Selection and application of dispersants in water-based wood coatings.

0 Foreword . The hydration of wood coatings has been developed well in recent years under the situation of environmental protection drive and policy pressure. In order to make consumers satisfied with the coating effect, water-based wood coating can not be separated from a variety of water-based additives to help. Among them, water-based white paint for water-based coatings, because it can decorate a variety of different appearance is not very beautiful substrates such as density plate, melamine plate, rubber wood, etc., but also the deployment of a variety of brilliant colors, by the public's love, in the water-based wood coating market accounted for a large share, in order to make it better For consumer services, still need to deal with the following problems: (1) poor resistance to contamination, mainly tea resistance, coffee resistance has a clear imprint;these problems in addition to being affected by emulsions, dispersants play an important role. The selection of suitable dispersants can improve the coloring power of pigments, improve storage stability and maintain color uniformity. Therefore, in order to solve the above two problems, the author selected 3 systems, for different manufacturers of 10 kinds of dispersants, including stain resistance, color after finger study color difference, white paint storage after the fineness of the viscosity changes, etc. were tested and evaluated, to arrive at different performance requirements of the coating film needs to choose the dispersant.1 Experimental part 1.1 Main raw materials and equipment gold-redstone titanium white powder, industrial grade; acrylic emulsion, acrylic modified polyurethane dispersion, Opaldi, DSM; desiccant, humidifier, Bick chemistry; rheumor additives, thickeners, Bik Chemical, German Mingling Chemical; Dispersants, Bick Chemical, Digo, Vibos materials.Electronic Balance, ME3002E, ME3002E, METLER-Tolido Instruments (Shanghai) Co., Ltd.; Stomer viscosity meter, BROOKFIELD KU-2; fine plate: scraper micrometer with a range of 100 m, Shanghai Modern Environmental Engineering Technology Co., Ltd.; chromameter, X-Rite® SP62-162, Aiser.
1.2 paint preparation . A, B, C3 kinds of varnish and 10 kinds of different dispersants of white slurry, and then the varnish and white paste according to 70:30 (quality ratio) dispersion into different white paint. Among them, the A and B systems are acrylic emulsion systems and C systems are acrylic modified polyurethane emulsion systems. The 10 dispersants are D190, X, D192, D194N, D199, D2010, BYK-LPN 23144, Y, 4060, 4090. See tables 1 and 2 for specific programmes.. Note: The amount of dispersant added is the active ingredient/titanium white powder of dispersant.1.3 Test MethodStain resistance test: Due to the limited size of the plate, 5 kitchen reagents were selected for testing, coffee 24 h, green tea 24 h, alcohol 24 h, vinegar 24 h, mustard 1 h.refers to the research test: with a wire rod of 100 m to scrape the coating film and black and white paper jam, when the coating film is half-dry, with your fingers on the surface of the white paper jam film grinding clockwise to increase the viscosity, close to fast grinding, after placing the drying, 50 degrees C oven baking 1 h, test the color difference between the grinding area and the unbrating area.: Test with reference to QB 8002-2000 method.viscosity test: Test the viscosity value of the sample with a Stommer viscosity meter.2 Test Results 2.1 Effects of Dispersants on Stain ResistanceThe Effects of Dispersants on Stain Resistance of Acrylic Emulsion A System Can be found in Table 3. As can be seen from Table 3, the effects of dispersants on mustard and alcohol resistance are not very different, for coffee, green tea, vinegar, BYK-LP N 23144 is the best, followed by X, D192, the worst 4090, D194N.the results of the test results on the contamination resistance of the dispersant to the acrylic emulsion B system can be found in Table 4. As can be seen from Table 4, the effects of dispersants on mustard and alcohol resistance are not very different, for coffee, green tea, vinegar, BYK-LP N 23144 is the best, followed by X, D192 vinegar resistance is not very good, the worst for 4090, D194N.the results of the test results on the contamination resistance of the dispersant to the acrylic modified polyurethane C system can be found in Table 5. As can be seen from Table 5, the effects of dispersants on mustard and alcohol resistance are not very different, for coffee, green tea, vinegar, BYK-LP N 23144 is the best, followed by X,integrated test results of the three systems, for the test results of contamination resistance consistent, the best stain resistance dispersants for BYK-LP N23144, followed by X, the worst for 4090, D194. The quality of coating film resistance is mainly related to the denseness of the coating film, for BYKLPN 23144 and X, the denseness of the coating film is higher, for tea and coffee can have a good barrier between the canine and caffeine, can not penetrate into the coating film.2.2 refers to the study the adjustment of a light gray into each of the three systems. The effect of dispersants on acrylic emulsion A system is shown in Figure 1. For the A system, the color difference