KR102579865B1 - Method for manufacturing salt tile and salt tile - Google Patents

Abstract

The present invention relates to a method for manufacturing salt tiles and salt tiles accordingly. The method for manufacturing salt tiles includes the following steps: a) mixing salt powder and water glass solution to prepare a mixture; b) press molding the mixture to produce a solid; c) applying a waterproofing agent containing soluble silicate to one surface of the solid material; and d) drying the solid material to which the waterproofing agent has been applied, curing the material two or more times by gradually increasing the temperature, and then further curing the material one or more times by lowering the temperature.

Description

Manufacturing method of salt tile and salt tile {METHOD FOR MANUFACTURING SALT TILE AND SALT TILE}

The present invention relates to a method of manufacturing salt tiles and salt tiles.

Recently, not only do we save resources to preserve the global environment, but we also try to protect human health from harmful chemicals, heavy metals, and environmental hormones absorbed into the human body, as well as environmental pollution caused by air pollution and fine dust caused by industrialization. Construction materials and supplies, such as red clay mats and charcoal mats, are widely used.

However, the above products are produced by attaching powders of specific ingredients to non-woven fabrics, etc. with adhesives or by chemical coating, so the efficacy and effectiveness are significantly low and the powders of the above specific ingredients scatter from the surface when used for a certain period of time. There are problems such as:

Accordingly, salt tiles are being used as an eco-friendly building material, and the salt tiles are manufactured with salt, which can be used for food, as the main ingredient, and can be used for healthcare purposes. Salt tiles for this purpose are mainly used with a salt content of more than 80% of the total tile content.

However, salt tiles containing more than 80% of the salt content have a high production rate of defective products due to breaking or breaking due to lack of strength during the production process, and produced salt tiles melt in a high temperature and humidity environment, causing deformation of the product. In addition, there are problems in that durability is significantly reduced.

Accordingly, there is a demand for a method of manufacturing salt tiles that have excellent strength and improved durability by preventing deformation in various environments.

KR 10-0794322 B1 (2008.01.07)

The purpose of the present invention is to improve the strength of salt tiles, continuously exhibit excellent durability even in high-temperature and high-humidity environments, and provide salt tiles and a method for manufacturing salt tiles that exhibit antibacterial and deodorizing effects.

In order to achieve the above object, the present invention includes the steps of a) mixing salt powder and water glass solution to prepare a mixture; b) press molding the mixture to produce a solid; c) applying a waterproofing agent containing soluble silicate to one surface of the solid material; and d) drying the solid material to which the waterproofing agent has been applied, curing the solid material at least two times by gradually raising the temperature, and then further curing the solid material at least once by lowering the temperature.

In addition, the present invention provides a salt tile containing salt and silica, wherein a waterproofing agent layer containing soluble silicate is formed on one side of the salt tile.

The salt tile according to the present invention has the advantage of significantly improving the interfacial properties of each composition, showing excellent strength, and significantly improving durability as problems such as deformation do not occur even in high temperature and high humidity environments.

In addition, the salt tile according to the present invention has a waterproofing agent layer containing soluble silicate formed on one side, so it can continuously demonstrate excellent durability.

Even if the effect is not explicitly mentioned in the present invention, the effect described in the specification expected by the technical features of the present invention and the inherent effect thereof are treated as if described in the specification of the present invention.

Unless otherwise defined, the technical and scientific terms used in this specification have the meanings commonly understood by those skilled in the art in the technical field to which this invention pertains, and the following description and accompanying drawings describe the present invention. Descriptions of known functions and configurations that may unnecessarily obscure the point are omitted.

Additionally, as used herein, the singular forms “a,” “an,” and “the” are intended to include the plural forms as well, unless the context clearly dictates otherwise.

In addition, units used without special mention in this specification are based on weight, and as an example, the unit of % or ratio means weight % or weight ratio, and weight % refers to the amount of any one component of the entire composition unless otherwise defined. It refers to the weight percent occupied in the composition.

In addition, the numerical range used in this specification includes the lower limit and upper limit and all values within the range, increments logically derived from the shape and width of the defined range, all double-limited values, and numerical ranges defined in different forms. Includes all possible combinations of upper and lower limits. Unless otherwise specified in the specification of the present invention, values outside the numerical range that may occur due to experimental error or rounding of values are also included in the defined numerical range.

