JP4185915B2 - Composite plate manufacturing method - Google Patents

Description

  The present invention relates to a method of manufacturing a composite plate mainly used as a material for a member for home building, 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 stacked 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 reduced, a warp-like warp 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 suppress warping in the composite plate after manufacture, and to provide a novel manufacturing method therefor.

In order to solve the above-mentioned problems, the present invention according to claim 1 is directed to the back surface side veneer in which the fiber direction substantially coincides with the longitudinal direction and the moisture content is 1 to 5%, and the fiber direction is the longitudinal direction. A plurality of intermediate veneers that substantially coincide with each other in the direction orthogonal to the outermost side veneer, and the fiber surface is substantially coincident with the longitudinal direction and the moisture content is 6 to 16%. After laminating via an adhesive and further laminating a fiber board via this adhesive on the outermost surface side veneer, the resulting laminated body is integrated by hot pressure, so that the lowermost surface side veneer The total thickness of the fiberboard and the outermost surface side veneer is less than 50% of the total thickness of the composite plate. This is a method for manufacturing a composite plate. The composite board manufactured by the present invention is mainly used as a material for a member for home building, furniture, joinery and the like.

  In the present invention, a laminate composed of an outermost surface single plate, an outermost back surface single plate and a plurality of intermediate single plates, that is, a plywood having 4 plies or more, is used. The backmost single plate) has a fiber direction substantially coincident with the longitudinal direction of the plywood (or composite plate), and a plurality of single plates (intermediate single plates) positioned between the front and back single plates are the longitudinal direction of the plywood. The fiber direction substantially coincides with the direction orthogonal to the width direction (that is, the short direction or the width direction). By using a plurality of intermediate veneers, the defects of each veneer are dispersed, and the local lack of strength can be solved. Each veneer forming the plywood may be a softwood veneer or a hardwood veneer. The longitudinal direction means a direction along the longer side of the two adjacent sides of the composite plate in the plan view rectangle, and the direction along the shorter side is the short direction. In the case of a square in plan view, one of the two adjacent sides is the longitudinal direction and the other is the short direction.

  The thickness of the outermost single plate is equal to or greater than the thickness of the outermost single plate in the laminated state after hot pressing. As an example, the thickness of the outermost single plate and the intermediate single plate may be the same, and the outermost single plate may be the same or thicker than these. The thicknesses of the outermost single plate and the outermost single plate satisfy the above relationship and are preferably in the range of 1.0 to 3.0 mm, for example, 2.0 mm. If the thickness is less than 1.0 mm, it is too thin to make the production difficult. If these thicknesses exceed 3.0 mm, the thickness when a plurality of sheets are laminated increases and the weight becomes excessive, and it is uneconomical under the depletion of wood resources.

  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 2.0 to 5.0 mm. It can be used. If the thickness of the fiberboard is less than 2.0 mm, it will be too thin and it will be susceptible to the transfer of the grain pattern of the veneer and surface scratches, and the effect of suppressing the shrinkage and expansion of the outermost veneer will be insufficient. It becomes impossible to prevent the composite plate from warping. When the thickness of the fiber board exceeds 5.0 mm, shrinkage and expansion accompanying the change in the moisture content of the fiber board itself increases, and the balance of warpage as a composite board tends to be lost.

  Each single board and fiber board which satisfy | filled said requirements are laminated | stacked sequentially through an adhesive agent. 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.

  When forming a laminated body, the moisture content of the outermost surface side single plate is made larger than the moisture content of the outermost surface side single plate. Specifically, the moisture content of the outermost single plate is 6 to 16%, and the moisture content of the outermost single plate is 1 to 5%. When the moisture content of the outermost single plate exceeds 16%, the shrinkage rate after hot pressing increases and the composite plate tends to warp, and when it is less than 6%, the shrinkage rate after hot pressing decreases. As a result, the composite plate tends to warp. When the moisture content of the backmost single plate exceeds 5%, the shrinkage rate after hot pressing increases, and the composite plate tends to warp. When it is less than 1%, the shrinkage rate after hot pressing decreases. Thus, the composite plate tends to warp. As a preferred example, the moisture content of the outermost single plate is about 12%, and the moisture content of the outermost single plate is about 4%.

