Foam is a constant presence throughout the papermaking process. Pulping and cooking, washing and screening, bleaching, papermaking and even effluent treatment all generate large amounts of foam from mechanical agitation, chemical additives and the natural surface-active substances in the pulp. In 2026, high-speed machines deliver stronger shear, white water circuits are more closed, and the share of deinked and recycled pulp keeps rising, making foam problems more complex than before. Choosing the right antifoam for each section is one of the fundamentals of papermaking process management.
Pulping and papermaking have very different requirements
Foam in the pulping section comes mainly from resin, lignin and saponified matter during cooking and washing; the system runs hot and strongly alkaline, so the antifoam needs both heat and alkali resistance and strong foam-breaking power. Foam in the papermaking section is mostly related to wet-end chemicals such as retention and drainage aids and sizing agents, where compatibility between the antifoam and the wet-end system matters more, to keep oily substances from forming spots on the sheet or affecting sizing. Using one product all the way through usually satisfies neither end.
The coating section is yet another operating condition
In coated paper production, pigment slurries, latex and thickeners in the coating colour are likewise major foam generators. If foam in the coating stage is not handled properly, it leaves pinholes and streaks in the coating layer and directly affects printability. The antifoam for this stage must both deaerate quickly and interfere as little as possible with the coating colour, which is different again from the requirements of the pulping and papermaking sections, and it must be evaluated separately as well.
Wet-end chemicals: compatibility is the hidden reef
Papermaking uses large amounts of starch, polyacrylamide retention aids and various surfactants; these substances change how stable the foam is and may also interact with the antifoam. A poor selection can interfere with retention or leave oil spots and white specks on the sheet. Running a lab trial in the wet-end system before full use, observing the effect on pulp retention and sheet appearance, is the prudent approach.
Environmental requirements are raising the bar
Papermaking antifoams are moving from high-residue, hard-to-degrade products toward low-VOC, readily biodegradable ones. As wastewater discharge standards and green factory assessments tighten, products combining efficient foam breaking with environmental friendliness are increasingly favoured by mills; the market is also concentrating around suppliers with both technical strength and scale, while low-end, undifferentiated products are being phased out.
Only by coordinating antifoam selection with the characteristics of each section, wet-end compatibility and environmental requirements can stable production go hand in hand with a higher grade of finished product. Choose by section, run lab trials, and keep records for review; take these three steps steadily and this old problem of foam can be managed with clarity. Chemitech provides section-by-section selection guidance and on-site technical support for papermaking antifoams, helping mills resolve foam problems at the source.