Glaze, ceramic manufacturing method, and ceramics

Abstract

To provide glazes advantageous for improving hardness, antibacterial and antifouling properties of ceramics, and to provide a technique related to ceramics using the same.SOLUTION: A glaze contains as main components: glass powder; ash; titanium dioxide; borax; kaolin; bone china powder; tin oxide; silica gel powder; zirconium silicate; limonite; dimethylaniline; nano zinc oxide; barium carbonate; and cobalt (III) oxide.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] This disclosure relates to the technical field related to glazes and ceramics.

Background Art

[0002] Ceramics such as porcelain (ceramic products) are generally made by firing a formed body such as a vessel made from inorganic substances such as clay and silica at a high temperature. In particular, when making pottery or porcelain, the formed body is usually fired with a glaze applied to its surface.

[0003] Glazes change into a glassy substance during firing or undergo chemical changes due to heat to acquire a unique color and flavor. Therefore, glazes impart unique designs (decorations) such as texture and color to ceramics, as well as unique functions based on a glass coating or the like.

[0004] For example, the porcelain disclosed in Patent Document 1 has a glaze layer for improving oil-shedding properties and functional retention.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0006] The designs and functions imparted to ceramics by glazes vary depending on the components contained in the glazes. In particular, by using a glaze containing a combination of two or more components with good compatibility, it is possible to impart new design properties and functionality to ceramics. Therefore, it is beneficial to newly propose a glaze containing an appropriate amount of two or more components that have not been conventionally combined.

[0007] Particularly given the growing awareness of hygiene in recent years, the proposal of new glazes that are advantageous in improving hygienic functions such as antibacterial properties and stain resistance that suppress the adhesion of dirt, in addition to the conventionally required properties such as hardness and water resistance (especially glazes that can also improve the design of ceramics), is extremely beneficial.

[0008] This disclosure is made in view of the circumstances described above and aims to provide glazes that are advantageous for improving the hardness, antibacterial properties, and antifouling properties of ceramics, and technologies related to ceramics made using such glazes. [Means for solving the problem]

[0009] One aspect of the present disclosure relates to a glaze mainly composed of glass powder, ash, titanium dioxide, borax, kaolin, bone china powder, tin oxide, silica gel powder, zirconium silicate, limonite, dimethylaniline, nano zinc oxide, barium carbonate, and cobalt(III) oxide.

[0010] The weight ratio of glass powder, ash, and titanium dioxide may be 4-6:3-5:2.

[0011] The above glaze may contain the following components in the following weight ratios: • Glass powder: 4-6 · Ash: 3~5, Titanium dioxide: 2, Borax: 6-8 Kaolin: 8-10 Bone china powder: 3-5 Tin oxide: 2-4 • Silica gel powder: 2-4 • Zirconium silicate: 3-5, Limonite: 4-6, • Dimethylaniline: 1-3 • Nano zinc oxide: 2-4 • Barium carbonate: 3-5, and Cobalt(III) oxide: 1-3.

[0012] Other aspects of the present disclosure relate to a method for manufacturing ceramics, including a step of applying any of the above glazes to a molded body, a step of firing the molded body to which the glaze has been applied, and a step of rapidly cooling the fired molded body.

[0013] Other aspects of the present disclosure relate to ceramics using any of the above glazes.

Advantages of the Invention

[0014] According to the present disclosure, it is advantageous for improving the hardness, antibacterial property, and antifouling property of ceramics.

Brief Description of the Drawings

[0015] [Figure 1] It is a table showing examples of the results of a scratch test and a water absorption test between a glaze containing the components shown in Table 1 (the glaze of this case) and a glaze containing components different from those shown in Table 1 (ordinary glaze). [Figure 2] It is a perspective view of an example of ceramics (ceramic) produced using the glaze of the present disclosure. [Figure 3] It is a perspective view of another example of ceramics produced using the glaze of the present disclosure. [Figure 4] It is a perspective view of another example of ceramics produced using the glaze of the present disclosure. [Figure 5] It is a perspective view of another example of ceramics produced using the glaze of the present disclosure.

