Epoxy Paints come in lots of flavors:
Epoxy is a copolymer; that is, it is formed from two different chemicals. These are referred to as the "resin" and the "hardener".
The resin consists of monomers or short chain polymers with an epoxide group at either end. Most common epoxy resins are produced from a reaction between epichlorohydrin and bisphenol-A, though the latter may be replaced by similar chemicals.
The hardener consists of polyamine monomers, for example Triethylenetetramine (TETA). When these compounds are mixed together, the amine groups react with the epoxide groups to form a covalent bond. Each NH group can react with an epoxide group, so that the resulting polymer is heavily crosslinked, and is thus rigid and strong.
The process of polymerization is called "curing", and can be controlled through temperature, choice of resin and hardener compounds, and the ratio of said compounds; the process can take minutes to hours. Some formulations benefit from heating during the cure period, whereas others simply require time, and ambient temperatures.Epoxy Paints come in lots of flavors:
The purpose of this page is to get you up to speed about epoxy paints and to compare the different types of Epoxy Paints.Epoxy Paints:
What separates general purpose epoxy paints (and non-epoxy paints) for epoxy and non-epoxy floor paints, plain marine resins, or even water, is their thixotrophic properties. The term has to do with internal gelling of the paint. Thixotrophic additives, such as fumed silica, give the coating the ability to 'gel' after application. This means when applied to a vertical surface, such as a wall, the coating will be as thick at the top of the wall as it is at the bottom of the wall.
Regular marine epoxy, floor paints/epoxies, and water, are non-thixotrophic and if applied to a wall would tend to flow or slump to the bottom of the wall, leaving very little of the coating near the top of the wall. The advantages of epoxy paints is that they can handle full time immersion, strong chemicals, and are very impermeable as well as tough. Many are solvent free so wet thickness will equal dry thickness (cracks will not reappear as the epoxy cures) and they are nearly odorless. Some can even be applied underwater.
The disadvantages of epoxies are that they tend to be brittle, quickly yellowing sunlight (white becomes a creamy color, light blue becomes light green, etc.) and lose their shine in sunlight. The yellowing and loss of gloss (even chalking in some cases) is due to the affect of UV on ALL epoxies (some epoxies will yellow in days, others take weeks but they all do eventually).The major differences between the different epoxies are:
Color - although in large volumes (15 - 60 gallons depending upon the formulator) custom colors are usually available - but remember that epoxies yellow. Generally our epoxy paints are available only in one color, which varies from product to product.Viscosity/Fillers
Solvent free epoxies tend to be somewhat thick, but all the epoxies considered here are rollable or brushable. Some are thinner than others making them slightly easier to brush or spray apply. Some epoxy's contain both Kevlar (tm) microfibers and feldspar ceramic which complicates things if the product is to be spray applied. Generally many of these products can be applied at up to about 20 or 25 mils by brush or paint pad, however if applied by paint roller coating thickness is generally about 6-8 mils because the back side of the roller tends to lift (remove) a lot of the epoxy that the front end of the roller puts down. Note that at 16 mils coverage is 100 square feet per gallon - at 8 mils it is 200 square feet per gallon.Potlife
The amount of time after the two epoxy components are combined that they can be used before they begin to harden. Potlifeis greatly affected by temperature (doubling or halfing every 18 degrees F or 10 degrees C) and by the amount and concentration of the epoxy. 12 ounces of epoxy in a cup will have a much shorter potlife than 12 ounces spread out on a floor or 3 ounces of epoxy in a cup. In really hot weather an epoxy with a long potlife may be necessary because an epoxy with a more 'normal' potlife may not provide enough working time (perhaps only 10 minutes or so). In cold conditions a 'fast' or short life epoxy may be necessary because the cold conditions will greatly slow down the epoxy reaction and stretch out the potlife considerably.