JPH0959077A - Expanded ceramic formed plate - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain the subject formed plate, passing air therethrough without passing water, having high water absorptivity, excellent in heat insulating performances and having a low temperature rise on the back surface in a fire by blending specific ceramic fine hollow particles with an aqueous solution of an alkali metallic silicate, Portland cent and water in a prescribed proportion, press forming the resultant blend and then baking the formed product. SOLUTION: A composition comprising 100 pts.wt. ceramic fine hollow particles having >=600kgf/cm<2> compressive strength, 0.3-0.5g/cm<3> bulk specific gravity and >=1500 deg.C melting point (e.g particles, containing 50-60% silica, 40-45% alumina and 1.5-2.5% others and colorable with a color inorganic pigment), 40-200 pts.wt. aqueous solution of an alkali metallic silicate (9.4wt.% Na2 O and 29.4wt.% SiO2 ), 50-300 pts.wt. Portland cement and 20-150 pts.wt. water is press formed under 50-500kgf/cm<2> , then cured for 1-10hr and subsequently baked at 300-700 deg.C to afford the objective lightweight formed plate having a high strength (and 0.5-0.7g/cm<3> specific gravity).

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The present invention relates to building and civil engineering members such as outer wall materials, flooring materials, ceiling materials, roofing materials, sound absorbing materials, tile base materials and water-permeable pavement materials used for buildings, and other filters.
The present invention relates to a foam ceramic molded plate used as an air diffuser plate or the like.

[0002]

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

A foamed ceramic molded plate obtained by adding a porosifying agent or a foaming agent to a slurry containing ceramic powder and a binder, and molding and firing this slurry. Further, a ceramic porous molded plate in which an inorganic fine foamed material, ceramic fragments, and the like are bonded by a binder is widely used.

[0004] However, in the case of using natural minerals such as porcelain stone, feldspar and clay as a raw material, good quality materials are gradually decreasing and it is difficult to obtain them. Further, in the method using a 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 diameter, and the porosifying agent is dispersed in the slurry and scattered during firing. 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 hollows as designed. Inorganic microfoam or ceramic shards that are bound by a binder have irregular shapes such as inorganic microfoam or ceramic shards, and the surface of these is not smooth, which results in large absorption of binder 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 has a fine void inside the ceramic molded plate, or 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 the diffuser plate and the one intended for a filter, conversely, there are only large air circulation holes. He had no resistance.

Japanese Patent Publication No. 5-59061 discloses a technique for press-molding baked vermiculite or shirasu balloon with water glass and a water glass curing agent, but shirasu balloon has a compressive strength of only 80 kgf / cm ² and a weight of 2 minutes. No. 1, 1/3 of the volume is unfoamed. For this reason, the shirasu balloon is further destroyed during the kneading of the raw materials and the pressure molding, and the weight of the molded body cannot be reduced. Furthermore, it is impossible to form point-to-point contact between the foamed hollow particles to form fine capillary-shaped air flow holes in the micron unit through which air flows.

Since the calcined vermiculite is a mere open-bore foam, it cannot be lightened by simply hardening it with water glass, and since it is not a hollow hollow particle, it naturally forms fine capillary air-flowing holes of micron unit through which air flows. It is not possible.

Further, the water glass curing agent used in JP-B-5-59061 cannot be industrially used because it is a deleterious substance such as sodium fluorosilicate.

[0010]

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 having a 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 pass through but does not allow water to pass therethrough, has extremely high water absorption performance and excellent heat insulation performance, and has an extremely low backside temperature rise against a flame. To aim.

[0011]

[Means for Solving the Problems] The above-mentioned problem is that the foamed ceramic molded plate is composed of innumerable perfect spherical fine hollow particles, and the fine hollow particles are connected to each other by points, so that microcapillary capillaries are provided between the fine hollow particles. It is possible to solve the problem by having the air flow holes in the shape of a circle.

According to the present invention, innumerable micron-sized capillary air flow holes are held in a foamed ceramic molded plate, and high-strength ceramic fine hollow particles are formed from an alkali metal silicate aqueous solution, Portland cement and water. The resulting composition is pressure-molded and cured for a predetermined period of time at 300 to 700 ° C.
It is fixed by firing at.

