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    Home > Coatings News > Paints and Coatings Market > Acrylic polymer coated with pigments

    Acrylic polymer coated with pigments

    • Last Update: 2021-01-01
    • Source: Internet
    • Author: User
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    For sustainable wall coatings for better durability
    exterior exterior appearance is an extremely important parameter for most buildings around the world. Beautiful facades are often synound for strong, well-built, durable buildings. One of the advantages of high-performance exterior coatings is their beautiful appearance with high durability. In order to maintain a good appearance, exterior coatings must have good weather resistance, as well as resistance to contamination from natural or man-made dirt attacks. Although each ingredient in the formulation has an effect on the final performance of the coating, the performance and service life of the dry film is determined by the performance of the polymer. In this article, we examine how formulator designers can achieve superior environmentally friendly exterior coatings by choosing the right polymers.
    durability of pure acrylic technology
    currently, thin-layered exterior brick and stone paint uses different polymer technologies. Its choices take into account both economic considerations, performance, historical habits, and so on.
    in Europe, styrene-acrylic resin systems are the most widely used in masonry paint, although they are prone to powdering due to ultraviolet degradation of aromatic styrene monoliths (see Figure 1). In some countries, there are also co-polymer systems of ethylene carbonate; silicate coatings are often used to repair historic buildings. Pure acrylic polymers are often the first choice for high-performance coatings, and their proven durability is proven to be a leading technology not only for masonry substrates, but also for the protection of wood structures.
    acrylic technology has improved UV resistance and reduces the occurrence of powdering, although good performance with acrylic coatings depends largely on the composition of the polymer and the coating formulation.
    properties of the coating depend on the composition of the polymer, however other properties of the resin polymer, such as crosslinking, oxidation, UV curing, specific forms, etc., can improve overall performance and improve the coating's stain resistance.
    -coated pigment coating technology (PET)
    acrylic polymers covered with inormeric pigments are technology developed by the Dow Coatings Materials Business Unit. The ability of inorganic pigment particles to evenly distribute in organic phases has been a goal that coating formulators have been pursuing for many years to improve coating performance.
    of the
    the parameters that determine the scattering rate are mainly two: the difference in refractive index (the higher the better) and the particle size. According to Mi's theory, the optimal particle size of particles is half the wavelength of visible light (400 to 800nm), i.e. 300nm.
    for optimal scattering rates, titanium dioxide (with a very high refractive index) should have a particle size of 300nm and TiO2 particles must be fully separated from each other. The minimum distance between titanium dioxide particles is called the scattering range.
    Unfortunately, in water-based coatings, titanium dioxide (TiO2) particles tend to gather when the concentration of titanium dioxide increases, so that their masking efficiency is lower than theoretically expected (see Figure 2).
    in most cases, the distribution of TiO2 in the paint film is random because there is no power to arrange pigment particles in an orderly manner or separate them from each other. This results in high and low concentrations of TiO2 particle regions, which can be explained by the electron microscope image of the actual coating film (see Figure 3a). When TiO2 particles come together, their light scattering areas overlap, reducing masking efficiency (see Figure 3a).
    pigment clad polymer chemistry
    a new polymer with Dow-patented pigment coating technology that can be used as both a base material and a cover supplement. This technique improves the distribution of titanium dioxide particles and reduces aggregation, which can be explained by the distribution of particles actually coated in Figure 3b. This improvement in particle distribution has led to an increase in the light scattering rate, and if people choose to reduce the amount of TiO2 to obtain the same cover force, the use of TiO2 in high-quality white and color decorative coatings can be reduced by 10% to 20%.
    coating technology is a film-forming polymer specifically designed to interact with the surface of titanium dioxide particles. During coating production, the polymer is surrounded and reacts with a single TiO2 particle by a series of adsorptions. As more and more polymer particles are adsorbed, the polymer on the surface of TiO2 becomes saturated. The result is a pigment-polymer composite system, which can be illustrated by computer simulations and images of electron microscopes as shown in Figure 4. The optimal titanium dioxide-polymer composite system has been calculated to require the minimum amount of adsorption polymer in the formulation, and we have determined that the ratio of adsorbed polymers to TiO2 dosing is 1.35. Adding more polymers than the minimum dosing will not cause problems and may even improve the performance of the paint film, which we'll explain later.
    when the coating film is dry, pigment-polymer complexes come together to form a film, and individual TiO2 particles no longer come into close contact with each other because they are separated by the adsorption polymers around them. This structure promotes a more even distribution of TiO2 particles, reducing the area where light scattering overlaps, as described in Figure 5.
    1: The characteristics of masonry paint using pigment cladding technology and non-clading technology areCoatings10% reduction inTiO2 dosing 15% reduction in TiO2 dosing 20% reduction in TiO2 dosing all PET (polyethylene benzoate), TiO2 dosing did not decrease polymers traditional acrylic coatings Acrylic/PET coatings traditional acrylic/PET coatings traditional acrylic/PET coatings PET TiO2 PVC concentration% % 13.6 12.2 11.6 10.9 13.6
    。 Ropaque ™ (Le Pai cool™) polymer, PVC concentration, % 9.6 9.6 9.6 9.6 9.6 CaCO3 PVC concentration, % 14.4 15.1 15.4 15.4 15.8 14.4 PVC concentration, % 7.2 7.5 7.7 7.9 7.2 PVC concentration of mica quartz, % 7.2 7.5 7.7 7.9 7.2 total PVC concentration, % 52 52 52 52 52 solid content volume, % 40 40 40 40 40 40 ratio, % (100 micron wet film thickness) 93.5 - 93.5 - 94.7
    as shown in Figure 6, When measuring the function of the light scattering rate and the volume concentration of the pigment of titanium dioxide in the coating film (red line), the polymer based on pigment cladding technology can reduce the overlap of the TiO2 light scattering area, thus improving tiO2's masking force curve.
