Curing Reaction Dynamics Of The Amino Baking Finish Under Infrared Radiation

The amino baking finish is widely applied to industry, such as machinery, electrical machinery, electric appliance, measuring appliance, automobile and so on. During the amino baking finish drying solidification process, if using the tradition heats, the time is long, efficiency is low, and too much energy is wasted, but the far infrared radiation heating way has two merits: the elevation of temperature much more rapid, the direct heating object to avoid the energy losing. It is a highly effective way for heating. The main principle of the far infrared radiation heating is the match-absorption principle, when the frequency of the infrared shining on the object is the same with the molecules', the molecules will absorb the energy of the far infrared, and the energy will transfer between molecules by impact with others. Then the molecular internal energy (vibrational energy and rotational energy) increases, and we see the object's temperature increases. The match-absorption means that when the frequency radiated consists with the vibrational frequency of the molecules, the molecules will absorb the infrared's energy, the absorption here just is match-absorption. The match-absorption has very important significance about the thin layer heating, like baking varnish, plastic processing and certain salts dehydrations dry and so on. The mechanism of the infrared baking of varnish, it mostly depends on the radiation wave of the infrared and the paint membrane's molecular vibration wave, if the two are the same, the membrane high polymer molecules will have a intense molecular resonance, generate lots of heats, so to increase the speeds of the paint solvent drying and the resin solidification.Next is the detailed content, have two parts as follows:The first part: the voltage's effect on the solidification rapid of the amino baking varnish.In this paper, we use the opal quartz lamp radiating infrared to shine the amino baking finish, by changing the quartz lamp' voltage, we have collected the infrared spectrums of the amino baking finish which shined under the quartz lamp with different voltage. The graph 1 is the infrared absorption spectrum of the amino baking finish at the 180 volts voltage, from the graph, we can see, as the time going on, the 1733cm^-1 carbonyl peak stay as the same, so we can use this peak as the reference peak. The spectral band3128-3683cm^-1, intensity decrease obviously, we study at this band: after shining a moment, we have calculated the percent conversions , drew graph 2 about 3128-3683cm^-1α-t curve at 180 volts voltage, dα/dt-t curve in graph 3, curve fit in graph 4. From the graph 2,3,4, we may see that as the time going on, the solidification speed slow down. We also compare the changes of the amino baking finish in graph 5 at different voltage. We have analyzed that how different voltage can affect the amino baking finish's solidification speed. We have got that the amino baking finish will have the most fast solidification speed when the quartz lamb' voltage is 180 volts. The part two: the amino baking finish's curing reaction dynamics research:The solidification dynamics research, in the system interior reaction mechanism field, has very important significance. In the present stage, people mainly use the thermal analysis method to study the system solidification dynamics, and to compute solidification dynamics parameter. But in this paper, we have used the infrared spectrometry, the origin software mapping, and the curve fitting methods to study solidification dynamics of amino baking finish at 3128-3683cm^-1 spectrum band under the infrared irradiation, have obtained the solidification dynamics parameter, opened one new method for the solidification dynamics research.The solidification dynamics equation is dα/dt= kf(α) , f(α) issolidification model function. About the complex solidification system, at the present stage, the experiences models are used widely: the n-level response model and the self-catalyzed model. The self-catalyzed model is a reaction that the catalyst is a kind of reactants of the reaction. As a result of the catalyst is one of the resultants, at the beginning of the reaction, there is no catalyst or the catalyst is very few, the reaction speed is low. Along with the reaction carrying on, the reaction speed curve has a maximum value, after the reaction having gone on for a long time, the reactants reduced, the reaction speed reduced, and the reaction kinetics curve assumes S, it's the typical form of the self-catalyzed reaction. And about the self-catalyzed model, we commonly used the equation as follows that proposed by Kamal and other people: But the n-level reaction model, here n Express that the reaction speed is how deeply depended on the reactants concentration. If the n value is much bigger, the reaction depends more heavily on the reactants concentration. About the n-level reaction kinetics, we commonly use the equation as follows:We can judge that the reaction carried on by what dynamics process through the speed-time curve, if there is a peak value or not.The graph 4 is the solidification speed curve at 180 volts voltage, from the graph we can see, along with the time going on, the solidification speed slowly reduced, no maximum value appeared, and we can judge that the solidification is not self-catalyzed process, it is according on the n-level reaction kinetics to carry on. We can use the n-level reaction kinetics equation (2) to calculate the parameters, we take the logarithm to the formula (2) at both sides.We use ln (dα/dt) as the ordinate axis, the ln(1 -α) as the abscissa axis, plot a graph with disperse spots, make linear fitting, calculate the dynamics parameters n, k. it shows in the graph 6. Using the method showed in the graph 6, we have calculated the reaction order and reaction speed constant, it shows in the table 1.