Application of Epoxy in Various IndustriesHow epoxy is used in different industries
Epoxy is widely used and has become a versatile product in many industries for its high adhesion quality. Due to its resistance to heat and chemicals, epoxy adhesive is an ideal product for anyone who needs a strong adhesion in their work. On the other hand, epoxy resin is water resistant and being in wet or damp conditions does not affect its durability. Therefore, it can be an alternative to many common materials with many problems. In this article, you will be introduced to the chemical formulas of epoxy resin and their use in various industries.
Why is epoxy better than other materials?
Epoxies have very unique physical, chemical and mechanical properties, so it has found wide applications in the construction industry, especially reinforcement in various parts of concrete structures. Compared to other traditional thermostatic or thermoplastic resins, epoxy resins have certain advantages, including:
- Long lasting
- Shock resistant
- Excellent chemical resistance
- Suitable electrical properties
- Low shrinkage during processing
- Excellent moisture resistance
- No volatile organic compounds (VOCs)
The importance of chemistry in epoxy
Epoxies are thermoset polymeric resins in which the resin molecule contains one or more epoxide groups. Chemistry can adjust the molecular weight or viscosity as needed in the end use. There are two main types of epoxy: glycidyl epoxy and non-glycidyl epoxy. Epoxy glycidyl resins can be referred to as glycidylamine, glycidyl ester or glycidyl ether. Epoxy resins are non-glycidyl or aliphatic or cycloaliphatic resins. One of the most common epoxy glycidyl resins is formed using bisphenol A (BPA) and combined with epichlorohydrin in reaction.
Epoxy resins are cured by the addition of a curing agent, commonly called a hardener, and are the most common type of amine-based curing agent. Unlike polyester or vinyl ester resins, the resin is catalyzed with a small addition of catalyst. Epoxy resins usually require the addition of a much higher curing agent to the hardener, often in the form of 1-1, 2-1, 4: 1, or 5: 1. Epoxy resin can be hardened by adding heat-resistant polymers.
Pre-impregnated epoxy is a tacky uncured resin. At this stage, layers of pre-impregnated epoxy are allowed to be cut, stacked in the mold, and then stabilized and processed by adding heat and pressure. Pre-impregnated epoxy in stage B must be kept at a low temperature to prevent premature curing, so companies that use pre-impregnated epoxy must keep them in refrigeration units or freezers to keep them cool.
Functional purposes of fiber-reinforced epoxy
Epoxy is used as a resin matrix to effectively hold the fibers in place in the field of fiber-reinforced polymers. The matrix must distribute the forces between the strands of fibers and protect them from any damage. Thermostatic resins, which are actually a group of plastics that will no longer melt after production and once melted and formed, are widely used in this field. Vinyl ester and epoxy are two common types of matrices. Epoxy has more advantages and costs compared to vinyl ester. Epoxy is compatible with all common reinforcing fibers on the market, including glass fiber, carbon fiber, aramid and basalt.
Here are some common uses for epoxy resin:
- Industrial coatings
- Versatile adhesives
- Non-slip covers
- Fiber-reinforced plastics
- Creates adhesion in cement and mortar
Fiber-reinforced epoxy joint products
Epoxy resin may not be used for each of these. For example, dense molded epoxy resins are heat-activated, while an injectable resin may have a lower environmental curing and viscosity. Products that are usually produced with epoxy are included in this list:
- Secondary winding
- Pressure Vessels
- Recreational equipment
- Insulation rods
- Types of profiles
- Aircraft parts
- Skiing and snowboarding
- Circuit boards
Autoclave and pre-impregnated
- Space equipment components
- Bicycle frames
- Hockey stick
- Wind turbine blades
Application of epoxy resin as an adhesive
One of the most common applications of epoxy resin is for adhesives. Due to its adhesion properties, epoxy allows it to be used in construction and engineering, petrochemicals, oil, gas, water, sewage, etc. But epoxy adhesives are not limited to construction and industrial applications, they can be used in any application. Epoxy resin is also commonly used in the construction of vehicles, snowboards, airplanes and bicycles. In general, epoxy has various applications due to its various properties such as flexibility, hardness, opacity or transparency.
