JPH10286805A - Woody composition board and its manufacture - Google Patents

Abstract

PROBLEM TO BE SOLVED: To cut a manufacturing cost to a considerably low level without deteriorating the mechanical strength while maintaining a required surface smoothness by bonding and laminating a woody fiber board which is split in hales in the thickness direction using a slicer to one face or both faces of a woody base material in such a manner that the split face sides are turned up as front face sides. SOLUTION: Woody fiber boards 1a, 1b obtained by splitting a wood in halves in the thickness direction using a slicer 10 are bonded and laminated to one face or both faces of a woody base material 2 with the help of a formalin adhesive of urea resin or an acrylic adhesive so that the split face sides are turned up as front face sides, i.e., the split face sides do not become adhesive face sides with a woody base material 2 such as a plywood, a block board, a bonded wood or a particle board. Consequently, it is possible to obtain a laminate showing excellent adhesion with the same amount of coating of an adhesive as when the wood fiber board 1 is bonded and laminated as it is to the woody base material 2. further, the laminate shows almost the same physical property value and the same surface characteristics as the laminate comprising the wood fiber board 1 bonded to the woody base material 2. Thus the wooden composite board with high strength can be obtained at a low cost by making the woody base material 2 thick.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a wood composite board and a method for producing the same, and more particularly, to a wood composite board having a wood fiber board bonded and laminated on one or both sides of a wood base material to achieve a smooth surface. It relates to the manufacturing method.

[0002]

2. Description of the Related Art A decorative wooden board in which a decorative surface layer such as a veneer or decorative paper is laminated on the surface of a wooden substrate is known and is used in a wide range of fields. Plywood, OSB as wood base material
(Oriented Strand Board), block board, glulam,
Many materials such as a particle board are used, but such a wooden base material has insufficient surface smoothness, and when a veneer or the like is stuck as it is, fine irregularities or cracks are formed on the surface of the decorative surface layer. May occur. for that reason,
Usually, some smoothing treatment is performed on the surface of the wooden base material.

As a smoothing process, typically, a surface polishing process using a wide belt sander or the like is performed.
As described in JP-A-09-09, JP-B-6-88375 and the like, a filler is applied to the surface of a wooden base material, dried, polished, and smoothed, and then an adhesive is applied and dried. Then, a process in a plurality of steps such as sticking a thin paper thereon is performed.

As another surface smoothing treatment, a thin MDF (medium fiberboard) or HDF (hardboard) is bonded and laminated on the surface of a wooden base material. MDF and H
Wood fiberboard like DF has a smooth surface from the beginning,
In addition, since it has stable surface characteristics, there is an advantage that, in addition to a simple processing step, even when a veneer or decorative paper is stuck as a decorative surface material, cracks are hardly generated on the surface. Furthermore, since there is no anisotropy, there is an advantage that the physical properties such as swelling, shrinking and bending strength have no directionality.

[0005]

SUMMARY OF THE INVENTION However, MDF
Wood fiberboards such as DF and HDF are more expensive than plywood used as a base material, and wood composite boards that have been subjected to surface smoothing treatment by sticking wood fiber boards have other surface smoothness. The cost is higher than that of wood materials that have been subjected to chemical treatment. Furthermore, in the case of MDF, MDF as a surface layer
Is sufficient if the surface smoothness can be improved,
It is empirically known that a thickness of about 1.5 mm is sufficient for this purpose, but such a thin MDF is expensive and difficult to obtain from the market.

[0006] For this purpose, a thick MDF having a thickness of about 2.5 to 5.0 mm, which is relatively inexpensive and easily available, is usually used. In order to obtain a board, it can be manufactured at low cost, but on the other hand, the base material becomes thinner by the thickness of the MDF, and when manufacturing a thin wood composite board, the strength is reduced.

The present invention is a wood composite board having a wood fiber board such as MDF or HDF adhered to the surface layer, but it is relatively inexpensive to manufacture and has the required surface smoothness. Another object of the present invention is to provide a wooden composite board and a method for manufacturing the same without reducing the mechanical strength of the wooden composite board. Another object of the present invention is to provide a wood composite board which does not cause poor adhesion (decrease in peel strength) between the wood fiber board and the wood base material, and a method for producing the same.

[0008]

A wood composite board according to the present invention for solving the above-mentioned problems basically comprises a wood fiber board provided on one or both sides of a wood base material in a thickness direction by using a slicer or the like. It is characterized in that the two parts are bonded and laminated with the divided surface side as the front side. As the wood fiber board to be used, MDF (medium fiber board) is particularly effective.
Other wood fiber boards such as (hardboard) may be used.

[0009] The present invention also provides a wood substrate in which a wood fiber board is divided into two parts in the thickness direction using a slicer or the like, and the two divided wood fiber boards are arranged such that the divided surface side is the front side. Also disclosed is a method for producing a wood composite board, characterized in that it is bonded and laminated on one side or both sides.

