By Ji Hongyi, CNCIC
In recent years, the national and local governments have rolled out many environmental protection and safety policies and regulations related to the coating industry in a bid to promote the industry development in the medium-to-high end and green direction. As the main variety of low volatile organic compounds (VOCs) coatings, waterborne coatings have ushered in the rapid development phase.
Waterborne construction machinery coatings
The engineering machinery industry posted an explosive growth in 2017, as boosted by the infrastructure construction and real estate investment and the upswing extended in 2019. China’s construction machinery coatings output was nearly 100 kt in 2019. Waterborne coatings took a share of 10%, with the production volume at around 10 kt. The compound growth rate of output is expected at 9.3% in the following five years.
The primers used in the engineering machinery industry are mainly epoxy primers, and topcoats choose polyurethane (PU) coatings with better comprehensive properties. While agricultural machinery has lower requirements for coating corrosion resistance and gloss and color retention and tends to use alkyd coatings with general performance but lower prices. But due to the bearish market in recent years, waterborne coatings for the agricultural machinery industry are mostly epoxy primer with one-component or two-component PU topcoat.
Waterborne industrial wood coatings
China’s industrial wood coatings registered a sales compound growth rate of -1.9% in 2013-2019, as weighed down by the fluctuations in the real estate market and weak export market. In 2019, the sales volume stood at 1 120 kt. Stricter environmental protection policies, the rising furniture industry concentration level and consumers’ increasing awareness for environment protection gave support to the waterborne industrial wood coatings, which posted a double-digit growth in the past years. Technological improvement will help waterborne coatings to sustain a 10% growth rate in the coming five years.
Industrial wood coatings are mainly PU wood coatings, which boast good mechanical properties, weather resistance and fullness. PU wood coatings accounted for around 69% of the industrial wood coatings sales. In recent years, PU wood coatings will be gradually replaced by waterborne and UV wood coatings, due to environmental concerns. In 2019, the growth rate of waterborne industrial wood coatings stood at above 10% and is expected to remain high.
As for waterborne wood coatings, waterborne acrylic acid coatings are main products due to its convenient construction and high cost performance, accounting for about 65%. Waterborne PU-acrylic acid takes up 16% and has high weather resistance and good hardness. Waterborne two-component PU with high solid content, strong decoration, and durability and good chemical resistance occupies 10%. Waterborne UV accounts for 3%. 2kPU has a good development prospect as a topcoat because of its good film fullness and excellent chemical resistance.
Waterborne architectural steel structure coatings
As China is vigorously promoting the development of architectural steel structures and prefabricated buildings, the scale of the steel structure coatings market has been expanding, with the sales compound growth rate at nearly 10% in recent years. Of these, C1 anti-corrosion grade covers 3%, C2 anti-corrosion grade accounts for 8%, C3 anti-corrosion grade contributes to 66%, C4 anti-corrosion grade takes up 20% and C5 anti-corrosion grade occupies 3%.
In recent five years, waterborne steel structure coatings have logged in a growth rate of around 20% and will sustain a 20% growth in the coming five years. The coatings, with a proportion of nearly 90% are used in steel structure construction with anti-corrosion grade at below C3 or C4. Waterborne primers are the main variety, which contributes around 90% to the total sales. Its properties are similar to solvent primers. Water-borne primers are mainly water-borne inorganic zinc-rich primers, which account for about 60% to 70%. Waterborne epoxy zinc-rich primers cover around 10%. Waterborne alkyds occupy 10%-20%, and waterborne acrylic acid contributes to 10%-20%. Waterborne topcoats are difficult to meet the requirements of outdoor steel structure applications due to weather resistance, gloss and aesthetics, so the using volume is small.
Waterborne automotive coatings
Waterborne automotive coatings include waterborne original coatings, waterborne repair coatings, waterborne metal parts coatings and waterborne plastic parts coatings.
Passenger car body coatings generally use epoxy electrophoretic primer, which is currently 100% water-based. Therefore, waterborne passenger car coatings mainly refer to waterborne mid-coat and waterborne base paint. Among them, the waterborne intermediate coating generally uses polyester and modified resin, and the waterborne base paint is usually PU and hydroxy acrylic. The varnish still uses solvent-based coatings.
At present, only color coatings in China's passenger car repair coatings market have waterborne coatings, and the degree of water-based materials is relatively low, accounting for around 3%. In recent years, supported by the environmental protection policies, waterborne repair coatings have been developing rapidly. 4S stores of high-end brands such as Mercedes-Benz, BMW and Porsche all use waterborne repair coatings. While 70% of Audi 4S stores use waterborne repair coatings, and Ford 4S stores also have such requirements. Mazda, FAW Toyota, Lexus, etc. are gradually switching to waterborne coatings, while domestically-made automotive waterborne repair coatings find relatively limited applications.
In the past few years, waterborne coatings for automotive metal parts have achieved rapid growth, and water-based materials accounted for more than 20%. The ratio is expected to increase further in the future. In terms of the market segments, axles account for 34%, wheels cover 28%, diesel engines contribute to 7%, vehicle frames occupy 7%, shock absorbers account for 7%, and brake discs take up 3%. Others have a share of 14%. The water-based level of commercial vehicles is higher than that of passenger vehicles. The water-based process of axles and diesel engines is faster, and waterborne coatings account for 50-60% and 30-40%, respectively.
The plastic parts of passenger car include interior parts and exterior parts, which are mainly used in the steering wheel and other parts of the center control console of air bag cover. Waterborne plastic coatings for interior trim are mainly waterborne PU coatings. Due to the small market size of interior trim primer, it only accounts for about 10%. Waterborne plastic coatings for exterior decoration are mainly used for bumpers, and the fenders and spoilers produced in conjunction with bumpers also use corresponding waterborne coatings. Waterborne exterior plastic coatings are mainly waterborne paints. With the increasing requirements of passenger cars on the air quality inside the car, the trend of using water-based plastic parts for passenger cars is more obvious than that of exterior parts.
Development outlook
The "13th Five-Year Plan: Volatile Organic Compound Pollution Prevention and Control Work Plan" proposes to comprehensively promote the control of VOCs emissions from industrial coatings in the manufacturing industries of containers, automobiles, wooden furniture, ships, construction machinery, steel structures, and coils, and requires the removal of VOCs by 2020 by 50%~80%, and the replacement ratio to reach 30%~100% according to different industry segments. From the perspective of the water-based process of the industrial coatings sub-industry, sub-sectors with more obvious water-based level are the container, bus, auto parts, rail transit, construction machinery, steel structure, mechanical equipment etc.
During the "14th Five-Year Plan" period, the Chinese government plans to design emission reduction targets for the two prerequisites of ozone, VOCs and nitrogen oxides. Compared with the "13th Five-Year Plan", this will put forward higher and clearer work requirements for the reduction of VOCs, and an upgraded version of the blue sky defense action plan is under development. Faced with opportunities and challenges, the coating industry needs to continuously improve environmental protection technologies and provide high-quality low-VOCs coatings and coating solutions for downstream industries. Waterborne industrial coatings will brace for a broader development room.
