JP6985124B2 - Safe and its manufacturing method - Google Patents

Description

The present invention relates to a safe and a method for manufacturing the safe.

Conventionally, safes with excellent fire resistance and heat insulation that can prevent documents and valuables stored in safes from being easily burned or made worthless due to flames or high temperatures caused by fires, etc. Proposed.
In Patent Document 1, as a wall body in a fireproof safe or the like, a foam concrete wall material is stretched on either the inside or the outside on the low temperature side, and inside a sealed box made of a metal plate arranged on the side exposed to high temperature. Fireproof insulation walls characterized by being filled with ordinary Portland cement powder are described.
Further, in Patent Document 2, a plate-shaped heat insulating material made of a lightweight heat insulating material such as calcium silicate is provided in a space between the outer surface plate and the inner surface plate of a wall body in a refractory furniture such as a safe or a fireproof cabinet. Described is a heat insulating structure of a refractory fixture, which is characterized in that it is covered with foil and arranged, and concrete is filled without gaps.

Japanese Unexamined Patent Publication No. 6-235277 Japanese Unexamined Patent Publication No. 7-12738

In addition to excellent fire resistance and heat insulation, safes are required to have excellent crime prevention properties (strong against impacts from hammers, tools, etc., and difficult to drill holes with drills, etc.).
Therefore, an object of the present invention is to provide a safe having excellent crime prevention, fire resistance and heat insulating properties.

As a result of diligent studies to solve the above problems, the present inventor has one or both of the safe body and the safe door between the outer surface plate portion, the inner surface plate portion, and the outer surface plate portion and the inner surface plate portion. Includes a metal plate structure with an intervening containment space, a cementitious hardened material housed in a portion of the containment space of the metal plate structure, and a heat insulating material housed in the rest of the containment space of the metal plate structure. The hardened cementous material is cement, silica fume with BET specific surface area of 15 to 25 m ² / g, inorganic powder with 50% volume cumulative particle size of 0.8 to 5 μm, aggregate A with maximum particle size of 1.2 mm or less, According to the safe, which is a cured product of a cement composition containing a high-performance water reducing agent, a defoaming agent, a specific metal fiber, an organic fiber and water, and the composition of a specific material is within a specific numerical range. The present invention has been completed by finding that the object can be achieved.

That is, the present invention provides the following [1] to [7].
[1] A safe having a vault body and a vault door, wherein either or both of the vault body and the vault door forms an outer surface plate portion for forming an outer surface of the vault and an inner surface of the vault. A metal plate structure having an inner surface plate portion for the purpose and a storage space interposed between the outer surface plate portion and the inner surface plate portion, and a cement material accommodated in a part of the accommodation space of the metal plate structure. The hardened material contains a heat insulating material housed in the rest of the storage space of the metal plate structure, and the cementic hardened body is cement, ^{silica fumes having a BET specific surface area of 15 to 25 m 2} / g, and 50% volume accumulation. Inorganic powder with a particle size of 0.8 to 5 μm, aggregate A with a maximum particle size of 1.2 mm or less, a high-performance water reducing agent, a defoaming agent, a diameter of 0.01 to 1.0 mm and a length of 2 to 2 It is a cured product of a cement composition containing 30 mm of metal fibers, organic fibers and water, and the ratio of the cement to the total amount of 100% by volume of the cement, the silica fumes and the inorganic powder is 55 to 65% by volume, and the silica fumes. The ratio of the metal fibers in the cement composition is more than 3.0% by volume and 4.5% by volume or less. A safe characterized by being.
[2] The above-mentioned [1], wherein the organic fiber is a polypropylene fiber having a diameter of 0.010 to 0.020 mm, a length of 4 to 8 mm, and an aspect ratio (fiber length / fiber diameter) of 300 to 470. Safe.
[3] The safe according to the above [1] or [2], wherein the hardened cementum has a compressive strength of 300 N / mm ^{2 or more.}
[4] The safe according to the above [1] or [2], wherein the cement composition contains an aggregate B having a maximum particle size of more than 1.2 mm and 13 mm or less.
[5] The safe according to the above [4], wherein the hardened cementum has a compressive strength of 270 N / mm ^{2 or more.}

[6] The method for manufacturing the safe according to any one of the above [1] to [5], wherein the cement composition is cast into a mold to obtain an uncured molded product. The step, the room temperature curing step of sealing or aerial curing the uncured molded product at 10 to 40 ° C. for 24 hours or more to obtain a cured molded product, and 70 ° C. or higher for the cured molded product. A heat curing step of obtaining a cured product after heat curing by performing one or both of steam curing or hot water curing at a temperature of less than 100 ° C. for 6 hours or more and autoclave curing at 100 to 200 ° C. for 1 hour or more, and the above heating. A high-temperature heating step of heating the cured product after curing at 150 to 200 ° C. for 24 hours or more (excluding heating by autoclave curing) to obtain a cement-like cured product, and the cement-cured product and the metal. A method for manufacturing a safe, comprising: an assembly step of manufacturing the safe using the plate structure and the heat insulating material.
[7] The method for manufacturing a safe according to the above [6], which comprises a water absorption step of causing the cured molded product to absorb water between the normal temperature curing step and the heat curing step.
[8] The method for manufacturing a safe according to the above [6], wherein the metal plate structure is used as at least a part of the formwork.

The safe of the present invention has high compressive strength and bending strength (for example, compressive strength: 270 N / mm ² or more, bending strength: 45 N / mm ² or more), and is excellent in fracture resistance (impact resistance) and fire resistance. Because it uses a hardened cement, it has excellent crime prevention and fire resistance. Further, since the safe of the present invention uses a heat insulating material, it has excellent heat insulating properties.

FIG. 3 is a cross-sectional view showing an example of a safe of the present invention in a substantially central portion of a safe door, in a state of being vertically cut in a direction perpendicular to the surface of the door. The figure which shows the flat plate specimen of the impact resistance test using the steel weight ((a): the front view of the flat plate specimen, (b): the side view of the flat plate specimen; the unit of a numerical value is mm). Is.

