KR20240083064A - Cement foam and method for manufacturing therof - Google Patents

Abstract

It contains cement, an inorganic filler, and an organic binder, and the cross section of the insulation material is a slurry mixed with a cement insulation material containing first pores with an average diameter of 200㎛ to 500㎛, and cement, an inorganic filler, and an organic binder (foam). mixing with aqueous foam to form a foamed cement slurry; Curing the foamed cement slurry; and drying the cured product to manufacture a cement insulating material. A method for manufacturing a cement insulating material including a step is provided.

Description

Cement insulation and its manufacturing method {CEMENT FOAM AND METHOD FOR MANUFACTURING THEROF}

The present invention relates to cement insulation and its manufacturing method.

To prevent energy loss, various insulation materials have been developed and used in buildings. Such insulating materials largely include organic insulating materials and inorganic insulating materials. Organic insulating materials include Styrofoam and urethane foam, and inorganic insulating materials include glass wool, mineral wool, and rock wool.

Organic insulation is lighter than inorganic insulation and has excellent insulation properties, so it is widely used in buildings. However, organic insulation materials are known to be vulnerable to fire, and in particular, emit carbon monoxide during the combustion process, which is very harmful to the human body.

Accordingly, there is a tendency to use inorganic insulating materials to solve the above problems and ensure fire resistance, but inorganic insulating materials have problems such as being heavy, having poor insulating properties, and having poor heat resistance. For example, glass wool has poor heat resistance, such as melting at high temperatures, and mineral wool is heavy and has poor insulation properties.

Accordingly, there continues to be a demand for inorganic insulating materials that do not generate gases harmful to the human body in the event of a fire, exhibit excellent non-combustibility, and are lightweight while also exhibiting excellent insulating properties.

The purpose of the present invention is to provide an inorganic insulating material that exhibits excellent incombustibility and a cement insulating material that can simultaneously exhibit excellent insulating properties, crack resistance, and lightweight properties.

Another object of the present invention is to provide a method for manufacturing the cement insulation material.

The objects of the present invention are not limited to the objects mentioned above, and other objects and advantages of the present invention that are not mentioned can be understood by the following description and will be more clearly understood by the examples of the present invention. Additionally, it will be readily apparent that the objects and advantages of the present invention can be realized by the means and combinations thereof indicated in the patent claims.

One embodiment according to the present invention is a cement insulating material containing cement and an inorganic filler, and a cross section of the cement insulating material includes first pores with an average diameter of 200㎛ to 500㎛.

In addition, another embodiment according to the present invention includes mixing a slurry containing cement and an inorganic filler with foam to form a foamed cement slurry; Curing the foamed cement slurry; and drying the cured product to manufacture a cement insulating material, wherein the cross-section of the cement insulating material includes first pores having an average diameter of 200 ㎛ to 500 ㎛.

The cement insulating material according to the present invention is an inorganic insulating material that exhibits excellent incombustibility and can simultaneously exhibit excellent insulating properties, crack resistance, and lightweight properties.

Additionally, the method for manufacturing a cement insulating material according to the present invention can produce the cement insulating material.

In addition to the above-described effects, specific effects of the present invention are described below while explaining specific details for carrying out the invention.

Figure 1 is a photograph taken with an optical microscope (Dino-Lite pro) of a cross-section in the thickness direction of a cement insulation material according to an embodiment of the present invention.
Figure 2 shows the diameter distribution of the first pores included in the cross section of the cement insulating material according to Example 1 of the present invention.
Figure 3 shows the diameter distribution of nano-sized second pores included in the cement insulation material according to Example 1 of the present invention using N ₂ adsorption (at 77 K).
Figure 4 is a SEM (Scanning Electron Microscope) photograph of first pores distributed across the cross-section in the thickness direction of a cement insulation material according to an embodiment of the present invention.
Figure 5 is a SEM (Scanning Electron Microscope) photograph of second pores distributed in a cross-section in the thickness direction of a cement insulation material according to an embodiment of the present invention.

