Electrically conductive adhesive & grease

What is electrically conductive adhesive & grease?

Electrically Conductive Adhesive

Conductive adhesive is a type of adhesive that can conduct electric current between contact surfaces. They often contain conductive particles, such as silver, carbon, or copper, dispersed in a polymer matrix. When this adhesive is applied between two materials that need to be connected, it serves both as a mechanical bond and allows electric current to flow through.

Electrically Conductive Adhesive is commonly used in applications that require electrical connections where wires or other traditional connection methods cannot be used or are not preferred. These applications include bonding components on printed circuit boards (PCBs), repairing circuits, and connecting compact electronic devices in tight spaces or where high flexibility is needed.

Conductive grease

Conductive grease is a special type of grease designed to conduct electricity, enhancing electrical conductivity between contact surfaces while also aiding in heat dissipation from hot components away from the contact area. Additionally, it reduces friction and protects contact surfaces from corrosion and damage.

 

Common Conductive Adhesive and Grease Products

Conductive products are made from various chemical bases, resulting in different types of products depending on the application:

1. Electrically conductive silicone grease

Silver conductive grease provides maximum electrical and thermal conductivity, proven lubrication properties, and protection against moisture, oxidation, and other environmental damage. This type of conductive grease uses advanced silicone lubricants compatible with metals, rubber, and plastics. The product can be used to fill gaps in connectors, provide grounding for electrical circuits, and control electrostatic discharge.

Features and Benefits:

• Fills gaps in connectors to maximize electrical and thermal conductivity

• Maximum electrical and thermal conductivity

• Protection against moisture and corrosion

• Thermal stability across a wide temperature range

• Conductive lubricant containing pure silver

• Control of electrostatic discharge

• Grounding for electrical circuits

CircuitWorks Silver Conductive Grease CW7100	Momentive SilCool* TIG2000

 

2. Conductive Two-Part Epoxy 

This type of adhesive consists of epoxy resin and a hardener, containing conductive particles. When these two components are mixed, the adhesive cures, forming a rigid bond with electrical conductivity.

Features and Benefits:

• Conductive epoxy adhesives can have a wide range of viscosities, from low to medium to high, depending on the ratio of components and intended use. Low viscosity is suitable for applications requiring the adhesive to penetrate small gaps or evenly coat large surfaces, while high viscosity is often used when strong bonding is needed or when the adhesive needs to maintain its shape on uneven surfaces.

• For adhesives containing metallic particles, the resistivity can be as low as approximately 0.0001 Ohms∙cm.

PERMABOND® ET5453 Two-Part Epoxy	Gluditec ET5114 Two-part Epoxy for Bonding

 

3. Conductive One-Part Polyurethane

This is a newly developed adhesive in the market.

Features and Benefits:

• Excellent Electrical Conductivity and High Flexibility: Conductive polyurethane adhesive has good electrical conductivity, making it suitable for applications requiring electrical contact. At the same time, the adhesive offers high flexibility and good mechanical strength, ensuring a secure bond that can withstand stretching or deformation.

• Versatile in Applications and Storage Requirements: The adhesive can be applied using various methods such as dispensing, spraying, or manual application, and can cure at room temperature or with heat. To maintain stability, the adhesive should be stored in a refrigerator and protected from high temperatures or freezing.

PERMABOND PT326 Polyurethane Adhesive	Bostik Polytec PU1000

 

Criteria for selecting the right electrically conductive adhesive

To choose the appropriate electrically conductive adhesive, users should consider the following criteria:

1. Electrical conductivity

• Conductivity: The adhesive must have sufficiently high conductivity to ensure that signals or currents can be transmitted effectively. For applications requiring high conductivity, adhesives containing silver or carbon are often preferred.
• Volume Resistivity: Lower resistivity generally corresponds to better conductivity. The suitable resistivity value should be determined based on the application.

2. Viscosity

• Select an adhesive with viscosity and rheological properties that are appropriate for the adhesive application process and the stability requirements of the adhesive drop on the surface.