The safe of the present invention is a safe having a safe body and a safe door, and one or both of the safe body and the safe door forms an outer surface plate portion for forming an outer surface of the safe and an inner surface of the safe. A metal plate structure having an inner surface plate portion and an accommodation space interposed between the outer surface plate portion and the inner surface plate portion, a cementic hardened body accommodated in a part of the accommodation space of the metal plate structure, and a metal. The cement-like hardened body contains a heat insulating material accommodated in the rest of the accommodation space of the plate structure, and the cement is ^{a silica fume having a BET specific surface area of 15 to 25 m 2} / g (hereinafter, may be abbreviated as "silica fume"). , 50% volume Inorganic powder having a cumulative particle size of 0.8 to 5 μm (hereinafter, may be abbreviated as “inorganic powder”), aggregate A having a maximum particle size of 1.2 mm or less (hereinafter, “aggregate A”). ), High-performance water reducing agent, defoaming agent, curing of cement composition containing metal fiber, organic fiber and water having a diameter of 0.01 to 1.0 mm and a length of 2 to 30 mm. It is a body, and the ratio of cement is 55 to 65% by volume, the ratio of silica fume is 5 to 25% by volume, and the ratio of inorganic powder is 15 to 35% by volume in the total amount of 100% by volume of cement, silica fumes and inorganic powder. The proportion of metal fibers in the cement composition is more than 3.0% by volume and 4.5% by volume or less.
Hereinafter, the cement composition used in the present invention will be described in detail.

The type of cement is not particularly limited, and for example, various Portland cements such as ordinary Portland cement, early-strength Portland cement, ultra-early-strength Portland cement, moderate heat Portland cement, sulfate-resistant Portland cement, and low heat Portland cement can be used. Can be used.
Above all, from the viewpoint of improving the fluidity of the cement composition, it is preferable to use moderate heat Portland cement or low heat Portland cement.

The BET specific surface area of silica fume is 15 to 25 m ² / g, preferably 17 to 23 m ² / g, and particularly preferably 18 to 22 m ² / g. When the specific surface area is ^{less than 15 m 2} / g, the strength (compressive strength and bending strength) and fracture resistance of the hardened cementum are lowered. When the specific surface area ^{exceeds 25 m 2} / g, the fluidity of the cement composition decreases.

Inorganic powders with a 50% volume cumulative particle size of 0.8 to 5 μm include, for example, quartz powder (silica powder), volcanic ash, and fly ash (classified or crushed), slag powder, limestone powder, and pebbles powder. Examples thereof include mulite powder, alumina powder, silica sol, carbide powder, and nitride powder.
These may be used individually by 1 type and may be used in combination of 2 or more type.
Above all, it is preferable to use quartz powder or fly ash from the viewpoint of improving the fluidity of the cement composition and increasing the strength (compressive strength and bending strength) and fracture resistance of the hardened cementum.
In the present specification, it is assumed that the inorganic powder having a 50% cumulative particle size of 0.8 to 5 μm does not contain cement.

The 50% volume cumulative particle size of the inorganic powder is 0.8 to 5 μm, preferably 1 to 4 μm, more preferably 1.1 to 3.5 μm, and particularly preferably 1.2 μm or more and less than 3 μm. When the particle size is less than 0.8 μm, the fluidity of the cement composition decreases. When the particle size exceeds 5 μm, the strength (compressive strength and bending strength) and fracture resistance of the hardened cementum are lowered.
The 50% volume cumulative particle size of the inorganic powder can be determined using a commercially available particle size distribution measuring device (for example, manufactured by Nikkiso Co., Ltd., product name "Microtrack HRA Model 9320-X100").
Specifically, a cumulative particle size curve can be created using a particle size distribution measuring device, and a 50% volume cumulative particle size can be obtained from the cumulative particle size curve. ^{At this time, 0.06 g of the sample was added to 20 cm 3 of} ethanol, which is a solvent for dispersing the sample, and an ultrasonic disperser (for example, manufactured by Nissei Tokyo Office, product name "US300") was used for 90 seconds. Measure the ultrasonic dispersion.

The maximum particle size of the inorganic powder is preferably 15 μm or less, more preferably 14 μm or less, and particularly preferably 13 μm or less, from the viewpoint of increasing the strength (compressive strength and bending strength) and fracture resistance of the hardened cementum. ..
The 95% volume cumulative particle size of the inorganic powder is preferably 8 μm or less, more preferably 7 μm or less, and particularly preferably 6 μm, from the viewpoint of increasing the strength (compressive strength and bending strength) and fracture resistance of the cementitious cured product. It is as follows.

As the inorganic powder, _{one containing SiO 2} as a main component (for example, quartz powder) is preferable. _{When the content of SiO 2} in the inorganic powder is preferably 50% by mass or more, more preferably 60% by mass or more, and particularly preferably 70% by mass or more, the strength (compressive strength and bending strength) of the cementitious cured product. And break resistance becomes higher.

In the cement composition, the ratio of cement to 100% by volume of the total amount of cement, silica fume and inorganic powder is 55 to 65% by volume, preferably 57 to 63% by volume. When the ratio is less than 55% by volume, the strength (compressive strength and bending strength) and fracture resistance of the hardened cementum are lowered. When the ratio exceeds 65% by volume, the fluidity of the cement composition decreases.
The ratio of silica fume to 100% by volume of the total amount of cement, silica fume and inorganic powder is 5 to 25% by volume, preferably 7 to 23% by volume. When the ratio is less than 5% by volume, the strength (compressive strength and bending strength) and fracture resistance of the hardened cementum are lowered. When the ratio exceeds 25% by volume, the fluidity of the cement composition decreases.
The ratio of the inorganic powder to 100% by volume of the total amount of cement, silica fume and the inorganic powder is 15 to 35% by volume, preferably 17 to 33% by volume. When the ratio is less than 15% by volume, the strength (compressive strength and bending strength) and fracture resistance of the hardened cementum are lowered. When the ratio exceeds 35% by volume, the fluidity of the cement composition decreases.

The aggregate A includes river sand, land sand, sea sand, crushed sand, silica sand, natural emery sand, artificial fine aggregate (for example, slag fine aggregate, fired fine aggregate obtained by firing fly ash, etc., and artificial fine aggregate. Examples thereof include (artificial) emery sand, coarsely pulverized products of alumina or carbides (for example, silicon carbide, boron carbide, etc.), recycled fine aggregates, or mixtures thereof.
The maximum particle size of the aggregate A is 1.2 mm or less, preferably 1.1 mm or less, and particularly preferably 1.0 mm or less. When the maximum particle size is 1.2 mm or less, the strength (compressive strength and bending strength) and fracture resistance of the cementum hardened body are high.
The particle size distribution of the aggregate A is such that the particle size of the aggregate A is 0.6 mm or less from the viewpoint of improving the fluidity of the cement composition and increasing the strength (compressive strength and bending strength) and fracture resistance of the hardened cement material. The proportion of aggregate is 95% by mass or more, the proportion of aggregate having a particle size of 0.3 mm or less is 40 to 50% by mass, and the proportion of aggregate having a particle size of 0.15 mm or less is 6% by mass or less. Is preferable.
The proportion of aggregate A in the cement composition is preferably 20-40% by volume, more preferably 22-38% by volume, even more preferably 30-37% by volume, and particularly preferably 32-36% by volume. When the ratio is 20% by volume or more, the calorific value of the cement composition becomes small and the shrinkage amount of the cementum hardened body becomes small. When the ratio is 40% by volume or less, the strength (compressive strength and bending strength) and fracture resistance of the cementum hardened body become higher.

