JPH03112825A - Production of foamed glass plate - Google Patents

Abstract

PURPOSE:To obtain a foamed glass plate having smooth surface without requiring slice operation for adjustment of thickness and causing cutting loss by forming a mixture consisting of glass powder, sodium silicate powder, water soluble organic foaming agent and water into a flat glass under pressure, inserting into a space between opposite plates having a prescribed interval and burning and foaming the flat glass. CONSTITUTION:(A) Glass powder is blended with (B) sodium silicate (preferably having <=0.1mm particle size in >=95wt.% of both components A and B) so as to be in the range of molar ratio of Si/Na2O of 3.93-5.14. (C) Foaming agent (forming agent soluble in water at ordinary temperature and causing no evaporation on heating and then carbonizing to give CO2, e.g. saccharides such as sugar) and (D) water are added and blended with the components A and B at at amount of 1-30 pts.wt., preferably <=20 pts.wt. based on 100 pts.wt. total amount of the components A and B. The blend is formed into a flat glass under pressure (>=0.5kgf/cm<2>) and charged to opposite plates retained to prescribed intervals and burned and foamed to provide the foamed glass.

Description

Detailed Description of the Invention (a) Technical Field The present invention provides at least glass powder and sodium silicate powder 1.
A non-flammable, lightweight and heat-insulating product made by firing and foaming a molded plate obtained by pressurizing a mixture of a foaming agent and water.
The present invention relates to a method for manufacturing a foamed glass plate with excellent water resistance.

(b) Background technology In recent years, buildings have become taller and lighter and warmer construction materials are required, and lightweight concrete containing lightweight aggregate and aerated concrete such as ALC are widely used. ing. In particular, ALC building materials are lightweight,
In addition, the recent growth has been remarkable due to simplified construction methods, shorter construction periods, and excellent insulation properties. Moreover.

Needless to say, these concrete materials are non-combustible, and can be said to meet most of the conditions that should be met as building materials. However, these lightweight concrete materials cannot necessarily be said to have high strength at low specific gravity rings, and if the specific gravity is 0.5 or less, it is difficult to manufacture concrete plates that can withstand practical use.

Molded plates with a specific gravity of 0.5 or less include asbestos, rock wool, glass wool, wood chips, various fibers bonded with cement, plaster, calcium silicate, etc., as well as polyurethane, polystyrene, polyolefin, and other materials. However, the former has the disadvantage of being water permeable and absorbent, while the latter plastic foam has the disadvantage of not being non-flammable and exhibiting large creep deformation at high temperatures. Therefore, both are excellent insulation materials.

Although they are sound-absorbing materials, their range of use is limited due to their own drawbacks.

Foamed glass sheets are the only molded products that are lightweight, heat insulating, heat resistant, and non-water absorbing, and have a reasonable strength at a specific gravity of 0.5 or less, or a strength equivalent to specific gravity, and are in practical use. It is. In the field of construction, this foamed glass plate is embedded in RJs and walls to take advantage of its functions.

From the viewpoint of raw materials, the manufacturing method for foamed glass is: ■Glass powder is the main ingredient, to which some fluxing agents such as sodium silicate and boric acid and small amounts of blowing agents such as carbon black and calcium carbonate are added and fired. There are two methods: (1) using water glass as the main raw material, adding a polyvalent metal to it, and firing and foaming using water contained in water glass as a foaming agent.

Manufacturing from water glass as described in Chapter 2 foams at a relatively low temperature, so it has the advantage of being low cost, but it is inferior to water glass made from glass powder in terms of water resistance and strength, and is still not suitable for practical use. Not yet reached.

Foamed glass sheets that are currently in practical use have large bubbles, so there is no problem with using them in applications where they are buried inside buildings and the surface is covered with other materials. It is difficult to use in fields where it appears on the surface for decoration of objects.

That is, the surface of the foam glass plate can be painted or paper.

If it is used as a heat-insulating/sound-absorbing interior board for walls or ceilings by laminating cloth, leather, etc., it is preferable to have smaller air bubbles.One of the reasons is that the air bubbles are smaller in terms of feel, texture, and appearance. Another reason is that less adhesive is used.

