UCARFLOC™ - Retention Aids for Papermaking

Effective and Efficient Paper Retention Aids

 

Recently, the cost of paper has risen due to higher transportation expenses and more frequent pulp mill downtimes caused by labor shortages. Consequently, paper mills have prioritized reducing operating costs by enhancing efficiency. The papermaking process involves numerous steps from pulp to paper. One significant improvement in efficiency has been the selection of appropriate retention aids. These aids maximize the retention of fillers and fibers, effectively remove pitch, and enable faster run speeds.

Papermaking and Retention Aids

In the initial stages of papermaking, pulp slurries are created, sent into a head box, and spread onto machine wires to start the drying process and form a paper web. During this final step, about 60% of the water in the paper slurry must be removed. Retention aids play a crucial role in determining paper quality and manufacturing efficiency. UCARFLOC™ is a line of high-viscosity polyethylene oxide retention aids designed for the papermaking industry. These aids work at relatively low concentrations to offer several benefits, as listed below:

 

• Increased first-pass retention of pulp, fiber, and commonly used fillers, such as kaolin clay and TiO₂
• Effluent becomes easier to filter and recycle
• Lower energy consumption required for steam roller drying
• Improved paper consistency and effective removal of pitch

These benefits arise from UCARFLOC™ retention aids’ ability to flocculate fine particles in the pulp slurry. For more details on how polymers like UCARFLOC™ perform flocculation, check out this article. 

How UCARFLOC™ Retention Aids Improve Modern Papermaking Processes

Maximizing the retention of pulp, fines, and fillers is crucial in the initial papermaking process. This leads to stronger paper webs, prevents visual and physical defects, and produces process water that is easier to filter and reuse. In recent years, paper mills have adopted new trends that require highly functional retention aids to address emerging challenges.

 

The data below demonstrate how effectively UCARFLOC™ enhances the first-pass retention of fillers such as clay and titanium oxide. The paper furnished in this study comprised 75% refined mechanical pulp and 25% semibleached kraft pulp. This increased retention resulted in finished paper sheets with higher opacity and brightness. Other commonly used fillers, such as sodium aluminum silicate and calcined clay, were also effectively retained using UCARFLOC™ retention aids in combination with phenolic resin enhancers.

 Effect of UCARFLOC™ on First-Pass Retention of Fillers Using UCARFLOC™

Paper mills can save energy using UCARFLOC™ retention aids to efficiently remove water from the paper web before the steam roller drying process. The following graph shows how UCARFLOC™ reduces the amount of steam needed to fully dry the paper later in the process.

  Effect of UCARFLOC™ on Steam Consumption

UCARFLOC™ is also highly effective at removing pitch from drainage effluent. A study using wastewater samples from newsprint mills determined the minimum concentration needed to remove pitch. In these samples, pitch was completely removed using a small amount of UCARFLOC™, ranging from 5 to 10 ppm.

 

*ND = none detected (<0.02 g/L)

UCARFLOC™ Versus Other Retention Aids

Typically, polyacrylamides (PAMs) or polyethylene imines (PEIs) are used as retention aids in papermaking. However, as cationic polymers, they have disadvantages when flocculating suspensions with high concentrations of anionic particles. In contrast, UCARFLOC™ retention aids are nonionic polymers that remain effective in highly anionic suspensions and across a wide range of pH levels. Additionally, UCARFLOC™ is extremely effective at relatively low concentrations. The following chart compares the flocculating efficacy of UCARFLOC™ versus PAMs, showing that UCARFLOC™ is better at retaining kaolin clay and reducing turbidity, even at less than half the concentration of cationic PAM.

Comparison of UCARFLOC™ Versus PAMs on Kaolin Clay Fillers

Summary

Rising pulp costs have made it challenging for paper mills to remain cost-effective. Additionally, new trends involving higher filler usage, faster operating speeds, and improved water reuse introduce new efficiency challenges. UCARFLOC™ polymers are designed to meet these challenges by significantly increasing the retention of pulp, fillers, and fibers in the papermaking process, resulting in consistently higher-quality paper. Consequently, drainage effluent is easier to recycle, and energy costs are reduced due to less steam required for drying paper webs. UCARFLOC™ provides these benefits at lower concentrations than other flocculants, such as polyacrylamides, offering comparative cost savings.