3. Adhesion

• Substrate Materials: The adhesive must have good adhesion to substrate materials such as metals, plastics, or ceramics. It is necessary to determine whether the adhesive can form a durable bond with these materials.
• Working Conditions: Conditions such as temperature, humidity, and operational environment can affect the adhesive’s bonding. It is advisable to choose an adhesive that can maintain a strong bond under these conditions.

4. Mechanical Properties

• Hardness: The adhesive needs to have suitable hardness to withstand mechanical impacts, vibrations, or deformations without losing its conductivity.
• Flexibility: For applications requiring flexibility, the adhesive should possess a certain level of elasticity to avoid cracking or breaking when shape or size changes occur.

5. Thermal Resistance

• Operating temperature range: The adhesive must operate effectively within the temperature range of the application. For applications requiring high temperatures, it is recommended to select an adhesive with good heat resistance.
• High/Low-Temperature Resistance: Applications requiring adhesives to endure extreme temperatures, both high and low, should not experience degradation or loss of conductivity.
  

6. Work Time and Cure Time

• Work Time: Depending on the production process, the adhesive needs to have a sufficiently long work time to handle and bond components without drying too quickly.
• Cure Time: The cure time should be determined to align with the production process, avoiding interruptions or delays in the assembly process.

7. Electromagnetic Interference (EMI) Shielding

• If the application requires control of electromagnetic interference, select an adhesive with effective EMI resistance. Adhesives containing conductive particles such as silver are commonly used for this purpose.

8. Regulations and Standards

• Safety Standards: Ensure that the selected adhesive complies with safety standards and environmental regulations related to the application, such as RoHS or REACH.
• Medical Applications: If used in medical applications, the adhesive must meet biocompatibility and health safety standards.

9. Cost and Performance

• Economic Efficiency: Consider the balance between performance and cost of the adhesive to ensure optimal selection for your application.

Choosing the appropriate conductive adhesive and grease solution depends on the specific requirements of the application and environmental conditions. Each product type offers unique advantages and meets different requirements in the production and use of products. With many years of experience in the field of adhesives and industrial materials, Prostech is ready to assist customers in selecting the right electrically conductive adhesive and providing solutions that integrate into production lines to optimize efficiency. Contact us for a free consultation.

 

Applications of electrically conductive adhesives

1. Chip bonding and soldering in the semiconductor Industry

Electrically conductive adhesives are commonly used to attach semiconductor chips to printed circuit boards (PCBs) as an alternative to traditional soldering. This helps reduce heat during the manufacturing process and is suitable for heat-sensitive components.

2. Connecting Surface-Mount Device (SMD) Components

In electronics manufacturing, electrically conductive adhesives are used to attach surface-mount devices (SMDs) to PCBs. This enhances mechanical durability and reduces the risk of damage from vibrations or impacts.

3. Bonding LCD and OLED Displays

Electrically conductive adhesives are used to attach the leads of LCD and OLED displays to the control boards, ensuring that electronic signals are transmitted without interference.

4. Electromagnetic Interference (EMI) and Radio Frequency Interference (RFI) Shielding

Conductive adhesives are used to create electromagnetic shields on electronic devices, minimizing interference from external magnetic fields and radio waves.

Read more about EMI shielding here. 

5. Connecting Batteries to Circuit Boards in Mobile Devices

Electrically conductive adhesives help bond batteries to circuit boards in mobile devices such as smartphones, tablets, and wearable devices, ensuring strong connections and effective power transmission.

6. Medical Applications

Conductive adhesives are used in medical devices such as ECG electrodes, helping to attach sensors to a patient’s skin and accurately transmit biological signals.

7. Repairing Electronic Devices

Electrically conductive adhesives are utilized to repair damaged electrical circuits or create new pathways on PCBs when necessary.

Prostech understands the technical issues related to conductive materials for PCB and electronic device manufacturers. We provide comprehensive solutions, including consulting, materials, and automation equipment for adhesive application. We have a worldwide network of warehouses to support customers with logistics procedures. Positioned as a comprehensive supplier, Prostech continually strives to be a trusted partner for manufacturers around the world. Contact us by leaving your information below:

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