What are epoxy resins and what is it made of?

Nick Shushan
By Nick Shusan , Epoxy Expert and the CEO of NYC Epoxy Flooring.

June 14, 2022

Epoxy resins are arguably one of the best adhesive materials nowadays. Its strongness makes it a good material for many industrial and consumer goods. The materials, quantity, and formula used for its production depend on the manufacturer and the quality of adhesiveness that is desired. Nevertheless, epoxy resin will contain a minimum of two epoxides, hardeners, and polymers from monomers. Check out this article for more information. 


What are epoxy resins?

It is better to start by explaining that epoxy is different from epoxy resins. The difference between these chemicals is very simple. Epoxy resins, also known as polyepoxides, in the uncured state comprise a minimum of two epoxide properties and they belong to the class of reactive prepolymers and polymers. These properties are responsible for the special properties of epoxy resins such as the strong adhesive ability and chemical reaction.

Epoxy resins can exist in different forms. For instance, it could be in liquid, solid, or solvent form. It could exist in solid form when it is under normal room temperature. The application of heat could make it transform into a sticky liquid. These specialized properties make epoxy resins useful in the production of both industrial and consumer products. For industrial usage, you can use epoxy resin to bond metals. Some industries prefer to use it as an alternative to welding metals. 

On the other hand, you can only get epoxy when the epoxy resin has been cured. This implies that the epoxy resin has reacted after the use of curing agents. There are different curing agents but the common one is the use of amides and polyamides. Nevertheless, you can still refer to both the cured and uncured as epoxy resin.


What are they made from?

The first thing to note here is that epoxy resins contain epoxide groups and it belongs to the class of reactive polymers. It could be reacted through cross-linking with another epoxy resin or other co-reactants such as alcohols, acids, polyfunctional amines, and many more. The co-reactants could also be referred to as hardeners. Catalytic homopolymerization is needed to make epoxide resins react among themselves. The process of cross-linking could also be referred to as curing.

In most cases, epoxy resins are produced after the reaction between bisphenol-A (BPA) and epichlorohydrin (ECH). Other materials such as aliphatic glycols and phenol could be used to replace the bisphenol-A (BPA) chemical in the reaction.

Since epoxy resins exist in different forms such as liquid or solid, the process of producing them could be different also but with similarities since the components are the same. Its production usually begins when bisphenol-A (BPA) and epichlorohydrin (ECH) are charged with the use of a reactor. Afterwards, a solution of caustic soda that ranges from 20% to 40% will be added to it. while the solution is approaching the boiling point.  

While boiling the solution, the unreacted epichlorohydrin (ECH) will evaporate. An inert solvent is then added to the solution to separate the phases. The next step is to wash the resin with water, and then the solvent in the solution will be extracted by vacuum distillation.

Due to differences in production goal and the marketability of the product, the producer of the epoxy resin will create a distinct formula by adding some additives to it. These additives will account for the difference in the ability of the epoxy resin. Such additives could be coloring, flexibility, adhesive capability, and others.

Converting epoxy resins to hard materials requires that you use a hardener to cure the resin component. The type of curing agents used will also determine the curing temperature. The temperature usually ranges from 5⁰C to 150⁰C. To meet the right temperature, most industries rely on the use of expensive ovens. Cold temperature is usually required while storing the chemical. Among many other curing agents, the combination of amides and polyamides is still the most common.


By now, you should understand what epoxy resin is and what it is made from. Nevertheless, you can still make use of it for any purpose you desire. Irrespective of what you use it for, just make sure that you are careful.