JP2014151599A - Woody board - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide, by targeting a woody board using woody chips or woody fibers, a woody board having a high dimensional stability by inhibiting dimensional variations accompanying humidity absorption and release.SOLUTION: The provided woody board molded by adhering woody chips or woody fibers via an adhesive includes soft cell-removed bamboo fibers 12 obtained by removing soft cells from bamboo fibers 11 provided by pulverizing a bamboo 10.

Description

  The present invention relates to a wooden board.

  Conventionally, wood boards such as particle boards using wood chips and MDF (medium density fiber board) using wood fibers are widely used as base materials such as floor materials and wall materials used in houses and the like.

  These wood boards are generally made by mixing wood chips obtained by crushing or cutting coniferous or hardwood wood into small pieces, or bast parts of plants such as kenaf and jute, etc. This is manufactured by hot pressing.

  However, the wood board manufactured in this way has smaller elements constituting the wood board than plywood, etc., so it easily absorbs and releases moisture due to changes in the external environment such as humidity, and expands and contracts, resulting in poor dimensional stability. There was a problem.

  In order to improve the dimensional stability, the wood board using wood chips or wood fibers is placed in an autoclave and heated to treat the moisture contained in the wood board by high-pressure steaming. (See, for example, Patent Document 1).

JP 09-216206 A

  According to this proposal, although the dimensional stability of the wooden board surface layer is improved, depending on the thickness and shape of the wooden board, the high-pressure steaming treatment does not reach the core layer, so moisture absorption and desorption of the surface layer and the core layer can be prevented. There is a problem that a difference occurs in the accompanying dimensional change and the dimensional stability is not sufficiently improved.

  The present invention has been made in view of the circumstances as described above, and in a wooden board using a wooden chip or a wooden fiber, a wooden board having high dimensional stability in which dimensional changes associated with moisture absorption and release are suppressed. The issue is to provide.

  The present invention is characterized by the following in order to solve the above problems.

  That is, the wooden board of the present invention is a wooden board formed by adhering a wood chip or wood fiber with an adhesive, and contains soft cell-removed bamboo fiber obtained by removing soft cells from bamboo fiber obtained by crushing bamboo. It is characterized by doing.

  Further, in this wood board, the wood board comprises a surface layer made of the fine wood chip and a core layer made of the wood chip having a coarse mesh, and at least the surface layer contains the soft cell-removed bamboo fiber. It is preferable.

  ADVANTAGE OF THE INVENTION According to this invention, the wood board which has the high dimensional stability which suppressed the dimensional change accompanying moisture absorption / release in the wood board using a wood chip or wood fiber can be provided.

It is a schematic explanatory drawing which shows the manufacturing process of a soft cell removal bamboo fiber. It is a cross-sectional photograph which shows the structure of the three-layer particle board using a wood chip.

  Hereinafter, an embodiment of the wood board of the present invention will be described in detail. The wood board of the present invention is a wood board formed by adhering a wood chip or wood fiber with an adhesive and crushing the bamboo, and then removing the soft cells from the bamboo fibers obtained by crushing the bamboo. It is characterized by containing bamboo fiber.

  The wood board of the present invention is preferably a particle board containing a wood chip, soft cell-removed bamboo fiber and an adhesive, and MDF (medium density fiber board) containing a wood fiber, soft cell-removed bamboo fiber and an adhesive. Is preferred.

  Examples of the wood chip used for the particle board of the wood board of the present invention include, for example, wood chips made from softwood such as pine, cedar and cypress, or broad-leaved trees such as lauan, capol, and poplar, and the core of kenaf. Can do. Also, wood-based building waste can be used.

  The wood fiber used in the MDF (medium density fiber board) of the wood board of the present invention includes, for example, coniferous trees such as pine, cedar and cypress, or broad-leaved trees such as lauan, capol and poplar, decomposed at high temperature and high pressure. The wood fiber which processed the obtained wood fiber while heating and pressurizing can be mentioned.

  In the wood board of the present invention, bamboo fiber is contained in the wood chip or wood fiber. As shown in FIG. 1, first, the bamboo fiber 11 is produced by crushing the raw bamboo 10.

  Next, this bamboo fiber 11 is further coarsely pulverized and classified to produce a soft cell-removed bamboo fiber 12 from which the soft cells of the bamboo fiber 11 have been removed. The parenchyma-removed bamboo fiber 12 from which parenchyma cells have been removed is a fiber having very little dimensional change due to moisture absorption / release.

  The reason why the parenchyma cells are removed from the bamboo fibers 11 is that the parenchyma cells that firmly connect the bamboo fibers cause a dimensional change due to moisture absorption and desorption. This is because it is difficult to improve the dimensional stability even if it is contained in the composition.

