BYK浸润剂和流平剂

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Improvement of Leveling in Automotive Coatings 汽车涂料表面流平改善狄文兆 广州， 2012-05

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Table of Content 内容 Definition of surface tension 表面张力定义 Surface active materials: Silicones and Acrylates 表面活性物质：有机硅和丙烯酸 How to eliminate common paint defects 如何消除常见涂料缺陷 Silicone surfactants for water–based systems 用于水性的有机硅活性剂

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Common Paint Surface Defects 常见涂料表面缺陷 Poor flow and leveling 差的流动与流平 Insufficient substrate wetting 不足的底材润湿 Foam stabilization 稳泡 Overspray acceptance 漆雾接受性 Craters 缩孔...are all surface tension related phenomena所有以上现象都与表面张力有关

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Surface tension 表面张力 Molecules in liquids have a high mobility (in solids, the molecules are fixed)分子在液态下有很高的活动性 In between the molecules there are cohesive forces 分子之间有内聚力 The higher these cohesive forces are, the higher the surface tension will be 内聚力越高， 内聚力越高，其表面张力越大 Water(polar)水:73 mN/m = strong cohesive forces内聚力强 Hydrocarbons (non-polar)烃类(非极性):23 mN/m = no cohesive forces 无内聚力 Liquids strive to minimize their surface area (lowest energy state) and tend to form spherical droplets 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

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Surface tension 表面张力Gas 气体 Within a liquid, the cohesive forces compensate each other and there is no resulting directed force 在液体内部，内聚力相互抵消，处 于力平衡状态 Liquid 液体In the liquid / gas interface, the cohesive forces are directed inwards and sidewards, resulting in a contracting force at this interface and leading to the spherical form observed 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

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Interfacial Tension 界面张力Between a liquid and a solid there are adhesive forces, leading to spreading. The cohesive forces within the liquid are counteracting this and lead to retraction. 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 adhesive force 附着力 cohesive forces 内聚力 Solid固体 adhesive force 附着力Spreading: work of adhesion > work of cohesion 扩散：附着力的功 > 内聚力的功

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Interfacial Tension 界面张力σliquid Liquid 液体 θσliquid cos θγsolid/liquid Solid固体σsolidσsolid σliquid= surface tension of solid固体表面张力 = γsolid/gas = surface tension of liquid液体表面张力 = γliquid/gasγsolid/liquid = interfacial tension between solid and liquid液/固界面张力 θ = contact angle接触角 σsolid = σliquid cos θ + γliquid/solidAt equilibrium达到平衡:

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Objectives when formulating coatings 配制涂料的目的- good flow and levelling 好的流动和流平 - sufficient substrate wetting 充分的底材润湿 - no crater 没有缩孔 - are directly related to the surface tension of this coating 这些都与涂料的表面张力有直接联系 - organic modified silicones and acrylates influence the surface tension in such a way to improve these properties 有机改性有机硅和丙烯酸酯通过影响表面张力来 改善其性能

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Typical surface tensions 典型的表面张力Solvents 溶剂 80 70 mN/m 60 50 Water 水Resins 树脂Subtrates 底材Melamine resin 氨基树脂 water-borne 水性Phosphatized steel 磷化钢材 Wood 木材40 30 20 Xylene 二甲苯 white spirit 溶剂油 Alkyd resin 醇酸树脂 Acrylate 丙烯酸Untreated steel 未处理钢材 SMC-Polyester聚酯 Polypropylene聚丙烯

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Surface Active Materials 表面活性物质Silicones and Acrylates are surface active materials 有机硅和丙烯酸是表面活性物质 Orientate to interfaces 定向的界面 Liquid / air 液 / 气 Liquid / substrate 液体 / 底材Orientation to interface liquid / air prevents surface tension differences 定向到液 / 气界面防止表面张力不同

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Silicones And Acrylates: Working Mechanism 有机硅和丙烯酸： 作用机理 Silicones: 有机硅 Orientation to interfaces mainly due highly active surface orientation 定向在界面由于高的表面活性定向Acrylates: 丙烯酸 Orientation to interfaces mainly due to controlled incompatibility 定向在界面由于受控的不相容性

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有机硅: 定向迁移到界面Silicones: Orientation to InterfacesH3CCH3 H3C SiCH3 SiH3CCH3 SiH3CCH3 H3C SiCH3 SiH3CCH3 SiH3CCH3 H3C SiCH3 SiH3CCH3 Si涂膜CH3 H3C Si CH3 H3C Si CH3 H3C Si CH3 H3C SiMarch 2011, Page 12Paint filmH3C Si CH3 H3C Si CH3 H3C Si CH3 H3C Si CH3 H3C SiAdditives For UV- CoatingsCH3底材SubstrateGeneral Industrial Coatings

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有机硅: 调节表面张力的降低Silicones: Adjustment of Surface Tension ReductionCH3 (CH3)3 Si O Si OCH3 Si O Si (CH3)3Non–polar烷基Organic ModificationAlkylmN/m 21 26 32烷基有机改性极性PolarCH3 CH2CH3 (CH2)9CH3AlkylxyMarch 2011, Page 13General Industrial CoatingsAdditives For UV- Coatings

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Silicones: Recommended Areas of Usage 有机硅： 推荐应用于 For improvement of 改善 Substrate wetting 底材润湿 Surface slip 表面滑爽 Crater resistance 抗缩孔（鱼眼） Adjustment of flow and leveling 调节流动与流平 ........................different types of silicones are required 需要不同的有机硅类型

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Silicones: Surface Tension Reduction 有机硅： 表面张力降低mN/m30 29 28 27 26 25 BYK® -320/-315 BYK® -331 BYK® -300 BYK® -310 BYK® -306/-333 Dosage level 用量

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Substrate Wetting: Impact of Surface Tension 表面张力对底材润湿的影响ST paint > ST substrateST paint < ST substrate

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Surface Slip 滑爽High amount of Dimethyl groups = high increase of surface slip 越高的二甲基基团含量 = 增加表面滑爽

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Craters 缩孔Overspray or dust particle with lower surface tension Paint with higher surface tension 高表面张力油漆低表面张力的漆雾或尘粒

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Silicones 有机硅 To improve 改善 Substrate wetting 底材润湿 Surface slip 表面滑爽 Crater resistance 抗缩孔.... silicones with strong influence on surface tension reduction are required 需要强降低表面张力类型的有机硅

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Leveling: Definition 流平：定义Leveling 流平

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Leveling 流平What controls leveling? 什么影响流平 Rheology 流变性能 Time 流平时间 Surface tension 表面张力How to improve leveling? 如何改善流平 Deflocculating wetting & dispersing additives (rheology in pigmented systems) 解絮凝的润湿分散剂（有颜料体系） Solvents (time) 溶剂（流平时间） Resins, additives (surface tension) 树脂，助剂 （表面张力）

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