Method for manufacturing fiberboard, fiberboard, and fiberboard manufacturing system

Abstract

Provided are a method for manufacturing a fiberboard, the fiberboard, and a fiberboard manufacturing system capable of suppressing an increase in cost related to the manufacturing of the fiberboard. 【Solution means】A series of steps including a step (S1) of charging wood chips, a cooking step (S2), a defibrating step (S3), a first adhesive application step (S4), a first drying step (S5), a second adhesive application step (S6), a second drying step (S7), a mat forming step (S8), a hot pressing step (S9), and a grinding / cutting step (S10) are executed, and a fiber charging step (S11a, S11b) is executed between the first adhesive application step (S4) and the second adhesive application step (S6).

Description

Technical Field

[0001] The present invention relates to a method for manufacturing a fiberboard, a fiberboard, and a fiberboard manufacturing system.

Background Art

[0002] FIG. 3 is a process diagram showing a conventional method for manufacturing a fiberboard. Conventionally, as a method for manufacturing a fiberboard including a medium density fiberboard (MDF), the manufacturing process shown in FIG. 3 has been known. In the process line shown in FIG. 3, first, a wood chip feeding step of feeding wood chips into the line is carried out (So1), followed by a cooking step (So2), a defibering step (So3), an adhesive application step (So4), a drying step (So5), a mat forming step (So6), a hot pressing step (So7), and a grinding / cutting step (So8), and the manufacturing of a fiberboard of a desired size is completed. As such a method for manufacturing a fiberboard, for example, the applicant of the present application has proposed a method for manufacturing a fiberboard described in Patent Document 1.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] By the way, in recent years, as raw materials for manufacturing fiberboards, not only wood chips that have been conventionally used, but also waste materials containing fibers such as clothes and cardboard have been attracting attention as a method for performing meaningful recycling. When using waste materials containing fibers such as clothes and cardboard, separately from the cooking process and defibering process of wood chips, due to the mixing of waste materials, extra and large amounts of energy may be required in processes such as cooking and defibering, resulting in problems of poor efficiency and increased manufacturing costs.

[0005] The present invention has been made in view of such circumstances, and even when using waste materials, an object thereof is to provide a method for manufacturing a fiberboard capable of suppressing an increase in manufacturing cost, a fiberboard, and a fiberboard manufacturing system.

Means for Solving the Problems

[0006] In the method for manufacturing a fiberboard according to the present invention, in order to achieve the above object, the method for manufacturing a fiberboard according to the present invention includes a series of steps including a step of charging wood chips, a cooking step, a defibrating step, an adhesive application step, a drying step, a mat forming step, a hot pressing step, and a grinding / cutting step, and is characterized in that a fiber charging step is performed between the defibrating step and the adhesive application step.

[0007] Furthermore, the method for manufacturing a fiberboard according to the present invention includes a series of steps including a step of charging wood chips, a cooking step, a defibrating step, a first adhesive application step, a first drying step, a second adhesive application step, a second drying step, a mat forming step, a hot pressing step, and a grinding / cutting step, and is characterized in that a fiber charging step is performed between the first adhesive application step and the second adhesive application step.

[0008] Also, in the fiber charging step, fibers may be charged between the first adhesive application step and the first drying step. Also, in the fiber charging step, fibers may be charged between the first drying step and the second adhesive application step. Also, in the fiber charging step, fibers may be continuously charged between the first adhesive application step and the second adhesive application step. Also, in the fiber charging step, fibers may be intermittently charged between the first adhesive application step and the second adhesive application step.

[0009] Furthermore, the fiberboard according to the present invention is characterized in that wood chips and fibers are used as main raw materials, and the mixing ratio (weight %) of wood chips and fibers is 25:75 to 75:25.

