UV Adhesive, also known as UV light-curing adhesive, has been widely used for decades, especially in manufacturing industries such as medical device assembly and electronics. In recent years, UV adhesives have experienced a surge in applications within electronics and many other industries. However, certain challenges arise when applied to surfaces like plastics – materials that absorb UV light exceptionally well. This is because UV light struggles to penetrate plastic surfaces, reducing the adhesive’s ability to cure effectively. To address this, UV Dual Cure adhesive with secondary curing mechanisms was developed, enabling the curing process without the need for UV light exposure. So, what are the secondary curing mechanisms of UV Dual Cure adhesives? Let’s explore in this article!
What is UV Dual Cure Adhesive?
UV Dual Cure adhesive is a type of adhesive that can cure or harden through two distinct mechanisms: UV light exposure and a secondary curing process (typically chemical). This makes it an ideal solution for applications requiring strong bonding, even in areas not directly exposed to UV light.
Read more: UV Adhesive – A Comprehensive Overview
Why a secondary curing mechanism is necessary?
In the application of traditional UV adhesives, UV light plays a crucial role in initiating and curing the adhesive. However, in many cases, the material’s surface may be inconsistent, or UV light may not penetrate sufficiently to activate the adhesive. As mentioned earlier, many plastics effectively absorb UV light to protect their surfaces from becoming brittle, cracked, or discolored. However, this very property makes it difficult for UV light to penetrate, reducing the adhesive’s activation beneath the surface and leading to uneven bonding.
Moreover, in complex designs or products with dense structures, not all areas are directly exposed to UV light. Shaded or recessed regions often lack sufficient UV energy to cure the adhesive, compromising the bond’s strength and performance.
A secondary curing mechanism overcomes these challenges, ensuring consistent bonding even in areas where UV light cannot reach.
The secondary curing mechanism helps:
- Enhance bonding strength in shaded or recessed areas.
- Ensure consistent performance across the entire bond, regardless of UV exposure.
- Provide flexible application on various materials and in different environments.
Secondary Curing Mechanisms of UV Dual Cure Adhesive
While traditional UV adhesives are primarily known for their UV light-curing mechanism, the evolving demands of modern applications have driven the development of UV adhesives with integrated secondary curing mechanisms, forming UV Dual Cure adhesives. Below are three common curing mechanisms for this type of adhesive:
UV Dual Cure Adhesive with Anaerobic secondary curing mechanism
UV Dual Cure adhesives with an anaerobic secondary curing mechanism operate in two distinct phases. The first phase involves rapid curing when the adhesive is exposed to UV light, initiated by photoinitiators. However, in areas shielded by opaque components or shadowed regions, the adhesive can cure anaerobically (in the absence of air). This mechanism ensures robust, durable bonds that resist chemicals and environmental factors. Such adhesives are frequently used in applications involving metallic surfaces, such as in electric motor assembly—securing bearings or connecting shafts and hubs in rotors and stators. Additionally, they are suitable for bonding glass or ceramic-coated glass in various industrial applications.
| PERMABOND UV7141 is a UV-curable adhesive with a secondary anaerobic cure mechanism. This makes it ideal for bonding materials such as ceramic-coated glass, mirrors etc. where UV-light cannot penetrate to provide full cure in shadow areas. This dual cure mechanism helps speed up production rates. The UV cure tacks the components in place in seconds, reducing the need for jigging. The bulk of the adhesive then cures more slowly to produce optimum performance. |
UV Dual Cure Adhesive with thermal secondary curing mechanism
This type of adhesive is an ideal solution for applications requiring fast and precise processes while ensuring high adhesive strength. Initially, the adhesive cures rapidly upon exposure to UV light, enabling immediate handling of parts without waiting for the adhesive to fully harden. The curing process is then completed when the adhesive is exposed to heat, enhancing the mechanical strength and stability of the material on printed circuit boards (PCBs) or surfaces requiring high precision.
This adhesive is particularly favored in applications related to Advanced Driver Assistance Systems (ADAS), such as LiDAR and RADAR sensors, as well as active alignment processes for cameras. Formulated with modified epoxy, it maintains shrinkage below one percent throughout the curing process. Additionally, it exhibits extremely low thermal expansion, even under changing temperature and humidity conditions, ensuring the camera’s focal point remains optimally aligned. This reliability supports the long-term safety and efficiency of these critical systems.
 | GLUDITEC UV5103H Dual cure adhesive for Optical Component is a photo-curing cationic type and thermal-curing adhesive for the optical component. It is applied in various fields, such as C-MOS and it also provide low shrinkage and water absorption. With low viscosity and high thixotropic, this product is suited for dispensing equipment. |
In addition to the fast curing mechanism activated by UV or visible light, this adhesive can also react with moisture in shaded areas to complete the curing process. This type of adhesive is commonly used in PCB surface coating applications due to its flexibility in production, making it suitable for a wide range of industries, including medical devices, automotive, and electronics.
 | HumiSeal® UV40 is a high-performance, single-component, UV-curable acrylated polyurethane conformal coating. With high solids content, it provides excellent protection for printed circuit boards (PCBs) through superior chemical resistance, surface hardness, flexibility, and moisture resistance. |
 | ELPEGUARD® Twin-Cure® DSL 1600 E-FLZ The ELPEGUARD® thick film coatings of the series Twin-Cure® DSL 1600 E-FLZ are used to protect and insulate electronic assemblies so that they can fulfill higher requirements regarding reliability and service life. Owing to their very good resistance against moisture and condensation excellent protection against corrosion (such as electro-corrosion and migration) is possible even under harsh climatic conditions. |
UV cyanoacrylate adhesive (UVCA)
In addition to the three main types of adhesives mentioned above, UV Cyanoacrylate Adhesive (UVCA) is a newly developed adhesive technology designed to meet the demand for a product that combines all the benefits of cyanoacrylate and UV adhesives. It cures instantly when exposed to UV or low-intensity visible light, integrates easily into production lines, and eliminates the need for secondary activators or catalysts. The adhesive in shaded areas or behind opaque materials naturally cures through a secondary moisture curing mechanism.
These adhesives are surface-insensitive and highly versatile, providing excellent adhesion on a wide range of surfaces, including rubber and plastics. They minimize blooming and stress cracking on sensitive surfaces such as polycarbonate and acrylic and can also bond polyolefin plastics when used with a primer. This advanced adhesive technology is ideal for high-volume bonding applications across various industries and is increasingly favored in the production of medical devices, cosmetic packaging, speakers, electronic components, and more.
Read more: UV-curable cyanoacrylate adhesives (UVCA) for medical devices
 | The Mxbon 21401 is α-cyanoacrylate adhesive, and it is specially formulated for the assembly of difficult-to-bond materials. It will highly polymerize with moisture in the air for a fast cure and meet the highest industrial standards. |
 | Permabond® 130UV is a revolutionary dual-cure cyanoacrylate adhesive that offers the best of both worlds: lightning-fast UV curing and reliable moisture cure for shadowed areas. |
UV dual cure adhesive not only offers flexibility during application but also ensures the quality of the final product. With its ability to cure quickly, provide durable bonds, and adapt to a wide range of materials, UV dual cure adhesive has become the preferred choice for manufacturers across various industries, from medical to electronics.
UV Dual Cure adhesive products are officially distributed to manufacturers at Prostech with the best prices. Prostech is a leading distributor of industrial materials and machinery in the world. With years of experience, Prostech has provided products to thousands of manufacturers worldwide. Not only does Prostech supply products, but we are also committed to creating the best value for our customers through support and expert advice on products to meet specific customer needs. Contact us by leaving your information below.
