JPH0548723B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a bonded veneer veneer formed by bonding a plurality of veneer veneers.

Conventionally, bonded veneer veneers have been used to form plywood or laminated veneer materials (L, V, L), etc., but for example, by interposing an adhesive at the joining edge of the veneer veneers to be bonded. The resulting bonded veneer veneer generally has poor straightness at the bonded edge;
Alternatively, the bonding strength may not be sufficient for handling due to the fact that the vicinity of the bonding edge is prone to chipping, and furthermore, the bonding area is limited due to the thickness.
Handling in so-called post-processes, such as when stacking other veneer veneers and forming them into plywood, etc. is poor, and in order to solve this problem, increasing the amount of adhesive used makes it difficult to bond. If the cost tends to increase, or if the joint edge is formed diagonally (so-called scarf joint) to increase the bonding area, the yield of veneer veneer will decrease, so in any case, bonded veneer veneer The disadvantage was that the cost was inevitably high.

Other methods include, for example, bonded veneer veneers bonded to paper with bonding tape coated with adhesive or rewet adhesive, or bonded threads made of wire impregnated and coated with thermoplastic adhesive. There are bonded veneer veneers, etc. that are bonded together, but none of them can be said to have sufficient bonding strength, and in the case of the former in particular, the paper of the bonding tape may peel between the layers, even if localized. There are defects that reduce strength, or when plywood etc. is cut at a location that includes the joint tape, foreign paper is exposed on the cut surface and stands out, which may reduce the quality of the plywood etc. In addition, the thermoplastic adhesive tends to ooze out to the surface due to hot pressure during molding into plywood, etc., and there is a high possibility that the quality of the plywood etc. will deteriorate.

The present invention provides a bonded veneer veneer with a new configuration that eliminates the various drawbacks of the conventional bonded veneer veneers, and thereby aims to streamline the process of forming plywood, etc. .

Hereinafter, the present invention will be described in more detail with reference to an example of implementation illustrated in the drawings.

As is clear from FIG. 1 or 2, the bonded veneer veneers according to the present invention are oriented in the fiber direction in the direction across the bonding edges 2 or 5 of the veneer veneers 1a, 1b or 4a, 4b to be bonded. A small piece 3 or 6 of a thin veneer veneer is pasted with an adhesive (not shown) across the joining edge 2 or 5, and is formed as a joined veneer veneer 1 or 4. It is.

For bonded veneer veneers with such a configuration, there is a risk that the straightness of the bonded edges will have a serious negative effect on the bonding strength.
There is no risk of chipping near the joint edge, and as is well known, the strength of veneer veneer in the fiber direction is greater than that of paper, etc. even if it is thin. Since it is possible to arbitrarily set the adhesive area, rigidity, etc., it is possible to provide the bonding strength necessary for handling, and the handling in the post-process is significantly better than before. In addition, since only a relatively small amount of adhesive is required and there is no need to cut out any excess joining edges, the total cost is relatively low. There is little risk that the adhesive will ooze out to the surface and deteriorate the quality of the plywood, etc., and furthermore, as illustrated in FIG. . Even if the thin veneer veneer is cut, the small pieces of the thin veneer veneer are made of the same material as the bonded veneer veneer, so they can hardly be identified.
Even if it could be identified microscopically, it would not feel strange at all,
Since there is no risk of deteriorating the quality of plywood, etc., it is generally significantly more effective than conventional bonded veneer veneers, and the effect of implementing the present invention on streamlining the process of forming plywood, etc., is extremely large.

In addition to the state in which the small piece of thin veneer veneer is attached, as illustrated in FIG. If necessary, as illustrated in FIG. 6, for example, a small piece 6 of thin veneer veneer is pasted by pressure clamping using a pair of clamping members 15 and 16 that can be separated from each other, and the bonded veneer is bonded. To the surface of the veneer 4,
One example is a state in which at least a portion (all in the embodiment) of the small piece 6 of the thin veneer veneer is collapsed, but in the former case (Fig. 5), it is also difficult to compress the thin veneer during the process of forming it into plywood, etc. As a result, the bonded veneer veneer or another veneer veneer was crushed, so there was no particular problem in practical use, regardless of the adhesion state.

