Epoxy adhesives are among the most popular and versatile bonding solutions available today. They are ideal for a range of industries and applications, including electronics and electrical components, aerospace, construction, EV components and batteries (including lithium), marine, repair, and adhesives for structural and other purposes. They are known for their strong bonding properties, durability, and resistance to water, chemicals and many harsh environments. They are highly versatile in light of the fact that a wide range of processing, cure and property characteristics can be achieved. Systems may be filled or unfilled, or thixotropic. Almost any property can be modified.

With over 50 years of experience developing and manufacturing epoxy resin systems, United Resin has built a reputation for excellence in the industry and strong technical knowledge of the chemistry of epoxy systems. Our expert team works continually to create high-quality products with exceptional performance, reliability, and durability.

The Composition of Epoxy Adhesives

Epoxy adhesives are, in general, two-part bonding solutions. The two components, resin and a hardener, are mixed in a specific ratio to create a strong adhesive that cures over time. When epoxy resin is mixed with a hardener, a chemical reaction is initiated that transforms the combined liquid ingredients into a solid.  During the curing process, epoxy moves from a liquid state, to a gel-like state, to a solid state. The cure time is impacted by temperature, mass of material that is being cured, and the structure of the container in which it is cured. Epoxy systems can be formulated to fine tune desired working time.

The following are the two main components of epoxy systems:


This is the main ingredient in the resin component of the epoxy system. It is a viscous liquid that is often clear or amber in color. The resin is responsible for providing the adhesive with its bonding properties and resistance to chemicals, water, heat, and other environmental challenges. The resin serves as a thermosetting polymer that initiates polymerization (also called curing) when mixed with a hardener (sometimes referred to as a catalyst).  During polymerization, epoxy resins form cross-links, creating a three-dimensional polymer of great mechanical strength.


This is the catalyst that causes the resin to cure and harden. It is often a clear liquid, and the resin and hardener are mixed in a range of ratios specific to the application or product. The two mixed components create the adhesive.

Epoxy Resin

There are a number of resins used in epoxy resin systems. The predominant resin component of epoxy adhesive systems is Bisphenol resin or Novolac resin.

Bisphenol Epoxy Resins

Bisphenol-A diglycidyl ether (DGEBA) is created by the reaction of bisphenol-A with epichlorohydrin in the presence of a basic catalyst. As a result, it has the lowest molecular weight of all epoxy resins.

Novolac Epoxy Resins

This type is created by the reaction of phenol or cresol, formaldehyde (methanal), and epichlorohydrin producing EPN or ECN varieties without solvents or VOCs. It offers high adhesive strength, coverage, protection, and durability.

Advantages of Epoxy System Adhesives

There are many benefits in using epoxy adhesives, including:

High Strength and Durability

Epoxy adhesives are known for their high strength and durability, by their ability to withstand high stresses and heavy loads. Epoxy resin creates a strong bond between a variety of materials (substrates), including metal, glass, wood, ceramics, and many plastics. Epoxy adhesives include a class of adhesives called “structural adhesives,” which are high performance adhesives used in the construction of aircraft and automobiles and other applications where reliable, high strength bonds are required that can handle substantial loads.

Chemical Resistance

These adhesives are highly resistant to chemicals, such as acids, bases, and solvents. This makes them excellent options for use in industrial settings and in other environments where exposure to chemicals is common.  The chemical resistance can extend the life cycle of many applications.

Temperature Resistance

Epoxy system adhesives can withstand a wide range of temperatures, from extremely low to extremely high. This makes them ideal for use in the aerospace, automotive, and electronics industries.


Epoxy adhesives are highly versatile in light of the fact that a wide range of processing, cure and property characteristics can be achieved. Almost any property can be modified. They are suitable for multiple applications, such as bonding, sealing, and coating. Additionally, these adhesives can be formulated to have various properties, including flexibility, toughness, and hardness. This makes them suitable for multiple applications and may reduce the need for multiple materials. Epoxy is compatible with various materials, including metal, wood, concrete and plastic.

Easy Application

Epoxy system adhesives are easy to mix and apply, with packaging for manual and semi-automated application. They can be poured or applied using a brush, roller, spray gun, cartridge gun, syringe or bottle. They also can have a long working time, allowing users to adjust the bond cure time as needed. United Resin has epoxy systems that are two-component, as well as one-component systems for easier use.


