Method for making recycled fiber boards fireproof, and recycled fiber boards

Abstract

An object of the present invention is to provide a method for making a recycled fiberboard fireproof, which is compatible with the evaluation of fireproof materials as defined in the Building Standards Act. [Solution] The method for making a recycled fiber board-like body fire-retardant according to the present disclosure comprises the steps of: immersing a recycled fiber board-like body produced by compression molding waste fiber material in a fire-retardant liquid; reducing the pressure of the recycled fiber board-like body immersed in the fire-retardant liquid in an airtight container and maintaining it at a first pressure lower than atmospheric pressure for a first hour, and then pressurizing and maintaining it at a second pressure higher than atmospheric pressure for a second hour, thereby performing pressurized injection; and coating with a finishing material made of a fire-retardant material.

Description

[Technical Field]

[0001] The present invention relates to a method for rendering fire-retardant a recycled fiber board obtained by collecting and recycling discarded clothing, and to a recycled fiber board obtained by the fire-retardant treatment. [Background technology]

[0002] In recent years, approximately one million tons of clothing are discarded annually in Japan, most of which is disposed of as waste by incineration or landfill. Disposal of clothing as waste is undesirable due to the costs and energy required. Incineration recovers thermal energy in the form of steam and hot water, but the resulting carbon dioxide emissions contribute to global warming. Furthermore, textile materials, including clothing, have a high porosity and extremely low density, making them unsuitable for landfilling.

[0003] In this way, many efforts have been proposed to recycle clothing that would otherwise have been thrown away, but textile products such as clothing are manufactured from a mixture of various raw materials, such as natural cotton and synthetic chemical fibers, and the lengths of the fibers vary, making it extremely difficult to extract and recycle only specific components from textile products, which has been an obstacle to the recycling of textile products.In this situation, a technology has been proposed in which waste textile materials are compressed and molded into plate-shaped materials (Patent Document 1).

[0004] According to Patent Document 1, discarded textile materials such as clothing are crushed, then a thermosetting adhesive is added, and the materials are heated and compressed to form plates. The resulting plates are lightweight and retain the original colors and patterns of the original materials, such as clothing, making them unique and recyclable. These plates are then processed and used, for example, as materials for interior design, furniture, and fixtures, and are attracting attention as a material that can realize a circular production model.

[0005] However, the plates recycled by the technology described in Patent Document 1 are made from cotton or chemical fibers, which makes them highly flammable and limits their applications. For example, if one considers using them as building materials such as flooring or wall materials, it is difficult to use them as they are. If such waste fiber materials are to be used as building materials, it is preferable that they comply with the evaluation criteria for non-combustible materials set forth in the Building Standards Act. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Patent No. 7254401 Summary of the Invention [Problem to be solved by the invention]

[0007] The present invention has been made in view of the above-mentioned problems, and aims to provide a method for making recycled fiberboards fireproof that is compatible with the evaluation of fireproof materials stipulated in the Building Standards Act. [Means for solving the problem]

[0008] The present invention provides the following solutions.

[0009] The first feature of the method for making a recycled fiber board fireproof includes the steps of: immersing a recycled fiber board produced by compression molding waste fiber material in a fireproofing liquid; reducing the pressure of the recycled fiber board immersed in the fireproofing liquid in a sealed container and maintaining it at a first pressure lower than atmospheric pressure for a first hour; and then pressurizing the recycled fiber board and maintaining it at a second pressure higher than atmospheric pressure for a second hour, thereby performing pressure injection; Non-flammable materials and applying a finish comprising:

[0010] According to the first aspect of the invention, the fire retardant liquid can be reliably penetrated by the step of pressurizing the recycled fiber board immersed in the fire retardant liquid by depressurizing the recycled fiber board in a sealed container and holding it at a first pressure lower than atmospheric pressure for a first hour, and then pressurizing the recycled fiber board and holding it at a second pressure higher than atmospheric pressure for a second hour. In addition, since the recycled fiber board has a higher absorption rate than the wood board, the fire retardant liquid can be reliably penetrated by depressurizing and pressurizing the recycled fiber board for a shorter period of time. Non-flammable materials By including a step of covering the finishing material consisting of the above, it is possible to delay the ignition of the fiber material present inside the covering, and as a result, it is possible to obtain a recycled fiber board-like body that is suitable as a non-combustible material.

