CN112391066B

CN112391066B - Preparation of near-infrared reflection phosphate color pigment

Info

Publication number: CN112391066B
Application number: CN202011424907.2A
Authority: CN
Inventors: 张艳辉; 尚龙安; 许冠杰
Original assignee: Zhejiang University of Science and Technology ZUST
Current assignee: Zhejiang University of Science and Technology ZUST
Priority date: 2020-11-17
Filing date: 2020-12-08
Publication date: 2021-11-19
Anticipated expiration: 2040-12-08
Also published as: CN112391066A

Abstract

A near-infrared reflection pigment and a preparation method thereof are characterized in that: the colored high near-infrared reflection porous heat-insulating pigment is prepared by adopting a microwave-gel method-combustion method combined process. The general chemical formula of the pigment provided by the invention is M_xAl_1‑xPO₄(M is non-ferrous metal ion, x is 0-0.2). The invention uses AlPO₄The pigment is a matrix, is doped with nonferrous metal ions, ensures the high heat-insulating property of the pigment, and enriches the color of the pigment.

Description

Preparation of near-infrared reflection phosphate color pigment

Technical Field

The invention belongs to the technical field, relates to a preparation method of an inorganic pigment, and particularly relates to aluminum phosphate (AlPO)₄) A method for preparing ion-doped and composite high Near Infrared Reflection (NIR) pigment used as a matrix.

Background

Phosphate has excellent performances such as corrosion resistance, flame retardance and the like, is nontoxic and has low use cost, so that in recent years, phosphate pigments are widely applied to the fields of building materials, chemical engineering, refractory materials and the like. In fact, the advantages of the phosphate in the near infrared reflection aspect are also obvious, the near infrared reflectivity of the white phosphate is 95%, the phosphate material is prepared by a domestic common coprecipitation method, wherein Sudagen and the like prepare white NaZnPO by the coprecipitation method₄The reflectivity of the product of the porous material in the near infrared band under the optimal process is up to 95.2 percent, which is 87 percent higher than that of the common rutile TiO powder (rutile type TiO)₂) And also high, which makes phosphate have great potential in the field of thermal insulation. Phosphate is a white pigment, and although it is excellent in various properties, it is difficult to satisfy aesthetic requirements for color. Thus, white phosphate is taken as a matrix, different chromophoric metal ions are added to change the color of the material, so as to balance the near infrared reflection of the marketThe ratio and the color. Shing Yong et al doped transition metal Fe by chemical coprecipitation method to obtain a series of doped aluminum phosphate pigments, the reflectivity of near infrared part is reduced from 97.77% to 72.56%, and compared with similar commercially available pigments, the doped aluminum phosphate pigments have high heat reflection performance. Xia et al NaZnPO by doping Cu₄The pigment of (2) is modified, although the reflectivity of the product is reduced, the pigment obtains color, and the reflectivity of the product in a near infrared band is 51% under an optimal process. The white phosphate has been found to have a high reflectance, e.g. NaZnPO₄And KZnPO₄Has been demonstrated, but there has been little research on colorization of aluminum phosphate pigments. The aluminum phosphate pigment takes the aluminum phosphate in phosphate as a matrix, and a series of aluminum phosphate pigments with different colors and high infrared reflectivity are obtained by doping metal ions.

Disclosure of Invention

The invention aims to provide a microwave-gel method-combustion method combined process, which takes an aluminum phosphate pigment as a matrix to prepare a colored NIR reflecting energy-saving pigment. The preparation method comprises the following steps:

(1) taking nitrate, phosphoric acid and citric acid as raw materials, weighing according to a designed molecular formula, and adding deionized water to stir uniformly; (2) placing the system in a microwave oven for heating and stirring, and naturally cooling to obtain a gel precursor; (3) transferring the gel precursor into a crucible, putting the crucible into a muffle furnace for calcining, naturally cooling to room temperature after calcining is finished, and finally obtaining a product M_xAl_1-xPO₄(M＝Co、Ni，x＝0.0-0.2)。

It is further preferred that the first and second liquid crystal compositions,

step (1) with AlPO₄Doping metal element to replace Al element as matrix, quantitatively weighing aluminum nitrate raw material according to designed molar ratio, taking 0.02mol phosphoric acid (purity 85%) as reference, and obtaining molecular formula M_xAl_1-xPO₄The other nitrates were weighed and the citric acid was weighed in equimolar amounts of phosphoric acid and all dissolved in 20ml of deionized water.

The heating temperature in the step (2) is 75-90 ℃, and the stirring is carried out for 60-110 min.

The calcining temperature in the step (3) is 1000-1600 ℃, and the calcining time is 1-3 h.

