JP2593779B2 - Floor material - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to flooring.

[0002]

2. Description of the Related Art Conventionally, as a floor material substrate, there has been known a floor material in which a plywood, a single laminated board (LVL) or the like is used as a substrate and a decorative sheet such as a veneer is adhered to the surface thereof. I have.

[0003]

However, this substrate is
Due to the lamination and production of veneers made of natural wood stripped thinly, the issue of depletion of natural resources has become a major issue worldwide, making it difficult to cut down the raw wood, and deteriorating the quality of the raw wood As a result, it becomes difficult to obtain a large number of high-quality veneers used for veneers, and it becomes difficult to supply a large number of high-quality substrates to the market. This problem is expected to become more serious in the future, and it is eager to provide a substitute for flooring substrates.

As a general construction of flooring, a decorative veneer is adhered to the front side of the substrate by heat and pressure, but the surface on which the decorative veneer is adhered is heated to a higher temperature than the back side. Therefore, a large amount of moisture is released from the front surface side of the substrate to the back surface side.

[0005] For this reason, on the surface side, the substrate shrinks due to the release of moisture, and as a result, a phenomenon is observed in which the entire flooring material warps in a valley warp shape in which the surface side is concave in the substrate length direction. Further, when the buffer sheet is stuck on the back surface side by cold pressure, the moisture in the adhesive used at this time is absorbed by the back surface of the substrate. Therefore, on the rear surface side, the substrate expands due to the absorption of moisture, and valley-like warpage is promoted.

The floor material that has been warped in a valley-like manner is fixed to the floor base surface while forcibly correcting the warp with a fixing means using an adhesive or nailing at the time of construction, which makes the construction extremely difficult. In addition, even when the floor material is fixed in a flat shape, the floor material still has a force to return to the original valley warp shape, so the abutting portion that is insufficiently fixed floats up or gradually as time elapses. However, a problem arises in that the butted portion rises to damage the wooden edge of the butted portion.

[0007]

DISCLOSURE OF THE INVENTION The present invention provides a novel flooring material which can be used as a substitute for a substrate made of a veneer, and has been accomplished as a result of diligent efforts to supply a flat flooring material. It is a thing.

That is, according to the present invention, in a wood fiber board having a hard layer having a higher specific gravity than the center layer in the thickness direction on the front and back layers, a groove deeper than the thickness of the back side hard layer is formed on the back side, and a decorative face is formed on the front side. It is a floor material on which a layer is formed.

An embodiment of the flooring material of the present invention will be described below with reference to the drawings. FIG. 1 shows a longitudinal sectional view of the flooring material of the present invention. As shown in FIG. 1, the flooring material of the present invention comprises:
Hard layers 11 and 12 are formed on the front and back layers, and a center layer 13 is formed between them. The wood fiber board 1 obtained by integral molding is used as a substrate.

The hard layers 11 and 12 formed on the front and back layers of the wood fiber board 1 have an average specific gravity of 0.8 to 1.
4 g / cm ³ , and the specific gravity of the central layer 13 between 0.4 g / cm ³ and 0.75 g / cm ^3.
1 and 12 are at least 0.1 in comparison with the specific gravity of the central layer 13.
1 g / cm ³ or more, preferably 0.2 to 0.8 g / cm ³
It is preferable to have a specific gravity difference of

When the amount is less than the above range, the stress described later hardly occurs, and the object of the present invention cannot be achieved. The average specific gravity of the whole wood fiber board is 0.1.
It can be used for ^{4g / cm 3 ~1.0g / cm 3} .

When the specific gravity is less than 0.4 g / cm ³ , the strength as a substrate is insufficient and the substrate cannot be used as a floor material. On the other hand, if it is larger than 1.0 g / cm ³ , the weight of the flooring material becomes large, and it becomes difficult to handle the construction material, which is not preferable.

Furthermore, when nailing, the nail is hard and the nail is hard to be driven. FIG. 1 shows an example in which the hard layers of the front and back layers are both exposed.

