Preparation method of low-temperature lead-free ceramic pigment

Abstract

The invention discloses a preparation method of a low-temperature lead-free ceramic pigment. The preparation method specifically comprises the following steps: S1, preparing a cobalt blue solution: weighing CoSO4 and A12 (SO4) 3, adding purified water into a beaker, and dissolving; s2, preparing an emulsion: uniformly mixing and stirring petroleum ether, a surfactant and a cosurfactant for later use; s3, slowly adding the cobalt blue solution in the step S1 into the emulsion in the step S2 to obtain a premixed solution; s4, repeating the step S2, uniformly stirring, adding a precipitant, and uniformly stirring to obtain an emulsion II; s5, re-mixing: adding the emulsion II into the pre-mixed solution, uniformly stirring, and adjusting the pH value to neutral alkaline; stopping stirring, carrying out suction filtration, and drying to obtain a cobalt blue premix; s6, adding the cobalt blue premix into a ball mill for grinding; and S7, adding the cobalt blue premix into a muffle furnace for calcining, re-burning, water quenching and drying to obtain the low-temperature lead-free ceramic pigment. The average particle size of the prepared ceramic pigment is 38-55nm, and the ceramic pigment can be used as an ink-jet pigment.

Description

Technical Field

[0001] The invention belongs to the technical field of pigments, and in particular relates to a method for preparing a low-temperature lead-free ceramic pigment. Background Art

[0002] Ceramic pigments have a long history of development. As an important decorative material for ceramic surfaces, they are of great significance in beautifying ceramic products and improving the artistic value of ceramic products. In the process of ceramic manufacturing, these pigments must undergo calcination at different temperatures and are used for coloring the body and oil, drawing patterns, etc.

[0003] As a component of pigment flux, PbO has made outstanding contributions to the wide range of baking temperatures (760-860℃) and pure and bright color of overglaze ceramic pigments; CdO plays an important role in the decoration of ceramic appearance with its unique and gorgeous colors. Therefore, from ancient times to the present, PbO and CdO have been used in traditional ceramic pigment formulas. However, lead, cadmium and their compounds are harmful to human health. There is evidence that all lead compounds are potential carcinogens.

[0004] Cobalt compounds have been used as coloring materials in ceramic products for a long time. Cobalt blue pigments were first used in ceramics in the Tang Dynasty in my country, and Persians also began to use cobalt-based pigments for decoration in the 9th century. Cobalt blue has always been an important color inorganic pigment, which is widely used because of its good heat resistance, light resistance and chemical corrosion resistance. Summary of the invention

[0005] The purpose of the present invention is to provide a method for preparing a low-temperature lead-free ceramic pigment, which can obtain a pigment for inkjet by adopting an emulsion dispersion method.

[0006] The purpose of the present invention can be achieved through the following technical solutions:

[0007] A method for preparing a low-temperature lead-free ceramic pigment comprises the following steps:

[0008] S1. Prepare cobalt blue solution: weigh 1.55g CoSO4 and 3.42g Al2(SO4)3 in a beaker, the molar ratio of Co to Al is 1:2, and add purified water to dissolve;

[0009] S2. Prepare emulsion: Add 140-150g petroleum ether, 40-45g surfactant, 35-40g co-surfactant to a beaker, stir well and set aside;

[0010] S3 initial mixing: at 25-30 ℃, the cobalt blue solution of step S1 is slowly added to the emulsion of step S2, and stirring is maintained to obtain a premixed solution;

[0011] S4. Preparation of emulsion II: 14-15g petroleum ether, 4-4.5g surfactant, 3.5-4.0g co-surfactant were added to a beaker and stirred, 5.0-6.0g of aqueous dimethylamine precipitant was added thereto, and stirred to obtain emulsion II;

