Study on the application of cobalt blue pigment in latex paint on the outer wall.

Cobalian blue pigment in the outer wall latex paint application research
Zeng Hui Chong, Wang Naidi, Tao Wei, Fu Yan, Zhang Anjie
(Northwest Yongxin Coatings Co., Ltd., Lanzhou 730046)relative to organic pigments, inorganic pigment cover high, with good chemical stability and thermal stability, cobalt blue as the representative of inorganic environmental pigments have attracted much attention. At present, more inorganic blue pigments are used in iron blue, group blue and cobalt blue. Among them, iron blue is not resistant to alkali, group blue is not acid-resistant, so it is basically replaced by organic blue pigment indiplasty, indistinct blue and cobalt blue pigment compared with the advantages of strong coloration, high color saturation, but its heat resistance, weather resistance, light resistance is not good. In the outer wall latex paint, color adjustment is mainly complex color, light bright mainly, too bright color easy to stain, the outer wall brush area is larger, the coating exposure to the atmosphere by many weather and environmental factors, from the long-term effect, coloring pigment light resistance, aging resistance plays a key role. Cobalt blue pigment as an important inorganical environmental pigment, compared with other blue pigments in light resistance, anti-aging performance has an important advantage, will be widely used in such environments, become irreplaceable products.main component of cobalt blue pigment is cobalt alumina, chemically CoAl2O4, with a density of 3.8 to 4.5 g/cm3, which belongs to the cubic crystals crystals of the crystallization of the sharps. Pigment index number: C. I. Pigment Blue 28 (C. I. PB28). The appearance of blue powder, has a bright color, with excellent weather resistance, acid and alkaline resistance, belongs to non-toxic environmental pigments. Can be used in glass, ceramics, enamel, high temperature-resistant engineering plastics and high-temperature weather-resistant coatings. At present, the research on cobalt blue pigments mainly focuses on the preparation method of high-performance cobalt blue pigments and the effect of doping with other metal elements on pigment color performance. The research on the application performance of cobalt blue pigments is also mainly focused on plastics and ceramics, while the application of coatings is rarely reported. In this paper, two kinds of imported and domestic commercially available cobalt blue pigments were selected, the differences in the chemical and chemical properties of 2 pigments were studied, and the application results of water-based slurry and outer wall latex paint were examined, thus providing experimental basis for the application of cobalt blue pigments in coatings.1 Experimental Part
1. 1 Main Raw Materials
Advanced Pure C Exterior Latex Paint (TT, 1/1ST, 1/25ST): Northwest Yongxin Coatings Co., Ltd.; Cobalt Blue Pigment (I.): Domestic; Cobalt Blue Pigment (II.): Imported; Bao Wet rheumogenic agent, pH regulator: Dow; Dispersant (BYK187), desiccant: Foamex 810, Digo TEGO; Dust inhibitor (BYK420): BYK; Anti-mold fungicide: Dow; Indigo Blue Pulp: Guangzhou Cody New Materials Technology Co., Ltd.. 1. 2 Major instruments
X-ray diffraction meter; ESCALAB 250 XRD, Thermo, UNITED States; transmission electron microscope: JEM-1200EX/STEM, Japan Electronics Corporation; infrared spectrometer: NEXUS 470FT-IR, Thermo Corporation of the United States; Laser particle size: LS603, Zhuhai Europe and the United States Instrument Co., Ltd.; Chroma meter: HP-2132, Shanghai Han spectrum photoelectrelectrometer Co., Ltd.; Aeselectral spectroscopicity Instrument: CIE (XRite, Ci 7800), Alyssa, USA; X-ray energy spectrometer: EDS2100, Beijing Chinese Science and Technology Development Co., Ltd.; High-speed dispersion machine: BGD740, Guangzhou Standard Gerda Laboratory Instrument Supplies Co., Ltd.; 1/1 000 Electronic Balance: JA2003, Shanghai Precision Instrumentation Co., Ltd.; Scraper fine meter: 0 to 50 m, Tianjin Second Material Test Machine Factory; Wet Film Preparer: U-Type 200 sm, Tianjin Water Resources Laboratory Equipment Co., Ltd.; Viscosity meter: STM-V, Shanghai Modern Environmental Engineering Technology Co., Ltd.; Wire rod coater: XB type, Shanghai Modern Environmental Engineering Technology Co., Ltd.. 1. 3 Preparation of cobalt blue water-based paint slurry
the preparation of water-based paint slurry in accordance with the formulation quantity in Table 1, said to take a certain amount of deionized water, moisturizing rheumate, a small amount of de-foaming agent 500 r// min stir 15 min, fully stirred premixed and evenly, at a high speed of 2 500 r/min stirring to add pigments and other additives to disperse, and then after grinding, filtration, that is, preparation to obtain cobalt blue water-based slurry products.. 1. 4 Preparation of colored outer wall latex paint
cobalized outer wall latex paint (I.), cobalt blue (II.) water-based paint slurry according to 5% of the total quality of latex paint, at 500 to 600 r/min speed added to the advanced pure propylene outer wall latex paint, prepared colored outer wall latex paint (I., II.).. 1. 5 Performance test methods and standards
in accordance with the HG/T 3951-2007 "building paint water-based color paste" standards set out in the relevant requirements to test the basic performance of water-based paint slurry, with chroma meter to determine the color value, and evaluate its relative coloring force, the use of Stommer viscosity meter to test viscosity, with scraper fineness meter to determine fineness.
