Environment-friendly washable solid pigment and preparation method thereof

Abstract

The invention relates to an environment-friendly washable solid pigment and a preparation method thereof, the pigment comprises the following raw materials by weight: 40-60 parts of PEG, 2-4 parts of a stabilizer, 2-4 parts of a washable film-forming agent, 15-25 parts of a filler, 0.5-1.5 parts of toner and 4.5-13.5 parts of water, the average molecular weight of PEG is 6000-8000, the stabilizer comprises potassium lauryl phosphate and sodium dodecyl benzene sulfonate, the washable film-forming agent comprises sodium dodecyl benzene sulfonate, and the filler comprises sodium dodecyl benzene sulfonate. The washable film-forming agent comprises carrageenan, India gum and carboxymethyl starch in a mass ratio of 1: 1: (0.5-1.2), and the filler comprises aluminum oxide, magnesium oxide, heavy calcium carbonate and kaolin. The pigment disclosed by the invention is good in water solubility, easy to render after being dipped in water to draw, bright in color, stable in performance, good in water solubility and easy to clean on skin and fabrics.

Description

Technical Field

[0001] The invention relates to the technical field of watercolor pigments, and in particular to an environmentally friendly water-washable solid pigment and a preparation method thereof. Background Art

[0002] Watercolor pigments are delicate and transparent, and can produce a transparent and bright effect by reflecting the gloss of the white watercolor paper covered by the color. Watercolor painting uses water as a medium, and water has fluidity, which can produce special effects, which is different from the artistic expression of other types of paintings. The fluidity of water in the painting process, the changes in the wetness and dryness of the water-melted color, and the penetration effect on the paper make watercolor painting very expressive.

[0003] Although watercolor paints are easier to clean than traditional paints, not all washable paints can be easily washed off. Some paints may contain staining components that are difficult to remove, and even with soap or detergent, they may not be completely removed. Some washable paints have a high staining strength, and once they are stained on clothing or furniture, they may leave difficult-to-eliminate marks. At the same time, the components of some solid watercolor paint compositions may not be easily soluble in water or have poor mobility, resulting in the pigment components not being fully dissolved and moved to the side of the pen when rubbed with a pen containing water. Summary of the invention

[0004] The purpose of the present invention is to overcome the shortcomings of the prior art and provide an environmentally friendly water-washable solid pigment and a preparation method thereof which has the advantages of easy cleaning, bright colors, safety, environmental protection and convenient storage.

[0005] To achieve the above object, the technical solution adopted by the present invention is:

[0006] In a first aspect, the present invention provides an environmentally friendly water-washable solid pigment, comprising the following raw materials in parts by weight:

[0007] 40-60 parts of PEG, 2-4 parts of stabilizer, 2-4 parts of washable film-forming agent, 15-25 parts of filler, 0.5-1.5 parts of color powder and 4.5-13.5 parts of water, wherein the average molecular weight of the PEG is 6000-8000, the stabilizer comprises potassium lauryl phosphate and sodium dodecylbenzene sulfonate, the washable film-forming agent comprises carrageenan, ghatti gum and carboxymethyl starch in a mass ratio of 1:1:(0.5-1.2), and the filler comprises aluminum oxide, magnesium oxide, heavy calcium and kaolin.

[0008] The solid pigment of the present invention is based on PEG, and the average molecular weight of PEG is 6000-8000, so the viscosity of the pigment is relatively large. In order to avoid the aggregation and sedimentation of powder materials such as fillers and toners, potassium lauryl phosphate and sodium dodecylbenzene sulfonate are added, which can reduce the interfacial tension between the pigment particles, make the pigment particles more evenly mixed, and thus improve the stability of the pigment. At the same time, potassium lauryl phosphate has good compatibility with the skin, mild and low irritation, which also enables it to provide a milder and more effective cleaning effect when the pigment is attached to the skin and needs to be cleaned.

[0009] Since the solid pigment of the present invention has a high PEG content and an average molecular weight, the solid pigment is in a semi-dry jelly state, and PEG is a non-ionic surfactant that can reduce the surface tension of water and increase the wettability of the pigment, so that the solid pigment can be fully dissolved when dipped in water, making it easier to move the brush strokes when painting.

