Aluminum-free, acid-resistant, alkali-resistant and antioxidant lake and preparation method thereof

Abstract

The invention discloses an aluminum-free, acid-resistant, alkali-resistant and antioxidant lake and a preparation method of the aluminum-free, acid-resistant, alkali-resistant and antioxidant lake. The preparation method of the lake comprises the following steps: uniformly mixing a silicon source, an organic solvent and deionized water, adjusting the solution to be acidic, and stirring for 2-8 hours to obtain a solution A; adjusting the pH value of the solution A to 7-8 by using an alkaline regulator, and continuously stirring to obtain a silicon dioxide colloidal particle solution B; dispersing the plant extract in a solvent, adding a pigment raw material, stirring and dispersing, adding an emulsifier, and stirring to obtain a pigment solution C; adding an amino coupling agent into the pigment solution C, heating and stirring to obtain a solution D; and adding the solution D into the silicon dioxide colloidal particle solution B, uniformly stirring, and carrying out spray drying under the protection of inert gas to obtain the aluminum-free acid-resistant alkali-resistant antioxidant lake. The obtained color lake not only has acid and alkali resistance, but also has oxidation resistance, and the used raw materials do not contain metals such as aluminum, barium, zirconium, calcium and strontium, so that the color lake is environment-friendly and pollution-free.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of material preparation, in particular to an acid and alkali resistant and oxidation resistant lake pigment and a preparation method thereof. BACKGROUND

[0002] Pigments can be divided into organic pigments and inorganic pigments, wherein the organic pigments include azo pigments, phthalocyanine pigments, acid-base dye lake pigments, condensed ring ketone pigments, nitroso pigments, alizarin lake pigments and the like. The organic pigments are good in coloring power, bright in color, and rich in color, and thus are applied in various industries. However, the organic pigments are poor in light resistance, heat resistance, acid and alkali resistance.

[0003] The lake pigment is one of the organic pigments. At present, the most common preparation method of the lake pigment is a metal salt precipitation method, that is, a water-soluble pigment is reacted with metal ions to generate an insoluble lake pigment. The metal salt precipitation method mainly relies on the adsorption of metal salts such as aluminum salt, calcium salt, barium salt, strontium salt and zirconium salt. After the adsorption is completed, the lake pigment is prepared by dehydration and drying. The lake pigment prepared by the method is poor in light resistance, heat resistance and acid and alkali resistance, and the adsorbed pigment molecules are easy to fall off, thereby causing discoloration. Moreover, the use of aluminum salt, calcium salt, barium salt, strontium salt and zirconium salt as a filler to prepare the lake pigment generates a large amount of wastewater containing metal ions, which is difficult to treat and is not friendly to the environment. SUMMARY

[0004] To solve the above technical problems, the present application provides an acid and alkali resistant and oxidation resistant lake pigment and a preparation method thereof. The present application uses plant extracts (such as tea polyphenols and aloe polysaccharides) to enhance the solubility of pigments, provide antioxidant groups, and protect pigments to make them stable. The polyphenols and organic acids (such as tannic acid and citric acid) in the plant extracts act as natural catalysts to complex with metal ions in the pigment molecules to form metal-pigment complexes. The complexes are connected with -NH2 at one end of the amino coupling agent, and the other end of the amino coupling agent is bonded with the hydrolyzed silica gel particles to form a bridge structure of "pigment-coupling agent-SiO2", which further enhances the acid and alkali resistance.

[0005] The first object of the present application is to provide a preparation method of an acid and alkali resistant and oxidation resistant lake pigment, which comprises the following steps:

[0006] Mixing a silicon source, an organic solvent and deionized water uniformly, and adjusting the solution to be acidic, and stirring for 2-8 hours to obtain a solution A; adjusting the pH value of the solution A to 7-8 by using an alkaline adjusting agent, and continuing to stir to obtain a silica gel particle solution B;

[0007] After the plant extract is dispersed in the solvent, the pigment raw material is added, stirred and dispersed, and then the emulsifier is added, stirred to obtain a pigment solution C; the amino coupling agent is added to the pigment solution C, heated and stirred to obtain a solution D;

[0008] The solution D is added to the silica colloidal particle solution B, stirred uniformly, and then atomized and dried under inert gas protection to obtain the acid and alkali resistant and oxidation resistant lake.

[0009] In some embodiments of the present application, the silicon source comprises one or more of tetraethyl orthosilicate, tetramethyl orthosilicate, methyltrimethoxysilane, methyltriethoxysilane, propyltrimethoxysilane, propyltriethoxysilane, acidic silica sol, neutral silica sol, and basic silica sol, preferably tetraethyl orthosilicate, tetramethyl orthosilicate, acidic silica sol, neutral silica sol, and more preferably tetraethyl orthosilicate;

[0010] The organic solvent comprises one or more of ethanol, methanol, butanol, benzyl alcohol, propylene glycol, and isopropyl alcohol, preferably ethanol;

[0011] The mass ratio of the silicon source, the organic solvent, and the deionized water is (2:5:1) to (2:20:1), preferably 2:8:1 to 2:15:1, and more preferably 2:10:1.

[0012] In some embodiments of the present application, the acidic pH value of the solution is adjusted to 3 to 5 by using an acidic adjusting agent; the acidic adjusting agent comprises one or more of hydrochloric acid, phosphoric acid, sulfuric acid, citric acid, oxalic acid, and benzoic acid, preferably hydrochloric acid, phosphoric acid, and citric acid, and more preferably hydrochloric acid.