As the high-performance water reducing agent, a high-performance water reducing agent such as naphthalene sulfonic acid-based, melamine-based, or polycarboxylic acid-based can be used. Above all, a polycarboxylic acid-based high-performance water reducing agent is preferable from the viewpoint of improving the fluidity of the cement composition and increasing the strength (compressive strength and bending strength) and fracture resistance of the hardened cementum.
The blending amount of the high-performance water reducing agent is preferably 0.2 to 1.5 parts by mass, more preferably 0.4 in terms of solid content, with respect to 100 parts by mass of the total amount of cement, silica fume and the inorganic powder. ~ 1.3 parts by mass. When the amount is 0.2 parts by mass or more, the water reduction performance is improved and the fluidity of the cement composition is improved. When the amount is 1.5 parts by mass or less, the strength (compressive strength and bending strength) and fracture resistance of the cementum hardened body become higher.

As the defoaming agent, a commercially available product can be used.
The amount of the defoaming agent to be blended is preferably 0.001 to 0.1 parts by mass, more preferably 0.01 to 0.07 parts by mass, particularly, with respect to 100 parts by mass of the total amount of cement, silica fumes and inorganic powder. It is preferably 0.01 to 0.05 parts by mass. When the amount is 0.001 part by mass or more, the strength development of the cement composition is improved. When the amount exceeds 0.1 parts by mass, the effect of improving the strength development of the cement composition reaches a plateau.

Examples of the metal fiber include steel fiber, stainless steel fiber, amorphous fiber and the like. Among them, steel fiber is excellent in strength, and is suitable from the viewpoint of cost and availability.
The dimensions of the metal fibers are 0.01 to 1.0 mm in diameter and length from the viewpoint of preventing material separation of the metal fibers in the cement composition and increasing the bending strength and breakage resistance of the hardened cement material. Is preferably 2 to 30 mm, more preferably 0.05 to 0.5 mm in diameter and 5 to 25 mm in length. The aspect ratio (fiber length / fiber diameter) of the metal fiber is preferably 20 to 200, more preferably 40 to 150.
Further, the shape of the metal fiber is preferably a shape (for example, a spiral shape or a corrugated shape) that imparts some physical adhesive force rather than a linear shape. If the shape is spiral or the like, the metal fiber and the matrix secure the stress while being pulled out, so that the bending strength and fracture resistance of the cementum hardened body are increased.
The proportion of metal fibers in the cement composition is more than 3.0% by volume and 4.5% by volume or less, preferably 3.2 to 4.2% by volume, more preferably 3.3 to 3.7% by volume. Is. When the ratio is 3.0% by volume or less, the bending strength and fracture resistance of the hardened cementum are lowered. When the ratio exceeds 4.5% by volume, the fluidity and workability of the cement composition are greatly reduced.

Examples of the organic fiber include aramid fiber, polyparaphenylene benzobisoxazole fiber, polyethylene fiber, polyarite fiber, polypropylene fiber, polyvinyl alcohol fiber and the like. Of these, polypropylene fiber is preferable from the viewpoint of easy availability and improvement of fire resistance of the hardened cementum.
The dimensions of the organic fiber are 0.005 to 1.000 mm in diameter and 2 to 30 mm in length from the viewpoint of preventing the separation of the organic fiber material in the cement composition and improving the fire resistance of the hardened cement material. It is preferably 0.008 to 0.500 mm in diameter and 4 to 25 mm in length, and 0.010 to 0.030 mm in diameter and 4 to 10 mm in length. Is more preferable, and it is particularly preferable that the diameter is 0.012 to 0.020 mm and the length is 4 to 8 mm.

The aspect ratio (fiber length / fiber diameter) of the organic fiber is preferably 20 to 500, more preferably 30 to 490, still more preferably 200 to 480, still more preferably 230 to 470, and particularly preferably 300 to 450. be.
Above all, from the viewpoint of further improving the fire resistance of the hardened cement material, polypropylene fibers having a diameter of 0.010 to 0.030 mm, a length of 4 to 10 mm, and an aspect ratio (fiber length / fiber diameter) of 230 to 480. Is preferable, polypropylene fibers having a diameter of 0.010 to 0.020 mm, a length of 4 to 8 mm, and an aspect ratio (fiber length / fiber diameter) of 300 to 470 are more preferable, and a diameter of 0.012 to 0.020 mm is preferable. Polypropylene fibers having a length of 4 to 8 mm and an aspect ratio (fiber length / fiber diameter) of 300 to 450 are particularly preferable.
The proportion of organic fibers in the cement composition is preferably 0.01-0.5% by volume, more preferably 0.03 to 0.4% by volume, even more preferably 0.05 to 0.3% by volume, further. It is preferably 0.07 to 0.25% by volume, and particularly preferably 0.09 to 0.2% by volume. When the ratio is 0.01% by volume or more, the fire resistance of the hardened cementum is further improved. When the ratio is 0.5% by volume or less, the strength (compressive strength and bending strength) and fracture resistance of the cementum hardened body become higher.

As water, tap water or the like can be used.
The blending amount of water is preferably 10 to 20 parts by mass, more preferably 11 to 18 parts by mass, and particularly preferably 14 to 16 parts by mass with respect to 100 parts by mass of the total amount of cement, silica fume and inorganic powder. When the amount is 10 parts by mass or more, the fluidity of the cement composition is improved. When the amount is 20 parts by mass or less, the strength (compressive strength and bending strength) and fracture resistance of the cementum hardened body become higher.

