Raw material preparation → reaction system configuration → process control → purification → packaging
The production process of defoamer follows the core process of raw material pretreatment, reaction system configuration, key process control, purification treatment and standardized packaging. The specific steps of different types of defoamers are different.
General production process
Raw material preparation
Select the basic materials according to the type of defoamer: for example, silicone requires silicone oil and emulsifier (dimethyl silicone oil, hydroxy silicone oil, etc.), polyether requires fatty alcohol and alkylene oxide, and stearic acid requires stearic acid and ethylenediamine, etc.
The raw materials need to be strictly screened for purity. For example, the water solubility of silicone oil needs to be controlled by hydroxyl value, and stearic acid needs to meet the acid value standard.
Reaction system configuration
Add the raw materials to the reactor in proportion. For example, silicone defoamer needs emulsifier to disperse silicone oil to form an emulsion, and stearic acid needs to be generated by esterification reaction. ethylenebisstearamide.
The amount of solvent (such as water and white oil) added needs to be precisely controlled to adjust the viscosity and stability of the system.
Process Control
Temperature and Pressure: The reaction of silicone emulsion needs to maintain 160~180℃, 0.1~0.2MPa, and stearate esterification needs 120~150℃.
Time and Stirring: The reaction time is determined according to the endpoint (such as pH stability), and high-speed stirring (more than 3000 rpm) ensures uniform dispersion.
Purification Process
Remove unreacted impurities by filtration, recover solvents by distillation, and improve product color by bleaching (hydrogen peroxide treatment).
Emulsion type needs centrifugation or static stratification detection to ensure stability (such as no stratification at 3000 rpm/20 minutes).
Packaging and Storage
Moisture-proof and light-proof packaging, liquid wax or white oil as a carrier needs to be sealed to prevent oxidation.
Typical process examples
Organic silicone defoamer: Silicone oil and emulsifier are emulsified at high temperature under nitrogen protection → neutralize pH to 6-8 after cooling → centrifugal purification → packaging.
Stearic acid ethylenediamine type: esterification of stearic acid and ethylenediamine → compounding with diethylene glycol oleate → dispersion and cooling in liquid wax → finished product.
Quality control points
Performance test: including pH value (6-8), temperature resistance (no demulsification at 130℃), dilution stability (0.5%-5.0% dilution does not foam).
Safety specifications: high temperature and high pressure reactions require explosion-proof design, and the use of solvents must comply with chemical safety standards.