In the past weeks we have talked about pre-cats and post-cats wood coatings. We have talked about what makes a coating reactive or non-reactive. We have talked about solvent based and water borne versions of these coatings. We have talked about how acid and urea resins react with each other in solvent based coatings to create formaldehyde. Then we learned that there are now reactive solvent based coatings that release no formaldehyde at all and are Greenguard certified. You may use these coatings to gain LEED points on those jobs requiring that specification.
Now we are going to talk about water borne coatings with a little different twist. I have spoken about how this technology as the path to the future. That is true if for no other reason than the new generation of pre-cat and post-cat water bornes are so much better than the coatings that came before them and AWFS Vegas Fair gave us a look at what is on the horizon.
But, before we look at the look new generation of coatings let’s consider the slippery slope! Some of these coatings are Greenguard certified and some are not. Why? Because getting a coating certified involves more than a low VOC content. Greenguard looks at the whole “package” and decides if there are items in it that will lead to indoor air pollution. If so, then they will not certify the coating.
There’s another piece that I haven’t even mentioned yet. But I will now: Formaldehyde is the boogie man in solvent based coatings. No more needs be said there. We know formaldehyde isn’t an issue with water borne coatings because the resins used are different. No acid/urea resin reaction. But there are reactive water bornes in both pre-cat and post-cat.
Here’s the other piece of the puzzle. In some solvent based and water borne resin packages, there are two component systems (2K systems) that release a chemical called isocyanate or, perhaps, diisocyanate. These guys are used in a huge way throughout industry to produce what we call polymers. The global market in diisocyantates in the year 2000 was 4.4 million tons. As you can see, polymers are everywhere in our lives.
Isocyanates plus a hydroxyl molecule group yield a urethane molecule. Diisocyanates plus two or more hydroxyl groups (a.k.a. a polyol) yield a polyurethane. Polyurethane molecules are long, stringy things that make for a great coating.
Isocyanates and diisocyanates are a serious health hazard let alone an indoor air pollutant. That is why these isocyanate-releasing coatings are to be sprayed out in a proper spray facility. For the record, I’m NOT talking about a brush grade urethane or polyurethane spar varnish-type coating. I am talking specifically about a two component (mix it like a post-cat) 2K water borne or solvent based industrial spray product. There are also some single component moisture cured products as well.
These kinds of coating are one step up the durability ladder from “lacquers.” Those long molecule strings make a really tough coating. But until now, getting one that could be Greenguard certified was a light years away.
Are you ready? It’s here!
Aguatana by M.L. Campbell made its debut at the AWFS in Vegas this year. Unfortunately, it got overshadowed. All the buzz at the show was about zero formaldehyde release solvent coatings. EnviroVar from M.L. Campbell even won a Sequioa Award and Sherwin Williams trumpeted their new product as well. But EnviroVar stole the spotlight!
Aguatana is a two-component water borne polyurethane coating that meets Greenguard certification. No isocyanate release to ruffle Greenguard’s feathers and, from what I understand, one heck of a coating. Look for it in the months to come. We’ll talk more on this subject after I get an opportunity to spray it out and test it for myself.
Until next time…spray on!
Bernie Bottens (WoodworkingNetwork.com/blogs) teaches wood finishing in industrial woodworking to shop owners, foremen, spray technicians and finishers all over the Pacific Northwest. He is wood finishing specialist with Wurth Louis and Co., Portland, OR. Reach him at email@example.com.
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