CN108752978B

CN108752978B - Green-phase golden pearlescent pigment based on synthetic mica and preparation method and application thereof

Info

Publication number: CN108752978B
Application number: CN201810751926.2A
Authority: CN
Inventors: 费明; 丁家国; 邱玉琴; 谢秉昆
Original assignee: Fujian Kuncai Material Technology Co ltd
Current assignee: Fujian Kuncai Material Technology Co ltd
Priority date: 2018-07-10
Filing date: 2018-07-10
Publication date: 2020-05-08
Anticipated expiration: 2038-07-10
Also published as: CN108752978A

Abstract

The invention provides a green-phase golden pearlescent pigment based on synthetic mica and a preparation method and application thereof. Synthetic mica is used as a base material, oxides with high and low refractive indexes are coated alternately to form a plurality of non-uniform interfaces, and the thickness of each coating layer of the bead is controlled to form the pearlescent pigment for enhancing chroma and brightness. In particular, the low-refraction coating layer is a composite oxide with colored low refractive index, and a cobalt oxide-doped titanium dioxide layer is adopted, so that the high-chroma green-phase gold pigment is obtained.

Description

Green-phase golden pearlescent pigment based on synthetic mica and preparation method and application thereof

Technical Field

The invention relates to the technical field of daily-use chemical industry, in particular to a green phase golden pearlescent pigment based on synthetic mica and a preparation method and application thereof.

Background

The golden color is associated with aesthetic feeling, quality and uniqueness, can always attract eyes and attract attention and desire. Products that claim unique and luxury are always packaged and decorated with more or less pure gold-like colors. Copper gold powder and the like are mostly used in the past gold pigments, but these products are not acid-resistant and have poor weather resistance, and are easily oxidized to lose luster. Therefore, gold pearlescent pigments are widely used as a special gold effect in place of the gold pearlescent pigments.

The golden pearlescent pigments sold on the market at present mostly focus on realizing golden color by adopting the combination of colorless titanium dioxide and red iron oxide, but the color concentration is limited, and the red color tone is stronger. With the increasingly high requirements of the market on the quality, the color, the brightness and the like of the golden pearlescent pigment, the research on the golden pearlescent pigment is deepened. The golden pearlescent pigment also has more and more complex structure, and is changed from the original single coating layer to the multi-coating layer, and the coating of the single metal oxide is changed into one or more combinations. For example, patent document CN 102127321 a describes a multi-layer coating and a preparation of gold pearlescent pigment in various metal oxide doped forms, which has the following structure: synthetic mica flakes/SnO₂*Al₂O₃/TiO₂/Fe₂O₃*ZnO/TiO₂. The patent document with publication number CN 104619785B forms a golden pearlescent pigment by designing an alternate coating with high and low refractive index oxides, and its structure is as follows: base material/Fe₂TiO₅-SiO₂-Fe₂TiO₅. The patent document CN 102250495B discloses a gold pearlescent pigment formed by alternately coating oxides with high and low refractive indexes, and doping aluminum element in tin oxide layer and vanadium element in iron oxide layer. The structure is as follows: substrate/SnO₂*Al₂O₃/TiO₂/SiO₂/Fe₂O₃*V₂O₃/TiO₂. Patent document CN 104870571 a describes a multi-layer coating and a preparation of gold pearlescent pigment in various metal oxide doped forms, which has the following structure: al (Al)₂O₃Flake + TiO₂*Fe₂O₃*Al₂O₃+SnO₂+TiO₂*Fe₂O₃*Al₂O₃. Patent document CN 102675931B describes the preparation of gold pearlescent pigments by multilayer oxide coating formation, which have the structure: synthetic mica flakes/SnO₂*TiO₂//Fe₂O₃*Al₂O₃/SnO₂*TiO₂。

Although the gold pearlescent pigment with high chroma and weak red tone can be prepared to a certain extent by adopting a structure of a multi-layer coating form and alternately coating high-low refractive oxide, a certain problem also exists, and the stability of the process is poor due to the sequence of hydrolysis pH values of the metal oxide in the multi-layer coating form.

In view of the above, the present invention is particularly proposed.