The above-described objects, features, and advantages will be described in detail later with reference to the attached drawings, so that those skilled in the art will be able to easily implement the technical idea of the present invention. In describing the present invention, if it is determined that a detailed description of known techniques related to the present invention may unnecessarily obscure the gist of the present invention, the detailed description will be omitted. Hereinafter, preferred embodiments according to the present invention will be described in detail with reference to the attached drawings. In the drawings, identical reference numerals are used to indicate identical or similar components.

Below, cement insulation materials according to some embodiments of the present invention will be described.

One embodiment of the present invention provides a cement insulating material containing cement and an inorganic filler, and the cross section of the cement insulating material includes first pores with an average diameter of 200㎛ to 500㎛.

In general, cement insulation, a type of inorganic insulation, includes cement, filler, and pores. Meanwhile, conventional cement insulators use aluminum powder as a foaming agent and form pores through a post-foaming method such as reacting with slaked lime to generate hydrogen gas to form pores. In this case, there is a problem in that the size of the pores included in the insulation material becomes very large, and the distribution of pores in the thickness direction changes, resulting in a density difference. In addition, even when foam is pre-formed and included in the composition for forming the cement insulating material instead of the post-foaming foaming agent, the pores of the cement insulating material formed therefrom have an average diameter of several millimeters to tens of millimeters, There was a problem in that excellent thermal insulation properties could not be secured due to high thermal conductivity.

By adjusting the average diameter of pores, the cement insulating material of the present invention can provide a cement insulating material that has excellent incombustibility, excellent insulation, crack resistance, and low-density, lightweight characteristics at the same time.

Specifically, the cement insulation material includes first pores with an average diameter of 200㎛ to 500㎛ in the cross section. The diameter of the first pore can be measured from an SEM photograph taken by magnifying a cross-section of the cement insulating material in the thickness direction perpendicular to the surface at a magnification of about 30 to about 200. Figure 4 shows the diameter of the first pores measured using a photograph of a cross-section in the thickness direction of a cement insulation material according to an embodiment of the present invention taken using a scanning electron microscope (SEM). As shown in Figure 4, the average diameter of the first pores is the longest diameter of each cell constituting the cross section of the cement insulation material, and the average value is the sum of the diameters of the cells divided by the number of cells. As such, it can be measured using imageJ from a photo taken using a SEM (Scanning Electron Microscope). For example, the insulating material may include first pores having an average diameter of 300 ㎛ to 500 ㎛ or 400 ㎛ to 500 ㎛.

Although the cement insulation mainly contains open pores (open cells), it can simultaneously exhibit excellent insulation, crack resistance, and low-density, lightweight characteristics by including first pores of a small size in the above range. For example, if the average diameter of the first pores exceeds the above range, problems such as increased thermal conductivity or cracks may occur.

In addition, the cement insulating material may have first pores having the average diameter, and may also include 60% or more or 70% or more of first pores having a diameter of 400 μm or less. Accordingly, thermal insulation can be further improved and crack resistance can be further improved.

The cement insulating material may have a porosity of 96 vol% to 99 vol%. The cement insulating material may have a density of 30 to 70 kg/m3, 35 to 60 kg/m3, or 35 to 55 kg/m3, and may be a lightweight inorganic insulating material. The cement insulation material is a low-density, lightweight insulation material in the above range and can improve constructability.

In addition, the cement insulator can maintain pores within the above range and exhibit excellent crack resistance while exhibiting a high porosity as described above.

In general, cement insulation is made of solid except for voids. In addition, since heat is easily transmitted through solids, it may not be easy to secure insulation properties with cement insulators.

The cement insulation material may further include nano-sized second pores. The second pore has a nano size and can more efficiently prevent an increase in thermal conductivity due to solids. The nano-sized second pore may be located in the cell wall of the first pore, and the second pore is scanned using a scanning electron microscope (SEM) at a magnification of about 10,000 to about 50,000. ) You can check by taking a picture. The second pores may be included in a ratio of about 1.5 to 4% by volume out of 100% by volume of the total pores included in the cement insulation material, that is, the total first pores and second pores.

