JP2001048658A - Method for firing humidity-conditioning plate material - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enhance decorative design properties and fouling resistance of a fired humidity- conditioning plate material while retaining its high humidity-conditioning performance by glazing the surface of a platelike green body formed from a raw material containing a humidity-conditioning raw material, or a biscuit-fired body of the green body and then firing the glazed body so that the color of the inside of the resulting fired body is darker than that of a surface layer of the body, to form the fired plate material. SOLUTION: In the above firing method, preferably, a dark-colored zone having a brightness value equivalent to <=80% of that of the outermost surface side and a thickness equivalent to 20-90% of the thickness of the fired body, exists inside the fired body. Also, as the raw material, pumice derived from volcanic pumice layers in various areas, diatomaceous earth, acid clay, activated clay, zeolite, halloysite and/or sepiolite can be used. Such a raw material, if necessary, is mixed with clay or a glassy component and then the raw material (mixture) is formed into a platelike green body and the green body is fired to obtain a fired body and to form the objective fired humidity-conditioning plate material, wherein optionally, the green body is glazed and then the glazed body is fired, or the green body is subjected to biscuit firing and then the biscuit-fired body is glazed and thereafter the glazed body is fired, by adjusting the firing temperature and the firing time in such a way that the higher the firing temperature, the shorter the firing time, the glazed body can be fired so that the color of the inside of the fired body is darker than that of the surface layer and preferably, in order to retain high humidity-conditioning performance of the fired body after glazing.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for sintering a humidifying board such as a humidifying building material, and more particularly, to a humidifying building material having an improved design due to its surface being glazed and having improved stain resistance. The present invention relates to a method for sintering a humidity control plate material suitable for sintering.

[0002]

2. Description of the Related Art Conventionally, Japanese houses have realized a building with good humidity control and dew-proofing properties by using wooden earthen walls.
In recent years, buildings have become more airtight, and new building materials that emphasize fire resistance and airtightness have come to be used frequently. However, the new building materials have the following problems due to insufficient properties such as humidity control and dewproofing.

(1) By dew condensation on the surface of building materials,
Impairs the comfort and durability of the building. (2) Moisture generated by dew condensation causes mold and mites to develop, which has an adverse effect on the human body.

In order to solve these problems, an air conditioner is generally installed. However, the air conditioner requires power and is not preferable in terms of not only the equipment cost but also the operation cost.

[0005] Therefore, development of a humidity control building material which has a humidity control function to the building material itself, adjusts the humidity of the room without requiring air conditioning equipment or power, and obtains dew-proofing property has been developed. Is being done. Conventionally, as a humidity control building material, a building material obtained by mixing a material having hygroscopicity such as zeolite or diatomaceous earth with a hardening material such as cement or gypsum or a clay or the like and firing it is used. . Specifically, diatomaceous earth-based humidity control building materials are disclosed in JP-A-4-354514 and zeolite-based humidity control materials are disclosed in JP-A-3-1514.
No. 09244 has been proposed.

[0006] Heretofore, there has not been provided a humidity control building material which is obtained by firing and whose surface is glazed. This is because the surface of the humidity control building material is covered with the glaze glass layer by the glaze, and the humidity control performance is lost.

[0007]

SUMMARY OF THE INVENTION In a conventional humidity control building material,
Since no glaze is applied in order to ensure the humidity control performance in this way, the decorating method is limited and the width of the design is narrow. In addition, there is a drawback that dirt such as hand marks is easily attached, and it is difficult to remove the once attached dirt.

An object of the present invention is to solve the above-mentioned conventional problems and to provide a method for sintering a humidity control plate having a high humidity control ability. Another object of the present invention is to provide a method of firing a humidity control plate material such as a humidity control building material having an improved design property by glazing the surface and having improved stain resistance.

[0009]

According to the present invention, there is provided a method for sintering a humidified plate material, comprising a step of sintering a plate-like molded body of a raw material containing a humidified raw material or an unglazed body thereof. It is characterized in that it is fired so that the color becomes darker.

[0010] In this case where the brightness distribution in the thickness direction of the cross section of the sintered body was measured, the dark portion of 80% or less of the lightness L _A relative lightness L _A most surface is present inside the said heat- The thickness of the dark portion is 20 to 95 times the thickness of the fired body.
%.

[0011] By sintering such that the inside becomes dark, a humidity control plate having high humidity control ability can be obtained. If it is baked strongly (for example, at a high temperature or for a long time) so that the inside becomes the same color as the surface layer, the humidity control plate obtained has a low humidity control ability.

The reason why the humidity control plate material obtained by firing in this way has excellent humidity control performance is not necessarily clear, but the inside of the fired body is more distant from the surface layer due to the oxidation / reduction atmosphere during firing. This is presumed to be due to a fine structure suitable for humidity control.

