JPH0825172B2 - Cylindrical veneer laminated material - Google Patents

Description

Detailed Description of the Invention

[0001] The present invention relates to a cylindrical veneer laminated material suitable for use as a structural member made of so-called veneer laminated material (Laminated Veneer Lumber, abbreviated as LVL hereafter) manufactured by laminating thin wooden plates.

[0002]

2. Description of the Related Art It is said that forests are currently disappearing on a global scale, and in connection with the progress of desertification, environmental destruction has been recognized as a serious problem. For that reason, it has long been called for effective use of timber resources, but it is also a fact that a definitive solution has not yet been obtained.

Under such circumstances, the LVL, which has recently been put into practical use, is an excellent material that contributes to the effective utilization of wood resources. This is because the LVL is a product in which a thin wig is peeled off with a lace or the like to make a thin wooden plate (single plate), and the thin plates are laminated in the same fiber direction to form a plate shape, which is inferior in quality. Combined with the development of a thin stripping lace capable of stripping thinned wood, etc., the above thinned wood can be used as a raw material and can be easily subjected to chemical treatment. This is because it is possible to provide stability, improve moisture absorption and water absorption, and improve durability.

[0004]

LVL is generally a smooth and thick plate-like material, and its application is used not only for construction materials but also for specially processed materials as furniture, fittings, etc. However, when it is used as a large cross-section structural material for construction, the number of laminated layers is very large, which is uneconomical. In addition, sufficient research has not been conducted on its durability when used on outdoor standing structures such as utility poles and various poles. Not not.

However, while the demand for large cross-section structural materials and cylinders has increased recently, large-diameter wood resources have decreased, making it difficult to supply them with raw materials and laminated wood.
There is a need to develop techniques for producing such materials using low quality virgin raw materials.

The present invention has been made based on the background described above, and it is possible to use resources that do not lead to deforestation, such as thinned wood, as a raw material, and it is lightweight yet strong and can be processed. It is an object of the present invention to provide a cylindrical veneer laminated material which is easy to use and has a characteristic that the grain is exposed and is beautiful, and yet can be used as a structural material.

[0007]

A cylindrical veneer laminated material according to claim 1 of the present invention is formed by laminating a plurality of wood thin plates on each other with an adhesive in a state where the grain directions are substantially aligned. The formed laminated plate is press-molded so as to form an arc in a direction substantially perpendicular to the grain direction to form a unit cylindrical laminated plate, and both sides of the unit arc-shaped laminated plate in the longitudinal direction and the circumferential direction of the arc. A finger joint portion is provided in the portion, and the finger joint portions of a plurality of unit arc-shaped laminated plates are fitted and adhered in the longitudinal direction and the circumferential direction, and the unit arc-shaped laminated plates are joined in the circumferential direction. Is performed in a state where the joint portion extending in the circumferential direction is vertically displaced.

[0008]

According to a second aspect of the present invention, there is provided a cylindrical veneer laminated material according to the first aspect, wherein the wood thin plate is impregnated with a synthetic resin. It is a thing.

According to a third aspect of the present invention, there is provided a cylindrical veneer laminated material according to the first or second aspect, wherein the cylindrical veneer laminated material has a hollow hollow synthetic resin foam. It is characterized by being filled.

[0011]

According to the cylindrical single plate laminated material of the above-mentioned claim 1, since the unit arc-shaped laminated plates are formed by laminating in a state where the grain directions are aligned with each other, the unit circular arc laminated plates can be formed in a direction perpendicular to the grain direction. The state in which the arc is formed can be easily maintained. The unit arc-shaped laminated plate is formed by pressing the laminated plate so as to form an arc, and thus has high strength.

Further, finger joint portions are provided on both sides of the unit circular arc laminated plate in the vertical direction and the circumferential direction of the circular arc, and a plurality of finger joint portions are fitted in and bonded to the finger joint portions in the vertical direction. Further, since the cylindrical single plate laminated material is joined by being bonded in the circumferential direction, the obtained cylindrical single plate laminated material has a substantially solid integral structure.

In addition, since the unit circular arc laminated plates are joined in a state of being displaced in the longitudinal direction in the circumferential joining, the joined portions of the obtained cylindrical single plate laminated materials are dispersed, It is possible to avoid concentration of non-uniform strength in the longitudinal direction, and to improve strength of the cylindrical single-plate laminated material by avoiding concentration of stress.

According to the cylindrical veneer laminated material of the second aspect, since the wood thin plate is impregnated with a synthetic resin and the surface layer is compacted, the durability and strength of the wood thin plate itself are increased. Therefore, the durability and strength of the finally obtained cylindrical single plate laminated material are increased, and the bending strength is greatly increased.

