JP2019155806A - Fiber-reinforced resin composite lumber and method for suppressing lumber warp - Google Patents

Abstract

To provide composite lumber capable of suppressing lumber warp upon being dried as using wood for lumber which does not include a core part at an end surface.SOLUTION: A fiber-reinforced lumber is configured by integrating wood with its moisture percentage 20% or more and fiber-reinforced resin composite material through an adhesive.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a fiber-reinforced composite wood with suppressed warpage and a method for suppressing warpage of the wood. In particular, the present invention relates to a fiber-reinforced composite wood in which warpage generated during drying is suppressed while using undried wood, and a method for suppressing warpage of the wood.

  Wood has both the material characteristics of light weight and good workability, and the design characteristics such as healing and relaxation effects, and has been widely used in residential buildings.

  However, domestic timber is not sufficiently utilized due to higher lumbering costs than foreign timber. The reason for the high lumbering cost of domestic timber is the restriction of lumbering on the raw wood cross section during lumbering. Generally, since there is a difference between the diameter of the raw wood and the thickness suitable for lumbering, if one lumber is collected from one raw wood, the discarded portion increases and the yield during lumbering deteriorates. As a countermeasure, a method is adopted in which the raw wood is made as thick as possible, and a plurality of lumbers are collected from one raw wood. Although this method can increase the efficiency of collecting lumber and reduce the lumber cost, many of the obtained lumber do not include a core portion on the facet. The lumber that does not include a core portion on the facet tends to warp when dried, and is not suitable as it is as a building material.

  As a countermeasure against warping, a warping correction method applied in a cutting line has been proposed (Patent Document 1). However, this method does not suppress the warping of the wood itself, but corrects the warping that has occurred, and may not be able to cope with depending on the degree and direction of warping. As a method of suppressing the occurrence of warping of wood itself, a method of perforating and partially cutting a wood conduit has been proposed (Patent Document 2). However, since the drilling and cutting positions vary depending on the target wood, it is difficult to apply industrially.

  From such a background, there is a need for a method for suppressing warping of wood that can be applied industrially and uniformly without being influenced by the individuality of the target wood, and wood for which warpage is suppressed is required. It was.

Japanese Patent No. 3724681 JP 2003-276007 A

  The subject of this invention is providing the composite wood by which the curvature at the time of drying was suppressed, while using the lumber lumber whose facet does not contain a core part. Another object of the present invention is to provide a method for suppressing warping of a lumber lumber whose facet does not include a core part during drying.

The present invention is a fiber reinforced resin composite wood in which wood having a moisture content of 20% or more and a fiber reinforced resin composite material are integrated with each other through an adhesive.
The present invention also provides a fiber reinforced resin on one surface in the longitudinal direction of a wood having a moisture content of 20% or more, which is a single wood having a square cross section that does not include a core portion on the facet, and on the other surface facing the surface. It is a method for suppressing warping of a lumber lumber characterized by integrating a composite material through an adhesive.

  ADVANTAGE OF THE INVENTION According to this invention, the composite timber by which the curvature at the time of drying was suppressed can be provided, using the lumber lumber whose facet does not contain a core part. Further, according to the present invention, it is possible to provide a method for suppressing warping of wood lumber in which the facet surface does not include a core part during drying.

It is a figure explaining the fiber reinforced resin compound wood of this invention about the fore edge side and the side surface.

  Hereinafter, embodiments of the present invention will be described.

[Fiber-reinforced resin composite wood]
The fiber-reinforced resin composite wood according to the present invention is composed of undried wood having a square cross section and a fiber-reinforced resin composite material integrated with an adhesive.

  In order to effectively express the suppression of warping during drying of the wood, it is preferable that the fiber reinforced resin composite material is disposed and bonded to two opposite surfaces of the undried wood. That is, in the present invention, fibers are formed on one surface in the longitudinal direction of wood having a moisture content of 20% or more, which is a single wood having a square cross section that does not include a core portion on the facet, and on the other surface facing the surface. It is preferable to integrate the reinforced resin composite material with an adhesive. The fiber reinforced resin composite material may be bonded to the other two surfaces facing each other, that is, the surface orthogonal to these surfaces, but in this case, it is preferable to arrange and bond them on the two surfaces facing each other. In this case, the fiber reinforced resin composite material is arranged and bonded to the four side surfaces of the wood.

[wood]
As the wood, wood conventionally used as wood lumber can be used. Teak, lawan, spinal can be used. The shape of the wood is usually a shape that is cut so that the fiber direction of the wood and the long side of the wood coincide with each other.