[0012] S5. Remixing: adding the emulsion prepared in step S4 to the premixed solution prepared in step S3 while stirring at 25-30°C, stirring evenly, adjusting the pH of the solution to a neutral alkaline state with a mass concentration of 5-7% sodium hydroxide aqueous solution; continuing stirring for 2-4h, and measuring the pH of the solution again to be in a neutral alkaline state; stopping stirring, filtering, and drying to obtain a cobalt blue premix;

[0013] S6. Add the cobalt blue premix to a ball mill for grinding until the particle size is less than 100 um and then grind out of the mill;

[0014] S7. Add the cobalt blue premix of step S6 into a muffle furnace for calcination for 2-3 hours, and obtain a low-temperature lead-free ceramic pigment after re-firing, water quenching and drying.

[0015] Furthermore, the neutral alkaline pH in step S5 is 9.0-9.5.

[0016] Furthermore, the calcination temperature in step S7 is 700-800°C.

[0017] Furthermore, the surfactant is rosin amine polyoxyethylene ether, and the structural formula is as follows:

[0018]

[0019] Among them, m=15-25; n=15-25.

[0020] Further, the co-surfactant is pentaerythritol or sorbitol;

[0021] Furthermore, the particle size of the ceramic pigment is 38-55 nm.

[0022] Beneficial effects of the present invention:

[0023] The present invention selects rosin amine polyoxyethylene ether as a surfactant, which has no positive or negative charge center, will not dissociate, has good compatibility with other components, can adapt to a wide pH range, has high stability and is not restricted by acid, alkali, and salt, and the ether bond in the molecule is not easily destroyed by acid or alkali. The co-surfactant can well reduce the surface tension, is conducive to the dispersion of the pigment, and forms particulate ions. The synergistic effect of the surfactant and the co-surfactant makes it difficult for the pigment particles to aggregate, and the particles are difficult to form large particles. The average particle size of the prepared ceramic pigment is 38-55nm, and due to its high fineness, it has good fluidity and lubricity, can achieve better dispersion, suspension and stability, and has good color performance, can be used for inkjet pigments, and the printed image is clearer.

[0024] Of course, any product implementing the present invention does not necessarily need to achieve all of the advantages described above at the same time. DETAILED DESCRIPTION

[0025] The technical solutions in the embodiments of the present invention are described clearly and completely. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0026] A method for preparing a low-temperature lead-free ceramic pigment comprises the following steps:

[0027] S1. Prepare cobalt blue solution: weigh 1.55g CoSO4 and 3.42g Al2(SO4)3 in a beaker, the molar ratio of Co to Al is 1:2, and add purified water to dissolve;

[0028] S2. Prepare emulsion: Add 145g petroleum ether, 45g surfactant, 35g co-surfactant to a beaker, stir well and set aside;

[0029] S3. Initial mixing: at 30°C, the cobalt blue solution of step S1 was slowly added to the emulsion of step S2, and stirring was maintained to obtain a premixed solution;

[0030] S4. Preparation of emulsion II: 14 g petroleum ether, 4 g surfactant, 3.5 g co-surfactant were added to a beaker and stirred, to which was added 5.0 g of an aqueous solution of dimethylamine precipitant and stirred to obtain emulsion II;

[0031] S5. Remixing: adding the emulsion prepared in step S4 to the premixed solution prepared in step S3 at 30°C while stirring, and adjusting the pH of the solution to a neutral alkaline pH of 9.0 using a 5% sodium hydroxide aqueous solution; continuing stirring for 2-4h, and measuring the pH of the solution again to be within the range of 9.0-9.5; stopping stirring, filtering, and drying to obtain a cobalt blue premix;

[0032] S6. Add the cobalt blue premix to a ball mill for grinding until the particle size is less than 100 um and then grind out of the mill;

[0033] S7. Add the cobalt blue premix of step S6 into a muffle furnace and calcine at 700°C for 2h, then obtain low-temperature lead-free ceramic pigment after re-sintering, water quenching and drying. A Nano-ZS Malvern particle size distribution analyzer, with PEG400 as the dispersant, after ultrasonic dispersion, measures that the particle size of the prepared pigment is 38-55nm.

