Research on the synthesis and application of N, N, N', N'iv (2-hydroxypropyl) hexydimide

Abstract
This paper uses hexachloride and diopropanolamine as the main raw materials to synthesize N, N, N'-four (2-hydroxypropyl) hexylamide curing agent, with the help of liquid phase, infrared spectroscopy to the product. The application properties of N, N, N', N'-four (2-hydroxypropyl) hexydimide as curing agent products and commercially available EMS-1260, HAA, TGIC products in yellowing, low temperature curing, aging and so on were compared.
1 Introduction
Powder coatings are widely used in the automotive industry, household appliances industry and general industrial fields, with solvent-free, pollution-free, energy saving, reduce labor intensity advantages .
β-hydroxyamine curing agent is a new curing agent developed in recent years, which plays a very important role in the research and application of polyester powder coating. Among them, N, N, N', N'iv (β-hydroxyethyl) hexydimide (HAA) is excellently represented and widely used.
However, due to the high activity and self-structure of HAA products, resulting in the curing of the film after the light loss and surface pinholes are not satisfactory, in response to these problems, the subsequent introduction of new curing agent N, N, N', N'-IV (2 hydroxypropyl) diamide, to a certain extent improved the curing agent HAA above defects, and in the European market has received more and more attention.
Because there is less research on this product in China, this paper mainly explores the synthesis and application of N, N,N', N'iv (2-hydroxypropyl) hexylamide in order to promote the application and development of hydroxynaminide products.
2 Experimental part
2.1 reagents
hethyldiethylene, potassium hydroxide, sodium methanol, sodium ethanol, polyester resin, leveling agent (HL988), sabbath (HA501), titanium white powder are all industrial products;
2.2 N, N,N', N'-iv (2-hydroxypropyl) hexydimide synthesis
in 500mL four-mouth bottles installed stirring, thermometers and drip funnels and distillation Device, etc., to the reaction bottle to add the formula amount of isopropyl alcoholamine and catalyst, slowly heat the reaction mixture to 150 degrees C, vacuum 0.090MPa, slowly add methamphetamine, control drip time of 1-2 hours. After the drip is added, it takes approximately 6-10 hours to complete the reaction. After the reaction continues to stir to cool down, then the appropriate amount of acetone and other solvents for cold freezing crystals, to obtain a white powdered solid, for N, N, N', N'-four (2-hydroxypropyl) hexydimide products.
2.3 Testing and Symptoms
Hydroxymetric determination with the help of Shanghai Semen ZDJ-4A automatic potion titration meter, Beijing Tektronix XT-4 dual-eye micro-melting point analyzer to determine the melting range of the product, red appearance of the product with the help of the Nicolet 380 Fourier Transform Infrared Spectrometer (IR), and LC-20A Island Zin liquid chromatography test product purity.
2.4 Coating preparation and coating performance testing
C laboratory homemade N, N, N', N'iv (2-hydroxypropyl) hexydimide (or EMS-1260) in accordance with the high-gloss powder coating formula (Table 1), HAA and TGIC in accordance with their own high-gloss generic formula.
the following criteria:
impact test: according to GB/T1732-1993 methods;
Aging Test: Methods specified by ASTM G-154;
100-grid tests: Methods specified in accordance with ASTM D-3359;
leveling ratings: leveling ratings based on the U.S. PCI's leveling effect rating standard board;
Gloss Test: Methods based on ASTM D-523.
3 Results and Discussion
3.1 Purity Determination
In the experiment, we measured the melting range and hydroxyl value respectively with the help of melting point meter and automatic potion meter, the melting range of the product is: 100 to 103 degrees C, the hydroxy value is 585mgKOH/g, very close to the theoretical value, indicating that the purity of the product is high.
can also be seen from Figure 1, through the determination of liquid chromatography of the product, product purity of more than 98%. Under the same testing conditions, the retention time with the standard peak is around 3.04min. Therefore, it is learned that the products synthesized in this experiment are high purity N, N, N', N', -four (2-hydroxypropyl) hexylamide.
3.2 Infrared spectral symptoms
F diagram 2 is an infrared spectral map of experimental products N, N, N', N'-IV (2-hydroxypropyl) hexydimide, from which it can be seen that 3440cm -1 is the characteristic absorption peak of alamide and hydroxyl, 2920cm-1 absorption peak is the characteristic absorption peak of methyl and medehyl, and 1630cm-1 is the characteristic absorption peak of niobium in alamide.
3.3 Application comparison in high-gloss powder coatings
We studied EMS-1260, laboratory-made N, N,N', N'-IV (2-hydroxypropyl) hexylamide and commercially available HAA products in high-gloss powder coating effects, the results can be seen in Table 2.
From the surface effect of table 2 model, N, N, N, N'-four (hydroxypropyl) hexylamide leveling effect is slightly better than the current commonly used hydroxyalineamide curing agent HAA products, the thickness of pinholes appear on the surface also has a certain increase, with EMS-126 0 product performance is basically the same, which shows that N, N, N', N'-four (2-hydroxypropyl) hexydimide structure changes, increase the reaction level resistance, reduce curing activity and curing speed, extend the leveling time of the coating, is conducive to gas emissions, the thickness of the coating pinhole will be increased accordingly.
