JP5275966B2 - Manufacturing method of fiber board - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for manufacturing a fiber board by which the fiber board with a strength to be usable as a building material use or the like is efficiently and simply manufactured. <P>SOLUTION: In the method for manufacturing for keeping a mixture 1 for which a synthetic resin fiber is mixed as the binder component with a vegetable fiber heat-pressed to manufacture the fiber board 20. A low melting point synthetic resin fiber of which the melting point is lower than that of the vegetable fiber, and a high melting point synthetic resin fiber of which the melting point is higher than that of the low melting point synthetic resin fiber and is lower than that of the vegetable fiber are used as the synthetic resin fiber. Then, the mixture 1 is heated at a temperature at which the low melting point synthetic resin fiber and the high melting point synthetic resin fiber melt, and both synthetic resin fibers are molten. After the vegetable fiber is temporarily fixed to the synthetic resin fiber by cooling solidification, the mixture 1 is heat-pressed at a temperature which is lower than the melting point of the high melting point synthetic resin fiber, and at which the lower melting point synthetic resin fiber melts. <P>COPYRIGHT: (C)2011,JPO&amp;INPIT

Description

  The present invention relates to a method for manufacturing a fiber board.

  As a method for producing a fiber board in which vegetable fibers are blended, there is known a method in which a binder component of a synthetic resin is added to vegetable fibers and heated and pressed (for example, see Patent Documents 1 and 2). In order to use a fiber board as a building material, it is necessary to compress it to an appropriate specific gravity to develop strength. However, when pressing, the plant fiber that tries to push back the pressing force has a large repulsive force. There is a problem that the spring back of the vegetable fiber after the tightening pressure cannot be suppressed. In particular, when a thermoplastic resin is used as the binder component, the whole melts during heating and pressing, and the binding force between the plant fibers decreases, so that the amount of springback during opening tends to increase. In such a case, since the specific gravity of the fiber board is reduced and the strength is weakened, it is indispensable to perform cooling and pressing after heating and pressing, which increases the number of processes and manufacturing time, and is a burden on equipment.

JP 2003-127156 A Japanese Patent No. 2797922

  This invention is made | formed in view of the situation as mentioned above, and makes it the subject to provide the manufacturing method of the fiber board which can manufacture the fiber board with the intensity | strength which can be used as a building materials use etc. efficiently and simply.

  The present invention is characterized by the following.

  1stly, in the method of manufacturing a fiber board by heat-pressing the mixture which mixed the synthetic resin fiber as the binder component with the vegetable fiber, the low melting point synthetic resin fiber whose melting | fusing point is lower than a vegetable fiber as a synthetic resin fiber, And using a high melting point synthetic resin fiber having a melting point higher than that of the low melting point synthetic resin fiber and lower than that of the vegetable fiber, heating the mixture at a temperature at which the low melting point synthetic resin fiber and the high melting point synthetic resin fiber are melted. After the synthetic resin fiber is melted and the vegetable fiber is temporarily fixed to the synthetic resin fiber by cooling and solidifying, the mixture is heated and pressed at a temperature lower than the melting point of the high melting point synthetic resin fiber and the low melting point synthetic resin fiber.

  Second, in the first invention, the low melting point synthetic resin fiber has a core-sheath structure, the melting point of the sheath part is lower than the melting point of the high melting point synthetic resin fiber, and the melting point of the core part is the high melting point. A core-sheath fiber having a melting point higher than that of the synthetic resin fiber, wherein the heating temperature for heating the mixture at a temperature at which the low-melting point synthetic resin fiber and the high-melting point synthetic resin fiber are melted is lower than the melting point of the core part of the core-sheath fiber. The temperature at which the sheath portion of the fiber and the high melting point synthetic resin fiber are melted is set to a temperature at which the heating and pressing temperature of the mixture to be performed is lower than the melting point of the high melting point synthetic resin fiber and the sheath portion of the core sheath fiber is melted.

  According to the first invention, the low-melting synthetic resin fiber and the high-melting synthetic resin fiber, which are binder components, are melted and cooled and solidified, whereby the solidified synthetic resin fiber becomes a binder to bond plant fibers to each other and temporarily fix them. it can. In this state, the mixture is heated and pressed at a temperature lower than the melting point of the high-melting synthetic resin fiber and the low-melting synthetic resin fiber is melted. The plant fiber and the solidified synthetic resin fiber are bonded to each other, and the spring back of the plant fiber after the heating and pressing is effectively suppressed. Therefore, a fiber board having a strength that can be used as a building material application or the like can be efficiently and simply manufactured without cooling after heat-pressing or even with cooling for a short time.

