JP2003212677A - Pottery and method of manufacturing the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide pottery which can exhibit the various effects based on the characteristics as a ferroelectric substance of tourmaline even when the amount of using the tourmaline is decreased and a method of manufacturing the same at low cost. <P>SOLUTION: Glaze containing tourmaline is applied to the body surface of biscuit fired goods and is then fired in a temperature range up to maximum 1,100 to 1,400°C, by which the pottery formed with a coating layer containing tourmaline having the maintained characteristics as the ferroelectric substance is manufactured. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pottery capable of effectively exhibiting the characteristics of tourmaline as a ferroelectric substance, and a method for producing the same.

[0002]

2. Description of the Related Art Ceramics have been widely used for tableware, kitchen utensils, daily necessities and the like. In recent years,
Tourmaline (tourism stone) has been attracting attention as it has a health promoting effect and an environmental cleansing effect, and many products containing tourmaline have been developed.

However, tourmaline is said to lose its potency by changing its composition around 1000 ° C., so there is an example applied to pottery which is subjected to low temperature firing (firing temperature 800 to 900 ° C.). However, there were few examples applied to ceramics that required high temperature firing (firing temperature 1100 to 1400 ° C).

As an example of applying tourmaline to ceramics, a clay for ceramics mixed with tourmaline is molded into a predetermined shape to produce a unglazed product, and then a glaze mixed with tourmaline is applied and then baked at a high temperature. There is a technique for manufacturing (see Japanese Patent Application Laid-Open No. 2001-18
1021).

However, in the above technique, tourmaline is added to the clay for pottery in addition to the glaze component, so that the production cost is high and the firing time is as long as about 10 hours, so that the production capacity is low. there were.

[0006]

In the first place, since the properties of tourmaline as a ferroelectric substance are exhibited substantially only on the surface portion of the product, when applying tourmaline to a ceramic porcelain, There is little need to add tourmaline to. From this point of view, it is most desirable that tourmaline be present in the vitreous coating layer formed on the surface of the ceramic body while maintaining its ferroelectric properties. Further, if such a form can be realized, the amount of tourmaline used can be small, so that the manufacturing cost can be significantly reduced as compared with the conventional technique.

The present invention has been made in view of the above problems, and exhibits various effects based on the characteristics of tourmaline as a ferroelectric even when the amount of tourmaline used is reduced. An object of the present invention is to provide a pottery that can be manufactured and a method for manufacturing such a pottery at low cost.

[0008]

The ceramic of the present invention is a ceramic in which a coating layer containing tourmaline is formed on the surface of the base material of the ceramic, and the characteristics of the tourmaline as a ferroelectric are maintained. It is characterized by

Further, the pottery of the present invention is a pottery in which a coating layer containing tourmaline is formed on the surface of the base material of the pottery, and when water is put in the pottery, it has the action of lowering the redox potential of water. It is characterized by having. Further, the coating layer preferably contains 20 to 40% by weight of tourmaline, and further preferably contains lithium tourmaline (white).

According to the method for producing a porcelain of the present invention, after applying a glaze containing tourmaline to the surface of the base material of the unglazed product,
It is characterized by firing in a temperature range of 1100 to 1400 ° C. at the maximum in a reducing atmosphere. Also, the reducing atmosphere is
The oxygen concentration is preferably 5% or less. In addition, the firing time within the temperature range of 1100 to 1400 ° C. is preferably within 1 hour. The firing time is preferably within 4 hours. In addition, the glaze is 20 ~ tourmaline.
The content is preferably 40% by weight, and more preferably lithium tourmaline (white).

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION In the present invention, when a glaze containing tourmaline is applied to the surface of a base material of a unglazed product to produce a ceramic, by firing the bisque product under a specific condition, It has been completed by finding out that it can be a constituent component of a coating layer formed on the surface of a ceramic body while maintaining the characteristics as a dielectric.

The porcelain of the present invention is manufactured by glazeing the surface of the base material of the unglazed product and then performing the main firing.
Hereinafter, the manufacturing method of the porcelain of the present invention will be described by dividing the items into the unglazed product manufacturing process, the glaze process, and the main baking process, and then the properties of the ceramic product of the present invention will be described.

