Epoxy 101: What is Epoxy?
What is Epoxy? Definition and Synonyms
Ask the question “What is epoxy?” and you will find multiple definitions from a variety of sources. Epoxy is so widely used by many industries, that its definition varies slightly based on the application.
Definition of Epoxy:
- Epoxy is a class of resin derived by polymerization from epoxides. Epoxies are used chiefly in adhesives and coatings.
- Epoxy is a thermosetting resin capable of forming tightly linked cross-polymer structures.
- Epoxy is characterized by toughness and strong adhesion, especially when used for floor coatings.
epoxy resin, epoxy polymers, epoxy coating, epoxy paint
What is an Epoxy?
Epoxies are polymer materials that begin as liquids and are chemically changed into a solid. An epoxy based polymer is mechanically strong, chemically resistant to degradation from chemical elements in the solid form, and highly adhesive during conversion from liquid to solid. There are a wide range of basic epoxy chemicals from which an epoxy coating system can be formulated.
What are epoxies? Physically epoxy coating systems contain two components, resins and hardeners. The resin component is usually light, sometimes almost clear colored, and almost odor free. Hardeners are usually dark and have a slight odor. When these two components are mixed, they will chemically bond together, and once the chemical reaction has finished, they will form a strong and rigid plastic material.
This Epoxy 101 guide answers the question: What is Epoxy? For additional information on using epoxies, see: Working with Epoxy Coatings
Why use an Epoxy?
Epoxy coatings are used because of their outstanding chemical resistance, durability, low porosity and strong bond strength. Epoxy coatings can be formulated to be field applied, brushed-on, rolled-on, or troweled-on.
Epoxies are known for their excellent adhesion, chemical and heat resistance, good-to-excellent mechanical properties, and very good electrical insulating properties.
What are epoxies used for? Applications of epoxy based materials are extensive and include: coatings (i.e. epoxy floor coatings or anti-corrosive coatings), adhesives and composite materials like carbon fiber and glass-reinforced plastic (although polyester, vinyl ester, and other thermosetting resins are also used for glass-reinforced plastic). There are even special epoxy coating formulations that offer increased chemical resistance, increased temperature resistance, and the ability to be applied underwater.
What is Epoxy? Epoxies Make Great Floor Coatings:
While epoxy floors are very common, for serious and demanding applications the epoxy is either mixed with, or applied under and above, quartz (sand) or aluminum oxide grains. Either way, the result is really a quartz or aluminum oxide floor, held in place with the epoxy. The quartz, and even better the aluminum oxide, is much more durable and wear resistant than the epoxy alone.
Adhesion of Underwater Applied Epoxies:
Underwater epoxies generally have good-to-excellent adhesion to most submerged surfaces (i.e. emergency boat hull repair); however, steel surfaces in saltwater environments can be a problem. Such surfaces are often protected by a cathodic protection system. These systems use electrical current to suppress corrosion. Dissimilar metals in saltwater also form tiny electrical cells. Because epoxy bonding is due to molecular attraction of charged particles, existing electrical charges, known or unknown, can interfere or disrupt epoxy bonding. It is best to test underwater coatings for possible cathodic adhesion problems if used in marine settings on steel surfaces.
How Much Does Epoxy Cost?
The best epoxies are expensive, especially industrial strength epoxies. But there are ways to ‘water down’ epoxies with less expensive solvents and/or non-solvent thinners. These cheaper, diluted epoxies do not perform as well as the more expensive, unaltered epoxies. Diluted down epoxies are especially common with ‘floor epoxies’ where pricing pressures are especially strong. To a large degree you do ‘get what you pay for’.
How to Identify Cheap Epoxy:
A common non-solvent thinner is a chemical known as nonylphenol. This chemical is sometimes used in small amounts to make epoxy mixing ratios easy whole numbers. However, cheap epoxies may contain large amounts of this inexpensive chemical. Check your epoxy’s MSDS for references to nonylphenol.
Another clue of a cheap epoxy is if it requires hazmat shipping. Generally, the better resin systems can be shipped non-hazmat. The exceptions are special high temperature and/or more UV resistant epoxies, which often require hazmat shipping.
