Lead-free, lithium-free and re-firing-free overglaze silk screen pigment for ceramic and preparation method of overglaze silk screen pigment

Abstract

The invention discloses a lead-free lithium-free re-firing-free overglaze silk screen pigment for ceramics, which comprises a colorant and a flux in a weight ratio of (8-30%): (70-92%), the flux is prepared from the following raw material components in parts by weight: 35 to 75 parts of silicon dioxide (SiO2), 3 to 20 parts of diboron trioxide (B2O3), 1.5 to 10 parts of aluminum oxide (Al2O3), 1 to 12 parts of zirconium silicate (ZrSiO4), 1 to 8.5 parts of bismuth trioxide (Bi2O3), 1 to 10 parts of fluorine F and acidic oxide. The toner is a lead-free toner. The preparation method comprises the following steps: S1, preparing a flux; and S2, mixing a colorant with the prepared flux to obtain the powdery pigment. The color agent and the flux are mixed through a dry ball milling process to achieve the same effect as re-burning heat treatment in the prior art, so that in the pigment preparation process, the physical and chemical performance improvement process of high-temperature re-burning heat treatment is omitted, the quality and the production efficiency of a pigment product are improved, and the production cost is reduced.

Description

Technical Field

[0001] The invention belongs to the technical field of ceramic pigments, and in particular relates to a lead-free, lithium-free, and re-fire-free ceramic on-glaze screen pigment and a preparation method thereof. Background Art

[0002] The most widely used decoration method for ceramic products is overglaze color. Overglaze color is used at a low temperature of 750℃ to 850℃, so 30-50% lead oxide is added in the traditional production process to make the ceramic overglaze pigment have a wide firing temperature range and pure color. However, the pollution of the atmosphere and water resources and the harm to the human body caused by the production and use of lead in ceramic pigments have attracted worldwide attention, especially the lead dissolution on the surface of tableware and drinking utensils is a potential carcinogen, posing a threat to people's health. In order to reduce and eradicate the toxicity of lead, the scientific research and production departments of the ceramic decoration industry at home and abroad have been making unremitting efforts.

[0003] At present, the flux of the widely used on-glaze silk screen pigment for ceramics has poor physical and chemical properties. During the production process, a high-temperature re-firing heat treatment process must be performed to strengthen the physical and chemical properties of the on-glaze silk screen pigment products so that the products can meet the above requirements. At present, the production process of on-glaze silk screen pigment for ceramics widely used in China is as follows: fine grinding (using a ball mill, alcohol or water as a grinding medium, and pebbles as a grinding body) - drying - re-firing heat treatment - fine grinding - drying - crushing, packaging - finished product. Among them, the re-firing heat treatment process refers to the semi-finished pigment being calcined at a temperature of 780-800°C to a semi-molten state, and then quenched and crushed with water; the purpose is to improve the chemical stability of the finished pigment, enhance its corrosion resistance, reduce the amount of lead and cadmium dissolved, improve the glossiness, thermal stability and other physical and chemical properties, and also have the effect of deepening the color depth and improving the color tone. If the re-firing heat treatment process is not performed, the physical and chemical properties of the above-mentioned pigments are as follows: poor chemical stability, low glossiness, light color, and dull color. However, the addition of the re-firing heat treatment process also brings many problems. For example, the addition of the re-firing heat treatment process will inevitably require the addition of "secondary fine grinding, secondary drying" and other processes, which makes the production process complicated, occupies more plant equipment, consumes a large amount of alcohol or water, electricity, labor, auxiliary materials, etc. In addition, there are many semi-finished product turnover links and a long production cycle, resulting in high energy consumption, low efficiency, and difficult production management and quality control. Summary of the invention

[0004] The object of the present invention is to provide a lead-free, lithium-free and re-fire-free ceramic on-glaze screen pigment and a preparation method thereof, which can solve at least one of the above-mentioned problems.

[0005] According to one aspect of the present invention, a lead-free, lithium-free, and refire-free ceramic on-glaze screen pigment is provided, comprising a colorant and a flux, wherein the weight ratio of the colorant to the flux is 8-30%:70-92%;

[0006] The raw material composition of the flux includes the following components in parts by weight:

[0007] 35-75 parts of silicon dioxide SiO2, 3-20 parts of boron trioxide B2O3, 1.5-10 parts of aluminum oxide Al2O3, 1-12 parts of zirconium silicate ZrSiO4, 1-8.5 parts of bismuth trioxide Bi2O3, 1-10 parts of fluorine F and acidic oxides;

[0008] The colorant is lead-free.

