A crackled glaze, a preparation method thereof, and a sanitary ceramic containing the crackled glaze

Abstract

The present invention discloses a crack glaze, a preparation method thereof, and a sanitary ceramics containing the crack glaze. The crack glaze comprises the following raw materials in parts by weight: 1-8 parts of zirconium silicate, 33-38 parts of quartz, 20-25 parts of glass powder, 15-20 parts of calcite, 0.5-5 parts of zircon-type pigment, and 21-50 parts of a flux. The crack glaze of the present invention is a single-layer glaze. The glaze surface is colored by directly adding a zircon-type pigment to the glaze material and cooperating with the addition of zirconium silicate. The thermal expansion coefficient of the glaze is increased by introducing a high proportion of quartz, calcite, and glass powder. The difference in thermal expansion coefficient between the blank and the glaze is utilized to make the glaze surface present a crack-like shape. The generated cracks are stable and the product consistency is high. The present invention simplifies the process flow, reduces the raw material cost, selects non-toxic and environmentally friendly raw materials, and reduces the harm to the human body during the production process.

Description

Technical Field

[0001] The present invention relates to the technical field of sanitary ceramics, and particularly to a crack glaze, a preparation method thereof, and a sanitary ceramic containing the crack glaze. Background Art

[0002] Among ceramic decorative glazes, there is a relatively special glaze called crack glaze. Its glaze surface is covered with many small cracks, and the patterns are sparse or dense, thick or thin, long or short, curved or straight, like tortoise shell cracks, like crab claws, like brocade, like water patterns. These various pattern lines form a unique decoration on the surface of porcelain.

[0003] Crack glaze is mostly used in daily-use ceramics and handicrafts, giving a special aesthetic feeling and having strong ornamental value. With the improvement of economic and cultural levels, people's aesthetics have become increasingly diversified. The sanitary ceramic field is no longer limited to a single bright white color. People prefer products that are both beautiful and practical. More and more colorful glazes have emerged, but the crack glaze that has shown great splendor in other fields has not been applied to the sanitary ceramic field. It is highly feasible to research a crack glaze suitable for the sanitary ceramic field to enhance the decorative effect of the bathroom space.

[0004] At present, there are two types of colored crack glaze products on the market. One is a single-layer glaze colored with metal oxides. However, the disadvantage of coloring with metal oxides is that the formula cost is high because the metal oxides used for coloring are expensive. And it is difficult to present the coloring effect with a single-layer glaze plus ordinary pigments. Therefore, when preparing crack glaze with pigments, a double-layer glaze is mostly used. The double-layer glaze adds color to the bottom glaze, and the top glaze is a transparent glaze. Cracks appear on the glaze surface due to the difference in thermal expansion coefficients between the two glazes, that is, one layer is used for coloring and one layer is used for generating glaze surface cracks. Although the double-layer glaze has a lower raw material cost, its disadvantage is that the process is complex, the process flow is numerous, and the production cost is relatively high.

[0005] In addition, existing crack glazes mostly use toxic raw materials such as lead-containing or barium-containing materials. Lead-containing materials include lead monoxide PbO, lead tetroxide Pb3O4, lead silicate, etc., and barium-containing materials include barium carbonate, barium titanate, etc. Among them, barium carbonate is a white precipitate insoluble in water, which can produce a matte effect and has a strong fluxing effect in high-temperature glazes and can also be used as an opacifier. The functions of lead-containing materials in ceramic glazes usually include promoting vitrification, increasing the gloss of the glaze, changing the color of the glaze, controlling the melting temperature of the glaze, etc. However, the above-mentioned lead-containing or barium-containing raw materials are highly toxic and have certain harm to the human body, which is not conducive to safe production. Summary of the Invention

[0006] The present invention aims to solve at least one of the above technical problems in the related art to some extent. For this purpose, the present invention provides a crack glaze, a preparation method thereof, and a sanitary ceramic containing the crack glaze. The crack glaze can simplify the process flow, reduce the raw material cost, select non-toxic and environmentally friendly raw materials, reduce the harm to the human body during the production process, and is applicable to ordinary sanitary ceramic blanks.