[Production process of unglazed product] The clay used for the base material of the ceramics of the present invention may be prepared by mixing known materials and kneading the mixture. For example, a plastic raw material is used as a main component, non-plastic raw materials or solvent-based raw materials are appropriately blended, water is added to these raw material blends, finely pulverized with a ball mill or the like to obtain a slurry, and further kneaded with a clay kneader or the like. Also, by deflating the air, it is possible to obtain porcelain clay having a constant water content.

Here, the plastic raw material refers to a raw material that gives plasticity necessary for molding, and in the present invention, clay, kaolin, porcelain stone, bentonite and the like are preferably used. Further, the non-plastic material is a raw material having a function of reducing the shrinkage during drying or firing, preventing the occurrence of cracks, and increasing the mechanical strength of ceramics, and in the present invention, silica (silica, silica) Sand), baked powder, base powder and the like are preferably used. Further, the solvent medium raw material refers to a raw material that lowers the melting point of the compounding base material and promotes the baking of the base material and the generation of the glass phase,
In the present invention, feldspar, limestone, dolomite, talc, bone ash, etc. are preferably used.

Next, using the above clay, a bowl, a tea bowl,
It is molded or molded into various shapes such as incense, incense burner, flower buds, water fingers, scoops, lids, building water, tea vases, tableware for kaiseki dishes (hereinafter simply referred to as "molding"). In the present invention, the method for forming the clay is not particularly limited, and a known method can be used. Further, depending on the forming method, the clay may be used as it is (that is, as the kneaded clay), or water may be added to the kneaded clay to be used as the slurry. For example, slurry casting, solid casting, hand wheel,
A molding method such as mechanical lathe, dry pressing, wet pressing is preferably used. Further, in the present invention, the molded product obtained as described above is preferably dried by natural drying or mechanical drying.

Then, the above-mentioned molded product is put into a unglazed kiln and unglazed. In the present invention, the condition of unglazed is not particularly limited, but generally 800 to 10
It is preferable to perform the treatment within a temperature range of about 00 ° C. for several hours.

[Glazing step] Next, the glazing step of the obtained unglazed product will be described. Glazing is performed by applying glaze to the surface of the base material of the unglazed product. Glaze refers to a raw material for a glass layer used for coating a ceramic body. This glass layer imparts smoothness and luster to the surface of the ceramics, eliminates water absorption, and enhances chemical durability and mechanical strength.

The glaze used in the present invention preferably contains tourmaline and several kinds of glaze raw materials. The glaze raw material is not particularly limited, and when the unglazed product is fired at a high temperature to produce a ceramic, it is usually 1100.
A raw material that melts at a temperature of not less than 0 ° C is preferably used. In the present invention, for example, feldspar, silica sand, kaolin, talc, dolomite, limestone, etc. as a raw material, so that cracks do not occur in the ceramics produced, so that the base material and the coefficient of thermal expansion match, It is preferably used as a formulation having an adjusted chemical composition.

The tourmaline contained in the glaze has a general composition formula of NaX ₃ Al ₆ B ₃ Si ₆ (0,0H) ₃₀ (OH,
F) is an ore represented by X (Mg, Fe, Mn, Li, Al, etc.). In the present invention, the type of tourmaline used as a component of the glaze is not particularly limited, but for example, shawl tourmaline (also referred to as tourmaline).
X; Fe and Mn), magnesia tourmaline (X; Mg), lithium tourmaline (also called lithia tourmaline. X; Li and A)
1) and the like are preferably used. Further, tourmaline may be used as a powder, and the particle size is not particularly limited as long as it does not hinder the preparation of the glaze.

The glaze used in the present invention is used by appropriately mixing the glaze raw material and tourmaline as described above. The mixing ratio of tourmaline to the total amount of glaze can be appropriately changed depending on the degree of expression of physical properties derived from tourmaline required for the ceramics to be produced, and is not particularly limited, but generally 10 to 50 wt% is preferable, 15-45 wt% is more preferable, 20-40
Percentage of importance is particularly preferred. If the compounding ratio of tourmaline is less than 10% by weight, the properties of tourmaline cannot be effectively exhibited, which is not preferable. On the other hand, if the compounding ratio of tourmaline exceeds 50% by weight, the manufacturing cost becomes high, which is not preferable.

Water is added to the glaze prepared as described above to form a slurry, and the glaze is applied to the base material of the unglazed product. The glaze may be applied by a mechanical method or a manual method.