The laminated body laminated | stacked through the adhesive agent is shape | molded and integrated by one time (one shot) hot pressure, and a composite board is obtained. The hot pressing is performed by, for example, hot pressing with a laminated body sandwiched between two upper and lower hot pressing plates having a flat surface. The hot pressure conditions are, for example, hot pressure pressure: 8 to 20 kgf / cm ² , hot platen temperature: 110 to 150 ° C., and hot pressure time: 1 to 10 minutes. The optimum conditions are selected according to the type of fiberboard and the thickness of these. 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.

  According to the first aspect of the present invention, the fiberboard, the outermost surface side single plate, and the outermost surface side single plate provided on the outermost surface of the composite plate are separated from the thickness center of the composite plate. Greatly affects the warpage of the composite plate. Here, since the moisture content of the outermost single plate is larger than the moisture content of the outermost single plate, after hot pressing, the outermost single plate tends to shrink more than the outermost single plate. Since the thickness of the veneer is equal to or greater than the thickness of the outermost single plate, the outermost single plate resists the contraction / expansion of the outermost single plate, and the outermost single plate Suppresses shrinkage and expansion. Further, the fiberboard bonded to the surface exerts a restraining force against the expansion / contraction of the outermost surface side single plate. As a result of these, the shrinkage / expansion of the fiberboard and the outermost single plate on the front surface side of the composite plate and the shrinkage / expansion of the outermost single plate on the rear surface side each other, and a composite plate that is unlikely to warp is obtained. .

  When there are two intermediate single plates, the thickness of the fiber plate is increased to some extent within the range of 2.0 to 5.0 mm, and the total thickness of the fiber plate and the outermost single plate is the total thickness of the composite plate By setting it to less than 50%, the thickness center of the composite plate as a whole can be within the thickness range of the upper intermediate single plate, thereby minimizing the warpage of the composite plate to an almost negligible level. . Further, by using a relatively thick fiberboard, it is possible to improve the surface smoothness of the composite board, scratch resistance and durability against surface scratches and dents, bending strength, and the like.

  The best mode for carrying out the present invention will be described below with reference to the accompanying drawings.

  1 and 2 show an example of a composite plate manufactured by the method of the present invention. FIG. 1 is a cross-sectional view taken along a vertical plane along the lateral direction Y, and FIG. It is sectional drawing when cut | disconnecting by a surface. This composite board 10 is used as a floor board for residential buildings. From the back side, the back side single board 11, the two intermediate single boards 12 and 13, the top side single board 14 and the MDF 15 are adjacent to each other. The layers are laminated via an adhesive and are molded and integrated by hot pressure.

The fiber directions of the outermost single plate 11 and the outermost single plate 14 substantially coincide with the longitudinal direction X of the composite plate 10, and the fiber directions of the intermediate single plates 12 and 13 are substantially equal to the short direction Y of the composite plate 10. I'm doing it. The thickness t ₁ of the outermost single plate 11 is equal to or greater than the thickness t ₄ of the outermost single plate 14. In this embodiment, t ₁ = t ₄ = 2.0 mm. Has been. Further, the thickness T of the MDF 15 is 2.2 mm, the thicknesses t ₂ and t ₃ of the intermediate single plates 12 and 13 are both 2.0 mm, and the total thickness T ₀ of the composite plate 10 is 10.2 mm. Therefore, the thickness center Z of the composite plate is in the upper intermediate single plate (third single plate) 13. The total thickness of the MDF 15 and the outermost surface side single plate 14 is T + t ₄ = 4.2 mm, which is less than 50% of the total thickness of the composite plate T ₀ = 10.2 mm.

A method for manufacturing the composite plate 10 will be described with reference to FIG. First, on the lower hot platen 16, a backmost single plate 11 having a fiber direction substantially coincident with the longitudinal direction X, and two intermediate veneers 12 and 13 having a fiber direction substantially coincident with the short direction Y. Then, the outermost surface side veneer 14 and the MDF 15 having a fiber direction substantially coincident with the longitudinal direction X are sequentially laminated via a urea melamine resin adhesive (not shown). At this time, the moisture content of the outermost back side veneer 11 is 4%, and the moisture content of the outermost surface side veneer 14 is 12%. The thicknesses t ₁ ′ to t ₄ ′ and T ′ of each plate before hot pressing are about 5% with respect to these so that the final plate thickness after hot pressing becomes the above t ₁ to t ₄ and T, respectively. It is set as the thickness considering the compression allowance.