[0013] In some embodiments of the present application, the particle size of the silica colloidal particles in the silica colloidal particle solution is 1 to 200 nm, preferably 10 to 150 nm, and more preferably 30 to 100 nm; the basic adjusting agent comprises one or more of sodium carbonate solution, sodium bicarbonate solution, potassium hydroxide solution, sodium hydroxide solution, calcium hydroxide solution, triethanolamine, ethylenediamine, and ammonia, preferably sodium carbonate solution, sodium bicarbonate solution, sodium hydroxide solution, and triethanolamine, and more preferably sodium hydroxide solution.

[0014] In some embodiments of the present application, the plant extract comprises one or more of anthocyanidin, crocin, carotene, lycopene, ellagic acid, tea polyphenol, rutin, phycocyanobilin, anthocyanin-protein complex, and aloe polysaccharide, preferably tea polyphenol and aloe polysaccharide; the solvent comprises one or more of water, ethanol, isopropyl alcohol, propylene glycol, acetone, diethyl ether, dichloromethane, n-hexane, and toluene, preferably water, ethanol, and isopropyl alcohol, and more preferably water.

[0015] In some embodiments of the present application, the emulsifier comprises one or more of soy lecithin, egg yolk lecithin, gum arabic, xanthan gum, Tween 80, Tween 60, Span 80, sucrose fatty acid ester, and sodium stearoyl lactylate, preferably Tween 80, Span 80, and more preferably Tween 80; and the pigment raw material comprises one or more of Red 40 (Allura Red), Red 30 (Erythrosine), Red 6, Red 7 (Carmine), Red 27 (Amaranth), Red 28 (Phloxine B), Red 33, Yellow 5 (Tartrazine), Yellow 6 (Sunset Yellow), Indigo, Blue 1 (Brilliant Blue), cochineal red, laccaic red, monascus red, and laccaic red, preferably Yellow 5 (Tartrazine) and Blue 1 (Brilliant Blue).

[0016] In some embodiments of the present application, the amino-based coupling agent comprises one or more of 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, N-(2-aminoethyl)-3-aminopropylmethyldimethoxysilane, 3-diethylenetriaminopropylmethyldimethylsilane, N,N-dimethylpropylenediaminopropylmethyldimethylsilane, 3-aminoethylaminopropyltrimethoxysilane, N-n-butyl-3-aminopropyltrimethoxysilane, anilino-propyltrimethoxysilane, and aminoalkyl-modified alkylsilane.

[0017] The temperature in the heating and stirring is 30-60°C, and the time is 1-5 hours.

[0018] In some embodiments of the present application, the mass ratio of the plant extract, solvent, pigment raw material, and emulsifier is (0.01:10:0.1:0.01) to (1:10:10:1); preferably 0.1:10:0.1:0.1 to 1:10:10:1, and more preferably 0.2:10:0.5:0.2 to 1:10:5:1.

[0019] The amount of the amino-based coupling agent is 0.1-20 Wt% of the pigment raw material, preferably 0.5-15 Wt%, and more preferably 1-10 Wt%.

[0020] In some embodiments of the present application, the inert gas is nitrogen and / or argon, preferably nitrogen.

[0021] The atomization drying is performed by ultrasonic atomization, the ultrasonic frequency is 1.0-2.5 MHz, preferably 1.7 MHz, and the drying temperature is 80-200°C, preferably 100°C.

[0022] A second object of the present application is to provide a lake free of aluminum and resistant to acid, alkali, and oxidation, prepared by the preparation method of any one of claims 1-9; the lake has a core-shell structure, with the pigment as the core and the silicon dioxide wrapped on the surface of the core as the shell, and the pigment and the silicon dioxide are connected by the coupling agent.

[0023] The above technical scheme of the present application has the following advantages compared with the prior art:

[0024] The plant extract (such as tea polyphenol, aloe polysaccharide, etc.) is used to enhance the solubility of the pigment, provide antioxidant groups, and protect the pigment to make it stable. The polyphenols and organic acids (such as tannic acid, citric acid, etc.) in the plant extract can complex with metal ions in the pigment molecules as a natural catalyst, forming a metal-pigment complex. The complex is connected to the -NH2 at one end of the amino coupling agent, and the other end of the amino coupling agent is bonded to the hydrolyzed silica gel particles, forming a "pigment-coupling agent-SiO2" bridge structure, which further enhances its acid and alkali resistance. Finally, the inert gas is used to protect the pigment from oxidative degradation, and the spray drying method is used to obtain the silica-coated lake particles. The obtained lake not only has acid and alkali resistance, but also has antioxidant capacity. Moreover, the raw materials used do not contain metals such as aluminum, barium, zirconium, calcium, and strontium, which are environmentally friendly and pollution-free. BRIEF DESCRIPTION OF DRAWINGS

[0025] In order to make the content of the present application more easily understood, the present application will be further described in detail below according to specific embodiments of the present application and in conjunction with the accompanying drawings, wherein,

[0026] Figure 1 is the experimental step schematic diagram of Example 8. DETAILED DESCRIPTION

[0027] The present application will be further described below in conjunction with the accompanying drawings and specific embodiments, so that those skilled in the art can better understand the present application and implement it. However, the embodiments are not limiting to the present application.

[0028] In the present application, except for the special description, the materials and equipment used in the embodiments can be purchased from the market.

