Views:10 Author:Site Editor Publish Time: 2019-09-23 Origin:Site
The determination of the composition of the hot melt glue adhesive and its amount depends mainly on the availability of properties that meet the requirements of the application. At the same time, the performance of the glue used must also be fully understood when using hot melt PA glue adhesive to determine the appropriate conditions of use.
Today we share the melt viscosity of hot melt polyamide glue adhesives and hope to help you.
Melt viscosity is a performance index that reflects the flow properties of hot melt adhesives. It directly affects the coating, wettability and permeability of the colloid on the adherend, and also affects the drawing phenomenon of the adhesive. Therefore, melt viscosity is an important basis for determining the melting and coating process. Melt viscosity is closely related to temperature, it increases with decreasing temperature, so it must be measured at a certain temperature. The measurement is generally carried out at an average temperature (190 ± 2 ° C) when the hot melt adhesive is used.
The hot melt adhesive of low melt viscosity can be directly measured by a rotary viscometer. Measuring method : 500 ml of the pre-melted hot melt adhesive sample was placed in a drum with a viscometer, held at the measured temperature (190 ± 2 ° C) for 5 min, and the rotor was rotated for 30-60 s, then reading.
For high melt viscosity hot melt adhesives, the hot melt index is usually determined and measured using a special melt index meter. Measuring method : The molten glue of 190 ± 0.4 ° C was poured into a drum of the measuring instrument, and then pressed with a punch having a weight of 2160 ± 10 g, and the number of grams of the small hole in the bottom of the drum was measured in 10 minutes.
In order to obtain a better bonding effect, we should choose the hot melt adhesive with suitable melt viscosity according to the material of the substrates, the shape of the surface, etc.