JPH0859333A - Production of ceramic base - Google Patents

Abstract

PURPOSE: To produce a ceramic base capable of suppressing firing deformation without deteriorating particularly strength at the time of firing. CONSTITUTION: A vitreous base having a composition, which is composed of 30-70wt.% glass phase and 70-30wt.% crystalline phase and contains mullite, quartz and α-alumina as the crystalline phase so as to be 15-70wt.% in the mullite, <=15wt.% in the quartz and <=15wt.% in the α-alumina based on the whole base as a reference, is obtained by adding powdery aluminum hydroxide or γ-alumina into a base main raw material prepared as a prescribed composition containing feldspars, clay and quartz before molding and 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 molten ceramic base material which constitutes a base material for sanitary ware.

[0002]

2. Description of the Related Art A sanitary ware base as a ceramic product used for sanitary facilities of a building such as a toilet bowl, a washbasin, a hand basin, a sink, and a cleaning sink has conventionally been made of a fusible base material. Here, the solute matrix is a matrix that is densified by forming a glass phase in the process of firing and filling the gaps between the matrix particles.

In the production of sanitary ware made of this fusible material, the molded product has conventionally been deformed in the firing process such as being distorted or dripping due to the formation of the glass phase, resulting in the shape and size of the product. It was a factor that deteriorated the accuracy.

It is possible to suppress the deformation of the molded product during the firing process by lowering the firing temperature in the firing step and softening the tightness of the base material. However, in this case, of course, the strength of the base material is weak and cannot be adopted as a practical method.

By the way, in the solute base material of sanitary ware, mullite (3Al ₂ O ₃ .2SiO ₂ ) produced by the reaction of the residual quartz and the constituents of the crystalline phase other than the glass phase during firing.
Etc. This mullite contains Al ₂
O ₃ and SiO ₂ react with each other to precipitate from the glass phase, and the larger the amount of mullite, the smaller the amount of the glass phase. In other words, the amount of the glass phase generated during firing is reduced, which acts to suppress the deformation of the molded product.

[0006] Conventionally, as a means for increasing the amount of mullite in the base material in terms of ceramics technology, a large amount of clay containing Al ₂ O ₃ which is a source of mullite is contained in the base material or alumina is added to the base material. When firing, Al ₂ O ₃ and SiO ₂
Although a method of reacting a large amount of and is known, it is necessary to raise the firing temperature in order to realize this, and it is difficult to adopt it as a practical method for producing a sanitary ware body that is an industrial product.

[0007]

The invention of the present application has been made in view of such circumstances, and it is an object of the invention to provide a method for producing a ceramic body which does not particularly lower the strength of the body and has a small deformation during firing. To aim. The invention of the present application for achieving the object is to add powdered aluminum hydroxide or γ-alumina to a base main raw material prepared to a predetermined composition containing feldspars, clays, and quartz, After firing, the base composition has a glass phase of 30 to 70% by weight and a crystal phase of 70.
˜30% by weight and mullite, quartz, α-alumina as a crystal phase, and mullite: 15 to 70% by weight, quartz: 15% by weight or less, α
-Alumina: It is characterized in that a solute matrix having a composition containing 15% by weight or less is obtained (Claim 1).

Another invention of the present application is characterized in that the powdery aluminum hydroxide having an average particle diameter of 1 to 50 μm is used (claim 2).

Still another invention of the present application is characterized in that the powdery aluminum hydroxide is added in an amount of 3 to 40% by weight based on 100 of the base main raw material (claim 3).

Still another invention of the present application is characterized in that the firing after the molding is performed at a temperature of 1150 to 1300 ° C. (claim 4).

Still another invention of the present application is characterized in that the ceramic base is a sanitaryware base (claim 5).

[0012]

As described above, according to the present invention, powdered aluminum hydroxide or γ-alumina is added to the base raw material containing feldspar, clay, and quartz, and the mixture is fired.

Here, as the raw material for the base material, there can be basically used the one which has been conventionally used as the raw material for the fusible base material. For example, as an example of the composition, a composition containing feldspar, silica stone, roeseki, limestone, frog-eyed clay, and kibushi clay, specifically, feldspar 14.2%, silica stone 29.5%, wax stone 23.9%,
Limestone 3.8%, Frog Eye Clay 23.9%, Kibushi Clay 4.7
A composition consisting of% can be exemplified. Or feldspar 1
7.2%, silica stone 21.8%, pottery stone 23.0%, rouxite 1
An example is a composition consisting of 9.8%, limestone 1.6%, and gairome clay 16.6%. Of course, other compositions may be used.