In the method of sintering the humidity control plate material of the present invention, it is preferable to sinter the coated plate-shaped raw material after glazing or to sinter the unglazed body. Since the surface of the humidity control plate material obtained by firing in this manner is glazed, various decorations with glaze can be given, and the width of the design can be expanded.

Further, the glazed surface is hardly stained by hand marks and the like, and can be easily removed even if stained, so that the surface can be kept clean.

When the surface of the humidity control plate material is glazed, the rate of moisture absorption and desorption of the humidity control plate material is slightly reduced, but the capacity of the humidity control plate material is hardly changed. Is not greatly impaired.

The glaze is formed so that the glass layer formed by the glaze is formed in an area of 90% or less of the surface of the humidity control building material main body, or the maximum thickness of the glass layer is 30%.
It is preferable that the humidity control is performed so as to be 0 μm or less, and the humidity-controlled building material after glazing preferably has a humidity control performance of 80% or more of the humidity-controlled building material main body before glazing.

The humidity control plate material obtained by the method of the present invention comprises:
It is preferable that the moisture absorption / release performance in an 8-hour cycle is 80 g / m ² or more. That is, in a house, it is necessary to cope with short-term fluctuations such as humidity generation due to cooking, bathing, heating, and the like, and humidity fluctuations based on daily-level temperature fluctuations. For this purpose, it is necessary that the rate of moisture absorption and desorption is high. The Hygroscopic performance of 8-hour cycle 80 g / m ² or more (as Hygroscopic performance of 24-hour cycles 140 g / m ² or more) This requirement is met by the. In addition, the moisture absorption / release performance of this 8-hour cycle is obtained as follows. Relative humidity 5
The weight is made constant in a thermo-hygrostat maintained at 0% (fluctuation of 0. 1%).
(1% or less) is quickly put into another constant temperature / humidity chamber maintained at a relative humidity of 90%, and the weight increase (moisture absorption (g)) after 8 hours is converted into a unit area (1 m ² ). The value obtained is taken as the moisture absorption for 8 hours. In addition, a test specimen whose weight was made constant (variation of 0.1% or less) in a thermo-hygrostat kept at 90% relative humidity was quickly put into another thermo-hygrostat kept at 50% relative humidity. Weight loss after 8 hours (moisture release (g))
Is converted per unit area (1 m ² ) to 8 hours of moisture release. Then, it is obtained by the following equation. 8 hour cycle moisture absorption / desorption performance = (8 hour moisture absorption + 8 hour moisture removal) / 2

[0018]

Embodiments of the present invention will be described below in detail.

In the present invention, examples of the humidity control raw material include volcanic pumice layers, diatomaceous earth, acid clay, activated clay, zeolite, halloysite, sepiolite and the like, which are called Kanuma soil, Osawa soil and colloid soil, water soil, and miso soil. Moisture-controlling raw materials. If necessary, clay such as Kibushi clay, Frogme clay, quartzite, pottery stone, rubble, feldspar and other vitreous components are mixed with the humidified raw material, and extruded or pressed to obtain a molded product. Is fired. The molded body may be glazed and fired, or the molded body may be fired to form a unglazed body, and the unglazed body may be glazed and fired. Preferred examples of the mixing ratio of the raw materials are as follows.

<Blending ratio (parts by weight)> Humidity controlling raw material such as Kanuma soil: 100 Clay: 100 to 1000 Vitreous component: 0 to 500 When sintering with a roller hearth kiln after glazing a molded product, the sintering temperature is 700. ~ 1000 ℃, especially 800 ~ 90
The temperature is preferably 0 ° C, and the time from entering the roller hearth kiln to exiting the roller hearth kiln is preferably 15 to 60 min, particularly preferably 20 to 30 min. When the molded body is unglazed after glazing and then further baked, the sintering temperature during unglaring is preferably 650 to 850 ° C, particularly preferably 700 to 800 ° C, and the time from entering the roller hearth kiln to exiting the roller heart kiln. Is 15-60 min, especially 20-3
0 min is preferred. In the case of glazing and firing after unglazing, the firing temperature during the glaze firing is preferably 750 to 950 ° C, particularly preferably 800 to 900 ° C, and the time from entering the roller hearth kiln to exiting the roller hearth kiln is as follows. 1
0 to 30 min, particularly preferably 15 to 20 min.

In any case, it is preferable that the higher the firing temperature, the shorter the firing time. Under such conditions, the humidity control plate material whose inside is darker than the surface layer is fired.

