Study on the application performance of low temperature cured powder coating on particle board

Shuai Haokun 1, Qiu Fengli 1, Zhang Wen standard 2, Xiao Haihu 2
(1. Zhejiang Tiansong New Materials Co., Ltd., Zhejiang Lin'an 311300; Zhejiang Agricultural and Forging University, Zhejiang Lin'an 311300)
Summary: Through the DSC differential scanning method, it is concluded that the powder coating curing temperature prepared by polyester resin TS4613 is 145. At 5 degrees C, the film composite performance of the 801 rubber-treated particle board was found to be the best by using the low temperature cured powder coating to apply particle boards that had been treated in different ways. At the same time, the study found that the more powder, the better for powder coating curing transfer printing.
key words: low temperature curing; powder coating; particle board; transfer
doi:10. 13752/j. issn. 1007-2217. 2014. 04. 006
particle board as a wide-ranging artificial board, with broad prospects for development. Like other man-made panels, particle boards have the advantages of saving wood, improving wood performance, using poor materials, and improving the comprehensive utilization rate of wood. With the increasing awareness of environmental protection, the appearance of particle board decoration performance has also put forward higher requirements. Powder coatings have become a trend by applying particleboards with powder coatings because they comply with the "4E" principle. Particle board because of the surface there are various grooves, catheters, tube cells, wood rays, etc. , on the one hand will cause uneven surface, on the other hand, will also cause the flow of powder coating is poor and uneven. Therefore, powder coating the surface of the particle board is much more difficult than operating on metal materials. This experiment studies the application properties of the particle board surface by preparing low temperature curing powder coating, optimizing the powder formulation, sanding, mechanical grinding and chemical treatment on the surface of the particle board.
1. The experimental part1. 1 Main raw materials
low temperature cured polyester resin TS4613: Zhejiang Tiansong New Materials Co., Ltd.; Epoxy E-12: Industrial Products, Huangshan Jinfeng Industrial Co., Ltd.; Sabbath (desmodizer): Ningbo South China Sea Chemical Co., Ltd.; GLP588 (leveling agent) ): Ningbo South China Sea Chemical Co., Ltd.; GLP701 (brightener): Ningbo South China Sea Chemical Co., Ltd.; Particleboard (4cm×8cm): Fujian Fuman Wood Co., Ltd., 120×75×12mm3, water content of 9. 5%~11. 0%;801 glue: Wuhan Xiaguang Decorative Coatings Co., Ltd., the main ingredients are polyethylene alcohol and polyuroid resin; 600 sandpaper: Shanghai sandpaper factory; X8126 milling machine (with grinding plate): homemade; 15% NaOH: homemade; polyvinyl acetate emulsion (white glue): Jiashan Huatao additive factory; paraffin: Guangzhou Corny Chemical Co., Ltd.
1. 2 Preparation of the
the polyester resin TS4613, epoxy resin (E-12), pigments, fillers, leveling agents, degassing agents, curing promoters, etc. by formulation amount (see Table 1) added to the dispout In the material container, fully stirred evenly, after the extruder melt extrusion, crushing, after 180 mesh sieve, that is, to obtain powder coating, its static spray on the model, and then put the model in the infrared curing box to cure the coating film.
Table 1 Powder Coating Formula
1. 3 Instrument
Q2000 type DSC differential thermal analyzer: TA Instrument Corporation of the United States;
2. Results and discussions2. 1 Low temperature cured powder coating system to determine
this experiment through the DSC differential thermal analyzer, with empty sample plate as a guide, nitrogen protection, scanning heating rate of 5, 10, 15, 20 degrees C /min, to determine that the prepared powder coating for low-temperature curing powder coating.
Figure 1 non-iso-temperature curing DSC curve at different heating rates TS4613 powder coating DSC curve
from Figure 1, as can be known from Figure 1, with the increase in heating rate, powder coating curing starting temperature To, peak temperature TP and peak temperature Tf are all moving in the direction of high temperature, with β to, Tp and Tf figure 2 respectively. The extraterrive method β to 0, the gelding temperature of the powder system can be obtained basically, to 95 degrees C, and the curing temperature TP is 145. The temperature of 5 degrees C and the post-curing temperature is Tf to 175 degrees C. It is stated that the powder prepared by TS4613 meets the requirements of low temperature curing.