is generally larger. The dispersants used with the smallest chromic difference were 4090 and D190 at 0.78 and 0.87, respectively, while the largest color differences were D199 and 4060 at 3.52 and 3.51, respectively. the effects of the dispersant on the acrylic emulsion B system are shown in Figure 2. For the B system, it refers to the study of chromat difference individual differences, the maximum color difference and the minimum color difference span is large. The dispersants used with the smallest color difference were 4090, Y and X, which were 0.39, 0.43 and 0.55, respectively, and the largest color difference was D194N and 4060, which were 2.38 and 1.96, respectively. the effect of the finger-study chroma on the acrylic emulsion B system of the dispersant is shown in Figure 3. For the C system, the color difference is generally smaller than the other two systems. The dispersants used to study the smallest chroma are D2010, BYK-LP N 23144, and the largest color differences are D194N, Y and X. of the three systems, the role of different dispersants is not consistent between different systems. The main reason for this result is that there are different synergies between the color paste and different dispersants and different emulsions, specifically, there is a problem of compatibness, so the stability effect on the color paste in the system will be different. Therefore, in practical application, for the color adjustment requirements of higher products, or should be specific to different systems to screen dispersants. 2.3 fineness test A system uses different dispersants after dispersion of 2 d, half a month, 1 month of different time on the effect of fineness can be seen in Figure 4. As can be seen from Figure 4, there will be curve fluctuations over time, but not much. The fineness of D194N, D190, and X is relatively small, at about 20 m. . The effect of different dispersants on fineness at different times of 2 d, half a month and 1 month after dispersion of the B system is shown in Figure 5. As can be seen from Figure 5, with the change of time, most of the changes in the fineness of the oil will have curve fluctuations, basically showing an increasing trend. The fineness of D190 and X is relatively small and stable, and byK-LP N 23144 changes the most, increasing from 25 sm to 50 sm, 4060 and D194N. . The effect of different dispersants on fineness at different times of 2 d, half a month and 1 month after dispersion of the C system is shown in Figure 6. As can be seen from Figure 6, most of the changes in the fineness of the oil over time will have curve fluctuations, but not much. The fineness of D2010, D194N, D190, X, and D199 is relatively small and stable, around 20 m, but for D192 it changes a lot, from 15 sm to 55 sm, and from 50 m to 65 m. , the effects of these dispersants on fineness are also more consistent in these three systems, with the smallest dispersants used being D190, X, and D194N. 2.4 viscosity test track changes in the Stommer viscosity meter for sample paints with different dispersants in three systems. The effect of different dispersants on viscosity at different times after dispersion of 1 d, 2 d, half month and 1 month is shown in Figure 7.
As can be seen from Figure 7, the effect of different dispersants on the viscosity size of the A system is not the same, of which D190, 4090, X viscosity is relatively large, several other viscosity is smaller; . The effect of different dispersants on viscosity at different times after dispersion of 1 d, 2 d, half month and 1 month is shown in Figure 8. As can be seen from Figure 8, the influence of different dispersants on the viscosity size of B system is not as large as that of A system, of which X, 4090 viscosity is larger; . The effects of different dispersants on viscosity at different times of 1 d, 2 d, half month and 1 month after dispersion of the C system are shown in Figure 9. As can be seen from Figure 9, the influence of different dispersants on the viscosity size of the C system is not as large as that of the A system, of which the viscosity of 4090 is larger, and for the C system, the viscosity is stable over time. To sum up, for the three systems, the 10 dispersants used did not have a post-thickening effect on the sample paint. . 3 Conclusion (1) Dispersants on white paint system resistance to tea, coffee and other chemical resistance has a very important impact, dispersants in these three systems of the impact of the trend is consistent, the best performance of BYK-LP N23144, X, for cabinets, dining tables, these chemical resistance requirements of furniture coatings can use this class of dispersants. (2) For the study of chromance, different systems, the results are very different, or even the opposite. In these systems, the better performance is: A system: 4090, D190, B system: 4090, Y, X, C system: D2010, BYK-LP N23144, D190. Therefore, the color adjustment requirements are high, these three systems may consider the use of these dispersants. But other systems still need to be re-screened. (3) dispersants on fineness are also more consistent in these three systems, the smallest of which is mainly D190, X, D194N. (4) dispersant on the viscosity of the white paint system, in all three systems there is no post-thickening phenomenon. .