[0029] Example 1

[0030] The present embodiment provides a preparation method of lake without aluminum and with acid and alkali resistance and antioxidant capacity, which is specifically as follows:

[0031] S1. 20g of tetraethyl orthosilicate, 100g of ethanol, and 10g of deionized water were mixed and stirred uniformly, then 0.5mol / L hydrochloric acid was used to adjust the pH to 4, and stirring was continued for 5 hours to obtain solution A;

[0032] S2. 0.5mol / L sodium hydroxide solution was added dropwise to solution A, the pH value was adjusted to 7.5, and stirring was continued. When the particle size of the silica gel particles reached 30nm, the stirring was stopped, and solution B was obtained;

[0033] S3. After 2g tea polyphenol is dispersed in 100g water by stirring, 5g yellow 5 (lemon yellow) pigment is added, and 2g Tween 80 is added after being dispersed by stirring to form a pigment solution C;

[0034] S4. 0.05g of 3-aminopropyltrimethoxysilane is added to solution C, heated to 50°C, and stirred for 3 hours to obtain solution D;

[0035] S5. Solution D is added to solution B, stirred for 30min, and then the mixture of solution D and solution B is atomized by an ultrasonic atomizer with a power of 100W and a frequency of 1.7MHz and then sent into a tubular furnace at 100°C for drying to obtain a color lake without aluminum and resistant to acid, alkali and oxidation.

[0036] Example 2

[0037] The present embodiment provides a preparation method of a color lake without aluminum and resistant to acid, alkali and oxidation, which is specifically as follows:

[0038] S1. 20g of tetraethyl orthosilicate, 100g of ethanol and 10g of deionized water are mixed and stirred uniformly, then the pH is adjusted to 4 with 0.5mol / L hydrochloric acid, and stirred for 5 hours to obtain solution A;

[0039] S2. 0.5mol / L sodium hydroxide solution is added dropwise to solution A to adjust the pH to 7.5, and stirring is continued. When the particle size of the silica gel particles reaches 30nm, stirring is stopped to obtain solution B;

[0040] S3. After 5g tea polyphenol is dispersed in 100g water by stirring, 5g yellow 5 (lemon yellow) pigment is added, and 2g Tween 80 is added after being dispersed by stirring to form a pigment solution C;

[0041] S4. 0.05g of 3-aminopropyltrimethoxysilane is added to solution C, heated to 50°C, and stirred for 3 hours to obtain solution D;

[0042] S5. Solution D is added to solution B, stirred for 30min, and then the mixture of solution D and solution B is atomized by an ultrasonic atomizer with a power of 100W and a frequency of 1.7MHz and then sent into a tubular furnace at 100°C for drying to obtain a color lake without aluminum and resistant to acid, alkali and oxidation.

[0043] Example 3

[0044] The present embodiment provides a preparation method of a color lake without aluminum and resistant to acid, alkali and oxidation, which is specifically as follows:

[0045] S1. 20 g of tetraethyl orthosilicate, 100 g of ethanol, 10 g of deionized water are mixed and stirred uniformly, then the pH is adjusted to 4 with 0.5 mol / L hydrochloric acid, and stirred for 5 hours to obtain solution A;

[0046] S2. A 0.5 mol / L sodium hydroxide solution is added dropwise to solution A, the pH value is adjusted to 7.5, and stirring is continued. When the silica colloid particle size reaches 30 nm, stirring is stopped, and solution B is obtained;

[0047] S3. 10 g of tea polyphenol is dispersed in 100 g of water, then 5 g of yellow 5 (lemon yellow) pigment is added, and after dispersion, 2 g of Tween 80 is added, and stirring is performed to form a pigment solution C;

[0048] S4. 0.05 g of 3-aminopropyltrimethoxysilane is added to solution C, heated to 50°C, and stirred for 3 hours to obtain solution D;

[0049] S5. Solution D is added to solution B, stirred for 30 min, and after nitrogen is introduced for 10 min, the mixture of solution D and solution B is atomized by an ultrasonic atomizer with a power of 100 W and a frequency of 1.7 MHz, and then sent into a tubular furnace at 100°C for drying, to obtain a color lake that is free of aluminum and resistant to acid, alkali and oxidation.

[0050] Example 4

[0051] The present embodiment provides a preparation method of a color lake that is free of aluminum and resistant to acid, alkali and oxidation, and is specifically as follows:

[0052] S1. 20 g of tetraethyl orthosilicate, 100 g of ethanol, 10 g of deionized water are mixed and stirred uniformly, then the pH is adjusted to 4 with 0.5 mol / L hydrochloric acid, and stirred for 5 hours to obtain solution A;

[0053] S2. A 0.5 mol / L sodium hydroxide solution is added dropwise to solution A, the pH value is adjusted to 7.5, and stirring is continued. When the silica colloid particle size reaches 30 nm, stirring is stopped, and solution B is obtained;

[0054] S3. 5 g of tea polyphenol is dispersed in 100 g of water, then 10 g of yellow 5 (lemon yellow) pigment is added, and after dispersion, 2 g of Tween 80 is added, and stirring is performed to form a pigment solution C;

[0055] S4. 0.1 g of 3-aminopropyltrimethoxysilane is added to solution C, heated to 50°C, and stirred for 3 hours to obtain solution D;

[0056] S5. Solution D is added to solution B, stirring for 30 min, after 10 min of nitrogen gas is introduced, the solution D and solution B mixture is atomized by ultrasonic atomizer with power 100 W, frequency 1.7 MHz, and then sent into a tube furnace at 100℃ for drying, to obtain a lake that is free of aluminum and resistant to acid, alkali and oxidation.

