JP2006205634A - Composite plate - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a composite plate with a new constitution which hardly generates warping after manufacturing. <P>SOLUTION: The composite plate 10 is manufactured by arranging a fiber board 12 on the surface of a plywood 11 consisting of odd number of sheets of veneers 11a-11e, and laminating, sticking and integrating them. In this composite plate, fiber directions of adjoining veneers each other in the plywood intersect at right angles, and the fiber directions of the outermost surface side veneer 11a and the outermost back surface side veneer 11e approximately coincide with the longitudinal direction of the composite plate. The outermost surface side veneer 11a is thicker than the outermost back surface side veneer, and the sum of the thicknesses of the fiber board and the outermost surface side veneer is less than 50% of the whole thickness. It is preferable that the thicknesses of the second veneer and the fourth veneer are approximately the same. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a composite plate used mainly as a material for a house building member, furniture, joinery or the like.

As a conventional composite plate, for example, the one described in Patent Document 1 below is known. This composite board heat-presses the whole after placing a wood fiber board having a thickness of about 8 to 17% and a thickness of 2 mm or less with respect to the whole thickness through an adhesive on the surface of the softwood base material. It is manufactured by.
Japanese Patent No. 2530952

  When the wood fiberboard is laminated on the base material with an adhesive and stuck by hot pressure, the surface of the wood fiberboard is heated and moisture on the surface side is dissipated, so the moisture content on the surface side of the wood fiberboard Decreases. Since the wood fiber board is substantially isotropic, when the moisture content on the front surface side is lowered, a warp-like warpage or deformation with the back surface side convex is caused. In 1, the thickness of the wood fiberboard is made small, but on the other hand, it is susceptible to damage such as surface scratches and dents, and has disadvantageous disadvantages such as flatness being easily impaired. There is a risk that the constraints will increase.

  Therefore, the problem to be solved by the present invention is to provide a composite plate having a novel configuration that hardly warps after manufacture.

  In order to achieve the above object, the present invention according to claim 1 is a composite board in which fiberboards are arranged on the surface of a plywood made up of an odd number of single boards, and these are laminated and bonded together. The fiber directions of the single plates are orthogonal to each other, and the fiber directions of the outermost surface side single plate and the outermost surface side single plate substantially coincide with the longitudinal direction of the composite plate, and the outermost surface side single plate is the outermost surface side single plate. It is thicker than the plate, and the total thickness of the fiber plate and the outermost single plate is less than 50% of the total thickness.

The present invention according to claim 2 is characterized in that the thicknesses of the second single plate and the fourth single plate of the plywood are substantially the same.

  The composite board of the present invention has a fiberboard attached to the surface of a plywood, and is mainly used as a material for a house building member, furniture, joinery or the like.

  The plywood used for the composite board of the present invention is formed by laminating an odd number of single plates so that the fiber directions of adjacent single plates are orthogonal to each other. Can be used as plywood. The outermost surface side single plate and the outermost surface side single plate are arranged so as to substantially coincide with the longitudinal direction of the composite plate. Each veneer forming the plywood may be a softwood veneer or a hardwood veneer, or a plywood in which these are arbitrarily combined.

  As the adhesive interposed between the single plates or between the single plate and the fiberboard, it is preferable to use a thermosetting adhesive with less formaldehyde emission, urea resin, phenol resin, melamine resin, urethane resin or their modification. It is preferable to use one or more types arbitrarily selected from resin adhesives, isocyanate-based adhesives, synthetic rubber-based adhesives, and the like.

  The fiberboard can be selected from medium density fiberboard (hereinafter referred to as MDF) or hard fiberboard depending on the use of the composite board, and the thickness is preferably in the range of 1.0 to 4.0 mm. It can be used. When using coniferous wood as a veneer forming a plywood, a fiberboard having a relatively large (thick) thickness can be used, for example, a thickness exceeding 2.5 mm can be used. If the use of the composite board is other than flooring and the load on the surface is relatively small, use hardwood as a single board of plywood and laminate a relatively thin fiberboard on the surface For example, a fiber board having a thickness of about 1.5 mm can be used.

