Cement foam for fire door, method of producing the same, and fire door

Abstract

A method for manufacturing a cement insulation material for a fire door comprising cement and an inorganic filler, wherein the cross-section of the cement insulation material comprises first pores with an average diameter of 50 μm to 500 μm and a compressive strength of 50 to 500 kPa, and a slurry of cement and an inorganic filler mixed with aqueous foam to form a foamed cement slurry; a step of drying the foamed cement slurry and then curing it in an autoclave; and a step of drying the cured material to manufacture a cement insulation material; wherein the cross-section of the cement insulation material comprises first pores with an average diameter of 200 μm to 400 μm and a compressive strength of 50 to 300 kPa, and a fire door comprising the same are provided.

Description

Technology Field

[0001] The present invention relates to a cement insulation material for fire doors, a method for manufacturing the same, and a fire door comprising the same. Background Technology

[0003] Typically, in order to prevent combustion and the spread of smoke within a building and to facilitate evacuation in the event of a fire, fire doors are installed in designated areas to automatically close those areas, thereby suppressing the spread of fire.

[0004] The above fire door refers to a door designed to withstand flames for a certain period of time, which is intended to provide time for evacuation in the event of a fire and to extend or block the time for the fire to spread. Although it is normally open to people, it is designed to prevent the penetration of flames in the event of a fire, making it a very important facility for minimizing the spread of flames and securing evacuation routes, and a structure that plays an important role in preventing fire damage.

[0005] Conventional fire doors are constructed with a structure consisting of steel panels filled with insulating materials such as paper honeycomb, urethane foam, glass wool, or mineral wool in the spaces between the steel plates. However, there is a problem in that fire safety is not ensured when using paper honeycomb or organic foams such as urethane foam. Furthermore, although glass wool or mineral wool are inorganic materials, there was a problem in that their strength was not sufficiently secured as they are fibrous insulating materials. Accordingly, using cement foam as the core material of fire doors could be considered; however, general cement insulating materials have high density and are heavy, which may limit their application. For example, they have disadvantages such as poor workability and difficulty in being used as interior doors. Moreover, due to their high density, they have high thermal conductivity, raising concerns that they may degrade the thermal insulation and heat shielding properties, which are the key performance characteristics of fire doors.

[0006] Accordingly, there is a continuing demand for cement insulation materials for fire doors that exhibit excellent fire resistance and heat resistance, while simultaneously demonstrating lightweight properties and excellent thermal insulation and strength. The problem to be solved

[0008] The objective of the present invention is to provide a cement insulation material for fire doors that exhibits excellent fire resistance and heat resistance, and simultaneously exhibits excellent thermal insulation and strength while being lightweight.

[0009] In addition, the objective of the present invention is to provide a method for manufacturing the cement insulation material for the fire door.

[0010] The objects of the present invention are not limited to those mentioned above, and other unmentioned objects and advantages of the present invention may be understood from the following description and will be more clearly understood by the embodiments of the present invention. Furthermore, it will be readily apparent that the objects and advantages of the present invention can be realized by the means and combinations thereof set forth in the claims. means of solving the problem

[0012] One embodiment according to the present invention can provide a cement insulation material for a fire door comprising cement and an inorganic filler, wherein the cross-section of the cement insulation material includes a first pore with an average diameter of 50 μm to 500 μm and has a compressive strength of 50 to 500 kPa.

[0013] In addition, another embodiment according to the present invention may provide a method for manufacturing a cement insulation material for a fire door, comprising the steps of: mixing a slurry of cement and an inorganic filler with aqueous foam to form a foamed cement slurry; drying the foamed cement slurry and then curing it in an autoclave; and drying the cured material to manufacture a cement insulation material, wherein the cross-section of the cement insulation material includes a first pore with an average diameter of 200 μm to 400 μm and has a compressive strength of 50 to 300 kPa.

[0014] In addition, another embodiment according to the present invention may provide a fire door comprising: a front plate; a rear plate corresponding to the front plate; and the cement insulation material between the front plate and the rear plate. Effects of the invention

[0016] The cement insulation material for fire doors according to the present invention exhibits excellent fire resistance and heat resistance, and can simultaneously exhibit excellent thermal insulation and strength while being lightweight.

[0017] The method for manufacturing a cement insulation material for a fire door according to the present invention can manufacture the cement insulation material for a fire door.

