Electronic adhesives offer numerous advantages, including the ability to firmly bond materials of the same or different types, the absence of stress concentration at bonded joints, high bonding strength, and ease of integration into automated processes. Consequently, they have been widely adopted across diverse applications—particularly as one of the auxiliary materials in electronic industrial production. Given the growing demands for miniaturization, lightweighting, and enhanced performance of electronic products, the variety and usage of adhesives in the electronics industry have not only expanded significantly but also exhibited progressively superior performance characteristics. Due to the wide range of available electronic adhesives, stringent performance requirements, and high added value, these adhesives occupy a pivotal position within the adhesives industry.
1.Requirements for electronic adhesives
The following are the key characteristics of electronic adhesives:
2.Main types of electronic adhesives
1. General-purpose adhesive
The term “universal adhesive” refers to an adhesive capable of bonding a variety of metals, plastics, and other materials, including the following types:
- Second-generation acrylate adhesive
It is available in two types: dual-component and base-resin formulations, characterized by rapid curing and high bonding strength.
- α-Cyanoacrylate adhesive
It is a representative example of quick-setting adhesives. It can bond to most materials; when used in conjunction with a base adhesive, it can even bond polyolefins and engineering plastics.
- melt adhesive
The primary varieties include EVA, polyamide (nylon), and polyester. EVA thermoplastic adhesives are widely used, although they exhibit poor heat resistance, whereas the latter two types offer superior heat resistance. The greatest advantages of thermoplastic adhesives are their rapid curing speed and lack of environmental pollution.
- Organic silicone adhesive
Organic silicone adhesives are primarily classified into two categories—single-component and two-component—each of which comprises numerous variants. In the electronics industry, single-component moisture-curable silicone adhesives are widely used. Their primary applications include: insulation sealing for high-voltage circuits; bonding and sealing of various electronic components, mixed integrated circuits, power supply assemblies, cathode-ray tubes, and other high-voltage components; as well as bonding and sealing of heat-resistant glass products.
2. Thermal conductive adhesive
When mounting components with high heat generation and specific thermal management requirements on electronic chassis or circuit boards, thermal paste is typically employed. For example, components such as transformers, transistors, and CPU chips are commonly bonded to the chassis, the cold plate of the circuit board, or a heat sink using thermal paste.
Thermal conductive adhesives are typically single-component compounds. High-quality thermal conductive adhesives not only exhibit excellent thermal conductivity, resistance to thermal cycling, aging resistance, and electrical insulation properties, but also demonstrate superior moisture resistance, vibration resistance, corona resistance, leakage current resistance, and chemical medium resistance. They can be continuously used within a temperature range of –60 °C to 280 °C while maintaining their performance, without swelling, and exhibit excellent adhesion to most metallic and non-metallic materials.
3. Conductive adhesive
In the field of microelectronic assembly, conductive adhesives are commonly employed to bond fine wires to printed circuits, plated substrates, metal layers of ceramic substrates, and metal chassis; to bond wires to sockets; to bond components to via holes penetrating printed circuits; to bond waveguides for tuning; and to perform via repair. Depending on the curing system, conductive adhesives can be classified into room-temperature curing conductive adhesives, medium-temperature curing conductive adhesives, high-temperature curing conductive adhesives, and UV-curable conductive adhesives.
conductive adhesive
- pouring sealant
When performing bonding, sealing, potting, and protective coating of electronic components, potting compounds are commonly employed. In their liquid state before curing, these compounds, once cured, provide functionalities such as waterproofing, moisture resistance, dust protection, electrical insulation, thermal conductivity, sealing, corrosion resistance, temperature resistance, and shock resistance.
By material type, the three most commonly used and widely adopted types currently in use are epoxy resin potting compounds, silicone resin potting compounds, and polyurethane potting compounds.
Electronic Adhesives: Separate Electrical, Thermal and Mechanical Duties
The selection of electronic adhesives becomes clearer when each material is assigned a specific assembly duty. A bond that holds a component, an interface that transfers heat and a layer that excludes moisture are not interchangeable simply because they surround the same circuit. Mark the required electrical behavior first. An electrically conductive joint must maintain the intended connection, while an insulating adhesive must avoid creating unwanted conductive paths. Thermal conduction is a separate property: a material can be used to transfer heat without being intended to carry current. Verify the selected formulation’s behavior instead of inferring it from the filler name or the generic resin family. Next, review the load introduced into the component. A stiff bond can hold a part accurately, but shrinkage during cure and differential movement during heating can apply stress to a fragile package or board. A softer material can accommodate movement, yet it may need a separate restraint if the component must retain its position under load. Why ask a soft protective gel to perform the same task as a structural fixing adhesive? It’s more useful to divide the tasks and then assess how the materials interact. The potting and encapsulating compound range is relevant when the duty involves surrounding circuitry, rather than only joining mating surfaces. Filling a cavity changes access to the components and can change the thermal path as well as the mechanical environment. Preserve features that must remain open, including designated vents, connectors and sensing openings. Consider rework at the selection stage: a removable protective layer and a rigid encapsulated assembly create different maintenance options. Also inspect the real surface being bonded. Solder residues, protective coatings and mold-release contamination can affect adhesion or curing. A trial on clean bare metal may therefore say little about a coated production board. Document the substrate surface, required function and assembly constraints before comparing adhesives on the basis of a single property.
Control cure and trace defects to their actual origin
When evaluating electronic adhesives, begin with compatibility specimens that include the surfaces and neighboring materials found in production. A material may cure normally in isolation but cure poorly where it contacts a residue or another compound. For addition-curing silicone formulations, contamination can interfere with the curing system, so unexplained uncured regions deserve investigation at the contact interface. This does not apply identically to every silicone chemistry. Mixed adhesives require the selected material’s specified preparation method; mixing proportions and dispensing equipment should not be transferred from another formulation merely because both products belong to the same family. Reactive curing can release heat, with the actual temperature rise influenced by the amount and geometry of material being cured. A thin bond trial may not reveal what happens in a filled enclosure. Evaluate the intended fill geometry while respecting the material’s processing instructions and component limits. Light-curing materials introduce another dependency: the joint needs access to the appropriate light, including areas obscured by components. Do not assume that a cured exposed bead proves complete cure behind an opaque part. Inspect representative sections where necessary and assess the assembly after the complete curing process. For thermally active components, the thermally conductive adhesive category can support an interface discussion, with the heat path and attachment method identified. Electrical and thermal checks should then be performed on the assembled hardware. Compare function before and after relevant environmental conditioning, keeping measurement conditions consistent. Look for interface separation, cracked material, trapped voids and changes in component positioning. A defect at a wire entry may follow a different moisture path from a defect under a heat sink. Record the location rather than assigning every failure to insufficient adhesive strength. If the board surface, connector material or assembly sequence changes, revisit the corresponding compatibility or curing check. A clear record of material identity, surface condition, application method and failure location makes corrective work more targeted. It also helps prevent a change in production handling from being mistaken for a limitation of the adhesive family.
Selection of the right grade from the full JOME product catalogue usually starts with drawings and service conditions. The companion piece on Introduction to Adhesives Do You Really Understand sits alongside this guide, the JOME adhesive product homepage lists every family, and the share your requirements with JOME handles enquiries.