JP7171299B2 - COMPOSITE MATERIAL AND METHOD FOR RECOVERING BASE MATERIAL FROM COMPOSITE - Google Patents

Description

TECHNICAL FIELD The present invention relates to a composite material of wood used as a building material, and more particularly to a composite material reinforced with a fiber-reinforced resin member to remarkably improve bending performance.

Laminated lumber obtained by laminating a single piece of wood, lamina cut long in the fiber direction of the wood, or small square lumber with the fiber direction parallel to each other with an adhesive, is used in construction for columns and beams. It is also used as a structural material for wooden bridges and large domes.

Laminated lumber is made by laminating sawn boards and small square lumber, so it has a high degree of freedom in terms of size and shape. It has excellent properties.

However, when laminated lumber is used for a large-scale building or structure, it is necessary to increase the rigidity and strength of the laminated lumber, so the cross-sectional height of the laminated lumber must be increased. For this reason, there is a problem that the ceiling height of buildings and structures must be set low, and a problem that designability is impaired. In order to solve this problem, it has been proposed to use a fiber-reinforced laminated timber in which reinforced fibers that are lightweight and have high rigidity and strength are adhered to the laminated timber via an adhesive.

For example, Patent Literature 1 discloses a fiber-reinforced laminated lumber containing belt-shaped reinforcing fibers thinly spread by fiber opening between layers of a wooden material. However, this invention requires the use of "fibers thinly spread by the fiber opening process" in order to emphasize adhesive strength, and specifically, it is premised on suppressing the thickness of the fiber layer to several tens of μm. It is a technology that makes This is because it was thought that the adhesiveness would decrease when the fiber layer was thick (Patent Document 1, Section [0029]). However, with the thinly spread fiber bundle as in the technique described in Patent Document 1, the absolute amount of fibers is insufficient, and sufficient reinforcing strength cannot be ensured.

In addition, in Patent Document 2, which discloses a technique of using a thick fiber layer, a bending reinforcing member formed in a rod shape or plate shape is made of a fiber reinforced resin obtained by solidifying high-strength fibers such as carbon fibers or high-rigidity fibers with a resin. , a method of sandwiching as part of laminated lumber has been proposed. Further, regarding a method of sandwiching a fiber reinforcing material between laminated lumbers, Patent Document 3 also describes a method of sandwiching a fiber sheet between uneven wooden portions.

JP-A-2007-245431 Japanese Utility Model Laid-Open No. 1-159018 Japanese Patent No. 5306008

With these techniques, the wood-based laminated lumber cannot be reused after being used as a building material, and the whole is disposed of as waste.

In recent years, various techniques have been developed and researched to reduce carbon dioxide in the atmosphere with respect to global warming, which has been viewed as a problem on a global scale. In the construction industry, the use of wood, which absorbs carbon dioxide, is being reviewed, and the use of wood in middle- and low-rise buildings is being promoted. If the low strength and low rigidity of wood can be improved by the above technology, the range of utilization of wood may be expanded.

However, if the entire building material is incinerated as waste, the carbon dioxide stored in the laminated wooden material will be discharged. It is desirable in modern society to reinforce the laminated wood part so that it can be reused, but such a form of reinforcement has not yet been put into practical use.

SUMMARY OF THE INVENTION An object of the present invention is to provide a composite material that improves the bending performance of wood laminated lumber with a fiber-reinforced resin member and that can reuse the base laminated lumber after it is used as a building material. That is.

The present invention is a composite material consisting of a base material part made of wood and a reinforcing part, wherein the reinforcing part is a base material part connecting member, a reinforcing part protecting member, and a member disposed between them and adhered to both of them. The composite material is composed of a fiber-reinforced resin member, and is characterized in that the base member connecting member and the reinforcing member protecting member are not substantially directly bonded.

ADVANTAGE OF THE INVENTION According to the present invention, there is provided a composite material that improves the bending performance of laminated wooden lumber with a fiber-reinforced resin member, and that can reuse the laminated lumber as a base material after it is used as a building material. be able to.

It is a schematic diagram of the reinforcement part in this invention. 1 is a schematic diagram of a composite material of the present invention; FIG.

