CN111410851A

CN111410851A - Blue pearlescent pigment and preparation method and application thereof

Info

Publication number: CN111410851A
Application number: CN202010239016.3A
Authority: CN
Inventors: 费明; 武超; 鲍领翔; 陈刘; 谢秉昆
Original assignee: Fujian Kuncai Material Technology Co ltd
Current assignee: Fujian Kuncai Material Technology Co ltd
Priority date: 2020-03-30
Filing date: 2020-03-30
Publication date: 2020-07-14

Abstract

The invention discloses a blue pearlescent pigment and a preparation method and application thereof, and relates to the technical field of pearlescent pigments.

Description

Blue pearlescent pigment and preparation method and application thereof

Technical Field

The invention relates to the technical field of pearlescent pigments, and particularly relates to a blue pearlescent pigment and a preparation method and application thereof.

Background

Blue is a color, has a high frequency (next to blue-violet light) in visible light of electromagnetic waves, has a frequency of 600 to 660THz (corresponding to a wavelength of 500 to 450nm in air), and belongs to high-frequency light. It is beautiful, cool, smart, easy and extensive. Because of the property of blue color stability and the intelligent and accurate image, in commercial design, the commercial products or enterprise images with emphasis on science and technology and efficiency are mostly selected from blue, such as computers, automobiles, photocopiers, photographic equipment and the like, so that blue pigments are widely favored, especially blue pearlescent pigments.

Currently, blue pearlescent pigments are mainly of the following classes:

firstly, interference blue mica titanium pearlescent pigment is a product formed by coating a titanium dioxide single layer or alternatively coating titanium dioxide/silicon oxide on a flaky substrate, the interference color of the main light of the product is blue, and the powder is colorless;

secondly, the prussian blue is coated on the sheet-shaped substrate to form a product, and the product has the defects that the prussian blue is decomposed at the temperature of 200-300 ℃ and is easy to dissolve in alkali (such as US3957619 and CN 102443285B);

thirdly, some blue organic pigments are adsorbed on the flaky base materials, and the defects of easy shedding, color migration and insufficient temperature resistance are overcome (such as US 4968351);

fourthly, the outermost (or innermost) coating of cobalt aluminate on the platelet substrate must increase the blue effect, but the amount of coating is limited, too little without blue effect, too much affecting the pearlescent qualities (e.g. CN104804475B, CN1160423C and US 5169442).

In view of this, the invention is particularly proposed.

Disclosure of Invention

The invention aims to provide a blue pearlescent pigment and a preparation method thereof.

The invention is realized by the following steps:

in a first aspect, embodiments provide a blue pearlescent pigment, which comprises a substrate and a composite coating coated on the surface of the substrate; the composite coating comprises from bottom to top: a first high refractive index layer, a cobalt aluminate layer, a low refractive index layer, and a second high refractive index layer.

In a second aspect, embodiments provide a method of preparing a blue pearlescent pigment as described in the previous embodiments, comprising reacting materials for synthesizing the high refractive index layer, the cobalt aluminate layer and the low refractive index layer, respectively, in a system comprising a substrate to sequentially coat the substrate with the first high refractive index layer, the cobalt aluminate layer, the low refractive index layer and the second high refractive index layer.

In a third aspect, embodiments provide the use of the blue pearlescent pigment of the above embodiments or the blue pearlescent pigment prepared by the preparation method of the foregoing embodiments in paint, plastic, leather or wallpaper.

In a fourth aspect, embodiments provide a coating comprising the blue pearlescent pigment of the foregoing examples or prepared by the preparation method of the foregoing examples.

In a fifth aspect, embodiments provide an article of manufacture comprising a blue pearlescent pigment as described in the preceding examples or prepared by the preparation methods described in the preceding examples.

The invention has the following beneficial effects:

the embodiment of the invention provides a blue pearlescent pigment and a preparation method thereof, the pigment is a multilayer coated high-low high-refractive index structure, cobalt aluminate is used as an interlayer with a middle low refractive index, the problems of no temperature resistance, color migration, poor coloring power and the like in the preparation of the blue pearlescent pigment in the prior art are solved, the pearlescent pigment with high chroma and high gloss is provided, and the powder is blue.

Drawings

In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings needed to be used in the embodiments will be briefly described below, it should be understood that the following drawings only illustrate some embodiments of the present invention and therefore should not be considered as limiting the scope, and for those skilled in the art, other related drawings can be obtained according to the drawings without inventive efforts.