[0010] The washable film-forming agent of the present invention means that a film layer can be formed after the pigment dries, but the film layer can be easily washed off with water, and even if the pigment is accidentally thrown onto the skin, it can be easily washed off. Specifically, the washable film-forming agent is composed of carrageenan, carboxymethyl starch and ghatti gum. Carrageenan is a water-soluble polysaccharide that can form a gel-like structure and is helpful for the dispersion and dissolution of pigments in water. Carboxymethyl starch is a water-soluble modified starch, and its carboxymethyl group increases the hydrophilicity of the molecule and can improve the water solubility of the pigment. Gum ghatti is also a water-soluble natural colloid with good emulsification and dispersibility and can enhance the dissolution of the pigment in water. In the present invention, carrageenan can form a tough and transparent film with good film-forming performance and can be used as a film-forming agent for watercolor pigments. Carboxymethyl starch can increase the strength and flexibility of the film and improve the film-forming property of the pigment. Gum ghatti contains protein components and can enhance the stability and ductility of the film and is helpful for forming a uniform and dense film. Carrageenan, carboxymethyl starch and ghatti gum are added in a specific dosage ratio to produce a synergistic effect, thereby improving the dispersion and film-forming property of the pigment. At the same time, since the three are all water-soluble components, when the pigment is stained on the skin or furniture, the pigment can be removed by washing with water.

[0011] The filler of the present invention is a composition comprising aluminum oxide, magnesium oxide, heavy calcium and kaolin. When the nano-aluminum oxide and magnesium oxide are mixed with PEG, they fill the gaps between PEG molecules, thereby reducing the free volume between PEG molecules. This physical filling effect limits the movement space of the PEG molecular chain, making it more difficult for the PEG molecular chain to move or rearrange on a large scale when subjected to external force or temperature changes. At the same time, because aluminum oxide and magnesium oxide limit the interaction between PEG molecules, the crystallization tendency of PEG is reduced. Therefore, in addition to the filler function, aluminum oxide and magnesium oxide can also synergistically support PEG so that it is not easy to crystallize, while heavy calcium and kaolin can make the pigment more full and colorful.

[0012] Preferably, the weight portion of PEG in the pigment is 50-55 parts.

[0013] Preferably, the filler comprises the following components in parts by weight: 5-8 parts of aluminum oxide, 5-6 parts of magnesium oxide, 2-6 parts of heavy calcium oxide, and 3-5 parts of kaolin.

[0014] Preferably, the color powder includes at least one of titanium white, carbon black, phthalocyanine blue, phthalocyanine green, fast yellow, fast red, iron red, iron yellow, orange yellow, benzidine yellow, ruby, silver beads, ultramarine, permanent violet, permanent pink, rose color source, and permanent orange.

[0015] Preferably, the pigment further comprises 0.2-0.3 parts of preservative.

[0016] Preferably, the preservative is 2-methyl-4-isothiazolin-3-one and / or 2-methyl-5-chloro-4-isothiazolin-3-one.

[0017] Preferably, the stabilizer is a composition of potassium lauryl phosphate and sodium dodecylbenzene sulfonate in a mass ratio of 1:(0.5-1.5).

[0018] Preferably, the washable film-forming agent is a composition of carrageenan, gum ghatti and carboxymethyl starch in a mass ratio of 1:1:(1-1.2).

[0019] In a second aspect, the present invention provides a method for preparing an environmentally friendly water-washable solid pigment, comprising the following steps:

[0020] S1. Mix PEG and part of water, heat and stir at 80-90°C until PEG is completely dissolved, cool to 50-60°C, add aluminum oxide, magnesium oxide and a washable film-forming agent, stir evenly, and obtain a base slurry; aluminum oxide and magnesium oxide, as nanomaterials, will fill the gaps between PEG molecules, thereby reducing the free volume between PEG molecules. This physical filling effect will limit the movement space of PEG molecular chains, making it more difficult for PEG molecular chains to move or rearrange on a large scale when subjected to external force or temperature changes, thereby reducing the crystallization tendency of PEG.

[0021] S2. After mixing the stabilizer and the remaining water, add the color powder, heavy calcium and kaolin, and stir to obtain a color paste; wherein the stabilizer can reduce the interfacial tension between the pigment particles, making the pigment particles more evenly mixed, thereby improving the stability of the pigment.