[0057] Example 5

[0058] The present embodiment provides a method for preparing a lake that is free of aluminum and resistant to acid, alkali and oxidation, which is specifically shown as follows:

[0059] S1. 20 g of tetraethyl orthosilicate, 100 g of ethanol, and 10 g of deionized water are mixed and stirred uniformly, then 0.5 mol / L hydrochloric acid is used to adjust the pH to 4, and stirring is continued for 5 hours to obtain solution A;

[0060] S2. 0.5 mol / L sodium hydroxide solution is added dropwise to solution A, the pH value is adjusted to 7.5, and stirring is continued. When the particle size of the silica gel particles reaches 30 nm, stirring is stopped to obtain solution B;

[0061] S3. 5 g of tea polyphenol is dispersed in 100 g of water, then 50 g of yellow 5 (lemon yellow) pigment is added, and after stirring and dispersing, 2 g of Tween 80 is added, and stirring is continued to uniformly form a pigment solution C;

[0062] S4. 0.5 g of 3-aminopropyltrimethoxysilane is added to solution C, heated to 50℃, and stirred for 3 hours to obtain solution D;

[0063] S5. Solution D is added to solution B, stirring for 30 min, after 10 min of nitrogen gas is introduced, the solution D and solution B mixture is atomized by ultrasonic atomizer with power 100 W, frequency 1.7 MHz, and then sent into a tube furnace at 100℃ for drying, to obtain a lake that is free of aluminum and resistant to acid, alkali and oxidation.

[0064] Example 6

[0065] The present embodiment provides a method for preparing a lake that is free of aluminum and resistant to acid, alkali and oxidation, which is specifically shown as follows:

[0066] S1. 20 g of tetraethyl orthosilicate, 100 g of ethanol, and 10 g of deionized water are mixed and stirred uniformly, then 0.5 mol / L hydrochloric acid is used to adjust the pH to 4, and stirring is continued for 5 hours to obtain solution A;

[0067] S2. 0.5 mol / L sodium hydroxide solution is added dropwise to solution A, the pH value is adjusted to 7.5, and stirring is continued. When the particle size of the silica gel particles reaches 30 nm, stirring is stopped to obtain solution B;

[0068] S3. After 5g tea polyphenol is dispersed in 100g water by stirring, 10g yellow 5 (lemon yellow) pigment is added, and after being dispersed by stirring, 5g Tween 80 is added, and the mixture is stirred to form a pigment solution C;

[0069] S4. 0.1g of 3-aminopropyltrimethoxysilane is added to solution C, heated to 50°C, and stirred for 3 hours to obtain solution D;

[0070] S5. Solution D is added to solution B, stirred for 30min, and after nitrogen is introduced for 10min, the mixture of solution D and solution B is atomized by an ultrasonic atomizer with a power of 100W and a frequency of 1.7MHz, and then sent into a tubular furnace at 100°C for drying, to obtain a lake that is free of aluminum and resistant to acid, alkali and oxidation.

[0071] Example 7

[0072] The present example provides a method for preparing a lake that is free of aluminum and resistant to acid, alkali and oxidation, which is specifically shown as follows:

[0073] S1. 20g of tetraethyl orthosilicate, 100g of ethanol and 10g of deionized water are mixed and stirred uniformly, then the pH is adjusted to 4 with 0.5mol / L hydrochloric acid, and stirred for 5 hours to obtain solution A;

[0074] S2. 0.5mol / L sodium hydroxide solution is added dropwise to solution A, the pH value is adjusted to 7.5, and stirring is continued. When the particle size of the silica gel particles reaches 30nm, stirring is stopped to obtain solution B;

[0075] S3. After 5g tea polyphenol is dispersed in 100g water by stirring, 10g yellow 5 (lemon yellow) pigment is added, and after being dispersed by stirring, 10g Tween 80 is added, and the mixture is stirred to form a pigment solution C;

[0076] S4. 0.1g of 3-aminopropyltrimethoxysilane is added to solution C, heated to 50°C, and stirred for 3 hours to obtain solution D;

[0077] S5. Solution D is added to solution B, stirred for 30min, and after nitrogen is introduced for 10min, the mixture of solution D and solution B is atomized by an ultrasonic atomizer with a power of 100W and a frequency of 1.7MHz, and then sent into a tubular furnace at 100°C for drying, to obtain a lake that is free of aluminum and resistant to acid, alkali and oxidation.

[0078] Example 8

[0079] The present example provides a method for preparing a lake that is free of aluminum and resistant to acid, alkali and oxidation, which is specifically shown as follows:

[0080] S1. 20 g of tetraethyl orthosilicate, 100 g of ethanol, 10 g of deionized water were mixed and stirred uniformly, then the pH was adjusted to 4 with 0.5 mol / L hydrochloric acid, and stirred for 5 hours to obtain solution A;

[0081] S2. A 0.5 mol / L sodium hydroxide solution was added dropwise to solution A, the pH value was adjusted to 7.5, and stirring was continued. When the silica colloid particle size reached 30 nm, stirring was stopped, and solution B was obtained.

[0082] S3. 5 g of tea polyphenol was dispersed in 100 g of water, then 10 g of yellow 5 (lemon yellow) pigment was added, and after stirring and dispersing, 5 g of Tween 80 was added. Stirring was performed to form a pigment solution C.

[0083] S4. 0.5 g of 3-aminopropyltrimethoxysilane was added to solution C, heated to 50°C, and stirred for 3 hours to obtain solution D.

[0084] S5. Solution D was added to solution B and stirred for 30 min. After 10 min of nitrogen gas was introduced, the mixture of solution D and solution B was atomized by an ultrasonic atomizer with a power of 100 W and a frequency of 1.7 MHz, and then sent into a tubular furnace at 100°C for drying to obtain a color lake without aluminum and resistant to acid, alkali and oxidation.

[0085] Example 9

[0086] The present embodiment provides a method for preparing a color lake without aluminum and resistant to acid, alkali and oxidation, which is specifically as follows:

[0087] S1. 20 g of tetraethyl orthosilicate, 100 g of ethanol, 10 g of deionized water were mixed and stirred uniformly, then the pH was adjusted to 4 with 0.5 mol / L hydrochloric acid, and stirred for 5 hours to obtain solution A;

[0088] S2. A 0.5 mol / L sodium hydroxide solution was added dropwise to solution A, the pH value was adjusted to 7.5, and stirring was continued. When the silica colloid particle size reached 30 nm, stirring was stopped, and solution B was obtained.