[0009] In some embodiments, the flux further comprises the following components by weight:

[0010] Potassium oxide K2O≤10 parts, sodium oxide Na2O≤10 parts, magnesium oxide MgO≤5 parts, zinc oxide ZnO≤4 parts, calcium oxide CaO≤5.5 parts and barium oxide BaO≤4 parts.

[0011] In some embodiments, the acidic oxide is one or more of zirconium dioxide ZrO2, titanium dioxide TiO2 and tin oxide SnO2, zirconium dioxide ZrO2≤3 parts, titanium dioxide TiO2≤3 parts, tin oxide SnO2≤8.5 parts.

[0012] In some embodiments, the flux further includes lanthanum oxide La2O3≤1 part and strontium oxide SrO≤4 parts.

[0013] According to another aspect of the present invention, there is provided a method for preparing a lead-free, lithium-free, and refire-free ceramic on-glaze screen pigment, comprising the following steps:

[0014] S1. preparing flux;

[0015] S2. Mixing the colorant with the flux prepared above to obtain a powdered pigment.

[0016] In some embodiments, the preparation process of the flux in step S1 is:

[0017] S101, mixing the raw materials of various components of the flux that have passed through a 80-120 mesh sieve;

[0018] S102, melting the mixed components at a temperature of 1250-1350° C.;

[0019] S103, quenching the product obtained after the above melting with cold water, then grinding it by ball milling, and drying it to obtain flux for use.

[0020] In some embodiments, in step S2, the colorant is mixed with the flux and a finished powder is obtained by dry ball milling.

[0021] In some embodiments, the particle size of the particles obtained after ball milling in step S103 is less than 5 um.

[0022] The beneficial effects of the present invention are:

[0023] 1. By adding a small amount of bismuth trioxide and fluorine to the flux, the melting temperature can be effectively reduced; at the same time, the colorant and the flux are mixed through a dry ball milling process to achieve the same effect as the double-firing heat treatment in the prior art. Therefore, in the pigment preparation process, the high-temperature double-firing heat treatment process for physical and chemical properties is omitted, so as to improve the quality and production efficiency of pigment products and reduce production costs.

[0024] 2. The flux does not contain lead oxide and uses easily available and inexpensive silicon dioxide as the main component, which greatly reduces the material cost of the flux.

[0025] 3. Alumina and boron trioxide can form a uniform and dense grid structure, which is conducive to the preparation of ceramic pigments with pure color and good chemical stability. At the same time, by adding acidic oxides to the flux, the structure of the flux is made tighter. The composite flux composed of a large amount of alkali metals and alkaline earth metals reduces the increase in the expansion coefficient caused by the addition of alkali metals and alkaline earth metals.

[0026] 4. Neither the flux nor the colorant contains lead and lithium. Therefore, when the pigment is used in ceramics, it effectively avoids lead dissolution, avoids lead pollution to the atmosphere and water resources, improves people's safety when using it, and is beneficial to the health of users. DETAILED DESCRIPTION

[0027] The present invention is further described in detail below.

[0028] The lead-free, lithium-free and re-fire-free ceramic glaze screen pigment provided by the present invention comprises a colorant and a flux, wherein the weight ratio of the colorant to the flux is 8-30%:70-92%.

[0029] The raw material composition of the flux includes the following components in parts by weight:

[0030] 35-75 parts of silicon dioxide SiO2, 3-20 parts of boron trioxide B2O3, 1.5-10 parts of aluminum oxide Al2O3, 1-12 parts of zirconium silicate ZrSiO4, 1-8.5 parts of bismuth trioxide Bi2O3, 1-10 parts of fluorine F and acidic oxides;

[0031] The colorant is lead-free.

[0032] The weight ratio of the colorant to the flux can be adjusted according to the actual color when the colorant and the flux are actually mixed. Specifically, when the weight ratio of the colorant is 8%, the flux accounts for 92%; when the weight ratio of the colorant is 30%, the flux accounts for 70%; when the weight ratio of the colorant is 19%, the flux accounts for 81%.

[0033] The flux also includes the following components by weight:

[0034] Potassium oxide K2O≤10 parts, sodium oxide Na2O≤10 parts, magnesium oxide MgO≤5 parts, zinc oxide ZnO≤4 parts, calcium oxide CaO≤5.5 parts and barium oxide BaO≤4 parts.

