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    Home > Coatings News > Coating Technologies > [Information of Tu Society] The road to water-based mechanical coatings is a long way to go!

    [Information of Tu Society] The road to water-based mechanical coatings is a long way to go!

    • Last Update: 2021-05-07
    • Source: Internet
    • Author: User
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    In the early 1990s, China's construction machinery industry entered a period of rapid development, and a large number of outstanding enterprises entered the international, integrated, and large-scale development.

    And after years of unremitting efforts, today, we can see that China's construction machinery industry has continued to grow and develop.

    The rapid development of the construction machinery industry has promoted the gradual integration of construction machinery coatings with international standards in terms of product structure, technical level, and coating technology, and production and sales have also increased significantly.

    Since 2011, China has become one of the countries with the largest production and sales of construction machinery in the world.

    my country plans to focus on promoting the construction of 150 major water conservancy projects from 2020 to 2022, with a total investment of about 1.
    29 trillion yuan, which will drive investment of about 6.
    6 trillion yuan.

    Under the background of loose monetary policy and the continuous promotion of "two new and one heavy" related projects, the infrastructure and real estate industries are booming, and the continuity of the boom cycle of the construction machinery industry is expected to exceed expectations.

    It can be said that construction machinery coatings have become an extremely important part of China's coatings industry.

    Construction machinery coating classification Of course, it is necessary for us to have a corresponding understanding of the classification of construction machinery coatings.

    If divided according to the coating, it can be divided into primer, middle coat and top coat.

    Primer is a basic paint that is applied to the surface of an object as a primer.

    Construction machinery, especially large construction machinery, is generally operated in the open air, directly in contact with air, moisture, impurities, and withstands wind and sun.
    Some construction conditions are bad.
    The adhesion and corrosion resistance of the coating mainly rely on this layer of primer.
    .

    The middle coat is a coating that connects the primer and the top coat.

    The main function is to fill the bottom substrate, isolate the defects of the primer layer, improve the fullness of the topcoat and other decorative properties, enhance the adhesion of the topcoat to the coating, increase the thickness of the entire supporting coating, and improve the entire The water resistance and anti-corrosion performance of the coating.

    For parts with low decorative requirements and parts with good flatness on the surface of the substrate, intermediate coating may not be sprayed, thereby reducing the cost of construction machinery products.

    Commonly used intermediate coatings are epoxy intermediate coating and polyurethane intermediate coating.

    The topcoat is the "coat" of engineering machinery products, which plays a decisive role in appearance and directly affects people's visual senses.

    It should be noted that the types of finishes for construction machinery have been diversified.

    The characteristics and types of construction machinery primer Primer is the most basic paint in construction machinery coatings, which is directly constructed on the surface of pre-treated iron plates.

    The primer on construction machinery must have the following characteristics: good adhesion to the substrate, and the coating film formed after construction should have excellent mechanical strength; at the same time, it also needs to have good compatibility with the upper coating-primer It has good construction performance and can adapt to different kinds of coating processes.

    Commonly used engineering machinery coating primers include epoxy ester primer, alkyd primer, epoxy primer, acrylic primer, polyurethane primer, and cathodic electrophoretic primer.

    According to the different purposes of the primer, the commonly used primers are: oil-resistant primer, anti-rust primer, and weldable shop primer.

    The anti-rust primer is used for the anti-rust protection of ordinary metal parts and has a good compatibility with the underlying coating: oil-resistant primer is mainly used near the hydraulic parts, and the coating film is required to have good resistance to oils such as engine oil and hydraulic oil.
    characteristic.

    Weldable shop primer is used after the pretreatment of the substrate is completed, before the formal primer is not coated, as a primer for temporary rust prevention, the coating film is required to have good weldability, and the construction coating is generally 5- 15um.

    According to the components of the primer, it is divided into two-component primer and single-component primer.

    One-component engineering primers are prone to under-bite and adhesion drop during the construction of solvent-based topcoats.
    Therefore, two-component epoxy primers have become the mainstream matching solution at present.

    Construction machinery requirements for primer primer is the prerequisite for the durability and beauty of the topcoat.
    The quality of the primer is an important factor affecting the appearance of the topcoat.
    The primer with poor performance may even peel and crack.
    Therefore, the choice of primer and its construction are very important.
    We can choose the primer for construction machinery from the following aspects.

