Application of new film-forming additive ethylene glycol isosin ether in electrophoretic coatings.

the application of ethylene glycol isosin ether, a new film-forming additive, in electrophoretic coatings . Fang Dawn 1, Yuan Jixian 2, Gu Agile 1(1. Libang Coatings (China) Co., Ltd., Shanghai 201021; 2. Jiangsu Yida Chemical Co., Ltd., Jiangsu Jiangyin 214441)PreambleElectrophoretic coating is a membrane-forming material based on water-dispersed ionized polymers, in the state of water dispersion, using electrophoresis (electric deposition method) coating coating.like conventional solvent-based coatings and water-based coatings, electrophoretic coatings require the addition of a small amount of solvent, in addition to hydrophobic solvents, the need to add hydrophobic solvents, i.e. film-forming additives. Film-forming additives have the following three effects: (1) electrophoretic coating baking temperature is relatively high (regular 140 to 180 degrees C), much higher than electrophoretic emulsion film-forming temperature, but electrophoretic coating resin composition is more, very complex, the compatible between the resins is not necessarily very good, film-forming additives have a good solubility of various resins In the baking process, promote and maintain good compatible between the resins, so that the coating film curing uniform, (2) high boiling point, not easy to volatilize, baking to promote the coating film leveling, improve the appearance of the coating film, (3) adjust the thickness of the coating film, according to customer requirements, so that the thickness of the coating film stable to maintain within the target range, to ensure the quality of electrophoretic coating film.electrophoretic tank liquid organic solvent content is generally 0.5% to 3.0%, high boiling point solvent (film additives) about 30% to 50%, solvent content according to electrophoresis varieties and customer requirements vary. If there are too few film additives, coating film leveling is not good, the appearance is rough, thick and thin film, affecting the anti-corrosion performance of electrophoresis, if there are too many film additives, low coating voltage, film thickness is too thick, swimming permeability decreased. In the long-renewal cycle electrophoresis tank, the addition of membrane additives helps to maintain the stability of the electrophoresis tank fluid and reduce or avoid the hydrolysis of the resin. In electrophoresis production lines using galvanized plates, if pinholes occur, the addition of film additives can eliminate pinholes and improve pinhole resistance of electrophoresis coatings.commonly used electrophoresis film solvents are ethylene glycol ether, propylene glycol ether. Ethylene glycol ethers have glycol heteroether, ethylene glycol isoen ether, propylene glycol ethers have propylene glycol ether and so on. Ethylene glycol hexyl ether, glycol isosin ether manufacturers are very few, ethylene glycol isosin ether only Japanese emulsifying agent production, domestic imports from Japan, high prices, limiting the use and promotion of new electrophoretic film additives; Therefore, the development of cost-effective film-forming additive ethylene glycol isoxin ether is particularly important.1 Experimental part 1.1 Raw materials and equipment POWERNICS 150 BLACK electrophoretic tank liquid, Libang; ethylene glycol isosin ether, purity of 98%, Jiangsu Yida Chemical; ethylene glycol hexyl ether, purity of 98%, Japanese emulsion agent; propylene glycol ether (PH P), Jiangsu Yida Chemical; electrophoresis device, model AP -EC02, Japan High Sand Production Institute; Membrane Thickener, Model MiniTest 600BFN2, Elektro Physik; Gloss Meter, Model Micro-TRI-gloss, BYK; Roughness Meter, Model SJ-210, Mitutoyo; Salt Mist Tester, Model CZ-160A, Crowd-Chi Detection Instrument.1.2 Coating process (1) POWERNICS 150 BLACK electrophoretic tank liquid without membrane additives in mechanical stirring, 40 degrees C, 16 h for maturation, 25 m filter cloth filter spare;(2) Under stirring, slowly add film additives to the electrophoresis tank fluid, stir 2 h for plate making,(3) room temperature after placing 24 h, to detect the physical properties of electrophoretic coating film.