In the present invention, present within 80% or less of the dark portion said heat-when measured brightness distribution in the thickness direction of the cross section of the sintered body, on the most surface side lightness L _A relative lightness L _A The thickness of the dark portion is 20 times the thickness of the fired body.
It is preferably from 95 to 95%, especially from 25 to 90%, especially from 30 to 80%. Note that a particularly preferable range of the thickness of the dark-colored portion differs depending on the thickness of the fired body.

FIG. 1 is a schematic sectional view of this fired body, in which a dark-colored portion 2 is present in a layer inside a fired body 1.
Reference numeral 3 denotes a light-colored portion on the surface layer side. FIG. 2 is a graph schematically showing a brightness distribution in a thickness direction of a cross section of the fired body.

When the glazed humidity control plate material is fired by the firing method of the present invention, it is important that the original humidity control performance of the humidity control plate material itself is maintained high after firing, and preferably, the humidity control after glazing is performed. It is desired that the wet plate material has a humidity control performance of 80% or more of the humidity control plate material body before glazing. Further, the humidity control plate material of the present invention has a moisture absorption / release performance of 80 g / m ^{2 in} an 8-hour cycle.
It is preferable that it is above.

As described above, in order to perform glazing while maintaining high humidity control performance, it is important to control the glazed area and the glazed thickness. It is preferable to perform at least one of the conditions. Glazing may be performed by spraying, hanging, printing, etc., regardless of the method.

The area of the area of the glass layer generated by the glaze occupying the surface of the humidity control plate material body (hereinafter referred to as “glazing area ratio”) is 90% or less. The maximum thickness of the glass layer generated by the glaze (hereinafter,
Simply referred to as “maximum thickness”. ) Is 300 μm or less.

When the glaze area ratio exceeds 90%, the humidity control performance is remarkably reduced, and the humidity control performance as a humidity control plate material is impaired. However, if the glazed area ratio is less than 10%, the glazed surface is too small, and the effect of improving decoration and stain resistance cannot be sufficiently obtained. Therefore, it is preferable that the glaze area ratio is 10 to 90%, particularly 30 to 85%.

Incidentally, the glaze area ratio can be checked by an ink wiping test or the like, as described in the examples below.

As described above, when the glazing area ratio is 90% or less, the maximum thickness is not particularly limited, but is preferably 500 μm or less.

When the maximum thickness exceeds 300 μm,
If the glaze area ratio exceeds 90%, the humidity control performance is greatly reduced, so the maximum thickness is preferably 300 μm or less. However, if the maximum thickness is excessively thin, the effect of decoration by glaze and improvement of stain resistance cannot be sufficiently obtained. This maximum thickness is 10 to 100 μm when the glazing area ratio is 95 to 100%, and 20 to 2 when the glazing area ratio is 90 to 95%.
It is preferably set to 00 μm.

The reason that when the glass layer is made thinner as described above, the humidity control performance can be maintained high even when the entire surface of the humidity control plate material is glazed is that, when the thin glass layer is formed, defects in the base material or the firing process occur. It is supposed that fine holes permeable to water vapor penetrating to the humidity control plate material main body are likely to be formed in the glass layer due to the gas or the like.

In order to apply the above glaze area ratio and / or maximum thickness, the glaze method, the amount of glaze used for the glaze, the specific gravity of the glaze, and the like may be appropriately adjusted.

For example, the glaze area ratio can be suppressed to 90% or less by reducing the amount of glaze per unit area when performing glaze by a usual spray method or the like. Also,
Even in the case of full glaze by the curtain hanging method or the like, the maximum thickness can be reduced by reducing the amount of glaze per unit area.

In this glazing, a frit corresponding to the firing conditions is naturally required. However, in the case of rapid firing using a roller hearth kiln, the frit has a softening point which is lower than the firing temperature by one.
What is necessary is just to select what has low melt temperature of 00-400 degreeC, and moderate. If the viscosity is too low, the glass formed by the glaze fills the fine pores of the humidity control plate material body exhibiting the humidity control effect, and the humidity control performance is greatly impaired.

Therefore, in order not to impair the humidity control performance,
Adjust the amount of glaze and the melt viscosity of the glaze (softening point of frit) as appropriate.

In addition, there is also a method of adopting a decorative glaze method which can perform partial glaze such as spots, lines, and grids instead of the entire glaze. Since the glaze can be provided with a constant interval by the mesh, the glaze area ratio can be reduced. In addition, the centrifugal method has larger spots and glaze adheres than the other glaze methods, so the glaze area can also be reduced, which is effective for maintaining humidity control performance, and the patterning by glaze Thus, the design can be improved.

The glaze used for the glaze may be simply a slurry having a specific gravity of about 1.01 to 1.90 obtained by mixing a frit and water, and may further be mixed with clay or pigment. By incorporating the pigment, the design can be further enhanced.

