Aldehyde-Modified Copolymer for Paper Drainage and Strength
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Solution Overview
Problem
Existing paper manufacturing processes fail to simultaneously improve drainage properties and physical properties of paper.
Innovation Solution
A novel process using a cationic or amphoteric copolymer derived from the reaction between an aldehyde and a base copolymer, incorporating a polyfunctional compound with three mobile hydrogens, which acts as a dry strength, retention, drainage, and runnability aid, is introduced. This copolymer is modified by incorporating or grafting polyfunctional compounds like polyethyleneimine during polymerization, enhancing the paper's properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional drainage aids are used to improve drainage properties, then drainage improves, but physical properties such as burst strength and internal cohesion deteriorate
Solution Approach 1:
The patent uses a composite polymer structure combining cationic/acamphoteric base polymer with polyfunctional compounds (containing N, S, O, P heteroatoms) to create a multi-functional additive that simultaneously improves drainage and maintains physical paper properties. The composite nature of the polymer allows it to perform multiple functions that single-component additives cannot achieve.
Solution Approach 2:
The invention modifies the chemical parameters of the base polymer by incorporating polyfunctional compounds with specific heteroatoms (N, S, O, P) that have mobile hydrogens. This chemical modification changes the polymer's interaction properties with cellulose fibers, enabling improved drainage without sacrificing the bonding strength necessary for physical paper properties.
2Reliability
If retention aids are applied to improve fiber retention, then retention improves, but drainage properties worsen
Solution Approach 1:
The modified copolymer serves multiple functions simultaneously: it acts as both a retention aid (improving fiber retention through cationic/amphoteric interactions) and a drainage aid (enhancing water removal). The polyfunctional compounds incorporated into the base polymer enable this multi-functionality, allowing a single additive to address both retention and drainage requirements.
3Strength
If dry strength aids are used to improve dry strength, then dry strength improves, but runnability and drainage properties worsen
Solution Approach 1:
The patent creates a composite polymer system where the base cationic/amphoteric polymer provides dry strength enhancement through fiber bonding, while the incorporated polyfunctional compounds (with N, S, O, P heteroatoms) provide improved runnability and drainage properties. This composite structure allows the additive to simultaneously improve dry strength while maintaining operational ease.
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 process significantly improves drainage and physical properties such as burst strength, breaking length, and internal cohesion, while maintaining or enhancing dry strength, thereby optimizing paper production.
Implementation Method 1
the base copolymer being modified beforehand with at least one polyfunctional compound comprising at least three heteroatoms chosen from N, S, O and P, in which at least three of these heteroatoms each have at least one mobile hydrogen
Implementation Method 2
said additive is a cationic or amphoteric (co)polymer derived from the reaction between at least one aldehyde and at least one base (co)polymer
Data Source
AI summary
Process for manufacturing a sheet of paper and/or of paperboard and the like, according to which, the cellulosic material is brought into contact with at least one dry strength aid, characterized in that said dry strength aid is a cationic or amphoteric (co)polymer derived from the reaction between at least one aldehyde and at least one base (co)polymer comprising at least one nonionic monomer, said base copolymer being modified with at least one polyfunctional compound comprising at least three heteroatoms chosen from N, S, O and P, in which at least three of these heteroatoms each have at least one mobile hydrogen.