[0007] To achieve the above object, the technical solution of the present invention is as follows:

[0008] The present invention provides a crack glaze, which comprises the following raw materials in parts by weight: 1-8 parts of zirconium silicate, 33-38 parts of quartz, 20-25 parts of glass powder, 15-20 parts of calcite, 0.5-5 parts of zircon type pigment, and 21-50 parts of flux.

[0009] According to some embodiments of the present invention, the flux comprises the following raw materials in parts by weight: 12-20 parts of feldspar, 0-5 parts of wollastonite, 6-12 parts of zinc oxide, 3-8 parts of calcined talc powder, and 0-5 parts of frit. Feldspar, wollastonite, zinc oxide, calcined talc powder, and frit all play a role in fluxing, reducing the melting temperature of the glaze, and at the same time also play a role in stabilizing the formulation composition, keeping the chemical composition of the glaze in a relatively stable range.

[0010] According to some embodiments of the present invention, the zircon type pigment is praseodymium yellow and vanadium zirconium blue with a mass ratio of (0.2-2):(0.5-2). Praseodymium yellow and vanadium zirconium blue can achieve a cyan blue glaze color in the above ratio.

[0011] According to some embodiments of the present invention, the feldspar is at least one of albite or orthoclase. Orthoclase or albite not only plays a role in fluxing, but also plays a role in increasing the thermal expansion coefficient.

[0012] According to some embodiments of the present invention, by mass percentage, the chemical composition of the frit is: 3.7%-4.3% of ZnO, 60.5%-64.7% of SiO2, 6.8%-8.3% of Al2O3, 3.8%-4.6% of K2O, 0.6%-1.3% of Na2O, 16.2%-18.6% of CaO, 0.8%-2.3% of MgO, and 0.1%-0.4% of loss on ignition.

[0013] According to some embodiments of the present invention, by mass percentage, the chemical composition of the crack glaze is: 0.5%-5% of ZrO2, 6%-9% of ZnO, 58%-64% of SiO2, 2%-4% of Al2O3, 1%-3% of K2O, 2%-4% of Na2O, 10%-13% of CaO, 1%-3% of MgO, and 6-10% of loss on ignition.

[0014] According to some embodiments of the present invention, the particle size D50 of the zirconium silicate is 0.9 - 3 μm, and the particle size D50 of the zircon-type pigment is 5 - 9 μm.

[0015] The method for preparing the crack glaze includes the following steps:

[0016] (1) Mix the raw materials according to the ratio, add water, and perform wet grinding to obtain a glaze slurry.

[0017] (2) Apply the glaze slurry on the surface of the green body, and fire it in a kiln to obtain the crack glaze.

[0018] According to some embodiments of the present invention, in step (1), the particle size of the glaze slurry is such that the particles with a size less than 10 μm account for 55% - 65%.

[0019] According to some embodiments of the present invention, in step (2), after applying the glaze slurry, the thickness of the glaze slurry on the surface of the green body is 0.7 - 1.4 mm. Controlling the thickness of the glaze slurry can ensure that the crack glaze can cover the color of the green body while firing a relatively uniform and beautiful crack shape. The thickness of the glaze layer can affect the crack effect on the glaze surface. The thinner the glaze layer, the finer the cracks, but if it is too thin, cracks may not appear on the glaze surface. The thicker the glaze layer, the thicker and sparser the cracks, but if the glaze surface is too thick, the cracks will be unsightly.

[0020] According to some embodiments of the present invention, it further includes an operation of filling ink into the fired glaze surface cracks: after the firing in step (2) is completed, apply the ink on the glaze surface. After the ink dries, wash the glaze surface to obtain a crack glaze with black crack patterns. By applying ink, the glaze surface cracks can be clearly presented, highlighting the crack effect.

[0021] According to some embodiments of the present invention, in step (2), the firing temperature is 1185 - 1210 °C; the firing time is 13 - 18 h.

