A method for preparing frit, dry granules, and flannel ceramic tiles.

Abstract

This invention discloses a frit, dry granules, a method for preparing the dry granules, and flannel ceramic tiles, relating to the field of ceramic technology. The chemical composition of the frit, by mass percentage, is: Al₂O₃ 17–20%, SiO₂ 55–62%, CaO 5.0–5.5%, MgO 0.15–0.22%, K₂O 4.8–5.2%, Na₂O 6.5–7.0%, BaO 0.09–0.11%, ZnO 0.9–1.1%, Li₂O 0.2–0.3%, F 0.08–0.1%, SrO 0.1–0.2%, with the balance being loss on ignition. Because of its special composition ratio, this frit has a matte finish and high melt viscosity, making it difficult to level. When spherical dry granules are prepared from this frit, they can maintain their spherical shape during sintering and melting. Therefore, ceramic tiles with a dry granule layer can form tiny protrusions on the tile surface. These protrusions can increase the diffuse reflection of light, improve the matte effect of the tile, and also enhance its color. Importantly, when the surface of the tile is touched by hand, these protrusions have a flannel-like feel, giving the tile a skin-friendly touch.

Description

Technical Field

[0001] This invention relates to the field of ceramic technology, and in particular to a frit, dry granules, a method for preparing dry granules, and flannel ceramic tiles. Background Technology

[0002] Higher gloss levels on tile surfaces generally make them easier to clean. However, excessive brightness can lead to strong glare, causing discomfort and making matte tiles increasingly popular. Current matte tiles are typically polished to a gloss level below 10. At this level, there is no reflective effect, resulting in a better texture and slip resistance. However, matte tiles achieved through polishing have a rougher feel, are more prone to dirt accumulation, are harder to clean, lack a skin-friendly feel, and fail to meet consumers' tactile requirements.

[0003] It is evident that existing technologies still need improvement and enhancement. Summary of the Invention

[0004] In view of the shortcomings of the prior art, the purpose of this invention is to provide a frit, dry granules, a method for preparing dry granules, and flannel ceramic tiles, aiming to solve the defect that ceramic tiles with a matte effect in the prior art do not have a skin-friendly feel.

[0005] To achieve the above objectives, the present invention adopts the following technical solution:

[0006] The first aspect of the present invention provides a frit, wherein, by mass percentage, the chemical composition of the frit is: Al2O3 17-20%, SiO2 55-62%, CaO 5.0-5.5%, MgO 0.15-0.22%, K2O 4.8-5.2%, Na2O 6.5-7.0%, BaO 0.09-0.11%, ZnO 0.9-1.1%, Li2O 0.2-0.3%, F 0.08-0.1%, SrO 0.1-0.2%, with the balance being loss on ignition.

[0007] A second aspect of the present invention provides a dry granule, wherein the dry granule is prepared from the melt as described above, and the dry granule is a spherical or hemispherical powder particle.

[0008] The dry granules have a particle size of 40–60 μm.

[0009] The third invention provides a method for preparing dry granules, the method comprising: taking frit particles, ball milling and sieving to obtain frit powder; taking frit powder, additives and water, ball milling and mixing to obtain a mixed slurry; and granulating the mixed slurry through a centrifugal spray drying tower to obtain dry granules.

[0010] In the method for preparing the dry granules, the particle size of the fused powder is ≤6.5μm.

[0011] In the method for preparing the dry granules, the additives include sodium hydroxymethyl cellulose and sodium tripolyphosphate.

[0012] In the method for preparing the dry granules, the solid content in the mixed slurry is 45wt% to 55wt%.

[0013] In the method for preparing the dry granules, during granulation, the rotation speed of the spray head of the centrifugal spray drying tower is 12000-15000 r / min.

[0014] In the method for preparing the dry granules, the temperature inside the centrifugal spray drying tower is 250–350°C.

[0015] A fourth aspect of the present invention provides a flannel ceramic tile, wherein the surface of the ceramic tile is provided with a dry granule layer, the dry granule layer being prepared from the dry granules as described above.

