JP2015206148A - Fiber board and manufacturing method of fiber board - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a fiber board with high flexural strength with low resin ratio for bagasse fiber, and a manufacturing method of the fiber board.SOLUTION: A fiber board 1 is formed from bagasse fiber 10 and thermoplastic resin powder 20 provided as a binder at a contact point 2 of the bagasse fiber 10. The fiber board 1 is formed through: a dispersion step mixing and dispersing the bagasse fiber 10 and the thermoplastic resin powder 20 in aqueous medium at an appointed proportion; a board making and drying step making board from a mixture of the bagasse fiber 10 dispersed in the dispersion step and the thermoplastic resin powder 20 and drying the board; and a forming step forming a board of an appointed thickness by heating and compressing after the board making and drying step.

Description

  The present invention relates to a fiber board made from bagasse fiber and a method for producing the fiber board.

  Conventionally, fiber boards made from plant fibers (natural fibers) such as kenaf, bagasse, cannabis, flax, jute, sisal hemp, ramie, etc., have been used as materials for automobile interior parts. Plant fiber is known as a relatively inexpensive, light weight, and environmentally friendly material. A fiber board is made by mixing thermoplastic fiber with this plant fiber and bonding the plant fibers together. Techniques for molding the material have been proposed.

  For example, in Patent Document 1, a vegetable fiber and a thermoplastic resin fiber are mixed to form a web, and then the fibers constituting the web are entangled to form a fiber mat, and then the fiber mat is heated. A technique for producing a fiber board by compression is disclosed. According to this technique, since the vegetable fiber is crimped, the fiber mat becomes homogeneous, thereby obtaining a homogeneous fiber board.

JP 2013-36140 A

  However, in the technique of Patent Document 1 described above, since the thermoplastic resin fibers are used to join the vegetable fibers, the thermoplastic resin fibers are intensively interposed in the portion where the plant fibers are in contact with each other. Is difficult. Therefore, in order to ensure the bending strength required as a fiber board, the ratio of thermoplastic resin fibers must be increased. In other words, it is difficult to sufficiently reduce the product cost of the fiber board because the ratio of inexpensive vegetable fibers is reduced to ensure the required bending strength.

  One of the objects of the present case has been devised in view of such problems, and is to provide a fiber board having a low bending ratio and a high bending strength, and a method for manufacturing the fiber board. The present invention is not limited to this purpose, and is a function and effect derived from each configuration shown in the embodiments for carrying out the invention described later, and other effects of the present invention are to obtain a function and effect that cannot be obtained by conventional techniques. Can be positioned.

(1) The fiber board disclosed here is formed from bagasse fibers and a thermoplastic resin powder provided as a bonding material at a contact portion between the bagasse fibers.
(2) It is preferable that the fiber board is formed by drying the bagasse fiber and the thermoplastic resin powder mixed and dispersed in an aqueous medium and then drying.
(3) The thermoplastic resin powder preferably has a particle size of 10 μm or more and 100 μm or less.
(4) It is preferable that the bagasse fiber is defibrated so that the length is 10 mm or more and 80 mm or less.

  (5) The manufacturing method of the fiber board disclosed here includes a dispersion step in which bagasse fibers and thermoplastic resin powder are mixed and dispersed in an aqueous medium at a predetermined ratio, the bagasse fibers dispersed in the dispersion step, and the heat. A paper-making process for making a mixture with the plastic resin powder, a drying process for drying the mixture made in the paper-making process, and a plate having a predetermined thickness by heating and compressing after the drying process A forming step.

(6) It is preferable that the said manufacturing method is equipped with the process process which processes a thermoplastic resin pellet into the said thermoplastic resin powder whose particle size is 10 micrometers or more and 100 micrometers or less before the said dispersion | distribution process.
(7) It is preferable that the said manufacturing method is equipped with the pellet drying process which dries a thermoplastic resin pellet before the said dispersion | distribution process.
(8) It is preferable that the said manufacturing method is equipped with the fibrillation process process which makes the length of the said bagasse fiber 10 mm or more and 80 mm or less before the said dispersion | distribution process.