[0035] The acidic oxide is one or more of zirconium dioxide ZrO2, titanium dioxide TiO2 and tin oxide SnO2, with zirconium dioxide ZrO2≤3 parts, titanium dioxide TiO2≤3 parts, and tin oxide SnO2≤8.5 parts.

[0036] The flux also includes lanthanum oxide La2O3≤1 part and strontium oxide SrO≤4 parts.

[0037] In the actual production process, silicon dioxide SiO2 is used as the main component of the flux, and expensive lithium oxide is not required, which greatly reduces the material cost. By adding boron trioxide B2O3 and aluminum oxide Al2O3, a uniform and dense grid structure can be formed during the preparation of the pigment, so that the pigment has pure color and stable chemical properties; at the same time, the composite flux composed of a large amount of alkali metals and alkaline earth metals greatly improves the acid resistance of the pigment by means of the mixed alkali effect while reducing the melting temperature of the flux. By adding acidic oxides, not only the structure of the flux is made tighter, but also the increase in the expansion coefficient caused by the addition of alkali metals and alkaline earth metals is reduced. The components in the flux of the present invention have undergone a large number of scientific and rigorous formula experiments, which not only makes its various physical and chemical performance indicators meet international standards, but also avoids the drawbacks of high baking temperature and high price of similar products at home and abroad.

[0038] In specific production, the composition of the flux can be adjusted according to the actual required pigment color, and the color of the added colorant can be selected according to the actual situation, and the details are as follows:

[0039] Example 1

[0040] When a colorant such as dark green, blue green, light green, fruit green, sea blue, dark black, silver gray, and white is selected, the weight ratio of the components of the flux is: 45-60 parts of silicon dioxide SiO2, 8-20 parts of boron trioxide B2O3, 3-7 parts of aluminum oxide Al2O3, 1-12 parts of zirconium silicate ZrSiO4, 3-8.5 parts of bismuth trioxide Bi2O3, 1-8 parts of fluorine F, 1-10 parts of sodium oxide Na2O, 1-10 parts of potassium oxide K2O, 0.1-1.1 parts of barium oxide BaO, 1-12 parts of zirconium silicate ZrSiO4, 0.1-4 parts of tin oxide SnO2, 0.1-1 parts of lanthanum oxide La2O3, 0.1-3 parts of magnesium oxide MgO, 0.1-3 parts of calcium oxide CaO, and 0.1-2 parts of zinc oxide ZnO.

[0041] Example 2

[0042] When purple, deep red, pink and other colorants are selected, the weight ratio of the components of the flux is: 36-50 parts of silicon dioxide SiO2, 8-12 parts of boron trioxide B2O3, 3-8 parts of aluminum oxide Al2O3, 2-9 parts of zirconium silicate ZrSiO4, 3-6 parts of bismuth trioxide Bi2O3, 1-3 parts of fluorine F, 1-8 parts of sodium oxide Na2O, 1-8 parts of potassium oxide K2O, 3-8.5 parts of tin oxide SnO2, 0.1-3 parts of zinc oxide ZnO and 0.5-3 parts of titanium dioxide TiO2.

[0043] Example 3

[0044] When using dark selenium red, light selenium red, orange yellow or cadmium yellow as colorants, the weight ratio of each component of the flux is:

[0045] 35-60 parts of silicon dioxide SiO2, 8-12 parts of boron trioxide B2O3, 4-10 parts of aluminum oxide Al2O3, 2-10 parts of zirconium silicate ZrSiO4, 1-3.5 parts of bismuth trioxide Bi2O3, 4-6 parts of fluorine F, 1-3 parts of potassium oxide K2O, 1-3 parts of barium oxide BaO, 0.1-4 parts of strontium oxide SrO, 1-3 parts of tin oxide SnO2, 0.1-1 parts of lanthanum oxide La2O3, 0.5-3 parts of calcium oxide CaO, 0.1-3 parts of zinc oxide ZnO and 1-3 parts of zirconium dioxide ZrO2.

