[China Aluminum Network] Traditional solvent-based coatings have been widely used due to their good overall mechanical properties and surface properties. In recent years, many countries have successively promulgated laws and regulations concerning the control of volatile organic compounds (VOCs), which have led to the rapid development of waterborne coatings. With the pressure of environmental protection policies, people’s awareness of environmental protection continues to increase, and in particular, various provinces and cities across the country have issued VOC emission limit standards, which has brought opportunities for the development of environmentally friendly coatings such as water-based coatings in China. Although traditional solvent-based coatings still occupy a large market share, water-based coatings are the future direction of the coatings industry. In the following, in conjunction with the existing performance testing standards for water-based paints, the performance metrics that are not involved and the test items that need to be strengthened are discussed. 1 advantages and disadvantages of waterborne coatings Water-based paint uses water-based polymer as a film-forming substance, which reduces the VOC emissions, and has the advantages of safety, no fire hazards, and can be constructed in a humid environment with convenient cleaning. However, waterborne coatings also have their disadvantages: (1) Longer drying time during film formation, especially under low temperature and high humidity conditions; (2) Due to the large surface tension of water, it is difficult for the waterborne coating to wet the substrate. (3) Using water as a solvent, the metal matrix is ​​extremely susceptible to corrosion; (4) The compatibility of the film-forming resin and water is not good, so that the storage stability of the water-based paint is poor; (5) Because the freezing point of water is higher than most organic solvents, the freeze-thaw stability of aqueous coatings is poor; (6) Susceptible to microbial destruction. 2 existing water-based paint related performance testing standards With the development of water-based coatings, relevant standards are constantly being formulated. The existing product standards for water-based coatings are: GB/T 23999-2009 "Waterborne Wood Coatings for Interior Decoration", GB 24410-2009 "Interior Decoration Waterborne Wood Coatings, Harmful Substance Limits, HG/T 4570-2013 Automotive Waterborne Coatings, HG/T4758-2014 Waterborne Acrylic Resin Coatings, HG/T 4759-2014 Waterborne Epoxy Resin Anticorrosion Coatings, HG/T 4760—2014 Waterborne Dipping Paint, HG/T 4761—2014 Waterborne Polyurethane Coating, HG/T 4104—2009 Water-Based Fluorine Coatings, JT/T535—2004 Road and Bridge Water Based Pitch Base "Waterproof coating" and other; existing standards for water-based paint testing methods are: GB/T 18178-000 "water Coating Coating System Selection Rules, GB/T 31414-2015 "Determination of Surfactants for Waterborne Coatings, Alkylphenol Polyoxyethylene Ether", etc. Taking GB/T 23999-2009 “water-based wood coatings for interior decoration and decoration†as an example, the method for determining the drying time of waterborne wood coatings refers to GB/T 1728-1979 “Determination of the drying time of paint film and putty filmâ€; Sex test methods refer to GB/T 1768-2006 "Determination of abrasion resistance of paints and varnishes by rotating rubber grindstone method"; adhesion test methods refer to GB/T 9286-1998 "Drawing of paints and varnish paint films. Tests; freeze-thaw resistance is cited in GB/T9755-2001 "synthetic resin emulsion exterior paint" 5.5; hardness refers to GB/T 6739-2006 "paint and varnish pencil method to determine the film hardness The reference to dry heat resistance is GB/T 4893.3-2005 "Determination of Dry Heat Resistance of Furniture Surfaces". Taking HG/T 4570-2013 "Automotive Waterborne Coatings" as an example, the drying time of waterborne automotive coatings refers to GB/T 1728-1979 "Determination of the drying time of paint film and putty film"; the reference for cross-hatch adhesion test Is GB/T 9286-1998 "paint and varnish paint screening test"; impact resistance refers to GB/T 1732-1993 "impact resistance test method"; pencil hardness reference is GB/T 6739 -2006 "Painting paints and varnishes to determine film hardness"; bending test refers to GB/T 6742-2007 "paint and varnish bending test (cylindrical shaft)"; cupping test refers to GB/T 9753- 2007 Paint and Varnish Cupping Test. 3 Waterborne paint performance test items not covered by existing standards The above standards for these detection methods are mainly for solvent-based paint products, and water-based paints and solvent-based paints are completely different, and