  In order to firmly bond the wood and the fiber reinforced resin composite material, it is preferable to apply a graining process to the surface of the wood. Adhesion performance is improved by the anchor effect that the embossed part is embedded in the wood. The texture is preferably a concavo-convex process having a depth of 10 to 1000 μm on the surface of the wood.

[Fiber reinforced resin composite]
The fiber reinforced resin composite material includes reinforcing fibers and a matrix resin. This is preferably formed by a pultrusion method. The pultrusion molding method is a molding method in which reinforcing fibers are continuously drawn out and impregnated into a matrix resin and passed through a mold having a desired cross-sectional shape, for example, a square shape. According to this method, a long molded product having a uniform cross section can be continuously produced.

[Reinforcing fiber]
Examples of reinforcing fibers used in fiber reinforced resin composite materials include carbon fibers, aramid fibers, polyarylate fibers, polyparaphenylene benzobisoxazal fibers, polyphenylene sulfide fibers, polyimide fibers, tetrafluoroethylene fibers, and glass fibers. can do. Among these, it is preferable to use inorganic fibers or organic fibers having a melting point or glass transition temperature of 200 ° C. or higher. Examples of such fibers include carbon fibers, glass fibers, and aramid fibers. Of these, carbon fibers are preferable, and carbon fibers obtained from polyacrylonitrile fibers are particularly preferable. Although it is preferable to use long fibers as the reinforcing fibers, short fibers may be used together with the long fibers.

  The amount of the reinforcing fiber used is preferably 40 to 70% by volume with respect to the total volume of the fiber reinforced resin composite material. If it is less than 40% by volume, the effect of reinforcing the resin by the reinforcing fiber is reduced, which is not preferable. On the other hand, if it exceeds 70% by volume, it is difficult to uniformly impregnate the fibers with the resin, and the physical properties of the composite material are deteriorated due to stress concentration on the resin non-impregnated portion, which is a weak portion.

  As the form of the reinforcing fiber, various forms such as a UD material in which fibers are aligned in one direction, a combination of two or more directions, a woven fabric (for example, plain weave, twill weave, hybrid cloth), and a non-woven fabric can be adopted. It can be designed according to the strength. It is particularly preferable to use a UD material that is aligned in one direction from the balance between reinforcement performance and cost.

  When carbon fibers are used as the reinforcing fibers, it is preferable to use a fiber bundle (strand) composed of a single yarn having a fiber diameter of 5 to 9 μm and a constitutional number of 1000 to 300,000. These fiber bundles can be used by converging a desired amount or by expanding the sheet bundle.

[Matrix resin]
As the matrix resin used in the fiber reinforced resin composite material, either a thermoplastic resin or a thermosetting resin can be used, and a thermosetting resin is preferably used. Examples include phenol resin, epoxy resin, unsaturated polyester resin, diallyl phthalate resin, bismaleimide resin, polyimide, polyamideimide, polyurethane resin, resorcin resin, urea resin, and melamine resin.

  In the present invention, the fiber reinforced resin composite material is adhered to wood, and as a method thereof, it is usual to arrange and adhere so that the reinforcing direction of the reinforcing fiber is aligned with the fiber direction of the wood, You may use what laminated | stacked the sheet-like fiber reinforced resin composite material so that the reinforcement direction might cross | intersect as needed.

  In order to prevent warping during drying, it is desirable that the wood and the fiber-reinforced resin composite material are firmly bonded.

[Adhesion]
The adhesion is performed by laminating wood and a fiber reinforced resin composite material with an adhesive by a known method, and then, for example, under a pressure of 5 × 10 ⁵ to 15 × 10 ⁵ Pa at 20 to 40 ° C. and 5 to 24. This can be done by performing a time-tightening process.

  Examples of adhesives include resorcinol resin adhesive, resorcinol / phenol resin adhesive, aqueous polymer-isocyanate adhesive, urea resin adhesive, melamine / urea resin adhesive, phenol resin adhesive, casein wood adhesive, aqueous high A molecular-isocyanate-based adhesive, an α-olefin maleic anhydride resin adhesive, a vinyl acetate resin adhesive, or a hot melt adhesive can be used. From the viewpoint of obtaining particularly good adhesive strength, a resorcinol resin adhesive or a water-soluble polymer-isocyanate adhesive is preferable.

The amount of the adhesive used for bonding the wood and the fiber reinforced resin composite material is, for example, 100 to 400 g / m ² , preferably 200 to 250 g / m ² .