Disclosure of Invention

The first purpose of the invention is to provide a green phase golden pearlescent pigment based on synthetic mica, which uses the synthetic mica as a substrate, forms a plurality of non-uniform interfaces by alternately coating oxides with high and low refractive indexes, and controls the thickness of each coating layer of the bead to form the pearlescent pigment for enhancing chroma and brightness. In particular, the low-refraction coating layer is a composite oxide with colored low refractive index, and a cobalt oxide-doped titanium dioxide layer is adopted, so that the high-chroma green-phase gold pigment is obtained.

The second purpose of the invention is to provide a preparation method of the green-phase golden pearlescent pigment based on the synthetic mica, which adopts a multilayer-structured pearlescent pigment with high chroma and high brightness formed by alternately coating oxide layers with high and low refractive indexes, particularly emphasizes that a low refractive index layer adopts a colored absorption layer and is doped with an oxide layer with high refractive index, and has the advantages of convenience, simplicity, easy production and the like.

In order to achieve the above purpose of the present invention, the following technical solutions are adopted:

a green phase golden pearlescent pigment based on synthetic mica is characterized in that a mica substrate is coated with a tin oxide layer, a cobalt oxide doped titanium oxide layer, one of an iron oxide doped oxide layer, a magnesium fluoride layer or a magnesium silicate layer, a silicon oxide doped titanium oxide layer and an iron oxide layer in sequence;

preferably, the iron oxide layer is further coated with a protective layer, and more preferably, the protective layer is an organosilane coupling agent layer;

preferably, the mica substrate is fluorophlogopite;

preferably, the particle size of the mica substrate is 1 to 100. mu.m, more preferably 3 to 60 μm, still more preferably 5 to 45 μm;

preferably, the oxide is silica or alumina.

The high-refractive-index interlayer is formed by adopting a structure that oxides with high refractive indexes are coated alternately, and particularly, a non-ferrous metal oxide is doped in a low-refractive-index oxide layer to form a colored interlayer. In order to reduce the red hue, the coated titanium dioxide layer is doped with cobalt oxide, with the surprising result that a highly coloured, green-phase gold pigment is present.

Preferably, the refractive indices of the cobalt oxide doped titanium oxide layer, the silicon oxide doped titanium oxide layer and the iron oxide layer are greater than 1.8, more preferably greater than 2.5, still more preferably the refractive index is from 2.94 to 3.22, and still more preferably 3.01.

Preferably, the refractive index of the oxide layer, magnesium fluoride layer or magnesium silicate layer is less than 1.7, more preferably less than 1.6, even more preferably less than 1.5.

Preferably, the thickness of the cobalt oxide doped titanium oxide layer is 120-300nm, more preferably 120-280nm, still more preferably 130-270nm, still more preferably 150-250 nm.

Preferably, the thickness of the oxide layer, the magnesium fluoride layer or the magnesium silicate layer is 120-300nm, more preferably 130-270nm, still more preferably 150-250nm, and still more preferably 160-250 nm.

Preferably, the thickness of the silicon oxide doped titanium oxide layer is 50 to 350nm, more preferably 60 to 300nm, still more preferably 70 to 280nm, still more preferably 80 to 280 nm.

The preparation method of the green-phase golden pearlescent pigment based on the synthetic mica comprises the following steps:

(A) adding water into the synthetic mica to prepare slurry;

(B) adding water-soluble tin salt corresponding to tin oxide into the slurry prepared in the step (A), and coating a tin oxide layer through hydrolysis;

preferably, the pH of the hydrolysis is 1.5-3, more preferably 1.8;

(C) coating a cobalt oxide-doped titanium oxide layer on the tin oxide layer coated in the step (B);

preferably, the pH required for hydrolysis in step (C) is 1.5-3, more preferably 2.0;

(D) coating a silicon dioxide layer doped with ferric oxide on the cobalt oxide-doped titanium oxide layer coated in the step (C);

preferably, the pH required for hydrolysis in step (D) is 1.5 to 3, more preferably 3.0;