    Anti-corrosion performance Construction machinery is basically stored in the open air and operated outdoors, and some even work in high humidity, high temperature, and high salt environments.
    Therefore, the anti-corrosion performance of the coating is very important for the life cycle and good appearance of construction machinery.
    .

    Its main performance tests include related standards and methods such as water resistance, oil resistance, heat resistance, and salt water resistance of the coating film.

    For hydraulic parts, the performance of various types of hydraulic oil is the most important.
    Otherwise, after the coating film is corroded, the coating film that falls into the hydraulic oil may cause the hydraulic system to malfunction, which will affect the daily operation of construction machinery.

    The primer sprayed on the surface of the heated parts must have good heat resistance, otherwise the coating film of the heated parts will fall off, causing the parts in this part to be directly exposed to the air, thus accelerating the corrosion rate of the construction machinery .

    Mechanical properties The mechanical properties of the engineering machinery primer mainly include impact strength, hardness, adhesion, flexibility and other properties.

    If the mechanical properties of the primer are not very good, then the coating film is easily damaged during the production, shipment, and work of the parts or machinery, thus losing the anti-corrosion properties of the primer.

    Construction performance The anti-corrosion performance, mechanical properties and other various properties of the primer must be constructed by the primer and realized after drying and film formation.
    Its construction performance will also affect the production efficiency, cost and appearance quality of construction machinery.

    The construction performance of the primer is mainly manifested in the performance of surface drying, hard drying, leveling, coating hiding power and construction adaptation period.

    If the primer drying time is too long or requires a high drying temperature, it will affect the spraying time of the lower coating, which will increase the construction cost: poor leveling of the primer will cause the surface of the coating film to be uneven after drying.
    When spraying the top coat, it is likely to have malaise such as low gloss and bad orange peel.

    The requirements of construction machinery for intermediate paint The intermediate paint is a coating that connects the primer and the top paint.

    The main function is to fill the bottom substrate, isolate the defects of the primer layer, improve the fullness of the topcoat and other decorative properties, and at the same time enhance the adhesion of the topcoat to the coating, increase the thickness of the entire supporting coating, and improve The water resistance and anti-corrosion performance of the entire coated object.

    Requirements of construction machinery for intermediate paint: good compatibility with primer and topcoat, strong bonding between upper and lower coatings; moderate hardness of the coating, the solvent of the topcoat cannot "bite" the coating, and it is resistant to water and humidity.
    The performance should be better, it will not cause the topcoat to foam, the sanding performance should be better, it can be dried at an appropriate high temperature, and when it is dry, it must not stick to the sandpaper and have good drying properties.

    Commonly used intermediate coatings are epoxy intermediate coating and polyurethane intermediate coating.

    The main reason for the selection of polyurethane intermediate coating is to consider that the coating film has better weather resistance.

    The requirements of construction machinery for the topcoat The topcoat can make the construction machinery have a high gloss, rich colors, and give people a sense of beauty.

    The effect of the topcoat directly affects the customer's judgment on the quality of construction machinery products, so the appearance color and effect are getting more and more attention.

    Commonly used solvent-based topcoats are alkyd, acrylic and chlorinated rubber, and polyurethane topcoats.

    The requirements of construction machinery for topcoat are as follows.

    Protective performance Construction machinery is generally constructed outdoors and stored outdoors.
    The working conditions are harsh and face the erosion of wind and sun, dust pollution and rain and cement water.

    Therefore, construction machinery needs paint protection to coat its surface with a certain thickness of coating film in order to isolate corrosive substances such as oxygen, moisture, dust and dirt in the atmosphere, avoid corrosion within a certain period of time, and ensure the service life of the equipment.

    It can be said that the protective function is the basic function of construction machinery coatings, so the coating film requires good adhesion, impact resistance, flexibility and other mechanical properties.

    Decoration performance At the early stage of the development of the domestic construction machinery industry, coatings were mainly used for anti-rust protection.