compatible test method: using finger research method to test the compatible of color paste and outer wall latex paint, the colored latex paint coated on black and white paper jam, to be coated to half-dry, with the index finger on the coating film for a circle grinding table Layer part, test the basic performance of latex paint according to GB/T 9755-2014 Synthetic Resin Emulsion Exterior Paint, use wet film preparation to prepare latex paint black and white cardboard, test latex paint coloring force, use visual Color method to test the color difference of latex paint, according to GB/T 23987-2009 "color paint and varnish coating artificial climate aging exposure to fluorescent ultraviolet rays and water" standard method A artificial accelerated aging test, UVA340 lamp , the sun: rainfall: 1:1, the test temperature is 60 degrees C, the rainfall temperature is 50 degrees C, the relative humidity during rainfall is 100%, according to GB/T 1766-2008 "coating aging rating method" rating.2 Results and discussion
2. 1 The symptoms of cobalt blue pigments
2. 1. 1 EDS and TEM diagrams of two cobalt blue pigments
The hue and color intensity of inorganic metal oxide blend pigments depend mainly on the content of hair-colored metal ions and the electron state of the metal ions with their formed mating field. Cobalt blue pigment color is produced because the lattic co (II) coloring ions are mixed, Al, O colorless, used to balance the price, Co (II) is hair color ions, therefore, the higher the content of Co (II), the stronger the pigment tone and color intensity. Therefore, cobalt blue (CoAl2O4) pigment cobalt, aluminum content and ratio on pigment color performance, color performance has a great impact. Figure 1 shows the EDS and TEM comparison of the two cobalt blue pigments.
Figure 1 shows that cobalt blue pigments I. and II. are composed of C, O, Al, Co4 elements, wherein pigment I. contains a small amount of calcium, cobalt content is lower than II. Theoretical analysis, pigment I. hair color intensity and coloring force should be lower than pigment II. As can be known from Figure 1, the initial particle size of cobalt blue pigment (I.) is large and the reunification is serious.. 2. 1. The structure, crystallization type and purity of 2 cobalt blue pigments XRD and FT-IR spectrographs
pigments have a significant impact on the colorability and resistance of pigments. The molecular structure and crystallization properties of cobalt blue pigments can be analyzed by infrared spectrometers and X-ray diffraction meters. Figure 2 is an XRD and FT-IR spectrogram of two cobalt blue pigments.
can be seen from Figure 2 (a), CoAl2O4 feature peaks appear at 668 cm-1, 557 cm-1 and 509 cm-1, both cobalt blues are not doped and organically modified. As can be seen from Figure 2 (b) in the range of 20 to 80 degrees, against the standard diffraction card CoAl2O4-JCPD card No. 10-458, in the range of 2 degrees to 31. 1 degree, 36. 8 degrees, 44. 8 degrees, 49. 0, 55. 5 degrees, 59. 2 degrees, 65. (220), (311), (400), (331), (422), (511) and (440) wafers of CoAl2O4, respectively. The crystal diffraction peak position of the two cobalt blue pigments basically re-fits, and belongs to the CoAl2O4 crystal of the typical sharpstone structure, and the crystallization purity is high and the grain is perfect.. 2. 1. 3 Cobalt blue pigment color value and particle size distribution
CIE standard established a set of color-coded color space system, is the international standard for color measurement. It is suitable for the display and calculation of all light source colors or object colors, the color of any object can be expressed in CIE-L*a*b*color weight value, L*for brightness, numerical range (0 to 100); To the green range, b s represents the range from yellow to blue, the value fields are (-127 to -128), and in polar coordinates, the test data contains C, H, where H is the tonal angle, and C is the saturation. As a result, the chromic values of the two cobalt blue pigments can be compared by using the color weight values of L, a, b, C, and H.The brightness, saturation and hue of the two cobalt blue pigments are basically close from the L, C and H values, but the cobalt blue pigment (I.) b-value is higher, and the cobalt blue pigment (II.) is lower than the (I.) blue value, slightly biased towards the green phase. As a whole, the two cobalt blue pigments show a bright blue color. According to the calculation method of CIE1976 (L*a*b*), the color difference of the surface pigment is calculated to be 3. 49。
the particle size and distribution of the two cobalt blue pigment particles were tested with a laser particle size meter, and the test results were shown in Figure 3.
