Halogen-free high-brightness black pigment and preparation method thereof

Abstract

The invention relates to the field of pigments, in particular to a halogen-free high-brightness black pigment and a preparation method thereof.The preparation method comprises the following steps that 1, activated cobalt oxide is prepared; step 2, preparing thiolated cobalt oxide; 3, preparing surface modified cobalt oxide; and 4, preparing the halogen-free high-brightness black pigment. The prepared black pigment combines the advantages of an inorganic-organic pigment, has better dispersity and brightness compared with a conventional inorganic pigment, and not only does not contain halogen, but also has stronger light resistance compared with a conventional organic pigment.

Description

Technical Field

[0001] The invention relates to the field of pigments, and in particular to a halogen-free high-brightness black pigment and a preparation method thereof. Background Art

[0002] With the development of society, people pay more and more attention to the decoration of buildings. Homes, offices and entertainment places are decorated with a large number of architectural decorative paints, wallpapers and decorative panel lights to reflect the style. Various colors of inks are printed on the wallpaper to form decorative wallpaper.

[0003] In the production process of ink, pigments have a great influence on the ink, not only affecting the appearance of the ink, but also the printing effect of the ink. The commonly used pigments for inks include inorganic pigments and organic pigments. Inorganic pigments are relatively simple to produce, cheap, and have good mechanical strength and hiding power, but they also have problems such as dark color, not bright enough, poor dispersion, and incomplete color spectrum. Organic pigments not only have good dispersion, but also bright colors and rich types. They can produce pigments of various colors, but organic pigments are more likely to fade or change color when exposed to harsh conditions for a long time. Therefore, organic pigments often contain certain halogens. Adding halogens can play an antioxidant role, improve light stability, and reduce the risk of aging.

[0004] Although the addition of halogens to the pigments used in inks can improve the performance of inks, it can also bring about some environmental problems, such as the generation of harmful halogenated substances during the combustion process, which can cause certain pollution and harm to the environment. Therefore, in the future pigment market, the preparation and use of pigments that do not contain halogen elements will become a development trend. Summary of the invention

[0005] In view of the problems existing in the prior art, the object of the present invention is to provide a halogen-free high-brightness black pigment and a preparation method thereof.

[0006] The purpose of the present invention is achieved by adopting the following technical solutions:

[0007] In a first aspect, the present invention provides a method for preparing a halogen-free high-brightness black pigment, comprising the following steps:

[0008] Step 1: Activate the surface of cobalt oxide particles in an alkaline solution to obtain activated cobalt oxide;

[0009] Step 2, treating the activated cobalt oxide with coupling agent KH-580 to obtain thiolated cobalt oxide;

[0010] Step 3, mixing the mercaptolated cobalt oxide and 4-vinylaniline in a solvent, and reacting them under the action of a photoinitiator to obtain surface-modified cobalt oxide;

[0011] Step 4: Mix the surface-modified cobalt oxide and bisphenol A diglycidyl ether in anhydrous ethanol, and heat the mixture to react to obtain a halogen-free high-gloss black pigment.

[0012] Preferably, in the first step, the purity of the cobalt oxide particles is higher than 99% and the particle size is 10±2 μm.

[0013] Preferably, in the first step, the surface activation treatment process includes:

[0014] The cobalt oxide particles are immersed in a sodium hydroxide solution and stirred at room temperature for 2-6 hours at a stirring speed of 200-300 r / min. After the stirring is completed, the precipitate is centrifuged and washed with water until the washing liquid is neutral. After drying, activated cobalt oxide is obtained.

[0015] Preferably, in the surface activation treatment process in step 1, the mass fraction of sodium hydroxide is 10%-20%, and the mass volume ratio of cobalt oxide particles to sodium hydroxide solution is 1g:(10-20)mL.

[0016] Preferably, in the second step, the preparation process of mercaptolated cobalt oxide comprises:

[0017] The coupling agent KH-580 was dissolved in ethanol, and the activated cobalt oxide was added, and the mixture was ultrasonically homogenized, and then refluxed at 65-75°C for 6-12 hours. After the reflux, the precipitate was centrifuged, washed with water three times, and vacuum dried to obtain thiolated cobalt oxide.

[0018] Preferably, in the second step, the mass volume ratio of the activated cobalt oxide, coupling agent KH-580 and ethanol is 1 g: (0.1-0.5) g: (10-20) mL.

