Regulatory and sustainability initiatives lead to improved polyaminopolyamide epichlorohydrin (PAE) wet-strength resins and paper products

Abstract

Polyaminopolyamide-epichlorohydrin (PAE) resins are the predominant commercial products used to manufacture wet-strengthened paper products for grades requiring wet-strength permanence. Since their development in the late 1950s, the first generation (G1) resins have proven to be one of the most cost-effective technologies available to provide wet strength to paper. Throughout the past three decades, regulatory directives and sustainability initiatives from various organizations have driven the development of cleaner and safer PAE resins and paper products. Early efforts in this area focused on improving worker safety and reducing the impact of PAE resins on the environment. These efforts led to the development of resins containing significantly reduced levels of 1,3-dichloro-2-propanol (1,3-DCP) and 3-monochloropropane-1,2-diol (3-MCPD), potentially carcinogenic byproducts formed during the manufacturing process of PAE resins. As the levels of these byproducts decreased, the environmental, health, and safety (EH&S) profile of PAE resins and paper products improved. Recent initiatives from major retailers are focusing on product ingredient transparency and quality, thus encouraging the development of safer product formulations while maintaining performance. PAE resin research over the past 20 years has been directed toward regulatory requirements to improve consumer safety and minimize exposure to potentially carcinogenic materials found in various paper products. One of the best known regulatory requirements is the recommendations of the German Federal Institute for Risk Assessment (BfR), which defines the levels of 1,3-DCP and 3-MCPD that can be extracted by water from various food contact grades of paper. These criteria led to the development of third generation (G3) products that contain very low levels of 1,3-DCP (typically <10 parts per million in the as-received/delivered resin). This paper outlines the PAE resin chemical contributors to adsorbable organic halogens and 3-MCPD in paper and provides recommendations for the use of each PAE resin product generation (G1, G1.5, G2, G2.5, and G3).

Polyamidoamine epichlorohydrin (PAAE) wet-strength agent: Generations, application, performance, and recyclability in paperboard and linerboard

“…Examples of paper grades that benefited from the early application of PAAE are tissue and towel products, followed by liquid packaging board, tea bag and currency. Today, although PAAE is used mainly in paper products and molded pulp products, studies have shown that it can be used to protect antibody bioactivity on paperbased bio diagnostics (Huang et al 2017;Crisp and Riehle 2018;Valencia et al 2020;Qin et al 2022;Astute Analytica 2023).…”

“…Next, the poly(aminoamide) reacts with epichlorohydrin between 20 to 40 °C to form a tertiary aminochlorohydrin. Lastly, the temperature is raised between 60 to 80 C to promote the cyclization of the aminochlorohydrin functionality to the azetidinium functionality (3-hydroxyazetidinium group), and the resulting product is further partially crosslinked to produce PAAE resin; sulfuric acid is generally used to quench the reaction (Espy 1990;Andreasson and Wågberg 2009;Crisp and Riehle 2018;Francolini et al 2023).…”

“…It is important to note that the cost of the resin also increased as its quality improved over time. Today, to improve the cost efficiency of PAAE resin application, manufacturers are trying to produce high solid content resins (more than 25% solid) to minimize transportation, which not only reduces freight cost but also reduces carbon footprint (Crisp and Riehle 2018;Winkel 2018). Private discussions with vendors have indicated that at least 2 more generations of PAAE are currently under development.…”

Analytik und Beurteilung von Papier aus Sicht der amtlichen Überwachung

“…6). [27] Von ähnlichen Ergebnissen wurde im bundesweiten Monitoring 2022 sowie im Überwachungsplan 2020 berichtet. [34,35] Von besonderem Interesse ist die Feststellung, dass insbesondere beschichtete Materialien hohe Überschreitungen im KWE aufweisen können.…”