JPH07227814A - Wooden fiber composite material - Google Patents

Abstract

PURPOSE:To increase nail- or screw-retaining force in a wooden fiber board-like form such as intermediate-quality fiber board called MDF or particle board. CONSTITUTION:A wooden fiber composite material A is obtained by forming the front and rear layer parts 2, 2 of a wooden fiber plate-like forms 1, 1 with a density of 0.4 to 0.9kg/m<3> which is obtained by flattening wooden fiber or wooden scrapings such as intermediate quality fiber board called MDF or particle board, by a binder, in such a manner that the front and rear layer parts 2, 2 are of a higher density than an intermediate layer part 3. In addition, these layers are integrated into a single piece through a hot melt adhesive.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a composite integrated technique of wood fibers such as MDF called wood fiber, particle board and other wood fibers, and wood chips formed into a flat plate by a binder.

[0002]

2. Description of the Related Art Conventionally, wood fibers such as medium fiberboard and particle board called MDF, wood fibers such as particle boards, and wood fiberboard-like wood fiberboard-like materials for binders for building construction materials and furniture The body is used, but the screw / nail holding power is inferior compared to muku wood and plywood. This is because the above-mentioned wood fiber plate is formed into a plate by entwining wood fibers, wood chips with thermosetting resin adhesive such as phenol, melamine, urea, etc. and wood fibers. This is because it is less tenacious than other wood.

Therefore, the front and back layers of the wood fiber board are made to have a higher density than the middle layer, and a plurality of sheets are laminated and integrated, and the plurality of high-density layers are positioned on the side surfaces of the nails or screws, whereby side resistance and tightening are achieved. It is designed to improve the grip torque and improve the nail / screw holding force.

[0004]

However, if the front and back layers of the wood fiber board are made to have a high density, the hardness becomes large but the toughness is poor, and the vinyl acetate type, resorcin type, vinyl urethane type, acrylate type are used. Since it is laminated and integrated with an adhesive such as, the plasticity after curing the adhesive is small.

Therefore, after the nails / screws are embedded, if a lateral load is applied, the holding force becomes extremely lower than the initial holding force. Further, since the adhesive contains a solvent such as water or an organic solvent,
There is a defect that the solvent may permeate from the adhesive surface of the wooden plate to cause swelling or uneven water content, resulting in warpage.

The present invention has been made in view of the above problems, and provides a wood fiber composite material which has improved nail / screw holding power and prevents warpage that occurs when laminated and integrated.

[0007]

Therefore, in the wood fiber composite material of the present invention, according to claim 1, a plurality of wood fiber plate-like bodies in which the front and back layers are formed at a higher density than the middle layer are hot. According to a second aspect of the present invention, the hot melt adhesive is a sheet material, and in the third aspect, the hot melt adhesive sheet material is a large number of through holes. It is a structure having.

[0008]

With the above structure, the wood fiber composite material of the present invention is
Since a plurality of wood fiber board-like materials in which the front and back layers are formed at a higher density than the middle layer are laminated and integrated with a hot melt adhesive, the toughness of the high density layers in the front and back layers is improved. Even if it is small, the hot-melt adhesive is located at the interface and imparts toughness, and resists shear fracture from the side of nails and screws. Also, with hot-melt adhesives, the adhesive layer plasticizes due to frictional heat when embedding nails and screws, and enters the high-density layer between the nails and screws and the wood fiber board, so the load after embedding nails and screws On the other hand, it does not significantly decrease compared to the initial holding power. Further, since the above hot-melt adhesive is almost solvent-free, the surface of the wooden plate does not swell and the water content becomes non-uniform, so that no warpage occurs.

As described above, the present invention is characterized in that the holding force for fixing nails and screws is less reduced even during long-term use, and the warpage that occurs when the layers are integrated is small.

According to the second aspect, since the hot melt adhesive is made of a sheet material, an adhesive layer having a uniform thickness can be formed between the wood fiber board bodies, and stable nail and screw holding force can be secured. The warpage during lamination is also small.

