JPH0754553A - Warpage prevention method for door having flush structure - Google Patents

Abstract

PURPOSE:To prevent the occurrence of warpage by coating the reverse side of a woody decorative sheet with resin capable of forming a hardened film via reaction with moisture at the time of pasting the sheet to both sides of a woody core material. CONSTITUTION:A non-permeable and non-homogeneous sheet such as a vinyl chloride decorative sheet 1b is pasted to the surface of a plywood 1a. Then, the reverse side of the plywood 1a is coated with resin 3 capable of forming a hardened film via reaction with moisture, such as polymethylene polyphenyl polyisocyanate, thereby preparing a woody decorative sheet 1. Thereafter, the sheet 1 is pasted to both sides of a woody door core material 2, thereby preparing a door X. When the door X is used, the resin 3 reacts with moisture contained in the air or the woody material to form a waterproof hardened film, thereby preventing additional moisture absorption and release. According to this construction, warpage can be reduced, and easy and low-cost production can be ensured.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a warp prevention method for a door having a flash structure.

[0002]

2. Description of the Related Art In most conventional flash doors, a thin plywood surface is laminated with veneer, decorative paper, vinyl chloride sheet, etc. on both sides of a core material made of a wood base material. .

The door is hinged at the boundary between two spaces under different environmental conditions without fixing the door itself with nails or adhesives.
Since it is placed in a relatively free state with rails, hanging metal fittings, etc., when the two environmental conditions are different, it is susceptible to warping and deviation due to the influence of temperature and humidity, and generally the thinner the door is Sliding doors are more likely to warp than doors.

Generally, since wood materials are more susceptible to humidity than temperature, it is thought that sticking a PVC sheet is more water and water impermeable than coating the surface, and is effective in preventing warpage. , Which is attached only to one side of the decorative plywood,
Not enough effect, especially in case of sliding door, 2
Since the doors are arranged on a fixed rail, even if slight warpage occurs, they are rubbed against each other and the defects are likely to stand out.

Considering the environmental conditions of the room and the corridor, in the warm winter, the room side becomes hot and humid as shown in FIG. 3, the corridor side becomes cold and low humidity, and vice versa in the cool summer. .

Assuming winter, a wooden door absorbs high temperature and high humidity in a flush door using a muku wood door or a veneer-attached decorative plywood. Therefore, the door is warped as shown in FIG. 3B. To do.

However, a flash door using a decorative plywood to which a water-impermeable / non-moisture-permeable sheet is adhered is warped as shown in FIG.

Since the water-impermeable / non-moisture permeable sheet is used, it does not absorb the moisture on the humid side, but the high temperature in the room pushes the moisture in the door to the corridor side, and the moisture in the door is absorbed. Experiments have revealed that the movement of the corridor causes the water in the corridor to rise and cause a warp like A.

Therefore, Japanese Patent Application No. 3-81622 and Japanese Patent Application No. 5162
No. 90397 discloses a method of preventing warpage by interposing a moisture-proof sheet between a frame material and a face material, or by sticking a water-impermeable / non-moisture-permeable sheet on both sides of a wooden board.

That is, a waterproof / moisture-proof sheet is attached to the back surface of a wooden decorative board, but of course the makeup is also applied to the front surface, so if a laminator is used, the production volume will be halved, or a large machine will be added. However, there is a drawback in that it is necessary and that it takes labor and cost even if other methods are used.

[0011]

SUMMARY OF THE INVENTION Therefore, the present invention is to develop a method for preventing warpage in a door having a flash structure, in which a water-impermeable / non-moisture-permeable layer is easily and inexpensively formed on the back surface of a wooden decorative board.

[0012]

According to the method of the present invention, in a door having a flash structure in which a wooden decorative board is attached to both sides of a core material made of a wooden base material, the back surface of the wooden decorative board is exposed to air or an adherend. This is a method to prevent warpage in a door with a flash structure, which is characterized by applying a resin layer that reacts with water to form a cured film. Also, a non-water-permeable / non-moisture-permeable sheet is attached to the surface of a wooden decorative board. The substance that reacts with the moisture in the air or the adherend to form a cured film is polymethylene polyphenyl polyisocyanate.

[0013]

In the method of the present invention, in air or adherend (wood material)
By applying a resin that reacts with the water contained in to form a cured film on the back surface of the wooden board, the wooden material normally has a water content of 14 to 15% if left unattended.・ Varies due to changes in environmental conditions such as humidity,
The wood material for absorbing and releasing moisture expands and contracts, causing warpage and deviation,
This resin reacts with the water that is the basis of this warpage to form a hardened film, so that the wood board cannot absorb and release new water and is stable.