(E) coating the film layer coated in the step (D) with a silicon oxide-doped titanium oxide layer by hydrolysis using a water-soluble titanium salt and a silicate corresponding to titanium oxide and silicon oxide;

preferably, the pH of the hydrolysis is 1.5-3, more preferably 2.0;

(F) coating an iron oxide layer on the titanium oxide layer coated in the step (E), filtering, washing, drying and calcining to obtain the golden pearlescent pigment;

preferably, the pH required for hydrolysis in step (F) is 1.5 to 3, more preferably 3.0;

preferably, the temperature of the calcination is 700-850 ℃, more preferably 760-800 ℃;

preferably, in step (F), before filtration, an organosilane coupling agent layer having a thickness of 5 to 25nm is coated on the iron oxide layer;

more preferably, the method for coating an organosilane coupling agent layer specifically includes the steps of:

pulping the pearlescent pigment obtained in the step (F) with water to obtain pearlescent pigment slurry, heating to 70-90 ℃, preferably 75-80 ℃, adjusting the pH to 8.0-10.0, preferably 8.5-9.5, slowly adding 2-5% of sodium metasilicate pentahydrate relative to the weight of the pearlescent pigment, keeping the pH stable at 8.0-10.0, preferably 8.5-9.5 during the addition, reducing the pH to 5.0-7.0, preferably about 6.0-7.0, adding 0.1-0.5% of cerous nitrate and 0.1-0.3% of aluminum nitrate relative to the weight of the pearlescent pigment and fully stirring to reduce the pH to 5.0-7.0, preferably 6.0-7.0, adding 1-4%, preferably 2% of gamma-glycidyl ether oxypropyltrimethoxysilane and 1-4% relative to the weight of the pearlescent pigment, preferably 2% of 3-aminopropyltriethoxysilane, and stirring the resulting mixture sufficiently to obtain the organosilane coupling agent layer.

The green phase golden pearlescent pigment based on the synthetic mica is applied to the fields of paint, coating, plastics, leather coloring, wallpaper, powder coating and cosmetics.

Compared with the prior art, the invention has the beneficial effects that:

(1) according to the application, the iron oxide is doped with the silicon dioxide to form the colored low-refractive-index coating layer, so that the color concentration and brightness of pearly luster are obviously improved.

(2) The green-phase golden pearlescent pigment is obtained by doping the cobalt oxide with the titanium dioxide layer.

Detailed Description

The technical solutions of the present invention will be described clearly and completely with reference to the following detailed description, but those skilled in the art will understand that the following described examples are some, not all, of the examples of the present invention, and are only used for illustrating the present invention, and should not be construed as limiting the scope of the present invention. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention. The examples, in which specific conditions are not specified, were conducted under conventional conditions or conditions recommended by the manufacturer. The reagents or instruments used are not indicated by the manufacturer, and are all conventional products available commercially.

The green-phase gold pearlescent pigment based on the synthetic mica is characterized in that a mica substrate is coated with a tin oxide layer, a cobalt oxide-doped titanium oxide layer, one of an iron oxide-doped oxide layer, a magnesium fluoride layer or a magnesium silicate layer, a silicon oxide-doped titanium oxide layer and an iron oxide layer in sequence.

Wherein, the iron oxide-doped oxide layer, the magnesium fluoride layer or the magnesium silicate layer refers to one of the iron oxide-doped oxide layer, the iron oxide-doped magnesium fluoride layer or the iron oxide-doped magnesium silicate layer.

preferably, the mica substrate is fluorophlogopite;

preferably, the oxide is silica or alumina.

(A) adding water into the synthetic mica to prepare slurry;

preferably, the pH of the hydrolysis is 1.5-3, more preferably 1.8;

preferably, the pH of the hydrolysis is 1.5-3, more preferably 2.0;

Example 1

The green-phase golden pearlescent pigment provided by the application is characterized in that a fluorophlogopite substrate with the particle size of 20-100 microns (the average particle size is 50 microns) is coated with a tin oxide layer, a cobalt oxide-doped titanium oxide layer with the refractive index of more than 1.8 and the thickness of 120nm, an iron oxide-doped silicon dioxide layer with the refractive index of less than 1.7 and the thickness of 120nm, a silicon oxide-doped titanium oxide layer with the refractive index of more than 1.8 and the thickness of 50nm, an iron oxide layer with the refractive index of more than 1.8 and an organosilane coupling agent layer in sequence.