According to the third aspect of the invention, since the hot melt adhesive is made of a sheet material having a large number of through holes, water can move between the adhesive layers even after the bonding and integration, and warpage is less likely to occur.

[0012]

EXAMPLES Next, examples will be described with reference to FIG. 1 of the present invention.
FIG. 1 is a side view of the wood fiber composite material A, which has a density of 0.4 to 0.9 kg / m of wood fibers and wood chips such as medium fiberboard and particle board called MDF with a binder.
³ the front and back layer portions 2 of the wood fiber board-like body 1, 1 molded into a flat plate shape formed densely than the middle section 3, are laminated and integrated through the hot-melt adhesive 4.

For example, the thickness is 4 to 15 mm and the density is 0.7 to
The density of the front and back layers 2 and 2 from the front and back layer of wood fiber board-like body 1 made of wood containing fiberboard 0.8 kg / ^{m 3} to a depth 1~2mm and 0.8~1.0kg / ^{m 3} The internal density is set to 0.6 to 0.7 kg / m ³ .

The hot melt adhesive 4 is obtained by adding a surfactant, an inorganic filler and a plasticizer to a base polymer such as an ethylene vinyl acetate copolymer resin, a polyolefin resin such as polypropylene and polyethylene, a polyamide such as nylon and a polyester resin. The composition is such that it melts at 100 to 200 ° C., and it is applied to one side of the wood fiber board 1 with an applicator or scattered in powder form at a coating amount of 1 to 200 g / m ² . The application form is appropriately selected from the whole surface, linear shape, and dot shape depending on the application and manufacturing process, but the hot melt adhesive 4 is made to exist at the positions corresponding to the nail and screw fixing positions.

According to the second aspect, the thickness of the hot-melt resin is melt-blended and extruded to form a film, or other support film, non-woven fabric, sheet-like material such as paper is laminated or impregnated with the hot-melt adhesive. 0.0
The wood fiber plate 1 having a diameter of 01 to 0.2 mm is placed on the upper surface of one wood fiber board 1, and the other wood fiber board 1 is placed on the wood fiber board 1 to be integrated by heating.

In the third aspect, as shown in FIG. 2, hot-melt resin is melt-blended and extruded into a film to form a large number of through holes 5, or a support film or a nonwoven fabric having through holes in advance. Thickness of hot-melt adhesive laminated or impregnated on paper or paper 0.00
Those having a diameter of 1 to 0.2 mm are integrated by the same method as described above. Moisture can be moved when the layers are integrated, and moisture or the like can be moved during long-term use to prevent warpage.

If a large number of thin wood fiber plate-like bodies 1 are laminated to obtain a wood fiber composite A having a predetermined thickness, a larger amount of the front and back layers 2 and 2 and the hot melt adhesive 4 are nailed.・
It is preferable because it can come into contact with screws and the holding power for nails and screws increases. (Example 1) As an experimental example, a thickness of 4 mm and a density of 0.8 k
g / m ³ A hot-melt adhesive mainly composed of ethylene vinyl acetate copolymer resin was melted to 100 ° C. by an applicator on a wood fiber plate made of a medium fiber board, and the coating amount was 40 g / m. Set it to ² and attach it, and then add a thickness of 9
Example 1 was obtained by laminating and integrating a medium-quality fiberboard having a size of 0.7 mm and a density of 0.75 kg / m ³ . (Example 2) A polyester resin hot melt film having a thickness of 0.04 mm was used in place of the molten hot melt adhesive of Example 1, and a thickness of 4 mm and a density of 0.8 kg.
/ M ³ The above film is arranged on a wood fiber board made of a medium fiber board, and a density of 0.75 kg with a thickness of 9 mm is placed on the film.
/ M ³ of a medium quality fiberboard was loaded, and hot pressing was performed at 130 ° C. for 10 minutes, and Example 2 was exited. (Example 3) Instead of the film of Example 2 above, the diameter is 1 m.
Example 3 was obtained in the same manner as in Example 2, except that a large number of m holes were used. (Comparative Example) As Comparative Example 1, a laminate was obtained in the same manner as in Example 1 except that a vinyl acetate emulsion adhesive having a solid content of 30% and a coating amount of 80 g / m ² was used. Comparative Example 2 has a thickness of 12 mm and a density of 0.75 kg / m ^3.
A wood fiber board made of a single-layer medium fiber board was used.

