KR100536854B1 - Composition for foam glass and method for preparing foam glass precusor using them - Google Patents

Abstract

The present invention relates to a foamed glass composition and a method of manufacturing a foamed glass precursor using the same, and more particularly, to a foamed glass composition consisting of alkali hydroxide, silica and B (OH) ₃ and a method of manufacturing a foamed glass precursor using the same.

Foamed glass precursor prepared by the present invention exhibits excellent foaming performance without the use of a foaming agent, and in particular exhibits foaming performance at low temperatures can be used as a glass foam for heat dissipation and soundproofing and can be used in addition to various paints and paints.

In particular, when used in addition to various paints and paints, not only does it impart flame retardancy to the surface of the applied material, but also foams in case of fire, and has an effect of forming a foamed glass heat radiation film having a fire extinguishing function.

Description

Foamed glass composition and manufacturing method of foamed glass precursor using the same {COMPOSITION FOR FOAM GLASS AND METHOD FOR PREPARING FOAM GLASS PRECUSOR USING THEM}

The present invention relates to a foamed glass composition and a method for producing the foamed glass precursor using the same.

Foamed glass refers to a glass having a bubble structure in the glass. The glass has the characteristics of weather resistance, chemical resistance and heat resistance, and has a bubble structure in the original physical properties. And it is used as a material such as thermal insulation, cold insulation and corrosion resistant materials that require chemical resistance. Specifically, foamed glass is used as thermal insulation, cold insulation and internal materials for petrochemical plants, LNG liquefied gas tank bottoms, refrigerated warehouses and stacking linings.

In general, the process of foaming glass first mixes the glass powder of special composition and foaming agent well, puts it in the heat-resistant mold of a predetermined shape and heats it over the softening temperature of the glass. The glass softens and surrounds the foaming agent, and then gas is generated from the foaming agent. It becomes the foamed glass of the waste hole structure. The compound that can be used as a blowing agent includes calcium carbonate, calcium phosphate, carbon and the like.

Calcium carbonate and calcium phosphate decompose above the softening temperature of the glass to generate gaseous components, and carbon, on the other hand, act as a blowing agent by reacting and oxidizing with certain components in the glass above the softening temperature.

Looking at the manufacturing method of conventional foam glass is as follows.

In Korea Patent Registration No. 10-0194107, Domestic Patent Publication Nos. 1999-008535, 1999-006196, 1999-076196, 1996-041120 and 1997-69916, various glassy powders are prepared at 700 to 1200 ° C. It describes a method of producing foamed glass by firing at high temperature to form a closed pore structure between the glass particles, and press molding at a high temperature by adding a blowing agent to increase the foaming efficiency.

Korean Patent Laid-Open Publication No. 2000-0050105 describes a method for forming an ultrafine waste pore structure by foam molding a porous silica gel prepared by a sol-gel method at about 1000 ° C.

In addition, Japanese Patent Laid-Open Publication No. 1994-279056 describes a method of mixing and drying a glass component containing a blowing agent in a slurry state at a low temperature and then foaming at a high temperature in a kiln.

Japanese Patent Laid-Open No. 1999-106223 describes a method of pulverizing waste glass, mixing with a blowing agent, and then foaming at a high temperature of 800 to 1100 ° C.

Japanese Patent Laid-Open No. 1999-343128 describes a method of using a metal carbonate or the like instead of using a dangerous oxidant as a blowing agent, but the manufacturing method of the foamed glass other than this is the same as a conventional method.

Japanese Laid-Open Patent Publication No. 2000-026136 describes a foamed glass method of foaming at a low temperature of 750 to 900 DEG C using glass particles of two sizes and using silicon carbide as a blowing agent.

Japanese Patent Laid-Open No. 2000-072480 describes a method for producing superabsorbent bulk foam glass using waste glass, wherein the production method uses high temperature foaming using a conventional foaming agent.

U.S. Patent No. 3,951,362 describes a method of forming a high-strength foam glass at 850 to 950 캜 using a glass component rich in alumina components obtained from volcanic ash in Japan.