[0018] In addition to the effects described above, the specific effects of the present invention are described together with the specific details for implementing the invention below. Brief explanation of the drawing

[0020] FIG. 1 is a schematic diagram of a fire door including a cement insulation material for a fire door according to one embodiment of the present invention. FIG. 2 is a Scanning Electron Microscope (SEM) image of first pores distributed in the thickness direction cross-section of a cement insulation material for a fire door according to one embodiment of the present invention. Figure 3 shows the diameter distribution of pores included in a cross-section of a cement insulation material for a fire door according to one embodiment of the present invention. FIG. 4 is a Scanning Electron Microscope (SEM) image of second pores distributed in the thickness direction cross-section of a cement insulation material for a fire door according to one embodiment of the present invention. Figure 5 shows the heat resistance test results of Experimental Example 5. Specific details for implementing the invention

[0021] The aforementioned objectives, features, and advantages are described in detail below with reference to the attached drawings, thereby enabling those skilled in the art to easily implement the technical concept of the present invention. In describing the present invention, detailed descriptions of known technologies related to the present invention are omitted if it is determined that such descriptions would unnecessarily obscure the essence of the invention. Hereinafter, preferred embodiments according to the present invention will be described in detail with reference to the attached drawings. In the drawings, the same reference numerals are used to indicate the same or similar components.

[0022] Hereinafter, a cement insulation material for a fire door according to some embodiments of the present invention will be described.

[0024] One embodiment of the present invention provides a cement insulation material for a fire door comprising cement and an inorganic filler, wherein the cross-section of the cement insulation material for a fire door includes a first pore with an average diameter of 50 μm to 500 μm and a compressive strength of 50 to 500 kPa.

[0025] The above cement insulation for fire doors includes first pores with a small average diameter within the above range and exhibits excellent compressive strength within the above range, so it can be used for fire doors.

[0027] Specifically, cement insulation for fire doors contains pores along with cement and inorganic fillers. Conventional cement insulation forms pores using a post-foaming method, such as by using aluminum powder as a foaming agent and reacting it with hydrated lime to generate hydrogen gas. In this case, problems arise, such as the pore size of the cement insulation becoming very large, and density differences occurring due to variations in the pore distribution along the thickness direction. Furthermore, even in the case of pre-foaming, where foam is formed in advance and included in the composition of the cement insulation instead of the aforementioned post-foaming foaming agent, the pores of the resulting cement insulation exhibit an average diameter of several millimeters to tens of millimeters, resulting in high thermal conductivity and an inability to secure excellent thermal insulation performance.

[0028] The cement insulation material for fire doors according to the present invention comprises micro-sized first pores, exhibiting excellent non-combustibility, and can simultaneously exhibit excellent lightweighting, thermal insulation, and enhanced strength.

[0030] Specifically, the cement insulation material for fire doors may include first pores with an average diameter of 50 μm to 500 μm in the cross-section. The first pores can be measured in an SEM photograph taken by magnifying a cross-section of the cement insulation material for fire doors, cut perpendicularly to the surface in the thickness direction, at a magnification of approximately 30 to approximately 200. FIG. 2 shows the measurement of the diameter of the first pores using a photograph taken with a Scanning Electron Microscope (SEM) of a cross-section in the thickness direction of the cement insulation material according to Example 3 of the present invention. As shown in FIG. 2, the average diameter of the first pores refers to the average value obtained by measuring the longest diameter of each cell constituting the cross-section of the cement insulation material and dividing the sum of the diameters of the cells by the number of cells, and can be measured using imageJ from a photograph taken with a Scanning Electron Microscope (SEM). For example, the above insulation material is 200㎛ to 400㎛ or 300㎛ to 400 ㎛ It may include a first pore having an average diameter of .

[0031] Although the above-mentioned cement insulation for fire doors primarily contains open cells, it can simultaneously exhibit excellent lightweighting, thermal insulation, structural stability, and enhanced strength by including first pores of a small size within the above range. For example, if the average diameter of the first pores exceeds the above range, problems such as increased thermal conductivity or reduced strength may occur.

[0032] In addition, the cement insulation material for the fire door may contain at least 80% or at least 90% of first pores having a diameter of 100㎛ to 400㎛ among the first pores. And, it may contain at least 60% of first pores having a diameter of 100㎛ to 300㎛. The cement insulation material for the fire door may contain small pores as described above in a distribution within the above ranges.

[0033] The cement insulation material for the fire door described above can have a small average diameter within the above range while simultaneously having the above pore distribution. The cement insulation material for the fire door can maintain a stable pore structure even in a high-pressure manufacturing environment, thereby having pores within the above range, and can exhibit high strength while having low density.

[0034] The cement insulation material for fire doors described above may exhibit a porosity of 94 volume% to 99 volume%. By maintaining the porosity within the above range, the cement insulation material for fire doors can exhibit a high porosity as described above, while simultaneously exhibiting excellent thermal conductivity and compressive strength along with improved lightweighting.