In addition to the general usage example of forming plywood etc. using bonded veneer veneers so that the small pieces of thin veneer veneers are located inside the plywood etc. as in the example,
For example, plywood or the like is formed using bonded veneer veneers so that the small pieces of the thin veneer are positioned on the surface side of the plywood, etc., and if necessary, the thin veneer veneer is removed by sanding or other removal means. An example of using a bonded veneer veneer to remove a small piece of a board is given, or as mentioned above, a small piece of a thin veneer veneer is the same material as a bonded veneer veneer, so it is obvious from the surface side. Taking advantage of the fact that it does not feel strange, one example of its use is to leave small pieces of thin veneer on the surface of plywood, etc., to change the design of the joint.

In addition, the planar shape of the small piece of the thin veneer veneer may be rectangular or tortoise-shell shaped as exemplified in the above embodiments, or may be square, diamond-shaped, circular, or elliptical, although not shown. From the viewpoint of ease of creation and prevention of damage, simple shapes are preferred, but from the above-mentioned design point of view, for example, heart-shaped, butterfly-shaped, cloud-shaped, etc. Thus, even if it is somewhat complicated, it is unavoidable or from the point of view of increasing the bonding strength, a long strip in the direction orthogonal to the fibers is effective.

The dimensions of the small pieces of the thin veneer veneer, the number of pieces pasted, the material strength, etc. are closely related to the bonding strength,
These are the factors that determine the characteristics of a bonded veneer veneer, but since they are interrelated, it is difficult to determine specific values for each one, and the desired bonding strength can be determined by comparing and considering the mutual relationships. Therefore, it is most desirable to select the bonding strength as appropriate, but reference values based on experiments are listed below as a rough guide to values that satisfy the bonding strength required for normal handling.

First of all, regarding the thickness of the small piece of thin veneer, it can be quite thin compared to the thickness of the veneer veneer to be joined, and in experiments, it has been found that the thickness is about half the thickness of the veneer veneer to be joined. We carried out step-by-step experiments as appropriate up to a thickness of about 0.2 mm, which can be easily obtained by normal abrasion, and found that no particular problems were found in normal handling, including the straightness of the fibers. In terms of the stability of the material strength and the ease with which it can be dented as described above, it is recommended that the thickness be approximately 1/4 to 1/10 of the thickness of the veneer veneers to be joined. If it is appropriate and the thickness is relatively thick, chamfering the end surfaces (side surfaces and end surfaces) of the small pieces of the thin veneer veneer on one or both sides will make it easier to join the veneer veneers to be joined.・Because there is no difference in level at the boundary with other veneer veneers, etc., the adhesive strength and aesthetics are good.

Next, the width in the direction perpendicular to the fibers of small pieces of thin veneer veneer was tested in stages starting from 2 mm, and although no particular problems were observed in normal handling, there were some tests including prevention of breakage. In terms of ease of adhesion, it is approximately 10 to 50 mm, and if the main goal is to make its existence as unknown as possible, a value of 10 mm or less (preferably around 4 mm) is a good standard. However, if you desire a reinforcing strength greater than the bonding strength required for normal handling, use a material that is long in the direction perpendicular to the fibers and has a width that can cover all the joining edges of the veneer veneers to be joined. The concept of a small piece in the present invention also includes the so-called band-shaped pieces as described above.

Next, the length in the same direction as the fibers of a small piece of thin veneer veneer is not closely related to bonding strength, so it can be 4 to 10 times the thickness of the veneer veneer to be bonded, or 10 to 30 mm. This length is appropriate because it makes it easy to adhere, but even if it is longer than that, there is no practical difference.

Next, as for the number of small pieces of thin veneer veneer to be pasted, it depends on the width of each small piece and the orthogonal direction, but there is no particular restriction from one or more pieces. There is no problem even if a large number of sheets are attached to the veneer, but it is preferable that each sheet be attached at least near both ends of the joining edge, and at least 100 times (preferably 50 times or less) the thickness of the veneer veneer to be joined. ), the handling is even better. Of course, as illustrated in FIG. 7, for example, the veneer veneer 1 to be joined
If the bonded veneer veneer 17 is configured with small pieces 18 of thin veneer veneer affixed to both the front and back surfaces of 7a and 17b, the bonding strength will be even stronger and the handling will be improved. It is extremely good.

