JP3200688B2 - How to apply adhesive - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for applying an adhesive for shortening the time for curing the adhesive between veneers and reducing the cost of manufacturing plywood.

[0002]

2. Description of the Related Art Conventionally, when an adhesive is applied to a material to be treated, for example, a veneer, a pair of upper and lower rotating coatings which come into contact with the front and back surfaces of the veneer as described in Japanese Patent Publication No. 57-48978. A rotatable doctor roll is provided on each of the rolls such that their downward rotating sides face each other, and
The adhesive is stored between the roll and the application roll.
The thickness of the adhesive layer adhering to the peripheral surface of the application roll is adjusted by appropriately changing the interval between the rollers, and a single plate is passed between the two application rollers to allow the adhesive layer on the peripheral surface of the application roller to pass. On the front and back of the veneer,
An adhesive application device was used which was a method of bonding with a veneer sent from above and below in a separate step. In this case, the supply amount of the adhesive to the adhesive reservoir is set in consideration of the application amount to the veneer and the time interval of the supply time. And
In order to shorten the time for the adhesive between veneers to cure and reduce the cost of plywood production, the distance between the doctor roll and the coating roll is reduced, and the amount of coating on the peripheral surface of the coating roll is reduced. There is a means for reducing the amount of filler and a means for increasing the amount of a bulking agent such as flour.

[0003]

However, in order to reduce the amount of coating on a single plate for cost reduction, etc., a doctor roll and a coating roll are required.
If the amount of adhesive supplied to the adhesive reservoir does not change when the distance between the adhesive and the roll is reduced and the amount of application on the peripheral surface of the application roll is reduced, or the amount of filler such as flour is increased, the time of supply The interval becomes longer. For this reason, as time passes, the viscosity of the adhesive accumulated between the two rolls increases, so that the adhesive does not adhere to the peripheral surface of the application roll, and the application to the veneer can be performed. Disappears.

[0004] This is because the capacity of the adhesive reservoir of the conventional adhesive coating device is set by the length of the peripheral surface of the application roll that comes into contact with the adhesive and the amount of application to the veneer. When the amount of application is reduced, the time interval for supplying the adhesive to the adhesive reservoir becomes longer, and the adhesive remaining between the rotating application roll and doctor roll is constantly stirred,
This is because the water content rapidly evaporates from the liquid surface and both roll surfaces, and the viscosity of the adhesive gradually increases. Even when the amount of the bulking agent is increased, the viscosity of the adhesive is high from the beginning, so that the viscosity becomes too high with time to such an extent that the adhesive cannot be applied to the veneer.

[0005]

In order to solve the above-mentioned problems, the present invention provides a method of applying a water-soluble adhesive to an untreated material while replenishing the water-soluble adhesive with water, or forming a water-soluble adhesive around the glue spreader. It is configured such that it is covered with a non-breathable member, the covered space is provided with a moisture-absorbing material having good water absorbency, and the moisture-bearing material is applied in a wet state.

[0006]

Since the present invention is constructed as described above,
Water is supplied as appropriate to evaporation of water from the adhesive due to rotation of the doctor roll and the doctor roll, or evaporation of water can be suppressed.

[0007]

【Example】

Embodiment 1 As shown in FIG. 1, coating rolls 1 are provided on both front and back surfaces of a veneer 3 which passes through a coating roll 1 and a doctor roll 2, which are glue spreaders, from left to right in the drawing. It is provided at a position where it contacts the veneer 3. Coating roll 1 and doctor roll of equal length
This plate (not shown) is pressed against both sides so that the end faces of the screw 2 are flush with each other. A water-soluble adhesive 4, for example, a urea resin adhesive, is poured from a nozzle (not shown) and stored between the two rolls, and each roll is rotated in the direction of the arrow.

To supply water, a nozzle 5 for blowing water vapor is disposed opposite to the adhesive 4 of each of the application roll 1 and the doctor roll 2. When the adhesive 4 is applied to a veneer having a large width in the direction perpendicular to the veneer advancing direction, the lengths of the application roll 1 and the doctor roll 2 naturally become longer. Then, the number of nozzles 5 may be increased. The amount of water vapor blown out from the nozzle 5 is determined by providing a throttle valve 6 in the pipe leading to the nozzle 5 and checking the viscosity of the adhesive 4 between the coating roll 1 and the doctor roll 2 as appropriate. The throttle valve 6 is adjusted. For example, in the case of a urea resin adhesive, the viscosity of the adhesive is usually used at 10 to 40 poise. To measure the viscosity, an operator touches it with his / her hand or confirms it visually. By doing so, when the viscosity of the adhesive 4 is likely to be high, by supplying water, it is possible to maintain an appropriate amount of water, and the viscosity of the adhesive 4 becomes too high to apply. Is eliminated.

