JP2014051071A - Fiber board - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method of producing a fiber board by which the production cost of the fiber board can be reduced.SOLUTION: A complex 2 of a vegetable staple fiber and a resin is used as a binder and mixed with a vegetable filament 1 to form a vegetable filament mat, and the vegetable filament mat is molded to produce a fiber board.

Description

  The present invention relates to a fiberboard.

  The fiberboard made of vegetable long fibers is lightweight and has good strength. Therefore, a fiberboard with a surface decorative material such as an olefin sheet or a veneer is used as an interior fitting such as a door panel or a partition. .

  As a method for producing a fiberboard, it is known to produce a fiberboard by impregnating a vegetable long fiber mat with a liquid resin, drying and hot pressing (for example, see Patent Document 1). In this method, first, a vegetable long fiber mat is impregnated with a liquid resin as a binder by dipping using a resin impregnation machine. Then, if necessary, excess resin is squeezed with a squeezer. Next, the vegetable long fiber mat impregnated with the liquid resin is put into a dryer, dried and hot-pressed.

  As another method, it is known that a mixture obtained by adding a phenol-based powder adhesive as a binder to vegetable long fibers is subjected to hot pressing (for example, see Patent Document 2). In addition, it is also known to hot-press a mixture obtained by adding low melting point resin fibers as a binder to vegetable long fibers (see, for example, Patent Document 3).

JP 2009-172929 A JP 2003-260704 A JP 2003-127156 A

  However, the above-described fiberboard manufacturing method has a problem that the manufacturing cost is high. For example, a fiber sheet manufacturing method for impregnating a vegetable long fiber mat with a liquid resin uses a resin impregnation machine, but is difficult to maintain because the equipment is large and handles a large amount of liquid resin. Also, a dryer is used to dry the vegetable long fiber mat impregnated with the liquid resin, but the equipment is large and the initial investment is high. Furthermore, energy costs are high. In a fiberboard manufacturing method using a phenolic powder adhesive or a low melting point resin fiber as a binder, it is not easy to reduce the manufacturing cost because these binder materials are generally expensive.

  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 reduce the manufacturing cost of a fiber board.

  In order to solve the above-mentioned problems, the fiberboard manufacturing method of the present invention forms a vegetable long fiber mat by mixing a vegetable short fiber and a resin complex into a vegetable long fiber as a binder. A fiberboard is produced by molding a vegetable long fiber mat.

  In this fiberboard manufacturing method, it is preferable that an A-stage-shaped thermosetting resin is supplied to the vegetable short fibers, and the thermosetting resin is made into a B-stage to form the composite.

  According to the present invention, since a cheap material can be used as the composite material as a binder, the manufacturing cost of the fiberboard can be reduced.

It is explanatory drawing which showed typically the mixed state of a composite_body | complex and vegetable long fiber.

  The method for producing a fiberboard of the present invention comprises forming a vegetable long fiber mat by mixing a vegetable short fiber and a resin complex with a vegetable long fiber as a binder, and molding the vegetable long fiber mat. Manufactures fiberboard.

  The vegetable long fiber used in the present embodiment is a vegetable fiber long fiber and constitutes the main body of the fiberboard.

  Examples of plant fibers include various natural fibers. For example, fibers collected from the bast of hemp plants such as kenaf, flax, ramie, cannabis, jute, fibers collected from the stem or end of hemp plants such as Manila hemp and sisal hemp, conifers and broadleaf trees Wood fiber used as a raw material. 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. Even when the fiberboard contains moisture, the dimensional change of the fiberboard can be reduced. Therefore, when a humidity control board is incorporated as a door or a back plate, warpage and distortion can be suppressed.

  As the plant long fiber, for example, one having an average fiber length of 5 to 200 mm can be used. Also, those having an average fiber diameter of 500 μm or less can be used. By using vegetable long fibers having an average fiber length and an average fiber diameter in such a range, a fiber board with good dimensional stability can be obtained.

  The composite used as a binder is composed of vegetable short fibers and a resin.