The flow value of the mortar composed of the above cement composition (without the aggregate B described later) before curing is 15 times in the method described in "JIS R 5201 (Physical test method for cement) 11. Flow test". The value measured without the falling motion (hereinafter, also referred to as “0 stroke flow value”) is preferably 150 mm or more, more preferably 155 mm or more, and particularly preferably 160 mm or more.
When the flow value is 150 mm or more, workability when manufacturing a safe can be improved.
Further, the compressive strength of the hardened cement material obtained by hardening the mortar made of the above cement composition (which does not contain the aggregate B described later) is preferably 300 N / mm ² or more, more preferably 320 N / mm ² or more. , more preferably 330N / mm ² or more, more preferably 350 N / mm ² or more, more preferably 370N / mm ² or more, and particularly preferably 400 N / mm ² or more.

The aggregate A has a modified Mohs hardness of 9 or more (preferably 9 to 14, more preferably 10 to 13, particularly preferably 11 to 13) (for example, natural or artificial (artificial) emery sand. According to a mortar made of a cement composition using (alumina or a coarsely pulverized product of carbide, etc.) (which does not contain aggregate B described later), the compressive strength of the hardened cement material can be 400 N / mm ² or more. can. In particular, according to natural or artificial (artificial) emery sand, the compressive strength of the hardened cementum can be 430 N / mm ² or more.

The cement composition of the present invention can contain an aggregate B having a maximum particle size of more than 1.2 mm and 13 mm or less.
The aggregate B includes river sand, mountain sand, land sand, sea sand, crushed sand, silica sand, natural emery sand, artificial fine aggregate (for example, slag fine aggregate, fly ash, etc.). , Artificial (artificial) emery sand), recycled fine aggregate, river gravel, mountain gravel, land gravel, crushed stone, artificial coarse aggregate (for example, slag coarse aggregate, fly ash, etc. Materials), recycled coarse aggregates, coarsely pulverized alumina or carbides (eg, silicon carbide, boron carbide, etc.), or mixtures thereof.
The maximum particle size of the aggregate B is 13 mm or less, preferably 12 mm or less, more preferably 11 mm or less, and particularly preferably 10 mm or less. When the maximum particle size is 13 mm or less, the strength development of the cement composition is improved, and for example, ^{a compressive strength of 270 N / mm 2} or more can be developed.
The maximum particle size of the aggregate B is a value exceeding 1.2 mm from the viewpoint of cost reduction and the like, preferably 3 mm or more, more preferably 5 mm or more, and particularly preferably 7 mm or more.
In the present specification, the "maximum particle size" when the maximum particle size of the aggregate B is 5 mm or more is the nominal size of the sieve having the smallest size among the sieves through which 90% by mass or more of the entire aggregate B passes. Refers to the particle size of the aggregate B indicated by (generally known as the definition of the maximum particle size of the coarse aggregate).

The minimum particle size of the aggregate B is preferably a value exceeding the maximum particle size of the aggregate A, more preferably 2 mm or more, still more preferably 3 mm or more, still more preferably 4 mm or more, and particularly preferably 5 mm or more (in this case). , Corresponds to coarse aggregate.).
In the present specification, the minimum particle size of the aggregate B is the entire aggregate B when the particle size is accumulated from the smallest particle size to the larger particle size in the aggregate B. The particle size of the aggregate B when it reaches 15% by mass.

In the present invention, the ratio of the total amount of the aggregate A and the aggregate B in the cement composition is preferably 25 to 40% by volume, more preferably 28 to 38% by volume, and particularly preferably 30 to 36% by volume. .. When the ratio is 25% by volume or more, the calorific value of the cement composition becomes small and the shrinkage amount of the cementum hardened body becomes small. When the ratio is 40% by volume or less, the strength (compressive strength and bending strength) and fracture resistance of the hardened cementum can be further increased.
The ratio of the aggregate B to the total amount of the aggregate A and the aggregate B is preferably 40% by volume or less, more preferably 30% by volume or less, and particularly preferably 25% by volume or less. When the ratio is 40% by volume or less, the strength (compressive strength and bending strength) and fracture resistance of the hardened cementum can be further increased.
Compressive strength of the aggregate cement composition comprising a B (e.g., concrete) cementitious cured body obtained by curing is preferably 270N / mm ² or more, more preferably 280N / mm ² or more, more preferably 290 N / mm ² or more, more preferably 300N / mm ² or more, more preferably 310N / mm ² or more, and particularly preferably 315N / mm ² or more.

Hereinafter, the safe of the present invention will be described with reference to FIG.
The safe 1 includes a safe body 2 and a safe door 3. The shape of the safe 1 is not particularly limited, and may be any general shape of the safe.
One or both of the safe body 2 and the safe door 3 has outer surface plate portions 4a and 5a for forming the outer surface of the safe 1, inner surface plate portions 4b and 5b for forming the inner surface of the safe 1, and outer surfaces. Metal plate structures 4 and 5 having a storage space interposed between the face plate portions 4a and 5a and the inner surface plate portions 4b and 5b, and cementic hardening housed in a part of the storage space of the metal plate structures 4 and 5. The bodies 6 and 7 and the heat insulating materials 8 and 9 housed in the rest of the storage space of the metal plate structures 4 and 5 are included.
The cementum hardened bodies 6 and 7 and the heat insulating materials 8 and 9 are formed in the accommodation space of the metal plate structures 4 and 5 from the outside to the inside of the safe 1 with a layer composed of the cementum hardened bodies 6 and 7 and a heat insulating material. The layers composed of 8 and 9 are housed so as to be arranged in this order.
As shown in FIG. 1, the hardened cementum and the heat insulating material may contain the hardened cementum 6 and 7 on the outer surface side of the safe 1 and the heat insulating materials 8 and 9 on the inner surface side of the safe 1. Alternatively, the cementitious hardened material may be accommodated on the inner surface side of the safe, and the heat insulating material may be accommodated on the outer surface side of the safe. Further, the heat insulating material or the like may be accommodated so that the cementum cured material is arranged on both sides of the heat insulating material, and the layer made of the cementum hardened material may be laminated on both sides of the layer made of the heat insulating material.

The metal plate structures 4 and 5 may have partition wall portions 4c and 5c for separating the cementitious hardened bodies 6 and 7 and the heat insulating materials 8 and 9. By having the partition wall portions 4c and 5c, the crime prevention property of the safe 1 can be further improved.
The outer surface plate portions 4a and 5a, the inner surface plate portions 4b and 5b, and the partition wall portions 4c and 5c constituting the metal plate structures 4 and 5 are fixed to each other by welding or the like.
Examples of the material of the metal plate structures 4 and 5 include iron, aluminum, copper, stainless steel, titanium, and steel.
The outer surface plate portion refers to a surface portion of the metal plate structure that can be visually recognized when the safe door is closed. The inner surface plate portion refers to a visible surface portion of the inside of the safe (the surface portion of the safe excluding the outer surface plate portion of the safe) when the door of the safe is opened in the metal plate structure. The partition wall is an invisible part of the metal plate structure.