[0089] S3. 5 g of tea polyphenol was dispersed in 100 g of water, then 10 g of yellow 5 (lemon yellow) pigment was added, and after stirring and dispersing, 5 g of Tween 80 was added. Stirring was performed to form a pigment solution C.

[0090] S4. 1 g of 3-aminopropyltrimethoxysilane was added to solution C, heated to 50°C, and stirred for 3 hours to obtain solution D.

[0091] S5. Solution D is added to solution B, stirring for 30 min, after 10 min of nitrogen gas is introduced, the solution D and solution B mixture is atomized by ultrasonic atomizer with power 100 W, frequency 1.7 MHz, and then sent into a tube furnace at 100℃ for drying, to obtain a lake that is free of aluminum and resistant to acid, alkali and oxidation.

[0092] Example 10

[0093] The present embodiment provides a method for preparing a lake that is free of aluminum and resistant to acid, alkali and oxidation, which is specifically shown as follows:

[0094] S1. 20 g of tetraethyl orthosilicate, 100 g of ethanol, and 10 g of deionized water are mixed and stirred uniformly, then 0.5 mol / L hydrochloric acid is used to adjust the pH to 4, and stirring is continued for 5 hours to obtain solution A;

[0095] S2. 0.5 mol / L sodium hydroxide solution is added dropwise to solution A, the pH value is adjusted to 7.5, and stirring is continued. When the particle size of the silica gel particles reaches 60 nm, stirring is stopped, and solution B is obtained;

[0096] S3. 5 g of tea polyphenol is dispersed in 100 g of water, then 10 g of yellow 5 (lemon yellow) pigment is added, and after stirring and dispersing, 5 g of Tween 80 is added, and stirring is continued until the pigment solution C is uniformly formed;

[0097] S4. 0.5 g of 3-aminopropyltrimethoxysilane is added to solution C, heated to 50℃, and stirred for 3 hours to obtain solution D;

[0098] S5. Solution D is added to solution B, stirring for 30 min, after 10 min of nitrogen gas is introduced, the solution D and solution B mixture is atomized by ultrasonic atomizer with power 100 W, frequency 1.7 MHz, and then sent into a tube furnace at 100℃ for drying, to obtain a lake that is free of aluminum and resistant to acid, alkali and oxidation.

[0099] Example 11

[0100] The present embodiment provides a method for preparing a lake that is free of aluminum and resistant to acid, alkali and oxidation, which is specifically shown as follows:

[0101] S1. 20 g of tetraethyl orthosilicate, 100 g of ethanol, and 10 g of deionized water are mixed and stirred uniformly, then 0.5 mol / L hydrochloric acid is used to adjust the pH to 4, and stirring is continued for 5 hours to obtain solution A;

[0102] S2. 0.5 mol / L sodium hydroxide solution is added dropwise to solution A, the pH value is adjusted to 7.5, and stirring is continued. When the particle size of the silica gel particles reaches 100 nm, stirring is stopped, and solution B is obtained;

[0103] S3. After 5g tea polyphenols are dispersed in 100g water by stirring, 10g yellow 5 (lemon yellow) pigment is added, and after being dispersed by stirring, 5g Tween 80 is added, and the mixture is stirred to form a pigment solution C;

[0104] S4. 0.5g of 3-aminopropyltrimethoxysilane is added to solution C, heated to 50°C, and stirred for 3 hours to obtain solution D;

[0105] S5. Solution D is added to solution B, stirred for 30min, and after nitrogen is introduced for 10min, the mixture of solution D and solution B is atomized by an ultrasonic atomizer with a power of 100W and a frequency of 1.7MHz, and then sent into a tubular furnace at 100°C for drying, to obtain an aluminum-free, acid- and alkali-resistant, and oxidation-resistant lake.

[0106] Example 12

[0107] The present example provides a method for preparing an aluminum-free, acid- and alkali-resistant, and oxidation-resistant lake, which is specifically as follows:

[0108] S1. 20g of tetraethyl orthosilicate, 100g of ethanol, and 10g of deionized water are mixed and stirred uniformly, then the pH is adjusted to 4 with 0.5mol / L hydrochloric acid, and stirred for 5 hours to obtain solution A;

[0109] S2. 0.5mol / L sodium hydroxide solution is added dropwise to solution A to adjust the pH to 7.5, and stirring is continued. When the particle size of the silica gel particles reaches 30nm, stirring is stopped to obtain solution B;

[0110] S3. After 5g of aloe polysaccharide is dispersed in 100g of water by stirring, 10g of yellow 5 (lemon yellow) pigment is added, and after being dispersed by stirring, 5g of Tween 80 is added, and the mixture is stirred to form a pigment solution C;

[0111] S4. 0.5g of 3-aminopropyltrimethoxysilane is added to solution C, heated to 50°C, and stirred for 3 hours to obtain solution D;

[0112] S5. Solution D is added to solution B, stirred for 30min, and after nitrogen is introduced for 10min, the mixture of solution D and solution B is atomized by an ultrasonic atomizer with a power of 100W and a frequency of 1.7MHz, and then sent into a tubular furnace at 100°C for drying, to obtain an aluminum-free, acid- and alkali-resistant, and oxidation-resistant lake.