The term 'comprise' in this specification is an open description with the same meaning as expressions such as 'comprising', 'contains', 'has' or 'characterized by', and includes elements that are not additionally listed, Does not exclude materials or processes.

In addition, the term 'substantially' in this specification means that other elements, materials or processes not listed together with the specified element, material or process may impermissibly affect at least one basic and novel technical idea of the invention. It means that it can be present in an amount or degree that does not have a significant effect.

The method for manufacturing salt tiles of the present invention includes the steps of a) mixing salt powder and water glass solution to prepare a mixture; b) press molding the mixture to produce a solid; c) applying a waterproofing agent containing soluble silicate to one surface of the solid material; and d) drying the solid material to which the waterproofing agent has been applied, curing the solid material at least two times by gradually increasing the temperature, and then further curing the solid material at least once by lowering the temperature.

The salt powder may be one or more types selected from the group consisting of fine salt, coarse salt, rock salt powder containing iron, and refined salt powder.

The finely divided salt may have an average particle size (D ₅₀ ) of 1 to 10 ㎛, specifically 1 to 8 ㎛, and more specifically 1 to 5 ㎛. In addition, the coarsely divided salt may have an average particle size (D ₅₀ ) of 100 to 300 ㎛, specifically 150 to 300 ㎛, and more specifically 200 to 300 ㎛. The fine powder salt and coarse salt may be distinguished according to particle size, and for example, commercially available sea salt may be used.

In this specification, the average particle size and average particle diameter “D ₅₀ ” mean the particle size corresponding to 50% of the volume accumulation. The D ₅₀ can be measured using, for example, a laser diffraction method. The laser diffraction method is generally capable of measuring particle sizes ranging from the submicron region to several millimeters, and can obtain results with high reproducibility and high resolution.

The iron-containing rock salt powder may have an average particle size (D ₅₀ ) of 10 ㎛ to 500 ㎛, and for example, commercially available Himalayan ground rock salt pink salt may be used.

The refined salt may refer to refined salt with a sodium chloride content of 99% (w/w) or more, specifically 99.5% (w/w) or more. For example, commercially available Hanju Salt (Hanju Co., Ltd.) may be used.

In step a), a mixture is prepared by mixing salt powder and water glass solution. Through the process of mixing salt powder and water glass, the salt powder particles can be uniformly dispersed, and the salt powder can exhibit strong bonding properties through the water glass. Specifically, the water glass may refer to an aqueous solution of sodium silicate with a solid content of 15 to 30% by weight. When mixing the salt powder with the water glass, the water glass may serve as a binder. In particular, when the salt powder contains two or more types of salt, the water glass can reduce the interfacial tension between the two or more types of salt particles. For example, when the salt powder contains both fine salt and coarse salt, the water glass can not only significantly reduce the interfacial tension between the fine salt and coarse salt particles, but also provide strong bonding and fusion between each particle. By making it easy, each of the particles can be combined with high bonding force.

On the other hand, when salt tiles are manufactured by mixing sodium silicate powder, not water glass, with the salt powder, pressurizing and heating, due to the high interfacial tension between different particles, bonding and harmonization between the compositions are difficult to achieve, and the Even if the mixture is molded under press molding conditions according to the present invention, a problem occurs in which the strength is significantly reduced.

The mixture may include 5 to 30 parts by weight of water glass, specifically 5 to 20 parts by weight, based on 100 parts by weight of salt powder. In the above range, water glass can better perform the role of a binder, so that the salt powder can be compression molded with stronger binding force and can also exhibit high strength even after compression molding. The water glass is described based on a water glass solution with a solid content of 30% by weight.

Through the press molding process of the mixture described above in step b), it can be compression molded to have a specific shape. The press molding method is not particularly limited, but specifically, a hydraulic press molding device may be used. Specifically, the press molding process may be performed at a pressure of 70 MPa or more. For example, it can be performed by pressing with a 250-ton hydraulic press for 10 to 60 seconds, specifically 20 to 50 seconds.

The mold used during the press molding may have a circular, oval, or polygonal shape, but is not limited thereto. In addition, the average thickness of the salt tile produced by the mold may be 100 to 500 mm, specifically 100 to 300 mm, and more specifically 120 to 200 mm. Salt tiles manufactured to have the above thickness range may not easily break or break.