[0022] A sanitary ceramic contains the crack glaze or the crack glaze prepared by the preparation method.

[0023] According to a preferred embodiment of the present invention, it has at least the following beneficial effects:

[0024] 1. The crackle glaze of the present invention is a single-layer glaze, which is colored by directly adding zircon-type colorants to the glaze and adding zirconium silicate in combination. The colorants used in the present invention are zircon-type colorants in which coloring ions are solid-dissolved in the ZrSiO4 lattice. The glaze has a certain solubility for zirconium silicate. When zirconium silicate is not introduced, the structure of the zircon-type colorant will be destroyed during the firing process, and the coloring ions will volatilize during the firing process, causing the colorant to lose its coloring function and the glaze surface to be unable to be colored. Based on the fact that the particle size of zirconium silicate is finer than that of the colorant, zirconium silicate is introduced into the formula, and the glaze will preferentially dissolve zirconium silicate. After the dissolution is saturated, the colorant structure is maintained and not destroyed during the firing process, thereby utilizing the characteristic that the coloring ions in the zircon-type colorant are solid-dissolved in the ZrSiO4 lattice and still have a significant color ion tone, so that the glaze surface presents the expected color. The zircon-type colorant can be selected from praseodymium yellow and vanadium zirconium blue, and the praseodymium yellow and vanadium zirconium blue are used together to color the glaze surface to present a cyan-blue color, which is more antique.

[0025] 2. The present invention is a single-layer crackle glaze, which increases the thermal expansion coefficient of the glaze by introducing quartz, calcite and glass powder in high proportion, and then makes the glaze surface present a crack shape by using the difference in thermal expansion coefficient between the body and the glaze. On the one hand, the K2O and Na2O in the glass powder and the CaO in the calcite have high contents, and the thermal expansion coefficients of K2O, Na2O and CaO are large, so adding more glass powder and calcite can increase the thermal expansion coefficient of the glaze. On the other hand, when the quartz content in the glaze is high, free quartz can be generated. Free quartz refers to quartz particles that exist independently without combining with other substances. In a glaze system with a high content of quartz, a part of the quartz melts, and the other part exists in the glaze layer in the form of free quartz. The thermal expansion coefficient of free quartz is large, so the introduction of quartz in high proportion can increase the thermal expansion coefficient of the glaze. In addition, glass powder can reduce the performance of glaze, making the glaze strength lower and the thermal expansion coefficient of glaze greater than that of the blank. The glaze is stretched by the blank and produces greater tensile stress. At this time, the tensile stress exceeds the tensile strength of the glaze layer, causing many reticular cracks to form on the glaze. High content of calcite easily precipitates calcium feldspar microcrystals, making the glaze matte, showing more classical charm.

[0026] 3. The raw materials used in the present invention are all conventional raw materials, without toxic raw materials such as lead or barium, which are less harmful to the human body, non-toxic and environmentally friendly, and adopt a single-layer glazing process with a simple process flow and low production cost and formulation cost.

[0027] 4. The present invention uses high silicon and high calcium to increase the thermal expansion coefficient of the glaze to generate cracks. The generated cracks are relatively stable and the product consistency is high. The shape of the cracks is controlled by controlling the thickness of the glaze layer. The cracks are fine and dense where the glaze is thin, and gradually become sparse where the glaze is thick. The crack shapes change from simple to complex, and the cracks are similar but slightly different, presenting a complex, varied, harmonious and unified crack glaze effect, which is very artistic.

[0028] 5. The present invention changes the coloring method of single-layer crack glaze using metal oxides for coloring, and also changes the glazing method of double-layer crack glaze using pigments for coloring. It presents an antique and elegant cyan matte crack glaze effect in a brand-new way that only uses pigments for coloring and applies a single layer of glaze. Applying the highly ornamental matte crack glaze to the field of sanitary ceramics fills the gap of crack glaze in the field of sanitary ceramics, conforms to the trend of fashionization of sanitary ceramics, and provides consumers with more glaze color options.