FIG. 1 is a schematic representation of the effect of a spray application of a blue pearlescent pigment in application example 1 of the present invention;

FIG. 2 is a schematic representation of the effect of the injection molding application of the blue pearlescent pigment of application example 2 of the present invention.

Detailed Description

In order to make the objects, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below. 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.

Noun definitions

As referred to herein, "high refractive index" refers to a material having a refractive index that is the same as or similar to the refractive index of tin oxide and/or titanium oxide.

Reference herein to "low refractive index" is to a material having a refractive index that is the same as or similar to the refractive index of silica and/or alumina.

As referred to herein "the composite coating comprises from bottom to top: the first high refractive index layer, the cobalt aluminate layer, the low refractive index layer and the second high refractive index layer from bottom to top mean that the first high refractive index layer is coated on the surface of the base material, the cobalt aluminate layer is coated on the first high refractive index layer, and the like.

Specific embodiments of the present application.

Firstly, the embodiment provides a blue pearlescent pigment, which comprises a substrate and a composite coating coated on the surface of the substrate;

the composite coating comprises from bottom to top: a first high refractive index layer, a cobalt aluminate layer, a low refractive index layer, and a second high refractive index layer.

The research of the inventor finds that the blue pearlescent pigment with high chroma and high gloss is formed by taking cobalt aluminate as an interlayer with middle low refractive index and adopting a multi-layer coating structure. Compared with the traditional inorganic blue pigment, such as cobalt blue (cobalt phosphate), and the pearlescent pigment coated by organic/inorganic pigments (prussian blue, cobalt blue, ultramarine blue, phthalocyanine and the like), the blue pearlescent pigment provided by the embodiment of the application has bright color and luster, and has better high-temperature resistance, color fastness and glossiness.

In an optional embodiment, the first high refractive index layer has a thickness of 20 to 50nm, the cobalt aluminate layer has a thickness of 50 to 100nm, the low refractive index layer has a thickness of 10 to 30nm, and the second high refractive index layer has a thickness of 20 to 50 nm.

In an alternative embodiment, the first high refractive index layer and the second high refractive index layer are both coatings composed of transparent or translucent high refractive index materials.

Preferably, the high refractive index material is selected from any one or more of titanium oxide, zirconium oxide and tin oxide.

Preferably, the high refractive index material is titanium oxide.

Preferably, the high refractive index material is tin oxide and titanium oxide.

Preferably, in the high refractive index material, the content of tin oxide is 1 to 3% of titanium oxide.

In an alternative embodiment, the low refractive index layer is a coating consisting of a colorless transparent material of the low refractive index material. The low-refractive-index layer mainly plays a role in isolating and protecting the cobalt aluminate layer, and the cobalt aluminate layer is prevented from being damaged by an acid system of the high-refractive-index layer (the pH value is 1.5-2.0) to influence the surface of the film layer. The content of the low refractive index layer is 3-6% of the base material; preferably 5%.

Preferably, the low refractive index material is silicon dioxide.

In an alternative embodiment, the substrate is a sheet substrate.

Preferably, the substrate is selected from one or more of natural mica, synthetic mica, glass flakes and alumina.

Preferably, the particle size of the base material is 5-100 μm.

Preferably, the particle size of the base material is 10-40 μm.

Preferably, the embodiment provides a blue pearlescent pigment with the structure:

synthetic mica + TiO₂+Co(AlO₂)+SiO₂+TiO₂(ii) a Or:

synthetic mica + SnO/TiO₂+Co(AlO₂)+SiO₂+SnO/TiO₂。

The embodiment provides a preparation method of the blue pearlescent pigment, which comprises the step of reacting materials respectively used for synthesizing the high refractive index layer, the cobalt aluminate layer and the low refractive index layer in a system containing a substrate so as to sequentially coat the first high refractive index layer, the cobalt aluminate layer, the low refractive index layer and the second high refractive index layer on the substrate.

In an alternative embodiment, the cladding process of the first high refractive index layer is: hydrolyzing a solution containing a high-refractive-index material in a system containing a base material at the temperature of 55-78 ℃ and the pH value of 1.5-2.0 until the surface of the base material is coated with a first high-refractive-index layer.

Preferably, the solution containing the high refractive index material is a solution of titanium tetrachloride.

Preferably, the solution containing a high refractive index material is a titanium tetrachloride solution containing tin tetrachloride.

Preferably, the content of the tin tetrachloride in the titanium tetrachloride solution is 1-3% of the mass of the titanium tetrachloride.