  According to the second invention, since the core portion of the core-sheath fiber is not melted at the time of heating and pressing, the spring back of the vegetable fiber after the heating and pressing opening pressure is further effectively suppressed.

It is the figure which showed typically the manufacturing process of the fiber board for demonstrating the manufacturing method of the fiber board concerning this invention.

  The present invention has the features as described above, and the best mode for carrying out the present invention will be described below.

  In this embodiment, plant fibers are mixed with low melting point synthetic resin fibers having a melting point lower than that of plant fibers, and high melting point synthetic resin fibers having a melting point higher than that of low melting point synthetic resin fibers and lower than that of plant fibers. The mixture matted into a non-woven fabric is heated (hereinafter also referred to as “primary heating”) and once cooled, and then heated and pressed to increase the specific gravity to obtain a fiber board. The low melting point synthetic resin fiber and the high melting point synthetic resin fiber are blended as a binder component of the vegetable fiber in the fiber board, and the low melting point synthetic resin fiber and the high melting point synthetic resin fiber are melted and solidified by cooling. A fiber board having a structure in which the dimensional fibers are not easily changed due to fixing of the conductive fibers is obtained.

  In this embodiment, the most characteristic feature is that primary heating is performed at a temperature at which the low melting point synthetic resin fiber and the high melting point synthetic resin fiber are melted before the fiber mat is heated and pressed. Heating and pressing is performed at a temperature at which the low melting point synthetic resin fiber does not melt and the low melting point synthetic resin fiber melts. Both the low-melting synthetic resin fiber and the high-melting synthetic resin fiber are melted by the primary heating of the first fiber mat, and the low-melting synthetic resin fiber and the high-melting synthetic resin fiber restrain the plant fiber by the subsequent cooling and solidification. Are temporarily fixed to the synthetic resin fiber. The temporary fixing here is carried out by adhering the plant fibers to the solidified high melting point synthetic resin fiber so that the spring back of the plant fiber after opening is suppressed in the subsequent heat pressing. What is necessary is just to be fixed to the extent. In the heating and pressing, the high melting point synthetic resin fibers are not melted, and the plant fibers are constrained so that the plant fibers are bonded to the high melting point synthetic resin fibers. On the other hand, the low melting point synthetic resin fiber is remelted and hot pressed. After the heating and pressure release, the binding between the plant fiber and the high-melting synthetic resin fiber is maintained by the binding force of the high-melting synthetic resin, and the melt adhesive force of the low-melting synthetic resin fiber is also combined. The repulsive force of the vegetable fiber is suppressed, and the spring back is effectively suppressed. In addition, the high melting point synthetic resin fibers are softened by the heat at the time of heat-clamping, and change to fit the shape of the heat-clamped. It is suppressed to an equivalent thickness. For example, the heat pressing is performed by a method in which a spacer is arranged in a press machine and the fiber mat is heated and pressed to the thickness of the spacer. After heating and pressing, 5-15% of the spacer thickness is obtained. A thicker fiber board is obtained. As described above, in the present embodiment, a fiber board having a strength that can be used as a building material application or the like is efficiently and simply manufactured without cooling after heat pressing or even for a short time. be able to.

  The plant fiber used in the present embodiment is, for example, a fiber collected from the bast of a hemp plant such as kenaf, flax, ramie, cannabis, jute or the like, or a stem or end of a hemp plant such as Manila hemp or sisal hemp. Examples thereof include natural fibers such as fibers collected from muscles and wood fibers. These vegetable fibers can be used alone or in a mixture. When fibers composed mainly of hemp plants, for example, fibers of hemp plant fibers of 50% by mass or more are used in the total amount of plant fibers, the strength of fiber strength and good dimensional stability during moisture absorption are utilized. The dimensional change of the fiber board can be reduced even when the fiber board contains moisture. Therefore, when a humidity control board is incorporated as a door or a back plate, warpage and distortion can be suppressed.

  The low-melting synthetic resin fiber and the high-melting synthetic resin fiber used in the present embodiment have different melting points, and the melting point of one synthetic resin fiber may be higher or lower than the melting point of the other synthetic resin fiber. . The melting point of each synthetic resin fiber is not particularly limited as long as the melting point is lower than that of vegetable fiber, but considering the equipment for manufacturing fiber boards, the low melting point synthetic resin fiber has a melting point of, for example, 140 ° C. The following fibers are included, and it is considered that the high melting point synthetic resin fiber is composed of fibers having a melting point exceeding 140 ° C.