In the present invention, the wood substrate used is not particularly limited, and plywood, OSB, block board, laminated wood, particle board and the like can be appropriately used. Its thickness is also arbitrary. The wood fiberboard is divided into two parts in the thickness direction using a slicer or the like, so that the thickness is 1.0 to 1.0.
It is sufficient that at least one wood fiber board of about 5 mm can be obtained, and preferably a wood fiber board having a thickness of 2.5 to 5.0 mm, which is currently widely available on the market.

A wood fiber board such as MDF is produced by hot-pressing defibrated plant fibers in the presence of an adhesive, but the upper and lower surfaces in contact with the hot plate have the highest density, and the center in the thickness direction is high. The density tends to decrease toward the part. For example, for an MDF with an average density of 0.75 to 0.8,
The density of the front and back surfaces is about 0.9, and the density at the center in the thickness direction is a low value of about 0.4 in some cases.
For this reason, when the wood fiber board is divided into two parts by, for example, a slicer having a sharp flat blade, a low density layer is exposed on the divided surface. The low-density layer has more inter-fiber voids than the high-density part, and if you apply an adhesive on that surface and try to bond and laminate, the adhesive will penetrate inside the layer, resulting in sufficient adhesion I can't get the power. In order to obtain sufficient adhesive strength, a larger amount of adhesive needs to be applied.

Therefore, in the present invention, the wood fiber board divided into two in the thickness direction by using a slicer or the like is arranged so that the split surface side is the front surface side, that is, the wood fiber board is bonded to the wood substrate. It is bonded and laminated on one or both sides of the wooden base material so as not to peel off. Thus, a laminate having good adhesiveness can be obtained with the same amount of adhesive as when the wood fiber board is bonded and laminated to the wood substrate as it is.

As the adhesive to be used, an adhesive used for laminating a conventional decorative material such as a formalin-based adhesive such as a urea resin, an acrylic-based adhesive, or a urethane-based adhesive may be used as it is. There is no particular limitation on the curing type. Also, the attaching method may be the same as the conventional one.

According to the present invention, since a wood fiber board obtained by dividing a relatively thick wood fiber board which is easily and inexpensively available from the market in the thickness direction with a slicer or the like is used as a surface layer, the wood fiber board is used. The cost ratio of the wood fiber board to the base material can be reduced, and the thickness of the wood base material can be increased by the use of the thin wood fiber board, and the surface has excellent surface smoothness and high mechanical strength. Wood composite boards can be manufactured at low cost. Also, there is no possibility of poor adhesion such as a decrease in peel strength between the wood fiber board and the wood base material. Further, by providing a surface decorative layer by veneer sticking or coating on the obtained wooden composite board by a usual method, a decorative board having a flat surface without cracks can be produced.

[0015]

The present invention will be described below with reference to examples.

[Example 1] MDF1 having a thickness of 2.7 mm
By a slicer 10 of the type shown in FIGS.
It was divided into two pieces having a thickness of 1.35 mm. MD divided into two
F1a and F1b were bonded by heat and pressure to both surfaces of a 9.3 mm thick softwood plywood 2 under the following conditions so that the division surface was on the front side (that is, in an inverted state). A 12 mm wood composite board was manufactured.

Lamination conditions Adhesive: urea resin adhesive Adhesive application: roll coater Adhesive application amount: 14 g / scale ² pressing: flat plate pressing pressing pressure: 8 kgf / cm ² pressing temperature: 120 ° C. pressing Time: 90 seconds

As shown in FIGS. 1 and 2, the slicer 10 is a flat plate attached to the fixed base 11 so that the distance between the fixed base 11 and the surface of the fixed base 11 can be changed and fixed. Blades 12, upper and lower rolls 13, 13 for feeding the to-be-splied object to the blade 12 in a state of being pressed against the surface of the fixed base 11, and a feed roll 14 for sending the to-be-divided object. , And conveyers 20 and 21 for transporting the objects to be divided are arranged before and after that.

In this example, a 2.7 mm thick MDF
1 is transported on a conveyor 20 toward a slicer 10, and the blades 12 are moved by rolls 13 and 13 of the slicer 10.
Sent to The blade 12 is set at a distance of 1.35 mm from the surface of the fixed base 11 of the slicer 10, and the MDF is divided into two pieces having a thickness of 1.35 mm. The two divided MDFs 1 a and 1 b are carried out by the conveyor 21. A composite board is manufactured by attaching the two MDFs 1a and 1b to a base material (softwood plywood) 2 such that the divided surfaces of the two MDFs 1a and 1b are on the front side.

[Comparative Example 1] The MDF used in Example 1 was adhered to the front and back surfaces of a 6.6 mm thick softwood plywood in the same manner as in Example 1 without being divided into two parts. Boards were manufactured.

[Comparative Example 2] Two divided MDFs 1
a, 1b are divided by the slicer into softwood plywood 2
A wood composite board having a thickness of 12 mm was manufactured in the same manner as in Example 1 except that the laminate was directed toward the side.