  According to the disclosed fiber board and the fiber board manufacturing method, the bagasse fibers can be effectively bonded to each other because the thermoplastic resin powder is intensively interposed in the contact portion between the bagasse fibers. Therefore, the disclosed fiber board can ensure a high bending strength at a low resin ratio as compared with a conventional fiber board using resin fibers as a bonding material. That is, since the ratio of inexpensive bagasse fibers can be increased while ensuring the necessary strength, the product cost of the fiber board can be reduced, and an environmentally friendly fiber board can be manufactured.

It is a mimetic diagram of a fiber board concerning one embodiment. It is the graph which showed the bending strength according to the bagasse fiber shape of the fiber board which concerns on one Embodiment. It is a photomicrograph (drawing substitute photograph) of the finished and dried product, (a) using PP powder as the bonding material, and (b) using PP fiber as the bonding material. It is the graph which showed the bending strength according to the particle size of PP powder of the fiber board which concerns on one Embodiment. It is the graph which showed the bending strength according to the resin ratio of the fiber board which concerns on one Embodiment. It is the graph which showed the bending strength according to the board density of the fiber board which concerns on one Embodiment. It is the flowchart which showed an example of the manufacturing method of the fiber board which concerns on one Embodiment.

  Hereinafter, embodiments will be described with reference to the drawings. Note that the embodiment described below is merely an example, and there is no intention to exclude various modifications and technical applications that are not explicitly described in the following embodiment. Each configuration of the present embodiment can be implemented with various modifications without departing from the spirit of the present embodiment, and can be selected or combined as necessary.

[1. Composition of fiber board]
The fiber board which concerns on this embodiment is demonstrated using FIGS. FIG. 1 is an enlarged schematic view showing a part of the fiber board 1. As shown in FIG. 1, the fiber board 1 is shape | molded from the bagasse fiber 10 and the thermoplastic resin powder 20 provided as a joining material in the contact part of bagasse fiber 10 comrades. First, the bagasse fiber 10 and the thermoplastic resin powder 20 that are raw materials of the fiber board 1 will be described.

  The bagasse fiber 10 is an example of a fiber (a fiber that can be taken from a plant, a vegetable fiber) using a plant-derived material. In addition to bagasse, plant fiber includes, for example, agricultural waste fibers such as banana, coconut, wheat, rice, corn, and pineapple, natural plant fibers such as esparto, cocoon, sabygrass, papyrus, cedar, and husk, kenaf, and jute. Cultivated plant fibers such as hemp, cocoon, cannabis, sisal hemp, and ramie. Only one type of these fibers may be used, or two or more types may be mixed and used.

  This embodiment demonstrates the case where the fiber (bagasse fiber 10) obtained from bagasse is used as vegetable fiber. Bagasse, a sugarcane pomace, is produced in large quantities as a by-product of the sugar industry, but it has few uses other than being used as a fuel in a sugar factory and is easily available in large quantities at a low price. By using this bagasse fiber 10, the fiber board 1 can be manufactured at low cost.

  The bagasse fiber 10 is fibrillated to a predetermined length before being mixed with the thermoplastic resin powder 20. Examples of the defibrating treatment include so-called beater defibrating, in which water is placed in a water tank provided with rotating wings and defibrated with rotating wings in water. Here, the result of the bending strength test of the fiber board 1 is shown in FIG. In this test, only the shape (length and diameter) of the bagasse fiber 10 was changed, and the particle size and ratio of the thermoplastic resin powder 20 and the board density of the fiber board 1 were the same. Table 1 below shows bagasse fiber shapes A, B, and C in FIG.

  As shown in FIG. 2, the bending strength of the fiber board 1 is highest when the bagasse fiber 10 having the shape B (length 10 to 80 mm, diameter 0.07 to 1 mm) is used, and then the shape A (length). The case where the bagasse fiber 10 (10-80 mm, diameter 1-8 mm) was used became high. From this result, it was found that the length of the shape of the bagasse fiber 10 greatly contributes to the bending strength of the fiber board 1. Therefore, in the present embodiment, the defibrating process is performed so that the length of the bagasse fiber 10 is 10 mm or more and 80 mm or less.