In step c), a process of applying a waterproofing agent containing soluble silicate is performed on one surface of the press-molded solid.

The salt tile manufacturing method of the present invention can provide continuous durability to the salt tile by applying a waterproofing agent containing soluble silicate to one surface of the solid material. When a waterproofing agent containing the soluble silicate is applied to one surface of the solid, it can penetrate between the salt particles of the solid and improve the density between salt particles, thereby forming a physical coating or film on the salt tile. Without changing the surface appearance of the salt tile, the effect of improving durability due to the application of the waterproofing agent can be continuously increased over time.

The waterproofing agent containing the soluble silicate may be a natural concrete waterproofing agent, and is specifically used for concrete containing soluble silicates having a pH of 11 to 12, a specific gravity (25°C) of 1.100 to 1.200, and a viscosity (25°C) of 30 cps or less. It may be an inorganic penetrating waterproofing agent.

The method of applying the waterproofing agent containing the soluble silicate may be applied, sprayed, or sprayed, and is not particularly limited as long as the method can properly apply the waterproofing agent containing the soluble silicate to one surface of the solid material. The waterproofing agent containing the soluble silicate may be applied in an amount of 0.05 L to 0.5 L, specifically 0.1 L to 0.4 L, and more specifically 0.2 L to 0.3 L, per 1 m ² of the area of the solid material. It can be. If the amount of the waterproofing agent used is too low, it is difficult to expect the waterproofing effect and durability improvement effect due to the formation of the calcium silicate hydrate, and if the amount of the waterproofing agent used is excessive, an excessive amount of soluble silicate will remain, which will affect the surface appearance of the salt tile. It may have a negative effect or cause a decrease in durability.

In step d), the solid material coated with the waterproofing agent is dried. A curing step is performed, which makes it possible to manufacture salt tiles with high strength. Specifically, the drying may be performed at room temperature and humidity of 40 to 50% for 24 hours, but is not limited thereto.

Next, the salt tile targeted by the present invention can be manufactured through the process of curing the initially dried mixture.

In the salt tile manufacturing method of the present invention, the curing process is performed by gradually increasing the temperature and curing at least two times, then lowering the temperature and performing additional curing at least once.

Raising the temperature stepwise means that the temperature does not rise gradually, but that the temperature of each curing process increases stepwise with a gap. Specifically, the temperature gap of each curing process is 5℃ or more, 5℃. to 50°C, 5°C to 30°C, or 5°C to 20°C. For example, after primary curing at 40°C for 3 hours, the temperature may be raised to 55°C and secondary curing at 55°C for 10 hours may be performed.

The process of gradually raising the temperature and curing the temperature may be performed in a temperature range of 30°C to 150°C, specifically in a temperature range of 35°C to 120°C, and more specifically in a temperature range of 35°C to 100°C. It can be performed at a temperature range of °C. Additionally, the process of gradually raising the temperature and curing the temperature may be performed for a total of 10 to 25 hours, and specifically, may be performed for 12 to 20 hours. The process of gradually raising the temperature and curing the temperature may be performed two or more times, specifically 2 to 8 times, and more specifically 3 to 6 times.

In one example of the present invention, the process of curing the temperature by gradually increasing the temperature includes primary curing at 30°C to 45°C for 1 hour to 4 hours, and secondary curing at 45°C to 65°C for 8 hours to 10 hours. It may include curing, a third curing process of 2 to 4 hours at 65℃ to 77℃, and a fourth curing process of 1 hour to 3 hours at 77℃ to 150℃, and each stage of the curing process is performed at a temperature of 5℃ or higher. There may be temperature differences.

In addition, in one example of the present invention, the process of curing the temperature by gradually increasing the temperature includes primary curing at 37°C to 45°C for 2 to 4 hours and curing at 50°C to 60°C for 8 to 10 hours. It may include a secondary curing process, a 3rd curing process of 2 to 4 hours at 70℃ to 77℃, and a 4th curing process of 1 hour to 3 hours at 77℃ to 85℃, and the curing process at each stage is 5 There may be a temperature difference of ℃ to 20 ℃.