The present invention will be described in more detail with reference to examples.
(1) Warpage The sample was put into a drying furnace having an internal temperature of 65 to 85 ° C and dried for a total of 125 hours. To measure the warpage of a sample, place the sample on the floor surface, which is a flat surface, align one side in the length direction with the floor surface, and use the scale to measure the height at which the opposite side floats from the floor surface. Measured and performed. Also, the measurement was performed by measuring the height at which one side in the width direction and the floor surface were combined and the other side facing the floor was lifted from the floor surface.
(2) Moisture content Using a high-frequency moisture meter (LG6NG, manufactured by Sato Corporation), measurement was performed by bringing a spring-type sensor into contact with the wood surface.
(3) Adhesive strength Adhesive strength was evaluated by a block shear adhesion test. The sample was evaluated as “good” if the broken part in the shear test was a wood part, and “bad” if it was an adhesive layer or its interface. And when adhesion surface peeling after drying was not able to be confirmed visually, it was set as "good", and when it could be confirmed visually, it was set as "bad".
(4) Fiber Diameter The object to be measured was observed and photographed with a scanning electron microscope JSM6330F (manufactured by JEOL), 100 fibers were arbitrarily selected and measured, and the average fiber diameter was calculated. Observation and photography were performed at 1000 times.

[Example 1]
As undried wood, a fiber reinforced resin composite material using undried shiramina material (water content 40%) that is 30 mm thick × 150 mm wide × 1000 mm long and does not include a core part on the small face (30 mm × 150 mm surface) A fiber reinforced resin composite material made of a thermosetting resin containing carbon fiber continuous fibers and formed by pultrusion molding was used. The fiber reinforced resin composite material is composed of 60% by volume of carbon fiber and 40% by volume of vinyl ester resin, and the carbon fiber is aligned in one direction in a cured product of vinyl ester resin.

  As a carbon fiber, a fiber bundle oriented in one direction consisting of a single yarn fiber diameter of 7 μm and the number of constituents of 24,000 was widened into a sheet and used.

The above-mentioned fiber reinforced resin composites of thickness 0.9 mm × width 50 mm × length 1000 mm are arranged in the width direction to form a flat plate-like fiber reinforced resin composite of thickness 0.9 mm × width 150 mm × length 1000 mm. The undried cedarmina material was bonded to the upper and lower surfaces, respectively. For the adhesive, an aqueous polymer-isocyanate adhesive (manufactured by Koyo Sangyo Co., Ltd., aqueous polymer-isocyanate adhesive, main agent: KR134L curing agent: AX200) is used in an amount of 200 g / m ² , and the surface pressure is 7 The flat plate-like fiber reinforced resin composite material and the wood were adhered by subjecting the flat plate-like fiber reinforced resin composite material to a normal pressure pressing treatment at 5 × 10 ^{5 to} 10.0 × 10 ⁵ Pa for 1 hour to obtain a fiber reinforced resin composite wood. Warpage and adhesive strength were evaluated.

[Comparative Example 1]
As a sample, an undried shiramina material (water content: 40%) having a thickness of 30 mm, a width of 150 mm, and a length of 1000 mm, and having no core portion on the facet (30 mm × 150 mm) was used as it was, and the warpage was evaluated. In this comparative example, a fiber reinforced resin composite material was not used.

  According to the present invention, it is not necessary to consider warpage in the lumbering plan, and more efficient use of wood can be achieved. Furthermore, since the fiber reinforced resin composite material functions as a mechanical reinforcing layer after the wood is dried, a fiber reinforced resin composite wood with improved mechanical properties can be obtained. Since the bending is less than that of normal wood, the cross section can be reduced and the span can be increased.

1 Fiber reinforced resin composite material 2 Adhesive layer 3 Undried wood

Claims (5)

  A fiber reinforced resin composite wood in which wood having a moisture content of 20% or more and a fiber reinforced resin composite material are integrated with each other through an adhesive.   The fiber-reinforced resin composite wood according to claim 1, wherein the wood is a single wood having a square cross-section that does not include a core portion on a small face.   The fiber reinforced resin composite wood according to claim 1, wherein the fiber reinforced resin composite material is a cured product of a thermosetting resin containing inorganic fibers or organic fibers having a melting point or glass transition temperature of 200 ° C or higher.   A fiber reinforced resin composite material is bonded to one surface in the longitudinal direction of a wood having a moisture content of 20% or more, which is a single wood having a square cross section that does not include a core portion on the facet surface, and the other surface facing the surface. A method for suppressing warping of wood, characterized in that the wood is integrated.   The method for suppressing warping of wood according to claim 4, wherein the fiber reinforced resin composite material is a cured product of a thermosetting resin containing inorganic fibers or organic fibers having a melting point or glass transition temperature of 200 ° C or higher.

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