Paint & Coatings Industry - May 2008 - (Page 40)

Waterborne Alkyds Break Through the Performance Barrier New alkyd technology demonstrates superior performance with near-zero VOC content. ith the introduction of waterborne acrylic (latex) technology more than 50 years ago, commercial coatings manufacturers found an alternative to traditional solventborne alkyd chemistries that had been the mainstay of the coatings industry until that point in time. Waterborne paint chemistry offered significant advantages to both manufacturers and end users of coatings, including easier clean-up and lower VOC content when compared to solventborne alkyds, which required significant amounts of organic solvent additives during the manufacturing process. However, the switch to waterborne chemistries did not completely eliminate the VOC content of acrylic-based coatings. All acrylics, particularly “gloss” acrylic latex formulations, require the addition of organic solvents to enable coalescence and coating film formation. Engineers at Reichhold Coatings Division have recently developed a new waterborne alkyd resin technology that uses advanced processing technolFIGURE 1 | Surfactant-stabilized alkyd-latex micelle in emulsion. W ogy to produce a solvent-free alkyd formulation in a surfactant-stabilized aqueous emulsion. The soy-based resin, Beckosol AQ™ Alkyd Latex, provides all the benefits of a waterborne carrier with extremely low VOC content. Low VOCs vs. Paint Performance Characteristics Until the development of Beckosol AQ, coating manufacturers faced a trade-off between the reduced VOC content of waterborne acrylics (latex) and the superior performance in real-world applications of conventional solventborne alkyds in gloss rating, adhesion rating and stain-blocking abilities. Thus, coatings formulation engineers began experimenting with a way to combine the long-lasting, high-gloss performance characteristics of alkyds with the lowVOC, easy-to-use features of waterborne acrylics. Water-reducible formulations came first, created by adding solvents and other expensive intermediates (including amines) to the alkyd base to facilitate water compatibility. But because the amines also tended to catalyze the process of hydrolysis, the resulting paint had a shelf life of six months or less. Another type of waterborne alkyd formulation developed was the “core-shell” hybrid, in which acrylics are added to an alkyd base to create a quasisoluble mixture that is amine-neutralized to slow the process of hydrolysis. These formulations still required significant amounts of expensive alkyd intermediates and co-solvents, and shelf life of the resulting paint was only extended to 12 months. Unlike previous waterborne alkyds, Beckosol AQ is a surfactant-stabilized emulsion and does not require By Carl Sullivan, Coatings Technology Director | Reichhold, Research Triangle Park, NC 40 MAY 2008 | W W W . P C I M A G . C O M http://WWW.PCIMAG.COM

Table of Contents Feed for the Digital Edition of Paint & Coatings Industry - May 2008

Paint & Coatings Industry - May 2008 Contents Viewpoint Industry News Calendar of Events Company News Mergers and Acquisitions Names in the News Charlotte Dining Guide Exhibits-in-Print Waterborne Alkyds Break Through the Performance Barrier New Matting Agents for Waterborne Coatings and Varnishes Silicon-Based Technology for the Coatings Industry High-Performance Microgrinding The Development of New SMA Esters as Pigment Dispersants for Waterborne Coatings and Inks The Right Choice New Coating Technology Expands Color Choices for Vinyl Building Products BioPreferred Federal Biobased Products-Preferred Procurement Program European Union's REACH Regulation Sustainability - The New Nano Improved Dirt Pickup Resistance Critical to Future Coating Innovation NanoNews Protective Coatings NDT - Energy-Saving Paint Static Electricity - The Hidden Danger in Hazardous Areas Wacker Chemie - A Profile of Success Materials Watch Products and Literature Classifieds Advertiser Index

Paint & Coatings Industry - May 2008

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