What Are Epoxy Resins

All you need to know about epoxy resin adhesives

There are tons of articles on the Internet about epoxy resins, and most of them address the topic superficially rather than expertly. It is clear to everyone that epoxy resin has many applications in various industries from construction to the petrochemical, oil, power and water industries. You may also have many questions and are looking for a scientific answer to them, such as what exactly is epoxy resin? What is its chemical composition and molecular components? Or what are the properties and advantages of epoxy resin? This lack of scientific content convinced us to study epoxy resin in this article. This article is dedicated to introducing you to epoxy resin, so keep on reading.

Epoxy resin and its chemical composition

Epoxy resin was discovered in 1938 by Pierre Castan, which has many applications in various fields, such as paint, electricity, civil engineering, etc. Epoxy resin is widely used because it has a very high ability to bond with other surfaces. Additionally, it attains high mechanical strength and chemical resistance after hardening.The distinguishing feature of these resins is that they contain more than one group of 2 epoxy resin in their molecular structure. This group may be in the body of the chain or at the end.

 

The chemical composition of epoxy resin consists of two parts, epoxy and non-epoxy. The non-epoxy fraction may be aliphatic hydrocarbons, aliphatic silico or highly cyclic hydrocarbons. In practice, the product of the BPA and epichlorohydrin reaction often forms common epoxy resins. These products hold 80 to 90% of the market share.Previously,
epoxy resin was used almost exclusively as a surface coating. Before World War II, high production costs of bisphenol A and epichlorohydrine prevented epoxy resins from being marketed. Subsequent efforts and the invention of new production methods gave rise to the economic acceptance of these resins.

Properties of cured epoxy resins

Epoxy has many active functional groups and can form a network structure in the presence of curing agents and stiffeners. The properties of the hardened epoxy depend on the following factors:

  • The type of epoxy resin
  • The type and amount of hardener
  •  Crosslinking rate
  • The nature and volume of additive additives

There are many hardening agents on the market that have longevity, elasticity, fast hardening properties, and low toxicity.

The molecular structure and properties of the cured resin depend on the nature of the curing system. Although there are different curing systems, they can be divided into two groups: amines and anhydrides.

Epoxy resin and hardening agents are not the only components of the formula. For some applications, unmodified epoxy may have undesirable properties such as high viscosity, high cost, and low impact resistance in some special applications. Therefore, in most cases, it must be accompanied by substances such as thinners, fillers and reinforcers. Correct selection of resins, hardeners and additives allows to achieve the desired properties, and this diversity is a major factor in the long-term growth of the epoxy base.

Properties of epoxy resin

In addition to this versatile structure, epoxies also have the following properties:

  • Excellent chemical resistance, especially in alkaline environments
  • Good adhesion to a group of different substrates
  • Very high tensile, compressive and bending strength
  • Low shrinkage after hardening
  •  Dimensionally stable
  • Excellent electrical insulation
  • High durability in harsh environmental conditions
  • The possibility of curing at different temperatures
  • Excellent resistance to stress
  • Odorless and tasteless

Types of epoxy based on the method of hardening

Epoxy adhesives are generally divided into two groups of one-component and two-component epoxy adhesives according to the processing method.

one-component epoxy adhesives

The one component adhesives are cured after application at a temperature between 250 and 300°F and do not require a hardener. This set has excellent adhesion and shows very good resistance in adverse weather conditions.

Two-part epoxy adhesives

In addition to being able to harden at high temperatures, two-part epoxy systems can be processed at room temperature to zero degrees with the help of catalysts and stiffeners. For this reason, this group of adhesives is widely used in industry. After adding the hardener to the epoxy, the chemical meshing process begins generating heat until it is completely hardened. This range of adhesives is highly adaptable to environmental conditions and can be formulated for any application.

Manufacture of epoxy adhesives

Two-part epoxy systems consist of a resin fraction and a hardening fraction that exhibit different thermal, optical, electrical and mechanical properties in different formulations. These systems can also be formulated to be hardened at room temperature and at high temperatures.In Part A (Epoxy Resin Section) various types of epoxy resins, epoxy novalac, epoxy resins of very low molecular size and weight, plasticizers, aliphatic and aliphatic epoxy resins, thixotropic agents, degreasers, mineral and organic additives. Part B (epoxy hardening section) also consists of a variety of amino hardeners – aliphatic, cyclo-aliphatic, aromatic, anhydride, mercaptan, manish bases, polyamides, amidoamine, and inorganic and organic additives.

