JPS5847966B2 - Continuous LVL manufacturing method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for producing continuous LVL by laminating and bonding a plurality of adhesive-coated veneers in the same fiber direction, which is effective in saving energy, resources, and man-hours. It provides a manufacturing method.

In general, LVL (Laminated Veneer
Lumber (laminated veneer material) refers to a thick board made by bonding multiple veneers in a continuous manner in the fiber direction in multiple layers, and this is used as a material for cutting into square lumber or square boards. However, rather than sawing logs into square timbers or boards,
The LVL method, in which logs are peeled with rotary lace and laminated and bonded together, has a higher yield of logs, and long logs can be continuously obtained from short logs.

Canada is popular due to its advantages such as less variation in material due to the dispersion of defects, not using the low-quality core of logs, easy production of dried products, and ease of chemical treatments such as antiseptic, insect repellent, and fire prevention. Manufacturing methods are being developed in the United States and other countries, and are attracting a lot of interest in various fields in Japan as well.

At present, the following four methods have already been proposed (wood industry, V
ol. 28-9, p396-397'), but each has its own problems and has not yet reached the practical stage.

(1) Semi-continuous FPL method (Semibatch F.P.L-Press-
(Lam Process) This involves peeling a log heated in a heating bath at around 40°C into a relatively thick veneer using a rotary lace, then cutting it with a clipper and inserting it into a multi-stage hot press dryer.

The dried veneer is temporarily stored in a heat insulation box at lOO℃.
Keep at nearby temperature.

This preheated veneer then passes through a glue extender, is coated with adhesive on one side, enters an assembler, is successively stacked to properly distribute the butt joints of the lamina, and is sent to a continuous press laminator where it is cold pressed. It becomes LVL.

However, this method has the problem of requiring the development of a powerful continuous press laminator, and has not yet been put to practical use.

(2) Continuous FPL method (Continuous FPL Press-
Lam Process) This is a method in which a continuous press dryer is placed in place of the multi-stage press dryer and a continuous assembler is placed in place of the veneer assembler in the process (1), and is more efficient than the method (l). There is no need for a heat insulating box, the process runs quickly, there is no need to pre-cure the adhesive, and a higher temperature veneer can be used, allowing the use of cheaper phenolic adhesives and shortening the pressing time.

However, the development of such continuous press dryers and continuous assemblers is delayed, and it is thought that practical application will be even more difficult than (1).

(3) Continuous LVL Process If the temperature of the veneer is not high, it will take a long time to heat press the multi-layered LVL at once using a hot press, but first the center veneer 2
If the sheets are hot-pressed and then one sheet is added on each side of the sheet one after another, the inside will harden somewhat faster after the second press, so the overall pressing time can be reduced considerably.

According to this principle, the veneers are fed through an endless belt press in the direction of the fibers, with the ends of each end one after the other, and one more endless belt press is placed each time a veneer is added on both sides in the thickness direction of the LVL. However, the adhesive is applied just before each endless belt fresse.

This method also uses an expensive endless belt press as the first and second press.
, third, etc., and even if such a high-performance high-pressure endless belt press were developed, it would pose a major problem in terms of equipment cost.

(4) Intermittent LVL process
) This is continuous LVL pr of (3)
This is a version of the Ocess that is adapted to reality, and uses a single-stage intermittent press instead of a high-pressure endless press, which has not yet been developed.
, second, and third, and there is a problem of inefficiency considering the equipment cost.

The inventors have already proposed these Processes.
As mentioned above, there is a problem with the practicality of s, so after various studies, we decided to change the laminated shape of the adhesive-coated veneers so that the take-out side of the press has a reverse step-like shape and the insertion side has a step-like shape, as shown in Figure 1. None, by pressing with the attached press of the stepped and reverse stepped molds (3 and 4) that match the laminated shape of the veneer, both ends of the wood are pressed with a large number of reverse stepped and stepped shapes, respectively. It has been found that a long LVL can be obtained by obtaining the LVL material 5 and rejoining the material at the step part and the reverse step part one after another in the next step.