as can be seen from Figure 3, cobalt blue (II.) pigment particle size is all less than 2. 5 sm, and its particle size is generally smaller than cobalt blue (I.) particle size. In addition, the size distribution of the two pigments is narrow, and the particle size distribution is mainly at 0. Between 5 and 2 sm. It is explained that after crushing treatment, the particles are dispersed evenly, which is more conducive to the preparation of slurry and improve the coloration and stability of latex paint. . 2. 2 kinds of cobalt blue water-based paint slurry performance
according to table l formulation of cobalt blue (I.), cobalt blue (II.) water-based paint slurry, in accordance with HG/T3951-2007 "building paint water-based slurry" standard, testing two cobalt blue water-based paint plasma basic physification indicators and coloring performance, the results can be seen in Table 3, Table 4. . Note: Chroma E data is a relative value, the test generally specified a better performance sample as a standard sample, test other samples and its chroma. Table 4 "Label" represents the standard sample tested as can be known from Table 3, both cobalt blue pigments are prepared with a slurry fineness of 10 m, and both slurry particle sizes are 5 m and below, Cobalt blue (II.) slurry is superior to (I.) in particle size, consistent with its pigment particle size test results, which indicates that the smaller the initial particle size of the pigment under the same conditions, the smaller the favor of wetting and dispersion, the greater the viscosity of the dispersed color paste. In addition, both cobalt blue pigments have excellent acid and alkaline resistance.
After parallel test testing, cobalt blue (II.) pigments with the same solid content have a higher coloring force, combined with the color slurry particle size test results, elemental analysis results show that the higher the cobalt blue pigment hair color ion Co2 plus content, the smaller the initial particle size, the narrower the distribution, after stable dispersion of the coloring force is stronger. Select the coloring force of the higher (II.) color paste with 1/1ST, 1/25ST advanced pure C external wall latex paint diluted as the specimen, test (I.) colored latex paint 1/1ST, 1/25ST and the specimen relative coloring force and color difference values. The results show that with the increase of dilution multiplication, the difference of color difference decreases gradually, that is, latex paint with high titanium content can reduce the difference in color paste and reduce the color difference of color, but the coloring force difference is not much. . 2. 3 2 color slurry and outer wall latex paint compatible test
in accordance with the experimental part 1. 5 compatible test method, test the compatibness of two cobalt blue pulp and advanced pure propylene outer wall latex paint (1/25ST). The results of the experiment are shown in Figure 4. the compatible between the color paste and the use system is the key to affect latex paint floating hair flower, flocculation and some paint film surface defects. Before using color paste color matching, it is necessary to do compatible test, as can be seen from Figure 4, after doing, observe the wipe part and the unwabbed part without color difference, floating color, flowering. It shows that the pigment dispersion is stable, the color paste prepared is better compatible with the test coating, the latex paint of the outer wall is colored with the color paste, the color coating obtained, the surface of the preparation model paint film is free of defects, and the test paint film resistance index is reliable. . 2. 4 Colored exterior latex paint basic performance test
with water-based paint slurry accounted for 5% of the total quality of latex paint (1/25ST) prepared colored outer wall latex paint (I., II.) in accordance with GB/T 9755-2014 "synthetic resin emulsion outer wall paint" standard requirements for the preparation of samples, basic performance test results as shown in Table 5. can be known from Table 5, blue outer wall latex paint (I.), (II.) all performance indicators have reached GB/T 9755-2014 standard requirements of superior products. The test results of the ratio show that the blue outer wall latex paint (II.) cover substrate is balanced, compared with the blue outer wall latex paint (I.) cover performance is more excellent. This is mainly due to the small particle size of pigments, larger than the surface area, the light refraction and scattering effect is strong, improve the ability to cover. In addition, I., II. blue outer wall latex paint alkaline resistance, artificial climate aging performance is excellent, 600 h non-foaming, non-peeling, no cracks, color change less than or equal to 1 level. . 2. 5 Colored outer wall latex paint artificial accelerated aging test comparison
with cobalt blue (II.) color paste and commercially available indistinct blue slurry for high-grade pure propylene latex paint (1/25ST) respectively to color, modulation of the same depth, plate maintenance after artificial accelerated aging test, compared with the color difference and yellow color resistance of indistinct and cobalt blue coloring of the outer wall paint. Gb/T 23987-2009 color paint.