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topic 4344

Defoaming agent for degreaser tank


A discussion started in 2000 but continuing through 2018

2000

Q. We are in the business of various industrial degreasing chemicals in India.

The degreasing chemicals containing highly alkaline powdered builder even without having any surfactants produces heavy foaming during continuous spray or electrolytic degreasing of cold rolled sheets. The cold rolled sheets contain semi synthetic rolling oil/coolant oil emulsion (having SAP value 180-190). We are using silicone defoamer but it hardly matters to defoam heavy foaming. can any body recommend any suitable reason for this heavy foaming?

Can anybody recommend any suitable surfactant and defoamer for this purpose?

Dr. DIPANKAR SEN
- CALCUTTA,, WEST BENGAL , INDIA


2000

A. The foaming may be due to the surfactants present in the oil. Defoamers tend to be quite specific and the correct one must be selected for the job. I have had similar problems with spray cleaners and found that Triton DF12 was satisfactory. It is a low foam surfactant ex Rohm & Haas; now Union Carbide I think. The more you use the lower the foam providing temp above 35 C.

Roger Bridger
- Croydon Surrey UK


2000

A. My company uses blends of surfactants that both provide good cleaning and defoaming characteristics, Triton DF12 is a good recommendation. If you like, I can try to help you with some more combinations. Your problem is most likely surfactants in the lube: at high temperature they can come out of solution in the cleaner and foam, your silicone defoamers probably float, and are carried away by the foam.

Jeff Watson
Jeff Watson
- Pearland, Texas


2000

Q. Thank you Jeff for your comments. We are also looking for TRITON DF 12 to resolve problem. I understand that the source of foam is mainly saponification of semi synthetic rolling oil in presence of alkali. The emulsifiers present in the rolling oil composition may also be responsible for heavy foaming in the continuous degreasing line. We are also looking for surfactant source to resolve the problem.

Dr. Dipankar Sen.
- Calcutta, INDIA


2000

A. Dear Mr.Sen,

You should switch to demulsifying liquid cleaners, these materials are composed of two packages; a Builder - usually an Inorganic mix mostly and a Surfactant - In your case you should seek a LOW FOAM mixture and balanced enough so it can pop out the oil from your substrate and subsequently from the cleaning bath.

Domingos J C Spinelli
- SP Brasil


(2002)

Q. WE ARE IN THE FIELD OF MANUFACTURING METAL PRETREATMENT CHEMICALS. WE ARE ALSO FACING SIMILAR PROBLEM OF EXCESS FOAMING IN SPRAY CLEANERS. WE HAVE USED SILICON DEFOAMERS AND FOUND THAT IN HIGH ALKALINE SOLUTION SILICON DEFOAMERS HAVE LIMITED LIFE. THEY ARE EFFECTIVE WHEN ADDED FRESHLY. BUT THEIR EFFICIENCY GRADUALLY DECREASES WHEN THE POWDERED COMPOSITION IS DILUTED WITH WATER AND AFTER 3-4 HOURS PRACTICALLY IT LOOSES ITS DEFOAMING PROPERTY EVEN IF THE SOLUTION IS NOT USED.

WE ARE ALSO LOOKING FOR SUCH AND OTHER SPECIALITY PRODUCTS LIKE CRYSTAL REFINING AGENTS, SLUDGE CONDITIONERS FOR PHOSPHATING CHEMICALS AND DETERGENTS FOR ALKALINE AND ACIDIC SOLUTIONS. PARTICULARLY EFFECTIVE AT LOW TEMPERATURE OF 30 - 40 °C. ADDITIVES FOR PHOSPHORIC ACID TO IMPROVE RUST AND HEAT SCALE REMOVING PROPERTIES. WE WELCOME SUGGESTIONS.

PRABHAKAR GUPTA
- KANPUR, U.P., INDIA



August 15, 2018

Q. I am using fine cleaner -353 chemical in pre-degreasing and degreasing process but in tank heavy foaming is created during [operation]. Anybody help why foaming is created?

Bhoop Singh
Daikin - Alwar, neemrana, India



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