Medium Density Fiberboard Electrostatic Powder Coating Process

The preheating method is used to enhancing the electricity conductivity of medium density fiberboard,as to resolving one difficult problem of MDF electrostatic powder coating, based on the special internal structure and surface performance of MDF and the metal-material powder coating technology. The achievement of lower temperature curing technology(130℃,6min)of the film on MDF By the utility of infrared-convective technology. A process route of MDF Electrostatic Powder Coating suited the situation of our country is exploited, which offered a new environmental,economy and efficiency method for the MDF surface decoration, especial for the furniture painting. The influence of different methods of surface treatment and pretreatment on the performance of film and their cause were analyzed. The relation between first-pass transfer efficiency and the consistency of thickness of the film on the test sample of wood-based material and the preferences of process is studied. The influence of melt temperature, curing temperature and total time on the performance of film was investigated. The main conclusions and innovations and innovations are as follows:1 The influence of sanding and painting of priming on the adhesion of film and its causes were analyzed based on the theory of interface. The best method of surface treatment is confirmed, which is sanding four sides of test sample with 180# sandpaper firstly, and then putty filling four sides of test sample , sanding all surface of sample with 180#, 240# and 320# sandpaper in turn at last.2 The preheating treatment was confirmed to been the best pretreatment methods, according to the comparation among the preheat treatment, painting conducting solution and the combination of two aboved, and the analyzing to 3 indexes of coating quality, thickness of ratio of different part and gloss.3 The best preferences of process were determined by analysis of variance based on the result of orthogonal, spraying distance is 150mm, air pressure is 0.05Mpa; electrostatic voltage is 60kV, and the once transfer efficiency is above 30%. The process methods of improved first-pass transfer efficiency was achieved, which is decreasing the spray distance as short as possible, increasing the electrostatic voltage properly under the permissibility of equipment.4 The curing condition of melting temperature at 160℃, curing temperature at 130℃～160℃, total time at 6min～3min, which hardly damage the performance of medium-density fiberboard, was gained by the orthogonal experiment, based on the conduction of thermal and the conductivity of wood and the application range of powder painting with low curing temperatures. And the inspection results of evaluating the performance achieve or exceed the request of interrelated country stardard.5 The proper film thickness with 160μm～180μm and its performance was concluded according to the test result, Which is gloss:24.01, grade 2. adhensive: grade 2. wearability: grade 3.resistance to liquids: grade 2. resistance to wet heat: grade 2. resistance to dry heat: grade 1. surface performance: a little wrinkle on the surface of film.