[Main firing step] Next, the main firing step will be described. First, the unglazed product coated with the above glaze is put in a firing kiln. The firing kiln used in the present invention is not particularly limited, and either a single kiln or a continuous kiln can be used, but a continuous kiln (for example, a tunnel kiln or a roller house kiln) is preferable from the viewpoint of the productivity of ceramics. Used.

Further, the firing temperature and time can be appropriately changed depending on the type of kiln used for firing. For example, in the case of using a roller house kiln as a firing kiln, first, gradually heating in a pre-tropical zone, and then in a firing zone under a temperature condition of 1100 to 1400 ° C. at maximum, preferably within 1 hour, More preferably within 40 minutes, particularly preferably 3
A method of firing within 0 minutes and then cooling in a cooling zone is preferable. In this case, the total firing time is preferably about 5 hours, more preferably about 4 hours.

In the present invention, when firing a unglazed product coated with glaze, it is necessary to perform firing in a reducing atmosphere. Here, the "reducing atmosphere" means an atmosphere in which air (that is, oxygen) is not supplied to the kiln as much as possible. In the present invention, the reducing atmosphere preferably has an oxygen concentration of 10% or less, more preferably 8% or less, and particularly preferably 5% or less. As described above, the porcelain of the present invention is manufactured by firing the unglazed product within 1 hour in the temperature range of 1100 to 1400 ° C. in the reducing atmosphere.

The pottery of the present invention has a coating layer containing tourmaline formed on the surface of the base material, and the tourmaline maintains its characteristics as a ferroelectric substance. This is because the melting temperature of tourmaline is 1050-11
It is surprising to consider that the temperature is set to 00 ° C. and the composition change temperature (this temperature is considered to correspond to the “Curie temperature” in the technical field of ferroelectrics) is set to around 1000 ° C. It can be said to be the result.

That is, when the temperature exceeds the Curie temperature, the ferroelectric substance becomes a paraelectric substance because the electric dipole moment becomes disordered, and as a result, the characteristics of the ferroelectric substance disappear.
However, in the present invention, in the firing step, the glaze component other than tourmaline is melted to form the glass layer, and the tourmaline is probably melted, despite being exposed to a temperature condition higher than the melting temperature of tourmaline for a certain period of time. The property as a ferroelectric is maintained without any problem.

There are many unclear points at this time, but it is considered that performing the firing step in a reducing atmosphere is the most important point. This is because in the firing process, when firing is performed in a non-reducing atmosphere (that is, while supplying air), a ceramic is produced in which the characteristics of tourmaline as a ferroelectric substance have disappeared. These results suggest that tourmaline may have some protective action when a glaze component other than tourmaline is hardly oxidized and forms a coating layer as glass.

Further, it is considered that the baking of the unglazed product within a temperature range of 1100 to 1400 ° C. at a maximum in a short time of less than 1 hour also contributes. This is because it is considered that the characteristics of tourmaline as a ferroelectric material disappear even if it is exposed to a high temperature for a long time even under the reducing condition.

[Characteristics of ceramics] Since the ceramics of the present invention has a coating layer containing tourmaline which maintains the characteristics as a ferroelectric substance on the surface of the base material of the ceramics, the characteristics of tourmaline are effectively exhibited. Can be made. That is, since the electrical properties of tourmaline, including piezoelectricity and pyroelectricity, are maintained in the ceramics of the present invention, when water is put in the ceramics of the present invention, water produced by electrolysis of water is reduced. It is expected to reduce the redox potential, activate water, adsorb chlorine odor of water, and impart antibacterial properties.

Specifically, when tap water is added to the ceramics of the present invention, the oxidation-reduction potential of water is immediately lowered. It is said that when tourmaline existing on the surface of a ceramic body comes into contact with water, the water molecules are electrolyzed, and H ⁺ ions are discharged to H ₂ on the electrode surface of the electric dipole moment of tourmaline. That is, the so-called Kubo theory is positively inferred.
This shows that the properties of tourmaline as a ferroelectric substance are maintained.

According to the method for manufacturing a ceramic according to the present invention, since tourmaline is used only on the surface of the base material, the ceramic can be manufactured at a lower cost as compared with the prior art. Furthermore, since the main baking process can be performed within 4 hours, the productivity is improved as compared with the conventional technique.

