JPH07115322B2 - Adhesion method for veneer veneer with back crack and other plate - Google Patents

Description

The present invention relates to a method for attaching a veneer veneer having a back crack to another plate material.

On the back surface of veneer veneer (hereinafter simply referred to as veneer) machined from veneer lace slicer, etc., local tear cracks along the fiber caused by bending during cutting,
It is well known that a large number of so-called back cracks are present at every interval related to the thickness of the veneer, and the back cracks have a shallow absolute depth as the veneer thickness decreases. Although it is possible to suppress the depth by properly setting various cutting conditions, it is essentially difficult to prevent, and as shown in FIG. Due to its presence, the veneer 1 usually bends in the orientation shown.

By the way, as illustrated in FIG. 9, the thus-curved veneer is appropriately dried or not dried with an adhesive, as illustrated in FIG.
When it is integrally attached to another suitable plate material, for example, the veneer 3 which is relatively thin and has no remarkable back cracking, it is inevitably flattened, but the inner surface of the back cracking is Since it is a surface formed by tearing, it is extremely rough, and since countless fine wood pieces are also sandwiched between them, it is difficult to restore it to a close contact by simply flattening it. The phenomenon that a considerable gap is generated is caused, and its existence becomes remarkable.

Also, as a peculiar example, when an extremely thick veneer is cut from a relatively thin log, veneer 1
May be curved on the contrary, and in this case, the phenomenon in which a gap is formed in the back crack 2 is further promoted as the surface is flattened, so that the existence thereof is also remarkable.

The gap between the back cracks as described above tends to increase in proportion to the absolute depth of the back crack, and when applied without drying,
Regardless of the presence or absence of curvature or the direction, as the drying progresses, the gap in the central part of the veneer that is not constrained from shrinking tends to expand more and more, but in any case, such back cracking becomes apparent. Is a factor that deteriorates the quality of the product obtained by sticking.

Furthermore, as is apparent from the fact that it is possible to easily flatten a curved veneer as shown in each of the above figures with a surprisingly small force, as is apparent from the above-mentioned veneered veneer fibers. The strength in the orthogonal direction is extremely weak, but as evidenced by the lumber products, the strength in the direction orthogonal to the fibers of the wood itself is
It is not necessarily so weak, but it has a practical strength corresponding to the plate thickness, and the weak strength in the direction orthogonal to the fiber of the veneer with back cracks is due to the existence of back cracks. Is obvious, and even if the veneer is integrally attached to another suitable plate material and used, it is a factor that reduces the strength of the product after molding.

Conventionally, such a veneer in which back cracking becomes apparent is mainly used on the inner side of the product, and in addition, in the product, the backing crack is not exposed to the front and the fiber of the veneer having back cracking is used. Since it is selectively directed to applications where the strength in the orthogonal direction is hardly hit,
As a result, the actual occurrence of back cracking is tolerated, but for example, all laminated materials such as veneer laminated materials, which are expected to be in great demand as substitutes for lumber products in the future. Align the fiber direction of veneer or most veneer in the same direction,
In the case of products that have the possibility of being used in combination by sticking together and exposing various surfaces to the front side, the deterioration of quality due to the manifestation of the back crack and the strength caused by the presence of the back crack. Can be a fatal drawback that significantly limits the application of the product.

Therefore, prior to the development of the present invention, an adhesive was inserted into the back cracks of a plurality of veneers having different water contents in order to reinforce the back cracks and to make the back cracks invisible. Then, I made an attempt to attach it to another plate material, but simply inserting an adhesive into the back crack does not improve the strength so much, and it can not be expected that the back crack will not appear. It became clear during the development process of the present invention.

That is, for example, even if the adhesive is inserted into the back crack of a curved veneer as shown in FIG. 8 and is adhered integrally with another plate through the adhesive, as described above, it is simply flattened. Since the back cracking is difficult to restore to an adhesive state by just doing it, and a phenomenon occurs in which not a few gaps occur in the back cracking portion, the adhesive effect by the adhesive is not effectively exhibited, and the strength is not improved so much. As a result, in the case of a curved single plate as shown in Fig. 10, the phenomenon in which a gap is created in the back cracked portion is promoted with flattening, so the adhesive effect of the adhesive cannot be effectively exhibited. As a result, the strength is not so improved.

It should be mentioned that the adhesive is not enough to fill the gap between the back cracks with a very general amount of use in consideration of the sticking cost, etc., and the above-mentioned result is obtained. However, since the gap between the back cracks cannot be filled, the non-visualization of the back crack cannot be achieved.