That is, 100 parts by weight of ceramic fine 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, an alkali metal silicate aqueous solution of 40 to 200 parts by weight, and Portland semé. 50 to 300 parts by weight of water and 20 to 150 parts by weight of water are kneaded, pressure-molded at a pressure of 50 to 500 kgf / cm ² , and then cured at 300 to 700 ° C. for 1 to 10 hours. To do.

The colored expanded ceramic molded article can be made into a colored expanded ceramic molded plate by using colored ceramic fine hollow particles obtained by coating fine inorganic ceramic particles with colored inorganic pigment in advance.

[0015]

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

The compressive strength of the ceramic fine hollow particles or the fine hollow foam is synonymous with the water pressure resistance, and the compressive strength is measured by pressing the fine hollow foam in water and applying the pressure applied to the water to the fine hollow foam. The pressure transmitted to the foam and broken by the fine hollow foam is defined as the compressive strength.

The foamed ceramic molded plate capable of exhibiting excellent performance must have a sufficient stirring / kneading process, and is particularly important for a foamed ceramic molded plate of a uniform product and of good quality. It is said that the stress and the shearing force applied to the ceramic fine hollow particles when the composition as described in the present invention is sufficiently stirred and kneaded will be about 400 kgf / cm ² . Since no conventional fine hollow foam can withstand such a high pressure, none of them can be used as such a foamed ceramic molded plate and have sufficient performance. That is, most of them are destroyed.

Next, when the ceramic fine hollow particles are used in the foamed ceramic molded plate, what is important is thermal conductivity. Fine hollow foams generally have a particle size of 0.1
(Kcal / mhr ° C.), and when half of the filled fine hollow foam is broken, the thermal conductivity drops to about 0.2 (kcal / mhr ° C.). Excellent effects can only be obtained if a completely fine hollow foam which is not destroyed 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. 100 hollow particles
% Perfect spherical. The compressive strength of the conventional fine hollow foam is 80 to 300 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 600k
If it is gf / cm ² or more, its melting point must be 1500 ° C. or more.

As described above, the ceramic fine hollow particles used in the present invention are 50 to 60% of silica and 40% of alumina.
, A foamed ceramic composition consisting of 1.5% to 2.5% and a compression strength of 700 kgf / cm ² , a melting point of 1600 ° C., and a bulk density of 0.3 to 0.3%. 5 g / cm ³ , thermal conductivity 0.1 (kcal
/ Mhr ° C) and consists only of completely hollow particles.
The fine ceramic hollow particles used have a particle size in the range of 12 to 350 μm, fine 12 to 75 μm, and 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 metal silicate aqueous solution used in the present invention forms an excellent and strong glassy film, and the general formula is represented by M ₂ O.mSiO ₂ .nH ₂ O. There are sodium, potassium, lithium, etc., and there is a special quaternary ammonium salt.

By adding an alkali metal silicate aqueous solution and Portland cement to the ceramic fine hollow particles, Portland cement effectively acts as a curing agent for the alkali metal silicate aqueous solution to shorten the curing time and facilitate handling after molding. Can be done. Further, water can adjust the fluidity of the present composition and facilitate the placement on a molding frame or the like.

As for Portland cement, an alkali metal silicate aqueous solution is hardened as a hardening agent in a short time, and then a hardening product which is stable for a long term can be formed by hardening by hydration reaction of Portland cement.

The ceramic fine hollow particles are molded and hardened with an aqueous alkali metal silicate solution and Portland cement, and after curing for 1 to 10 hours, the hardened portion of the alkali metal silicate is insoluble in water by firing at a low temperature of 300 to 700 ° C. It is possible to form a stable melt of the above, and to form cavities by countless minute bubbles in the foam ceramic molded plate.

The alkali metal silicate aqueous solution is added in an amount of 40 to 200 parts by weight with respect to 100 parts by weight of the ceramic fine hollow particles. If the amount is less than 40 parts by weight, the ceramic fine hollow particles cannot be fixed to each other by point bonding and sufficient strength cannot be exhibited in a short time. When the amount is 200 parts by weight or more, the solidified portion becomes large, and it becomes impossible to make an innumerable capillary-shaped air flow hole exist in a portion other than the point-joining of the ceramic fine hollow particles.

