Abstract:This paper uses hydroxyacrylic acid dispersion and amino resin as the main reactants to prepare a water-based amino baking paint, and studies the use of dipropylene glycol butyl ether (DPnB), ethylene glycol butyl ether Effects of six film-forming additives: ether (BCS), diethylene glycol butyl ether (DGBE), propylene glycol methyl ether (PM), propylene glycol methyl ether acetate (PMA), and isopropyl alcohol (IPA) on the performance of water-based amino baking paint . By characterizing the dynamic and static rheology of the samples and testing the particle size, the mechanism of action of each film-forming additive was studied. The results show that PM has good compatibility with both amino resin and hydroxypropyl dispersion resin. It acts between the water phase and the dispersion particles, which is beneficial to the stability of the dispersion system before film formation. When PM is used as a film-forming additive, the paint film has a faster surface drying speed and shows better mechanical properties after drying. After baking at 130°C for 25 minutes, the 60° gloss of the paint film reached 89.5, the flexibility reached 1 mm, the forward impact was 50 cm, the backlash was 50 cm, and the pencil hardness was H, indicating that PM is the key to the amino baking paint system in this study. Best film-forming additive.
Keywords:Film-forming additive; water-based amino baking paint; rheological properties; water-based hydroxyacrylic dispersion; amino Resin
Background introduction
The current global environmental problems are becoming increasingly serious. Solvent-based coatings have been difficult to meet people's environmental protection requirements. As an alternative, water-based coatings have attracted more and more attention and research from scholars because of their low VOC, odorless, green and environmentally friendly advantages. The green environmentally friendly paint water-based acrylic amino baking paint is prepared by using amino resin and water-based acrylic resin as film-forming substances, compounded with additives, pigments and fillers. It has high gloss, high hardness, excellent media resistance, and good gloss retention. Due to its advantages, it has become one of the most widely used and popular industrial coatings, playing a role in metal decoration and protection in home appliances, automobiles, medical equipment and other industries. Hydroxyacrylic acidrgin: 0px; padding: 0px; border: 0px; list-style: none;">-1 The broad peak at -1 is the stretching vibration peak of -OH. On the spectrum line of amino baking paint, 1 600 cm -1 The bending vibration peak of -NH appears, which is the curing of hydroxypropyl dispersion and amino resin Produced later. At the same time, due to the ether exchange reaction between hydroxypropyl dispersion and amino resin, 1 170 cm in the amino baking paint spectrum -1 The characteristic peak of ether bond appeared, indicating that the water-based amino baking paint was successfully prepared.
2.6 Effects of different film-forming additives on the basic properties of paint films
The test results of the effects of different film-forming additives on the gloss, hardness, adhesion, impact resistance, flexibility, etc. of the amino baking paint film before and after 7 days of thermal storage are shown in Table 5 Show.
Table 5 Corresponding paint film properties of different film-forming additives before and after 7 days of thermal storage
As can be seen from Table 5, the 60° gloss of the paint film corresponding to different film-forming additives before heat storage is slightly different than BCS. Low outside, the other 5 types are not much different. The pencil hardness of the six groups of samples can all reach H, the adhesion is level 1, and the flexibility is 1 mm. However, the impact resistance is different. The paint film using DPnB, PMA, and PM as film-forming additives has the best impact resistance. Both forward and backflush pass through 50 cm, and the impact resistance of the paint film using BCS, DGBE, and IPA as film-forming additives is slightly worse. After being stored at 50°C for 7 days, the coating with IPA as the film-forming additive had soft precipitates after thermal storage. More insoluble matter precipitated during filtration after stirring, which caused a significant decline in the performance of the paint film. The 60° gloss dropped from 90 . 9 is reduced to 46. 7, adhesion is reduced to level 2, flexibility is reduced to 2 mm, and impact resistance forward and recoil are both less than 10 cm. The paint liquid using PMA as a film-forming additive has been partially gelled after hot storage, and the paint film has lost its use value. When BCS is used as a film-forming additive, due to the precipitation of water during thermal storage, the gloss and impact resistance of the paint film will be reduced to a certain extent after thermal storage. For paint films using DGBE, due to the high boiling point of DGBE and its relatively slow evaporation rate, some film-forming additives may remain in the paint film, resulting in a decrease in the gloss and impact resistance of the paint film after thermal storage.
When the film-forming additives are DPnB and PM, there is almost no change in the performance of the paint film before and after thermal storage, but the properties of the paint corresponding to DPnB The KU viscosity is as high as 96.2, which is not conducive to on-site construction of coatings, while the KU viscosity of PM's corresponding coating is only 48.8, which has higher application value. Therefore, overall, PM is the best film-forming additive for this amino baking paint.
3 .Conclusion
The dispersion was prepared using six film-forming additives: DPnB, BCS, DGBE, PM, PMA, and IPA. Water-based amino baking paint, the results show that PM is the best film-forming additive for this system. The paint film using PM as the film-forming additive can be tack-dried in 40 minutes at a relative humidity of 70%. The paint has not settled after being stored at 50°C for 7 days. After baking at 130°C for 25 minutes, the paint film has a 60° gloss It reaches 89.5, its flexibility reaches 1 mm, its forward and recoil impact resistance reaches 50 cm, and its pencil hardness H, which has certain application value. And through the characterization of static and dynamic rheology and particle size analysis, the mechanism of PM in the amino baking paint system was explained. The results show that PM has strong dissolving power for both amino resin and dispersion resin. It acts between the water phase and the dispersion particles, which is beneficial to improving the stability of the system before the dispersion film is formed.
Cite this article: Rong Jinchuang, Yan Lei, Song Kunlun, Zhong Jiang. Research on the influence of film-forming additives on the performance of water-based amino baking paint [J]. Coatings Industry, 2021, 51(12): 76-82.
3. Conclusion
Dispersion-type water-based amino baking paint was prepared using six film-forming aids: DPnB, BCS, DGBE, PM, PMA, and IPA. The results showed that PM was The best film-forming additive for the system. The paint film using PM as the film-forming additive can be tack-dried in 40 minutes at a relative humidity of 70%. The paint has not settled after being stored at 50°C for 7 days. After baking at 130°C for 25 minutes, the paint film has a 60° gloss It reaches 89.5, its flexibility reaches 1 mm, its forward and recoil impact resistance reaches 50 cm, and its pencil hardness H, which has certain application value. And through the characterization of static and dynamic rheology and particle size analysis, the mechanism of PM in the amino baking paint system was explained. The results show that PM has strong dissolving power for both amino resin and dispersion resin. It acts between the water phase and the dispersion particles, which is beneficial to improving the stability of the system before the dispersion film is formed.
Cite this article: Rong Jinchuang, Yan Lei, Song Kunlun, Zhong Jiang. Research on the influence of film-forming additives on the performance of water-based amino baking paint [J]. Coatings Industry, 2021, 51(12): 76-82.
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