Green paint is the future direction of the industry, but the development path is not smooth.

What is green paint?
there is no
global consensus on the concept of
green coats", which often leads to confusion when the term is used across national borders or on a global scale. However, more and more projects and product specifications, specifications are international, different specifications of products purchased globally, materials and labor from all over the world. China's standards are many different from those of the United States or the European Union, while some countries do not even have standards, some countries borrow existing standards from other countries or industry organizations to legislate and revise them to their own standards, and some countries restrict the use of many paint varieties in some parts of their interior.
's restricted coatings are most commonly based on their volatile organic compound (VOCs) content, however, the method of calculating VOCs content for each coating differs significantly from country to country, with some using theoretical values and some using actual values, which often vary widely.
building decoration coatings are already subject to stricter regulations and more stringent government and regulatory restrictions around the world, so many products are already within the concept of "green coatings".
, however, can functional protective coatings, such as 100,000 coatings commonly used on metal or concrete surfaces, be reduced to "green coatings"?
most common indicator of whether a coating is "green" is VOCs, which are measured in g/L. How is this value calculated? The reality is that each batch of coatings of the same variety has different VOCs levels; When paint products use pigment coloring, liquid slurry also typically adds VOCs to coatings, sometimes up to 15%. These conditions further complicate the problem of VOCs, which can be measured in the laboratory or theoretically - but often with relatively low calculations.
challenge for chemists to measure or calculate VOCs by different standards. Most global coating manufacturers are required to publish VOCs values for their products in their product data sheets or region-specific standards.
most commonly used standards are as follows
EU SED (Solvent Emissions Directive) 1999/13/EC -
Marine Coatings
and OEM projects, paint users may also be subject to annual VOCs emission limits.
EU PPD (Coatings Products Directive) 2004/42/EC (including various updates) - for smaller projects such as patching paints and
building coatings
- This method considers organic compounds with a boiling point greater than 250 degrees C (482 degrees F) as VOCs.
Hong Kong has adopted rules similar to those in California's South Coast Air Quality Management Zone (SCAQMD) and is working with Guangdong Chinese mainland to reduce VOCs emissions. However, Hong Kong now uses EPA method 24 (EPAMethod24) "Measurement of volatile substance content, water content, density, volume solids and mass solids in surface coatings" to calculate volatile organic compounds. China, on the other hand, followed (but did not strictly implement) EU guidelines until February 2015, when the Ministry of Finance passed the VOCs consumption tax, which measures VOCs in construction status based on EPAMethod24.
EPAMethod24 is the only method currently accepted by the EPA and U.S. state/local regulators to measure VOCs in
paint
, ink and related coating products. However, some studies have suggested that this method is known and has been shown to have a large measurement error, especially for VOCs below 50g/L coatings. At present, it is found that the main source of VOCs error is water and non-volatile substance determination. Because of this level of error, the industry is currently looking for methods of measuring VOCs directly by gas chromatography (GC), such as ASTMD6886 and SCAQMD method 313.
Korea is currently taking VOCs control measures to control the relatively high VOCs content of its paint products under its Air Quality Protection Act, with the goal of reducing the perefa margin by 10 to 20 per cent from the current maximum threshold. EPAMethod24 is also the country's main and most commonly used method for calculating VOCs and harmful air pollutants (HAPs).
can be seen that consistency and commonality are not generally recognized in these standards for VOCs measurement. Why? Although they all measure solvents that turn into steam, the mathematical formula for each method allows for different exemption ranges, different fluctuations, and variances, resulting in different values that should have been the same. Some of the factors that cause the calculation method to conflict include: theoretical and actual VOCs content, mathematical calculation and experimental testing and extraterrion methods, and whether to exclude or compensate water, specific solvents or container volumes. The establishment of a globally consistent VOCs calculation method standard can lead to an agreement on the understanding of the "green" characteristics of coatings.
other green indicators
even if the coating has low VOCs levels, it can still be harmful to the environment or human body. Several other factors may affect the "green" characteristics of coatings, including HAP, ozone-depleting chemicals, banned chemicals, exempt solvents and heavy metals.
1, HAPs
. HAP is a chemical in VOC that is particularly harmful to health and/or the environment. HAP is regulated in many countries, especially after the United States Congress amended the Federal Clean Air Act in 1990 to single out a number of air pollutants that are known to cause or may reasonably be expected to adversely affect human health or the environment. Initially, nearly 200 specific contaminant and chemical groups were identified as HAP and the list was established to change over time. Common HAPs include xylene, styrene, and toluene. Although methyl ethyl ketone (MEK) was originally on the list, it was removed by the EPA in 2005 at the request of the American Chemical Commission. HAPs are usually listed separately from VOCs and are considered the second common indicator of the "green" degree of coatings.
2, ozone-depleting chemicals
When certain hydrocarbon solvents evaporate from the coating, they are decomposed, often referred to as photochemically reactive solvents or simple reactive solvents. Photochemical reactions are measures of how much compounds react in the atmosphere and contribute to ozone formation. The most common photochemically reactive solvents are toluene and xylene. SCAQMD defines photochemical reactive solvents as "any solvent containing more than 20% of the total volume of the following classified compounds, or a single percentage (relative to the total volume of the solvent) that exceeds the limits of any of the following classified compounds."
★ of hydrocarbons, alcohols, aldehydes, esters, ethers or ketones with olefins or cyclic olefins unsaturated: 5%;
★ in addition to ethyl benzene, the composition of aromatic compounds with 8 or more carbon atoms in the molecule: 8%;
★ combination of ethyl benzene, ketones with branch-chain hydrocarbon structures, triclosan or toluene: 20%.
in addition to photochemically reactive solvents, other solvents are also known as non-photochemical reactive or non-reactive solvents. Acetone is classified as a negligible reactive solvent, meaning it has no effect on the deterioration of the ozone layer. MEK is classified as a low-reactive solvent, which means that it has little effect on ozone depletion. Coatings containing non-photochemically reactive solvents are generally considered more environmentally friendly than coatings containing photochemically reactive solvents, but still pose health, safety and environmental (HSE) risks.