JPH0354042B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to an apparatus for supplying adhesive to veneer veneers, which is applied to a novel plywood manufacturing method in which veneer veneers with high moisture content are bonded together.

[Background of the Invention] In the conventional plywood manufacturing process, in the bonding technology of veneer veneers (hereinafter simply referred to as veneers), the main cause of bonding failures such as punctures or insufficient adhesive strength is excess adhesive. It is well known that the veneer has a high moisture content, which inhibits the absorption of moisture contained therein.

However, it is virtually impossible to properly equalize the moisture content of all veneers through drying, and the reality is that there are various uneven moisture contents, especially in recent years due to the situation of logs. Deterioration of veneer leads to a mix of wood species that are difficult to dry and those that are easy to dry, leading to either poor adhesion due to insufficient drying, or excessive veneer shrinkage or waviness due to overdrying. The current situation is that

Therefore, in order to respond to the current situation and the potential for such problems, it is desired to establish an adhesive technology that is not or is not easily affected by uneven moisture content of the veneer.
In order to save energy, streamline the drying process, and improve the yield of veneers, there was a strong desire to establish adhesive technology for veneers with high moisture content.

[Prior art] By the way, such adhesion has been conventionally described, for example, in "Method for manufacturing plywood" (Japanese Patent Publication No. 54-3929).
According to the publication, a known plywood adhesive is applied to a veneer, dried until gelatinization occurs, and other veneers are stacked and heat-pressed. It is said that this is sufficient, and reasonably good test examples have been shown.

[Problems to be Solved by the Invention] However, in addition to the drawback that the above-mentioned prior art requires a large drying device of the same type as that used for drying veneers, in each test example of the above-mentioned publication, As is clear from the fact that the higher the drying rate, the greater the drying conditions, the following disadvantages were inherent.

That is, in the conventional technique, when drying the adhesive applied to the veneer, if the drying conditions are kept constant, if the moisture content of the veneer is low, only the adhesive will be dried, resulting in over-drying. On the other hand, if the moisture content of the veneer is high, the veneer will also be dried, resulting in insufficient drying of the adhesive, making it impossible to dry only the adhesive uniformly.

Therefore, in order to dry the adhesive to the desired state, it is necessary to variously change the drying conditions of the drying device depending on the moisture content of the veneer. It is virtually impossible to accurately change the drying conditions for a board or a large number of veneers with different moisture contents, as it is to dry all veneers uniformly. In the end, the above-mentioned conventional technology was not suitable for manufacturing plywood aimed at mass production.

[Means for Solving the Problems] The present invention was developed on the premise that it can be applied to a new plywood manufacturing method that solves the above-mentioned difficulties. A coating device is provided for coating a plywood adhesive in a thin film onto the transfer surface of the transfer device to be transferred, and a thin film is applied on the transfer surface at a position downstream in the transfer direction from the position where the adhesive is applied by the coating device. a drying device for reducing the moisture content of the adhesive; further, if necessary, a peeling device is provided at a lower position of the drying device to set a peeling position for peeling the dried thin film adhesive from the transfer surface; We propose an adhesive supply device for a veneer, characterized in that a veneer conveying device is provided at a position where the thin film adhesive peeled off at the peeling position is to be supplied to the bonding surface of the veneer.

[Function] According to the device configured as described above, the adhesive coated in a thin film on the transfer surface of the transfer device has its moisture content reduced by the drying device, and is further peeled off at the peeling position before being transported. It will be supplied to the adhesive surface of the veneer transported by the device, but since the moisture content of the thin film of adhesive is reduced before being supplied to the adhesive surface of the veneer, the drying device is extremely A small device is sufficient, and unlike the prior art described above, only the adhesive can be dried stably as desired under predetermined drying conditions without being affected by the moisture content of the veneer. Adhesives that have been dried in a similar manner enable bonding that is less affected by uneven moisture content in the veneers, and can significantly reduce or almost eliminate the absorption of excess moisture into the veneers. Naturally, it is also possible to bond veneers with high heat resistance.

[Example] Hereinafter, the present invention will be described in further detail with an example of implementation illustrated in the drawings.

FIG. 1 is an explanatory side view of an embodiment of an adhesive supply device according to the present invention.

In the figure, reference numeral 5 denotes a coating roll that applies adhesive 4 in a thin film to the outer peripheral surface of a cooling roll 6 rotating in the direction of the arrow in the figure.

