The word "epoxy" is known to almost everyone. But the epoxy resin, the use of which is quite common today, is a type of synthetic resin. She appeared in the 50s. of the last century and immediately gained popularity due to its universal properties.
Today, epoxy resins are used in industrial production and households. Possibilities of application are constantly expanding due to the development of compositions with improved characteristics.
Epoxy Description
In terms of chemical composition, epoxy resin is an oligomeric synthetic compound. These materials are in demand today in almost all areas of industry. In its free form, epoxy is not used, but in combination with a hardener, it is able to exhibit unique properties after the polymerization reaction. If the epoxy resin is combined with curing agents, then it can turn out:
- hard solid materials;
- soft and durable products;
- rubber-like materials.
Epoxy resins are resistant to the following substances:
However, dissolution occurs in esters and acetone without film formation. After curing the epoxy resin, its composition does not emit volatile substances, and shrinkage is negligible.
Features of the dilution of epoxy
If you wondered how to dilute the epoxy resin, you should know that a lack or excess of hardener in the composition can adversely affect the quality of the polymer, while it remains resistant to heat, but its strength decreases, and its ability to counteract chemicals and water is preserved. . If the hardener is not added in sufficient quantity, the product may be sticky due to unbound resin.
Before you dilute the epoxy resin, you need to understand that the excess free hardener is released on the surface of the polymer during operation. To obtain different compounds, curing components and resin are used in different proportions, this can be found in the instructions. If we are talking about a modern compound, then the ratio most often looks as follows: 1 to 2 or 1 to 1.
Epoxy Dilution Guidelines
Today, there is an opinion that when using a hardener in a volume greater than normal, the polymerization reaction will occur faster. These thoughts can be considered a delusion. The easiest way to speed up the process is to increase the temperature of the reacting mixture.
If you want to speed up the process three times, then the temperature should be increased by 10 ° C. If you are thinking about how to dilute epoxy, you should know that today special compounds are known that contain curing accelerators. You can find commercially available and epoxy compounds that solidify at low temperatures. The type of hardener and the temperature of the mixture are the main factors that affect the polymerization rate.
Dilution of epoxy resin: compositions with different polymerization temperatures
Epoxy resin can be cured at temperatures ranging from -10 to +200 ° C, everything will depend on the type of composition used. Hot and cold cured resins are known today. Cold type hardener and epoxy are most commonly used in everyday life. You can meet such a composition in the conditions of production with low power, as well as where heat treatment is unacceptable.
To obtain high-strength products that will be able to undergo high loads and temperatures, as well as exposure to chemicals, curing components of the hot type are used. During hot polymerization, a dense network of molecules is formed. There are also compounds and their oxides that are capable of polymerizing in sea water and in a humid environment.
Application area
Epoxy materials today are distributed throughout the world, they are known from the middle of the last century. The nature of the use of these materials in recent years has undergone significant changes, however, the use remains traditional in several areas, among them:
- fiberglass and glass fiber impregnation;
- waterproofing coating;
- creation of chemically resistant coatings;
- manufacture of transparent solid material for fiberglass products.
Epoxy resin, the use of which is quite common today, can act as an impregnating agent for bonding parts in electrical engineering, automotive, aviation, radio electronics and industry. In this case, the composition is used in the production of fiberglass in machine and shipbuilding, construction, in workshops for the repair of car body elements and boat hulls.
Work with epoxy resin is carried out where there is a need to waterproof the walls, as well as the floors of basements and pools. Using epoxy resin, it is possible to produce materials and paints for exterior and interior decoration of buildings, as well as impregnation, which will provide waterproofing of porous materials and their increased strength, among them wood and concrete should be highlighted.
For reference
Epoxy resin can form the basis of a transparent solid material, which is carried out by pouring into a mold. At the next stage, the products are processed mechanically, such as grinding and cutting. It is used for fiberglass products in design work, electronic industry, construction and household.
Working with epoxy: surface preparation
Working with epoxy resin requires the preparation of the surface before applying the composition. Only then will high-quality adhesion be achieved. Therefore, before you dilute the epoxy resin, first prepare the surface. To begin with, the base degreases. There should be no traces of oil products or grease on the surface. The surface is cleaned using solvents or effective detergents. It is important to make sure that there is no gloss.
The top layer is removed by grinding. Small surfaces must be prepared manually; use sandpaper to do this. Impressive over the area of the base are processed by grinders, and the resulting dust should be removed with a vacuum cleaner. In the manufacture of fiberglass or layer-by-layer laying of epoxy self-leveling floors, varnishes and paints, each subsequent coating must be applied to a not yet completely frozen, still sticky previous layer.