US Patent No. 3,975,174 describes a process for producing foamed glass by generating carbon dioxide at 950-1100 ° C. using a SnO ₂ and SiC mixture as blowing agent.

U.S. Patent No. 4,347,326 describes a method of foam molding at around 700 ° C using water glass as the main component and CaCO ₃ as the blowing agent.

U. S. Patent No. 5,384, 203 describes a method for producing a foamed glass in which a vaporized liquid is incorporated into a glass melted at a high temperature above a melting point, and then bubbled under reduced pressure.

As described above, the method for producing general foamed glass presented in the above-described domestic and foreign patents is characterized by mixing various glass components with a foaming agent and then foaming at a high temperature of 700 to 1200 ° C. Foaming agents such as calcium (CaCO ₃ ), dolomite (CaCO ₃ -MgCO ₃ ), carbon (C), silicon carbide (SiC), and calcium hydroxide phosphate compounds are required.

On the other hand, the glass hollow body is hollow hollow spherical glass particles, excellent flame retardancy and heat insulation, fine spherical particles are commonly used as additives of plastics.

Such glass hollow bodies are generally produced by forming fine droplets from a glassy aqueous solution containing an expanding agent such as urea, drying the formed droplets at high temperature, vitrifying them, and pyrolyzing the expanding agent (US Pat. No. 4,133,854). , 4,163,637, 4,247,799).

Another method is to gelatinize the glass-forming aqueous solution and then pulverize it into fine particles and foam at a high temperature of 1000 ° C. or more (US Pat. No. 4,336,338). The vitreous forming gel is then prepared by two methods. The first method is to add an appropriate amount of tetraethoxysilane, which is a raw material of silica, to the ethanol dissolved in alkali metal, followed by gelation by adding a 1: 1 mixture of ethanol and water, and the second method is tetraethoxysilane and ethanol. , Gelatinized by heating the mixture of water and hydrochloric acid to 70 ℃. The method has a disadvantage in that the process of making a gel is complicated and a high temperature foaming process is required.

Alternatively, US Pat. No. 4,983,550 discloses a glass frit by heating, dissolving and mixing various components to have a suitable chemical composition, followed by quenching with water to obtain a glass frit, which is then ground to a fine powder and foamed at high temperatures. It describes how to get it.

As another method of obtaining a glass hollow body, U.S. Patent No. 5,069,702 describes a method of adding a surfactant to a glass forming solution to disperse it into fine particles to obtain glass fine powder, and foaming it again.

U. S. Patent No. 6,531, 222 describes a method of vitrifying a glassy mixture containing foaming agent at 300-1500 DEG C and again wet grinding it to obtain fine particles and finally foaming them at high temperature.

The method of manufacturing a glass hollow body as described above and in the conventional domestic and foreign patents uses a method of making a composition containing a blowing agent into fine liquid particles or solid fine powder and then foaming at a high temperature. These methods also require a blowing agent separately and are foamed at high temperatures of around 1000 ° C.

The present invention is to solve the above problems, to provide an excellent foaming performance without using a foaming agent, and to provide a foaming glass composition showing a foaming performance at low temperatures and a method for producing a foamed glass precursor using the same.

In addition, to provide a use of the foamed glass precursor produced by the production method of the present invention.

In order to achieve the above object, the present invention provides a foamed glass composition comprising 20 to 50% by weight of alkali hydroxide and 50 to 80% by weight of silica.

The present invention also provides a method for producing a foamed glass precursor.

The present invention also provides a flame retardant and fire-extinguishing paint and paint comprising a foamed glass precursor.

Hereinafter, the present invention will be described in detail.

The present invention provides a foamed glass composition comprising 20 to 50% by weight of alkali hydroxide and 50 to 80% by weight of silica.

The alkali hydroxide dissolves silica and shows final foaming performance, preferably sodium hydroxide, potassium hydroxide or a mixture thereof. In the present invention, 20 to 50% by weight based on the foam glass composition is used, preferably 25 to 40% by weight. When the amount of alkali hydroxide is less than the above range, the silica does not dissolve well in water, and eventually, the glass foam required by the present invention does not occur, and when the above range is exceeded, the mechanical properties of the foam glass are weak and the foamed glass is Dissolves in water.

