Screening of low bubble deoiling surfactants

In the oil removal process of pre-plating treatment, a large amount of foam produced by stirring or blowing will interfere with the cleaning effect, 

such as excessive foam rising will lead to the overflow of the working fluid, which not only causes waste of materials, increases the cleaning cost, 

but also may produce stains on the surface of the cleaning raw materials, which brings inconvenience to the production. In addition, 

too much foam will hinder the washing of oil and slow down the precipitation and separation of dirt, and the discharge of oil remover due to 

too much foam will also increase environmental pollution.

Therefore, under the premise of ensuring the degreasing effect of the degreasing agent, the foaming ability of the degreasing agent should be 

as low as possible. At present, the main way to achieve the low foam of degreasing agent is to add defoamer to the cleaning agent, but there is often 

a problem that its defoamer ability is reduced with the progress of the degreasing process, and even some silicon-containing defoamer will appear in the 

degreasing process silica gel, silicon spots and so on. Another way to obtain the low foaming effect is to improve the oil removal efficiency of the surfactant 

and reduce the amount of surfactant to achieve the low foaming requirement by screening and combining the surfactant. Therefore, understanding more 

of the relationship between the structure, physical and chemical properties of the surfactants themselves and the oil removal effect, screening several low-foam 

surfactants suitable for metal surface oil removal, using the synergies and synergies between the surfactants, the combination of several surfactants, 

and obtaining the best low-bubble oil removal effect, is the direction and approach of metal oil removal research and development.

Comparison of properties of surfactants

The effects of surfactant permeability, emulsification, dispersion and foam on oil removal were analyzed in order to screen the structure and types of 

surfactants suitable for oil removal before electroplating.

The order of oil removal rate of non-ionic surfactants is: OP-10 > TX-10 > E-1310 > OP-7 > E-1307 > MOA-5 > MOA-9 > MOA-7 > MOA-3

The order of low foam properties of non-ionic surfactants is MOA-3 > MOA-5 > E-1310 > OP-10 > E-1307 > MOA-7 > MOA-9 > TX-10

The order of oil removal rate of anionic surfactants is FMES > AOS > LAB > SDS > RP98 > AES > SAS-60, and its low foam performance is RP-98 

> FMES > AES > AOS≈LAB≈SAS-60

In the screening process of surfactants for oil removal, the characteristics of low foam should be achieved as far as possible under the premise of ensuring the 

oil removal performance of surfactants. 6501 and Tween series non-ionic surfactants are not suitable as the main components of oil remover because of their 

poor performance in either foam or oil removal. Block polyether L-61 and L-64, isoctyl alcohol JFC, pan series, oil removal performance is general, 

although the use alone has the advantage of low foam, but with other non-low-foam surfactant compound, foam is not significantly reduced, 

so this product is not suitable for oil removal agent production.

Screening and mixing of surfactants: the performance of non-ionic surfactants is more suitable, comprehensive foam performance, penetration, dispersion performance,

non-ionic surfactants OP-10, TX-10, E-1310 and MOA-5 can be used as alternatives. The cost of OP-10 and TX-10 is moderate, and the oil removal effect is good, 

but there is a high COD value and damage to the environment. E-1310 has excellent overall performance, but it is the most expensive among non-ionic surfactants.

MOA-5 does not have the most prominent advantages, but the cost, application performance, environmental performance is more balanced. Although anionic 

surfactants have poor oil removal performance, they have no turbidity point limitation, good alkali resistance, and low product price. Under the premise of not 

weakening other application properties of oil remover, the use of appropriate anionic type for combination can reduce the cost of oil removal.