A method for measuring the viscosity of the adhesive 4 is as follows.
In the adhesive 4 between the two rolls, a shaft 9 having a blade 7 at the tip end as shown in a partially enlarged view in FIG. 2 and the other end connected to a speedometer generator 8 is rotated at a constant torque. Using the device, the value of the electromotive force obtained from the generator 8 is digitally displayed, and the operator adjusts the throttle valve 6 according to the displayed value. Or
The value of the electromotive force obtained from the generator 8 is compared with a reference value,
It is configured to automatically control the amount of water vapor according to the result, for example, by comparing the electromotive force obtained when the adhesive having a viscosity of about 20 poise is similarly rotated with a reference value, As the water evaporates and the viscosity decreases, the electromotive force becomes 2
When the ratio becomes lower, the valve of the nozzle 5 is opened to supply steam, and when the value of the electromotive force obtained from the generator 8 becomes higher than the reference value by 20%, the valve of the nozzle 5 is closed. To automatically stop the supply of water vapor.

On the other hand, in the above-described embodiment, the nozzle may be changed to the nozzle 5 for blowing water vapor instead of the nozzle 5 for blowing water vapor. In this case, the amount of water dropped from the nozzle is adjusted in the same manner as described above. The position for supplying the water is not limited, and the bonding is performed by supplying the water to the roll surfaces of the application roll 1 and the doctor roll 2 after leaving the adhesive 4. The agent 4 may be replenished with water indirectly.

Embodiment 2 FIG. 3 does not actively replenish moisture as in Embodiment 1 described above. The coating roll 1 and the doctor roll are not provided except for the entrance and exit of the veneer 3. The entirety of the non-breathable member 10
The adhesive chamber 11 is provided so as to cover the inside of the adhesive chamber 11, and a humectant material having good water absorption, for example, a felt 12 is provided inside the adhesive chamber 11, and the felt 12 is applied in a state of being hydrated.
In this manner, the moisture around the coating roll 1 and the doctor roll 2 increases due to the moisture evaporated from the felt 12, and the moisture from the adhesive 4 hardly evaporates. Viscosity does not increase. When the felt 12 is used in this manner, the entrance and exit of the veneer 3 are open,
Although the surroundings of the application roll 1 and the doctor roll 2 are not completely sealed, moisture is supplied at least to the vicinity of the adhesive reservoir by the felt 12, and the humidity in the adhesive chamber 11 is reduced. Is well maintained.

[0012]

As described above, according to the present invention, it is possible to keep the viscosity of the adhesive almost as initially obtained and to apply the adhesive thinly to the veneer in a good condition. Therefore, the time required for the adhesive between the veneers to harden can be shortened, and the plywood manufacturing cost can be reduced. Further, the interval of the supply time to the adhesive reservoir becomes longer than in the case of using the conventional adhesive application device, which reduces the labor of the operator and promotes automation of the adhesive application device.

[Brief description of the drawings]

FIG. 1 is a central sectional view of an adhesive application device according to a first embodiment of the present invention.

FIG. 2 is an explanatory diagram of an apparatus for measuring the viscosity of an adhesive.

FIG. 3 is a central sectional view of an adhesive application device according to a second embodiment of the present invention.

[Explanation of symbols]

1. Application roll, 2. Doctor roll, 3. Single plate, 4. Adhesive, 5. Nozzle, 6. Throttle valve, 7.
· Blades, 8 · · · generator for speedometer, 9 · · · shaft, 10 · · · non-breathable members, 11 · · adhesive chamber, 12 · felt.

Claims (4)

(57) [Claims] When applying a water-soluble adhesive to a material to be processed by a glue spreader, water is supplied to the water-soluble adhesive between the doctor roll and the application roll of the glue spreader. Method of applying adhesive while applying. 2. The coating method according to claim 1, wherein water is supplied by spraying steam onto the adhesive. 3. The coating method according to claim 1, wherein the water is replenished by dropping the water. 4. When the water-soluble adhesive is applied to a material to be processed by a glue spreader, the space around the doctor roll and the application roll of the glue spreader is covered with a non-breathable member. A method for applying an adhesive, comprising: applying a moisturizing material having good water absorbency to the material;