Compared to other adhesive types, epoxy adhesives are cost-effective, by providing a high level of strength and durability. They also have a long shelf life, making them ideal for large-scale projects, and can be applied with minimal waste. Epoxy resin can reduce the need for metal fasteners and improve the aesthetics of many applications.

Moisture Resistance

Epoxy system adhesives are highly resistant to moisture, making them ideal for damp and wet environments, such as for marine and outdoor applications.

Electrical Insulation Properties

These adhesives have excellent electrical insulation properties and thermal conductivity, making them suitable for the electronics industry. They can be used to bond or encapsulate electrical components and to create insulating layers, thus improving energy efficiency.


It is important to follow all instructions for mixing, application and curing.  They should be used with appropriate precautions and with proper handling following recommended safety measures.

All United Resin materials are non-hazardous, REACH/RoHS compliant and contain no solvents.

Applications of Epoxy System Adhesives

Epoxy resin has numerous applications across various industries. The chemistry of epoxies allows a large range of properties and epoxy adhesives can be developed that meet almost any application. Some of the most common applications include the following:

Electronics and Electrical Components

In electronics, epoxy resin is popular for potting and encapsulating sensitive components, such as circuit boards, fiber optics, LED components and microchips. By sealing the electronics in an epoxy resin coating or encapsulant, the material protects against moisture, dust, and other contaminants that could cause damage or interference, and may afford protection of proprietary trade secrets. Another benefit of an epoxy resin system is fire retardancy, with a number of formulations being rated UL (UL Solutions) 94 VO.


Epoxy resin is widely used in the manufacturing of aircraft components, such as wings, fuselage, and control surfaces. Its high performance and reliability help ensure safety and longevity in the harsh and demanding conditions of aerospace environments.


In the construction industry, epoxy resin is a versatile material for bonding concrete and reinforcing steel bars and for repairs. It is an excellent bonding solution for many construction needs due to its strength, durability and resistance to chemicals and abrasion.

EV Components and Batteries

Epoxy resin is critical in manufacturing electric vehicle components and lithium-ion batteries. As a binder, it helps hold the electrode material together. Meanwhile, as a coating or encapsulation material, it protects the electrodes from degradation caused by moisture and other contaminants.


Epoxy resin is commonly used as a coating material for boats and ships to protect them from corrosion and damage caused by water exposure, and in many marine repair applications.


These adhesives, including epoxy putty sticks, are ideal materials for repairing and restoring wood, concrete, and metal. They can repair cracks, holes, and other types of structural damage.

Tips for Preparing Surfaces for Epoxy Resin

To ensure optimal adhesion with epoxy resin, it is essential to prepare the surface correctly. Surfaces must be clean, dry and sanded. For good adhesion, bonding surfaces must be clean of any contaminants. All bonding surfaces must be dry. Preferably bonding surfaces should be sanded, and all sanding dust or grit must be removed. A properly prepared surface will allow good adhesion. Here are some tips to help you perform this process correctly:

    • Clean the surface with a degreaser to remove oils and contaminants.
    • Allow the surface to dry completely before applying epoxy resin.
    • Sand difficult surfaces lightly with a fine-grit sandpaper.
    • Remove wax, grease or any residue grit before using epoxy resin.
    • Avoid masking tape on epoxy resin surfaces to prevent adhesion issues.

Innovative Epoxy Adhesive Systems From United Resin

At United Resin, we offer innovative epoxy system adhesives to meet our customers’ unique needs. In addition, our commitment to ongoing product development and quality assurance ensures that our adhesives offer exceptional performance. With global shipping experience, we can serve customers anywhere in the world.

Trust United Resin for your epoxy adhesive needs and experience the difference that quality, innovation, customer service, and commitment can make. Contact us now to learn more about our epoxy adhesive systems and other services we can provide to benefit your business. Our trained professionals can assist you with every step of the process! We can guide you from initial product selection to testing and production line manufacturing.

The information presented in this blog is intended for general background and informational purposes only and is not intended as advice pertaining to any product, application or process.  We encourage you to contact us for information concerning your specific needs and requirements and to discover how United Resin may assist you.