    After entering the 21st century, as the industry cakes become bigger and bigger, the competition becomes increasingly fierce.
    The appearance of the coating has also become an important factor in the competitiveness of products.
    Higher gloss, higher fullness, and pleasing coating color matching are natural It is easier to win the market.

    Also with the development of the market, construction machinery companies are also aware of the importance of brand building and corporate image visual identity (VI), so coating the product surface with paint plays an important role in brand communication.

    Construction machinery is large and complex in structure, and it is difficult to achieve high appearance effects on all surfaces.

    For this reason, the construction machinery industry puts forward the concept of covering parts, that is, parts covering the outside of machinery and equipment, including fuel tanks, cabs, engine hoods, cover plates, etc.
    , on these covering parts, highlighting the decorativeness of the coating, and requires The surface coating film is smooth, uniform, full, high gloss, no defects, and has a certain degree of weather resistance.
    The loss of gloss and fading within a certain period of time are within the specified range.

    Since 2000, the construction machinery industry has paid more and more attention to the appearance quality of products.
    The Beijing Construction Machinery Exhibition has also held appearance evaluation activities every two years.
    The decorative function of construction machinery coating has become more prominent, and users and manufacturers are paying more attention to products.
    The overall visual effect of the painting.

    Construction performance When selecting the top coat of construction machinery, attention must be paid to the compatibility with the primer, middle coat or putty, otherwise the entire coating may wrinkle and bite during the coating.

    The topcoat requires good leveling, high gloss, high vividness, and good fullness, but it must not sag.

    In the case of poor leveling performance of the topcoat, it may cause problems such as sagging, orange peel, poor freshness and poor fullness.

    At present, most of the products of construction machinery at home and abroad are still coated with solvent-based coatings.

    The use of low-construction solids solvent-based coatings will produce a large amount of volatile organic compound (VOC) emissions, causing serious pollution to the environment.

    In recent years, my country has promulgated and implemented a series of policies and regulations restricting solvent-based coatings.
    The traditional solvent-based construction machinery coatings market has been greatly impacted, and the demand for water-based construction machinery coatings is booming.

    In September 2013, the State Council issued the "Air Pollution Prevention and Control Action Plan", which clarified the comprehensive rectification of volatile organic compounds in the petrochemical, organic chemical, surface coating, packaging and printing industries, improved the volatile organic compounds limit standards for coatings and other products, and promoted their use Water-based coatings, encourage the production, sales and use of low-toxic, low-volatility organic solvents; on January 26, 2015, the Ministry of Finance and the State Administration of Taxation jointly issued the "Notice on Collection of Consumption Tax on Batteries and Coatings", announcing that since February 2015 Consumption tax on coatings will be levied on the 1st.

    Consumption tax is levied during production, commissioned processing and import.
    The applicable tax rate is 4%.
    The coatings with volatile organic compound (VOC) content of less than 420g (inclusive) under construction are exempted from consumption tax; in July 2016, the Ministry of Industry and Information Technology and The "VOC reduction action plan for key industries" jointly issued by the Ministry of Finance requires that by 2018, the VOC emissions of the industrial sector will be reduced by more than 3.
    9 million tons compared with 2015, and the use of solvents and additives such as benzene, toluene, and xylene will be reduced.
    More than 20%, and the proportion of green paint products with low (no) VOC reached more than 60%; in September 2017, the Ministry of Environmental Protection issued the "Thirteenth Five-Year Plan for the Prevention and Control of Volatile Organic Compound Pollution".
    The requirements are as follows: ① Focus on promoting container, Industrial coating emission control in the manufacturing industries of automobiles, furniture, ship tires, construction machinery, steel structures, coils, etc.
    : By 2020, the national industrial coating VOC emissions will be reduced by more than 20%, and key areas will be reduced by more than 30%.

    ②Promote use High-solid coatings, the use ratio will reach more than 30% by the end of 2020: Pilot implementation of water-based coatings, and actively adopt advanced coating technologies such as robot spraying and electrostatic spraying.

    Strengthen the collection and treatment of waste gas, and the collection rate of organic waste gas will not be lower than 80% of the waste gas from spraying and drying is treated by incineration.


