16 декабря, 2015 
Pokraskin The ‘open time’ of an adhesive is the time it can remain on an adherend before the joint needs to be closed. For epoxies this would typically be about 50% of the fixture time as any longer time could result in the adhesive not wetting and thus not adhering properly to the second substrate.
UV adhesives have an almost infinite ‘open time’ although exposure to workshop light and daylight can initiate slow polymerisation.
Cyanoacrylates would normally have a relatively short open time as they are very sensitive to surface moisture and to a lesser extent atmospheric moisture. In most cyanoacrylate applications, the joint should be closed within a few seconds and certainly not more than a few minutes.
Room-temperature-vulcanising silicone adhesives will ‘skin over’ in about 10 minutes and so the joint should be closed within a five-minute period to ensure that full wetting and therefore adhesion takes place.
For fully automatic dispensing systems, this means that some consideration must be made to ensure that the joint is closed within the specified time.
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