Filler Aggregate Composition Using Nanofibrillar Cellulose
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Solution Overview
Problem
The pulp and paper industry faces challenges in increasing filler content in paper products without compromising mechanical strength, as high filler levels can disrupt fibre-fibre bonding and lead to delamination issues during printing.
Innovation Solution
A filler aggregate composition combining ground calcium carbonate, a pretreatment agent such as polyvinylamine or cationic polyacrylamide, and nanofibrillar cellulose is used, which forms larger aggregates that enhance floc stability and size, allowing for higher filler loads while maintaining paper strength.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If filler content is increased to reduce cost and improve printability, then cost reduction and printability improvement are achieved, but mechanical strength decreases due to disrupted fibre-fibre bonding
Solution Approach 1:
The patent introduces nanofibrillar cellulose as an intermediary substance between filler particles and fibres. The NFC creates bridging structures that connect filler aggregates to the fibre network, allowing high filler content to be incorporated while maintaining mechanical strength through this mediating cellular structure.
Solution Approach 2:
The invention creates a composite structure where filler particles are aggregated with nanofibrillar cellulose to form filler-NFC complexes. This composite approach allows the beneficial properties of both components to be combined: the cost-effectiveness and printability improvement from high filler content, and the strength enhancement from the NFC-reinforced matrix.
2Illumination intensity
If filler content is increased to improve optical properties, then optical quality improves, but paper product strength decreases due to reduced fibre contact
Solution Approach 1:
Nanofibrillar cellulose acts as a mediating structure that maintains the fibre network integrity even at high filler concentrations. The NFC creates a continuous phase that connects fibres and binds filler particles, ensuring that optical properties are enhanced by filler while mechanical strength is preserved through the NFC-fibre framework.
Solution Approach 2:
The patent applies local quality by creating distinct regions: filler-NFC aggregates provide optical enhancement in specific zones, while the NFC-reinforced fibre network maintains structural strength in load-bearing regions. This spatial differentiation allows simultaneous optimization of optical and mechanical properties.
3Quantity of substance
If filler disrupts fibre-fibre bonding network to enable higher filler load, then filler content increases, but fibre-fibre bonding is reduced leading to delamination
Solution Approach 1:
The nanofibrillar cellulose serves as a reliable intermediary that reconstructs the bonding network. Instead of allowing filler particles to directly disrupt fibre-fibre contacts, the NFC creates alternative bonding pathways through its extensive network, ensuring that high filler loads do not compromise the reliability of the overall structure.
Solution Approach 2:
The patent applies preliminary action by pre-forming filler-NFC aggregates before incorporating them into the fibre suspension. This pre-aggregation ensures that filler particles are already bound to NFC structures that will integrate with the fibre network, preventing subsequent disruption of fibre-fibre bonding during paper formation.
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 composition achieves a synergistic effect, increasing floc size and stability, enabling higher filler content in paper products without sacrificing mechanical properties, thus improving printability and optical qualities.
Implementation Method 1
a pretreatment agent selected from polyvinylamine (PVAM) and cationic polyacrylamide (CPAM)... which are cationic polymers that interact electrostatically with the negatively charged filler particle surfaces
Implementation Method 2
nanofibrillar cellulose (NFC)... the nanofibrillar cellulose is present in an amount of about 0.1-40% of the dry weight of the filler particles... forms larger aggregates that enhance floc stability and size
Implementation Method 3
By using a combination of filler, polymer and nanofibrillar cellulose according to the present invention a synergistic effect is obtained of the flocculating properties of a formed aggregate composition
Data Source
AI summary
The present invention relates to a filler aggregate composition comprising filler particles of ground calcium carbonate (GCC); a pretreatment agent selected from polyvinylamine (PVAM) and cationic polyacrylamide (CPAM), or a mixture thereof; and a nanofibrillar cellulose (NFC); wherein said filler aggregate composition is in the form of a slurry, wherein said pretreatment agent has an average molecular weight below 6000000 g/mol and a has a charge density below 7 meq/g, determined at pH 7, and the nanofibrillar cellulose is present in an amount of about 0.1-40% of the dry weight of the filler particles. Further it also relates to its method of production, and its use in stocks, paper and paper board.