The silica is a basic material of the foamed glass composition, and in the form of powder, fumed silica, colloidal silica and silica powder having a particle diameter of 0.1 mm or less are applicable. For example, fumed silica having a small particle size and good alkali solubility is used.

The present invention includes boric acid (B (OH) ₃ ) to enhance the physical properties of the final foam glass. Foamed glass can be obtained without adding boric acid, but it has the effect of strengthening the thermal and mechanical properties of the foamed glass. In the present invention, 50 parts by weight or less is used with respect to the foamed glass composition. When the amount of use exceeds the above range, the effect of the alkaline component is canceled due to the weak acid boric acid, so that the glass foam required by the present invention does not occur.

The present invention also provides a method for producing the foamed glass precursor powder.

Specifically, mixing and dissolving a foamed glass composition comprising 20 to 50% by weight of alkali hydroxide and 50 to 80% by weight of silica (step 1);

Drying the obtained solution to obtain a solid (step 2);

Pulverizing and solidifying the solids (step 3); And

Drying and pulverizing the finely divided powder to obtain a foamed glass precursor powder (step 4) provides a method for producing a foamed glass precursor powder.

In addition, the foam glass composition of the step 1 is further used that includes 50 parts by weight or less of B (OH) ₃ with respect to the foam glass composition.

Hereinafter, each step will be described in detail.

In step 1, a solid made of alkali hydroxide and silica or a solid made of alkali hydroxide, silica and B (OH) ₃ is dissolved in water.

Specifically, an alkali aqueous solution is prepared by first dissolving alkali hydroxide in water. At this time, alkali hydroxide is used sodium hydroxide, potassium hydroxide or a mixture thereof, 20 to 50% by weight based on the foam glass composition. In addition, the amount of water is not particularly limited, but if the amount is too large, it takes a long time to dry in the drying step, and if too small, the silica cannot be dissolved. Therefore, the amount of water in the present invention is preferably 2-3 times the weight of the silica to be added.

In addition, when B (OH) ₃ is added to enhance the physical properties of the final foamed glass, B (OH) ₃ is dissolved in the aqueous alkali solution. In this case, the amount of B (OH) ₃ is used by 50 parts by weight based on the foam glass composition.

Silica is dissolved in the aqueous alkali solution thus obtained. Dissolution of silica is possible even at room temperature, but with a little heat, dissolution is faster. In the present invention, silica is used 50 to 80% by weight based on the foam glass composition. At this time, when the content of silica is low, the liquid becomes almost viscous, and the content of silica increases, indicating high viscosity. If the silica does not melt properly, the foaming performance will be reduced, so be careful.

In step 2, the solution obtained in step 1 is dried.

The drying is performed by gradually filling the solution in a thin drying dish and gradually increasing the temperature. At this time, the drying process and drying temperature are important for foaming performance. As the drying proceeds, the solution obtained in step 1 is gelled with increased viscosity, and when dried, the solution solidifies as it swells. In the initial stage of drying, drying is performed at 100 to 150 ° C, preferably at 110 to 120 ° C, so as to sufficiently solidify. The drying time depends on the amount of water used and the drying temperature, but preferably about 2 to 5 hours. As the dried solid material evaporates moisture, a large number of coarse bubbles of several centimeters to several millimeters are generated therein, resulting in swelling like bread. At this time, the dry state of the inside and the outside of the solid is different.

In step 3, the solid is ground and micronized.

The particle size of the pulverized powder has various sizes of 1 mm or less, and the particle distribution varies greatly depending on the degree of grinding. However, when pulverized too fine, care must be taken because the foaming performance is reduced during the subsequent drying step.

In step 4, the finely divided powder is dried and ground again.