  The thermoplastic resin powder 20 functions as a bonding material that bonds the bagasse fibers 10 together. The thermoplastic resin powder 20 is mixed and dispersed with the bagasse fiber 10 in an aqueous medium to form a mixture, which is then made up. At the time of drawing up, the thermoplastic resin powder 20 concentrates on a portion where the bagasse fibers 10 are in contact with each other by a capillary phenomenon (contact portion, hereinafter referred to as an entanglement point 11). Furthermore, the finished mixture is dried, and at this time, the thermoplastic resin powder 20 is concentrated at the entanglement point 11 by capillary action.

  That is, the thermoplastic resin powder 20 is concentrated at the entanglement point 11 due to the capillary phenomenon in two stages, that is, when making (making process) and when drying (drying process), and as shown in FIG. It is intensively interposed between 11 fibers. FIG. 3 (a) shows an actual micrograph (magnification 50 times) of the mixture that has been dried and dried (hereinafter referred to as a dried and dried product). FIG. 3 (a) shows a dry-finished product in which bagasse fiber 10 is 90%, polypropylene powder (hereinafter referred to as PP powder 20) is used as thermoplastic resin powder 20, and PP powder 20 is 10%. It is. In addition, the part of the white small lump in FIG. As shown in FIG. 3A, the PP powder 20 is intensively interposed between the fibers at the entanglement point 11 of the bagasse fiber 10.

  As a comparative example, FIG. 3 (b) shows a dry-finished product in which bagasse fiber 10 is 90% and thermoplastic resin fiber (here, polypropylene fiber, hereinafter referred to as PP fiber 30) is 10%. The micrograph of is shown. The white thin linear portion in FIG. 3 (b) is the PP fiber 30. In addition, the shape and board density of the bagasse fiber 10 of Fig.3 (a), (b) are the same. As shown in FIG. 3 (b), the PP fibers 30 are dispersed in the same manner as the bagasse fibers 10, and are concentrated between the fibers at the entanglement points 11 of the bagasse fibers 10 like the PP powder 20. Not.

  The finished and dried product is heated and then compressed, further pressure-cooled and formed into a board having a predetermined thickness. During this process, the thermoplastic resin powder 20 softens and bonds the bagasse fibers 10 together. Therefore, as is clear from FIGS. 3A and 3B, the PP powder 20 intensively interposed between the fibers at the entanglement point 11 of the bagasse fiber 10 in the state of the finished and dried product is better. The bagasse fibers 10 can be firmly bonded to each other as compared with the PP fibers 30. That is, by making the thermoplastic resin used as the bonding material into powder, even if the ratio of the thermoplastic resin powder 20 is small, it effectively functions as the bonding material, and the bagasse fibers 10 can be firmly bonded to each other.

  The type of the thermoplastic resin powder 20 is not particularly limited, and for example, polypropylene, polyethylene, polystyrene, polyamide, polycarbonate, polyacetal, ABS, PLA, PBS, PET, PBT, PTT, acrylic resin, urethane resin, etc. are applicable. is there. In this embodiment, the case where PP powder 20 is used as the thermoplastic resin powder 20 will be described. The PP powder 20 is dried in a pellet state and then processed into a powder. By performing this drying process, the odor component and VOC component of polypropylene are removed. In addition, the drying process (pellet drying process) of a pellet can employ | adopt the general drying process performed in the case of injection molding, for example.

  Here, the result of the bending strength test of the fiber board 1 when the PP powder 20 having a different particle size is used as the bonding material is shown in FIG. In this test, only the particle diameter of the PP powder 20 was changed to 10 μm, 100 μm, and 1000 μm, and the shape of the bagasse fiber 10, the ratio of the PP powder 20, and the board density of the fiber board 1 were all the same.