As a result of further intensive study based on these findings, the inventors made the laminated shape of the adhesive-coated veneers step-like on the insertion side of the press, and attached an inverted step-shaped stopper mold that matches the shape. By pressing with a press, an LVL material with a step-like end on the insertion side is obtained on the press clamping plate, and when the press is opened and closed, the material is moved on the clamping plate of the press in the direction of the take-out side of the press (
(progressing direction) so that the stepped end is located near the take-out side, and then a new adhesive-coated veneer is placed against each veneer in the stepped end, and the press insertion side is placed in the pressing mold. They are laminated and pressed together in a stepped manner to fit.

This is a perfect example of the present invention, which obtains continuous LVL by repeating such steps.

Note that the parallel plywood currently produced in the plywood industry is simply laminated and glued together with the fiber directions of the veneers making up the plywood parallel to each other, and the product can only have the same length as the length of the veneer in the fiber direction.

The method of the present invention not only laminates and adheres veneers in the thickness direction, but also makes the butt side ends continuous in the fiber direction in a butt-like manner. This is a method to obtain a product of L.
This is different from VL.

Next, the present invention will be explained in more detail.

The veneer used in the present invention is mainly obtained by peeling raw wood with a rotary lace, and the thickness is between 1.5 and 2.
It is 0mm.

If the thickness is thin, cracks on the back of the veneer will be reduced and a flat surface will be obtained, but the number of layers will increase and the cost will increase.
It is necessary to make a selection by taking into account the stripping technique, purpose of use, cost, etc.

In addition, veneer has a moisture content of about 30% to 100% when it is peeled, and as it is, it cannot be joined without using an expensive epoxy or urethane adhesive for wet wood, and the product may shrink due to drying. Because of these problems, it is thought that it is often used after being dried with a dryer, but the optimum moisture content may be selected depending on the purpose.

The higher the temperature of the veneer, the faster the adhesive will harden and the higher the productivity, which is advantageous, but in general the curing speed of the adhesive is 6.
If the temperature exceeds 0 to 80°C, the speed increases significantly, so it is preferable to use the temperature at 60°C or higher, more preferably 80'C or higher, and particularly preferably 100°C or higher, but the time from applying the adhesive to pressing It is necessary to shorten the time as much as possible, and it is desirable to increase speed through mechanization.

The length of the veneer (length in the fiber direction) is specified by the length of the raw wood to be peeled with the rotary race, but it does not need to be longer than the pressing plate of the press, and the length of the lower pressing plate of the press L1 ′
The length I, , /I,2/ may be obtained by subtracting the length L2' of the first stage remaining in the twisting die or the press of the LVL that has already been moved to the take-out side.

Or if you use a longer press (L1'-L2/
)÷n (n = an integer such as 2.3 or 4, which indicates the number of veneers that can be lined up horizontally) can be used.

In addition, inexpensive short logs and end logs, which were conventionally considered waste materials, may be joined and peeled to a predetermined length, and the end of the veneer may be formed into an interlocking shape such as a scarf or zigzag.
It is also a preferable method to use a material that is vertically joined by a method that provides sufficient strength.

Furthermore, by forming the end of the veneer into a zigzag shape or a scarf shape (FIG. 3), the joint state is superior to that of a simple butt joint, and the strength of the LVL is also improved, which is preferable.

However, between the downward scarf on the insertion side in Figure 3 and the upward scarf on the opposite side, the downward scarf is superior in terms of ease of butt jointing, but if the scarf distance is long in either case, a matching type is available. Otherwise, there will be a lack of pressure on the veneer under the scarf section.

A flat plate press is a press in which the pressing surfaces of the upper and lower pressing plates 1 and 2 are flat, as shown in Figures 1 to 3, and are generally used for plywood, particle boards, hard boards, and melamine decorative boards. It is possible to use a press that is used to press-manufacture flat plate products such as phenolic laminates and phenolic laminates.

Regarding the names of "take-out side" and "insertion side," the side of the press from which the pressurized object is taken out is called the "take-out side," and the opposite side is called the "insertion side." is the same).

