JPH06144923A - Production of ceramic product - Google Patents

Abstract

PURPOSE:To improve the aptitude for extrustion molding and to reduce the contraction in firing in the production of a ceramic product. CONSTITUTION:A cement mixture with cement, inorg. powder, quartz sand, a thickener and water as the essential components is extrusion-molded, hydration-cured and then fired to produce a ceramic product. The inorg. material contains >=30% vitreous materials, the quartz sand content is controlled to 15-55wt.% of the entire cement mixture, the cement mixture is extrusion-molded and hydration-cured, a glaze material is applied on the surface, and the molded product is fired. Otherwise, the cement mixture is extrusion-molded, rouggednesses are formed on the surface before or after hydration curing, and then the molded product is fired. Alternatively, the cement mixture is extrusion- molded, rouggednesses are formed on the surface before or after hydration curing, then the glaze raw material is applied on the surface, and the molded product is fired. Consequently, a ceramic product is obtained with the contraction reduced in firing.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a ceramic product used for interior and exterior finishing, and to a product having improved dimensional accuracy and productivity.

[0002]

2. Description of the Related Art The applicant of Japanese Patent Application No. 2-199970 (Japanese Unexamined Patent Publication No. 4-89352) molded a mixed composition of cement and glass and prepared a ceramic material using hydration hardening and firing of glass material. The manufacturing method was proposed.

This is because a cement mixture containing cement, inorganic powder containing 50% or more of glass, soft glass crushed powder, a thickener, and water is extruded, hydrated, and fired. It is a thing.

[0004]

In the prior art, although shrinkage due to firing was improved as compared with the conventional one, there was room for further improvement by showing a shrinkage of 1 to 4% in the experiment.

[0005]

The present invention has been made in view of the above problems, and increases the amount of silica sand added as an auxiliary material of 6 to 12% in Examples in the prior art. This not only improves the shrinkage during firing, but also improves extrusion molding suitability without the need for crushed glass, which was an essential component in the prior art, and broadens the range of application of inorganic powder. Became possible.

In the method for producing a ceramic product of the present invention, in claim 1, a cement mixture containing cement, inorganic powder, silica sand, a thickener and water as essential components is extruded and hydrated and hardened. In the method of manufacturing a ceramic product obtained by firing,
According to claim 2, wherein the inorganic powder contains 30% or more of vitreous material, and the content of the silica sand is 15 to 55% by weight of the mixture. After that, the glaze raw material is applied to the surface and fired. According to claim 3, the cement mixture is extruded and molded, and after unevenness is formed on the surface before or after hydration curing,
In claim 4, the cement mixture is extruded and formed, and after the unevenness is formed on the surface before or after the hydration curing, the glaze raw material is applied to the surface and baked. According to a fifth aspect of the present invention, in the second and the fourth aspects, glazing is applied as a technical means before the glaze material is applied to the surface.

[0007]

With the above construction, silica sand improves the slipperiness with the mold during extrusion molding, and the extrusion pressure is reduced to improve the productivity. The presence of silica improves the density of the extrudate, reduces drying shrinkage, and reduces the glass content to 30%.
%, Even if inorganic powder of about
Hard to crack.

According to the second aspect, since the shrinkage during firing is small, the glaze raw material is glazed and fired for good adhesion.

According to the third aspect, since the density of the extruded product is improved, it is possible to carry out the firing while maintaining the textured shape.

According to the fourth aspect of the present invention, since the density of the extruded product is improved, it is possible to perform firing while maintaining the textured shape, and the shrinkage due to firing after glaze is small, so that the adhesion is good. In the fifth aspect, since the glazing raw material is unglazed before being applied to the surface, the organic component in the cement mixture is burned, and a certain amount of vitreous fusion is caused, so that gas generation and shrinkage are reduced, and the glaze is Pinholes and chips are unlikely to occur.

[0011]

Embodiments of the present invention will be described below.

The cement used in the present invention is Portland cement, alumina cement, fly ash cement or the like, which is 20 to 70% by weight of the whole mixture.