[0010] Furthermore, the fiberboard manufacturing system according to the present invention includes a feeding device for performing a wood chip feeding process, a cooking device for performing a cooking process, a defibrating device for performing a defibrating process, a first adhesive coating device for performing a first adhesive coating process, a first drying device for performing a first drying process, a second adhesive coating device for performing a second adhesive coating process, a second drying device for performing a second drying process, a mat forming device for performing a mat forming process, a hot pressing device for performing a hot pressing process, and a grinding / cutting device for performing a grinding / cutting process. The system further includes a fiber feeding device for performing a fiber feeding process between the first adhesive coating process and the second adhesive coating process.

Advantages of the Invention

[0011] Since the present invention adopts the above-described means, it can provide excellent effects such as being able to provide a method for manufacturing a fiberboard that suppresses an increase in manufacturing cost.

Brief Description of the Drawings

[0012]

Figure 1

Figure 2

Figure 3

Embodiments for Carrying Out the Invention

[0013] Hereinafter, an embodiment of the manufacturing process of the fiberboard of the present invention will be described with reference to the drawings. FIG. 1 is a process diagram showing an example of the manufacturing method of the fiberboard of the present invention. The fiberboard of the present invention is manufactured in a fiberboard manufacturing system that combines various devices. The fiberboard manufacturing system includes a hopper, a wood chip feeding device such as a feeder, a cooking device such as a digester, a fiberizing device such as a refiner, a first adhesive coating device that discharges an adhesive from a nozzle installed on a pipe through which the fiber passes, a first drying device such as a flash dryer, a second adhesive coating device such as an air flow blender, a second drying device such as a flash dryer, a mat forming device such as a forming box, a hot pressing device such as a continuous press or a multi-stage press, and a device group such as a grinding / cutting device. Further, the fiberboard manufacturing system includes a fiber feeding device for feeding fibers.

[0014] With the above-described fiberboard manufacturing system, the fiberboard is manufactured through processes such as a wood chip feeding process (S1), a cooking process (S2), a fiberizing process (S3), a first adhesive coating process (S4), a first drying process (S5), a second adhesive coating process (S6), a second drying process (S7), a mat forming process (S8), a hot pressing process (S9), and a grinding / cutting process (S10). Further, in the manufacturing method of the fiberboard of the present invention, a fiber feeding process (S11a, S11b) is executed in either one or both of the period from the first adhesive coating process (S4) to the first drying process (S5) and the period from the first drying process (S5) to the second adhesive coating process (S6). Among the illustrated manufacturing processes, for the wood chip feeding process (S1), the cooking process (S2), the fiberizing process (S3), the mat forming process (S8), the hot pressing process (S9), and the grinding / cutting process (S10), it is possible to execute them by applying general techniques at the time of filing this application.

[0015] The adhesive coating processes (S4, S6) are carried out in two steps. This is for the purpose of reducing the deterioration of the adhesive in the process of drying the fibers including the wet wood chips in the cooking process (S2) and the fiberizing process (S3). That is, the first adhesive coating process (S4) emphasizes uniformly applying the adhesive, and the second adhesive coating process (S6) is the first Emphasis is placed on compensating for the deterioration of the adhesive applied in the adhesive application step (S4).

[0016] In addition, the fibers introduced in the fiber introduction steps (S11a, S11b) can mainly use fibers obtained by using waste materials. For example, the fibers to be introduced can be made of fibers that can be cut and fiberized from raw materials such as fiberized waste clothing or fiberized leather, and the material is not particularly limited as long as it is such a fiber. That is, the present invention can be applied to inventions for the purpose of recycling, and when it is for the purpose of recycling, it can be widely adopted as long as it has the property of being able to be uniformly mixed with the fibers obtained by steaming and defibrating wood chips. However, since the properties of the fibers to be introduced in the fiber introduction steps (S11a, S11b) in the present invention can be widely adopted, for example, when polypropylene is used as a material, an antioxidant may be mixed in. In this case, there is a problem that the antioxidant elutes during the process and becomes prone to ignition. However, since the fibers introduced in the fiber introduction steps (S11a, S11b) do not need to pass through the steaming step (S2) and the defibrating step (S3), it is possible to avoid the risk of being prone to ignition and combustion in this step. That is, in the present invention, it is also possible to develop in a form that ensures safety in the manufacturing process.

