Silicone-free defoamer operation guide: key steps for efficient use
Silicone-free defoamer operation guide: key steps for efficient use
1. Applicable scenarios and defoamer type selection
Water-based system (such as water-based paint, water-based ink)
Recommended types: polyether, mineral oil, polymer defoamer
Key requirements: balance defoaming and system compatibility to avoid affecting gloss or coating adhesion.
Application example: Adding 0.1%~0.5% polyether defoamer to water-based paint can effectively solve the bubbles generated in the grinding stage and avoid shrinkage.
Oil-based system (such as solvent-based ink, adhesive)
Recommended types: mineral oil, natural oil, fatty acid amide derivatives
Key requirements: high temperature resistance, shear resistance, and avoid reaction with the resin system.
Application example: Adding 0.3%~0.8% mineral oil defoamer to UV ink can prevent bubbles from remaining due to stirring during printing.
High viscosity system (such as pressure-sensitive adhesive, hot melt adhesive)
Recommended type: polymer type, modified polyether defoamer
Key requirement: It must have long-lasting anti-foaming ability to avoid the defoamer failure at high temperature.
Application example: Adding 0.5%~1.0% polymer defoamer to hot melt adhesive can ensure effective defoaming at temperatures above 180°C.
Food and pharmaceutical fields
Recommended type: natural oils, plant extracts, polyglycerol esters
Key requirement: It must comply with FDA, GB and other regulatory standards and be non-toxic and harmless.
Application example: Adding 0.05%~0.1% natural oil defoamer in food processing can effectively eliminate foam during fermentation without affecting the flavor of the product.
2. Usage and precautions
When to add
Grinding stage: Add before pigment dispersion to destroy the bubble generation environment in advance.
Painting stage: Add in the later stage of paint mixing to avoid excessive shearing and destruction of the defoamer.
Construction stage: Add an appropriate amount before spraying and printing to ensure good system fluidity.
Dosage control
Low dosage: usually 0.1%~1.0% (adjusted according to the viscosity of the system). Excessive dosage may cause shrinkage and poor leveling.
Step-by-step testing: It is recommended to start with a small dosage and gradually increase to the best effect to avoid excessive dosage at one time.
Dispersion process
Low-speed stirring: After adding, stir at a low speed of 300~500rpm for 5~10 minutes to avoid high shear damage to the defoamer structure.
Pre-dispersion: The defoamer can be pre-dispersed with some solvents or resins and then added to the system to improve uniformity.
System compatibility test
Compatibility verification: simulate actual process conditions in the laboratory to test the effect of the defoamer on the transparency, viscosity and curing time of the system.
Long-term stability: observe whether the system has stratification, precipitation and other phenomena after 72 hours.
3. Common problems and solutions
Poor defoaming effect
Reason: The defoamer type does not match the system, the dosage is insufficient, and the system temperature is too high.
Solution: Change the defoamer type, increase the dosage, or reduce the system temperature and retest.
Shrinkage and pinholes
Reason: excessive addition of defoamer, incompatible with the system.
Solution: reduce the amount added, or choose a defoamer with better compatibility with the system.
Short antifoaming time
Reason: Defoamer has poor temperature resistance and is easy to precipitate in the system.
Solution: Select a polymer defoamer with better temperature resistance, or optimize the system formula to enhance compatibility.
Affecting gloss
Reason: Defoamer is enriched on the surface of the system to form an uneven coating.
Solution: Select a defoamer with low surface tension, or reduce the impact by adjusting the construction process (such as reducing the spraying pressure).
4. Recommended defoamer types and characteristics
Polyether defoamer
Advantages: fast defoaming speed, long-lasting antifoaming, good compatibility.
Applicable scenarios: water-based coatings, water-based inks, emulsion polymerization.
Mineral oil defoamer
Advantages: low cost, high temperature resistance, shear resistance.
Applicable scenarios: oil-based inks, adhesives, hot melt adhesives.
Natural oil defoamer
Advantages: non-toxic, harmless, environmentally friendly and safe.
Applicable scenarios: food processing, pharmaceutical field.
Polymer defoamer
Advantages: strong temperature resistance, long-lasting foam suppression, not easy to precipitate.
Applicable scenarios: high viscosity system, high temperature process.
5. Summary and suggestions
Accurate selection: select the appropriate defoamer according to the system type, process conditions, and regulatory requirements.
Scientific testing: verify the performance of the defoamer through laboratory simulation tests to avoid problems in direct production.
Optimize the process: adjust the addition time, stirring speed and other process parameters in combination with the characteristics of the defoamer to achieve the best effect.
Continuous improvement: regularly evaluate the performance of the defoamer and adjust the formula or process in time according to system changes.
The above suggestions can effectively solve the common problems of non-silicone defoamers in the application and improve product performance and production efficiency.