[0019] Preferably, in the third step, the preparation process of the surface-modified cobalt oxide comprises:

[0020] The thiolated cobalt oxide and N-methylpyrrolidone are mixed, ultrasonically dispersed evenly at room temperature, 4-vinylaniline is added, and a photoinitiator is added at the same time. The mixture is stirred under ultraviolet light for 0.8-1.6 hours. After the reaction is completed, the precipitate is collected by centrifugation, washed three times with alcohol, and then dried to obtain surface-modified cobalt oxide.

[0021] Preferably, in the third step, the mass volume ratio of thiolated cobalt oxide, 4-vinylaniline and N-methylpyrrolidone is 1 g: (0.23-0.46) g: (15-25) mL.

[0022] Preferably, in the third step, the photoinitiator is one of benzoin methyl ether (BME), benzoin ethyl ether (BEE), and benzoin butyl ether (BBE). The amount of the photoinitiator added is 3%-9% of the mass of 4-vinylaniline.

[0023] Preferably, in step 3, the intensity of the ultraviolet light is 200-300 mW / cm 2 , the wavelength is 200-400nm, preferably 365nm.

[0024] Preferably, in the fourth step, the process of temperature-raising reaction treatment comprises:

[0025] The surface modified cobalt oxide and anhydrous ethanol are mixed, ultrasonically dispersed evenly, heated to 70-80°C under the condition of a reflux condenser, bisphenol A diglycidyl ether (BADGE) is added dropwise, and after the addition is completed, the mixture is kept warm and stirred for 2-3 hours, and the precipitate is collected by centrifugation, vacuum dried, and ground through a 200-mesh sieve to obtain a halogen-free high-gloss black pigment.

[0026] Preferably, in the fourth step, the mass volume ratio of the surface-modified cobalt oxide, bisphenol A diglycidyl ether and anhydrous ethanol is 1 g: (0.57-1.14) g: (15-25) mL.

[0027] In a second aspect, the present invention provides a halogen-free high-brightness black pigment prepared by the above-mentioned preparation method.

[0028] The beneficial effects of the present invention are:

[0029] 1. The black pigment prepared by the present invention combines the advantages of inorganic and organic pigments. Compared with conventional inorganic pigments, it has better dispersibility and brightness. Compared with conventional organic pigments, it not only does not contain halogen, but also has stronger light resistance.

[0030] 2. The present invention uses black-gray hexagonal cobalt oxide powder as a basic raw material, activates and thiolates its surface in sequence to obtain thiolated cobalt oxide; then uses 4-vinylaniline to participate in the reaction to obtain cobalt oxide particles containing aniline groups on the surface; then, it undergoes an epoxy-amino bonding reaction with bisphenol A diglycidyl ether to finally obtain the desired black pigment.

[0031] 3. In the process of preparing the surface-modified cobalt oxide, the aniline group is fixed on the surface of the cobalt oxide through the thiol-ene click chemical reaction between the thiol-cobalt oxide and 4-vinylaniline, and the thioether group is also introduced; in the subsequent process, the aniline group is cross-linked with the epoxy group in bisphenol A diglycidyl ether, and the bisphenol A group is introduced. Subsequent testing found that the black pigment prepared by the present invention has good dispersibility, brightness and light resistance. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] The present invention is further described using the accompanying drawings, but the embodiments in the accompanying drawings do not constitute any limitation to the present invention. A person skilled in the art can obtain other drawings based on the following drawings without creative work.

[0033] Figure 1 is a SEM schematic diagram of the halogen-free high-gloss black pigment prepared in Example 1 of the present invention;

[0034] Figure 2 The figures are physical schematic diagrams of the black pigments of Example 1, Comparative Example 1 and Comparative Example 2 of the present invention; wherein, (a) Example 1, (b) Comparative Example 1, and (c) Comparative Example 2. DETAILED DESCRIPTION

[0035] The technical solution of the present invention is described below through specific examples. It should be understood that the one or more method steps mentioned in the present invention do not exclude the existence of other method steps before and after the combination step or the insertion of other method steps between these explicitly mentioned steps; it should also be understood that these embodiments are only used to illustrate the present invention and are not used to limit the scope of the present invention. Moreover, unless otherwise specified, the numbering of each method step is only a convenient tool for identifying each method step, and is not intended to limit the order of arrangement of each method step or to limit the scope of the present invention. The change or adjustment of the relative relationship thereof shall also be regarded as the scope of the present invention without substantially changing the technical content.