The 6 test pieces of Examples 1, 2 and 3, Comparative Example 1 and Comparative Example 2 were subjected to a wood screw holding force test in accordance with JIS A5906. As a result, the average value of the wood screw holding force was determined as in Example 1. Is 80.4 kgf and Example 2 is 84.0 kg.
f, Example 3 was 85.6 kgf, while Comparative Example 1 was 70.1 kgf and Comparative Example 2 was 47.8 kgf, showing the effect of the wood screw holding force of Examples 1-3. .
In addition, after embedding a wood screw in Examples 2 and Comparative Example 1 and applying a load of 10 kg from the side surface, a wood screw holding force test similar to the above was performed. As a result, Example 2 was 80.8 kgf and Comparative Example 1 Is 65.6 kgf, Example 2 is 3.8%, Comparative Example 1
Was 6.4% in strength reduction rate, and it was found that the examples had little effect on use. In addition, in Examples 1 to 3, there was no warp, but in Comparative Example 1, there was a sample in which warpage occurred.

[0019]

As described above, in the wood fiber composite material of the present invention, a plurality of wood fiber plate-like materials in which the front and back layer portions are formed at a higher density than the middle layer portion are intercalated with a hot melt adhesive. Since they are laminated and integrated, even if the high-density layers of the front and back layers have low toughness, the hot-melt adhesive is provided at the interface to impart toughness, and the nail / screw holding power is improved. In addition, since it penetrates between the high density layers of nails, screws and wood fiber board,
Even if the screw receives a load from the side surface, it does not significantly decrease compared to the initial holding force. Furthermore, since the hot melt adhesive is almost solvent-free, the surface of the wooden plate does not swell and the water content does not become non-uniform.

Therefore, the present invention has an effect that it exerts a high nail holding force on a member such as a door frame or furniture which needs to be nailed or screwed, and that the holding force is not deteriorated during long-term use. .

According to a second aspect of the present invention, in which the hot-melt adhesive is used as a sheet material, an adhesive layer having a uniform thickness can be formed between the wood fiber board members, a stable nail and screw holding force can be secured, and at the time of stacking. The warp of is also small.

Further, in the third aspect of the present invention, the hot-melt adhesive is a sheet material having a large number of through holes, so that moisture can be moved at the adhesive interface and warpage is reduced and reduced.

[Brief description of drawings]

FIG. 1 is a wood fiber composite material A according to claims 1 and 2 of the invention.
FIG.

FIG. 2 is a side view of a wood fiber composite material A according to claim 3 of the present invention.

[Explanation of symbols]

 A ... Wood fiber composite material 1 ... Wood fiber plate-like body 2 ... Front and back layer portion 3 ... Middle layer portion 4 ... Hot melt adhesive 5 ... Through hole portion

Claims (3)

[Claims] 1. A wood fiber composite material in which a plurality of wood fiber plate-like bodies having front and back layer portions formed at a higher density than the middle layer portion are laminated and integrated via a hot melt adhesive. 2. A wood fiber composite material obtained by laminating and integrating a plurality of wood fiber plate-like bodies having front and back layer portions formed at a higher density than the middle layer portion with a hot-melt adhesive sheet material interposed therebetween. 3. A plurality of wood fiber board bodies having front and back layer portions formed at a higher density than the middle layer portion are laminated and integrated through a hot melt adhesive sheet material having a large number of through holes. Wood fiber composite material.