JPH06218877A - Manufacture of building board - Google Patents

Abstract

PURPOSE:To suppress the warpage of building board and facilitate the change of the thickness of medium-density fiber board layer itself by a method wherein medium-density fibers are sprinkled on the curved surface side of pre-curved plywood base material and, after that, through adhesive, bonded under pressure. CONSTITUTION:Medium-density fibers 3 are sprinkled on the front surface side of plywood base material 1, which is curved so as to project to the front surface side, or concretely spread all over a pressing board 2 below the plywood base material 1 by the thickness at the molding such as about 0.5-3.0mm. In addition, through adhesive such as one containing about 15% of urea-based resin, the base material 1 and the medium-density fibers are bonded together under pressure. Due to the curing shrinkage after the bonding under pressure, the curved surface side of the plywood base material is shrunk, resulting in compensating the curved state, which is shaped in advance in the plywood base material, with the curing shrinkage so as to suppress the development of the warpage in the building board, to which medium-density fibers are bonded under pressure.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a building board, and more specifically, a medium-quality fiberboard (Medium Den) on one side.
More specifically, the present invention relates to a method for manufacturing a building board provided with a city fiber board, and more specifically, while having a medium quality fiberboard layer on one side thereof, suppressing warpage thereof and avoiding peeling of the medium quality fiberboard layer, The present invention relates to a technique for easily changing the thickness of the plate layer itself.

[0002]

2. Description of the Related Art Conventionally, in order to obtain a building board having a medium quality fiberboard on one side, a medium quality fiberboard is laminated on a base plywood.

[0003]

By the way, when a medium-quality fiber board obtained by press-molding only medium-quality fibers with an adhesive is laminated and bonded to a plywood base material, for example, a medium-quality fiber produced after hot pressing is used. The contraction of the fiberboard causes the building board to warp, and delamination between the two tends to occur, and it is difficult for the medium-quality fiberboard to be manufactured as thin as 2.7 mm or less by the press manufacturing technology. Therefore, there is a problem that the thickness cannot be reduced below a certain level in a building board in which a medium-quality fiberboard is laminated on a plywood base material.

The present invention has been made in view of the above problems, and an object of the present invention is to provide a method for manufacturing a building board having a medium-quality fiberboard layer on one surface thereof. It is an object of the present invention to provide a method for manufacturing a building board, in which warp of the building board is suppressed, peeling of the medium fiber board layer is avoided, and the thickness of the medium fiber board layer itself can be easily changed.

[0005]

According to the present invention, a medium-quality fiber 3 is sprinkled on the protruding curved surface side of a plywood base material 1 which is bent in advance, and the medium-quality fiber 3 is pressure-bonded through an adhesive. It is characterized by that.

[0006]

The medium-quality fibers 3 sprinkled on the protruding curved surface side of the plywood base material 1 which has been bent in advance are pressure-bonded with an adhesive to reduce the curing shrinkage of the medium-quality fibers 3 after the pressure-bonding. Plywood base material 1
It is possible to effectively suppress the occurrence of warpage in the building board in which the medium-quality fibers 3 are pressure-laminated, by contracting the protruding curved surface side of the plywood substrate 1 and canceling out the pre-curved state in the plywood base material 1 and the curing shrinkage. To do. Moreover, the thickness of the medium-quality fiber 3 sprinkled on the plywood base material 1 can be freely adjusted to easily change the thickness of the building board A having the medium-quality fiberboard layer 3a. Then, as compared with a structure in which a medium-quality fiber board is laminated and bonded to the plywood base material 1, a structure in which the medium-quality fiber 3 is sprinkled on the plywood base material 1 and pressure-pressed via an adhesive is used. Peeling of the plate layer 3a is strongly prevented.

[0007]

Embodiments of the present invention will be described below in detail with reference to the drawings. The plywood base material 1 is made of lauan wood or coniferous wood (such as Yonematsu), and may be ordinary plywood in which a plurality of veneers are laminated in a direction in which their fiber directions are orthogonal to each other. And Figure 2
In the plywood substrate 1 of 3 plies of (a), 5 plies of (b), and 7 plies of (c), the ratio of the thickness of the front single plate a to the back single plate b By changing the above, the base plywood 1 can be bent so that the surface veneer a side is the protruding side. The arrow height h indicating the degree of warp is 3 shaku x 6 shaku, and the thickness is 3 ply,
When the thickness ratio of the front surface veneer a is 1.0 with the thickness of 2.5 mm to 20 mm for 5 plies and 7 plies and the thickness ratio of the back surface veneer b is 0.9, the arrow height is 5 mm. ~ 15 mm, back single plate b
If the thickness ratio of is 0.8, the arrow height is 20 to 25 mm, and if the thickness ratio of the back single plate b is 0.7, the arrow height is 35 to 40 mm, the thickness ratio of the back single plate b is If it is 0.6, Yataka is 40-
If the thickness ratio of the back single plate b is 50 mm, the arrow height is 50 to 60 mm. If the thickness ratio of the back single plate b is 0.4, the arrow height is 80 to 100 mm, the back single plate. If the thickness ratio of b is 0.3, the arrow height will be 100 to 110 mm. And
These values vary somewhat depending on the tree species. The warp of the substrate plywood 1 is due to the fact that the single plates are laminated with an adhesive,
Moisture in the adhesive is absorbed to expand the veneer, and the degree of expansion increases as the thickness decreases. The greater the degree of expansion, the more the water is scattered during heating and pressurization, and the greater the degree of shrinkage, and the greater shrinkage causes the substrate plywood 1 to warp.