7 is a heating roll that heats the adhesive 4 transferred from the outer peripheral surface of the cooling roll 6 to appropriately reduce the moisture content of the adhesive 4.

Reference numeral 8 denotes a peeling knife that facilitates peeling off the thin film adhesive 4' from the outer peripheral surface of the heating roll 7.

Reference numeral 9 denotes a pressure roll that applies pressure to the top plate 2, middle plate 1, and back plate 3 which are overlapped with each other via the thin film adhesive 4' to temporarily bond them together.

Reference numeral 10 denotes a conveyor that guides and conveys the top plate 2 and the back plate 3 to the position of the pressure roll 9.

The adhesive supply device according to the present invention is configured, for example, as described above, and initially, the tip of the thin film adhesive 4' that is peeled off from the heating roll 7 via the peeling knife 8 is manually removed. Therefore, after being guided and transferred to the adhesive surfaces of the top plate 2 and the back plate 3 by appropriate automatic means, the middle plate 1 and the top plate 2 are
If each of the back plates 3 is continuously conveyed as shown in the figure, a thin film of adhesive 4' continues between the front plate 2 and the middle plate 1, and between the middle plate 1 and the back plate 3. supplied.

After that, the veneers that have been temporarily bonded using pressure rolls are either heat-pressed in the usual manner (after cold-pressing if necessary), or the adhesive is applied while they are cold-pressed. Let it harden and perform the main adhesion. Incidentally, an example of drying an adhesive using the above-mentioned apparatus is given below, where "parts" refer to parts by weight.

Experimental Example: Composition of Adhesive 4; The base glue was 100 parts of melamine urea co-condensed resin adhesive (S-Resin manufactured by Shoei Chemical Co., Ltd., product number SA-30, containing about 54% non-volatile resin component), 20 parts of wheat flour,
4 parts of water, 1 part of ammonium chloride, temperature of cooling roll 6: 15°C, amount of adhesive applied by coating roll 5 to cooling roll 6: 15 g/square, outer circumference of cooling roll 6 and heating roll 7 Ratio of transfer speed on the surface: 1:1, temperature of heating roll 7: 90°C, time for the adhesive coated in a thin film to substantially stay on heating roll 7: 18 seconds,
Ratio between the transfer speed on the outer peripheral surface of the heating roll 7 and the supply speed of the thin film adhesive 4' to the veneer; 1
Vs 1.

Under the above conditions, the thin film adhesive 4' that is dried and peeled off by the peeling knife 8 is obtained as a continuous soft thin film.
It was possible to continuously supply between each veneer.

Incidentally, the weight of the thin film adhesive 4' is approximately 100, assuming that the weight of the adhesive 4 before drying is 125, and furthermore,
The absolute dry weight (weight of non-volatile components) was measured and was approximately 75.

Therefore, in connection with the above-mentioned experimental example, an adhesion test was conducted on 3-ply plywood manufactured by supplying the thin film adhesive 4' between each veneer as described above, but the results were not as follows. It is as follows.

In other words, front and back plates with a moisture content of 10% and a thickness of 1.7 mm (however,
The moisture content of the veneer in the present invention is expressed as a known dry moisture content) and a medium plate with a thickness of 3.6 mm and a moisture content of 0 to 120%, and was heated at 115°C for 3 minutes. When we determined the adhesive strength of Class 1 plywood manufactured by heat pressing using the repeated boiling test method specified by JAS, we found that:
High adhesion was shown when the moisture content was generally 30 to 50%.
However, even when an intermediate plate with a water content outside the specified range was used, the adhesion was quite good.

Furthermore, by changing the conditions in the above experimental examples, the degree of dryness of the thin film adhesive is increased to a level higher than that of the above experimental example, and plywood is produced by obtaining a dryer thin film adhesive, When conducting the adhesive force test, it was found that when a medium plate with a higher moisture content than the above mentioned range was used, higher adhesive force was obtained, and conversely, the degree of dryness of the adhesive was lowered to less than the above example. When carrying out this test, higher adhesion strength tended to be obtained when an intermediate plate with a moisture content lower than the above mentioned range was used.

However, the lower the degree of dryness of the adhesive, the more difficult it is to peel it off, and the more likely it is that it will stick to a peeling knife, etc., so if you are aiming for such implementation,
The following embodiments are advantageous.

