In the paper industry, foam has always been an important factor affecting production efficiency and product quality. In order to effectively control this problem, papermaking defoamers have emerged and become an indispensable key additive in papermaking processes.

In papermaking process, foam is mainly produced by the use of a variety of chemical aids, such as filter aid, retention aid, wet strength agent, sizing agent, etc. These additives are prone to interact with solid substances such as fibers and pigment fillers in the slurry during the beating and white water closed cycle process, forming stable bubbles. These bubbles not only affect the fluidity of the pulp, but may also cause quality problems with the paper, such as bubble printing and uneven paper surface.

Defoamers in papermaking can effectively eliminate the foam in papermaking process by reducing the surface tension of liquid and destroying the stability of foam. According to their composition and properties, papermaking defoamers can be divided into various types such as polyethers, oils and fats, organosilicon, kerosene, and fatty alcohols. Different types of defoamers have their own characteristics and are suitable for different papermaking processes and scenarios.

Polyether defoamers have good temperature resistance and stability, and are suitable for high-temperature cooking and washing sections. Oil defoamer can effectively eliminate surface foam, but its effect on removing gas from slurry is limited. Organic silicone defoamers have a fast defoaming speed, but they require a large amount and are not cost-effective. Kerosene based defoamers are mainly used in the production of low-grade paper, but may affect the sizing effect and cause the finished paper to have a kerosene odor. Fatty alcohol defoamers can quickly remove the gas in the pulp and eliminate the foam on the water surface, have little impact on sizing, and have low cost. They are the development direction of paper defoamers at present.

The position and amount of defoamer added in the papermaking process are crucial for the defoaming effect. Generally speaking, defoamers in the pulp making section are mainly added to the bleaching and washing sections, while defoamers in the papermaking section are added to the paper machine's flow box, pulp tank, coating and sizing press. Reasonable addition of location and appropriate amount of defoamer can significantly improve papermaking efficiency, improve paper quality, and reduce the occurrence of paper breakage and other faults.

With the continuous development of the paper industry and the increasing demand for environmental protection, paper defoamers will pay more attention to environmental friendliness, efficiency, and multifunctionality. In the future, the development of low toxicity, low volatility, and easily biodegradable defoamers will become the mainstream trend. At the same time, the application of intelligent technology will also promote the automation control and precise addition of defoamers in papermaking, further improving the efficiency and stability of papermaking production.