Of course, we tried to further improve the strength by increasing the amount of adhesive used, but the back cracks are narrower in the deeper part, and there are countless fine wood pieces sandwiched between them. However, uniform insertion is extremely difficult and tends to be unevenly distributed in the vicinity of the entrance, and the increase in the amount of use not only induces the inconvenience of increasing the attachment cost, but also the adhesive itself. It is well known that there is a tendency to reduce the strength of, and, for example, when tested using a urea-based adhesive, which is suitable in view of its properties and price, foaming occurs in a relatively large amount of uneven distribution. As a result, the original strength of the urea-based adhesive was not exhibited, and the strength improvement corresponding to the increased amount was not achieved.

Also, filling a gap with a large amount of adhesive tends to make back cracking invisible, but it is extremely difficult to make the color tone of the adhesive uniform to the color tone of different veneers. Therefore, when an adhesive having a different color tone is inserted into a relatively wide gap, there is also a disadvantage that it induces a phenomenon that emphasizes back cracking, and in the end, an essential solution has not been reached.

The present invention was developed by repeating insights and experiments based on the basic research as described above, and provides a sticking method that effectively reinforces back cracks and can be made non-visible. By doing so, it is intended to improve the quality and strength of the product, thereby expanding the application of the product,
Specifically, an adhesive is also inserted (including application and adhesion) into the back crack of the veneer, and while the veneer veneer is pressed in the direction orthogonal to the fiber, it is integrated with other plate materials. It is a method of sticking in a shape of sticking.

According to the pasting method having the above-mentioned structure, the single plate having the back crack is pressed in the direction orthogonal to the fiber, that is, in the state of being compressed in the direction intersecting with the back crack, Since it is attached integrally with the other plate material, even after the pressure due to external force is released, the other plate materials and the adhesive of the adhesive part will provide a reinforcing effect and maintain the compressed state almost as it is. As a result, the phenomenon in which a gap is generated in the back crack portion is regulated, and if it is referred to, the already existing gap is also closed or narrowed, so that the back crack is not manifested and the back crack occurs. The adhesive effect inserted by the adhesive is effectively exerted, and the gap is closed or narrowed, so that the adhesive is diffused into the deep portion and fills the gap. The amount used is sufficient, and the strength of the adhesive itself is not significantly impaired. The desired strength improvement is achieved along with the cost reduction, and even if the color tone of the adhesive is somewhat different, there is no risk of inducing the phenomenon that emphasizes back cracking, resulting in product quality and strength. However, it is effective because it is remarkably improved as compared with the conventional one and the application of the product is expanded accordingly.

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

Initially, the application method according to the present invention uses a brush when applying an appropriate adhesive, for example, a urea-based adhesive 10, to both front and back surfaces of a single plate 1 having back cracks 2 as illustrated in FIG. The urea adhesive 10 is also inserted into the back crack 2 by using 12, and then a pair of hot plates 4 and 5 are heated to an appropriate temperature by an appropriate heat source such as heating steam, as illustrated in FIG. 1, for example. An elevating mechanism 6 composed of a fluid cylinder or the like for elevating and lowering one of the hot plates 4 in a direction of contacting and separating with the other hot plate 5, and a pair of pressing members disposed on both left and right sides of the hot plates 4 and 5, respectively. The thin veneer 3 is attached to both the front and back surfaces of the veneer 1 to which the adhesive has been applied, to a thermocompression device having a moving mechanism 8 including a fluid cylinder or the like for forcibly reciprocating 7 in the direction of separating from and contacting each other. Introduce the semi-finished product in the state where the fiber directions are crossed and piled up, and the lifting mechanism 6 The reheating plate 4 is lowered to a desired position, for example, a position where it comes into contact with the upper veneer 3, and the pressing members 7 are moved closer to each other by the moving mechanism 8 to press the veneer 1 in the direction orthogonal to the fibers. In this state, the urea adhesive 10 is heated via the veneer 3 (while further lowering the hot plate 4 and further compressing the veneer 1 and veneer 3). The single plate 1 and the single plate 3 are integrally attached by being cured by curing.

According to such a sticking method, the veneer 1 is pressed in the direction orthogonal to the fibers, that is, in the direction intersecting the back crack 2, that is, in the direction intersecting the back crack 2. In the compressed state, since it is attached integrally with the veneer 3, the veneer 3 and the adhesive of the pasting portion will reinforce even after the pressure applied by the external force is released, As a result, the compressed state of the veneer 1 is maintained almost as it is, and the phenomenon in which a gap is generated in the back crack portion of the veneer 1 is regulated, and if it is mentioned, the already existing gap is also closed or narrowed. , The back crack is not visible, specifically, it is not visible so that it is not easy for the naked eye to identify, and the adhesive effect of the adhesive inserted in the back crack is effectively exerted, and the gap is closed. Or, by narrowing it further, the adhesive is diffused to the deep part while filling the gap. Runode, enough relatively small amount, without substantially impairing the strength of the adhesive itself, with reduction of sticking cost, improvement in strength as desired is achieved,
Furthermore, even if the color tone of the adhesive is slightly different, there is no possibility of inducing the phenomenon of emphasizing back cracking, so that the quality and strength of the product are relatively improved as compared with the conventional products.

