Herasymenko Yuliia. Equipment and process of connecting flexible packaging elements with thermoplastic adhesive material. – Qualifying scientific work on the rights of the manuscript.
A thesis for obtaining a scientific degree of a Ph.D on specialty 131 – “Applied Mechanics”. – National Technical University of Ukraine “Igor Sikorsky Kyiv Polytechnic Institute”, Kyiv, 2023.
The dissertation is devoted to the study of equipment and processes for the preparation of thermoplastic adhesive material (hot-melt adhesive), the formation of a hot-melt adhesive connection of packaging elements, and its mechanical characteristics, which makes it possible to substantiate rational technological regimes necessary for the design and operation of packaging equipment.
The technology of joining with thermoplastic adhesive material is widely used in the chemical, food, and textile industries for the formation of joints in cardboard, paper and polymer packaging. To meet the needs of consumers, it is necessary to ensure a sufficient level of packaging strength and ease of use. Therefore, when creating durable high-quality packaging, it is important to pay special attention to the correct selection of materials and equipment, as well as the preparation of the thermoplastic adhesive melt and the process of connecting surfaces.
An analytical review of the current state of the study of the melting process of thermoplastic adhesive material (hot-melt adhesive) and the process of destruction of a thermo-adhesive joint during its opening has been carried out. Existing methods for modeling equipment and the process of melting hot-melt and forming a hot-melt joint are considered.
The considered modern designs for melting and applying hot-melt adhesive have several disadvantages, for example, a slow melting process and its unevenness, as well as the insufficient intensity of acquiring the melting temperature by the polymer material.
To simulate the melting process of hot-melt adhesive, a mathematical model of the non-isothermal motion of a polymer melt in a channel was used. The problem of transition from a solid to a viscous-flow state and back has been solved.
Investigations were carried out on the melting efficiency of a hot-melt adhesive rod in melters of four configurations: a cylindrical shape, the existing configuration a cylindrical shape with a nozzle, a tubular shape with a mandrel, and a screw type.
The results obtained showed the feasibility of using an improved configuration of the hot-melt stick. Rational geometry is determined from the point of view of the highest heating intensity of the bar. A study of a melter with a tubular rod configuration has shown that it can increase productivity by 2,4 times while maintaining energy consumption compared to a traditional configuration.
A more rational design of a screw-type thermoplastic adhesive melter with a prefabricated rod in the form of a tape is proposed. The advantages of the proposed design over the existing ones are: increasing the melting rate of the polymer material, reducing the size and weight of the device, reducing energy consumption and ease of use.
To study the melting process of hot melt in the screw channel, a computer calculation model based on the finite element method was developed and numerical calculations were made. As a result of the calculations, the temperature distribution along the length of the channel along the axis of the screw was obtained for different values of the angular velocity of the screw. Dependences have been obtained that make it possible to control the temperature of the hot-melt adhesive at the outlet of the heating channel and the consumption of material when changing the values of the screw speed.
The process of formation of a hot-melt adhesive seam under the action of pressing force and cooling is simulated. The dependence of the shape of the seam on the value of the pressing force and the consumption of hot-melt adhesive material is predicted. The simulation results are confirmed experimentally.
To simulate the process of destruction of an adhesive joint, a mathematical model of the adhesion zone based on continuum mechanics was used with the use of strength and energy parameters to predict the propagation of a crack in the joint.
The connection between the consumption of hot-melt adhesive and the strength of the hot-melt adhesive was experimentally established, and the most appropriate consumption value from the point of view of strength was obtained. It has been established that the strength of the adhesive joint does not depend on the width of the seam.
Improved designs of the device for melting and applying hot-melt adhesive are protected by utility model patents of Ukraine.
Experimental studies of the tensile strength of tape samples of flexible packaging materials connected by hot-melt adhesive were carried out.