[0017] Incidentally, in the present embodiment, as described above, the adhesive application steps (S4, S6) and the drying steps (S5, S7) are each divided into two times. The significance is to efficiently apply the adhesive to the fibers as described above. More specifically, it is considered that the later the timing of introducing the fibers into the adhesive, the weaker the equal application property of the adhesive to the fibers. According to the current knowledge of the inventor, the timing of the fiber introduction steps (S11a, S11b) is effective from immediately after the first adhesive application step (S4) to immediately before the second adhesive application step (S6). However, the timing is not strictly limited to this, and it is not excluded even if it is from the middle of the first adhesive application step (S4) to the middle of the second adhesive application step (S6). However, it should be noted that if the second adhesive application step (S6) progresses, the curing of the adhesive progresses, making it difficult to apply the adhesive to the fibers.

[0018] The form of the method for manufacturing a fiberboard of the present invention described above can be carried out by continuous production in which all steps including the fiber introduction steps (S11a, S11b) are continuously carried out, or by batch production in which the wood chips and / or fibers are intermittently introduced for each unit amount of wood chips and / or each unit amount of fibers. Furthermore, it is possible to develop in various forms such as carrying out batch production in which some steps, for example, the fiber introduction steps (S11a, S11b) are intermittently carried out while carrying out continuous production as a whole.

[0019] In the present embodiment, in the wood chip input step (S1), the amount such as the mass and weight of the input wood chips is directly or indirectly measured, or the input of the measured unit amount of wood chips is carried out. Then, in the fiber introduction steps (S11a, S11b), an amount of fibers corresponding to the input wood chips is introduced. By controlling the input amounts of the wood chips and the fibers, it becomes possible to control the composition ratio of the wood chips and the fibers, and thereby it becomes possible to manufacture a fiberboard according to the use and purpose.

[0020] In the method for manufacturing a fiberboard according to the present invention, the adhesive is preferably a thermosetting isocyanate-based adhesive, but is not limited thereto. For example, it is possible to use a thermosetting adhesive such as a formaldehyde-based adhesive. Further, the adhesive is not limited to a thermosetting adhesive, and a thermoplastic adhesive or other adhesives that do not require heating can be appropriately selected.

[0021] As other conditions, when considering compatibility with the adhesive to be used, short fibers of uniform length are preferred, and when considering further reduction of thermal energy, it is also preferable that the fibers introduced in the fiber feeding steps (S11a, S11b) have a low moisture content.

[0022] By the above manufacturing process, the method for manufacturing a fiberboard according to the present invention has excellent effects such as being able to suppress the manufacturing cost of the fiberboard. For example, the above-described method for manufacturing a fiberboard can be applied to the method for manufacturing a fiberboard according to the present invention by using an existing manufacturing apparatus and manufacturing process. Therefore, when using waste fibers including waste materials as part of the raw materials, it is possible to efficiently manufacture a fiberboard without requiring extra and large amounts of energy, and the like, and it has excellent effects.

[0023] More specifically, in the method for manufacturing a fiberboard described above, in the steps before the fiber feeding step, the wood chips are fiberized and sufficiently dried, and waste fibers made of pre-dried waste materials are introduced into the material. Therefore, it is not necessary to repeatedly apply thermal energy to the drying process. Therefore, it is possible to avoid excessive energy consumption, and at the same time, even if the waste fibers made of waste materials contain materials dangerous to heat, it is possible to avoid the risk of ignition and fire, which can contribute to safety measures, and the like, and it has excellent effects.

[0024] Furthermore, in the method for manufacturing the fiberboard described above, the waste fiber input step may be performed between the first adhesive application step and the second adhesive application step. It may be immediately after the first adhesive application step and immediately before the first drying step, or it may be between immediately after the first drying step and immediately before the second adhesive application step. That is, it is possible to uniformly apply the adhesive as a whole regardless of the timing within these periods. Furthermore, as the waste fiber input step, a means of continuously inputting between immediately after the first drying step and immediately before the second adhesive application step was also selectively used. As a result, the adhesive can be more uniformly applied to the fibers.