[0016] Beneficial effects:

[0017] This invention provides a frit, dry granules, a method for preparing the same, and flannel-textured ceramic tiles. The frit is a frit with a special composition ratio, particularly the content and ratio of Al2O3 and SiO2, which gives the frit a matte finish and high melt viscosity, making it less prone to leveling. Spherical dry granules are prepared from this frit, which maintain their spherical shape during sintering and melting. Therefore, ceramic tiles with a dry granule layer can form fine protrusions on the tile surface. These protrusions can increase the diffuse reflection of light, improve the matte effect of the tile, and also enhance its color. Importantly, when the tile surface is touched by hand, these protrusions have a flannel-like feel, giving the tile a skin-friendly texture. Attached Figure Description

[0018] Figure 1 The image shows a physical example of the flannel ceramic tile provided by this invention. Detailed Implementation

[0019] This invention provides a frit, dry granules, a method for preparing dry granules, and flannel ceramic tiles. To make the objectives, technical solutions, and effects of this invention clearer and more explicit, the following embodiments are provided to further illustrate the invention in detail. It should be understood that the specific embodiments described herein are only for explaining the invention and are not intended to limit the invention.

[0020] The first aspect of the present invention provides a frit that can be used to prepare dry granules or as a glaze material for a surface glaze layer. The chemical composition of the frit, by mass percentage, is: Al2O3 17-20%, SiO2 55-62%, CaO 5.0-5.5%, MgO 0.15-0.22%, K2O 4.8-5.2%, Na2O 6.5-7.0%, BaO 0.09-0.11%, ZnO 0.9-1.1%, Li2O 0.2-0.3%, F 0.08-0.1%, SrO 0.1-0.2%, with the balance being loss on ignition. The mass ratio of alumina to silicon dioxide in the frit is between 1:3 and 1:4, resulting in a matte finish. Simultaneously, the high content of SiO2 and Al2O3 in the frit leads to high viscosity during melting. When the frit is prepared into dry granules, the high viscosity allows the granules to maintain a spherical shape at high temperatures, forming protrusions on the tile surface and providing a skin-friendly feel. To lower the melting temperature of the frit, its chemical composition also contains a certain amount of K2O and Na2O, both high-temperature fluxes that reduce the melting temperature and consequently lower the firing temperature of the tile. Furthermore, because the frit is prepared by high-temperature calcination followed by quenching, it has low bubble content and good chemical stability. When the frit is prepared into dry granules and distributed on the tile surface, it forms a transparent, bubble-free granular layer with fine protrusions that create diffuse reflection, resulting in a matte finish and a skin-friendly feel.

[0021] In a preferred embodiment, the chemical composition of the frit, by mass percentage, is: Al₂O₃ 18.5%, SiO₂ 60.0%, CaO 5.2%, MgO 0.2%, K₂O 5.0%, Na₂O 6.7%, BaO 0.1%, ZnO 1.0%, Li₂O 0.3%, F 0.1%, SrO 0.2%, with the balance being loss on ignition. This chemical composition results in a frit with a better matte finish and a more skin-friendly feel.

[0022] The above-mentioned frit preparation method is as follows: take the raw material components for frit preparation, melt them at a high temperature of 1350-1500℃ for 1-2 hours, then quench them in cold water, dry them and grind them to obtain frit.

[0023] The raw materials for preparing the frit include: calcined kaolinite, potassium feldspar, sodium feldspar, calcite, fluorite, alumina, lithium oxide, barium carbonate, zinc oxide, and strontium oxide. The specific proportions of each raw material are adjusted according to the actual composition of the frit to obtain a frit with the target chemical composition.

[0024] The second aspect of the present invention also discloses a dry granule, which is prepared from the frit as described above. Therefore, the dry granule also has a matte effect, has a high viscosity when melted, and is a spherical or hemispherical powder particle. When it is applied as a crystal to the surface of the glaze layer or the surface of the tile, these spherical or hemispherical dry granule particles can form smooth, fine protrusions on the surface of the glaze layer or the tile. These fine protrusions can form diffuse reflection, which on the one hand can give the tile surface a matte effect and also enhance its color, and on the other hand, it has a skin-friendly feel when touched by hand.