[0036] The cement insulation material for the fire door described above may further include nano-sized second pores. The second pores are nano-sized and, together with the first pores, can more efficiently prevent an increase in thermal conductivity caused by the solid. The nano-sized second pores may be located on the cell wall of the first pores, and the second pores can be identified by photographing the cell wall of the pores with a Scanning Electron Microscope (SEM) at a magnification of approximately 10,000 to approximately 50,000. The second pores may be included in a ratio of approximately 1.5 to 4 volume% of the total pores contained in the cement insulation material for the fire door, that is, the total volume% of the first and second pores.

[0037] The above nano-sized second pores may have a diameter of 10 to 1,000 nm. The diameter of the above second pores was measured using a BET measuring device (ASAP 2020, manufacturer Micromeritics) for cement insulation for fire doors at a relative pressure of 10 -6 ~ The amount of nitrogen adsorbed can be measured at 77K up to atmospheric pressure.

[0038] The second pore of the cement insulation material for the fire door may contain 70% or more 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 relative to the total integrated area of ​​the pore distribution graph measured by nitrogen adsorption (N2 adsorption (at 77 K)). The second pore may contain 70% or more, 80% or more, or 90% or more of pores having a diameter of 10 nm to 400 nm. For example, it may contain 70% to 100%, 80% to 100%, or 90% to 100%.

[0040] The compressive strength of the cement insulation for the fire door is 50 to 500 kPa, and the density of the cement insulation for the fire door may be 60 kg / m3 to 140 kg / m3.

[0041] Cement insulation, a type of inorganic insulation, consists of cement and inorganic fillers. Due to its high density and heavy weight, it presents problems such as reduced workability and difficulty in utilizing it as an interior door. Consequently, there have been attempts to provide lightweight cement insulation by lowering its density. However, as the density of the cement insulation is reduced to achieve lighter weight, the compressive strength of the insulation decreases, leading to a problem where physical properties cannot be secured. Consequently, there are limitations on its use as a fire door.

[0042] On the other hand, the cement insulation material for fire doors according to the present invention can exhibit improved lightweight properties with low density while simultaneously exhibiting excellent compressive strength above a certain level. Furthermore, since it possesses excellent thermal insulation properties, it can also exhibit excellent heat insulation properties.

[0044] Specifically, the cement insulation for the fire door has a density of 60 kg / m3 to 140 kg / m3 or 60 kg / m3 to 120 kg / m3, exhibiting improved lightweight characteristics to improve constructability and allowing it to be used as an indoor fire door.

[0045] In addition, the cement insulation material for fire doors described above exhibits excellent lightweight properties as described above, while simultaneously exhibiting excellent compressive strength of 50 kPa to 500 kPa or 50 kPa to 400 kPa. Accordingly, it can be used as an insulation material included in fire doors that require a certain level of compressive strength.

[0046] The cement insulation material for fire doors described above can simultaneously have low density and high compressive strength. For example, the cement insulation material for fire doors may have a compressive strength of 50 kPa to 150 kPa at a density of 60 kg / m3 to 80 kg / m3, a compressive strength of 100 kPa to 250 kPa at a density greater than 80 kg / m3 to 100 kg / m3, and a compressive strength of 200 kPa to 300 kPa at a density greater than 100 kg / m3 to 120 kg / m3.

[0048] Generally, cement insulation consists of a solid form excluding voids, and since heat is easily transferred through solids, it may be difficult to ensure thermal insulation with cement insulation. The cement insulation for fire doors described above exhibits a low thermal conductivity of 33 to 37 mW / m·K, thereby demonstrating excellent thermal insulation. Accordingly, it can also exhibit excellent heat shielding properties.

[0049] The cement insulation material for the fire door described above may simultaneously have a first pore of the above range and a second pore of the above range, and while exhibiting excellent lightweighting with low density, it may simultaneously exhibit excellent thermal insulation, structural stability, and enhanced strength.

[0051] The above cement insulation for fire doors comprises cement. The cement may include one selected from the group consisting of Portland cement, blended cement, alumina cement, ultra-fast setting cement, low-alkali cement for GRC, and combinations thereof, but is not limited thereto.

[0052] The above cement may be included in the cement insulation for fire doors in an amount of 25% to 60% by weight, for example, 40% to 60% by weight.

[0054] The above cement insulation for fire doors includes an inorganic filler. The inorganic filler can increase bonding strength through the cement hardening mechanism when in contact with the cement. Additionally, the inorganic filler increases viscosity, contributes to the formation of pores in the insulation, and can affect the lightweighting of the insulation.

