JPH0769660A - Production of amorphous porous glass molded articles - Google Patents

Abstract

PURPOSE:To provide the amorphous porous glass molded articles having excellent strength, durability, etc., by mixing a glass raw material mixture and calcium silicate as a water slurry, molding the mixture by dehydration molding and drying and burning the moldings CONSTITUTION:The raw material mixture forming a glass phase is prepd. by mixing natural glass (fired foam), components selected from feldspar, frit and glass powder and components selected from clay, silica stone and slaked lime. Then, 100 pts.wt. the raw material mixture and 7 to 40 pts.wt. calcium silicate as a binder are mixed as the water slurry. After the mixture is molded by dehydration molding, the mixture is dried and burnt which the amorphous porous glass molded articles are obtd. As a result, the water slurry of the calcium silicate is used as the binder and, therefore, the easy molding is possible and the molded articles do not cause shrinkage, cracking, etc., when the molded articles are burnt. Lightweight heat insulating plates, etc., which have high strength and are resistant to staining are produced.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a glass molded body which can be widely used for buildings, furniture, civil engineering, etc., and more specifically, to foam a molded body obtained by dehydration shaping of a raw material slurry by firing. The present invention relates to a method for producing a glass formed body.

[0002]

2. Description of the Related Art Porous glass is lightweight and has excellent heat insulating properties and is widely used as a building material. Conventionally, a raw material mixture that melts to form a glass phase and a foam material are mixed with water, the mixture is placed in a molding frame, melt-foamed, and then cooled and deframed (Japanese Patent Laid-Open No. 59-199539). Is known,
With this method, shaping and deframing operations are not easy and the dimensional accuracy is poor, so polishing is necessary. In addition, the designability (shape) was limited.

On the other hand, there is also known a method in which a raw material mixture which is melted to form a glass phase and a foaming material are hydro-kneaded, and the mixture obtained is pressure-molded and then melt-foamed (Japanese Patent Laid-Open No. 3-30083).
112824). However, in this method, the molding pressure must be increased in order to obtain a molded product that can be handled, and as a result, a molded product having a large bulk specific gravity is foamed, so that the expansion ratio is increased, There are problems that the uniformity of bubbles is poor and that defects due to abnormal expansion are likely to occur.

[0004]

[Problems to be Solved by the Invention] Easy shaping and operation,
It is an object of the present invention to provide a method for producing an amorphous porous glass molded body that has a shaped body having high strength, excellent dimensional accuracy, and controllable foaming.

[0005]

Means for Solving the Problems The inventors of the present invention have made earnest studies in view of the above problems, and as a result, by using a calcium silicate water slurry as a binder, a handle plate having good handleability can be easily obtained. Can be molded, and when the shaped molded body is fired, the microcrystals of calcium silicate, which is the solid content of the calcium silicate water slurry, partially melt into the glass phase, help the bonding of the raw material particles, and promote uniform foaming, It has been found that a porous glass molded body having excellent dimensional accuracy and having excellent designability can be obtained by firing once if glaze is applied at the same time, and the present invention has been achieved.

That is, the gist of the present invention is to provide a method for producing an amorphous porous glass molded body by shaping a raw material mixture which is melted to form a glass phase into a predetermined shape, and then dried and fired. In the method for producing an amorphous porous glass molded body, the raw material mixture and calcium silicate are mixed as an aqueous slurry, and the mixture is shaped by dehydration molding.

The present invention will be described in detail below. Various materials can be used as the raw material mixture for forming the glass phase by melting, but it is preferable to use at least one selected from the following groups (a), (b) and (c). (A) Natural Glass, Natural Glass Fired Foam As natural glass, pearlite, obsidian, shirasu, anti-firestone, pumice stone, etc. are used, and as natural glass fired foam, perlite, shirasu balloon, etc. are used. These form the main skeleton of the foam. (B) Feldspar, frit, glass powder These can be added to promote vitrification, and potassium feldspar, albite, lithium feldspar, etc. are used as feldspar. The frit is preferably suitable for the firing temperature. The glass powder is a crushed product such as an artificial glass bottle or a glass plate, is available at low cost, and can be used as a substitute for a frit. (C) Clay, silica stone, slaked lime These can be added to adjust the firing temperature and the molten state. Clay and silica increase the firing temperature, and slaked lime has the effect of decreasing it.