That is, in the embodiment illustrated in FIGS. 5 and 6, the peeling knife in the embodiment shown in FIG.
The top plate 2 and the back plate 3 are brought into contact with the heating roll 7, and the thin film adhesive 4' is transferred directly from the heating roll 7 to the adhesive surfaces of the top plate 2 and the back plate 3. This is advantageous because it can be carried out without any particular difficulty even if the degree of dryness of the adhesive is low.

On the other hand, if the degree of dryness of the adhesive is increased beyond the limit, the thin film of adhesive is likely to be crushed by the peeling knife, and the supply to the adhesive surface of the veneer will become unstable, so excessive drying is not recommended. Although it is desirable to avoid this as much as possible, if such implementation is desired as necessary, it is recommended to provide a dispersion device that can disperse the broken adhesive as evenly as possible on the adhesive surface of the veneer. Desirably, and if necessary, it is effective to provide a pulverizer for actively pulverizing the adhesive into fine particles.

Examples of the device according to the present invention and some of the experimental results using the device have been described above.
Furthermore, the characteristics of the individual members constituting the device, the characteristics of adhesives and veneers suitable for use, and the usage characteristics of the device will be described in detail.

First, to explain in detail the members constituting the apparatus of each of the embodiments, the cooling roll and heating roll are:
It also serves as a transport device for transporting a thin film of plywood adhesive. That is, from the coating position where the coating roll applies the adhesive to the outer circumferential surface of the cooling roll to the peeling position with the peeling knife on the outer circumferential surface of the heating roll, a substantially thin film of plywood adhesive is formed. It forms the transfer surface of the transfer device that transfers the agent. Moreover, since the heating roll also serves as a drying position, it is necessary to prevent coating failure caused by heat transfer from the heating roll to the adhesive before coating, so the cooling roll is not used. The cooling roll maintains the adhesive before coating at a low temperature to stabilize coating at the coating position by the coating roll, and also prevents the applied adhesive from being transferred to the heating roll. It facilitates the transition.

Therefore, if there is no risk of coating failure occurring at the coating position, such as when setting the temperature of the heating roll to a low temperature, the cooling means such as the cooling roll is not necessary, and for example, when the coating position is A coating device such as a roll may be installed directly on the transfer surface of a transfer device that also serves as a drying device, and in such a case, the drying device covers the entire area from the coating position to the peeling position. , a thin film of adhesive will be dried, but in any case, the transfer device and the drying device do not necessarily have to be used together, and depending on the specific aspects of both devices, including the example described below. There is no problem in preparing for each separately.

In addition to the combination of a cooling roll and a heating roll in each of the illustrated embodiments, there are also other transfer devices, such as a combination of an endless belt and an endless belt, or a combination of an endless belt and a roll. When divided into two or more members in the transfer direction to form a series of transfer surfaces, the relative transfer speed of each member's transfer surface may be adjusted as necessary. This adjustment allows the thickness of the adhesive film on the transfer surface to be adjusted during transfer. Incidentally, in the above experimental example, the ratio of the transfer speeds on the outer peripheral surfaces of the cooling roll and the heating roll was set to 1:1, but it could be set to an arbitrary ratio such as 1:2 or 2:1. The ratio can be set to

Furthermore, the transfer surface of the transfer device is closely related to the manner in which the adhesive is applied by the coating device,
This is a factor that determines the specific form of the thin film adhesive, such as 0.03mm, 0.07mm, 0.1mm, 0.15mm, 0.2mm.
etc., in addition to transferring ordinary thin film adhesives of various thicknesses that are uniform throughout, if necessary, for example, in a direction perpendicular to the supply direction or in the same direction as the supply direction. Thin film adhesive with uneven thickness, or thin film adhesive consisting of a group of narrow strips of adhesive separated into multiple strips along the supply direction, or even multiple strips along the supply direction. Since there are cases where a thin film adhesive made of a group of separated fine line adhesives or the like is intentionally deformed in an unusual manner, it is not necessarily necessary to form it flat. Incidentally, the outer periphery of the cooling roll in each of the illustrated apparatuses is coated with rubber in the same manner as the coating roll of a general coating apparatus, and thread-shaped narrow grooves are formed on the outer periphery, and the heating roll is This was carried out by applying hard chrome plating to the flat outer circumferential surface of the heating roll, but there was no particular problem in practical use, and similarly there was no problem when desired irregularities were formed on the outer circumferential surface of the heating roll.

