Antifoams in Water-Based Systems
Foam formation in water-based paints occurs due to air molecules remaining in the system during the production process or application. The combination of raw materials used in water-based systems with these air molecules causes stable foam formation (micro and macro foam) on the outer surface and/or within the system.
Foam Control Agents in Water-Based Systems
Foam formation in water-based paints occurs due to air molecules remaining in the system during the production process or application. The combination of raw materials used in water-based systems with these air molecules causes stable foam formation on the external surface and/or within the system (micro and macro foam).
In addition to system viscosity, the following raw materials also cause foam formation in the system;
• Resins,
• Wetting agents,
• Grinding agents,
• Waxes.
The problems that foam would create in your system are;
• Inefficient filling of production tank,
• Inefficiency during grinding stage,
• Reduction in transparency and gloss,
• Surface defects (crater formation),
• Negative impact on flow.
For this reason, additives must be used to prevent or eliminate foam formation. To eliminate and/or prevent foam that forms in paints and coatings, 'antifoam' foam control agents should be used. Foam control agents are classified as Defoamer or Deaerator (gas release agent) according to their specific properties (those most effective for micro or macro foam).
Defoamer agents prevent macro foam formation on the surface, while the primary function of Deaerator agents is to prevent micro foam formation within the system. Both agents (Defoamer and Deaerator) change the surface tension of foam formed in the system. Defoamers spread rapidly and perfectly onto the foam surface, reducing the existing surface tension and allowing air bubbles to escape from the liquid film, while Deaerators collect small bubbles together (depending on their specific gravity) and bring them to the paint surface, thereby preventing foam formation.
The properties of foam control agents used in paint include;
Characteristics
• Providing high stability,
• Excellent foam prevention power,
• Free from volatile substances,
• Odorless,
• Suitable for both micro and macro foam
Application Areas
• Decorative paints,
• High PVC paints,
• Coatings,
• Pastes,
• Gloss and matte paints,
• Adhesives.
Due to the generally high surface tension of water-based systems, a wider range of chemical products can be used in these systems. Among these products, oil-based and silicone-based ones are particularly effective. Since foam control agents do not dissolve easily in the system, mixing speed and duration must be controlled to ensure optimal distribution of the active substances. These active substances enable foam control agents to spread easily over all air-water interfaces.
In What Amount and at What Stage Should Foam Control Agents Be Added to Paint?
For water-based decorative paints;
1. 50% during the middle phase of the production process while mixing,
2. 50% slowly mixed in during the final stage of production,
3. In the range of 0.2% to 0.5% of total formulation.
Siliconi SPA's Antifoam WS 938, Antifoam WS 974, Antifoam WS360 silicone-free foam control agents are foam breakers used in water-based paints and coatings that contain no volatile substances, have high stability, high performance, and are compatible with resins and other agents.
The innovative product Antifoam WS 360 developed by Siliconi SPA is made from environmentally compatible substances. Antifoam WS 360 is used to control and/or prevent foam formed during production in emulsion paints, coatings, plastic paints, decorative paints and special emulsion paints. An effective product for plastic paint mixtures, Antifoam WS 360 demonstrates excellent stability in both ready-made paint formulations and under long storage conditions.
Antifoam WS 360, which provides high compatibility with water-based systems, contains no VOC and is odorless. The paint's appearance, odor or application are not negatively affected, and it also does not cause any problems in the dry film (fish-eye defects). The most important point is that Antifoam WS 360 can be effectively used in place of petroleum-derived foam control agents in paint formulations, thus helping to create paint systems more compatible with the environment. Antifoam WS 360 is suitable for gloss, semi-gloss, high PVC content paints, coatings and textured paints, and can also be used in emulsion resins and inks thanks to its deaerator properties. Below you can see graphs comparing various foam breakers in high PVC content paints and water-based paints:
Özge Şahin Turan - Sales Manager - Arkem Kimya San. ve Tic. A.Ş.
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