The development of a new low VOC temperature cured fluorocarbon coating

the development of a new low VOC astration fluorocarbon coatingPan Yunfei, Zhang Rui, Zhou Rudong, Zhu Xiaofeng CNOOC Changzhou Coatings and Chemical Research Institute Co., Ltd., Changzhou, Jiangsu 213016IntroductionCoating Raw Materials and Equipment Network:
fluorocarbon coatings have excellent weather resistance, corrosion resistance, chemical resistance and anti-fouling self-cleaning properties, is widely used in construction, vehicles, bridges, ships, chemical anti-corrosion and other fields. However, ordinary fluorocarbon coating contains a large number of VOC (volatile organic compounds), in the process of use is volatile into the atmosphere, not only resulting in waste of resources, but also pollution of the environment, seriously affecting people's health. The VOC content of water-based fluorocarbon coatings is low, but its application in the field of industrial coatings is very limited due to the influence of synthetic technology, performance and other factors. Powder fluorocarbon coating in the production and coating process without VOC emissions, in line with environmental requirements, but its construction process requires special equipment, must be high temperature drying, not suitable for large-scale structural parts of the coating. High solid fluorocarbon coatings can be used for the coating of large and complex structural parts indoors and outdoors, with high tolerance for environmental temperature and humidity, and become a widely popular green industrial anti-corrosion coating. In this study, a new high-performance fluoropropylene vinyl ether (FPVE) fluorine resin with higher fluorine content and solid content, which tends to be strictly alternating, was used as a curing agent for the system, supplemented by a suitable pigment. Materials, solvents, additives, etc., developed a new low VOC astration cured fluorocarbon coating, focusing on different curing agents, dispersants, leveling agents and other effects on the performance of the coating, with a view to achieving high-performance fluorocarbon coating production and coating process of greening and cleaning.1 Test Part 1.1 Raw MaterialsFluorine Resin C-100, Honeywell Corporation; Fluorine Resin A, Domestic; Fluorinated B, Imported; Fluorine Resin C, Imported; N75, N 3390, Z4470, Cosmos; Titanium White Powder R-960, Como Inc.; Carbon Black PRINTEXU, Gas Phase Silica A-200, DeGusse Inc.; Dispersants A, Dispersant D, Bick Corporation; Dispersant B, Efkona Corporation; Dispersant C, Evka Corporation; Level agent BYK-358, BYK-306, BYK-333, Bi Ke Company; leveling agent AFCONA-3777, Evcona Corporation; desiccant AFCONA-2722, Evcona Corporation; Doodle, Beijing Chemical Plant III; Mixed solvents, homemade.1.2 Instruments LE4002E Electronic Balance, Meitler Tolido, Inc.; WSM-250/T Micro Sander, GFJ-1100/U High-Speed Dispersion Machine, Shanghai Saijie Chemical Equipment Co., Ltd. ;D HG-9146A blow drying box, Shanghai Jinghong Experimental Equipment Co., Ltd.; Qnix-4500 thickness meter, Nix, Germany; BYK4563 gloss Miriam, Bicker, Germany; QXD scraper micrometric, QGS drying time meter, QHQ type hand-shake pencil hardness meter, gridr, impactor, flexibility tester, Changzhou Weiye coating machinery factory; Posi Test AT-A pull-out adhesion tester, Deeves High Company, USA; GDS high-temperature wet heat test case, Beijing Zhongke Ring Test Instrument Co., Ltd.; Q-FOG salt spray tester, QUV accelerated aging tester, Q-Lab Company of the United States.formula for 1.3 fluorocarbon coatings reference formulations for fluorocarbon coatings are found in Table 1.1.4 Fluorocarbon coating preparation process A component preparation: according to the formula shown in Table 1, in order to add fluorine resin C-100, dispersants, leveling agents, defoulants, dryers and some mixed solvents, stirring 10-15min at a speed of 300-800r/min; Slowly add titanium dioxide, carbon black and gas phase silicon dioxide, after the feeding at the rate of 300-800r/min stirring 20-30min, and then the sanding dispersed to a fineness of ≤30 m; Preparation of part B: According to the formula shown in Table 1, in the reaction bottle in turn added N3390, Z4470 and mixed solvents, at the speed of 800-1200r/min stirred 20-30min, with 120 mesh copper mesh filtering, packaging, spare.1.5 model preparation and performance test 1.5.1 model preparation single coating model preparationusing a specification of 150mm×70mm × (0.2-0.3) mm of horse port iron plate as a substrate, before spraying with 400 pieces of sand paper polishing treatment, and then wipe clean with acetone. After mixing the A part well, the B part is painted according to the ratio of mass ratio of 10:1.5, the thinner is adjusted to the appropriate spray viscosity, after 10-15min is cooked, the air spraying legal board is used. Preparation of supporting coating model: the thickness of 3-4mm steel plate as a substrate, after oil blasting treatment, roughness of 40-75 m, clean up. Air spraying method in turn sprayed epoxy zinc-rich primer 60-75 m, epoxy cloud iron intermediate paint 100-120 m, homemade fluorocarbon coating 60-80 m, will be made model under standard conditions after maintenance 7d, sealing treatment.1.5.2 performance testtest method can be found in Table 2.2 results and discussion2.1 coating performance fluorocarbon coating and its supporting coating system of the main performance can be seen in Tables 3 and 4 respectively.2.2 Fluorine Resin SelectionCurrently commercially available at room temperature cured fluorine resins are mainly FEVE fluorine resins, which are co-polymers of fluoroolefin monomers (TEFCs or Teflons) and vinyl monomers (vinyl ether monomers or vinyl monomers or their mixed monomers). C-100 is a new high-performance FPVE fluorine resin, which has higher fluorine content and solid content, and tends to strictly alternate co-cluster. The typical physical parameters of C-100 and several astrated fluorine resins are compared to Table 5. 5 it can be known that, compared with several fluorine resins on the market, the C-100 has higher solid content and lower viscosity, higher solid hydroxy value, higher fluorine content, theoretical analysis, C-100 is more suitable for the preparation of high-performance, high solid content, low VOC fluorocarbon coatings. 