[0113] Example 13

[0114] The present example provides a method for preparing an aluminum-free, acid- and alkali-resistant, and oxidation-resistant lake, which is specifically as follows:

[0115] S1. 20 g of tetraethyl orthosilicate, 100 g of ethanol, 10 g of deionized water were mixed and stirred uniformly, then 0.5 mol / L hydrochloric acid was used to adjust the pH to 4, and stirred for 5 hours to obtain solution A;

[0116] S2. 0.5 mol / L sodium hydroxide solution was added to solution A, the pH value was adjusted to 7.5, and the stirring was continued. When the particle size of the silica gel particles reached 30 nm, the stirring was stopped, and solution B was obtained;

[0117] S3. 5 g of tea polyphenol was dispersed in 100 g of water, then 10 g of blue 1 (bright blue) pigment was added, and after stirring and dispersing, 5 g of Tween 80 was added, and the mixture was stirred to form a pigment solution C;

[0118] S4. 0.5 g of 3-aminopropyltrimethoxysilane was added to solution C, heated to 50°C, and stirred for 3 hours to obtain solution D;

[0119] S5. Solution D was added to solution B and stirred for 30 min. After 10 min of nitrogen gas was introduced, the mixture of solution D and solution B was atomized by an ultrasonic atomizer with a power of 100 W and a frequency of 1.7 MHz, and then sent into a tubular furnace at 100°C for drying to obtain a color lake that is free of aluminum and resistant to acid, alkali and oxidation.

[0120] Comparative Example 1

[0121] This comparative example provides a method for preparing a color lake that is free of aluminum and resistant to acid, alkali and oxidation. This comparative example is similar to Example 8, except that no plant extract tea polyphenol is added in step S3.

[0122] Comparative Example 2

[0123] This comparative example provides a method for preparing a color lake that is free of aluminum and resistant to acid, alkali and oxidation. This comparative example is similar to Example 8, except that no amino coupling agent is added in step S4.

[0124] Comparative Example 3

[0125] This comparative example provides a method for preparing a color lake that is free of aluminum and resistant to acid, alkali and oxidation. This comparative example is similar to Example 8, except that no emulsifier Tween 80 is added in step S3.

[0126] Comparative Example 4

[0127] This comparative example provides a method for preparing a color lake that is free of aluminum and resistant to acid, alkali and oxidation. This comparative example is similar to Example 8, except that no atomization drying is performed in step S5, but ordinary high-temperature drying is performed, specifically:

[0128] S5. Solution D was added to solution B, after stirring for 30 min, dehydration filtration, drying in oven at 100°C, to obtain a lake which was free of aluminum and resistant to acid and alkali and oxidation.

[0129] Performance test:

[0130] Acid and alkali resistance test, first the lake powder was dried at 105°C to constant weight to eliminate moisture interference. Acid resistance test: 2% sulfuric acid solution was used to adjust the pH of deionized water to 1, the dried lake powder was added and stirred, soaked for 24 hours, dehydrated and washed to neutral, after drying, compared with the lake which was not treated with acid, the color difference was tested by color difference meter to obtain ΔE value; alkali resistance test: 2% sodium hydroxide solution was used to adjust the pH of deionized water to 13, the dried lake powder was added and stirred, soaked for 24 hours, dehydrated and washed to neutral, after drying, compared with the lake which was not treated with acid, the color difference was tested by color difference meter to obtain ΔE value. The color difference meter used for testing color difference here was Color Spectrum DS-700D, according to the operation instruction, the lake which was not treated with acid and alkali was compared with the sample which was treated with acid and alkali, the larger the ΔE value, the greater the color difference, if the ΔE value was within 1, the color was stable, if the ΔE value was within 0.5, there was basically no color difference, if the ΔE value was more than 3, the change was obvious.

[0131] Antioxidant test: ORAC method (oxygen radical absorbance capacity method) was used, which is a method for evaluating the total antioxidant capacity of samples by fluorescence probe decay kinetics. The basic principle is that azo compound APPH (2, 2-azobis (2-amidinopropane) dihydrochloride) is thermally decomposed at 37°C to generate peroxy free radicals (ROO·). Free radicals attack sodium fluorescein and abstract the hydrogen atom of its phenolic hydroxyl group, triggering the oxidative degradation of sodium fluorescein, resulting in the gradual decay of fluorescein intensity (excitation wavelength 485 nm, emission wavelength 520-527 nm). Antioxidants in the sample preferentially react with free radicals through a hydrogen atom transfer mechanism, delaying the decay of fluorescein, and the degree of delay is positively correlated with antioxidant capacity. The antioxidant effect is characterized by the area under the fluorescence decay curve (AUC), and the greater the AUC, the stronger the antioxidant capacity. The specific operation steps are as follows: first, prepare the sodium fluorescein working solution. Take the sodium fluorescein stock solution (such as 40 mg / L) and dilute it with 75 mmol / L phosphate buffer (pH 7.4) to a final concentration of 61.2-63 nM. Then prepare the free radical initiator (APPH). Prepare 153 mM APPH solution (such as 207 mg APPH dissolved in 5 mL buffer) in an ice bath. Then draw the Trolox standard curve. Dilute the Trolox stock solution (1 mM) to a series of concentrations from 0 to 50 μm (such as 0, 2.5, 5, 10, 20, 40 μm), and prepare the color lake sample according to the above concentration gradient. Use the fluorescence enzyme label instrument to test according to the operation. Add 160 μL of sodium fluorescein working solution, 20 μL of sample / Trolox standard solution, and 20 μL of APPH solution. Set the excitation light to 485±20 nm and the emission light to 520-527 nm. Read the fluorescence value every 2 minutes for 60 minutes. According to the formula AUC = ∑ n-1 (F i +F i+1 ) / 2×Δt, where F i is the fluorescence value at the ith time point.

