In the paper industry, Poly(dimethyldiallylammonium chloride), as a kind of cationic organic polymer flocculant, is widely used in processes such as retention aid, filtration aid and paper strength enhancement. It can improve the retention of fine fibers and fillers, optimize the pulp dewatering process, and enhance the physical properties of paper.
1. Mechanism of improving paper strength
1.1 Giving fibers a better bond
In the papermaking process, the strength of paper mainly depends on the hydrogen bond strength between fibers.
Poly(dimethyldiallylammonium chloride) is a strong cationic polymer, which can have electrostatic adsorption with the anionic groups on the surface of fibers (such as carboxyl group and sulfonic acid group) to make the contact between the fibers closer and improve the bonding strength between the fibers, thus enhancing the dry and wet strength of the paper.
1.2 Reduce charge shielding, improve fiber binding capacity
Pulp system, there are a large number of negatively charged microfibers, fillers and anionic impurities (such as lignin, anionic garbage, etc.), these substances will impede the combination of fibers.
As a strong cationic polymer, poly(dimethyldiallyl ammonium chloride) can neutralize the anionic impurities in the pulp and reduce the charge repulsion effect, thus improving the physical bonding between the fibers and making the paper more compact and stronger.
1.3 Promote the adsorption of wet strength agent
Poly(dimethyldiallyl ammonium chloride) can also improve the adsorption of wet strength agent (such as polyamide-epichlorohydrin (PAE)), so that it is uniformly distributed in the structure of the paper, thus further enhancing the wet strength of the paper.
2. Role in retention and filtration aid
2.1 Improve the retention rate of fillers and fine fibers
In the papermaking process, fine fibers and fillers (such as calcium carbonate, talc, silica, etc.) are easy to lose with water, reducing the quality of paper and production efficiency.
Dimethyldiallylammonium chloride through the charge neutralization effect, so that the fine fibers and fillers are more easily adhered to the larger fibers, to improve their retention rate in the pulp, reducing the waste of raw materials.
This not only reduces paper chalking and improves the surface quality of paper, but also reduces the burden on the white water recovery system and improves the economic efficiency of the paper mill.
2.2 Optimize pulp dewatering, improve water filtration performance
As polydimethyl diallylammonium chloride can aggregate and bridge fine fibers, so that they are deposited on the screen faster, reducing the phenomenon of tiny fibers blocking the screen, thus accelerating the removal of water and improving the performance of pulp dehydration.
This is essential to improve the production speed of the paper machine, which can reduce energy consumption and improve production efficiency.
2.3 Cooperate with the retention and filtration system to improve the overall effect
In the papermaking process, polydimethyl diallylammonium chloride is usually used in conjunction with other retention and filtration aids (such as polyacrylamide (PAM), colloidal silica, bentonite, etc.) to form a more effective retention and filtration aid system to further improve the retention rate of the pulp and filtration water.
3. Advantages of using polydimethyl diallylammonium chloride
Improve paper quality: enhance paper strength, reduce chalking and improve uniformity.
Reduces chemical usage: Reduces the need for other chemical additives (e.g., anionic trash control agents, filter aids) and optimizes paper production costs.
Improved papermaking efficiency: Reduces loss of fine fibers and fillers in white water, improves water filtration efficiency, and increases production speed.
Environmental protection advantage: reduce the pressure of pulp wastewater treatment, reduce water pollution, and improve the environmental compliance rate of the mill.
4. Typical application areas
Cultural paper (copy paper, printing paper): improve paper strength and uniformity, improve printing adaptability.
Packaging paper (boxboard, corrugated paper): to enhance the strength of paper breakage resistance, folding strength, improve water resistance.
Specialty paper (filter paper, thermal paper): optimize surface properties, enhance abrasion resistance and moisture resistance.
5. Conclusion
As a cationic additive, polydimethyl diallylammonium chloride plays a vital role in the paper industry. It not only improves paper strength and makes the fibers more tightly bound, but also effectively assists retention and filtration, improves production efficiency and optimizes the stability of the pulp system. As the paper industry's demand for environmentally friendly and high-performance paper grows, it is expected that the application prospects of polydimethyl diallylammonium chloride will be even broader.
If you have more questions about the specific application, usage or purchasing requirements of polydimethyldiallyl ammonium chloride in the paper industry, please feel free to communicate further!