Water-based solutions for solvent-based alicic acid coatings for steel structures

China's steel structure market is growing rapidly, its anti-corrosion market is huge, is currently mainly solvent-based systems, of which solvent-based alicic acid system in China's coating history plays an important role, it is estimated that the total amount of solvent-based aolic acid coatings in 2017 more than 700,000 tons. Due to environmental protection policies and VOC solvent tax, steel structure with solvent-based alcoholic acid system oil to water is imminent. Due to the high light and resistance of solvent-based alicic acid paint, the water-based acrylic acid system is generally replaced, but many products are difficult to achieve the corresponding performanceChina
. In this paper, the water-based acrylic resin MAINCOTE™ HG-100 high-gloss emulsion as a film-forming substance, supplemented by suitable pigment fillers and additives, prepared a water-based acrylic coating with excellent gloss display. Based on the acrylic resin prepared white highlight coating gloss up to more than 95 (60 degrees angle), and has excellent early water resistance and salt spray resistance, applicable to a variety of steel structures, fences, road guardrails, industrial components, trailers, fences and so on. Compared with solvent-based aolic acid system, gloss and resistance are comparable, in terms of drying speed and weather resistance than solvent-based aolic acid system has a greater advantage.
Introduction
China's steel structure market grew rapidly, with a high growth rate of more than 15.0% from 2011 to 2016. The 12th Five-Year Plan puts forward the strategic goal of doubling the output of steel structure in 2015 compared with 2010, and promotes the rapid development of steel structure industry. In 2014, General Secretary Xi Jinping put forward the concept of "building the Silk Road" economic belt from the concept into a stage of pragmatic cooperation, infrastructure construction along the way for China's steel structure enterprises to bring new development opportunities, steel structure industry will continue to maintain the momentum of rapid growth. The goal of the 13th Five-Year Plan steel structure is to double the national steel structure output by 2020 from 2014 to 80 million tons to 100 million tons.
of steel structures has led to the rapid growth of the anti-corrosion coatings industry. The solvent-based alcoholic acid system in steel structure anti-corrosion coating accounts for a relatively large, according to incomplete statistics 2017 solvent-based alcoholic acid coating total of more than 700,000 tons, is currently the largest domestic production of a single category of coatings, generally used in steel structure, metal protection, agricultural machinery, engineering machinery and other applications, with cheap, simple construction, the construction environment requirements are not high, paint film plump, high gloss, decorative and protective advantages. However, solvent alkyd paint is slow to dry, VOC content is high, and very easy to powder, poor weather resistance. Traditional solvent-based alicic acid paint contains a large number of solvents, as well as drying agents, pigments, etc., in the production and construction process will seriously endanger the environment and the health of operators. In recent years, with the increasingly strict environmental regulations, traditional solvent-based coatings have been increasingly challenged.
water-based acrylic emulsions with fast drying, good weather resistance, corrosion and good water resistance characteristics, but also can achieve a high gloss and plumpness. Many domestic paint enterprises have invested in the development of steel structure water-based anti-corrosion coatings, research and development of a single-part water-based acrylic primer and finish, but the water-based acrylic paint gloss is still poor, aesthetic and resistance can not be comparable with solvent-based alcoholic acid system. The standard HG/T 5176-2017 for water-based anti-corrosion coatings for steel structures has been officially implemented on April 1, 2018, and the product standards will help regulate the market for water-based anti-corrosion coatings for steel structures, which will lead and promote the promotion and development of water-based anti-corrosion coatings products.
