AROLON 6436 Product Code: Acrylic Polyol

Transcription

1 March 216 Product Code: Acrylic Polyol DESCRIPTION is an acrylic polyol resin designed for high solids, high performance polyurethane coatings. Low VOC (42 grams per liter) polyurethane coatings can be easily formulated with standard aliphatic isocyanates. has a high equivalent weight for economy in use. APPLICATION Industrial maintenance topcoats Light industrial topcoats OEM Coatings Railcar topcoats Off road equipment FEATURES High gloss High distinctness of image (DOI) Economical coating formulations Good chemical resistance Good weathering propertie TYPICAL PROPERTIES Percent Solids, Weight 7. Percent Solids, Volume 68. Viscosity at 25C, Stokes 1 APHA Color, maximum 1 Pounds per Gallon, Solution 8.9 Flash Point Hydroxyl Value, Solids 1 Hydroxyl Equivalent Weight, Solids F Hydroxyl Equivalent Weight, Solution 8 Solvent PM Acetate STORAGE Store in a cool, dry place, preferably under 8F to ensure maximum useful shelf life of one year. SAFETY Read the Safety Data Sheet before handling, storing, or using this product P.O. Box Research Triangle Park, NC USA Swabia Court, Durham, NC USA

2 SUGGESTED FORMULATIONS Component A 42 g/l VOC White High Gloss Topcoat Formula # Lbs. Gals. Material Disperbyk-163 (1) Methyl n-amyl Ketone Ti-Pure R-96 (2) Sand mill to a 7 N.S. Hegman. Then let down with: Tinuvin 292 (3) Tinuvin 113 (3) % Modaflow 2 in Xylene (4) % CAB in PMA (5) % T-12 in 2,4-pentanedione (6) Methyl Amyl Ketone Methyl Ethyl Ketone Part A Total Component B Tolonate HDT (7) Methyl Amyl Ketone Part B Total TOTAL COMPONENTS A + B Analysis: 1.25 Weight, Pounds per Gallon 66. Percent Solids, Weight.65 Pigment/Binder Ratio 17. Percent PVC 1./1. NCO/OH 3.5 VOC, Pounds per Gallon 42 VOC, Grams per Liter.175 Percent Tin (DBTDL) on Total Resin Solids Suppliers: (1) BYK (2) DuPont (3) BASF (4) Allnex (5) Eastman (6) Air Products (7) Vencorex Component A 34 g/l TBAc Based White Topcoat Formula # Lbs. Gals. Material Disperbyk-163 (1) Methyl n-amyl Ketone Ti-Pure R96 (2) Sand mill to a 7 N.S. Hegman. Then let down with: Tinuvin 292 (3) Tinuvin 113 (3) % Modaflow 2 in xylene (4) 1% CAB in PM (5) Acetate 5% Metacure T-12 in 2,4- (6) pentanedione T-Butyl Acetate EEP Part A Total Component B Desmodur N33 (7) T-Butyl Acetate Part B Total TOTAL COMPONENTS A + B Analysis: 1.5 Weight, Pounds per Gallon Percent Solids, Weight Percent Solids, Volume Pigment/Binder Ratio Percent PVC 339 VOC, Grams per Liter 2.83 VOC, Pounds per Gallon NCO/OH Percent Tin (DBTDL) on Total Resin Solids Suppliers: (1) BYK (2) DuPont (3) BASF (4) Allnex (5) Eastman (6) Air Products (7) Covestro Page 2 of 6

3 Gloss Gloss TYPICAL PERFORMANCE DATA 42 g/l VOC White High Gloss Topcoat Cold Rolled Steel Formula # Gardner Dry Time, hours Set.5 Through 3. Hard 4.25 Impact (Direct/Reverse) 16/16 Pencil Hardnes 2H Zapon Dry, hours g g 5. 5 g 6.5 Chemical Resistance, 24 Hour Spots, covered 5 = No Effect; 1 = Film Destroyed 1% Sulfuric Acid 5 1% Acetic Acid 4 1% Sodium Hydride 5 Xylene 4 Diesel Fuel 4 Gasoline 4 Gloss (6 /2 ) 92/85 DOI 1 WEATHERING RESISTANCE Xenon Arc Weatherometer Exposure kj Exposure 2 Gloss 6 Gloss QUV-A Exposure Hours 2 Gloss 6 Gloss Page 3 of 6

