Paper coatings, starch derivatives

Binders. Paper-coating biaders are either polymers derived from aatural sources or syathetic polymers. The largest volume, aaturally derived biader is starch (qv) (99). Starch is provided ia derivatized form or unmodified form pead com starch is used predomiaanfly for the latter. Unmodified starch is solubilized by thermal conversion or enzyme conversion. The most common derivatized products are acetylated [9045-28-7] oxidized, and hydroxyethylated starches. 

Advantageously, the viscosity and the gelatinisation temperature are lower than that of native starch. Starch derivatives are used in the paper industry for coating and glues. 

EcoSynthetix markets EcoSphere biolatex binder dispersions as a replacement for petroleum-based styrene butadiene latex. EcoSphere biolatex binders are based on starch derived from crops such as com, potatoes, and tapioca. Although the product was originally developed for the paper coating industry, it can also be applied in the textile coating industry. EcoSynthetix also produces EcoMer , a biobased building block to synthesize waterborne sugar-acrylic adhesives and resins. 

Starch (qv) and starch derivatives have a number of applications in the food industry as viscosifiers, gelatinizers, fillers, and paste formers in the textile and paper industries for coatings, sizing agents, rheology modifiers, and pigment binders and in the medical area as surgical powders, absorbents, adhesives, and in pharmaceuticals. 

These changes led to steadily growing problems due to an increased content of so-called detrimental substances in the water loops. Detrimental substances stem from wood components such as resin or Hgnin derivates, from freshwater as humic acids, from broke and recovered paper as coating binders, glues and adhesives, from additives as fatty acids or siHcates, starch and others. Table 5.1 shows the composition and origin of detrimental substances in the process water (2). 

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