Example

[0025] The test results regarding the relationship between the mixing ratio (by weight %) of wood chips and fibers and the quality of the fiberboard are described below. The following test results are those of lab test pieces manufactured using waste fibers (discarded clothing) as the fibers and using a test system.

[0026] The test conditions for creating the fiberboard are as follows.

[0027] 1. Input raw materials Wood chips: Coniferous tree fibers Fibers: Discarded clothing (polyester and cotton blended fibers)

[0028] 2. Input ratio (wood chips: discarded clothing by weight %) Comparative Example 1 100:0 Test Example 2 75:25 Test Example 3 50:50 Test Example 4 25:75 Comparative Example 5 0:100

[0029] 3. Fiberboard thickness 2.7 mm (performed at the input ratios of Test Examples 2, 3, 4, Comparative Example 1, and 5) 5.5 mm (performed at the input ratios of Test Example 3, Comparative Example 1, and 5) 12.0 mm (performed at the input ratios of Test Examples 2, 3, 4, Comparative Example 1, and 5)

[0030] The test method for fiberboard is as follows.

[0031] 1. Moisture absorption test Test piece (lab prototype): thickness [mm] × width 50 [mm] × length 300 [mm] Measurement item: length Condition: Measure the dimensional change after 72 hours under the conditions of 40°C and 90% RH, and compare with the index derived from the following formula (1). (Dimension after 72 hours - Initial dimension) / Initial dimension ··· Formula (1)

[0032] 2. Moisture desorption test (lab prototype) Test piece: thickness [mm] × width 50 [mm] × length 300 [mm] Measurement item: length Condition: Measure the dimensional change after 72 hours under the conditions of 40°C and 30% RH, and compare with the index derived from the following formula (2). (Dimension after 72 hours - Initial dimension) / Initial dimension ··· Formula (2)

[0033] 3. Bending strength test (lab prototype) Condition: Conduct the test according to the conditions specified in JIS A 5905:2022, and compare the bending strength (MOR).

[0034] The results of the moisture absorption test for samples with a fiberboard thickness of 2.7 mm are as follows. Note that LE indicates the length change rate.

[0035]

Table 1

[0036] The results of the moisture desorption test for samples with a fiberboard thickness of 2.7 mm are as follows.

[0037]

Table 2

[0038] The bending strength test results of the samples with a fiber board thickness of 2.7 mm are as follows.

[0039]

Table 3

[0040] The moisture absorption test results of the samples with a fiber board thickness of 5.5 mm are as follows.

[0041]

Table 4

[0042] The moisture desorption test results of the samples with a fiber board thickness of 5.5 mm are as follows.

[0043]

Table 5

[0044] The bending strength test results of the samples with a fiber board thickness of 5.5 mm are as follows.

[0045]

Table 6

[0046] The moisture absorption test results of the samples with a fiber board thickness of 12.0 mm are as follows.

[0047]

Table 7

[0048] The moisture desorption test results of the samples with a fiber board thickness of 12.0 mm are as follows.

[0049]

Table 8

[0050] The bending strength test results of the sample with a fiber board thickness of 12.0 mm are as follows.

[0051]

Table 9

[0052] From the above test results, in order to consider the dimensional stability based on the moisture absorption test and the moisture desorption test and ensure the strength, the mixing ratio (by weight %) of wood chips and waste fibers is preferably 25:75 to 75:25. Note that in the above comparative test, since a laboratory prototype with a high density was used, in the bending strength test results, even Comparative Example 5 has sufficient bending strength. However, when the density is reduced to the level of general market-distributed products, the bending strength may decrease by about 20%. Therefore, since sufficient strength cannot be ensured in Comparative Example 5, for the fiber board according to the present invention, the mixing ratio of wood chips and waste fibers is preferably 25:75 to 75:25.

