Preparation method of erasable silicon dioxide physical color pigment without liquid assistance

Abstract

The invention discloses a liquid-assisted erasable silicon dioxide physical color pigment preparation method, which comprises: adding n-amyl alcohol into a conical flask, placing into a 30 DEG C water bath kettle, stirring, adding polyvinylpyrrolidone, anhydrous ethanol, ammonia water and deionized water when the temperature of the water bath kettle is increased to 50 DEG C so as to form a reversed-phase micro-emulsion system, stirring, and carrying out solid-liquid separation so as to obtain the liquid-assisted erasable silicon dioxide physical color pigment. Adding tetraethyl silicate into the system after the reaction is finished, shaking, putting into a drying oven, and standing for 24 hours; after standing, adding vinyltriethoxysilane into the system, oscillating and shaking, continuously putting into the oven at the temperature of 30 DEG C, and standing for 24 hours; the preparation method is simple, reaction conditions are mild, the prepared silicon dioxide physical color pigment can achieve erasable physical color generation on a black base material without liquid assistance, the anti-ultraviolet performance can be achieved when the silicon dioxide physical color pigment is smeared on a polyester fabric, and the anti-ultraviolet performance is good. The ultraviolet photoluminescence natural pigment is combined with the physical color pigment, so that information encryption and password transmission can be realized.

Description

Technical Field

[0001] The invention relates to the field of physical color materials, and in particular to a method for preparing a liquid-free erasable silicon dioxide physical color pigment. Background Art

[0002] In recent years, the field of colorants has faced the dual challenges of environmental protection and performance. Although functional pigments such as chemical colors are brightly colored and have strong covering power, their disadvantage is that they may contain chemical components that are harmful to the human body. Long-term use or improper handling may have adverse effects on health. At the same time, some chemical pigments are prone to cracking and discoloration after drying, which affects the long-term preservation of paintings, and some pigments are relatively expensive. For example, some organic colorants have poor stability, which affects the long-term preservation of artworks. Organic dyes are widely used, but are limited by problems such as mobility and low melting points. Although inorganic pigments have high thermal stability, they often contain heavy metals or transition metals, which raises environmental concerns. The large-scale use of synthetic colorants has led to serious environmental problems. Although natural colorants have a long history, they lack thermal stability and chemical durability. Therefore, it is necessary to develop more environmentally friendly, stable and high-performance colorants. Since chemical pigments and dyes can cause environmental pollution and easy fading of colors, physical colors have attracted widespread attention due to their high brightness, non-fading and pollution-free characteristics, and their applications in pigments, cosmetics, textiles, displays and colorimetric sensors are being explored to replace traditional chemical pigments and dyes to achieve more environmentally friendly and longer-lasting color performance. Physical color pigments have shown great potential in the art painting market due to their healthy and environmentally friendly characteristics, but most of their preparation methods are relatively complex and require liquid assistance, which limits their widespread application in the field of painting. Therefore, exploring the preparation technology of new functional physical color pigments that are simpler and do not require liquid assistance is of great significance to promoting the development of this material. Summary of the invention

[0003] The purpose of the present invention is to provide a method for preparing erasable silica physical color pigments without liquid assistance. The problems of complex preparation process of existing physical color pigments, reliance on liquid assistance, and high preparation cost are solved. The present invention is first based on the reverse microemulsion induction method. By simply adjusting the condition parameters under a mild static environment, silica photonic crystals with different particle sizes can be prepared. Erasable physical color generation and physical color printing can be achieved on black cardboard or polyester fabric by direct painting, and polyester fabric can be given excellent anti-ultraviolet properties. In addition, the color appearance of the physical pigments coated on black cardboard will completely disappear under ultraviolet irradiation. Inspired by this, ultraviolet photoluminescent natural pigments can be used as colorants and physical color pigments to participate in artistic pattern design. The synergistic effect of fluorescent plant pigments and physical color pigments realizes the information encryption and password transmission of graffiti graphic design. Compared with most physical color materials, the technical strategy of the present invention is simple, the operation is simple and gentle, and it is original in the direct painting of powdered physical color pigments. It is innovative and forward-looking in terms of the simple construction of new physical color materials and the construction of physical color multi-functional materials.

