STUDY OF THE THERMAL GLUE JOINT FORMATION PROCESS

Abstract

Purpose. Develop a numerical method for predicting the thickness and width of a hot-melt joint under the action of mechanical force and cooling, as well as investigate the effect of pressing force and hot-melt adhesive consumption on the joint width, which affect the strength and tightness of the hot-melt joint.

Methodology. To predict the formation of a hot-melt adhesive seam under the action of mechanical force and cooling, a computer calculation model was developed and a numerical calculation was made of the distribution of temperatures and deformation of the hot-melt adhesive layer from the pressing force of the rolls and the consumption of hot-melt adhesive. The results of numerical simulation are confirmed experimentally using the created pilot plant for hot-melt bonding.

Findings. A mathematical model of the process of polymer melt cooling and its deformation is proposed taking into account the Cross viscosity law on the strain rate and the dependence of viscosity on temperature. The initial and limiting conditions that determine this process are established by calculation and experiment. The dependences of the seam width on the pressing force of the rolls, as well as the dependence of the seam width on the consumption of hot-melt adhesive, are obtained. It has been established that with an increase in the consumption of hot-melt adhesive, the width of the seam increases according to a logarithmic dependence. With an increase in the pressing force of the rolls, the width of the seam increases according to a quadratic dependence.

Originality. The influence of the clamping force of the rolls and the consumption of hot-melt adhesive on the width of the seam is determined. It has been established that with an increase in the clamping force from 10.5 N to 20.5 N, the width of the seam increases from 8 mm to 17 mm (almost twice).

Practical value. Numerical modeling of the formation process of a hot-melt adhesive allows predicting the optimal values of the hot-melt adhesive consumption and the clamping force of the rolls to obtain the required seam width, which provides the optimum joint strength for the consumer, and is sufficient to maintain the tightness of the package.