Novel paper sizing agents from renewables. Part 3: Emulsion stability and hydrolysis behavior compared to conventional sizes

The hydrolytic stability and sizing behavior of a new paper sizing agent based on renewable vegetable oils (maleated sunflower oil, high oleic: MSOHO) was compared to two conventional alkenyl succinic anhydride (ASA) specimens, a commercial sample, and a reagent-grade ASA sample. At various pH conditions as well as upon addition of Ca2+ ions, MSOHO was more stable than both ASA samples. This superior stability of MSOHO was also supported by zeta potential measurements over 1 week. Whereas for sizing of paper higher dosages of MSOHO were needed to gain certain water repellency as compared to the ASA samples, the addition of alum had a pronounced positive effect on the sizing efficiency of MSOHO. The higher stability of MSOHO made it possible to size with an MSOHO-starch emulsion that was aged for one day at room temperature, when conventional ASA-starch emulsion had long lost any sizing efficiency.