BYK浸润剂和流平剂.pdf

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1、ImprovementofLevelinginAutomotiveCoatings汽车涂料表面流平改善狄文兆广州，2012-05TableofContent内容•Definitionofsurfacetension表面张力定义•Surfaceactivematerials:SiliconesandAcrylates表面活性物质：有机硅和丙烯酸•Howtoeliminatecommonpaintdefects如何消除常见涂料缺陷•Siliconesurfactantsforwater–basedsystems用于水性的有机硅活性剂CommonPa

2、intSurfaceDefects常见涂料表面缺陷•Poorflowandleveling差的流动与流平•Insufficientsubstratewetting不足的底材润湿•Foamstabilization稳泡•Oversprayacceptance漆雾接受性•Craters缩孔...areallsurfacetensionrelatedphenomena所有以上现象都与表面张力有关Surfacetension表面张力•Moleculesinliquidshaveahighmobility(insolids,themoleculesare

3、fixed)分子在液态下有很高的活动性•Inbetweenthemoleculestherearecohesiveforces分子之间有内聚力•Thehigherthesecohesiveforcesare,thehigherthesurfacetensionwillbe内聚力越高，，其表面张力越大，其表面张力越大Water(polar)水:73mN/m=strongcohesiveforces内聚力强Hydrocarbons(non-polar)烃类(非极性):23mN/m=nocohesiveforces无内聚力Liquidsstrivet

4、ominimizetheirsurfacearea(lowestenergystate)andtendtoformsphericaldroplets液体总是要将其表面积最小化(最低能量状态)并趋于形成球状液滴Surfacetension表面张力Gas气体LiquidWithinaliquid,thecohesiveforces液体compensateeachotherandthereisnoresultingdirectedforce在液体内部，内聚力相互抵消，处于力平衡状态Intheliquid/gasinterface,thecohesiv

5、eforcesaredirectedinwardsandside-wards,resultinginacontractingforceatthisinterfaceandleadingtothesphericalformobserved在液/气界面，内聚力指向内里和侧面，在其界面产生向内收缩的力，导致了球状的形成InterfacialTension界面张力Betweenaliquidandasolidthereareadhesiveforces,leadingtospreading.Thecohesiveforceswithintheliqui

6、darecounteractingthisandleadtoretraction.液固态之间有附着力，使其扩散，而液体内部的内聚力与之相反，使其回缩Liquid液体adhesiveforcecohesiveforcesadhesiveforce附着力内聚力附着力Solid固体Spreading:workofadhesion>workofcohesion扩散：附着力的功>内聚力的功InterfacialTension界面张力σσσliquidLiquid液体γγγsolid/liquidθθθσσσsolidσσσliquid•cosθθθSol

7、id固体σσσ=surfacetensionofsolid固体表面张力=γγγsolidsolid/gasσσσ=surfacetensionofliquid液体表面张力=γγγliquidliquid/gasγγγ=interfacialtensionbetweensolidandliquid液/固界面张力solid/liquidθθθ=contactangle接触角Atequilibrium达到平衡:σσσ=σσσ•cosθθθ+γγγsolidliquidliquid/solidObjectiveswhenformulatingcoati

8、ngs配制涂料的目的-goodflowandlevelling好的流动和流平-sufficientsubstratewetting充分的底材润湿-no