Example 2

The green-phase golden pearlescent pigment provided by the application is characterized in that a fluorophlogopite substrate with the particle size of 30-80 microns (the average particle size is 40 microns) is coated with a tin oxide layer, a cobalt oxide-doped titanium oxide layer with the refractive index of more than 2.5 and the thickness of 300nm, an iron oxide-doped aluminum oxide layer with the refractive index of less than 1.6 and the thickness of 300nm, a silicon oxide-doped titanium oxide layer with the refractive index of more than 2.5 and the thickness of 350nm, an iron oxide layer with the refractive index of more than 2.5 and an organosilane coupling agent layer in sequence.

Example 3

The green-phase golden pearlescent pigment provided by the application is characterized in that a fluorophlogopite substrate with the particle size of 20-100 microns (the average particle size is 50 microns) is coated with a tin oxide layer, a cobalt oxide-doped titanium oxide layer with the refractive index of 3.22 and the thickness of 120nm, a magnesium fluoride layer with the refractive index of less than 1.5 and the thickness of 130nm and doped with iron oxide, a silicon oxide-doped titanium oxide layer with the refractive index of 3.22 and the thickness of 60nm, an iron oxide layer with the refractive index of more than 3.22 and an organosilane coupling layer in sequence.

Example 4

The green-phase golden pearlescent pigment provided by the application is characterized in that a fluorophlogopite substrate with the particle size of 5-45 microns (the average particle size is 25 microns) is coated with a tin oxide layer, a cobalt oxide-doped titanium oxide layer with the refractive index of 2.94 and the thickness of 280nm, a magnesium fluoride layer with the refractive index of less than 1.5 and the thickness of 270nm and doped with iron oxide, a silicon oxide-doped titanium oxide layer with the refractive index of 2.94 and the thickness of 300nm, an iron oxide layer with the refractive index of more than 2.94 and an organosilane coupling layer in sequence.

Example 5

The green-phase golden pearlescent pigment provided by the application is characterized in that a fluorophlogopite substrate with the particle size of 10-60 micrometers (the average particle size is 30 micrometers) is coated with a tin oxide layer, a cobalt oxide-doped titanium oxide layer with the refractive index of 3.01 and the thickness of 250nm, a magnesium fluoride layer with the refractive index of less than 1.5 and the thickness of 250nm and doped with iron oxide, a silicon oxide-doped titanium oxide layer with the refractive index of 3.01 and the thickness of 280nm, an iron oxide layer with the refractive index of more than 3.01 and an organosilane coupling layer in sequence.

Example 6

The preparation method of the green-phase golden pearlescent pigment provided by the embodiment specifically comprises the following steps:

100g of fluorophlogopite with a particle size range of 5-45 μm (average particle size of 20 μm) was added to 2L of soft water with stirring, heated to 60 ℃ to adjust the pH of the solution to between 1.8, 100mL of a 2.5% aqueous solution of tin tetrachloride was added, the pH of the solution was maintained constant with a 30% NaOH solution for half an hour, then the temperature was raised to between 75-85 ℃ to adjust the pH of the solution to between 2.0, 500mL of a 2mol/L solution of titanium tetrachloride (containing 1% cobalt chloride) was added dropwise at a rate of 1mL/min to maintain the pH of the solution constant with a NaOH solution, then after raising the pH to 3.0, 600mL of a 20% sodium silicate solution was slowly metered in at this pH while controlling and maintaining the pH constant at 3.0 with a 10% iron trichloride solution. After the addition was completed and stirring was continued for half an hour, the pH was lowered to 2.0 with 1:1 hydrochloric acid, 400ml of 2mol/L titanium tetrachloride solution (containing 1% cobalt chloride) was slowly continued and the pH was kept constant with 30% sodium hydroxide solution, after the addition was completed and stirring was continued for half an hour, and then after the pH had increased to 3.0, 300ml of 10% ferric trichloride solution was slowly metered in and the pH was kept constant with 30% sodium hydroxide solution. Stirring for half an hour after adding, filtering, washing, drying at 110 deg.C for 12 hr, and calcining at 800 deg.C for 0.5 hr. The green phase golden pearlescent pigment is obtained.