Further, as the chemical components, those composed of the following components can be used. _{SiO 2 65~75 Al 2 O 3 18~25} Fe 2 O 3 0.5~1.5 MgO 0.3~1.0 CaO 1.0~2.5 K 2 O 2.5~3.5 Na ₂ O 1.0-1.5 Burning loss 0-0.5

It has been confirmed that when powdered aluminum hydroxide or γ-alumina is added to the main raw material of the base material and fired according to the present invention, the deformation can be favorably suppressed in the firing process without particularly lowering the strength of the base material. There is. This is considered to be due to the following reasons.

As for the case where aluminum hydroxide is added to the base material, the aluminum hydroxide is decomposed into Al ₂ O ₃ and H ₂ O by heating in the firing process. The Al ₂ O ₃ produced at this time is rich in activity (reactivity), and the Al ₂ O ₃ produced therein reacts well with the SiO ₂ content contained in the main raw material of the base material to give mullite (3Al ₂
It is considered to generate O ₃ · 2SiO ₂ ).

It is considered that the production of a large amount of mullite causes the base material to be densified and the amount of the glass phase to decrease, which acts to suppress the deformation of the base material during the firing process. .

According to the present invention, the maximum amount of mullite is 7
It is possible to generate up to 0%. In other words, by setting the amount of mullite in the base material to be 15 to 70% by weight, it is possible to favorably suppress the deformation of the base material during the firing process.

The reactivity of the added aluminum hydroxide varies depending on its particle size and the amount added. FIG. 1 schematically shows this. In FIG. 1, M indicates a mullite crystal in the matrix. When aluminum hydroxide having a small particle size is added, most of it reacts with SiO ₂ and is converted into mullite in the firing process because of its higher reactivity, and the mullite crystal M is dense and dense in the matrix. It crystallizes in the case of ((a)).

On the other hand, when aluminum hydroxide having a large particle size is used, Al ₂ O ₃ particles A produced by decomposition remain unreacted and mullite crystals M are densely crystallized around them (( )in the case of). In any of these patterns, the thermal deformation of the substrate is suppressed, and the Al ₂ O ₃ particles A remaining in the substrate in an unreacted state act to maintain the strength of the substrate high by dispersion strengthening.

As described above, the amount of mullite formed in the base material changes depending on the particle size or the amount of aluminum hydroxide added, but in the present invention, mullite formed in suppressing thermal deformation of the base material. Amount of 25
It is more desirable to set it to -60%. Even when γ-alumina is added, the deformation, suppressing action and strengthening action of the substrate are basically the same as above.

Γ-Alumina is a very fine crystal and has a solid crystal structure and is rich in activity. Even when such γ-alumina is added, this γ-alumina is added. Reacts well with SiO ₂ during firing to form mullite.

In the present invention, the glass phase is 30 to 70%,
The reason why the crystal phase is set to 70 to 30% is that the structure is necessary to obtain a dense solute matrix, and quartz and α-
The reason why alumina is set to 15% by weight or less is as follows. That is, when the content of quartz is more than 15%, the strength of the base material is lowered, and the reason why the content of α-alumina is 15% or less is that the reaction amount of alumina is smaller and the formation of mullite is smaller when the content is more than this. It depends.

In the present invention, when powdered aluminum hydroxide is added, the average particle size is 1 to 50 μm.
It is desirable to use m. If it is 1 μm or less, the particles are too fine to disperse the particles well,
On the other hand, if a material having a thickness of less than 50 μm is used, the reactivity is lowered and it is difficult to achieve the object of the present invention. A more desirable particle size range is 1 to 20 μm.

On the other hand, the amount of addition is 100
It is desirable to be 3-40%. Addition amount is 4
If it is more than 0%, the strength will be lower than the desired level (50 MPa). On the other hand, if the added amount is less than 3%, it is difficult to achieve the object of the present invention. The more desirable range of addition is 3 to 20%.

As described above, even when α-alumina is added to the base material, the firing temperature is 1400 ° C.
At the above predetermined high temperature, it is possible to react α-alumina with SiO ₂ to generate mullite. However, it is difficult to practically employ such high temperature firing.