[0029] 6. The crack glaze of the present invention is applicable to ordinary sanitary ceramic bodies and is fired in the tunnel kiln of ordinary sanitary ceramics. The firing atmosphere is medium-temperature oxidation flame, and it can be fired together with ordinary sanitary ceramic products. The firing cost is low, the product consistency is high, and rapid industrialization can be achieved.

[0030] The additional aspects and advantages of the present invention will be partly given in the following description, partly will become obvious from the following description, or will be understood through the practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] The above and / or additional aspects and advantages of the present invention will become obvious and easy to understand from the description of the embodiments in conjunction with the following drawings, wherein:

[0032] Figure 1 is a physical diagram of Embodiment 2 of the present invention;

[0033] Figure 2 is a physical diagram of Embodiment 3 of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0034] The following will clearly and completely describe the concept of the present invention and the technical effects produced in combination with the embodiments to fully understand the purpose, features and effects of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all embodiments. Other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative efforts belong to the scope of protection of the present invention.

[0035] The technical solution of the present invention is further described in detail below in conjunction with the specific embodiments: For the embodiments and comparative examples of the crack glaze, each component is weighed according to the glaze formula in Table 1.

[0036] Table 1 Crack Glaze Formula

[0037]

[0038] Description: (1) The chemical composition of the frit in Table 1 is: ZnO 3.91%, SiO2 62.29%, Al2O3 7.72%, K2O 4.41%, Na2O 0.88%, CaO 18.01%, MgO 1.92%, loss on ignition 0.33%, impurities 0.53%.

[0039] (2) The chemical composition of the glass powder in Table 1 is: SiO2 71.47%, Al2O3 1.22%, K2O 0.27%, Na2O 13.4%, CaO 8.78%, MgO 3.45%, loss on ignition 0.66%, impurities 0.75%.

[0040] (3) The particle size D50 of the praseodymium yellow in Table 1 is 6.8 μm, the particle size D50 of the vanadium zirconium blue is 7.6 μm, and the particle size D50 of the zirconium silicate is 1.2 μm.

[0041] Chemical composition of the crackle glaze in Table 2

[0042]

[0043] Description: Fe2O3 and TiO2 in Table 2 belong to impurities, and the total impurity content ≤ 1.0%.

[0044] Preparation process of the crackle glaze:

[0045] (1) Prepare the glaze slurry: Mix the formula raw materials according to the ratio in a ball mill, add water, and perform wet ball milling to obtain the glaze slurry; the particle size of the glaze slurry: the particles below 10 μm account for 62%;

[0046] (2) Make the product green body: Make a dry green body with the raw materials of existing ordinary sanitary ceramic slurry;

[0047] (3) Apply the glaze: Apply the glaze slurry on the surface of the dry green body, and the thickness of the glaze slurry on the dry green body surface is 1.0 mm;

[0048] (4) Fire in the kiln: The firing temperature is 1190 °C, and the firing time is 15 h;

[0049] (5) Fill with ink: After the product comes out of the kiln, evenly apply the ink on the glaze surface. When the ink is dry, wash off the ink on the glaze surface with clean water. At this time, the dried ink condenses into blocks and adheres evenly in the glaze cracks, and the ink filling is completed to obtain a crackle glaze sanitary ceramic product with distinct patterns.

[0050] Test example

[0051] After firing the product according to the formula and preparation process in Table 1, use a gloss meter to measure the gloss of the glaze surface, and visually observe the glaze color, color depth, and crack state. The results are shown in Table 3.