[0004] In order to achieve the above-mentioned invention object, the present invention adopts the following technical scheme:

[0005] A method for preparing a liquid-free erasable silica physical color pigment, the method comprising the following steps:

[0006] S1. After adding a certain amount of oily organic solvent into the conical flask, put the conical flask into a 30°C water bath, stir the solution in the conical flask, and adjust the water bath to 50°C;

[0007] S2. When the water bath temperature rises to 50°C, add an appropriate amount of polymer emulsifier to the conical flask and stir for 2 hours;

[0008] S3. After the stirring in step S2 is completed, the water bath is adjusted to 30°C, anhydrous ethanol, ammonia water and deionized water are added to the system in the conical flask, and stirred for 40 minutes;

[0009] S4. After the stirring in step S3 is completed, 3.5 mL of tetraethyl orthosilicate (TEOS) is added to the system in the conical flask, shaken for 2-3 minutes, and then placed in a 30°C oven for 24 hours;

[0010] S5. After step S4 is left standing, add 2 mL of silane coupling agent to the system in the conical flask, shake for 2-3 minutes, and then continue to place in a 30°C oven and stand for 24 hours;

[0011] S6, centrifugally washing the solution obtained in step S5, and drying after washing to obtain a silica physical color pigment;

[0012] Preferably, the oily organic solvent in step S1 above is n-pentanol, and the amount used is 50 mL.

[0013] Preferably, the polymer emulsifier in step S2 above is polyvinyl pyrrolidone (pvp), and the amount used is 5g.

[0014] Preferably, in step S3 described above, the volume ratio of anhydrous ethanol, aqueous ammonia and deionized water is 10:2 to 3.75:2.

[0015] Preferably, the silane coupling agent in step S5 described above is vinyl triethoxy silane (VTES).

[0016] Preferably, in step S6 described above, the solution obtained in step S5 is centrifuged and cleaned at room temperature using a centrifuge at a speed of 10,000 rpm for 10 min. After cleaning, the solution is dried in an oven at 70° C. for 2 h to obtain a silica physical color pigment.

[0017] Preferably, the amount of ammonia water in step S3 described above is 2-3.75 mL; the amount of silane coupling agent in step S5 is 0 mL-4 mL; by adjusting the amount of ammonia water and silane coupling agent, different colors of silica physical color pigments are obtained.

[0018] Furthermore, eight different colors of silica physical color pigments are obtained by adjusting the dosage of ammonia water and silane coupling agent.

[0019] Further, the oily organic solvent in step S1 is n-pentanol, and its dosage is 50 mL; the polymer emulsifier in step S2 is polyvinyl pyrrolidone (pvp), and the dosage is 5 g; the anhydrous ethanol in step S3 is 10 mL, and the deionized water is 2 mL; the silane coupling agent in step S5 is vinyl triethoxy silane (VTES);

[0020] The amount of ammonia water used in step S3 is 3 mL, and the amount of vinyl triethoxysilane (VTES) used in step S5 is 0.25 mL, and a pigment with a physical color of purple is obtained;

[0021] The amount of ammonia water used in step S3 is 3 mL, and the amount of vinyl triethoxysilane (VTES) used in step S5 is 0.75 mL, and a pigment with a physical color of bluish purple is obtained;

[0022] The amount of ammonia water used in step S3 is 3 mL, and the amount of vinyl triethoxysilane (VTES) used in step S5 is 1.25 mL, and a pigment with a physical color of rose pink is obtained;

[0023] The amount of ammonia water used in step S3 is 3 mL, and the amount of vinyl triethoxysilane (VTES) used in step S5 is 4 mL, and a pigment with a physical color of pink is obtained;

[0024] In step S3, the amount of ammonia water used is 2 mL, and no vinyl triethoxysilane (VTES) is added, and a pigment with a physical color of cyan is obtained;

[0025] In step S3, the amount of ammonia water used is 2.75 mL, and no vinyl triethoxysilane (VTES) is added, and a pigment having a physical color of green is obtained;

[0026] In step S3, the amount of ammonia water used is 3 mL, and no vinyl triethoxysilane (VTES) is added, and a pigment with a physical color of blue is obtained;

[0027] In step S3, the amount of ammonia water used is 3.75 mL, and no vinyltriethoxysilane (VTES) is added, and a pigment with an orange physical color is obtained.