[0132] Table 1 is the test results of Examples 1 to 13 and Comparative Examples 1 to 4

[0133]

[0134]

[0135] From Table 1, it can be seen that, compared with Example 1, Example 2 and Example 3, the amount of plant extract tea polyphenol affects the color difference ΔE value and the antioxidant capacity AUC value in the acid and alkali resistance test, and with the increase of the amount of plant extract tea polyphenol, the color difference is smaller, and the antioxidant capacity AUC value is higher, but the plant extract tea polyphenol is not the more the better, and from the comparison of Example 2 and Example 3, it can be seen that after the amount of plant extract tea polyphenol is doubled, the color difference ΔE value and the antioxidant capacity AUC value are basically unchanged, because the metal ions in the pigment are certain, and after all the metal ions are complexed with the plant extract, there will be residual plant extract. In the examples of the present application, the mass ratio of the amount of plant extract to the amount of pigment is 1:2, which is the most suitable.

[0136] From the comparison of Example 2, Example 4 and Example 5, it can be seen that when the amount of pigment yellow 5 (lemon yellow) is increased, the color difference ΔE value is reduced, and the antioxidant capacity AUC value is increased, because the increase of the amount of pigment can increase the pigment content of the final lake, and the higher the pigment content, the stronger the hiding power, and when the acid and alkali and antioxidant tests are carried out, the discoloration rate is lower, and the color difference ΔE value is smaller, but the pigment content is not the higher the better, because the amount of silica gel particles in the system is certain, and the adsorbed pigment content is limited. In the examples of the present application, the mass ratio of the amount of pigment to the amount of silicon source is 1:2, which is the most suitable.

[0137] From the comparison of Example 4, Example 6 and Example 7, it can be seen that with the increase of the amount of emulsifier Tween 80, the color difference ΔE value is reduced, and the antioxidant capacity AUC value is increased, because the emulsifier can make the pigment more uniformly dispersed in the solvent, and after better dispersion, the efficiency of complexation reaction between the metal ions on the pigment and the plant extract is improved. However, the amount of emulsifier is not the more the better, and the amount of pigment in the system is certain, and the role of emulsifier is to disperse the pigment, and when the pigment is completely dispersed, the emulsifier has no effect. In the examples of the present application, the mass ratio of the amount of emulsifier to the amount of pigment is 1:2, which is the most suitable.

[0138] From the comparison of Example 6, Example 8 and Example 9, the amount of amino coupling agent 3-aminopropyltrimethoxysilane is increased, the color difference ΔE value is reduced, and the antioxidant capacity AUC value is increased, because the amino coupling agent can enhance the adsorption of metal-pigment complex on one hand, and enhance the bonding with silica colloidal particles on the other hand, so that the pigment is more firmly adsorbed in the silica colloidal particles, but the more amino coupling agent is not better, because the metal-pigment complex is limited, when the metal-pigment complex is fully combined with the -NH2 bond on the amino coupling agent, increasing the amount of amino coupling agent has no effect. In the examples of the present application, the amount of amino coupling agent is 5wt% of the amount of pigment, which is the best effect.

[0139] From the comparison of Example 8, Example 10 and Example 11, the particle size of silica colloidal particles will affect the color difference ΔE value and the antioxidant capacity AUC value to some extent, when the particle size of silica colloidal particles is larger, the color difference ΔE value is larger, and the antioxidant capacity AUC value is smaller, because the larger the particle size of silica colloidal particles, the larger the prepared color lake particles, and the weaker the color hiding power, after acid and alkali treatment, the discoloration will be faster and more obvious. In the examples of the present application, when the particle size of silica colloidal particles is 30nm, it is the most suitable.

[0140] From the comparison of Example 8 and Example 12, the use of tea polyphenol as a plant extract is better than the use of aloe polysaccharide, and the color difference ΔE value of tea polyphenol is smaller than that of aloe polysaccharide.

[0141] From the comparison of Example 8 and Example 13, the color difference ΔE value of lemon yellow and bright blue is basically the same, which shows that this method is suitable for different pigment raw materials.

[0142] From the comparison of Example 8 and Comparative Example 1, the color difference ΔE value of Comparative Example 1 without using plant extract is significantly higher than that of Example 8, which shows that plant extract plays a great role in the preparation of color lake, because plant extract can provide antioxidant groups on one hand, and can complex with metal ions on the pigment on the other hand, plant extract, complex reaction will be very slow or even disappear, the prepared color lake will not be firm, the pigment is easy to fall off, resulting in poor acid and alkali resistance.

[0143] From the comparison between Example 8 and Comparative Example 2, it can be seen that Comparative Example 2 does not use an amino coupling agent, and its color difference ΔE value is obviously higher than that of Example 8, which shows that the amino coupling agent plays a great role in the preparation of the lake, because the amino coupling agent here acts as a linker, one end of which provides -NH2 for connection with the pigment-metal complex, and the other end of which forms a stable Si-O-Si bond with the Si-OH bond on the silica colloidal particle, thus finally forming a stable bridge structure of "pigment-coupling agent-SiO2". In the absence of the amino coupling agent, the pigment cannot be firmly adsorbed on the silica colloidal particle, and is easily detached, resulting in poor acid and alkali resistance and poor oxidation resistance of the prepared lake.

[0144] From the comparison between Example 8 and Comparative Example 3, it can be seen that Comparative Example 3 does not use an emulsifier, and its color difference ΔE value is higher than that of Example 8, because the emulsifier here makes the pigment more completely dispersed in the solvent, improves the complexing rate of the metal ion with the plant extract, and thus improves the adsorption rate of the pigment. After the adsorption rate is improved, the acid and alkali resistance of the lake is better.

