Cyanoacrylates ultraviolet

Anaerobic sealants Cyanoacrylates Ultraviolet-cured sealants Methyl methacrylate Metal and glass glues Epoxy diacrylates (vinyl resins) Acrylic dental bonding agents... 

Cyanoacrylates are not appropriate for the bonding of the steel parts of an automobile, because of the environments that the car will be exposed to. Those environments include such things as rain, variations in temperatnre, exposure to solvents (such as gasoline, oil, and windshield washer solntion), ozone, acid rain, salt spray, and ultraviolet light from the Sun. (A more appropriate adhesive for car parts would be an epoxy-based adhesive.) Another example of a special adhesive would be the one used to attach a new rearview mirror in an antomobile. Because the cured adhesive in this case will be exposed to wide variations in temperature and to an extremely large amonnt of nltraviolet fight from the Snn for prolonged periods of time, an adhesive formnlated specifically for these conditions should be used. 

Cyanoacrylate monomers are highly reactive compounds and will polymerize via anionic and/or free radical mechanisms. The anionic reaction route is by far predominant and can be initiated by even small amounts of a weak base such as water. Exposure to extended high temperatures, ultraviolet light, or heat in the presence of peroxides can cause free radical polymerization to be initiated. The extreme anionic reactivity of these monomers was unobserved by early workers, probably due to crude preparatory methods which resulted in very impure, overstabilized product. Early attempts to polymerize the monomers nearly always involved thermal methods. It was not until the early 1950s that Coover and Shearer of Eastman Kodak, using purer material stabilized with SO2 gas, discovered the unique polymerization and bonding characteristics of the cyanoacrylate monomers. 

Perhaps one of the most fundamental and key properties associated with the selection of the adhesive is to make sure that it bonds well to the two materials selected. Cyanoacrylates generally have good affinity to plastics and a good number of ultraviolet (UV) adhesive grades are also particularly suited for plastics, whilst other UV adhesives (with silane additives) are more suitable for glass - the product data sheet should be studied carefully to ensure compatibility with both adherends. Epoxies are good general-purpose products and can show excellent adhesion but are slower cure. 

While the overall rate of increase of adhesive consumption since 1950 has been high, the growth of certain types of products has been especially dramatic. Pressure sensitive and hot melt formulations have been very rapid gainers and anaerobic adhesives too have been strong performers in recent years. Specialty adhesives, including cyanoacrylates (the so-called instant glues) and ultraviolet radiation cured products have also been favorably received. 

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