Лако-красочные материалы — производство

Gums are hydrophobic or hydrophilic polysaccharides derived from plants or microor­ganisms that upon dispersing in either hot or cold water produce viscous mixtures or solutions. Natural gums include plant exudates (gum arabic, gum ghatti, gum karaya, gum tragacanth), seed gums (guar gum, locust bean gum, tamarind), plant extracts (ara — binogalactan from larch; agar, algin, funoran from seaweed), and the extracellular micro­bial polysaccharides (xanthan gum, dextran). Gums are used for many industrial purposes, as shown in Table 7. In recent years, synthetic polymers and microbially pro­duced gums increasingly have replaced plant-derived gums.

Historically, several adhesives have been derived from natural carbohydrate polymers. In a few cases, such polymers have been utilized because of their own particular adhesive properties. However, natural carbohydrate polymers are usually used as modifiers for more costly synthetic resins, especially as thickeners, colloidal stabilizers, and flow controllers. Adhesive uses for natural gums include pressure — sensitive tape, denture adhesives, pharmaceutical tablet binders, household products, and label pastes [17].

II. CONCLUSIONS

Carbohydrates, in the form of polymers such as cellulose, starch, and natural gums, are available in large quantities, especially from plant sources. Each of these has potential for utilization as adhesives and in adhesive formulations. This has been true historically and will be increasingly true in the future as petroleum-derived polymeric materials become scarce and their prices rise. However, because the bonds formed by carbohydrate polymer adhesives are generally sensitive to water, future applications of these adhesives will increasingly depend on modifying the natural polymer to give components that can undergo further cross-linking to form water-insensitive bonds.