Since the above-mentioned actions and effects extend to the inside of the product, such as when the product is subdivided and used, and when a groove / hole reaching a veneer having a back crack is formed in the product, Even if the inside of the product is exposed to the outside, it can be applied without any problem, and according to experiments, it has been confirmed that with a general amount of use equivalent to that for sticking, a veneer with a back crack can be used. Since the strength in the direction orthogonal to the fibers is improved to approach the lumber product, specifically, the bending strength is not only improved, but the holding strength of nails / screws, or the breakage strength of the ends is also included. Since the strength is improved, it can be applied to applications that make use of the strength, and it is effective because the applications of products are expanded as a whole.

In the embodiment illustrated in FIG. 2, a stopper 9 is provided at one end of the hot plate 4 which is lifted and lowered by a lifting mechanism 6 in a direction in which the hot plate 5 is moved toward and away from the hot plate 5.
On the side opposite to the above, a thermocompression device including a pressing member 7 reciprocally moved in the direction of the arrow by a moving mechanism 8 is used,
In the same manner as in the above-mentioned embodiment, a semi-finished product in which thin veneers 3 are laminated on both front and back surfaces of the veneer 1 on which an adhesive has been applied with the fiber directions intersecting each other is introduced into the hot-pressing device, and the hot plate 4 is desired After being lowered to the position, the urea plate 1 is pressed through the single plate 3 in a direction orthogonal to the fibers by pressing from one side by the pressing member 7 and stopping by the stopper 9. This is an example in which the veneer 1 and the veneer 3 are adhered by heating and curing the adhesive 10, and even in this case, as a result of the phenomenon in which a gap is generated in the back crack portion, Similarly effective adhesion is achieved, but the back crack has a characteristic that the cross-sectional shape bends into a substantially V shape as shown in the drawing from the process of its formation. When pressing only from above, it is recommended to press from a direction that promotes a substantially V-shaped bending degree as shown in the figure. It is easy, a and advantageous because averaging.

The above is a specific outline of the sticking method according to the present invention,
In order to further clarify the gist, the individual requirements will be described in more detail below.

First, there are no particular restrictions on the veneer having back cracks, and various shapes and water contents can be targeted. However, for example, when the veneer is used without being dried as described above, back cracking may become apparent eventually, so it is easy to prevent it by increasing the degree of pressurization in advance.
In consideration of adhesiveness and the like, undried ones are not necessarily suitable, but on the other hand, once the gap between the back cracks is fixed during the drying process, closing is not easy and a large amount of pressure is required for closing. So, it is not optimal even if it is almost dry.

Therefore, as usual, use a dried product with a water content of about 7 to 16%, in addition to a very general usage, prepare a water content of around 30% at which contraction becomes noticeable or close to it. Use a dried product, and if necessary, heat it to the adhesive at the same time as applying, or separately after heating,
Experiments in the development process of the present invention revealed that it was practical to forcibly re-dry to the desired water content or to naturally dry to the equilibrium water content after reinforcement. Also, the degree of pressurization in the direction orthogonal to the fiber may be appropriately selected in consideration of various conditions such as the drying rate of the veneer, the width of the gap, the amount of the adhesive used or the intended use of the product. Therefore, it is not always necessary to pressurize the gap until it is completely closed, and the point is that it fits the application of the product.

On the other hand, as the other plate material used in the present invention, a plate material that can maintain the compressed state of a single plate having a back crack almost as it is by combination with an adhesive is sufficient, and a single plate material having no remarkable back crack is sufficient. In addition to boards of the same quality, such as boards, veneers with marked back cracking, or wood-based boards other than veneers consisting of plywood, particle board, hardboard, etc., for example, gypsum board, synthetic resins, metal boards -Plate materials in a broad sense including heterogeneous plate materials such as paper and cloth are almost applicable, and they may be appropriately selected from them and may be used alone or in plural, and it is not always necessary to be a single sheet, When using a veneer having significant back cracking as another plate material, it is desirable to adhere it in a state where it is pressed in the direction orthogonal to the fibers in the same manner to make the back cracking non-visible. Insert the adhesive into the back crack of the veneer , Is more effective if also reinforced the single plate.

