A bio-based disazo lake pigment and preparation method thereof

Abstract

The invention discloses a method for preparing a bio-based disazo lake pigment, comprising the following steps: S1, aniline compound is diazotized with sodium nitrite under the action of acid solution, and then coupled with 2,5-hydroxyterephthalic acid to prepare disazo-2,5-hydroxyterephthalic acid dye; S2, the disazo-2,5-hydroxyterephthalic acid dye prepared in step S1 is reacted with a metal salt in an aqueous solution to prepare a bio-based disazo lake pigment. In the present invention, the main raw material of the bio-based disazo lake pigment comes from biological fermentation, the preparation method is simple, and the structure has two pairs of adjacent hydroxyl groups and carboxyl groups, which can have a good complexing effect on metal ions, and is easy to form an intermolecular association to stabilize the metal ions. The organic lake pigment prepared by the present invention can tolerate a wide pH range without the freeing of metal ions when used to prepare an aqueous color paste, and does not affect the viscosity and tinting power of the color paste.

Description

Technical Field

[0001] The invention belongs to the technical field of organic pigments, colorants and water-based color pastes, and specifically relates to a bio-based disazo lake pigment and a preparation method thereof. Background Art

[0002] Color lake refers to the non-water-soluble colored substance precipitated by water-soluble dyes under the action of different types of precipitants in the presence of fillers, such as aluminum hydroxide, aluminum barium white, etc. The precipitants are mainly certain metal salts, such as CaCl2, BaCl2, Mn +2 , Fe +2 , Pb +2 Sn +2 , Sr +2 And trivalent metal salts such as Al +3 ,Cr +3 Etc., or organic bases (guanidines, diphenylguanidine), organic acids (tannic acid), inorganic heteroacids (phosphotungstic acid, phosphotungstomolybdic acid), etc.

[0003] Fillers in lake pigments not only act as diluents to reduce color strength, but also make the precipitated dyes dispersed evenly on the filler surface, preventing the aggregation of dye precipitates, thereby obtaining satisfactory application performance. According to the different adsorption activities of fillers, they can be divided into inert fillers or carriers, such as barite (barium sulfate), talc, etc.; active fillers, such as newly precipitated aluminum hydroxide, aluminum barium white (co-precipitation of aluminum hydroxide and barium sulfate), etc.

[0004] The production method of insoluble dye lakes is generally to completely dissolve the prepared dye first, then add a precipitant solution to precipitate the lake, and then filter, wash, dry, crush, and blend to obtain the finished product. Soluble dye lakes need to be made into an inorganic base powder (also called "carrier") in advance, and then the dissolved dye and base powder are mixed into a suspension, and finally a precipitant is added to make the dye an insoluble colored substance, which is precipitated on the base powder to form a lake.

[0005] Azo lakes are a large category of lake pigments. Soluble azo dyes with sulfonic acid or carboxyl groups are added to barium chloride or calcium chloride solutions to generate insoluble barium salt or calcium salt precipitates, called azo lakes. The development of azo lakes began with the synthesis of Lithol Red by Julius of BASF in 1899. The preparation method of Lithol Red is to diazotize 2-naphthylamine-1-sulfonic acid, couple it with 2-naphthol, and then rosinize and precipitate barium salts to obtain the product. Lithol Red pigment is one of the earliest colorants. As shown in the following formula:

[0006]

[0007] When making lakes from insoluble monoazo dyes with a sulfonic acid group or a carboxyl group, it is generally not necessary to add inorganic primer. In particular, when the sulfonic acid group or the carboxyl group is located at the ortho position of the azo group, the lake has better performance. For example, acid scarlet lake (Lisol Scarlet) is obtained by diazotizing Tobias acid and coupling it with 2-naphthol to obtain an insoluble monoazo dye, and then adding barium chloride solution to generate a lake. If calcium chloride is used as a precipitant, Lisol Scarlet is obtained.