[0053] The present invention is not limited to the embodiments described above, and can be implemented in various other forms. Therefore, the above-described embodiments are merely illustrative in all respects and should not be construed in a limiting sense. The technical scope of the present invention is defined by the claims and is not restricted by the text of the specification at all. Further, all modifications and changes belonging to the equivalent scope of the claims are within the scope of the present invention.

[0054] For example, in the above embodiment, the adhesive application step and the drying step are each shown as being carried out in two separate operations. However, the present invention is not limited to this, and it is also possible to expand to an embodiment where each is carried out once. FIG. 2 is a process diagram showing an example of the method for manufacturing a fiberboard according to the present invention. The fiberboard of the present invention is manufactured in a fiberboard manufacturing system that combines various devices. In the form of the process diagram illustrated in FIG. 2, the fiberboard manufacturing system includes a group of devices such as a wood chip feeding device, a cooking device, a defibrating device, a drying device, an adhesive application device, a mat forming device, a hot pressing device, a grinding / cutting device, etc., and further includes a fiber feeding device. And, by the fiberboard manufacturing system as described above, the fiberboard is manufactured through steps such as a wood chip feeding step (S1), a cooking step (S2), a defibrating step (S3), a drying step (S12), an adhesive application step (S13), a mat forming step (S8), a hot pressing step (S9), a grinding / cutting step (S10), etc. Further, in the method for manufacturing a fiberboard according to the present invention, a fiber feeding step (S11a, S11b) is carried out in either one or both of the period from the defibrating step (S3) to the drying step (S12) and the period from the drying step (S12) to the adhesive application step (S13). In actual implementation, it is preferable to appropriately set conditions in order to eliminate problems caused by process simplification.

[0055] Furthermore, as the fiber used as the raw material, it is possible to widely adopt fibers including various waste fibers such as fibers made from discarded clothing and fibers obtained by fiberizing discarded leather, and fibers other than waste fibers, as well as raw materials that can be cut and fiberized.

Explanation of Reference Numerals

[0056] S1 Wood chip feeding step S2 Cooking step S3 Defibrating step S4 First adhesive application step S5 First drying step S6 Second adhesive application step S7 Second drying step S8 Mat forming step S9 Hot pressing step S10 Grinding / cutting step S11a, S11b Fiber feeding step S12 Drying process S13 Adhesive application process

Claims

1. A series of steps including a step of feeding wood chips, a steaming step, a defibrating step, a first adhesive application step, a first drying step, a second adhesive application step, a second drying step, a mat forming step, a heat pressing step, and a grinding / cutting step are carried out, and a fiber feeding step is carried out between the first adhesive application step and the second adhesive application step, in which fibers obtained by fiberizing clothing or leather are fed to be mixed with the wood chips defibrated in the defibrating step. A method for producing a fiberboard comprising the steps of:

2. The fiber input step is a step of inputting fibers between the first adhesive application step and the first drying step. The method for producing a fiberboard according to claim 1 .

3. The fiber input step is a step of inputting fibers between the first drying step and the second adhesive application step. The method for producing a fiberboard according to claim 1 .

4. 2. The method for producing a fiberboard according to claim 1, wherein the fiber supply step includes supplying the fibers continuously between the first adhesive application step and the second adhesive application step.

5. 2. The method for producing a fiberboard according to claim 1, wherein the fiber supply step includes supplying the fibers intermittently between the first adhesive application step and the second adhesive application step.

6. The wood chip manufacturing method includes a series of devices including an input device that performs a wood chip input process for inputting wood chips, a steaming device that performs a steaming process, a defibrating device that performs a defibrating process, a first adhesive application device that performs a first adhesive application process, a first drying device that performs a first drying process, a second adhesive application device that performs a second adhesive application process, a second drying device that performs a second drying process, a mat forming device that performs a mat forming process, a hot pressing device that performs a hot pressing process, and a grinding and cutting device that performs a grinding and cutting process, Further, a fiber input device is provided for performing a fiber input step of inputting fibers obtained by fiberizing clothing or leather to be mixed with the wood chips defibrated by the defibrator between the first adhesive application step and the second adhesive application step. A fiberboard manufacturing system comprising:

Images