Using such a wood fiber board 1 as a substrate, a decorative layer 3 is formed on the surface side thereof. Since the decorative layer 3 is stuck by heat and pressure via an adhesive, the front and back surfaces of the plate material are heated and pressed. However, the surface side on which the decorative layer 3 is stuck is used to cure the adhesive. The back side is heated to a higher temperature than the back side, and the front side releases a greater amount of moisture from the back side, and as the water content on the front side decreases, the front side shrinks and the substrate becomes decorative. A valley warp occurs in the length direction having a large dimension so that the surface on which the layer 3 is adhered is concave.

The decorative layer 3 formed on the front side of the substrate may be a natural veneer obtained by cutting natural wood, an artificial veneer, a nonwoven fabric, paper, a veneer sheet lined with a synthetic resin sheet, or a decorative paper. And a decorative sheet such as an impregnated paper, a nonwoven fabric, a synthetic resin sheet, or the like, which is formed by bonding with an adhesive by hot pressing.

Further, an overcoat layer can be provided on the surface of the decorative layer 3. By adding an abrasive to the overcoat layer, the wear resistance of the surface can be improved.
Further, a groove may be formed on the surface of the decorative layer 3 according to the switching of the decorative layer 3 as necessary. The groove is U groove, V groove,
The cross-sectional shape such as a semi-circular groove is provided in an arbitrary shape.

In a wood fiber board having a large specific gravity difference in one board, the wood fibers are compressed and fixed in a very dense state in a portion having a high specific gravity. Will be inherent.

However, since a portion having a high specific gravity, in particular, a hard layer, in which a stress to be expanded is present, exists symmetrically at two places of a surface layer and a back layer with respect to a center in the thickness direction of the substrate, the front and back layers are hardly separated. In both cases, the same stress is applied to expand, and as a result, the stresses are balanced with each other, and the wood fiber board maintains a flat state.

As shown in FIGS. 2a, 2b, and 2c, a wood fiber board white having hard layers 51 and 52 on the front and back layers similar to that used as a substrate of the flooring material of the present invention, as shown in FIGS. When the sheet is cut into two sheets at the center plane, each sheet has one hard layer, the balance of the stress is lost, and the stress existing in each hard layer acts as an expansion force to cut the sheet. The plate material 5a on the front side is extended by the expansion force due to the stress inherent in the hard layer 51 on the front side, and the plate material is stretched in the length direction so that the cut surface is concave and the surface side on which the hard layer 51 on the surface exists is convex. Warp and back plate 5
b indicates that the plate material is warped in the length direction so that the back surface side where the hard layer 52 of the back layer having the cut surface is concave becomes convex is formed by the expansion force due to the stress inherent in the hard layer 52 on the back surface side. A phenomenon occurs.

It is confirmed from the warpage caused by this cutting that the above-mentioned stress is inherent. In addition, since the warping direction occurs in the length direction, it can be seen that the stress in the length direction of the dimension of the wood fiber board is stronger than the stress in the width direction of the shorter dimension.

FIG. 1 shows that the decorative layer 3 is formed on the front side of the wood fiber board 1 having the hard layers 11 and 12 having the specific gravity higher than the center layer 13 in the thickness direction on the front and back layers. This is a flat flooring material in which a groove 2 is formed on the back surface side in a width direction so as to be deeper than the thickness of the hard layer 12 as the back layer and to divide the hard layer.

This is because, by forming the groove 2 on the back surface side, the stress that is about to expand in the hard layer 12 of the back layer is divided, and the expansion due to the stress in the length direction that worked on the back surface side. The force is smaller than the expansion force due to the longitudinal stress on the surface side.

For this reason, the wood fiber board 1 generates a force to warp in the longitudinal direction so as to make the back surface side on which the groove 2 is formed concave. Therefore, although the valley warp is formed by forming the decorative layer 3 on the surface of the wood fiber board 1, the groove 2 is formed at least in the width direction on the back side to form the mountain warp. Since a warping force is generated, a flat flooring can be obtained.