The second nano-sized pore may have a diameter of 10 to 1,000 nm. As shown in Figure 3, the diameter of the second pore is measured by measuring the amount of nitrogen adsorption on the cement insulation material at 77K from a relative pressure of 10 ^-6 to normal pressure using a BET measuring device (ASAP 2020, manufacturer Micromeritics). You can.

The cement insulation material may contain more than 60% of nanopores with a diameter of 10 nm to 400 nm. This can be calculated as the integrated area occupied by pores with a diameter of 10 nm to 400 nm compared to the total integrated area of the graph in the pore distribution graph measured by nitrogen adsorption (at 77 K). The second pores may include 60% or more or 80% or more of pores having a diameter of 10 nm to 400 nm. For example, it may contain 60% to 100% or 80% to 100%.

In addition, the cement insulation material can exhibit excellent thermal insulation properties by exhibiting low thermal conductivity of 0.026 to 0.034 W/m·K or 0.028 to 0.0335 W/m·K.

The cement insulation material includes cement. The cement may include, but is not limited to, one selected from the group consisting of Portland cement, mixed cement, alumina cement, rapid setting cement, low alkali cement for GRC, and combinations thereof.

The cement may be included in the cement insulating material in an amount of 25% to 60% by weight, for example, 40% to 60% by weight.

The cement insulation material includes an inorganic filler. The bonding force of the inorganic filler may increase due to a cement hardening mechanism when it comes into contact with the cement. In addition, the inorganic filler increases viscosity, participates in the formation of pores in the insulation material, and can affect the weight reduction of the insulation material.

The inorganic fillers include silica fume, fumed silica, fly ash, bottom ash, silica sand, kaolin, silicate minerals, metal oxides, blast furnace slag, diatomaceous earth, dolomite, and magnesite. , bauxite, bentonite, clay, talc, zeolite, vermiculite, feldspar, seriolite, attapulgite, and combinations thereof.

The inorganic filler may be a spherical particle, but is not limited thereto. The diameter of the inorganic filler is not particularly limited, but from the viewpoint of bonding strength with cement and pore size, the average diameter of the inorganic filler is preferably 1 μm or less, for example, about 200 nm to 500 nm. can do. For example, the inorganic filler may include silica fume. The silica fume may have a uniform size of about 1 μm or less, for example, 200 nm to 300 nm in diameter, and may be particles of a uniform spherical shape. The insulation material can control the size of the pores by including the inorganic filler.

In addition, the insulating material contains silica fume and can exhibit superior economical effects at a lower price compared to expensive inorganic fillers such as airgel and wet silica.

The inorganic filler may be mixed with the cement at a weight ratio of 3:7 to 7:3. For example, the inorganic filler:cement may be mixed at a weight ratio of 5:5 to 7:3. The cement insulating material can control the pore size and physical properties of the cement insulating material by adjusting the content of the inorganic filler and cement. For example, problems such as the collapse of the pore structure as the foam collapses during the manufacturing process or the occurrence of cracks as the surface of the insulation material splits can be prevented. For example, if the cement content exceeds the above range, the viscosity decreases and the flowability of the mixture increases, the pore structure easily collapses, and a dehydration phenomenon may occur. Additionally, if the cement content is less than the above range and the inorganic filler content exceeds the above range, dispersibility deteriorates and additional mixing of water is required to solve this problem. As a result, the concentration of the slurry is lowered, and problems such as pores collapsing or the surface of the insulating material cracking may occur.

The insulation material may further include an organic binder. Accordingly, flexibility can be provided to the insulation material. Specifically, the insulation material contains polyurethane resin as an organic binder, so that physical properties can be more easily adjusted while lowering thermal conductivity. For example, the polyurethane resin may be formed of glycerol and isocyanate. The polyurethane resin may be formed using glycerol, which is easy to mix and disperse with water, and thus pores and physical properties can be more easily controlled.

The organic binder may be included in an amount of 1 to 20 parts by weight when the total content of cement and inorganic filler is 100 parts by weight.

The cement insulation material is formed by curing and drying a mixture containing foam (aqueous foam) in addition to the above materials, and the foam may be formed by mixing a surfactant with water.