[0032]

The present invention will be described in more detail with reference to the following examples, but the present invention is not limited thereto.

[Production of unglazed product] A clay material containing 55% by weight of feldspar, 20% by weight of kaolin, and 25% by weight of gyrrome is kneaded with a kneading machine to obtain air-extracted clay having a constant water content. It was Next, using an automatic molding machine, this clay is molded into a drinking tea bowl, and then 1.5
A molded product was obtained by naturally drying for an hour. continue,
The above-mentioned molded product was put in a unglazed kiln and fired at 900 ° C. for 1.5 hours to obtain an unglazed product.

[Glazing Step] A preparation prepared by mixing tourmaline with the raw materials for glaze shown in Table 1 was used as a glaze.
As shown in [Table 2], the blending ratio of tourmaline with respect to the total amount of the glaze was set to be in the range of 20 to 40% by weight. Two types of tourmaline, shawl tourmaline and lithium tourmaline were used. Next, water was added to this glaze to form a slurry, which was applied to the surface of the base material of the unglazed product.

[0035]

[Table 1]

[Main baking process] The unglazed products coated with glaze are loaded on a trolley, placed in a roller house kiln, and gradually heated under conditions of a reducing atmosphere with an oxygen concentration of 5% or less, and then in a firing zone. The porcelain of the present invention was manufactured by firing at a maximum temperature of 1100 to 1400 ° C. for 30 minutes and then rapidly cooling in a cooling zone.

[Measurement of oxidation-reduction potential of water] The manufactured ceramics (Examples 1 to 5) were filled with tap water from Toki City, Gifu Prefecture, and the oxidation-reduction potential immediately after the tap water was put and after 20 minutes. (O
RP) was measured. The results are shown in [Table 2]. In addition, in the present experiment, an ordinary pottery containing the above tap water was used as a comparative example.

From the results shown in [Table 2], the redox potential 20 minutes after tap water was added was
It was lower than immediately after tap water was added. On the other hand, in Comparative Example 1, it was confirmed that the redox potential increased 20 minutes after the tap water was added. From this, it was confirmed that the pottery of the present invention effectively exhibits the action of electrolyzing water when it comes into contact with tap water. Also,
It was also found that when a glaze containing lithium tourmaline (white) was used, the effect of lowering the redox potential was greatest. It is considered that the increase in the redox potential difference in Comparative Example 1 is due to the fact that the tap water is oxidized by the substance existing in the air.

[0039]

[Table 2]

[0040]

As described above, in the ceramic of the present invention, since the coating layer containing tourmaline which maintains the characteristics as the ferroelectric is formed on the surface of the substrate,
Various effects such as lowering the redox potential of water can be effectively exhibited. Further, according to the method for manufacturing a ceramic of the present invention, the main baking step can be performed in a short time, and the amount of tourmaline used can be small,
The productivity can be improved and the manufacturing cost can be significantly reduced as compared with the conventional technology.

Claims (10)

[Claims] 1. A pottery in which a coating layer containing tourmaline is formed on the surface of a base material of the pottery, and the characteristic of the tourmaline as a ferroelectric is maintained. 2. A pottery in which a coating layer containing tourmaline is formed on the surface of a base material of the pottery, which has the action of lowering the redox potential of water when water is put into the pottery. . 3. The ceramic according to claim 1 or 2, wherein the coating layer contains 20 to 40% by weight of tourmaline. 4. The ceramic according to any one of claims 1 to 3, wherein the coating layer contains lithium tourmaline (white). 5. A glaze containing tourmaline is applied to the surface of the base material of the unglazed product, and the maximum temperature is 1100 in a reducing atmosphere.
The manufacturing method of the ceramics characterized by baking in a temperature range of -1400C. 6. The method of manufacturing a ceramic according to claim 5, wherein the reducing atmosphere has an oxygen concentration of 5% or less. 7. The method of manufacturing a ceramic according to claim 5, wherein the firing time in the temperature range of 1100 to 1400 ° C. is within 1 hour. 8. The method of manufacturing a ceramic according to claim 5, wherein the firing step is within 4 hours. 9. The glaze is tourmaline 20 to 40% by weight.
The method for manufacturing a ceramic ware according to any one of claims 5 to 8, characterized by containing. 10. The method for manufacturing a ceramic porcelain according to claim 5, wherein the glaze contains lithium tourmaline (white).