Лако-красочные материалы — производство

Non-reactive polyamide (thermoplastic) resins are higher MW (up to 10,000 g/mol) condensation products of dimer fatty acids and diamines. Such resins are important binders for liquid inks. In the synthesis of these resins, both dibasic acid and diamine components are blended at medium temperatures and reacted until the water of reaction can be distilled off. They are solid umber colored products

marketed in different grades that differ in their MW and softening points (typically 90 to 150 °C).

The grades with MW above 4000 g/mol are soluble in aromatic hydrocarbons and higher alcohols but alcohol/hydrocarbon blends are more commonly used. They are frequently used with nitrocellu­lose binders too. The lower MW grades (<4000 g/mol) have impro­ved alcohol solubility and better compatibility with nitrocellulose. They are also compatible with such other binders used in printing inks as shellac, rosin, and maleic, phenolic and ketonic resins. The flexographic and gravure inks developed using these binders con­fer excellent adhesion to treated polyolefins, polystyrene and films coated with polyvinylidene chloride or similar difficult substrates. High gloss, heat sealability, fast solvent release and clean printing are among the important characteristics of these binders along with their good resistance to fats and greases. They are frequently used in overprint varnishes to provide scratch resistance. Other impor­tant uses for thermoplastic polyamides are as hot-melt adhesives and heat-seal coatings. They also find some applications in ther­moplastic powder coatings. Polyamides manufactured from omega — aminoundecanoic acid are used in thermoplastic powder coatings suitable for fluidized-bed applications. Some products derived by reacting polyamide resins with alkyd resins are used as thixotropic agents for solventbased coatings.