  Specific examples of the low melting point synthetic resin fibers include fibers of thermoplastic resins such as polyester resins and polyolefin resins. Specific examples of the high melting point synthetic resin fiber include fibers of thermoplastic resins such as polypropylene resin, polyethylene resin, polyamide resin, and polyester resin. The low-melting-point synthetic resin fiber and the high-melting-point synthetic resin fiber may be a single-component synthetic resin fiber, or a combination of a plurality of materials, for example, a fiber with a core-sheath structure in which the material of the core portion and the sheath portion is different ( (Hereinafter also referred to as “core-sheath fiber”). When using the fiber which combined the several raw material as a low melting-point synthetic resin fiber, the part should just be a synthetic resin with a low melting point. For example, when a fiber having a core-sheath structure is used as the low melting point synthetic resin fiber, a synthetic resin lower than the melting point of the core part and the high melting point synthetic resin fiber is adopted as the sheath part. The core portion is preferably a synthetic resin having a melting point higher than that of the high melting point synthetic resin fiber. When such a core-sheath structure fiber is used as the low melting point synthetic resin fiber, the primary heating temperature of the mixture is lower than the melting point of the core part of the core / sheath fiber, and the temperature at which the sheath part of the core / sheath fiber and the high melting point synthetic resin fiber melt. Then, the heating and pressing temperature of the mixture to be performed next is set to a temperature lower than the melting point of the high melting point synthetic resin fiber and the sheath part of the core-sheath fiber is melted. Since the core portion of the core-sheath fiber is not melted at the time of primary heating and heat pressing of the mixture, the plant fibers are not completely filled with the molten resin. For this reason, since the space formed between vegetable fibers is maintained, the fiber board provided with air permeability can be obtained.

  Below, the manufacturing method of a fiber board is demonstrated with reference to FIG.

  As shown in FIG. 1, a mixture 1 of plant fibers, low melting point synthetic resin fibers, and high melting point synthetic resin fibers, which have been defibrated and mixed, is continuously supplied from a hopper 2 and dispersed on a belt conveyor 3 and stacked and conveyed. And matted into a nonwoven fabric. At that time, the fibers may be conveyed to the needle punch device 4 and entangled with each other by punching with the needle 5. The needle punch device 4 is provided with a plurality of needles 5, and each needle 5 is provided with a plurality of locking claws 6 projecting from the side surface. When the mixture 1 passes through the needle punch device 4, the needle 5 A needle punch is applied by moving up and down to penetrate the mixture 1.

  After the needle punch is applied to the mixture 1, the mixture 1 is conveyed to the heating furnace 7, and the mixture 1 is subjected to primary heat treatment.

  The primary heat treatment is performed at a temperature equal to or higher than the melting points of the low-melting synthetic resin fiber and the high-melting synthetic resin fiber to melt these synthetic resins. When the molten synthetic resin is cooled and solidified, the synthetic resin serves as a binder to bond the plant fibers together, and the plant fibers are temporarily fixed to the synthetic resin. You may lightly press with the press roll 8 etc. after a primary heat processing or during a primary heat processing.

  When a core-sheath fiber having a melting point of the sheath part lower than the melting point of the high-melting point synthetic resin fiber and a melting point of the core part higher than the melting point of the high-melting point synthetic resin fiber is used as the low melting point synthetic resin fiber, The primary heat treatment is performed at a temperature lower than the melting point of the core portion of the fiber and the sheath portion of the core-sheath fiber and the high melting point synthetic resin fiber are melted.

After the heat treatment, the mixture 1 that has been conveyed to the cooling device 9 is cooled by allowing air at normal temperature to pass through and cooled, cut into a predetermined length by a cutting machine 10, and heated by a press machine 11 at a predetermined temperature ( The fiber board 20 is obtained by forming into a board state. The heating press may be a batch press or a continuous press using a roll. In order to improve the strength of the fiber board 20, it is considered that the heat pressing is performed under the condition that the specific gravity of the obtained fiber board 20 exceeds 0.5.
The heating and pressing temperature is set to a temperature lower than the melting point of the high-melting synthetic resin fiber and melting the low-melting synthetic resin fiber. In the case of using a core-sheath fiber having a melting point of the sheath part lower than the melting point of the high-melting point synthetic resin fiber and a melting point of the core part higher than the melting point of the high-melting point synthetic resin fiber as the low melting point synthetic resin fiber, The melting point is preferably lower than the melting point of the synthetic resin fiber and at a temperature at which the sheath portion of the core-sheath fiber melts.
When heat pressing is performed under these conditions, the high melting point synthetic resin fibers are not melted, and the plant fibers are bonded to each other and the plant fibers and the solidified synthetic resin fibers are bonded. And after opening pressure, since it will be in the state with which the coupling | bonding of vegetable fiber and a high melting point synthetic resin fiber is maintained, the spring back of vegetable fiber is suppressed effectively. For this reason, it is possible to efficiently and simply manufacture the fiber board 20 having a strength that can be used as a building material application or the like without performing the cooling pressing after the heating pressing or even with the cooling pressing for a short time.