Examples of the materials of the heat insulating materials 8 and 9 include calcium silicate, rock wool, and synthetic resin foam. Since the safe 1 has the heat insulating materials 8 and 9, the fire resistance and the heat insulating property of the safe can be further improved.
Each member (cementum hardened body 6, 7, etc.) of the safe 1 is fixed by using an adhesive such as epoxy resin, a bolt, or the like.

Hereinafter, a method for manufacturing a safe using a hardened cementum obtained by hardening the above-mentioned cement composition will be described in detail.
An example of the method for manufacturing a safe of the present invention is a molding step of casting the above-mentioned cement composition into a mold to obtain an uncured molded body, and an uncured molded body at 10 to 40 ° C. 24. A normal temperature curing process for obtaining a cured molded body by sealing or aerial curing for an hour or longer, and steam curing or hot water curing for 6 hours or more at 70 ° C or higher and lower than 100 ° C for the cured molded body, 100 to 200. One or both of the autoclave curing at ° C for 1 hour or more is performed to obtain a cured product after heat curing, and the cured product after heat curing is heated at 150 to 200 ° C for 24 hours or more (however). (Excluding heating by autoclave curing), it includes a high-temperature heating step to obtain a cement hardened body and an assembly step to make a safe using the cemented hardened body, a metal plate structure and a heat insulating material.

[Molding process]
This step is a step of casting the cement composition into the mold to obtain an uncured molded product.
The method of kneading the cement composition before casting is not particularly limited. Further, the apparatus used for kneading is not particularly limited, and a conventional mixer such as an omni mixer, a pan-type mixer, a biaxial kneading mixer, and a tilting mixer can be used. Further, the casting (molding) method is not particularly limited.
The uncured molded product in this step may be made of a cement composition in which air bubbles in the cement composition are reduced or removed. By reducing or removing air bubbles in the cement composition, the strength (compressive strength and bending strength) and fracture resistance of the hardened cementum can be further increased.
As a method for reducing or removing air bubbles in the cement composition, (1) a method of kneading the cement composition under reduced pressure, and (2) before placing the kneaded cement composition in a mold. Examples thereof include a method of defoaming by reducing the pressure, and (3) a method of placing the cement composition in a mold and then defoaming by reducing the pressure.

In the molding step, the above-mentioned metal plate structure (at least a part of the metal plate structure) may be used as at least a part of the formwork. For example, in FIG. 1, a box-shaped structure formed by welding an outer surface plate portion 4a and a partition wall portion 4c may be used as a formwork, and the cement composition may be filled (cast) inside the formwork. ..

[Room temperature curing process]
In this step, the uncured molded product is sealed or cured in the air at 10 to 40 ° C. (preferably 15 to 30 ° C.) for 24 hours or more (preferably 24-72 hours, more preferably 24-48 hours). This is a step of obtaining a cured molded product.
When the curing temperature is 10 ° C. or higher, the curing time can be shortened. When the curing temperature is 40 ° C. or lower, the strength (compressive strength and bending strength) and fracture resistance of the hardened cementum can be further increased.
If the curing time is 24 hours or more, defects such as chips and cracks are less likely to occur in the cured molded product during demolding.
When a general formwork is used (when a metal plate structure is not used as at least a part of the formwork), the molded body cured in this step is removed from the formwork.
When at least a part of the metal plate structure is used as the formwork, since the formwork is used as a part of the safe, the metal plate structure part of the formwork is not removed from the mold.
Further, in this step, when the cured molded product ^{exhibits a compressive strength of preferably 20 to} 100 N / mm 2, more preferably 30 to 80 N / mm ² , the cured molded product is removed from the mold. Is preferable. When the compressive strength is 20 N / mm ² or more, defects such as chips and cracks are less likely to occur in the cured molded product during demolding. When the compressive strength is 100 N / mm ² or less, the cured molded product can be made to absorb water with less labor in the water absorption step described later.

[Water absorption process]
When a general formwork is used (when a metal plate structure is not used as at least a part of the formwork), the curing obtained in the normal temperature curing step between the normal temperature curing step and the heat curing step is performed. It may include a water absorption step of causing the molded body to absorb water.
Examples of the method of allowing the cured molded product to absorb water include a method of immersing the molded product in water. Further, in the method of immersing the molded body in water, from the viewpoint of increasing the amount of water absorption in a short time and further increasing the strength (compressive strength and bending strength) and fracture resistance of the cemented hardened body, (1) the molding. A method of immersing the body in water under reduced pressure, (2) After immersing the molded body in boiling water, the water temperature is lowered to 40 ° C. or lower while the molded body is immersed. A method for lowering the temperature, (3) a method of immersing the molded product in boiling water, then removing the molded product from the boiling water, and then immersing the molded product in water at 40 ° C. or lower. (4) Immersing the molded body in water under pressure, or (5) Immersing the molded body in an aqueous solution in which a chemical that improves the permeability of water into the molded body is dissolved. The method of making the water is preferable.

Examples of the method of immersing the molded body in water under reduced pressure include a method using equipment such as a vacuum pump and a large decompressing container.
Examples of the method of immersing the molded product in boiling water include a method of using equipment such as a high-temperature high-pressure container and a hot-heated water tank.
The time for immersing the cured molded product in water under reduced pressure or boiling water is preferably 3 minutes or longer, more preferably 8 minutes or longer, and particularly preferably 20 minutes, from the viewpoint of increasing the water absorption rate. That is all. The upper limit of the time is preferably 60 minutes, more preferably 45 minutes from the viewpoint of increasing the strength (compressive strength and bending strength) and fracture resistance of the hardened cementum.