[0008] When making lakes from easily soluble monoazo dyes, inorganic base powder is generally required. For example, the acid dye obtained from m-chloroaniline and 2',4'-dichlorobenzoyl-K acid is precipitated on the inorganic base powder of aluminum barium white using barium chloride as a precipitant to make a light-fast red. Common azo lake organic pigments include Pigment Red 63:1, Pigment Red 48:2, Pigment Red 57:1, Pigment Red 53:1, etc., and their structural formulas are as follows:

[0009]

[0010] In the existing organic lake pigments, the coupling component is usually 2-hydroxy-3-naphthoic acid-derived chromophore AS as a coupling component, or 2-naphthol as a coupling component, which mainly occurs at the 1st position of naphthol or chromophore AS for coupling. Such lake pigments can usually only be monoazo pigments; in view of the above shortcomings, CN103160135B proposes a method for preparing a strong green light yellow disazo organic pigment; Zhang Zhiqun studied a method for preparing a class of yellow disazo lake pigments (Synthesis of Yellow Disazo Lake Pigments, Master's Thesis of Dalian University of Technology, 2008). The preparation of the above disazo lake pigments often requires a diazonium salt component to provide a sulfonic acid group. Summary of the invention

[0011] The technical problem to be solved by the present invention is to provide a bio-based disazo lake pigment and a preparation method thereof. The raw materials for preparation are derived from biological fermentation, the preparation method is simple, and the structure has two pairs of adjacent hydroxyl groups and carboxyl groups, which can have a good complexing effect on metal ions and easily form an intermolecular association to stabilize the metal ions. When the prepared organic lake pigment is used to prepare water-based color paste, it can tolerate a wide pH range without the freeing of metal ions, and does not affect the viscosity and tinting strength of the color paste.

[0012] In order to solve the above technical problems, an embodiment of the present invention provides a bio-based disazo lake pigment, the structure of which is shown in Formula I:

[0013]

[0014] Among them, M 2+ Ca 2+ , Ba 2+ , Sr. 2+; R is one of H, Cl, Br, -NO2, -CH3, -CN, etc.; R1 is one of H, Cl, Br, -NO2, -CH3, -CN, etc.

[0015] The raw materials for preparing the bio-based disazo lake pigment include: aniline derivatives, 2,5-hydroxyterephthalic acid, and metal salts.

[0016] Preferably, the aniline derivatives include but are not limited to: p-chloroaniline, p-nitroaniline, m-nitroaniline, p-methylm-nitroaniline, p-cyanoaniline, o-chloro-p-nitroaniline, o-bromo-p-nitroaniline, o-chloro-p-cyanoaniline, and o-bromo-p-cyanoaniline.

[0017] Preferably, the metal salt includes but is not limited to one of CaCl2, BaCl2 and SrCl2.

[0018] The present invention also provides a method for preparing a bio-based disazo lake pigment, comprising the following steps:

[0019] S1. The aniline compound is diazotized with sodium nitrite under the action of an acid solution (hydrochloric acid or sulfuric acid), and then coupled with 2,5-hydroxyterephthalic acid to prepare a disazo-2,5-hydroxyterephthalic acid dye;

[0020] S2. Reacting the disazo-2,5-hydroxyterephthalic acid dye prepared in step S1 with a metal salt in an aqueous solution to obtain a bio-based disazo lake pigment.

[0021] Wherein, in step S1, the temperature for preparing the diazonium salt is 0-5°C, and the molar ratio of the diazonium salt to 2,5-hydroxyterephthalic acid is 2:0.9 to 2:1.1.

[0022] Wherein, in step S2, the metal salt is one of CaCl2, BaCl2 and SrCl2; and the molar ratio of the metal salt to the disazo-2,5-hydroxyterephthalic acid dye is 1:0.9 to 1:1.05.

[0023] The beneficial effects of the above technical solution of the present invention are as follows:

[0024] In the present invention, the main raw material of the bio-based disazo lake pigment comes from biological fermentation, the preparation method is simple, and the structure has two pairs of adjacent hydroxyl groups and carboxyl groups, which can have a good complexing effect on metal ions and easily form an intermolecular association to stabilize the metal ions. When the organic lake pigment prepared by the present invention is used to prepare water-based color paste, it can tolerate a wide pH range without the freeing of metal ions, and does not affect the viscosity and tinting strength of the color paste. DETAILED DESCRIPTION

[0025] In order to make the technical problems to be solved, technical solutions and advantages of the present invention more clear, they are described in detail below in conjunction with specific embodiments.

[0026] The present invention provides a bio-based disazo lake pigment, the structure of which is shown in Formula I:

[0027]

[0028] Among them, M 2+ Ca 2+ , Ba 2+ , Sr. 2+ ; R is one of H, Cl, Br, -NO2, -CH3, -CN, etc.; R1 is one of H, Cl, Br, -NO2, -CH3, -CN, etc.

[0029] The raw materials for preparing the bio-based disazo lake pigment include: aniline derivatives, 2,5-hydroxyterephthalic acid, and metal salts.

[0030] Preferably, the aniline derivatives include but are not limited to: p-chloroaniline, p-nitroaniline, m-nitroaniline, p-methylm-nitroaniline, p-cyanoaniline, o-chloro-p-nitroaniline, o-bromo-p-nitroaniline, o-chloro-p-cyanoaniline, and o-bromo-p-cyanoaniline.

