Amine-Based Sizing Enhancer for ASA Emulsion Stability
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Solution Overview
Problem
Conventional methods for sizing paper using alkenyl succinic anhydride (ASA) face challenges with shelf life, emulsion stability, and equipment usage, necessitating improvements in sizing performance and efficiency in paper production processes.
Innovation Solution
Combining emulsified ASA with an amine-based chemistry, specifically a copolymer of diallylamine (DAA) and acrylamide (AcAm), added separately or contemporaneously at the wet-end of the papermaking process, enhances sizing performance and strength properties of paper/board.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If ASA is emulsified before addition to the papermaking process, then uniform suspension and contact with cellulosic fibers is achieved, but emulsion stability and shelf life deteriorate
Solution Approach 1:
The patent uses cationic emulsifiers (such as cationic starch or synthetic polymers) as intermediary substances to stabilize the ASA emulsion. These emulsifiers act as mediators between the hydrophobic ASA and hydrophilic water, creating a stable oil-in-water emulsion that maintains uniform suspension while preventing premature separation, thereby resolving the contradiction between uniform suspension and emulsion stability
Solution Approach 2:
The patent modifies the chemical parameters of the emulsion system by adjusting the charge density, molecular weight, and composition of cationic emulsifiers. By changing these parameters, the emulsion stability is enhanced while maintaining uniform ASA distribution, thus resolving the contradiction between manufacturing precision and reliability
2Reliability
If high level of internal sizing is applied to improve structural stability, then resistance to liquid penetration is enhanced, but paper strength is weakened by rewetting at size press
Solution Approach 1:
The patent introduces cationic emulsifiers as intermediary agents that not only stabilize the ASA emulsion but also modify the interaction between ASA and paper fibers during the sizing process. These intermediaries enable high levels of internal sizing to be achieved while protecting paper strength during subsequent rewetting operations at the size press
3Reliability
If conventional ASA emulsification methods are used, then sizing performance is achieved, but equipment usage and operational complexity increase
Solution Approach 1:
The patent employs self-emulsifying properties of certain cationic polymers that can automatically form stable ASA emulsions under papermaking process conditions without requiring extensive external emulsification equipment or complex operational procedures. This self-service mechanism maintains sizing performance while simplifying equipment usage and operation
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 combination significantly improves the paper's resistance to fluid penetration and maintains strength, outperforming emulsified ASA alone, with optimal dosages of the sizing agent and enhancer achieving enhanced sizing efficiency without affecting particle size distribution.
Implementation Method 1
ASA must be emulsified before it is added to the papermaking process. Emulsification of ASA produces an oil-in-water emulsion and also cationizes ASA emulsion droplets.
Implementation Method 2
Common cationic emulsifiers for ASA include derivitized starches and synthetic acrylamide-based polymers. Cationizing the ASA droplets helps to promote emulsion stability and aids in ASA retention.
Implementation Method 3
ASA is an internal sizing agent, which is commonly used to treat fibers in the papermaking process, making them more hydrophobic.
Implementation Method 4
Combining the amine-based chemistry with the sizing emulsion also has the ability to enhance strength properties of the paper/board.
Data Source
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AI summary
The disclosure relates to methods and compositions for enhancing the performance of a sizing agent in a papermaking process using a sizing agent enhancer. The sizing agent can be emulsified with an emulsifier and the sizing enhancer can be a polymer including at least one primary or secondary amine containing monomer. The sizing agent can be emulsified with the emulsifier and thereafter added to a fiber furnish of a papermaking process. The combination of the emulsified sizing agent and the sizing enhancer improves the sizing.