Comparative example 1

100g of fluorophlogopite with a particle size range of 5-45 μm (average particle size of 20 μm) is added to 2L of soft water under stirring, heated to 60 ℃ to adjust the pH value of the solution to between 1.8, 100mL of a 2.5% aqueous solution of tin tetrachloride is added, the pH value of the solution is maintained constant with a 30% NaOH solution for half an hour, then the temperature is raised to between 75-85 ℃ to adjust the pH value of the solution to between 2.0, 500mL of a 2mol/L solution of titanium tetrachloride is added dropwise at a rate of 1mL/min to maintain the pH value of the solution constant with a NaOH solution, then after the pH is raised to 3.0, 600mL of a 20% sodium silicate solution is slowly metered in at this pH value while controlling and maintaining the pH value at 3.0 with a 10% iron trichloride solution. After the addition, the stirring was continued for half an hour, the pH was lowered to 2.0 with 1:1 hydrochloric acid, 400ml of 2mol/L titanium tetrachloride solution was continued slowly and the pH was kept constant with 30% sodium hydroxide solution, after the addition, the stirring was continued for half an hour, then the pH was raised to 3.0, 300ml of 10% ferric trichloride solution was slowly metered in, while the pH was kept constant with 30% sodium hydroxide solution. Stirring for half an hour after adding, filtering, washing, drying at 110 deg.C for 12 hr, and calcining at 800 deg.C for 0.5 hr. The golden pearlescent pigment is obtained.

Comparative example 2

100g of fluorophlogopite with a particle size range of 5-45 μm (average particle size of 20 μm) is added to 2L of soft water under stirring, heated to 60 ℃ to adjust the pH of the solution to between 1.8, 100mL of a 2.5% aqueous solution of tin tetrachloride is added, the pH of the solution is maintained constant with a 30% NaOH solution for half an hour, then the temperature is raised to between 75-85 ℃ to adjust the pH of the solution to between 2.0, 500mL of a 2mol/L solution of titanium tetrachloride is added dropwise at a rate of 1mL/min to maintain the pH of the solution constant with a NaOH solution, then after the pH is raised to 8.0, 600mL of a 20% sodium silicate solution is slowly metered in at this pH while controlling and maintaining the pH at 8.0 with a 10% hydrochloric acid solution. After the addition was completed and stirring was continued for half an hour, the pH was lowered to 2.0 with 1:1 hydrochloric acid, 400ml of a 2mol/L titanium tetrachloride solution was continued slowly and the pH was kept constant with 30% sodium hydroxide solution, after the addition was completed and stirring was continued for half an hour, then the pH was raised to 3.0, 300ml of a 10% ferric trichloride solution was slowly metered in and the pH was kept constant with 30% sodium hydroxide solution. And after the addition is finished, continuing stirring for half an hour, filtering, washing, drying at 110 ℃ for 12 hours, and finally calcining at 800 ℃ for 0.5 hour to obtain the golden pearlescent pigment.

Experimental examples pigment Performance evaluation

The properties of the pigments provided in example 6 and comparative examples 1-2 were evaluated using a conventional method of coating a scratch card or a spray board. Adding a certain pearlescent pigment into resin or paint, stirring uniformly, coating or spraying a plate, and testing the color and the smoothness by using an X-Rite MA68 color difference instrument. The evaluation results are shown in table 1.

TABLE 1 evaluation results of pigment Properties

Wherein L is brightness, a and b are colors, c is color saturation, and h is color angle.

The experimental results show that compared with the prior art processes adopted in comparative examples 1 and 2, the preparation process provided in example 6 has the advantages that the color concentration and brightness of the golden pearly luster obtained by adopting the iron oxide doped silicon dioxide as the intermediate interlayer structure are obviously improved, and the red tone is lighter. Example while using a colored interlayer, it was unexpected that doping the titanium dioxide layer with cobalt oxide resulted in a highly colored, greenish-phase, gold-colored pearlescent.