[0022] S3, mixing the base slurry and the color slurry, stirring evenly, and curing the mixed slurry at 8-12° C. to obtain the environmentally friendly water-washable solid pigment.

[0023] Preferably, in step S1, the stirring speed is 200-400 r / min, and the stirring time is 10-30 min.

[0024] Preferably, in step S2, the stirring speed is 80-150 r / min, and the stirring time is 10-30 min.

[0025] Preferably, in step S3, the stirring speed is 80-150 r / min, the stirring time is 10-30 min, and the curing time is 10-20 min.

[0026] Compared with the prior art, the present invention has the following beneficial effects:

[0027] The environmentally friendly washable solid pigment of the present invention is based on PEG, which can reduce the surface tension of water and increase the wettability of the pigment, so that the solid pigment can be fully dissolved when dipped in water for use, which is convenient for moving the brushstrokes when drawing. Carrageenan, carboxymethyl starch and ghatti gum are added in a specific dosage ratio to produce a synergistic effect, thereby improving the dispersibility and film-forming property of the pigment. At the same time, because the three are all water-soluble components, when the pigment is stained on the skin or fabric, the pigment film can be removed by washing with water. Therefore, the pigment in the present invention has good water solubility, is easy to render after dipping in water for drawing, has bright colors, stable performance, and is easy to be cleaned on the skin and fabric. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 It is a physical picture of the solid pigment of the present invention. DETAILED DESCRIPTION

[0029] In order to better illustrate the purpose, technical solutions and advantages of the present invention, the present invention will be further described below in conjunction with specific embodiments.

[0030] The sources of the reagents used in the following examples and comparative examples are as follows:

[0031] PEG: PEG4000, PEG6000, and PEG8000 were all purchased from Liaoning Xindun Pharmaceutical Chemical Co., Ltd.; Potassium lauryl phosphate: the manufacturer was Jiangsu Hai'an Petrochemical Plant, brand MA24PK-50;

[0032] Sodium dodecylbenzene sulfonate: manufacturer is Shanghai Aladdin Biochemical Technology Co., Ltd., brand number is S108366;

[0033] Carrageenan: The manufacturer is Shanghai Yuanye Biotechnology Co., Ltd., the brand is S30559, the purity is BR, and the strength is 1200;

[0034] Gum India: The manufacturer is Shanghai Aladdin Biochemical Technology Co., Ltd., brand number is G 120958;

[0035] Carboxymethyl starch: the manufacturer is Shanghai Aladdin Biochemical Technology Co., Ltd., brand number C804711;

[0036] Alumina: The manufacturer is Hangzhou Hengna New Materials Co., Ltd., brand name is ZH-Alum80, average particle size is 20nm;

[0037] Magnesium oxide: The manufacturer is Zhejiang Yamei Nano Technology Co., Ltd., the brand is LT-MgO-001, and the particle size is 30-50nm.

[0038] Unless otherwise specified, other materials, reagents, etc. used in the examples and comparative examples can be obtained from commercial sources.

[0039] Example 1

[0040] An environmentally friendly washable solid pigment, characterized in that it is made of the following raw materials in parts by weight:

[0041] 55 parts of PEG, 3 parts of stabilizer, 3 parts of washable film-forming agent, 20.9 parts of filler, 1 part of color powder, 0.25 parts of preservative and 10 parts of water, wherein the average molecular weight of the PEG is 6000, the stabilizer is a composition of potassium lauryl phosphate and sodium dodecylbenzene sulfonate in a mass ratio of 1:1.2, the washable film-forming agent is a composition of carrageenan, ghatti gum and carboxymethyl starch in a mass ratio of 1:1:1, the filler includes the following components in parts by weight: 7 parts of aluminum oxide, 5.2 parts of magnesium oxide, 4 parts of heavy calcium, 4.7 parts of kaolin, the color powder is iron red, and the preservative is 2-methyl-4-isothiazoline-3-one.

