Polyacrylamide Strengthening Agents for Paper-Making Wet Strength
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Solution Overview
Problem
The paper-making industry faces challenges in achieving effective temporary wet strength using glyoxylated polyacrylamides (GPAMs) due to their short shelf life and the need for high dosages, while amphoteric polyacrylamides lack temporary wet strength enhancement, and existing combinations do not consider the impact of molecular weights and ratios of these polymers.
Innovation Solution
A paper-making process involving a combination of dialdehyde-modified polyacrylamide-type strengthening agents with specific molecular weights and amphoteric polyacrylamide-type strengthening agents in a specific ratio, applied in a paper-making process that includes steps of forming a pulp slurry, adding aqueous liquids, forming a wet paper web, pressing, and drying, to enhance temporary wet strength.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If GPAMs with higher molecular weight are used to improve temporary wet strengthening effect, then the strengthening effect is improved, but the polymer solution becomes gelled more easily and shelf life is shortened
Solution Approach 1:
The invention changes the molecular weight parameter of GPAMs from the conventional high range (>300,000 Dalton) to a lower range (100,000-300,000 Dalton), which reduces gelation tendency and extends shelf life while maintaining adequate temporary wet strengthening effect when combined with amphoteric PAM
Solution Approach 2:
The invention creates a composite strengthening system by combining GPAMs (molecular weight 100,000-300,000 Dalton) with amphoteric PAMs (molecular weight 500,000-2,000,000 Dalton) in a specific ratio range (9:1 to 1:9), where the two polymers work synergistically to provide both temporary wet strength and extended shelf life
2Duration of action of stationary object
If GPAMs with molecular weight of 100,000-300,000 Dalton are used to extend shelf life, then shelf life is improved, but temporary wet strengthening effect becomes unsatisfactory
Solution Approach 1:
The invention merges GPAMs (molecular weight 100,000-300,000 Dalton) with amphoteric PAMs (molecular weight 500,000-2,000,000 Dalton) into a combined strengthening system, where the amphoteric PAM compensates for the lower strengthening effect of the lower molecular weight GPAMs, achieving both extended shelf life and satisfactory temporary wet strength
Solution Approach 2:
The invention introduces a new parameter dimension - the molecular weight of amphoteric PAM (500,000-2,000,000 Dalton) - and optimizes the molecular weight ratio between GPAM and amphoteric PAM to achieve synergistic effect, where the higher molecular weight amphoteric PAM provides the necessary strength enhancement
3Strength
If more GPAMs with lower molecular weight are added to achieve comparable temporary wet strengthening effect, then the strengthening effect is maintained, but the dosage increases and economy decreases
Solution Approach 1:
The invention uses amphoteric PAM as a complementary agent that works synergistically with lower molecular weight GPAMs, allowing the system to achieve the same strengthening effect with reduced total polymer dosage, improving economic efficiency
Solution Approach 2:
The composite system of GPAMs (molecular weight 100,000-300,000 Dalton) and amphoteric PAMs (molecular weight 500,000-2,000,000 Dalton) creates a synergistic effect where the combination provides superior strengthening performance at lower dosages compared to using either polymer alone
Data Source
AI summary
The invention provides a process for paper-making, comprising the steps of: (a) providing a pulp slurry; (b) adding to the pulp slurry at least a first aqueous liquid and a second aqueous liquid so as to obtain a paper stock; (c) forming the paper stock obtained in the step (b) so as to obtain a wet paper web; (d) pressing and draining the wet paper web obtained in the step (c) so as to obtain a wet paper sheet; and (e) drying the wet paper sheet obtained in the step (d) so as to obtain a paper sheet. Correspondingly, the invention provides an aid composition for paper-making.