Математичне моделювання процесу прогрівання пакета шпону, склеєного термопластичною плівкою
| Rok vydání: | 2020 |
|---|---|
| Předmět: |
0106 biological sciences
Pressing chemistry.chemical_classification Thermoplastic Materials science medicine.medical_treatment Composite number Thermosetting polymer 02 engineering and technology 021001 nanoscience & nanotechnology 01 natural sciences Low-density polyethylene Thermal conductivity chemistry 010608 biotechnology medicine lcsh:SD1-669.5 General Earth and Planetary Sciences Veneer Adhesive lcsh:Forestry Composite material лущений шпон поліетилен низької густини теплопровідність питома теплоємність щільність пакета температура текучості 0210 nano-technology General Environmental Science |
| Zdroj: | Науковий вісник НЛТУ України, Vol 30, Iss 3, Pp 93-98 (2020) |
| ISSN: | 2519-2477 1994-7836 |
| Popis: | A promising variety of the wood composite materials is plywood glued with thermoplastic polymers. However, making such a wood composite requires adjustment of the pressing modes, because there is a slight difference between the hot method of pressing veneer packages glued with thermoplastic films and the method of pressing the veneer packages glued with thermosetting adhesives. Among the main processes that occur in plywood gluing are heat and mass transfer. The availability of the thermoplastic film between the veneer sheets is going to change the thermal conductivity of the package, and therefore will affect the pressing duration. If suppose, that the package has a plate appearance, which is located between heated to the certain temperature pressed plates, then the known Fourier-Kirchhoff thermal differential equation could be applied. The basis for the model development of the warming package veneer glued with thermoplastic film is laid in the methods of nonlinear programming, uniform search and conjugate gradient. On the offered mathematical model basis, the temperature field change in the package thickness during the plywood gluing with plastic film is calculated, the calculation of the warming duration indicators of the veneer package is done and this indicator dependence on the thermoplastic film flow rate and the pressing temperature is defined. The duration of the warming veneer package glued with thermoplastic film depends on the temperature at which the thermoplastic polymer will change from a highly elastic to the viscous state. The transition of the thermoplastic film LDPE to the viscous state begins at 125 оС and lasts up to 240 оС. With increasing of the press temperature plates from 140 to 180 оС the duration of warming up the middle of the package to 125 оС decreases by 89 % for all investigated polymer costs is defined. Changing the polymer content in the package does not significantly affect the duration of its warming. With increasing of the thermoplastic film flow rate from 130 g/m2 to 190 g/m2, the duration of warming up the middle of the veneer package to 125 оС increases slightly from 3.8 to 4.2 % depending on the pressing temperature. To verify the validity of the model, experiments to measure the temperature inside the veneer package during its pressing were carried out. The values of theoretical and experimental dependencies are close, which confirms the adequacy of the developed model. |
| Databáze: | OpenAIRE |
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