11 сентября, 2015 
Pokraskin Polyurethane adhesives for plastics are available primarily in both single-component and two-component forms. They are very tough, flexible products with excellent peel strength and are also extremely versatile for the bonding of larger plastic components.
Many grades of polyurethanes are certainly adhesives and not just sealants and most automotive windscreens are now bonded in with a polyurethane-based adhesive. The excellent adhesion, durability and good flexibility are key properties. Note that most
automotive manufacturers will include a black strip at the periphery of the windshield and this strip is not only to improve the aesthetics of the bond where the black polyurethane might have extruded outside the joint but it also serves as a UV protection to the adhesive as polyurethanes generally have poor resistance to ultraviolet light.
Single-part polyurethanes rely on an atmospheric moisture cure and will release isocyanates during the cure cycle. Cure times are relatively slow with a skin-over time of about 20-30 minutes and complete cure in 3-7 days depending on the grade. The isocyanates can lead to health and safety concerns in the workplace as they would be classified as irritants and in some cases toxic.
Two-part polyurethanes still release isocyanates but the cure time is considerably improved. Two-component polyurethanes are the most common type used for plastics bonding, although primers are sometimes required to improve adhesion.
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