  The vegetable short fiber used in this embodiment is a vegetable fiber short fiber. As this vegetable fiber, the same type of vegetable fiber as the above-described vegetable long fiber can be used. Also, wood fibers made from wood-based materials that are generally MDF (Medium Density Fiberboard) materials such as miscellaneous trees, woodworking scraps, waste materials, defective timbers, and thinned wood can be used. Furthermore, agricultural waste fibers made from agricultural waste such as sugar cane, corn, bamboo, and rice can be used. By utilizing such agricultural waste, it is possible to reduce waste and save valuable wood resources. Since the raw materials for the above-described wood fibers and agricultural waste fibers are inexpensive, the manufacturing cost of the fiberboard can be reduced.

  As the vegetable short fibers, for example, those having an average fiber length of less than 5 mm, more preferably 3 mm or less can be used. The lower limit of the average fiber length is not particularly limited, but can be about 0.5 mm from the viewpoint of effectively exhibiting the function of the composite as a binder. From the same viewpoint, it is desirable that the aspect ratio (length / diameter) of the vegetable short fiber is 10 or more.

  The resin used in this embodiment is a thermosetting resin. Specific examples of the thermosetting resin include urethane resin, epoxy resin, phenol resin, urea resin, melamine resin and the like. Thus, in this embodiment, various thermosetting resins can be used. Further, since a resin that can be obtained at low cost can be used, the manufacturing cost of the fiberboard can be reduced.

  Examples of the method of combining the vegetable short fiber and the resin include a method of supplying the liquid resin to the vegetable short fiber by spraying a liquid resin on the vegetable short fiber. When the liquid resin is supplied to the vegetable short fibers, the liquid resin adheres to the vegetable short fibers. The attached liquid resin is impregnated inside the vegetable short fibers or stays on the surface of the vegetable short fibers, so that the vegetable short fibers and the resin are combined. In order to uniformly adhere the liquid resin to the vegetable short fibers, a mixing device such as an air circulation pipe blender can be used. In this mixing apparatus, vegetable short fibers are allowed to flow or float in a mixing tank, and a liquid resin is sprayed onto the fibers.

  The liquid resin can be prepared using, for example, a diluent composed of an organic solvent such as ethyl acetate or toluene, or a dispersion medium such as water. Heat can be applied to form a liquid resin.

  When compounding plant short fibers and resin, for example, supplying A-stage-like thermosetting resin (liquid resin) to plant short fibers, and then converting the thermosetting resin to B-stage to form a composite May be. As a result, the composite can be easily handled in the subsequent steps, productivity can be improved, and manufacturing costs can be further reduced.

  “A stage” and “B stage” each indicate a predetermined cured state of the thermosetting resin. The thermosetting resin is called an A stage, a B stage, or a C stage depending on the curing stage. The A stage shows a cured state that is liquid or solid, is soluble in a solvent, and can be melted by heating. The A-stage thermosetting resin is positioned as a polymer precursor having a three-dimensional crosslinked structure. The B stage shows a state in which the A stage thermosetting resin is further heated to advance the curing reaction. It is also called a semi-cured state. The B-staged thermosetting resin is softened by heating and is insufficiently cross-linked as compared with the product in the C-stage state shown below. The C stage shows a state in which the B-staged thermosetting resin is further heated to complete the curing reaction.

  The compounding ratio of the resin in the composite can be, for example, in the range of 5 to 70 wt%, more preferably 10 to 50 wt% in terms of solid content in the total weight of the composite. By blending the resin within such a range, a composite that can more effectively express the function as a binder can be obtained with high productivity. Moreover, by using the composite body obtained in this way, vegetable long fibers can be efficiently bonded to each other, and a fiberboard with improved strength can be produced.

