JPH10109385A - Formaldehyde capture moistureproof sheet, and decorative plate and interior finishing member using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enable easy identification of front and rear surfaces and to securely prevent failure of erroneously sticking the front and rear surfaces by entirely or partly coloring at least one surface with color different from that of the other surface. SOLUTION: The formaldehyde capture moistureproof sheet is obtained by sequentially laminating, for example, a first fibrous layer containing formaldehyde capturing agent, a moistureproof layer 2 and a second fibrous layer 3 containing no formaldehyde capturing agent. At least its one surface such as, for example, the surface of the layer 1 is colored with color different from that of the other surface. The layer 1 uses a layer obtained by impregnating a fibrous sheet of paper or woven fabric with the capturing agent such as dicyandiamide. As moistureproofing agent 2, synthetic resin such as polyethylene is usable. The layer 3 uses by arbitrarily selecting from fibrous sheet such as paper or woven fabric containing no capturing agent.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is used for building materials such as wall materials, construction members, and fittings, and furniture, and captures formaldehyde generated from a base material or contained in indoor air. The present invention relates to a formaldehyde-trapping moisture-proof sheet for deodorizing and detoxifying and preventing generation of warpage due to moisture absorption and release of a substrate.

[0002]

2. Description of the Related Art In recent years, solid wood made of natural wood has become more and more expensive due to depletion of resources as a structural material, wall material, building material, building material such as fittings, furniture and the like. The quality of materials such as plywood, laminated wood, particle board, hard board, medium density fiber board, etc. is inexpensive and natural wood with inferior wood grain design. Various synthetic wood materials obtained by processing this resin are increasingly used.

However, many of the above synthetic wood materials use an adhesive containing formaldehyde such as a urea resin adhesive at the time of production, and free formaldehyde or formaldehyde due to decomposition during heat treatment remains after production. Therefore, in buildings using such building materials,
Even after completion, building materials release formaldehyde, which is harmful to health and has a peculiar unpleasant odor, which may cause occupants and users to suffer health problems such as allergic symptoms and discomfort, which is regarded as a problem in some cases. .

[0004] As means for solving this problem,
(A) a method for producing a synthetic wood material using an adhesive that does not contain or generate formaldehyde; (B) a method for producing a synthetic wood material using an adhesive containing a formaldehyde scavenger; and (C) synthesis. A method of applying or impregnating a formaldehyde scavenger after the production of a wood material, (D) a method of using an adhesive containing a formaldehyde scavenger at the time of attaching wallpaper or decorative paper to synthetic wood materials, (E) a formaldehyde scavenger And (F) a method in which paper impregnated with a formaldehyde scavenger is used for packing synthetic wood materials and members.

However, among the various methods described above,
(A) has a problem that there is no adhesive which is satisfactory in performance and price, and (B) has a problem that small lot production only for a specific application which dislikes the generation of formaldehyde increases costs. , (C) requires a special coating machine and has the problem that the process becomes complicated.
(D) has a problem in that it is necessary to use an adhesive only for a specific application, and material management and process management become complicated. (E) limits the types of applicable members.
There is a problem that the effect is not obtained with respect to the emission of formaldehyde from the surface side of the member, and (F) naturally has a problem that the effect is lost by unpacking.

In order to obtain a permanent formaldehyde trapping effect by a simple method, there has been proposed a method of attaching (G) a decorative paper based on a paper impregnated with a formaldehyde trapping agent (Japanese Patent Publication No. Sho 52). -134).
However, in this method, a formaldehyde trapping effect can be obtained, but a moisture-proof effect of preventing the occurrence of warpage due to moisture absorption and release of the substrate cannot be obtained.

That is, in the case of a large flat interior member such as an interior door or a kitchen door, for the purpose of cost reduction and weight reduction, the frame cores (frame cores) formed by combining square members vertically and horizontally are provided on the front and back sides. A member having a so-called flash structure in which plate materials such as a veneer and a plywood are laminated is widely used.
However, when a member having such a flash structure is placed at a boundary between two spaces having different environmental conditions such as temperature and humidity, the two members at the front and back have different expansion and contraction due to moisture absorption and desorption, so that the member as a whole warps. There was a problem that would. In order to solve this problem, a method has been proposed in which a moisture-proof (non-water-permeable and non-water-permeable) sheet is laminated on both the front and back surfaces of the plate material on the front and back sides of the member having the flash structure (Japanese Patent Laid-Open Publication No. HEI 9-260572). 6-272455).

In order to achieve the two effects of the formaldehyde-trapping effect and the moisture-proofing effect by a single means, the present inventors have already prepared a base layer such as paper containing a formaldehyde-trapping agent. Proposed a formaldehyde-capturing moisture-proof sheet formed by compounding with a moisture-proof layer such as a synthetic resin (Japanese Patent Application No. 8-15898).