[0042] The method for preparing an environmentally friendly water-washable solid pigment comprises the following steps:

[0043] S1. Mix PEG and 2 / 3 of water, heat at 85°C and stir at 300 r / min for 25 min until PEG is completely dissolved, cool to 55°C, add aluminum oxide, magnesium oxide and a washable film-forming agent, and stir at 300 r / min for 15 min to obtain a base slurry;

[0044] S2. After mixing the stabilizer and the remaining water, add the color powder, heavy calcium and kaolin, and stir at a speed of 100 r / min for 20 min to obtain a color paste;

[0045] S3, mixing the base slurry and the color slurry, stirring at a speed of 100 r / min for 20 minutes, and then curing the mixed slurry at 10° C. for 15 minutes to obtain the environmentally friendly water-washable solid pigment. Figure 1 As shown, the pigment of the present invention is in a semi-dry jelly state.

[0046] Example 2

[0047] An environmentally friendly washable solid pigment, characterized in that it is made of the following raw materials in parts by weight:

[0048] 40 parts of PEG, 2 parts of stabilizer, 2 parts of washable film-forming agent, 15 parts of filler, 0.5 parts of color powder, 0.2 parts of preservative and 4.5 parts of water, wherein the average molecular weight of the PEG is 4000, the stabilizer is a composition of potassium lauryl phosphate and sodium dodecylbenzene sulfonate in a mass ratio of 1:0.5, the washable film-forming agent is a composition of carrageenan, ghatti gum and carboxymethyl starch in a mass ratio of 1:1:0.5, the filler comprises the following components in parts by weight: 5 parts of aluminum oxide, 5 parts of magnesium oxide, 2 parts of heavy calcium, 3 parts of kaolin, the color powder is orange, and the preservative is 2-methyl-5-chloro-4-isothiazoline-3-one.

[0049] The method for preparing an environmentally friendly water-washable solid pigment comprises the following steps:

[0050] S1. Mix PEG and half of water, heat at 80°C and stir at 200 r / min for 30 min until PEG is completely dissolved, cool to 50°C, add aluminum oxide, magnesium oxide and washable film-forming agent, stir at 200 r / min for 20 min to obtain base slurry;

[0051] S2. After mixing the stabilizer and the remaining water, add the color powder, heavy calcium and kaolin, and stir at a speed of 80 r / min for 30 min to obtain a color paste;

[0052] S3, mixing the base slurry and the color slurry, and stirring at a speed of 80r / min for 30min, and then curing the mixed slurry at 8°C for 20min to obtain the environmentally friendly water-washable solid pigment.

[0053] Example 3

[0054] An environmentally friendly washable solid pigment, characterized in that it is made of the following raw materials in parts by weight:

[0055] 60 parts of PEG, 4 parts of stabilizer, 4 parts of washable film-forming agent, 25 parts of filler, 1.5 parts of color powder, 0.3 parts of preservative and 13.5 parts of water, wherein the average molecular weight of the PEG is 8000, the stabilizer is a composition of potassium lauryl phosphate and sodium dodecylbenzene sulfonate in a mass ratio of 1:1.5, the washable film-forming agent is a composition of carrageenan, ghatti gum and carboxymethyl starch in a mass ratio of 1:1:1.2, the filler comprises the following components in parts by weight: 8 parts of aluminum oxide, 6 parts of magnesium oxide, 6 parts of heavy calcium, 5 parts of kaolin, the color powder is phthalocyanine green, and the preservative is 2-methyl-4-isothiazoline-3-one.

[0056] The method for preparing an environmentally friendly water-washable solid pigment comprises the following steps:

[0057] S1. Mix PEG and 2 / 3 of water, heat at 90°C and stir at 400 r / min for 10 min until PEG is completely dissolved, cool to 60°C, add aluminum oxide, magnesium oxide and washable film-forming agent, stir at 400 r / min for 10 min to obtain base slurry;

[0058] S2. After mixing the stabilizer and the remaining water, add the color powder, heavy calcium and kaolin, and stir at a speed of 150 r / min for 10 min to obtain a color paste;

[0059] S3, mixing the base slurry and the color slurry, stirring at a speed of 150 r / min for 10 min, and then curing the mixed slurry at 12° C. for 10 min to obtain the environmentally friendly water-washable solid pigment.