Therefore, the "insertion side" may be the same as the side where the veneer is actually inserted, or the veneer may be inserted in a direction perpendicular to the fiber direction due to factors such as factory work space, work efficiency, and reduction of press stroke. There are cases where they do not match, such as when

Additionally, as ancillary equipment for the press, an endless belt is installed on the lower clamping plate to quickly move the object to be pressed, and a high-speed belt is installed on the lower clamping plate to quickly stack adhesive-coated veneers on the press clamping plate. It is preferable to install an assembler or the like.

The stepped mold 3 (used only when molding the continuous LVL head, i.e. used only in the first press and removed immediately) and the reverse stepped mold 4 are made of metal, wood, plastic, rubber, or a combination of these. The height of each stair step is matched to the thickness of the corresponding veneer, and the length of the step is matched to the shift distance for each layer when laminating the veneers.

Also, a pressing mold and a clamping plate if necessary? Cushioning material can also be used between each stage of the mold.

Also, the number of stages of the pressing mold can be the same as the number of veneer lamination stages, one less, or two stages less. However, when using a pressing mold with two fewer stages, Since pressure is not applied only to the shifted part of the veneer, this veneer part is easily deformed in the direction away from the clamping plate, and if the number of stages is the same, the usable length of the press clamping plate is only the length of one stage. Because of this, it is most preferable to use a mold with one step less in practical use, except in the case of scarves.

The stepped mold may be integrally molded of metal or the like and fixed to the clamping plate, but it is preferable that it can be moved back and forth in the direction of the insertion side C and the extraction side, and furthermore, it is possible to prevent variations in the length of the veneer in the fiber direction. Since the shifting distance may not be constant, a structure may be used in which plates having the same thickness as the veneer are stacked one on top of the other, and each structure or plate may be independently shifted in the direction of the insertion side 'C and the extraction side.

The shape of the end of the veneer is usually cut at 900 degrees in the direction of the fibers, but some are cut in a zigzag pattern,
Since a scarf-shaped one can also be used, it is preferable that the resting mold can be moved forward and backward as a whole and/or for each constituent plate independently.

Adhesives that can be used in the present invention include epoxy, urethane, resorcinol, phenol, melamine,
Thermosetting resin adhesives such as urea-based, vinyl urethane-based, α-olefin-based, and zirconium-based modified vinyl emulsions, or adhesives containing one or more of these types can be used, but if the intended use of the product LVL is For outdoor use or similar conditions, it is preferable to use epoxy, urethane, resorcinol, phenol, etc. adhesives; for indoor use or similar conditions, use melane, urea, etc. It is preferable to use adhesives such as vinyl urethane-based, α-olefin-based, and zirconium-based modified vinyl emulsions.

In addition, from the viewpoint of productivity, adhesives such as resorcinol, phenol, melamine, urea, vinyl urethane, α-olefin, and zirconium-modified vinyl can be cured relatively quickly by raising the temperature of the veneer. It is advantageous because it is easy.

Melamine-based and urea-based adhesives can be cured quickly by selecting a hardening agent, and can also be cured with the main agent. By applying a method of separately applying and mixing on the veneer surface without mixing them in advance (separate coating method), it is possible to use a fast-curing curing agent that cures too quickly and cannot be mixed in advance.

Rapid curing is possible by using these methods in combination, so if highly efficient automatic lamination equipment is developed, it can be effectively utilized.

In terms of cost, epoxy and urethane adhesives are currently expensive, but those with a specific formulation can bond even veneers with a moisture content of 100% or more, and LV
Since L can be manufactured, dryer equipment is not required and there is no drying cost, so if the price of these adhesives decreases, it will become practical.

In the method of the present invention, the adhesive must be thermosetting because the product is taken out of the press while still at a high temperature. Since the LVL is cooled, a thermoplastic adhesive can be used, but as the thickness of the LVL increases, it takes a long time to cool the inside, making it impractical.

The adhesive is applied using a roll coater, a spray, a flow coater, or equipment equivalent to these, and sprays, flow coaters, etc. are effective for the above-mentioned separation coating method.

In the stacking method of the present invention, the upper surface of the stairway part of the veneer is pressed with a pressing mold, and then a new veneer coated with adhesive is loaded, so that the part pressed with the pressing mold is free of adhesive. It is preferable to leave it uncoated.

In particular, some adhesives may bond strongly to the wooden surface of the veneer, but some may not adhere well to the surface of the adhesive that has already hardened, so care must be taken.

For this reason, it is preferable to apply the adhesive only to the bottom surface of the veneers starting from the second veneer from the bottom, without applying the adhesive to the veneers in the lowest tier, and to stack the veneers one after another. In this case, a roll coater is most suitable.

When applying the top surface of the veneer using a sprayer, flow coater, etc., either turn it over and face the bottom surface, or apply the first layer of veneer (
51, 5, etc. in Fig. 2), and do not apply only to the surface corresponding to the staircase portion and the topmost veneer.

Of course, if the adhesive is of a type that is inexpensive and has no problem adhering to the adhesive-cured surface, such consideration is not necessary.

By applying adhesive to the outer surface of the front veneer and/or the outer surface of the back veneer of the LVL, and applying resin treatment to the surface at the same time as adhering the LVL, the water absorption rate from the grain surface of the veneer is reduced, and corrosion is prevented. ,
Effects such as insect control, improved appearance and aesthetics, and improved surface strength can be achieved.3 In this case, it is preferable to use an endless call plate between the press clamping plate (upper and/or lower) and the LVL. .

The method for laminating adhesive-coated veneers is to stack them in advance in a predetermined shape outside the press, and then carry them into the press by rotating an endless coal plate or an endless belt installed on the soil of the lower pressure plate 2 of the press. However, as for the shape of the three-stepped part, it is preferable to directly stack the layers to fit the stepped part of the pressed LVL on the take-out side of the lower pressing plate of the press because it shortens the process and time. The displacement distance of the end of the board is 5 to 30 times the thickness of the veneer, preferably 10 to 30 times the thickness of the veneer.
It is sufficient to increase the amount by 30 times, particularly preferably from 20 to 30 times.

However, if the end of the veneer is scarfed or zigzag processed to improve the joint strength, the shifting distance can be shortened and the pressing ability can be improved. is 8~lokg/vie, and high specific gravity materials such as birch, oak, and apitone are 10~12kg/cIit.
However, if the veneer is thick and has large curvature or undulation, it is preferable to further increase the pressure by 10 to 30%.

The pressing time cannot be easily specified because the curing time varies depending on the veneer temperature, laminated thickness, adhesive type, composition, amount of application, etc., but it should be decided experimentally in advance within a safe and highly productive range. It is.

It is preferable to maintain the temperature of the press clamping plate and the pressing mold constant using electricity, steam, hot water, hot oil, etc. Furthermore, if it is desired to measure the temperature rise within the press, application of high frequency electric energy is also effective.

In the present invention, when the press is opened and closed, the pressurized object is moved from the insertion side of the press to the removal side. It must be set within the distance to the end that can be pressurized with a predetermined pressure on the extraction side.

That is, the stepped portion is not removed from the press but remains within the take-out portion of the press.

This is to ensure that when the veneer to which adhesive has been newly applied is laminated and bonded while abutting against each step portion, sufficient pressing force is applied to exert sufficient adhesive strength.

Next, the effects of the present invention will be described.

First, Semibatch Press, Lam-Pr
Occess and Continuous Press
- Continuous press laminator in LamProcess, Continuous L V LProcess
A large number of endless belt presses, etc. in s have not yet been developed and cannot be used unless they are developed in the future, and all of them require large equipment, which poses the problem of increasing equipment costs and running costs in addition to development costs.

Intermittent L V LProces
s does not use a particularly new press, but requires the use of a large number of single-stage presses, which increases equipment costs.

In the method of the present invention, by using a simple pressing die and moving the object to be pressed from the insertion side to the removal side when the press is opened and closed, continuous LVL can be produced with a single flat press, which is already used everywhere. Therefore, it is significantly advantageous in terms of development cost and equipment cost.

As described above, the present invention uses a veneer coated with adhesive and a pressing die and a flat plate press to form a stepped LVL material on the insertion side on the lower pressure plate of the press, and then transfer it to the take-out side of the press. After moving, the newly coated veneers are laminated in a butt-like manner on the stepped portion, pressed together, and then these operations are repeated to obtain a continuous long LVL.This is an industrially extremely effective method. be.

Examples will be described below.

Example l (Figure 2) Thickness: 5 mm, width: 1000 mm, length: 500, 400, 300 mm
, 200 , 100 steps 5 iron plates are inserted one sheet of cushion paper between each layer, and stacked and fixed at a shifted distance of 100 steps to form a reverse stepped mold 4 (a heating wire can be passed through the inside of the sheet) Create a vertical x horizontal = 2200im
It is attached to the insertion side end of the upper clamping plate 1 of a one-stage press having upper and lower clamping plates 1 and 2 of 1200 mm, and
The temperature was adjusted to 135°C.

A lauan log with a length of 1450-1460 mm was cut using a rotary lace with a cutting distance of 1400 mm to obtain an endless veneer with a thickness of 5.2 mm and a width of 900 mm, which was cut vertically (length in the fiber direction) with a clipper to a length of 400 mm x horizontal. It was cut into pieces of 900 mm to obtain a large number of undried regular length veneers.

That veneer? Pressed with a multi-stage hot press at 30℃, thickness x vertical x horizontal]==5
mtn(D) A large number of dry hot veneers 5, to n were obtained.

The veneers 5, to n were taken out from the hot press and used as needed.

A mixture of 100 parts by weight of alkali phenol formaldehyde resin (Slight Resin PR-9300 manufactured by Sumitomo Durez ■) and IO parts by weight of walnut powder was supplied to a spreader roll whose temperature was adjusted to 90°C.

Next, place 51 on the soil in 2 so that the end of the end in the insertion direction is located at the end of 4 in the insertion direction, and then apply adhesive to the lower surface of 52 using the above-mentioned spreader roll. ,
5 in the same fiber direction with a shift distance of IOOTItTIL in the direction toward the take-out side from 51, and then laminated in the same fiber direction as lo
Stack up to 56 with a shift distance of oim, and immediately
After tightening at a pressure of g/cit for 6 minutes, it was opened and closed.

Place the compressed material in the soil of 2, 1400mm in the direction of the removal side.
After moving, 57 was newly placed on soil 2 with 51 butt-end to butt-end, and 58 was placed butt-to-bottom with 52 immediately after applying the adhesive on the lower surface, and stacked up to 52 in the same manner.

Immediately tighten the pressure at 10kicyyffi for 6 minutes (Figure 2 shows this state), then open it, move the object to be pressurized as described above, repeat the same operation, and tighten the endless LV.
L was produced.

Finally, cut off the stepped part at the end of the LVL that was compressed.
When manufacturing starts next time, place it on the take-out side above 2 and use it for joining to the reverse staircase part of the LVL head.

In addition, in this example, the reverse staircase part of the head of the continuous LVL of the first product was cut off because no pressure was built up, but if the pressing mold 3 is used only during the first pressing, the reverse staircase part of the head can be discarded. It is not necessary, for example, the head reverse step may be cut out and joined to the tail step, or vice versa.

A large number of test specimens containing one adhesive layer each were cut out from the LVL obtained in this example and an adhesive strength test was conducted.The test specimens cut from the staircase part had an average weight of 75 kg/c under normal conditions.
rit (wood breakage rate 75 excellent), average 70 after boiling for 72 hours
kg/cit (wood breakage rate 93%), normal average of 68kg/ail (wood breakage rate 85φ) for the parts other than the staircase part, average 65ky/cI7t (wood breakage rate Zoo%) after 72 hours of boiling, and there is no practical problem. It was in good condition with no problems.

The bending strength of the product LVL is 6.0% of the strength of the part that does not include the staircase part.The strength of the staircase part is 6.0% when measured with the adhesive layer held horizontally, and 6.0% when measured with the adhesive layer held vertically. In this case, the value was 95%.

Example 2 In Example 1, ■ The size of the dry hot veneer is thickness x length x width 5 x 7.
00X900, @ veneer temperature is 110℃, O adhesive formulation is melamine formaldehyde resin adhesive (Vigeta Lime MA-204 manufactured by Sumitomo Bakelite ■)
) 100 parts by weight, 10 parts by weight of wheat flour, and 1 part by weight of ammonium chloride.
5℃, and the veneer lamination method is 14 degrees Celsius in the direction of the veneer fibers.
In this example, each time 00ii veneer is lined up, the distance is 700m.
The normal adhesive strength and normal bending strength were as shown in Example 1 when two veneers of m were arranged side by side in the fiber direction.
obtained similar good results.

Example 3 In Example 1, ■ The mold 4 was manufactured so that the 6-step staircase part fit the scarf part of the veneer as shown in Fig. It is attached to the insertion side end of the upper clamping plate so that it can be moved by a hydraulic cylinder 7 for 40 yran or more in the insertion direction and the removal direction (veneer fiber direction).

O All of the veneers are cut into parallel scarf shapes using a 40-meter circular saw at both ends of the wood grain, and the lamination method is such that the scarf surface faces downward in the insertion direction and toward the ground in the removal direction. Example 1: When compacting, the soil pressure plate 1 was lowered, and just before 1 and 4 came into contact with the veneer, 4 was moved in the removal direction to fit 4 into the scarf of the veneer. Example 1 Similar good results were obtained, but especially in the bending test where the adhesive layer was held horizontally, the value for the stepped portion reached 70% of the value for the portion that did not include the stepped portion.

[Brief explanation of drawings]

Figure 1 shows an example of the pressing state for creating the first step-like LVL material, Figure 2 shows the pressing state in Example 1, and Figure 3 shows the example. 3 shows the clamped state in step 3. In the figure, 1 and 2 are upper and lower clamping plates, 3 and 4 are stepped and reverse stepped type, 5 is LVL material, 51 to 5, 2 are veneers, 6 is a ram for clamping and opening, pressure Showing the cylinder. 7 is oil for advancing and retracting the pressing type

Claims (1)

[Scope of Claims] 1. In a method for manufacturing LVL by laminating and pressing veneers coated with adhesive using a flat plate press, a reverse stepped mold is used on the insertion side of the flat press; The veneers coated with adhesive are stacked in a stepped manner on the lower clamping plate so that the insertion side ends of the veneers fit into the mold, and then pressed with a predetermined pressure, and the adhesive is applied. (c) When opening and closing, move the pressurized object from the insertion side of the flat plate press to the take-out side, and so that the step-like part of the press-pressed object remains on the take-out side of the flat plate press. , (d) Then, while attaching the veneers coated with adhesive to each layer of veneer in the step-like part of the object to be pressed, and carrying out the above step (a) at the same time, A continuous LVL manufacturing method characterized by repeated implementation. 2. Claim 1, wherein the veneer temperature is 60°C or higher.
A method for producing continuous LVL as described in Section 1. 3. Shifting the same length of veneer by the same distance more than 5 times the thickness,
A method for manufacturing a continuous LVL according to claim 1 or 2, in which the continuous LVL is laminated in a stepwise manner. 4. The method for manufacturing continuous I and VL according to claim 1 or 2, wherein the veneer is cut into a scarf shape in parallel at both ends on the buttside side. 5. The continuous LVL manufacturing method according to claim 4, wherein the veneers are laminated so that the angle between the horizontal surface of the lower pressing plate of the flat plate press and the scarf surface of the insertion side end of the veneer is an acute angle. 6. The adhesive 1 is a resulginol resin, a phenol resin, a melamine resin, a penzoguanamine resin, an acetoguanate resin, a urea resin, an epoxy resin, a polyurethane prepolymer, or an incyanate compound. Claims 1, 2, and 3 are thermosetting resin marine products containing one or more selected from the group of
The method for producing continuous LVL according to item 1 or 4. 7 Claims 1, 2, 3, and 4, characterized in that the method for applying adhesive to the veneer does not apply adhesive to the upper part of each stepped step. 6. The continuous LVL manufacturing method according to item 5 or 6. 8. A patent claim characterized in that the method for applying adhesive to veneers is such that adhesive is not applied to the lowest veneer during stacking, and adhesive is applied to the lower surface of all other veneers. A method for producing continuous LVL according to range 1, 2, 3, 4, 5, or 6.