In an alternative embodiment, the cladding process of the cobalt aluminate layer is: and hydrolyzing a solution of a material for synthesizing the cobalt aluminate layer in a system containing the substrate coated with the first high-refractive-index layer at the temperature of 75-85 ℃ and the pH value of 6.5-7.5 until the surface of the first high-refractive-index layer of the substrate is coated with the cobalt aluminate layer.

Preferably, the solution of the material for synthesizing the cobalt aluminate layer is a mixed solution of aluminum chloride and cobalt chloride.

Preferably, in the mixed solution of aluminum chloride and cobalt chloride, the molar ratio of aluminum to cobalt is (2-4): 1. preferably 2.5: 1.

in an alternative embodiment, the cladding process of the low refractive index layer is: in a system containing a base material coated with a cobalt aluminate layer, under the conditions that the temperature is 75-85 ℃ and the pH value is 6.5-7.5, a solution containing a low-refractive-index material is hydrolyzed, and the surface of the cobalt aluminate layer of the high base material is coated with the low-refractive-index layer.

The "substrate containing a coated cobalt aluminate layer" refers to a substrate having a high refractive index layer and a cobalt aluminate layer sequentially coated on the surface thereof.

Preferably, the solution of the low refractive index material is sodium metasilicate.

In an alternative embodiment, the cladding process of the second high refractive index layer is: in a system containing a base material coated with a low refractive index layer, under the conditions that the temperature is 55-78 ℃ and the pH value is 1.5-2.0, a solution containing a high refractive index material is hydrolyzed until the surface of the low refractive index layer of the base material is coated with a second high refractive index layer.

As above, "the substrate coated with the low refractive index layer" means a substrate whose surface is sequentially coated with the first high refractive index layer, the cobalt aluminate layer, and the low refractive index layer.

In an alternative embodiment, after the first high refractive index layer, the cobalt aluminate layer, the low refractive index layer and the second high refractive index layer are coated on the surface of the substrate, the substrate coated with the composite coating is dried and calcined.

Preferably, the drying time is 10-14 h, and the drying temperature is 100-120 ℃.

Preferably, the calcining time is 20-40 min, and the calcining temperature is 800-1000 ℃.

The embodiments also provide for the use of a blue pearlescent pigment according to any preceding embodiment or a blue pearlescent pigment prepared according to the preparation method according to any preceding embodiment in coatings, plastics, leather or wallpaper.

The embodiments also provide a coating comprising a binder and the blue pearlescent pigment of any preceding embodiment or the blue pearlescent pigment prepared by the preparation method of any preceding embodiment.

In an alternative embodiment, the binder is a resin selected from any one of rosin resin, alkyd resin, phenolic resin, amino resin, polyester resin, acrylic resin, epoxy resin, silicone resin, and fluorocarbon resin. Additionally, embodiments also provide an article of manufacture comprising the blue pearlescent pigment of any of the preceding embodiments or the blue pearlescent pigment prepared by the preparation method of any of the preceding embodiments.

Preferably, the article is selected from plastic, leather or wallpaper.

The features and properties of the present invention are described in further detail below with reference to examples.

Example 1

This example provides a method for preparing a blue pearlescent pigment, which includes the following steps:

(1) first high refractive index layer:

under the condition of stirring, 100g of synthetic mica with the particle size range of 5-45 mu m (the average particle size is 27 mu m) is added into 2L soft water and heated to 78 ℃;

the pH value of the system containing the synthetic mica is reduced to 1.5 by using a hydrochloric acid solution with the mass fraction of 15%, a titanium tetrachloride solution (containing 1.5 percent of stannic chloride) with the mass fraction of 300m L is added for hydrolysis, a sodium hydroxide solution with the mass fraction of 30 percent is used for maintaining the pH value of the solution unchanged, and the stirring is continued for 30min after the addition is finished.

(2) Cobalt aluminate layer:

and (2) raising the pH value of the system coated with the first high-refractive-index layer obtained in the step (1) to 6.5, continuously and slowly hydrolyzing 1500m L of a mixed solution containing aluminum trichloride and cobalt chloride (the mass ratio of the aluminum trichloride to the cobalt chloride is 120g/30g), controlling and keeping the pH value at 6.5 by using 30% sodium hydroxide, maintaining the temperature at 80 ℃, and continuously stirring for half an hour after the addition is finished.

(3) Low refractive index layer:

in a system of a base material coated with a cobalt aluminate layer, under the conditions that the temperature is 80 ℃ and the pH is 6.5, continuously adding 200m L10% sodium metasilicate solution, keeping the pH unchanged by hydrochloric acid, and continuously stirring for half an hour after the addition is finished.