In this way, after the laminated body 18 in which the single plates 11 to 14 and the MDF 15 are sequentially laminated via the adhesive is placed on the lower hot platen 16, the upper hot platen 17 is lowered to lower the lower platen. The heat pressure is integrated between the hot platen 16 and the upper hot platen 17. This hot pressure is performed once (one shot). For example, a hot pressure condition of pressure: 10 kgf / cm ² , hot platen temperature: 125 ° C., and hot pressure time: 5 minutes is adopted. After hot pressing, after curing, cut into specified dimensions. Since there are unnecessary irregularities and scratches on the front and back surfaces of the composite plate 10 that has been hot-pressed, the front and back layers are shaved with a sander or a planer as necessary. In this case, the finished thickness after shaving satisfies the above relationship (t ₁ ≧ t ₄ , (T + t ₄ ) <(T ₀ × 50%)).

  In this way, 20 300 mm × 300 mm square composite plates 10 were manufactured under the same conditions, left for 24 hours after hot pressing, and then the warpage was measured and the average value of 20 was taken. Was 300 mm in length and 0.2 mm in concave warp, and in the lateral direction Y, 300 mm in length and 0.2 mm in concave warp was observed. The amount of warpage in the longitudinal direction X is determined by applying a straight ruler along the longitudinal direction X so as to pass the center point (intersection of diagonal lines) of the composite plate 10, and the distance between the straight ruler and the surface of the composite plate 10 at the center point (warpage amount). ) Was measured. Similarly, the amount of warpage in the short direction Y is determined by applying a straight ruler along the short direction Y so as to pass through the center point (intersection of diagonal lines) of the composite plate 10, and the straight ruler at the center point and the surface of the composite plate 10. The measurement was performed by measuring the interval (the amount of warping).

  As a comparative example, 20 test plates were produced under the same conditions as in the above example except that the moisture content of the outermost surface side veneer 14 was set to 12%, the same as the moisture content of the outermost surface side veneer 11. Then, when the average value of the warpage amount was taken, a concave warp of 1.3 mm with a length of 300 mm was observed in the longitudinal direction X, and a convex warp of 0.7 mm with a length of 300 mm was observed in the short direction Y.

  That is, the composite board 10 manufactured by the method of the present invention satisfies the above-described requirements of the thickness relation and the water content magnitude relation, so that the MDF 15 and the outermost-surface single board 14 tend to contract and expand on the surface side. Whereas the movement and the movement of the outermost single plate 11 that shrinks and expands on the rear surface side are antagonizing and suppressing the warpage, in the test plate of the comparative example, the outermost surface side single plate 14 and the outermost surface side Since the moisture content of the veneer 11 is the same and does not satisfy the requirements for the magnitude relationship of the moisture content, the movement of contraction / expansion does not antagonize between the front surface side and the back surface side, resulting in a large warp. The warpage of the composite plate of the embodiment of the present invention is 1/6 or less in the longitudinal direction X and 1/3 or less in the lateral direction Y, compared to the warpage of the test plate of the comparative example, and is excellent in warpage prevention. It was proved that the effect was obtained.

It is sectional drawing when an example of the composite board manufactured by the method of this invention is cut | disconnected by the perpendicular surface along the transversal direction Y. FIG. 2 is a cross-sectional view of the composite plate when cut along a vertical plane along the longitudinal direction X. FIG. It is explanatory drawing which shows the manufacturing process of this composite board.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Composite board 11 Outermost back side single board 12, 13 Intermediate single board 14 Outermost surface side single board 15 MDF
16 Lower hot platen 17 Upper hot platen 18 Laminate X Longitudinal direction Y of composite plate Short side direction of composite plate Z Thickness center line of composite plate

Claims (1)

A plurality of intermediate veneers in which the fiber direction substantially coincides with the direction perpendicular to the longitudinal direction is bonded on the backmost single plate having the fiber direction substantially coincident with the longitudinal direction and the water content is 1 to 5%. And the outermost surface side veneer whose fiber direction is substantially coincident with the longitudinal direction and having a moisture content of 6 to 16% is laminated on the outermost surface side veneer by using an adhesive. Furthermore, after laminating the fiberboard via an adhesive, the thickness of the backmost single plate is approximately equal to the thickness of the topmost single plate by integrating the obtained laminate by heat pressure or A method for manufacturing a composite plate, characterized in that the total thickness of the fiber plate and the outermost surface side single plate is less than 50% of the total thickness of the composite plate.

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