[0028] Compared with the prior art, the present invention has the following beneficial effects:

[0029] (1) The present invention is based on reverse microemulsion induction and constructs silica photonic crystals under a mild static environment. This process shows the characteristics of high efficiency, short process and green cleaning. Its powder can realize erasable direct painting structure color on cardboard or polyester fabric, and give polyester excellent anti-ultraviolet performance. It can be seen that the above preparation process is simple and easy to implement, and the process parameters are mild. Therefore, it embodies the product advantages of green environmental protection and scalable production in the application scenarios of physical color pigments; it has a strong practical application advantage in constructing colorful physical color functional fabrics.

[0030] (2) The research, development and promotion of silica physical color pigment products not only helps to fill the gap in the current painting art market's demand for green, healthy and multifunctional pigments, but also profoundly reflects the cutting-edge trend of the integration of science and technology and traditional art, and further conforms to the trend of the times for science and technology to empower art and promote artistic innovation and upgrading. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 This is a forming diagram of a physical color pigment prepared by a reverse microemulsion method in an embodiment of the present invention;

[0032] Figure 2 The process of painting physical color pigment on black cardboard and the coloring schematic diagram in the embodiment of the present invention;

[0033] Figure 3 In the embodiment of the present invention, the erasable colored painting, from the chick pattern to the cloud pattern;

[0034] Figure 4This is a schematic diagram of a physical color pigment painted on black cardboard in an embodiment of the present invention;

[0035] Figure 5 This is a K / S curve diagram of eight physical color pigments applied on black cardboard in an embodiment of the present invention;

[0036] Figure 6 This is a schematic diagram of painting physical color pigments on fabric in an embodiment of the present invention;

[0037] Figure 7 This is a K / S curve diagram of eight physical color pigments applied on fabric in an embodiment of the present invention;

[0038] Figure 8 This is a graph showing the anti-ultraviolet performance test results of eight physical color pigments on fabrics in an embodiment of the present invention;

[0039] Fig. 9 This is a graph showing the changing effects of physical color pigments and ultraviolet photoluminescent natural pigments under daylight and ultraviolet light in an embodiment of the present invention. DETAILED DESCRIPTION

[0040] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the specific embodiments of the present invention are described in detail below in conjunction with the accompanying drawings. In the following description, many specific details are set forth to facilitate a full understanding of the present invention. However, the present invention can be implemented in many other ways different from those described herein, and those skilled in the art can make similar improvements without violating the connotation of the present invention, so the present invention is not limited by the specific embodiments disclosed below.

[0041] Example 1

[0042] The present invention provides a simple preparation method of a low-cost multifunctional erasable silica physical color pigment, which comprises the following steps:

[0043] S1. Use a measuring cylinder to measure 50 mL of n-pentanol and pour it into a conical flask, place it in a 30°C water bath, stir the solution in the conical flask, and adjust the water bath to 50°C;

[0044] S2. When the water bath temperature rises to 50°C, add 5 g of polyvinyl pyrrolidone (PVP) and stir for 2 h to obtain a mixed solution;

[0045] S3. After 2 h, adjust the water bath to 30 °C, add 10 mL of anhydrous ethanol, 3 mL of ammonia water, and 2 mL of deionized water to the mixed solution and stir for 40 min;

[0046] S4, add 3.5 mL of tetraethyl silicate to the system in step S3, shake for 2-3 minutes, and then place in a 30°C oven for 24 hours;

[0047] S5. After standing, add 0.25 mL of vinyl triethoxysilane (VTES) to the above system, shake for 2-3 minutes, and continue to stand in a 30°C oven for 24 hours;

[0048] S6. The solution obtained in step S5 is centrifuged and cleaned at room temperature using a centrifuge at a speed of 10,000 rpm for 10 min, and dried in an oven at 70° C. for 2 h to obtain a pigment with a physical color of purple.