<Base material part>
In the present invention, laminated wood is used as the base material. The base material preferably has a cross section with dimensions of 100 to 300 mm wide and 100 to 1000 mm high, more preferably 105 to 180 mm wide and 105 to 450 mm high, particularly preferably 120 to 150 mm wide and 120 to 450 mm high. It is a laminated lumber. Laminated timber with this cross-sectional dimension is particularly expected to have a reinforcing effect against the lack of bending rigidity that occurs when the beams receive a large load or when the column spacing is widened in low-rise and medium-rise wooden buildings. cross-sectional dimension.

The performance of the beams required to prevent the beams from being excessively thick in low-rise and medium-rise buildings varies depending on the building design. Since pine-based wood is used, it is desirable that the bending strength and bending elastic modulus are equal to or higher than this. From this point of view, the composite material of the present invention preferably has a flexural strength of 20-140 MPa and a flexural modulus of 5-40 GPa.

The bending strength is more preferably 35-140 MPa, particularly preferably 60-110 MPa. With this range of bending strength, it can be used without increasing the beam cross-section even when the beam receives a large load or when the column spacing is widened in low-rise and large-scale buildings. preferable.

The bending elastic modulus is more preferably 10 to 40 GPa, particularly preferably 20 to 30 GPa. If the flexural modulus of elasticity exceeds 40 GPa, the flexural rigidity becomes too high, shear failure rather than bending failure is likely to occur, and shear reinforcement must be implemented, which is not preferable because the cost increases. If the flexural modulus is less than 5 GPa, the reinforcing effect is small, and in a low-rise building with a large space or a medium-rise building, when the beam receives a large load or when the column spacing is widened, the beam cross section becomes large, which is not preferable.

<Reinforcement part>
In the present invention, the base material part has excellent bending properties due to the presence of reinforcing parts on both sides thereof. The reinforcing part is composed of a base material part connecting member, a reinforcing part protecting member, and a fiber reinforced resin member disposed between them and adhered to them. In the reinforcing portion, the base material portion connecting member and the reinforcing portion protecting member are not substantially directly bonded. That is, the base material part joining member and the reinforcing part protecting member are connected by the fiber reinforced resin member, fixed to each other, and integrated (FIG. 2).
The fiber-reinforced resin member is adhered to both side surfaces of the base material through the base material connecting member to form a composite material (Fig. 2). Each member forming the reinforcing portion will be described below.

<Base member joining member and reinforcing member protecting member>
Both the base material joining member and the reinforcement protection member in the reinforcement preferably comprise at least two recesses, more preferably two recesses. These recesses are preferably cut separately, and are arranged at positions of preferably 5 to 45 mm inside from the end of the reinforcement protection member, preferably at intervals of 10 to 100 mm. A fiber-reinforced resin member is adhered and fixed to these concave portions.

If the two rows of recessed portions are arranged at the end of the reinforcing portion protection member other than the above positions, the fiber reinforced resin member will be exposed on the side surface of the reinforcing portion, and the dimensional adjustment of the reinforcing portion and the final composite You will not be able to use a wood grinder for finishing when used as a material. In this case, if the wood grinder is used forcibly, the fiber-reinforced resin member may damage the teeth of the wood grinder.

Since the fiber reinforced resin member does not exist in the portion between the end of the reinforcing portion protection member and the recess, the portion 5 to 45 mm from the end and the portion between the recesses 10 to 100 mm, the composite member of the present invention is not constructed. It is the part where screws and nails are used to fix materials such as plywood when used in . By arranging the recesses at a distance of 5 to 45 mm from the end of the reinforcing part protection member at intervals of 10 to 100 mm, it is possible to drive screws and nails without causing damage such as breakage or chipping during processing. can be widened, and other members can be easily fixed.

The recess is preferably a continuous recess having a width of 10 to 100 mm and is preferably cut parallel to the longitudinal direction of the base material.