  In addition, since the fiber bundle of the raw material bamboo is tightly bound to the soft cells, the soft cells are not completely removed in the state of the bamboo fiber 11 obtained by crushing the raw material bamboo. Therefore, the bamboo fibers 11 are further coarsely pulverized and classified to remove the soft cells to obtain the soft cell-removed bamboo fibers 12. The parenchyma cells are not limited to those that have been removed, and some of them may remain.

  The thickness and length of the parenchyma-removed bamboo fiber 12 from which parenchyma cells have been removed vary depending on the type of bamboo and the degree of growth of the bamboo, but are usually 10 to 100 μm in average diameter and 1.5 to 20 mm in average length. is there.

  The mixing ratio of the soft cell-removed bamboo fiber 12 is not particularly limited, but is usually in the range of 10 to 50% by mass with respect to the total amount of raw materials of the wooden board. By setting the blending amount of the soft cell-removed bamboo fiber 12 with little dimensional change due to moisture absorption / release within this range, a wood board with extremely excellent dimensional stability can be obtained.

  Further, in the production of the wood board, it is preferable that the raw material wood chips or wood fibers and the soft cell-removed bamboo fibers 12 are preconditioned to a moisture content suitable for molding.

  The wood board of the present invention is obtained by mixing the above wood chip or wood fiber and soft cell-removed bamboo fiber, adding an adhesive, mixing uniformly using a blender or the like, and heating and pressing to form a woody material. A board can be manufactured.

  As the adhesive, a synthetic resin adhesive suitable for the particle board or MDF (medium density fiberboard) to be manufactured can be appropriately selected and used.

  These include, for example, MDI (diphenylmethane diisocyanate), TDI (tolylene diisocyanate), MDI prepolymer, TDI prepolymer and other isocyanate resin adhesives, urea resin adhesives, melamine resin adhesives, urea-melamine cocondensation A resin adhesive, a phenol resin adhesive, etc. can be mentioned.

  Among these, when considering the water resistance of the wooden board and the amount of formaldehyde released causing sick house syndrome, an isocyanate resin adhesive not using formaldehyde as a raw material can be preferably used.

  The amount of the adhesive added to the particle board using the wood chip and the soft cell-removed bamboo fiber 12 is not particularly limited. For example, the total amount of the dry wood chip and the soft cell-removed bamboo fiber 12 is 100 parts by mass. It can be set to 5-15 mass parts.

  The amount of adhesive added to the MDF (medium density fiberboard) using the wood fiber and the soft cell-removed bamboo fiber 12 is not particularly limited. For example, considering the plane tensile strength, bending strength, water resistance, etc. Moreover, it can be 5-25 mass parts with respect to 100 mass parts of total amounts of the dry wood fiber and the soft cell removal bamboo fiber 12.

  Further, the wood board of the present invention can contain other additives such as wax within the range not impairing the effects of the present invention.

  In the wood board particle board of the present invention, for example, as shown in FIG. 2, a three-layer particle comprising a surface layer 21 formed of fine wood chips and a core layer 22 formed of coarse wood chips. It can be a board 20.

  Here, the meanings of the terms of fine-grained wood chips and coarse-grained wood chips used in the present invention are generally used for the surface layer and the core layer of a well-known three-layer particle board, each having a relatively different size. Specifically, the fine wood chip used for the surface layer 21 means a chip with an average length of 2 to 5 mm, and the coarse wood chip used for the core layer 22 has an average length. It means 8-20mm chip.

  When the three-layer particle board 20 having this configuration is used, at least the surface layer 21 contains the soft cell-removed bamboo fibers 12.

  In general, a single-layer particle board manufactured using only fine-grained wood chips and a single-layer particle board manufactured using only coarse-grained wood chips are particles manufactured using only fine-grained wood chips. The board has a larger dimensional change rate due to moisture absorption and desorption.

  This is because fine wood chips have a higher fiber density when used as particle boards than coarse wood chips, so the dimensional change due to moisture absorption and release of fine wood chips themselves is greater. Conceivable.

  Further, the surface layer is a layer particularly affected by humidity, and the dimensional change due to moisture absorption / release tends to increase. Therefore, it is preferable from the viewpoint of suppressing the dimensional change of the three-layer particle board 20 to include the soft cell-removed bamboo fiber 12 with very little dimensional change due to moisture absorption and release in the surface layer 21 using at least fine wood chips. .

  It should be noted that there is no problem even if the soft cell-removed bamboo fiber 12 is contained in the core layer 22 using a rough wood chip.

  According to the wood board of the present invention having the configuration of the above-described embodiment, a wood board having high dimensional stability in which a dimensional change accompanying moisture absorption / release is suppressed can be obtained.

  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, although the above embodiment has been described as the three-layer particle board 20 shown in FIG. 2, if at least the surface layer is composed of fine wood chips and soft cell-removed bamboo fibers 12, four or more layers of multi-layer particles It can be a board.

