What is conductive adhesive and how it can be divided?

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Conductive adhesive is a kind of adhesive that can both effectively bond various materials and have electrical conductivity. It can be divided into two categories: isotropic homogeneous conductive adhesive (ICA) and anisotropic conductive adhesive (ACA). ICA refers to the adhesive that is conductive in every direction; while ACA is different, for example, Z-axis ACA refers to the adhesive that is conductive in Z direction and will not be conductive in X and Y directions. Currently, researches are mainly concentrated on ICA.

conductive adhesive fillerAccording to the matrix composition, conductive adhesive can be divided into structural type and filled type. In the structural conductive adhesive, the high polymer material that is used as the matrix of conductive adhesive will have electrical conductivity itself; in the filled type conductive adhesive, the ordinary adhesive will be used as the matrix, which will have electrical conductivity after being added with conductive filler. At present, the preparation of conductive polymer material is very complex and still has a large distance from the practical application. Therefore, filled conductive adhesive is widely used.

Metal powder is generally used as the conductive filler in the filled type conductive adhesive. As different varieties, particles, structures and quantity of metal powders as well as different adhesive substrate are used in the conductive adhesive, its varieties and performances will vary a lot. Currently, silver powder filled conductive adhesive is commonly used. Beside, copper powder filled conductive adhesive can be used in some situations that require low electrical conductivity.

According to the matrix composition, the filled conductive adhesive that is being used in the market currently can be divided into following categories: epoxy conductive adhesive, of which the base material is epoxy resin and the filled conductive metal particles mainly include Ag, Ni and Cu (Ag plating); silicone conductive adhesive, of which the base material is silicone and the filled conductive metal particles mainly include Ag, Ni and Cu (Ag plating); polymer conductive adhesive, of which the base material is polymer and filled conductive metal particle is Ag.