With this in mind, Dow Chemical's Asia Pacific Research and Development Center has developed a water-based acrylic MAINCOTE™ HG-100 highlight emulsion dedicated to the preparation of highlight paints to replace solvent-based aolic acid systems. In this paper, A water-based acrylic coating based on MAINCOTE™ HG-100 is prepared, and the relevant paint film performance is tested, and its performance is evaluated and tested.
experimental part
main raw materials and instruments
raw materials: titanium white powder, Komu; sodium nitrite, local; steril esters, Isman; dispersants, desmoulators, thickeners and other additives, Dow Chemical; DOWANOL™ DPM glycol, Ether Dow Chemistry; Instruments: high-speed dispersion machine, Shanghai Modern Environmental Engineering Technology Co., Ltd.; Degree meter, Bick Chemical, Germany; Rotary viscosity meter, Brookfield, USA; Laser particle size analyzer, Brooke Hevin Instruments, USA; Salt mist test box Q-Fog, accelerated aging test box, US Q-Lab; analytical balance, Meitler-Tolido, Switzerland; DSC differential scanning thermometer, Waters Technology Co., Ltd.; Spray gun, Iwata Iwata, Japan; dry film thickness meter, local enterprise.
preparation of high-gloss coatings
water-based acrylic emulsion MAINCOTE™ HG-100 preparation of high-gloss paint coatings, preparation formulations as shown in Table 1, including the pulping phase and painting phase.
paint film preparation
will be based on MAINCOTE™ HG-100 emulsion prepared high-gloss anti-corrosion coating using air spray or wet film preparer scraping film, etc. , the coating will be covered on the corresponding substrate, and then at room temperature conditions to maintain a certain period of time, after drying test paint film thickness and paint film properties.
film performance test
paint film related performance reference to the corresponding test standards are as follows:
reference GB/T1743-1979 test paint film gloss; 1 Test paint film salt spray resistance, reference GB/T1733-1933 test paint film water resistance and early water resistance, reference GB/T9286-1998 test paint film adhesion, reference GB/T1865-2009 test paint film weather resistance.
results and
the gloss of the paint film
solvent-based alcoholic acid system is better gloss, good construction performance and so on. Many products are hard to achieve such luster. The results of the ™ of THECOTE-based HG-100 compared to the well-known solvent-based alicic acid paint on the market are shown in Table 2 below. Just as Table 2 can achieve its paint film gloss can reach 96 (60 degree angle), compared with solvent-based alicic acid paint film is very close to the construction performance is similar, but the water-based acrylic system VOC content is much lower than solvent-based aliclicic acid system, the odor is much smaller, with obvious environmental protection.
From the drying performance data, it can be seen that THECOTE™ HG-100-based white paint products have obvious fast drying performance, in table dry and do-it-do performance are better than solvent-based aliclicic acid system, and this performance
has been recognized by many customers. Therefore, from the physical performance point of view, based on MAINCOTE™ HG-100 preparation of paint samples in a number of water-based acrylic anticorrosive paint has a higher gloss, faster drying speed, as well as lower VOC emissions, so the product client recognition is relatively high.
White high-gloss coating resistance test
an early water resistance test
many steel structure outdoor construction, especially in the summer may have sudden changes in wind and clouds, heavy rain events, if the early water resistance of the paint film is relatively poor, it will affect the appearance and performance of the paint film, such as foaming, rust, shedding and other issues, so the steel structure water corrosion coating for the early water resistance of the paint film has a relatively large performance requirements.
water resistance is an important performance of steel structure anticorrosion coating. We selected some well-known competitions on the market to compare early water resistance. Using the same formula for comparison, the use of wet film preparation wet film in about 200um, coating dry film in 45 to 55um or so, dry 75 minutes after direct deionized water immersion, soaking for 200 hours (about 8.3 days), from the test results can be seen, MAINCOTE™ HG-100 showed excellent early water resistance, found no Bubble and rust phenomenon, while other products have appeared in varying degrees of foaming or rusting, such as asking MAINCOTE™ HG-100 excellent early water resistance mainly stems from the fast drying performance of MAINCOTE™ HG-100, fast drying can provide better paint film strength and paint film resistance, for the establishment of early water resistance performance has a greater help.
performance test of salt
steel structure water-based anti-corrosion coating as a light anti-corrosion performance is salt spray resistance. Generally salt spray resistance performance is short 72 hours, long takes 150 hours, MAINCOTE™ HG-100 corrosion performance? First of all, the wet film preparation device prepared about 250um wet film, dry film thickness of about 60 to 75um, after seven days of maintenance according to ASTM B-177 test method for testing.
as shown in Figure 2, mainCOTE™ HG-100 has excellent salt mist resistance for comparative emulsion products on the market, and other products have different degrees of foaming, rusting and other problems. From this
it can be seen that the high-gloss paint based on MAINCOTE™ HG-100 has good corrosion resistance, the paint film is dense, can provide long-term protection performance.