[0049] Example 2

[0050] S1. Use a measuring cylinder to measure 50 mL of n-pentanol and pour it into a conical flask, place it in a 30°C water bath, stir the solution in the conical flask, and adjust the water bath to 50°C;

[0051] S2. When the water bath temperature rises to 50°C, add 5 g of polyvinyl pyrrolidone (PVP) and stir for 2 h to obtain a mixed solution;

[0052] S3. After 2 h, adjust the water bath to 30 °C, add 10 mL of anhydrous ethanol, 3 mL of ammonia water, and 2 mL of deionized water to the mixed solution and stir for 40 min;

[0053] S4, add 3.5 mL of tetraethyl silicate to the system in step S3, shake for 2-3 minutes, and then place in a 30°C oven for 24 hours;

[0054] S5. After standing, add 0.75 mL of vinyl triethoxysilane (VTES) to the above system, shake for 2-3 minutes, and continue to stand in a 30°C oven for 24 hours;

[0055] S6. The solution obtained in step S5 is centrifuged and cleaned at room temperature using a centrifuge at a speed of 10,000 rpm for 10 min, and dried in an oven at 70° C. for 2 h to obtain a blue-purple pigment.

[0056] Example 3

[0057] S1. Use a measuring cylinder to measure 50 mL of n-pentanol and pour it into a conical flask, place it in a 30°C water bath, stir the solution in the conical flask, and adjust the water bath to 50°C;

[0058] S2. When the water bath temperature rises to 50°C, add 5 g of polyvinyl pyrrolidone (PVP) and stir for 2 h to obtain a mixed solution;

[0059] S3. After 2 h, adjust the water bath to 30 °C, add 10 mL of anhydrous ethanol, 3 mL of ammonia water, and 2 mL of deionized water to the mixed solution and stir for 40 min;

[0060] S4, add 3.5 mL of tetraethyl silicate to the system in step S3, shake for 2-3 minutes, and then place in a 30°C oven for 24 hours;

[0061] S5. After standing, add 1.25 mL of vinyl triethoxysilane (VTES) to the above system, shake for 2-3 minutes, and continue to stand in a 30°C oven for 24 hours;

[0062] S6. The solution obtained in step S5 is centrifuged and cleaned at room temperature using a centrifuge at a speed of 10000 rpm for 10 min, and dried in an oven at 70° C. for 2 h to obtain a pigment with a physical color of rose pink.

[0063] Example 4

[0064] S1. Use a measuring cylinder to measure 50 mL of n-pentanol and pour it into a conical flask, place it in a 30°C water bath, stir the solution in the conical flask, and adjust the water bath to 50°C;

[0065] S2. When the water bath temperature rises to 50°C, add 5 g of polyvinyl pyrrolidone (PVP) and stir for 2 h to obtain a mixed solution;

[0066] S3. After 2 h, adjust the water bath to 30 °C, add 10 mL of anhydrous ethanol, 3 mL of ammonia water, and 2 mL of deionized water to the mixed solution and stir for 40 min;

[0067] S4, add 3.5 mL of tetraethyl silicate to the system in step S3, shake for 2-3 minutes, and then place in a 30°C oven for 24 hours;

[0068] S5. After standing, add 4 mL of vinyl triethoxysilane (VTES) to the above system, shake for 2-3 minutes, and continue to stand in a 30°C oven for 24 hours;

[0069] S6. The solution obtained in step S5 is centrifuged and cleaned at room temperature using a centrifuge at a speed of 10,000 rpm for 10 min, and dried in an oven at 70° C. for 2 h to obtain a pigment with a physical color of pink.

[0070] Example 5

[0071] S1. Use a measuring cylinder to measure 50 mL of n-pentanol and pour it into a conical flask, place it in a 30°C water bath, stir the solution in the conical flask, and adjust the water bath to 50°C;

[0072] S2. When the water bath temperature rises to 50°C, add 5 g of polyvinyl pyrrolidone (PVP) and stir for 2 h to obtain a mixed solution;

[0073] S3. After 2 h, adjust the water bath to 30 °C, add 10 mL of anhydrous ethanol, 2 mL of ammonia water, and 2 mL of deionized water to the mixed solution and stir for 40 min;

[0074] S4, add 3.5 mL of tetraethyl silicate to the system in step S3, shake for 2-3 minutes, and then place in a 30°C oven for 24 hours;

[0075] S5. The solution obtained in step S5 is centrifuged and cleaned at room temperature using a centrifuge at a speed of 10,000 rpm for 10 min, and dried in an oven at 70° C. for 2 h to obtain a pigment with a physical color of cyan.