Portland cement is added in an amount of 50 to 300 parts by weight based on 100 parts by weight of ceramic fine hollow particles. Portland cement is used as a curing agent for an alkali metal silicate aqueous solution, and 50 parts by weight is sufficient for curing an alkali metal silicate aqueous solution and for forming a long-term stable hardened body by a hydration reaction after forming a melt. However, if the amount is 300 parts by weight or more, innumerable capillary air circulation holes cannot be made to exist in the portion other than the point-joining of the ceramic fine hollow particles.

When whiteness is required for the surface of the foamed ceramic molded plate, white cement can be used instead of Portland cement.

Water not only enhances the fluidity of the composition and improves workability and moldability, but also effectively acts on the hydration reaction of Portland cement. In addition to the above, in order to improve the properties of the composition and the physical properties of the foamed ceramic molded plate, a dispersant, a thickener, an antibacterial / antifungal agent, a stabilizer, other admixtures, an inorganic extender pigment, etc. are added. Good.

The colored inorganic pigment can be easily coated on the ceramic fine hollow particles by adding the colored inorganic pigment and water to the ceramic fine hollow particles and mixing and stirring with a tumbling mixer. The colored inorganic pigment used in the present invention is 4
Fine powder of 4 pm or less, such as cobalt pigment, iron pigment, chromium pigment, manganese pigment, copper pigment, vanadium pigment, mercury pigment, lead pigment, sulfide pigment, selenide pigment, for example, aureolin (yellow) , Cobalt Green (green), Cerulean Blue (sky blue), Cobalt Blue (blue), Cobalt Violet (purple), Ocher (yellow), Schner (cut), red iron oxide (red), Prussian blue (blue), chromium oxide ( Green), yellow lead (yellow), pyridian (green), mineral violet (purple), emerald green (green), vanadium yellow (yellow), vanadium blue (blue), sh (red), red lead (red), cadmium Yellow (yellow), ultramarine (blue), cadmium red (red), carbon black (black), etc. can be used.

The foamed ceramic molded plate may be continuously molded by placing the composition in a mold of a predetermined shape and pressure-molding it with a press or by supplying the composition on a conveyor and pressing it with a roll. Is also possible. After pressure molding, it is cured for 1 to 10 hours, and then fired at a low temperature of 300 to 700 ° C.

The foamed ceramic molded plate is extremely light in weight because its fine ceramic hollow particles of high strength are joined together and this part is fixed by the melt of the alkali metal silicate aqueous solution and the cured product of Portland cement. Is 0.5 to 0.7 (g / cm ³ ). Also 50 at the time of molding
Since the pressure is applied at up to 500 kgf / cm ² , the foamed ceramic molded plate becomes dense and has high strength.

The high-strength ceramic fine hollow particles can be completely present in the foamed ceramic molded plate in the form of a hollow body. It was found that there are innumerable capillary-shaped air circulation holes.

Due to the innumerable mesh-like capillary air circulation holes, air flows from the surface of the foam ceramic molded plate even at a low air pressure of only about 1 kgf / cm ² . That is, air from the front surface flows not only to the back surface of the foamed ceramic molded plate but also to the four circumferences of the foamed 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.

For this reason, even if a flame is applied to the surface of the foamed ceramic plate according to the present invention, high-heat air due to the flame flows evenly over the foamed ceramic molded plate, and the rise in the back surface temperature is small, and the foamed ceramic molded plate is entirely radiated. Acts as.

When the foamed ceramic molded plate is placed horizontally and water is dripped on its surface, the dripped water can be immediately absorbed. That is, the water dripped into the capillary-shaped air flow 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 circulation 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.

[0036]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below in detail, but the present invention is not limited to the embodiments unless it exceeds the gist.