An example of the resin is polymethylene polyphenyl polyisocyanate, the structural formula of which is shown below.

As the curing reaction, the reaction steps of (1) to (4) shown in the following Chemical formula 2 can be considered, and as shown in (4), the terminal NCO group finally becomes an amine group and is cured. Ends.

[0016]

[Chemical 1]

[0017]

[Chemical 2]

The cured coating contains many urea bonds, is a strong bond, and is resistant to hydrolysis, so that the cured coating has excellent water resistance.

Since such a resin has a low viscosity and has a good permeability into a wood material, the surface of the resin does not become sticky even if it is applied with a sponge roll coater, and it does not block even if it is immediately stacked. Since the cured film is formed by leaving it alone, it is possible to move to the next step quickly, and it is possible to provide the effect at low cost without requiring large-scale equipment or a large number of people.

[0020]

EXAMPLE A first example, which is an example of the present invention, will be described in detail with reference to the drawings. On the surface of a plywood (1a) having a width of 910 × a height of 2100 mm and a thickness of 2.7 mm, a 0.15 mm thick PVC decorative sheet (1b) is formed. ) Is attached with an ethylene vinyl acetate adhesive, two wooden decorative boards with a thickness of 2.85 mm are prepared, and polymethylene polyphenyl polyisocyanate [trade name: KU663 (Konishi Co., Ltd.) is provided on the back surface of these wooden decorative boards. (3) was applied with a sponge roll coater at a rate of 7 g / scale ² , immediately stacked, and left standing overnight.

On the other hand, as an example of the core material, a width of 30 mm
× A flash door core material (2) as shown in Fig. 4 is made of LVL (single plate laminated material) having a thickness of 21 mm, and the wood decorative board (1) is attached to both sides of the door core material (2) with ethylene. A door (X) of width 854 × length 2003 × thickness 26.7 mm is created by pasting together with a vinyl acetate adhesive, and 1 mm thick edge material (4) is attached to both wood end faces.
I stuck it.

As shown in FIG. 3, this door was placed at the boundary between two rooms, and an environmental test was conducted to measure the degree of warp of the door. Conditions Room side 30 ℃ 80% Corridor side 20 ℃ 60% Leave time 10 days

Next, a comparative example will be described.
In, a wooden flush board is produced by omitting the application of the resin on the back side, and becomes a normal flush door.

Also in Example 2 and Comparative Example, the same environmental test as in Example 1 was carried out to measure the degree of warpage. When the arrow height of the warp was measured at the center point of the height, the results shown in Table 1 were obtained. It was The situation is shown in FIG. In addition, A in FIG.
The arrow height of the warp of B is +, and the bow of B is −.

[0025]

[Table 1]

[0026]

EFFECTS OF THE INVENTION According to the present invention, a resin which reacts with the moisture of the adherend in the air to form a cured film is applied to the back surface of the wooden decorative board, which can be seen from the difference between the example and the comparative example. As described above, the method of the present invention can manufacture a door with extremely small warpage in view of the results of environmental tests, and further, if a non-water-permeable, non-moisture-permeable sheet is attached to the surface of the wooden decorative board, The effect can be improved, and further, it can be carried out easily and without any trouble and cost, which is an extremely beneficial effect.

[Brief description of drawings]

FIG. 1 is a side view showing an embodiment of the present invention.

FIG. 2 is a side view showing a conventional example of the present invention.

FIG. 3 is an explanatory diagram showing a location of an environmental test of the present invention.

FIG. 4 is a partially cutaway front view showing an embodiment of the present invention.

FIG. 5 is a graph showing the degree of door warpage in the environmental test of the present invention.

[Explanation of sign]

 1 Wooden decorative board 1a Plywood 1b PVC decorative sheet 2 Flash door core material 3 Resin layer 4 Edge material X Door

Claims (3)

[Claims] 1. A door having a flash structure in which a wooden decorative board is attached to both sides of a core material made of a wooden base material, and a cured film is formed on the back surface of the wooden decorative board by reacting with air in the air or moisture of an adherend. A method for preventing warpage in a door having a flash structure, which comprises forming a resin layer. 2. The method for preventing warpage in a door having a flash structure according to claim 1, wherein a water-impermeable / non-moisture-permeable sheet is attached to the surface of the wooden decorative board. 3. The method according to claim 1 or 2, wherein the substance that reacts with the moisture in the air or the adherend to form a cured film is polymethylene polyphenyl polyisocyanate. Warp prevention method for doors with flash structure.