Modes for Carrying Out the Invention

[0016] As a result of various trials and errors, the inventor of this case newly found that when the glaze contains glass powder, rice husk ash, and titanium dioxide as main components (especially when it contains glass powder and titanium dioxide as main components), it is advantageous for improving the hardness and antibacterial property of ceramics.

[0017] That is, the inventor of the present invention actually prepared a plurality of glazes with different types and amounts (weights) of contained components, actually produced ceramic products using these glazes, and evaluated the designability and functionality of each ceramic product.

[0018] The ceramic products used for the evaluation were made by preparing a molded body containing clay used as a raw material for ceramics, applying each of the prepared glazes to the surface of the molded body, and firing the molded body with the applied glaze at a high temperature in a kiln.

[0019] Specifically, the molded body was fired in a state without the application of glaze (bisque firing process), the glaze was applied to the molded body that had undergone the bisque firing process (glaze application process), and the molded body was fired in a state with the applied glaze (firing process), thereby producing ceramic products. After the bisque firing process, the molded body was cleaned using ultrasonic waves, and then the glaze application process was performed.

[0020] The designability of each ceramic product was evaluated by sensory evaluation based on the perception of evaluators (especially evaluation experienced persons who have experience in evaluating various ceramic products in the past).

[0021] The functionality of individual ceramic products was evaluated based on the results of various tests conducted using the ceramic products. For example, the hardness (scratch resistance) of ceramic products was evaluated by observing whether or not damage such as scratches occurred when a localized external force was applied to the ceramic product. More specifically, the hardness of the ceramic product was evaluated by pressing a blade against the ceramic product (especially the glazed part) with a force of about 10N, and then moving the blade back and forth on the surface of the ceramic product multiple times over a predetermined width (for example, about four times over a distance of about 10mm), and then observing the scratches on the ceramic product. In addition, the antibacterial properties of ceramic products were evaluated by placing ceramic products treated with a test bacterial solution in a bacterial culture environment for a predetermined time, and then estimating (calculating) the number of viable bacteria based on actual observations. The evaluation of ceramic products was not always performed using the entire finished product; evaluations were also performed using parts of the ceramic product (for example, finely crushed parts (fragments, etc.)).

[0022] The inventors of this case also conducted further functional evaluations of the ceramic product, including evaluations of its thermal stability, lead and cadmium content, microwave oven usability, and oven usability.

[0023] Based on the manufacturing and evaluation methods described above, various ceramic products made using various glazes were evaluated, and the evaluation results of each ceramic product were compared. As a result, the inventors of this study newly discovered that glazes containing glass powder (e.g., waste glass powder), straw ash, and titanium dioxide as main components are particularly advantageous in improving the hardness and antibacterial properties of ceramics.

[0024] In particular, ceramic products using glazes containing the components shown in Table 1 below as the main components showed the best results in terms of the balance between hardness and antibacterial properties, and were also highly evaluated for their design (e.g., the color and texture (roughness, etc.) of the surface of the ceramic product).

[0025] [Table 1]

[0026] Table 1 above shows the content (especially by weight (kg)) of each component in the glaze. In practice, a portion of the glaze, made by uniformly mixing each component shown in Table 1 in the amounts shown in Table 1, was applied to each molded body and used for the manufacture of each ceramic product.