The water absorption rate in the water absorption step is determined when the cement composition does not contain coarse aggregate (when the cement composition does not contain aggregate B or when aggregate B in the cement composition does not correspond to coarse aggregate). The ratio of water to 100% by volume of the cured compact of φ50 × 100 mm is preferably 0.20% by volume or more, more preferably 0.30 to 2.0% by volume, and further preferably 0.35 to 1.5% by volume. %, More preferably 0.36 to 1.0% by volume, particularly preferably 0.37 to 0.80% by volume, when the cement composition contains coarse aggregate (aggregate in cement composition). (When B corresponds to coarse aggregate), the ratio of water to 100% by volume of the cured compact of φ100 × 200 mm is preferably 0.20% by volume or more, more preferably 0.30 to 2.0% by volume. It is more preferably 0.35 to 1.5% by volume, still more preferably 0.36 to 1.0% by volume, and particularly preferably 0.37 to 0.80% by volume.
When these water absorption rates are 0.20% by volume or more, the strength (compressive strength and bending strength) and fracture resistance of the hardened cementum can be further increased.
When a metal plate structure is used as at least a part of the formwork, the cured molded body cannot be made to absorb water even if the water absorption step is performed.

[Heat curing process]
In this step, the cured molded product obtained in the previous step is subjected to steam curing or hot water curing at 70 ° C. or higher and lower than 100 ° C. (preferably 75 to 95 ° C., more preferably 80 to 92 ° C.) for 6 hours or longer. This is a step of performing one or both of autoclave curing at 100 to 200 ° C. (preferably 160 to 190 ° C.) for 1 hour or more to obtain a cured product after heat curing.
When only steam curing or hot water curing is performed in this step, the curing time is preferably 24 hours or more, more preferably 24-96 hours, and particularly preferably 36 to 72 hours. When only autoclave curing is performed, the curing time is preferably 8 to 60 hours, more preferably 12 to 48 hours. When performing both steam curing or hot water curing and autoclave curing (for example, when performing steam curing or hot water curing and then autoclave curing), the curing time in steam curing or hot water curing is preferably 6 to 72 hours. , More preferably 12 to 48 hours, and the curing time in autoclave curing is preferably 1 to 24 hours, more preferably 4 to 18 hours.
In this step, if the curing temperature is within the above range, the curing time can be shortened, and the strength (compressive strength and bending strength) and fracture resistance of the hardened cementum can be further increased.
Further, in this step, if the curing time is within the above range, the strength (compressive strength and bending strength) and fracture resistance of the cementitious cured product can be further increased.

[High temperature heating process]
In this step, the cured product after heat curing is heated at 150 to 200 ° C. (preferably 170 to 190 ° C.) for 24 hours or more (preferably 24-72 hours, more preferably 36 to 48 hours) and heated (however, autoclave). This is a step of obtaining a cementified hardened body obtained by hardening the cement composition by (excluding heating by curing).
The heating in this step is usually performed in a dry atmosphere (in other words, in a state where water or steam is not artificially supplied).
When the heating temperature is 150 ° C. or higher, the heating time can be further shortened. When the heating temperature is 200 ° C. or lower, the strength (compressive strength and bending strength) and fracture resistance of the hardened cementum can be further increased.
When the heating time is 24 hours or more, the strength (compressive strength and bending strength) and fracture resistance of the hardened cementum can be further increased.

Since the obtained hardened cementum has high compressive strength, it is less likely to crack and has excellent crime prevention properties.
It also has excellent fire resistance.
In addition, the obtained hardened cementum has excellent dimensional stability. When a 40 × 40 × 160 mm specimen measured in accordance with “JIS A 1129-2: 2010 (Mortar and concrete length change measurement method-Part 2: Contact gauge method)” is stored for 6 months. The shrinkage strain of the hardened cementum is preferably 10 × 10 ^-6 or less, more preferably 8 × 10 ^-6 or less, and particularly preferably 6 × 10 ^-6 or less.
Further, the obtained cementitious hardened body has a large bending strength. The bending strength of the hardened cement material measured in accordance with "JSCE-G 552-2010 (Bending strength and bending toughness test method of steel fiber reinforced concrete)" is preferably 45 N / mm ² or more. preferably 48N / mm ² or more, more preferably 50 N / mm ² or more, and particularly preferably 53N / mm ² or more.
Further, the obtained hardened cementum has excellent fracture resistance.

[Assembly process]
This step is a step of manufacturing the above-mentioned safe using the cementitious hardened body, the metal plate structure and the heat insulating material obtained in the high temperature heating step.
When a general formwork is used (when a metal plate structure is not used as at least a part of the formwork), a cementic hardened body and a metal plate structure (outer surface plate part, inner surface plate part, partition wall) Part) and a heat insulating material are prepared, and the above-mentioned safe can be manufactured by fixing each of them using an epoxy resin or the like. The order in which each member is fixed is not particularly limited, but for example, after fixing the cementum hardened body to the outer surface plate portion, the heat insulating material is fixed to the cementum hardened body, and then the inside of the heat insulating material. Examples thereof include a method of fixing the face plate portion.
When a metal plate structure is used as at least a part of the formwork (for example, when a formwork consisting of an outer surface plate portion and a partition wall portion is used), the safe of the metal plate structure containing the cementified hardened material is used. Examples thereof include a method of fixing the heat insulating material to the surface (partition wall portion) on the inner surface side and then fixing the inner surface plate portion to the heat insulating material.

The safe of the present invention is excellent in crime prevention and fire resistance because it has a high compressive strength and bending strength and contains a cementitious hardened body having excellent fracture resistance and fire resistance. Further, since the safe of the present invention contains a heat insulating material, it has excellent heat insulating properties.

Hereinafter, the present invention will be specifically described with reference to Examples, but the present invention is not limited to these Examples.
[Material used]
(1) Cement: Low heat Portland cement (manufactured by Taiheiyo Cement)
(2) Silica fume: BET specific surface area 20 m ² / g
(3) Inorganic powder: silica stone powder, 50% volume cumulative particle size 2 μm, maximum particle size 12 μm, 95% volume cumulative particle size 5.8 μm
(4) Aggregate A (fine aggregate): Silica sand (maximum particle size 1.0 mm, particle size of 0.6 mm or less: 98% by mass, particle size of 0.3 mm or less: 45% by mass, 0 .For particles with a particle size of 15 mm or less: 3% by mass)
(5) Polycarboxylic acid-based high-performance water reducing agent: solid content 27.4% by mass, manufactured by Floric, trade name "Floric SF500U"
(6) Defoamer: Made by BASF Japan, trade name "Master Air 404"
(7) Water: Tap water (8) Metallic fiber: Steel fiber (diameter: 0.2 mm, length: 15 mm)
(9) Organic fiber: Polypropylene fiber (diameter: 0.014 mm, length: 6 mm, aspect ratio: 429)
(10) Aggregate B (coarse aggregate): Hard sandstone crushed stone 1005 (grain size: 5 to 10 mm)