[0038]

The present invention will be described more specifically below with reference to examples and comparative examples.

Examples 1 and 2 and Comparative Example 1 A molding material having the following composition was finely polished with a mill, spray granulated, and then press-molded using a press mold to produce a molded body.

<Materials for molding material (parts by weight)> Kanuma soil: 20 Clay: 60 Vitreous: 20 A slurry obtained by mixing an alkali aluminoborosilicate frit (softening point: about 570 ° C.) and water with the obtained molded body. (Specific gravity: 1.20 g / cm ³ ) was glazed with a spray gun at a rate of 100 g per unit area (1 m ² ), dried, and fired with a roller hearth kiln. Table 1 shows the firing conditions. The firing temperature in Table 1 indicates the maximum temperature in the kiln. The firing time indicates the time (min) from entering the roller hearth kiln to coming out.

For the obtained fired body, the glaze area ratio,
The maximum thickness, humidity control performance, moisture absorption / desorption performance in an 8-hour cycle, and the color of the surface layer and inside of the fired product were examined by the following methods.
It was 50 μm. Table 1 shows the measurement results of the humidity control performance and the moisture absorption / release performance in an 8-hour cycle, and the color of the surface layer and the inside of the fired product.

<Glazed Area Ratio> The ratio of the area where the ink was removed by applying an aqueous ink to the surface and wiping it with a cloth or the like soaked in water was determined by microscopic observation, image processing, or the like. <Maximum thickness> Determined by microscopic observation of the fractured surface. <Humidity control performance> Another constant temperature / humidity tank in which a test specimen whose weight was made constant (variation of 0.1% or less) in a constant temperature / humidity chamber maintained at a relative humidity of 50% was quickly maintained at a relative humidity of 90%. And put the weight increase (moisture absorption) after 8 hours in a unit area (1 m ² )
The weight gain of Example 1 was set to 100%, and the others were shown as relative values to Example 1.

<Moisture Absorption and Desorption Performance in 8-Hour Cycle> As described above, the amount of moisture absorption and desorption per 8 hours between the relative humidity of 50% and 90% is determined by converting it into a unit area (1 m ² ).

<Surface layer and internal color of fired product> The fired product is cut in the thickness direction and the color is observed.

Examples 3 and 4 and Comparative Example 2 In Example 1, an alkali silicic acid-based frit (softening point of 70) was used in place of the alkali-aluminoborosilicate-based frit.
0 ° C.) and the calcination conditions shown in Table 1 were used to obtain a baked body in the same manner.
When the humidity control performance and the moisture absorption / release performance in an 8-hour cycle were examined, the glaze area ratio was 80% and the maximum thickness was 150%.
μm. Table 1 shows the measurement results of the humidity control performance and the moisture absorption / release performance in an 8-hour cycle, and the color of the surface layer and the inside of the fired product.

[0046]

[Table 1]

[0047]

As is clear from the above Examples and Comparative Examples, by sintering so that the inside becomes darker than the surface layer, a humidity control plate material excellent in humidity control performance can be obtained.

[Brief description of the drawings]

FIG. 1 is a schematic sectional view of a humidity control plate manufactured by a method according to the present invention.

FIG. 2 is a schematic diagram showing a brightness distribution of a cross section of a humidity control plate material manufactured by the method according to the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Fired body 2 Dark color part 3 Light color part

 ────────────────────────────────────────────────── ─── Continued on the front page (72) Inventor Hiroshi Fukumizu 5-1-1 Koiehonmachi, Tokoname-shi, Aichi F-term in Inax Co., Ltd. (reference) 4G019 LA03 LB02 LB06 LD02

Claims (6)

[Claims] 1. A method of firing a plate-like molded product or a green body obtained from a raw material containing a humidity-controlling raw material, wherein the firing is performed so that the inside of the fired body has a darker color than the surface layer. The method of firing the wet plate material. 2. The lightness L _A on the most surface side when a lightness distribution in a thickness direction of a cross section of the fired body is measured.
_A dark-colored part having a brightness of 80% or less of LA is present inside the fired body, and the thickness of the dark-colored part is 20 to 95% of the thickness of the fired body. Firing method. 3. The method for firing a humidity control sheet material according to claim 1, wherein the raw material plate-like molded body is glazed and then fired. 4. The method for firing a humidity control plate material according to claim 1, wherein the unglazed body is glazed and fired. 5. The method for sintering a humidity control plate according to claim 3, wherein a glass layer formed by glaze is formed in an area of 90% or less of the surface of the humidity control building material body by sintering. 6. The method according to claim 3, wherein a maximum thickness of the glaze glass layer generated by the firing is 300 μm or less.