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How to Bond Materials

At first glance, bonding two surfaces may seem straightforward. However, the choice of adhesive is critical, as it must be formulated to work with the substrates and meet performance requirements. Failure to select the appropriate adhesive can result in an unreliable connection, potentially leading to structural failure. Let’s discuss what adhesive bonding is, how cyanoacrylate adhesives work, and how materials can be bonded with them.

What is Adhesive Bonding?

Adhesive bonding involves joining two surfaces together to form a seamless bond. The bond is achieved by applying glue, epoxy, or other plastic adhesives to one or both surfaces. In some cases, a piece of adhesive tape with a two-sided coating can be placed between surfaces to bond them. The bond forms by solvent evaporation, by a curing process with applied heat or pressure, or simply by curing over a period of time.

Glues and adhesives form bonds of varying strengths. New and advanced self-curing glues have been developed that can create bonds as strong as, or stronger than, the materials they join. High-strength glues and adhesives are a common choice in many manufacturing, industrial, and household uses as a result.

Depending on the formulation, some adhesives and glues must be remixed prior to application to distribute ingredients. Others, such as two-part epoxies, must not be mixed until they are ready to be used. Some glues must be cured by applying heat or UV radiation, while others cure in the open air over a period of time. Our focus here will be cyanoacrylate glues, which do not require mixing, set quickly, and cure by atmospheric moisture (humidity) and latent moisture on the bonding substrate surface.    This is called an anionic bond or anionic polymerization causing the cyanoacrylate monomer to transition to a polymer bonding materials together.

How Do Cyanoacrylate Adhesives Work?

Cyanoacrylate, often referred to as an instant adhesive, CA glue, or super glue, is a liquid acryl monomer that achieves a fixture time in seconds. Over a period of hours, the glue cures completely for a high-strength, permanent bond.

When placed between two surfaces, cyanoacrylate reacts instantly, forming polymer chain bonds as soon as it is exposed to residual moisture on the substrate surfaces. As a single-part adhesive, it does not require mixing and there is no need for heat or UV light to cure it.

In some applications in which the adhesive is exposed instead of being sandwiched between two surfaces, curing can be delayed. In these cases, a liquid activator may be sprayed on the glue to help it harden. These activators are also used in applications where one or both of the surfaces to be bonded is very dry, acidic, or porous.

Bonding Materials with Cyanoacrylate

Many materials can be bonded successfully with cyanoacrylate adhesive including ceramic, rubber, elastomers, textiles, metal, wood, and plastic. All-purpose, standard formula cyanoacrylates work well in many situations; however, they can also be formulated to enhance characteristics for specialized applications. Examples include:

• Impact resistance
• Thermal resistance
• Peel resistance
• Rigid or flexible curing
• Water resistance
• Low odor
• Low bloom
• Specific substrates (e.g., soft/flexible, metal, plated material, porous material)
• Ultra-fast set time
• Extra clear when cured
• Thixotropic, no-run formula

Some materials are more challenging to bond. These may include very dry or acidic substrates; polyolefin, acetal, and fluoropolymers; or low surface energy plastics such as polypropylene and polyethylene. Surface treatment primers and adhesive accelerators are available to prepare them and improve adhesive performance.

Use Aron Alpha Adhesives for Your Application

Adhesive bonding is a common, efficient, and effective process in manufacturing, medical applications, and household settings. Aron Alpha is a leader in cyanoacrylate innovations, helping to improve productivity and product quality for its customers.

We offer a range of instant adhesive formulas, primers, and accelerators, as well as custom formulations to meet your specific requirements. Lab testing, on-site consultation, and prototype testing services are also available.

Contact us to learn more about our line of adhesives or request a quote.

Curing Speed of Cyanoacrylate

Cyanoacrylate adhesive, also called “super glue,” is a strong, fast-drying glue used in industrial, commercial, and household settings. This versatile adhesive is easy to work with, but due to its short open time and permanent adhesion, it’s important to understand how it works, its cure time, and how to prepare bonding surfaces for the best results. Read on to learn more!

What is Cyanoacrylate?

Cyanoacrylate adhesive is a liquid acryl monomer that cures or hardens in the presence of moisture. There is no mixing required, and residual moisture is usually sufficient to initiate curing, though some applications require small amounts of water or liquid activator. As it dries, polymer chains form and create a strong bond without supplemental UV radiation or heat for full curing.

There are several types of cyanoacrylate, including modified cyanoacrylates designed for less-reactive conditions, modified curing and fixture times, and longer shelf life. It is used in many household, medical, and industrial settings on materials including:

• Wood
• Metal
• Plastic
• Rubber
• Elastomers
• Paper
• Leather
• Fabric
• Ceramics

It’s important to exercise caution when applying cyanoacrylate to new materials. Some applications result in high exothermic (heat-releasing) reactions, especially when used in large amounts. For the same reason, cotton or wool gloves are not recommended when handling cyanoacrylate. Disposable nitrile gloves are best for protection against cyanoacrylates getting on worker’s hands.

Curing Speed of Cyanoacrylate

How long does cyanoacrylate take to cure? While most adhesives cure after a heating or evaporation process, cyanoacrylate fixes rapidly on contact with moisture. Even a small amount of humidity starts the curing process.

This contributes to cyanoacrylate’s incredibly short fixture time. Total cyanoacrylate cure time depends on several factors:

• Surface/material type
• The amount of moisture/humidity present
• Type of cyanoacrylate

There are even faster forms of cyanoacrylate than store-bought superglues, such as surface-insensitive varieties. Toughened types and hybrid cyanoacrylate/epoxies have slower cure times.  

Fixture Time vs. Cure Time

How does cyanoacrylate cure so quickly? Technically, it is the fixture time that is very fast, often between 5 and 90 seconds. This is the amount of time until the glued assembly can be carefully handled. Full curing time, however, is when the bonding process is permanent and complete. Cyanoacrylate cure time is anywhere from 8 to 24 hours depending on the materials being bonded and the adhesive formulation used.

The Super Glue brand once demonstrated cyanoacrylate’s immense tensile strength by lifting a car shortly after application. Even more impressive, though, is the fact that this was only its fixture strength and the full cyanoacrylate cure time results in even stronger bonds.
Super glues are known for their high tensile strength, even at fixture time. Some famous examples have been illustrated in advertisements over the years, including vehicles and even people.

Preparing Surfaces for Application Cyanoacrylate Adhesives

How can bonding strength be maximized? Clean surfaces always bond best. Best practices include removing dust, oil, or grease with a detergent or cleaning solvent. Bonding primers (i.e., adhesion promoters), can also improve cyanoacrylate bonds by modifying surface energy. This promotes greater chemical reactivity between the adhesive and the surface, while also protecting the surface from contamination.

Industrial Adhesive Solutions Adapted to Your Exact Applications

At Aron Alpha, we manufacture and supply industrial cyanoacrylate adhesives, accelerators, and primers for use in many industries including:

• Automotive
• Electronics
• Industrial Assembly
• Medical
• Woodworking
• Construction
• Maintenance, Repair, and Operations (MRO)

We also offer custom formulations, lab services and testing, industrial adhesive consultation, and prototype testing.

To discuss cyanoacrylate formulations and cure time for your applications, contact us or request a quote to learn more.