4 ISOCYANATE TO HYDROXYL RATIO (NCO / OH) FORMULATION GUIDELINES The ratio of NCO / OH used is very important in polyisocyanate / polyol coatings (polyurethanes) to maximize performance properties. Typically a 1% stoichiometric excess of isocyanate is recommended due to the isocyanate reacting with water from solvent, pigment, or air, and forming urea linkages. NCO / OH ratios greater than 1.1 / 1. provide for increased chemical resistance while lower levels offer better economics at lower performance. ACCELERATORS It sometimes becomes necessary to speed up the cure of two component urethane coatings. This can be especially true in high solids, where dry time can be quite sluggish. These accelerators will reduce the pot life and should only be used as needed. Organotin catalysts are preferred over amine catalysts, since they don t affect pot life as drastically. The most commonly used organotin compound is dibutyltin dilaurate. Use levels are dependent on desired dry times and pot life properties. Other types of accelerators are tertiary amines like Desmorapid PP (Covestro) at.2-.5% on resin solids or zinc carboxylates (8% zinc octoate up to.2% on resin solids). Carboxylic acids, such as acetic or formic acid, reduce the effectiveness of tin catalysts and therefore inhibit the reaction, resulting in longer pot life. As the acid evaporates, the reaction in the film proceeds as normal. 2,4- pentanedione will chelate with the tin compound and also increase pot life without adversely effecting the film cure. Page 4 of 6

5 Viscosity, #3 Zahn Dry Time, Hours Hours The following two graphs show the effect of different levels of dibutyltin dilaurate on dry time and pot life for. % Tin vs. Zapon Tack-Free Dry Time, g % Tin Pot Life vs. DBTDL Level Hours Page 5 of 6

6 PIGMENTATION Most pigments used with conventional urethane systems are suitable for use with high solids coatings. Typical pigments include phthalocyanine blues and greens, titanium dioxide, toluidine red, etc. Fillers and extenders include calcium carbonate, silicas, barium sulfate, wollastonite, and talcs, with the most beneficial (least durability degradation) being barium sulfate and wollastonite. Some pigments such as zinc oxides, zinc phosphates, some organic pigments and certain types of carbon blacks may act as a catalyst and reduce pot life. Pigment volume concentration (PVC) is also important in formulating high solid coatings, just as it is in conventional coatings. Usually a high PVC (around 4-45%) provides faster dry. Gloss can be maximized by reducing the pigment/binder ratio and also by using flow and leveling additives. SOLVENT SELECTION As with conventional systems, the solvent blend should consist mainly of oxygenated solvents (ketones or esters). Aromatic solvents, such as toluene and xylene, are not active solvents for acrylic polyurethane systems, but have good latent solvency when used in blends with other solvents. Special anhydrous grades of solvents such as MAK (methyl n-amyl ketone) and PM Acetate are usually required. The water content of the solvent blend used in the polyisocyanate should not exceed.5% (5 ppm). Alcohols and glycol ethers are not recommended because of their ability to react with the isocyanate. ADDITIVES Most additives used with conventional coatings are suitable for high solid coatings. Since low VOC coatings tend to be heavier (more viscous) and fluffier than conventional systems, defoamers are even more important for release of air during both pigment dispersion and application of the coating. Suitable defoamers include BYK-77 and also 1-2% mineral spirits. Suitable flow-control agents include surfactants, such as Anti-Terra-U (BYK) and Nuosperse 657 (Elementis), silicone and acrylic resins, such as Modaflow (Allnex), and amino resins (urea formaldehyde). Bentone clays, colloidal silicas, and castor based thixotropes (such as Bentone SD-2 and M-P-A 6 X, both from Elementis) are all employed for sag resistance and pigment suspension. Since isocyanates react with water (OH groups) the incorporation of a moisture scavenger is a recommended, especially for high build systems. The isocyanate can react with water from the pigment or solvent, and also with water condensed onto the paint droplets as it is atomized and sprayed. Solvent evaporation causes cooling, which results in moisture condensation. Moisture scavengers include molecular sieves and triethyl ortho formate. Page 6 of 6