The invention has the beneficial effects that: the porous aluminum phosphate-based pigment powder is prepared by adopting a microwave-gel method-combustion method combined process, the color saturation of the porous aluminum phosphate-based pigment powder is higher than that of a coprecipitation method, the heat distribution of a microwave heating method in the process is uniform and has no loss, and metal ions are well dispersed in a system. Co_xAl_1-xPO₄The near infrared reflectivity is reduced from 113.92% (by taking barium sulfate as a reference when testing) to 50.91% and Ni as the doping amount of cobalt ions is increased (x is 0.0-0.2)_xAl_1-xPO₄The near infrared reflectivity is reduced from 113.92% to 59.62% along with the increase of the doping amount of nickel ions (x is 0.0-0.2). Taking into account color and near-IR reflectance, Co_0.1Al_0.9PO₄And Ni_0.1Al_0.9PO₄The pigment is ideal purple and yellow pigments, the reflectivity is 73.51% and 74.96%, respectively, the temperature difference between the synthesized pigment with similar chroma and the commercial pigment (permanent violet YBVF2301P and cadmium yellow P1110) is 10.2 ℃ and 4.3 ℃, and the good heat insulation effect is the combined effect result of near infrared reflection and air barrier in material gaps. The aluminum phosphate doped series pigment can exert the original anti-corrosion and flame-retardant characteristics, has better heat-insulating property and rich colors and has wide market prospect compared with the commercial pigment.

Description of the drawings:

FIG. 1 shows AlPO prepared in examples 1, 2 and 3₄、Co_0.05Al_0.95PO₄、Co_0.1Al_0.9PO₄XRD pattern of the powder. As can be seen, the aluminum phosphate appears in the cristobalite form (PDF)^#72-1161) phase and tridymite type Phase (PDF)^#70-4689). After Co element doping, the aluminophosphate tridymite type phase disappears, and Co appears at a diffraction angle of 29-30 DEG₂P₂O₇Crystalline Phase (PDF)^#49-1091)。

FIG. 2 shows AlPO prepared in examples 1, 4 and 5₄、Ni_0.05Al_0.95PO₄、Ni_0.1Al_0.9PO₄XRD pattern of the powder. As can be seen from the figure, after the Ni element is doped,the tridymite type phase showed disappearance with the appearance of Ni₂P₂O₇Crystalline Phase (PDF)^#74-1604)。

FIG. 3 shows M prepared in examples 2 and 4_0.05Al_0.95PO₄SEM image of powder. As can be seen, the nanoparticles sinter into a porous material. Co in FIG. 3(A)_0.05Al_0.95PO₄Powder particle ratio of Ni in FIG. 3(B)_0.05Al_0.95PO₄The powder has large particles.

FIG. 4 shows AlPO prepared in examples 1, 2 and 3₄、Co_0.05Al_0.95PO₄、Co_0.1Al_0.9PO₄The near infrared reflectance of the powder. When tested, the white aluminum phosphate pigment has good near infrared reflection performance by taking barium sulfate as a reference. The calculated near infrared average reflectivity of the aluminum phosphate is 113.92%, Co_0.05Al_0.95PO₄Has a near infrared average reflectance of 86.01%, Co_0.1Al_0.9PO₄The near infrared average reflectance of (a) was 73.51%.

FIG. 5 shows AlPO prepared in examples 1, 4 and 5₄、Ni_0.05Al_0.95PO₄、Ni_0.1Al_0.9PO₄The near infrared reflectance of the powder. Calculated as Ni_0.05Al_0.95PO₄Has a near infrared average reflectance of 87.00% and Ni_0.1Al_0.9PO₄The near infrared average reflectance of (a) was 74.96%.

FIG. 6 shows M prepared in examples 1, 2, 3, 4 and 5_xAl_1-xPO₄(M ═ Co, Ni; x ═ 0.00, 0.05, 0.1) CIE parameters. a and b represent chroma, positive values for a represent red, negative values represent green, positive values for b represent yellow, and negative values represent blue; c represents chroma; l denotes the lightness of the pigment, L ═ 0 is black, L ═ 50 is gray, and L ═ 100 is white. As can be seen from the data of fig. 6, as the ratio of Co to Ni increases, the lightness L decreases and the chroma C increases. For a, b, as the proportion of Co increases, a becomes positive and larger, red increases, b becomes smaller and smaller, blue increasesAnd (4) color enhancement. Thus, the pigment is purple-toned and darker in color. As the Ni ratio increased, a was positive and increased slightly, red increased slightly, b was larger and larger, and yellow increased. The pigments are thus yellow in shade and increasingly darker in color. Consistent with the panels of fig. 4 and 5.

