Hardly the flashiest aspect of the process, surfactants still play a major role in almost every paint and coating formulation. And as companies continue to concentrate on building more effective environmentally preferred technologies, such as waterborne and UV, finding surfactants that are compatible and deliver performance is key.
A Crucial Role
"Surfactants play a crucial role in all aspects of the production, and use of aqueous polymer dispersions (latices), but conventional surfactant technologies limit the performance of waterborne polymers when compared to solventborne formulations," said Igor Aksman, senior development associate, Uniqema Surfactants.
To that end, the polymers business of Uniqema has added a new pair of Maxemul non-migratory surfactants for use in waterborne polymer dispersions. The products–Maxemul 6106 and 6112-are copolymerizable surfactants with a phosphate ester functionality. Available as 100% active products, these new additions compliment Uniqema's previously released non-ionic Maxemul 5010 and 5011 products.
Maxemul 6106 and 6112 are intended for use in protective paint and coatings and adhesives and paper coatings, and offer performance through the entire span of a coatings life–from production to final film.
"These products offer substrate protection, coating durability, ease of formulation and improved appearance-and latex stability during production, storage, compounding and film formation," said Mr. Aksman. In addition the technology "positively affects film properties such as gloss, adhesion and blooming, and protective properties of the final coating such as water uptake and permeability."
Uniqema reports that the Maxemul product line has shown effectiveness in a wide variety of application areas, with particular success in "enabling vinyl acetate copolymers to attain performance approaching that of an acrylate system," Mr. Aksman added.
Air Products, Inc. has unveiled new products featuring its Gemini surfactant technology. The products-EnviroGem AE surfactants and EnviroGem AD01 low foam wetting agent-were launched to the market at ICE 2001 in Atlanta.
|R&D efforts at surfactant suppliers are centered on creating products that work well with environmentally - friendly coatings, including waterborne and UV|
EnviroGem AE surfactants are readily biodegradable, low foam wetting agents comprised of naturally occurring acids commonly used in food and beverage flavoring and are prepared using clean process technology. Air Products, which recommends their use in waterborne systems in automotive, industrial maintenance and wood coatings applications, contends the products can also be used in formulating overprint varnishes, pigment grinding and printing inks.
"In general, Gemini surfactants are more surface-active than their conventional counterparts," said Robert E. Stevens, technology manager for coatings and inks applications development and technical service for Air Products. "This allows for higher efficiency in wetting and foam control as well as the use of smaller hydrophobes and hydrophiles to achieve superior performance."
Gemini technology is not new-it has been in the market for more than 20 years via Air Products' Surfynol and Dynol surfactants. But with EnviroGem AD and AE series surfactants, Air Products has extended the technology beyond acetylenic diols. "This work has been in the R&D stage for several years and has been driven by recognition of overall trends in the surfactant market toward more environmentally friendly materials," Dr. Stevens said.
EnviroGem AD01 is recommended for formulators who want a 100% active, liquid, low-foam wetting agent that is clear and colorless and has low odor. According to Kelly A. Boyer, global marketing manager for specialty additives at Air Products, more EnviroGem products are in the pipeline. "There are other Gemini products currently under development to provide a broader range of performance benefits," she said.
Developing surfactant technology for environmentally friendly coatings has also been key at the Tego Coating and Ink Additives R&D lab. Part of the Degussa family, Tego has added a new class of polyether polysiloxanes-Tego Wet 270 and 280-for use in water-based and UV coatings systems. The products are designed to provide reduced surface tension with good compatibility, gloss and flow-all without significant foam or recoatability concerns, according to the company.
Tego is also offering the coatings market a new class of non-silicone surfactants for water-based and UV systems. Tego Wet 505 and 510 exhibit very low working viscosities and provide excellent flow and levelling properties, according to company officials.
DuPont and 3M have been working in the area of fluorosurfactant technology for coatings.
DuPont's newest entry is Zonyl, a full line of fluorosurfactants for use in coatings, adhesives and inks. Zonyl, which delivers good wetting, leveling and spreading, lowers surface tension and improves finish quality in water, solvent or 100% solids systems, according to the company.
3M has released a pair of long-term replacements that it contends outperform Fluorad FC-430 and provide improved environmental attributes. New Fluorad fluorosurfactants FC-4430 and FC-4432 are based on new chemistry that exhibits minimal toxicity to aquatic organisms and are unlikely to bioconcentrate, according to the company.
These nonionic polymeric fluorochemical surfactant additives provide low surface tension levels and can be used in waterborne and solventborne systems. 3M contends surface tensions as low as 20 dynes/cm can be reached in aqueous systems with concentrations as low 0.01-.10%. In some non-aqueous systems, surface tension can reach as low as 15 dynes/cm. The products are currently available in the U.S. and Europe; plans for global release are under way.