Innovation has been the foundation of the paint and coatings industry since its inception. New resin technologies and additive and pigment chemistries are constantly being developed to address key needs in the marketplace for performance and sustainability. Two new exhibitors at the upcoming American Coatings SHOW in Indianapolis (April 12–14) provide excellent examples of the types of innovation driving the coatings industry forward today. Both are based on technologies developed by academic research groups, also underscoring the growing importance of open innovation and technology transfer. Liquiglide offers coatings developed by researchers at the Massachusetts Institute of Technology (MIT) that make surfaces permanently wet and slippery so that viscous materials will slide easily, while Renuvix is commercializing biobased resin chemistries developed by scientists at North Dakota State University (NDSU).
Reducing Waste and Improving Efficiency
LiquiGlide’s patented technology platform enables the creation of custom coatings that enable any viscous liquid to slide easily across a surface, according to CEO and co-founder Dave Smith. The coatings are not single materials, but combinations of textured solids and liquids, resulting in permanently wet, slippery surfaces. A hierarchical micro-nanoscale texture is first created on the surface and then impregnated with an appropriate lubricant, the choice of which is determined by the surface energies of all of the phases present in the system. Unlike super-hydrophobic surfaces that mimic the lotus leaf through the incorporation of nano-scale textures that create a cushion of air for the product to sit on, liquid-impregnated LiquiGlide coatings consist of a matrix of solid features spaced sufficiently close to stably contain an impregnating liquid that fills in the spaces between the features. The liquid is held in place within the texture by capillary forces, creating a permanently slippery, liquid surface. As a result, the product actually slides on the liquid layer via a liquid–interface.
LiquiGlide custom designs each coating for a given application. Liquids are first identified that are compatible with the chemical and physical properties of the viscous product. Solid materials with good adhesion to the surface on which the product must slide and that will form a suitable porous structure are then selected. Combinations are then investigated to identify the porous solid that most effectively entraps the liquid through capillary forces and provides the desired slippery surface. Once a prototype has been formed, a scalable and commercially viable application process is tested. The company can even control the speed at which liquids slide over the surface by changing the materials or structure of the coating.
“The choices for solids and liquids number in the hundreds and are selected based on the chemistry of the product and application requirements,” says Smith. “Because LiquiGlide coatings are so versatile and can work for so many different surfaces, including glass, plastic, ceramic, and metal, they can be applied to countless applications across many industries,” he adds. Obvious applications include the interiors of product packaging for viscous liquids (think ketchup or lotion). These coatings can also be applied to pipes, processing vessels, storage vats, etc., to improve the efficiency of manufacturing, cleaning, and transportation processes for viscous materials. “LiquiGlide reduces waste and improves efficiencies, and can also enable the creation of completely new commercial opportunities,” Smith asserts. LiquiGlide will be exhibiting at ACS, highlighting its permanently wet coatings that prevent products from sticking to packaging and manufacturing equipment.
Performance and Sustainability
Renuvix is commercializing biobased resin chemistries that offer advantages over other, currently available biobased technologies, according to chief technology officer Bret Chisholm. “Renuvix products are completely or largely based on renewable starting materials and thus represent more environmentally friendly alternatives to petrochemicals. In addition, the unique molecular architecture of these materials allows for excellent properties, such as high cured film hardness, solvent resistance, and gloss,” he says.
At ACS 2016, the company will be promoting two commercial products: EsseneoTM SS8 and Esseneo SS8H sucrose esters of vegetable oils with a compact molecular structure and a high number of reactive functional groups. EsseneoSS8 is a highly esterified sucrose soyate polyester that is 100% biobased and has low viscosity. Due to its unsaturation, it can be used as a reactive diluent in solventborne alkyd paint systems to enable low-VOC, high solids formulations or emulsified for use in emulsion paints. Esseneo SS8H is a hydrogenated sucrose soyate polyester. Although the primary application is in lubricants, it has potential for use as a wax additive for coatings to impart water repellency and other properties associated with waxes. It is 100% biobased and has a melting temperature of 60°C.
Renuvix is also planning to commercialize other biobased resins based on sucrose polyesters, including an epoxy derivative (Esseneo ESS8), a polyol derivative (Esseneo SS-OH), and an acrylate derivative (Esseneo AESS). Compared with commercial soybean oil-based analogs currently on the market, these sucrose polyester derivatives provide for dramatically higher hardness, modulus, strength, and glass transition temperatures when used to produce thermoset materials. In addition to these biobased resins based on sucrose polyesters, Renuvix is also developing polymers from vinyl ether-functional oleochemical monomers for a variety of applications, including personal care products, paints and coatings, and lubricants.