(1) Non-active diluent this diluent molecule does not contain the active group, mostly is the inert solvent, such as ethanol, acetone, toluene and so on ⑵ in the dilution process does not participate in the reaction, it only blends in the resin and reduces the viscosity the goal. In addition to the dilution effect, the mechanical properties, thermal deformation temperature, medium and aging damage are affected. Should take into account the volatile rate of solvents, if the volatile speed is too fast, the surface of the adhesive layer is easy to form a film, hindering the internal solvent of the rubber layer escape. Causes the bubble to produce in the rubber layer, if the volatile speed is too slow, then in the gum layer to leave the solvent, thus will affect the bonding strength. It is usually used to adjust the volatilization rate by mixing several solvents with different boiling points. It is used in rubber-type adhesives, phenolic adhesives, polyester adhesives and epoxy adhesives.
(2) Active diluent is a diluent containing active groups in the molecule. It is in the process of diluting the adhesive to participate in the reaction, but also can play a toughening role (such as in epoxy adhesives added glycerin epoxy resin or propylene oxide butyl ether can play a toughening effect).
Active diluent is used in epoxy adhesives, and other types are used less.