According to the cylindrical veneer laminated material of the third aspect, since the hollow portion of the cylindrical veneer laminated material is filled with the synthetic resin foam, the lateral side of the cylindrical veneer laminated material. The compressive strength in the direction increases.

FIG. 1 is a partially cutaway perspective view of a cylindrical single plate laminated material of the present invention. As shown in this figure, the cylindrical single-plate laminated material 1 of the present invention is formed by assembling a joint-portion-formed laminated plate 2 having a circular arc-shaped cross section into a cylindrical shape. The joint portion-forming laminated plate 2 is composed of a laminated plate 4 in which a plurality of thin wooden plates 5 are laminated on each other with an adhesive in a state where the grain directions are aligned. This laminated board 4
Is press-formed so as to form an arc in a direction perpendicular to the grain direction, and first, a unit arc-shaped laminated plate 3 shown by a two-dot chain line in FIG. 1 is formed. Finger joint parts 21 are provided on both sides to form a joint part forming laminated plate 2, and a plurality of these are joined vertically and horizontally to form a cylindrical single plate laminated material 1.

As the thin wood plate 5, a thin wood material made of thinned wood is thinned to a thickness of several mm by a known method. When thinning, the grain is set so as to extend in the longitudinal direction, and a predetermined number of sheets are stacked to form a laminated plate 4, as shown in FIG. Therefore, the laminated plates 4 that are laminated have the same grain extending direction, and are difficult to bend in the longitudinal direction, but are in a state where arcs are easily formed by pressing in the width direction.

When laminating the above, each wood thin plate 5 is previously prepared.
Adhesive is applied between them. Then, as shown by the alternate long and short dash line in FIG. 2, static pressing is performed by a pressing jig P including an upper mold having a convex portion formed in the width direction and a lower mold having a concave portion facing the upper mold. Thus, the laminated plate 4 and the unit arc-shaped laminated plate 3 are formed all at once. It is to be noted that, without performing the static pressure molding as described above, first, the laminated plate 4 in which the adhesive is uncured is formed, and then a pair of convex portions and concave portions corresponding thereto are formed on the laminated plate 4. A dynamic method in which the unit circular arc laminated plate 3 is formed in two steps by passing between rollers and by high frequency heating or the like can also be adopted.

Any adhesive can be used as the adhesive to be applied between the thin wood plates 5, but as the thermosetting adhesive, thermosetting resorcinol-based, phenol-based, melamine-based, urea-based or An adhesive made of a urea melamine copolymer-based resin and an adhesive made of a resorcinol-based or isocyanate-based resin are particularly suitable as the room-temperature-curable adhesive.

Before laminating and press-molding as described above,
It is effective to improve the durability of the product if the wood thin plate 5 is impregnated with various synthetic resin monomers or oligomers in advance. This impregnation is usually carried out by immersing the thin wooden plate 5 in the solution of the above resin for a predetermined time, but it may be forcedly impregnated by pressure injection. Examples of such synthetic resins include initial condensates of water-soluble phenolic resins or melamine resins, monomers or oligomers of vinyl resins such as methyl methacrylate and styrene, low molecular weight unsaturated polyester resins, low molecular weight alkyd resins or isocyanates. Are preferably used.

The unit arc-shaped laminated plate 3 formed as described above is provided with finger joint portions 21 on both sides in the vertical and horizontal directions to form the joint-portion-formed laminated plate 2. Vertical finger joint 2
1 is a finger joint portion 21 in the horizontal direction, which is obtained by pressing the longitudinal end portion of the unit circular arc laminated plate 3 against the cutter rotating at a high speed and moving the same in parallel.
Can be formed by pressing the lateral end portion of the unit circular arc laminated plate 3 against the cutter and moving it in parallel.

The finger joint is a known method for increasing the area of the two joints when joining two rigid bodies to obtain a stronger joint. Usually, the joint surface is A corrugated shape, a concavo-convex shape, a sawtooth shape, etc. are adopted, but in the present invention, as shown in FIG. 1, a sawtooth shape is adopted in both vertical and horizontal directions. However, the cylindrical single plate laminated material of the present invention is not limited to the tooth profile of the saw.

Further, since the arc shape of the joint part forming laminated plate 2 is a circular arc of 1/6 circle (that is, the central angle of the arc is 60 °), the joint part forming laminated plate 2 is circumferentially formed. As they are joined together, a cylinder is formed by using the six joint part forming laminated plates 2.

When the cylinders are assembled, the joint portions formed by the arcs of the joint portion-forming laminated plate 2 by the finger joint portions 21 on both sides are displaced from the adjacent joint portions, that is, the joint portions. It is preferable to join the formed laminated plates in a state of being vertically displaced (staggered).