[0034] The surfactant is rosin amine polyoxyethylene ether, and the structural formula is as follows:

[0035]

[0036] Among them, m=15-25; n=15-25.

[0037] The co-surfactant is pentaerythritol or sorbitol;

[0038] Rosin amine polyoxyethylene ether is selected as a surfactant. It has no positive or negative charge center, will not dissociate, has good compatibility with other components, can adapt to a wide pH range, has high stability and is not restricted by acid, alkali, and salt. The ether bond in the molecule is not easily destroyed by acid or alkali. The co-surfactant can effectively reduce the surface tension, which is beneficial to the dispersion of the pigment and the formation of microparticle ions. The synergistic effect of the surfactant and the co-surfactant makes it difficult for the pigment particles to aggregate and the particles to form large particles. The average particle size of the ceramic pigment is 38-55nm. Due to its high fineness, it has good fluidity and lubricity, can achieve better dispersion, suspension and stability, and has good color performance. It can be used for inkjet pigments, and the printed image is clearer.

[0039] The above contents are merely examples and explanations of the concept of the present invention. The technicians in this technical field may make various modifications or additions to the specific embodiments described or replace them in a similar manner. As long as they do not deviate from the concept of the invention or exceed the scope defined by the claims, they should all fall within the protection scope of the present invention.

Claims

1. A method for preparing a low-temperature lead-free ceramic pigment, characterized in that: The following steps are involved: S1. Prepare cobalt blue solution: weigh 1.55g CoSO4 and 3.42g Al2(SO4)3 in a beaker, with a molar ratio of Co to Al of 1:2, and add purified water to dissolve; S2. Prepare emulsion: Add 140-150g petroleum ether, 40-45g surfactant, 35-40g co-surfactant to a beaker, stir well and set aside; S3 initial mixing: at 25-30 ℃, the cobalt blue solution of step S1 is slowly added to the emulsion of step S2, and stirring is maintained to obtain a premixed solution; S4. Preparation of emulsion II: 14-15g petroleum ether, 4-4.5g surfactant, 3.5-4.0g co-surfactant were added to a beaker and stirred, 5.0-6.0g of aqueous dimethylamine precipitant was added thereto, and stirred to obtain emulsion II; S5. Remixing: adding the emulsion prepared in step S4 to the premixed solution prepared in step S3 while stirring at 25-30°C, stirring evenly, adjusting the pH of the solution to a neutral alkaline state with a mass concentration of 5-7% sodium hydroxide aqueous solution; continuing stirring for 2-4h, and measuring the pH of the solution again to be in a neutral alkaline state; stopping stirring, filtering, and drying to obtain a cobalt blue premix; S6. Add the cobalt blue premix to a ball mill for grinding until the particle size is less than 100 um and then grind out of the mill; S7. Add the cobalt blue premix of step S6 into a muffle furnace for calcination for 2-3 hours, and obtain a low-temperature lead-free ceramic pigment after re-firing, water quenching and drying.

2. The method for preparing a low-temperature lead-free ceramic pigment according to claim 1, characterized in that: The neutral alkaline pH in step S5 is 9.0-9.

5.

3. The method for preparing a low-temperature lead-free ceramic pigment according to claim 1, characterized in that: The calcination temperature in step S7 is 700-800°C.

4. The method for preparing a low-temperature lead-free ceramic pigment according to claim 1, characterized in that: The surfactant is rosin amine polyoxyethylene ether, and the structural formula is as follows: Among them, m=15-25; n=15-25.

5. The method for preparing a low-temperature lead-free ceramic pigment according to claim 1, characterized in that: The co-surfactant is pentaerythritol or sorbitol.

6. The method for preparing a low-temperature lead-free ceramic pigment according to claim 1, characterized in that: The particle size of the ceramic pigment is 38-55nm.

Images