As the formaldehyde-capturing moisture-proof sheet, various forms are used depending on the specific application. For example, there is a sheet which has a design such as wood grain and also functions as a decorative sheet. However, for example, since it is a place that is invisible to human eyes after assembling, it is not necessary to design it for attaching to the back surface (inner surface) of the plate material that constitutes the front and back surfaces of the flash structure member described above.
By combining a moisture-proof layer such as a synthetic resin with a fibrous layer such as paper containing a formaldehyde scavenger, the purpose can be sufficiently achieved.

[0010] However, this formaldehyde-capturing moisture-proof sheet needs to be adhered on one side to a plate material and on the other side to the frame center. However, synthetic resin having excellent moisture-proof properties used as a moisture-proof layer is generally used in wood processing. Poor adhesion to vinyl acetate emulsion adhesives that are widely used in the industry and the construction industry. Therefore, a sheet having a three-layer structure in which a first fibrous layer containing a formaldehyde scavenger is arranged on one surface of a moisture-proof layer, and a second fibrous layer not containing a formaldehyde scavenger is arranged on the other surface, There are many examples to use.

By the way, the above-mentioned three-layer sheet is
When the main purpose is to capture formaldehyde released from the base material, a first formaldehyde containing a formaldehyde capturing agent is contained.
When the main purpose is to capture and remove formaldehyde that has already been released into the room air from other members or the like, the formaldehyde capture agent is not contained. It is necessary to attach the second fibrous layer to the substrate side. In any case, the three-layered sheet must be correctly adhered by judging which side is the side containing the formaldehyde scavenger when attaching the sheet.

However, practically usable formaldehyde scavengers include, for example, dicyandiamide,
Amino compounds such as melamine, urea, barbituric acid,
There are many colorless to pale colors such as amides such as semicarbazide hydrochloride and amino acids such as glutamate, glycine and alanine. Therefore, when the same material as that used for the second fibrous layer is coated or impregnated with a formaldehyde scavenger and used as the first fibrous layer, both sides of the sheet necessarily have substantially the same color. However, there is a problem that it is not always easy to correctly discriminate between the front and back sides in the attaching operation and to attach the sheets correctly.

[0013]

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems of the prior art, and is used for building materials such as wall materials, construction members, fittings, furniture and the like. A formaldehyde-capturing moisture-proof sheet for capturing formaldehyde generated from materials or contained in indoor air to deodorize and detoxify, and to prevent the occurrence of warpage due to moisture absorption and release of the substrate, An object of the present invention is to provide a formaldehyde-trapping moisture-proof sheet that can easily identify the front and back sides and can reliably prevent failure of incorrectly attaching the front and back sides, and a decorative board and an interior member using the same.

[0014]

The formaldehyde-trapping moisture-proof sheet of the present invention comprises a first fibrous layer containing a formaldehyde-trapping agent, a moisture-proof layer, and a second fibrous layer not containing a formaldehyde-trapping agent. In the formaldehyde-capturing moisture-proof sheet sequentially laminated, at least one surface is entirely or partially colored in a color different from the other surface.

[0015] The formaldehyde-trapping moisture-proof sheet of the present invention comprises a first fibrous layer containing a formaldehyde-trapping agent, a moisture-proof layer, and a second fibrous layer containing a formaldehyde-trapping agent. It is characterized by becoming.

[0016] The decorative board of the present invention is a decorative board obtained by subjecting both surfaces of a wooden base material to a formaldehyde capture and moisture proof treatment, wherein at least one surface of the wooden base material is provided with one of the above two types. It is characterized in that a formaldehyde-capturing moisture-proof sheet is attached.

The interior member according to the present invention is an interior member having a flash structure in which a decorative plate having the above-described structure is bonded to the front and back of a frame formed by assembling square members vertically and horizontally.

[0018]

BEST MODE FOR CARRYING OUT THE INVENTION The formaldehyde-trapping moisture-proof sheet of the present invention, as shown in FIG. 1, for example, contains a first fibrous layer 1 containing a formaldehyde-trapping agent, a moisture-proof layer 2, and no formaldehyde-trapping agent. The second fibrous layer 3 is sequentially laminated, and at least one surface thereof, for example, the surface of the first fibrous layer 1 is colored differently from the other surface.

The first fibrous layer 1 containing a formaldehyde scavenger is formed by internally adding, impregnating or applying a formaldehyde scavenger to a fibrous sheet such as paper or woven or nonwoven fabric. Can be used. The reason why the fiber type is selected is that the adhesiveness of the vinyl acetate emulsion adhesive, which is frequently used in the construction industry and the wood processing industry, is taken into consideration.