  As shown in FIG. 4, the bending strength of the fiber board 1 was found to be higher when the particle size of the PP powder 20 was 10 μm and 100 μm than 1000 μm. This is presumably because the smaller the particle size, the higher the fluidity in the aqueous medium, and the greater the influence of the above-described capillary phenomenon (that is, the more easily concentrated at the entanglement point 11). It has also been found that the bending strength of the fiber board 1 is substantially the same when the particle size of the PP powder 20 is 10 μm and when it is 100 μm. Therefore, in this embodiment, the pellets are processed into powder so that the particle size of the PP powder 20 is 10 μm or more and 100 μm or less.

  Next, the ratio between the bagasse fiber 10 and the PP powder 20 of the fiber board 1 will be described. Here, the total of bagasse fiber 10 and PP powder 20 is 100 mass%. The fiber board 1 is used for, for example, an interior material or a part of a vehicle, and needs to have a predetermined strength according to the application. On the other hand, since the bagasse fiber 10 is inexpensive and lightweight and is an environmentally friendly material, it is preferable to make the ratio of the bagasse fiber 10 as high as possible (that is, make the ratio of the PP powder 20 as low as possible).

  Here, the relationship between the ratio (resin ratio) of the thermoplastic resin contained in the fiber board and the bending strength is shown in FIG. FIG. 5 shows the results of the bending strength test of the fiber board. Only the resin ratio contained in the fiber board was changed, and the shape and board density of the bagasse fiber 10 were the same. The black circles in FIG. 5 indicate the relationship between the resin ratio (the ratio of the PP powder 20) of the fiber board 1 formed using the PP powder 20 having a particle size of 100 μm and the bending strength. On the other hand, the white triangle mark in FIG. 5 shows the relationship between the resin ratio and the bending strength of the fiber board formed using the PP fiber 30 as the bonding material of the bagasse fiber 10 as shown in FIG. Show.

  As shown in FIG. 5, the fiber board using the PP fiber 30 as the bonding material has a high bending strength with the resin ratio being about 40 to 50%, whereas the fiber board using the PP powder 20 as the bonding material. It has been found that the board 1 already has a high bending strength when the proportion of the PP powder 20 is 20% (the proportion of the bagasse fiber 10 is 80%). As described above, since the PP powder 20 can be interposed between the fibers at the entanglement point 11 more intensively than the PP fibers 30, it effectively functions as a bonding material and strengthens the bagasse fibers 10 together. It is because it can join.

  For example, as shown in FIG. 5, when a bending strength A is required, a fiber board having a bending strength A or higher can be produced by setting the resin ratio to 20% for PP powder 20. However, with PP fibers, a fiber board with a bending strength of A or higher cannot be produced unless the resin ratio is about 45 to 50%. That is, by using the PP powder 20 as a bonding material, the ratio of the bagasse fibers 10 can be significantly increased as compared with the case where PP fibers are used. In other words, even if the ratio of the bagasse fiber 10 is increased to about 80%, the bending strength of the fiber board 1 can be increased. Therefore, in this embodiment, the ratio of the bagasse fiber 10 is 80%, and the ratio of the PP powder 20 is 20%.

Finally, the relationship between the board density and bending strength of the fiber board will be described. The board density referred to here is the mass per unit volume (ie, g / cm ³ ), and is calculated by measuring the mass and volume of the molded fiber board and dividing the mass by the volume. FIG. 6 is a graph showing the result of testing the relationship between the board density and the bending strength of the fiber board. Similar to FIG. 5, the one using PP powder 20 having a particle diameter of 100 μm as the bonding material is indicated by black circles The one using PP fiber 30 is indicated by white triangles. The resin ratio was 20% in all cases, and the shape of the bagasse fiber 10 was the same.

  As shown in FIG. 6, it was found that the fiber board 1 using the PP powder 20 as the bonding material has higher bending strength than the fiber board using the PP fiber 30 regardless of the board density. For example, as shown in FIG. 6, when the bending strength B is required, the PP powder 20 can produce a fiber board having a bending strength B or higher even if the board density is low. However, with PP fibers, a fiber board with a bending strength B or higher cannot be produced unless the board density is increased. That is, using PP powder 20 as a bonding material can reduce the weight when fiber boards having the same bending strength are formed.