2 TS4613 powder coating curing temperature-warming rate relationship
2. 2 Surface treatment and coating studies of particle boards
2. 2. 1 Various methods to deal with the test piece powder situation
(1) with 600 x sandpaper, sand direction for portrait, sand light time of 3min, sanding treatment of particle board; (2) with grinding head speed of 150rpm, feed of 36mm/min, spring compression of 0. 5mm, mechanical grinding of the particle board, (3) a small amount of 15% NaOH solution with cotton is evenly applied to the particle board test piece, and then put the test piece into the temperature has reached 180 degrees C Bake in the drying box for about 1 to 2 min, remove and cool for backup; (4) apply a small amount of white glue evenly to the particle board test piece with a brush, and then place the test piece in a drying box with a temperature of 180 degrees C. Bake about 5min, remove and cool for spare; (5) apply paraffin evenly to the particle board test piece, about 1min after applying, put the test piece in an oven at 100C to bake 1min paraffin Melt, then remove the cooling spare; (6) use a brush to take a small amount of 801 glue evenly applied to the particle board test piece, and then put the test piece in a 100 degrees C oven baking 1min, remove the cooling spare. The particle boards treated by the above various methods are electrostectrecturectured with powder coating, and the powder on each test piece is shown in Table 2.
Table 2 Powdering of the test pieces treated by various methods
brush takes a small amount of white glue and applys them evenly to the particle board test piece, then places the test pieces in a drying box with a temperature of 180 degrees C and bakes them for about 5min, removes them and cools them back up; and (5) applyes paraffin evenly to the particleboard test pieces. After applying about 1min, place the test piece in a 100C oven and bake 1min to melt the paraffin, then remove the cooling spare; (6) apply a small amount of 801 glue evenly to the particle board test piece with a brush, then place the test piece in a 100C oven and bake 1min, remove the cooling spare. The particle boards treated by the above various methods are electrostectrecturectured with powder coating, and the powder on each test piece is shown in Table 2.
from the coating film quality, with 801 glue treatment of the particle board coating film comprehensive performance is the best. The 801 film on the surface of the particle board reduces the conductivity between the particle board and the electrostation gun, and its powdering volume is slightly worse than that of mechanical grinding and sanding. Although mechanical grinding and sanding effect is good, but the quality of the coating film is poor, not suitable for use. The particleboard treated with NaOH solution, paraffin and white glue not only has a low powder rate, but also has a poor film quality,
2. 2. 2 Analysis of particle board powder coating film
water resistance test: according to GB/T1733-1993 standard test. The adhesion test of the sing-in method: according to gb/T9286-1998 standard test.
hardness test: according to GB/T6739-2006 standard test.
Table 3 Effect of Surface Treatment on Coating Performance
As can be found in Table 3, a test piece of 15% NaOH solution is applied to the surface of the particle board substrate, and a portion of NaOH, residual hydroxyl and poly The reaction of the ester-based carboxyl causes the whole powder system to have different curing speeds, resulting in rough coating, coupled with the presence of more hydrophory-based groups, resulting in 15% NaOH solution treatment of the test piece after 24h immersion at room temperature, there is a foaming phenomenon, poor water resistance.
From Table 3 can also be seen that all treatment methods are high hardness, of which paraffin-coated test surface hardness is the lowest, which is due to the low surface pressure of wax, in the coating film curing process, wax will migrate to the coating surface, resulting in soft coating film, reduced hardness.
From the paint film quality point of view: coating pinholes of 801 glue is very few, surface quality is significantly better than other treatment methods, this is because the particle board surface is an uneven plane, rotary cutting, there are various types of cells such as catheters, large capillary tubes, fibers are separated to form uneven bumps, 801 glue will be filled into these gaps, will be closed, so that the powder coating in the solidification has a good smoothness, so good smoothness.
2. 2. 3 Sample electronic scanning electron mirror observation
Figure 3 scanning electron micrograph
visible from Figure 3, the surface of the unprocessed test piece has a great gap, and uneven bumps. Other treatments have closed part of the void to some extent, and the surface is significantly smoother than the unprocessed one. In terms of clearance, 801 glue treatment< sand treatment< grinding treatment< paraffin treatment < not treated. Therefore, the surface flatness of applying 801 glue is the best.
effect of the amount of powder on the coating film on the printing effect of the testThe particle board is coated with 801 glue film, dried, then powdered, after a certain period of pre-curing, it is transferred and printed. The effect of the amount of powder applied on the coating on the transfer of the printing is shown in Table 4.
Table 4 on the impact of powder on the transfer of printing
From Table 4, it can be known that the test piece with more powder is generally printed after the pattern is clearer, the overall effect of the printing is good probability is high;
4. Conclusions(1) The curing temperature of TS4613 is calculated by the DSC differential scanning volume heat method. At 5 degrees C, the curing temperature is much lower than that of the polyester-epoxy common type 180 degrees C, and the powder coating prepared by TS4613 can be determined to be a low temperature curing powder coating.
(2) Through the study of different treatment methods of particle board, it is found that the particle board after 801 glue treatment has the lowest clearance and the best comprehensive performance of surface coating.
(3) through the 801 glue treatment of particle board transfer printing research, found that the amount of powder on the effect of transfer printing has a great impact, the amount of powder, the better the effect of printing.
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