[0052] Detection results of the crackle glaze in Table 3

[0053]

[0054] As can be seen from Table 1 and Table 3, Example 1 and Example 2 are the minimum and maximum usage amounts of zirconium silicate, respectively. Example 1 presents a lighter blue-green color, while Example 2 presents the darkest blue-green color. Comparative Example 1 does not add zirconium silicate at all, and the glaze surface is white, indicating that the amount of zirconium silicate content directly affects the depth of the glaze layer color. When there is no zirconium silicate in the glaze, the glaze surface presents a translucent milky white state, the glaze surface is transparent at the thinner glaze layer, and the body color is exposed, which affects the appearance, and no matter how the amount of colorant is increased, the glaze surface does not color; when the colorant ratio is fixed, the higher the zirconium silicate content, the darker the color, and the better the coloring effect of the colorant, because after adding zirconium silicate, the melting of zircon type colorant is suppressed, but there will still be a certain amount of melting, and the more zirconium silicate is added, the less the amount of colorant is destroyed, and the darker the color. Comparative Example 2 uses less quartz, the thermal expansion coefficient of the glaze is lower, the glaze surface has fewer cracks, and some cracks appear. In Comparative Example 3, the amount of calcite used is reduced compared to Example 5, so that the thermal expansion coefficient of the glaze is reduced, the tensile stress of the glaze layer is insufficient, and there are almost no cracks in the thicker glaze layer in the middle of the product. In Comparative Example 4, the amount of glass powder used is reduced compared to Example 7, the thermal expansion coefficient of the glaze is reduced, and the number of cracks on the glaze surface is not as many as in Example 7.

[0055] The embodiments of the present invention are described in detail above in conjunction with the accompanying drawings, but the present invention is not limited to the above embodiments. Various changes can be made within the knowledge of ordinary technicians in the relevant technical field without departing from the purpose of the present invention. In addition, the embodiments of the present invention and the features in the embodiments can be combined with each other without conflict.

Claims

1. A crackle glaze, characterized in that, It comprises the following raw materials in parts by weight: 1-8 parts of zirconium silicate, 33-38 parts of quartz, 20-25 parts of glass powder, 15-20 parts of calcite, 0.5-5 parts of zircon-type pigment, and 21-50 parts of flux; the particle size D50 of the zirconium silicate is 0.9-3 μm, and the particle size D50 of the zircon-type pigment is 5-9 μm.

2. The crackle glaze according to claim 1, characterized in that, The flux comprises the following raw materials in parts by weight: 12-20 parts of feldspar, 0-5 parts of wollastonite, 6-12 parts of zinc oxide, 3-8 parts of calcined talc powder, and 0-5 parts of frit.

3. The crackle glaze according to claim 1, wherein The zircon-type pigment is praseodymium yellow and vanadium zirconium blue with a mass ratio of (0.2-2):(0.5-2).

4. The crackled glaze according to claim 2, wherein By mass percentage, the chemical composition of the frit is: ZnO 3.7%-4.3%, SiO2 60.5%-64.7%, Al2O3 6.8%-8.3%, K2O 3.8%-4.6%, Na2O 0.6%-1.3%, CaO 16.2%-18.6%, MgO 0.8%-2.3%, loss on ignition 0.1%-0.4%.

5. The crackled glaze according to claim 1, characterized in that, By mass percentage, the chemical composition of the crack glaze is: ZrO2 0.5%-5%, ZnO 6%-9%, SiO2 58%-64%, Al2O3 2%-4%, K2O 1%-3%, Na2O 2%-4%, CaO 10%-13%, MgO 1%-3%, loss on ignition 6-10%.

6. The preparation method of the crackle glaze according to any one of claims 1-5, characterized in that, It comprises the following steps: (1) Mix the raw materials according to the ratio, add water, and perform wet grinding to obtain a glaze slurry. (2) Apply the glaze slurry on the surface of the green body, and fire it in a kiln to obtain the crack glaze.

7. The preparation method according to claim 6, characterized in that In step (2), after applying the glaze slurry, the thickness of the glaze slurry on the surface of the green body is 0.7-1.4 mm.

8. The preparation method according to claim 6, characterized in that, It also includes an operation of filling the ink on the fired glaze surface cracks: after the firing in step (2) is completed, apply the ink on the glaze surface, wait for the ink to dry, and then clean the glaze surface to obtain a crack glaze with black crack patterns.

9. A sanitary ceramic, characterized in that, It contains the crack glaze described in any one of claims 1-5 or the crack glaze prepared by the preparation method described in any one of claims 6-8.

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