If the technology and requirements for the finished product allow, then the lower layer, which acts as a substrate, should be sprinkled with fine sand. After hardening, excess sand will need to be removed and a new layer of epoxy applied.
Preparing a large volume of epoxy
If you are not aware of the specific properties of epoxy resin, then you may encounter problems in the manufacture of material in large volumes. As epoxy volume increases, more heat is generated. When boiling, the resin will foam, become dull white. This composition cannot be considered suitable for use. Diluents and solvents may be added to the resin to reduce viscosity. Even a small concentration of them can cause a decrease in the strength and heat resistance of the product. The result is sweating of the diluent from the polymer, which entails a deterioration in the quality of the material.
Epoxy resins and hardeners must not contain water. If this happens, the composition will become cloudy and lose its properties. Today, a water-borne epoxy is produced. Such formulations are diluted to achieve dispersion with distilled water. Two-component epoxy must be mixed with a plasticizer. The resulting mixture is slowly heated, which is true if DBP is used. When using DEG-1, the composition must be mixed.
For thorough mixing, use a special nozzle on a drill or construction mixer. The proportions of the resin and plasticizer are selected depending on the required ductility, but most often the proportion of plasticizer varies from 5 to 10%. Hardener is added to the mixture. The resin cools to +30 ° C to prevent boiling. The standard proportion of resin with hardener looks like 1 to 10. To achieve uniform dissolution of the hardener, mixing should be ensured. Otherwise, the composition will turn out to be heterogeneous, and subsequently will sweat.
Resin Crafts
Quite often, craftsmen perform epoxy crafts. These works may be accompanied by certain difficulties. The product should be transparent, there should be no air bubbles inside it. In the thickness and on the surface, curing should be uniform. If the thickness is more than 2 mm, then the material is applied in layers after the initial polymerization. Resin can be poured into molds. In order for the product to separate, the mold is lubricated with technical petroleum jelly or fat.
Dye for epoxy will give the product any color. After completion of work, the product is kept at a temperature slightly above room temperature. After 3 hours, primary polymerization will begin, curing before sticking, after which the product must be warmed up to accelerate the curing process for 6 hours. If you decide to do crafts made of epoxy resin, then, quite possibly, you will not be able to use a special oven.
At room temperature, the polymerization will last 2 weeks. If triethylenetetramine is added to the ingredients, the surface may remain sticky. The molded product must subsequently be machined. Domestic epoxy is not so suitable for casting massive products, because it is characterized by uneven curing of the thickness.
Epoxy Resin Coloring
The dye for epoxy will allow you to get a home composition painted in a certain color. In order to ensure uniform distribution of pigment, manufacturers use dozens of surfactants. Pigmentation can reduce the transparency of the resin, sometimes it changes color, the resin darkens. Pigment should be added before the catalyst, but after the addition of wax.
Technical characteristics of epoxy resin as an example of the composition of the brand ED-20
The epoxy resin, the characteristics of which will be listed below, is a yellow-like honey-like liquid that is easily stained. The density at 20 ° C of the external environment is the limit of 1.16-1.25 kg / m 3 . Tensile strength is 40-90 MPa. Bending strength is equivalent to 80-140 MPa. The compressive strength is 100-200 MPa.
The polymerization temperature is 20 ° C and above. If you are interested in epoxy, the proportions of the mixture when combined with the hardener should be of interest to you. The latter should be used in a volume of 7 parts, while resin is added in an amount of 1 part. The polymerization time of the composition is 1.5 hours. Water absorption in 24 hours is equal to the limit of 0.01-0.1%. Heat resistance ranges from 55 to 170 ° C. Impact strength is 5-25 kJ / m 2 .
The main properties of epoxy resin
Before deciding where to buy the epoxy resin, you should find out its basic properties. Among others, low resistance to cracking, as well as more impressive toxicity compared to acrylic resins, should be highlighted. The properties of the epoxy resin indicate that the composition is highly viscous and should be used in conjunction with solvents. To lower the viscosity of the resin, you can heat the mixture or add a solvent to it. In both cases, the resin will become more fluid. It can be applied with a roller or brush, it quickly impregnates fiberglass and penetrates into porous surfaces, such as wood.
Conclusion
Quite often, consumers wonder where to buy epoxy. Today, this material is offered by many companies, among others the composite supermarket Karbo, which is located in Moscow at 42 Volgogradsky Prospekt, should be highlighted.