Furthermore, the material strength of a small piece of thin veneer veneer is closely related to the straightness of the fibers in the thickness direction of the small piece, so it is preferable that the small piece has fibers that are straight in the thickness direction. It is not necessary to match the wood species to the veneer veneer to be used; for example, there is no problem in using a small piece of thin veneer veneer made of softwood, which has stronger fibers, to join veneer veneer made of South Sea hardwood.

On the other hand, the adhesive used to attach thin veneer veneers may be the same adhesive (usually a thermosetting adhesive) used when forming bonded veneer veneers into plywood, or the same adhesive. Adhesives of similar properties are suitable, but are not necessarily limited to them; for example, even if a thermoplastic adhesive is used, it is possible to use a bonded veneer veneer in the condition shown in Figure 3. Since the thermoplastic adhesive can be prevented from seeping out onto the surface, it can be applied to a variety of known adhesives, including adhesive adhesives, rewetting adhesives, moisture-curing adhesives, etc. It may be used selectively as appropriate, and if necessary, multiple types of these adhesives may be used in a superimposed manner.

In addition, as a specific form of pasting small pieces of thin veneer veneer, in addition to the general form in which small pieces of thin veneer veneer formed into a predetermined shape are individually pasted one after another, for example, a rectangular shape may be used. Regarding the shape, square shape, etc., a long strip in the fiber direction is sequentially cut and pasted according to the desired shape, or small pieces of thin veneer veneer are pre-formed into a predetermined shape. For example, a continuous band-shaped adhesive tape is attached to the adhesive tape, wound into a drum shape, and pasted one after another while being rolled out in a manner similar to so-called label pasting.In any case, for example, thermoplastic adhesive When using an adhesive such as a tacky adhesive that can be adhered at all times, it is also effective to apply the adhesive in advance.

Of course, the fiber directions of the veneer veneers to be joined do not necessarily have to be aligned in the same direction, and the state of adhesion of the thin veneer veneer and the thickness of the thin veneer veneer in the embodiment shown in Also, the planar shape of the thin veneer veneer, the properties of the adhesive, etc. do not necessarily have to be the same on both sides.

Furthermore, the bonded veneer veneer according to the present invention does not preclude the use of conventional bonding means in combination; for example, as in the embodiment shown in FIG. 2, the fiber direction of the veneer veneer to be bonded is perpendicular to the bonding edge. In the case of so-called longitudinal joints, it is possible to provide reinforcement strength that exceeds the joint strength required for normal handling by using a joining method in which adhesive is interposed at the joining edge, and the reinforcement strength can be increased. It is effective because the bonded veneer veneer can be used for various applications, and it is also extremely effective to apply the bonding form of the bonded veneer veneer according to the present invention to the bonding form of plywood and the like.

[Brief explanation of the drawing]

The drawings are for explaining the present invention, and FIGS. 1 and 2 are plan explanatory diagrams of a bonded veneer veneer according to the present invention, and FIG. 3 is a plan view of a bonded veneer veneer according to the present invention. FIG. 4 is an enlarged partial side cross-sectional view of a laminated veneer material formed using bonded veneer veneers according to the present invention;
5 and 7 are enlarged side cross-sectional views of a bonded veneer veneer according to the present invention, and FIG. 6 is an enlarged side cross-sectional view of a bonded veneer veneer according to the present invention. It is a diagram. 1, 4, 17... Bonded veneer veneer according to the present invention,
1a, 1b, 4a, 4b, 17a, 17b...Plywood veneer to be joined, 2,5...Joining edge, 3,6,1
8...Small piece of thin plywood veneer, 7, 8, 10, 11,
12, 13...Other veneer veneer, 9...Plywood, 14...
Laminated veneer material, 15, 16... a pair of clamping members.

Claims (1)

[Claims] 1. A bonded veneer veneer consisting of a small piece of thin veneer veneer whose fiber direction is oriented in a direction that crosses the bonding edge of the veneer veneer to be bonded, and is pasted with an adhesive in a state that crosses the bonding edge.