JPS621803B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method of applying an adhesive to the upper surface or upper and lower surfaces of a plywood veneer during the production of plywood or a veneer laminate.

When applying the required amount of adhesive to the upper or upper and lower surfaces of the veneer veneer, the adhesive is usually placed on the side of the upper and lower application rolls 1 and 2, as shown in FIG. A plywood roll spreader 6 is mainly used, which is composed of upper and lower doctor rolls 4 and 5 that can move forward and backward to appropriately regulate the amount of adhesive applied.

Conventionally, in order to apply a desired adhesive to the upper and lower surfaces of the veneer veneer 3 using the roll spreader 6 for plywood of the above-mentioned model, the upper and lower doctor rolls 4 and 5 are moved forward relative to the upper and lower coating rolls 1 and 2 to appropriately squeeze the adhesive. After setting the amount, apply Heveneer veneer 3 between the upper and lower coating rolls 1 and 2.
A uniform coating of adhesive is transferred.

However, when creating three-layer plywood, for example, a veneer veneer 3 to which a uniform adhesive coating has been transferred is used as a core material, and a top plate 7 and a back plate 8 with their fiber directions perpendicular to each other are stacked together. However, when making the plywood, the four peripheral edges lacked adhesive holding power compared to the center, so of the four peripheral edges of the plywood, especially the front and back plates 7 and 8. There is a risk of peeling from the front and rear edges in the fiber direction, that is, from both sides in the longitudinal direction of the plywood, which poses a problem in handling and, in turn, causes a decrease in product value.

Furthermore, when obtaining a longer plywood from the plywood made by the method described above, the end surfaces of the plywood that are normally to be joined are cut into a scarf shape that has excellent joining strength, and adhesive is applied to the processed end surfaces. At this time, the processed end surface is scarf-shaped and the tip is sharpened (see Figure 2), so the core material, veneer veneer 3, and The space between the front plate 7 or the back plate 8 is particularly susceptible to peeling, which poses a problem in handling.
This has become a bottleneck during bonding.

In view of the above-mentioned circumstances, the present invention has been developed to transfer a large amount of adhesive to areas that have particularly strong adhesion holding power compared to other areas when making plywood or veneer laminates, or when processing the joint end faces thereof. A roll spreader with an arbitrary width can be applied at a fixed position on the longitudinal circumferential surface of the coating roll.
This invention provides a method for forming grooves of arbitrary depth and applying adhesive to a veneer veneer, and one embodiment thereof will be described below with reference to the accompanying drawings.

In the plywood roll spreader 6 described above and shown in FIG. 1, grooves 9 of arbitrary width and arbitrary depth are formed on the circumferential surface of the upper and lower coating rolls 1 and 2 at a plurality of locations at arbitrary intervals in the longitudinal direction. , 9' are formed.

In forming these grooves 9, 9', a plywood veneer 3 fed between the upper and lower application rolls 1, 2 is used.
However, the fiber direction is perpendicular to the longitudinal direction of the roll. First, when making plywood, the adhesive holding force described above is applied to both sides of the veneer veneer 3 in the fiber direction, which are both sides in the width direction. As it increases,
Since it is necessary to transfer more adhesive than other surfaces, grooves 9 and 9' are formed near both ends of the upper and lower applicator rolls 1 and 2.

Next, after making the plywood, if the position to be cut into the scarf shape is set at approximately the center of the veneer veneer 3, in order to increase the adhesion holding force at this center compared to other surfaces, as described above, Grooves 9 and 9' are formed approximately in the center of the upper and lower application rolls 1 and 2 as shown in FIG. (See Figure 3) Upper and lower applicator rolls 1 and 2 with grooves 9 and 9' formed thereon.
The experimental results of applying adhesive to the upper and lower surfaces of the veneer veneer 3 are as follows.

The width of grooves 9 and 9' should be 50 to 100 mm, and the depth should be approximately 5/5 mm.
100 mm and feed the veneer veneer 3 between the upper and lower application rolls 1 and 2, the coating film 10 in the grooves 9 and 9' weighs approximately 30 g per square meter, and the coating film 10 in the grooves 9 and 9'
A coated veneer veneer 11 was obtained in which the coating film other than the portions was approximately 20 g per square meter. (See Figure 4) Using this coated veneer veneer 11 as a core material, the front plate 7 and back plate 8 were polymerized and hot-pressed to create plywood.
The degree of adhesion between the layers on both longitudinal sides of the plywood increased, and there was no peeling phenomenon.

Furthermore, as a result of cutting the plywood from its longitudinal center into a scarf shape, the degree of adhesion between the layers at the sharp parts increased, and there was no peeling phenomenon.

In the above embodiment, the position where the scarf surface is formed is set at the center, and the grooves 9, 9' are formed at the center of the upper and lower applicator rolls 1, 2.
This position is arbitrary, and the width tends to be slightly larger than that of the grooves 9, 9' near both sides.

Further, in this embodiment, for convenience, the explanation is made using plywood, but the same effect can be obtained with a laminated veneer material.

As described above, according to the method of the present invention, the defects such as the peeling phenomenon caused by insufficient adhesion of the longitudinal sides of the plywood when making it or the sharp parts when cutting the scarf can be fixed at any position of the coating roll. It can be wiped away by an extremely simple method of forming grooves, which greatly contributes to improving workability and quality.

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram showing a roll spreader for plywood, FIG. 2 is an explanatory diagram showing a scarf shape, FIG. 3 is a front view showing an embodiment of the method of the present invention, and FIG. FIG. 2 is a plan view of a veneer veneer subjected to the method of the present invention. 1, 2... Upper and lower application rolls, 3... Veneer veneer, 4, 5... Upper and lower doctor rolls, 6... Roll spreader for plywood, 9, 9'... Grooves, 11...
Painted veneer veneer.

Claims (1)

[Claims] 1. A roll spreader for plywood consisting of a rotatably supported application roll and a doctor roll arranged in parallel to the application roll so as to be able to move forward and backward to regulate the amount of adhesive applied to the surface of the veneer veneer,
After forming grooves of arbitrary width and arbitrary depth on the circumferential surface of a plurality of places at arbitrary intervals in the longitudinal direction of the coating roll, and regulating the desired adhesive application amount by moving the doctor roll back and forth, A method for applying adhesive to a veneer veneer, characterized by locally transferring a larger amount of adhesive to a desired location on the veneer veneer surface than to other surfaces.