The surfactant can increase the viscosity of the foam, and at this time, the surfactant is included in the foam in an amount of 1.0% to 1.2% by weight, so that the pore structure can be maintained more stably. For example, the surfactant may be included in the surfactant solution in an amount of 1.0% to 1.2% by weight.

The surfactant may be a vegetable surfactant or an animal surfactant. Although not limited to this, animal-based surfactants may be more preferable in terms of stabilizing the pore structure during the curing time.

In addition, the cement insulation material does not contain expensive airgel, but is formed by including the foam (aqueous foam), and can provide excellent physical properties more economically.

Another embodiment of the present invention includes mixing a slurry containing cement and an inorganic filler with aqueous foam to form a foamed cement slurry; curing the foam cement slurry; and drying the cured material to produce a cement insulating material.

By the above manufacturing method, the above-described cement insulating material can be manufactured that exhibits the above-described pore characteristics, excellent incombustibility, excellent insulation, crack resistance, and low-density, lightweight characteristics at the same time.

First, the method of manufacturing the cement insulator includes mixing a slurry containing cement and an inorganic filler with aqueous foam to form a foamed cement slurry.

The cement slurry may further include an organic binder, and details regarding cement, inorganic filler, organic binder, and foam (aqueous foam) are as described above.

In addition, the slurry may further include additives including a water reducer, a curing accelerator, a viscosity regulator, a pH regulator, a reinforcing agent, a stabilizer, a coating agent, a surface treatment agent, a filler, and a combination thereof.

And, it includes the step of hardening the foam cement slurry. The cement contained in the slurry may form a tree branch shape as it hardens. In addition, the inorganic filler and the foam are distributed between the tree branch-shaped cement and hardened, thereby allowing the cement insulating material to have the pore shape described above.

In order for the cement insulation material to have the above-described pore structure and simultaneously exhibit the desired physical properties, it is important to cure it at an appropriate temperature and humidity. For example, if appropriate curing conditions are not met, pores may burst during the curing process and merge with surrounding pores, increasing the size of the pores or easily causing the pores to disappear.

Accordingly, the cement insulator prevents the above problems from occurring by controlling the curing stage, etc., and the cement insulator manufactured thereby has the above-described pore structure and can simultaneously exhibit the desired physical properties.

Cement insulation materials require moisture when curing, and the cured structure can be affected depending on the state of moisture during curing time.

Specifically, the curing may be performed at a temperature of 30°C to 60°C and a humidity of 70% to 90%. If the temperature at the time of curing is below the above range, the curing reaction may not sufficiently occur and expression may be insufficient. Accordingly, there may be a problem in that the average diameter of the first pores increases and the proportion of pores with a diameter of 400 ㎛ or less among the first pores decreases. In addition, when the curing temperature exceeds the above range, the average diameter of the first pores becomes too large due to excessively rapid evaporation of moisture, the ratio of pores with a diameter of 400 ㎛ or less among the first pores becomes too low, and dimensional changes and cracks occur. There may be problems such as In addition, if the humidity during curing is below the above range, moisture evaporates quickly, which may cause a problem of insufficient moisture required during curing and shrinkage due to rapid evaporation. Accordingly, there may be a problem in that the average diameter of the first pores increases and the proportion of pores with a diameter of 400 ㎛ or less among the first pores decreases. In addition, if the above range is exceeded, there may be problems such as evaporation being delayed, hardening taking too long, and development being delayed, causing deformation of the pore structure.

In addition, the curing may be performed until the moisture content of the cement insulating material, which is the cured product, is 5% by weight to 30% by weight. Accordingly, the structure of the cement insulator can be adjusted and the moisture content can be adjusted in the drying process, which is a post-process.

The method of manufacturing the cement insulator may further include drying the foam cement slurry to form a cake before curing the foam cement slurry. For example, the step of drying the foam cement slurry at 35°C to 40°C and 90% to 95% humidity (RH) for 3 to 5 hours to form a cake may be further included.

Thereafter, it includes the step of completely drying the cured product to manufacture a cement insulation material. The drying can be performed by hot air drying at 80°C to 120°C.