    July 3, 2018: The State Council publicly released the "Three-year Action Plan for Winning the Blue Sky Defense".
    After three years of hard work (2018-2020), major reductions in major The total amount of air pollutant emissions will be coordinated to reduce greenhouse gas emissions, further significantly reduce PM2.
    5 concentration, significantly reduce the number of days of heavy pollution, significantly improve ambient air quality, and significantly enhance people's blue sky happiness.


    By 2020: sulfur dioxide, nitrogen oxides Total emissions were reduced by more than 15% compared with 2015; the concentration of PM2.
    5 in cities at the prefecture level and above decreased by more than 18% compared with 2015, and the number of days with good air quality in prefecture-level and above cities reached 80%, and the number of days with heavy pollution and above The ratio is down by more than 25% compared with 2015; April 27, 2020: At the 17th meeting of the Standing Committee of the 13th National People’s Congress, Deputy Minister of Ecology and Environment Huang Runqiu stated that this year will be formulated and implemented to win the blue sky defense war in 2020.
    Tackling tough action work plan.

    Focus on key tasks such as replacement of clean heating and bulk coal, ultra-low emission transformation of steel and other industries, and focus on the control of volatile organic compounds in key industries.

    Promote the establishment of joint prevention and control mechanisms for air pollution in the border areas of Jiangsu, Anhui, Shandong and Henan.

    Through the above measures, the comprehensive removal rate of VOC in the coating of construction machinery manufacturing has reached more than 50%.

    After the implementation of a series of environmental protection policies to reduce VOC, it is believed that the conversion speed of construction machinery coatings from traditional solvent-based coatings to environmentally friendly coatings such as water-based coatings will be greatly accelerated.

    The water-based paint itself is a paint that uses water as a dispersion medium, which can reduce VOC emissions during the coating process.

    The water-based coatings used in construction machinery are mainly two-component epoxy primer and two-component polyurethane topcoat.
    However, due to their performance and appearance, there is still a certain gap compared with high-quality coatings, and their environmental temperature and humidity are equivalent.
    It is sensitive and requires high surface pretreatment of the workpiece, so it is difficult to control the coating quality.
    Therefore, the construction machinery industry has a long way to go to achieve large-scale mature applications.

    It is reported that electrophoretic coatings are the first water-based coatings to be successfully applied.
    In order to meet different needs, cathodic electrophoretic coatings are developing very rapidly.
    Basically, they are updated every 3 to 5 years.
    At present, standard, low-temperature baking have been developed.
    Cathodic electrophoretic coatings such as type, thick type, corner covering type, weather resistant and durable type.

    Due to the absence of dead spots in electrophoretic coating, the overall anti-rust performance of the workpiece is greatly improved.
    It has been widely used in the coating of automobile bodies.
    It has also attracted more and more attention from enterprises in the construction machinery industry.
    At present, electrophoretic coating is used in the construction machinery industry.
    The application is mainly on covering parts such as cabs and hoods, and the application fields are also expanding.

    It can be said that improving the corrosion resistance of construction machinery coatings and the adaptability under various environmental and climatic conditions, the pursuit of higher appearance quality, lowering the curing temperature of the coating, and improving the construction adaptability and environmental friendliness will be the future of construction machinery The main attack direction in the field of coating research.

    Construction machinery coatings will also continue to pursue higher production capacity, efficiency, quality, and less materials and energy consumption from the aspects of materials, processes, equipment, etc.
    , and reduce or eliminate the three wastes.

    The demand for construction machinery products and the growth rate have a strong correlation with GDP and the scale of capital construction investment, especially in the industrial fields that have a significant impact on the country and society.

    With the continuous growth of China's national strength, the continuous improvement of social production needs and environmental protection needs, it is believed that water-based products of construction machinery coatings will follow the progress of the times and show an increasingly better development trend.

    This article is an English version of an article which is originally in the Chinese language on echemi.com and is provided for information purposes only. This website makes no representation or warranty of any kind, either expressed or implied, as to the accuracy, completeness ownership or reliability of the article or any translations thereof. If you have any concerns or complaints relating to the article, please send an email, providing a detailed description of the concern or complaint, to service@echemi.com. A staff member will contact you within 5 working days. Once verified, infringing content will be removed immediately.
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