[0011] The method for making a recycled fiberboard material fireproof according to a second feature is the invention according to the first feature, and further includes a step of performing a drying process after the step of performing pressure injection.

[0012] According to the second feature of the invention, after the step of pressurized injection of the fire retardant liquid, a step of drying treatment is further included, which makes it possible to evaporate the water contained in the fire retardant liquid and leave only the solid content contained in the fire retardant liquid in the recycled fiberboard.

[0013] The third feature of the method for making a recycled fiberboard-like product fireproof is the invention of the first feature, in which the first pressure is set so as not to be lowered to 90% or less of atmospheric pressure.

[0014] According to the invention relating to the third feature, the first pressure, which is the holding pressure during decompression, is set so as not to be lowered below 90% of atmospheric pressure, so that the air in the fibers can be removed without volatilizing the fire retardant liquid agent, making the injection of the fire retardant liquid agent by subsequent pressurization more reliable. [Effects of the Invention]

[0015] According to the present invention, it is possible to provide a method for making a recycled fiberboard fireproof, which is compatible with the evaluation of fireproof materials as defined in the Building Standards Act. [Brief explanation of the drawings]

[0016] [Figure 1] FIG. 1 is a flowchart showing the fireproofing treatment method according to this embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0017] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The following describes embodiments of the present invention with reference to the accompanying drawings. However, these are merely examples, and the technical scope of the present invention is not limited to these examples.

[0018] [Fireproofing treatment method according to this embodiment] The fireproofing treatment method according to this embodiment will be described with reference to the flowchart shown in Fig. 1. Fig. 1 is a flowchart of the fireproofing treatment method according to this embodiment.

[0019] [Step S100: Preparation of Recycled Fiber Board] First, prior to the fireproofing treatment in the fireproofing treatment device, a recycled fiber board 10 to be treated is prepared (step S100). The recycled fiber board 10 is produced by ripping collected waste fiber material, mixing it with a thermoplastic resin, and then compression molding it. The recycled fiber board 10 may be produced on the site where the fireproofing treatment device is installed, or it may be prepared at a different site. The waste fiber material from which the recycled fiber board 10 is formed includes not only clothing but also products such as towels, sheets, and curtains, as well as the fabric and yarn used to make these products and clothing. The type of fiber is not particularly limited, and various types can be used. Examples include natural fibers and chemical fibers. Natural fibers include plant fibers such as cotton and hemp, and animal fibers such as silk, wool, and cashmere. Chemical fibers include synthetic fibers such as nylon, polyester, acrylic, and polyurethane, regenerated fibers such as rayon, and semi-synthetic fibers such as acetate.

[0020] [Step S110: Inserting the Recycled Fiber Board into the Container] Next, the recycled fiber boards 10 are placed in a tray-shaped container 20. At this time, by stacking the recycled fiber boards 10 in a frame (not shown) that leaves a predetermined gap between them, it is possible to simultaneously treat multiple recycled fiber boards 10 with fire retardancy using a single tray-shaped container 20. In this embodiment, a tray-shaped container 20 capable of containing recycled fiber boards 10 from above is used, but this is not limited to this type. Any shape may be used as long as the container has an opening in part, can contain recycled fiber boards 10, and can be charged with fire retardant liquid 30.

