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    Home > Coatings News > Paints and Coatings Market > A new anti-light agent is used in low-gloss UV curing coatings

    A new anti-light agent is used in low-gloss UV curing coatings

    • Last Update: 2021-01-01
    • Source: Internet
    • Author: User
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    Over the past few decades, significant progress has been made in detergents or additives used to improve surface roughness, based on a variety of sources, including the connection of basic polymer types to silicon dioxide-based additives. This paper focuses on silica-based anti-light dispensers based on seboding or gel processes, which are specific to UV-cured coatings. These coatings face the challenge of requiring low-gloss surfaces because they are generally solvent-free, have little paint film shrinkage, and the line speed and curing volume are constantly changing.
    Special amoeba synthetic silica combined with specific polydimethylsiloxane surface treatments improves the efficiency of light dissipation, and this new product, designed for low-light, high-transparency, low-viscosity systems, is designed for UV-cured coatings. Compare the new anti-
    #4
    technology
    (
    MA4
    ) with those available on the market.
    The experimental discussion
    lighting agent study
    First we will list the physical
    /
    chemical properties of the anti-lighting agents included in this study, and then review the formula used and some data related to performance. The test values include the de-lighting efficiency and increased viscosity at
    60
    degrees and
    85
    degrees, which are the main considerations for UV-cured coatings, especially in areas where low-light surfaces are
    60
    degrees
    10
    ). Other results related to transparency, surface smoothness and morphological differences are also listed, which are technically assessed by scanning the paint film electroscopy.
    1
    1
    compared the physical and chemical data of the light-eliminating agent studied. These anti-light agents vary in particle size,
    pH
    , morphology and treatment type. Compared with other existing technologies, the main innovation of the anti-lighting agent
    #4
    (
    MA#4
    ) is the new reactive sioxane treatment with acrylic nerds, which improves the compatibility of UV-cured coating systems.
    and additions
    all anti-lighting agents are added in different amounts to achieve a
    60
    degree angle gloss of
    15
    . Once the gloss level is fixed, the de-lighting efficiency, viscosity increase and transparency can be assessed. Table 2
    the
    used in this study is given.
    to achieve the required gloss range, the amount of addition changes within the eight levels used in the test, from a minimum of
    7.8 g
    to a maximum of
    23.2 g
    . When the gloss level drops from
    25
    to
    15

    at an angle of
    60
    degrees, the anti-light
    #3
    shows a high viscosity increase. The higher the viscosity of the formula, the more construction problems will be faced, which will be discussed later in this article when scanning the electroscope analysis. Figure
    1
    the difference in the amount of detergent added to achieve the target gloss range.
    transparency
    the transparency of the formula itself is related to the amount added to the detergent, but also to the type of treatment. Figure
    2
    visual comparison of test grades is given. It should be noted that the system uses a new
    #4
    high transparency after de-lighting. This high transparency is directly related to the treatment of sioxane in the new acrylic errands, and the amount required to achieve the target gloss is low. Figure
    3
    's UV
    -
    visible light transmission curve comparison also proves this, even if the
    12.8 g
    anti-light agent is added to achieve the desired gloss range, the light-transmission curve has barely decreased, and its shape is almost identical to the UV curing coating system without detergent.
    the