Properties and advantages of two-part epoxy adhesives

Two-part epoxy adhesives, as a versatile structural adhesive, have the highest consumption in various industries due to their ability to bond different types of surfaces to each other, very high strength, chemical and environmental resistance.

These adhesives have the ability to permanently bond with a very high strength at various levels in the industry

  • Resistant to vibration and shocks
  •  Electrical insulation
  • Resistant to temperature cycles
  •  Peripheral curing
  • The ability to fill in the cracks
  • The ability to permanently connect heterogeneous surfaces
  • uniform pressure distribution
  • Lasts for at least 50 years
  • Ease of use and installation
  • Completely solid and solvent free
  •  Chemical resistance in alkaline and acidic environments
  • Resistant to corrosion in adverse weather conditions
  • Protective cover against moisture and sunlight

Megatite is a manufacturer of two-component epoxy adhesives for various applications in the fields of construction, petrochemical, oil and gas, power, water and wastewater.

Applications of two-component epoxy adhesives in various industries

These adhesives are used in most industries due to their high mechanical and chemical properties:

In the civil engineering and construction industries

To bind all kinds of building materials together for life and permanently, they are used to repair and strengthen all kinds of bridges, structures, concrete, steel, mortar and polymer anti-corrosion fillers.

In the electrical and electronics industry

Since epoxy adhesives are electrically insulating, they are used in the production of various electrical components and structures (transformers, etc.)

In the aviation and aerospace industry

Due to the very low strength-to-weight ratio, epoxy and epoxy adhesives are used in aircraft and vehicle parts.

In the oil, gas, petrochemical and marine industries

Due to the very high resistance to abrasion, epoxy adhesives are used to repair and rebuild, bond parts to each other for life and repair the leakage.

Two-component epoxy adhesives selection agents

One of the most important factors to consider when choosing an epoxy adhesive is the work life of the epoxy adhesive. It is important to know when the epoxy adhesive has dried and hardened, or when internal chemical reactions are complete and the adhesive has reached its final strength. There are two concepts in terms of time of use. One is the time it takes for the adhesive to change from a liquid to a solid state, and the other is the time it takes for the adhesive to reach its final strength in most chemical chains.

The application temperature of the adhesive, the environmental chemical conditions, the amount of temperature and mechanical shocks to the adhesive are other important information that must be chosen carefully in the appropriate adhesive.

Another factor to consider when choosing a suitable epoxy adhesive is the surface material. Even if two-part epoxy adhesives are generally suitable for all surfaces from metal to plastic, glass and wood, special epoxy adhesives have been developed for each.Some samples of epoxy binders are currently being produced, such as electrode epoxy. Epoxy adhesive designed for electrical molds. The important thing about electrical molds is that the electrode epoxy is highly resistant to shock and vibration and resists moisture to prevent corrosion. Epoxies are very good insulators of the flow of electricity, so they are used in the production of printed circuits, circuit surface insulation, hybrid chips and transistors.Adherence to proportions, complete cleaning of the surface from grease, dust and any contamination and removal of hidden moisture are important factors so that when using epoxy, the epoxy never separates from the surface.Color is also an important factor to consider when deciding on an epoxy adhesive. The epoxy adhesive must be aesthetically pleasing to the surface coating. Fortunately, two-part epoxy adhesives are available in a wide variety of colors, even for those difficult to match, and they are also available in transparent form.

conclusion

Epoxy resin contains a wide range of mesh-related products. Epoxy can be formulated for different uses. Today, due to the cost-effective properties of this material compared to other materials, its consumption has become widespread and will increase over time.In this article, Megatite Group tried to inform you scientifically and professionally about the molecular structure of epoxy, types of epoxy resin, properties and advantages of epoxy resin adhesive, as well as its application in various industries.Have you ever used epoxy resin? Can you add other applications and features? Or do you have another question on your mind? Write us down below. We look forward to reading your comments and answering your questions.

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