[0076] Example 6

[0077] S1. Use a measuring cylinder to measure 50 mL of n-pentanol and pour it into a conical flask, place it in a 30°C water bath, stir the solution in the conical flask, and adjust the water bath to 50°C;

[0078] S2. When the water bath temperature rises to 50°C, add 5 g of polyvinyl pyrrolidone (PVP) and stir for 2 h to obtain a mixed solution;

[0079] S3. After 2 h, adjust the water bath to 30 °C, add 10 mL of anhydrous ethanol, 2.75 mL of ammonia water, and 2 mL of deionized water to the mixed solution and stir for 40 min;

[0080] S4, add 3.5 mL of tetraethyl silicate to the system in step S3, shake for 2-3 minutes, and then place in a 30°C oven for 24 hours;

[0081] S5. The solution obtained in step S5 is centrifuged and cleaned at room temperature using a centrifuge at a speed of 10000 rpm for 10 min, and then dried in an oven at 70° C. for 2 h to obtain a pigment having a physical color of green.

[0082] Example 7

[0083] S1. Use a measuring cylinder to measure 50 mL of n-pentanol and pour it into a conical flask, place it in a 30°C water bath, stir the solution in the conical flask, and adjust the water bath to 50°C;

[0084] S2. When the water bath temperature rises to 50°C, add 5 g of polyvinyl pyrrolidone (PVP) and stir for 2 h to obtain a mixed solution;

[0085] S3. After 2 h, adjust the water bath to 30 °C, add 10 mL of anhydrous ethanol, 3 mL of ammonia water, and 2 mL of deionized water to the mixed solution and stir for 40 min;

[0086] S4, add 3.5 mL of tetraethyl silicate to the system in step S3, shake for 2-3 minutes, and then place in a 30°C oven for 24 hours;

[0087] S5. The solution obtained in step S5 is centrifuged and cleaned at room temperature using a centrifuge at a speed of 10000 rpm for 10 min, and then dried in an oven at 70° C. for 2 h to obtain a blue pigment.

[0088] Example 8

[0089] S1. Use a measuring cylinder to measure 50 mL of n-pentanol and pour it into a conical flask, place it in a 30°C water bath, stir the solution in the conical flask, and adjust the water bath to 50°C;

[0090] S2. When the water bath temperature rises to 50°C, add 5 g of polyvinyl pyrrolidone (PVP) and stir for 2 h to obtain a mixed solution;

[0091] S3. After 2 h, adjust the water bath to 30 °C, add 10 mL of anhydrous ethanol, 3.75 mL of ammonia water, and 2 mL of deionized water to the mixed solution and stir for 40 min;

[0092] S4, add 3.5 mL of tetraethyl silicate to the system in step S3, shake for 2-3 minutes, and then place in a 30°C oven for 24 hours;

[0093] S5. The solution obtained in step S5 is centrifuged and cleaned at room temperature using a centrifuge at a speed of 10000 rpm for 10 min, and dried in an oven at 70° C. for 2 h to obtain a pigment with an orange physical color.

[0094] Table 1 is a summary table of the mass of materials added in Examples 1 to 8;

[0095]

[0096] It should be noted that the steps and operations of Examples 1 to 8 are basically the same, and only some reagent ratios are different. The preparation process of the product of Example 1 is used as an example for description below.

[0097] 1. Preparation of physical color pigments, see Figure 1 ;

[0098] An inverse microemulsion system, i.e., an oil-in-water emulsion, is formed by n-pentanol, PVP, and deionized water. Ammonia water is added thereto as a catalyst, and tetraethyl silicate is introduced. At this time, a sol-gel reaction occurs, and the emulsion changes from a transparent state to a milky white state. Then, the physical color pigment is obtained by standing at room temperature and centrifugal washing. Figure 1The first to seventh figures correspond to the state after steps S1-S5 are completed, and the eighth figure corresponds to step S6.

[0099] 2. Direct painting of physical color pigments on black cardboard, see Figure 2 ;

[0100] When a proper amount of the prepared physical color pigment is placed on black cardboard, it can be seen that its inherent color is white. However, after painting with a brush, brightly colored stripes appear, indicating that structural color can be achieved through this simple direct painting method. Figure 2 The three physical colors are blue, green and pink.

