomer units (at least 25% by weight) that modify the polymer's interaction with glyoxal. This structural modification reduces the rate of cross-linking reactions during storage, enabling high solids formulations (≥10% polymer) to remain stable for extended periods without gelling, thus resolving the contradiction between maintaining adequate concentration and ensuring storage stability
Solution Approach 2:
The invention creates a composite polymer system combining acrylamide units with cationic monomer units (such as dimethyldiallylammonium chloride) in a specific ratio. This composite structure provides both the desired functionality and reduced cross-linking tendency, allowing the formulation to maintain high polymer concentration while achieving improved storage stability and extended shelf life
2Reliability
If dilute concentration (7.5%) is used to extend shelf life, then storage stability improves, but transportation and handling volumes increase significantly
Solution Approach 1:
By modifying the polymer composition to include at least 25% cationic monomer by weight, the patent enables formulations at ≥10% polymer concentration to achieve extended shelf life (≥6 months at 25°C). This parameter change in composition allows concentration increase without the rapid gelling that would otherwise occur, thus reducing transportation volume while maintaining adequate shelf life
Solution Approach 2:
The patent performs preliminary stabilization by incorporating the cationic monomer into the polymer structure before formulation and storage. This preliminary structural modification prevents subsequent cross-linking and gelling during storage and transportation, allowing the product to be formulated and transported at higher concentrations without the need for later stabilization measures or volume reduction
3Ease of manufacture
If cationic monomer content is kept below 5 mole percent, then manufacturing costs are reduced, but wet strength performance is limited
Solution Approach 1:
The patent changes the cationic monomer content parameter to at least 25% by weight (which corresponds to a significant mole percent), optimizing the balance between manufacturing cost and performance. This parameter change provides sufficient cationic charge for good wet strength while maintaining cost-effectiveness, resolving the contradiction between manufacturing cost and wet strength performance
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 high solids glyoxalated polyacrylamide compositions demonstrate improved storage stability and performance, allowing for higher concentrations without gelling, reducing transportation and handling costs, and maintaining comparable strength to commercial 7.5% solutions, while extending shelf life and enabling efficient papermaking processes.
Implementation Method 1
Glyoxalated polyacrylamide (G-PAM) is used in a variety of paper grades to provide paper with dry and temporary wet strength... glyoxalated polyacrylamide increases the initial wet strength of many household tissues... Glyoxalated polyacrylamide generally has been prepared by reacting glyoxal with a cationic polyacrylamide in slightly alkaline aqueous solution
Implementation Method 2
The cationic charge is obtained by copolymerizing acrylamide with a cationic monomer, which is typically dimethyldiallylammonium chloride
Data Source
AI summary
Storage-stable glyoxalated polyacrylamide polymers and high solids aqueous compositions formulated with them are described. These glyoxalated polyacrylamide compositions can be used as additives for papermaking, providing paper with good dry and temporary wet strength, and increasing papermaking de-watering rates.