[0025] Besides the shape of the dry granules affecting their tactile feel, the particle size also influences it. When the particle size is small, it tends to level out during melting, making it difficult to form fine protrusions on the surface. Conversely, when the particle size is large, it tends to form larger protrusions, resulting in a rougher surface texture and reduced skin-friendly feel. Therefore, in a preferred embodiment, the particle size is 40–60 μm. The protrusions formed after sintering dry granules within this size range exhibit a better matte finish, a finer texture, and a better skin-friendly feel.

[0026] The third aspect of the present invention also provides a method for preparing dry granules, wherein the dry granules are as described above. The preparation method includes the following steps: taking fused particles, ball milling and sieving them to obtain fused powder; taking fused powder, additives and water, and ball milling them in a planetary ball mill to obtain a mixed slurry; granulating the mixed slurry through a centrifugal spray drying tower to obtain spherical dry granules with a particle size of 40-60 μm.

[0027] In the above-mentioned method for preparing dry granules, the particle size of the frit powder affects the preparation of spherical dry granules. When the particle size of the frit powder is too large, it is difficult to form spherical dry granules with small particle size and dense packing. Experiments have shown that when the particle size of the frit powder is less than 6.5 μm, the resulting spherical dry granules have a smaller particle size and better skin-friendly effect. Therefore, in a preferred embodiment, the frit is ball-milled and then sieved with a 2000-mesh sieve to ensure that the particle size of the obtained frit powder is less than or equal to 6.5 μm.

[0028] To ensure the frit powder is well dispersed in water and prevents sedimentation, while also enabling the frit powder particles to agglomerate into spherical particles during drying, additives are added to the mixed slurry. These additives include sodium tripolyphosphate and methylcellulose. The sodium tripolyphosphate helps to uniformly disperse the frit powder in water, forming a homogeneous mixed slurry. The sodium methylcellulose has a good binding effect, allowing the droplets to form spherical particles during the drying process when the slurry is sprayed into the drying tower. This ensures that the frit powder particles within the spherical particles are tightly bonded together, allowing the high viscosity of the frit itself to continue to maintain the spherical shape during subsequent melting, thus forming smooth protrusions.

[0029] The solid content in the mixture affects the particle size and distribution of the dry granules. A higher solid content results in a wider particle size distribution and a larger average particle size, while a lower solid content leads to a narrower particle size distribution and a smaller average particle size. This is mainly because a higher solid content results in a higher density of sprayed droplets, leading to greater friction with the air. Consequently, some droplets are sheared and broken, forming finer particles, thus resulting in a wider particle size distribution. However, an excessively wide particle size distribution can cause a rough surface finish and uneven diffuse reflection of light, resulting in a less than ideal matte effect. In a preferred embodiment, the solid content of the mixed slurry is 45wt% to 55wt%. Under optimal conditions, the dry powder prepared from the mixed slurry with this solid content has a particle size of 40 to 60 μm and a narrow particle size distribution. The resulting dry granule layer has a good matte effect. Furthermore, due to the narrow particle size distribution, the dry powder particles are more uniform in size, and the resulting protrusions are also more uniform, resulting in a better skin-friendly feel.

[0030] During spray drying, the mixed slurry is subjected to centrifugal force through the spray head. Therefore, the rotational speed of the spray head also affects the particle size of the final dry powder. Generally, the lower the rotational speed of the spray head, the larger the droplet size and the lower the shear force of the droplets in the drying tower, resulting in larger particle sizes and a narrower particle size distribution. Conversely, the higher the rotational speed of the spray head, the smaller the sprayed slurry will form droplets. Due to the faster rotational speed of the droplets in the drying tower and the greater shear force, there is a possibility of shearing and splitting, resulting in dry powder with smaller particle sizes and a wider particle size distribution. To obtain dry powder with smaller particle sizes and a narrower particle size distribution, in a preferred embodiment, during the centrifugal spray drying process, when the rotational speed of the spray head is 12000–15000 r / min and the solid content of the slurry is 45wt%–55wt%, the particle size of the dry powder can be 40–60 μm.

