Paint & Coatings Industry - May 2008 - (Page 57)

Dispersants for and Inks To test these esters, dispersions were again made with the same red, blue and yellow pigments. In addition, the foaming and defoaming characteristics of the SMA ester solutions were tested. Lastly, the VOC of the esters was measured. VOC Test Since many paint and ink formulators are concerned with the VOC of their ingredients, the VOC of each SMA ester was measured by placing 1 g of each in an aluminum pan and heating for one hour at 110 o C, then re-weighing the pan to determine TABLE 1 | SMA alkyl esters with hydrophobicity indices ranging from 66.5 – 77.1. Experimental Raw materials Dispersion formulation ingredients: • Lithol Rubine pigment = LR 1392 – Magruder Color Company • Phthalo Blue Pigment = BW 1531 – Pacific Coast Enterprises • Diarylide Yellow pigment = Ciba Yellow BAT – Ciba Geigy • Defoamer = Byk 022 – Byk Chemie • SMA Ester resins = Sartomer Company, Inc. Ink formula ingredients: • Solution acrylic resin - Joncryl 63 – BASF Corporation • Letdown acrylic emulsion = ECO 2177 – BASF Corporation S:MA 1:1 2:1 3:1 4:1 1:1 2:1 3:1 4:1 1:1 2:1 3:1 4:1 1:1 2:1 3:1 4:1 Alkyl alcohol n-propanol n-propanol n-propanol n-propanol 2-ethyl hexanol 2-ethyl hexanol 2-ethyl hexanol 2-ethyl hexanol lauryl alcohol lauryl alcohol lauryl alcohol lauryl alcohol stearyl alcohol stearyl alcohol stearyl alcohol stearyl alcohol Hydrophobicity Index 62.0 73.2 79.4 83.1 66.5 75.5 80.8 84.1 69.5 77.1 81.8 84.8 73.0 79.2 83.1 85.7 Foaming/Defoaming Test The foaming characteristics of SMA ester solutions are important because if too much foam is generated during the high-shear dispersion process, this will decrease the dispersant efficiency to wet the pigment agglomerates, resulting in lower color development. Also, if too much air is entrained, then the rheology of the dispersion will be difficult to handle during the letdown stage. To test the foaming/de-foaming characteristics, solutions of each dispersant were made at equal solids, and 125 mL of each solution was placed into a graduated cylinder and corked. Each cylinder was then rotated 10 times. As soon as the rotations stopped, each cylinder was placed on a flat surface, the initial volume recorded, and a timer was started. The foam levels were then checked at 30, 60 and 300 seconds. Foam height values for each of the solutions are plotted versus time after mixing (Figure 2). Zero foam is at 125 mL, which is the liquid level. Note the high levels of initial foam at zero seconds, and sustained foam with both commercial SMA esters A and B. However, with each of the new esters the initial foam levels are much lower, and the foam breaks more quickly. TABLE 2 | Hydrophobicity indices of SMA esters made with different types of alcohols. Ester NTX7633 NTX7634 NTX7635 NTX7636 NTX7637 NTX7638 NTX7639 NTX7643 Ester A Ester B Hydrophobicity Index 72.6 70.7 71.4 72.6 73.2 73.2 72.7 74.9 74.3 71.1 TABLE 3 | VOC content of SMA esters. SMA ester Ester A Ester B NTX 7636 NTX 7638 NTX 7639 NTX 7643 Weight % VOC 3.51 1.08 3.19 4.12 1.27 3.29 57 PA I N T & C O A T I N G S I N D U S T R Y

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.