[0036] In order to better understand the above technical scheme, the exemplary embodiments of the present invention are described in more detail below. Although exemplary embodiments of the present invention are shown, it should be understood that the present invention can be implemented in various forms and should not be limited by the embodiments set forth herein. On the contrary, these embodiments are provided in order to enable a more thorough understanding of the present invention and to enable the scope of the present invention to be fully communicated to those skilled in the art.

[0037] The present invention will be further described below in conjunction with the following examples.

[0038] Example 1

[0039] A halogen-free high-gloss black pigment, the preparation method of which comprises the following steps:

[0040] Step 1: Soak cobalt oxide (CoO) particles with a purity higher than 99% and a particle size of 10±2 μm in a 15wt% sodium hydroxide solution, wherein the mass volume ratio of the cobalt oxide particles to the sodium hydroxide solution is 1 g:15 mL, and stir at room temperature for 4 hours at a stirring speed of 250 r / min. After stirring, centrifuge to obtain a precipitate, wash with water until the washing liquid is neutral, and vacuum dry to obtain activated cobalt oxide;

[0041] Step 2: Dissolve the coupling agent KH-580 in ethanol, add the activated cobalt oxide, the mass volume ratio of the activated cobalt oxide, the coupling agent KH-580 and the ethanol is 1g:0.3g:15mL, ultrasonically homogenize, and then reflux at 70°C for 9h. After the reflux, centrifuge to obtain the precipitate, wash it with water three times, and vacuum dry it to obtain the thiolated cobalt oxide;

[0042] Step 3: Mix the thiolated cobalt oxide and N-methyl pyrrolidone, and after ultrasonic dispersion at room temperature, add 4-vinyl aniline. The mass volume ratio of thiolated cobalt oxide, 4-vinyl aniline and N-methyl pyrrolidone is 1g:0.34g:20mL. At the same time, add the photoinitiator benzoin ethyl ether (BEE) in an amount of 6% of the mass of 4-vinyl aniline. Then, at a wavelength of 365nm and a light intensity of 250mW / cm 2 The mixture was stirred and treated under ultraviolet light for 1.2 hours. After the reaction was completed, the precipitate was collected by centrifugation, washed with alcohol three times, and then dried to obtain surface-modified cobalt oxide.

[0043] Step 4: Mix the surface modified cobalt oxide and anhydrous ethanol, disperse them evenly by ultrasonication, heat them to 75°C under the condition of a reflux condenser, add bisphenol A diglycidyl ether (BADGE) dropwise, the mass volume ratio of surface modified cobalt oxide, bisphenol A diglycidyl ether and anhydrous ethanol is 1g:0.86g:20mL, keep warm and stir for 2.5h after the addition is completed, collect the precipitate by centrifugation, dry it in vacuum, grind it through a 200-mesh sieve, and obtain a halogen-free high-gloss black pigment.

[0044] Example 2

[0045] A halogen-free high-gloss black pigment, the preparation method of which comprises the following steps:

[0046] Step 1: Soak cobalt oxide particles with a purity higher than 99% and a particle size of 10±2 μm in a 10wt% sodium hydroxide solution, wherein the mass volume ratio of the cobalt oxide particles to the sodium hydroxide solution is 1 g:10 mL, and stir at room temperature for 2 hours at a stirring speed of 200 r / min. After stirring, centrifuge to obtain a precipitate, wash with water until the washing liquid is neutral, and dry to obtain activated cobalt oxide;

[0047] Step 2: dissolving the coupling agent KH-580 in ethanol, adding the activated cobalt oxide, the mass volume ratio of the activated cobalt oxide, the coupling agent KH-580 and the ethanol is 1g:0.1g:10mL, ultrasonically homogenizing, and then refluxing at 65°C for 6h. After the reflux is completed, centrifuging to obtain the precipitate, washing it with water three times, and vacuum drying to obtain the thiolated cobalt oxide;

[0048] Step 3: Mix the thiolated cobalt oxide and N-methyl pyrrolidone, and after ultrasonic dispersion at room temperature, add 4-vinyl aniline. The mass volume ratio of thiolated cobalt oxide, 4-vinyl aniline and N-methyl pyrrolidone is 1 g:0.23 g:15 mL. At the same time, add the photoinitiator benzoin methyl ether (BME) in an amount of 3% of the mass of 4-vinyl aniline. Then, at a wavelength of 365 nm and a light intensity of 200 mW / cm 2 The mixture was stirred and treated under ultraviolet light for 0.8 h. After the reaction was completed, the precipitate was collected by centrifugation, washed with alcohol three times, and then dried to obtain surface-modified cobalt oxide.