<Fiber-reinforced resin member>
As the fiber-reinforced resin member, a fiber-reinforced resin member is used in which continuous fibers oriented parallel to the length direction of laminated wood used for the base material are solidified with a resin. A general-purpose reinforcing fiber having a strength suitable for reinforcing wood can be used as the continuous fiber. The reinforcing fibers are preferably inorganic fibers or organic fibers having a melting point or glass transition temperature of 200° C. or higher, more preferably 250° C. or higher.

Examples of continuous fibers of the fiber-reinforced resin member include carbon fibers, aromatic polyamide fibers (aramid fibers), polyarylate fibers, polyparaphenylenebenzobisoxazar fibers, polyphenylene sulfide fibers, polyimide fibers, and tetrafluoroethylene fibers. can be done. Since the composite material of the present invention is mainly used as a member for building a building, it is preferable that the strength of the fiber-reinforced resin member constituting the composite material does not easily decrease even in the event of a fire. From this point of view, carbon fiber, glass fiber or aromatic polyamide fiber is preferable, and carbon fiber or aromatic polyamide fiber is particularly preferable. These reinforcing fibers may be used alone or in combination of two or more.

When carbon fibers are used, acrylonitrile-based carbon fibers obtained by baking polyacrylonitrile-based fibers are preferable. When carbon fibers are used, it is preferable that the carbon fibers have a tensile strength of 2500 to 7000 MPa and an elastic modulus of 150 to 700 GPa. A sufficient reinforcing effect can be obtained with the tensile strength and elastic modulus within this range.

The continuous fibers constitute a fiber-reinforced resin member together with the resin. The form of the continuous fibers in the fiber-reinforced resin member can adopt various forms such as a UD base material in which the fibers are aligned in one direction, a combination of two or more directions, a woven fabric, and a non-woven fabric, depending on the required strength. can be designed Considering the balance between actual performance and cost, it is particularly preferable to use continuous fibers as a unidirectionally aligned UD substrate. As the UD base material, it is preferable to use a UD base material in which carbon fibers having high tensile strength and tensile modulus and high heat resistance are aligned in one direction.

The resin used for the fiber-reinforced resin member is a matrix resin, preferably a thermosetting resin. Examples of thermosetting resins include phenol resins, epoxy resins, and vinyl ester resins. Among them, phenol resin is preferable from the viewpoint of heat resistance.

The continuous fibers are preferably used so as to be oriented in the longitudinal direction of the laminated wood of the base material. By using it in this mode, it is possible to effectively exhibit the reinforcing effect of the fiber. The fiber-to-resin volume fraction in the fiber-reinforced resin member used in the present invention is preferably in the range of 40/60 to 60/40.

The physical properties of the fiber-reinforced resin member are preferably 900 to 2000 MPa in bending strength and 90 to 150 GPa in bending elastic modulus.

The main application of the composite material of the present invention is as a shaft material for building materials, and it is joined to other members such as columns and floors to form a building structure. For example, when used for beams, flooring materials such as plywood are fixed with screws and nails, so screwing and nailing should be done without damaging the fiber-reinforced resin members that are reinforcing materials as much as possible. There is a need to. Therefore, the fiber-reinforced resin member is thinner, but it is necessary to secure a sufficient amount of fibers necessary for reinforcement. The fiber-reinforced resin member for ensuring both the reinforcing performance and the space for screwing and nailing in use is, for example, a bar shape having a rectangular cross section with a width of 10 to 100 mm and a height of 2 to 60 mm, preferably It is preferably rod-shaped with a rectangular cross-section having a width of 20-50 mm and a height of 10-30 mm.

If the width and height of the fiber-reinforced resin member are not within these ranges, it will not only be difficult to obtain the reinforcing performance, or it will be difficult to provide a space for screwing or nailing. It becomes difficult to process the concave portions provided in the base material portion joining member and the reinforcing portion protecting member, and ultimately the reinforcement effect cannot be expected.

A rod-shaped fiber-reinforced resin member having such a rectangular cross section can be obtained by a general fiber-reinforced resin molding method, and in particular, it is preferably molded by a pultrusion method from the viewpoint of rod-shaped moldability.