Epoxy adhesives make up a large part of the group of adhesives called structural adhesives or engineering adhesives, which include polyurethane, acrylic, cyanoacrylate (cyanoacrylate) and other chemicals, which are very effective. Used in aircraft, automobiles, bicycles, boats, golf clubs, skis, snowboards, and other applications that require high strength, epoxy adhesives can be used for almost any task.
They can be used as adhesives for wood, metal, glass, stone and some plastics. They can be flexible or rigid, transparent or opaque and colored. They can also do the adhering process fast or slowly. Epoxy adhesives are more resistant to heat and chemicals than other conventional adhesives.
– In general, heat-cured epoxy adhesives are more resistant to heat and chemicals than epoxy adhesives that are cured at room temperature.
– The strength of epoxy adhesives decreases at temperatures above 350°F or 177°C. Some epoxies are cured by exposure to ultraviolet light. Such epoxies are commonly used in glass, optical fiber and optoelectronics. In the past, solvent-based and solvent-free epoxies were used. But according to the latest technologies, waterborne epoxy is used today. This protects the metal parts from corrosion.
Megatite is a manufacturer of two-part epoxy adhesives for various applications in construction, petrochemical, oil, gas, power, water and wastewater industries.
Durability of repairs and reconstruction with epoxy
Due to their high adhesion properties, many consumers use epoxy resin to repair and maintain their materials, equipment, and appliances. Concrete cracks, broken stones, or fragile items such as tiles, ceramics, glass and porcelain can be quickly fixed with epoxy resin. Wood, metal, rubber or other similar materials can also be repaired well with epoxy. Using epoxy resin on the fragile part, a narrow and strong barrier is formed that this connection will remain for years.
For repairs and reconstruction with epoxy, pay attention to two points, the desired surface must be free of any dust, oil, grease and decomposing materials, and the surface must be completely dry for the epoxy to achieve acceptable adhesion.
Epoxy revolution in coatings and sealants
Another feature of epoxy is its anti-corrosion property. Epoxy is an ideal solution for many industrial appliances or home appliances that may normally rust over time.
Another application of epoxy resin is decorative flooring. Epoxy flooring is an environmentally friendly flooring and is a good alternative to traditional flooring due to its reduced need for pesticides and water consumption. Epoxy flooring consists of three general layers, the first layer for concrete, the middle layer and the final layer or surface. Epoxy flooring can be used in pharmaceutical, oil, gas and petrochemical industries, water and wastewater industries, detergents industry, warehousing, rail transportation industries, chemical factories, dyeing industries, hospitals and health centers.
Use of epoxy resin in the paint industry
Epoxy paints, known as powder coatings, are found in many household goods such as dryers, detergents, stoves, and similar white goods. This type of paint is usually used more in commercial fields. Epoxy paint is an excellent choice for applications due to its water purity, high hardness and protective coating. Cast iron, aluminum and steel are other metals that can be better colored with epoxy.
Applications of epoxy as paint and coating
Epoxy coatings are often used in industry, especially in the automotive industry. Because they are more heat resistant than latex and alkyd based paints. Epoxy paints can be damaged by exposure to ultraviolet rays, which is called plaster.
Epoxies are used as a powder coating for washers, dryers and other white goods. Epoxy powder coatings (FBE) are widely used to protect against corrosion of steel pipes and fittings used in the oil and gas industry, drinking water transmission lines (steel) and concrete reinforcement bars, as well as primers to improve paint adhesion. Car paints and marine paints are used especially on metal surfaces that must have high resistance to corrosion and rust.
To prevent rusting of metal cans and containers, especially for acidic foods such as tomatoes, metal containers are often coated with epoxy. Epoxy resins have several uses, including those used as flooring. They are resistant to mechanical abrasion, chemical reactions and heat stress and are used in places such as industrial facilities, car parks and shopping malls. They can also have decorative applications. Terrazzo flooring, chip or corrugated wood flooring and colored granular flooring are some of the decorative flooring.