2.3 Curing agent selection Due to special requirements such as high weather resistance for outdoor use, curing agents can only choose in the long-term exposure to the harsh conditions of the sun and rain will not yellow, weather resistance is particularly prominent fat or lipid ring isocyanate compounds. Commonly used are HDI (hexamethyl diocyanate) diozone, HDI trimer, IPDI (isofone diocyanate) trimer and so on. The structure and composition of various curing agents are different, and the effects on the properties of fluorocarbon coatings are different. The curing properties of curing agents such as N75, N3390 and Z4470 and C-100 were examined in the experiment, and the results were shown in Table 6. by Table 6, it can be known that the use of curing agent N3390 fluorocarbon coating performance is relatively good, but the use of N3390 alone also has shortcomings, that is, the coating application period is short, the paint film is soft. Theoretical analysis, in the N3390 part of the Z4470 can be more obviously shorten the coating non-stained time, extend the application period of the coating, while the coating hardness and weather resistance will have a certain degree of improvement and improvement. In the experiment, N3390 and Z4470 were re-matched as curing agents of fluorine resin C-100, and the effect of the different mass ratios of N3390 and Z4470 on the performance of the paint film was examined, and the results were shown in Table 7. As can be known from Table 7, when N3390 and Z4470 are combined with a mass ratio of 9:1 as the curing agent of the system, the comprehensive performance of the paint film is better. 2.4 dispersants on coating performance The wetting and dispersion of pigments in resin substations is an important process in coating preparation and has an important impact on coating performance. The addition of wetting dispersants in the grinding stage can shorten the grinding time, reduce energy consumption, improve the storage stability of the coating, prevent the film floating flowering, improve construction performance and so on. Because the atomic radius of fluorine atoms is small, the electro-negative is large, the molecule has a strong chemical inertness, these factors determine that the fluorocarbon resin on the pigment wetting is poor, easy to produce flocculation phenomenon, which causes the paint floating color, flowering, re-coarse and other defects. The problem of poor wetting and dispersion of fluorocarbon resin can be solved by selecting high-performance dispersants. Under the reference formula, the control dispersant addition amount was 6% of the pigment filler, and the effect of 4 different dispersants on coating performance was examined, and the results were shown in Table 8. dispersant A is a co-polymer solution with acidic group, its strong acidic group has a strong anchor cooperation for pigments, at first the coating grinding efficiency is higher, but because of its relative molecular mass is small, late Insufficient contribution to the dispersion stability of the coating, resulting in the coating in accelerated storage of hard bottom, or even back thickening, dispersant D is a pigment affinity group with high relative molecular mass inlay co-polymer solution, its dispersion effect on the coating It is available, but after accelerated storage the coating is obviously layered and hard-sinking, the dispersants B and C are modified polyurethane polymer dispersants, table 8 shows that the wetting dispersion of fluorocarbon coatings is better, and the dispersant Compared with B, dispersant C has more anchoring group and higher relative molecular mass, which plays a good role in anchoring and spatial resistance in the dispersion process of fluorocarbon coating, and the fluorocarbon coating has no floating flowering phenomenon, and accelerates storage stability. 2.5 leveling agent on paint performance During or after coating construction, surface defects are often caused: such as poor substrate wetting, shrink holes, Benaud vortex, etc., these defects are caused by differences in surface pressure of the various raw materials contained in the coating system. These problems can be solved by adding a suitable leveling agent. Under the reference formula, the amount of control leveling agent added was 0.1% of the total quality of raw material, and the effects of leveling agent BYK-358, BYK-306, BYK-333 and AFCONA-3777 on coating performance were examined, as shown in Table 9. as can be known from Table 9, acrylic leveling agent BYK-358, fluorocarbon modified acrylates leveling agent AFCONA-3777 although not affecting heavy coating, but in fluorocarbon coating leveling effect is not as good as modified silicone leveling agent BYK-306 and BYK-333, paint film gloss The comparison also supports this point, compared with BYK-306, BYK-333 can significantly reduce the surface pressure of the system, but if the dosage control is not good easily lead to no adhesion between coatings, affecting re-painting, so the test selected the better adaptability by BYK-306 as the system leveling agent, and its dosage was examined, the test results can be seen in Table 10. by Table 10, when the leveling agent BYK-306 in fluorocarbon coatings added 0.3%, the leveling effect of the paint film is good, re-coated barrier-free. 3 Conclusion (1) The re-allocation of N3390 and Z4470 as curing agents in the system can significantly shorten the non-staining time of the coating, extend the application period of the coating, while the hardness and weather resistance of the coating also have a certain degree of improvement and improvement. When the N3390 and Z4470 are matched with a mass ratio of 9:1, the comprehensive performance of the paint film is better. (2) Modified polyurethane-like polymer dispersant C with more anchoring groups and higher relative molecular mass has better wetting dispersion of fluorocarbon coatings, and the fluorocarbon coatings prepared have no floating flowering phenomenon, and the accelerated storage stability is good. (3) When the leveling agent BYK-306 is added to fluorocarbon coatings by 0.3%, the leveling effect of the paint film is good and the re-painting is barrier-free. Through the above conditions preferably prepared after the high solid fluorocarbon coating VOC content is low, with excellent weather resistance and corrosion resistance, high-performance fluorocarbon coating production and coating process greening and cleaning. : Part of the content of this article from the network, we have indicated the source, copyright owned by the original author! 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