[0031] The metal salt includes but is not limited to one of CaCl2, BaCl2 and SrCl2.

[0032] The present invention also provides a method for preparing a bio-based disazo lake pigment, comprising the following steps:

[0033] S1. The aniline compound is diazotized with sodium nitrite under the action of an acid solution (hydrochloric acid or sulfuric acid), and then coupled with 2,5-hydroxyterephthalic acid to prepare a disazo-2,5-hydroxyterephthalic acid dye; in this step, the temperature for preparing the diazonium salt is 0-5°C, and the molar ratio of the diazonium salt to the 2,5-hydroxyterephthalic acid is 2:0.9 to 2:1.1.

[0034] S2. Reacting the disazo-2,5-hydroxyterephthalic acid dye prepared in step S1 with a metal salt in an aqueous solution to obtain a bio-based disazo lake pigment; in this step, the metal salt is one of CaCl2, BaCl2 and SrCl2; and the molar ratio of the metal salt to the disazo-2,5-hydroxyterephthalic acid dye is 1:0.9 to 1:1.05.

[0035] The technical solution of the present invention is further described below in conjunction with specific embodiments.

[0036] Example 1

[0037] Add 13.8 g of nitroaniline, 10 mL of deionized water, and 20 mL of 30% hydrochloric acid into a beaker, cool to 0°C while stirring (use an ice water bath to cool the beaker), quickly add 7 g of sodium nitrite, and continue stirring for 0.5 hour to obtain a diazonium salt solution component.

[0038] Prepare 100 ml of 10% sodium carbonate solution and set aside.

[0039] In another 1000ml beaker, add 10.1g of 2,5-hydroxyterephthalic acid (produced by Sinopharm Group) and 100mL of deionized water, and cool to 0℃ in an ice-salt bath. Under ice-salt bath conditions, slowly add diazonium salt solution and 10% sodium carbonate solution to the 2,5-hydroxyterephthalic acid solution while stirring, keeping the reaction temperature in the range of 0-5℃ and the pH value at 5-6. With the addition of the diazo component, the color of the reaction solution gradually changes to brown. After the addition is complete, adjust the pH value of the reaction system to pH = 7.0-7.8 with 10% sodium hydroxide solution. Continue to add 11.5g of BaCl2 to the reaction system, heat to 80℃, stir and react for 50min, and obtain a dark red precipitate, which is a bio-based disazo lake pigment, numbered 1#.

[0040] Example 2

[0041] Add 15.2 g of 4-methyl-3-nitroaniline, 15 mL of deionized water, and 25 mL of 30% hydrochloric acid into a beaker, cool to 0°C while stirring (use an ice water bath to cool the beaker), quickly add 7 g of sodium nitrite, and continue stirring for 0.5 hour to obtain a diazonium salt solution component.

[0042] Prepare 100 ml of 15% sodium carbonate solution and set aside.

[0043] Add 10.1g of 2,5-hydroxyterephthalic acid (produced by Sinopharm Group) and 100mL of deionized water to a 1L beaker, and cool to 0°C in an ice-salt bath. Under ice-salt bath conditions, slowly add the diazonium salt solution and 15% sodium carbonate solution to the 2,5-hydroxyterephthalic acid solution while stirring, keeping the reaction temperature in the range of 0-5°C and the pH value at 5-6. With the addition of the diazo component, the color of the reaction solution gradually changes to brown. After the addition is complete, adjust the pH value of the reaction system to pH = 7.0-7.8 with 10% sodium hydroxide solution. Continue to add 9.36g of BaCl2 to the reaction system, heat to 80°C, stir and react for 50 minutes, and obtain a dark red precipitate, which is the bio-based disazo lake pigment, numbered 2#.

[0044] Example 3

[0045] Add 11.8 g of 4-cyanoaniline, 30 mL of deionized water, and 15 mL of 30% hydrochloric acid into a beaker, cool to 0°C while stirring (use an ice water bath to cool the beaker), quickly add 7.1 g of sodium nitrite, and continue stirring for 0.5 hour to obtain a diazonium salt solution component.

[0046] Prepare 100 ml of 15% sodium carbonate solution and set aside.

