Hot Rod Forum : Hotrodders Bulletin Board - View Single Post - urethane and polyurethane
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Old 12-28-2012, 08:04 AM
mluckett4410 mluckett4410 is offline
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In this forum you are talking about paint. I am a paint chemist and I do dabble a little with auto primers and clear coats. Polyurethanes can be rock hard or a elastic soft touch. Polyurethane is what you get when you mix a 1. Isocyanate with a 2. Polyol. Urethane or really polyurethanes can be acrylic, polyester,alkyd, vinyl, Nitrocellulose, cellulose acetate butyrate and on and on. All of thiese items in the second group are the polyol. Water is a polyol H-OH, this will cause CO2 bubbles in your paint. This is why there are urethane grade solvents which are very low in moisture. We also use moisture scavengers to consume water. A polyurethane can be lacquer solids of 15-20% to 100% solids. There are so many products out there and so many claims it is hard to keep it straight. Japaneses, German, and American automakers all have different approaches to clear coat hardness and they all have advantages and disadvantages. Polyurethane is the predominate clear coat chemistry hands down. Where I work we still make Nitrocellulose Lacquers just like the old days.
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