Paint & Coatings Industry - May 2008 - (Page 46)

New Matting for Waterborne Coatings and Varnishes A good matte finish is often required in coatings formulations. In order to fully optimize this important parameter, Michelman has recently developed two wax dispersions: Michem® Guard 349 and Michem Guard 350. Both dispersions aid in imparting a matting effect to most aqueous coatings and varnishes, while enhancing other properties such as abrasion resistance and water repellency. Characterized by a large particle size, both Michem Guard 349 and 350 extend the range of existing Michelman additives for surface modification in coating applications. Building on an existing range of water-based dispersions, these new wax dispersions are designed to highlight the positive properties of large-particle-sized wax and minimize unnecessary interaction from dispersing agents. How Does a Wax Dispersion Control Matting? As a coating film dries, wax particles are transported to the film surface as a consequence of the turbulence flow induced by the water evaporation. Because of the large particle size, protruding wax particles create a certain degree of micro-roughness, induced as the film shrinks. As a result, the incident light is scattered instead of being reflected, conveying the impression of low gloss or matte appearance. The degree of the so-created micro-roughness is determined by the number of particles present at the surface, which directly depends on wax properties such as: particle size and particle size distribution; particle density; and amount of matting agent incorporated. TABLE 1 | Characteristics of Michem Guard 349 and 350. Characteristics Emulsion type Solids content (%) Viscosity #3 @ 60 rpm (cps) Particle size (μm) pH Hardness @ 25 º C Larger Particle Size Optimizes Appearance Unlike wax emulsions – where the particle size is much lower than 1 µm – large-particle-size wax dispersions modify the optical properties of a coating. Not only do wax dispersions reduce gloss, as explained previously, but also significantly impact other surface properties. Formulations based on Michem Guard 349 and 350 will benefit from: • enhanced scratch, mar and abrasion resistance; • improved barrier properties such as water repellency; • enhanced slip and anti-blocking; and • enhanced soft-feel. In addition, the new wax dispersions present the following features: • totally solvent-free; • do not contain APE; • reduced amount of surfactant; • high solids content; • no tendency for sedimentation; • easy incorporation by single mixing; and • no dust generation. Their physical properties are listed in Table 1. Michem Guard 349 Nonionic/APE-free 50 570 25 7.3 1 Michem Guard 350 Nonionic/APE-free 50 570 20 7.0 1 Submitted by Michelman, Cincinnati, OH 46 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

For optimal viewing of this digital publication, please enable JavaScript and then refresh the page. If you would like to try to load the digital publication without using Flash Player detection, please click here.