How to choose the right material for conductive adhesive products?

Choosing the right conductive adhesive products materials, need to integrate a variety of factors to consider, the following are some specific points of choice:

Conductive properties:

• Resistivity requirements: according to the specific application scenarios on the demand for conductive properties, select the conductive adhesive products with the appropriate resistivity. For example, in the extremely high conductivity requirements of microelectronics packaging, precision instruments and other fields, should give priority to the selection of very low resistivity materials, such as silver powder as conductive filler conductive adhesive; for some conductivity requirements are relatively not so high for ordinary electronic equipment connection or shielding and other applications, such as copper powder and other filler conductive adhesive may be able to meet the demand.
• Conductive stability: to ensure that conductive adhesive products in different environmental conditions (such as temperature, humidity changes) are able to maintain stable conductivity. Some conductive fillers may be in a particular environment will be oxidized, corrosion and other phenomena, thus affecting the conductive properties, such as copper powder in the air is easy to oxidize, if the use of high humidity or long-term exposure to the air, you need to carry out a special surface treatment of the copper powder or choose a better antioxidant conductive filler.

Bonding performance:

• Adaptability to the adhered material: different conductive adhesive products have different affinity to the adhered material, and need to be selected according to the type of adhered material. For example, for plastics, rubber and other materials, it may be necessary to choose a matrix resin with good compatibility with these materials; for metal materials, it is necessary to ensure that conductive adhesive products can form a good bond on the metal surface, and will not affect the bonding effect due to the surface characteristics of the metal (such as roughness, oxidation layer, etc.).
  Adhesive strength: according to the application of the scene in the size of the external force, select the conductive adhesive products with sufficient bonding strength. For example, in some of the need to be often subjected to vibration, impact equipment, such as automotive electronics, aerospace equipment, etc., you need to choose a high bonding strength, good impact resistance of the conductive adhesive; and for some static electronic equipment, the bonding strength requirements can be relatively reduced.
• Curing conditions and time: different conductive adhesive products curing conditions and curing time varies, according to the actual production process and the use of requirements to choose. Some conductive adhesive needs to be cured at high temperatures, which may not be resistant to some of the adhesive materials caused by the damage, at this time you need to choose room temperature curing or medium temperature curing conductive adhesive; at the same time, the curing time will also affect the efficiency of the production, for the case of large-scale production, you should choose the conductive adhesive with a shorter curing time.

Environmental adaptability aspects:

• Temperature adaptability: consider the temperature range that conductive adhesive products may face during use. If the application environment temperature is high, such as in the high temperature electronic equipment or automobile engine nearby, you need to choose high temperature conductive adhesive products, its matrix resin and conductive filler should have good heat resistance; if used in low temperature environment, such as outdoor electronic equipment in the winter, you need to choose the conductive adhesive with good low-temperature resistance to ensure that at low temperatures will not become brittle, cracking, affecting the conductive and bonding properties.
• Humidity and water resistance: For some application scenarios that may come into contact with water or in a humid environment, such as outdoor electronic displays, underwater equipment, etc., you need to choose conductive adhesive products with good water resistance and moisture resistance. This requires that the matrix resin has a good sealing, to prevent water penetration into the conductive adhesive products, affecting the conductive properties and bonding strength.
• Chemical stability: If the conductive adhesive products will come into contact with some chemicals, such as acids, alkalis, organic solvents, etc., you need to choose a good chemical stability of the material to ensure that in contact with these chemicals will not occur when the chemical reaction, resulting in a decrease in electrical conductivity or bonding failure.

Process, cost, safety aspects:

• Cost: different conductive adhesive products material cost difference is large, under the premise of meeting the performance requirements, should try to choose lower cost materials to reduce production costs. For example, silver powder as a conductive filler conductive adhesive excellent performance, but the price is higher, if the conductivity requirements are not particularly demanding, copper powder and other relatively inexpensive conductive filler may be a more economical choice.
• Safety: conductive adhesive products in the use of the process should ensure that safe and reliable, does not contain substances harmful to human health. For example, some solvent-based conductive adhesive products may release volatile organic compounds (VOC), harmful to human health and the environment, in the selection should be given priority to low VOC or no VOC products.
• Construction process: according to the specific requirements of the construction process to select the appropriate conductive adhesive products. For example, if the dispensing process, you need to choose a moderate viscosity, good fluidity of the conductive adhesive, in order to facilitate accurate dispensing; if the coating process, you need to choose a good coating performance, moderate drying speed of the conductive adhesive.