As shown in FIG. 3, a buffer sheet 4 may be attached to the back surface of the substrate for the purpose of imparting soundproofing performance. As the buffer sheet 4, for example, a polyethylene resin, a polypropylene resin, a polyurethane resin,
A foam, a nonwoven fabric, a foam rubber sheet, or the like of a synthetic resin such as a polystyrene resin or a vinyl chloride resin can be used.

In these foamed sheets, the foamed structure is destroyed by heating, and the non-woven fabric is fused with fibers.
Since the buffering property is impaired due to the destruction of the three-dimensional network structure, the attachment to the substrate is generally performed via an adhesive without applying heat by cold pressure.

Therefore, in the case of a conventional substrate in which a single veneer is laminated, the moisture in the adhesive is absorbed by the back surface of the substrate, and the back surface of the substrate expands due to the absorption of moisture and the back surface becomes convex. A force for warping in a valley warp shape in the longitudinal direction is generated.

However, since the hard layer 12 having a high specific gravity is formed on the back side of the wood fiber board 1, it is excellent in water impermeability as compared with the veneer board, and almost prevents the moisture of the adhesive from penetrating. it can. This non-water-permeability is particularly excellent when the hard layer 12 on the back side is exposed, and is preferable.

Further, since the groove 2 is formed in the width direction on the back surface side, expansion due to slightly absorbed moisture is limited to expansion in the block divided by the groove. Therefore, the wood fiber board 1 can maintain a flat state without warping in a valley warp shape.

By forming the groove 2 on the back surface side, the rigidity (Young's modulus) of the wood fiber board 1 as a substrate is reduced, and additionally, the space of the groove 2 works as a soundproof room and the soundproof performance is also improved. Will be improved. Further, the groove 2 can be formed even in the longitudinal direction of the substrate as needed.

The hard layers 11 and 12 having a higher specific gravity than the central layer and excellent in tensile strength and compressive strength as described above.
By using the wood fiber board 1 provided on the front and back layers as a substrate, the board has a high surface hardness, is hardly scratched, has excellent bending strength as a whole board, and has a very small amount of deflection under a unit load.

The hard layers 11 and 12 are used to increase the water content of the wood fibers in the front and back layers during the heating and pressing in the process of manufacturing the wood fiber board by the dry method, or to provide an adhesive to the wood fibers. By increasing the addition amount, a layer having a higher specific gravity can be locally formed as compared with other portions. Such a wood fiber board has excellent stability in that the dimensional change rate per 1% of the water content is equal in the length direction and the width direction and is 0.03 to 0.04%.

Further, by exposing at least the hard layer, which is the highest specific gravity part on the surface layer side, the surface performance of the substrate is 10 times or more as high as that of the case where plywood is used as the substrate, and the surface hardness is higher. Has a strength that is 2 to 4 times as high as that of a flooring material, and exhibits excellent characteristics such as not being easily dented by a local impact applied from the surface.

The wood fiber used as the raw material of the wood fiber board 1 used as the substrate of the present invention is a softwood such as pine, cedar, cypress, etc. or a hardwood such as lauan, kapole, chestnut, poplar or the like. Use wood fibers obtained by defibrating wood chips obtained by cutting off parts or waste materials that cannot be used as waste, and waste materials such as sander dust, saw dust, chip dust, etc. generated during the manufacture of wood fiber board. Can be.

The wood fiber board used as the substrate of the present invention is:
For example, in the process of manufacturing a dry wood fiber board, a wood fiber that has been defibrated and added with an adhesive and dried is deposited on a screen conveyor by a forming device, and each thickness is adjusted by a shaving rotor, and then temporarily pressed, and then temporarily pressed. A wood fiber mat is obtained, and then a fixed size mat cut to a certain size is heated and compressed to obtain a wood fiber board having a hard layer having a higher specific gravity in the front and back layers than in the center layer.

The obtained wood fiber board has a low specific gravity thin surface layer formed by pre-curing the adhesive at the time of heating and pressing.
Sanding removes the low-density thin film surface layer,
The hard layer can be exposed. .

A nonwoven fabric coated or contained with water on the upper and lower surfaces of the fixed-size mat obtained in the same manner as above.
By placing a water-retaining sheet-like material such as paper or cloth and heating and pressing it, the water applied or contained in the sheet-like material is heated and pressed while being held in the wood fibers of the front and back layers. A hard layer having a very high specific gravity can be formed on the front and back surfaces.

