High-Solids CMC Solution With Low Viscosity and Pumpability
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Solution Overview
Problem
Existing methods struggle to produce high solids content carboxymethylcellulose (CMC) solutions with high molecular weight CMC while maintaining low viscosity and pumpability, limiting their effectiveness in applications such as paper and board coatings.
Innovation Solution
A method involving the combination of low and high molecular weight CMCs, where high molecular weight CMC is added as a solid, preferably in powder form, to an aqueous solution of low molecular weight CMC, achieving a total CMC content of at least 18 wt.% with a viscosity of 5000 mPas or less.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If high molecular weight CMC is used to improve barrier properties and film hold-out, then the solids content and viscosity of the solution increase, but pumpability deteriorates
Solution Approach 1:
The CMC population is segmented into different molecular weight ranges (high, medium, low). This segmentation allows each fraction to contribute differently: high Mw provides barrier properties while lower Mw fractions maintain solution流动性 and pumpability, resolving the contradiction between reliability and ease of operation.
Solution Approach 2:
The invention changes the parameter distribution of molecular weights rather than using a single high Mw CMC. By controlling the molecular weight distribution parameters (achieving at least 30% high Mw CMC while maintaining overall solution viscosity below 5000 mPas), the solution achieves both high barrier performance and good pumpability.
2Reliability
If CMC concentration is increased to improve barrier properties, then solids content increases, but viscosity increases excessively
Solution Approach 1:
The CMC is segmented into molecular weight fractions where high Mw CMC (≥100 kDa) provides barrier properties and medium/low Mw CMC maintains solution流动性. This allows achieving at least 18 wt.% total CMC solids while keeping viscosity below 5000 mPas, resolving the contradiction between reliability and force.
Solution Approach 2:
The invention creates a composite CMC system combining multiple molecular weight fractions in specific proportions (at least 30% high Mw, with controlled medium and low Mw content). This composite approach allows the system to achieve high solids content for barrier properties while the lower Mw components maintain low viscosity, resolving the contradiction between reliability and force.
3Quantity of substance
If CMC is degraded to achieve higher solids content, then concentration increases, but molecular weight decreases and film hold-out deteriorates
Solution Approach 1:
Instead of degrading high Mw CMC to increase solids content (conventional approach), the invention inverts the approach by combining high Mw CMC with lower Mw CMC. This maintains high molecular weight for film hold-out while achieving high solids content through the combined system, resolving the contradiction between quantity of substance and reliability.
Solution Approach 2:
The invention creates a composite CMC system where high Mw CMC (≥100 kDa) comprising at least 30% of total CMC provides film hold-out, while medium and low Mw CMC contribute to solids content. This composite approach achieves at least 18 wt.% total solids while maintaining excellent film hold-out properties, resolving the contradiction between quantity of substance and reliability.
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 method allows for higher total solids content of CMC solutions with improved rheological properties, enhancing their suitability for paper and board coatings without the need for stabilizing agents and maintaining low viscosity.
Implementation Method 1
The CMC solution may find use as a thickener in a number of applications... The presence of the gel network structure provided by the high molecular weight CMC...
Implementation Method 2
The low molecular weight CMC acts as a dispersing agent... ensuring that the high molecular weight CMC remains well-dispersed and does not aggregate
Data Source
AI summary
The present invention relates to a method for producing a carboxymethylcellulose (CMC) solution, the method comprising the following steps: a) obtaining an aqueous solution comprising at least one low molecular weight CMC having a weight average molecular weight of less than 30kDa; and b) dissolving at least one high molecular weight CMC having a weight average molecular weight of at least 30kDa into the solution of step a), wherein the at least one high molecular weight CMC is added as a solid (preferably as a powder) to the solution of step a), wherein the amount of low and high molecular weight CMC added in steps a) and b), respectively, is such that the total amount of CMC in the solution is at least 18 wt.% (relative to the total weight of the CMC solution).