3.4 Yellow Trend Analysis
3.4.1 vs. Yellow Change Trends of Serotonamide Products
Standard L: 97.56 a:-1 with cured yellowing of EMS-1260 model 180 degrees C 1.30 b:0.51, respectively, studied EMS-1260, laboratory homemade N, N, N', N'-IV (2-hydroxypropyl) hexylamide and commercially available HAA products cured after the yellowing trend of the film, the results can be seen in Table 3.
the yellowing effect of N, N,N', N'-four (2-hydroxypropyl) hexylamide in terms of the effect of the SAMPLE EMS-1260, as can be seen from Table 3 at different temperatures (180 degrees C, 200 degrees C and 220 degrees C) b The change trend of the value, from the yellow change effect, compared with the other two samples, HAA products at different temperatures are obviously worse, yellow change is more serious, and EMS-1260 and laboratory synthesis of N, N, N', N'-iv (2-hydroxypropyl) hexylamide yellow change is relatively close.
3.4.2 vs. TGIC's yellowing trends
In outdoor weather-resistant powder coatings, researchers are generally accustomed to yellowing other curing agent products with TGIC products, so N, N, N'N', N'S4 (2. hydroxyl) hexydimide products and TGIC products for yellowing trends, the results are seen in Table 4.
table 4 shows that we take the curing yellowing of our respective curing agent products at 180 degrees C as the standard, and carry out different curing agent varieties and yellowing trends at different temperatures, the results show that the same formula at 180 degrees C baking curing, in terms of the color difference of the model, TGIC and HAA are closer, N, N, N', N'-four (2-hydroxypropyl) hexylamide color performance is a little greener. In terms of different temperature change trends, TGIC performance is more stable, HAA yellow change increased significantly, laboratory synthesis of N, N, N',, N'-iv (2-hydroxypropyl) hexylamide in both the color difference of the model and temperature changes on the effect of yellow change are excellent.
considering the wide range of curing temperature of TGIC and HAA products, different curing temperatures also differ in the yellowing of the coating film, we also study the different curing temperatures (150 degrees C/25min, 160 degrees C/ At 15min, 160C/20min, 170C/15min, 180C/15min), the changes in the yellowing b values of different curing agent powders are shown in Figure 3.
can be seen from Figure 3, different curing temperature and curing time have some effect on the yellow change b value of the coating film. From 150 degrees C as the starting curing temperature, from the analysis of the yellowing trend of the coating film, the coating film of the HAA system is poor at different temperatures, yellowing is obvious, while N, N, N', N'-four (2-hydroxypropyl) hexylamide has obvious anti-yellowing advantages below 200 degrees C, compared with TGIC, there is no significant change in color difference b value, anti-yellowing performance is even slightly better than TIC.
3.5 Low temperature curing temperature analysis
We also studied the laboratory homemade N, N, N', N'-four (2-hydroxypropyl) hexylamide, commercially available HAA products and TGIC in low temperature curing powder coating application effects, the results can be seen in Table 5.
From table 5, the contrast effect of low temperature curing of these three curing agents can be seen, compared with TGIC, N, N, N', N'-iv (2-hydroxypropyl) hexylamide and HAA can be achieved at lower temperature film curing, such as 150 degrees C can achieve full curing, basically in the indoor powder coating low temperature curing temperature range can achieve outdoor powder curing, energy consumption can be significantly reduced.
3.6 Aging test
We studied the aging test of different curing agent models at 1500h under the same conditions, and the results are in Table 6.
From table 6 aging test results, the aging effect of the three models is not very different, color difference, loss of light, powdering and bubble changes in 1500 hours basically on the same level, indicating that N, N, N'four (2-hydroxypropyl) hexylamide and HAA, TGIC, aging resistance can meet the requirements of outdoor powder coatings.
4 Conclusion
The main raw material synthesis using hexydioxymethylate and diopropropylamine was obtained N, N,N', N'iv (2-hydroxypropyl) hexydamide, and the results of the symptoms of liquid phase and infrared spectroscopy showed that high purity products were obtained. Comparing the application performance of N, N, N', N'-four (2-hydroxypropyl) hexydimide as a curing agent and commercially available EMS-1260, HAA, TGIC products in yellowing, low temperature curing, aging, etc., the results show that synthesis obtains N, N, N,N, N'-four (2-hydroxypropyl) hexydamide in performance and EMS-1260 almost consistent, in thick applied pinholes, yellowing resistance and other aspects significantly better than the commercial HAA products, in low temperature curing better than TGIC, in terms of aging resistance and HAA, TGIC is almost the same.
Tang Zengrong
1, 2
, Hong Xiaoping
1, 2
, Yang Zhiping
1, 2
, Wang Yongyi
1, 2, 3
1. Huangshan Huahui Technology Co., Ltd. Postdoctoral Workstation
2. Anhui Province Powder Coating Additive Engineering and Technology Research Center
3. Huangshan College School of Chemistry and