In addition, after the process of gradually increasing the temperature and curing the temperature, the step of lowering the temperature and performing additional curing one or more times is performed. The step of lowering the temperature and performing additional curing one or more times may be performed at a temperature that is 30°C or more lower than the immediately preceding curing temperature, and specifically may be performed at a temperature that is 32°C or more lower than the immediately preceding curing temperature. Specifically, it can be performed at a temperature that is 35°C or more lower than the previous curing temperature. The step of lowering the temperature and performing additional curing one or more times may be performed in a temperature range of 30°C to 60°C.

The step of additional curing by lowering the temperature may be performed one or more times, specifically 1 to 4 times, and more specifically 1 to 3 times. Additionally, the final curing step may be a step of natural cooling at room temperature. The additional curing step by lowering the temperature may be performed for a total of 10 to 20 hours, and the additional curing may include cooling time at room temperature.

The curing can increase the bending strength of the press-molded salt tile and prevent the problem of salt powder scattering on the surface of the salt tile when used for a long time.

In the method for producing salt tiles according to the present invention, the mixture may further include one or more selected from the group consisting of zeolite, illite, charcoal, and red clay, and specifically, based on 100 parts by weight of the salt powder, It may contain 1 to 15 parts by weight, specifically 2 to 10 parts by weight, of one or more types selected from the group consisting of zeolite, illite, charcoal, and red clay.

In addition, specifically, when the mixture further includes charcoal, it may include 1 to 7 parts by weight of the charcoal, specifically 2 to 6 parts by weight, based on 100 parts by weight of the salt powder, and the mixture may include red clay. When included, 3 to 9 parts by weight of the red clay may be included, specifically 4 to 8 parts by weight, based on 100 parts by weight of the salt powder.

In the above range, the problem of lowering the dispersibility of zeolite does not occur, so not only can a sufficient moisture absorption effect be achieved, but in the case of a mixture of the zeolite, the surface roughness of the salt tile is reduced, thereby increasing the surface uniformity of the tile, and reducing friction. Desorption of powder decreases. Specifically, the type of the zeolite is not particularly limited, but examples include salts containing metal ions such as sodium, potassium, calcium, strontium, and barium. Specifically, it may be [K,Na][(AlO ₂ )(SiO ₂ )]nH ₂ O or Na[(AlO ₂ )(SiO ₂ )]nH ₂ O, but is not limited thereto.

When illite is included in the above range, it can exhibit a radioactivity removal effect by efficiently adsorbing radioactive substances such as cesium and radon.

When the charcoal is included in the above range, the deodorizing effect can be achieved more effectively.

The red clay may be powdered red clay, and contains SiO ₂ , Al ₂ O ₃ , and Fe ₂ O ₃ as main components, including 40 to 70% by weight of SiO ₂ and 10 to 30% by weight of Al ₂ O ₃ . It may contain 20% by weight of Fe ₂ O ₃ 5 and 1 to 10% by weight of other components such as CaO, MgO, K ₂ O, Na ₂ O, and TiO ₂ . When the red clay is included in the above range, the antibacterial effect can be further exerted, and the dehumidification and deodorization effects can be further improved.

The present invention also provides salt tiles manufactured by the above manufacturing method.

The salt tile of the present invention is a salt tile containing salt and silica, and the salt tile has a waterproofing agent layer containing soluble silicate formed on one surface.

Hereinafter, the present invention will be described in detail through examples. However, these are intended to illustrate the present invention in more detail, and the scope of the present invention is not limited to the following examples.

Example 1

A mixture was prepared by mixing 650 g of Shinan sea salt with an average particle size (D ₅₀ ) of 200 ㎛ as coarse salt and 130 g of water glass solution with a solid content of 30%, and then injecting the mixture into a mold and using a hydraulic press. A solid product was manufactured by compression molding for 40 seconds using a 250-ton hydraulic press.

After applying Bangsuli NS-100 (Youngil Chemical Co., Ltd.), an inorganic penetrating waterproofing agent, to one side of the solid material in an amount of 0.3 L/m ² using an air spray, the solid material coated with the waterproofing agent was placed under conditions of 25°C and 45% humidity. It was dried for 24 hours.

The dried solid was cured sequentially at 40℃ for 3 hours, 55℃ for 10 hours, 75℃ for 3 hours, and 80℃ for 2 hours, then at 45℃ for 3 hours, and then at room temperature (25℃) for 10 hours. After curing for a while, a salt tile with a thickness of 150 mm and a size of 200 × 110 mm was finally manufactured.