  About the thickness of each veneer and fiberboard forming the plywood, the outermost surface side veneer is thicker than the lowermost surface side veneer, and the total thickness of the outermost surface side veneer and the wood fiberboard is the whole composite veneer It is an essential requirement of the present invention to be less than 50% of the thickness. In addition, a plurality of (odd number) intermediate single plates sandwiched between the outermost surface side single plate and the outermost surface side single plate are symmetrical in the thickness direction (in the case of a 5-ply plywood, the second sheet from the front surface). The thickness of the single plate and the fourth single plate are preferably the same). These reasons will be described later.

The manufacturing method of the composite board of the present invention is arbitrary, and a method of forming an odd number of single boards and a laminate of fiber boards sequentially thereon with a single hot press (one-shot method), A method (kneading method) or the like in which a fiberboard is placed on the formed plywood and bonded by heat and pressure can be employed. The hot pressure is performed, for example, by pressing the laminate between two upper and lower hot platens having a flat surface, and the hot pressure conditions include, for example, hot pressure: 8 to 20 kgf / cm ² , heat The platen temperature is 110 to 150 ° C., and the hot press time is 1 to 10 minutes. Examples of specific conditions are hot press pressure: 10 kgf / cm ² , hot press plate temperature: 125 ° C., hot press time: 5 minutes. is there. Since the surface of the fiberboard that has been hot-pressed has unnecessary irregularities and scratches, the surface layer may be smoothed by grinding with a sander or a planar. Also, after forming by the above-mentioned one-shot method or kneading method using an odd number of single plates including the outermost single plate and the outermost single plate of the same thickness, the outermost single plate is formed with a sander or a planar. You may employ | adopt the manufacturing method which cuts and reduces the thickness.

  According to the first aspect of the present invention, a plywood that is a laminate of single plates and a fiberboard are used in combination, and each single plate and fiberboard in the plywood satisfy the requirements of the fiber direction and the thickness relationship described above. By this, the action of each veneer constraining and canceling the movement of each veneer shrinking and expanding in the direction perpendicular to the fiber direction is exerted, and the outermost surface side veneer of the plywood is thicker than the lowermost surface side veneer. As described later, when the pressure is released after hot pressing, both the longitudinal direction and the lateral direction have an antagonistic effect on the upper and lower warpage of the composite plate, resulting in composite It serves to substantially prevent warping of the plate. Furthermore, it is excellent in bending strength against the load that tries to bend the plywood in both the longitudinal direction and the short direction, and since the fiberboard is arranged on the surface, it is also excellent in surface smoothness, color uniformity, hardness, etc. A composite plate is obtained.

  According to the second aspect of the present invention, since the thicknesses of the second single plate and the fourth single plate in the plywood are substantially the same, the occurrence of warpage after decompression can be more effectively suppressed. it can.

  FIG. 1 is a cross-sectional view of a composite plate 10 according to an embodiment of the present invention cut along a vertical plane orthogonal to the longitudinal direction X, and FIG. 2 is a vertical plane orthogonal to the short direction Y. It is sectional drawing when cut | disconnecting. The plywood 11 in the composite plate 10 is a 5-ply plywood laminated so that adjacent single plates have a fiber direction orthogonal to each other. The first single plate (outermost surface side single plate) 11a, the third The fiber directions of the single plate 11c and the fifth single plate (the backmost single plate) 11e substantially coincide with the longitudinal direction X of the composite plate 10, and the fiber directions of the second single plate 11b and the fourth single plate 11d are composite. It substantially coincides with the short direction Y of the plate 10. A fiberboard (MDF) 12 is laminated on the surface of the plywood 11, and the single plates 11 a to 11 e in the plywood 11 and the first single plate 11 a and the MDF 12 are integrated with an adhesive to form the composite plate 10. . Although not shown, the surface of the MDF 12 can be decorated by applying a decorative sheet or painting. The size of the composite plate 10 is a product dimension, for example, width W = 303 mm, thickness T = 12 mm, and length L = 1818 mm. Since this dimension is a product dimension, it is manufactured in consideration of the compression allowance and the machining allowance due to heat pressure.

