Application Cases and Technical Analysis of Methyl Fluorosilicone Oil for Resolving Bubbling Issues in High-Solids Coating Spray Applications
Properties and Defoaming Mechanism of Methyl Fluorosilicone Oil
Methyl Fluorosilicone oil (also known as trifluoropropyl methylsiloxane oligomer) is a modified silicone oil primarily used in corrosion-resistant and solvent-resistant defoamers, lubricants, greases, and sealants. In the coatings industry, methyl fluorosilicone oil, due to its unique chemical properties, has become an effective solution for resolving bubbling issues in high-solids coating spray applications.

Key Characteristics
Low Surface Tension: Methyl fluorosilicone oil has an extremely low surface tension (20-21 dynes/cm), significantly lower than that of water (72 dynes/cm) and other foaming liquids. This property allows it to quickly penetrate thin layers of foam and spread rapidly across the foam surface, thereby destabilizing the foam.

Chemical Stability: Methyl fluorosilicone oil exhibits excellent chemical stability. Its Si-O bond is highly stable, allowing it to maintain its performance in complex chemical environments such as acids, bases, and salts. This stability enables it to function effectively in a variety of coating systems without reacting with other ingredients.

Thermal Stability: Methyl fluorosilicone oil remains stable over a wide temperature range, with long-term resistance up to 150°C and short-term resistance above 300°C. This thermal stability enables it to effectively defoam during coating production and application, especially under high-temperature conditions.

Defoaming Mechanism
Methyl fluorosilicone oil has a dual function as a defoamer in coatings:
Defoaming: Destruction of already formed foam (foam breaking)
Suppression: Significantly inhibits foam formation (foam suppression)
The defoaming process is primarily achieved through the following:

Rapid penetration into the foam film
Reduction of local surface tension
Disruption of the foam's mechanical equilibrium
Causing foam collapse and liquid discharge
Methyl fluorosilicone oil is used as a defoamer in very small quantities; typically, only 1 part per million (1 ppm) by weight of the foaming medium is needed to produce significant defoaming effects.

Bubble Problems and Solutions in High-Solids Coating Spraying
Characteristics and Challenges of High-Solids Coatings
High-solids coatings refer to coating systems with a high solids content (non-volatile components), typically exceeding 60%. These coatings offer the following characteristics:
Low VOC emissions and improved environmental performance
High film thickness, enabling a thicker film to be achieved in a single coat
Low solvent content and rapid drying
However, high-solids coatings are prone to bubble problems during spraying. The main reasons include:
High system viscosity, which hinders bubble escape
Rapid solvent evaporation, which can easily form "popping holes"
Air entrainment during spraying
Air release from pores on the substrate surface