  Thereby, when the fiber board 1 using the PP powder 20 as a bonding material is used as, for example, an interior material of a vehicle, the weight of the vehicle can be reduced while ensuring the required bending strength, which can contribute to an improvement in fuel consumption. . In addition, after shape | molded the fiber board 1, for example, after conveying to each factory, it heats and bends in each factory, and is shape | molded by the interior material, components, etc. of a vehicle.

[2. Manufacturing method of fiber board]
Next, the manufacturing method of the fiber board 1 which concerns on this embodiment is demonstrated using FIG. FIG. 7 is a flowchart illustrating an example of a method for manufacturing the fiber board 1. As shown in FIG. 7, first, a pretreatment process is performed (step S10). Specifically, the defibrating process is performed so that the length of the bagasse fiber 10 is 10 to 80 mm (defibrating process, step S11). Thereby, the bending strength of the fiber board 1 is increased.

  On the other hand, the polypropylene is dried in the form of pellets to remove the odor component and VOC component of the polypropylene (pellet drying step, step S15). Thereby, the quality of the product shape | molded from the fiber board 1 is improved. Then, it processes so that it may become a powder with a particle size of 10-100 micrometers (powder processing process, step S16). Thereby, the fluidity of the PP powder 20 in the paper making process and the drying process described later is secured, and the bagasse fibers 10 are firmly bonded to each other at the entanglement point 11. The defibrating process, the pellet drying process, and the powder processing process may be performed from any order, and the order thereof is arbitrary.

  Next, the bagasse fiber 10 defibrated to a predetermined length and the PP powder 20 processed to a predetermined particle size are in a predetermined ratio (here, the bagasse fiber 10 is 80% and the PP powder 20 is 20%). (Step S20). Then, the bagasse fiber 10 and the PP powder 20 are mixed and dispersed in an aqueous medium (dispersing step, step S30). When the bagasse fiber 10 and the PP powder 20 are sufficiently mixed, the mixture of the bagasse fiber 10 and the PP powder 20 is made up (paper making process, step S40). At this time, the PP powder 20 concentrates on the entanglement point 11 of the bagasse fiber 10 due to capillary action.

  Subsequently, the finished mixture is dehydrated (step S50) and dried to completely remove moisture (drying step, step S60). Also at this time, the PP powder 20 concentrates on the entanglement point 11 of the bagasse fiber 10 due to the capillary phenomenon, so that the PP powder 20 is intensively interposed between the fibers of the entanglement point 11. Then, the finished and dried product is heated and compressed by, for example, a hot press or far infrared rays (step S70), and further pressurized while being cooled (molding step, step S80). Thereby, PP powder 20 joins bagasse fiber 10 firmly. Thus, the fiber board 1 having a predetermined thickness is completed.

[3. effect]
In the fiber board 1 and the manufacturing method of the fiber board 1, the thermoplastic resin powder 20 is intensively interposed at the contact portion (that is, the entanglement point 11) between the bagasse fibers 10, so that the bagasse fibers 10 are effectively bonded together. can do. Therefore, this fiber board 1 can ensure high bending strength with a low resin ratio compared with the conventional fiber board which used the resin fiber as the joining material. That is, since the ratio of the cheap bagasse fiber 10 can be increased while ensuring the necessary strength, the product cost of the fiber board 1 can be reduced, and the environmentally friendly fiber board 1 can be manufactured. . In particular, since the fiber board 1 uses the bagasse fiber 10 as the vegetable fiber, further product cost reduction can be realized.

  The fiber board 1 is formed by mixing and dispersing the bagasse fibers 10 and the thermoplastic resin powder 20 in an aqueous medium, and then drawing the mixture and drying it. In addition, the thermoplastic resin powder 20 can enter the contact portion of the bagasse fiber 10 by capillary action in two stages, when making paper (making process) and when drying (drying process). That is, the thermoplastic resin powder 20 is concentrated at the entanglement point 11 by capillary action twice during the papermaking and drying, and between the fibers at the entanglement point 11 as shown in FIGS. Can be intensively intervened. Thereby, the bonding between the bagasse fibers 10 becomes strong, and the fiber board 1 having high bending strength can be formed even with a small amount of the thermoplastic resin powder 20.