According to the present invention, however, mullite can be effectively produced even when fired at a temperature lower than 1300 ° C. which is the firing temperature of conventional ordinary sanitary ware (claim 4). On the other hand, even if the material is fired at a temperature lower than 1150 ° C., it is possible to suppress the generation of the glass phase in the firing process and suppress the thermal deformation of the base material. As a result, the strength of the base material is remarkably low.

However, in the present invention, even when firing is performed at a temperature of 1150 ° C. or higher, the deformation during firing can be effectively suppressed and the structure can be densified.

As is clear from the above description, the present invention has a great effect when applied to the production of sanitary ware (Claim 5). In this case, sludge casting can be adopted as the molding method, in which, when adding aluminum hydroxide or γ-alumina to the sludge, a predetermined peptizer or an organic binder for increasing the strength of the molding base is used. And the like can be used together.

[0030]

EXAMPLES Examples of the present invention will be described in detail below.・ Fukayama feldspar 15% ・ Seto quartz sand 28% ・ Gypsum stone 24% ・ Shimizu lime 4% ・ Masui frog eyes 24% ・ Honyama Kibushi 5% Composition containing 25% water (outer ratio) Was prepared in advance, and the average particle size of this slurry was 1-80.
Powdered aluminum hydroxide having various particle sizes in the range of μm was added and mixed and dispersed. At this time, a deflocculant composed of ammonium polycarboxylic acid and an organic binder composed of an acrylic emulsion were added together and mixed. The preferable amount of the deflocculant is 0.1 to 1.0% with respect to 100 of the slurry, and the preferable amount of the organic binder is 0.1 to 0.1%.
0.8%.

Next, this was subjected to 45 × 100 × 7 according to a conventional method.
The sample 10 was formed into a plate-shaped compact of mm, and was supported between the projections 12a of the support 12 as shown in FIG. 4, and was fired under the firing condition of 1250 ° C. × 1 hr. The indenter displacement of the obtained fired product was measured by the load softening test method (see FIG. 4). The results are shown in Tables 1 to 3.

[0032]

[Table 1]

[0033]

[Table 2]

[0034]

[Table 3]

In order to determine the influence of the amount of aluminum hydroxide added and the particle size, the relationship is obtained by taking the amount of addition or particle size on the horizontal axis and the amount of deformation or strength on the vertical axis, and FIG. It is represented in FIG. From these results, particle size 1-5
A good result was obtained by adding 0 μm of aluminum hydroxide in an amount of 3 to 40% (deformation amount of 6 mm or less, strength of 50 MP).
a or more, mullite amount of 21% or more) is obtained, and especially the particle size is 1
It can be seen that even better results were obtained when aluminum hydroxide having a thickness of -20 μm was added in the range of 3 to 20%.

The embodiment of the present invention has been described in detail above, but this is merely an example, and the present invention can be implemented in variously modified modes without departing from the spirit of the invention.

[Brief description of drawings]

FIG. 1 is a diagram schematically showing the principle of the present invention.

FIG. 2 is a diagram showing the relationship between the particle size or addition amount of aluminum hydroxide and the deformation amount of a fired product obtained in Examples of the present invention.

FIG. 3 is a diagram showing the relationship between the grain size or the amount added and the strength of the fired product obtained in the examples of the present invention.

FIG. 4 is an explanatory diagram of a test method for confirming the effect of the example of the present invention.

[Explanation of symbols]

 10 Specimen 12 Support

Claims (5)

[Claims] 1. A powdery aluminum hydroxide or γ-alumina is added to a base main material prepared to have a predetermined composition containing feldspars, clays and quartz, and the mixture is molded and fired, and the base composition has a glass phase of 30 to 30. 70% by weight, 70 to 30% by weight of crystalline phase, and mullite, quartz, α-alumina as crystalline phase, and mullite: 15 based on the whole substrate
˜70 wt%, quartz: 15 wt% or less, α-alumina:
A method for producing a ceramic body, which comprises obtaining a solute base material having a composition containing 15% by weight or less. 2. The method for producing a ceramic body according to claim 1, wherein the powdery aluminum hydroxide having an average particle size of 1 to 50 μm is used. 3. A method for producing a ceramic body, wherein the powdery aluminum hydroxide is added in an amount of 3 to 40% by weight based on 100 of the base main raw material. 4. 1150 to 1300 firing after the molding
The method for producing a ceramic body according to claim 1, wherein the method is performed at a temperature of ℃. 5. The method for producing a ceramic body according to claim 1, 2, 3, or 4, wherein the ceramic body is a sanitaryware base.