Лако-красочные материалы — производство

The original development of polyurethanes was relatively slow due to early competition from more favourable epoxy formulations. However, in the 1950s and 1960s work on surface coatings suggested that polyurethanes were capable of being formulated to achieve a wide variety of performance properties, some of which were appropriate to applications as adhesives. Nowadays uses are wide — ranging, taking advantage of strength in automotive panel bonding, through to flexibility and toughness required in shoe manufacture. Building and construction applications to date have been semi — or non-structural, for example in prefabricated building elements, roofing and flooring, and as movement joint sealants.

Urethanes are manufactured from iso-cyanates and it is the iso­cyanate groups which are capable of reacting with any material containing reactive hydrogen, to form urethane linkages. Thus linear chain molecules can be built up by reaction with water, amines or alcohols. A wide variety of formulations can result including elastomers, two part cross-linked urethanes, single part moisture curing products, hot melt and water borne urethanes. The 100% solids systems hold the most promise for structural bonding since they do not involve the loss of solvents or water during the cure process. Current applications include sandwich panel construction, and the bonding of polymer composites, metals and timber. The bonding of highly alkaline substrates such as concrete is not however advised.