[0046] Example 4

[0047] When a colorant such as non-golden pink is selected, the weight ratio of each component of the flux is:

[0048] 35-50 parts of silicon dioxide SiO2, 8-13 parts of boron trioxide B2O3, 1.5-7 parts of aluminum oxide Al2O3, 2-4 parts of zirconium silicate ZrSiO4, 2-3.5 parts of bismuth trioxide Bi2O3, 5-10 parts of fluorine F, 0.5-2 parts of sodium oxide Na2O, 0.1-1.5 parts of strontium oxide SrO, 3-4.1 parts of tin oxide SnO2, 0.1-0.5 parts of lanthanum oxide La2O3 and 2-5.5 parts of calcium oxide CaO.

[0049] Example 5

[0050] When cobalt blue is used as a colorant, the weight ratio of each component of the flux is:

[0051] 65-75 parts of silicon dioxide SiO2, 3-10 parts of boron trioxide B2O3, 3-5 parts of aluminum oxide Al2O3, 1.5-10 parts of zirconium silicate ZrSiO4, 2-3.5 parts of bismuth trioxide Bi2O3, 1-2 parts of fluorine F, 2-5 parts of sodium oxide Na2O, 0.5-3 parts of potassium oxide K2O, 0.1-4 parts of barium oxide BaO, 0.5-2 parts of tin oxide SnO2, 0.1-5 parts of magnesium oxide MgO and 1-4 parts of zinc oxide ZnO.

[0052] In the above embodiments, by adding a small amount of bismuth and fluorine into the flux, the melting temperature is reduced, thereby achieving energy saving effect.

[0053] The present invention also provides a method for preparing the above-mentioned lead-free, lithium-free and re-fire-free ceramic on-glaze screen pigment, comprising the following steps:

[0054] S1. preparing flux; specifically, according to different color requirements, preparing corresponding components of the flux according to the above ratios.

[0055] S2. Evenly mix the colorant and the flux prepared above to obtain a powdered pigment.

[0056] The preparation process of the flux in step S1 is as follows:

[0057] S101, uniformly mix the corresponding component raw materials of the flux through a 80-120 mesh sieve;

[0058] S102, melting the mixed components at a temperature of 1250-1350° C.;

[0059] S103, quenching the product obtained after melting with cold water, then ball milling, drying and preparing flux for use, wherein the particle size of the particles obtained after ball milling is less than 5 μm.

[0060] The flux particles obtained above are subjected to the operation of step S2, in which the colorant is mixed with the flux and a finished powder is obtained by dry ball milling.

[0061] When the colorant and flux are mixed, the finished powder is directly obtained by dry ball milling, which eliminates the high-temperature re-firing heat treatment process for physical and chemical properties, thereby improving the quality and production efficiency of pigment products and greatly reducing production costs.

[0062] The ceramic on-glaze screen pigment prepared by the present invention is lead-free ceramic pigment, lead-free dissolution, non-toxic and side effects, compact structure, good chemical stability, low baking temperature, complete and perfect color system, acid and alkali corrosion resistance, thermal expansion coefficient matching, pure color, bright color, high gloss, and good decorative effect.

[0063] The ceramic on-glaze screen pigment prepared by the preparation method of the present invention is used in the same manner as the pigment obtained by high-temperature re-firing in the prior art, with a use temperature of 700-800° C. and a heat preservation time of 8-20 minutes.

[0064] After screen printing, direct printing or spraying on the surface of ceramic products, and keeping at 700-800℃ for 8-20 minutes, the physical and chemical properties are measured as follows:

[0065] Glossiness: 80-90%, using WGG60-2 gloss meter to measure the glossiness of the flower surface after baking;

[0066] Thermal expansion coefficient: 6.0~7.0×10-6 / ℃;

[0067] Chemical stability: lead dissolution is 0.00mg / dm 2 The cadmium dissolution of some pigments containing cadmium colorants is 0.1-0.26 mg / dm 2 After being immersed in 4% acetic acid solution at 22±2℃ for 24 hours, or in 0.5% Na2CO3 solution at 60±2℃ for 40 hours, the hue and color did not change.

[0068] The above-mentioned corresponding flux and the corresponding colorant are mixed, and the pigment prepared by the preparation method of the present invention has the following advantages compared with the existing ceramic pigments:

[0069] ① Completely eradicate the toxicity of lead, achieve lead-free, environmentally friendly and healthy.

[0070] ② The baking temperature is low, which can achieve the purpose of energy saving in the reality of increasingly tight energy.

[0071] ③ Cost reduction: There is no need to introduce expensive lithium, and the complicated re-firing process is omitted, which greatly reduces the production cost.