    4
    and Figure
    5
    are listed in four different film thicknesses
    20
    ,
    40
    ,
    60
    and
    80
    μ
    m
    hours
    60
    degrees and
    85
    degrees ad.m. gloss data. Apply the paint with a wire rod to
    byK
    's control card
    no.2854
    sheet. The efficiency of the UV-cured coating system depends on several factors, and the physical/
    /
    properties of the anti-light agent itself are affected. Average particle size and surface treatment also play an important role. The selection of trigger, the reaction activity level of lysate and the speed of curing line are also the key factors that affect the lighting of UV curing coating system.
    light-
    is added and dispersed after the light-trigger is added. They can also be premixed with monosomes first. In general, it is not recommended to add dispersants because they reduce the efficiency of de-lighting.
    usually fast line speed and high reaction activity of lymers can lead to higher gloss. Slower line speed, better orientation, coupled with the use of low-reactive lymer will improve the efficiency of light dissipate. In this system, we use two different triggers from
    BASF
    , which utilize their different sensitivity to wavelengths,
    Irgacure
    ®
    184
    for shorter wavelengths, while
    Irgacure
    ®
    819
    (commonly used for colored coatings) is suitable for longer wavelengths. In light-down coatings,
    Irgacure
    ®
    819
    has a beneficial effect on the curing process of thicker coatings. This results in higher coating shrinkage, which improves the de-light efficiency (low light). These trigger combinations are usually recommended for thicker coatings.
    is distinguished from other types of coatings, an interesting trend in UV-cured coatings is when the film thickness increases and the zest decreases. The higher the film thickness in the UV-cured coating system, the higher the shrinkage effect of the coating film. For low gloss, the goal is to achieve maximum volumetric shrinkage and the highest filling density of the anti-light agent. Compared with other technologies, for ultraviolet curing coating system, coating film shrinkage has certain limitations, we found that the finer the anti-light agent, the more effectively reduce the thick film
    60
    degrees angle gloss.
    A key factor in
    's increased viscosity is the effect on the increased viscosity of the UV-cured coating system, which may be due in part to the need to add a higher amount of detergent to reduce gloss to very matte levels. The greater the viscosity increase, the adverse effect on the construction and overall appearance. Figure
    6
    the performance of the eight products tested. The new anti-light agent
    MA4
    has been shown to have minimal impact, with a viscosity close to Newtonian after a very low shear rate
    1s-1
    , at
    10-1000 s-1
    .
    the transparency of
    film
    the transparency results of the curing coating film can be found in figures
    7-9
    . For different film thicknesses (
    20
    ,
    40
    ,
    60
    ,
    80
    and
    120
    μ
    m

    2
    0
    ) were compared with different gloss ranges (
    15
    and
    60

    ) at
    60
    . To assess transparency, coatings were applied at different thicknesses on
    MA
    ) plates. Place these transparent paint plates (tested with eight anti-light dissipants) on black-and-white control card paper. The transparency is assessed by the image density meter. In both cases, the transparency on the black-and-white contrast card paper was tested, and the higher the value, the higher the transparency. (For those unfamiliar with such tests, the difference that the human eye can usually recognize is
    0.1
    .) As expected, when the film thickness increases, the transparency decreases. However, for some grades of anti-lighting agents, the difference is very small, while others are very obvious. With the new anti-
    , the
    of ma
    maintains a good level of transparency. In the example, the
    ma
    shows the best performance at
    20-80
    μ
    m
    thickness. This is also not the result of a phase, because this grade of anti-light agent to achieve the target
    60
    degrees angle gloss of
    15
    need to add a higher amount of anti-light agent. Using
    ma#7
    , significantly less transparency is found at higher film thicknesses.
    Surface Roughness
    10-12
    10-12
    surface roughness performance. Figure
    10
    surface roughness (surface profile) is measured using a contact surface photon.
    roughness is measured with a contact photon, which can be used to describe the surface appearance of the coating. During the measurement, the tip of the needle on the diamond (
    2
    ) slides over the substrate (work piece) (
    5
    ) at a constant speed (
    3
    ). The measured profile (
    6
    ) is generated by the vertical position drift on the tip of the diamond (
    4
    ), which usually converts the signal into an electrical signal. Therefore, the standard roughness parameters can be measured by this electrical signal to describe the surface. Based on this measurement, the resulting roughness values are reported as
    Ra
    and
    Rz
    .
    Ra
    is an arithmetic average of the roughness values obtained by measuring the absolute values of all contours in the section.
    Rz
    indicates the distance between the highest peak and the lowest groove. Together, these two values describe the roughness values, indicating whether there are some or many peaks (high roughness) and the depth of the peaks (whether they are shallow or deep grooves). The technical definitions of these values
    in
    11.
    results are summarized in Figure
    12
    , and the new
    MA4
    provides a balance between high de-lighting efficiency and minimum roughness (low
    Ra
    and
    Rz
    values), indicating that the surface is highly smooth while having considerable transparency.
    microscopic analysis
    microscopic photogram (Figure
    13
    ) shows the differences in the forms of light-emitting agents and particle distributions of the various levels included in this study. Scanning electroscope analysis shows that the current UV-cured coating anti-light technology, will produce more angles and irregular shapes, particle size distribution range is wide. Some bubbles can be easily found on the cross-sections of some UV-cured coatings that are de-glazed with the anti-light technology
    MA#6
    due to the high viscosity of the formula to reach the desired gloss level.
    Conclusion
    Overall, the new reactive sioxane treatment of sedimentation silicon dioxide technology (expressed in
    MA#4
    ) provides a new option for UV curing coating formulator designers to achieve a low-light appearance while maintaining low construction viscosity and high transparency for a highly smooth surface.
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