Reducing the amount of adhesive used not only improves cost, but also helps reduce weight.

(C) Disclosure of the Invention The present inventor uses glass powder as the main raw material, adds sodium silicate powder, and a foaming agent to form a mixture, and conducts intensive research on pretreatment conditions and firing and foaming conditions up to firing and foaming. As a result of repeated research, we found that the use of water, its mixing conditions, and the presence or absence of pressure molding greatly affect its firing and foaming properties. We have systematized a method for obtaining a foamed glass plate with uniform distribution, and have completed the present invention.

One of the characteristics of the method of the present invention is that a smooth skin layer without bubbles is formed on both sides, thereby producing a foamed glass plate whose surface can be easily decorated.

Another effect obtained by carrying out the present invention is that a part of the step of cutting the foam board can be omitted, and cutting loss can therefore be reduced.

These advantages are that the pressure-formed plate placed between two facing plates fixed in parallel with a predetermined interval is pressed between the corner plates so that it cannot expand to the interval E. This is achieved by firing in the state.

The glass used in the method of the present invention is preferably alkali silicate glass. In particular, since factory waste glass and recycled glass can be obtained at low cost, it is also effective use of resources, and is extremely preferable. Of course, glass other than alkali silicate glass , such as borosilicate glass, lead glass, and silica sand made of silicon dioxide,
The softening temperature and melt viscosity of silica and other ores, feldspar containing a large amount of silicon dioxide, zeolite and other ores, or factory waste such as slabs and fly ash can be controlled by the addition ratio of the fluxing agent, sodium silicate. Therefore, the application of the present invention is running.

The size of the glass powder particles is 1. The finer the better, preferably 95% by weight or more of the particles are 0.11■
A fine powder having the following properties is preferable, because if there are many large particles, the molded plate after pressure molding will easily collapse and become difficult to handle.

Regarding the size of the particles of the sodium silicate powder used in the present invention, the finer the better. Sodium silicate acts as a binder for the pressure-formed plate, and is mixed with the foam material. , which increases foaming ability, is preferable to use fine particles that are advantageous for dissolution. Considering miscibility with glass powder, it is better to use particles close to the size of glass powder, and therefore more than 95% of them are 0.1 (2) It is desirable that the powder be fine as follows.

Regarding the composition of sodium silicate, if it can be made into powder, 5i02, Na, 0. It is not limited to a specific ratio of H and O, but should be determined by the composition ratio in the mixture of glass powder and sodium silicate powder, rather than by the amount added. The ratio is the respective oxide equivalent molar ratio of silicon and sodium [S i 027N
a = O] is preferably in the range of 3.93 or more and 5.14 or less. If the molar ratio is less than 3.83, the strength and water resistance of the glass plate will deteriorate significantly, making it impractical. . In addition, if the molar ratio exceeds 5.14, the firing temperature must be increased, which widens the gap between the combustion temperature of one blowing agent and the acid of the blowing agent that is wasted, resulting in a lightweight foam. cannot be obtained.

The blowing agent used in the present invention must first be soluble in water at room temperature, and carbonization can proceed without volatilization during evaporation from heating to firing, and it can also be combusted and converted into carbon dioxide gas. If it is a water-soluble blowing agent, at least the dissolved content is uniformly dispersed by adding ice and mixing, so it is more effective than mixing carbon black or calcium carbonate powder, which is not soluble in water. It is microdispersed, and it is easy to obtain a foam with many small bubbles evenly dispersed.Furthermore, the dissolved blowing agent mixes uniformly with the dissolved sodium silicate, and moisture is removed before or during firing. After evaporating, it is confined within the sodium silicate, and decomposition gas and combustion gas generated as the temperature rises are prevented from volatilizing and effectively contribute to foaming.

Examples of such blowing agents include sugar, glucose, fructose, polyvinyl alcohol, methylcellulose,
Examples include water-soluble polymers such as casein and albumin. Regarding implementation.