[Example 1]
Cement, silica fume and inorganic powder were mixed so that each ratio of cement and the like was shown in Table 1 in 100% by volume of the total amount of the powder raw materials (cement, silica fume and inorganic powder). The obtained mixture and the amount of the aggregate A in which the ratio of the aggregate A in the cement composition became the ratio shown in Table 1 were put into the omnimixer and kneaded for 15 seconds.
Then, water, a polycarboxylic acid-based high-performance water reducing agent, and an antifoaming agent were added to the omnimixer in the amounts shown in Table 1 and kneaded for 2 minutes.
After kneading, the kneaded material adhering to the side wall in the omnimixer was scraped off, and kneading was further performed for 4 minutes.
Then, the amount of the fiber whose ratio of the metal fiber and the organic fiber in the cement composition became the ratio shown in Table 1 was put into the omnimixer, and kneaded for another 2 minutes.
The flow value of the cement composition after kneading was measured in the method described in "JIS R 5201 (Physical test method for cement) 11. Flow test" without performing 15 drop motions. In the present specification, the flow value is referred to as "0 stroke flow value".

The obtained kneaded product was cast into a cylindrical mold having a diameter of 50 × 100 mm to obtain an uncured molded product. After casting, the uncured molded product was sealed and cured at 20 ° C. for 48 hours, and then demolded to obtain a cured molded product. The compressive strength at the time of demolding was 43 N / mm ² .
This molded product was immersed in water for 30 minutes in a depressurized desiccator (indicated as "under reduced pressure" in Table 2). The depressurization was performed using an "Aspirator (AS-01)" manufactured by AS ONE Corporation. The mass of the molded product before and after immersion was measured, and the water absorption rate was calculated from the obtained measured values.
After the immersion, the molded product was steam-cured at 90 ° C. for 48 hours, then lowered to 20 ° C., and then heated at 180 ° C. for 48 hours.
The compressive strength of the molded body (hardened cementum) after heating was measured according to "JIS A 1108 (compressive strength test method for concrete)".
In addition, the bending strength of the molded body (hardened cement material) after heating was measured according to "JSCE Standard JSCE-G 552-2010 (Bending strength and bending toughness test method of steel fiber reinforced concrete)".

Further, the heated molded body (cementum hardened body) was heated using a refractory furnace, and the fire resistance when heated for 60 minutes and the fire resistance when heated for 180 minutes were evaluated. The heating was performed for a predetermined time (60 minutes or 180 minutes) according to the heating curve defined in "ISO834", and after heating, it was naturally cooled. The maximum temperature in the above heating was 900 ° C. when heated for 60 minutes and 1,100 ° C. when heated for 180 minutes.

Further, a flat plate specimen having a length of 550 mm, a width of 100 mm, and a thickness of 25 mm was produced in the same manner as the molded product (cementum cured product) after heating.
As shown in FIG. 2, a steel weight 12 (mass 20 kg, tip diameter 200 mm) is placed in the center of the flat plate specimen 11, the first time is 10 cm, the second time is 20 cm, and the third time is 30 cm. By increasing the drop height by 10 cm each time the number increases and letting it fall freely (for example, the fifth free fall is performed from a height of 50 cm), repeated loading is applied, and the flat plate specimen is dropped at any number of times. The number of times that 11 broke was measured.
The impact resistance of the cementum hardened body was evaluated using the obtained number of times. The larger the number of times, the better the impact resistance.
Table 2 shows the evaluation (number of times) of 0-strike flow value, water absorption rate, compressive strength, bending strength, fire resistance and impact resistance. In Table 2, "◎" indicates that the fire resistance is extremely excellent (the crack width of the molded product after cooling is less than 1 mm), and "○" is excellent in fire resistance (after cooling). The crack width of the molded product is 1 mm or more and less than 10 mm), and "x" indicates that the fire resistance is inferior (the crack width of the molded product after cooling is 10 mm or more and there is peeling). ..
Table 2 also shows the 0-stroke flow values and the like in the examples and comparative examples described later.

[Example 2]
The cement composition and cementum hardening were carried out in the same manner as in Example 1 except that the blending amount of the polycarboxylic acid-based high-performance water reducing agent was changed to 0.95 parts by mass and the blending ratio of the metal fiber was changed to 3.5% by volume. I got a body. The compressive strength at the time of demolding was 43 N / mm ² .
Further, in the same manner as the molded body (hardened cement material) after heating, a test piece having a size of 40 × 40 × 160 mm was produced, and “JIS A 1129-2: 2010 Method for Measuring Length Change of Mortar and Concrete-No. When the shrinkage strain was measured after storage for 6 months in accordance with "Part 2: Contact Gauge Method", the shrinkage strain was 3 × ^10-6 .
Furthermore, the durability of "ASTM C666 75" is used for the molded body (cementum hardened body) after heating, using the values measured in accordance with "JIS A 1148 (concrete freeze-thaw test method)". When the index (300 cycles) was calculated, the durability index was 100.
The durability index has a maximum value of 100, and the closer to the maximum value, the better the freeze-thaw resistance.

[Example 3]
The cement composition and cementum hardening were carried out in the same manner as in Example 1 except that the blending amount of the polycarboxylic acid-based high-performance water reducing agent was changed to 0.98 parts by mass and the blending ratio of the metal fiber was changed to 4.0% by volume. I got a body. The compressive strength at the time of demolding was 44 N / mm ² .
[Example 4]
A cement composition and a hardened cementum were obtained in the same manner as in Example 2 except that the molded product after demolding was immersed in boiling water instead of being immersed in water in a depressurized desiccator. The compressive strength at the time of demolding was 43 N / mm ² .

[Example 5]
20% by volume of silica fume and inorganic powder, 0.94 parts by volume of polycarboxylic acid-based high-performance water reducing agent, and 3.5% by volume of metal fiber in 100% by volume of powder raw material. A cement composition and a cemented hardened body were obtained in the same manner as in Example 4 except for the modification. The compressive strength at the time of demolding was 47 N / mm ² .
Further, in the same manner as in Example 2, the shrinkage strain was measured and the durability index was calculated. As a result, the shrinkage strain was 4 × ^10-6 , and the durability index was 100.
[Example 6]
In 100% by volume of powder raw material, 20% by volume of silica fume and inorganic powder, 0.86 parts by mass of polycarboxylic acid-based high-performance water reducing agent, and 3.5% by volume of metal fiber. Using aggregate B in an amount such that the proportion of aggregate B in the cement composition is 7.0% by volume, each material (powder raw material, aggregate A, water, polycarboxylic acid-based high performance) is used. After kneading the water reducing agent, metal fiber, organic fiber and defoaming agent), the aggregate B was further added to the omnimixer and kneaded for 1 minute to obtain a cement composition in the same manner as in Example 4. .. Next, a hardened cementum was obtained in the same manner as in Example 4 except that the obtained cement composition (kneaded product) was cast into a cylindrical mold having a diameter of 100 × 200 mm. The compressive strength at the time of demolding was 35 N / mm ² .

