"China Paint Online News Information" With the widespread application of real stone paint, real stone paint easy to produce color difference and cause flowering, yellow change, poor resistance to dirt, paint film whitening and other ills are gradually emerging, including the color difference caused by light hair flowers affect beauty, heavy need to rework re-painting, causing serious economic losses, is the real stone paint in practice is facing the most common and the most difficult problem.
True stone paint color differences are due to a variety of reasons, color sand batch stability (natural sand is difficult to achieve the same color between batches), substrate treatment (different substrate color and porosity may lead to different colors of real stone paint), construction conditions (different environmental factors such as temperature, humidity and wind speed during construction and maintenance may lead to color Different), construction methods (differences in construction habits of different construction personnel and scaffolding or basket construction and other differences may lead to different film thickness, surface floating sand or slurry caused by differences in surface texture caused by color differences; uneven hood light caused by different gloss resulting from color differences) and many other aspects may produce color differences and thus cause flowering problems. For these many factors caused by flowering problems can only be specific analysis of the cause of color difference in each case in order to find a corresponding solution to the problem.
True stone paint temperature change color difference
true stone paint in a variety of color difference flower phenomenon is more common and difficult to deal with a color difference flower is temperature color difference, that is, the same batch of real stone paint on the same wall by the same construction personnel in accordance with the correct construction procedures, but because of the wall temperature and ambient temperature different and lead to different colors of the phenomenon. For example: the same day morning, noon and afternoon construction of the same real stone paint to get different colors;
usually low-cost dark real stone paint is most prone to temperature variance, such as brown, brick red, dark gray and other colors. The change law of temperature change color difference of real stone paint is usually the darker the temperature, the lower the temperature the lighter the color, as shown in Figure 1 for a brand of real stone paint TH, at 35 degrees C (right) conservation color is much darker than 10 degrees C (left) color, showing a very serious phenomenon of temperature change. This law of change is very similar to such as ordinary latex paint, ordinary latex paint when PVC is close to or greater than CPVC is also prone to the phenomenon of temperature variance, Figure 2 for the same external wall latex paint construction at different temperatures to get different colors, and the higher the temperature the darker the color, the lower the temperature the lighter the color.
True stone paint is usually built on site, wall temperature and ambient temperature can not remain the same during the construction period, at the turn of the season day and night temperature difference may sometimes be as high as 30 degrees C, and wall temperature difference may be greater. We can't and don't have to ask for real stone paint to be constructed at constant temperatures. As shown in Figure 3, a brand of high-quality real stone paint TX is maintained at 10 degrees C and 35 degrees C respectively, and the final color is almost identical. By some visible, it is completely able to solve the temperature variance problem of real stone paint by optimizing the formula of real stone paint.
The effect of true stone paint formulation on temperature variance
True stone paint is mainly composed of emulsion, color sand, additives (film additives, thickeners, etc.), so this paper discusses the effect of true stone paint formula on temperature variance from these aspects.
experimental method: in the experiment, each formula is made of liver red sand into real stone paint, with 1mm thick film template scraping film, in the relative humidity is 50%, the temperature is 5, 10, 23, 35 degrees C under the maintenance of 7 days, visual comparison of dry film color The depth, and according to the 0-10 score (true stone paint film color is not uniform, should not use grading photomeometer to measure the score), 10 points of the darkest color, 0 points of the lightest color, the higher the score indicates the better the quality of the film, the lower the score indicates the worse the quality of the film. The closer the final rating of the true stone paint of the same formula to maintenance at different temperatures indicates that the smaller the temperature variance, the better the performance.
from the above real stone paint temperature variance analysis shows that the amount of emulsion on the paint film porosity rate has a great impact, may lead to temperature change color difference. Table 1 is a review of the color of the lacquer film at different temperatures with 8%, 10%, 12% and 15% of the four real stone paints, respectively.
Summary Table 1 scoring data can be seen the following laws:
1, the higher the emulsion content, the darker the color of the real stone paint, the smaller the temperature change difference; The greater the difference,
2, the same formula, the higher the temperature, the darker the color, the lower the temperature, the lighter the color,
3, different emulsion content of the real stone paint at high temperature conservation chroma difference is relatively small, but at low temperature conservation when the color difference is larger.
is the most important component in real stone paint in addition to emulsion, the cost of real stone paint, performance impact is second only to emulsion. The fineness, absorption rate and hardness of colored sand may have an effect on the temperature variance. Table 2 is the result of four true stone paints with different color sand grades and different color evaluation results of the lacquer film at different temperatures.
analysis table 2 score shows that the finer the color sand at the same lotion dosage, the lighter the color at the same temperature, and the greater the temperature variability at different temperatures. Comparing formulas 2 and 6, it can be known that it is more likely to change temperature difference when the grade of sand is the same.
Comparing the data in Tables 1 and 2 shows that the fineness of the colored sand may have a greater effect on the temperature variance, because the fineness of the colored sand not only affects the pore rate but also affects the size of the pores, and ultimately improves the efficiency of light scattering from two aspects to produce a stronger chromic difference.
In recent years due to vicious competition, a small number of enterprises in order to reduce costs, reduce the use of higher prices of colored sand in real stone paint, often use fine colored sand (such as 200 color sand) or even color paste to color is one of the main reasons for the frequent problem of temperature variance. High-quality real stone paint should use 40-80 eyes and 80-120 purposes of color sand mainly to tone, if there is a need, the use of finer color sand to tone, should be correspondingly increased the amount of emulsion to reduce the occurrence of temperature variance.
the same reason, the absorption rate and hardness of colored sand used in real stone paint are also very important indicators, which must be strictly controlled. The high water absorption rate of colored sand is often due to the large amount of fine ash, which directly leads to increased pore rate and produces a temperature variance. Colored sands with low hardness are usually highly absorbent and may increase the likely chromation difference during the production process due to further fracking due to grinding.
sintered colored sand and dyed colored sand can reduce the consumption of emulsion to a certain extent due to the low absorption rate of less ash, so it can reduce the occurrence of temperature variance.
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