Application examples

The pearlescent pigments of the above embodiments can be applied to the fields of paints, coatings, plastics, leather coloring, wallpaper, powder coatings, cosmetics and the like. For example, the addition of the pearlescent pigments of the present invention to paints or plastics can exhibit very excellent color and color effects.

Application example 1: taking paint spraying as an example

4.00 grams of the pearlescent pigment of example 1 was accurately weighed, 4.0 grams of butyl acetate and 8.0 grams of polyester automotive coating resin were added, placed under a stirrer and stirred for 10 minutes, and 84.0 grams of the automotive coating resin system was added and stirred for 5 minutes. The viscosity of the coating was adjusted to 14-15 seconds for Ford 4 cup before spraying. And during spraying, the temperature of a spraying room is controlled to be 25 ℃, and the relative humidity is controlled to be 60%. Spraying twice, flashing for 10 minutes, covering with varnish, flashing again, and baking at 140 ℃ for 30 minutes.

Application example 2: taking injection molding applications as an example

200 g of polypropylene (PP) material dried at 105 ℃ is accurately weighed into a plastic sealing bag, 1ml of gloss oil (also called dispersing oil) is added, and then the mixture is shaken to fully mix the gloss oil and the polypropylene material. 4.000 g of the pearl essence of example 1 was weighed into a plastic sealed bag using an analytical balance preparation, and shaken and kneaded again to disperse the pearl essence in the PP pellets sufficiently and uniformly. After the temperature of the charging barrel reaches a set value (usually 180-200 ℃), adding the prepared polypropylene material into a hopper, extruding the original residual material in the charging barrel by using the functions of injecting glue and melting glue until a new material is extruded, wherein the extruded new material has luster, no impurities, no black spots, no scorching and no bubbles; meanwhile, the nozzle is not blocked during glue injection. After the front and the rear plastic sheets are not different, the produced plastic sheets are stable and qualified products, and can enter automatic normal production.

While particular embodiments of the present invention have been illustrated and described, it will be appreciated that the above embodiments are merely illustrative of the technical solution of the present invention and are not restrictive; those of ordinary skill in the art will understand that: modifications may be made to the above-described embodiments, or equivalents may be substituted for some or all of the features thereof without departing from the spirit and scope of the present invention; the modifications or the substitutions do not make the essence of the corresponding technical solutions depart from the scope of the technical solutions of the embodiments of the present invention; it is therefore intended to cover in the appended claims all such alternatives and modifications that are within the scope of the invention.

Claims

1. The green-phase gold pearlescent pigment based on the synthetic mica is characterized in that a mica substrate is coated with a tin oxide layer, a cobalt oxide-doped titanium oxide layer, one of an iron oxide-doped oxide layer, a magnesium fluoride layer or a magnesium silicate layer, a silicon oxide-doped titanium oxide layer and an iron oxide layer in sequence.

2. The synthetic mica-based green phase gold pearlescent pigment of claim 1, wherein the iron oxide layer is further coated with a protective layer.

3. The synthetic mica-based green-phase gold pearlescent pigment of claim 2, wherein the protective layer is an organosilane coupling agent layer.

4. The synthetic mica-based green phase gold pearlescent pigment of claim 1, wherein the mica substrate is fluorophlogopite.

5. The synthetic mica-based green phase gold pearlescent pigment of claim 1, wherein the particle size of the mica substrate is 1 to 100 μm.

6. The synthetic mica-based green phase gold pearlescent pigment of claim 1, wherein the particle size of the mica substrate is 3 to 60 μm.

7. A green phase gold pearlescent pigment based on synthetic mica according to claim 1, characterized in that the particle size of the mica substrate is 5 to 45 μm.

8. The synthetic mica-based green phase gold pearlescent pigment of claim 1, wherein the oxide is silica or alumina.

9. The synthetic mica-based green phase gold pearlescent pigment of claim 1, wherein the cobalt oxide-doped titanium oxide layer, the silicon oxide-doped titanium oxide layer and the iron oxide layer have a refractive index of greater than 1.8.

10. The synthetic mica-based green phase gold pearlescent pigment of claim 1, wherein the cobalt oxide-doped titanium oxide layer, the silicon oxide-doped titanium oxide layer and the iron oxide layer have a refractive index of greater than 2.5.

11. The synthetic mica-based green phase gold pearlescent pigment of claim 1, wherein the cobalt oxide-doped titanium oxide layer, the silicon oxide-doped titanium oxide layer and the iron oxide layer have a refractive index of 2.94-3.22.

12. The synthetic mica-based green phase gold pearlescent pigment of claim 1, wherein the cobalt oxide-doped titanium oxide layer, the silicon oxide-doped titanium oxide layer and the iron oxide layer have a refractive index of 3.01.

13. The synthetic mica-based green phase gold pearlescent pigment of claim 1, wherein the oxide layer, magnesium fluoride layer or magnesium silicate layer has a refractive index of less than 1.7.

14. The synthetic mica-based green phase gold pearlescent pigment of claim 1, wherein the oxide layer, magnesium fluoride layer or magnesium silicate layer has a refractive index of less than 1.6.

15. The synthetic mica-based green phase gold pearlescent pigment of claim 1, wherein the oxide layer, magnesium fluoride layer or magnesium silicate layer has a refractive index of less than 1.5.

16. The synthetic mica-based green phase gold pearlescent pigment of claim 1, wherein the cobalt oxide-doped titanium oxide layer has a thickness of 120-300 nm.

17. The synthetic mica-based green phase gold pearlescent pigment of claim 1, wherein the cobalt oxide-doped titanium oxide layer has a thickness of 120-280 nm.

18. The synthetic mica-based green phase gold pearlescent pigment of claim 1, wherein the cobalt oxide-doped titanium oxide layer has a thickness of 150-250 nm.

19. The synthetic mica-based green phase gold pearlescent pigment of claim 1, wherein the thickness of the oxide layer, magnesium fluoride layer or magnesium silicate layer is 120-300 nm.

20. The green phase gold pearlescent pigment based on synthetic mica of claim 1, characterized in that the thickness of the oxide layer, magnesium fluoride layer or magnesium silicate layer is 130-270 nm.

21. The synthetic mica-based green phase gold pearlescent pigment of claim 1, wherein the thickness of the oxide layer, magnesium fluoride layer or magnesium silicate layer is 150-250 nm.

22. The green phase gold pearlescent pigment based on synthetic mica of claim 1, wherein the thickness of the oxide layer, magnesium fluoride layer or magnesium silicate layer is 160-250 nm.

23. The synthetic mica-based green phase gold pearlescent pigment of claim 1, wherein the thickness of the silicon oxide-doped titanium oxide layer is 50-350 nm.

24. The synthetic mica-based green phase gold pearlescent pigment of claim 1, wherein the thickness of the silicon oxide-doped titanium oxide layer is 60-300 nm.

25. The synthetic mica-based green phase gold pearlescent pigment of claim 1, wherein the thickness of the silicon oxide-doped titanium oxide layer is 70-280 nm.

26. The synthetic mica-based green phase gold pearlescent pigment of claim 1, wherein the thickness of the silicon oxide-doped titanium oxide layer is 80-280 nm.

27. The method for preparing a green phase gold pearl pigment based on synthetic mica according to any one of claims 1 to 26, which comprises the steps of:

(A) adding water into the synthetic mica to prepare slurry;

(F) and (E) coating an iron oxide layer on the titanium oxide layer coated in the step (E), filtering, washing, drying and calcining to obtain the green-phase golden pearlescent pigment.

28. The method for preparing a green-phase gold pearl pigment according to claim 27, wherein in the step (B), the pH of the hydrolysis is 1.5 to 3.

29. The method for preparing a green-phase gold pearl pigment according to claim 27, wherein in the step (B), the pH of the hydrolysis is 1.8.

30. The method for preparing a green-phase gold pearl pigment according to claim 27, wherein in the step (C), the pH of the step (C) is 1.5 to 3.

