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    Home > Coatings News > Paints and Coatings Market > The formula optimization method of zero VOC multi-function additive formulation is adopted

    The formula optimization method of zero VOC multi-function additive formulation is adopted

    • Last Update: 2021-01-01
    • Source: Internet
    • Author: User
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    Increasingly stringent environmental regulations, such as lower volatile organic compound (VOC) levels, are forcing paint manufacturers to change the way they produce coatings. VOC regulations are caused by its reaction to nitrogen oxides (NOx) in the air during sunlight, producing trophic ozone, commonly known as photochemical fumes, which can have serious health effects on those affected areas. To address this problem, the U.S. Federal Clean Air Act (40 C.F.R.) aims to control air pollution at the national level. The law is regulated by the U.S. Environmental Protection Agency (EPA), state and local governments.
    while raw material suppliers have developed many new and innovative products to meet these low VOC requirements, maintaining coating performance at lower VOC content is a challenge. 2-amino-2-methyl-1-propylene alcohol, commonly known as AMP
    ®
    , is a versatile additive used in the coatings industry. In June 2014, the U.S. Environmental Protection Agency exempted AMP as a VOC-exempt compound due to its low reactivity to nitrogen oxides in the atmosphere and low toxicity.
    AMP has been effectively used as a low odor mesostizer, its versatile properties have not been fully utilized. This article explains how AMP can be used to optimize low VOC formulations in low VOC coatings.
    molecules
    AMP is an amino alcohol obtained by propane nitrification. Structurally, it is beetamine, which is directly connected to the uncle carbon atom, so there is no hydrogen to take on the adjacent α carbon (Figure 1). This is important for two main reasons. First, it excludes oxidation degradation in ultraviolet light, which means that AMP will not cause yellowing of the coating. Second, it excludes the possibility of ozone forming in the surface atmosphere.
    of these and other mesodes
    table 1 illustrates the main differences between several typical mesodrants used in AMP and the coatings industry. Monoethanolamine (MEA) is beetamine, while N-butyl dinosamine (NBDEA) is seramine. Structurally, both molecules contain seizable hydrogen in α carbon atoms bonded to the amine. This leads to film yellowing and high reactiveness to the atmosphere, which promotes ozone formation.
    efficiency is also an important feature to consider. The meso-agent has higher efficiency when it has a higher pKa and a lower molecular weight. Compared with NBDEA, AMP has both a high pKa value and a lower molecular weight. Compared with ethanolamine, the value of AMP is closer. In addition, the boiling point of ethanolamine is similar to that of AMP. This suggests that both are similar in efficiency and volatility rates. Third, the structural differences between the two amines are significant: ethanolamine causes membrane yellowing and produces surface ozone, where as well as AMP does not. NBDEA, on the other hand, has much lower pKa and higher molecular weight, resulting in a significant reduction in its efficiency. The NBDEA also has a much higher boiling point, which remains in the coating film. This plasticizer effect often results in poor adhesion resistance and poor coating properties, such as poor water resistance, cleanliness and scrub resistance. Ammonia and sodium hydroxide are inorganic alkalis and are not VOCs by definition, but each has a problem. For example, when consumers use ammonia, there are production problems and unwanted odors due to the strong smell of ammonia. Sodium hydroxide, although there is no odor problem, is highly corrosive, difficult to handle and retains in the dry film, thereby reducing the performance of the dry film.
    multifunction additive
    in the grinding process using dispersants such as polysic acids to replace the air/moisture on the pigment surface, so that the tightly clustered pigments are separated. By making pigment particles resistant to flocculation, the dispersant reduces the viscosity of the dispersion, thus increasing the amount of pigment. The result is increased viscosity stability, opacity, coloring, gloss, and anti-sinking. Static receding force and spatial bit resistance are two main processes used to stabilize dispersion and prevent flocculation.