[0101] 3. Apply physical color pigments on black cardboard for erasable color application, see Table 2. Figures 3 to 5 ;

[0102] like Figure 3 As shown, the prepared physical color pigments of different colors were used to draw a blue chicken pattern on black card paper. Part of the drawn pattern was easily erased with an eraser, and then the unfinished colored area was redrawn to form a new colorful cloud pattern, which shows that the physical color pigment can be rewritable on the surface of black card paper without the help of a liquid medium; Figure 4 As shown in Table 2, physical color pigments were directly painted on black cardboard to draw multi-color graphics of the centenary celebration of Xinjiang University, showing gorgeous patterns and artistic colors. The chromaticity parameters and K / S curves of the cardboard surfaces coated with purple physical color pigments, blue-purple physical color pigments, rose pink physical color pigments, pink physical color pigments, cyan physical color pigments, green physical color pigments, blue physical color pigments, and orange physical color pigments were measured, as shown in Table 2 and Figure 5 As shown in the results, it can be seen that the coating on the cardboard shows good color performance. Therefore, the physical color pigment prepared in this project can be used as an environmentally friendly pigment in the field of color development and shows excellent application prospects and research value.

[0103] Table 2 shows the chromaticity parameters of eight physical color pigments applied on black cardboard

[0104]

[0105] 4. Apply physical color pigments to fabrics in an erasable color-generating manner, see Table 3. Figures 6-7 ;

[0106] like Figure 6 As shown in the figure, by directly painting the physical color pigment, the fabric surface is successfully painted. It can be used as a healthy and environmentally friendly powdered physical colorant for painting on a black substrate. It has good commercial possibilities and significant application potential in the fields of children's painting and graffiti art. The chromaticity parameters and K / S curves of the above eight physical color surfaces were measured, such as Figure 7 As shown in the results, it can be seen that the coating on the flexible substrate also shows good color performance. Therefore, the physical color pigment prepared in this project can be used to color fabrics and is expected to become a new type of textile colorant.

[0107] Table 3 shows the chromaticity parameters of eight physical color pigments applied on polyester fabrics

[0108]

[0109] 5. Test results of the UV resistance of physical color pigments on fabrics, see Table 4 and Figure 8 ;

[0110] In order to evaluate the anti-ultraviolet ability of fabrics coated with physical color pigments, the UPF values ​​and transmittances of the original white polyester fabric, the modified black polyester fabric, and eight kinds of polyester fabrics coated with physical color pigments were measured respectively. Table 4 shows the specific anti-ultraviolet test data. Sample No. 1 represents the original white fabric, No. 2 represents the modified black polyester fabric, No. 3 is the fabric coated with purple physical color pigment, No. 4 is the fabric coated with blue-purple physical color pigment, No. 5 is the fabric coated with rose pink physical color pigment, No. 6 is the fabric coated with pink physical color pigment, No. 7 is the fabric coated with cyan physical color pigment, No. 8 is the fabric coated with green physical color pigment, No. 9 is the fabric coated with blue physical color pigment, and No. 10 is the fabric coated with orange physical color pigment.

[0111] Table 4 shows the test results of UV resistance

[0112]

[0113] 6. Information encryption application of physical color pigments, see Fig. 9 ;

[0114] The color characteristics of the physical color pigment image prepared by the present invention on black cardboard will disappear under ultraviolet light. Based on this, we use ultraviolet photoluminescent natural pigments as colorants to collaborate with physical color pigments for artistic creation, such as Fig. 9 As shown, under daylight conditions, the surface of the black cardboard presents colorful artistic patterns of phoenix and Lop Noodles; under ultraviolet light, it presents Morse code and encrypted information respectively, realizing the information encryption and password transmission of graffiti graphic design.

[0115] Fig. 9In (a), under daylight conditions, the ultraviolet photoluminescent natural pigments and physical color pigments together present a colorful artistic pattern of a phoenix; under ultraviolet light, the physical color does not appear, and the natural pigment presents a Morse code pattern. Fig. 9 In (b), under daylight conditions, natural pigments and physical color pigments together present a colorful artistic pattern of Luobu hemp flowers; under ultraviolet light, the physical color does not show color, and the natural pigment presents an encrypted information graphic.

[0116] In addition, it should be understood that the above-described embodiments are only used to explain the present invention in detail, but the present invention is not limited to the above-mentioned detailed methods. For those skilled in the art, within the spirit and principle of the present invention, any improvement of the present invention, equivalent replacement of each raw material of the product of the present invention, selection of specific methods, etc., should all be included in the protection scope and disclosure scope of the present invention.