Specifically, the finely divided powder is dried again at 100 to 150 ° C., preferably at 110 to 120 ° C. for 1 to 2 hours. At this time, the powder obtained inside the solid that was not swelled in the drying step 2 is swollen, and the solids dried sufficiently do not swell at all. This dried powder is again subjected to the grinding process by a dry mill again. If the drying step is not performed, the powder may be entangled with each other when the powder is stored at room temperature for a long time. In addition, when dried for too long or dried at a drying temperature exceeding the above range, the foaming performance of the powder particles after grinding is reduced.

The powder thus obtained can be used as foamed glass precursor.

The present invention also provides the use of the foamed glass precursor powder produced by the present invention.

The foam glass precursor is foamed at a temperature of 150 ℃ or more has the characteristic that one particle is foamed in the form of a plurality of glass droplets. Therefore, when the particles are foamed in an open space, the hollow spheres are foamed independently of each other, and the precursor powder is poured into a limited space such as a mold and foamed at a high temperature to obtain a foamed glass of a desired shape. In this case, the use of powder particles of a constant size has the advantage of obtaining foamed glass having pores of uniform size.

In addition, the foam glass precursor may be used as an inorganic additive for flame retardation of various paints and polymer resins. Specifically, the foamed glass precursor has a characteristic of foaming at a low temperature of 150 to 200 ℃, the configuration is simple and has the advantage of not using a special foaming agent, the organic coating material to which the foamed glass precursor is added wood or polymer material When applied to the surface of the, not only does not impart flame retardancy to the surface of the applied material, but when the surface temperature rises above 150 ℃ in the event of fire, it is naturally foamed to have a fire-extinguishing function and to form a heat-dissipating film of foam glass Indicates.

Hereinafter, the present invention will be described in detail by way of examples.

However, the following examples are merely to illustrate the present invention is not limited to the contents of the present invention.

Example 1 Preparation of Foamed Glass Precursor 1

200 g of NaOH, 100 g of KOH, and 100 g of B (OH) ₃ were dissolved in 1200 g of water to dissolve an alkali mixed solution, and 600 g of fumed silica was dissolved in the solution.

The solution thus obtained was poured thinly into a drying dish of about 1 cm in thickness, dried at 120 ° C. for 3 hours, and ground in a dry grinder for 1 minute. The pulverized powder was dried again at 120 ° C. for 2 hours, and further pulverized with a dry grinder for 1 minute.

The size of the powder particles thus obtained was mainly distributed between 1 and 0.1 mm, and the apparent density of the powder was 1.2 g / cm ³ . 1 is a photograph showing the foamed glass precursor powder obtained.

The obtained foamed glass precursor was foamed by heat treatment at 200 ° C. for 1 hour.

As a result, the volume increase due to external foaming was about 5 to 6 times, and the density was about 0.18 to 0.25 g / cm ³ . The powder particles usually appeared in the form of one large glass bubble and three or four small glass bubbles, and the size was about 10 to 1 mm in diameter.

When the powder particles were filled with 10 g in a 100 ml measuring cylinder and foamed at 200 ° C. for 1 hour, the upper foaming degree was relatively higher than the lower layer, and the lower layer was pressurized and the foaming degree was relatively low. The upper portion of the foamed glass hollow particles were separated and separated into pieces, but the lower portion of the foamed glass hollow particles were firmly combined to appear as one foamed glass body. Therefore, when 1g of powder particles were put in a 100 ml measuring cylinder and foamed at 200 ° C., the volume increase of the powder due to foaming was about 9 to 10 times and the apparent density was as low as 0.12 g / cm ³ . .

On the other hand, when the obtained foamed glass precursor was foamed by heat treatment at 400 ° C. for 1 hour, the volume increase due to the external foaming reached about 12 times (see FIG. 2). In FIG. 3, before and after foaming (left) and after foaming (right) of the 100 ml measuring cylinder before and after foaming are shown.

Therefore, it can be seen that the temperature and pressure affect the external requirements for foaming the glass foam precursor.

Example 2 Preparation of Foamed Glass Precursor 2

In order to investigate the presence or absence of foaming according to the amount of NaOH, KOH and B (OH) ₃ , a foamed glass precursor was prepared in a composition as shown in Table 1 below. Except for the composition, other manufacturing methods were performed in the same manner as in Example 1.