Mixing of the components (a), (b) and (c) is as follows:
(A) is usually 10 to 90% by weight, preferably 20 to 7
0% by weight, (b) is usually 0 to 50% by weight, preferably
10 to 30% by weight, (c) is usually 0 to 70% by weight, preferably 10 to 50% by weight. Also,
Each of the components (a), (b) and (c) is used in powder form. Usually, crushed and mixed to a particle size of about 1 to 200 μm,
It is supplied as a powdery raw material mixture. Such a raw material mixture becomes a porous molded body when it is molded and fired. If the foaming material is not added to the raw material mixture, the air bubbles of the obtained amorphous porous glass molded body will be connected to the inside from the surface, and the water absorption will be large. In order to obtain an amorphous porous glass molded body having a low water absorption rate, it is desirable to use a foam material. When a foam material is used, the obtained amorphous porous glass molding has independent cells, almost no water absorption, and excellent freeze resistance.

As the foaming material, use is made of a material usually used for porous glass, such as carbonates such as calcium carbonate, magnesium carbonate and dolomite, sulfates such as zinc sulfate and aluminum sulfate, and carbides such as tungsten carbide and silicon carbide. However, carbides are particularly preferable. When calcium carbonate is used, it not only acts as a foaming material, but also has the action of adjusting the firing temperature and the molten state and lowering the firing temperature. The addition amount of the foaming material can be changed according to the bulk specific gravity and water absorbency of the target molded article, but normally, the addition amount of the foaming material is 0.1 to 5% by weight with respect to the raw material mixture. Depending on the case, the communication bubbles and the independent bubbles are mixed.

If desired, a pigment may be added to the raw material mixture. As the pigment, a metal oxide such as chromium oxide, titanium oxide, cobalt oxide, iron oxide, nickel oxide or manganese oxide, or a synthetic pigment prepared by mixing these, firing at high temperature and finely pulverizing can be used. Further, ferrite, metal powder, graphite or the like may be added in order to absorb electromagnetic waves and impart conductivity.

The most significant feature of the present invention is that the raw material mixture and calcium silicate are mixed as an aqueous slurry. As a mixing method, an aqueous calcium silicate slurry is usually mixed with the raw material mixture. It is preferable to use a calcium silicate water slurry in which a silicic acid raw material and a calcium raw material are added to a large amount of water and hydrothermally synthesized at a high temperature and high pressure, but calcium silicate crystals may be added to water, or a raw material mixture. After mixing with the calcium silicate crystal powder, water may be added to form a slurry. The slurry concentration of the calcium silicate water slurry is usually 2-1.
The particle size of the secondary particles is usually 20 to 300 μm, and the viscosity can be appropriately adjusted so that the viscosity is suitable for molding.

The amount of calcium silicate added is 10
5 to 50 parts by weight, preferably 1 to 0 parts by weight
0-40 parts by weight, added as a water slurry. If the addition amount is less than 5 parts by weight, the effect of addition is not sufficient,
The strength of the shaped blank after shaping is low, making it difficult to handle before and after firing. On the other hand, if it exceeds 50 parts by weight, the amount of calcium silicate as a binder becomes too much, the shrinkage of calcium silicate during firing is remarkable, and the shrinkage rate of the obtained molded product is 20.
% Will be exceeded. Such large shrinkage causes deformation and cracks in a large-sized forming plate. Further, the molded product obtained at this time is mainly composed of crystalline calcium silicate, and can no longer be called an amorphous porous glass molded product, and does not meet the purpose of the present invention.

When the raw material mixture and the calcium silicate water slurry are mixed, fibers such as pulp, glass fibers and carbon fibers, and polymer thickeners such as polyacrylamide, polyacrylate and carboxymethyl cellulose can be added. . The mixing order of the components to be added is not particularly limited, but it is operationally advantageous to gradually add the raw material mixture to the calcium silicate water slurry while stirring.