[0060] Example 4

[0061] The difference between Example 4 and Example 1 is that the total amount of the washable film-forming agent remains unchanged, and the washable film-forming agent is a composition of carrageenan, gum ghatti and carboxymethyl starch in a mass ratio of 1:1:0.5.

[0062] Example 5

[0063] The difference between Example 5 and Example 1 is that the total amount of the washable film-forming agent remains unchanged, and the washable film-forming agent is a composition of carrageenan, gum ghatti and carboxymethyl starch in a mass ratio of 1:1:0.8.

[0064] Example 6

[0065] The difference between Example 6 and Example 1 is that the total amount of the washable film-forming agent remains unchanged, and the washable film-forming agent is a composition of carrageenan, gum ghatti and carboxymethyl starch in a mass ratio of 1:1:1.2.

[0066] Comparative Example 1

[0067] The difference between Comparative Example 1 and Example 1 is that no stabilizer is added and the stabilizer is supplemented with water.

[0068] Comparative Example 2

[0069] The difference between Comparative Example 2 and Example 1 is that the total amount of the stabilizer remains unchanged, and the stabilizer is only potassium lauryl phosphate.

[0070] Comparative Example 3

[0071] The difference between Comparative Example 3 and Example 1 is that the total amount of the stabilizer remains unchanged and the stabilizer is only sodium dodecylbenzene sulfonate.

[0072] Comparative Example 4

[0073] The difference between Comparative Example 4 and Example 1 is that the total amount of the washable film-forming agent remains unchanged, and the washable film-forming agent is a composition of carrageenan, ghatti gum and carboxymethyl starch in a mass ratio of 1:1:0.4.

[0074] Comparative Example 5

[0075] The difference between Comparative Example 5 and Example 1 is that the total amount of the washable film-forming agent remains unchanged, and the washable film-forming agent is carrageenan, gum ghatti and carboxymethyl starch in a mass ratio of 1:1:1.3.

[0076] Comparative Example 6

[0077] The difference between Comparative Example 6 and Example 1 is that the amount of filler added remains unchanged, aluminum oxide and magnesium oxide are not added, and heavy calcium oxide and kaolin are used to make up the amount in a mass ratio of 4:4.7.

[0078] Comparative Example 7

[0079] The difference between Comparative Example 7 and Example 1 is that the amount of filler added remains unchanged, no alumina is added, and heavy calcium oxide and kaolin are used to make up the amount in a mass ratio of 4:4.7.

[0080] Comparative Example 8

[0081] The difference between Comparative Example 8 and Example 1 is that the amount of filler added remains unchanged, magnesium oxide is not added, and heavy calcium and kaolin are used to make up the amount in a mass ratio of 4:4.7.

[0082] Comparative Example 9

[0083] Comparative Example 9 is different from Example 1 in that aluminum oxide and magnesium oxide are not added in step S1 of the method for preparing the pigment, but in step S2, aluminum oxide and magnesium oxide are mixed together with heavy calcium and kaolin.

[0084] Performance Testing

[0085] 1. Skin washability: The arms of 5 subjects were divided into test areas, and the same amount (0.5 g) of the pigments of Examples 1 to 6 and Comparative Examples 1 to 9 were dipped respectively to draw a 5 cm long straight line on the arm area. To ensure the same brushstrokes, the same type of silicone brush was used for smearing. After smearing, a hair dryer was used to blow at 60°C for 15 minutes until the pigment was completely dry. Then rinse with clean water for 2 minutes, observe the area to be tested, and score the pigments in each area according to Table 1. The higher the score, the better the washability. Take the average of the five scores, and record the score in Table 2.

[0086] 2. Washability of textiles: Mark the area to be tested on a pure white cotton T-shirt, apply 1g of each of the pigments of Examples 1 to 6 and Comparative Examples 1 to 9 to the area to be tested with a silicone brush, and place in an 80°C drying oven to dry for 30 minutes. Take out the T-shirt and soak it in clean water for 10 minutes. Take it out and dry the cotton T-shirt, observe the area to be tested, and score the pigments in each area according to Table 1. The higher the score, the better the washability. Take the average of the five scores and record the score in Table 2.