Paint film weather resistance performance comparison
steel structure anti-corrosion coating for weather resistance also has certain requirements, but commonly used solvent-based alkalic acid system, weather resistance is relatively poor, the surface is prone to loss of light, powdering and other phenomena, many coatings are generally one coating a year, and even half a year, resulting in waste of manpower and resources. And because of the rising labor costs and the introduction of environmental protection policies, solvent-based alcoholic acid system oil-to-water is imminent.
with aluminum plate as the substrate, the preparation of paint film for 50 to 60um dry film thickness, and then put into the QUV-A 340 test box, the test results shown in Figure 3, based on MAINCOTE™ HG-100 high-gloss coating and solvent-based alcoholic acid weather resistance comparison test results. From the test results, it can be seen that mainCOTE™ HG-100 did not powder phenomenon occurred, and there is a good photon preservation, the test data of E is only 0.78. The solvent-based alcoholic acid system has a serious powdering phenomenon, almost no gloss, performance dropped sharply, as high as 8.3, according to the requirements of weather resistance can be seen, compared to solvent-based alkalic acid system, MAINCOTE™ HG-100 has good weather resistance, suitable for outdoor steel structure applications, will not appear powdering and other problems.
results of the adhesion test of the paint film
The adhesion between the coating film and the substrate is mainly affected by the functional group in the resin, and different functional groups will have a greater impact on the adhesion. Adhesion mainly has three forms of expression: physical adsorption, chemical adsorption and chemical co-price bonds. The adhesion of different substrates is also different. Common metal substrates are shown in Figure 4 below.
as shown in Figure 4, the high-gloss paint based on mainCOTE™ HG-100 has excellent adhesion performance on a variety of substrates, and even the more difficult to attach galvanized plate, horse port
iron plate and aluminum plate have good adhesion. MainCOTE ™ the functional group contained in HG-100 is of great help to enhance the adhesion of various substrates.
conclusion,
paper mainly studies the water-based solution of steel structure replaced by solvent-based alcoholic acid. High-gloss paints prepared with MAINCOTE™ HG-100 exhibit excellent high gloss and early water resistance, resulting in a finish for indoor and outdoor steel structures with high overall performance. The coating prepared with the acrylic emulsion MAINCOTE™ HG-100 has excellent gloss display, excellent early water resistance and excellent salt spray resistance. 0 degree angle can reach more than 95, wet film dry 75 minutes after soaking deionized water 8.3 days will not have any foaming phenomenon, with other emulsions on the market relative to the relative, with a relatively large performance advantage, while salt spray resistance also has a good performance. In summary, the MAINCOTE™ HG-100 acrylic emulsion is a resin that can prepare high-gloss coatings, prepared high-gloss coatings with the relevant properties to replace solvent-based aolic acid system, and is a low VOC, low odor environmental protection solution.
Refester
1 Applied research on water-based coating of steel structure; Huadong bolt (J) steel structure; 12th issue
2 steel structure preparation and performance research with high gloss high hardness water-based acrylic paint; Hu Meng (D) South China University of Technology 2013
3 Construction steel structure corrosion engineering and maintenance; Li Hongshan, Su Zhiliang; Construction Technology and Design, 2015

4 Development of New Water-based Steel Structure Coatings; 2
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Thanks
to Chen Hui, Yu Mingqu, Li Yaobang, Gao Yufeng, Tang Jia, Zheng Baoqing, Ling Hua, Cai Yu, Yu Dong, Guo Yan, etc. for their hard work on this project.
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