Cement not only enhances transportability and workability before firing, but also suppresses shrinkage during firing.
If the ratio is less than 20% by weight, the hydration hardening is insufficient, and 7
If it exceeds 0% by weight, the amount of the inorganic powder to be described later is relatively reduced and the strength after firing is reduced, which is not preferable.

Inorganic powder containing 30% or more of glassy material means natural minerals and inorganic wastes such as shirasu, minestone,
The content of fly ash, slag, etc. is 25 to 75% by weight of the whole mixture, and a single substance or a mixture thereof is used.

The above-mentioned inorganic powder contributes to the development of strength by fusing when fired at 1000 ° C. or higher, but if the mixing ratio is less than 25%, the firing strength is insufficient, and if it exceeds 75%, the cement becomes cemented. Since it decreases relatively, the strength at the time of hydration hardening becomes insufficient.

Although it is possible to use an inorganic material having a glassy content of less than 30% such as silica, kaolin and talc as a filler, it is not an essential component because it is difficult to cause fusion during firing. .

Among crushed alkaline glass powders such as plate glass and glass bottles, those having a particle size of 500 μ-under, preferably 50 μ-under are mixed with 0 to 40% by weight of the above-mentioned inorganic powder, and gently calcined from a low temperature. It is effective in causing adhesion and preventing defects such as cracks, but it is not an essential component.

Silica sand is a solid powder rich in SiO _2.
Mixing in the range of 5 to 55% by weight improves the extrudability of the cement mixture and contributes to increasing the density of the molded body.

It is preferable that the average particle size is 100 μm or more, which is slightly larger than the cement powder and has a wide particle size distribution.

That is, since silica sand exhibits slipperiness between the cement mixture and the inner surface of the mold during extrusion, the cement mixture, which has been difficult to slip in the mold with a low water content, can be easily extruded. The smaller the amount, the higher the density of the molded body, which contributes to the development of strength and dimensional stability.

If the content of silica sand is less than 15% by weight, clogging occurs in the mold unless the mixing ratio of water is increased or other materials such as crushed glass for improving extrusion suitability are added, while 55 If it exceeds 5% by weight, the mixing ratio of cement and the inorganic powder is relatively decreased, and the hydration hardening strength and the firing strength are decreased, which is not preferable.

The thickening agent is for improving plasticity and shape retention, and is methyl cellulose, carboxymethyl cellulose, PVA or the like, and is added in an amount of 0.2 to 2% by weight based on the whole mixture.

The water is 15 to 2 with respect to the weight of the whole mixture.
5% by weight is added. If it is less than 15% by weight, extrusion cannot be performed, and if it exceeds 25% by weight, the shape retention after molding is deteriorated, and excessive moisture is evaporated during firing to form gaps and shrinkage or cracks.

The above mixture may be mixed with reinforcing fibers such as wollastonite or steel fiber, or as aggregates such as chamotte, river sand, kaolinite, serpentine and talc.

The above mixture is added, for example, at a pressure of 20 to 70 kg.
/ Cm ² , the degree of vacuum is about 1 to 20 cmHg, and the mixture is extruded and cured for several hours to several days to cause a hydration reaction.

As a result, the molded plate is hardened to such an extent that it does not hinder the transfer and deposition, and has an internal fine structure in which glassy fusion is likely to occur during firing.

Then, it is put in a firing furnace and the maximum temperature is set to 100.
0 ° C. or higher, preferably 10 at 1000 to 1300 ° C.
It is obtained by firing for several minutes to several hours. Before and after the firing, a temperature rising and cooling step is appropriately performed.

At this time, slaked lime generated by hydration of cement becomes quick lime during firing and absorbs moisture to expand and causes strength deterioration. To prevent this, to react lime and glassy matter. In addition, the firing temperature must be 1000 ° C or higher.

1% of ceramic products manufactured by the above method
The shrinkage ratio is as follows, and the dimensional stability is far superior to that of a ceramic product which has been conventionally regarded as a shrinkage of 10 to 15%, which is an improvement over the prior art.