Composition ratio of each component (unit: g) water NaOH KOH B (OH) ₃ SiO ₂ (fumed) Foam 15 1.0 - - 5.0 X 15 1.6 - - 5.0 O 15 - 1.5 - 5.0 X 15 - 2.0 - 5.0 O 15 - - 2.0 5.0 X 15 0.5 0.5 - 5.0 X 15 0.5 1.0 - 5.0 △ 15 1.0 0.5 - 5.0 X 15 0.7 0.7 - 5.0 △ 15 1.0 1.0 - 5.0 O 15 1.0 1.0 1.0 5.0 X 15 1.0 1.0 0.5 5.0 O 15 0.5 1.1 0.5 5.0 X 15 0.5 0.5 - 5.0 X 15 0.8 0.8 0.3 5.0 O

 (O: Good foaming, △: poor foaming, X: impossible foaming)

Experimental Example 1 Molding Experiment

The foamed glass precursor prepared in Example 1 was poured into a mold to prepare a foamed glass, and then a molding experiment of the foamed glass was performed.

Specifically, 7 g of a sample (foam glass precursor of Example 1) was put into a cylindrical mold and heated at 400 ° C. for 1 hour to obtain a cylindrical foam glass body having a diameter of 25 mm and a height of 5 cm.

The foamed glass had a density of about 0.22 g / cm ³ and a compressive strength of about 3.3 kg / cm ² .

Experimental Example 2 Foaming Experiment

The foamed glass precursor prepared in Example 1 was mixed in a general paint and subjected to a foaming test. This experiment was carried out for the purpose of confirming that it could be used as an additive for polymer materials.

Specifically, the white enamel (Samhwa, SB-E-777) and the foamed glass precursor were mixed at a weight ratio of 4: 1 and coated on an aluminum plate at a thickness of 0.4 mm. After drying at room temperature for one day, after heating for 1 hour at 300 ℃ confirmed the apparent foaming properties.

As a result, the painted surface swelled due to foaming and increased to a thickness of about 3.2 mm. It was confirmed that the foamed glass precursor was swollen in the form of round particles.

As described above, the foamed glass precursor prepared by the present invention exhibits foaming performance without the use of a foaming agent, and in particular, exhibits foaming performance at low temperatures and can be used as a glass foam for heat dissipation and soundproofing, and can be used in addition to various paints and paints. Can be.

In particular, when used in addition to various paints and paints, not only does it impart flame retardancy to the surface of the applied material, but also foams in case of fire, and has an effect of forming a foamed glass heat radiation film having a fire extinguishing function.

1 is a photograph showing a foamed glass precursor powder of the present invention,

Figure 2 is a picture showing a foamed glass foamed glass foam precursor powder of the present invention at 400 ℃ for 1 hour,

3 is a photograph comparing the foamed glass precursor powder of the present invention before (left) and after foaming (right).

Claims (9)

A foamed glass composition comprising 20 to 50% by weight of alkali hydroxide, 50 to 80% by weight of silica and 50 parts by weight or less of B (OH) ₃ . The foamed glass composition according to claim 1, wherein the alkali hydroxide is sodium hydroxide, potassium hydroxide and mixtures thereof. The foamed glass composition according to claim 1, wherein the silica is fumed silica, colloidal silica or silica powder. delete delete Mixing and dissolving the foamed glass composition comprising 20 to 50% by weight of alkali hydroxide, 50 to 80% by weight of silica, and 50 parts by weight of B (OH) ₃ to water (step 1); Drying the obtained solution to obtain a solid (step 2); Pulverizing and solidifying the solids (step 3); And Drying the finely divided solids again to obtain a foamed glass precursor powder (step 4) method of producing a foamed glass precursor powder. delete The method of claim 6, wherein the drying of steps 2 and 4 is carried out at 100 to 150 ° C. A flame retardant and fire retardant paint comprising a foamed glass precursor powder prepared according to claim 6.