    Improve Durability
    The greatest advantage of using pigment cladding technology is that it increases the cover force or reduces the amount of titanium dioxide, while another advantage of uniform paint film is that it improves the durability of the coating.
    series of exterior brick and stone paints were prepared to study the effect of pigment coating technology on coating durability. The reference coating is a pure acrylic polymer (Tg is about 6 degrees C) with a total PVC concentration of 52% and a pigment volume concentration of about 14% of titanium dioxide.
    three formulations were re-made with pure acrylic polymers with Tg-like cladding technology compared to reference polymers. The TiO2 dosing of these three formulations was reduced by 10%, 15% and 20%, respectively, and replaced by various fillers of the same proportion (see Table 1). To understand the effects of pigment coating technology (PET) on opacity and durability results, the amount of opaque polymers in all formulations remains constant. As a result, the three newly made coatings contain two self-containing acrylic polymers: one of the substations is a pigment coating technology (PET) polymer, and the other is a traditional non-absorbent pigment polymer. Pet polymers are used in sufficient quantities to coat titanium dioxide, and the addition of non-adsorbent polymers keeps the total pigment volume concentration at 52%.
    The last coating uses adsorbent polymers as the only polymer (excessive polymer based on pigment cladding technology) and no reduction in the amount of titanium dioxide;
    five coatings on aluminum plates and sunbathed them at the Istanbul test site. The site is located near a steel plant in the harbour and is therefore able to quickly test the coating's contamination resistance (mainly industrial pollutants). We measured the change in the whiteness of the coating after 4 to 9 months of exposure to the south of 45 degrees, and the change in the coating (Delta L) was reported in Figure 7, and it is clear from the figure that pigment coating technology has a positive effect on coating resistance (the lower the L, the less contaminants the adsorption, that is, the coating remains white).
    8 shows the status of these white coatings coated on fiber-reinforced cement slabs eight months after they were exposed to 45 degrees south of Istanbul. The coating on the far left without pigment coating technology (PET) polymers appears greyer, apparently because of the adsorption of more dust.
    Compared to coatings made with only Tg-like adsorption polymers (PET), TiO2 of the same dosing, and filler preparation (after 9 months, the reference coatings of self-forming film acrylic polymers have a higher dirt adsorption (9 months later, l-15.8). This improvement in performance is due to a more uniform surface of the PET polymer coating, which reduces the rough surface that accumulates dirt and leads to faster adsorption of contaminants (see Figure 3b).
    -coated titanium dioxide improves the uniformity of dispersion, improves the durability of the exterior paint film, and the coating has excellent stain resistance and color preservation, which we will explain next.
    studied another series of masonry paints by comparing the reference coating of a self-contained film pure acrylic polymer with a Tg-like pure acrylic pigment coating technology (PET) polymer with a 15% reduction in titanium dioxide dosage. Both coatings are colored with organic indistin pigments and coated on aluminum plates.
    In order to test accelerated durability, the model is placed in the Q-UV box for 2000 hours and subjected to the following cycle test: 4 hours of UV-A (340 nm) exposure at 60 degrees C, followed by 4 hours of condensation at 50 degrees C, which is a cycle. The difference between the original color and the color obtained after a certain amount of exposure is used in Figure 9 as a reference coating and PET formula coating, by measuring the values of L, a, b, and E for different exposure times.
    the reference coatings of traditional acrylic polymers show significant color changes, especially between 1000 and 2000 hours of exposure, which is increased from 1.7 to 1.7. Coatings made with acrylic polymers capable of coating pigments have better color stability, and between 1000 and 2000 hours of exposure, the value of E is increased from 1.5 to 1.8.
    of the coating of traditional self-made film acrylic polymers can be explained by the powdering caused by the degradation of the surface of the lacquer film. On the other hand, coatings with PET acrylic polymers can result in a coating with better durability due to a more uniform and complete paint film.
    coating technology can also improve the weathering resistance of the coating. Due to the optimal distribution of mineral particles in the organic phase, the cohesion of the paint film is improved, and this new adsorption technology also promotes the adhesion between the paint film and the masonry substrate, providing excellent weathering resistance for the final coating. This advantage was observed in the actual outdoor exposure when coating early pigment clad technical coatings on fiber-reinforced cement slabs, as shown in Figure 10.
    Life Cycle Assessment - Environmental Impact Costs
    A life cycle assessment (LCA) comparison of water-based coatings to understand the possible environmental impact of pigment coating technology. The purpose of the evaluation (LCA) is to objectively evaluate the environmental properties of water-based decorative coatings produced using the above pigment cladding technology and many existing traditional polymer technologies (e.g. acrylic, styrene/acrylic, ethylene acetate, ethylene acetate/ethylene acetate), and to compare the results to help us understand some facts.
    LCA assessment in accordance with international standards (ISO 14040 and ISO 14044). Third-party reviews by PwC Global Sustainability Services (PWC) and peer reviews by selected LCA and industry experts
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