Polymer Complex for Paper Dry Strength via Segmentation
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Solution Overview
Problem
Existing polymer complexes used as dry strength agents in paper and cardboard production suffer from phase separation and high viscosity, leading to instability and short shelf-life, making them difficult to incorporate into low-viscosity solutions.
Innovation Solution
A polymer complex is developed by polymerizing water-soluble monomers in the presence of a water-soluble host polymer with vinylamine functions and a non-polymeric transfer agent, without branching or crosslinking agents, to create a stable and homogeneous mixture that acts as a crosslinker or branching agent, controlling polymer chain length and preventing phase separation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If polymers of different molecular weights are added to cellulose suspension to improve paper properties, then the strength characteristics of paper are enhanced, but phase separation occurs during dissolution making homogenous composition difficult to prepare
Solution Approach 1:
The patent divides the polymer system into distinct segments: a host polymer and guest polymers of different molecular weights. These segmented polymer components are introduced separately into the cellulose suspension, allowing each to interact with cellulose independently while maintaining overall homogeneity, thus preventing phase separation while enhancing paper strength.
Solution Approach 2:
The patent changes the molecular weight parameters of the polymers used, employing a combination of high and low molecular weight polymers. By carefully selecting and controlling these molecular weight parameters, the patent achieves optimal paper strength enhancement while maintaining homogenous composition during dissolution and processing.
2Stability of the object's composition
If existing polymer complexes are used as dry strength agents, then phase separation is mitigated, but viscosity becomes excessively high making incorporation into low-viscosity solutions difficult
Solution Approach 1:
The patent applies local quality by creating a core-shell structure where the host polymer forms a core with controlled viscosity characteristics, while guest polymers form a shell with different rheological properties. This local differentiation allows the complex to maintain low overall viscosity for easy incorporation into solutions while the internal structure prevents phase separation.
Solution Approach 2:
The patent creates a composite polymer complex combining host and guest polymers with complementary properties. The host polymer provides structural integrity and phase stability, while the guest polymers contribute to low viscosity and ease of processing. This composite material approach simultaneously achieves homogeneity and low viscosity.
3Stability of the object's composition
If high viscosity polymer complexes are used to prevent phase separation, then homogeneity is maintained, but shelf-life decreases due to viscosity increase over time
Solution Approach 1:
The patent creates a dynamic polymer complex where the host and guest polymers maintain reversible interactions. This dynamic structure allows the complex to adapt its conformation over time, preventing permanent aggregation and viscosity increase. The reversible nature of the interactions ensures long-term stability and extended shelf-life while maintaining homogeneity.
Solution Approach 2:
The host polymer in the patent performs self-service by actively preventing phase separation through its inherent structural properties and interactions with guest polymers. This self-stabilizing mechanism eliminates the need for additional stabilizing agents that could increase viscosity, thereby maintaining low viscosity and extending shelf-life while ensuring long-term homogeneity.
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 resulting polymer complex is stable over time, prevents phase separation, and enhances the mechanical properties of paper and cardboard as a dry strength agent, improving their dry strength performance without increasing viscosity.
Implementation Method 1
polymerization of one or more water-soluble monomers in the presence of a previously prepared polymer
Implementation Method 2
increase the number of inter-fiber hydrogen bonds so as to improve the strength of the paper in its dry state
Data Source
AI summary
The present invention relates to a complex of polymers and to the use thereof in a method of making paper, cardboard or the like. This complex of polymers is obtained by polymerizing water-soluble monomers: in the presence of a host polymer that comprises vinylamine functions and of a non-polymeric transfer agent, and in the absence of a branching or crosslinking agent of the ethylenic polyfunctional type. It is obtained as from a mass ratio of anionic monomer to water that is greater than 0.035.