Simplifying Wet-End Chemistry

Papermakers are under pressure to do more with less: use more recycled fiber, manage fluctuating furnish quality, improve machine efficiency and produce stronger paper at lower basis weights. At the same time, mills are expected to reduce energy consumption, simplify operations and support more sustainable production.

Traditionally, meeting these demands has required a complex combination of additives—starch, dry strength agents, retention aids, drainage aids and charge control agents. Managing multiple chemistries, and the interactions between them, can add cost, complexity and variability to papermaking operations.

Solenis introduced Xelorex™ paper performance additives in 2013 to help mills address these challenges. Built around a family of unique polyvinylamine (PVAm) polymers, Xelorex can perform several functions simultaneously. Instead of relying on multiple additives, mills can use Xelorex polymers to help improve strength, retention, drainage and charge control through one integrated solution. However, first-generation polymers were shipped in liquid form to papermaking sites, increasing transportation requirements and associated carbon emissions.

With Xelorex™ Plus paper performance additives, Solenis has advanced the technology further. Xelorex Plus delivers the multifunctional performance benefits of PVAm chemistry in an easy-to-ship dry powder formulation, reducing transportation demands while enabling on-site generation of a customized liquid solution.

To understand the value of Xelorex Plus, it helps to look at how PVAm chemistry evolved from a strength solution into a multifunctional wet-end platform.

Starting with Strength

Researchers began exploring the effectiveness of polyvinylamine polymers in the mid-1970s. Early work demonstrated that this simple polymer, which contains primary amine groups (nitrogen-containing functional groups), could significantly improve paper wet strength without the same degree of formaldehyde chemistry associated with traditional wet‑strength resins. How PVAm increased wet strength remained elusive at first, but scientists eventually determined the mechanism of action, learning that PVAm contributed to fiber-fiber bonding in three ways:

1. Electrostatic attraction: The primary amine groups in PVAm chains become strongly positively charged during the hydrolysis process. Pulp fibers and fines are naturally negatively charged. Positive PVAm sites on one fiber are attracted to negative sites on adjacent fibers.
2. Hydrogen bonding: PVAm’s amine groups can form multiple hydrogen bonds with cellulose hydroxyl groups, reinforcing the fiber joints.
3. Covalent bonding: Under certain conditions, PVAm can form very stable bonds with appropriately functionalized cellulose surfaces.

Solenis scientists designed Xelorex around these strength characteristics. By forming strong, multidimensional bonds with fibers and fines, Xelorex polymers enhanced fiber-to-fiber bonding and increased initial wet web strength (IWWS). Stronger wet webs helped reduce sheet breaks during production, improving machine productivity and operational stability. For mills, that can mean stronger paper, the ability to produce higher-performance grades, higher machine speeds, improved runnability and reduced energy consumption.

A Multifunctional Approach to Paper Performance

Building on early PVAm research, scientists learned that they could fine-tune the polymer structure and broaden its functionality. For example, they could substitute additional cationic or anionic groups for amine groups, changing the molecule’s charge density. They could also introduce hydrophilic or hydrophobic groups to modify interactions with fillers and fines or adjust solubility. This expanded PVAm from a single-purpose resin to a family of tailored wet-end tools, making it possible for mills to reduce or eliminate selected wet-end additives, simplify their chemical programs and lower overall chemical consumption.

That broader functionality became central to Xelorex. Building on its strength profile, Solenis scientists engineered the polymers to improve formation, retention and drainage while helping reduce sizing consumption. In many applications, Xelorex additives can reduce or eliminate the need for starch, dry strength, drainage and retention aids, contaminant control agents, sizing agents and charge control additives.

Xelorex Plus builds on this multifunctional approach while adding greater customization. Using Solenis’ proprietary on-site generators, papermakers can produce a PVAm solution tailored to their grades and operating conditions, whether they make packaging, graphic and specialty papers or tissue and towel grades.

The Xelorex Plus process starts with a dry PVAm polymer that can be stored shelf-stable for several months. Using the on-site generator, the polymer is converted into a liquid product with properties customized to the mill’s specific needs and application requirements. The result is a simpler wet-end program, with one multifunctional polymer replacing or reducing several other chemistries and helping deliver:

• Lower overall additive consumption
• Fewer process variables to manage
• Reduced system deposition
• Improved machine cleanliness

This simplification can help mills target several cost drivers at once, from chemical consumption and process variability to machine downtime.

Supporting Sustainable Papermaking

Sustainability is now a central priority for the pulp and paper industry. Xelorex Plus supports more sustainable papermaking in several ways:

• By improving strength, Xelorex Plus can enable higher recycled fiber usage and help reduce reliance on virgin fiber.
• By improving formation, retention and drainage, it can support higher machine speeds and reduce energy consumption during papermaking.
• By replacing or reducing multiple chemistries, it can simplify a mill’s wet-end program and reduce the chemical burden in effluent.
• Because Xelorex Plus is shipped in dry form, it can cut transportation needs by up to 10x, helping lower freight costs and reduce associated CO₂

Innovation That Delivers Practical Results

Papermakers need solutions that improve product performance, simplify operations and support sustainability goals without adding complexity to the wet end.

Xelorex Plus shows how innovation in papermaking chemistry can help mills meet those needs—improving strength, efficiency and operational stability while reducing complexity, transportation demands and environmental impact.

Learn more about how our portfolio of strength additives can help improve your operational performance and support your sustainability goals.