Claims

1. A method for preparing a liquid-free erasable silica physical color pigment, characterized in that: The following steps are involved: S1. After adding the oily organic solvent into the conical flask, place the conical flask in a 30 ℃ water bath, stir the solution in the conical flask, and adjust the water bath to 50 ℃; S2. When the water bath temperature rises to 50°C, add the polymer emulsifier to the conical flask and stir for 2 h; S3. After the stirring in step S2 is completed, the water bath is adjusted to 30°C, anhydrous ethanol, ammonia water and deionized water are added to the system in the conical flask, and stirred for 40 minutes; S4. After the stirring in step S3 is completed, 3.5 mL of tetraethyl silicate is added to the system in the conical flask, shaken for 2-3 minutes, and then placed in a 30°C oven for 24 hours; S5. After the step S4 is left to stand, add 2 mL of silane coupling agent to the system in the conical flask, shake for 2-3 minutes, and then place in a 30 °C oven and stand for 24 hours; S6. The solution obtained in step S5 is centrifuged and washed, and then dried to obtain a silica physical color pigment.

2. The method for preparing a liquid-free erasable silica physical color pigment according to claim 1, characterized in that: The oily organic solvent in step S1 is n-pentanol, and the amount used is 50 mL.

3. The method for preparing a liquid-free erasable silica physical color pigment according to claim 1, characterized in that: In step S2, the polymer emulsifier is polyvinyl pyrrolidone, and the amount used is 5 g.

4. The method for preparing a liquid-free erasable silica physical color pigment according to claim 1, characterized in that: In step S3, the volume ratio of anhydrous ethanol, aqueous ammonia and deionized water is 10:2 to 3.75:

2.

5. The method for preparing liquid-free erasable silica physical color pigment according to claim 1, characterized in that: The silane coupling agent in step S5 is vinyltriethoxysilane.

6. The method for preparing liquid-free erasable silica physical color pigment according to claim 1, characterized in that: In step S6, the solution obtained in step S5 is centrifuged and cleaned at room temperature using a centrifuge at a speed of 10,000 rpm for 10 min. After cleaning, the solution is dried in an oven at 70° C. for 2 h to obtain a silica physical color pigment.

7. The method for preparing a liquid-free erasable silica physical color pigment according to any one of claims 1 to 6, characterized in that: The amount of ammonia water used in step S3 is 2-3.75 mL; the amount of silane coupling agent used in step S5 is 0-4 mL; by adjusting the amount of ammonia water and silane coupling agent, silica physical color pigments of different colors are obtained.

8. The method for preparing liquid-free erasable silica physical color pigment according to claim 7, characterized in that: By adjusting the dosage of ammonia water and silane coupling agent, eight different colors of silica physical color pigments are obtained.

9. The method for preparing liquid-free erasable silica physical color pigment according to claim 8, characterized in that: The oily organic solvent in step S1 is n-pentanol, and its dosage is 50 mL; the polymer emulsifier in step S2 is polyvinyl pyrrolidone, and its dosage is 5 g; the anhydrous ethanol in step S3 is 10 mL, and the deionized water is 2 mL; the silane coupling agent in step S5 is vinyl triethoxy silane; In step S3, the amount of ammonia water used is 3 mL, and the amount of vinyltriethoxysilane used is 0.25 mL, and a pigment with a physical color of purple is obtained; In step S3, the amount of ammonia water used is 3 mL, and the amount of vinyltriethoxysilane used is 0.75 mL, and a pigment with a physical color of blue-purple is obtained; In step S3, the amount of ammonia water used is 3 mL, and the amount of vinyltriethoxysilane used is 1.25 mL, and a pigment with a physical color of rose pink is obtained; In step S3, the amount of ammonia water used is 3 mL, and the amount of vinyltriethoxysilane used is 4 mL, and a pigment with a physical color of pink is obtained; In step S3, the amount of ammonia water used is 2 mL, and no vinyltriethoxysilane is added, and a pigment with a physical color of cyan is obtained; In step S3, the amount of ammonia water used is 2.75 mL, and no vinyltriethoxysilane is added, and a pigment with a physical color of green is obtained; In step S3, the amount of ammonia water used is 3 mL, and no vinyltriethoxysilane is added, and a pigment with a physical color of blue is obtained; In step S3, the amount of ammonia water used is 3.75 mL, and no vinyltriethoxysilane is added, and a pigment with an orange physical color is obtained.

Images