[Example 2] MDF having a thickness of 3.0 mm was
The same slicer was used to divide it into two pieces having a thickness of 1.5 mm. The divided MDF was bonded to one surface of a 13.5 mm-thick OSB by cold pressure under the following conditions so that the divided surface was on the front side, to produce a wood composite board having a thickness of 15 mm.

Lamination conditions Adhesive: Honeymoon adhesive manufactured by Konishi Co., Ltd. (main adhesive: modified styrene / butadiene copolymer adhesive, primer; glyoxal) Adhesive application: roll coater Primer application: air spray Adhesive application amount: 14 g / size ² primer applied amount: 4 g / size ² pressing: flat plate pressing pressure: 5 kgf / cm ² pressing time: 30 seconds

[Comparative Example 3] A wood composite board having a thickness of 15 mm was bonded to one side of an OSB having a thickness of 12.3 mm in the same manner as in Example 2 without dividing the MDF used in Example 2 into two parts. Was manufactured.

[Comparative Example 4] Two divided MDFs 1
a, 1b are divided by the slicer into softwood plywood 2
A wood composite board having a thickness of 15 mm was manufactured in the same manner as in Example 2 except that the laminate was attached to the side.

[Evaluation Method] An impact test (DuPont impact test) according to JIS K5400 was performed on the products of Examples 1 and 2 and the products of Comparative Examples 1, 2, 3, and 4. That is, a shooting die and a cradle with a radius of 6.35 mm at the tip are arranged, the test piece is sandwiched with the surface of the test piece facing upward so that the shooting die comes to the impact point of the test piece, and a weight of 500 g is weighed. Dropped on a shooting mold from a height of 300 mm. Table 1 shows the results.

Examples 1 and 2 and Comparative Examples 1 and 2,
For 3 and 4, the surface of the MDF side was appropriately polished and smoothed, then a 0.23 mm oak veneer was pasted by a conventional method, and urethane coating was performed by a conventional method. Then 80
After two hours of standing at -20 ° C. for 2 hours, the test was repeated 10 times in a cold repetition B test, which was repeated twice, and the occurrence of cracks in the decorative layer was visually observed. Table 1 shows the results.

Examples 1 and 2 and Comparative Examples 1 and 2
With respect to 3 and 4, the arm with the caster at the tip was reciprocated a predetermined number of times while the caster was pressed against the surface of the test piece at a constant pressure, and thereafter the presence or absence of separation between the plywood (base material) and the MDF was visually observed. did. Table 1 shows the results.

The manufactured wood composite board was converted into a size of 3 ′ × 6 ′ and the material costs were compared. However, the material cost of the MDF in the case of Comparative Example 1 was set to 1, and the ratios of Examples 1, 2 and Comparative Example 3 were represented by the ratio. The values are shown in Table 2.

[0030]

[Table 1]

[0031]

[Table 2]

[Consideration] As shown in Table 1, the impact test shows almost the same results for the products of Example 1 and Comparative Examples 1 and 2 and for the products of Example 2 and Comparative Examples 3 and 4. In addition, the number of cracks generated by the repeated cold test B was the same,
The mechanical strength and surface stability of the wood composite boards obtained in the example and the comparative example are almost the same. However, in Comparative Example 2 and Comparative Example 4, separation was caused between the base material and the substrate because the divided surface by the slicer was bonded as an adhesive surface.

The products of Examples 1 and 2 are:
Since the commercially available MDF is divided into two parts, the manufacturing cost is reduced by about 20% as compared with the comparative examples (Comparative Examples 1 and 3), respectively. This shows the superiority of the manufacturing method.

[0034]

According to the present invention, a wood composite board having substantially the same physical properties and surface characteristics can be obtained at low cost. Further, in order to obtain a wood composite board having the same thickness, since the wood fiber board portion (surface layer portion) becomes thin, the wood base material can be made thicker, and a wood composite board having high strength can be obtained.
Further, a stable wood composite board can be obtained without deteriorating the releasability between the wood fiber board and the wood substrate.

[Brief description of the drawings]

FIG. 1 is a diagram illustrating a process of manufacturing a wood composite board according to the present invention.

FIG. 2 is an enlarged perspective view showing a slicer main body.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Wood fiber board (MDF), 1a, 1b ... Wood fiber board divided into two, 2 ... Wood base material, 10 ... Slicer, 11 ...
Fixed base, 12: flat blade, 13: roller, 20,
21 ... Conveyor.

Claims (4)

[Claims] 1. A wood fiber substrate obtained by dividing a wood fiber board into two in the thickness direction using a slicer or the like on one or both surfaces of a wood substrate,
A wood composite board characterized by being bonded and laminated with the divided surface side as the front side. 2. The wood composite board according to claim 1, wherein the wood fiber board is a medium fiber board. 3. A wood fiber board is divided into two parts in the thickness direction using a slicer or the like, and the two divided wood fiber boards are placed on one or both sides of a wood base such that the divided surface side is the front side. A method for producing a wooden composite board, comprising laminating and bonding a wood composite board. 4. The method for producing a wood composite board according to claim 3, wherein the wood fiber board is a medium fiber board.