(4) salt spray test, according to ASTM B117, after removing water-based, remove rust, room temperature placed 2 h, with Switch tape pull, measuring the width of erosion.2 Results and Discussion 2.1 Basic parameters of glycol isosyl ether, glycol hexyl ether and propylene glycol etherC6H13OCH2CH2OH, ether bond and hydroxyl; propylene glycol ether structure: C6H5OCH2CH (CH3) OH, ether bond and mid-hydroxyl; ethylene glycol isoen ether (2EHG), ethylene glycol hexyl ether (HC) and propylene glycol ether (PPH) basic parameters are seen in Table 1.. 2.2 Comparing the effects of glycol isoen ether, glycol heteroether and propylene glycol ether Table 2, Table 3, Table 4 and Table 5 were the test results of plate making and coating after the slot solution was added to membrane additives 0, 0.5%, 1.0% and 1.5%.. 2.3 Advantages and disadvantages of various electrophoresis film additives 2.3.1 TexanolTwelve carbon alcohol esters with chemical names of 2,2,4-trimethyl-1,3-glycol monobutylate, ester-based and mid-hydroxyl. Although Texanol in latex paint is a conventional film-forming additive, low price, amphetamine or pure propylene or ethylene acetate system emulsion at room temperature film quality is good, but because of the chemical structure only ester bonds and medium hydroxyl, at high temperature (140 to 180 degrees C) dissolved amine modified epoxy resin capacity is poor, fluid level is not good, in electrophoretic coatings, has been almost non-use. 2.3.2 propylene glycol phenyl ether (PPH) propylene glycol phenyl ether due to relatively cheap, high temperature leveling is good, now more used in china, but propylene glycol ether coagulation point 11 degrees C, in winter need to be pre-melting treatment, increased production operation difficulties, second propylene Glycol ether (PPH) contains trace amounts of phenol, toxic, so it can be used as a fungicide, antiseptic disinfectant, in the electrophoretic coating wastewater treatment process to inhibit or kill bacteria, resulting in non-conforming wastewater treatment, there are environmental hazards, so around 2000, Japan basically stopped the use of propylene glycol ether. 2.3.3 ethylene glycol hethyl ether ethylene glycol hethyl ether high temperature leveling is good, but due to the raw material hethyl alcohol manufacturer less high price, ethylene glycol hethyl ether price is high, small fluctuations, the use of certain restrictions. 2.3.4 ethylene glycol isosin ether glycol isoenther is a colorless transparent liquid, slightly odor, water solubility is small, high boiling point, high temperature leveling is good, as a membrane additive for electrophoretic coatings, to ensure that the baking dissolves the components of each electrophoretic resin, even mixing and curing, so as to obtain the appearance and performance of excellent electrophoresis coating film. From Table 2 to Table 5, it can be seen that ethylene glycol isoen ether (2EHG), glycol heteroether (HC) and propylene glycol ether (PPH) are used in electrophoretic coatings: these three solvents are very good high temperature leveling, electrophoretic coating membrane appearance is very good, but the use of 2EHG coating film is more flat, PPH film surface is a bit foggy. Under the same addition and the same voltage conditions, 2EHG increase film thickness effect is best, when adding 0.1% to the tank fluid, 2EHG film thickness increase of about 2 to 3 m; Thus, in the case of increasing the same film thickness, 2EHG use is the least, 30% to 50% less than PPPH, although the price of 2EHG is slightly more expensive, but the overall cost of electrophoresis coatings will not rise. 2EHG boiling point of 229 degrees C, and the new policy requires boiling point of 260 degrees C is still some distance, but the solvent content in the formulation is reduced, the corresponding VOC is reduced; effect of ethylene glycol isosin ether on salt spray test
2EHG high boiling point, if left in the coating film, will affect the corrosion resistance of electrophoresis coating film. From Table 6 can be concluded: 2EHG in the electrophoretic coating baking process, the early stage played the role of dissolved resin leveling, the middle and late stage completely volatile off, not left in the coating film, so the electrophoresis coating film corrosion resistance does not affect. . 2.5 Methods and precautions for the use of glycol isosin ether 2EHG is added to electrophoretic coatings in a variety of ways: first, directly in resin synthesis as a solvent, in place of some other solvents, such as MBIK or glycol butyl ether; Liquid local flocculation; third, in the tank liquid directly slowly added, require stirring or circulation is better, added 2EHG immediately mixed into the tank liquid, especially in the production line, a supplement is relatively large, added 2EHG can not float on the liquid surface, the addition of the pipe exit is best in the pump suction pipe, negative pressure inhalation, after the circulation pump timely and tank liquid mixing uniform. 3 Conclusion In electrophoretic coatings, 2EHG added less, does not affect sewage treatment, good film-forming, cost-effective, so in Japan and South Korea, 2EHG has replaced PPPH, in the domestic Japanese and Korean paint manufacturers are also basically using 2EHG. Because ethylene glycol isosin ether has a very good film-forming and baking leveling, in water-based metal coatings as film-forming additives, foreign and domestic foreign large paint companies have matured for many years, China's paint hydration is the inevitable way, learn from foreign companies technology and experience, ethylene glycol isosin ether has a lot of room for development. the by-product of glycol isosin ether (2EHDG) is also a better film-forming additive, its boiling point of 272 degrees C, higher than the VOC requirement boiling point of 260 degrees C, so it can effectively reduce the VOC value of coatings, in water-based building coatings, water-based metal coatings, high-grade ink can be added to use.
ethylene glycol isosin ether in China only Jiangsu Yida Chemical Co., Ltd. production, foreign only Japan emulsifying agent Co., Ltd. and the United States Eastman Company (ethylene glycol isosin ether and diethylene glycol isosine ether mixture) production, the annual domestic demand of about 2,500 t, in the reduction of VOC, focus on environmental protection of the international trend, 2EHG in the electrophoretic coating industry has broad application prospects.
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