[0031] Furthermore, the temperature inside the drying tower affects the shape of the dried granules. When the temperature inside the drying tower is too high, the granules are prone to hollowing or defects due to rapid evaporation of moisture, resulting in irregular shapes and an inability to form a dense structure. Consequently, the matte and skin-feel effects of the dried granule layer formed on the tile surface are reduced. Conversely, when the temperature inside the drying tower is too low, it is difficult to dry the droplets into solid granules in a short time. Therefore, the droplets tend to clump together during the descent, preventing the formation of granular material. To obtain well-shaped spherical dried granules, in a preferred embodiment, during centrifugal spray drying in step S2, the temperature inside the drying tower is 250–350°C, combined with a spray head rotation speed of 12,000–15,000 r / min, which can form spherical dried granules with a particle size in the range of 40–60 μm.

[0032] The dry granules prepared by the above method can form a matte layer when applied to the surface of the glaze or the surface of the tile. They can achieve a gloss level of 3 to 8 degrees without polishing. The dry granules also have a fine texture with raised bumps that can form good diffuse reflection, resulting in a matte finish and color enhancement. Furthermore, they have a skin-friendly feel when touched.

[0033] A fourth aspect of this invention also provides a flannel ceramic tile, the surface of which is provided with a dry granule layer. This dry granule layer is obtained by spreading the dry granules as described above onto the tile surface and then sintering them. This dry granule layer can form smooth protrusions on the tile surface. These protrusions not only increase the diffuse reflection of the tile surface, giving it a matte effect, but also provide a skin-friendly feel, similar to flannel when touched. Furthermore, since the frit used to prepare the dry granules is a matte frit, the tile surface can have a matte effect with a gloss level of 3-8°. Moreover, due to its good transparency, the texture and color of the bottom are well displayed, making it popular with users (e.g., Figure 1 (As shown).

[0034] In addition, the tile also includes a body layer, a base glaze layer disposed on the body layer, a pattern layer disposed on the base glaze layer, and a top glaze layer disposed on the pattern layer. The base glaze layer is used to cover the color of the body layer to improve the color development of the pattern layer. The pattern layer, disposed on the base glaze layer, can be a pattern or color printed onto the base glaze layer by inkjet printing or a pattern texture printed onto the base glaze layer by screen printing, which enhances the decorative effect of the tile. The top glaze layer, disposed on the pattern layer, protects the pattern layer, has good transparency, and allows the pattern layer to be displayed well, resulting in a better decorative effect. The dry granule layer, disposed on the top glaze layer, can form raised areas on the tile surface, thus providing a matte and skin-friendly effect. Furthermore, these raised areas increase diffuse reflection, enhancing color and making the colors of the pattern layer more vivid. More importantly, touching these raised areas provides a flannel-like feel.

[0035] To ensure the dry granule layer protrudes well onto the surface glaze layer, the surface glaze layer is prepared using a high-temperature, low-viscosity glaze. In a preferred embodiment, the chemical composition of the surface glaze layer, by mass percentage, is as follows: SiO2 48.8%, Al2O3 17.5%, K2O 2.3%, Na2O 4.6%, CaO 9.8%, MgO 3.1%, ZnO 5.5%, BaO 3.8%, ZrO2 0.1%, with the remainder being loss on ignition. The surface glaze layer has a matte finish and high transparency, allowing for better display of the pattern in the pattern layer. Simultaneously, due to the high flux content in the surface glaze layer's chemical composition, it has a low melting temperature and low viscosity, resulting in good leveling properties, allowing the dry granule layer to protrude more effectively from the surface and providing a better skin-friendly experience.

[0036] The steps for preparing the flannel ceramic tile are as follows:

[0037] Step A1. Form a base glaze layer on the surface of the body;

[0038] Step A2. Print a pattern layer on the surface of the base glaze layer;

[0039] Step A3. Apply a top coat of glaze to the surface of the pattern layer to obtain the top coat of glaze.

[0040] Step A4. Apply dry granules to the surface of the glaze layer to obtain a dry granule layer;

[0041] Step A5. Sintering and molding to obtain flannel ceramic tiles.

[0042] To further illustrate the present invention, which provides a frit, dry granules, a method for preparing dry granules, and flannel ceramic tiles, the following embodiments are provided.

[0043] Example 1

[0044] A frit, by mass percentage, has the following chemical composition: Al₂O₃ 18.5%, SiO₂ 60.0%, CaO 5.2%, MgO 0.2%, K₂O 5.0%, Na₂O 6.7%, BaO 0.1%, ZnO 1.0%, Li₂O 0.3%, F 0.1%, SrO 0.2%, with the balance being loss on ignition.

