Standards For High-Quality Defoamer

A high-quality defoamer must meet the physical and chemical performance requirements of the application system. Generally speaking, when selecting a defoamer, the following requirements must be considered:

Strong defoaming ability. It can effectively eliminate foam with a very small amount.

(2) It has a lower surface tension than the defoaming system, meaning that the surface tension of the defoamer itself is lower.

(3) After the defoamer is added, it will not affect the basic performance of the defoamed system.

(4) It is insoluble in the defoaming system and is not easily solubilized by the surfactants in the system. If it becomes solubilized, it loses its defoaming ability and its capability to suppress foaming.

The surface balance should be good.

(6) It does not react with the defoamed medium, nor will it be decomposed or degraded by it, and has good chemical stability.

(7) It has good diffusivity and permeability, which means it has a positive diffusion coefficient in the foam medium.

Rapid spreading ability on the foam surface.

(8) The defoamer should have good heat resistance and not lose its effectiveness at high temperatures.

(9) With good gas solubility and permeability, it prevents gases from accumulating and disappearing from the foam, making the foam easy to eliminate.

(10) It has high physiological activity and safety in the defoaming system, and the defoamer itself should preferably be non-toxic, or at least a low-toxicity substance.

(11) Having low COD, BOD, and TOD values;

(12) Have good storage stability;

(13) It has a long-lasting defoaming effect; some defoamers can quickly eliminate foam but lose effectiveness over time.

The cost should be low.

(15) Does not increase the surface viscosity of the surfactant aqueous solution.

It is very difficult to achieve all the aforementioned requirements with a defoamer; one can only meet the main performance criteria of the system being defoamed. Each defoamer is only effective for a specific system or a few systems, and it is unrealistic to expect a single defoamer to achieve the defoaming purpose across all systems. Additionally, multiple different defoamers can be selected for the same foam system, which is why there are many varieties of defoamers available. Users must conduct experiments to select the most effective and economical defoamer. Currently, research on defoamers has garnered significant interest from many researchers, with over a hundred papers published annually, and new varieties and patents are emerging continuously.