EXAMPLES Hereinafter, the present invention will be described in more detail with reference to examples. However, the present invention is not limited to these examples.
<Example 1>
As the wood board, a single-layer particle board made of a fine wood chip, soft cell-removed bamboo fiber, and an adhesive was manufactured.

  As fine particle board materials, fine wood chips (chips made by processing wood (demolition material for construction waste) to an average length of 3.5 mm), soft cell-removed bamboo fibers, and adhesives (isocyanate resin and melamine resin) Using.

  The soft cell-removed bamboo fiber is first introduced into an automatic bamboo fiber production apparatus (manufactured by Bamboo Chemical Laboratories Co., Ltd.) and bamboo fiber (average length 15 mm, average width 1.5 mm, average thickness 0. 0). 2 mm). Next, this bamboo fiber was further introduced into a fine pulverizer (manufactured by Masuno Seisakusho, New Microcyclomat) and pulverized and classified to remove parenchyma cells. Bamboo fiber removed bamboo fibers (average length 5 mm, average diameter) 60 μm) was used.

  80 parts by mass of the above-mentioned fine wood chips, 20 parts by mass of soft cell-removed bamboo fibers, and 5 parts by mass of each adhesive were put into a high-speed mixer and mixed to prepare a particle board forming mixture.

Next, the prepared particle board forming mixture was pre-compressed and then subjected to hot pressing under conditions of 180 ° C. and 40 kg / cm ² , and a particle board having a length and width of 300 × 300 mm and a thickness of 12 mm was manufactured through a finishing process.
<Example 2>
Except that the fine wood chip used in Example 1 was changed to a coarse wood chip (chip obtained by processing wood (demolition material for building waste) into an average length of 12 mm), the same as in Example 1. Manufactured particle board.
<Comparative Example 1>
Bamboo fiber (average length 15 mm, average width 1) obtained by introducing bamboo raw material into an automatic bamboo fiber creation device (manufactured by Bamboo Chemical Laboratory Co., Ltd.) instead of the soft cell-removed bamboo fiber used in Example 1 A particle board was manufactured in the same manner as in Example 1 except that 0.5 mm and an average thickness of 0.2 mm were used.
<Comparative example 2>
A particle board was produced in the same manner as in Example 2 except that the bamboo fiber of Comparative Example 1 was used instead of the soft cell-removed bamboo fiber used in Example 2.
<Comparative Example 3>
A particle board was produced in the same manner as in Example 1, except that the soft cell-removed bamboo fiber used in Example 1 was not contained, and the compounding amount of fine wood chips was 100 parts by mass.
<Comparative example 4>
A particle board was produced in the same manner as in Example 2, except that the soft cell-removed bamboo fiber used in Example 2 was not contained, and the blending amount of the coarse wood chips was 100 parts by mass.
[Dimensional change rate during moisture absorption / release]
The length change rate and thickness change rate at the time of moisture absorption / release of each particle board manufactured in Examples 1 and 2 and Comparative Examples 1 to 4 were determined. After making constant weight at 20 ° C. and 60% RH, make constant weight at 40 ° C. and 90% RH, measure the dimensional change in the plane direction at that time to obtain the length change rate, and measure the dimensional change in the thickness direction. The thickness change rate was obtained. The results are shown in Table 1.

  From Table 1, the particle boards of Examples 1 and 2 containing soft cell-removed bamboo fibers absorb and release both in length and thickness compared to the particle boards of Comparative Examples 1 to 4 that do not contain soft cell-removed bamboo fibers. It was confirmed that the dimensional change rate due to moisture was small, and the soft cell-removed bamboo fiber suppressed dimensional change due to moisture absorption and desorption.

  In addition, from the comparison of Examples 1 and 2 containing soft cell-removed bamboo fiber and Comparative Examples 1 and 2 containing bamboo fiber, by containing the soft cell-removed bamboo fiber from which bamboo soft cells were removed, It was confirmed that dimensional changes due to moisture absorption and desorption can be suppressed.

  From these results, it is possible to obtain a wooden board having high dimensional stability by suppressing the dimensional change due to moisture absorption and desorption, by including the soft cell-removed bamboo fiber from which the bamboo soft cells have been removed in the wooden board. Was confirmed.

DESCRIPTION OF SYMBOLS 10 Bamboo 11 Bamboo fiber 12 Soft cell removal bamboo fiber 20 3 layer particle board 21 Surface layer 22 Core layer

Claims (2)

  A wooden board formed by bonding a wood chip or a wood fiber with an adhesive, and comprising a soft cell-removed bamboo fiber obtained by removing soft cells from bamboo fiber obtained by crushing bamboo. The said wooden board consists of the surface layer which consists of the said fine wood chip | tip with a fine grain, and the core layer which consists of the said fine wood chip | tip, and at least the said surface layer contains the said soft cell removal bamboo fiber. Woody board described in.