[0055] The above inorganic filler may include one selected from the group consisting of silica fume, fumed silica, bottom ash, silica sand, kaolin, silicate minerals, metal oxides, blast furnace slag, diatomite, dolomite, magnesite, bauxite, bentonite, clay, talc, zeolite, vermiculite, feldspar, ceriolite, atapulgite, and combinations thereof.

[0056] The inorganic filler may be spherical particles, but is not limited thereto. Furthermore, while the diameter of the inorganic filler is not particularly limited, it may be preferable for the average diameter of the inorganic filler to be 1 μm or less, for example, about 200 nm to 500 nm, in terms of bonding strength with cement and pore size. For example, the inorganic filler may include silica fume. The silica fume may be uniform spherical particles having a uniform size of about 1 μm or less, for example, a diameter of 200 nm to 300 nm. The insulating material may include the inorganic filler to control the pore size.

[0057] In addition, the cement insulation material for fire doors described above contains silica fume, and can provide superior effects more economically at a lower price compared to expensive inorganic fillers such as aerogel and wet silica.

[0058] In addition, the cement insulation for fire doors may not contain fly ash, and accordingly, strength can be improved more easily. In addition, the cement insulation for fire doors may not contain quicklime (CaO), and accordingly, strength and thermal insulation properties can be improved more easily. Furthermore, since quicklime (CaO) dissolves in water to exhibit alkaline properties and affects the pH of the composition, thereby affecting hardening reactivity, the cement insulation for fire doors may not contain Ca(OH)2. Accordingly, the cement insulation for fire doors can improve strength more easily.

[0060] The above inorganic filler may be mixed with the cement in a weight ratio of 3:7 to 7:3. For example, the inorganic filler and the cement may be mixed in a weight ratio of 5:5 to 7:3. By adjusting the content of the inorganic filler and cement within the above ranges, the pore size and physical properties of the cement insulation for fire doors can be easily controlled. For example, problems such as the collapse of the pore structure due to foam collapse or the cracking of the insulation surface, which leads to a decrease in compressive strength, can be prevented during the high-temperature and high-pressure manufacturing process. For example, if the content falls outside the above range and the cement content exceeds the above range, the viscosity decreases and the flowability of the mixture increases, causing the pore structure to collapse easily and drainage to occur. Furthermore, if the cement content is below the above range and the inorganic filler content exceeds the above range, dispersibility decreases, and additional mixing of water becomes necessary to resolve this. As a result, the concentration of the slurry decreases, and problems such as a decrease in compressive strength may occur as pores collapse or the surface of the insulation material cracks.

[0062] The above-mentioned insulating material may further include an organic binder. Accordingly, flexibility can be imparted to the insulating material. Specifically, the insulating material may include a polyurethane resin as the organic binder to lower thermal conductivity while allowing for easier control of physical properties. For example, the polyurethane resin may be formed from glycerol and isocyanate. The polyurethane resin may be formed using glycerol, which is easy to mix and disperse with water, thereby allowing for easier control of porosity and physical properties.

[0063] The above 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.

[0065] The cement insulation material for the fire door described above is formed by curing and drying a mixture containing aqueous foam in addition to the above material, wherein the foam may be formed by mixing a surfactant with water.

[0066] The above surfactant can increase the viscosity of the foam, and the surfactant may be included in the foam in an amount of 0.5% to 1.2% by weight or 1.0% to 1.2% by weight to maintain the pore structure more stably. For example, the surfactant may be included in the surfactant solution in an amount of 1.0% to 1.2% by weight.

[0067] The above surfactant may be a plant-based surfactant or an animal-based surfactant. Although not limited thereto, an animal-based surfactant may be more preferable in terms of stabilizing the pore structure during the curing time.

[0068] In addition, the cement insulation material for the fire door described above is formed by including the above-mentioned aqueous foam without including expensive aerogel, etc., thereby enabling superior physical properties to be imparted more economically.

[0070] Another embodiment of the present invention provides a method for manufacturing a cement insulation material for a fire door, comprising the steps of: mixing a slurry of cement and an inorganic filler with aqueous foam to form a foamed cement slurry; drying the foamed cement slurry and then curing it in an autoclave; and drying the cured material to manufacture a cement insulation material for a fire door, wherein the cross-section of the cement insulation material for a fire door includes a first pore with an average diameter of 200 μm to 400 μm, and the compressive strength is 50 to 300 kPa.

[0071] As described above, by the above manufacturing method, it is possible to manufacture the aforementioned cement insulation material for fire doors that exhibits specific pore characteristics, excellent fire resistance and heat resistance, and simultaneously exhibits excellent thermal insulation and strength while being lightweight.