(4) Second high refractive index layer:

in the system of the substrate coated with the low refractive index layer, the pH of the system was then adjusted to 1.5, and 300ml of titanium tetrachloride solution (containing 1.5% of tin tetrachloride) was continuously and slowly added for hydrolysis, and the pH was kept constant with 30% sodium hydroxide solution.

And after the reaction is finished, filtering and washing the substrate coated with the composite coating, drying at 110 ℃ for 12h, and finally calcining at 800 ℃ for 0.5 h to obtain the blue pearlescent pigment.

Example 2

This example provides a method for preparing a blue pearlescent pigment, which is substantially the same as in example 1, except for the differences in the parameters, as follows.

(1) First high refractive index layer:

under the condition of stirring, 100g of synthetic mica with the particle size range of 10-30 mu m (the average particle size is 27 mu m) is added into 2L soft water and heated to 78 ℃;

the pH of the system containing the synthetic mica was lowered to 1.5 with hydrochloric acid solution, and 400m L titanium tetrachloride solution (containing 1.5% tin tetrachloride) was added for hydrolysis, and 30% sodium hydroxide solution was used to maintain the pH of the solution constant, and stirring was continued for 30min after the addition.

(2) Cobalt aluminate layer:

and (2) raising the pH value of the system coated with the first high-refractive-index layer obtained in the step (1) to 6.5, continuously and slowly hydrolyzing 2000m L of a mixed solution containing aluminum trichloride and cobalt chloride (the mass ratio of the aluminum trichloride to the cobalt chloride is 160g/40g), controlling and keeping the pH value at 6.5 by using 30% sodium hydroxide, maintaining the temperature at 80 ℃, and continuously stirring for 30min after the addition is finished.

(3) Low refractive index layer:

(4) Second high refractive index layer:

in the system of the substrate coated with the low refractive index layer, the pH of the system was then adjusted to 1.5, and 350m L titanium tetrachloride solution (containing 1.5% tin tetrachloride) was continuously and slowly added to hydrolyze the substrate, and the pH was kept constant with 30% sodium hydroxide solution.

Comparative example 1

Comparative example provides a method for preparing a blue pearlescent pigment, which is substantially the same as example 1 except that the composite coating layer is provided with a different structure, and the composite coating layer of comparative example 1 omits the coating of the high refractive index 2.

Comparative example 2

Comparative example provides a method for preparing a blue pearlescent pigment, which is substantially the same as example 1 except that the composite coating layer is provided with a different structure, and the composite coating layer of comparative example 1 omits the coating of high refractive index 1.

Comparative example 3

Comparative example a method for preparing a blue pearlescent pigment was provided, which was substantially the same as example 1 except that the arrangement structure of the composite coating layer was different, and in comparative example 1, the first high refractive index layer of example 1 was exchanged with the cobalt aluminate layer.

Comparative example 4

Comparative example a method for preparing a blue pearl pigment, which is substantially the same as example 1 except that the arrangement structure of the composite coating layer is different, was provided, and in comparative example 1, the cobalt aluminate layer and the low refractive index layer in example 1 were exchanged.

Application example 1

Paint spraying is taken as an example.

4.00g of blue pearlescent pigment (prepared by the preparation methods described in examples 1-2 and comparative examples 1-4), 4.0g of butyl acetate and 8.0g of polyester automotive coating resin were mixed, stirred and dispersed for 10 minutes in a stirrer, and 84.0g of the automotive coating resin system was added and stirred for 5 minutes.

Before spraying, the viscosity of the coating is adjusted to 15s of a Ford 4 cup. The temperature of the spraying room is controlled to be 25 ℃ and the relative humidity is controlled to be 60 percent during spraying. Spraying twice, flashing for 10min, covering with varnish, flashing again, and baking at 140 deg.C for 30 min.

The color and finish were measured again using an X-Rite MA68 color difference meter, and the results are shown in Table 1. FIG. 1 is a schematic representation of the effect of the spray application of blue pearlescent pigment provided in example 1 of the present application.

TABLE 1 color data from colorimeter

Note that in Table 1, h ° represents the hue angle, C ° represents the saturation, L ° represents the lightness a yellow and green, and b represents red and blue.

As can be seen from Table 1, the pigments provided in examples 1-2 are significantly improved in both color saturation and brightness as compared to comparative examples 1-4.

Application example 2

Take injection molding applications as an example.

200g of polypropylene (PP) dried at 105 ℃ is accurately weighed in a plastic sealed bag, 1m of L gloss oil (also called dispersing oil) is added and then oscillated to fully mix the gloss oil and the polypropylene, 4.00g of blue pearlescent pigment (the blue pearlescent pigment prepared in example 1) is weighed in an analytical balance and added in the plastic sealed bag, and the mixture is oscillated and kneaded again to fully and uniformly disperse the pearlescent powder in PP particles.

