Anionic Water-Soluble Polymer for Paper Dry Strength and Drainage
Solution Overview
Problem
The paper industry faces challenges in achieving high dry strength and maintaining drainage properties in paper production due to the use of high molecular weight cationic polymers, which require complex handling and result in reduced productivity and mechanical weaknesses.
Innovation Solution
Development of an anionic water-soluble polymer through a sequential polymerization method using anionic and nonionic monomers with a structuring system, avoiding cationic monomers, to enhance dry strength and drainage while simplifying installation and reducing environmental impact.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If high molecular weight cationic polymers are used to improve dry strength, then the dry strength of paper is improved, but drainage properties are reduced and productivity decreases
Solution Approach 1:
The patent inverts the conventional approach by using anionic polymers instead of cationic polymers as the primary dry strength agent. This inversion allows the polymer to work through a different mechanism that does not interfere with drainage properties, thereby maintaining productivity while achieving improved dry strength.
Solution Approach 2:
The patent changes the charge parameter of the polymer from cationic to anionic, and optimizes molecular weight parameters to achieve the right balance between dry strength enhancement and drainage maintenance. This parameter optimization allows high molecular weight polymers to be used without the severe drainage penalties observed with conventional cationic polymers.
2Strength
If high molecular weight polymers are used to improve dry strength, then the dry strength of paper is improved, but mechanical weaknesses and aggregation occur
Solution Approach 1:
The patent optimizes the molecular weight parameter to a specific range that provides sufficient dry strength enhancement while avoiding the mechanical weaknesses and aggregation problems associated with extremely high molecular weight polymers. The anionic charge also changes the interaction mechanism with fibers, reducing aggregation.
Solution Approach 2:
The patent employs a polymer formulation that achieves effective dry strength enhancement without requiring excessive molecular weight, thereby avoiding the reliability issues. The optimized molecular weight range ensures the polymer remains soluble and does not form aggregates that would compromise paper quality.
3Ease of operation
If liquid process polymerization is used to maintain water solubility, then ease of operation is improved, but molecular weight is limited and viscosity increases
Solution Approach 1:
The patent optimizes the molecular weight parameter within the constraints of liquid process polymerization, achieving the highest effective molecular weight that maintains both water solubility and acceptable viscosity. The anionic charge and specific monomer composition enhance water solubility, allowing higher molecular weights than conventional cationic polymers.
4Strength
If gel polymerization is used to obtain high molecular weight, then dry strength is improved, but the polymer is in solid form requiring complex handling
Solution Approach 1:
The patent inverts the conventional approach by using liquid process polymerization instead of gel polymerization, and by using anionic instead of cationic polymers. This inversion allows the production of high molecular weight polymers in liquid form that remain water-soluble, eliminating the need for complex powder handling systems while maintaining dry strength performance.
Solution Approach 2:
The patent changes the polymerization process parameters and final product form from solid (gel polymerization) to liquid (liquid process polymerization), while optimizing molecular weight and charge parameters to ensure both high dry strength performance and water solubility. This allows direct use of the polymer in liquid form without dissolution steps.
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 anionic water-soluble polymer improves dry strength and maintains drainage properties, reducing the need for on-site powder handling and energy consumption, and lowers greenhouse gas emissions.
Implementation Method 1
these polymers can be attached directly on the anionic cellulose and give it a cationic charge so that, in association with anionic polymers, attachment of the latter on the cellulosic fibers occurs, thus improving the dry strength of the sheet
Implementation Method 2
a sequential polymerization method using anionic and nonionic monomers with a structuring system
Data Source
AI summary
The present invention relates to a novel anionic water-soluble polymer, to the method for the preparation thereof and to the use thereof, notably in the paper field.