This article summarizes current compulsory coatings standards and those under development, providing useful information for formulators, technicians and standards researchers.

China has been the largest producer (10 million tons in 2011) and consumer of coatings since 2009, surpassing the United States.  Consequently, no one can ignore China’s coatings market; China has become the focus of international concern. Many international coatings companies such as PPG, Valspar, AkzoNobel and Nippon have built their factories in China, and some companies have built their research centers there as well.

With the high-speed development of China’s coatings industry, the technology has greatly advanced. The direct evidence is the continuous development of coatings standards, some of which are compulsory standards. The standardization law of the People's Republic of China (PRC) stipulates the standards for safeguarding human health and ensuring the safety of persons and property, and those for compulsory execution, as prescribed by the laws and administrative rules and regulations. Compulsory standards, different from voluntary standards, are the minimum quality requirements of products. All coatings products sold in China are required to meet the requirements of these standards.                 

Compulsory Coatings Standards in China

After years of continuous effort, there are more than 400 coatings and related standards in China, including national and industrial standards, which form a complete standard system. Of these standards, 58% are general, basic and method standards, and 39% are product standards.

The compulsory coatings standards are listed in Table 1 (see Appendix).^1-22 The compulsory coatings standards in China come from technical committees (SAC/TC) and administrative departments, and can be classified into national standards (labeled as GB) and industrial standards (labeled as JC, abbreviation of the building materials industry). If there are no corresponding national standards, the related industry organization can develop standards for application under administrative approval. Standards developed by different industry organizations are labeled with different letters.

SAC/TC5 (National Technical Committee 5 on Paints & Pigments of Standardization Administration of China) is a professional technical committee for coatings, and a technical counterpart of the International Organization for Standardization Technical Committee for Paints and Varnishes ISO/TC35. SAC/TC5 organized the development and modification of most of the coatings standards in China’s coatings standards system. Other technical committees, like SAC/TC 195 and administrative departments like the Ministry of Health (MOH) of the PRC, have contributed to the compulsory standards system as well. Generally, coatings standards promulgated for more than five years are regularly reviewed. SAC/TC 5 organizes experts annually to review the current standards. Experts evaluate the progress, effectiveness and applicability of standards, and suggest if they should be continued, modified or abolished.

GB 21177-2007 and GB 19457-2009, safety standards for inspection of hazardous properties and packaging, have been developed by SAC/TC 251, which manages the dangerous chemicals. All other standards specify the requirements for coatings products including:

•   wood coatings (solvent-/water-based);

•   architectural coatings (interior/exterior/waterproof coatings);

•   coatings for toys;

•   automotive coatings;

•   drinking water tank coatings of shipbuilding;

•   fire-resistant coatings;

•   inner coatings of food containers; and

•   radioactive luminescent paint.

GB 12441-2005 and GB 14907-2002, which specify the requirements for fire-resistant coatings, were developed by SAC/TC 113 under the management of the National Technical Committee 113 on Fire Protection.

The earliest compulsory coatings standards that are still effective are food container standards, which were developed by MOH, an administrative department with responsibility for food, radiological protection and other functions. These hygienic standards specify coating requirements for food containers, except GB 16359-1996, which is for radioactive luminescent paint. Of all the standards by MOH, GB 4805-1994, GB 9680-1988, GB 9682-1988, GB 9686-1988, GB 11676-1989, GB 11677-1989 and GB 16359-1996 are in the process of revision.

The most influential standards are GB 18581-2009 and GB18582-2008. The first versions of both were issued in 2001, when China first issued 10 compulsory standards limiting harmful substances of indoor decorating and refurbishing materials, including solvent-based wood coatings, interior architectural coatings, adhesives, furniture, wallpaper, carpet, etc., to protect the environment and safeguard human health. These standards have caused extensive attention and made tremendous contributions to the advancement of technology and the promotion of greener coatings. Based on the standards review results, SAC/TC5 started the revision of GB 18582 in 2006. The revised version, with higher technical requirements, was issued in 2008 and numbered GB18582-2008.²³ The revision of GB 18581 followed, and then the development of a series of compulsory standards limiting harmful substances in water-based wood coatings, exterior architectural coatings, coatings for toys, automotive coatings, etc. Because of its greater realistic control and the environmental significance of solvent-based wood coatings, GB 18581-2001 played a historic role in compulsory standards of coatings in China, and was awarded “The National Standard of Excellence Award” by the Standardization Administration of PRC.

  GB 50325, developed by MOHURD, is also important because it was the first standard for indoor environmental pollution control in China, which was first promulgated in 2001 and aims to control the indoor environmental pollution of civil building engineering.²⁴ Coatings are one of six types of building materials controlled by the standard (others include inorganic building materials, wood-based panels, adhesives and water-based treatment agents).