<Adhesion of base material part joining member, reinforcement part protection member, and fiber reinforced resin member>
The reinforcing portion is configured using the base material portion joining member, the reinforcing portion protecting member, and the fiber reinforced resin member. A fiber reinforced resin member is adhered via an adhesive to at least two rows, preferably two rows of recessed portions respectively provided in the base member joining member and the reinforcing member protecting member. A fiber reinforced resin member is arranged between the base material part joining member and the reinforcing part protecting member. At this time, the base material part connecting member and the reinforcing part protecting member are not substantially directly bonded, and the base material part connecting member and the reinforcing part protecting member are integrated through bonding with the fiber reinforced resin member. It is important that It is particularly preferable that the base member connecting member and the reinforcing member protecting member are not directly bonded at all, and that there is a gap between them.

Note that not being substantially directly bonded means that the base material part bonding member and the reinforcement part protection member are allowed to be bonded with a relatively weak adhesive force, and the fiber reinforced resin member is not directly bonded. It means that the bonding is permitted with an adhesive strength of, for example, 10% or less, preferably 5% or less of the adhesive strength between the two.

The fiber-reinforced resin member according to the present invention is obtained by adhering a base-part joining member to the opposite side surfaces of the laminated material of the base-part, and based on the reinforcing effect of the fiber-reinforced member bonded to the base-part-joining member. Reinforcement effect is obtained by transmitting to the laminated wood of the material part.

Therefore, not only the adhesion between the base material part joining member and the base material part but also the adhesion between the base material part joining member and the fiber-reinforced resin member must be strong. All adhesions in the present invention can be performed using water-soluble polymer-isocyanate-based adhesives or resorcinol-based adhesives, which are adhesives for wood, as adhesives. Bonding is preferably performed by press bonding, and since wood materials are press bonded, the press pressure is preferably around 1.0 MPa, which is a level that does not break the wood material.

It is necessary to efficiently apply pressure to the bonding interface in bonding the base material portion bonding member and the fiber reinforced resin member. Therefore, it is necessary to set the total depth of at least two rows, preferably two recesses provided in the base material part joining member and the reinforcing part protection member to be less than the height of the fiber reinforced resin member. For example, if the height of the fiber-reinforced resin member is 30 mm, the depth of the recess provided in the base material part joining member and the reinforcement part protection member is 14.5 mm, and the total depth is 29.0 mm. By providing a gap of, for example, 1 mm or more between the base material part joining member and the reinforcing part protection member so that they do not come into direct contact with each other, i.e., do not directly adhere to each other, the press pressure is efficiently applied to the base material part joining member and the reinforcing part protection member. It can be applied to the bonding interface of the member.

On the other hand, when the gap between the two is narrow, for example, less than 1 mm, the base material part joining member and the reinforcing part protection member come into contact with each other, so that the press pressure is not sufficiently transmitted to the fiber reinforced resin member. The adhesion between the composite material and the reinforcing portion protection member becomes insufficient, and as a result, there is a high possibility that the performance of the composite material will not be fully exhibited.

<Roles of base material joining member and reinforcing member protecting member>
As described above, the reinforcing portion in the present invention has a form in which the fiber reinforced resin member is sandwiched between the base material portion joining member and the reinforcing portion protecting member. Here, the roles of the base material portion joining member and the reinforcing portion protecting member will be described.

The base material part joining member is a member that is adhered to the laminated material of the base material part and has a role of transmitting the reinforcing effect of the fiber reinforced resin member to the base material part. Adhesion between the base member and the base member is performed by press bonding using a water-soluble polymer-isocyanate adhesive or a resorcinol adhesive, which is an adhesive for wood, in the same way as ordinary laminated lumber. be able to.

On the other hand, the reinforcement protection member is the outermost layer of the composite material of the present invention. The role of the reinforcing part protection member is to protect the fiber-reinforced resin member arranged inside and to fix the floor material and interior material to the composite material when the composite material of the present invention is used as a building structural material. It plays a role as a space for nailing and screwing. Therefore, similarly to the base material part joining member, the adhesion between the reinforcing part protecting member and the fiber reinforced resin member must be strong, and it is important to employ the above-described method of manufacturing the reinforcing part.