The mixture is molded into a desired shape while being dehydrated by drainage pressing, papermaking, extrusion, casting and the like. When using a drainage press, the press pressure is 8-50
kg / cm ² is preferred. If the pressing pressure is less than 8 kg / cm ² , it is difficult to obtain a handleable strength, and the strength is 50 k.
If it exceeds g / cm ² , the particulates in the raw material mixture are destroyed and the bulk specific gravity becomes excessive, which increases the expansion ratio, resulting in abnormal foaming or failure to foam to obtain the desired porous body. There is a risk that you will not be able to.

The shaped product thus shaped contains a large amount of water, and if it is baked as it is, it may cause cracks. Therefore, it is dried and then baked. The drying may be natural drying, but since it takes a long time, it is usually dried at a temperature of 60 to 160 ° C. for 6 to 24 hours to completely remove water.
The dried molded body may be left unglaze or may be glazed, dried and then fired. In the case of adding a foam material, in order to escape the gas generated during firing, a glaze with a high melting point is applied to the lower layer,
After drying, a glaze for makeup is applied on this and fired to obtain a beautiful molded product by firing once. Further, it is also possible to apply glaze to a molded body that has been fired without glaze and re-fire. With no addition of foam material, a beautiful glaze can be obtained with a single glaze.

The glaze used for glaze is Na ₂ O,
K ₂ O, CaO, PbO, B ₂ O ₃ , MgO, ZnO,
Frit containing Al ₂ O ₃ , SiO _{2 and the} like as clay,
Frit glaze mixed with silica stone, feldspar, pigment, etc. is used, but addition of low expansion lithium feldspar such as petalite, spodumene, eucryptite, etc. is effective for adjusting the thermal expansion coefficient of these glazes. .

If necessary, chromium oxide or titanium oxide may be used as a pigment.
Tan, cobalt oxide, iron oxide, nickel oxide, man oxide
Metal oxides such as guns, or high temperature by mixing these
A synthetic pigment or the like that is calcined and finely pulverized is usually used. Glazed
According to the usual method, spray gun, brush, roll coater
It can also be done by shifting. Apply glaze once
300 ~ 2500g / m per glazed ²,Preferably
500-1500g / m²Is. Too much coating amount
And the specific gravity of the glaze is large, the glazed plate obtained is heavy and light
It is not preferable from the viewpoint of quantity.

The molded product dried after glaze or the dried product without glaze should be sprinkled evenly with fine powder of alumina, mullite, silica stone, chamotte, silica sand or the like to prevent sticking after firing. Alternatively, place on a smooth baking shelf lined with ceramic paper and fire in a roller hearth kiln or a truck loading tunnel kiln. Although firing can be performed using a shuttle kiln or an electric kiln, the above two are advantageous in terms of manufacturing cost. At this time, the flatness of the product is determined by the flatness of the shelves, so it is necessary to have sufficient flatness.

The firing temperature is usually 650 to 1280 ° C, preferably 700 to 1200 ° C. At 650 ° C. or lower, the dehydration reaction of xonotlite or tobermorite forming calcium silicate is insufficient, the reaction between the dehydration decomposition product and the raw material mixture is insufficient, and sufficient strength cannot be obtained. Further, when the temperature exceeds 1280 ° C, the temperature is too high, and therefore, after the foaming is completed, the melting progresses and the foam is removed.
It is not preferable because the weight cannot be reduced and the shape collapses. After this, according to a conventional method, cutting and processing such as mounting and fixing are performed. The amorphous porous glass molded body of the present invention thus obtained has a bulk specific gravity of 0.5 to 1.4, a bending strength of about 120 to 350 kg / cm ² , and is lightweight. Since it has excellent heat insulation properties, it is suitable for buildings, furniture, civil engineering, etc.

[0020]

EXAMPLES The present invention will be described in more detail with reference to examples below, but the present invention is not limited to the following examples unless it exceeds the gist thereof.

(Example 1) A calcium silicate water slurry (solid content concentration 6.3%, almost zonotolite composition) is shown in the table.
Raw material powders having the composition shown in 1 were mixed to obtain a slurry having fluidity suitable for molding. This was subjected to pressure dehydration for 3 minutes at a pressure of 8 kg / cm ² with a 50t filtered water press manufactured by Oji Machine Co., Ltd. to obtain a molded product having a 220 mm square and a thickness of 15 mm.