It is also possible to use two or more of these in combination.

In the present invention, addition of water is an absolute requirement. One of the effects of adding water is to uniformly disperse the fl foaming agent and confine it within the sodium silicate as mentioned above, and the other effect is to create a binder in which the sodium silicate is partially dissolved. Attach the machine number seven.

The object of the present invention is to facilitate the handling of pressure-formed plates.

The amount of water added is at least 1 part by weight, but not more than 30 parts by weight, preferably not more than 20 parts by weight, based on 100 parts by weight of the total amount of glass powder and sodium silicate powder. If it is less than 1, the compaction during pressure molding will not be sufficient and the pressure molded plate will easily collapse.

In addition, if compaction is not sufficient, it is difficult for the glass and sodium silicate to fuse and sinter, and decomposed gas and sintering gas generated from the blowing agent existing in the gaps between the glass particles are likely to dissipate, which means that the foaming efficiency will be reduced. bad.

If the amount of water added exceeds 30 parts by weight, the powder will no longer be mixed, and the mixing cost will increase significantly. Additionally, excess water results in energy loss by the amount of heat from the evaporation bath.

In the present invention, water plays an important role, but there are certain restrictions on its mixing conditions. Regardless of whether the glass powder and other raw materials coexist, it is necessary that at least the silicon soda powder, the blowing agent, and water be mixed substantially sufficiently in the presence of the three. The required mixing time varies depending on the performance and size of the mixer, so it is difficult to specify specific mixing conditions, but 2 For example, it is possible to mix sodium silicate and/or a blowing agent without contacting water and When pressed and fired, there are not many bubbles. If the foaming is insufficient when carried out by the method disclosed in the present invention, the mixing of the sodium silicate, blowing agent, and water was insufficient. , it can be determined that.

The molding pressure of the pressure molding carried out in the present invention must be at least 0.5 Kgf/c2.
If it is less than 0.5 Kgf/cm z, the compaction is insufficient, resulting in the disadvantage that the pressure-formed plate is likely to collapse, the foaming efficiency is poor, and there is a limit to the reduction in temperature.

In the present invention, when firing and foaming a pressure-formed plate, it is possible to dry the formed plate in advance or not.Water content is ultimately removed, but according to the present invention It is possible to obtain the desired foamed state no matter which step the water is removed in.

In the method of the present invention, in which the distance between two opposing fixing plates is maintained constant and a molded plate is fired between the front fixing plates, the plate surfaces of one fixing plate may be faced at ):'F, or Although they may be opposed front to back (or left and right), in reality, it is natural to lay the molded plates down and sandwich them one above the other, and then foam in the downward direction to control the thickness to a predetermined value. Both sides of the foamed board thus obtained are smooth and free of bubbles, making it convenient for painting or laminating decorative materials.

No special skills are required to make the distance between opposing fixed plates constant. For example, when baking in a baking mold, fix the ceiling plate with screws or set a spacer on top of it. You can use a method such as placing a top plate and then placing a weight of sufficient weight on top of it to resist the foaming pressure.Also, if a baking mold is not used, two belt conveyors moving in the same direction and at the same speed may be used. A method can be used in which a molded plate is placed between the two and moved in the firing furnace. If the interval between the two conveyors can be freely adjusted, a foam board of any thickness can be obtained.

In addition, in this invention, an oxygen donor can also be used together. It can be judged from the fact that the specific gravity of the molded plate is much lower than the specific gravity of the glass that the molded plate contains sufficient air, ie, oxygen, even after pressure forming. However, depending on conditions such as the degree of compaction, the amount of moisture immediately before firing, or when a dissolved foaming agent is encapsulated in sodium silicate, it is effective to supplement oxygen by using an oxygen donor in combination. By lightening the coloring caused by carbides,
You can see its effects.

Such oxygen donors include metal oxides such as manganese dioxide, potassium permanganate, ferric oxide, zinc sulfate,
Examples include sulfates such as aluminum sulfate, and nitrates such as ammonium nitrate, potassium nitrate, and sodium nitrate. All of these can release oxygen that participates in the combustion of carbides when heated to 200° C. or higher.