In the second aspect, after the above-mentioned hydration curing, the glaze raw material is applied by spraying or the like and then baked. Since the above-mentioned glaze raw material is fired at 1000 ° C. or higher, it is possible to adopt a tile or the like that is widely used in conventional ceramic products, and it is possible to create makeup that is rich in variations such as gloss and blurring patterns. Further, as described above, since the shrinkage due to the firing of the base material is small, the adhesion of the glaze is good, cracks hardly occur, and the gloss, surface hardness and stain resistance are good.

According to the third aspect, after extrusion molding, before hydration hardening, the surface is subjected to uneven processing such as embossing or cutting, or after hydration hardening is cut to form grooves or the like and fired. It will be. Specifically, a mold roll or a mold belt is provided near the mouth of the extrusion molding machine to imprint a pattern on the surface of the extruded uncured plate-like material, or a pattern is printed on a feed conveyor to make a router or a surface. Cut with a cutter, etc., and make up makeup joints such as lattices and stripes. According to the configuration of the present application, since shape retention after unevenness processing and shrinkage during firing are small, mold reproducibility and linearity are likely to occur.

In the fourth aspect, after extrusion molding, the surface is subjected to uneven processing such as embossing or cutting before hydration hardening, or it is cut after hydration hardening, and the glaze raw material is applied and baked before baking.
As a result, a three-dimensional appearance can be formed, and it is possible to obtain a tile panel-like long plate having a large number of pseudo joints and a plate having an irregular cross section.

In the fifth aspect, unglazing is performed before coating the glaze material. That is, after extrusion molding, as shown in claim 4, the surface is embossed or cut before hydration hardening, or after hydration hardening, it is cut and roughened, and then the glaze raw material is applied. A method and an improvement of the method of applying a glaze raw material after hydration hardening without applying unevenness processing, as described in claim 2, in which an organic component such as a thickener or impurities is applied before the glaze raw material is applied. The material is burned and heated at 600 ° C. or higher for several minutes to several hours in order to promote fusion of glassy material. You may bisque at the same temperature as.

After the above-mentioned unglazed step, the glaze raw material is applied and baked in the heated state or after cooling once. As a result, the generation of pinholes and cracks due to the release of internal combustion gas can be prevented, and the firing shrinkage can be alleviated, so that the glaze can be prevented from peeling or chipping.

[0035]

[Experimental Examples] Examples will be described below. Example 1 Cement 29, minestone 32, silica sand 20, methylcellulose 1, and 17% by weight of water are mixed, and a plate having a width of 300 mm, a thickness of 18 mm, and a length of 450 mm is formed in the longitudinal direction of the material by a vacuum extrusion molding machine. Then, after being left indoors for 2 days, it was cured at 80 ° C. for 8 hours and then baked at a maximum temperature of 1180 ° C. for 1 hour to obtain a ceramic plate.

The above mixture had good shape retention during extrusion molding, was transportable after hydration curing, had a drying shrinkage of 0.8% upon firing, and was free from warpage and cracks. The bending strength of the plate after firing is 210 kg / cm on average
^In No. ² , it was found that the material has sufficient strength as an interior / exterior finishing material.

Example 2 Cement 25, Shirasu 25, soft glass crushed powder 4, silica sand 2
9, methylcellulose 1 and 16% by weight of water were mixed, the plate was extruded and molded in the same manner as in Example 1 above, and after curing, glaze was spray-coated and baked at a maximum temperature of 1170 ° C. for 30 minutes to obtain a ceramic plate. Obtained. The shrinkage ratio of this Example 2 is 0.3.
%, No crack was observed on the glazed surface.

The bending strength of the plate after firing is 205 kg / average.
It was cm ² . Example 3 Cement 33, slag 17, soft glass crushed powder 8, silica sand 2
5, methyl cellulose 1 and 16% by weight of water were mixed, the plate was extruded and cured in the same manner as in Example 1 above, and after curing, a lattice-shaped groove was cut with a router at 10 cm intervals, and the maximum temperature was 1170 degrees. It was fired at C for 1 hour to obtain a ceramic plate.

