Michael Addition Adducts for Paper Dry Strength
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Solution Overview
Problem
Current polyvinylamine alternatives in the papermaking industry have limitations due to reduced cationic charge density and altered physical properties when modified, affecting their binding affinity and crosslinking abilities.
Innovation Solution
The Michael addition reaction between vinylamine and α,β-unsaturated alkyl carbonyl compounds, such as acrylamide, modifies the polyvinylamine backbone, converting primary amines to secondary amines and forming branched amide groups, which enhances intermolecular interactions and reduces water binding, thereby improving dry strength and retention properties in paper products.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If polyvinylamine is modified through copolymerization with additional vinyl monomers, then water solubility and processability are improved, but cationic charge density is reduced
Solution Approach 1:
The patent changes the chemical parameters of polyvinylamine by controlling the degree of hydrolysis and the ratio of vinylamine units to other vinyl units in the copolymer. By adjusting these parameters, the patent achieves optimal balance between water solubility and cationic charge density for papermaking applications.
2Adaptability or versatility
If polyvinylamine is copolymerized with additional vinyl units, then processability and application versatility are improved, but binding affinity to pulp fiber is reduced
Solution Approach 1:
The patent creates local quality variations in the copolymer structure by distributing vinylamine units and other vinyl units in specific sequences and ratios. This local structural control ensures sufficient binding affinity at the fiber-additive interface while maintaining overall processability and application versatility.
3Reliability
If polyvinylamine is quaternized to enhance flocculation ability, then flocculation performance is improved, but molecular structure integrity is compromised
Solution Approach 1:
The patent performs preliminary copolymerization to incorporate functional vinyl units before quaternization. This preliminary structural arrangement protects the molecular backbone integrity during subsequent quaternization, maintaining molecular structure stability while achieving enhanced flocculation performance.
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 Michael addition adducts provide improved or equivalent dry strength and enhanced drainage and retention properties in paper products, maintaining effectiveness at low treatment levels, while maintaining molecular structure integrity in aqueous media.
Implementation Method 1
the unsaturated double bond subsequently becomes saturated... through a nucleophilic addition of the primary amines of vinylamine, preferably polyvinylamine to the unsaturated moiety to form N-C linkages
Implementation Method 2
Polyvinylamine has a linear backbone structure with no branches and possesses one primary amine group for every two carbon units. The polymer is highly cationic in an aqueous system with a broad pH range due to the high density of the primary amine. Thus, it has a strong hydrogen bonding ability
Data Source
AI summary
Several Michael addition adducts of vinylamines with a,ß.-unsaturated alky! carbonyl compounds including amides, esters and acids, particularly acrylamide are presented. Additionally, a process for producing these Michael addition adducts is described. These adducts are generally useful in the manufacture of paper and are particularly useful as dry strength additives to make paperboard products using a papermaking machine.