The research status and application of water-based marine coatings

China Coatings Online News Information
Zhang Wenxuan (China Shipbuilding Heavy Industry Corporation, 725th Research Institute, Luoyang, Henan 471023)
Abstract: A summary of the classification, research status and application of water-based marine coatings, with a view to a more comprehensive understanding of water-based marine coatings.
key words: water-based marine coatings, research status quo, application
in the figure classification number: TQ 630.7 document identification code: A article number: 1009-1696 (2015)0 3-0026-04
0. Introduction
The successful development of water-dispersed resins has given the coating industry new vitality and prospects, so that coating production from dependence on organic solvents, natural resins, to solvent-free coatings and water-based coatings. Among them, water-based coatings have the largest market share and the fastest growth rate. Japan, Europe and the United States water-based paint market share is more than 60%, and in China this proportion is significantly lower. It is hoped that in the next five years, China's water-based coatings market share can reach 20%.
1. Classification of water-based marine coatings
Water-based coatings include water-soluble coatings, water-diluted coatings and water-dispersed coatings (latex coatings). At present, water-based coatings used in ship anti-corrosion can be matched with water-based coatings as well as solvent-based systems. The types of water-based marine coatings in China can be found in Table 1.
requirements for water-based marine coatings:
(1) waterline, outer string, deck. Due to corrosion caused by alternating wet and dry, damage caused by wave impact and aging caused by ultraviolet radiation, the coating should have good resistance to seawater corrosion, excellent physical and mechanical properties, wear resistance, impact resistance and weather resistance.
(2) upper structure. The coating should have good decoration and weather resistance.
(3) carriers, dry shelves, and place debris or food. The coating should be resistant to high humidity, high temperature, alternate heat and cold, wear resistance, chemical resistance and other characteristics.
(4) crude oil tanks, ballast tanks, waste fuel tanks, etc. The coating should be oil-resistant, sea-resistant, and electrochemically anti-corrosion.
(5) drinking water tank, water tank. Drinking water test qualified, and water resistance.
(6) cargo hold. According to the loading type (petroleum products, chemicals, etc.), the coating should be oil-resistant, chemical-resistant, acid-base-resistant, etc.
(7) chimneys, pipes. It is resistant to high temperatures of 500 degrees C and is fully compliant.
2. The research status of water-based marine coatings
Water-based inorganic zinc-rich coatings are one of the most important anti-corrosion coatings in water-based coatings. It is an inorganic material as the main film, high content of zinc powder as anti-rust pigment, water as a dispersion medium of high solid thick film coating, is the marine environment anti-corrosion field of the most excellent anti-rust performance of a class of coatings. Water-based inorganic zinc-rich coating as a zero VOC (volatile organic compounds) environmental protection anti-corrosion coating, has been accepted by all walks of life, with broad prospects for development and application. In recent years, there have also been water-based inorganic phosphate zinc-rich coatings, the substrate treatment requirements are relatively low, excellent performance. For example, the Zinga zinc-rich coating developed by Galvatech Led in Germany contains 95% zinc and has been in use for many years, with excellent corrosion resistance. In recent years, China's water-based high-module potassium silicate, lithium silicate zinc-rich coatings have been applied in engineering, performance is also constantly improving.
In addition to water-based inorganic zinc-rich coatings, water-based coatings such as thick slurpolic acid, epoxy, acrylic modified alcoholic acid or epoxy and polyurethane have reached the stage of industrialization and practical application, which can greatly improve the construction environment when used in the inner cabin and the bottom surface of the oil tank. However, because the ship is located in a relatively harsh environment, water-based coatings anti-corrosion effect is not up to the requirements, so that water-based coatings in the ship's application is less.
China's water-based ship cabin coating manufacturers are very few, including the Marine Chemical Research Institute Qingdao Haijian Chemical Co., Ltd. supporting coating products are more complete, mainly water-based acrylic cabin coating, water-based alcoholic acid cabin coating, water-based epoxy acrylic interior cabin coating And water-based epoxy cabin coatings, the above products have passed the highest level of domestic authorities toxicity and flame resistance testing, to meet all types of civil and military ships in the inner cabin coating requirements, and has been used in a large number of real ships, the main performance indicators see table 2 to 4. 3. Application of water-based marine coatings
The most common water-based anti-corrosion coatings are mainly three systems: acrylic system, epoxy system, inorganic zinc-rich silicate system, in addition to alcoholic acid system, butyl rubber system, asphalt system and fluorocarbon resin system. At present, there are several kinds of water-based coatings used for cabin corrosion protection.
3.1 Water-based acrylic anti-corrosion coatings
water-based acrylic anti-corrosion coatings with acrylic resin as the base material, and then with modified resins, pigments, additives, solvents, etc. prepared, with weather resistance, light preservation, color preservation and so on. Recent research more water-based iron-red acrylic anti-rust paint belongs to self-drying paint, with excellent adhesion, corrosion resistance and anti-fouling properties, and can be used with alcoholic acid, nitro, ammonia and other surface paint, in some respects, the performance is better than red danphenol anti-rust paint and red danol acid anti-rust paint.
