JPH08143380A - Expanded ceramic molded plate - Google Patents

Abstract

PURPOSE: To obtain a lightweight expanded ceramic molded plate having large strength, permeable to air, impermeable to water and having improved water absorbing property and heat insulating property by firing a compsn. consisting of fine hollow ceramic particles and an aq. soln. of an alkali silicate after kneading and press molding. CONSTITUTION: Fine hollow ceramic particles having >=600kgf/cm<2> compressive strength, 0.3-0.5g/cm<3> bulk density, >=1,500 deg.C m.p. and about 0.1kcal/m.hr. deg.C heat conductivity are added by 100-300 pts.wt. to 10-300 pts.wt. 10-60% aq. soln. of an alkali silicate represented by the general formula M2 O.mSiO2 .nH2 O (where M is an alkali metal or a quat. ammonium salt and (n)<=8) and they are well kneaded under 400kgf/cm<2> stress and shear. A slurried inorg. coloring pigment is sprayed at need, a dispersant is added and the resultant stock is charged into a mold and press-molded to form an expanded ceramic molded plate having 0.5-0.7g/cm<3> specific gravity. The molded plate is fired at 700-1,300 deg.C for about 30min to obtain the objective expanded ceramic molded plate in which capillary-shaped fine air circulating holes exist.

Description

Detailed Description of the Invention

[0001]

INDUSTRIAL APPLICABILITY The present invention is used for building and civil engineering members such as outer wall materials, floor materials, ceiling materials, roof tiles, sound absorbing materials, and water-permeable pavement materials used for buildings, and other filters and air diffusers. The present invention relates to a foamed ceramic molded plate.

[0002]

2. Description of the Related Art Conventionally, there have been the following foamed ceramic molded plates or porous ceramic molded plates. That is, a mixture of natural minerals such as porcelain stone, feldspar and clay, or a mixture of oxide-based ceramic powder with a binder added to an inorganic or organic foaming agent, kneaded and molded, and then fired at a high temperature of 1000 ° C or higher. Are known.

Further, a porosifying agent or a foaming agent is added to a slurry containing ceramic powder and a binder, and the slurry is molded and fired. Furthermore, ceramic porous molded plates in which inorganic fine foams and ceramic fragments are bound by a binder are also widely used.

However, in the case of using natural minerals such as porcelain stone, feldspar, and clay as raw materials, good quality materials are gradually decreasing, and it is difficult to obtain them. Further, in the method using the porosifying agent, a large amount of the porosifying agent must be used in order to produce a foamed ceramic molded plate having a high porosity and a high pore size, and the porosifying agent is dispersed in the slurry and scattered during firing. However, it is difficult to stabilize the quality because it damages the foam ceramic molded plate.

In the method using a foaming agent, it is difficult to form regular fine inside cavities as designed. Inorganic microfoam or ceramic shards that are bound by a binder have irregular shapes such as inorganic microfoam or ceramic shards, and their surface is not smooth, resulting in large binder absorption and poor quality stability. It does not result in a good quality foam ceramic molded plate.

As described above, the conventional foamed ceramic molded plate or porous ceramic molded plate is one having fine voids inside the ceramic molded plate, or one in which the periphery of the fine foamed body is simply solidified with a binder or the like. there were. For this reason, in the foamed ceramic molded plate, air cannot penetrate, or in the case of a diffuser plate or one intended for a filter, conversely, there are only large air flow holes, and therefore the heat insulation is low and fire resistance is low. He had no resistance.

[0007]

DISCLOSURE OF THE INVENTION The present invention solves the problems of the conventional foamed ceramic molded plate as described above, is lightweight and has strength, and is a microcapillary air in the micron unit through which air flows. By having a flow hole, it is possible to provide an excellent foamed ceramic molded plate that allows air to penetrate but does not penetrate water, has extremely high water absorption performance, is excellent in heat insulation performance, and has extremely low backside temperature rise against flame. To aim.

[0008]

[Means for Solving the Problems] The above-mentioned problem is that the foamed ceramic molded plate is composed of innumerable perfectly spherical fine hollow particles,
By connecting the fine hollow particles to each other at points, it is possible to have micron-sized capillary air flow holes between the fine hollow particles.

