Surfactants play several key roles in the manufacture, storage, application and curing of all types of paint and coatings. "Wetting and dispersing agents are essential in improving the color strength and stability of pigment concentrates and coatings," said Shelley Parkerson, market development manager, OMG Americas, Inc. "Flow and leveling agents are essential in aiding the flow of high performance coatings to give a superior appearance. Surfactants to help with air release of the coatings are essential for high solids and waterborne coatings."
At a minimum, a surfactant should enable a water-based formulation to better wet out the desired substrate, according to Ingrid Meier, technology manager, specialty additives, Air Products. "A surfactant is critical to being able to apply water-based coatings on hydrophobic substrates like plastic or very porous substrates like wood," she said. "Often times, surfactants are used as dispersants for pigments and fillers or as emulsifiers in the formulation. Certain surfactants are also capable of improving the flow and leveling of a coating, which will dramatically improve the surface appearance of the finished coating. When coatings need to be applied under dynamic conditions like spray, a surfactant that can provide dynamic surface tension reduction will be required to achieve the desired results."
Surfactants are key additions to waterborne coatings formulations. "They are used as binder emulsifiers and as pigment dispersants," said Caio Sedeno, global product director Dow Polyglycol & Surfactants. "Surfactants are also needed to improve wetting on low energy substrates, to modify rheology during application and processing, improve freeze/thaw stability and prevent film defects caused by surface tension gradients."
When it comes to the paint and coatings market green technology is the current hot buzzword, but in reality it takes more than a green label to make a product environmentally friendly.
"In paint and coatings what we consistently see is more emphasis on performance and economy, rather than any specific push for greener chemistry," said Sedeno. "Formulators continue to em�phasize reducing VOC content, ingredients that have better toxicity profiles and improved handling properties." Dow's Ecosurf SA surfactant (launched late 2007) is based on a natural hydrophobe; both Ecosurf SA and Ecosurf EH are readily biodegradable. "The aquatic toxicity for Ecosurf EH surfactants is better than many other conventional ethoxylates," Sedeno added.
OMG has designed its new 100% active wetting and dispersing agents to be compatible with solventborne, waterborne and high solids coatings. "As a result, the coatings producer can formulate universal pigment concentrates," said Parkerson. "Many of our flow and leveling agents, and air release agents, are 100% active and contribute no VOCs to the final coating. Many are also compatible with new green resins based on renewable sources as well as UV curable coatings."
"Paint and coatings based on latex produced by emulsion polymerization are essentially water-based so by their very nature are essentially 'green alternatives' to solvent or UV technologies," said Maureen Mackay, global marketing manager speciality additives, Cytec Industries. "Effectively, only small steps can be taken to make such products greener. Examples of these could be more biodegradable surfactants and improved processes to reduced energy consumption and waste generation.
"While all of Air Products' surfactants, dispersants and defoamers have been designed to perform in waterborne coating systems, our most recent surfactant technology has been specifically tailored to help our customers meet their environmental requirements," said Meier."
EnviroGem surfactants are all capable of providing efficient wetting while also acting as coalescing surfactants. "This means that, when used at typical surfactant use levels, they lower the minimum film formation temperatures (MFFT) of the coating, and enable better film coalescence," Meier added. "By using EnviroGem surfactant in the coating formulation, a paint manufacturer should be able to reduce the level of coalescing solvent used and thus lower VOCs of the coating. We have also introduced our Carbowet surfactant product line that has been designed to provide environmentally-preferred alternatives to traditional alkylphenol ethoxylate-containing surfants."
Ciba Corporation has also been working on environmentally compliant surfactant products. "These novel surfactants have applications in compliant coatings sectors such as waterborne, UV and powder coatings," said Bernadette Corujo, director, NAFTA marketing, coatings, Ciba Corporation. "Ciba's products are listed under the EFKA trade name. The chemistries include controlled free radical polymerization; reactive polyacrylates, polyacrylates, polyurethanes, FAME (fatty acid modified emulsions), polysiloxanes, 100% actives and zero VOC technologies."
Air Products recently launched Enviro�Gem 360 surfactant as a low foam superwetter for plastic wood and other industrial coatings applications. It also launched Carbowet 106, 109 and DC01 for the architectural coatings market. "EnviroGem 360 functions as a superwetter and provides excellent substrate wetting and flow and leveling benefits in addition to its ability to lower the MFFT of the coating," said Meier. "Carbowet surfactants were designed to offer better performance attributes that are equal to or better than those of traditional octypheol and nonylphenol ethoxylates, allowing customers to formulate away from this increasingly undesirable chemistry. "
Ciba offers EFKA 4310, a high molecular weight dispersant for organic pigments. The product is based on Ciba's proprietary controlled free radical polymerization process. EFKA 4310 offers improved dispersion at reduced grinding time. According to the company, this product has excellent performance with carbon black, quinacridone, Cu-Phthalo-cyanine blues and perylene pigments.
EFKA 2580 is a new silicone-based defoamer for water-based systems. It is easy to incorporate into the coating and has broad compatibility and augments EFKA 2550.
Cytec Specialty Additives has focused its efforts on the development of two new surfactants, Aerosol EF-800 and EF-810. Both of these products are APE-free and are biodegradable. "Both products are designed for acrylic, vinyl-acrylic and styrene acrylic coatings formulations," said Mackay. "The products represent a viable option for customers looking to formulate coating systems that are APE-free. The products are especially efficacious in hydrophilic monomer-based systems."
Cytec is also focusing its efforts on Aerosol A-22 surfactant, which has demonstrated the ability to impart enhanced pigment/filler compatibility allowing easier formulating providing improved water resistance, hiding, color developments and shelf stability to coatings formulations.
Recently, OMG has introduced two polymer PU-based wetting agents, 100% active matter, one available for waterborne and UV coatings, the other one for solventborne coatings. "Both are highly efficient with difficult pigments like organic red and carbon black," said Parkerson. "We have also introduced two new flow agents that bring slip and air release to high performance waterborne coatings."
OMG recently launched dispersing agents, Borchi Gen 0754, 100% active dispersing agent for organic pigments and Borchi Gen 0755, superior dispersing agent for carbon black in solvent based coatings. Flow and air release agents include Borchi Gol LA 232- high slip agent for high performance coatings, 100% active and Borchi Gol LA 50- substrate wetting additive for high performance, 50% in DPnB. Products for new industrial coatings applications Borchi Gen 0451,100% active very good for organic and nano particles, Borchi Gol 0011- 98% solvent free, good for high solids coatings including poly ureas and poly aspartic esters amd Borchi Gol LA 200- Flow and dearation of 2K waterborne PUR, 100% active.
The Ecosurf EH line of surfactants is Dow's latest addition. "Ecosurf EH surfactants are a new line of specialty surfactants designed to help customers meet rising expectations for performance and convenience while complying with more stringent environmental expectations and safety regulations," said Sedeno. "These new patent protected, non-ionic surfactants provide superior performance benefits in many formulations over many other, commercially available alternative surfactant chemistries. These advantages are particularly evident in applications such as hard surface cleaning, textile processing, paint and coatings and agrochemicals where good wetting is a determining property in surfactant use."