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 back plastic sheets (please refer to fig. 2) are not different, the produced plastic sheets are stable and qualified products, and can enter into automatic normal production.

The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention, and various modifications and changes may be made by those skilled in the art. Any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. The blue pearlescent pigment is characterized by comprising a substrate and a composite coating coated on the surface of the substrate;

2. The blue pearl pigment according to claim 1, wherein the thickness of the first high refractive index layer is 20 to 50nm, the thickness of the cobalt aluminate layer is 50 to 100nm, the thickness of the low refractive index layer is 10 to 30nm, and the thickness of the second high refractive index layer is 20 to 50 nm;

preferably, the first high refractive index layer and the second high refractive index layer are both coatings composed of transparent or translucent high refractive index materials;

preferably, the high refractive index material is selected from any one or more of titanium oxide, zirconium oxide and tin oxide;

preferably, the high refractive index material is titanium oxide;

preferably, the high refractive index material is tin oxide and titanium oxide;

3. The blue pearlescent pigment of claim 2, wherein the low refractive index layer is a coating layer composed of a colorless transparent material of a low refractive index material;

preferably, the low refractive index material is silicon dioxide;

preferably, the substrate is a sheet-like substrate;

preferably, the substrate is selected from one or more of natural mica, synthetic mica, glass flakes and alumina;

preferably, the particle size of the base material is 5-100 μm.

4. The method for producing a blue pearl pigment according to claim 1, which comprises: materials respectively used for synthesizing the high refractive index layer, the cobalt aluminate layer and the low refractive index layer are reacted in a system containing a base material, so that the base material is sequentially coated with the first high refractive index layer, the cobalt aluminate layer, the low refractive index layer and the second high refractive index layer.

5. The method for preparing a blue pearlescent pigment according to claim 4, wherein the coating process of the first high refractive index layer is: hydrolyzing a solution containing a high-refractive-index material in a system containing a base material at the temperature of 55-78 ℃ and the pH value of 1.5-2.0 until the surface of the base material is coated with a first high-refractive-index layer;

preferably, the solution containing the high refractive index material is a solution of titanium tetrachloride;

preferably, the solution containing a high refractive index material is a titanium tetrachloride solution containing tin tetrachloride;

6. The method for preparing blue pearlescent pigment according to claim 5, wherein the coating process of the cobalt aluminate layer is as follows: hydrolyzing a solution of a material for synthesizing the cobalt aluminate layer in a system containing the base material coated with the first high-refractive-index layer at the temperature of 75-85 ℃ and the pH value of 6.5-7.5 until the surface of the first high-refractive-index layer of the base material is coated with the cobalt aluminate layer;

preferably, the solution of the material for synthesizing the cobalt aluminate layer is a mixed solution of aluminum chloride and cobalt chloride;

preferably, in the mixed solution of aluminum chloride and cobalt chloride, the molar ratio of aluminum to cobalt is (2-4): 1.

7. the method for preparing a blue pearlescent pigment according to claim 6, wherein the coating process of the low refractive index layer is as follows: hydrolyzing a solution of a low-refractive-index material in a system containing a base material coated with a cobalt aluminate layer at the temperature of 75-85 ℃ and the pH value of 6.5-7.5 to coat the low-refractive-index layer on the surface of the cobalt aluminate layer of the high base material;

preferably, the solution of the low refractive index material is sodium metasilicate;

preferably, the cladding process of the second high refractive index layer is: in a system containing a base material coated with a low refractive index layer, under the conditions that the temperature is 55-78 ℃ and the pH value is 1.5-2.0, a solution containing a high refractive index material is hydrolyzed until the surface of the low refractive index layer of the base material is coated with a second high refractive index layer.

8. Use of the blue pearlescent pigment of any one of claims 1 to 3 or the blue pearlescent pigment prepared by the method of any one of claims 4 to 7 in coatings, plastics, leather or wallpaper.

9. A paint comprising a binder and the blue pearlescent pigment according to any one of claims 1 to 3 or the blue pearlescent pigment prepared by the method of preparing the blue pearlescent pigment according to any one of claims 4 to 7.

10. An article comprising the blue pearl pigment according to any one of claims 1 to 3 or the blue pearl pigment produced by the method for producing the blue pearl pigment according to any one of claims 4 to 7;

preferably, the article is selected from plastic, leather or wallpaper.