Anionic Polymer Composition for Paper Wet Strength
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Solution Overview
Problem
Current wet strength additives for paper products, such as polyamidoamine epichlorohydrin (PAE), require high dosages that lead to poor retention, operational issues, and environmental problems, while alternatives like synthetic copolymers of acrylamide and acrylic acid have limitations in strength development and operating windows.
Innovation Solution
A new anionic polymer composition combining anionic polyacrylamide (APAM) and carboxymethyl cellulose (CMC) with a weight ratio of 1:10 to 10:1, providing improved wet and dry tensile strength, easier handling, and a broader operating window, facilitating better fixation of cationic additives and reducing production issues.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If high dosage of PAE resin is used to provide desired wet strength, then wet strength is improved, but PAE retention deteriorates and operational issues arise
Solution Approach 1:
The patent introduces a polymer blend consisting of anionic polyacrylamide (APAM) and carboxymethyl cellulose (CMC) as an intermediary system. This blend acts as a mediator that enhances PAE retention through synergistic mechanisms: APAM provides cationic sites for PAE binding while CMC forms hydrogen bonds with PAE, creating a multi-point attachment system that prevents PAE washout and operational issues associated with high dosage application
2Strength
If high dosage of PAE resin is used to provide desired wet strength, then wet strength is improved, but production operational issues worsen
Solution Approach 1:
The polymer blend of APAM and CMC serves as an intermediary that facilitates PAE retention at lower dosages, thereby eliminating the operational problems (drainage issues, wire and felt plugging, sheet defects) that arise from high PAE dosage application. The blend creates a retention mechanism that allows effective wet strength development without the operational disruptions caused by excessive un-retained PAE resin
3Ease of operation
If synthetic copolymer of acrylamide and acrylic acid is used as alternative to CMC, then ease of handling is improved, but strength development deteriorates
Solution Approach 1:
The patent creates a composite polymer system by blending APAM (synthetic, easy to handle) with CMC (natural, high strength development). This composite material combines the advantages of both components: the handling ease and solution stability of synthetic APAM with the superior strength development capabilities of natural CMC, thereby resolving the trade-off between ease of handling and strength development
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 polymer composition achieves superior strength performance compared to conventional synthetic anionic solution polymers, with improved handling and storage efficiency, and allows for increased dosage of cationic additives, enhancing paper strength while reducing grammage and filler effects.
Implementation Method 1
the interaction between azetidinium groups and the anionic sites on fibers and fines (primarily carboxyl groups)
Implementation Method 2
CMC normally carries relatively high anionic charge density and can effectively convert pulp suspensions to have negative charge
Data Source
AI summary
The present invention relates to a polymer composition comprising an anionic synthetic polymer and an anionic polysaccharide. The present invention further relates to a strength additive system, uses thereof, a paper product and a method of production.