Epoxy resin - a substance that is highly resistant to acids, halogens and alkalis. This is a synthetic oligomer. With it, you can glue almost any material. In the liquid state, it is a transparent epoxy resin with a yellow-orange color, and after hardening it becomes brown and practically safe for health. However, it cannot be used where there may be potential contact with solvents leaching sol fractions. In the liquid state, it is very toxic, so its use requires compliance with a certain set of rules.
Of course, it is impossible to use it for gluing dishes or other objects in contact with food or drinking water, for this there are other substances. However, due to its properties, epoxy resin is an indispensable tool in a very wide range of industries. Two main ways of using this material: as an adhesive and impregnation. With its help, concrete, metal are protected from corrosion, molds are made, various, even very important, parts are glued together in almost all engineering industries. Epoxy resin and fiberglass are the starting materials for the production of fiberglass, widely used in construction, shipbuilding and aircraft manufacturing. Also, the first is used for filling in electronics and even in design.
Epoxy resin is used in conjunction with a hardener. Where heat treatment is unacceptable, cold substances are used in small workshops in domestic conditions. And for important products designed to work under high static and dynamic loads, in aggressive environments - hot curing reagents. In this case, a denser network is formed that holds together the polymer molecules. In addition, there are epoxy resins and hardeners designed specifically for conditions of high humidity, salt water.
When working with it in everyday life, it is necessary to understand that when it is combined with a hardener, an exothermic reaction occurs, and the greater the mass of the polymer, the more heat is generated. In this regard, it is necessary to choose the right amount of substance and correlate it for the purpose of use, since in the end a uniform (without bubbles) solid substance should be obtained. In addition, the reaction of the hardener and the resin is irreversible, and after it, the thermoset, unlike thermoplastics, cannot be melted or dissolved to alter the result.
The most common and available substances for curing epoxy materials today are PEPA, DETA, TETA, TEPA and No. 1 (hexamethylenediamine dissolved in ethyl alcohol). Due to the fact that the usual two-component compound is a rather fragile thing, its elasticity is increased by adding one more component. This element is called "elasticizer", it can have a different chemical composition and, depending on this, have certain characteristics. True, chemists have already discovered materials that have the ability to simultaneously act as both a hardener and an elasticizer.