<Reuse of base material>
The characteristics of the composite material of the present invention are that the fiber reinforced resin member not only improves the bending performance of the laminated wood material of the base material, but also allows the composite material integrated with the fiber reinforced resin member to be used as a building material. Second, the laminated material of the base material, which occupies most of the volume of the composite material, can be reused.

Normally, a reinforcing material is adhered to the inner or outer layer of the base material (laminated wood) to be reinforced, and floor materials such as plywood and interior materials such as ceiling materials are fixed to the base material itself by screwing or nailing. Therefore, there is no alternative but to dispose of all materials as waste after the building is demolished. However, in the composite material of the present invention, a fiber reinforced resin member is adhered to the laminated wood used as the base material via the base material part joining member, and a floor material such as plywood or the like is bonded via the reinforcement part protection member. Since interior materials such as ceiling materials are fixed by screwing or nailing, damage is limited to the reinforcement protection members when the building is dismantled. It can be reused by returning it to the laminated lumber that is the material part.

While it is used as a building material while being reinforced with fiber-reinforced resin members, the fiber-reinforced resin member mainly bears the mechanical weight, so physical deterioration of the laminated lumber itself of the base material does not occur. Possibility that it is less than normal laminated lumber is also conceivable.

（曲げ弾性係数の計算式）

The present invention will be further described in detail with reference to examples. Evaluation was performed by the following method.
(1) Adhesive strength The adhesive interface between the post-ganglionic member of the base material part and the wooden member of the reinforcing part protection member and the fiber reinforced resin member is 25 mm × 25 mm, and the adhesive interface is 60 mm so that the adhesive interface is the center (30 mm of wooden member + 30 mm of fiber member) was cut out as a test piece, the fiber-reinforced resin member was fixed to a jig, and pressure was applied to the wooden member so that shear stress was applied to the adhesion interface. The breaking load was measured and divided by the adhesion area to calculate the shear adhesion strength (MPa). It was judged to be bonded with a shear bond strength of 5.4 MPa or more.
(2) Bending physical properties For a specimen with a cross section of width 120 mm, height 390 mm, and total length of 8,000 mm, the distance between fulcrums is set to 7,020 mm (18 times the height of the section), and the specimen with a total length of 8,000 mm is divided into 2 points. A four-point bending test was performed in which a force was applied to the From the obtained maximum load and load-deflection curve, the bending strength and bending elastic modulus were calculated using the following formulas.
(Calculation formula for bending strength)

(Calculation formula for bending elastic modulus)

Example 1
(Base material and reinforcing effect)
As the base material, laminated cedar wood (E65-F225) having a cross section of 120 mm in width and 300 mm in height was used. The flexural properties of this laminated material are a flexural strength of 22.5 MPa and a flexural elastic modulus of 6.5 GPa.

(Base member joining member and reinforcing member protecting member)
As with the base material, the cedar material was also used for the base material joining member and the reinforcement protection member. A lumber lamina having a width of 125 mm, a height of 22 mm, and a length of 8,000 mm was prepared, and two rows of recesses having a width of 30 mm and a depth of 14.5 mm were cut at positions 17.5 mm from both ends in parallel with the lamina length direction. The interval between the two rows of recesses was 30 mm. Four sheets of this lamina were produced.

(fiber reinforced resin member)
For the fiber-reinforced resin member, continuous fiber of carbon fiber (manufactured by Toho Tenax Co., Ltd.) was used as the reinforcing fiber, and fiber-reinforced resin using vinyl ester resin as the matrix resin was used. This fiber-reinforced resin member was molded by pultrusion, and had a square cross section of 30 mm×30 mm and a length of 8000 mm. The obtained fiber-reinforced resin member had a bending strength of 1300 MPa and a bending elastic modulus of 110 GPa.