[0047] Add 9.1g of 2,5-hydroxyterephthalic acid (produced by Sinopharm Group) and 100mL of deionized water to a 1L beaker and cool to 0°C in an ice-salt bath. Under ice-salt bath conditions, slowly add the diazonium salt solution and 15% sodium carbonate solution to the 2,5-hydroxyterephthalic acid solution while stirring, keeping the reaction temperature in the range of 0-5°C and the pH value at 5-6. With the addition of the diazo component, the color of the reaction solution gradually changes to brown. After the addition is complete, adjust the pH value of the reaction system to pH = 7.0-7.8 with 10% sodium hydroxide solution. Continue to add 7.9g of SrCl2 to the reaction system, heat to 80°C, stir and react for 50 minutes, and obtain a red precipitate, which is a bio-based disazo lake pigment, numbered 3#.

[0048] Example 4

[0049] Add 16.3 g of 4-cyano-2-nitroaniline and 10 mL of 98% sulfuric acid into a beaker, cool to 0°C (use an ice water bath to cool the beaker) while stirring and beating, quickly add 7.1 g of sodium nitrite, and continue stirring for 0.5 hour to obtain a diazonium salt solution component.

[0050] Prepare 100 ml of 20% sodium carbonate solution and set aside.

[0051] Add 11.1g of 2,5-hydroxyterephthalic acid and 100mL of deionized water to a 1L beaker and cool to 0°C in an ice-salt bath. In an ice-salt bath, slowly add the diazonium salt solution and 20% sodium carbonate solution to the 2,5-hydroxyterephthalic acid solution while stirring, keeping the reaction temperature in the range of 0-5°C and the pH value at 5-6. With the addition of the diazo component, the color of the reaction solution gradually changes to reddish brown. After the addition is complete, adjust the pH value of the reaction system to pH = 7.0-7.8 with 10% sodium hydroxide solution. Continue to add 5.4g of CaCl2 to the reaction system, heat to 80°C, stir and react for 60 minutes, and obtain a reddish-brown precipitate, which is the bio-based disazo lake pigment, numbered 4#.

[0052] Example 5

[0053] Add 17.2 g of 4-chloro-2-nitroaniline and 9 mL of 98% sulfuric acid into a beaker, cool to 0°C (use an ice water bath to cool the beaker) while stirring and beating, quickly add 6.9 g of sodium nitrite, and continue stirring for 0.5 hours to obtain a diazonium salt solution component.

[0054] Prepare 100 ml of 20% sodium carbonate solution and set aside.

[0055] Add 9.08g of 2,5-hydroxyterephthalic acid and 100mL of deionized water to a 1L beaker and cool to 0°C in an ice-salt bath. Under ice-salt bath conditions, slowly add the diazonium salt solution and 20% sodium carbonate solution to the 2,5-hydroxyterephthalic acid solution while stirring, keeping the reaction temperature in the range of 0-5°C and the pH value at 5-6. With the addition of the diazo component, the color of the reaction solution gradually turns dark red. After the addition is complete, adjust the pH value of the reaction system to pH = 7.0-7.8 with 10% sodium hydroxide solution. Continue to add 9.36g of BaCl2 to the reaction system, heat to 80°C, stir and react for 60 minutes, and the red precipitate is the bio-based disazo lake pigment, number 5#.

[0056] Example 6

[0057] Add 16.3 g of 4-cyano-2-nitroaniline and 10 mL of 98% sulfuric acid into a beaker, cool to 0°C (use an ice water bath to cool the beaker) while stirring and beating, quickly add 7.1 g of sodium nitrite, and continue stirring for 0.5 hour to obtain a diazonium salt solution component.

[0058] Prepare 100 ml of 20% sodium carbonate solution and set aside.

[0059] Add 11.1g of 2,5-hydroxyterephthalic acid and 100mL of deionized water to a 1L beaker and cool to 0°C in an ice-salt bath. Under ice-salt bath conditions, slowly add the diazonium salt solution and 20% sodium carbonate solution to the 2,5-hydroxyterephthalic acid solution while stirring, keeping the reaction temperature in the range of 0-5°C and the pH value at 5-6. With the addition of the diazo component, the color of the reaction solution gradually changes to reddish brown. After the addition is complete, adjust the pH value of the reaction system to pH = 7.0-7.8 with 10% sodium hydroxide solution. Continue to add 8.1g of SrCl2 to the reaction system, heat to 80°C, stir and react for 60 minutes, and the brown precipitate is the bio-based disazo lake pigment, number 6#.

[0060] The diazo components and metal salts used in Examples 7 to 9 are shown in Table 1.