31. The method for preparing a green-phase gold pearl pigment according to claim 27, wherein in the step (C), the pH of the step (C) is 2.0.

32. The method for preparing a green-phase gold pearl pigment according to claim 27, wherein in the step (D), pH required for the hydrolysis in the step (D) is 1.5 to 3.

33. The method for preparing a green-phase gold pearl pigment according to claim 27, wherein in the step (D), pH required for the hydrolysis in the step (D) is 3.0.

34. The method for preparing a green-phase gold pearl pigment according to claim 27, wherein in the step (E), the pH of the hydrolysis is 1.5 to 3.

35. The method for preparing a green-phase gold pearl pigment according to claim 27, wherein in the step (E), the pH of the hydrolysis is 2.0.

36. The method for preparing a green-phase gold pearl pigment according to claim 27, wherein in the step (F), pH required for the hydrolysis in the step (F) is 1.5 to 3.

37. The method for preparing a green-phase gold pearl pigment according to claim 27, wherein in the step (F), the pH required for the hydrolysis in the step (F) is 3.0.

38. The method for preparing a green phase gold pearl pigment based on synthetic mica according to claim 27, wherein the temperature of the calcination in the step (F) is 700-850 ℃.

39. The method for preparing a green phase gold pearl pigment based on synthetic mica according to claim 27, wherein the temperature of the calcination in the step (F) is 760-800 ℃.

40. The method of producing a green-phase gold pearl pigment according to claim 27, wherein in the step (F), before the filtration, an organosilane coupling agent layer having a thickness of 5 to 25nm is coated on the iron oxide layer.

41. The method for preparing a green-phase gold pearlescent pigment based on synthetic mica according to claim 40, wherein the method for coating the organosilane coupling agent layer comprises the following steps:

adding water into the pearlescent pigment obtained in the step (F) for pulping to obtain pearlescent pigment slurry, heating to 70-90 ℃, adjusting the pH to 8.0-10.0, slowly adding sodium metasilicate pentahydrate accounting for 2% -5% of the weight of the pearlescent pigment, keeping the pH at 8.0-10.0 in the adding process, reducing the pH to 5.0-7.0 after the adding is finished, adding cerium nitrate accounting for 0.1% -0.5% of the weight of the pearlescent pigment and aluminum nitrate accounting for 0.1% -0.3% of the weight of the pearlescent pigment, fully stirring, reducing the pH to 5.0-7.0, adding gamma-glycidyl ether oxypropyltrimethoxysilane accounting for 1% -4% of the weight of the pearlescent pigment and 3-aminopropyltriethoxysilane accounting for 1% -4% of the weight of the pearlescent pigment, and fully stirring to obtain the organosilane coupling agent layer.

42. The method for preparing a green phase gold pearl pigment based on synthetic mica according to claim 41, wherein said temperature is raised to 75 to 80 ℃.

43. The method for preparing a green phase gold pearl pigment according to claim 41, wherein said pH is adjusted to 8.5 to 9.5 in the process of adjusting pH.

44. The method for preparing a green phase golden pearlescent pigment based on synthetic mica according to claim 41, wherein the pH is kept stable at 8.5-9.5 in the process of keeping the pH stable during the addition.

45. The method for preparing a green phase gold pearl pigment according to claim 41, wherein said pH is lowered to 6.0 to 7.0 after the completion of the pH lowering.

46. The method for preparing a green phase gold pearl pigment according to claim 41, wherein said step of lowering the pH to 5.0 to 7.0, specifically, 6.0 to 7.0.

47. The method for preparing a green phase gold pearlescent pigment based on synthetic mica according to claim 41, wherein the amount of the gamma-glycidoxypropyltrimethoxysilane added is 2% by weight of the pearlescent pigment.

48. The method for preparing a green gold pearlescent pigment based on synthetic mica according to claim 41, wherein the amount of 3-aminopropyltriethoxysilane added is 2% by weight of the pearlescent pigment.

49. Use of the green phase gold pearlescent pigment based on synthetic mica according to any one of claims 1 to 26 in the fields of paints, coatings, plastics, leather coloring, wallpaper, cosmetics.