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    Home > Coatings News > Paints and Coatings Market > Water-based paint "performance indicators" full!

    Water-based paint "performance indicators" full!

    • Last Update: 2021-01-12
    • Source: Internet
    • Author: User
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    Water-based paint "performance index
    the surface performance of water-based paint: the surface performance refers to the general can be more intuitive to feel, such as its leveling, flow resistance, dryness, sanding, color accuracy and other performance.
    performance of water-based paint: the evaluation of intrinsic performance is an important index to determine the quality of water-based paint.
    1. Viscosity index: the degree of polymerization of paint material and the use of additives can be observed by viscosity

    . Viscosity varies greatly with temperature, so sometimes the viscosity varies greatly during the winter and summer rainy seasons.
    test method: after 20 minutes of product sampling, adjust the paint sample temperature (winter 15 degrees C, summer 25 degrees C), test with Iwata 2 cups, the next day with the same method to test again.
    2. Solid content: This indicator refers to the content of active ingredients in the coating.
    detection method: T -160 degrees C (detection 2 hours), paint sample weight of 3-5 grams, pay attention to even spread paint sample.
    3. Hardness: Hardness is divided into 6H, 5H, 4H, 3H, 2H, H, F, HB, 2B, 3B, 4B, 5B, 6B, etc. 14 grades, ordinary paint film hardness is generally between B-3H, paint film hardness is only a simple indicator of grading film performance.
    test method: according to GB /T6739 regulations, pencil for the Chinese brand 101 drawing pencil test.
    hardness of water-specific paint single-part products about HB, two-group product hardness of about 1H.
    4. Adhesion: Adhesion is an important sign of the degree of closeness between water-based paint and substrate, and also a sign of whether water-based paint will fall during the long-term use of furniture.
    5. Gloss:
    detection method: black glass scraper film thickness of 250 microns, 45 degrees C baking for 2 hours, first calibration of the meter, and then test the product. The first production of the product should be based on the effect of the spray plate.
    6. Anti-adhesion: the
    stacks six plates (150mmx70mm) from top to bottom, in order: one face up, two faces down, one face up, two faces down. Ensure two face-to-face contact, two back-to-back contact, in the sample plate to apply a diameter of about 70mm, the mass of 500g weight.
    drying conditions: 20 minutes at room temperature 25 degrees C - 30 degrees C table, then 70 degrees C dry for 4 hours, and finally 25 degrees C - 30 degrees C cooling for 60 minutes, placed in a 50 degrees C oven for 4 hours, After removing the pressure to separate the model, check the degree of difficulty of separation and the degree of damage to the surface of the coating film (visible traces), the results of the judgment in the form of "adhesion grade" and "surface damage level" two forms, each form according to different degrees are divided into six levels, as follows.
    adhesion grade is divided into surface damage levels
    A-Free-fall separation 0-no damage
    B-slight tap-separation 1-<1% damage
    C-separation after applying a slight pull 2-1%-5% damage
    D-separation after applying medium pull 3-6% - 20% damage
    E - Separation of damage after applying a great pull force 4 to 21% to 50%
    Fineness: Fineness is the standard for checking the size or dispersion of pigment particles in water-based paint, expressed in microns (sm). The smaller the finer the film, the smoother it is, and the rougher it is.
    detection method: when the dispersion time is sufficient, take the appropriate amount of product with scraper fineness meter scraping, in ten seconds to read out the fine data.
    8. Impact resistance: it is also an important index of the flexibility of the paint film. The significance of this index to metal paint is particularly obvious, the better the resistance, then the more difficult the paint film in the impact conditions appear white, off-layer phenomenon.
    9. Cold resistance: refers to the ability of paint film to resist cold under low temperature conditions. This performance is a prerequisite for determining whether furniture Chinese mainland use in cold winter areas such as the northern part of the country.
    10. Heat resistance: The passing of this performance is to ensure that the paint film in general use conditions for hot water, teapots and other daily necessities of the heat requirements.
    9. Temperature resistance: This indicator is a higher level of paint film requirements. Only paint film that can withstand the hot and cold cycle test can obtain the basic conditions for safe use in any climate.
    :
    10. Yellow resistance: is the paint film in the use of color preservation performance of the indicators, generally using UV light or before and after the sun color difference, to quantify the degree of color change. The smaller the color difference, the better the color preservation, and the better the design of the paint film under the test conditions should have a small color difference.
    water-based paint "painting guide
    water-based paint in the use of problems and solutions:
    1, water-based paint peeling off: may be the surface is too smooth, if the original paint is light paint or powder (plus untreated slurry paint), the new water-based paint on the surface will not stick. Or it may be wood decay or rust spots, but also due to poor quality water-resistant paint peeling. Small area of water-resistant paint peeling, can be polished with fine yarn paper, painted with primer, and then repainted. Large areas of shedding must be all polished and re-sprayed.
    2, paint film wrinkled: thick coated water-color paint film at high temperature, paint film surface quickly dried into a film but the inner layer is dry slowly, in the drying process the flow of paint produces a difference in tens of pressure, resulting in the final film surface uneven, that is, wrinkle.
    the construction of the coating to take a thin coating many times, to ensure that the coating evenly dried into a film, to achieve the paint film flat effect.
    3, paint film adhesion difference: part of the water-like wood paint construction, will find that the coating layer between the bonding is not secure, resulting in poor attachment phenomenon, the emergence of layers and layers between each other. The direct cause is that when the water-like paint is constructed, there is no polishing or poor polishing between the layers. Therefore, the grinding process needs to be careful, sand through the sand leakage is strictly prohibited.
    4, bubbles, needle eyes: the water in the coating film is not completely volatile, the surface has been dry, resulting in the surface is water rushed to the top, if the top is broken is the needle eye, if not broken into bubbles.
    . The wood is too humid, the construction environment temperature is high, the water in the wood after painting quickly evaporates impact paint film, the thicker the paint film, the more serious the bubbles.
    b. One-time thick coating;
    c. the upper process is not dry and begins to do the next process, the water sealed in the inner layer evaporates outwards will form bubbles.
    d. Did not use matching water-colored paint products.
    Prevention, solution:
    (1) the highest water content of wood should not exceed 15%, if necessary, the use of low-temperature drying treatment, or let the wood dry naturally and then apply, before applying primer it is best to put on a layer of solid primer, the substrate closed treatment.
    (2) cannot be applied thickly at a time;
    (3) unused water-like paint should be sealed and placed in a cool, dry and ventilated area.
    (4) when applying primer, allow it to thoroughly dry and paint.
    (5) unused water paint should be sealed and placed in a cool, dry and ventilated area.
    5, cracks appear: this situation is mostly due to the construction of temperature below 5 degrees C, construction paint film is too thick, plate quality is not good, shrinkage and other reasons. Because the paint coating is too thick, the surface is dried into the film too fast, while the inner layer is dry slowly, resulting in the bottom cracking and other phenomena.
    solution:
    (1) to ensure that the construction temperature should be above 5 degrees C,
    (2) pay attention to thin coating, to ensure that the paint film thickness is moderate,
    (3) select good quality plate, to ensure stability.
    6, hanging phenomenon:
    a. White blank surface uneven, complex geometry;
    b. Spray gun and workware is too close;
    c. too much spray at a time, thick coating, spray interval is short.
    d. Viscosity is too thin and volatile too slow.
    e. Construction environment temperature is too low;
    prevention and treatment methods:
    (1) white blank table treatment level, complex geometry of the work to be sprayed multiple times;
    (2) spray gun and workware to maintain a distance of 20-30CM;
    (3) to reduce air pressure, control the amount of oil, quantity;
    (4) reduce the number of thinners, construction viscosity should be about 90-120 seconds (2 cups);
    (5) spray coating should be in the first layer of paint film after the basic table dry and then spray a second time;
    7, paint film whitening: paint film whitening mainly because the construction environment humidity is too large, the construction process coating film is too thick caused, in rainy days or humidity in the weather, agreed to produce a layer of whitening. Therefore, in the construction process, pay attention to the table dry time and do-it-it time.
    8, orange peel, wrinkles: the coating film is not fully leveled is dry.
    a. Paint is too thick;
    b. pressure is too high, the nozzle is too close to or too far away from the work piece;
    c. thinner type is not available;
    d. Ambient temperature is too high;
    prevention, solution:
    (1) to the construction viscosity (2 cup) 90-120 seconds or so;
    (2) reduce air pressure, spray and work parts to maintain the distance between 20-30CM, paint film do not spray too thin;
    (3) thinner type to be used in support of the selection of appropriate slow-drying solvents;
    (4) adjust the temperature of the spray room, control the exhaust flow.
    9, bite bottom, loss of light whitening:
    a. Upper and lower layers of paint do not match, inter-layer time is too short to spray;
    b. temperature is too low spray room humidity is too high, poor ventilation environment caused the paint film whitening loss of luster;
    prevention, solution:
    (1) upper and lower layers of coating supporting use, inter-layer construction time extended to dry and sprayed a second time.
    (2) the construction temperature is controlled at about 25 degrees C, the humidity is about 40%-60%,
    (3) adjusts the water-like paint ratio and construction viscosity, and
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