In this way, the surface side of the base material plywood 1 is bent so that the surface side becomes a projection, and the medium quality fibers 3 are sprinkled on the surface side of the base material plywood 1, that is, under the plywood base material 1 and above the press substrate 2. Fiber 3
Is laid with a thickness such that the thickness at the time of molding is, for example, about 0.5 mm to 3.0 mm. Such medium fibers 3 are pulp fibers of vegetable fibers, short fibers are powdery fibers of 2.0 mm to 3.0 mm or less, and long fibers are about 10.
It is about 0 mm. And the thickness is 0.05 ~
It is about 0.15 mm or 0.1 mm. 1 adhesive
Include about 5%. Adhesives that meet the JIS T ₁ water resistance test, that is, melamine, phenol, epoxy resin, and T
Those that pass the ₂ standard water resistance test, that is, urea-based resins are used. And the applied pressure is 30 kg / cm ^2.
The time is about 1 minute to 5 minutes, and the average is about 2 minutes to 3 minutes, and it takes more time as the thickness increases. C in the figure
Is a decorative sheet such as a veneer.

As described above, the medium-quality fibers are sprinkled on the protruding curved surface side of the plywood base material 1 which is bent in advance, and the medium-quality fibers 3 are pressure-bonded through the adhesive, so that curing after pressure-bonding is performed. The projecting curved surface side of the plywood base material 1 is shrunk by the shrinkage, and the preformed bent state of the plywood base material 1 and the curing shrinkage cancel each other, so that the building board A in which the medium-quality fibers 3 are laminated under pressure is formed. The warp is effectively suppressed. Moreover, the thickness of the medium-quality fiber 3 sprinkled on the plywood base material 1 can be freely adjusted to obtain the medium-quality fiberboard layer 3
The thickness of the building board A provided with a can be easily changed.
Furthermore, the peeling of the medium-quality fiberboard layer 3a is sufficiently strongly prevented, and in such a case, since the medium-quality fiber 3 is sprinkled onto the plywood base material 1 and pressure-bonded, it is possible to use the technique for manufacturing a medium-quality fiberboard. The cost is reduced by using the plywood base material 1.

[0010]

As described above, according to the present invention, since the medium-quality fibers are sprinkled on the protruding curved surface side of the plywood base material which is previously curved and the medium-quality fibers are pressure-bonded through the adhesive, By pressing and bonding the medium fibers sprinkled on the protruding curved surface side of the bent plywood base material 1 with an adhesive, the protruding curved surface side of the plywood base material is contracted by the curing shrinkage after such pressure bonding. The advantage that the preformed curved state of the plywood base material and the curing shrinkage cancel each other out, and it is possible to effectively suppress the warpage of the building board in which the medium-quality fibers are laminated under pressure. There is. Moreover,
Compared to the conventional structure in which pressure-molded medium-quality fiberboard is laminated on a plywood base material, the thickness of the medium-quality fibers sprinkled on the plywood base material can be adjusted freely, and a construction with a medium-quality fiberboard layer Compared to a structure in which the thickness of the board can be easily changed and moreover, the medium-quality fiberboard layer is laminated and adhered to the plywood base material, the medium-quality fiber is sprinkled on the plywood base material and pressed by an adhesive. Due to the constitution of molding, the peeling of the medium fiberboard layer can be prevented sufficiently firmly, and furthermore, since the medium quality fiber is sprinkled on the plywood base material 1 and pressure-bonded, the manufacturing technology of the medium quality fiberboard is used. Can, plywood substrate 1
There is an advantage that the cost can be reduced by using.

[Brief description of drawings]

1 shows an embodiment of the present invention, showing the action of forming a medium-quality fiber on one side of a plywood substrate, (a) is an operation explanatory diagram,
(B) is sectional drawing of the manufactured building board.

2A is a cross-sectional view of a 3-ply plywood base material, FIG.
Is a cross-sectional view of a 5-ply plywood base material, and (c) is a cross-sectional view of a 7-ply plywood base material.

[Explanation of symbols]

 1 Plywood substrate 3 Medium fiber

Claims (1)

[Claims] 1. A method of manufacturing a building board, comprising sprinkling pre-curved plywood base material with a medium-quality fiber on the protruding curved surface side and pressure-bonding the medium-quality fiber through an adhesive.