(Example)

Example 1

Portland cement, silica fume with an average diameter of 200 nm, polyurethane resin, water reducing agent, curing accelerator, and water were mixed and stirred at 1000 rpm for 5 minutes using a stirrer to prepare a slurry. At this time, based on 100 parts by weight of the slurry solid content, 44 parts by weight of the cement was included, and 44 parts by weight of silica fume was included so that the weight ratio of silica fume:cement was 5:5. Then, 10 parts by weight of polyurethane resin, 1.5 parts by weight of curing accelerator, and 0.5 parts by weight of water reducing agent were mixed.

Then, a surfactant solution prepared by mixing 1% by weight of animal surfactant (propump) with water was used to form aqueous foam through a foam generator. Thereafter, the foam was mixed with the slurry to prepare a foamed cement slurry. At this time, the foam weight was 150 parts by weight compared to 100 parts by weight of the slurry, and the total solid concentration was 25% by weight.

The foam cement slurry was poured into a mold measuring 20 This specimen was cured at a temperature of 50°C and humidity of 80% while removing moisture until the moisture content reached 20% by weight to prepare a cured product. Afterwards, the cured product was dried in an oven at 120°C to produce a cement insulation material with a thickness of 3 cm.

Example 2

In Example 1, a cement insulation material was manufactured in the same manner as in Example 1, except that the total content of silica fume and cement was the same, but the weight ratio of silica fume:cement was changed to 7:3. did.

Comparative Example 1

In Example 1, a specimen was formed from the foam cement slurry using a mold. Then, the specimen was cured at 23°C and 50% humidity while removing moisture until the moisture content reached 20% by weight, and the cured product was dried in an oven at 120°C to prepare a cement insulation material with a thickness of 3cm.

Comparative Example 2

In Example 1, a specimen was formed from the foam cement slurry using a mold. Then, the specimen was immediately dried in an oven at 120°C to produce a cement insulation material with a thickness of 3 cm.

evaluation

Experimental Example 1: Average pore size

Samples were prepared by cutting the cement insulation materials of Examples and Comparative Examples into 10cm x 10cm x 3cm. Then, the specimen was cut vertically in the thickness direction at the center point of the surface. Then, the center portion of the cut surface was enlarged and photographed at 50x magnification using a SEM (Scanning Electron Microscope).

Using ImageJ, the diameter (longest diameter of the pore) of the micro-sized first pore forming the cell was measured in a random 4 mm (length, L) x 3 mm (width, W) area of the cross section. Then, the average value was calculated, and the results are listed in Table 1 below. The diameter distribution of the first pore can be confirmed through a histogram obtained using the ‘ImageJ’ image processing program. For example, Figure 2 is a histogram of the diameter distribution of pores (i.e., first pores) included in the cross section of the cement insulation manufactured according to Example 1 using the 'ImageJ' image processing program.

1st qigong
Average diameter (㎛) Among the first pores, the ratio (%) of pores with a diameter of 400㎛ or less Example 1 453 72 Example 2 413 76 Comparative Example 1 715 41 Comparative Example 2 642 37

As shown in Table 1, unlike the comparative example, it can be seen that the cement insulation material of the example has a small first pore size.

In addition, the cement insulation material of the example further includes nano-sized second pores. Figure 5 is a SEM (Scanning Electron Microscope) photograph of the second pores distributed in the cross-section of the cement insulation material of the present invention in the thickness direction. Specifically, a specimen was prepared by cutting the cement insulation material into 3cm x 3cm x 3cm, and the specimen was cut vertically in the thickness direction at the center point of the surface. Then, the second pore was confirmed by enlarging the center of the cut surface at a magnification of 20,000 using a SEM (Scanning Electron Microscope). It can be seen that the second pore is located inside the cell wall of the first pore.

The diameter distribution of the second pore was determined by cutting the cement insulation material into 5 mm x 5 mm x 5 mm to prepare a specimen, and measuring the specimen at a relative pressure of 10 ^-6 ~ This can be confirmed by measuring the amount of nitrogen adsorption at 77K up to normal pressure. For example, Figure 3 shows a specimen measuring ⁵ mm This is a graph measuring the amount of nitrogen adsorption at 77K. As shown in the graph, it can be seen that the embodiment of the present invention includes nano-sized second pores.

