Replacement Challenges

One issue in finding alternatives for fluorinated surfactants, or fluorosurfactants, is that many alternatives do not provide the same level of performance or the host of performance benefits that fluorosurfactants offer. Momentive’s CoatOSil™ additives, which are based on silicone chemistry, have been tested to show comparable to or even improved performance over fluorosurfactants in several properties relevant to achieving durable and visually stunning coating films on a variety of substrates. There are two categories of Momentive’s CoatOSil™ additives (designed to replace fluorosurfactants): surface modifiers and antiblocking.

CoatOSil™ Surface Modifier Additives

Momentive’s surface modifier additives, such as CoatOSil™ 1211C and CoatOSil™ 7001LC, are based on silicone–polyether blends and block copolymers, respectively. CoatOSil™ 1211C is used to reduce the liquid surface tension of waterborne systems, and CoatOSil™ 7001LC is used for the same purpose in solventborne formulations. Both additives may also be used in UV-curable coating formulations and may also be known as superspreading additives, owing to their efficacy. Typical applications for these additives include coatings for equipment, electronics, transportation, and packaging.

Wetting

CoatOSil™ 1211C reduces surface tension to 22 mN/m when put in solution with water at a 0.1% w/w addition rate at 25°C. CoatOSil™ 7001LC, though meant for use in solvent-based formulations, can reduce the surface tension of water to 27.8 mN/m under similar conditions. These additives reduce surface tension very rapidly, as shown in the graph below. Here, a 0.1% w/w solution of CoatOSil™ 1211C in water lowered the surface tension from 60 mN/m to 30 mN/m within one second. This is compared to a benchmark made using 0.1% w/w of a competitive surfactant and a defoaming agent in water. Such quick action makes it useful in spray or high-speed roll coating applications.
 

Superspreading

CoatOSil™ 1211C’s superspreading ability is demonstrated below, where aliquots of dyed aqueous samples were applied to a polystyrene substrate. Samples were prepared with and without CoatOSil™ 1211C. The sample without CoatOSil™ 1211C had a spreading area of 0.15 cm2, whereas the sample containing CoatOSil™ 1211C achieved a spreading area of 8 cm2, demonstrating the efficacy of the additive at 0.5% concentration.
 

Foam Reduction

CoatOSil™ 1211C achieves the properties above with minimal foam, reducing the need for defoaming additives typically used in formulations that use surfactants for achieving wetting. Below, tests were made comparing the foam height generated in a glass bottle after shaking. As seen, CoatOSil™ 1211C alone generates less foam than a benchmark surfactant combined with a defoaming agent.
 

Leveling and Block Resistance

Both CoatOSil™ 1211C and CoatOSil™ 7001LC help reduce surface defects in coating films by improving leveling. CoatOSil™ 1211C is even able to improve wetting and leveling on oil-contaminated substrates. Both additives can improve gloss and eliminate cratering, pinholing, fish eye, and orange peel film defects associated with poor leveling on low–surface energy substrates. CoatOSil™ 7001LC and a related additive, CoatOSil™ 7001, which is meant for two-component systems, even help promote resistance to blocking and abrasion, improving coating film durability.

CoatOSil™ Antiblocking Additives

Momentive’s antiblocking additives, such as CoatOSil™ SE 620, are recommended for applications that consistently face harsh external environments, namely exterior architectural paints and sealants. CoatOSil™ SE 620 is a functional silicone emulsion that improves the wetting and leveling of formulations on a variety of substrates while imparting various other properties, listed below.

•    Improved blocking resistance
•    Increased resistance to weathering and yellowing from UV exposure
•    Expanded resistance to staining due to increased oleophobicity and hydrophobicity
•    Enhanced dirt pickup resistance (DPUR)

Compared to fluorosurfactants and other fluorochemical-based additives that cover the properties above, CoatOSil™ SE 620 performs equally or better. Therefore, CoatOSil™ SE 620 is an ideal alternative or replacement for such chemistry. Check out the video below to view water repellency and weatherting performance of this grade in paint formulations.

 

CoatOSil SE 620 Final Video

 

CoatOSil™ Grades

Summary

Coating, paint, ink, and sealant formulators looking to replace PFAS in their formulations will find that Momentive’s CoatOSil™ surface modifier and antiblocking additives are ideal alternatives. In many performance categories, they perform similarly to or better than fluorosurfactants and other fluorochemical-containing performance additives. From wetting to leveling to antiblocking to weathering resistance, there is a CoatOSil™ grade that can significantly boost system performance while keeping formulations ahead of rapidly changing regulations. ChemPoint is here to help modernize your formulations with ingredients that improve performance, sustainability, and regulatory compliance. Click below to discuss your formulation with one of our coating formulation experts and request a CoatOSil™ sample.