  The obtained fiber board 20 has a sufficient humidity control function and strength. For example, the building material and storage in the living space such as the surface building material of the inner wall of the house, the ceiling material, the inner wall and the ceiling in the closet and the closet, etc. Can be widely used as joinery material.

  While the present invention has been described based on the embodiments, the present invention is not limited to the above-described embodiments, and various modifications can be made without departing from the scope of the invention. For example, the mixing ratio of vegetable fiber, low melting point synthetic resin fiber, and high melting point synthetic resin fiber is not particularly limited, and can be adjusted according to required strength and air permeability. Moreover, functional materials, such as a humidity control agent and a deodorizing agent, can also be mixed with a fiber board. Examples of humidity control agents include charcoal such as charcoal and bamboo charcoal, talc, zeolite, diatomaceous earth, silica minerals such as silica gel, montmorillonite and sepiolite, inorganic materials such as alumina and silica, natural materials, and polymers such as acrylic resins. A wet material etc. can be mentioned. Examples of other functional materials include charcoal powder, deodorant and antibacterial functional powder, and catalyst powder that can decompose odorous components at room temperature.

<Examples and comparative examples>
(Materials used)
-Plant fiber: Kenaf fiber-Low-melting point synthetic resin fiber: Polyester resin fiber (core-sheath structure, melting point of sheath part is 110 ° C, melting point of core part is 250 ° C)
・ High melting point synthetic resin fiber: Polypropylene resin fiber (melting point 160 ° C)
(Manufacture of fiber board)
After mixing vegetable fiber, low melting point synthetic resin fiber, and high melting point synthetic resin fiber in the proportions shown in Table 1, the mixture is needle punched, and then heated in a heating furnace set at 200 ° C. for 2 minutes (primary heating) did. After the primary heating, it was once cooled and cut, and pressed with a press machine under the following conditions. After heating and pressing, a fiber board was obtained without cooling and pressing.
Press conditions: 140 ° C., 30 kg / cm ² load, 2 minutes (1.8 mm spacer was used during pressing for a target thickness of 2.0 mm)
The finished average thickness and specific gravity of the obtained fiber board were measured to evaluate the strength of the fiber board. The acceptance criteria for strength is 15 MPa or more with reference to the fiberboard (JIS A5905) MDF15 type standard, and the substitute characteristic is a pass “○” when the specific gravity is 0.6 or more, and a failure less than 0.6 “×”. It was. The results are shown in Table 1.

  From the above results, the mixture is heated at a temperature at which the low melting point synthetic resin fiber and the high melting point synthetic resin fiber are melted, and the mixture is heated at a temperature lower than the melting point of the high melting point synthetic resin fiber and at the temperature at which the low melting point synthetic resin fiber is melted. It was confirmed that a fiber board with good strength could be obtained by tightening.

1 Mixture of vegetable fiber, low melting point synthetic resin fiber, high melting point synthetic resin fiber 20 Fiber board

Claims (2)

  In a method for producing a fiber board by heating and pressing a mixture in which a synthetic fiber is mixed with a vegetable fiber as a binder component, a low melting point synthetic resin fiber having a lower melting point than the vegetable fiber as the synthetic resin fiber, and a low melting point synthetic resin Use high-melting synthetic resin fibers that have a higher melting point than fibers and a lower melting point than plant fibers, and heat the mixture at a temperature at which the low-melting synthetic resin fibers and high-melting synthetic resin fibers melt to melt both synthetic resin fibers. And then temporarily fixing the vegetable fiber to the synthetic resin fiber by cooling and solidifying, and then heat-pressing the mixture at a temperature lower than the melting point of the high melting point synthetic resin fiber and melting the low melting point synthetic resin fiber Board manufacturing method.   The low-melting synthetic resin fiber has a core-sheath structure, the melting point of the sheath part is lower than the melting point of the high-melting synthetic resin fiber, and the melting point of the core part is higher than the melting point of the high-melting synthetic resin fiber. The heating temperature for heating the mixture at a temperature at which the low melting point synthetic resin fiber and the high melting point synthetic resin fiber melt is lower than the melting point of the core portion of the core-sheath fiber, and the sheath portion of the core-sheath fiber and the high melting point synthetic resin fiber are melted. 2. The fiber board according to claim 1, wherein the heating and pressing temperature of the mixture to be performed is lower than the melting point of the high melting point synthetic resin fiber and the sheath part of the core-sheath fiber is melted. Production method.

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