Furthermore, as the pasting form of the other plate material, in addition to the form of the above-mentioned embodiment, as shown in, for example, FIG. 11 or FIG. A plate material such as substantially the same veneer as veneer 1) is attached to only one side,
Alternatively, as illustrated in FIG. 12, for example, the sheet may be attached to both the front and back sides, but the thickness of each plate (single plate 3 and single plate 11) may be different, and may be appropriately selected as necessary. There are no particular restrictions.

On the other hand, as the adhesive to be inserted into the back crack, urea-based adhesives (including co-condensation resins such as urea melamine co-condensation resins) used in the manufacture of plywood and various boards are available. Therefore, even if the veneer with back cracking has a somewhat high water content, it is effective if the water content of the adhesive is vaporized after application and adhesion is performed. However, it is not limited to this, and it is possible to use various known adhesives such as other thermosetting adhesives, room temperature curable adhesives, thermoplastic adhesives, wet curable adhesives, etc. It may be selected according to desired conditions and may be used alone or in plural, but it is preferable that it has good diffusivity in view of the shape of the back crack. Also, there is no particular limitation on the adhesive for sticking, and it is in accordance with the description of the adhesive to be inserted into the back crack, but it is convenient to use the same kind for both.

The means for inserting the adhesive is not limited to the brush application as in the above-mentioned embodiment, and means for spraying by using the sprayer 13 as illustrated in FIG. 6 or illustrated in FIG. As described above, a rotatable roll 14 including a plurality of thin round blade-shaped collars 15 having a large number of adhesive flow holes 16 at arbitrary intervals in the axial direction, and stretched along the outer periphery of the roll 14. With the linear body 17 composed of piano wire, fishing line, etc., the container 19
Even if the insertion means is such that the veneer 1 is sandwiched and conveyed so as to be submerged in the adhesive 10 accommodated in, and the amount of application to both the front and back sides is regulated by the slitter 18, it is important to note that If you can insert the desired amount of adhesive in the crack,
Any insertion means may be used, but upon insertion, once the veneer plate is positively curved and the back crack is opened, insertion is facilitated, as illustrated in each of the above embodiments. It is practical and preferable from the viewpoint of equalization of insertion into each back crack. Although illustration is omitted, if necessary,
Once the surplus is removed from both the front and back sides after insertion, the adhesive for sticking can be applied separately, or the adhesive for sticking can be applied to the other plate side, so that different types of adhesive can be applied. It is also possible to use agents.

Further, as a device used for sticking a single plate having a back crack to another plate material through an adhesive in a state of being pressed in the direction orthogonal to the fiber, the device having the configuration as in the above both embodiments The structure is not limited, and various structures can be used, including the device described later.The structure can be configured according to the properties of the adhesive, the shape of the veneer, etc. In a state where a single plate having is pressed in a direction orthogonal to the fibers,
Any material can be used as long as it can be attached integrally with another plate material via an adhesive.

When a single plate having a back crack is pressed in the direction orthogonal to the fibers, if the single plate buckles, the pressure will be incomplete and uneven, so it is desirable to prevent it. When the plate material of (1) has sufficient rigidity to prevent buckling, it is preferably regulated by the plate material or by the hot plate in both of the above-mentioned Examples, and the like. Although it is effective to prevent buckling by arranging members that can directly or indirectly control buckling on both front and back sides, it is possible to control buckling on the entire surface of a single plate with back cracks. If the members to be obtained are brought into contact with each other to control the buckling, a frictional force is generated over the entire surface. Especially, when the width of the single plate in the direction orthogonal to the fibers is relatively wide, the friction Due to the braking caused by the force, the pressure applied in the direction orthogonal to the fibers may become uneven, so for example, It is desirable to apply the, such as will be described later deal.

That is, for example, as illustrated in FIG. 3, the heating plate 4 on one side is divided into a plurality of parts and is configured to be able to move up and down separately, and at the beginning, the distance between the heating plates 4a and 4c close to the pressing force indicated by the arrow P. T1
, In a state of being set slightly wider than the contact distance T2 of the heating plate 4b far from the pressing force, after pressing the single plate having the back crack in the direction orthogonal to the fiber, the distance T1 becomes the distance T2. The hot plates 4a and 4c are further lowered so as to be aligned to perform the attachment, or the hot plates 4 are configured to be tilted arbitrarily as illustrated in FIG. 4, and the pressing force indicated by the arrow P is initially set. In a state in which the hot plate 4 is tilted so that the distance T3 between the hot plates 4 and 5 close to is slightly wider than the contact distance T4 on the stopper 9 side, the single plate having the back crack is placed in the direction orthogonal to the fiber. After pressurization, the interval T3
It is desirable to equalize the pressurization by taking measures such as further lowering the side closer to the pressing force of the hot plate 4 so as to be aligned with the interval T4 and performing the attachment.