[0049] Step 4: Mix the surface modified cobalt oxide and anhydrous ethanol, disperse them evenly by ultrasonication, heat them to 70°C under the condition of a reflux condenser, add bisphenol A diglycidyl ether (BADGE) dropwise, the mass volume ratio of surface modified cobalt oxide, bisphenol A diglycidyl ether and anhydrous ethanol is 1g:0.57g:15mL, keep warm and stir for 2h after the addition is completed, collect the precipitate by centrifugation, dry it in vacuum, grind it through a 200-mesh sieve, and obtain a halogen-free high-gloss black pigment.

[0050] Example 3

[0051] A halogen-free high-gloss black pigment, the preparation method of which comprises the following steps:

[0052] Step 1: Soak cobalt oxide particles with a purity higher than 99% and a particle size of 10±2 μm in a 20wt% sodium hydroxide solution, wherein the mass volume ratio of the cobalt oxide particles to the sodium hydroxide solution is 1 g:20 mL, and stir at room temperature for 6 hours at a stirring speed of 300 r / min. After stirring, centrifuge to obtain a precipitate, wash with water until the washing liquid is neutral, and dry to obtain activated cobalt oxide;

[0053] Step 2: Dissolve the coupling agent KH-580 in ethanol, add the activated cobalt oxide, the mass volume ratio of the activated cobalt oxide, the coupling agent KH-580 and the ethanol is 1g:0.5g:20mL, ultrasonically homogenize, and then reflux at 75°C for 12h. After the reflux, centrifuge to obtain the precipitate, wash it with water three times, and vacuum dry it to obtain the thiolated cobalt oxide;

[0054] Step 3: Mix the thiolated cobalt oxide and N-methyl pyrrolidone, and after ultrasonic dispersion at room temperature, add 4-vinyl aniline. The mass volume ratio of thiolated cobalt oxide, 4-vinyl aniline and N-methyl pyrrolidone is 1g:0.46g:25mL. At the same time, add the photoinitiator benzoin butyl ether (BBE) in an amount of 9% of the mass of 4-vinyl aniline. Then, at a wavelength of 365nm and a light intensity of 300mW / cm 2 The mixture was stirred and treated under ultraviolet light for 1.6 hours. After the reaction was completed, the precipitate was collected by centrifugation, washed with alcohol three times, and then dried to obtain surface-modified cobalt oxide.

[0055] Step 4: Mix the surface modified cobalt oxide and anhydrous ethanol, disperse them evenly by ultrasonication, heat them to 80°C under the condition of a reflux condenser, add bisphenol A diglycidyl ether (BADGE) dropwise, the mass volume ratio of surface modified cobalt oxide, bisphenol A diglycidyl ether and anhydrous ethanol is 1g:1.14g:25mL, keep warm and stir for 3h after the addition is completed, collect the precipitate by centrifugation, dry it in vacuum, grind it through a 200-mesh sieve, and obtain a halogen-free high-gloss black pigment.

[0056] Comparative Example 1

[0057] A black pigment, selected from the inorganic pigment cobalt black (Pigment Black 27) sold on the market.

[0058] Comparative Example 2

[0059] A black pigment, selected from the organic pigment aniline black PBK1 sold on the market.

[0060] Experimental testing

[0061] The performance of the black pigments of Example 1 and Comparative Examples 1-2 is compared. The results are shown in Table 1. The chromaticity in Table 1 is detected by a chromameter to obtain its L * a * b * value; among them, L * The value represents the brightness of the material, the higher the value, the brighter it is; a * The value represents the red-green deviation, b * The color difference △E in Table 1 represents the change in chromaticity before and after the pigment powder is irradiated with an arc lamp for 168 hours, so as to judge the light resistance. The reference standard for testing is ASTM D4303-03, and the calculation formula is △E=[(△L*) 2 +(Δa*) 2 +(Δb*) 2 ]1 / 2, the smaller the color difference value △E, the better the light resistance performance.