[0145] From the comparison between Example 8 and Comparative Example 4, it can be seen that Comparative Example 4 does not use the atomization drying method, but uses a simple high-temperature drying method, and its color difference ΔE value is higher than that of Example 8, because simple high-temperature drying is prone to cause agglomeration of the lake. The agglomerated lake has insufficient color development and hiding power, and simple high-temperature drying is not protected by inert gas, which is prone to cause oxidation and decomposition of the pigment molecules, and thus reduces the content of the pigment. Finally, when the acid and alkali resistance and oxidation resistance tests are performed, discoloration is prone to occur.

[0146] From the above test results (Table 1), it can be seen that the effect of Example 8 is the best, i.e., when the mass ratio of the silicon source, the organic solvent and the deionized water is 2:10:1, and the particle size of the silica colloidal particle is 30 nm, and the mass ratio of the plant extract, the solvent, the pigment and the emulsifier is 0.5:10:1:0.5, and the amount of the amino coupling agent is 5% of the amount of the pigment, the performance is the best.

[0147] Obviously, the above examples are merely examples for the purpose of clear illustration, and are not limiting of the embodiments. Based on the above description, other different forms of changes or variations can be made by those of ordinary skill in the art. Here, it is not necessary and impossible to exhaust all the embodiments. The obvious changes or variations derived therefrom are still within the protection scope of the present application.

Claims

1. A method for preparing an aluminum-free, acid- and alkali-resistant, oxidation-resistant lake, characterized by, The method comprises the following steps: Mixing the silicon source, organic solvent and deionized water uniformly, and adjusting the solution to be acidic, and stirring for 2-8 hours to obtain solution A; adjusting the pH value of solution A to 7-8 by using an alkaline adjusting agent, and continuing to stir to obtain silica colloidal particle solution B; After dispersing the plant extract in a solvent, adding a pigment raw material, stirring and dispersing, and then adding an emulsifier, and stirring to obtain pigment solution C; Adding an amino coupling agent to pigment solution C, and heating and stirring to obtain solution D; Adding solution D to silica colloidal particle solution B, stirring uniformly, and then atomizing and drying under the protection of inert gas to obtain the aluminum-free, acid- and alkali-resistant and oxidation-resistant lake.

2. The production method according to claim 1, characterized by, The silicon source comprises one or more of tetraethyl orthosilicate, tetramethyl orthosilicate, methyltrimethoxysilane, methyltriethoxysilane, propyltrimethoxysilane, propyltriethoxysilane, acidic silica sol, neutral silica sol and alkaline silica sol; The organic solvent comprises one or more of ethanol, methanol, butanol, benzyl alcohol, propylene glycol and isopropyl alcohol; The mass ratio of the silicon source, organic solvent and deionized water is (2:5:1)-(2:20:1).

3. The preparation method according to claim 1, characterized in that, The acidic pH value of the solution is adjusted to 3-5 by using an acidic adjusting agent; the acidic adjusting agent is one or more of hydrochloric acid, phosphoric acid, sulfuric acid, citric acid, oxalic acid and benzoic acid.

4. The method of claim 1, wherein, The particle size of the silica colloidal particles in the silica colloidal particle solution is 1-200 nm; the alkaline adjusting agent comprises one or more of sodium carbonate solution, sodium bicarbonate solution, potassium hydroxide solution, sodium hydroxide solution, calcium hydroxide solution, triethanolamine, ethylenediamine and ammonia water.

5. The preparation method according to claim 1, characterized in that, The plant extract is one or more of anthocyanin, crocin, carotene, lycopene, ellagic acid, tea polyphenol, rutin, phycocyanobilin, anthocyanin-protein complex and aloe polysaccharide; and the solvent is one or more of water, ethanol, isopropyl alcohol, propylene glycol, acetone, diethyl ether, dichloromethane, n-hexane and toluene.

6. The method of claim 1, wherein, The emulsifier comprises one or more of soybean lecithin, egg yolk lecithin, gum arabic, xanthan gum, Tween 80, Tween 60, Span 80, sucrose fatty acid ester and sodium stearoyl lactylate; and the pigment raw material is one or more of red 40, red 30, red 6, red 7, red 27, red 28, red 33, yellow 5, yellow 6, indigo, blue 1, cochineal red, laccaic acid, monascus red and shellac red.

7. The preparation method according to claim 1, characterized in that, The amino coupling agent is one or more of 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, N-(2-aminoethyl)-3-aminopropylmethyldimethoxysilane, 3-diethylenetriaminopropylmethyldimethylsilane, N,N-dimethylpropylenediaminepropylmethyldimethylsilane, 3-aminoethylaminopropyltrimethoxysilane, N-n-butyl-3-aminopropyltrimethoxysilane, anilinylpropyltrimethoxysilane and aminoalkyl-modified alkylsilane. The temperature in the heating and stirring is 30-60℃, and the time is 1-5 hours.

8. The method of claim 1, wherein, The mass ratio of the plant extract, solvent, pigment raw material and emulsifier is (0.01:10:0.1:0.01)-(1:10:10:1). The amount of the amino coupling agent is 0.1-20 wt% of the pigment raw material.

9. The method of claim 1, wherein, The inert gas is nitrogen and / or argon; The atomization drying adopts an ultrasonic atomization mode, the ultrasonic frequency is 1.0-2.5 MHz, and the drying temperature is 80-200 DEG C.

10. A lake which is free from aluminum and is resistant to acid, alkali and oxidation, characterized in that, The obtained pigment is prepared by the preparation method in any one of claims 1-9, has a core-shell structure, and is characterized in that the pigment is a core, and the silicon dioxide wrapped on the surface of the core is a shell, and the pigment and the silicon dioxide are connected by a coupling agent.

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