Surfactant Migration Impact on Dynamic Surface Tension in Hardwood Stock
Residual surfactant migration in hardwood stock depresses dynamic surface tension below forty millinewtons per meter, triggering jetting print defects.
Alkylphenol Ethoxylates
Chemical Composition
Non-ionic surfactants function as emulsifiers and wetting agents during the processing of pulp and the application of coatings. Manufacturers utilize alkylphenol ethoxylates to stabilize aqueous dispersions of pigments and binders in paper coatings. These compounds consist of a branched alkyl chain attached to a phenol ring that has been ethoxylated.
While effective at reducing surface tension, these substances persist in wastewater systems.
Surfactant Application
Wetting performance determines how effectively a coating spreads across the base sheet surface. Using alkylphenol ethoxylates ensures that synthetic latex binders remain suspended without coagulating during the shear forces of high speed blade coating. The chemistry facilitates the penetration of sizing agents into the fibre matrix.
This process prevents surface defects such as pinholes or uneven absorption. Stable dispersions allow for a higher solids content in the mix, which reduces the energy needed for drying later in the line.
Regulatory Limit
Environmental restrictions target the degradation products of these molecules because they exhibit endocrine disrupting properties in aquatic organisms. Most voluntary certifications for food contact paper and sustainable forestry prohibit the intentional use of these surfactants in the mill. Limits typically sit at 100 parts per million for the sum of the most common variants.
Compliance requires testing via solvent extraction followed by chromatography.