it is urgent to formulate corresponding test method standards for the characteristics of water-based paint products. For example, the temperature for the normal detection of the film drying time is (23±2)°C and the humidity is (50±5)%. Due to the long drying time of waterborne coatings, a method for the determination of the drying time of waterborne coatings under low temperature and high humidity conditions should be developed. According to the requirement of the water-based paint, the drying time of the water-based paint is measured under the condition that the set temperature is lower than 23°C and the humidity is higher than 50%. If the viscosity of the water-based paint is too low, sagging may occur and affect the quality of the construction. Can refer to the current national standard GB/T9264-2012 "paint and varnish sag resistance assessment" to test the sag performance of waterborne coatings, and make evaluations to reduce the construction problems. Water-based paints are highly corrosive to metal substrates and can be used for corrosion resistance testing of aqueous coatings on metal substrates, including salt spray resistance, water resistance, alkali resistance, and brine resistance. Among them, salt spray resistance can be measured with reference to GB/T 1771-2007 "Determination of Neutral Salt Spray Resistance of Paints and Varnishes"; water resistance can be determined with reference to GB/T 1733-1993 "Water Resistance Test Method for Paint Films". Determination; Alkali resistance can refer to GB/T9265-2009 "Architectural paint coating alkali resistance determination" for determination. The compatibility of the film-forming resin and water is not good, and the storage stability test of the water-based paint can be performed: the water-based paint is allowed to stand for a few days under certain temperature and humidity conditions, and it is observed whether there is delamination or aggregation and other undesirable phenomena. Determine the storage stability of waterborne coatings. The freezing point of water is 0° C. When the temperature is lower than 0° C., in winter, especially in the winter in the north, the construction of the water-based paint is greatly inconvenient. It is necessary to adjust the formulation of water-based paints for winter and add additives such as anti-freeze agents. At the same time, the low-temperature stability test of water-based paints in winter construction is also very necessary. The low-temperature stability test can refer to GB/T 9268-2008 “Latex paint resistance The measurement of freeze-thaw performance was performed. Waterborne paints are susceptible to mildew and other harmful substances that cause moldy growth. To examine the antifungal properties of waterborne paints, refer to GB/T1740-2007 "Mold Resistance Test for Paint Films". Strains include Aspergillus niger and Aspergillus flavus. The major difference between aqueous coatings and conventional solvent-based coatings is the use of water as the solvent, but most of the existing standards for water-based coatings do not address moisture content testing. Water content of waterborne coatings can be measured by reference to GB/T 606-2003 "General Method for Determination of Chemical Reagent Moisture Content by Karl Fischer". Karl Fischer's determination of water content is an accurate and mature method, but due to the uneven sampling of water-based paint products, the test results will be unstable. Having consulted the previous relevant standards, there is a National Standard GB/T1746-1979 (1989) “Moisture Determination Method for Coatingsâ€. Although this standard has been invalidated, this method is used in water-based coatings regardless of economy or convenience. The determination of water should be more appropriate. 4 Conclusion Although waterborne coatings are superior to traditional solvent-based coatings in terms of environmental performance, they are difficult to construct, water-resistant, crust-free, poor fullness, and poor hardness. Only when the physical properties of waterborne coatings are overcome, even beyond traditional solvent-based coatings, people will be more proactive in choosing waterborne coatings. If only the environmental performance meets the requirements, and the construction process and decorative effect can not meet people's requirements, the market of water-based coatings is still difficult to open. This requires water-based paint manufacturers to carry out technological innovations in the performance of water-based paints. It also requires relevant professionals to tailor-make water-based paint testing methods, and to formulate more and more suitable water-based paints to test the characteristics of the water-based paint industry. Develop faster.