[0073] First, the method for manufacturing the cement insulation material for the fire door described above includes the step of mixing a slurry of cement and inorganic filler with aqueous foam to form a foamed cement slurry.

[0074] The above cement slurry may further include an organic binder, and details regarding the cement, inorganic filler, organic binder, and aqueous foam are as described above.

[0075] In addition, the slurry may further include additives including a water reducer, a curing accelerator, a viscosity modifier, a pH modifier, a reinforcing agent, a stabilizer, a coating agent, a surface treatment agent, a filler, and combinations thereof. The slurry may not contain quicklime.

[0077] And, it includes the step of drying the foamed cement slurry and then curing it in an autoclave.

[0078] The above method for manufacturing cement insulation for fire doors includes a step of curing in an autoclave, which is a closed system, and can significantly increase the strength of the cement insulation for fire doors.

[0079] The cement included in the above slurry can form a tree branch shape as it hardens. Then, the inorganic filler and the foam are distributed and hardened between the tree branch-shaped cement to impart the aforementioned pore shape to the cement insulation material for fire doors, thereby simultaneously exhibiting excellent lightweighting, thermal insulation, and enhanced strength.

[0080] Specifically, the method includes the step of drying the foam cement slurry to form a cake and hardening the cake in an autoclave. The drying is a primary drying distinct from the drying of the hardened material, and, for example, the foam cement slurry can be dried at 20°C to 40°C and 90% to 95% humidity (RH) for 3 to 5 hours to form a cake.

[0082] In addition, the curing can be performed in an autoclave at 180°C to 200°C and 10 bar to 15 bar. Since the curing is performed in an autoclave with high pressure within the above range, if the density of the cake contained in the autoclave is too low or the structure of the pores contained in the cake is not stable, it may be difficult to obtain the desired cement insulation for fire doors. On the other hand, the cement insulation for fire doors is obtained by drying the aforementioned foam cement slurry and curing it in an autoclave, and the desired cement insulation for fire doors can be obtained by curing it in the autoclave despite the low density.

[0083] In addition, the curing can be performed for 3 to 7 hours. Accordingly, the cement insulation for fire doors can exhibit improved lightweighting with a very low density within the above range, while simultaneously exhibiting excellent thermal conductivity and compressive strength above a certain level within the above range. For example, the curing can be performed for 3 to 6 hours or 3 to 5 hours.

[0084] Specifically, if the temperature and pressure during curing in the autoclave are below the above range, there is a problem of insufficient strength development due to a slow curing reaction, and if they exceed the above range, there may be a problem of reduced strength due to excessive temperature.

[0085] In addition, if the curing time in the autoclave is less than the above range, there is a problem of insufficient strength, and if it exceeds the above range, there may be a problem of reduced strength and decreased productivity.

[0086] After that, the method includes the step of completely drying the cured material to manufacture a cement insulation material for fire doors. The drying can be performed by hot air drying at 80°C to 120°C.

[0088] Another embodiment of the present invention provides a fire door comprising, as shown in FIG. 1, a front plate; a rear plate corresponding to the front plate; and the aforementioned cement insulation between the front plate and the rear plate.

[0089] The above fire door can be used as a door leaf. The above front panel forms the front of the door leaf, and the above rear panel forms the rear of the door leaf.

[0090] The front and rear panels located on both sides of the above fire door impart mechanical properties to the fire door and can exhibit fire resistance when directly exposed to flames during a fire.

[0091] The above front plate or back plate may include one selected from the group consisting of galvanized steel sheet, electro-galvanized steel sheet, cold-rolled steel sheet, cold-rolled galvanized steel sheet, hot-rolled galvanized steel sheet, pickled steel sheet, high-strength steel sheet, and combinations thereof.

[0093] The above-described fire door may include the aforementioned cement insulation for fire doors inserted between the front and rear plates. Conventional insulation materials included in fire doors had a problem with insufficient heat resistance. Specifically, even if steel plates are present on both surfaces to exhibit flame resistance, heat is transferred into the interior of the fire door over time. Consequently, if the heat resistance of the insulation material contained inside is not ensured, it melts, making it impossible to secure insulation. The above-described cement insulation for fire doors exhibits excellent heat resistance, maintaining its shape even when exposed to high temperatures for a long time, thereby providing structural stability while maintaining insulation.

[0094] The details regarding the cement insulation material for the fire door are as described above. That is, the cement insulation material for the fire door exhibits fire resistance and heat resistance, and can simultaneously exhibit excellent thermal insulation and strength while being lightweight.

[0095] The thickness of the cement insulation for the fire door may be 40 mm to 100 mm, and the thickness of the cement insulation for the fire door may account for 97% to 98.8% of the total thickness of the fire door.