Since the fiber board 1 is made by processing the thermoplastic resin powder 20 to have a particle size of 10 μm or more and 100 μm or less, the fluidity of the thermoplastic resin powder 20 in an aqueous medium can be improved. . Thereby, since the thermoplastic resin powder 20 is more likely to concentrate on the entanglement point 11 due to the capillary phenomenon, a high bending strength can be ensured.
Since the fiber board 1 is defibrated so that the length of the bagasse fiber 10 is not less than 10 mm and not more than 80 mm, a high bending strength can be ensured also by this.

  Furthermore, in the above fiber board 1, since the thermoplastic resin powder 20 is processed into powder after being dried in a pellet state (after passing through the pellet drying step), the odor component and the VOC component are removed from the thermoplastic resin. Can be removed. Thereby, the quality of the product obtained by processing the fiber board 1 can be improved. In particular, when the fiber board 1 is processed and used as an interior material for a vehicle, the safety and comfort of the occupant can be improved, and a comfortable vehicle interior space can be provided.

[4. Others]
Regardless of the embodiment described above, various modifications can be made without departing from the spirit of the invention. Each structure of this embodiment can be selected as needed, or may be combined appropriately.
In the said embodiment, although the bagasse fiber 10 was employ | adopted as vegetable fiber and PP powder was employ | adopted as the thermoplastic resin powder 20, the kind of vegetable fiber and the thermoplastic resin powder 20 is not restricted to these, What was illustrated above may be used, and things other than the above may be used.

  Moreover, the length of the bagasse fiber 10 is not limited to the above-described 10 to 80 mm, and the bagasse fiber 10 of less than 10 mm or the bagasse fiber 10 longer than 80 mm may be mixed. The bagasse fiber 10 may be defibrated by a method other than beater defibration, or the bagasse fiber 10 defibrated in advance may be obtained and the defibrating process may be omitted. On the contrary, there may be a processing step (for example, a cleaning process) other than the defibrating process. Further, the pellet drying step before processing into the thermoplastic resin powder 20 may be omitted by obtaining resin pellets with less odor components and VOC components in advance. Moreover, the particle size of the thermoplastic resin powder 20 is not limited to the above 10 to 100 μm, and particles larger than 100 μm or smaller than 10 μm may be mixed.

1 Fiber board 10 Bagasse fiber 11 Entanglement point (contact part)
20 PP powder (thermoplastic resin powder)
30 PP fiber

Claims (8)

Bagasse fiber,
A fiber board formed from a thermoplastic resin powder provided as a bonding material at a contact portion between the bagasse fibers. 2. The fiber board according to claim 1, wherein the bagasse fiber and the thermoplastic resin powder mixed and dispersed in an aqueous medium are formed by being made up and then dried. The fiber board according to claim 1, wherein the thermoplastic resin powder has a particle size of 10 μm or more and 100 μm or less. The fiber board according to any one of claims 1 to 3, wherein the bagasse fiber is subjected to a defibrating treatment so as to have a length of 10 mm to 80 mm. A dispersion step of mixing and dispersing bagasse fibers and thermoplastic resin powder in an aqueous medium at a predetermined ratio;
A paper making process for making a mixture of the bagasse fiber and the thermoplastic resin powder dispersed in the dispersion process;
A drying step of drying the mixture made in the paper making step;
And a forming step of forming a plate having a predetermined thickness by heating and compressing after the drying step. The method for manufacturing a fiber board according to claim 5, further comprising a processing step of processing the thermoplastic resin pellets into the thermoplastic resin powder having a particle size of 10 µm or more and 100 µm or less before the dispersing step. The method for producing a fiber board according to claim 5 or 6, further comprising a pellet drying step of drying the thermoplastic resin pellets before the dispersing step. The fiberboard manufacturing method according to any one of claims 5 to 7, further comprising a defibrating treatment step in which the length of the bagasse fiber is set to 10 mm or more and 80 mm or less before the dispersion step. .