It was found that in Example 3 obtained in this way, the grid-like straight lines were formed with high precision, and that it was also suitable for surface processing. Further, the shrinkage ratio of this Example 3 is 0.3.
%, No cracks were observed. Example 4 In Example 1, after hydration hardening, after cutting according to Example 3, the glaze raw material according to Example 2 was spray-coated and fired to obtain a ceramic plate. Example 4 obtained by adding
Has a glossy tile panel-like appearance,
It was found that the surface can be formed accurately. As described above, in this experiment, it was found that a ceramic product having a small shrinkage and a good surface property can be obtained.

Example 5 A plate having the same composition as in Example 2 was extruded in accordance with Example 1 and cured, and then cured at a maximum temperature of 1170 ° C. for 15 minutes.
Do unglazed for a minute, then spray-apply glaze,
It was baked at a maximum temperature of 1170 ° C for 15 minutes to obtain a ceramic plate. In Example 5, the shrinkage rate was 0.2%, and no pinholes or cracks were observed on the glazed surface, and a glossy surface was obtained. The bending strength of the plate after firing is 205 kg / cm ^{2 on} average
Met.

[0041]

As described above, according to the present invention, silica sand in the composition improves the slipperiness with the mold during extrusion molding and reduces the extrusion pressure to improve the productivity. Is possible.

Silica sand improves the density of the extruded product, reduces the drying shrinkage, and develops the glassy fusion strength by firing, which makes it difficult for cracks to occur and to provide a building finish with good surface properties. You can

According to the second aspect, since the shrinkage during firing is small, the adhesion is improved when the glaze raw material is glazed and fired,
You can get a decorative plate whose surface is hard to peel off.

According to the third aspect, since the density of the extruded product is improved, it is possible to carry out firing while maintaining the uneven shape, so that a sharp three-dimensional appearance can be obtained.

According to the fourth aspect, the density of the extruded product is improved, the textured shape is maintained, and the shrinkage due to firing after glaze is small, so that the three-dimensional effect is good and the adhesion of the glaze is good. Is obtained.

In the fifth aspect, since the glaze material is bisqued before being applied to the surface, the organic component in the cement mixture is burned and a certain amount of vitreous material is fused, so that gas generation and shrinkage are small. It is possible to obtain a decorative plate that is highly glossy and is unlikely to cause pinholes or chips in the glaze.

Continuation of the front page (51) Int.Cl. ⁵ Identification code Office reference number FI technical display location C04B 41/00

Claims (5)

[Claims] 1. A method for producing a ceramic product, which comprises extruding a cement mixture containing cement, inorganic powder, silica sand, a thickener and water as essential components, extruding, hydrating and curing, followed by firing. The inorganic powder contains 30% or more of glass, and the silica content is 15 to 55% by weight of the mixture.
A method of manufacturing a ceramic product, comprising: 2. A ceramics obtained by extrusion-molding a cement mixture containing cement, inorganic powder, silica sand, a thickener and water as essential components, hydration curing, and then applying a glaze raw material on the surface and firing. A method for producing a ceramic product, wherein the inorganic powder contains glass of 30% or more, and the silica content is 15 to 55% by weight of the mixture. 3. A cement mixture comprising cement, inorganic powder, silica sand, a thickener and water as essential components is extruded to form irregularities on the surface before or after hydration curing,
In the method for producing a ceramic product by firing, the inorganic powder contains glass of 30% or more, and the silica content is 15 to 55% by weight of the mixture. Manufacturing method. 4. A cement mixture comprising cement, inorganic powder, silica sand, a thickener and water as essential components is extruded to form irregularities on the surface before or after hydration curing,
In a method for producing a ceramic product by applying a glaze raw material on the surface and firing, the inorganic powder contains 30% or more of glass, and the silica content is 15 to 5% of the mixture.
A method for producing a ceramic product, which comprises 5% by weight. 5. A cement mixture containing cement, inorganic powder, silica sand, a thickener and water as essential components is extruded to form irregularities on the surface before or after hydration curing,
Alternatively, in a method for producing a ceramic product, which is obtained by applying glazing raw material on the surface after firing without forming a concavo-convex portion, and the inorganic powder contains 30% or more of glassy material, and the content of silica sand is included. 15-55% by weight of the above mixture
A method of manufacturing a ceramic product, comprising: