JPS5917924B2 - Drying method for horizontal stripping of raw veneer - Google Patents

Description

[Detailed description of the invention] The present invention relates to a method of horizontally stripping and drying a small raw veneer.

Since horizontal stripping of raw veneer can greatly save labor in the plywood manufacturing process, many methods have been developed to date, and in particular, hydrophilic adhesives such as urethane resin adhesives have been developed. Since then, it has become possible to firmly join green veneers, and various methods of horizontal stripping using hydrophilic adhesives have been proposed and tried.

However, even though hydrophilic adhesives have been developed, horizontal stripping of green veneers still has problems with adhesive T, and the major problem is that the horizontal stripping has to be dried. Because of this, the current situation is that side-splitting drying of raw veneer has not yet been put into practical use in plywood factories.

゛Hydrophilic adhesives are adhesives that react with water to gel and harden, so they have the advantage of being able to join green veneers, but current hydrophilic adhesives react with water and gel. It takes several minutes for it to turn, making it impossible to achieve highly efficient horizontal stripping.Also, it reacts with water in the air and turns into a gel, so the only way to use it is to store it in an airtight container. There are drawbacks such as difficulty in applying this to green veneer and high price, and there is still no effective method for horizontally stripping green veneer using this type of hydrophilic adhesive. It has not been put into practical use.

In addition, it is necessary to dry raw veneer that has been cut horizontally, and there are two methods for drying: one is to cut the veneer to the specified size in anticipation of shrinkage due to drying, and the other is to dry it as a continuous strip and dry it as desired. There is a method of cutting the veneer to a standard size, but in the former case, each raw veneer has a difference in shrinkage rate, and cutting to a predetermined size in anticipation of shrinkage is done by cutting the raw veneer to the maximum size in order to prevent cuts. This is done on the basis of shrinkage, so in most cases the dimensions of the dried veneer will be longer than the desired standard size.
This reduces the yield and requires extra adhesive in the gluing process.

In the latter case, since it is cut after drying, it does not have the above-mentioned disadvantages, but if it is dried in a long continuous strip, shrinkage stress will concentrate on fragile small and medium veneers or areas with small cracks.
This has the drawback that band-shaped tears or large cracks occur, and reprocessing thereof is time-consuming and yields are reduced.

Furthermore, since conventional drying is carried out while transporting the side-splitting green veneer using rolls or wire mesh, the shrinkage of the veneer that occurs during transport and the dynamic movement of the rolls or wire mesh that hold the veneer are also important. There were drawbacks such as large cracks or tears in the veneer caused by the action of external forces, and the pieces that were laterally torn apart to disintegrate.

The present invention has been made in order to eliminate these drawbacks of the conventional method, and the purpose of the present invention is to dry small and medium-sized brittle veneers produced from Panky wood (brittle core wood) by drying with almost no external force applied. It dries without any problem even if the material is dry, and it also makes it possible to cross-split small and medium-sized veneers using hot melt adhesive and yarn, and since drying requires almost no external force, the yarn The hot melt adhesive applied to the veneer remelts due to the heat during drying, and the holding power of the yarn to the veneer surface decreases, causing the side-stripped material to decompose or the yarn to separate from the veneer surface. This means that the side-stretched state is always maintained.

Since hot-melt adhesive is used as the adhesive, its rapid adhesion properties enable highly efficient cross-splitting of small to medium-sized veneers, and the low price and ease of handling of hot-melt adhesive make it possible. It has many advantages over conventional methods, such as gentleness and low running costs due to the use of only yarn and hot melt adhesive.

Another object of the present invention is to use a wicket conveyor to dry side-splitting fresh veneer with almost no external force applied, thereby making it possible to carry out the process from side-splitting to drying and transporting to the subsequent process in one step, thereby improving the plywood manufacturing process. The aim is to contribute to labor saving.

Furthermore, by preheating the surface of the raw veneer to which the threads are fixed, the present invention enables the use of a low-melting-point, inexpensive hot-melt adhesive, which reduces running costs and allows the raw veneer surface of the threads to be fixed to a lower temperature. The purpose is to securely and firmly attach it to the surface.

Another object of the present invention is to close the gap between the abutting surfaces caused by the difference in shrinkage between the veneer and the yarn, and firmly rejoin the yarn with a hot melt adhesive, thereby fixing the yarn to the surface of the veneer. Regardless of whether the veneer is simply horizontally spliced, post-processing, such as gluing, is to obtain a firmly joined horizontally spliced veneer that does not pose any problem in handling during the process.

Furthermore, it is an object of the present invention, when cutting a green veneer that has been laterally split into a continuous band shape into a predetermined size, to cut the raw veneer into a length that is slightly longer than an integral multiple of the desired standard size, and then cut the raw veneer into a continuous strip. Regardless of whether green veneer is cut to a predetermined size, it is possible to turn the entire amount of horizontally stripped small and medium-sized green veneer into the desired fixed size and dry-stripped veneer, and it is possible to reduce the yield. It's about measuring improvement.

The method of the invention will be explained below by means of an embodiment shown in the drawings.

The carry-in conveyor 1.1', which consists of upper and lower endless bands, forcibly feeds small and medium green veneers A in a conveying direction F perpendicular to the fibers (feeding drive device not shown). is provided with pressurizing bodies 2, 2' that press the upper and lower endless bands from their backs, respectively, and the pressurizing bodies 2, 2' convey the green veneer A more forcefully, and the pressurizing bodies 2, 2' It disappears at the stop line XX near the end of 2'.

The colliding conveyor 3.3' consisting of upper and lower endless belts forms a conveyance path for the green veneer A following the carry-in conveyors 1 and 1', and its tip is made to almost coincide with the stop line XX. In addition, the colliding conveyor 3゜3' forms a conveyance path for the green veneer A that runs freely without being forced to feed, and brakes the green veneer A by the frictional resistance of the bearing built into the rotating wheel on which the endless belt is stretched. The green veneer A
The end faces of the two are brought into contact with each other.

That is, the green veneer A conveyed by the incoming conveyors 1, 1' is moved by the disappearance of the feeding force of the incoming conveyors 1, 1' and the colliding conveyor 3. Due to the braking action of the car, the rear end is moved to the stop line
-X, and then the carry-in conveyors 1, 1'
The raw veneer fed by the front end moves forward while pushing the rear end of the stopped raw veneer, and during this time, the end surfaces of the successive raw veneers collide with each other, and this collision state Similarly, the rear end of the raw veneer at the rear almost coincides with the stop line XX and stops.

In this way, the small and medium green veneers A that are sequentially conveyed by the carry-in conveyors 1 and 1' are brought into contact with each other at the stop line The edges of the narrow raw veneers are abutted against each other.

The yarn pasting device 4 applies a yarn 5 coated with hot melt adhesive H.
are fixed to the surface of green veneer A whose end surfaces are abutted in a direction perpendicular to the fibers, thereby forming a continuous band-shaped horizontally spliced green veneer.

In the example, five sets of thread pasting devices were used, and three
Each thread pasting device 4 has a glue tank 6 that stores the net melt adhesive H and keeps it in a heated and molten state, and guides the thread 5 into the glue tank 6. a coating roll 7 for applying the hot melt adhesive H thereto, a winding frame 8 for the yarn 5, and the yarn 5 to which the hot melt adhesive H has been applied.
It is composed of an adhesion roll 9 that adheres the material to the surface of the green veneer A at the positions of the matching conveyors 3 and 3', and the adhesion roll 9 rotates as the green veneer A travels, and this rotation lets out the yarn 5. At the same time, this was attached to the green veneer surface in a direction perpendicular to the fibers, and the hot melt adhesive H was rapidly cooled and solidified to fix the yarn 5 to the green veneer surface, so that the end surfaces of each other were abutted. The green veneer is formed into a continuous band.

As the yarn 5, an appropriate material such as synthetic resin fiber such as Tetron or nylon or glass fiber is used, and the attachment of the yarn 5 to the surface of the raw veneer is achieved by attaching it to the front and back surfaces of the raw veneer as in the example. It is also possible to apply it only to the front or back side.
The number of strips is not limited to five, and can be appropriately selected depending on the thickness of the raw veneer, the length in the fiber direction, etc.

Hot melt adhesives H currently on the market are broadly divided into those using EVA (ethylene-vinyl acetate copolymer) as a pace polymer and those based on polyamides, and the former are relatively inexpensive and often have a low melting point. It is a general adhesive, and the latter is relatively expensive, often has a high melting point, and is used for special purposes.

EVA type products are used at a temperature of about 120°C to 150°C, and when applied to the threads 5 and attached to the raw veneer surface, the heat causes the raw veneer part to which the threads are attached. The hot melt adhesive cannot fully evaporate the remaining moisture, and the hot melt adhesive does not anchor to the green veneer sufficiently. needs to be removed.

On the other hand, polyamide-based materials have a working temperature of 180℃.
At such a high temperature, the moisture evaporates due to the heat and the threads are sufficiently fixed to the raw veneer surface even if the surface of the raw veneer is not heated in advance.

When using the EVA-based hot melt adhesive H, which is inexpensive and has a low melting point, the Nioite of the present invention is
A heating body 11 having a built-in heater 10 is disposed at a location,
The surface of the raw veneer to which the threads 5 are fixed is preheated in the form of a band, and moisture on the surface of the raw veneer is removed.

A cutting device 12 is disposed at the end of the colliding conveyor 3, 3', and the cutting device 12 includes a cutter 13, a receiving blade 14, and a cutter 13.
The operating mechanism 15 is for cutting a continuous strip of green veneer into a predetermined size.

A delivery conveyor 16 is disposed following the cutting device 12, and the delivery conveyor 16 runs at a constant speed and transports the green veneer formed into a continuous band on the colliding conveyors 3, 3'. be.

A detector 17 is provided at the discharge conveyor 16, and the detector 17 forms a continuous band.
The front end of the green veneer being conveyed above is detected and the signal is transmitted to the actuating mechanism 15, which cuts the continuous band-shaped green veneer into a predetermined size.

In this case, cutting to a predetermined size is done by cutting the veneer to the desired standard size (the standard size of the dried veneer, and the size used when forming plywood in the gluing process) to the amount of shrinkage (generally 7 mm in the direction perpendicular to the fibers of the veneer).
It is set to be somewhat longer than an integral multiple of the length (with shrinkage of around %).

As mentioned above, this is to prevent a decrease in latch due to the difference in the shrinkage rate of individual veneers. (can be made into an integral multiple) plus the amount of shrinkage.

The side-splitting raw veneer A' cut into a predetermined size is continued to be conveyed by the carry-out conveyor 16, and its front end is connected to the detector 17.
When the conveyor 16 reaches the position of the detector 18 disposed at the rear thereof, the conveyor 16 temporarily stops in response to the signal.

A wicket conveyor 19 is disposed on the side of the carry-out conveyor 16, and the wicket conveyor 19 has a plurality of upper and lower rotary wheels 21 on upper and lower shafts 20 and 20' parallel to the conveyance direction of the carry-out conveyor 16, respectively. .21' is attached, an endless band 22 is stretched between the upper and lower rotating wheels 21 and 21' that face each other, a large number of arm bodies 23 are attached to each endless band 22, and each endless band 2
The phases of the arms 23 attached to 2 are made to match, and a side-splitting raw veneer N cut to a predetermined size is placed and supported on the arms 23.

The raw veneer λ is placed on the arm body 23 by moving the wicket conveyor 19 in the direction of the arrow in the figure, as shown in FIG.
In the ascending process of the arm body 23, this is done near the lower rotary wheel 21' where the gap between the arm bodies 23 that come before and after each other is wide, and therefore the conveyance surface of the carry-out conveyor 16 is aligned with the axis of the lower axis 2σ. The arm bodies 23 are aligned so that the arms 23 almost coincide with each other, and the arm bodies 23 are aligned so that the arm bodies 23 can pass across the conveyance surface of the carry-out conveyor 16.
The endless belt of the carry-out conveyor 16 on the passing side is divided as shown in FIG.

The wicket conveyor 19 is operated by an intermittent drive (the drive device is not shown) and is controlled by the detector 18.
done by.

That is, the signal that the detector 18 detects the front end of the side-splitting raw veneer A' causes the unloading conveyor 16 to be temporarily stopped as described above, and the wicket conveyor 19 is operated by one pitch of the arm body 23, and this operation is stopped. The side-splitting veneer A' on the conveyor 16 is received by the arm 23.

The wicket conveyor 19 is surrounded by a wall 24, and a fan 25 and a heater 26 are placed at appropriate positions within the wall 24.
is provided to circulate hot air within the wall to dry the side-splitting raw veneer that is mounted and supported on the arm body 23 and moved.

In this case, since the side-splitting raw veneer N moves while being supported by the arms 23, it is hardly subjected to external forces such as being conveyed while being held between rolls or wire mesh as in the conventional method. Therefore, the side-splitting raw veneer A' is simply spliced with the threads 5 fixed to its surface with the hot-melt adhesive H. Moreover, the hot-melt adhesive H is softened by the heat during drying, and the threads 5 are Even if the holding force decreases, the side-splitting condition is completely maintained, and even if the side-splitting raw veneer N is a fragile veneer like Pankey wood, it can be dried without any problem.

A discharge conveyor 27 is disposed near the lower rotary wheel 21' during the lowering process of the arm 23 of the wicket conveyor 19, and the discharge conveyor 27 is also connected to the arm 23 as shown in FIG.
It is installed in areas where there is a gap between 3 and 3.

The conveyance surface of the discharge conveyor 27 is also positioned so as to cross the running path of the arm body 23, and when the arm body 23 moves one pitch and crosses this conveyance surface, the discharge conveyor 27 transports It is transferred onto the surface.

In this case as well, the endless belt of the discharge conveyor 27 on the side through which the arm body 23 passes is also divided as shown in FIG.

When a side-splitting green veneer is dried, it contracts in the direction perpendicular to its fibers, that is, in the longitudinal direction of a predetermined dimension, and during this shrinkage, there is a difference in shrinkage between the veneer and the threads 5, and generally the threads 5 Since the amount of shrinkage is smaller than that of veneer X, there will be some gap between the abutting surfaces of adjacent small and medium veneers, and this gap between the abutting surfaces will cause defective products with tunnels. It also causes trouble in the handling of the next layer process.

In order to eliminate this drawback, the present invention closes this gap and performs horizontal stripping again using yarn and hot melt adhesive H.

That is, following the discharge conveyor 27, a forced-feeding conveyor 28 and a free-running colliding conveyor 29, which are configured in the same manner as in the case of horizontally splicing green veneers, are arranged in sequence, and the dried horizontally spliced veneer X is discharged. The threads are fed from the conveyor 27 to the conveyors 28 and 29, and the gap between the abutting surfaces is brought into close contact by the braking action of the abutting conveyor 29, and a thread pasting device 30 similar to that used for thread pasting of green veneer is installed. The threads 31 are fixed to the surface of the veneer by hot melt adhesive H in a direction perpendicular to the fibers.

The thread pasting device 30 is composed of a glue tank 32, an applicator roll 33, a winding frame 34 for the thread 31, and a pasting roll 35 disposed at a position of the conveyor 29. The yarn 31 is let out by the rotation of
The threads 31 are fixed to the surface of the veneer using the hot melt adhesive H.

The veneer that has been stripped by the thread 31 with the gap between the abutting surfaces close together is cut into horizontally stripped veneer A1 of standard size and the remaining horizontally stripped veneer A1 by the cutting device 36 installed at the rear of the conveyor 29. It is cut into veneer A2.

The cutting device 36 is a blade 37, the receiver is a roll 38, and the operating mechanism 3
9, and an output conveyor 40 is located downstream of the cutting device 36.
A detector 41 for detecting the standard size is provided at the position of the output conveyor 40,
When the front end of the peeled veneer transferred to the exit conveyor 40 activates the detector 41, the signal is transmitted to the actuating mechanism 39, and the cutter 37 converts it into a horizontally peeled veneer A1 of standard size. The inner side-splitting veneer A2 is cut.

The cut horizontally spun veneers A1 and A2, for example, are pushed out from the output conveyor 40 to the side and are deposited as piles A/1 and A/2, and the horizontally spliced veneer A1 of standard size is left as is with glue. The attachment is configured for plywood in the process, and the horizontally spliced veneer A2 is joined using a horizontal splicing machine, for example, by applying hot melt adhesive to the mating surfaces, and then cut to a standard size. It is made of horizontally-seamed veneer.

As described above, the present invention performs cross-splitting of raw veneer using only hot-melt adhesive and thread, so that it is possible to perform cross-splitting of raw veneer with high efficiency and low cost, and to form continuous strips by horizontally splicing. The material is cut into a predetermined size that is slightly longer than an integral multiple of the length of the desired standard size plus the amount of shrinkage, and these are supported on the arms of the wicket conveyor in a state where almost no external force is applied. Because it is supported and dried, even fragile raw veneers such as punky wood can be dried without any problems, and even horizontally spun raw veneers that are spliced together using only threads and hot melt adhesive can be dried. Also, it is possible to dry the material with the horizontal stripping state completely maintained, and after the abutting surfaces caused by drying shrinkage are brought into close contact, you strip it and cut it to the desired standard size. As a result, the entire amount of raw veneer can be made into a product, which improves latching properties, eliminates defective products, and provides a strong side-splitting veneer that can withstand handling, etc., and further improves the side-splitting process of raw veneer. It has various effects such as being able to save a lot of labor, making a great contribution to the plywood industry.

BRIEF DESCRIPTION OF THE DRAWINGS The drawings show an embodiment of the method of the present invention, in which FIG. 1 is a side view, FIG. 2 is a plan view, and FIG. 3 is a front view of the wicket conveyor section. 1.1'... Loading conveyor, 3,3'...
... Collision conveyor, 4,30... Thread pasting device,
5, 31... Yarn, 9.35... Sticking roll, 11... Heating body, 12.36...
... Cutting device, 16 ... Carrying out conveyor, 17.
18.41...Detector, 19...Wicket conveyor, 23...Arm body, 27...
...Discharge conveyor, 28... Forced feed conveyor, 29... Free running conveyor, A...
・・Small and medium-sized raw veneer, A′・・・・・・Horizontal raw veneer, A
″・・・Dry side-splitting veneer, A1・・・Standard-sized horizontally-splitting veneer, A2……Horizontal-splitting veneer in regular size, H...・Hot melt adhesive.

Claims (1)

[Scope of Claims] 1. A large number of small width raw veneers are conveyed in a direction perpendicular to their fibers, and their end surfaces are brought into contact with each other, and the front or back surface or both front and back surfaces of the raw veneers whose end surfaces are brought into contact are A plurality of yarns coated with hot melt adhesive in a direction perpendicular to the fibers are heated in advance at the core portion or fixed unheated to form a continuous band, and the continuous band-shaped raw single wave is applied to the desired shape. A horizontally spun raw veneer of a predetermined size is obtained by cutting it into a length slightly longer than an integral multiple of the length of the standard size plus the amount of shrinkage, and the horizontally spliced raw veneer is supported in a state where almost no external force is applied. A method for horizontally stripping and drying raw veneer veneer, characterized by drying it by placing it on the arm of a wicket conveyor and running it inside a wall where hot air circulates. 2. A large number of small width raw veneers are conveyed in a direction perpendicular to their fibers, and their end surfaces abut each other, and the front or back surface or both front and back surfaces of the abutted raw veneers are perpendicular to the fibers. A plurality of yarns coated with hot melt adhesive in the direction are heated in advance at the core part or fixed unheated to form a continuous band, and the continuous band-shaped green veneer is shrunk to a desired standard size. Cut to a length slightly longer than an integral multiple of the length of The dry cross-splitting veneer is dried by running it inside the wall where hot air circulates, and the abutting surfaces separated by the drying shrinkage of the dry cross-splitting veneer are brought into close contact with each other and a plurality of strips are coated with hot melt adhesive. A small width raw veneer characterized by fixing threads on the surface in a direction perpendicular to the fibers, and then cutting the yarn into horizontally spliced veneers of a desired standard size and horizontally spliced veneers of a desired size. How to dry a board horizontally.