In addition, the coating roll should preferably be cooled if necessary to stabilize coating, and should also be constructed so that it can be moved relative to the transfer surface of the transfer device to increase or decrease the amount of coating. For example, it is convenient when performing accelerated peeling, which will be described later.
The rotation speed etc. can be set according to general coating equipment, but in any case, the coating equipment is not limited to coating rolls, but in short, it is necessary to apply, cast, or spray adhesive to form a thin film. Various conventionally known methods such as a blade coater and spray can be used as long as they can be applied in a uniform manner.

Regarding the drying device, as mentioned above, in each of the illustrated embodiments, the main body is a heating roll. However, if necessary, it is also possible to adopt a double-sided heating type drying device, or even an internal heating method using a microwave drying device, etc., or use other well-known heat radiation type Including convection type and heat conduction type drying equipment,
Although all of them are based on drying by heating, the device according to the present invention is a blower type dryer, a vacuum dryer, etc., which is basically drying at normal temperature (room temperature) without heating. can also be adopted depending on the actual situation.

The location of the drying device is not particularly limited as long as the applied adhesive can be dried as desired in any area between the coating position and the peeling position on the transfer surface of the transfer member. However, if necessary, as described below, an auxiliary drying device may also be provided in the area after the peeling position where the adhesive would normally dry naturally.

Furthermore, the drying conditions of the drying equipment must be set to match the moisture content of the veneer used.
Normally, according to the regular control method, a moisture content meter is installed near the veneer conveyance path to detect the moisture content of the veneer being carried in in advance, and the drying conditions of the drying device are set based on the detected value. Since the normal settings may not always be able to adequately handle the situation, it is desirable to use the following auxiliary adjustment means as necessary.

That is, as illustrated in FIG. 2, for example, a moisture content meter 11 is provided near the peeling position of the thin film adhesive 4' to detect the moisture content of the peeled adhesive 4' and to detect the moisture content of the peeled adhesive 4'. The detected value of the moisture content of the top plate 2 detected in advance by a moisture content meter (not shown) provided near the route is compared with the detected value, and the percentage of moisture contained in the peeled adhesive 4' is determined. If the water content does not match the moisture content of the top plate 2 and is lower than the desired ratio, for example, as shown in FIG. ,
If a humidifying device 12 such as a sprayer is provided at an appropriate position before the peeling position and the thin film adhesive 4' is humidified, the percentage of water contained in the adhesive 4' can be reduced by
can be adapted to the moisture content of the top plate 2, on the other hand,
If the percentage of moisture contained in the thin film adhesive 4' is higher than the desired percentage, an auxiliary drying device (not shown) provided in the area after the peeling position may be used as needed. It is sufficient to perform proper drying.

In addition, when carrying out the above-mentioned humidification, if a humidifying device is provided on both sides of the thin film adhesive, as illustrated in FIG. It is very convenient because it allows you to adjust the humidity, and furthermore, the humidifying substance used for humidification can be, for example, water,
Examples of humidifying substances include hot water, steam, formalin, various types of water-soluble adhesives, and acidic aqueous solutions such as diluted hydrochloric acid and ammonium chloride. In addition to spraying, there are various other methods such as spraying, coating, and scattering, but in any case, such humidification is simply an effect of adjusting the moisture content of the thin film adhesive to the moisture content of the veneer. In addition, it also has the effect of improving the adhesion, so if necessary, humidification may be carried out with the main purpose of improving the adhesion.

In other words, thin film adhesives with low moisture content tend to lack permeability (wetting, adhesion) to veneers, and this tendency is particularly marked for veneers with low moisture content. Humidification restores permeability,
It is extremely effective in improving its adhesion,
For example, the plywood used in the adhesion test mentioned above had a low moisture content for the front and back plates, so there were few wood chips at the bonding surface, and most of them were between the veneer and the adhesive. However, based on the configuration shown in Figure 3 above, both sides of the thin film adhesive were humidified by steam injection, with the aim of adding approximately 0.8 g of water per square meter of one side, and the same process was repeated. Produce plywood under the conditions,
An adhesion test showed that the adhesion was significantly improved. Incidentally, as will be explained later, if you conversely humidify the bonding surface of a veneer with a low moisture content, or if necessary, even if you humidify the bonding surface of a veneer with a moderately high moisture content, the result will be approximately the same. Adhesion is improved, but
In any case, excessive humidification is inappropriate, and when applying humidification that mainly consists of water, the total amount of water must be
Preferably, the amount is kept at about 5 g or less per square meter on one side, more preferably about 3.5 to 0.3 g.