After drying this at 80 ° C. for 4 hours and then at 120 ° C. for 3 hours, 65 g of glaze having the composition shown in Table 3 A was prepared and sprayed on both the front and back sides with a spray gun. When the moisture of the coating material is absorbed by the base and it is possible to touch it,
The glaze shown in Table 3E was again sprayed with a spray gun. The coating amount at this time was 26.2 g. This is dried at 105 ° C for 4 hours and then at 780 ° C for 8 hours in an electric furnace.
It was held for 0 minutes and baked.

The fired product thus obtained had a smooth glaze surface, a bulk specific gravity of 0.82, a water absorption rate of 1%, a bending strength of 185 kg / cm ² , and a shrinkage rate of about 5%. there were. In addition, when X-ray diffraction analysis was performed, tobermorite, xonotlite, or
It was confirmed that these dehydrated calcium silicates were almost nonexistent and that they were almost completely vitrified by leaving a very small amount of insoluble components such as silica. For the water absorption rate, a sample piece whose weight was measured in advance was put in water at 20 to 25 ° C.
After 4 hours, this was taken out, the weight was measured again, and the weight change before and after the addition in water was expressed in percentage.

(Examples 2 to 3) In Example 1, the pressing pressure at the time of molding was 20 kg / cm ² in Example ² , and in Example 3
Was 50 kg / cm ² . Further, the same glaze as in Example 1 was used, and the spray amount was 61.4 g in Example 2 and 74.4 g in Example 3 for the first spray (glaze A), and 23. It became 4 g and 30.2 g. The obtained fired product has a smooth glaze surface, a bulk specific gravity of 0.75 and 0.72, a water absorption rate of 0.5% and 2%, and a bending strength of 179 k.
The values were g / cm ² and 172 kg / cm ² .

(Examples 4 to 6) The mixing ratio of the raw materials was in accordance with each example in Table 1 and the pressing pressure at the time of molding was 8 kg / mm in Example 4.
cm ² , Example 5 is 20 kg / cm ² , Example 6 is 50
It was set to kg / cm ² . After drying in the same manner as in Example 1, only glaze E was applied. The spraying amount at this time was 32.4 g in Example 4, 31.4 g in Example 5, and 34.
It became 6g. Then, firing was performed under the same conditions as in Example 1.

The fired product obtained had a glaze surface having a smooth luster, and in the order of Examples 4, 5 and 6, the bulk specific gravities were 0.74, 0.78 and 0.89, respectively, and the water absorption rate was 95%, 80%, 58% respectively, bending strength is 135 respectively
kg / cm ² , 148 kg / cm ² , 182 kg / cm
^{Was 2} . Since no foam material was used, the water absorption rate was high.

(Examples 7 to 9) The raw materials were mixed according to the formulation of each example in Table-1, and the pressing pressure at the time of molding was 8 in Example 7.
kg / cm ² , Example 8 is 20 kg / cm ² , Example 9
Was 50 kg / cm ² . The molded body was dried in the same manner as in Example 1, and then the glaze B was applied first. The spraying amount at this time was 56.6 g in Example 7 and 60.4 g in Example 8.
g, and Example 9 was 59.0 g. Next, 27.1 g, 25.3 g, and 23.6 g of glaze F were sprayed, respectively. Further, in both cases, firing was performed at 900 ° C. for 70 minutes. The obtained baked product had a glaze surface having a smooth luster, and the bulk specific gravities were 0.72 and 0.6, respectively, in the order of Examples 7, 8 and 9.
8, 0.65, the water absorption rate is 1%, 1%,
0.8%, bending strength of 169 kg / cm
² , 172 kg / cm ² and 181 kg / cm ² .

(Examples 10 to 12) The raw material powders were mixed according to the formulation of each example in Table 1, and the pressing pressure at the time of molding was 8 kg / cm ² in Example 10 and 20 kg / cm in Example 11.
² and Example 12 were 50 kg / cm ² . After drying in the same manner as in Example 1, the glaze F was applied only once. The spraying amount at this time was 26.0 g in Example 10 and Example 11
Was 27.5 g and Example 12 was 26.8 g. Further, in both cases, firing was performed at 900 ° C. for 70 minutes. The fired product obtained had a glaze surface having a smooth luster, and
The bulk specific gravities are 0.70 and 0.7 respectively in the order of 11 and 12.
The bending strength is 151 kg /
It was cm ² , 171 kg / cm ² , and 195 kg / cm ² . The water absorption rate was 85%, 81%, and 59%, which were large values.