[0021] [Step S120: Immersion in fire retardant liquid] A fire-retardant liquid 30 is poured into the tray-shaped container 20 on which the recycled fiberboard 10 is placed, and the recycled fiberboard 10 is soaked in the fire-retardant liquid 30. The fire-retardant liquid 30 contains the fire retardants diammonium phosphate and guanylurea phosphate, and is produced by mixing the fire retardants with water as a solvent to produce a fire-retardant liquid 30 with a concentration of approximately 50%. By allowing these fire retardants to penetrate the recycled fiberboard 10, even if it ignites, instead of burning with a flame, a char layer is formed on the surface, and the char layer acts as an insulating layer to prevent the spread of fire. The recycled fiberboard 10 soaked in the fire-retardant liquid 30 is then inserted into the pressure vessel 40 along with the tray-shaped container 20.

[0022] [Step S130: Depressurizing the Pressure Vessel] After the tray-shaped container 20 containing the recycled fiber plate 10 and the fire-retardant solution 30 is inserted into the pressure vessel 40, the pressure vessel 40 is sealed and the pressure is reduced and maintained at a predetermined first pressure lower than atmospheric pressure for a predetermined first period of time. By reducing the pressure inside the pressure vessel 40, air trapped between the fibers in the recycled fiber plate 10 can be removed, facilitating penetration of the fire-retardant solution 30 into the material. In step S130, the pressure inside the pressure vessel 40 is maintained at approximately 0.095 to 0.098 MPa for at least two hours. The pressure inside the pressure vessel 40 is reduced, for example, using a vacuum pump (not shown). By setting the first pressure to 0.095 to 0.098 MPa, so as not to drop below 90% of atmospheric pressure, the air trapped between the fibers in the recycled fiber plate 10 can be removed while suppressing volatilization of the fire-retardant solution. In particular, the recycled fiber plate-like product 10 according to this embodiment has high flexibility and porosity, so that air can be reliably removed from between the fibers even at relatively high pressures below atmospheric pressure. The pressure vessel 40 functions as the airtight vessel in the present invention.

[0023] [Step S140: Pressurizing in a pressure vessel] In step S130, the pressure inside the pressure vessel 40 is reduced to remove the air contained in the fibers of the recycled fiber plate-like product 10, and then the pressure inside the pressure vessel 40 is pressurized and maintained at a predetermined second pressure higher than atmospheric pressure for a predetermined second time period. By pressurizing the pressure vessel 40, the fire retardant liquid agent 30 is forced into the recycled fiber plate-like product 10. In step S140, the pressure inside the pressure vessel 40 is maintained at approximately 1.0 MPa for six hours or more. The pressure inside the pressure vessel 40 is pressurized, for example, by a compressor (not shown).

[0024] [Step S150: Drying the Recycled Fiber Board] After the pressurized injection of the fire-retardant liquid agent 30 in step S140 is completed, the recycled fiber plate 10 impregnated with the fire-retardant liquid agent 30 is then dried. Drying the recycled fiber plate 10 impregnated with the fire-retardant liquid agent 30 raises the temperature of the recycled fiber plate 10, vaporizing the water from the fire-retardant liquid agent 30 within the recycled fiber plate 10 and leaving the solid portion of the fire-retardant liquid agent 30. The drying process in step S150 may be performed in a dedicated drying chamber after removing the recycled fiber plate 10 from the pressure vessel 40, or it may be performed inside the pressure vessel 40. The drying process in step S150 may include pre-drying in which the recycled fiber plate 10 is placed in the atmosphere for curing, and main drying in which the recycled fiber plate 10 is dried in a drying chamber maintained at a predetermined high temperature, e.g., 70°C. The high temperature in the drying chamber may be generated by indirect heating using steam or by supplying hot air. When step S150 is completed, the solid content of the fire retardant liquid agent 30 has permeated the recycled fiber board 10 and the recycled fiber board 10 has been dried, and the specific gravity of the recycled fiber board 10 increases by 0.3 compared to the initial state.