According to the present invention, since a large number of micron-sized capillary air circulation holes are retained in the foamed ceramic molded plate, high-strength ceramic fine hollow particles are spot-bonded with an alkali silicate.

That is, from 100 to 300 parts by weight of fine ceramic hollow particles having a compressive strength of 600 kgf / cm ² or more, a bulk specific gravity of 0.3 to 0.5 g / cm ³ , and a melting point of 1500 ° C. or more and 10 to 300 parts by weight of an aqueous alkali silicate solution. 10 to 200 kgf / cm ² by kneading the composition
It is characterized in that it is molded at a pressure of 1, is cured to a hardness that can be handled, is then demolded, and the molded body is baked at a low temperature of 700 to 1300 ° C.

The colored expanded ceramic molded product can be made into a colored expanded ceramic molded plate by spraying the slurry-like colored inorganic pigment in advance on the ceramic fine hollow particles and using the dried colored ceramic fine hollow particles. .

[0012]

The ceramic fine hollow particles used in the present invention have particularly high compressive strength as compared with conventional fine hollow foams, and can withstand high stress and shearing force generated in the process of producing foamed ceramic molded bodies. Is what you can get. Further, by pressure molding, it is possible to obtain a dense foam ceramic molded plate despite its light weight.

The compressive strength of the fine hollow foam is synonymous with the hydrostatic strength, and the compressive strength is measured by pressurizing the fine hollow foam in water and transmitting the pressure applied to the water to the fine hollow foam. The pressure at which the hollow foam breaks is the compressive strength.

A foamed ceramic molded plate capable of exhibiting excellent performance must have a sufficient kneading process, and is particularly important for a foamed ceramic molded plate of a uniform product and of good quality. When performing sufficient kneading, the stress and shearing force applied to the ceramic fine hollow particles during the kneading are about 400 k.
It is said to be around gf / cm ² . Since no conventional fine hollow foam can withstand such a high pressure, none of them can be used as such a foam ceramic molded plate and have sufficient performance. That is, most of them will be destroyed.

Next, when the ceramic fine hollow particles are used in the foamed ceramic molded plate, the important factor is the thermal conductivity. Depending on the particle size of the fine hollow foam, it is generally 0.1 (kc
Al / mhr ° C.), and when half of the filled fine hollow foam is broken, the thermal conductivity is about 0.
2 (kcal / mhr ° C.). The excellent effect is obtained only when a perfectly fine hollow foam which is not broken is used. The ceramic fine hollow particles used in the present invention have significantly higher compressive strength than conventional fine hollow foams such as shirasu balloon, glass balloon, silica balloon, fly ash balloon, and the like. The hollow body is 100% complete. The compressive strength of the conventional fine hollow foam is 80 to 3
It is 00 kgf / cm ² .

The melting point of the ceramic fine hollow particles used in the present invention is 1500 ° C. or higher. Naturally, the fine ceramic hollow particles are caused by their material, but generally, the higher the melting point, the higher the compressive strength. Compressive strength 600
If it is more than kgf / cm ^2, its melting point is 1500 ° C.
You have to do more than that.

The foamed ceramic molded plate is formed by pouring the slurry into a mold, curing it for a predetermined time, and then firing it. The firing temperature is 700 to 1300 ° C., which depends on the melting point depending on the type of alkali silicic acid used. The ceramic fine hollow particles are joined at points to firmly bond them. The silicate used as a binder is melted and the ceramic fine hollow particles are fixed by this melt. However, the ceramic fine hollow particles should not be melted during firing, and the strength should not be reduced by heating. Therefore, the melting point of ceramic fine hollow particles is 1
It must be above 500 ° C.

As described above, the fine ceramic hollow particles used in the present invention are obtained by foaming a composition composed of 40% alumina and 60% silica, and the physical properties are as follows: compressive strength 700 kgf / cm ² , melting point 1600 ° C., bulk specific gravity 0. 0.3-0.5 g / cm ³ , thermal conductivity 0.1 (kcal
/ Mhr ° C.) and is composed entirely of hollow particles.
The fine ceramic hollow particles have a position diameter in the range of 20 to 350 μm, fine 20 to 75 μm, medium 75 to
The particle size is adjusted to 150 μm and the roughness is 150 to 350 μm, and mixed and used. Bulk specific gravity is heavy for fine particles,
Rough things get lighter. Therefore, the range of bulk specific gravity is 0.3 to
It becomes 0.5 g / cm ³ .