[0045] Example 2

[0046] A frit, by mass percentage, has the following chemical composition: Al₂O₃ 17%, SiO₂ 62%, CaO 5.0%, MgO 0.15%, K₂O 4.8%, Na₂O 6.5%, BaO 0.09%, ZnO 0.9%, Li₂O 0.2%, F 0.08%, SrO 0.1%, with the balance being loss on ignition.

[0047] Example 3

[0048] A frit, by mass percentage, has the following chemical composition: Al₂O₃ 20%, SiO₂ 55%, CaO 5.5%, MgO 0.22%, K₂O 5.2%, Na₂O 7.0%, BaO 0.11%, ZnO 1.1%, Li₂O 0.3%, F 0.1%, SrO 0.2%, with the balance being loss on ignition.

[0049] Example 4

[0050] A dry pellet, which is prepared from the frit as described in Example 1.

[0051] The preparation method of the dry granules is as follows: take the fused particles, ball mill them, and pass them through a 2000-mesh sieve to obtain fused powder; take the fused powder, additives, and water, put them into a planetary ball mill and ball mill them to obtain a mixed slurry with a solid content of 50%; spray the mixed slurry into a centrifugal spray drying tower for granulation, wherein the rotation speed of the spray head is 13200 r / min, the temperature inside the drying tower is 310℃, the flow rate is 5L / h, and spherical dry granules with an average particle size of 52μm are obtained after drying.

[0052] Example 5

[0053] A dry pellet, which is prepared from the frit as described in Example 2.

[0054] The preparation method of the dry granules is as follows: take the fused particles, ball mill them, and pass them through a 2000-mesh sieve to obtain fused powder; take the fused powder, additives, and water, put them into a planetary ball mill and ball mill them to obtain a mixed slurry with a solid content of 45%; spray the mixed slurry into a centrifugal spray drying tower for granulation, wherein the rotation speed of the spray head is 15000 r / min, the temperature inside the drying tower is 350℃, the flow rate is 5L / h, and spherical dry granules with an average particle size of 40μm are obtained after drying.

[0055] Example 6

[0056] A dry pellet, which is prepared from the frit as described in Example 3.

[0057] The preparation method of the dry granules is as follows: take the fused particles, ball mill them, and pass them through a 2000-mesh sieve to obtain fused powder; take the fused powder, additives, and water, put them into a planetary ball mill and ball mill them to obtain a mixed slurry with a solid content of 55%; spray the mixed slurry into a centrifugal spray drying tower for granulation, wherein the rotation speed of the spray head is 12000 r / min, the temperature inside the drying tower is 250℃, the flow rate is 5L / h, and spherical dry granules with an average particle size of 60μm are obtained after drying.

[0058] Example 7

[0059] A flannel ceramic tile, comprising a tile body layer, a base glaze layer, a pattern layer, a top glaze layer, and a dry granule layer, wherein the dry granule layer is prepared from the dry granules described in Example 4.

[0060] Example 8

[0061] A flannel ceramic tile, comprising a tile body layer, a base glaze layer, a pattern layer, a top glaze layer, and a dry granule layer, wherein the dry granule layer is prepared from the dry granules described in Example 5.

[0062] Example 9

[0063] A flannel ceramic tile, comprising a tile body layer, a base glaze layer, a pattern layer, a top glaze layer, and a dry granule layer, wherein the dry granule layer is prepared from the dry granules described in Example 6.

[0064] Comparative Example 1

[0065] A type of ceramic tile with a layered structure that is basically the same as that of Example 7, except that it does not have a dry granule layer.

[0066] Comparative Example 2

[0067] A ceramic tile with a layered structure basically the same as that of Example 7, except that the chemical composition of the frit used to prepare the dry granules in its dry granule layer is: SiO2 48.0%, Al2O3 17.5%, K2O 3.5%, Na2O 4.2%, CaO 7.1%, MgO 2.2%, ZnO 5.6%, BaO 5.2%, with the remainder being loss on ignition.