The joint portion forming laminated plate 2 is joined by applying an adhesive to the finger joint portion 21. As the adhesive used in this case, an adhesive of resorcinol resin or isocyanate resin is preferably used. In order to make a strong joint, after forming a cylindrical shape on the joint part-forming laminated plate 2 using the adhesive as described above, the surface of the cylinder is fastened by tightening a tab-shaped metal fitting, and It is preferable to charge the drying furnace in this state and heat-treat for a predetermined time.

In the cylindrical veneer laminate 1 of the present invention obtained as described above, the joint part-forming laminates 2 obtained by laminating the thin wood plates 5 are firmly bonded to each other vertically and horizontally by the finger joints. Because they are combined and formed,
It can be sufficiently used as a structural material such as a pillar.

If the joint portion forming laminated plates 2 are joined in a zigzag manner in a state of being vertically displaced, the joint portions are dispersed and the concentration of stress on these portions can be avoided, so that a cylinder of higher strength can be avoided. The single veneer laminated material 1 can be obtained.

Further, if the thin wood plate 5 is impregnated with a synthetic resin in advance, the thin wood plate 5 itself has a large strength, so that the obtained cylindrical veneer laminate 1 has a very large strength. become.

In addition, if the hollow portion of the cylindrical veneer laminate 1 is filled with the synthetic resin foam 6, the compressive strength and bending strength in the diametrical direction of the cylindrical veneer laminate 1 are increased. Is a more suitable material.

Example 1 A wood thin plate (single plate) having a thickness of 2.5 mm was manufactured by a known method using a raw wood made of a thinned wood of cedar as a raw material. Then, this wood thin plate was first dipped in a 20% solution of a water-soluble low molecular weight phenolic resin PR-A to sufficiently impregnate the wood thin plate.

Then, a phenol resin adhesive PL-109 was applied to one surface of the 18 wood thin plates impregnated with the above resin.
A 1/6 arc concave mold with a length of 1 m and a radius of 150 mm and a 1/6 arc convex mold with a length of 1 m and a radius of 115 mm are applied and laminated at a rate of 150 g / m ² per adhesive layer. It was sandwiched between the two and pressed to form a unit arc-shaped laminated plate. The molding conditions at this time were a temperature of 140 ° C., a pressing force of 10 kgf / cm ² , and a heating time of 30 minutes.

Thus obtained length 1 m, thickness 35 m
Finger joints were formed on both side portions in the longitudinal direction and the circumferential direction of a unit circular arc laminated plate having m, an inner circular arc length of 120 mm and an outer circular arc length of 157 mm to obtain a joint part forming laminated plate. The finger joint has a saw-tooth shape, the pitch of the ridges of the saw is 3.5 mm, and the depth of the valley is 9 mm.

Six pieces of the above-mentioned joint portion-forming laminated plates were prepared, and the resorcinol resin adhesive was applied to the finger joint portions on both sides in the circumferential direction thereof to form a cylindrical shape, which was then tightened with a band using a winch. It was fixed and allowed to stand at room temperature for 20 hours to obtain a cylindrical veneer laminated material.

Four cylindrical veneer laminates were prepared, and the hollow portions of these three bodies were filled with three kinds of hard urethane resin for synthetic wood having the compositions shown in Table 1. The remaining one is not filled with the urethane resin.

[0035]

[Table 1]

The four cylindrical single-plate laminated materials shown in Table 1 were sliced into slices having a thickness of about 23 cm to obtain samples for strength test. Sample No. The thickness of the sample 1 not filled with urethane foam is 30 cm.

Table 2 below shows the dimensions of such samples, the specific gravity of the filled urethane resin, and the specific gravity of the composite (including the cylindrical single-plate laminated material).

[0038]

[Table 2]

A strength test was carried out by placing the sliced sample on a sample stand of a strength tester so that the circumferential surfaces were up and down, and applying pressure from above and below until the sample broke.
In addition, when observing the situation at the time of breakage, the parts other than the finger joint part were broken, and the finger joint part was completely intact. This shows that the joining by the finger joint is excellent.

The test results will be described below with reference to the drawings.

FIG. 3 is a graph showing the relationship between the load applied to the sample in the above strength test and the compressive deformation.

As can be seen from this graph, as the specific gravity of the urethane resin increases, the compressive deformation decreases, and the maximum load (the load when the sample breaks) increases proportionally.

This can be confirmed more clearly by the graph of FIG. 4 in which only the relationship between the specific gravity of the urethane resin and the maximum load is extracted. For example, the one whose specific gravity is 0.4 is more than the one not filled with urethane resin,
It shows about 30 times the strength. This eloquently tells how the resin filling contributes to the increase in strength.

FIG. 5 shows the relationship between the amount of deformation in the compression and tension directions at the maximum load and its Poisson's ratio and the specific gravity of the urethane resin. As can be seen from FIGS. 3 and 4, the maximum load increases as the specific gravity of the resin increases, so the maximum deformation at the time of breakage increases, but the maximum in the tensile direction becomes smaller because it is constrained by the filled urethane resin. Therefore, the Poisson's ratio tends to decrease linearly as the specific gravity of the resin increases.