  In this embodiment, the complex and the vegetable long fiber are mixed by, for example, spraying the complex on an assembly of plant long fibers to form a plant long fiber mat. Since the main component of the composite is composed of vegetable short fibers whose length is shorter than that of plant long fibers, when the complex is sprayed on an assembly of plant long fibers, The composite is easy to enter into the voids of the long continuous fibers, and the composite is easily mixed into the aggregate of the vegetable long fibers. For this reason, as shown in FIG. 1, it is possible to disperse | distribute the composite_body | complex 2 more uniformly in the space | gap part of the assembly of the vegetable long fiber 1, and the surface of the vegetable long fiber 1. FIG. When the composite used as a binder is uniformly dispersed, the vegetable long fibers can be more efficiently bonded to each other, so that a fiberboard having good strength can be obtained.

  The mixing ratio of the composite and the vegetable long fiber is, for example, a weight ratio, for example, composite: plant long fiber = 1: 99 to 40:60, preferably 5:95 to 20:80. By setting the mixing ratio in such a range, in addition to reducing the manufacturing cost of the fiberboard by using an inexpensive material for the composite, it is possible to more firmly bond the vegetable long fibers to each other. Further, the strength of the fiberboard can be further improved.

  The vegetable long fiber mat can be formed by a known method, for example, by laminating an assembly of vegetable long fibers mixed with a composite so that the fiber direction of the vegetable long fibers is one direction. it can. After the vegetable long fiber mat is formed, pre-pressing is performed as necessary. Next, a fiberboard can be obtained by molding into a plate shape by hot pressing.

  In this molding step, the resin of the composite is melted or softened and fluidized between the surface of the vegetable long fiber of the vegetable long fiber mat and the plant long fiber. And resin is solidified (hardened), and vegetable long fibers are combined through resin. As a result, a fiberboard having good strength is obtained.

  Examples of the pressing method for hot pressing include a batch type flat plate press and a continuous press. However, there is no particular limitation, and an appropriate method can be applied. The temperature, pressure, and time of the press are appropriately set depending on the type of resin used, the thickness of the fiberboard to be obtained, and the like.

  As described above, the fiberboard manufacturing method according to the present embodiment can use an inexpensive material for the composite as a binder, and thus can reduce the manufacturing cost of the fiberboard. Since the main body is composed of vegetable short fibers whose length is shorter than that of vegetable long fibers, it is easy to mix the complex into an assembly of plant long fibers, It is possible to more uniformly disperse the composite in the voids of the aggregate of plant long fibers and the surface of the plant long fibers. Thereby, vegetable long fibers can be combined more efficiently, and the fiber board which has favorable intensity | strength can be obtained.

  In the conventional fiberboard manufacturing method, a resin impregnation machine is used to impregnate a vegetable long fiber mat with a liquid resin, and this apparatus is difficult to maintain because it handles a large amount of liquid resin. In addition, there is a problem that the dryer used in the subsequent drying process is large and the initial cost and energy cost are high. Since the fiberboard manufacturing method of this embodiment can manufacture a fiberboard without going through the impregnation step of the liquid resin into the vegetable long fiber mat and the subsequent drying step that increase the manufacturing cost in this way, Manufacturing cost can be reduced.

  The fiberboard thus produced can be made into a cosmetic material by sticking a finishing material such as a decorative sheet or a single veneer on the surface. An olefin sheet etc. can be used as a decorative sheet. As the decorative veneer, a log or a product produced by thinly slicing a laminated material in which small-corner materials are assembled and bonded can be used.

  As a method for adhering the fiberboard and the finishing material, an adhesive is applied to the fiberboard or the finishing material, and the fiberboard and the finishing material are stacked with the adhesive-coated surface inside, and hot pressing is performed with a press machine. be able to.

  The manufactured fiberboard can be suitably used for a surface material of a flash panel used for interior fittings such as a door panel, a sliding door, and a partition, or a flooring material such as a flooring floor or a staircase.

1 Plant long fiber 2 Composite

Claims (2)

  A vegetable long fiber mat is formed by mixing a composite of a vegetable short fiber and a resin into a vegetable long fiber as a binder, and the fiber long fiber mat is molded to produce a fiber board. Manufacturing method of fiberboard. 2. The method for producing a fiberboard according to claim 1, wherein an A-stage-shaped thermosetting resin is supplied to the vegetable short fibers, and the thermosetting resin is converted into a B-stage to form the composite. .