[0027] In Table 1, the unit of content for each component is consistently shown as "kg (kilograms)". Therefore, the weight ratio between components in the glaze can be expressed as the numerical value obtained by removing the units from the content shown in Table 1. In other words, glazes containing the components shown in Table 1 as the main components contain each component in the following weight ratios. • Sepiolite: 20-30 Borax: 6-8 Kaolin: 8-10 Bone china powder: 3-5 • Waste glass powder: 4-6 Tin oxide: 2-4 • Silica gel powder: 2-4 • Zirconium silicate ultrafine powder: 3-5 Limonite: 4-6 • Dimethylaniline: 1-3 • Nano zinc oxide: 2-4 • Barium carbonate: 3-5 doses • Cobalt(III) oxide: 1-3 • Straw ash: 3-5 • Xylene: 8-12, and • Titanium dioxide: 2

[0028] The inventors of this case compared and examined the evaluation results of various ceramic products made using various glazes, and came to the conclusion that the amount (by weight) of waste glass powder (glass powder) and the presence of titanium dioxide (combination of the two) in the glaze have a special effect (i.e., a positive effect) on the ceramic products.

[0029] Figure 1 is a table showing examples of scratch resistance and water absorption rate test results for a glaze containing the components shown in Table 1 (the glaze in question) and a glaze containing different components than those shown in Table 1 (ordinary glaze).

[0030] For example, regarding hardness, ceramic products using glazes containing the components shown in Table 1 above showed only scratches that were barely noticeable even when subjected to localized external force (pressing with a blade) as described above. On the other hand, ceramic products coated with glazes that did not contain the "combination of glass powder, straw ash, and titanium dioxide" as the main components shown in Table 1 showed noticeable scratches when subjected to localized external force as described above, and the scratches were particularly noticeable in ceramic products using glazes that did not contain titanium dioxide. This is thought to be because the titanium dioxide in the glaze, through the firing process, creates a highly stable crystalline structure on the surface of the glaze (i.e., the surface of the ceramic product), which in turn contributes to improving the hardness (improving scratch resistance) of the ceramic product.

[0031] Furthermore, ceramic products using glazes containing the components shown in Table 1 above exhibited excellent water resistance. Generally, ceramic products with low water absorption rates are less prone to staining and stains that do adhere are easier to remove, thus possessing superior stain resistance. Ceramic products with a water absorption rate of approximately 0.5% or less are often considered to have standard water resistance. As shown in Figure 1, the water absorption test results indicate that the glaze containing the components shown in Table 1 (water absorption rate = 0.29%) has superior water resistance compared to the ordinary glaze (water absorption rate = 0.31%).

[0032] Furthermore, when firing the glaze onto a molded body, rapidly cooling the molded body (i.e., the ceramic product) immediately after firing under desired conditions can more effectively increase the hardness of the ceramic product and maintain the suspension of the glaze by avoiding precipitation or separation. Specifically, in the case of a ceramic product using the ordinary glaze shown in Figure 1, the firing process of the molded body after glaze application was carried out at a maximum temperature of approximately 1250°C for about 20 minutes, and then the fired molded body (i.e., the ceramic product) was allowed to cool naturally for about 18 hours. On the other hand, in the case of a ceramic product using the glaze in question (a glaze containing the components shown in Table 1), the firing process of the molded body after glaze application was carried out at a maximum temperature of approximately 1250°C for about 50 minutes, and then the fired molded body (i.e., the ceramic product) was rapidly cooled to approximately 1100°C (specifically in about 10 seconds), and then allowed to cool naturally.

[0033] The inventors prepared multiple molded bodies coated with the same glaze as shown in Figure 1, fired these bodies under the same conditions (at a temperature of approximately 1250°C for approximately 50 minutes), and then varied the degree of rapid cooling for each body. As a result, when the temperature of the fired molded bodies was rapidly cooled to a range of approximately 50°C to 250°C, preferably approximately 120°C to 180°C (i.e., when the fired molded bodies were rapidly cooled from approximately 1250°C to approximately 1000°C to 1200°C, preferably approximately 1070°C to 1130°C), the hardness of the ceramic products could be increased particularly effectively, and the suspendability of the glaze could be maintained while avoiding precipitation and separation of the glaze. While the rate of rapid cooling is not necessarily limited, performing the rapid cooling described above to lower the temperature of the molded body after firing by an average of approximately 5°C to 25°C per second, for example, approximately 10°C to 20°C (approximately 15°C as an example), yielded good results in terms of hardness of the ceramic product, avoidance of glaze precipitation and separation, and maintenance of glaze suspension.

