Hot melt adhesive film is widely used as an industrial adhesive in many industries. Still, because of its wide range of applications, it is also highly specialized, and the requirements for hot melt adhesive film vary from industry to industry. Hence, the performance parameters involved are also different. Melt index is an important parameter of hot melt adhesive film, but most people do not know this parameter very well, so here is a brief introduction.
The melt index is an indicator of the fluidity of the hot melt film after melting, which affects the coating, wetting, and penetration of the adhesive on the surface of the glued material. Melt index can be closely related to the hot melt adhesive process.
The melt viscosity is closely related to the temperature, it grows as the temperature decreases, so it must be measured at a certain temperature. Generally, 190±2°C is the temperature at which it is measured. A rotary viscometer can directly measure the low melt viscosity of hot melt adhesive film. The measurement is the melt viscosity. The measurement method is: put 500ml of pre-melted hot melt adhesive sample into the drum of the viscometer, and keep it for 5min at the measurement temperature (190±2℃), then let the rotor rotate for 30-60s and take the reading. For the high melt viscosity of hot melt adhesive film, usually is the determination of the thermal melt index, is to use a special melt index tester determine. The measurement method is: the molten glue of 190±0.4℃ is poured into the drum of the measuring instrument, and then pressed down with a punch of weight 2160±10g, and measured the number of grams of glue being squeezed out of the small hole at the bottom of the drum within 10min, which is the melt index. The melt viscosity and melt index have the corresponding conversion relationship.