How to process epoxy
Epoxies are processed in various ways. They react with fatty acids from oils to produce epoxy esters that are treated like alkyds. Among them are L8 (80% Barzak oil) and D4 (40% dehydrated oil). These materials, as primers, usually react with styrene to make epoxy esters.
To make very resistant layers, phenolic treatment is used to make the coating, treatment of esters with amino resins and pre-treated epoxies with amino resins. Solvent-free epoxies as ship liners during construction can be one of the best examples. This product is used by using hot airless air spray system by mixing in the upper part of the device, and solves the problem of retaining the solvent under the membrane, which later causes problems such as adhesion.
Application of epoxy in industrial tools and equipment
Epoxy is used in industrial tools to produce molds, original models, laminates, castings, equipment and other industrial tools. This product can replace metal, wood and other traditional tools and generally increase efficiency, reduce overall cost and shorten construction time in many industrial processes. Epoxies are also used in the production of fiber or composite reinforced parts. They are more expensive than polyester resins and vinyl ester resins. But thermoset polymer matrix composites are usually stronger and more temperature resistant.
Effective epoxy in wind turbine
Epoxy resins are used as bonding matrices only with carbon or glass textured fabrics to produce very high strength composites. By specifying the weight, it is possible to produce longer and more efficient rotating water turbine blades with epoxy. In addition, epoxy resins are used for sea and coastal wind power installations as protective coatings on metal towers, columns and concrete foundations. Aliphatic polyurethane coatings are used to ensure complete protection against UV rays, prolong operation and reduce maintenance costs.
Electric generators that are connected to the rotor blades via a drive convert mechanical wind energy into usable electrical energy. This equipment relies on epoxy electrical insulation and high heat resistance. The same is true of transformers, liners, spacers and composite cables that connect windmills to a grid in Europe.
Epoxy in recreational equipment
The main criteria of sports equipment manufacturers are high strength and weight loss in accessories. Ski, snowboard, surfboards are made of fiber reinforced epoxy. Epoxy resin plays a key role in the construction of yachts and commercial and military ships in combination with multi-axis and one-way fabric.
Epoxy in the shipping industry
Epoxy is used in the marine sector for two reasons: it has better mechanical properties than conventional polyester resins, is used for the commercial manufacture of parts in which strength and weight are important. Another reason for its high strength is its gap-filling properties and excellent adhesion to other materials, including wood, which has boosted aircraft and boat construction projects. Ordinary gel coatings combined with polyester resins and vinyl resins do not adhere to epoxy surfaces. Epoxy, on the other hand, adheres very well to polyester resin surfaces. Flow coatings, which are commonly used for the lining of polyester fiberglass boats, are also compatible with epoxies.
Build a boat with composite
Epoxies are sold in hardware stores. It usually contains a separate hardener and resin that must be mixed immediately before use. They are also found as repair resins for marine use in shops where boats are sold. Epoxies are not used on the outer layer of a boat. Because they are destroyed by exposure to UV light. They are often used when repairing and assembling boats and then coated with common or two-component polyurethane paints or UV-curing oils that are UV resistant.
The difference between epoxy and polyester
Epoxy materials tend to harden gradually. While polyester materials tend to harden quickly, especially if more catalysts are used. Chemical reactions are exothermic in both cases. Large amounts in the mixture cause more heat and accelerate the reaction.Polyester resins are usually of low strength. Unless a reinforcing material such as glass fiber is used. In this case, too, they are relatively fragile unless reinforced, have little adhesion, and are very inexpensive. In contrast, epoxies are inherently strong and somewhat flexible and have excellent adhesion.
Epoxy resins require a precise combination of two components to form a third chemical. Depending on the required characteristics, this ratio may be 1: 1 or more than 10: 1. But in any case they must be mixed thoroughly. The final product is a plastic that is very resistant to heat. They are relatively ineffective until they are thoroughly mixed. However, hardeners tend to be more chemically active, in which case they must be kept away from air and moisture. The reaction rate can be changed by controlling the temperature or by using different hardeners, which can also change the nature of the final product.