[0087] Table 1 Washability evaluation table

[0088]

[0089] 3. Pigment stability test: Put the pigments of Examples 1-6 and Comparative Examples 1-9 into two iron boxes, each containing no less than 15g of pigment, remove air bubbles, seal with cellophane and mark, and then cover the iron box. Put the iron box into a 75-80℃ automatic thermostat and a -15~-20℃ freezer for 72 hours, take it out and store it at room temperature. After the pigments have been stored at room temperature for more than 3 hours, the fluidity is measured and compared with the fluidity of the ink that has not been heated and frozen. See Table 2 for details.

[0090] 4. Safety test: The pigment of Example 1 was subjected to a cytotoxicity test, as follows:

[0091] Take a human immortalized epidermal cell line (HaCaT) with a stable growth state, adjust the cell concentration to 1×105 / mL, and inoculate 100 μL per well into a 96-well cell culture plate (except the outermost wells and blank control wells). Add 200 μL of PBS to the outermost wells of the cell culture plate to reduce the evaporation of the culture medium. Place in a carbon dioxide incubator and culture at 37°C±1°C, CO2 concentration 5.0%±1% until the cell fusion reaches more than 90%. Add samples, the sample concentration is 10 mg / L, set blank control and sample group, 100 μL per well. Start adding the sample (sample group) and PBS (blank control) of Example 1, keep the time interval between each two columns of sample additions consistent, ensure that the intervention time of each test substance on the cells is 5 minutes, after 5 minutes, suck off the test substances in turn, add PBS to each well to wash the test substances, and wash twice. When using a vacuum suction pump or a discharge gun to suck off the liquid in the well, operate carefully to avoid sucking off the surviving cells and affecting the experimental results. 100 μL of complete medium and 10 μL of CCK-8 solution were added to each well and cultured in an incubator for about 2 hours. The absorbance (OD) value was measured at a wavelength of 450 nm and the cell viability was calculated, as shown in formula (1). The results are shown in Table 3.

[0092]

[0093] Table 2 Washability and stability data of each group of pigments

[0094]

[0095] Table 3 Pigment cytotoxicity test of Example 1

[0096] Experimental Group HaCaT survival rate % Example 1 97.6 Blank control group 100

[0097] As can be seen from Table 2, Examples 1, 4-6 and Comparative Examples 4-5 are intended to explore the effect of the mass ratio of carrageenan, gum ghatti and carboxymethyl starch on the performance of the pigment. Among them, the washability of the pigments of Examples 1 and 4-6 is better than that of Comparative Examples 4-5, indicating that the washable film-forming agent includes a composition of carrageenan, gum ghatti and carboxymethyl starch in a mass ratio of 1:1:(0.5-1.2). Within this ratio range, the pigment can obtain better washability. If too much carboxymethyl starch is added (such as Comparative Example 5), the pigment will be too thick and difficult to apply evenly. Precipitation and stratification will also occur at high and low temperatures, thereby reducing the stability of the pigment. If too little carboxymethyl starch is added (such as Comparative Example 4), the consistency of the watercolor pigment is not enough to meet the painting requirements, resulting in the pigment being easy to flow and diffuse and difficult to control, so that the carboxymethyl starch may not be able to fully exert its thickening and stabilizing properties, resulting in limited performance improvement of carrageenan and gum ghatti. Figure 1 As shown, the pigment of the present invention is in a semi-dry jelly state.

[0098] Example 1 and Comparative Examples 1-3 are to explore the effects of potassium lauryl phosphate and sodium dodecylbenzene sulfonate in the stabilizer on the performance of the pigment. As can be seen from the data in Table 2, potassium lauryl phosphate and sodium dodecylbenzene sulfonate have a synergistic effect, which can better improve the stability of the pigment and also improve the washability of the pigment in skin and fabric.

[0099] Example 1 and Comparative Examples 6-8 are to explore the effects of aluminum oxide and magnesium oxide on the performance of the pigment. As can be seen from the data in Table 2, aluminum oxide, magnesium oxide, heavy calcium and kaolin have a synergistic effect, which can better improve the stability of the pigment and improve the washability of the pigment in skin and fabric. This may be because aluminum oxide and aluminum oxide will fill the gaps between PEG molecules when mixed with PEG, thereby reducing the free volume between PEG molecules. This physical filling effect will limit the movement space of the PEG molecular chain, thereby reducing the crystallization tendency of PEG.

