CALEXIS® Wet Strength Efficiency with PAE

Papers required to function when exposed to water or wet environments need strength that is not achievable without some type of wet strength aid. This growing segment of consumer and industrial products such as tissue, towel, filter media like tea bags and coffee filters, labels and security papers all have special requirements for wet strength. Wet strength properties are adjusted to the end-user requirements of the grade, with some types needing temporary and lower wet strength, and other grades needing permanent and high wet strength.

Unlike internal sizing, which reduces the adsorption rate of water into the sheet as a route to managing strength during exposure to water, wet strength resins allow the sheet to adsorb water as intended during the end uses. The most common wet strength resins are cationic water-dispersible resins based on polyamide pichlorohydrin (PAE) or polyamideamine epichlorohydrin (PAAE).

CALEXIS® Wet End Strength Technology provides the tool for papermakers to optimize the use of wet strength resins to maximize both wet and dry strength performance properties. These custom-designed, water soluble, nature-based materials allow the highest levels of wet strength to be achieved with optimized wet strength resin dosage levels – saving materials and money.

Interacting with PAE. Cationic PAE wet strength resins are adsorbed to the cellulose fiber through electrostatic charges during papermaking. CALEXIS, a hydrated anionic polymer compatible with cellulose fibers, achieves higher levels of adsorption of PAE. A mechanism of “bridging” or “layering” formed between CALEXIS+PAE permits the wet strength network to reach farther from one fiber to another to create wet strength bonds. The layered network of CALEXIS+PAE on the fiber surface allows greater contact area at fiber crossings and higher bonded surfaces.