As a forming apparatus for depositing wood fibers on the screen conveyor, three forming machines for separately forming the back layer forming wood fibers, the center layer forming wood fibers, and the surface layer forming wood fibers and depositing them on the screen conveyor. A device was provided, for example, adding 3 to 5% by weight of an adhesive to the center layer forming wood fiber, and adding 10 to 30% by weight of an adhesive to the surface layer forming wood fiber and the back layer forming wood fiber. By heating and pressing later, the specific gravity of the hard layer can be increased and the strength can be improved in accordance with the above-described method of forming the hard layer using moisture.

In a similar forming apparatus,
2-8 as the back layer forming wood fiber and the surface layer forming wood fiber
The coating agent containing or containing the weight% sizing agent is supplied to the forming apparatus, and the back layer, the middle layer, and the surface layer
After laminating and stacking the layers of wood fibers, the content of the sizing agent in the surface layer and the back layer can be adjusted to 2% by weight or more by heating and pressing.

As described above, the front and back surfaces of the wood fiber board are
A hard layer having higher specific gravity and higher water impermeability than the center layer is formed. In addition, since the specific gravity distribution occurs even in the hard layer of the obtained wood fiber board, sanding is performed as necessary, and the layer (surface) having a particularly high specific gravity among the hard layers is exposed to the surface, so that the water impermeability, Performance such as bending strength and deflection is further improved.

[0040]

The flooring material of the present invention uses, as a substrate, a wood fiber board obtained by heating and pressing wood fibers, and this wood fiber board can be used to crush or defibrate a raw wood that has a drawback that cannot be used as a single board. Since it can be obtained by using what is done, resources can be used effectively and it can help to prevent the destruction of nature.

Further, a decorative layer is formed on the surface of such a wood fiber board, and the water is released from the wood fiber board at the time of forming the decorative layer. While a warping force is generated, a wood fiber board having a high specific gravity hard layer on the front and back layers, by forming a groove at least in the width direction so as to divide the back layer hard layer on the back side, Dividing the expansion force due to the stress existing in the back layer of the wood fiber board, breaking the expansion force that was taken between the front side and the back side, the force that the wood fiber board warps in a mountain warp shape As a result, the balance between the force of the wood fiber board to warp in a valley warp due to the release of moisture and the force of the wood fiber board to warp in a mountain warp due to the formation of a groove is balanced. It will be a nice flooring.

Even when a cushioning sheet is adhered to the back surface, the hard layer on the back side has excellent water impermeability, hardly absorbs moisture in the adhesive, and has a groove on the back side. As a result, the expansion due to the slightly absorbed moisture is limited to the expansion in the block divided by the groove, so that the wood fiber board does not warp.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view of a flooring material of the present invention,

2A is a cross-sectional view of a wood fiber board 5 having hard layers 51 and 52 on the front and back layers, and FIG. 2B is a cross-sectional view of the wood fiber board 5 shown in FIG. (C) a cross-sectional view showing a state in which the wood fiber board 5 of FIG.

FIG. 3 is a cross-sectional view of the flooring material of the present invention in which a buffer sheet 4 is adhered to the back surface.

[Explanation of symbols]

11, 12: hard layer, 13: center layer, 1: wood fiber board,
2: groove, 3: decorative layer, 4: cushioning sheet, 5: wood fiber board, 51, 52: hard layer, 5a: surface plate, 5b:
Plate material on the back side.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁶ Identification code Agency reference number FI Technical display location E04F 15/18 602 8702-2E E04F 15/18 602F

Claims (2)

(57) [Claims] 1. A wood fiber board having a hard layer having a higher specific gravity than the center layer in the thickness direction on the front and back layers, a groove deeper than the thickness of the back side hard layer is formed on the back side, and a decorative layer is formed on the front side. Becoming flooring. 2. A flooring comprising a wood fiberboard according to claim 1 and a buffer sheet attached to the back surface.