[0068] Comparative Example 3

[0069] A type of ceramic tile with a layered structure that is basically the same as that in Example 7, except that the particle size of the dry particles used to prepare its dry granule layer is 20 μm.

[0070] Comparative Example 4

[0071] A ceramic tile with a layered structure that is basically the same as that in Example 7, except that the particle size of the dry particles used to prepare its dry granule layer is 100 μm.

[0072] Performance testing

[0073] The flannel ceramic tiles described in Examples 7-9 and the ceramic tiles described in Comparative Examples 1-4 were subjected to performance tests, including tests on gloss, color development (color depth), and surface texture. Gloss was tested using a gloss meter, measuring multiple points and calculating the average gloss. Color development was tested using a colorimetric method on the same color. Surface texture was tested by touch. Specific test results are shown in Table 1.

[0074] Table 1. Performance Comparison Table

[0075]

[0076] As shown in Table 1, the gloss of the flannel tiles described in Examples 1 to 3 is between 3 and 8. The colors are pure, and they have a good matte effect, a delicate feel, and a skin-friendly touch. This is because a dry granule layer is provided on the surface glaze layer. The dry granule layer consists of spherical particles with special chemical composition and particle size. After sintering, it can form protrusions on the surface of the tile. These protrusions can increase diffuse reflection, making the colors of the pattern layer more vibrant. At the same time, these protrusions have a good tactile feel and a skin-friendly effect. In Comparative Example 1, the absence of a dry granule layer prevented the formation of a skin-friendly feel, and the smooth, flat surface with increased gloss was due to the leveling effect of the glaze layer during sintering. In Comparative Example 2, the chemical composition of the dry granules used differed from that of Example 1, with excessively high flux content, resulting in lower melting temperature and viscosity. Consequently, the surface of the tile could not form microscopic protrusions during sintering, thus lacking a skin-friendly feel. In Comparative Example 3, the smaller particle size of the dry granules made it difficult to achieve a noticeable skin-friendly feel. In Comparative Example 4, the excessively large particle size resulted in a rough tile surface, failing to achieve a good skin-friendly feel.

[0077] In the description of the embodiments of the present invention, it should also be noted that, unless otherwise explicitly specified and limited, the terms "set" and "connection" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection, a direct connection, or an indirect connection through an intermediate medium; or they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in the present invention based on the specific circumstances.

[0078] It is understood that those skilled in the art can make equivalent substitutions or modifications to the technical solution and inventive concept of the present invention, and all such substitutions or modifications should fall within the protection scope of the appended claims.

Claims

1. A type of dry granules, characterized in that, The dry granules are prepared from frit, and the chemical composition of the frit, by mass percentage, is: Al2O3 17-20%, SiO2 55-62%, CaO 5.0-5.5%, MgO 0.15-0.22%, K2O 4.8-5.2%, Na2O 6.5-7.0%, BaO 0.09-0.11%, ZnO 0.9-1.1%, Li2O 0.2-0.3%, F 0.08-0.1%, SrO 0.1-0.2%, with the balance being loss on ignition; The dry granules are spherical or hemispherical powder particles with a particle size of 40–60 μm.

2. A method for preparing dry granules as described in claim 1, characterized in that, The preparation method includes: taking frit particles, ball milling and sieving to obtain frit powder; taking frit powder, additives and water, ball milling and mixing to obtain a mixed slurry; and granulating the mixed slurry through a centrifugal spray drying tower to obtain dry granules.

3. The method for preparing dry granules according to claim 2, characterized in that, The particle size of the frit powder is ≤6.5μm.

4. The method for preparing dry granules according to claim 2, characterized in that, The additives include sodium hydroxymethyl cellulose and sodium tripolyphosphate.

5. The method for preparing dry granules according to claim 2, characterized in that, The solid content in the mixed slurry is 45wt% to 55wt%.

6. The method for preparing dry granules according to claim 2, characterized in that, During granulation, the rotational speed of the spray head in the centrifugal spray drying tower is 12000-15000 r / min.

7. The method for preparing dry granules according to claim 2, characterized in that, The temperature inside the centrifugal spray drying tower is 250–350°C.

8. A flannel ceramic tile, characterized in that, The surface of the ceramic tile is provided with a dry granule layer, which is prepared from the dry granules as described in claim 1.

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