润湿剂的原理和应用是什么?
Quick answer: A practical additive decision starts with the exact defect: foam, poor wetting, craters, haze, or instability. The best product is usually the one that solves that defect with the safest compatibility window.
I.润湿剂的概念
润湿剂分子结构的基本特征是分子的一端带有亲水基团(链段),另一端带有化学物质的疏水基团(链段)。一般来说,这意味着分子分别具有亲水性和疏水性。
当树脂是水基树脂时,我对润湿机理(主要是水基树脂)的理解如下:
机理:当水性树脂涂覆在基材表面时,一部分润湿剂位于涂层底部,与被润湿表面接触,亲油链段吸附在固体表面,亲水基团向外伸入水中。水与基材的接触变成水与润湿剂亲水基团的接触,形成以润湿剂为中间层的夹层结构。使水相更易扩散,从而达到润湿的目的。另一部分润湿剂,存在于液体表面,其亲水基团伸向液体中的水,疏水基团暴露在空气中,形成单分子层,降低了涂料的表面张力,促使涂料更好地润湿基材,从而达到润湿的目的。
第二,液体润湿性能如何
润湿性能是衡量液体物质与固体物质亲和力的指标。主要表现形式有:a、在固体表面的润湿性;b、在固体表面的铺展性;c、在固体表面的渗透性。
简单地说,润湿性能好的液体易于在固体表面铺展,易于渗透到固体表面的缝隙中。
三、影响液体润湿性能的内在因素
润湿性能是一种相对的表现形式,也就是说与液体和固体本身的特性有关,其中最重要的是液体和固体表面张力的相对大小。液体的表面张力越小,固体的表面张力越大,液体对固体的润湿性能就越好,液体就能很好地在固体表面铺展。
第四,测量液体润湿能力
液体润湿能力的大小可用液体在固体表面铺展时,形成的接触角θ来衡量。接触角θ越小,液体对固体的润湿性能越好,θ等于零时,润湿性能最佳。其中θ=90°是一个重要参数,因为θ90°时,液体不能再在固体表面自发扩散润湿。
接触角可按下式计算: cosθ= (γs-γsl)/γl
在哪里?
γs 是固体的表面张力。
γl 是液体的表面张力。
γsl 是液体和固体表面之间的界面张力。相对于 γs 和 γl 而言,γsl 非常小,在计算中有时可以忽略。
除了用接触角θ 来衡量润湿性能外,铺展系数还可以用来表示润湿能力的大小。对于一定体积的液体,它的物理意义可以体现在固体表面润湿面积上,用 cm2/g 表示。液体的润湿性能越好,润湿面积就越大。铺展系数用 S 表示,计算公式为S=γs-γsl-γl;当 S 大于零时,液体能自发地在固体表面润湿。
V.影响润湿能力的因素
1、被润湿液体和固体的化学结构和组成。主要影响表面张力的大小,影响润湿能力。
2、固体表面的粗糙程度。例如,θ90°时,表面粗糙度增大,接触角变大,难以润湿。
3、固体表面的污染程度。固体表面污染一般不利于润湿。所以涂装前应先对基材进行去污处理。
4、表面活性剂。在液体中加入表面活性剂可以有效降低表面张力,促进润湿。
5、温度对材料的表面张力有直接影响,在实际工作中应加以考虑。
第六,理论的应用
从上述基本理论可以得出结论,涂料能否对基材产生润湿效果取决于涂料的表面张力。当涂层的表面张力等于或小于固体基材的表面张力时,涂层就能在固体表面很好地铺展。
In practice, there is also a measure of the choice of wetting agent, and formulators often compare CHLUMIWE 3280 Wetting Agent 和 CHLUMIWE 3071 Wetting Agent when they need to reduce coating surface tension and improve substrate wetting.
VII.常见物质的表面张力表
| 材料 | 表面张力[mN/m{dyn/cm}]。 |
| 水 | 72.2 |
| 乙二醇 | 48.4 |
| 邻二甲苯 | 30 |
| 乙二醇单乙醚醋酸酯 | 28.7 |
| 醋酸正丁酯 | 25.2 |
| 罗辛 | 24 |
| 正丁醇 | 24.6 |
| 甲基异丁基酮 | 23.6 |
| 甲乙酮 | 24.6 |
| 三聚氰胺树脂(HMMM 型) | 58 |
| 环氧树脂(Epikote 828) | 45 |
| 聚甲基丙烯酸甲酯 | 41 |
| 65% 大豆油脂肪酸醇酸树脂 | 37 |
| 无油醇酸树脂 | 47 |
| Modaflow 匀染剂 | 32 |
| 马口铁(无涂层/有涂层) | 35~45 |
| 磷酸盐处理钢 | 40~45 |
| 铝质 | 37~45 |
| 醇酸树脂底漆 | 70 |
| 玻璃 | 70 |
| 聚合物 | Yc(达因/厘米) |
| 脲醛树脂 | 61 |
| 纤维素 | 45 |
| 聚丙烯腈 | 44 |
| 聚氧化乙烯 | 43 |
| 聚对苯二甲酸乙二醇酯 | 43 |
| 尼龙 66 | 42.5 |
| 尼龙 6 | 42 |
| 聚砜 | 41 |
| 聚甲基丙烯酸甲酯 | 40 |
| 聚偏二氯乙烯 | 40 |
| 聚氯乙烯 | 39 |
| 聚乙烯醇缩醛 | 38 |
| 氯磺化聚乙烯 | 37 |
| 聚醋酸乙烯酯 | 37 |
| 聚乙烯醇 | 37 |
| 聚苯乙烯 | 32.8 |
| 尼龙 1010 | 32 |
| 聚丁二烯(顺式) | 32 |
| 聚乙烯 | 31 |
| 聚氨酯 | 29 |
| 聚氯乙烯 | 28 |
| 聚乙烯醇缩丁醛 | 28 |
| 丁基橡胶 | 27 |
| 聚偏二氯乙烯 | 25 |
| 聚二甲基硅氧烷 | 24 |
| 聚三氟乙烯 | 22 |
| 硅橡胶 | 22 |
| 聚四氟乙烯 | 18.5 |
| 全氟丙烯 | 16.2 |
| 全氟辛基甲基丙烯酸酯 | 10.6 |
A practical selection checklist for wetting, leveling, and defoaming additives
Additive selection is usually most effective when the team defines the defect first and then screens compatibility, dosage range, and process stage. That is often much more reliable than choosing only by chemistry family or by a single dramatic lab result.
- Start from the defect, not the additive name: wetting loss, crater, microfoam, and instability often need different solutions even inside the same formula.
- Check compatibility at the intended dosage: the strongest additive can still be the wrong commercial choice if it narrows the process window too much.
- Review the stage of use: some products are most useful during grind, while others matter more during let-down, filling, or final application.
- Balance cure or film quality with defect control: the right additive fixes the problem without sacrificing adhesion, gloss, or appearance.
Recommended product references
- CHLUMIWE 3280: A strong wetting-agent reference for inks, coatings, and difficult substrate wetting.
- CHLUMIWE 3071: Useful when organosilicone wetting support is needed in a broad application screen.
- CHLUMIAG 3000: A practical leveling and anti-sticking reference in UV coating and ink-related systems.
- CHLUMIWE 3345: A practical wetting-and-leveling reference when broader surface control is needed.
FAQ for buyers and formulators
Why does an additive that looks powerful in a beaker sometimes fail in production?
Because shear, temperature, substrate, and the full formula can all change the way the additive performs under real process conditions.
Should the most aggressive additive always be preferred?
Not usually. The best additive is the one that solves the real defect while preserving the broadest safe operating window.