[0034] Regarding thermal stability, lead and cadmium content, microwave and oven usability, ceramic products using glazes containing the components shown in Table 1 above showed standard or better evaluation results. For example, when ceramic products were rapidly heated and cooled between -20°C and 160°C, no damage such as cracks was observed in ceramic products using the glazes in Table 1. Furthermore, the lead and cadmium content of ceramic products using the glazes in Table 1 were both within safe limits. In addition, when ceramic products were used in an environment where a heating energy of 72,000 J (joules) was applied by a microwave oven with an output of 600 W, no damage such as cracks was observed in ceramic products using the glazes in Table 1, and no discharge phenomena occurred. Furthermore, when ceramic products were placed in a high-temperature environment of 230°C in an oven for 2 hours, no abnormalities such as cracks, discoloration, or deformation were observed in ceramic products using the glazes in Table 1.

[0035] Figures 2 to 5 are perspective views of examples of ceramics 10 produced using the glazes of this disclosure.

[0036] The design of the ceramic 10 to which the glaze of this disclosure can be applied is not limited. For example, the glaze of this disclosure can be effectively used when making a relatively flat and shallow plate as shown in Figure 2, a shallow plate as shown in Figure 3 with a rim rising from the bottom upwards, a bowl as shown in Figure 4 with a relatively large depth, and a plate as shown in Figure 5 with a relatively large depth and a rim extending both in the height direction and the horizontal direction.

[0037] The ceramics on which the glaze disclosed herein can be used are not limited, and the glaze disclosed herein may be used in ceramics for any application other than plates (see Figures 2 to 5).

[0038] Furthermore, the manufacturing method of ceramic products is not limited. For example, each component that will be used as a raw material for the glaze may be weighed out in the desired weight, the weighed raw material components (see Table 1 above) may be thoroughly and uniformly stirred and mixed, and the mixed glaze raw materials may be fired one or more times (e.g., twice) in a high temperature environment (e.g., about 1100°C). In this case, the fired raw materials may be ball-milled and crushed to a desired fineness (e.g., 300-350 mesh) to create a glaze slip of the desired concentration, and this glaze slip may be applied to a molded body. The molded body to which the glaze slip has been applied may be heated to a desired high temperature (e.g., about 1100-1400°C) in a kiln using an oxidizing or reducing flame and fired. By performing these series of steps, ceramic products can be manufactured.

[0039] It should be noted that the embodiments and modifications disclosed herein are illustrative in all respects and should not be construed restrictively. The embodiments and modifications described above may be omitted, substituted, and modified in various ways without departing from the scope and spirit of the appended claims. For example, the embodiments and modifications described above may be combined in whole or in part, and other embodiments may be combined with the embodiments or modifications described above. Furthermore, the effects described herein are illustrative, and other effects may result. [Explanation of Symbols]

[0040] 10 Ceramics

Claims

1. Glass powder, ash, titanium dioxide, borax, kaolin, bone china powder, tin oxide, silica gel powder, zirconium silicate, limonite, dimethylaniline, nano zinc oxide, barium carbonate, and cobalt(III) oxide are contained in the following weight ratios: • Glass powder: 4-6 ・ Ash: 3-5, Titanium dioxide: 2, Borax: 6-8 Kaolin: 8-10 Bone china powder: 3-5 Tin oxide: 2-4 • Silica gel powder: 2-4 • Zirconium silicate: 3-5, Limonite: 4-6 • Dimethylaniline: 1-3, • Nano zinc oxide: 2-4 • Barium carbonate: 3-5, and Cobalt(III) oxide: 1-3 glaze.

2. A step of applying the glaze described in claim 1 to a molded body, A step of firing the molded body to which the glaze has been applied, A method for manufacturing ceramics, comprising the step of rapidly cooling the molded body after firing.

3. A ceramic using the glaze described in claim 1 or 2.

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