Example 2

A mixture was prepared by mixing 640 g of Hanju Salt (Hanju Co., Ltd.) as refined salt and 85.3 g of water glass solution with a solid content of 30%. The mixture was injected into a mold and then pressed with a 250-ton hydraulic press for 30 seconds. Compression molding was performed to produce a solid material.

After applying Bangsuli NS-100 (Youngil Chemical Co., Ltd.), an inorganic penetrating waterproofing agent, to one side of the solid material in an amount of 0.3 L/m ² using an air spray, the solid material coated with the waterproofing agent was placed under conditions of 25°C and 45% humidity. It was dried for 24 hours.

The dried solid was cured sequentially for 3 hours at 40℃, 9 hours at 55℃, 3 hours at 75℃, and 2 hours at 80℃, then cured at 45℃ for 3 hours, and then cured at room temperature (25℃) for 10 hours. After curing for a while, a salt tile with a thickness of 150 mm and a size of 200 × 110 mm was finally manufactured.

Example 3

Example 2 above, except that 620 g of crushed Himalayan rock salt pink salt (D ₅₀ 400 ㎛) was used as a rock salt powder containing iron instead of refined salt, and the amount of water glass solution with a solid content of 30% was changed to 82.7 g. Salt tiles were manufactured in the same manner as above.

Example 4

A mixture was prepared by mixing 615 g of fine salt with an average particle size (D ₅₀ ) of 5 ㎛ and 61.5 g of a water glass solution with a solid content of 30%. The mixture was injected into a mold, and then 250 tons of water was pressed using a hydraulic press. A solid was manufactured by compression molding for 40 seconds using a hydraulic press.

After applying Bangsuli NS-100 (Youngil Chemical Co., Ltd.), an inorganic penetrating waterproofing agent, to one side of the solid material in an amount of 0.3 L/m ² using an air spray, the solid material coated with the waterproofing agent was placed under conditions of 25°C and 45% humidity. It was dried for 24 hours.

The dried solid was cured sequentially for 3 hours at 40℃, 8 hours at 55℃, 2 hours at 75℃, and 1 hour at 80℃, then cured at 45℃ for 3 hours, and then cured at room temperature (25℃) for 10 hours. After curing for a while, a salt tile with a thickness of 150 mm and a size of 200 × 110 mm was finally manufactured.

Example 5

Salt tiles with a thickness of 150 mm and a size of 200Х110 mm were manufactured in the same manner as in Example 1, except that 58.5 g of zeolite was additionally mixed during the preparation of the mixture in Example 1.

Example 6

A salt tile with a thickness of 150 mm and a size of 200 × 110 mm was manufactured in the same manner as in Example 1, except that 58.5 g of illite was additionally mixed during the preparation of the mixture in Example 1.

Example 7

A salt tile with a thickness of 150 mm and a size of 200 × 110 mm was manufactured in the same manner as in Example 1, except that 32.5 g of charcoal powder was additionally mixed during the preparation of the mixture in Example 1.

Example 8

A salt tile with a thickness of 150 mm and a size of 200 × 110 mm was manufactured in the same manner as in Example 1, except that 45.5 g of red clay powder was additionally mixed during the preparation of the mixture in Example 1.

Example 9

A mixture was prepared by mixing 320 g of Hanju Salt (Hanju Co., Ltd.) as refined salt, 308 g of fine powder salt with an average particle size (D ₅₀ ) of 5 ㎛, and 73.3 g of water glass solution with a solid content of 30%, and injecting the mixture into a mold. Afterwards, compression molding was performed for 25 seconds using a 250-ton hydraulic press to produce a solid product.

After applying Bangsuli NS-100 (Youngil Chemical Co., Ltd.), an inorganic penetrating waterproofing agent, to one side of the solid material in an amount of 0.3 L/m ² using an air spray, the solid material coated with the waterproofing agent was placed under conditions of 25°C and 45% humidity. It was dried for 24 hours.

Cured the dried solid sequentially at 40℃ for 3 hours and 10 minutes, 55℃ for 9 hours and 30 minutes, 75℃ for 3 hours and 10 minutes, and 80℃ for 2 hours and 10 minutes, then cured at 45℃ for 3 hours and 10 minutes. Then, it was cured at room temperature (25°C) for 10 hours and 30 minutes to finally produce salt tiles with a thickness of 150 mm and a size of 200 × 110 mm.