[0100] Example 1 and Comparative Example 9 are to explore the effect of the order of adding aluminum oxide and magnesium oxide on the performance of the pigment. It can be seen from the data in Table 2 that when preparing the pigment, aluminum oxide and magnesium oxide must be mixed with PEG first, and then mixed with other raw materials to obtain a pigment with good stability and washability.

[0101] It can be seen from Table 3 that the cell survival rate of Example 1 is 97.6%, which shows that the pigment of Example 1 has little effect on cell viability, that is, it has good safety.

[0102] In summary, the pigment of the present invention has good water solubility, is easy to render after being dipped in water for painting, has bright colors, stable performance, and has good water solubility, and is easy to wash off the skin and fabrics.

[0103] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the present invention rather than to limit the scope of protection of the present invention. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solution of the present invention can be modified or replaced by equivalents without departing from the essence and scope of the technical solution of the present invention.

Claims

1. An environmentally friendly washable solid pigment, characterized in that: The invention comprises the following raw materials in parts by weight: 40-60 parts of PEG, 2-4 parts of stabilizer, 2-4 parts of washable film-forming agent, 15-25 parts of filler, 0.5-1.5 parts of color powder and 4.5-13.5 parts of water, wherein the average molecular weight of the PEG is 6000-8000, the stabilizer comprises potassium lauryl phosphate and sodium dodecylbenzene sulfonate, the washable film-forming agent comprises carrageenan, ghatti gum and carboxymethyl starch in a mass ratio of 1:1:(0.5-1.2), and the filler comprises aluminum oxide, magnesium oxide, heavy calcium and kaolin.

2. The environmentally friendly water-washable solid pigment according to claim 1, characterized in that: The filler comprises the following components in parts by weight: 5-8 parts of aluminum oxide, 5-6 parts of magnesium oxide, 2-6 parts of heavy calcium oxide, and 3-5 parts of kaolin.

3. The environmentally friendly water-washable solid pigment according to claim 1, characterized in that: The color powder includes at least one of titanium white, carbon black, phthalocyanine blue, phthalocyanine green, fast yellow, fast red, iron red, iron yellow, orange yellow, benzidine yellow, ruby, silver beads, ultramarine, permanent purple, permanent pink, rose color source, and permanent orange.

4. The environmentally friendly water-washable solid pigment according to claim 1, characterized in that: The pigment also includes 0.2-0.3 parts of preservatives.

5. The environmentally friendly water-washable solid pigment according to claim 4, characterized in that: The preservative is 2-methyl-4-isothiazoline-3-one and / or 2-methyl-5-chloro-4-isothiazoline-3-one.

6. The environmentally friendly water-washable solid pigment as claimed in claim 1 or 4, characterized in that: The mass ratio of the potassium lauryl phosphate to sodium dodecylbenzene sulfonate is 1:(0.5-1.5).

7. The environmentally friendly water-washable solid pigment as claimed in claim 1 or 4, characterized in that: The washable film-forming agent is a composition of carrageenan, ghatti gum and carboxymethyl starch in a mass ratio of 1:1:(1-1.2).

8. A method for preparing an environmentally friendly water-washable solid pigment according to any one of claims 1 to 7, characterized in that: The following steps are involved: S1. Mix PEG and part of water, heat and stir at 80-90°C until PEG is completely dissolved, cool to 50-60°C, add aluminum oxide, magnesium oxide and a washable film-forming agent, stir evenly, and obtain a base slurry; S2, after mixing the stabilizer and the remaining water, add the color powder, heavy calcium and kaolin, and stir to obtain a color paste; S3, mixing the base slurry and the color slurry, stirring evenly, and curing the mixed slurry at 8-12°C to obtain the environmentally friendly water-washable solid pigment.

9. The method for preparing the environmentally friendly water-washable solid pigment according to claim 8, characterized in that: In step S1, the stirring speed is 200-400 r / min, and the stirring time is 10-30 min.

10. The method for preparing the environmentally friendly water-washable solid pigment according to claim 8, characterized in that: In step S2, the stirring speed is 80-150 r / min, and the stirring time is 10-30 min.

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