In addition, it can be seen that the cement insulation material contains more than 60% of the second nano-sized pores with nanopores having a diameter of 10 nm to 400 nm. Specifically, in the pore distribution graph measured by nitrogen adsorption (at 77 K) in FIG. 3, the integrated area occupied by pores with a diameter of 10 nm to 400 nm is 60% or more compared to the total integrated area of the graph. You can check that.

Experimental Example 2: Thermal conductivity (W/m·k)

The cement insulation materials of Examples and Comparative Examples were measured according to the KS L 9016 test method, and the results were converted to thermal conductivity (W/m·k) and listed in Table 2 below.

Experimental Example 3: Density (kg/m ³ ) and whether cracks occur

The density of the cement insulators of Examples and Comparative Examples was measured, the surface of the manufactured cement insulator was visually checked for cracks, and the results are shown in Table 2 below.

Thermal conductivity (W/m·K) Density (kg/m ³ ) Cracked or not Example 1 0.0323 42.6 no cracks Example 2 0.0334 52.5 no cracks Comparative Example 1 0.0364 77.0 no cracks Comparative Example 2 0.0339 51.3 crack occurs

As shown in Table 2, unlike the comparative example, it can be confirmed that the cement insulating material of the example having a small first pore size exhibits lightness with a low density, low thermal conductivity, and does not generate cracks. In the case of Comparative Example 2, which was dried without a curing process, the curing reaction progressed slightly and a dense structure was not formed, so the thermal conductivity was measured to be low, but the shape of the insulating material was not formed well, so it was manufactured in a defective state.

As described above, the present invention has been described with reference to the illustrative drawings, but the present invention is not limited to the embodiments and drawings disclosed herein, and various modifications may be made by those skilled in the art within the scope of the technical idea of the present invention. It is obvious that transformation can occur. In addition, although the operational effects according to the configuration of the present invention were not explicitly described and explained while explaining the embodiments of the present invention above, it is natural that the predictable effects due to the configuration should also be recognized.

Claims (11)

It is a cement insulation material containing cement and inorganic filler,
The cross section of the cement insulation material includes first pores with an average diameter of 200㎛ to 500㎛.
Cement insulation.
According to paragraph 1,
The first pores include more than 60% of pores with a diameter of 400㎛ or less.
Cement insulation.
According to paragraph 1,
having a porosity of 96% to 99% by volume.
Cement insulation.
According to paragraph 1,
The cement insulation further includes nano-sized second pores,
The nano-sized second pores contain more than 60% of nanopores with a diameter of 10 nm to 400 nm.
Cement insulation.
According to paragraph 1,
The inorganic fillers include silica fume, fumed silica, fly ash, bottom ash, silica sand, kaolin, silicate minerals, metal oxides, blast furnace slag, diatomaceous earth, dolomite, and magnesite. , bauxite, bentonite, clay, talc, zeolite, vermiculite, feldspar, seriolite, attapulgite, and combinations thereof.
Cement insulation.
According to paragraph 1,
The cement insulation further includes an organic binder,
The organic binder is polyurethane resin.
Cement insulation.
According to paragraph 1,
Thermal conductivity is 0.026~0.034 W/m·K
Cement insulation.
According to paragraph 1,
With a density between 30 kg/m3 and 70 kg/m3
Cement insulation.
Mixing a slurry containing cement and an inorganic filler with aqueous foam to form a foamed cement slurry;
Curing the foamed cement slurry; and
Comprising: manufacturing a cement insulation material by drying the cured product,
The cross section of the cement insulation material includes first pores with an average diameter of 200㎛ to 500㎛.
Manufacturing method of cement insulation.
According to clause 9,
The curing is performed at a temperature of 30°C to 60°C and humidity of 70% to 90%.
Manufacturing method of cement insulation.
According to clause 9,
The curing is performed until the moisture content of the cured product is 5% by weight to 30% by weight.
Manufacturing method of cement insulation.