High Basis Weight Paper Retention Using Polymer Combinations
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Solution Overview
Problem
Existing papermaking processes struggle to simultaneously improve both retention and drainage, especially in high basis weight papers like packaging papers and cardboard, where both factors are crucial but often not adequately addressed by prior art combinations of retention and drainage aids.
Innovation Solution
A process involving a combination of at least one amino-containing polymer and one branched cationic polyacrylamide as retention and drainage aids, used in the papermaking process to form high basis weight papers without finely divided inorganic flocculants, optimizing both retention and drainage performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If modified polyethylenimines are used as retention and drainage aids, then drainage is effectively accelerated, but filler retention and fiber retention show weaknesses
Solution Approach 1:
The patent combines modified polyethylenimines with cationic polyacrylamides to create a synergistic retention and drainage aid system. This merging allows the polyethylenimine component to provide drainage acceleration while the cationic polyacrylamide component compensates for filler retention weaknesses, achieving both improved drainage speed and maintained filler retention simultaneously.
Solution Approach 2:
The invention uses a composite polymer system consisting of modified polyethylenimines and cationic polyacrylamides. This composite material approach leverages the complementary properties of both polymers: the polyethylenimine provides drainage enhancement while the cationic polyacrylamide ensures adequate filler and fiber retention, resolving the contradiction between drainage speed and retention reliability.
2Reliability
If cationic polyacrylamides are used as retention aids, then filler retention is improved, but drainage action is not effectively accelerated
Solution Approach 1:
The patent merges cationic polyacrylamides with modified polyethylenimines to create a balanced retention and drainage aid system. In this combination, the cationic polyacrylamide provides filler retention while the modified polyethylenimine component simultaneously accelerates drainage, eliminating the limitation of using cationic polyacrylamides alone.
Solution Approach 2:
The invention employs a composite polymer system where cationic polyacrylamides are combined with modified polyethylenimines. This composite material approach allows the system to achieve both adequate filler retention (from the polyacrylamide) and effective drainage acceleration (from the polyethylenimine), resolving the contradiction between retention reliability and drainage speed.
3Reliability
If microparticle systems with inorganic flocculants are used, then retention is improved, but process complexity and environmental impact increase
Solution Approach 1:
The patent extracts and eliminates inorganic microparticles (such as bentonite or colloidal silica) from the retention and drainage aid system. Instead of relying on inorganic flocculants, the invention achieves adequate retention performance through the synergistic combination of organic polymers (modified polyethylenimines and cationic polyacrylamides), thereby simplifying the process and reducing environmental impact while maintaining filler retention reliability.
Solution Approach 2:
The invention replaces inorganic microparticles with water-soluble organic polymers that can be easily removed from the final paper product. The polymers perform their retention function during the papermaking process and then decompose or wash away, leaving no persistent inorganic residues, thus simplifying the overall process and improving environmental compatibility.
4Reliability
If linear polyacrylamides are used in combination with polyethylenimines, then both retention and drainage are addressed, but charge density optimization is required
Solution Approach 1:
The patent optimizes the charge density parameter of the cationic polyacrylamide component to achieve the desired balance between filler retention and drainage acceleration. By carefully controlling the charge density (typically in the range of 1-10 meq/g), the system achieves adequate retention without excessive drainage acceleration, allowing for versatile application across different paper types while maintaining process simplicity.
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 achieves improved retention and drainage in high basis weight papers, enhancing filler retention and drainage efficiency, particularly in papers with basis weights above 300 g/m², making it suitable for packaging papers and cardboard production.
Implementation Method 1
by draining a paper pulp on a wire in the presence of a combination of at least one amino-containing polymer and at least one branched cationic polyacrylamide as retention and drainage aids
Implementation Method 2
effective acceleration of drainage and formation
Data Source
AI summary
A process for producing paper of high basis weight by draining a paper pulp on a wire in the presence of a combination of at least two polymers as a retention and drainage aid system, forming sheets, and drying the sheets, which comprises forming the sheets in the absence of finely divided inorganic flocculants and using as retention and drainage aids(a) at least one amino-containing polymerand(b) at least one branched cationic polyacrylamide.