Comparative Example 1

It was prepared in the same manner as in Example 1 except that sodium silicate powder was used instead of the water glass solution.

Comparative Example 2

A mixture was prepared by mixing 500 g of fine salt with an average particle size (D ₅₀ ) of 5 ㎛, 200 g of Shinan sea salt with an average particle size (D ₅₀ ) of 200 ㎛ as coarse salt, and 60 g of water glass solution with a solid content of 30%. After adding the mixture to the mold, compression molding was performed at a pressure of 70 MPa using a hydraulic press. After drying for 24 hours at 25°C and 45% humidity, the salt tiles were cured at 100°C for 5 hours to produce salt tiles with a final thickness of 200 mm and a size of 200 x 110 mm.

Experiment example

Bending strength and durability evaluation

The bending strength of the salt tiles manufactured according to Examples 1 to 4 and Comparative Examples 1 and 2 was measured according to the KS F 4419 standard, and after being left for 7 days (168 hours) at 40°C and 80% humidity, the bending strength was measured again. Measurements were made and the results are shown in Table 1.

Bending strength (MPa) Immediately after manufacturing After left for 7 days at 40℃ and 80% humidity Example 1 5.2 5.1 Example 2 4.9 4.9 Example 3 4.8 4.8 Example 4 5.6 5.5 Comparative Example 1 2.6 1.5 Comparative Example 2 3.7 3.1

As can be seen in Table 1, the salt tile manufactured according to the present invention continued to maintain its initial strength even after being left in a high temperature and high humidity environment for 7 days, but in the case of Comparative Examples 1 and 2, the bending strength value decreased significantly. can confirm.

Claims (14)

) Preparing a mixture by mixing salt powder and water glass solution;
b) press molding the mixture to produce a solid;
c) applying a waterproofing agent containing soluble silicate to one surface of the solid material; and
d) drying the solid material to which the waterproofing agent has been applied, curing it at least two times by gradually raising the temperature, and then further curing it at least once by lowering the temperature,
The process of curing the temperature by gradually increasing the temperature includes primary curing at 30°C to 45°C for 2 to 4 hours, secondary curing at 45°C to 65°C for 8 hours to 10 hours, and 65°C to 77°C. A method of manufacturing salt tiles comprising a 3rd curing process of 2 to 4 hours and a 4th curing process of 1 hour to 3 hours at 77°C to 150°C, where each stage of the curing process has a temperature difference of 5°C or more. .
According to claim 1,
The salt powder is a method of producing a salt tile, wherein the salt powder is at least one selected from the group consisting of fine salt, coarse salt, rock salt powder containing iron, and refined salt powder.
According to claim 2,
The fine powdered salt is a method of producing salt tiles having an average particle size (D ₅₀ ) of 1 to 10 ㎛.
According to claim 2,
The coarse salt is a method of producing a salt tile with an average particle size (D ₅₀ ) of 100 to 300 ㎛.
According to claim 1,
A method of manufacturing a salt tile, wherein the salt tile includes 80 parts by weight to 90 parts by weight based on 100 parts by weight of the salt powder.
According to claim 1,
A method of manufacturing a salt tile by applying 0.05 L to 0.5 L of a waterproofing agent containing the soluble silicate with respect to 1 m ² of the area of the solid material.
According to claim 1,
A method of producing a salt tile, wherein the mixture includes 5 to 30 parts by weight of a water glass solution containing 30% by weight of solid content, based on 100 parts by weight of salt powder.
According to claim 1,
The mixture further includes 1 to 15 parts by weight of at least one selected from the group consisting of zeolite, illite, charcoal, and red clay, based on 100 parts by weight of the salt powder.
According to claim 1,
A method of manufacturing salt tiles in which the process of gradually increasing the temperature and curing the temperature is performed for a total of 10 to 25 hours in a temperature range of 30 ℃ to 150 ℃.
delete According to claim 1,
A method of manufacturing salt tiles in which the process of lowering the temperature and performing additional curing one or more times is performed for a total of 10 to 20 hours at a temperature that is at least 30°C lower than the previous curing temperature.
According to claim 1,
A method of manufacturing salt tiles in which the step of lowering the temperature and further curing at least once is performed in a temperature range of 30°C to 60°C.
A salt tile manufactured by the manufacturing method of any one of claims 1 to 9 or 11 to 12.
delete