[Comparative Example 1]
Example 1 except that the blending amount of the polycarboxylic acid-based high-performance water reducing agent was changed to 0.83 parts by volume, the blending ratio of the metal fiber was changed to 2.0% by volume, and the blending ratio of the organic fiber was changed to 0.2% by volume. In the same manner as above, a cement composition and a hardened cement material were obtained. The compressive strength at the time of demolding was 44 N / mm ² .
For the cement compositions obtained in Examples 2 to 5 and Comparative Example 1, the zero-strike flow value of the cement composition was measured in the same manner as in Example 1.
[Comparative Example 2]
The cement composition and cementum hardening were carried out in the same manner as in Example 1 except that the blending amount of the polycarboxylic acid-based high-performance water reducing agent was changed to 1.20 parts by mass and the blending ratio of the metal fiber was changed to 5.0% by volume. I got a body.
In the same manner as in Example 1, the zero-strike flow value of the cement composition was measured.
Moreover, since the obtained cement composition had poor fluidity and workability, it could not be molded.

From Table 2, it can be seen that the compressive strength of the cementum hardened body (those not containing the aggregate B) in Examples 1 to 5 is 403 N / mm ² or more, which is very large.
Further, it can be seen that the compressive strength of the cementum hardened body (including the aggregate B (coarse aggregate)) in Example 6 is 315 N / mm ^{2, which is large.}
Further, the bending strength of the hardened cement material (blending ratio of metal fibers: 3.1 to 4.0% by volume) in Examples 1 to 5 was 60 N / mm ² or more, and the hardened cement material (hardened metal fiber) in Comparative Example 1 ( ^{It can be seen that the bending strength (41 N / mm 2} ) of the metal fiber compounding ratio (2.0% by volume) is very large.
Further, it can be seen that the impact resistance (8 to 9 times) of the cementum hardened body in Examples 1 to 6 is superior to the impact resistance (6 times) of the cementum hardened body in Comparative Example 1.
Further, it can be seen that the cementum hardened bodies in Examples 1 to 6 are excellent in fire resistance.
From these results, it can be seen that the safe of the present invention using the hardened cementum is excellent in crime prevention and fire resistance.
Further, it can be seen that the shrinkage strain of the cementum hardened body in Examples 2 and 5 ^{is as small as 3 × 10 -6} to 4 × 10 ^-6 , and the durability index is 100.
From these results, it can be seen that the safe of the present invention using the hardened cementum is excellent in dimensional stability and freeze-thaw resistance.

1 Safe 2 Safe body 3 Safe door 4, 5 Metal plate structure 4a, 5a Outer plate part 4b, 5b Inner surface plate part 4c, 5c Partition part 6, 7 Cementum hardened body 8, 9 Insulation material 11 Flat plate specimen 12 Steel Weight made

Claims (6)

A safe with a safe body and a safe door,
One or both of the safe body and the safe door has an outer surface plate portion for forming the outer surface of the safe, an inner surface plate portion for forming the inner surface of the safe, and the outer surface plate portion and the inner surface. A metal plate structure having a storage space interposed between the face plates, a cemented hardened body housed in a part of the storage space of the metal plate structure, and the rest of the storage space of the metal plate structure. Includes insulation housed in
The hardened cement material is cement, silica fume with a BET specific surface area of 15 to 25 m ² / g, inorganic powder with a 50% volume cumulative particle size of 0.8 to 5 μm, and aggregate A with a maximum particle size of 1.2 mm or less. , High performance water reducing agent, defoaming agent, metal fiber , organic fiber and hardened cement composition containing water.
The metal fiber is a metal fiber having a diameter of 0.01 to 1.0 mm, a length of 2 to 30 mm, and an aspect ratio (fiber length / fiber diameter) of 20 to 200.
The organic fiber is a polypropylene fiber having a diameter of 0.010 to 0.020 mm, a length of 4 to 8 mm, and an aspect ratio (fiber length / fiber diameter) of 300 to 470.
In the total amount of 100% by volume of the cement, the silica fume and the inorganic powder, the ratio of the cement is 55 to 65% by volume, the ratio of the silica fume is 5 to 25% by volume, and the ratio of the inorganic powder is 15 to 35% by volume. And
The cement composition, the proportion of the metal fibers, safe to 3.3 to 3.7 vol%, the ratio of the organic fibers, characterized in that 0.01 to 0.3% by volume. The safe according to claim 1 , wherein the cement composition does not contain an aggregate having a maximum particle size of more than 1.2 mm, and the compressive strength of the cementum hardened body is 300 N / mm ² or more. The cement composition is greater than 1.2mm maximum particle size observed including the following aggregate B 13 mm, and the compressive strength of the cementitious cured product according to claim 1 is 270N / mm ² or more safe. The method for manufacturing the safe according to any one of claims 1 to 3.
The molding process of casting the above cement composition into a mold to obtain an uncured molded product, and
A normal temperature curing step of obtaining a cured molded product by sealing or aerial curing the uncured molded product at 10 to 40 ° C. for 24 hours or more.
The cured molded product is cured after heating by performing steam curing or hot water curing at 70 ° C. or higher and lower than 100 ° C. for 6 hours or longer, or autoclave curing at 100 to 200 ° C. for 1 hour or longer, or both. The heating process to get the body and
A high-temperature heating step of heating the cured product after heat curing at 150 to 200 ° C. for 24 hours or more (excluding heating by autoclave curing) to obtain a cementitious cured product, and
An assembly process for producing the safe using the cementitious hardened body, the metal plate structure, and the heat insulating material.
A method of manufacturing a safe, characterized by including. The method for manufacturing a safe according to claim 4 , further comprising a water absorption step of causing the cured molded product to absorb water between the normal temperature curing step and the heat curing step. The method for manufacturing a safe according to claim 4 , wherein the metal plate structure is used as at least a part of the formwork.

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