[0025] Step S160: Non-flammable materials Covering the finishing material with After the drying process in step S150, the recycled fiberboard 10 permeated with the fire-retardant liquid agent 30 is coated with a finishing material 50 (step S160). The finishing material 50 is selected from mortar, glass fiber, and a coating of Miracle Urea AP211 (room-temperature curing aliphatic polyurea). By coating with the finishing material 50, fire retardancy is ensured. In other words, even if the fire-retardant liquid agent 30 is permeated into the recycled fiberboard 10 in steps S120 to S150, the recycled fiberboard 10 is still made of fiber materials such as cotton and chemical fiber, and if the material itself catches fire, the fire may spread to adjacent fibers and eventually to surrounding fibers. In step S160, Non-flammable materials By covering the surface of the recycled fiber board 10 permeated with the fire retardant liquid agent 30 with the finishing material 50, it is possible to delay the ignition of the fiber material present inside the covering.

[0026] By carrying out the above steps, the recycled fiber plate 10 is made fireproof.

[0027] [Evaluation of the fireproofing treatment method according to this embodiment] Next, the evaluation of the fireproofing method according to this embodiment will be described. The evaluation was based on whether the material met the criteria for "noncombustible materials" as defined in Article 2, Paragraph 9 and Article 108-2 of the Building Standards Act. Specifically, the evaluation was based on whether the material "does not burn," "does not develop deformation, melting, cracking, or other damage that would be detrimental to fire safety," and "does not emit smoke or gases that would be detrimental to evacuation" for 20 minutes after heating commenced. Specifically, the following evaluation tests were conducted to determine whether the material met the following criteria: (1) total heat release of 8 MJ / m² or less, (2) maximum heat release rate of 200 kW / m² for more than 10 consecutive seconds, and (3) there were no cracks or holes penetrating to the back surface that would be detrimental to fire safety, even after 20 minutes of heating. The test method used was a cone calorimeter test in accordance with ISO 5660-1.

[0028] Example 1 The material according to Example 1 is a recycled fiberboard that has been subjected to the fireproofing method according to this embodiment, and mortar is used as the finishing material in step S160.

[0029] <Example 2> The material according to Example 2 is a recycled fiber board that has been subjected to the fire retardant treatment method according to this embodiment, and uses glass fiber as the finishing material in step S160.

[0030] <Comparative Example 1> The material of Comparative Example 1 is a recycled fiber board that has undergone a partial fire retardant treatment of the present embodiment. That is, the recycled fiber board has been subjected to the fire retardant treatment method of the present embodiment up to step S150, but has not been coated with a finishing material in step S160. That is, although the coating with a finishing material in step S160 has not been performed, the other steps up to step S150 have been performed under the same conditions as in Examples 1 and 2.

[0031] <Comparative Example 2> The material in Comparative Example 2 is a wooden board that has undergone a partial fire retardant treatment of the present embodiment. Specifically, the wooden board was immersed in a fire retardant, depressurized, and pressurized to allow the fire retardant to penetrate, and then dried. Specifically, a wooden board was used instead of a recycled fiber board, and the treatment up to step S150 was carried out under the same conditions as in Comparative Example 1. However, because the wooden board has a higher initial moisture content than the recycled fiber board 10, it was dried until the moisture content reached 14% or less as a pretreatment for impregnating the fire retardant liquid. Furthermore, because the wooden board has poorer absorbency than the recycled fiber board 10, the depressurization and pressurization times in steps S130 to S140 were longer than those for the recycled fiber board 10.

[0032] The test results are shown in Table 1. As shown in Table 1, it was revealed that the recycled clothing materials of Examples 1 and 2 obtained by carrying out the fire-retardant treatment according to this embodiment are suitable as fire-retardant materials, while the materials of Comparative Examples 1 and 2 are not suitable as fire-retardant materials. [Table 1]

[0033] The recycled fiber plate-like products of Examples 1 and 2 exhibited total heat release values ​​of 0.72 MJ / m and 0.22 MJ / m after 20 minutes of heating, respectively, which were 10 times or more the required performance. Furthermore, the maximum heat release rates were 2.92 kW / m and 1.98 kW / m, respectively, which significantly exceeded the required performance.