    electrostasitic rejection or charge stabilization (Figure 2), polyalic dispersants are adsorbed to the pigment surface, allowing their charge to be transferred to pigment particles. This results in a negative charge on the surface of the pigment particles. Collectal theory describes electrostectrical stability as a double electron layer. In this case, an electric charge is generated on the pigment surface, and the ions with the opposite charge are surrounding it. When similar charged particles are close to each other, the charge repulsion forces make them mutually exclusive. The thickness of the double layer increases the stability of the particles.
    space stability requires polymers to be adsorbed to the pigment surface. Co-property with carboxy acid groups is an effective space stabilizer because they provide a strong interaction energy by providing charge on the nirch on most particle surfaces. The other end of the molecule remains in the water phase and is tangled with other chains as particles and attempts to get close to each other, creating a barrier that prevents flocculation.
    it is not enough to fully understand how AMP is used as a co-dispersant.
    there may be multiple mechanisms at work here. During the grinding phase, amp is used as part of a dispersant combination, and the amine base is adsorbed to the pigment surface, increasing the likelyity of the double layer. Compared with other dispersants,
    because AMP has a much lower molecular weight, it may also improve the wetting of the pigment surface area area, resulting in increased charge stability and spatial stability.
    inorder pigment surface has a surface charge, depending on the pH of the system. Each pigment has an isoelectration point (pH) at which point the surface charge is zero. When the pH adjusts away from isoelectrelect points, the charge becomes unbalanced. This increased charge leads to an increase in rebuke. The particle surface AMP adsorption is improved and the charge is enhanced, thus improving the dispersion stability.
    formula optimization approach
    amp has been the standard midramp for the industry for many years. Paint formulating designers usually use it during the paint phase to achieve the desired pH range. In some cases, partial AMP is added during the grinding phase to activate THE AND cellulose thickeners. The full benefits of using multi-functional AMP are rarely fully recognized. As discussed earlier, it is an excellent co-dispersant. Proper understanding and use of AMP provides a formulation solution for optimizing the entire coating formulation. So, how do you determine how many AMPs are added during the grinding phase? This can be achieved by mapping the dispersant demand curve for specific pigment compositions used in coating formulations.
    3 shows a typical dispersant demand curve. Mix pigments with a small amount of water (enough to make a thick slurry) in a laboratory mixer. The dispersant is titred in lower increments in the mixture and mixed and stirred over a set period of time to determine the viscosity value of Brookfield. The resulting data is plotted into a curve of the percentage content of the viscosity to the dispersant. As the amount of dispersant increases, the viscosity decreases. Balance at the lowest viscosity, which represents the demand for dispersants. Gradient studies are needed to evaluate AMP as a co-dispersant. Add amp to the initial/watery slurry and titrate with the dispersant described earlier. The data then plot out a curve with only dispersants. As you can see in Figure 3, by adding AMP, the viscosity decreases and the curve shifts to the left, which means that less dispersants are used. From these data, optimized abrasive slurry can be obtained with lower viscosity and lower dispersant dosage. During the paint phase of the coating, AMP can be added to adjust the final pH of the coating.
    of dispersed doses can lead to other potential formulation optimizations, including reduced additions to surfactants and desiccants. Because coating formulations vary widely and are complex, each case needs to be considered on a case-by-case basis. The result of optimization can be seen throughout the life cycle of the coating: production, in tanks, coating and dry film (on the wall).
    conclusion
    zero VOC additives could pave the way for a greener future and create healthier alternatives to traditional coatings with high volatile organic compound content.
    AMP is a very good neutralizer with very strong versatility. In order to fully understand the potential of formulation optimization, formulators need to evaluate AMP as a co-dispersant during the grinding phase. As a fully volatile volatile, the EPA still treats it as an exempt VOC member that does not plasticize the dry film, thereby improving adhesion resistance and other dry film properties such as water resistance, scrub resistance, and cleanliness. In addition to improving in-tank stability, AMP also improves coating stability during drying. When the coating is dry, reducing flocculation improves optical properties such as gloss and cover. AMP offers safer handling and lower odor alternatives than other inorganic alkalis such as ammonia and sodium hydroxide, while providing significantly better versatility.
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