In addition, the peeling device may be provided at the peeling position if necessary, and in addition to the peeling knife shown in the figure, a contactless peeling device such as a known air knife can also be employed, but in any case, The peeling position by the peeling device does not necessarily need to be fixedly set, but if it is configured to be movable relative to the transfer surface of the transfer device and the peeling position can be changed, the peeling position can be changed by changing the peeling position. This is convenient because the degree of dryness of the adhesive can be adjusted, and the tip of the peeling knife shown in the figure can be moved back and forth between the peeling position and the bonded surface of the veneer, so that it is possible to adjust the degree of dryness of the adhesive. If the leading edge of the adhesive is guided and transferred to the bonding surface of the veneer, it will be extremely easy to start supplying the adhesive, which is extremely effective in practice.

Regarding the veneer conveyance apparatus, in each of the illustrated embodiments, the intermediate plate is conveyed linearly, the top plate and the back plate are bent, and the veneer is conveyed continuously or intermittently.
In addition, the peeled thin film of adhesive lightly contacts one of the bonding surfaces of the two veneers to be bonded first, then the other after a very short time or a very short distance. In addition to this, for example, a conveyance mode configured such that either one of the adhesive surfaces is lightly contacted first, and then the other adhesive surface is lightly contacted after a considerably long time or a considerably long distance;
Alternatively, the conveyance mode is structured so that it makes light contact with both adhesive surfaces almost simultaneously, and furthermore, it extends in the vicinity of both adhesive surfaces for a considerable distance without contacting either of the adhesive surfaces (However, this state is already In other words, the adhesive is in a state equivalent to being supplied to the adhesive surface), and the conveyance mode is such that the adhesive is brought into light contact with the adhesive surface of any appropriate size at the appropriate time and at the same time. As long as it has the function of conveying the veneer to the position where the adhesive is to be supplied to the bonding surface of the veneer, it can be employed without any particular restrictions on its conveyance route, conveyance direction, conveyance posture, etc.

It should be noted that the pressure roll in the apparatus shown in Fig. 1 can also be installed in the position shown in the figure, if necessary. Temporary adhesion can be performed separately in the process after the device, so in principle, the device itself only needs to simply supply the peeled adhesive to the bonding surface of the veneer. However, if provided, it is preferable that the outer periphery be covered with an elastic material, and if necessary, an appropriate number of grooves connected in the circumferential direction may be formed so that a conveying member such as a needle belt can pass through. It is also possible to stabilize the conveyance of the veneer by structuring the veneer, or to maintain it at an appropriate high temperature by heating it by appropriate means.

Next, regarding the adhesive to be used, in the device according to the present invention, known adhesives mainly made of urea resin, melamine resin, phenolic resin, water-based vinyl urethane resin, or co-condensed resins or mixed resins thereof, etc. Water-soluble plywood adhesive is used, but
Generally, these adhesives are commercially available as aqueous solutions containing 40 to 55% water (however, in the present invention, the percentage of water contained in adhesives is expressed as a weight ratio to the total weight). Therefore, we use these as a base glue, and if necessary, add common extenders and hardeners such as water, flour, and ammonium chloride, as well as additives such as plasticizers and fillers.
It is mixed into a commonly used standard formulation or a known special formulation and supplied to the equipment.

At that time, although it depends on the type of base glue, it is desirable that the proportion of water contained in the prepared adhesive be as low as possible in view of ease of drying, etc.
~70% is a desirable guideline, and drying conditions are set so that the moisture content is reduced to approximately 15 to 35% (preferably 18 to 35%) using the apparatus according to the present invention. do. Incidentally, in the case of the above experimental example, the water content was reduced from 40% at the time of preparation to about 25%.

Furthermore, if the adhesive is dried under heated conditions as in the illustrated embodiments, the condensation reaction of the base glue will be accelerated and the condensation will proceed excessively, causing the adhesive to dry before reaching the desired drying range. There is a risk that the adhesive performance and ductility of the agent will deteriorate, so the temperature condition was set to 110℃.
It is preferable to set it below, but on the other hand, 100
Drying at high temperatures above ℃ has the advantage of significantly promoting the reduction of water content, so if necessary, drying at high temperatures can be carried out while suppressing the progress of the condensation reaction. For example, the pH of the adhesive can be adjusted from weakly acidic to (neutral) to alkaline by adding a small amount or zero of a hardening agent such as ammonium chloride, or by adding hexamethylenetetramine, etc. After that, dry at high temperature.

