rsisindependentofatmosphericinfluences.b.onditions.eptablelevelofdrying.mendtheuseofsuchdryers.c.VacuumdriersVacuumdriersareforeconomicalreasonsnormallyusedonlyinlaboratories.Invacuum,heatenergyistransferredalmostexclusivelybyradiation.Thisresultsinalongheatingtime.mendeddryingtimeistherefore50%-mendeddryingtimeinTable2.3.d.DegassingTheuseofdegassingunitsoninjectionmouldingmachinesis,withthecurrentstateoftheart,notafullyequivalentalternativetopre-drying.ThemainreasonforthisistheCRASTINandRYNITEhydro-liticaldegradationsofthepolymermeltuntilitreachestheventport.e.ounttherelativeshortmoisture®absorptiontimeofpolyester(especiallyRYNITEPET)mendedtousedryedairintheconveyingsystem.onditions.®®80°C0,1100°C120°C00246Dryingtime,hFig.2.4CRASTIN®PBTneverreaches0,04%moisturewhendriedat80°C0,2Moisture,6
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