For harmful substances, a compulsory standard that specifies the requirements for anti-corrosion coatings for building steel construction structures is under development and is expected to be completed in 2012. The draft standard shows that it focuses on the limitation of VOCs, solvents under restriction and heavy metals.

In addition, GB/T 23994-2009 (limit of certain harmful elements of coatings for consumer products in contact with humans) is a standard relating to harmful substances.²⁵ It is applicable to various types of coatings used in stationery, sports equipment, household appliances, mobile phones, machine tools, bicycles and motorcycles. It is a voluntary standard at present (“/T” means voluntary standard). GB 28374-2012 (fireproof coatings for electric cable) and GB 28375-2012 (fireproof coatings for concrete structures), which are developed by technical committees SAC/TC113, were issued on May 11, 2012, and will take effect on September 1, 2012.

Technical Requirements

The compulsory coatings standards listed in Table 1 have different technical requirements. Because woodenware coatings (including some toy coatings) and architectural coatings have a more intimate relationship with our daily lives, they gain much wider attention. This article focuses primarily on the technical requirements of the coatings standards, and the limitation of harmful substances.

 The technical requirements of these compulsory standards are listed in Table 2 (see Appendix). Solvent-based coatings have similar technical requirements, so do water-based coatings. Free TDI+HDI content is only for polyurethane coatings. Free formaldehyde content is for water-based coatings, and the limit is ≤100 mg/kg for most of them. The technical requirements of GB 50325-2010 are lower than those of GB18581-2009 and GB18582-2008, as the former is a comprehensive standard on building materials and the latter two are professional standards on specified coatings.

 VOCs, such as benzene, toluene, ethylbenzene and xylene, are general controlled items for solvent-based coatings. VOCs, which have an initial boiling point less than or equal to 250 °C measured at a standard atmospheric pressure of 101.3 kPa, are dangerous to human health or cause harm to the environment. The limit differs from one coating to another, due to their different content and concentration in different coatings formulations. Benzene is considered a highly carcinogenic substance and is unlikely to be used as a raw material in coatings formulations, but since it can be an impurity in other solvents and materials, it is restricted. The toxicities of toluene, ethylbenzene and xylene are less than that of benzene, but they are also harmful to humans and their usage is controlled.²⁶ Because these items have been controlled since 2001, there are now zero-VOC coatings and benzene-, toluene-, ethylbenzene- and xylene-free coatings in the China market.

 Heavy metals are controlled in these standards, except for GB 50325-2010. Heavy metals mainly come from pigments and can do harm to the human hematopoietic and nervous systems, and are terribly cumulative. The control of heavy metals began with GB 18581-2001 and GB 18582-2001. SAC/TC5 conducted intensive research on related international standards/regulations, such as EN71-3 and ASTM F963 before developing these standards. For this reason, the technical requirements for heavy metals are considered to be advanced.

Other harmful or hazardous substances like PAHs and APEOs have also been proven toxic to humans²⁷ and have been under restriction in developed countries like the United States and Germany. They are expected to be limited in compulsory standards in China in future revised standards.

For technical requirements, testing methods including sampling are of importance along with the limit index. Every standards file explains testing methods item by item. Some items in different standards are tested in the same way, such as heavy metals in GB 18581-2009 and GB 18582-2008. Some are not, such as VOC content in the above two mentioned standards. The SAC/TC5 has made efforts to build a set of relatively complete standard testing methods for harmful substances in coatings, as shown in Table 3 (see Appendix).^28-36

Conclusion

In China, developing compulsory coatings standards is a good way to promote the advancement of coatings technology. Likewise, innovation and technology advancement will promote the development of coatings standards.

 Coatings companies entering China have to consider applying these compulsory standards. If possible, international coatings companies are encouraged to participate in drafting GB standards.

The Chinese government and market encourage coatings with higher quality. With the high growth of China’s economy and improvement of  living standards, harmful substances controlled in compulsory standards will have more stringent limits. It is worthwhile for safeguarding human health and protecting the environment. 

For more information, e-mail Xia Lin at  linx@carpoly.com.

References

¹     GB 18582-2008. (2008) Indoor decorating and refurbishing materials - Limit of harmful substances of interior architectural coatings (in Chinese).

²     GB 18581-2009. (2009) Indoor decorating and refurbishing materials - Limit of harmful substances of solvent based coatings for woodenware (in Chinese).

³     GB 24408-2009. (2009) Limit of harmful substances of exterior wall coatings (in Chinese).

