Jet Cooked MFC Starch Dispersion for Paper Surface Sizing
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Solution Overview
Problem
Existing surface sizing methods for paper and board products face challenges with high viscosity and low solid content when using microfibrillated cellulose (MFC) and starch, which worsen dusting tendencies due to increased filler contents, necessitating a method that balances these issues.
Innovation Solution
An aqueous dispersion of microfibrillated cellulose, starch, and pigment/filler treated by jet cooking is used for surface sizing, reducing viscosity while maintaining dusting reduction benefits.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-generated harmful factors
If starch and MFC are used in surface sizing to reduce dusting tendency, then dusting is reduced, but viscosity becomes too high and solid content becomes low
Solution Approach 1:
The patent applies parameter changes by modifying the dispersion process through jet cooking at controlled temperatures (80-120°C) for specific durations (5-60 minutes). This thermal treatment alters the rheological properties of the MFC-starch-pigment dispersion, reducing extensional viscosity while maintaining the dusting-reducing benefits of MFC and starch combinations.
Solution Approach 2:
The patent employs preliminary action by pre-treating the MFC-starch-pigment dispersion through jet cooking before application to the paper surface. This pre-cooking step prepares the dispersion with optimized viscosity characteristics, ensuring proper flow and deposition properties while maintaining the dusting control functionality of the MFC-starch system.
2Quantity of substance
If filler content is increased to maintain production costs, then production costs are controlled, but bonding within paper is weakened and dusting tendency increases
Solution Approach 1:
The patent uses composite materials by combining MFC, starch, and pigment/filler in a multi-component surface sizing dispersion. The MFC-starch matrix provides enhanced bonding strength that compensates for the presence of fillers, while the jet cooking process optimizes the interaction between these components to maintain both bonding and dusting control despite high filler contents (6-50 kg per ton dry paper).
3Object-generated harmful factors
If MFC and starch are used for surface sizing, then dusting tendency is reduced, but extensional viscosity becomes too high
Solution Approach 1:
The patent applies parameter changes through controlled jet cooking treatment that specifically targets extensional viscosity reduction. The thermal processing at 80-120°C for 5-60 minutes modifies the molecular structure and interactions in the MFC-starch dispersion, lowering extensional viscosity while preserving the dusting control properties. This enables the dispersion to flow more easily during application without compromising its dusting-reducing functionality.
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 effectively reduces dusting tendencies while avoiding high viscosity issues, achieving improved print quality and production efficiency with controlled filler contents.
Implementation Method 1
jet cooking the dispersion of step a) or b)
Implementation Method 2
adding oxidizing agents and/or enzymes to the dispersion of step a)
Data Source
AI summary
The present invention relates to a process for improved surface sizing in the manufacture of paper or board products. According to the present invention, an aqueous dispersion of microfibrillated cellulose (MFC), starch and pigments or fillers is treated by jet cooking and then used for surface sizing in a process for manufacturing a paper or board product.