Further, although not shown in the figure, initially, while partially controlling the buckling, a single plate having a back crack is pressed in the direction orthogonal to the fiber, and then the buckling is performed by compressing and heating over substantially the entire surface. In order to implement it separately from the regulation of the above, it is also possible to configure members and mechanisms having different functions by interleaving each other so that the frictional force is generated only locally in each area. It is effective for the purpose of bonding, or when another plate material is attached to one surface of a single plate having back cracking using a room temperature curable adhesive, for example, an elastic member such as a rubber plate is stretched in advance. It is also effective to release the expansion of the elastic member and pressurize it uniformly from the surface after pressing it against a single plate having back cracks at the same time. If the braking caused by is positively utilized, for example, in the device of the embodiment illustrated in FIG. Short, it is also possible to perform good pressure, or for example, by combining the known continuous press or the like, it is not impossible to continuously extruded attached to Tokoroten expression.

According to the sticking method of the present invention, which is based on the above-mentioned various elements, it is extremely thick (for example, 10
mm or more) is effective because it can very effectively treat a veneer having a back crack, including veneer, and enhance its practical value. The practical effect of the present invention on the veneer-related industry is It is extremely large.

[Brief description of drawings]

The drawings are for explaining the present invention, and FIGS. 1 and 2 show a state in which a single plate is pressed integrally in a direction orthogonal to the fibers and is integrally attached to another plate material. FIGS. 3 and 4 are side explanatory views of other thermocompression devices, and FIGS. 5 to 7 are diagrams for explaining a state in which an adhesive is inserted into a back crack of a single plate. A side view, FIGS. 8 and 10 are side view views of a single plate, FIG. 9 is a side view of a product stuck by a conventional sticking method, and FIGS. 11 and 12 relate to the present invention. FIG. 13 is a side view of the product stuck by the sticking method, and FIG. 13 is a perspective view of the product stuck by the sticking method according to the present invention. 1 ... Single plate with back cracking, 2 ... Back cracking, 3 ... Thin single plate, 4,5 ... Hot plate, 6 ... Lifting mechanism, 7 ... Pressing member, 8 ... Moving mechanism, 9 ...... Stopper, 10 …… Adhesive, 11 …… Veneer that had remarkable back cracking, 12 …… Brush, 13 …… Sprayer, 14 …… Roll, 15 …… Bill, 16 …… Adhesive Circulation hole, 17 …… Linear body, 18 …… Slitting machine, 19 ……
Adhesive container

Claims (9)

[Claims] 1. When bonding a veneer veneer having back cracks and another plate material with an adhesive, the adhesive is also inserted into the back cracks of the veneer veneer having back cracks. A method for sticking a veneer veneer having back cracks to another plate material, which is characterized in that the veneer veneer having back cracks is stuck in a state of being pressed in a direction orthogonal to the fibers. 2. A method for adhering a veneer veneer having back cracks to another plate material according to claim 1, wherein the veneer veneer is used as another plate material. 3. A method for adhering a veneer veneer having back cracks to another plate material as set forth in claim 2, wherein a veneer veneer having no noticeable back cracking is used as another plate material. 4. A method for adhering a veneer veneer having back cracking to another plate material according to claim 2, wherein a veneer veneer having remarkable back cracking is used as another plate material. 5. A veneer veneer having back cracks according to claim 1, wherein a wood-based plate material other than veneer veneer composed of plywood, particle board, hard board, etc. is used as another plate material. How to attach it to other board materials. 6. A veneer having a back crack according to any one of claims 1 to 5, wherein another veneer is attached to both front and back surfaces of a veneer veneer having a back crack. How to attach a veneer to another board. 7. A back crack according to any one of claims 1 to 5, wherein the veneer veneer having a back crack is provided with another plate material on one surface thereof. How to attach veneer veneer to other board. 8. A veneer veneer having back cracks is pressed in a direction orthogonal to the fibers until the gap between the back cracks is completely closed, and any one of claims 1 to 7 is claimed. A method for attaching a veneer veneer having a back crack described in 1 above to another plate material. 9. A veneer veneer having back cracks is pressed in a direction perpendicular to the fibers to such an extent that the gap between the back cracks is filled with an adhesive, and the veneer veneer is pressed against the fibers. A method for adhering a veneer veneer having a back crack described in one item to another plate.