Besides resin and curing agent, fillers are the most common ingredient in an adhesive formulation. Depending on the type of filler employed, it can have varied effects on the epoxy system. They can improve machinability, mechanical strength properties, corrosion resistance, thermal stability, abrasion resistance and dimensional stability. Specific fillers are capable of providing exceptional flame retardancy, heat dissipation properties and electrical conductivity.
Types of Fillers 1. Metallic Fillers: Metallic fillers include aluminum, silver, nickel, silver coated nickel and tungsten. Depending on the filler loading, they could provide first-rate electrical conductivity. Some of the popular electrically conductive systems include, TUF 1820 HTS (silver filled), KB 1031 ATFL-N (nickel filled) and KB 1689 (silver coated nickel filled). 2. Ceramic Fillers: Ceramic fillers include aluminum oxide, aluminum nitride, quartz, boron nitride and silicon carbide. Depending on the filler loading, they could provide superior thermal conductivity, dimensional stability and abrasion resistance. Some of Kohesi Bond’s popular ceramic filled systems include, TUF 1820 AOHT (alumina filled), KB 1040 AN-1 (aluminum nitride filled) and KB 1040 QF (quartz filled). 3. Other Fillers: Other fillers include graphite, glass spheres, carbon black, barium sulfate, pigments and other nanofillers. These fillers could offer many advantages to the epoxy system depending on their loading concentrations. Kohesi Bond KB 1085-1 is one such popular product that is graphite filled. Additionally, pigments can be added to color match to our customer’s specifications.
Effect of Fillers on Epoxy Properties Fillers are capable of transforming an epoxy to have much superior performance. They are capable of affecting the viscosity, shrinkage, pot life and exotherm. In addition, they can affect mechanical properties of an adhesive, such as tensile strength, compressive strength, abrasion resistance, dimensional stability, hardness, impact resistance and flexural strength. Also, they can affect the epoxies thermal and electrical properties. They could impart thermal as well as electrical conductivity, offer better thermal stability, arc resistance and dielectric properties. Pigments are added to color match the epoxy to the end user’s specifications. Some fillers offer radio opacity or even block light in specific wavelengths.
Kohesi Bond offers a wide range of adhesives, sealants, coatings, potting and encapsulation compounds that contain numerous fillers, to ensure superior performance in your application. Our technical experts custom formulate these products to your exact specifications.