⁴     GB 24409-2009. (2009) Limit of harmful substances of automobile coatings (in Chinese).

⁵     GB 24410-2009. (2009) Indoor decorating and refurbishing materials - Limit of harmful substances of water-based woodenware coatings (in Chinese).

⁶     GB 24613-2009. (2009) Limit of harmful substances of coatings for toys (in Chinese).

⁷     GB 5369-2008. (2008) General specification for drinking water tank coating of shipbuilding (in Chinese).

⁸     GB 21177-2007. (2007) Safety code for inspection of hazardous properties for dangerous goods of paint (in Chinese).

⁹     GB 19457-2009. (2009) Safety code for inspection of packaging of dangerous goods for paint (in Chinese).

¹⁰    GB 12441-2005. (2005) Finishing fire-retardant paint (in Chinese).

¹¹    GB 14907-2002. (2002) Fire-resistive coating for steel structure (in Chinese).

¹²    GB 50325-2010. (2010) Code for indoor environmental pollution control of civil building engineering (in Chinese).

¹³    GB 4805-1994. (1994) Hygienic standard for epoxy phenolic resin coating for the internal lacquer of food cans (in Chinese).

¹⁴    GB 9682-1988. (1988) Hygienic standard for internal coating of food cans (in Chinese).

¹⁵    GB 9686-1988. (1988) Hygienic standard for polyamide epoxy resin used as internal coating of food container (in Chinese).

¹⁶    GB 11678-1989. (1989) Hygienic standard for polytetrafluorethylene used as inner coating of food containers (in Chinese).

¹⁷    GB 11677-1989. (1989) Hygienic standard for water soluble epoxy internal coatings of beverage cans (in Chinese).

¹⁸    GB 11676-1989. (1989) Hygienic standard of anticoherent silicone paint for food container (in Chinese).

¹⁹    GB 9680-1988. (1988) Hygienic standard of phenol lacquer for food container (in Chinese).

²⁰    GB 16359-1996. (1996) Radiological protection standard for radioactive luminescent paint (in Chinese).

²¹    GB 7105-1986. (1986) The sanitary specifications of perchloravinyl interior coatings for food container (in Chinese).

²²    JC 1066-2008. (2008) Limit of harmful substances of building waterproof coatings (in Chinese).

²³    Peng, J. Reading and countermeasure to Chinese mandatory national standards for architectural interior and exterior wall coatings, Shanghai Coatings, vol. 49 no. 7 Sep. 2011, pp.37-44 (in Chinese).

²⁴    Bai, Z.; Wang, Z.; Zhu, Ta., et al. Developing indoor air quality related standards in China, Journal of Asian Architecture and Building Engineering, vol. 2 no. 1 May 2003, pp.55-60

²⁵    GB/T 23994-2009. (2009) Limit of certain harmful elements of coatings for consumer products contacting with human body (in Chinese).

²⁶    Zhao, L. Introduction of the national standard titled indoor decorating and refurbishing materials - Limit of harmful substances of solvent based coatings for woodenware, China Standardization, May 2003, pp.72-74 (in Chinese).

²⁷    Du, J.; Lai, H.; Li, W. Analysis of coatings product harmful material set limit standards, Modern Paints & Finishing, vol. 1 no. 9 Sep. 2011, pp.36-40 (in Chinese).

²⁸    GB/T 18446-2009. (2009) Binders for paints and varnishes - Determination of monomeric diisocyanates in isocyanate resins (in Chinese).

²⁹    GB/T 23984-2009. (2009) Paints and varnishes - Determination of the volatile organic compound content of low-VOC emulsion paints (in-can VOC) (in Chinese).

³⁰    GB/T 23985-2009. (2009) Paints and varnishes - Determination of volatile organic compound (VOC) content - Difference method (in Chinese).

³¹    GB/T 23986-2009. (2009) Paints and varnishes - Determination of volatile organic compound (VOC) content - Gas-chromatographic method (in Chinese).

³²    GB/T 23990-2009. (2009) Determination of the contents of benzene, toluene, ethylbenzene and xylene in coatings by gas chromatography (in Chinese).

³³    GB/T 23991-2009. (2009) Determination of soluble harmful elements content of coatings (in Chinese).

³⁴    GB/T 25267-2010. (2010) Determination of DDT in coatings (in Chinese).

³⁵    GB/T 23993-2009. (2009) Determination of formaldehyde content of waterborne coatings- Spectrophotometric method with acetylacetone (in Chinese).

³⁶    GB/T 23992-2009. (2009) Determination of chlorhydrocarbon content in coatings - Gas chromatographic method (in Chinese).