  In this embodiment, the thicknesses t1 to t5 of the single plates 11a to 11e in the plywood 11 are t1 = 1.5 mm, t2 = 2.25 mm, t3 = 1.5 mm, t4 = 2.25 mm, t5 = 1. 2 mm. That is, t1> t5 and t2 = t4 is satisfied. Further, the thickness T of the MDF 12 is 3 mm, and the total thickness (T + t1 = 4.5 mm) of the MDF 12 and the first single plate 11a is less than 50% of the total thickness of the composite plate 10 (T + t1 + t2 + t3 + t4 + t5 = 11.7 mm). ing. Further, the thickness center Z of the composite plate 10 as a whole is within the thickness range of the second single plate 11b.

  Such a composite plate 10 is hot-pressed by a method as described later, but when the pressure is released after the hot press, the first single plate 11a and the third single plate 11c whose fiber directions substantially coincide with the longitudinal direction X. And the 5th single board 11e tends to shrink | contract largely in the transversal direction Y. On the other hand, the second single plate 11b and the fourth single plate 11d, whose fiber directions substantially coincide with the short direction Y, tend to contract greatly in the longitudinal direction X. Further, the MDF 12 in which the fiber direction is non-directional tends to shrink in the longitudinal direction X and the short direction Y, but the shrinkage rate is smaller than the shrinkage rate in which the veneer tends to shrink in the direction perpendicular to the fiber direction. small. Further, the influence of the shrinkage on the warpage of the entire composite plate 10 increases as the distance from the thickness center of the composite plate 10 increases.

  Based on these assumptions, the influence of shrinkage after decompression on the warp of the composite plate 10 in the short direction Y of the composite plate 10 is examined. The third single plate 11c having the fiber direction along the longitudinal direction X is short. Although the shrinkage rate in the hand direction Y is large, it is relatively close to the thickness center Z of the composite plate 10 as a whole, so the influence on the warp of the composite plate 10 is small, and the second single plate 11b and the fourth single plate Since 11d has a fiber direction along the short direction Y, the shrinkage rate in the same direction is small. Since the thickness relationship between the first single plate 11a and the fifth single plate 11e is t1> t5 as described above, the contraction of the first single plate 11a is larger, and the plywood is warped downward (downward). However, the MDF 12 laminated and adhered to the surface of the first single plate 11a acts to suppress the contraction of the first single plate 11a. As a result, the shrinkage of the laminated portion combining the MDF 12 and the first single plate 11a is antagonized with the shrinkage of the fifth single plate 11e, and is balanced, so that the warp of the composite plate 10 is suppressed to a negligible level. be able to.

  Next, when the influence of the contraction after decompression on the warp of the composite plate 10 in the longitudinal direction X of the composite plate 10 is examined, the third single plate 11c has a small contraction rate in the longitudinal direction Y and a thickness center Z. Since the second single plate 11b has a fiber direction along the short direction Y, the contraction rate in the longitudinal direction X is large. However, since it is close to the thickness center Z of the entire composite plate, the influence on the warp is not large. Furthermore, since the first single plate 11a and the fifth single plate 11e have the fiber direction in the longitudinal direction X, the shrinkage rate in the same direction is inherently small. And the influence which the 4th single board 11d with the fiber direction along the transversal direction Y shrunk and made the composite board 10 warp, and the influence of the downward warp by shrinkage | contraction of MDF12 counteracted and balanced. Therefore, the warpage of the composite plate 10 can be suppressed to a negligible level.

  Therefore, in the composite plate 10, when the pressure is released after the hot pressing, the upper warping and the lower warping are suppressed both in the longitudinal direction X and in the lateral direction Y.

  The manufacturing method of this composite board 10 is demonstrated with reference to FIGS.