(Adhesion of base material part joining member, reinforcement part protection member, and fiber reinforced resin member)
A water-soluble polymer-isocyanate adhesive was applied to the two rows of recesses provided in the lamina of the obtained base material part joining member and reinforcing part protection member so as to be 300 g / m ² to form a fiber reinforced resin member. was inserted into each recess, the fiber-reinforced resin member was sandwiched between the base-material-protecting member and the reinforcing-portion-protecting member, and press-bonded at a press pressure of 0.8 MPa for 45 minutes to form a reinforcing portion. In the obtained reinforcing part, a gap of 1 mm is generated between the base material part joining member and the reinforcing part protecting member. It was integrated only by bonding with the protective member. When the shear bond strength between the fiber reinforced resin member and the base material part bonding member and the shear bond strength between the fiber reinforced resin member and the reinforcing part protection member were measured, both were 7.8 MPa, indicating that they were sufficiently bonded. I was able to confirm that. The dimensions of the reinforcement were 125 mm wide×45 mm high×8000 mm long.

(composite material)
A water-soluble polymer-isocyanate-based adhesive was applied to each of the obtained two reinforcement parts to join the base material so that the amount was 250 g/m ² , and laminated lumber (E65-F225) was used as the base material part. They were placed in contact with opposite side surfaces and press-bonded. The press pressure was 0.8 MPa, and the press time was 45 minutes. After pressing, 6 peripheral surfaces of the obtained composite material were cut to adjust the dimensions to 120 mm in width×390 mm in height×8000 mm in length.

A four-point bending test was performed on the obtained composite material, and the bending strength was 102.1 MPa and the bending elastic modulus was 25.8 GPa.

Comparative example 1
In Example 1, a reinforcing portion was produced in the same manner as in Example 1, except that the depth of the concave portion provided in the base material portion joining member and the reinforcing portion protecting member was 15.5 mm, and a composite material was produced in the same manner. did. As a result, when the shear bond strength between the fiber reinforced resin member and the substrate part joining member and the shear bond strength between the fiber reinforced resin member and the reinforcement part protection member in the reinforcement part were measured, they were each 0.6 MPa. Confirmed lack of adhesion. Further, when the obtained composite material was subjected to a four-point bending test, the bending strength was 29.3 MPa and the bending elastic modulus was 8.4 GPa.

The composite material of the present invention can be used, for example, as building materials such as columns and beams. When the building is demolished after being used, the base material can be returned to laminated lumber, so that it can be used again as ordinary laminated lumber. Moreover, it can be used as a composite material by bonding a new reinforcing portion.

REFERENCE SIGNS LIST 11 Fiber reinforced resin member 12 Base material part joining member 13 Reinforcement part protection member 21 Reinforcement part 22 Laminated wood that is the base material part

Claims (10)

A composite material consisting of a base material part made of wood and a reinforcement part, wherein the reinforcement part comprises a base material part joining member, a reinforcement part protection member, and a fiber-reinforced resin member disposed between and adhered to both. A composite material characterized in that the base member connecting member and the reinforcing member protecting member are not directly bonded at all, and a gap exists between them . The composite material according to claim 1, having a flexural strength of 20-140 MPa and a flexural modulus of 5-40 GPa. 2. The composite material of claim 1, wherein the substrate portion has cross-sectional dimensions of 100-300 mm in width and 100-1000 mm in height. In the reinforcing part, the base material part joining member and the reinforcing part protecting member each have at least two recesses cut therein, and the recesses are located 5 to 45 mm from the end of the reinforcing part protecting member in the width direction. 2. The composite material according to claim 1, wherein the recesses are arranged at intervals of up to 100 mm, and the fiber-reinforced resin members are adhered and fixed in the recesses. 5. The composite material according to claim 4, wherein the recess is a continuous recess with a width of 10-100 mm and is cut parallel to the longitudinal direction of the base material. The fiber-reinforced resin member is rod-shaped and has a rectangular cross section with a width of 10 to 100 mm and a height of 2 to 60 mm. 5. The composite material of claim 4, which is oriented. 2. The composite material according to claim 1, wherein the continuous fibers of the fiber-reinforced resin member are carbon fibers, glass fibers or aromatic polyamide fibers. A composite material according to claim 1, which is a building material. A method of recovering a substrate portion from the composite material of claim 1, wherein the substrate portion is recovered by cutting the reinforcement portion from the substrate portion. The composite material according to claim 1, wherein the substrate portion is a substrate portion recovered by the method according to claim 9.

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