Other clues of cheap epoxies include ‘induction time’ (after mixing the two components the mixture must sit for several minutes to ‘self-cook’ before being applied), and crystallization of either part A or part B, if left sitting for several months (like crystallized honey, simple heating will dissolve the crystals).
As they cure most epoxies ‘blush’. Blush is a waxy coating that forms in the surface of the curing epoxy due to moisture in the air. Because nothing sticks to the waxy coating (including paint or additional layers of epoxy) it must be washed off. Most epoxies blush to some degree but some of the very best epoxies do not.
The Problem with Solvents in Cheap Epoxies:
Adding a bit of solvent to a solvent based or solvent-free epoxy is something that most manufacturers would not officially approve of and something that might not work with all epoxies.
Most States and the EPA have regulations regarding the acceptable levels of these carcinogenic agents allowed in products due to health and environmental concerns. Not only are they a health hazardous substance, they are one of the primary causes of coating failures. As the solvents evaporate in to the air and water, the coating becomes thinner and holes are created in coating’s structure, causing permeability problems. This process continues long after the original curing process. The results are a failing coating system that will allow the penetration of harmful chemicals to undermine the coating and damage the structural base metal or concrete.
Less Expensive Polyester Resins vs. Epoxy Resins
The difference between polyester (fiberglass) resins (commonly used in fiberglass boats) and epoxy resins: Polyester resins are much less expensive, have very strong fumes, are more porous than epoxy resins, and only stick really well to themselves. For anti-blister marine barrier coatings and bonding to wood, steel, etc. use epoxy resin instead of polyester resin. Generally, epoxies (which are often solvent-free) can be applied to foam products whereas the polyester resins will dissolve these products.
The Novolac Epoxy Advantage:
Novolac technology is the cutting edge in epoxies.
- Environmentally safe (100% solids hybrid NOVOLAC systems, contains no solvents, no volatile or organic compounds)
- Superior Bonding (Bonds both mechanically and chemically to concrete and metal in excess of 3000psi ASTM D 4541)
- Higher Chemical Resistance (Due to its chemistry, this Novolac epoxy has very high chemical resistance’s, withstands up to 98% sulfuric acid)
- Higher Temperature (High Temperature engineered versions are available for service temperatures exceeding 400 °F)
- Superior Abrasion Resistant (ASTM D4060-9 testing for abrasion resistance proves that the incorporation of alumina oxide ceramic into the matrix provides excellent resistance to abrasion and improves chemical resistance)
- Reinforcing Kevlar™ Fibers (The addition of reinforcing Kevlar fibers, which are six times stronger than steel, to the epoxy matrix, tremendously increases the flexural and tensile strength by up to 5 to 6 times. This substantially increases wear resistance and greatly reduces the possibility for damage from impact to crack or chip the epoxy.)
All of our Products are:
- User Friendly
- Environmentally safe
- Kevlar reinforced
- Tested and used worldwide!
ECO-POLYMER is a new generation of hybrid 100% solids NOVOLAC epoxy coating and repair system with optional rubber, ceramic and Kevlar™ additives, providing outstanding impact resistance, great wear, excellent compressive and tensile strength, and elongation.
What is epoxy used for? Eco-Polymer may be applied to damp or wet surfaces and has proven to have outstanding resistance to gasoline, jet fuel, diesel fuel and other petroleum products. Combined with a bonding strength greater than 3000 PSI, this NOVOLAC epoxy has proven to be more than four times more effective against salts, alkalis, sewage and dilute mineral acids than traditional epoxies. ECO-POLYMER has proven ideal for protecting concrete and steel in aqueous service in water/waste management, wet wells and manholes.
Today with new curing agents, this hybrid NOVOLAC resin can be combined for ease of application by roller, brush or spray, and is safe for the applicator and the environment. These user friendly products are formulated without solvents or VOC’s, and are basically odorless, so they may be applied in occupied areas.
Thank you for reading our Epoxy 101: What is Epoxy guide. We hope this webpage has helped you to learn more about: What is an Epoxy? If you still have questions, please contact us today for more information.