As described above, the fact that the resin is less deformed against a lateral load (load in the tensile direction) indicates an increase in refraction strength when used as a column, which means that This means that a cylindrical single plate laminated material filled with a resin as a structural material is excellent.

Example 2 A joint portion-forming laminated plate was manufactured under the same conditions as those of Example 1 except for the dimensions and other manufacturing conditions. However, at this stage, finger joint portions are not provided on both side portions in the width direction of the joint portion forming laminated plate.

Then, the resorcinol resin adhesive is applied to the finger joint portions on both sides in the longitudinal direction of the joint portion-forming laminated plate to join six sheets in the longitudinal direction, and a pressure of about 60 kg / cm ² is used by using a hydraulic jack. After pressing for 5 seconds at room temperature, the mixture was left at room temperature for about 1 week, and then finger joints were formed on both sides in the width direction to produce a long (6 m) joint-forming laminate.

Six sheets of this long joint portion forming laminated plate were prepared, and this time, the same adhesive as above was applied to the finger joint portions in the circumferential direction of the arc to join the six sheets.
Since the plates were alternately displaced in the longitudinal direction during joining, the unit-joint-forming laminated plates are arranged in a zigzag pattern. Since they are displaced as described above, the both sides in the longitudinal direction are in a state of missing teeth and do not form a cylinder. As a result of cutting that portion, the length of the cylindrical veneer laminate is 5.4 m. Became.

A load of 2 tons was applied to the central portion with both ends of this cylindrical material supported by a span of 5 m, but the bending deformation of the central portion was only 16 mm.

These facts show that the column made of the cylindrical single plate laminated material can be used as a structural material, and if the hollow portion is filled with a resin foam, it can be used for an extremely high-performance structural material. Become a pillar.

[0051]

As described above, according to the present invention, the thin wood plates are laminated on each other with the adhesive in the state that the grain directions are matched to each other to form a unit arc-shaped laminate, and the unit arc-shaped laminates are joined vertically and horizontally. Since it is used to form a cylindrical veneer laminated material, it is possible to use inexpensive raw materials that do not lead to deforestation, such as thinned wood that could not be used as a conventional structural material. Is characterized by.

Further, since the unit arcuate laminated plate in which the thin wooden plates are laminated is provided with finger joints in the vertical and horizontal directions and is joined to each other by the finger joints, the obtained cylindrical single plate laminated plate is obtained. The material has high strength and can be sufficiently used as a structural material such as a pillar.

In addition, since it is made of wood, it is relatively lightweight,
Its application range is wide because it is easy to process and handle.

[Brief description of drawings]

FIG. 1 is a partially cutaway perspective view of a cylindrical single plate laminated material of the present invention.

FIG. 2 is a perspective view showing a configuration of a laminated plate.

FIG. 3 is a graph showing the relationship between the load and the deformation amount in the results of the load test on the sample of the cylindrical single plate laminated material.

FIG. 4 is a graph showing the relationship between the breaking load and the specific gravity of the filling resin in the results of the load test on the sample of the cylindrical single plate laminated material.

FIG. 5 is a graph showing the relationship between the deformation amount and the specific gravity of the filling resin under the breaking load, and the Poisson's ratio and the specific gravity of the filling resin under the breaking load among the results of the load test on the sample of the cylindrical single plate laminated material. It is a graph which shows a relationship.

[Explanation of symbols]

 1 Cylindrical veneer laminated material 2 Joint part forming laminated plate 21 Finger joint part 3 Unit circular arc laminated plate 4 Laminated plate 5 Wood thin plate

Claims (3)

[Claims] 1. A laminated plate formed by laminating a plurality of thin wood plates on each other with an adhesive in a state where the grain directions are substantially coincident with each other to form an arc in a direction substantially perpendicular to the grain direction. A unit cylindrical laminated plate is formed by pressing, and finger joint portions are provided on both sides of the unit circular arc laminated plate in the longitudinal direction and the circumferential direction of the circular arc. Ri Na finger joint is fitted bonded in the longitudinal direction and the circumferential direction, the unit arc
The circumferential joining of the circular laminated plates is performed by a joy that extends in the circumferential direction.
Cylindrical laminated veneer characterized that you have done in a state in which shifted the cement portion in the longitudinal direction. 2. The thin wood plate is impregnated with a synthetic resin.
Cylindrical laminated veneer according to claim 1, wherein Nodea Rukoto. 3. The cylindrical veneer laminated material is synthesized in a hollow portion.
The cylindrical single plate laminated material according to claim 1 or 2, which is filled with a resin foam .