3.2 Water-based epoxy anti-corrosion coating
early use is more epoxy asphalt anti-corrosion paint, mainly used in ballast water tank, long pipeline, long natural gas pipe and other corrosion-prone pipe exterior wall, but because of the paint asphalt cancer problems, it must be modified. Now the popular practice is to use phenolic petroleum resin instead of asphalt and modified epoxy resin, the formation of steel corrosion is small, easy to coat, easy to repair, harmless to the human body color water-based epoxy anti-corrosion coating. The special-effect water-based epoxy anti-corrosion coating developed can be applied after being rinsed with ultra-high pressure water only, and the anti-corrosion effect is remarkable. Now water-based epoxy anti-corrosion coatings have been applied to solvent-based epoxy anti-corrosion coatings involved in various fields. Reportedly: Japan in the new bridge design of water-based epoxy anti-corrosion coating, can reduce VOC (volatile organic compounds) 98%, after coating 3 a field performance test results and solvent-based epoxy anti-corrosion paint equivalent. Several types of water-based epoxy anti-corrosion coatings in the United States have met U.S. military coating standards and are used as aircraft primers. Water-based epoxy antiseptic coatings have been used in nuclear power projects and railway vehicles in Germany. Norway has developed a water-based epoxy anti-corrosion coating containing active pigments that can be used at low temperatures of -30 degrees C and can be used in ship casings.
3.3 Water-based inorganic zinc-rich anti-corrosion coatings
water-based inorganic silicate zinc-rich anti-corrosion coatings are divided into ethyl silicate and silicate series, of which the silicate series includes lithium silicate, sodium silicate, potassium silicate and other varieties, is an important part of steel anti-corrosion coatings. The coating uses the strong activity of zinc powder for electrochemical cathode protection to prevent steel corrosion, while zinc can react with inorganic polymers (silicates, phosphates, heavy chromates, etc.) to form a zinc-iron compound layer on the steel surface. The coating has excellent corrosion resistance, weather resistance, thermal resistance, water resistance, resistance to a variety of organic solvents, at the same time has a good electrostitive and long-term cathode protection, and good welding performance, with paint welding, long-term resistance to 400 degrees C high temperature, long-term resistance to pH 5.5 to 10.5 range of chemical corrosion, more important is no pollution to the environment, no impact on human health.
3.4 Water-based fluorocarbon coatings
water-based fluorocarbon coatings with excellent high temperature resistance, weather resistance, drug resistance, corrosion resistance, stain resistance and cold resistance, especially with food contact, can ensure food hygiene and safety, coating protection effect of up to 20 a long, with broad market prospects. The coating is divided into baking type and self-drying type, and the performance of Teflon type and Teflon type is the best, the most widely used, the simplest construction. However, the application of such coatings on ships is still in its infancy.
3.5 Water-based polyurethane coatings
Water-based polyurethane coatings are one of the fastest growing coating varieties, generally divided into single-component water-based polyurethane coatings, two-component water-based polyurethane coatings and composite modified water-based polyurethane coatings. Water-based polyurethane coatings can be mixed with other water-based dispersions, to complement each other, according to the need to adjust the formulation, adapt to a wide range, some performance even more than similar solvent-based coatings. In addition, it also has the following characteristics:
(1) water-based polyurethane coatings on metals, wood, concrete and plastic surfaces have good adhesion, weather resistance, impact resistance and wear resistance, especially water-based fatty polyurethane coating properties and solvent-based polyurethane coatings;
(2) Compared with other latex coatings, low-temperature film-forming effect is good, no film-forming additives, no need for emulsifiers, dispersants or plasticizers, etc.;
(3) easy to improve chemical resistance, solvent resistance and water resistance through curing agents and crosslinkers, can provide high gloss coating, a variety of pigments including metal pigments have good adaptability;
(4) polyurethane molecules are tailorable, combined with new crosslinking technology to effectively control the composition and structure of polyurethane coatings, providing a broader way to improve their overall performance.
although water-based polyurethane coatings have been used for a relatively short time, they have been widely used in paper, wood, leather, automotive, industrial maintenance, plastics and other fields. Two-group water-based polyurethane coatings can also be used in cement, tiles, roofs, stainless steel, golf clubs, etc. Although water-based polyurethane coatings have been widely used in light industry, construction, home improvement and other industries, but these coatings are rarely used as heavy anti-corrosion coatings on ships, so the study of marine heavy anti-corrosion water-based polyurethane coatings has significant theoretical and application value.
3.6 Marine water-based reflective insulation coating
ship water-based reflective insulation coating is widely used in the ship's cabin, cabin, crude oil cabin, inner cabin and other compartments, a good solution to the solar direct radiation caused by the rise in cabin temperature caused by a series of problems, improve the safety of ship operation, while saving energy, reducing greenhouse gas emissions and shipping costs, is a cost-effective and practical product. However, the coating can only unilaterally improve some performance, while other performance can not take into account, which requires us to develop and use modern polymer materials, improve other properties of the coating, to meet customer demand, that is, the future of marine water-based reflective insulation coatings to multi-functional, generalization, practical, engineering direction of development.
4. Conclusion
countries around the world invested a lot of manpower and material resources, after more than twenty years of efforts to overcome the difficulties of water-based paint, China is the development of water-based coatings included in the national "Fifth Five-Year Plan" project. As water-based coatings mature in technology, water-based inorganic zinc-rich coatings, low-treatment surface rust-proof coatings, etc. are more and more widely used in ships.
China as the world's second largest shipbuilding country, the current shipbuilding enterprises to undertake new ship orders in the load of million tons of quantity above the number of up to 8, in the next few years, China's shipbuilding completion volume will continue to rise, offshore equipment manufacturing industry will also achieve rapid development. In China, whether it is the relatively mature marine coatings market, or the continuous development of marine equipment coatings market, will maintain a good growth trend. During the "12th Five-Year Plan" period, China should continue to focus on stimulating domestic demand and implementing the ten major industrial revitalization plans, focusing on the development of marine coatings, heavy anti-corrosion coatings, special coatings and other high-tech, high value-added products. Water-based ship anti-corrosion coating saves energy, reduces the pollution of solvent-based coating to the environment, reduces the fire hazard of coating, improves the efficiency of shipbuilding, successfully solves the environmental, energy and safety problems, is an environment-friendly coating products, in line with the development needs of international environmental protection coatings, but also in line with the direction of building a sustainable society in China.
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