Example: Only a completely hollow particle having a compressive strength of 700 kgf / cm ² , a bulk specific gravity of 0.3 to 0.5 g / cm ³ , a melting point of 1600 ° C. and a thermal conductivity of 0.1 (kcal / mhr ° C.). To 100 parts by weight of the ceramic fine hollow particles, 80 parts by weight of an alkali metal silicate aqueous solution, 150 parts by weight of Portland cement, and 75 parts by weight of water, 1.2 parts by weight of a dispersant and a stabilizer as an admixture were added and stirred. After sufficiently stirring and kneading the composition, it is cast into a mold to form a plate 3
It was pressure molded at a pressure of 00 kgf / cm ² . After pressure molding, the material was aged at room temperature for 2 hours and then baked at 540 ° C. for 30 minutes to prepare a foamed ceramic molded plate.

The size of the foam ceramic molded plate is 500 × 5.
It is 00 × 30 mm. The fine ceramic particles used were fine-grained 6 parts by weight, medium 59 parts by weight, and coarse 35 parts by weight. Alkali metal silicate aqueous solution is commercially available Na ₂ O 9.4 wt%, SiO ₂ 29.4 wt%
Was used.

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

Table 1 shows a comparison of various physical properties of Examples and Comparative Examples 1 and 2. Each of the produced specimens is 500
It is × 500 × 30 mm. The specific gravity of the foamed ceramic molded plate according to the present invention is 0.63 because the fine ceramic hollow particles are not broken at all, which is extremely lightweight. Originally, the hollow hollow foam had a weight of 1/3 by weight and a volume of 1/2, and most of it was destroyed by stirring, kneading, and pressure molding, resulting in a very heavy specific gravity of 1.44. It can be said that the glass balloon was destroyed by about 60% and became heavier.

[0042]

[Table 1]

The compressive strength is the highest in the example, and in the comparative example, the balloons are broken so that the bonding due to the hardened components is not completely performed and the sufficient strength cannot be exhibited. Air pressure 1kgf from front to back of ceramic foam plate
As a result of testing whether or not air permeates from the front surface to the back surface when air is applied at / cm ² , only the examples are permeated, and the comparative examples are microcapillary in the micron unit inside due to the destruction of the balloon. No air flow holes were generated and the air could not permeate.

The water absorption rate of each test piece and the result of the water permeability test from the front surface to the back surface are shown by weight ratio. The examples show that up to 107% of the weight of the foamed ceramic molded plate is absorbed, and at the time of absorbing 105% of the weight, water from the front surface exudes to the back surface.
In each of the comparative examples, water permeability was not possible because fine capillary-shaped air flow pores in the micron unit were not formed in the molded product and it was an incomplete foam.

The flame front of a gas burner was applied to each test piece to measure the temperature of the back surface. The tip of the gas burner is about 12
Flame irradiation time at 00 ° 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.

[0046]

As described above, the foamed ceramic molded plate according to the present invention is made of fine micro-capillary particles of micron unit which are made lightweight by using high strength ceramic fine hollow particles and have high strength and allow air to flow therethrough. 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 absorbing performance, and the absorbed water does not seep outside and evaporates naturally. Therefore, 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 drip from the back surface. Further, it is an excellent foamed ceramic molded plate which has excellent heat insulating properties and has a very low temperature rise on the back side against a flame, and can be suitably used not only for various building members but also for filters, diffuser plates and the like.

[Brief description of drawings]

FIG. 1 is an enlarged cross-sectional view of a foam ceramic molded plate of Example 1.

[Explanation of symbols]

 1. 1. Ceramic fine hollow particles Air circulation hole 3. Cavity with minute bubbles 4. Hardened cement

Claims (2)

[Claims] 1. 100 parts by weight of ceramic fine 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 40 to 200 parts by weight of an aqueous alkali metal silicate solution. A foamed ceramic molded plate, comprising a composition of 50 to 300 parts by weight of Portland cement and 20 to 150 parts by weight of water, which is pressure-molded and then fired at 300 to 700 ° C. 2. The foamed ceramic according to claim 1, wherein a colored foamed ceramic molded plate is obtained by using the colored ceramic microhollow particles obtained by coating the ceramic microhollow particles according to claim 1 with a colored inorganic pigment. Formed plate.