Effect of dispersant structure and dosage on the performance of latex paint (2)
Last Update: 2021-01-21
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1 shows that of the 3 dispersants selected, the S110 preparation coating has the smallest color difference and the best water resistance before and after immersion under the premise of the same dosage. This is because the dispersant S110 has a benzene ring structure relative to dispersants A and B, so that its prepared coating film shows excellent water resistance. In addition, Figure 1 shows that the amount of dispersant is also very closely related to the water resistance of the coating. This is because the amount of dispersant increased, pigment dispersion efficiency also increased, pigment particles become smaller, so that the flatness of the film increased, the gap between the particles become smaller, so after the film coating unblistered part and soaked part of the color difference is small, water resistance improved. However, when the amount of dispersant is greater than 7, the color difference between the unblistered part and the soaked part of the color intensity increases, because when the dispersant dosage is too much, the wetting of the coating film is increased, resulting in a decrease in the water resistance of the coating, therefore, the amount of dispersant added in the coating should be between 5 and 7.
effect of 3.2 dispersants on coating cover is
Figure 2 shows the effect of dispersant structure and dosage on coating cover.
As can be seen from Figure 2, when the amount of addition increases from 3 to 11 inches, the covering power of the coating increases. As mentioned earlier, the increase in dispersant dosage is conducive to improving the dispersion efficiency of pigments, so that the particle size of pigments is reduced, the particle size distribution range is narrower, and the covering force is enhanced. In addition, comparing the masking performance of the preparation coating under the same amount of dispersant addition, it is found that when the amount of dispersant addition is less than 5, the masking force corresponding to S110 is worse than that of dispersants A and B, but when the amount of dispersant is greater than 5 inches, the masking force corresponding to S110 has a slight advantage over dispersants A and B. This may be because when the dispersant dosage is less than 5, dispersant A, B to inorgeable pigment dispersion efficiency is higher than S110, cover force than S110 has an advantage, and when the dispersant dosage is greater than 5 per cent, due to the increase in dispersant use, dispersant A, B dispersion inorge pigment viscosity is too low, dispersion efficiency is not high, so S110 corresponding to the cover force is slightly better than dispersant A, B slightly advantage.
3.3 Effect of dispersants on paint color display
Select large red, indistinct blue, carbon black, iron red 4 kinds of market common color paste, the amount of addition of color paste is 2% latex paint, coloring strength to dispersant A as the standard (the amount of addition is 5 inches, color intensity is 100%).
As can be obtained from Figure 3, in the selected 4 color pastes, with the increase of dispersant dosage, color intensity increased, paint color display improved. And the S110 has the best color performance among 3 dispersants. This is because the increase in dispersant dosage can continuously reduce the flocculation of color pigment particles, thus improving color display. At the same time, due to relative to the other two dispersants, the S110 dispersant contains a benzene ring structure, similar to the organic pigment structure, so that the dispersant and pigment particles adsorption more closely, pigment particle size distribution range is narrower, the lowest degree of flocculation, the best color display.
3.4 Effect of dispersants on coating stability
Choose dispersants A, dispersants B, S110, dispersant dosage selection 7, prepare latex paint 1, 2, 3 respectively. To study the effect of dispersant type on paint stability, the specific test method can be seen in the stability test in the test scheme.
As can be seen from Table 2, at room temperature for 3 months, latex paint 1 storage stability is poor, there is a slight water-split phenomenon, and latex paint 2, latex paint 3 storage status is good. After the latex paint is hot-stored or frozen, latex paint 1 has a serious water dispensing phenomenon, latex paint 2 has a slight water dispensing phenomenon, and latex paint 3 has not seen abnormal phenomenon. From the above 3 different storage states can be found that in 3 dispersants, S110 prepared the highest stability of the coating, mainly because S110 is a modified segment co-property, and dispersants A and B are acrylic and modified polycarbonate dispersants, can not provide an effective spatial level resistance effect, the stability of the system mainly depends on the double layer effect, when the double layer is damaged by external factors, the stability of the coating system will be significantly reduced.
This paper discusses the effect of dispersant on the water resistance, color spread and stability of the preparation of latex paint, and the results show that the paint has the best water resistance when the amount of dispersant is between 5 and 7. At the same time elected with the insertion copolymer dispersant S110, because S110 its own structure has hydrophobic benzene ring structure, organic pigments have a good dispersion effect, prepared paint water resistance, color display of color paste, sedimentation stability are significantly better than the commercially available dispersants A and B, coating cover than dispersants A and B slightly advantages.
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