Be careful when using grinding defoamers: avoid these"invisible traps"

Be careful when using grinding defoamers: avoid these "invisible traps"

Grinding defoamers are the "foam killer" of industrial production, but if used improperly, they may cause quality problems. From the laboratory to the production line, these key precautions can help companies avoid common misunderstandings.

1. The "sweet trap" of excessive addition

"Adding a little more is safer" is a common misunderstanding. Excessive defoamers can lead to a reverse effect: hydrophobic particles are oversaturated, and new foam cores are formed instead. In paint production, excessive defoamers may cause shrinkage holes in the paint film. For example, a certain automotive paint factory once caused a 20% surge in the rework rate of the entire vehicle paint surface due to an excess of 3% in the addition amount. It is recommended to determine the optimal addition amount through a step experiment, which is usually controlled at 0.1%-1% of the total system.

2. The "survival boundary" of pH value and temperature

Different defoamers have their own "comfort zone". Polyether defoamers perform best in the pH range of 4-8. If used in a strong acid plating solution (pH<1), they may fail quickly. In terms of temperature, mineral oil defoamers are easy to volatilize at high temperatures. A ceramic factory used ordinary defoamers in the glaze sintering process (120℃), which caused the foam to return in the second half of the temperature rise. When selecting, it is necessary to check the product's temperature resistance curve and use high-temperature resistant silicone defoamers when necessary.

3. The "golden window" of adding time

Premature addition may cause the defoamer to be destroyed by high-speed shear force. In ink grinding, the best time to add is in the late grinding stage (when the particle size is <10μm), when the foam stability is reduced and the defoamer efficiency can be increased by 40%. For the circulating grinding system, it is recommended to use a continuous dripping method to maintain the effective concentration of the defoamer in the system.

4. The "chemical marriage" of compatibility

The defoamer and the surfactant in the system may be "incompatible". In a pesticide suspension formulation, the cationic defoamer reacts with the anionic dispersant, resulting in system stratification. Solutions include: selecting a non-ionic defoamer, or conducting a small-scale compatibility experiment in advance. For electroplating solutions containing metal ions, avoid using sulfur-containing defoamers to prevent metal sulfide precipitation.

5. "Invisible killer" of storage environment

High temperature and light will accelerate the failure of defoamers. A food processing plant stored defoamers in a warehouse exposed to direct sunlight. After three months, the defoaming efficiency dropped by 60%. It is recommended to store in a cool and dry place and use as soon as possible after opening. For water-based defoamers, avoid freezing to prevent the active ingredients from crystallizing and precipitating.

6. "Bottom line principle" of environmental protection and safety

Although PFOS-containing defoamers are highly efficient, they have been banned in many countries. The EU REACH regulation requires that the VOC content of defoamers is less than 1%. A certain export company failed to update the formula in time, resulting in the return of the entire batch of goods. In the field of food and medicine, it is necessary to use FDA or GB standard certified products, such as phospholipid natural defoamers, to avoid the introduction of toxic residues.

7. "Triple Insurance" for Effect Verification

Laboratory test: Verify defoaming speed and anti-foaming time in a 500ml simulation system

Pilot tracking: Run continuously for 8 hours in a 10L pilot device to detect foam regeneration

Long-term monitoring: Take samples from each batch after formal production to observe changes in yield and customer complaint rate

Correct use of grinding defoamers is like "walking on a tightrope", which requires precise control of dosage, timing, and environment. It is recommended to establish a defoamer usage file to record the addition effects of different batches of products and find the best practice solution through data accumulation. When encountering a complex system, you may wish to contact the defoamer supplier for customized formula design. After all, "the right one is the best."