The alkali silicate aqueous solution used in the present invention forms an excellent and strong glassy film, and the general formula is M
Represented by ₂ O · mSiO ₂ · nH ₂ O, the alkali metal M includes sodium, potassium, lithium and the like, and there is a quaternary ammonium salt as a special one. n is 8
The following is shown, and the concentration of the aqueous solution is preferably in the range of 10 to 60%.

Ceramic fine hollow particles include fine, medium,
After adjusting the grain size of the coarse grain, 10 to 300 parts by weight of the aqueous alkali silicate solution is added to 100 to 300 parts by weight. When the amount of the alkali silicate aqueous solution is 10 parts by weight or less, sufficient kneading cannot be performed and the bonding strength between the ceramic fine hollow particles cannot be increased.
On the other hand, when the amount is 300 parts by weight or more, the amount of the melt in the foam ceramic molded plate is too large to form the capillary air flow holes.

The foamed ceramic molded plate is extremely lightweight because the ceramic fine hollows having high strength are bonded to each other and this portion is fixed by the welded material of alkali silicate, and the specific gravity of the foamed ceramic molded plate is 0.5 to 0.7 (g / cm
³ ) Further, since the pressure is applied at 10 to 200 kgf / cm ² at the time of molding, the foamed ceramic molded plate becomes dense and has high strength, and the compression strength is 100 kgf / cm ² or more.

The ceramic fine hollow particles having high strength are
Since it can be completely present in the form of a hollow body in the foamed ceramic molded plate, there are numerous capillary air circulation holes in the part other than the point-bonding due to the point-bonding between the ceramic fine hollow particles. I found that.

Only 1 (kg / cm ² ) is possible due to the innumerable mesh-like capillary air circulation holes.
Even at a low air pressure, air flows from the surface of the foam ceramic molded plate. That is, the air from the surface flows not only to the back surface of the foam ceramic molded plate but also to the four circumferences of the foam ceramic plate. Particularly in the case of high-heat air, most of it flows upward from the surface and diffuses from the upper end of the foam ceramic molded plate.

Therefore, even if a flame is applied to the surface of the foam ceramic plate according to the present invention, high-heat air due to the flame flows evenly over the foam ceramic molded plate. Therefore, the rise of the back surface temperature is small and the whole foam ceramic molded plate acts as a heat dissipation plate.

When the foamed ceramic molded plate is placed horizontally and water is dripped on the surface thereof, the dripped water can be immediately absorbed. That is, the water dripped into the capillary-shaped air circulation holes which are stretched like a mesh in the foam ceramic molded plate immediately flows and is absorbed. The absorbed water does not immediately penetrate the back surface because it flows horizontally and gradually flows downward. Water flows into the capillary air flow holes of the foam ceramic molded plate, and the amount of water absorption is almost the same as the weight of the foam ceramic molded plate.

The foamed ceramic molded plate of the present invention has a compressive strength of 600 kgf / cm ² or more and a bulk specific gravity of 0.3 to.
0.5 g / cm ³ , fine ceramic hollow particles with a melting point of 1500 ° C or higher and an aqueous solution of alkali silicate are the main constituents, but various surfactants, antibacterial agents, antibacterial agents and antibacterial agents are used as necessary to improve the properties. An admixture such as a fungicide, an antifreezing agent, a stabilizer, or an inorganic extender pigment may be used.

As the slurry-like colored inorganic pigment for spray-coloring the ceramic fine hollow particles for coloring the foamed ceramic molded plate, glaze powder, feldspar powder, frit powder, zirconium silicate to which a color pigment and a metal oxide are added and mixed, etc. Can be used as a mixture with water or a solvent.
The spray coloring is applied to the entire surface of the ceramic fine hollow particles and dried.

[0028]

EXAMPLES Examples of the present invention will be described in detail below, but the present invention is not limited to the examples as long as the gist thereof is not exceeded.