Of course, the above-mentioned adjustment of the PH of the adhesive after drying can be applied even when drying is carried out at a low temperature of 40 to 100°C or at room temperature without heating at all. In that case, when supplying the dried thin film adhesive to the veneer, add ammonium chloride, etc. to the adhesive or the bonding surface of the veneer to readjust the pH and heat the adhesive. It is desirable to improve the adhesive curing conditions during compaction or cold compaction, and if necessary, consider the progress of the condensation reaction during the drying process under such arbitrary temperature conditions. The degree of condensation of the base glue used may be lowered in advance, or the progress of the condensation reaction may be delayed.
If it does not affect adhesive performance, ductility, etc.,
Conversely, the degree of condensation of the base glue used may be increased in advance.

In addition, if the ductility of the thin film adhesive is high, it will be easier to supply it to the veneer, and it will also improve the adhesion (compatibility) with the veneer, which is beneficial.
In order to maintain greater ductility, it is preferable to add a known plasticizer to the base glue used. For example, in the case of an amino resin adhesive, a plasticizer such as tricresyl phosphate or cresyl diphenyl phosphate is added. It is appropriate to add an appropriate amount of plasticizer, and since this type of plasticizer usually also has the function of a lubricant, it somewhat improves the peelability of thin film adhesives. The factor that greatly affects the ductility of adhesives is its degree of dryness.
Thin film adhesives with a relatively high moisture content after drying tend to have relatively high ductility, while those with a low moisture content tend to have low ductility. Incidentally,
When the experiment was carried out by changing the term in the above experimental example to 30g/square meter, the term to 37 seconds, and the term to 1:3, 1:2, and 1:1.5, the results showed that the thin film after drying The moisture content of each adhesive was approximately 32%, but the adhesives were softer and more ductile than those in the previous experimental examples.

In addition, among the changes in the above conditions, the ratio of the transfer speed on the outer peripheral surface of the heating roll and the supply speed of the thin film adhesive to the veneer was changed to 1:1.
By changing the ratios from
However, if such accelerated peeling is actively employed, the thickness of the adhesive supplied can be arbitrarily adjusted to suit the conditions of the veneer to be bonded. This is convenient because the technology can be established;
For example, in the apparatus shown in Fig. 1, it is sufficient to configure the conveyance speed of the conveyor and the pressure roll to be variable (increased), and conversely, to configure the transfer speed of the heating roll to be variable (deceleration). However, in this case, it is necessary to be careful that the drying conditions will also change.

In addition, since the accelerated peeling method facilitates the peeling of the thin film of adhesive from the heating roll in front of the peeling knife, it is also possible to omit the installation of the peeling knife, and in this case, the peeling position is determined mainly based on the relationship between the transfer speed and the supply speed, but in any case, when such accelerated peeling is performed, a phenomenon similar to a diffusion phenomenon occurs in the soft adhesive immediately after peeling. It was confirmed that the thickness unevenness of the adhesive immediately before peeling was diffused, and as a result, the thickness of the peeled adhesive tended to become more even. This is consistent with the basic principle.

Next, regarding the properties of the veneer, it is most convenient to form the veneer into a continuous band shape with the fibers aligned in a predetermined direction. Even if the materials are cut into a rectangular shape, they can be used without any particular problem if they are transported closely spaced or close to each other.

Furthermore, as is clear from the results of the adhesive force test described above, adhesives whose moisture content is reduced as described above using the apparatus according to the present invention, etc., generally have a relatively low moisture content. It exhibits high adhesive strength when bonding veneers with a high moisture content, and conversely, the higher the moisture content, the higher the adhesive force when bonding veneers with a lower moisture content. However, in any case, in order to consistently obtain the desired high adhesive strength, it is desirable to dry the veneer properly in advance. In addition to a drying method in which the entire veneer is dried as uniformly as possible, a drying method in which the adhesive surface of the veneer is mainly dried locally can also be adopted.

