Molten AKD Metering in Shearing Device for Paper Sizing
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Solution Overview
Problem
Existing methods for preparing sized paper or paperboard using alkyl ketene dimer (AKD) require complex formulations with protective colloids and additives to achieve stable dispersions, complicating the papermaking process.
Innovation Solution
A process involving a cellulosic suspension is formed, with a second stream of suspension flowing through a shearing device where molten AKD is metered in, creating an AKD cellulosic composition that is then incorporated into the first suspension, eliminating the need for formulated dispersions and stabilizers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If AKD is put into an aqueous dispersion with protective colloids and additives, then the dispersion stability is improved, but the formulation complexity increases
Solution Approach 1:
The invention extracts and eliminates the protective colloids and stabilizing additives from the traditional AKD dispersion formulation. By using neat molten AKD directly in the papermaking process without formulating it into a complex aqueous dispersion, the patent achieves effective sizing while dramatically simplifying the formulation and removing the need for multiple chemical additives.
Solution Approach 2:
The invention changes the physical state parameter of AKD from solid (requiring dispersion) to molten liquid (可直接使用). By heating AKD to its melting point and applying it in molten form directly to the papermaking process, the patent eliminates the need for aqueous dispersion and associated stabilizing agents, thereby simplifying the formulation while maintaining effectiveness.
2Stability of the object's composition
If protective colloids are added to stabilize AKD dispersion, then the dispersion stability is improved, but the number of additives increases
Solution Approach 1:
The invention removes protective colloids and other stabilizing additives from the formulation entirely. By using neat molten AKD applied directly in the papermaking process, the patent achieves effective sizing without requiring any additional chemical substances for stabilization, thereby reducing the number of additives to zero.
3Reliability
If formulated AKD dispersions are used, then the sizing effectiveness is improved, but the process complexity increases
Solution Approach 1:
The invention extracts the AKD sizing agent from complex formulated dispersions and uses it in its native molten form. By eliminating the formulation step and using neat AKD melted and applied directly in the papermaking process, the patent maintains sizing effectiveness while dramatically simplifying the manufacturing process and eliminating the need for separate dispersion preparation.
Solution Approach 2:
The invention performs preliminary melting of AKD to prepare it for direct application. By melting the solid AKD beforehand and maintaining it in molten form during the papermaking process, the patent ensures proper application without requiring complex dispersion formulations, thereby simplifying the overall process while maintaining sizing effectiveness.
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 method provides a convenient and effective sizing agent for paper, achieving stable and hydrophobic properties in the final product without the complexity of traditional dispersion formulations, as evidenced by high contact angles and stable hydrophobicity of the resulting films.
Implementation Method 1
a second stream of a cellulosic suspension is flowed through a shearing device and in which a molten alkyl ketene dimer (AKD) is metered in to the second stream of cellulosic suspension in or prior to the shearing device
Data Source
AI summary
AKD cellulosic composition obtainable by flowing a stream of a cellulosic suspension through a shearing device and in which a molten alkyl ketene dimer (AKD) is metered in to the stream of cellulosic suspension in or prior to the shearing device. The AKD cellulosic composition is particularly suitable in the manufacture of sized paper and paperboard.