Quick answer: A practical coating formulation choice starts with the application environment, then checks film formation, adhesion, appearance, and process stability under real production conditions.
涂料溶剂的选择条件是什么?
气相清洗时,工件在溶剂蒸汽层中进行清洗、漂洗和干燥,工件不会受到二次污染,因此可以达到很高的清洁度。但如果管理不善、操作不当,往往会出现溶剂损耗过大的问题,增加使用成本。下面就溶剂损耗过多(尤其是低沸点溶剂)的原因做一些分析,并提出一些解决方案
(1)洗衣机的位置摆放不当,有强烈的空气对流,导致溶剂挥发过多
解决方案:清洗机应避免放置在门口、窗口等有穿堂风的地方,以及电风扇、空调的出风口。
(2) 净化器上部自由区域(从蒸汽表面到罐顶的距离)空间不足,溶剂蒸汽受周围气流影响而逸出。
解决方案如下
①这是一个罐体结构设计问题,罐体设计时,应注意汽面到罐顶的距离与罐体宽度的比值应大于 75%,使用低沸点、易挥发的溶剂和价格较贵的 HFC-4310 溶剂时,比值应提高到 1.2~2.0;汽面的位置可从冷凝盘管的中间或略低于冷凝盘管的位置考虑。
也可采用双冷凝管、双冷凝温度,上部冷凝管温度控制在-29OC,下部工作冷凝盘管温度可控制在 4 OC 左右。
(3) 清洗槽的宽度不宜过宽。
(3) 蒸汽表面过高,冷凝能力不足,使溶剂蒸汽逸出过多。
解决方案如下
检查制冷系统是否正常工作,及时排除故障。
如采用水冷却,应检查冷却水出口处的温度,对沸点在 45 至 50 OC 之间的溶剂,排水口处的水温应控制在不超过 21 OC;对沸点在 45 OC 以下的溶剂,排水口处的水温应控制在不超过 16 OC。
(4) 蒸汽表面失控,大量溶剂蒸汽逸出
解决方案如下
正常运行时,蒸气面应控制在冷凝盘管的中部或略低一些,可通过调节冰箱的蒸气温度或调节冷却水的温度和流量来控制。
检查设备的温度保护装置,当蒸汽面过高时(如制冷系统故障),应能自动切断电源,停止加热。
(5) 工件放置不当,溶剂随工件流出
解决方法:工件清洗时,应使凹面向下,这样溶剂才能最大限度地流出,而不会在凹面积聚。
(6)工件在槽内移动过快,使溶剂蒸汽逸出
解决方法:工件在清洗槽内上下或左右移动时,速度不能太快,应保持蒸汽层的稳定,一般工件移动速度应小于 50mm/s。
(7) 蒸汽层高度不够或干燥时间不足,导致溶剂被工件带出。
解决方案如下
蒸汽层应足够高,以使工件在槽体内运动,工件不露出蒸汽层。
工件在汽蒸层中漂洗停留的时间,应在表面无凝露无溶剂滴落之前结束,工件离开汽蒸面后,在冷冻干燥区再作短暂停留,以便彻底干燥。
(8)喷淋冲洗不当,增加溶剂飞溅损失。
解决方案如下:
喷淋清洗时,喷枪位置应低于蒸汽表面 150mm,并应向下喷淋。
喷淋压力不宜过高,一般小于 0.1MPa;喷淋液流,以多股细线流喷淋为好,喷淋会增加飞溅损失。
(3)在没有形成稳定蒸汽的表面不进行喷洗。
(9) 操作程序不当,增加了溶剂的蒸发损耗
解决方案如下
① 清洗水箱加热前,应先接通冷却水或开启冷却器。
工作完成后,先关闭加热器,但冷却水不停或冷却器不停,直到蒸汽层完全消失,溶剂温度接近室温,再停水或关盖。
低温控制清洗机内的溶剂温度,保持溶剂温度低于周围环境温度,以减少溶剂蒸发到停止工作时的损耗。
(10) 使用和储存不当,导致溶剂流失
解决方案如下
① 洗衣机不使用时,应加盖密封;
长期不使用时,应将溶剂释放出来,存放在密闭的桶中;
③ 清洗机要有专人负责维护,管道接头、水泵、出料阀、过滤器等要经常检查有无渗漏。
How buyers usually evaluate coating and paint topics
In conventional coating work, technical buyers usually move fastest when they define the film-performance target first and then review rheology, substrate compatibility, additives, and long-term durability as one system instead of isolated tweaks.
- Start from the application scenario: furniture, powder coating, industrial paint, and waterborne systems often reward different formulation priorities.
- Check surface quality and process stability together: leveling, wetting, foam control, and drying often interact strongly.
- Review the film after full cure or drying: adhesion, hardness, weatherability, and color stability usually decide the commercial result.
- Use targeted additive screening: wetting, leveling, defoaming, and wear-resistance additives work best when the defect is clearly defined.
Recommended product references
- CHLUMIAF 094: A balanced defoamer reference for waterborne coatings and many general foam-control screens.
- CHLUMIAF 3062: Useful when printing-ink and UV-ink compatibility matter in the defoaming screen.
- CHLUMIAF 3037: A stronger process-defoaming option when persistent foam survives harsher conditions.
- CHLUMIWE 3280: A strong wetting-agent reference for inks, coatings, and difficult substrate wetting.
FAQ for buyers and formulators
Why can a coating with good initial appearance still fail later?
Because many failures show up only after full cure, storage, or service exposure, when adhesion, flexibility, or weatherability becomes the limiting factor.
Should coating additives be chosen one by one outside the full formula?
It is usually safer to screen them inside the real formula because resin choice, pigments, and the rest of the additive package can change the result.