Wet End Chemistry – Papermaking Process Additives
Chemical additives are used in the papermaking process for many different reasons, and they are often divided into two groups. Functional chemicals directly improve properties of the sheet, while process chemicals affect operations on or near the paper machine. This module covers the second group – process chemicals. It discusses the purpose of some of the more common process additives used on paper and board machines, and describes how they work.
Demos + Pricing
Learn more about our courses, get pricing, and see our platform.
Course Details
Learning Objectives
• Describe the composition of papermaking furnishes • Differentiate between the two classes of papermaking additives • Describe the composition of “anionic trash” • Describe the purpose and function of common paper and board machine process additives, including pH control chemicals, charge neutralizers, retention and drainage aids, pitch control additives, biocides, and foam control additives
Specs
Frequently Asked Questions
How do papermaking process additives differ from functional papermaking additives?
Where does “anionic trash” come from?
Why is good retention important?
What is the best pitch control additive for my machine?
What is the difference between a defoamer and an antifoamer?
Sample Video Transcript
In Acid Systems, Alum can be used to attach pitch to fibers. In Alkaline Systems, dispersants can be used to prevent the pitch from precipitating. Or fillers like Talc can be added to precipitate the pitch on to the furnish so it is carried out with the sheet. Alternatively, calcium and magnesium levels can be reduced or key lading agents can be used to deactivate them in order to prevent the precipitation of pitch. The best approach for a given mill and machine must often be determined by trial and error.