That is, for example, when using a veneer whose moisture content is too high, a known heating device for drying veneer consisting of a heating plate, a heating roll, etc. is installed in conjunction with the device according to the present invention, and the heating device The device according to the present invention mainly dries the adhesive surface locally by heating and drying for a short time, and during a period when there is a real difference in moisture content between the adhesive surface and the inside, the device according to the present invention
Apply adhesive to the adhesive surface, preferably as soon as possible, as usual (if necessary, after cold pressing)
The adhesive can be cured by hot pressing or cold pressing, and it is not necessarily necessary to dry the entire veneer as before.

Furthermore, if the veneer drying process and bonding process are short-circuited in this way, the veneer may be bonded with a certain amount of heat, but this amount of heat is Since this has the secondary effect of accelerating the hardening of the adhesive during pressing, if necessary, a heating device for the veneer may be provided with the main purpose of retaining heat.

On the other hand, when using a veneer whose moisture content is too low, it is sufficient to simply use the humidifying device, humidifying substance, humidifying means, etc. similar to the example described in the explanation of humidifying the adhesive above, and use them as necessary. However, considering the degree of improvement in adhesion due to the immediate effect of humidification, as long as the moisture content of the veneer does not exceed the limit that makes it impossible to bond, as mentioned above, It is preferable to humidify the adhesive in accordance with the moisture content of the veneer.

Next, we have explained how to use each of the illustrated embodiments by giving an example of use in manufacturing 3-ply plywood. 3, or carried out the actual adhesion
If ply plywood is brought in again in place of the middle board shown in the figure, it is possible to manufacture 5-ply plywood, or if two ply veneers are brought in in place of the middle board shown in the figure, two sets of 2 It is also possible to manufacture ply plywood, and if necessary, by providing multiple units of appropriate members such as pressure rolls as common members, the required number of sheets to be bonded can be increased. It can also be used as a composite device that performs a plurality of bonding processes on any number of sets of plates, either substantially simultaneously or in series at some time or distance.

[Effects of the Invention] However, the device according to the present invention is intended for bonding two veneers, regardless of the fiber direction of each veneer, and is not easily affected by uneven moisture content. Moreover, it is possible to properly bond even materials with high moisture content, which were difficult to bond in the past, and furthermore, it is economically superior because it requires a smaller drying device than the previous technique. This device has extremely high practicality as a device that can be applied to a new plywood manufacturing method that solves the problems of .

Furthermore, when carrying out the novel plywood manufacturing method using the apparatus according to the present invention, it is no longer necessary to maintain the moisture content of the veneer as relatively low and as uniform as possible as in the past. The device according to the present invention can be expected to have ripple effects, such as being able to streamline and save energy in the veneer drying process, as well as suppressing excessive veneer shrinkage and waving caused by over-drying. In addition to veneer, for example, sawn board, plywood,
A laminate made of a single type or a combination of multiple types of sheets or plates made of any material, such as wood boards, paper, plastic, etc., using a water-soluble adhesive. Even when manufacturing
It can be provided as a useful device that can contribute to shortening, energy saving, and rationalization of the bonding process.

[Brief explanation of drawings]

The drawings are for explaining the present invention, and FIG. 1 is an explanatory side view of an embodiment of the adhesive supply device according to the present invention, and FIGS. 2 and 3 are diagrams showing the adhesive supply device according to the present invention. A partial side view of an example of local modification of
FIGS. 4 and 5 are side views of other embodiments of the adhesive supply device according to the present invention. 1...middle board, 2...front board, 3...back board, 4...
Adhesive, 4'... Thin film adhesive, 5... Coating roll, 6... Cooling roll, 7... Heating roll, 8
... Peeling knife, 9 ... Pressure roll, 9' ... Pressure roll, 11 ... Moisture content meter, 12 ... Humidification device.

Claims (1)

[Claims] 1. A coating device that applies a thin film of plywood adhesive to a transfer surface of a transfer device that moves a thin film of plywood adhesive, and a coating device that applies a thin film of plywood adhesive to the transfer surface from the adhesive coating position by the coating device. A drying device for reducing the moisture content of the thin film adhesive is provided at a lower position in the transport direction, and a peeling device is further provided as needed at the lower position to remove the dried thin film adhesive from the transport surface. A veneer veneer conveying device is provided at a position where a veneer veneer conveying device is set at a position where a veneer veneer is to be peeled off, and a thin film of adhesive peeled off at the veneer position is supplied to the adhesive surface of the veneer veneer. Adhesive supply device for plywood veneer.