How to Choose a Water-Based Defoamer for Water-Based Coating Ink?
Choosing an appropriate water-based defoamer is the core key to ensuring stable performance of coatings and inks throughout the entire process of production, processing, long-term storage, and on-site construction. The following is a complete selection reference plan:
I、 First, understand the main types of defoamers
Type | characteristics | Applicable scenarios |
mineral oils | Low cost, good compatibility, long-lasting foam inhibition | Flat/matte paint, primer |
Silicone-based | Strong defoaming power, fast speed, low dosage, high efficiency | A system that requires rapid defoaming |
Polyether modified siloxane | Balancing defoaming and leveling, with excellent compatibility | High gloss topcoat and varnish |
Polyether class | Good compatibility and less prone to shrinkage | A system with high compatibility requirements |
Composite polymer type | Long term foam suppression without affecting recoating properties | Foam problems are prominent, dip coating production process |
II、 Core selection principle
1. Select based on system viscosity
Low viscosity systems such as water-based ink, suitable for self emulsifying or polyether modified siloxane additives, with uniform and stable dispersion, can effectively avoid shrinkage problems.
For high viscosity systems such as latex paint, mineral oils or organosilicon defoamers can be used to achieve stronger defoaming effects.
2. Choose according to the gloss requirements of the coating film
• Excellent High gloss Varnish System: Choose polyether modified siloxane or pure polyether defoamer first, which can avoid the shrinkage and gloss reduction problems caused by ordinary organosilicon. RK-8405 is recommended.
Matte/flat gloss system: Mineral oils or organosilicon defoamers can be used, resulting in lower overall operating costs.
3. Choose according to the construction process
workmanship | Recommended Type | reason |
spraying | Polyether with good compatibility | Avoid shrinkage and fisheye |
Roller coating/brush coating | Silicone-based | Quickly burst bubbles |
Spray coating/dip coating | Polyether modified siloxane | Low foaming, long-lasting foam suppression |
4. Choose according to the foaming stage
• Grinding stage: select foam suppression type to prevent a large amount of foam generated by grinding temperature rise;
• Paint mixing/filling stage: select foam breaking type to quickly eliminate the generated foam;
• Construction phase: Select defoaming type to help microbubbles escape from the paint film
III、Special considerations for paint vs ink
Coatings field
In recoating scenarios, it is necessary to control the amount of organic silicon additives added to prevent weakening of the interlayer adhesion of the coating;
In outdoor durability scenarios, it is important to focus on the potential negative impact of defoamers on the long-term weather resistance of coatings;
In the scenario of anti-corrosion system, some defoamers may weaken the anti-corrosion performance of the coating, and it is necessary to conduct matching adaptation tests in advance.
Ink field
In terms of printing suitability, the selected defoamer must not interfere with the transferability of ink, nor reduce the clarity of the final printed image;
In terms of dryness control, it is necessary to avoid the problem of defoamers slowing down the drying speed of the system and damaging the final film quality;
Color restoration dimension, in high transparency ink systems, it is necessary to avoid fog or flower defects caused by defoamers.
IV、 Practical testing suggestions
1. Compatibility testing operation: Add defoamer to the varnish system and observe whether there are any abnormal phenomena such as turbidity and shrinkage;
2. Defoaming efficiency test method: measure the foam height and defoaming time of the system after high-speed mixing operation;
3. Long term stability test: Store the sample in a 50 ℃ environment for two weeks and observe whether the system has delamination or failure problems;
4. Construction simulation stage: Based on the actual construction conditions on site, carry out verification work on the final landing effect;
5. Usage optimization operation: usually starting from the addition range of 0.1% -0.5%, gradually adjusting to find the best balance between performance and cost
V、 Common Matching Strategies
During the grinding stage, mineral oil additives are used to suppress foam, while during the paint mixing stage, organic silicon products are used to break the foam;
In the high light system scenario, polyether modified siloxane monomer is selected as the defoaming component;
For sensitive systems such as automotive paint, polymer or high-purity polyether defoamers are preferred.