[0096] The cement insulation material for the fire door described above may be bonded and fixed to the inner surfaces of the front and rear panels using an adhesive. The adhesive is preferably, for example, a urethane-based or flame-retardant adhesive, but is not limited thereto.

[0098] (Example)

[0099] Example 1

[0100] Portland cement, silica fume with an average diameter of 200 nm, polyurethane resin, a water reducer, a curing accelerator, and water were mixed, and a slurry was prepared by stirring with a stirrer at 1000 rpm for 5 minutes. At this time, based on 100 parts by weight of the solid content of the slurry, 47 parts by weight of the cement was included, and 47 parts by weight of the silica fume was included so that the weight ratio of silica fume to cement was 5:5. Then, 3.6 parts by weight of polyurethane resin, 1.9 parts by weight of a curing accelerator, and 0.5 parts by weight of a water reducer were mixed.

[0101] Then, a surfactant solution made by mixing 1% by weight of an animal-derived surfactant (propump) with water was used to form an aqueous foam through a foam generator. Subsequently, the foam was mixed with the slurry to produce a foamed cement slurry. At this time, the weight of the foam was set to 150 parts by weight relative to 100 parts by weight of the slurry, and the total solid content concentration was set to 25% by weight.

[0102] The above foam cement slurry was poured into a mold measuring 20 cm x 20 cm x 3 cm and set to a height of 3 cm. It was then dried by storing it at 40°C and 90% RH for 3 hours to form a specimen (cake). Then, this specimen was cured in an autoclave at 180°C and 10 bar for 4 hours to produce a cured product. Afterward, the cured product was dried in an oven at 120°C to produce a cement insulation material for fire doors with a thickness of 3 cm.

[0103] A fire door was manufactured by including the above-mentioned cement insulation for the fire door between the front plate and the rear plate, which include an electro-galvanized steel plate.

[0105] Example 2

[0106] In Example 1, a cement insulation material for a fire door was manufactured in the same manner as in Example 1, except that the foam weight was 120 parts by weight relative to 100 parts by weight of the slurry and the total solid content concentration was 29% by weight.

[0108] Example 3

[0109] In Example 1, a cement insulation material for a fire door was manufactured in the same manner as in Example 1, except that the foam weight was 100 parts by weight relative to 100 parts by weight of the slurry and the total solid content concentration was 31% by weight.

[0111] Example 4

[0112] In Example 1, a cement insulation material for a fire door was manufactured in the same manner as in Example 1, except that the total content of the silica fume and cement was kept the same, but the weight ratio of the silica fume to cement was changed to 7:3.

[0114] Example 5

[0115] In Example 4, a cement insulation material for a fire door was manufactured in the same manner as in Example 4, except that the foam weight was 130 parts by weight relative to 100 parts by weight of the slurry and the total solid content concentration was 29% by weight.

[0117] Example 6

[0118] In Example 4, a cement insulation material for a fire door was manufactured in the same manner as in Example 4, except that the foam weight was 110 parts by weight relative to 100 parts by weight of the slurry and the total solid content concentration was 31% by weight.

[0120] Comparative Example 1

[0121] In Example 1, a cement insulation material for a fire door was manufactured in the same manner as in Example 1, except that the total content of the silica fume and cement was kept the same, but the weight ratio of the silica fume to cement was changed to 3:1.

[0123] Comparative Example 2

[0124] In Example 1, instead of including aqueous foam formed using a foam generator with a surfactant solution made by mixing 1 weight% of an animal surfactant (propump) with water, a cement insulation material for fire doors was manufactured by including 0.63 weight parts of aluminum powder based on 100 weight parts of slurry and reacting it with quicklime to generate hydrogen gas.

[0126] Comparative Example 3

[0127] We prepared glass wool panel insulation from a domestic company, K.

[0129] evaluation

[0130] Experimental Example 1: First pore size

[0131] A specimen was prepared by cutting the cement insulation material for fire doors of the examples and comparative examples into a 10 cm x 10 cm x 3 cm section. Then, the specimen was cut vertically in the thickness direction from the center point of the surface of the specimen. Then, the center of the cut surface was magnified 50 times and photographed using a Scanning Electron Microscope (SEM).

[0132] Using ImageJ, the diameter (longest diameter of the pore) of the first micro-sized pore forming the cell was measured in an arbitrary area of ​​4 mm (length, L) X 3 mm (width, W) in the cross-section. The average value was calculated, and the results are listed in Table 1 below. The diameter distribution of the first pore can be verified through a histogram obtained using the 'ImageJ' image processing program. For example, FIG. 3 is a histogram obtained using the 'ImageJ' image processing program showing the diameter distribution of the pores (i.e., the first pores) included in the cross-section of the cement insulation material according to Example 3 of the present invention.