(Examples 13 to 15) The raw materials were mixed according to the formulation of each example in Table-2, and the press molding machine used was a semi-drainage type 300t manufactured by Amada Co., Ltd. Example 13 is 8 kg / cm ² , Example 14 is 20 kg / cm
^2, Example 15 to obtain a molded product having a thickness of 20mm at 500mm square at 50 kg / cm ^2. 80 ℃ for 5 hours, 1
It was dried at 20 ° C. for 3 hours, and the glaze C was used first. The spraying amount at this time was 372 g in Example 13 and 3 in Example 14.
58 g, and Example 15 weighed 394 g. Next, glaze G
171 g, 169 g, and 158 g were applied. Then, after drying at 105 ° C. for 60 minutes, baking was performed at 1050 ° C. for 60 minutes. The obtained fired product had a glaze surface having a smooth luster, the bulk specific gravities were 0.72, 0.75 and 0.88, respectively, in the order of Examples 13, 14 and 15, and the water absorption rate was 0.6. %, 0.6%, 4% with bending strength of 13%
9 kg / cm ² , 141 kg / cm ² , 221 kg / c
It was m ² .

(Examples 16 to 18) The ingredients are listed in Table-2.
According to each of the examples, a semi-drainage type 300t manufactured by Amada Co., Ltd. was used as a press molding machine, and the press pressure at the time of molding was 8 kg / cm ² in Example 16 and 20 kg / c in Example 17.
m ² and Example 18 were 50 kg / cm ² to obtain a molded product of 500 mm square and 20 mm thick. This at 80 ℃ 5 hours,
After drying at 120 ° C. for 3 hours, the glaze was applied.

G was used as the glaze and was applied only once. The spraying amount at this time was 153 g in Example 16 and Example 1
7 was 172 g, and Example 18 was 394 g. After that, it was dried at 105 ° C for 6 hours and then at 1050 ° C for 6 hours in an electric furnace.
It was held for 0 minutes and fired. The obtained fired product had a glaze surface having a smooth luster, and in the order of Examples 16, 17, and 18,
The bulk specific gravities are 0.62, 0.67 and 0.81, respectively, the water absorption is 78%, 68% and 54%, and the bending strengths are 138 kg / cm ² , 151 kg / cm ² and 18, respectively.
It was 9 kg / cm ² .

(Examples 19 to 21) The ingredients are listed in Table-2.
According to the respective examples, the semi-drainage type 300t manufactured by Amada Co., Ltd. was used as the press molding machine, and the press pressure at the time of molding was 8 kg / cm ² in Example 19 and 20 kg / c in Example 20.
m ² and Example 21 were 50 kg / cm ² to obtain a molded product of 500 mm square and 20 mm thick. This at 80 ℃ 5 hours,
After drying at 120 ° C. for 3 hours, the glaze was applied twice. In this situation, the glaze was initially D, and the spray amount was 410 g in Example 19, 389 g in Example 20, and Example 21.
Was 391 g. Next, 138 g, 146 g, and 153 g of glaze H were applied on each of them. After this, 1
After drying at 05 ° C. for 6 hours, it was baked at 1135 ° C. for 70 minutes in an electric furnace. The obtained fired product had a glaze surface having a smooth luster, and the bulk specific gravities were 0.73, 0.70, and 0.69 in the order of Examples 19, 20, and 21, respectively, and the water absorption rate was 1.1. %, 1.3%, 1.4%, and bending strengths are 135 kg / cm ² , 139 kg / cm ² , 133, respectively.
It was kg / cm ² .

(Examples 22 to 24) The ingredients are listed in Table-2.
According to each of the examples, a semi-drainage type 300t manufactured by Amada Co., Ltd. was used as a press molding machine, and the press pressure at the time of molding was 8 kg / cm ² in Example 22 and 20 kg / c in Example 23.
m ² and Example 24, a molded product having a thickness of 20 mm and a size of 500 mm square was obtained at 50 kg / cm ² . This at 80 ℃ 5 hours,
After drying at 120 ° C. for 3 hours, the glaze was applied.