Example A compressive strength of 700 kgf / cm ² or more and a bulk specific gravity of 0.3 to
0.5 g / cm ³ , melting point 1600 ° C., thermal conductivity 0.1
(Kcal / mhr ° C.) Consisting of 150 parts by weight of ceramic fine hollow particles composed only of completely hollow particles, 30 parts by weight of alkali silicate aqueous solution and 1.8 parts by weight of admixture (stabilizer, dispersant, etc.) The composition was thoroughly kneaded with an Omni mixer (manufactured by Chiyoda Giken Kogyo Co., Ltd.) to prepare a composition for a foam ceramic molded plate.

The particle size of the ceramic fine hollow particles was adjusted to 10 parts by weight of fine particles, 20 parts by weight of medium particles, and 30 parts by weight of coarse particles. The alkali silicate aqueous solution is Na ₂ O: 9.4 wt%,
An aqueous solution of sodium silicate composed of SiO ₂ : 29.4% by weight was used.

The composition for foamed ceramic molded plate is 1
It was molded by pouring into a mold having dimensions of 000 × 1000 × 30 mm and evenly applying a load of 100 kg / m ² . After molding, it was cured for 24 hours, demolded, and baked at 800 ° C. for 30 minutes to prepare a foam ceramic molded plate.

Comparative Example 1 Shirasu balloon (manufactured by S Co.) was used in place of the ceramic fine hollow particles used in the examples. Others are exactly the same as the embodiment.

Comparative Example 2 Instead of the ceramic fine hollow particles used in the examples, glass balloons (manufactured by A company) were used. Others are the same as in the first embodiment.

Table 1 shows a comparison of various physical properties of Examples and Comparative Examples 1 and 2. Each of the produced specimens is 10
It is 00 × 1000 × 30 mm. The specific gravity of the foamed ceramic molded plate according to the present invention is 0.58 because the ceramic fine hollow particles are not broken at all, which is extremely lightweight. Since the hollow hollow foam is originally one-third by weight and one-half by volume, the shirasu balloon becomes very heavy at 1.02 due to breakage due to molding. Glass balloon is about 60%
It can be said that the above became heavy because it was destroyed.

[0035]

[Table 1]

The compressive strength of the example is the strongest, and the comparative examples are about half of those of the example. When air was applied from the front surface to the back surface of the foamed ceramic molded plate at an air pressure of 1 kg / cm ² , it was tested whether or not the air penetrated from the front surface to the back surface.

The water absorption of each test piece and the results of the water permeability test from the front surface to the back surface are shown by weight ratio. The examples show that up to 120% of the weight of the foamed ceramic molded plate is absorbed, and at the time of 108% water absorption, water from the front surface oozes out to the back surface.

The flame front of a gas burner was applied to each sample, and the temperature of the back surface was measured. The tip of the gas burner is about 1
The flame irradiation time at 200 ° C. is 10 minutes. In the case of the embodiment, the air raised by the flame spreads over the entire foam ceramic molded plate, and the temperature rise on the back surface is extremely low.

[0039]

As described above, the foamed ceramic molded plate according to the present invention is made of fine micro-capillary of micron unit which is lightweight by using high strength ceramic fine hollow particles and has high strength and allows air to flow. The air circulation holes are stretched like a mesh. The foamed ceramic molded plate penetrates air but does not penetrate water and has a very high water absorption performance. The absorbed water does not seep outside and evaporates naturally. For this reason, even if the foam ceramic molded plate is placed horizontally and water is dropped from the front surface, the saturated water absorption amount of the foam ceramic molded plate does not drop from the back surface. Further, it is an excellent foamed ceramic molded plate having excellent heat insulation performance and extremely low temperature rise on the back surface against a flame, and can be suitably used not only for various building members but also for filters, diffuser plates and the like.

Claims (2)

[Claims] 1. 100 to 300 parts by weight of a ceramic fine hollow crystenol having a compressive strength of 600 kgf / cm ² or more, a bulk specific gravity of 0.3 to 0.5 g / cm ³ , and a melting point of 1500 ° C. or more and an alkali silicate aqueous solution of 10 to 300 parts by weight. 700 to 1300 ° C. after kneading the composition consisting of parts and pouring into a mold and pressure molding.
A foamed ceramic molded plate characterized by being fired at. 2. A colored foamed ceramic molded plate is obtained by using colored ceramic fine hollow particles obtained by spraying and drying a slurry-like colored inorganic pigment on the ceramic fine hollow particles according to claim 1. Item 3. A foamed ceramic molded plate according to item 1.