Hereinafter, the present invention will be specifically explained with reference to Examples.

(d) Examples Example 1 Glass powder obtained by crushing plate glass (particle size 62JL)
Anhydrous sodium silicate powder No. 1 powder (reprinted powder product smaller than 200 mesh was further ground for 30 minutes in a vibrating mill) to 100 parts by weight of the following particles (38.2% by weight or more)
10 weight 9 parts, commercially available powder sugar (cranu sugar 98
0.5 parts by weight of cornstarch (2%) and 0.5 parts by weight of manganese dioxide powder (for reagents and chemicals) were each put into a planetary screw mixer equipped with a lamp breaker and mixed for 30 minutes. .

To 100@71 parts of this powder mixture, 5 parts by weight of water was added and mixed in a kneader for 15 minutes to obtain a wet powder.

600g of this powder was put into a square mold with a side of 1601 mm, the T-side was smoothed, and a compression molding machine was used to produce 39Kgf/c■2
A pressure-formed plate having a thickness of 20 mm was obtained under the conditions of pressurization for 10 seconds.

This pressure-formed plate was dried at 40°C for 24 hours in an upright position with both sides exposed to the air.

The dried pressure-formed plate was cut out by cutting out 12.5 mm on each of the four sides and 5.2 mm on the bottom surface of F to a thickness of 9 mm.
．． A test piece with 4 layers and 135 mm on a side was used.

This dried pressurized test piece was
It was placed in a metal container whose inner surface was coated with alumina powder as a mold release agent. Spacers of 20 mm were placed at the four corners of the container, and a metal plate whose underside was coated with alumina powder equal to the area of the container was placed on top of the spacers. A 2.5 kg weight was placed on the metal plate, the whole container was placed in a furnace whose temperature had been pre-controlled at 200°C, the temperature was raised to 750°C over 3.5 hours, and the temperature was maintained at that temperature for 20 minutes. ,
The temperature was lowered to 30° C. over 5 hours and the foam was taken out.

The obtained foam was a rectangular plate whose top and bottom surfaces were flat and parallel to the gap.

A test piece with a side of 100 mm and a thickness of 20 cm was cut from this foam board. The bubbles seen in the cross section were spherical with a diameter of 0.81 mm or less, and had a uniform structure with a -like distribution. The specific gravity of the test piece is 0.230, and its compressive strength is 2
It was 5.0 Kgf/cmz. Therefore, the specific strength is 108.7 Kgf/Cm z.

Comparative Example 1 A test piece with a thickness of 20 cm, which was obtained by cutting out approximately 15 mm from each of the four sides of a dry pressure-formed plate obtained in the same manner as in Example 1, was placed on the inner surface with a - side of 210 cm and a depth of 50 mm. The mixture was placed in a metal container coated with alumina powder as a molding agent, a lid was placed on top of the container, and the entire container was placed in a firing furnace. The temperature profile for firing and foaming was the same as in Example 1.

The upper part of the resulting foam was spherical, especially at the periphery, and the overall specific gravity was 0.238. When a rectangular plate is made by cutting out the 1-sided part and making it smooth, the cut out part is 150
Although the foaming at 0 g was sufficient, there was a large loss when cutting off the top surface.

Example 2 The pressure-formed plate was fired immediately without drying.

Everything else was the same as in Example 1.

The obtained foam was a rectangular plate whose top and bottom surfaces were flat and parallel to each other.

A test piece with a thickness of 20 mm and a negative side of 100+ layers was cut from this foam board. The bubble seen in the cross section has a diameter of 1.0 ay.
It was spherical in size and had a uniform structure with a -like distribution. The specific gravity of the test piece was 0.201. The compressive strength determined from the test piece was 18.11 Kgf/c112. Therefore, the specific strength is 84. I Kgf/cs z
It is.

Comparative Example 2 200 g of the water-free powder obtained in Example 1 was placed in a square mold with sides of 100 mm, the top surface was smoothed, and the mixture was molded using a compression molding machine at 39 Kgf/c 2 for 10 seconds. A pressure-formed plate was obtained.