[0061] Table 1. Diazo components, metal salts and color of prepared lake pigments used in various examples

[0062]

[0063]

[0064] Performance Testing

[0065] (1) Testing of the performance of bio-based disazo lake pigments

[0066] Take the lake pigment in the example and prepare the pigment paste sanding liquid according to Table 2, then add 100g of glass beads (particle size 2-3mm), tighten the glass bottle, put the glass bottle into a SK450 vibration mixer (Shanghai Jingxin Industrial) and shake for 3 hours, then take out the glass bottle and let it stand for 48 hours.

[0067] Table 2. Pigment paste sanding formula

[0068]

[0069]

[0070] Particle size analysis of color paste

[0071] Take the upper layer of pigment emulsion from the glass bottle after it has settled, and measure the particle size of the pigment emulsion using a Mastersizer 3000 laser particle size analyzer. The sand-grinding formula of the pigment paste is shown in Table 2.

[0072] Freeze-thaw cycle testing of color paste

[0073] The pH values ​​of the pigment paste were adjusted to 5, 6, 7, 8, and 9 with 1% sodium hydrogen phosphate solution and 5% sodium carbonate solution, respectively. After shaking for 2 hours, the pigment paste was allowed to stand for 96 hours. Then, 20 ml of the pigment emulsion was taken from the upper layer of the emulsion in the glass bottle after standing and placed in a test tube to test the particle size of the emulsion. The test results are shown in Table 3. The upper emulsion was smeared on the color card and compared with the color card of the color paste at pH = 7 to determine the change in K / S value (△E) and viscosity (△η, viscosity increase △η is positive, viscosity increase △η is negative). The test results are shown in Table 4.

[0074] Table 3. Average particle size of color in color paste under different pH conditions (D50, nm)

[0075]

[0076]

[0077] Table 4. Changes in color and viscosity of color paste at different pH values ​​(compared with pH = 7)

[0078]

[0079] It can be seen from Tables 3 and 4 that within the pH range of 5-9, the particle size and viscosity of the aqueous color paste prepared by the disazo lake pigment of the present invention all show good emulsion stability.

[0080] In the present invention, the main raw material of the bio-based disazo lake pigment comes from biological fermentation, the preparation method is simple, and the structure has two pairs of adjacent hydroxyl groups and carboxyl groups, which can have a good complexing effect on metal ions and easily form an intermolecular association to stabilize the metal ions. When the organic lake pigment prepared by the present invention is used to prepare water-based color paste, it can tolerate a wide pH range without the freeing of metal ions, and does not affect the viscosity and tinting strength of the color paste.

[0081] The above is a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principles of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A bio-based disazo lake pigment, characterized in that: The structure is shown in Formula I: Among them, M 2+ Ca 2+ , Ba 2+ , Sr. 2+ ; R is one of H, Cl, Br, -NO2, -CH3, -CN, etc.; R1 is one of H, Cl, Br, -NO2, -CH3, -CN, etc.

2. The bio-based disazo lake pigment according to claim 1, characterized in that The raw materials for preparing the bio-based disazo lake pigment include: aniline derivatives, 2,5-hydroxyterephthalic acid, and metal salts.

3. The bio-based disazo lake pigment according to claim 2, characterized in that The aniline derivatives include: p-chloroaniline, p-nitroaniline, m-nitroaniline, p-methylm-nitroaniline, p-cyanoaniline, o-chloro-p-nitroaniline, o-bromo-p-nitroaniline, o-chloro-p-cyanoaniline and o-bromo-p-cyanoaniline.

4. The bio-based disazo lake pigment according to claim 2, characterized in that The metal salt is one of CaCl2, BaCl2 and SrCl2.

5. A method for preparing a bio-based disazo lake pigment as claimed in any one of claims 1 to 4, characterized in that: The steps include: S1, diazotizing the aniline compound with sodium nitrite under the action of an acid solution, and then coupling with 2,5-hydroxyterephthalic acid to prepare a disazo-2,5-hydroxyterephthalic acid dye; S2. Reacting the disazo-2,5-hydroxyterephthalic acid dye prepared in step S1 with a metal salt in an aqueous solution to obtain a bio-based disazo lake pigment.

6. The method for preparing the bio-based disazo lake pigment according to claim 5, characterized in that: In step S1, the temperature for preparing the diazonium salt is 0-5°C, and the molar ratio of the diazonium salt to 2,5-hydroxyterephthalic acid is 2:0.9 to 2:1.

1.

7. The method for preparing the bio-based disazo lake pigment according to claim 5, characterized in that: In step S2, the metal salt is one of CaCl2, BaCl2 and SrCl2; and the molar ratio of the metal salt to the disazo-2,5-hydroxyterephthalic acid dye is 1:0.9 to 1:1.05.

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