Traditional solvent-based industrial coating enterprises are transformed and upgraded to waterborne, powder and other environment protection directions more and more rapidly with more and more stringent environment protection regulations. Waterborne polyurethane coatings, waterborne epoxy resin coatings and waterborne acrylic resin coatings are fields with most attention among various waterborne coating systems. Three waterborne industrial coating product standards formulated by National Coating and Paint Standardization Technical Committee (SAC/TC5) will be formally implemented since June 1, 2015, including HG/T4761-2014 'Waterborne Polyurethane Coatings', HG/T4759-2014 'Waterborne Epoxy Resin Anticorrosive Coatings' and HG/T4758-2014 'Waterborne Acrylic Resin Coating', etc. Implementation of the standards will become an important milestone for waterborne industrial coating development process in China.
Currently, waterborne polyurethane coating market is just started in China, and large scale is not actually formed. However, Waterborne polyurethane coatings must enjoy flourishing development opportunities with general improvement of environmental protection awareness in all walks of life, especially more and more stringent
requirements on coating VOC contents according to environmental protection laws and regulations in different countries, gradually matured technology as well as lower and lower raw material cos. HG/T4761-2014 'Waterborne Polyurethane Coating' new standard is applicable to room-temperature air-drying one-component and double component as well as single-component high temperature baking waterborne polyurethane coatings with water as dispersion medium and polyurethane resin as main film former, wherein pigment (not added in varnish) and additives are added, the coatings are applied on the surface of metal, cement mortar, concrete and other inorganic non-metallic base materials, which have the functions of decoration and protection. In the standard, waterborne polyurethane coatings are divided into coating for metal surface and coating for inorganic nonmetallic surface, and related technical indicator requirements are respectively proposed.
Epoxy coatings account for quite considerable proportion among anticorrosive coatings for steel structures. Traditional solvent epoxy coatings produce a large amount of volatile organic volatile impurities in the production and construction process. Therefore, waterborne development of epoxy resin has been put on the agenda. Although waterborne epoxy resin has been studied for more than 25 years, waterborne epoxy coatings also have been applied for more than 10 years, waterborne epoxy resin and waterborne epoxy coatings with waterborne epoxy resin as base are not produced and applied in large scale from the perspective of overall application. Currently, the quality and protection effect of waterborne epoxy anticorrosive coatings in the market are not desirable, and coating accidents are frequently produced. Therefore, an industry standard is required to regulate production, construction and application of the coatings. HG/T4759-2014 'Waterborne Epoxy Resin Anticorrosive Coating' new standard is applicable to waterborne epoxy resin anticorrosive coatings for metal base, and related technical index requirements are proposed for primer, intermediate coat, and finish coat respectively.
Waterborne acrylic resin coating products not only can be used for protecting steel and other metals in industrial and civil fields, but also can protect cement or wood under many conditions. The waterborne coatings have larger competitiveness in the aspects of environmental protection, performance and price, including climate ageing resistance, reduction of content of volatile organic compounds, etc. The product has been considerably popularized in foreign countries, and it is applied in China more and more widely. There are many waterborne acrylic protective coating products in the market currently. They are different in product quality, environmental protection and construction effect since there are no unified standards and specifications. HG/T4758-2014 'Waterborne Acrylic Resin Coating' is suitable for waterborne one-component or double-component coatings with acrylic resin as main film former. The product is mainly used for decorating and protecting metal surface. In the standard, waterborne acrylic resin coatings are divided into type I baking cross-linking curing coating, type Ⅱ air-drying one-component coating and type Ⅲ room temperature cross-linking curing double-component coating. Related technical indicator requirements are respectively proposed.