Starch
Also: starch, cationic starch
A polysaccharide used as internal strength additive, surface sizing polymer, and adhesive in coatings and corrugated bonding.
Starch is the single most-used chemical in papermaking after pigments. As internal strength additive (cationic starch), it bridges anionic fibers and fines to boost tensile and z-direction strength. As surface size, it forms a strengthening film on the dry sheet. As corrugating adhesive, it bonds the flute tips to the liners.
Starch origin varies by region: corn in North America, wheat in Europe, tapioca in Asia. Cationic starches are chemically modified to carry positive charge, which makes them adhere to cellulose fibers.
Related
- Sizing. The treatment that makes paper resistant to water and aqueous inks. Internal sizing is added to the furnish; surface sizing is applied to the dry sheet.
- Corrugated board. A sandwich of paper liners bonded to a fluted medium, used to make shipping boxes. Single, double, or triple wall configurations are standard.