Three-Component Polymer System for Paper Dry Strength
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Solution Overview
Problem
Existing methods for enhancing paper dry strength using two-component systems of cationic and anionic polymers are not fully satisfactory, particularly in terms of polymer quantities required and wet strength characteristics, leading to process difficulties such as sheet reduction to pulp during recycling.
Innovation Solution
A three-component system comprising a cationic polymer with primary amine functions, a synthetic organic polymer with cationic filler density higher than 0.1 meq/g, and an anionic polymer is introduced into the paper fibrous suspension to improve dry strength, with each component added separately or mixed at various injection points, optimizing their synergistic action.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If two-component systems of cationic and anionic polymers are used to enhance paper dry strength, then dry strength is improved, but polymer quantities required increase and wet strength characteristics deteriorate
Solution Approach 1:
The patent applies composite materials by combining three specific polymer components (cationic polymer with primary amine functions, synthetic organic polymer with cationic filler density >0.1 meq/g, and anionic polymer) into a three-component system. This composite approach creates synergistic interactions between the components that enhance dry strength more effectively than two-component systems, while reducing the total polymer quantity required and maintaining better wet strength characteristics.
2Strength
If two-component systems of cationic and anionic polymers are used to enhance paper dry strength, then dry strength is improved, but process difficulties occur during recycling
Solution Approach 1:
The three-component composite system is designed to improve dry strength while maintaining compatibility with recycling processes. The specific selection of polymers with defined charge densities and functional groups creates a balanced system that enhances paper strength without causing excessive sheet reduction or processing difficulties during pulp recycling, unlike conventional two-component systems.
3Strength
If conventional cationic polymers are used to improve dry strength, then dry strength is enhanced, but wet strength characteristics and economic efficiency deteriorate
Solution Approach 1:
The patent employs a composite three-component system that achieves superior dry strength at lower polymer dosages compared to conventional single or two-component systems. This composite approach improves economic efficiency by reducing the total amount of polymer chemicals required per ton of paper produced, while simultaneously maintaining or improving wet strength characteristics through the synergistic interaction of the three components.
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
This approach achieves unprecedented dry strength performance, including high burst and tensile strength without negative side effects, while being economically more favorable than previous methods.
Implementation Method 1
They can be fixed directly on the anionic cellulose and give it a cationic filler
Implementation Method 2
in combination with anionic polymers, the latter are fixed on the cellulose fibres
Data Source
AI summary
A method for making a sheet of paper and/or cardboard and the like, comprises, prior to forming said sheet, adding to the fibrous suspension, separately or mixed, in any sequence of introduction, into one or more injection points, at least three dry strength agents respectively: first agent corresponding to a (co)polymer having a cationic filler density higher than 1 meq/g and exhibiting primary amine functions; a second agent corresponding to a synthetic organic (co)polymer having cationic filler density higher than 0.1 meq/g; and a third agent corresponding to a (co)polymer having an anionic filler density higher than 0.1 meq/g.