Glyoxalated Polyacrylamide Production via Turbidity Control
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Solution Overview
Problem
Existing methods for producing dry strength agents for the paper industry face challenges such as high water content, short shelf life, and incomplete conversion of glyoxal, leading to unstable products and inefficient transportation, storage, and use.
Innovation Solution
A batch process is employed where polyacrylamide reacts with ethanedial in a basic medium, with precise control using turbidity measurement, pH adjustment, reaction time, and power consumption of the circulation pump to ensure quantitative conversion of glyoxal, reducing water content and enhancing storage stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the reaction is stopped based on viscosity measurement, then the desired adduct is formed, but a water-insoluble gel is formed if the reaction is not stopped at the precise moment
Solution Approach 1:
The patent changes the measurement parameter from viscosity to turbidity. Turbidity measurement provides a more reliable and easier-to-monitor parameter that clearly indicates the endpoint of the glyoxylation reaction without the risk of forming water-insoluble gels, thus resolving the precision and reliability contradiction
Solution Approach 2:
The patent replaces the viscosity measurement system with a turbidity measurement system. This substitution uses optical properties rather than mechanical/rheological properties to detect the reaction endpoint, providing more reliable and easier control
2Ease of operation
If the product is transported by tanker truck to the end user, then the product is delivered, but enormous quantities of liquid must be transported and storage life is reduced
Solution Approach 1:
The patent extracts and removes excess water from the reaction mixture through controlled evaporation and drying processes. This concentrates the glyoxylated polyacrylamide product, reducing the volume from enormous quantities of liquid to a compact dry or concentrated form, thereby eliminating the need for tanker truck transport and extending storage life
Solution Approach 2:
The patent utilizes phase transition from liquid to solid/dry state through controlled drying. The reaction mixture is transformed from a liquid suspension requiring transport to a dry powder or concentrated form that can be stored indefinitely and applied directly at the paper mill
3Quantity of substance
If the concentration of vinylamide polymer is too high for use, then the product is compact, but it must be diluted before actual use
Solution Approach 1:
The patent creates a dynamic concentration product that can be adjusted during application. The dry or concentrated glyoxylated polyacrylamide is designed to be mixed with water or paper machine liquor at variable ratios, allowing the end user to optimize the concentration for different paper types and production conditions, thus resolving the contradiction between compactness and usability
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 achieves complete conversion of glyoxal, resulting in a dry strength agent with extended storage stability and reduced water content, allowing for immediate use and precise production control.
Implementation Method 1
an aqueous solution of polyacrylamide is mixed with ethanedial (glyoxal) while stirring by means of a circulation pump
Implementation Method 2
the reaction is started by adding a base, in particular a strong base, at a pH value greater than 8
Implementation Method 3
the reaction is stopped by adding an acid while stirring or circulating
Implementation Method 4
polyacrylamide reacts with ethanedial in a basic medium
Implementation Method 5
an aqueous solution of polyacrylamide is mixed with ethanedial (glyoxal) while stirring by means of a circulation pump, the reaction is started by adding a base
Data Source
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AI summary
The invention relates to a method for producing a dry strengthening agent, particularly glyoxalated polyacrylamide, in which ethanedial (glyoxal) is added to an aqueous solution of polyacrylamide while being agitated with a circulation pump. In said method, the reaction is started by adding a base, particularly a strong base at a basic pH value, particularly a pH value of higher than 8, and is left to react while being agitated and/or circulated, and once a predetermined reaction time has passed, the reaction is stopped by adding an acid while being agitated and/or circulated. The method is carried out as a discontinuous method in which a quantitative reaction of the ethanedial with a surplus amount of polyacrylamide in an aqueous basic medium is open-loop and/or closed-loop controlled on the basis of at least one and preferably at least two of the following factors: a) turbidimetric analysis, b) pH value adjustment depending on the temperature, c) pH value adjustment depending on the reaction time, d) drop in pH value or e) current consumption of the circulation pump.