The upper and lower sides of this pressure-formed plate are 51 meters each, and the four sides are 20 meters long.
A test piece with a thickness of 10 cm and 60 cm on each side was obtained by cutting out the test pieces one by one.

This test piece was placed in a metal container with a side of 100m5 and a depth of 40cm coated with alumina, and the container was placed in a furnace pre-controlled at 300°C and heated to 710°C for 2 hours. After raising the temperature and maintaining the temperature for 20 minutes, the temperature was lowered to room temperature over 5 hours and the foam was taken out.

The specific gravity of the obtained foam was 1.12.

When no water was used, sufficient foaming could not be obtained.

Comparative Example 3 The same raw materials as in Example 1 were used. 200g glass powder
, powdered sugar tg, and 11 g of water were mixed in a mortar, and the mixed powder was dried at 40° C. for 24 hours. To this dry powder, 20 g of anhydrous sodium silicate No. 1 and 1 g of manganese dioxide were added and mixed. This powder mixture was then pressure-molded. Pressure molding and subsequent steps were carried out in exactly the same manner as in Comparative Example 2.

The specific gravity of the obtained foam was 0.924. Further, even when other powders were mixed with water without the anhydrous sodium silicate, foaming was insufficient.

Comparative Example 4 The same raw materials as in Example 1 were used. 200g glass powder
, 20 g of anhydrous sodium silicate No. 1, and ttg of water were mixed in a mortar, and the mixed powder was dried at 40° C. for 24 hours. This dry powder was mixed with 1 g of powdered sugar and Ig of manganese dioxide, and then this powder mixture was pressure molded.

Pressure molding and subsequent steps were carried out in exactly the same manner as in Comparative Example 1.

The specific gravity of the resulting foam was 1.34. Also.

Even when other powders were mixed with water without powdered sugar, foaming was insufficient.

Comparative Example 5 The water-containing powder kneaded in the kneader obtained in Example 1 was
It was dried at 0°C for 24 hours. Thereafter, the steps from pressure molding to firing were carried out in exactly the same manner as in Comparative Example 2 to obtain a foam.

The specific gravity of the resulting foam was 0.378.

As in this example, if sodium silicate, sugar, and water are sufficiently mixed in coexistence.

Foaming was also sufficient.

However, the top surface of the foam was not flat, and it was necessary to cut the top surface.

(e) Effects of the invention As seen in the above Examples and Comparative Examples, due to the interaction of sodium silicate, water-soluble blowing agent, and water, the mixture of them and glass powder becomes effective for the first time by heating and baking. It can be seen that it foams.

Furthermore, prior to firing and foaming, if a water-containing mixed powder is pressure-molded and then fired as is or after drying, a glass foam with fine bubbles and similar to the molded plate before firing can be obtained. found.

However, if foaming is allowed to occur freely without restrictions, it will not be completely similar to the molded plate, and the upper surface will swell into a slightly spherical shape, resulting in the need to slice the −E surface, which results in a loss. Become.

Therefore, in the method of the present invention, in order to limit the expansion in one direction during foaming, preferably in the direction where the thickness becomes a predetermined dimension, a fixed surface or A pressure surface is provided. This eliminates the slicing operation for adjusting the thickness and the cutting loss, and makes it possible to manufacture a foamed glass plate with a smooth surface.

Thus, according to the method of the present invention, it is possible to easily produce a foamed glass plate that is lightweight, has excellent heat insulation properties, has high specific strength, and has small and uniformly distributed bubble diameters that can be used as a board or panel base material for interior and exterior buildings. It can be manufactured to

Claims (1)

[Claims] A mixture consisting of at least glass powder, sodium silicate powder, a blowing agent made of an organic substance that is soluble in water and carbonizes below the firing temperature and eventually burns to become carbon dioxide gas, and water is pressure-molded into a plate shape. After that, the molded plate is inserted between two opposing plates installed to maintain a predetermined interval, and fired and foamed.