[0134] Average diameter of the first pore (㎛) Proportion (%) of pores with a diameter of 100㎛ to 400㎛ among the first pores Example 1 395 80 Example 2 375 84 Example 3 324 89 Example 4 327 84 Example 5 304 87 Example 6 287 91 Comparative Example 1 518 48 Comparative Example 2 1,230 doesn't exist

[0135] As shown in Table 1 above, unlike the comparative example, it can be confirmed that the cement insulation material for fire doors of the example has a small first pore size. Also, in the case of Comparative Example 2, it was confirmed that pores with a diameter of 100㎛ to 400㎛ are not included, and pores with a diameter of 1㎜ or more are formed.

[0136] In addition, the cement insulation for fire doors of the example further includes nano-sized second pores. FIG. 4 is a Scanning Electron Microscope (SEM) image of the second pores distributed in the thickness direction cross-section of the cement insulation for fire doors according to the present invention. Specifically, a specimen was prepared by cutting the cement insulation for fire doors to a size of 3 cm x 3 cm x 3 cm, and the specimen was cut vertically in the thickness direction from the center point of the surface of the specimen. Then, the second pores were confirmed by magnifying the SEM at a magnification of 20,000, centering on the center of the cut surface. It can be seen that the second pores are located inside the cell wall of the first pores.

[0137] The diameter distribution of the second pore mentioned above was determined by preparing a specimen by cutting the cement insulation into 5 mm x 5 mm x 5 mm pieces, and using a BET measuring device (ASAP 2020, manufacturer Micromeritics) to measure the relative pressure 10 -6 This can be confirmed through a graph measuring the amount of nitrogen adsorption at 77K up to atmospheric pressure.

[0138] In addition, in the pore distribution graph measured by nitrogen adsorption (N2 adsorption (at 77 K)), the integrated area occupied by pores with a diameter of 10 nm to 400 nm relative to the total integrated area of ​​the graph can be measured to confirm that the cement insulation contains more than 70% of nano pores with a diameter of 10 nm to 400 nm.

[0140] Experimental Example 2: Thermal Conductivity (mW / m·k)

[0141] The cement insulation for fire doors of the examples and comparative examples was measured according to the KS L 9016 test method, and the results were converted into thermal conductivity (mW / m·k) and listed in Table 2 below.

[0143] Experimental Example 3: Density (kg / m³) 3 )

[0144] The density of the cement insulation for fire doors in the examples and comparative examples was measured, and the results are listed in Table 2 below.

[0146] Experimental Example 4: Compressive Strength (kPa)

[0147] The cement insulation for fire doors of the examples and comparative examples was prepared as five cubic specimens with a side length of 3 cm. Then, the compressive strength of the five specimens was measured using LLOYD Instruments AMETEK, and the average value is listed in Table 2 below.

[0149] Thermal conductivity (mW / m·K) Density (kg / m³) 3 ) Compressive strength Example 1 34.3 61.3 89 Example 2 34.9 82.6 134 Example 3 35.2 104.5 162 Example 4 34.9 64.8 114 Example 5 35.2 86.4 172 Example 6 35.8 112.5 240 Comparative Example 1 34.7 52.3 42 Comparative Example 2 54 171 283

[0150] As shown in Table 2 above, unlike the comparative example, it can be confirmed that the cement insulation material for fire doors of the example exhibits excellent thermal insulation with low thermal conductivity while exhibiting lightweight properties with low density, and simultaneously exhibits excellent compressive strength. Specifically, it can be confirmed that the cement insulation material for fire doors of the example has a compressive strength of 50 kPa to 150 kPa at a density of 60 kg / m3 to 80 kg / m3, a compressive strength of 100 kPa to 250 kPa at a density greater than 80 kg / m3 to 100 kg / m3, and a compressive strength of 200 kPa to 300 kPa at a density greater than 100 kg / m3 to 120 kg / m3. On the other hand, in the case of Comparative Example 1, although it exhibited excellent lightweight properties with a lower density than the example, it can be confirmed that the thermal conductivity increased and, in particular, the compressive strength decreased significantly. In addition, Comparative Example 2 involves forming pores using aluminum powder, and increasing the content of the aluminum powder to increase gas generation and expand the volume, thereby lowering the density. However, during this process, the structural stability of the insulation material was reduced, and as the aluminum powder expanded, bubbles floated upwards. Due to the reduced bubble stability, the pore structure collapsed during curing in an autoclave, resulting in the insulation material not being properly formed. Furthermore, it was confirmed that Comparative Example 2 has a high density, which limits weight reduction and also reduces thermal insulation performance.