  The first manufacturing method shown in FIG. 3 is a so-called one-shot method, in which compression of heat pressure is performed on the final (finished) thicknesses T and t1 to t5 of the single plates 11a to 11e forming the MDF 12 and the plywood 11. Plates having thicknesses T ′ and t1 ′ to t5 ′ that allow for the allowance are prepared and laminated through a thermosetting adhesive to form the laminate 13. The laminated body 13 is placed on the lower heating platen 14 of the hot-pressing press and hot-pressed with the upper heating platen 15 in one step (one-shot), so that the MDF 12 and the single plates 11a to 11e The composite plate 10 is manufactured by molding so that the final thickness is T to t5.

  The second manufacturing method shown in FIG. 4 is a so-called kneading method, in which a plywood 11 composed of single plates 11a to 11e having thicknesses t1 to t5 is formed or prepared in advance, and then a thickness T is formed on the plywood 11. The composite plate 10 is manufactured by laminating the MDF 12 via a thermosetting adhesive and hot-pressure bonding.

  The third manufacturing method shown in FIG. 5 has a thickness of t5 ″ = t5 + Δt in which the final thickness t5 is calculated as the fifth single plate 11d forming the plywood 11 and the cutting allowance Δt after hot pressing is taken into account (for example, A laminated body 13 ′ is formed using t5 ″ = t1), and this is hot-pressed in one shot in the same manner as shown in FIG. Since the obtained molded body 16 has a structure in which the MDF 12 is laminated and integrated on the plywood 11 that has a shrinkage balance between the front and back surfaces, the MDF 12 serves to suppress the shrinkage of the first single plate 11a. Further, the contraction of the fifth single plate 11e becomes larger, the contraction balance is lost, and an upward warping occurs immediately after the pressure is released ((b) in the figure). In order to correct this, the back surface of the fifth veneer 11e is cut by the desired cutting allowance Δt, and its thickness is set to t5 (<t1), thereby reducing the effect of the shrinkage and balancing the front and back. The resulting composite plate 10 is free of warpage. This manufacturing method has been described on the premise of the one-shot method. However, in the kneading method shown in FIG. 4, the thickness of the fifth single plate is set to t5 ″ = t5 + Δt in consideration of the cutting allowance Δt after hot pressing. After obtaining 16, the composite plate 10 may be manufactured by cutting by the cutting allowance Δt and setting the thickness to t5 (<t1).

It is sectional drawing when the composite board by one Embodiment of this invention is cut | disconnected by the perpendicular surface orthogonal to a longitudinal direction. It is sectional drawing when this composite board is cut | disconnected by the perpendicular surface orthogonal to a transversal direction. It is explanatory drawing which shows the 1st manufacturing method of this composite board. It is explanatory drawing which shows the 2nd manufacturing method of this composite board. It is explanatory drawing which shows the 3rd manufacturing method of this composite board.

Explanation of symbols

10 Composite plate 11 Plywood 11a First single plate (outermost surface side single plate)
11b 2nd single plate 11c 3rd single plate 11d 4th single plate 11e 5th single plate (the back side single plate)
12 MDF (fiberboard)
13, 13 ′ Laminate 14 Lower hot platen 15 Upper hot platen 16 Molded body X Longitudinal direction Y of composite plate Short direction of composite plate
T MDF thickness t1 to t5 Thickness of first to fifth veneer (final thickness)

Claims (2)

In a composite plate in which fiber plates are arranged on the surface of an odd number of single plates and laminated and bonded and integrated, the fiber directions of adjacent single plates in the plywood are orthogonal to each other, and the outermost surface side unit The fiber direction of the plate and the backmost single plate is substantially coincident with the longitudinal direction of the composite plate, the topmost single plate is thicker than the backmost single plate, and the total thickness of the fiber plate and the topmost single plate is A composite plate characterized by being less than 50% of the total thickness. The composite board according to claim 1, wherein the thicknesses of the second single board and the fourth single board in the plywood are substantially the same.

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