BYK 消泡剂
Peter van Dam, BYK-Chemie, PGM Surface Additives
No Foam in Pure Water 在纯水中不稳泡
Peter van Dam, BYK-Chemie, PGM Surface Additives
Mechanisms of Foam Stabilization: 稳泡的机理：
• Spreading coefficient 扩散系数 S = F - int - D
• Defoamer: 消泡剂： E > 0 and S > 0
= Surface tension of fluid 流体的表面张力 int = Interfacial tension fluid/defoamer 流体/消泡剂的界面张力 D = Surface tension of defoamer 消泡剂的表面张力
Peter van Dam, BYK-Chemie, PGM Surface Additives
Foam Stabilization 稳泡
hydrophobic non-polar 憎水性 非极性
hydrophilic Polar 亲水性 极性
Surfactant 表面活性剂
Peter van Dam, BYK-Chemie, PGM Surface Additives
F
Peter van Dam, BYK-Chemie, PGM Surface Additives
Spreading of Defoamer 消泡剂的扩散
• Marking water surface with inert powder 在水中撒些粉体 • Adding one droplet of defoamer 加入一滴消泡剂
Peter van Dam, BYK-Chemie, PGM Surface Additives
Bubbles Rise to Surface* 气泡上升到表面
__ V~
V = Velocity of rise 上升的速度 r = Bubble radius 气泡的半径 = Viscosity of liquid 液体的粘度
Peter van Dam, BYK-Chemie, PGM Surface Additives
BYK-defoamer Classes for Aqueous Systems 水性体系中BYK消泡剂的分类 • Mineral oil defoamers 矿物油消泡剂 • Silicone defoamers 有机硅消泡剂 • Silicone-free polymeric defoamers 非有机硅聚合物消泡剂
Peter van Dam, BYK-Chemie, PGM Surface Additives
Disadvantages of Mineral Oil Defoamers* 矿物油消泡剂的缺点 - Unstable during storage of the paint/separation/syneresis 在油漆储存中不稳定，分离，脱水收缩 - VOC’s (<249°C) - Dirt pick-up 易沾污 - Sick Building Syndrome 室内空气综合症 - Gloss reduction in low PVC systems 在低PVC体系中降低光泽 - May contain aromatic solvents 可能含芳香族溶剂 - Sometimes Micro-Foam 会导致微泡 - Difficult to incorporate 难以加入 - Odour 有气味
Mode of action of hydrophobic particlesQ 憎水粒子的工作模式
-Synergy between hydrophobic particles and defoamer oil 憎水粒子和消泡剂油之间的协同作用 - Rough, structured particles are more efficient then ball shaped particles Chemistry: hydrophobic silica, polyurea , waxes, amides, metall salts Only used in water-borne systems 一般来说，结构型粒子比起球状粒子更高效率：憎水性有机硅，聚脲，蜡， 金属盐，只适用于水性体系
Electrostatic Repulsion 静电排斥
+ + + + +
+ + + + +
++ ++ ++ ++ ++
>10 nm
Peter van Dam, BYK-Chemie, PGM Surface Additives
Foam Stabilization by Surfactants 表面活性剂导致的稳泡
Gloss and semigloss paints 高光/半光涂料
Emulsion production 乳液产品
Emulsion Type 乳液类型
Rapid spreading 迅速扩散
Peter van Dam, BYK-Chemie, PGM Surface Additives
Spreading of Defoamer (Slow-motion)Q 消泡剂的扩散（慢动作回放）
Peter van Dam, BYK-Chemie, PGM Surface Additives
Defoamer 消泡剂
Public Seminar Peter van Dam, PGM Surface Additives
Content 目录 • What is foam - foam stabilization 什么是泡-稳泡
• Mode of action of defoamers 消泡剂的工作模式 • Defoamer classes 消泡剂的种类 • Defoamer test methods 选择消泡剂的测试方法
2 r
Peter van Dam, BYK-Chemie, PGM Surface Additives
Defoamers: mode of action 消泡剂的工作模式
Properties of a defoamer: 消泡剂的特性： • Low Surface Tension 低表面张力 • Good spreading ability 优异的扩散能力 • Insoluble/Incompatible in the surrounding medium 围绕在液体中但不溶解，不相容 silicones, mineral oils and certain polymers fullfill these criterias 有机硅，矿物油和某些聚合物可以符合这些标准
Optimum compatibility/ good emulsification:最优相容性/良好乳化
- Strong defoaming 强消泡力
- Good substrate wetting/ no cratering 良好底材润湿/无缩孔
Defoaming Through Hydrophobic Particles 通过憎水粒子消泡
Peter van Dam, BYK-Chemie, PGM Surface Additives
Incorporation/Emulsification of defoamers. 消泡剂的加入/乳化 Droplet size distribution* 消泡剂分布
Small 小
Defoamer
Paint
• Gibbs-Marangoni-Effect 吉布斯-马拉高尼-效应 • Formation of electrostatic/steric repulsing double layers 静电的形成 / 双层空间位阻 • Increase of surface/interfacial viscosity 增加表面 / 界面粘度 • Gasdiffusion 气体扩散 • Foam stabilization through solid particles 固体粒子引起的稳泡 • Influence of viscosity 粘度的影响
Defoamer
Paint
Defoamer
Paint
Large 大
Size 大小
Substrate 底材
Shear/ Time 剪切/时间
Shear/ Substrate 底材 Time 剪切/时间 Substrate 底材 Too incompatible/ poor emulsification:太相容/乳化不足 - Strong defoaming 强消泡力 - Poor substrate wetting/cratering 不能润湿底材/缩孔
Defoamer Droplet 消泡剂液滴
Hydrophobic Particle 憎水粒子
Foam lamella 泡膜
Destabilization due to high hydrophobicity and dewetting 由于高憎水性和反 润湿而不稳定
Peter van Dam, BYK-Chemie, PGM Surface Additives
Peter van Dam, BYK-Chemie, PGM Surface Additives
Mineral Oil Defoamers for Emulsion Paints and Plasters 为乳胶漆和抹灰设计的矿物油消泡剂
Interior paints Industrial Plasters Emulsions 内墙漆，抹灰 工业用乳液