[0152] Experimental Example 5: Heat resistance

[0153] A heat resistance test was performed on Example 1 and Comparative Example 3 using a furnace. The results are shown in FIG. 5. Specifically, the sample was placed inside a furnace at room temperature (20°C) and left for 30 minutes, after which its shape was observed. Then, the inside of the furnace was heated to 400°C at a rate of 10°C per minute and heat-treated to maintain the temperature at 400°C for 30 minutes, after which the sample was removed and its shape was observed. Then, the inside of the furnace was heated to 600°C at a rate of 10°C per minute and heat-treated to maintain the temperature at 600°C for 30 minutes, after which the sample was removed and its shape was observed.

[0155] As shown in Fig. 5, it can be seen that the structure of the glass wool insulation (b) of Comparative Example 3 collapses as the temperature rises. On the other hand, it can be seen that the cement insulation (a) of the Example maintains its shape almost consistently and exhibits excellent heat resistance.

[0157] Although the present invention has been described above with reference to the illustrated drawings, the present invention is not limited by the embodiments and drawings disclosed in this specification, and it is obvious that various modifications can be made by a person skilled in the art within the scope of the technical concept of the present invention. Furthermore, even if the effects of the configuration according to the present invention were not explicitly described while describing the embodiments of the present invention above, it is natural to acknowledge that the effects predictable by said configuration should also be recognized. Explanation of the symbols

[0159] 100: Fire door 10: Cement insulation for fire doors 20: Front panel, back panel

Claims

Claim 1 A cement insulation material comprising cement and an inorganic filler, wherein the cross-section of the cement insulation material comprises first pores with an average diameter of 50 μm to 500 μm, and has a compressive strength of 50 to 500 kPa, wherein the cement insulation material is formed by curing and drying a mixture comprising aqueous foam, wherein the foam is formed by mixing an animal surfactant with water, wherein the cross-section of the cement insulation material comprises at least 80% first pores with a diameter of 100 to 400 μm, wherein the cement insulation material further comprises second pores of nano size, wherein the second pores of the cement insulation material comprise at least 70% nano pores with a diameter of 10 nm to 400 nm, and wherein the cement insulation material does not contain CaO and Ca(OH)2. Claim 2 In claim 1, the density of the cement insulation material is 60 kg / m³ 3 Up to 140 kg / m² 3 Cement insulation for fireproof doors. Claim 3 delete Claim 4 Cement insulation for fire doors having a porosity of 94 volume% to 99 volume% in claim 1. Claim 5 delete Claim 6 A cement thermal insulation material for a fire door according to claim 1, wherein the inorganic filler comprises one selected from the group consisting of silica fume, fumed silica, bottom ash, silica sand, kaolin, silicate mineral, metal oxide, blast furnace slag, diatomite, dolomite, magnesite, bauxite, bentonite, clay, talc, zeolite, vermiculite, feldspar, ceriolite, ettapulgite, and combinations thereof. Claim 7 Cement insulation for fire doors according to claim 1, having a thermal conductivity of 33 to 37 mW / m·K. Claim 8 A method for manufacturing a cement insulation material for a fire door, comprising: a step of mixing a slurry of cement and an inorganic filler with aqueous foam to form a foamed cement slurry; a step of drying the foamed cement slurry and then curing it in an autoclave; and a step of drying the cured product to manufacture a cement insulation material; wherein the cross-section of the cement insulation material includes a first pore with an average diameter of 200 μm to 400 μm, and has a compressive strength of 50 to 300 kPa, the aqueous foam is formed by mixing an animal surfactant with water, the cement insulation material further includes a second pore of nano size, the second pore of the cement insulation material includes a nano pore with a diameter of 10 nm to 400 nm, and the slurry does not contain hydrated lime. Claim 9 A method for manufacturing cement insulation for fire doors according to claim 8, wherein the curing is performed at 180°C to 200°C and 10 bar to 15 bar. Claim 10 A method for manufacturing cement insulation for fire doors according to claim 8, wherein the curing is performed for 3 to 7 hours. Claim 11 A fire door comprising: a front plate; a rear plate corresponding to the front plate; and a cement insulation material according to any one of claims 1, 2, 4, 6 and 7 between the front plate and the rear plate. Claim 12 In claim 11, the front plate or rear plate comprises one selected from the group consisting of galvanized steel, electro-galvanized steel, cold-rolled steel, cold-rolled galvanized steel, hot-rolled galvanized steel, pickled steel, high-strength steel, and combinations thereof.

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