If you are specifying products used in commercial applications, it is often useful to have a little technical information to assure your project will survive its expected lifespan. Today’s tip is an important one, as we discuss the point where “the rubber meets the road”, the furniture finish.
The typical commercial finish used today is a lacquer or varnish. Both of these finishes fall into the broad category of nitrocelulose finishes, or “N/C”. The history of N/C or “guncotton” is fascinating, and was even referenced by Jules Verne in his novels. Guncotton, cotton fibers soaked in a solution of nitric acid and sulfuric acid, was manufactured for a time as a powerful explosive used in ammunition. As it was quite unstable, particularly when exposed to moisture, it was discontinued rather soon after it was introduced.
It was discovered that combining guncotton with acetone produced a very nice wood finish, and soon cotton fibers were replaced with other types of cellulose to produce the product known as lacquer. Lacquer penetrated into the cell structure of the wood upon its application, but it was water-permeable, as anyone who has left a water glass on a lacquer finish has discovered. In addition, it does not like chemicals, such as acetone (fingernail polish remover).
Modern day “catalytic” lacquers and conversion varnishes are the standard of the industry, as they employ an added polymer that tends to make the product more water-tolerant and a bit harder than its earlier versions. They are relatively easy to apply, but the solvents used to apply the N/C fibers to the surface (which create the finish) contain high levels of formaldehyde, which is a known carcinogen. Even though the formaldehyde in the solvent flashes off in 30 to 60 days, it still is not a healthy product to place in hotel rooms.
Polyurethane finish (P/U), is the other major option for commercial furniture. This type of finish is harder, chemical resistant to such products as acetone, and waterproof (it is used on flooring, and much more durable than N/C finishes on automobiles and boats). The polymer bond forms a “plasticized” shell on the furniture that is many times more durable than N/C finishes.
But, there is a downside. P/U finishes combine two components, much like an epoxy glue, which harden in a short period of time, making the application much more difficult than N/C lacquers. In addition, it must be applied in a dust-free environment, taking up valuable space in the manufacturing environment, and adding cost to the process. Polyurethanes deliver a much thicker and harder finish, because they don’t require the amount of solvents to apply them. So, even though they do contain isocyanates (another toxic chemical for humans) in the solvent, it dissipates within an hour or two of application, creating no long term exposure.
If you find a manufacturer in the US to coat the furniture with polyurethane finish, it is generally much more expensive. John Ralph uses polyurethane on most of our products, and since we are structured to make furniture for resorts, we have invested in the equipment to assure a very long useful life for our product. You will notice the difference within the first few months of use, as there will be fewer nicks and dings, and no water or chemical issues. Find out more about these advantages on our website under Certifications & Sustainability.