hydrophobing-agents

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1、TECHNICALBACKGROUND/HYDROPHOBINGAGENTS98HydrophobingAgentsTEGO®PhobeTECHNICALBACKGROUND/HYDROPHOBINGAGENTS99Becauseoftheirporeandcapillarystructure,mineralbuildingmaterialsabsorbmoistureoncontactwithwater.Theabsorbedwateroftenresultsinvisibledamageandisalsoacarrierforharmfulsub

2、stances.Furthermoreitactsasareactionmediumfordestruc-tivephysical,chemicalandbiologicalprocesseswhicharedeleterioustostructures,disfigureexternalwallsandseverelyimpairtheirfunction.Howeverwithappropriatemeasures,surfacesexposedtotheweathercanbemadewater-repellent.Figure1:Inadeq

3、uatepermeabilitytowaterresultsindamagetofacades.Sinceancienttimes,coatingshavebeenBreathablesilicatepaintsareequallyWhatishydrophobicity?consideredeffectiveprotectionforlackinginprovidinglastingprotectionbuildings.ForsuchcoatingstobebecausetheirhighwateruptakecanIncoatingstechn

4、ology,asubstratedurable,theyshouldabsorbaslittlerapidlyleadtodamage.Onlyhydrophob-surfaceisdescribedashydrophobicorwateraspossiblebutalsoexhibitgoodingsubstances,whichcanbeusedinwater-repellentifitisnot(ornotfully)permeabilitytowatervapor.paintsandasimpregnatingagentsandwettedb

5、ydropsofwateronit.Anim-primers,offeroptimumprotectionandportantparametercharacterizinghy-Systemswithahighbindercontentandenablethemanufactureofsystemssuchdrophobicityisthecontactangle.ItaPVC(pigmentvolumeconcentration)assiliconeresinandhydrophobedsili-canbedeterminedusingdropl

6、etsoflessthan50%arethemostfrequentlycateexteriorpaintswhichbothbreathewaterofconstantvolumeappliedtotheusedasexteriorpaints.Becauseoftheirandarewater-repellent.surface(fig.2andvideo”Measurementverylowpermeabilitytowatervapor,ofcontactangle“).blistersarefrequentlyformedandthecoa

7、tingspalls(fig.1).Particularlyhighcontactanglesarefoundforpolyfluorocarbonandsilicone-treated,highlywater-repellentsurfaces.Thecontactanglesbetweenwaterandsuchsurfacesarebetween140°and160°.Contactanglesaremeasuredusinganinstrumentwhichautomaticallyde-terminesthetangentsatthesub

8、strate/liquid/airinterface.Interpretationofthemeasured