ASA Emulsion Particle Size Control via Dilution
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Solution Overview
Problem
The existing process for manufacturing an emulsion of alkenyl succinic anhydride (ASA) in an aqueous solution of cationic starchy material results in unstable particle size distribution over time, deviating from the optimal range of 1 µm to 1.5 µm, which is crucial for effective hydrophobization and bonding properties in paper production.
Innovation Solution
The process involves producing an aqueous solution of cationic starchy material with a dry matter content between 7% and 12%, mixing ASA with it to achieve a dry weight ratio of less than 1, emulsifying in a single pass without recirculation, and diluting the emulsion by a factor of 1.5 to 3.5 to stabilize the particle size.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If the emulsion is manufactured without temperature increase, then hydrolysis of ASA is avoided, but the particle size distribution becomes unstable over time
Solution Approach 1:
The patent changes the concentration parameter by diluting the emulsion to specific ranges (0.5-5% cationic starch, 0.05-0.5% ASA) to stabilize particle size distribution. This parameter adjustment prevents particle aggregation while maintaining emulsion stability during storage and paper machine operations.
2Reliability
If coarse particles are present in the emulsion, then hydrophobization properties are improved, but clogging of paper machine materials and steam entrainment occur
Solution Approach 1:
The patent optimizes the particle size parameter by controlling emulsion concentration and composition to achieve a narrow size distribution centered around 1-2 µm. This parameter control ensures particles are fine enough to avoid clogging and steam entrainment while maintaining sufficient hydrophobization effectiveness.
3Object-generated harmful factors
If fine particles are used in the emulsion, then clogging is prevented, but particles pass through the fibrous mat and are lost in process water
Solution Approach 1:
The patent identifies and applies an optimal particle size range (1-2 µm average diameter) that balances two opposing requirements: fine enough to prevent clogging of machinery, yet coarse enough to be retained by the fibrous mat during paper formation. This optimal parameter range maximizes particle utilization while preventing both clogging and loss.
4Ease of manufacture
If the emulsion particle size is not centered on 1 µm to 1.5 µm, then manufacturing is easier, but bonding effectiveness and hydrophobic properties are reduced
Solution Approach 1:
The patent establishes specific parameter ranges for emulsion concentration (0.5-5% cationic starch, 0.05-0.5% ASA) that naturally produce the desired particle size distribution (1-2 µm average) through the emulsification process. These parameter specifications make the precision particle size control achievable through straightforward manufacturing adjustments.
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
This approach ensures a stable particle size distribution of the emulsion over extended periods, maintaining optimal hydrophobization properties and preventing clogging issues, while avoiding the risks of hydrolysis and particle loss during paper machine shutdowns.
Implementation Method 1
the function of such compositions is to avoid the coalescence of the ASA particles by positive ionization of the surface of the particles
Implementation Method 2
this allows good contact between the ASA and the cellulose fibers. The emulsion in question is an emulsion of ASA in an aqueous solution of cationic starchy material
Data Source
AI summary
The present invention relates to a method for producing an emulsion of alkenyl succinic anhydride (ASA) in an aqueous solution of cationic amylaceous material; this process does not implement a loop for recirculating the product at the level of the emulsifying unit, and performs a dilution of the emulsion once the latter has been produced; a product which has a particle size that is simultaneously fine, monodisperse and stable over time is achieved. An effective process which is simple to implement, in particular on a paper production site, for providing an emulsion which may be stored during the periods when the paper machine is stopped for cleaning or maintenance operations, is thus provided.