[0034] On the other hand, the recycled fiber board of Comparative Example 1 generated a total heat value of 101.46 MJ / m2 after 20 minutes of heating, which was more than 100 times the heat generated in Examples 1 and 2, which were subjected to the fire-retardant treatment according to this embodiment. The only difference between Examples 1 and 2 and Comparative Example 1 was the covering with the finishing material in step S160, and this result suggests that the covering with the finishing material was very effective.

[0035] On the other hand, the difference between Comparative Example 1 and Comparative Example 2 is whether the starting material is a recycled fiberboard or a wood board. It has become clear that, among the fire retardant treatment methods according to this embodiment, the fire retardant liquid agent penetration treatment in steps S110 to S150 can reliably penetrate the fire retardant liquid agent into the recycled fiberboard, thereby achieving high effectiveness.

[0036] That is, the fire retardant treatment method according to this embodiment includes a step of pressurized injection in which a recycled fiber board immersed in a fire retardant liquid agent is depressurized in a sealed container and held at a first pressure lower than atmospheric pressure for a first hour, and then pressurized and held at a second pressure higher than atmospheric pressure for a second hour, thereby ensuring the fire retardant liquid agent to penetrate the material. Moreover, because recycled fiber boards have a higher absorption rate than wood boards, the fire retardant liquid agent can be reliably penetrated by depressurizing and pressurizing for a shorter period of time without pre-treatment such as drying. Non-flammable materials By including a step of covering the finishing material consisting of the above, it is possible to delay the ignition of the fiber material present inside the covering, and as a result, it is possible to obtain a recycled fiber board-like body that is suitable as a non-combustible material.

[0037] In addition, after the step of pressurizing and injecting the fire-retardant liquid agent, a drying step is further included, which makes it possible to evaporate the moisture contained in the fire-retardant liquid agent and leave only the solid content contained in the fire-retardant liquid agent in the recycled fiberboard.

[0038] In addition, the first pressure, which is the holding pressure during decompression, is set so as not to drop below 90% of atmospheric pressure, so that the air in the fibers can be removed without volatilizing the fire-retardant liquid, making the injection of the fire-retardant liquid by subsequent pressurization more reliable.

[0039] Although the embodiments of the present invention have been described above, the present invention is not limited to these embodiments. Furthermore, the effects described in the embodiments of the present invention are merely a list of the most preferable effects resulting from the present invention, and the effects of the present invention are not limited to those described in the embodiments of the present invention.

[0040] Furthermore, the above-described embodiment has been described in detail to clearly explain the present invention, and is not necessarily limited to an embodiment having all of the configurations described. [Industrial Applicability]

[0041] The method for making a recycled fiberboard-like product fireproof according to the present invention can be applied as a method for making a waste fiber material made of various materials such as cotton and chemical fiber fireproof. [Explanation of symbols]

[0042] 10 Recycled fiber board 20 Tray-shaped container 30 Fire retardant liquid agent 40 Pressure vessel (sealed vessel) 50 Finishing Materials

Claims

1. a step of immersing a recycled fiber board produced by compression molding the waste fiber material in a fire retardant liquid agent; a step of performing pressure injection by reducing the pressure of the recycled fiber board immersed in the fire retardant liquid in a sealed container and maintaining it at a first pressure lower than atmospheric pressure for a first hour, and then pressurizing it and maintaining it at a second pressure higher than atmospheric pressure for a second hour; and applying a finish made of a non-combustible material; A method for making a recycled fiberboard-like body fireproof, comprising:

2. After the step of performing the pressure injection, a step of performing a drying process is further provided. The fireproofing treatment method according to claim 1.

3. The first pressure is set so as not to be lowered to 90% or less of atmospheric pressure. The fireproofing treatment method according to claim 1.

4. A recycled fiber board that has been subjected to the fire retardant treatment method according to any one of claims 1 to 3.

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