An Application of Waxy Rice as the Paper Coating Binder.

Waxy rice is one of the major agricultural products in Asia. Its applications, however, have been limited only to the food products, and no literature reports could be found about its application to paper products. In view of its chemical composition containing almost all amylopectin, waxy rice starch should be applicable to the paper coatings. This report presents our research on the applicability of waxy rice as the paper coating binder. Experimental results indicate that waxy rice is applicable as the coating binder, since when applied using the same formulation, waxy rice provides similar paper coating properties as do corn starch and soy protein, the commonly used coating binders. The coating properties can even be enhanced using waxy rice after alkaline or acid treatments. Sodium hydroxide treatment results in improved picking resistance and gloss. And light hydrogen chloride treatment provides enhanced brightness and opacity. Three different types of waxy rice are studied, namely, long, short, and black waxy rice. Among them, short waxy rice performs the best as the coating binder. But after the alkaline treatments, long waxy rice yields better coating properties than either short or black waxy rice. Finally, the experimental results suggest that a critically diluted concentration should be practice with the acid treatment in order to maintain the picking resistance.