[0062] Table 1 Performance of different black pigments

[0063]

[0064] It can be seen from Table 1 that the black pigment prepared in Example 1 of the present invention not only does not contain halogen, but also has relatively high brightness and good light resistance.

[0065] Although the embodiments of the present invention have been shown and described above, it is to be understood that the above embodiments are exemplary and are not to be construed as limitations of the present invention. A person skilled in the art may change, modify, replace and vary the above embodiments within the scope of the present invention.

Claims

1. A method for preparing a halogen-free high-gloss black pigment, characterized in that: The following steps are involved: Step 1: Activate the surface of cobalt oxide particles in an alkaline solution to obtain activated cobalt oxide; Step 2, the cobalt oxide is activated by treating it with coupling agent KH-580 to obtain thiolated cobalt oxide; Step 3, mixing the mercaptolated cobalt oxide and 4-vinylaniline in a solvent, and reacting them under the action of a photoinitiator to obtain surface-modified cobalt oxide; Step 4: Mix the surface-modified cobalt oxide and bisphenol A diglycidyl ether in anhydrous ethanol, and heat the mixture to react to obtain a halogen-free high-gloss black pigment.

2. The method for preparing a halogen-free high-gloss black pigment according to claim 1, characterized in that: In the first step, the process of surface activation treatment includes: The cobalt oxide particles are immersed in a sodium hydroxide solution and stirred at room temperature for 2-6 hours at a stirring speed of 200-300 r / min. After the stirring is completed, the precipitate is centrifuged and washed with water until the washing liquid is neutral. After drying, activated cobalt oxide is obtained.

3. The method for preparing a halogen-free high-gloss black pigment according to claim 2, characterized in that: In the first step, during the surface activation treatment, the mass fraction of sodium hydroxide is 10%-20%, and the mass volume ratio of cobalt oxide particles to sodium hydroxide solution is 1g:(10-20)mL.

4. The method for preparing a halogen-free high-gloss black pigment according to claim 1, characterized in that: In the second step, the preparation process of mercaptolated cobalt oxide includes: The coupling agent KH-580 was dissolved in ethanol, and the activated cobalt oxide was added, and the mixture was ultrasonically homogenized, and then refluxed at 65-75°C for 6-12 hours. After the reflux, the precipitate was centrifuged, washed with water three times, and vacuum dried to obtain thiolated cobalt oxide.

5. The method for preparing a halogen-free high-gloss black pigment according to claim 4, characterized in that: In the second step, the mass volume ratio of the activated cobalt oxide, coupling agent KH-580 and ethanol is 1 g: (0.1-0.5) g: (10-20) mL.

6. The method for preparing a halogen-free high-gloss black pigment according to claim 1, characterized in that: In the third step, the preparation process of the surface-modified cobalt oxide includes: The thiolated cobalt oxide and N-methylpyrrolidone are mixed, ultrasonically dispersed evenly at room temperature, 4-vinylaniline is added, and a photoinitiator is added at the same time. The mixture is stirred under ultraviolet light for 0.8-1.6 hours. After the reaction is completed, the precipitate is collected by centrifugation, washed three times with alcohol, and then dried to obtain surface-modified cobalt oxide.

7. The method for preparing a halogen-free high-gloss black pigment according to claim 6, characterized in that: In the third step, the mass volume ratio of mercaptolated cobalt oxide, 4-vinylaniline and N-methylpyrrolidone is 1 g: (0.23-0.46) g: (15-25) mL.

8. The method for preparing a halogen-free high-gloss black pigment according to claim 1, characterized in that: In the fourth step, the process of temperature-raising reaction treatment includes: The surface modified cobalt oxide and anhydrous ethanol are mixed, ultrasonically dispersed evenly, heated to 70-80°C under the condition of a reflux condenser, bisphenol A diglycidyl ether is added dropwise, and after the addition is completed, the mixture is kept warm and stirred for 2-3 hours, and the precipitate is collected by centrifugation, vacuum dried, and ground through a 200-mesh sieve to obtain a halogen-free high-gloss black pigment.

9. The method for preparing a halogen-free high-gloss black pigment according to claim 8, characterized in that: In the fourth step, the mass volume ratio of the surface-modified cobalt oxide, bisphenol A diglycidyl ether and anhydrous ethanol is 1 g: (0.57-1.14) g: (15-25) mL.

10. A halogen-free high-gloss black pigment, characterized in that: The preparation method according to claim 1 is used for preparation.

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