PCB adhesive plays a critical role in electronics, more than a simple glue to bond components together. It also offers a variety of functions in electronic applications, including insulation, thermal management, structural support, protection, etc. This blog introduces the top eight circuit board adhesive types and explores their common applications in modern electronic manufacturing. Read on to find out which PCB adhesive type best fits your design and manufacturing needs.
Top 8 PCB Adhesive Types
PCB adhesive comes in different types, each featuring unique properties for bonding, insulation, or heat management. In this part, we will explore the top eight commonly used circuit board glues in PCB manufacturing.
Ultraviolet-Curing Adhesive
Nowadays, UV-curing adhesive is getting more and more popular, thanks to its fast curing time, excellent bonding capabilities, and environmentally friendly properties. It’s a kind of light-activated PCB glue that is quickly and instantly cured under the ultraviolet light. The curing speed is affected by light intensity and chemical formulation. Ultraviolet-curing adhesive is commonly used in various applications, including encapsulants for component protection, bonding adhesives for PCB assembly, and coatings for surface protection. For high-speed, large-scale production, Ultraviolet-Curing Adhesive can be an ideal option.
Some Pros:
- Faster curing time, improving assembly efficiency.
- Minimize the energy consumption.
- Low Volatile Organic Compound (VOC) content, beneficial for the environment and health.
- Easy to scale up manufacturing by adding more lamps on the production line.
Some Challenges:
- Lighting type is not compatible with adhesive formulation.
- Inadequatecure time due to the manufacturing process.
- Improper storage causes premature curing.
- Adhesive failure with the wrong substrate.
Thermally Conductive Adhesive
Thermally conductive glues have excellent heat dissipation capacity, ensuring component longevity. They can be used to bond the heat sinks to the components, offering an effective, direct heat dissipation channel. To increase their thermal conductivity and thickness, these adhesives are often blended with conductive or insulating fillers. Generally speaking, thermally conductive adhesive is ideal for heat-intensive applications, such as LED, CPU, power devices, and processors.
Electrically Conductive Adhesive
As the name suggests, this PCB adhesive not only can bond but also allow electrical connections. Electrically conductive adhesive is available in two types: isotropic conductive adhesive, which conducts in every direction, and anisotropic conductive adhesive, which allows for one-way conduction. Compared with PCB solder, it doesn’t need to remove PCB flux residue, significantly simplifying the assembly process. Furthermore, electrically conductive adhesives can assist in EMI shielding, RFI, and ESD protection. Silver-filled adhesive is the best for shielding, followed by the nickel-filled one. Graphite-filled adhesives are less effective, but are sufficient for ESD protection.
Epoxy Adhesive
Epoxy glue is popular in the PCB industry, cured by the activation between the curative hardener and epoxide. It offers reliable and strong bonding, which is commonly used to bond multilayer PCBs. Besides, the epoxy adhesive has good chemical resistance and fatigue resistance and can withstand extreme moisture and temperatures. With these properties, this PCB adhesive is perfect for industrial and aerospace applications. To meet the different flexibility and thermal shock resistance requirements, the formulations of epoxies can be changed.
Acrylic Adhesive
Acrylic glue offers a strong yet flexible bond, making it suitable for PCB applications exposed to vibration or mechanical stress. It can be quickly cured in seconds under UV light. Moreover, this PCB glue can be stored at room temperature before use, providing convenience during assembly. Although acrylic has slightly lower heat resistance than epoxy, its fast curing and versatility (flexibility, bond strength, and temperature resistance) make it ideal for dynamic applications such as automotive and consumer devices.
Polyimide Adhesive
Polyimide adhesive is famous for withstanding extremely high temperature (up to 300℃)， making it popular in industrial, aerospace, automotive electronics, etc.
Silicone Resins Adhesive
Silicone resins are commonly used for conformal coatings or encapsulants. This PCB adhesive has excellent flexibility and extreme temperature tolerance (from -60ºC to +200ºC). Compared with epoxies, the bond strength is lower. With heat resistance and flexibility, it’s an ideal option for high-flex PCBs used in automotive electronics or wearables.
Cyanoacrylates (Super Glue)
Cyanoacrylates, also called super glue, are usually used to attach the wires to the circuit board. In PCB assembly, it typically applies to quickly stick the light and small components, which is beneficial for a high-speed manufacturing process. This kind of PCB adhesive can be cured quickly, which dries faster, especially when cooperating with activators. However, it has a limitation in high-vibration environments due to its brittleness. In high-moisture situations, its stable capacity is poor and sensitive to moisture.
PCB Adhesive Comparison Table
| Adhesive Type | Cure Mechanism | Flexibility | Key Strengths | Key Disadvantages | Typical Applications |
| UV Curing | UV | Low – Medium | Fast curing speed | Requires UV equipment, incomplete curing in shaded areas | High-speed manufacturing, SMT components |
| Thermally Conductive | Heat / UV / Mix | Low | Excellent heat dissipation | Thick, higher cost, | Heat-sensitive applications, overclocked CPUs, gaming setups, |
| Electrically Conductive | Heat | Low | Provides electrical path; solderless connection | More costly than soldering | Flexible PCBs, wearables, touchscreens |
| Epoxy | Heat / Mix | Low (Rigid) | High bond strength, long-lasting, good chemical resistance | Extended curing time, hardens after drying | Multilayer PCBs, securing large parts and mechanically stressed areas |
| Acrylic | Heat / UV / Air | Medium | Strong bonds, fast cure speed, | Lower heat resistance than epoxy | Automotive electronics, consumer devices |
| Polyimide | Heat | High | Extreme heat resistance | Needs specialized curing | Industrial, aerospace, automotive |
| Silicone | Heat / Moisture | High | High temperature tolerance (-60°C to +200°C), high flexibility | Lower bond strength than epoxy | Conformal coating, encapsulants, high-vibration environments |
| Cyanoacrylates | Moisture | Low (Brittle) | Fast curing, easy to apply | Moisture sensitive, brittle | Wire attachment, temporary fixes |
Common PCB Glue Applications
PCB adhesive is not just for sticking components, but also provides a versatile solution. Let’s explore their actual application and learn how they ensure the devices operate stably.
PCB Conformal Coatings
PCB conformal coatings serve as a protective shield to protect the circuit board against moisture, corrosion, dust, etc. Besides, the coating also helps to avoid short circuits and prevent corrosion. The commonly used PCB board glue for conformal coatings includes acrylic, silicone, and epoxy.
Encapsulating And Potting
The potting is applying the PCB adhesive to the small space of the PCB, avoiding environmental and physical damage. Epoxy, silicone, and acrylic are frequently used in the potting process.
Wire-Tacking Adhesive
With PCB adhesive, the wire-tacking will become easy. You can use acrylics, epoxies, and cyanoacrylates to attach wire to the objects. Cyanoacrylates are the most popular option, only requiring 30 seconds to cure.
Chip Holding
PCB glue can hold the tiny SMD components on the board. It can avoid any movement of SMDs before soldering.
Lamination
In multilayer PCBs, circuit board glue can bond fiberglass layers together, ensuring tight connections under the heat and pressure.
Final Words
Each PCB adhesive type offers distinct advantages, from fast-curing UV glues to heat-resistant polyimide and flexible silicone options. The right choice depends on factors such as bonding strength, flexibility, and operating temperature range. Selecting the proper PCB board glue not only enhances high performance and reliability but also extends the service life of your electronic products. If you’re still unsure which circuit board adhesive best suits your application, contact MOKOPCB for professional guidance and tailored recommendations.