In contrast, polyester resins are usually available in upgraded form. They are already mixed and change from liquid to solid, albeit very slowly. The only variable in this process is the use of a highly toxic reactant called methyl ethyl ketone peroxide (MEKP). The presence of a catalyst reduces the desired properties in the final product. Thus, small amounts of catalyst should be used to continue hardening at an acceptable rate. Therefore, the curing rate of polyesters can be controlled in terms of the amount and type of catalyst as well as the temperature.
Three methods of epoxy bonding
As an adhesive, epoxies bond in three ways:
A) Mechanical: The bond surfaces must be rough.
B) Proximity: Physically processed resins are so close to the bond surfaces that they are difficult to separate.
C) Ionic: Epoxy resins form ionic bonds at the atomic surface with surfaces.
The third option has the strongest link between the options. But polyester resins only form the bond using the first two, which greatly reduces the efficiency of the adhesive and marine repair.
Epoxy in the aerospace industry
In the aerospace industry, epoxy is reinforced with fibers and used as a structural matrix material and structural adhesive. Conventional fiber reinforcers include glass, carbon, and Kevlar.
Materials such as wood and other old materials also adhere to each other with epoxy resin. Epoxies are usually more resistant than other types of resins in terms of mechanical properties and environmental degradation. Early designers of small aircraft and drones used epoxy-based composites. Stuttgart epoxy composite structures (Akaflieg fs29) play an important role in the military aviation industry today to reduce aircraft weight.
In conclusion, modern aircraft have shown better fuel economy and less CO2 emissions. More than 50% of jets such as the Boeing 787 and Airbus A 350 are made of composite, with epoxy playing a major role. Processing technology in Airbus 350 A and Boeing 787 parts (Prereg) and resin transfer molding (RTM) are especially effective in the urban aviation and military aviation industries. Resin processing and injection technologies are also used in the construction of small aircraft and drones.
Composites in the automotive industry
Major automobile and truck manufacturers are considering glass and carbon fiber composites for mass production. This product is used in the structural parts of the car body such as fenders, trunk and hood.
The use of composite blade springs increases the cargo capacity, especially in light trucks. Replacing composite blade springs with steel reduces weight by 50%. The new generation of vehicles, especially electric vehicles, need chassis and other significant structures made of reinforced polymer carbon fiber (CFRP)
Epoxy resin in electronic systems
Epoxy resin plays an important role in the electronics industry. Epoxy resin is used in the production of insulation, motors, transformers and generators. Because epoxy resins are excellent insulators and protect against dust and moisture in short circuits, they are one of the main resins used to create the circuit.
The position of epoxy in the electronics industry
In the electronics industry, epoxy resins used in integrated molding circuits, transistors, hybrid circuits and printed circuit boards are the main resins. The largest volume of the circuit board type is an FR-4 board, which consists of layers of glass cloth and is bonded to a composite by an epoxy resin. Epoxy resins are also used to bond copper foil to circuit board substrates. Since these applications require automatic extinguishing properties, flame retardant epoxy resins or epoxy formulations with flame retardant additives are used.
Insulation epoxy suitable for medium and high voltages
Electric casting materials are formulated polymeric materials used in the production, transmission and distribution of electrical power, devices, electronic and electrical components. In such formulations, epoxy resin from the electrical and electronics industry is reduced in voltage from 400 kV to 1 V. The purpose of these products is to insulate, protect or cover the environment or devices in the environment from electric current.
Bisphenol-based epoxy resins using dicarboxylic anhydrides or amines are used for internal use Cycloaliphatic epoxy resins, preferably 1,2 cyclohexic acid 2,3 Epoxypropyl epoxy, in combination with cycloaliphatic dicarboxylic anhydrides and silanised silica flour, are the basis for the production of durable electrical insulation, for example, Liners, and transformers.
Epoxy in the oil and petrochemical industry
Epoxies can be used to bond selected layers in a reservoir that produces too much salt water. This method is called silent water purification operation.
Artwork with epoxy
When epoxy resin is mixed with pigment, it can be used as a painting tool. Layer it on top of each other to form a complete image. They also use epoxy resin in jewelry, decorations, stickers and art decoupage works on counters and tables
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