Epoxy and polyester resins, the differences of which we will consider in this article, belong to the class of thermosetting. This means that after the solidification process they can no longer be returned to a liquid state. Both compositions have different characteristics, which determines the scope of their application. To understand the purpose of these materials, it is useful to read the overview of polyester and epoxy resins.
Epoxy resin
Epoxy is a synthetic material. In its pure form, it is unsuitable for use, since it is not capable of independently transitioning to a solid state. For hardening, a special hardener is added to the epoxy resin in the desired proportion.
For proper use, you need to know the pros and cons of epoxy. This type of resin is appreciated for its strength characteristics. It is resistant to aggressive chemical compounds such as acids and alkalis. The advantages of epoxy include: moderate shrinkage, high wear resistance, and excellent strength. The solidification process takes place over a wide range of temperatures, but the recommended range in everyday life is from +18 to +25 degrees. The hot curing method is used in the manufacture of products of increased strength, able to withstand extreme loads.
This type of resin is used both in industry and at home. The scope of their use is becoming wider thanks to the creation of new compounds with optimized properties. By mixing different types of epoxy resins and hardeners, you can get the final product with completely different characteristics.
Epoxy resin
Epoxy resin is primarily used as a material for bonding surfaces: wood, leather, metal and other non-porous. Such a composition is in demand in electronics, engineering and aviation. Fiberglass, actively used in construction, is also made of epoxy. Resin is used for waterproofing floors and walls, including external ones. Fiberglass finished products after grinding and additional processing are popular in decorating the interiors of premises.
Epoxy Hardener
Epoxy material consists of two components, after mixing which the polymerization process begins. The curing component of the epoxy is called a hardener. Depending on the use of various resins and hardeners, completely different epoxy mixtures can be obtained.
The proportion of hardener in the composition may be different and depends mainly on the brand of resin. The polymerization of the epoxy resin is irreversible, that is, it is not possible to melt the already frozen material.
It is a mistake to assume that when the amount of hardener is overestimated, solidification will pass faster. An effective way to speed up the process is to increase the temperature of the mixture. Increasing the operating temperature by 10 degrees allows you to speed up the process by 3 times. Special components are available for these purposes. There are also epoxy mixtures that harden at low temperatures.
Incorrect selection of the amount of hardener adversely affects the quality of the finished product. First of all, its strength and resistance to chemicals are reduced. With a small amount of hardener, the consistency of the part becomes sticky, with excess polymer is released on the surface of the material. The most common resin / hardener proportions are 1/2 or 1/1. Before mixing, it is recommended that you read the instructions for the correct ratio of components.
Polyester resin
Such a resin is formed during the processing of special-purpose alcohols. The basis of the material is polyester. Specialized solvents and inhibitors are used to speed up the hardening process. Depending on the scope of the material, it may have a different structure and properties. The resulting product needs additional processing aimed at increasing protection against water and ultraviolet radiation. Additional coating also enhances the strength characteristics of the product. Polyester resin, unlike epoxy, is characterized by low mechanical properties. But at the same time, polyester is distinguished by a low price, due to which the material is more popular.
Such resins are actively used in the construction of buildings, in the automotive industry, shipbuilding and the production process of containers for chemical compounds. The polyester components when mixed with glass form high strength compounds. Thanks to this, the resulting material is used in the manufacture of canopies, roofs for buildings and lighting fixtures.
Polyester resin is also part of the artificial stone. Plastic made using this component is used in the manufacture of window sills, shower cabins, partitions and decorative elements. Polyester resins, unlike epoxy resins, are easy to stain.
The main advantages of polyester resin
Polyester resin, unlike epoxy, has more practicality. After mixing with glass, the composition acquires strength characteristics that exceed the properties of steel. To harden the polyester does not require special conditions and temperatures. Work with it is considered less laborious, and the material itself is cheaper.
What is the difference?
When asking the question: “Which is better, polyester or epoxy?”, You need to understand why and where the resin is needed. Both materials have their pros and cons, and the final choice depends on the conditions of use, as well as the type of surface on which the resin will be applied.
Epoxy has a higher cost, but it is more durable. Possessing excellent adhesive properties, firmly joins surfaces of various structure. Epoxy resin differs from the polyester product in slight shrinkage, better mechanical characteristics, as well as resistance to wear.
At the same time, unlike polyester, epoxy needs more time to solidify, which slows down the process of manufacturing parts from this material. Work with such a resin is accompanied by increased safety measures: when working with liquid material, gloves are required, and a respirator is required to handle a solid product. The danger is not so much the resin itself as the components used to give it a solid state. When hardening in high temperature conditions, there is a chance to lose the viscosity of the material, which creates additional difficulties in work.
Which resin is better, epoxy or polyester? Reviews say that in most cases the first is used in the form of glue, since its properties are much higher than that of a material based on polyester. In other situations, it seems more rational to use a polyester resin, which, firstly, will save, and secondly, will simplify the work.
Benefits of Using Polyester
The polyester does not emit toxic elements, is convenient to use, and special knowledge for working with it is not required. The composition is used to cover various surfaces, followed by treatment with a tool that increases strength. In terms of adhesive properties, polyester is significantly inferior to epoxy, and it is irrational to use it for gluing surfaces. As a material for decorative products is not suitable, as it has low mechanical properties. When mixing a polyester compound, a small amount of catalyst is used. The material hardens quickly, within 2-3 hours.
The finished part has elasticity and resistance to bending. The disadvantage of a polyester resin product is flammability. It is forbidden to apply polyester resin on a product made of epoxy. It is better to use it to repair a product made of epoxy material.
How to prepare the surface
Resin should only be applied to a previously prepared surface. The first thing you do with a solvent is degreasing. After removing contaminants and traces of grease, the grinding process is carried out. The upper layer is removed from the surface of the material with sandpaper or a special tool. Then the dust removal process is carried out. After this, you can begin to apply the working component.
Safety precautions
In order not to harm health when working with resins and hardeners, it is necessary to take all precautions to the maximum. Failure to follow simple guidelines can result in skin damage, burns, or lung malfunction when working with epoxy or polyester resins. Safety features when working with chemicals:
- Do not use containers intended for cooking.
- All manipulations must be carried out in special clothing and gloves. Before carrying out work, a protective cream should be applied to the hands. Grinding of finished products is carried out in a respirator and special glasses.
- If tar gets on your skin, wash it immediately with soap or alcohol.
Manipulations with epoxy components should be carried out in a well-ventilated area.