Activated Polymer Retention in Papermaking
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Solution Overview
Problem
Current papermaking processes face challenges in achieving efficient retention and drainage of fines and fillers, leading to increased costs and environmental impacts due to the loss of materials and poor formation quality, as conventional high molecular weight polymers often compromise between retention and formation when added after a high shear point.
Innovation Solution
The use of water-soluble, high molecular weight polymers with hydrolyzable cross-linked monomer units that are activated to increase viscosity, allowing for effective retention and drainage as RDF aids by being introduced before the high shear point, thereby improving retention and drainage efficiency while maintaining paper formation quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of substance
If high molecular weight polymers are added after a high shear point to improve retention, then retention of fines and fillers increases, but formation quality deteriorates due to floc formation and breakdown issues
Solution Approach 1:
The polymer is added before the high shear point in the papermaking process, allowing floc formation to occur in a low-shear environment where flocs can develop properly without being broken down. This preliminary action enables the polymer to perform its retention function effectively while avoiding the formation problems that occur when polymer is added after the high shear point.
2Productivity
If high molecular weight polymers are used as flocculants to increase drainage efficiency, then drainage rate improves, but formation quality compromises due to excessive floc formation
Solution Approach 1:
The invention applies different qualities to different regions of the papermaking process by adding the polymer before the high shear point where floc formation is beneficial for drainage, while the subsequent high shear region naturally breaks down excessive flocs to maintain formation quality. This spatial differentiation of floc size and structure resolves the contradiction between drainage efficiency and formation quality.
3Loss of substance
If conventional polymers are used to achieve high retention levels of 80-90%, then retention of furnish components improves, but formation parameter declines significantly
Solution Approach 1:
By adding the polymer before the high shear point, the system allows floc formation to occur in advance under controlled conditions. The subsequent high shear processing then optimizes the floc structure to maintain both high retention and acceptable formation, resolving the trade-off that plagues conventional approaches.
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 activated polymer composition enhances retention and drainage in papermaking processes, reducing material losses and environmental impacts, and allows for lower dosages compared to conventional polymers, thereby decreasing costs and improving paper quality.
Implementation Method 1
the polymers are temporarily cross-linked via hydrolyzable cross-linkers. The cross-linkers can be hydrolyzed prior to addition to the papermaking process, providing a more viscous, high molecular weight, water soluble polymer solution
Data Source
AI summary
Disclosed herein are methods of increasing retention and drainage in papermaking processes using high molecular-weight, water-soluble polymers.