[0072] ④ The obtained pigment has pure color, good gloss, wide firing temperature range, good chemical stability and resistance to acid and alkali corrosion.

[0073] ⑤ The process performance is good and it can be applied to screen printing, flat printing, inkjet printing, hand-painting and repairing and other process methods, with a wide range of applications.

[0074] ⑥ It has a wide range of uses and can be used for the decoration of various ceramic products such as hard porcelain, soft porcelain, stoneware, fine pottery, bone china and glass ceramics, especially suitable for the decoration of lead-free glaze ceramics.

[0075] The ceramic pigment prepared by the preparation method is tested for chemical stability by soaking the ceramic pigment in an acetic acid solution at 25°C and a mass concentration of 5% for 30 hours, or soaking it in a Na2CO3 solution at 25°C and a mass concentration of 0.5% for 50 hours; then observing the hue and color changes of the ceramic pigment. The lead and cadmium dissolution is tested according to the American ASTMC738-1994 standard. After testing, the ceramic pigment prepared by the present invention has the characteristics of high gloss, good chemical stability, pure, clear, bright and realistic color, and no lead or cadmium dissolution.

[0076] The glossiness and color difference of the lead-free, lithium-free, and refire-free ceramic on-glaze screen pigment prepared in one embodiment of the present invention are compared with the pigment obtained by the existing traditional refire process, as shown in the following table:

[0077]

[0078]

[0079] It can be seen from the above comparison that the pigment prepared by the present invention can completely replace the pigment obtained by the traditional double-firing process, greatly simplifying the process and reducing the production cost.

[0080] The above is only a preferred embodiment of the present invention. It should be pointed out that a person skilled in the art can make several modifications and improvements without departing from the inventive concept of the present invention, which all fall within the protection scope of the present invention.

Claims

1. A lead-free, lithium-free, and refire-free ceramic glaze screen pigment, characterized in that: The invention comprises a colorant and a flux, wherein the weight ratio of the colorant to the flux is 8-30%:70-92%; The flux is calculated by weight, and its raw material composition is Includes the following components: 35-75 parts of silicon dioxide SiO2, 3-20 parts of boron trioxide B2O3, 1.5-10 parts of aluminum oxide Al2O3, 1-12 parts of zirconium silicate ZrSiO4, 1-8.5 parts of bismuth trioxide Bi2O3, 1-10 parts of fluorine F and acidic oxides; The colorant is a lead-free colorant.

2. The lead-free, lithium-free, and refire-free ceramic on-glaze screen pigment according to claim 1, characterized in that: The flux also includes the following components by weight: Potassium oxide K2O≤10 parts, sodium oxide Na2O≤10 parts, magnesium oxide MgO≤5 parts, zinc oxide ZnO≤4 parts, calcium oxide CaO≤5.5 parts and barium oxide BaO≤4 parts.

3. The lead-free, lithium-free, and refire-free ceramic on-glaze screen pigment according to claim 2, characterized in that: The acidic oxide is one or more of zirconium dioxide ZrO2, titanium dioxide TiO2 and tin oxide SnO2, wherein the zirconium dioxide ZrO2 is ≤3 parts, the titanium dioxide TiO2 is ≤3 parts, and the tin oxide SnO2 is ≤8.5 parts.

4. The lead-free, lithium-free, and refire-free ceramic on-glaze screen pigment according to claim 3, characterized in that: The flux also includes lanthanum oxide La2O3≤1 part and strontium oxide SrO≤4 parts.

5. A method for preparing the lead-free, lithium-free and refire-free ceramic on-glaze screen pigment as claimed in claim 4, characterized in that: The following steps are involved: S1. preparing flux; S2. Mixing the colorant with the flux prepared above to obtain a powdered pigment.

6. The preparation method according to claim 5, characterized in that: The preparation process of the flux in step S1 is as follows: S101, mixing the raw materials of various components of the flux that have passed through a 80-120 mesh sieve; S102, melting the mixed components at a temperature of 1250-1350° C.; S103, quenching the product obtained after the above melting with cold water, then grinding it by ball milling, and drying it to obtain a flux for use.

7. The preparation method according to claim 6, characterized in that: In step S2, the colorant and the flux are mixed and dry-milled to obtain a finished powder.

8. The preparation method according to claim 7, characterized in that: The particle size of the particles obtained after ball milling in step S103 is less than 5 μm.

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