H was used as the glaze, and the spraying amount was 118 g in Example 22, 129 g in Example 23, and 107 g in Example 24. Then, after drying at 105 ° C for 6 hours,
Firing was performed by holding at 1135 ° C. for 70 minutes in an electric furnace. The fired product obtained had a glaze surface with a smooth luster, and
The bulk specific gravity is 0.72 in the order of 2, 23, and 24, respectively.
0.75 and 0.88, the water absorption rate is 68%, 62%,
42%, bending strength is 139 kg / cm ² , 1 respectively
It was 41 kg / cm ² and 221 kg / cm ² .

(Example 25) The same raw materials were used as in Example 8, the press molding machine used was a semi-drainage type 300t manufactured by Amada Co., Ltd., and the press pressure during molding was 20 kg / cm.
² was obtained to obtain a molded product of 500 mm square and 18 mm thick.
This is dried at 80 ℃ for 5 hours, 120 ℃ for 3 hours, and then 900 ℃
Firing was performed under the condition of holding for 70 minutes, and the glaze was applied. I was used as the glaze and was applied only once. The spray amount at this time was 148 g. After this, 60 at 105 ℃
After minute drying, it was baked at 700 ° C. for 60 minutes. The obtained fired product has a smooth glaze surface, a bulk specific gravity of 0.71, a water absorption rate of 1%, and a bending strength of 168 k.
It was g / cm ² .

(Example 26) The same raw material composition as in Example 20 was used, the press molding machine used was a semi-drainage type 300t manufactured by Amada Co., Ltd., and the press pressure during molding was 20 kg / cm.
² , a molded body having a size of 500 mm square and a thickness of 20 mm was obtained.
After drying at 80 ℃ for 5 hours and 120 ℃ for 3 hours, 1135
Firing was performed under conditions of 70 ° C. for 70 minutes, and the glaze was applied. The glaze used was J and was applied only once. The amount of spraying at this time was 127 g. After this, 60 at 105 ℃
After minute drying, it was baked at 950 ° C. for 60 minutes. The obtained fired product has a smooth glaze surface, a bulk specific gravity of 0.76, a water absorption rate of 1%, and a bending strength of 136 k.
It was g / cm ² .

[0037]

[Table 1]

[0038]

[Table 2]

[0039]

[Table 3]

[0040]

According to the present invention, by using calcium silicate water slurry as a binder, it is possible to easily shape it, and there is no shrinkage or cracking when fired, resulting in strength. In addition, it is possible to industrially provide a lightweight heat insulating plate that has excellent durability, has a variety of glaze designs, and is resistant to dirt.

Claims (7)

[Claims] 1. A method for producing an amorphous porous glass molded body by shaping a raw material mixture which is melted to form a glass phase into a predetermined shape, and then dried and fired,
A method for producing an amorphous porous glass molded body, which comprises mixing the raw material mixture and calcium silicate as a water slurry, and then shaping the mixture by dehydration molding. 2. A raw material mixture which is melted to form a glass phase is prepared by blending at least one of the following groups (a), (b) and (c). A method for producing an amorphous porous glass molded body. (A) Natural glass, natural glass fired foam (b) Feldspar, frit, glass powder (c) Clay, silica stone, slaked lime 3. The amorphous material according to claim 1, wherein 7 to 40 parts by weight of calcium silicate is mixed as a water slurry with respect to 100 parts by weight of the raw material mixture which is melted to form a glass phase. A method for producing a porous glass molded body. 4. The concentration of calcium silicate in water slurry is from 2 to 2.
It is 10 weight%, The manufacturing method of the amorphous porous glass molded body of Claim 1 characterized by the above-mentioned. 5. The method for producing an amorphous porous glass molded body according to claim 1, wherein the firing temperature is 650 to 1280 ° C. 6. 100 parts by weight of a raw material mixture that melts to form a glass phase is mixed with 7 to 40 parts by weight of calcium silicate as a water slurry, and the mixture is dehydrated and shaped into a predetermined shape. A method for producing a glazed amorphous porous glass molded article, which comprises drying the shaped body, or after drying and firing, at least one surface of which is glazed and further fired. 7. The method for producing an amorphous porous glass molded body according to claim 1, wherein the raw material mixture which is melted to form a glass phase contains a foaming material.