FIG. 7 shows M prepared in examples 2, 3, 4 and 5_xAl_1-xPO₄(M ═ Co, Ni;, x ═ 0.05, 0.1) was compared to the thermal insulation performance of commercially available pigments (permanent violet YBVF2301P and cadmium yellow P1110). The temperature was measured on the other side of the baffle, coated with different pigment coatings, by irradiation with an infrared lamp, as shown in figure 7. It can be seen that the thermal insulating properties of the pigments in the examples are superior to those of commercially available pigments. For the two classes of pigments in the examples of the present invention, the maximum temperature differences from commercially available pigments were 14.1 ℃ and 8.1 ℃ respectively, and the chroma differences from commercially available pigments were 10.2 ℃ and 4.3 ℃.

Detailed Description

The invention is further illustrated by the following examples, without restricting the scope of the invention thereto.

Example 1

1ml of phosphoric acid (85% purity) was weighed out, and 7.5g of aluminum nitrate nonahydrate and 3.84g of citric acid were weighed out and dissolved in 20ml of deionized water. The system is placed in an experimental microwave oven and stirred for 90min at the temperature of 80 ℃ to form a precursor. Transferring the precursor into a crucible, and calcining the precursor in a muffle furnace at 1000 ℃ for 2h to finally obtain a product AlPO₄。

Example 2

0.02mol of phosphoric acid (purity 85%) is measured according to the molecular formula Co_0.05Al_0.95PO₄Cobalt nitrate and aluminum nitrate were weighed and citric acid was weighed in equimolar amounts to phosphoric acid, all dissolved in 20ml of deionized water. The system is placed in an experimental microwave oven and stirred for 90min at the temperature of 80 ℃ to form a precursor. Transferring the precursor into a crucible, putting the crucible into a muffle furnace, and calcining the precursor for 2 hours at 1000 ℃ to finally obtain a product Co_0.05Al_0.95PO₄。

Example 3

Measuring 0.02mol phosphoric acid (purity 85%), rootAccording to the formula Co_0.2Al_0.8PO₄Cobalt nitrate and aluminum nitrate were weighed and citric acid was weighed in equimolar amounts to phosphoric acid, all dissolved in 20ml of deionized water. The system is placed in an experimental microwave oven and stirred for 90min at the temperature of 80 ℃ to form a precursor. Transferring the precursor into a crucible, putting the crucible into a muffle furnace, and calcining the precursor for 2 hours at 1000 ℃ to finally obtain a product Co_0.1Al_0.9PO₄。

Example 4

0.02mol of phosphoric acid (purity 85%) is measured according to the molecular formula Ni_0.05Al_0.95PO₄Cobalt nitrate and aluminum nitrate were weighed and citric acid was weighed in equimolar amounts to phosphoric acid, all dissolved in 20ml of deionized water. The system is placed in an experimental microwave oven and stirred for 90min at the temperature of 80 ℃ to form a precursor. Transferring the precursor into a crucible, and calcining the precursor in a muffle furnace at 1000 ℃ for 2h to finally obtain a product Ni_0.05Al_0.95PO₄。

Example 5

0.02mol of phosphoric acid (purity 85%) is measured according to the molecular formula Ni_0.1Al_0.9PO₄Cobalt nitrate and aluminum nitrate were weighed and citric acid was weighed in equimolar amounts to phosphoric acid, all dissolved in 20ml of deionized water. The system is placed in an experimental microwave oven and stirred for 90min at the temperature of 80 ℃ to form a precursor. Transferring the precursor into a crucible, and calcining the precursor in a muffle furnace at 1000 ℃ for 2h to finally obtain a product Ni_0.1Al_0.9PO₄。

Claims

1. The preparation method of the colored high near-infrared reflection inorganic pigment is characterized in that

The method comprises the following steps:

(1) taking nitrate, phosphoric acid and citric acid as raw materials, weighing according to a designed molecular formula, and adding deionized water to stir uniformly; with AlPO₄Doping metal element M to replace Al element as matrix, quantitatively weighing aluminum nitrate raw material according to designed molar ratio, taking 0.02mol phosphoric acid with purity of 85% as reference, and according to molecular formula M_xAl_1-xPO₄Weighing doped metal nitrate, weighing citric acid according to the equimolar amount of phosphoric acid, and completely dissolving the citric acid in 20ml of deionized water;

(2) placing the system in a microwave oven, heating and stirring, and naturally cooling to obtain a gel precursor; the heating temperature is 75-90 ℃, and the stirring is carried out for 60-110 min;

(3) transferring the gel precursor into a crucible, putting the crucible into a muffle furnace for calcining, naturally cooling to room temperature after calcining is finished, and finally obtaining a product M_xAl_1-xPO₄Wherein, M is Co and Ni, and x is 0.05-0.2; the calcination temperature is 1000-1600 ℃, and the calcination time is 1-3 h.