Adhesive academy is back in session and everyone is excited. Watch as Dr. B explains how viscosity can be modified with the addition of fillers or heat and the importance of flow to meet specific application requirements. Learn how these adjustments can improve productivity and performance for you. Learn how these adjustments can improve productivity and performance for you.
Sam: Hi Dr. B. This latest inquiry was about how to adjust viscosity in an existing adhesive, without replacing the formulation being used.
Dr. B: Viscosity is generally a function of the temperature at which the product is applied. If you were to pre-heat the substrates or the compound itself, this process would influence the viscosity. However, a potential trade-off might be the reduction of its working life.
Sam: What about using thinning agents?
Dr. B: Thinning agents or reactive diluents are a possibility in certain cases, depending on the type of adhesive used. The trade-off here could involve a loss of some desirable cured properties, such as chemical or temperature resistance.
Sam: How can the viscosity of the product be increased in order to lessen the flow?
Dr. B: Inert fillers can sometimes be added to increase the viscosity. The amount of filler and particle size distribution are essential in controlling flow characteristics. One commonly used thickening agent is fumed silica, which helps to increase the viscosity significantly.
Sam: Are fillers used to enhance any other properties of the compound?
Dr.B: Some thermally conductive fillers help not only to increase the viscosity, but also to dissipate heat while other fillers are designed to improve machinability, corrosion resistance, flame retardancy and thermal stability.
Thanks Dr. B. I am going to call back these engineers now to discuss the best viscosity option for their application. I’ll keep you posted!
Compounds can be formulated in a range of viscosities and other superior performance properties.