In addition, for example, in a member having a flash structure, a considerable strength is required for a bonding portion with a frame center, and therefore, it is most preferable to use a sheet-to-sheet reinforced paper excellent in sheet-to-sheet strength. Regarding the method of incorporating the formaldehyde scavenger, the internal addition method is preferable for the impregnation method or the coating method which is performed in a later step, since the production in a small amount for a specific use is costly.

As the formaldehyde scavenger, any substance can be used as long as it has a function of physically or chemically reacting with formaldehyde to change to a harmless and odorless state. In particular, amino compounds such as dicyandiamide and melamine can be used. Amides such as urea, barbituric acid, semicarbazide hydrochloride, glutamate, glycine,
It is preferable to use nitrogen-containing compounds such as amino acids such as alanine.

The thickness of the first fibrous layer 1 containing a formaldehyde scavenger is not particularly limited. For example, in the case of paper, the basis weight is preferably in the range of 20 to 100 g / m ² , and particularly preferably ^{20 to} 50 g / m ^2. m ² range,
It is the most preferable in terms of sticking work and cost.

The moisture-proof layer 2 prevents moisture in the outside air from passing through the formaldehyde-trapping moisture-proof sheet and entering the substrate, or conversely, moisture in the substrate from passing through the formaldehyde-trapping moisture-proof sheet and being lost to the outside air. This is provided in order to prevent the occurrence of water and keep the water content in the base material constant regardless of the temperature and humidity conditions of the outside air.

Examples of the material of the moisture-proof layer 2 include synthetic resins such as polyethylene, polypropylene, polyvinyl chloride, polyvinylidene chloride, polyethylene terephthalate, polyethylene naphthalate, polycarbonate and polytetrafluoroethylene, metals such as aluminum and stainless steel, and glass. Any material can be used as long as it has a lower moisture permeability than wood or paper, such as inorganic materials such as silicon oxide, silicon nitride, and magnesium oxide, or resin-impregnated paper and resin-impregnated cloth. However, it is preferable to use a synthetic resin or a metal foil from the viewpoint of sticking workability to a base material and followability to corners and curved surfaces.

In particular, considering the convenience of disposal after use of the member, it is most preferable to use a combustible synthetic resin that can be incinerated together with the wood-based material constituting the substrate, the frame center, and the like. Specifically, it is preferable to use materials that do not generate harmful gases such as hydrogen chloride even when incinerated, such as polyolefin resins such as polyethylene and polypropylene, and polyester resins such as polyethylene terephthalate.

The thickness of the moisture-proof layer 2 is not particularly limited, but is preferably about 100 μm or less from the viewpoint of workability. The lower limit of the thickness is determined by the moisture permeability, moisture permeability but is prima facie effect if largely 50g / m ² · 24hour less obtained, considering the changes due to many years of time, or less 20g / m ² · 24hour 5g / m ² · 24h, especially in those used in harsh environments exposed to the weather and the humidity of the bathroom, etc.
our or less.

Second form containing no formaldehyde scavenger
The material of the fibrous layer 3 is similar to that of the first fibrous layer 1,
It can be arbitrarily selected from fibrous sheet bodies such as paper, woven cloth, and non-woven cloth, and may be the same as or different from that used for the first fibrous layer 1. From the viewpoint, it is most preferable to use the paper between sheets. Its thickness is preferably in a range of basis weight 20 to 100 g / m ^2, most preferred is a range among them of 20 to 50 g / m ^2.

The above-mentioned first fibrous layer 1 containing the formaldehyde scavenger, the moisture-proof layer 2, and the second fibrous layer 3 not containing the formaldehyde scavenger are usually laminated via an adhesive. However, the adhesive may be any known adhesive such as a vinyl acetate adhesive, a urethane adhesive, an epoxy adhesive, an acrylic adhesive, a synthetic rubber adhesive, and a cellulose adhesive. Agents can be used. Further, it is also possible to directly laminate the moisture-proof layer 4 without using an adhesive by a solution coating method, a melt coating method, a heat fusion method, an ultrasonic fusion method, a vacuum film forming method or the like.

In particular, when a thermoplastic resin such as polyethylene is used as the moisture-proof layer 2, the first fibrous layer 1 containing a formaldehyde scavenger and the second fibrous layer 3 not containing a formaldehyde scavenger are used. According to the method of extruding the molten resin for forming the moisture-proof layer 2 and bonding the two fibrous layers at the same time as forming the moisture-proof layer 2, a highly efficient production can be achieved. The impregnation or application of the formaldehyde scavenger to the first fibrous layer 1 may be performed after lamination with the moisture-proof layer 2 and the second fibrous layer 3.

The formaldehyde-capturing moisture-proof sheet of the present invention is characterized in that at least one surface is colored differently from the other surface for the purpose of facilitating the discrimination between the front and back surfaces. The surface to be colored may be the surface of the first fibrous layer 1 containing formaldehyde, or the surface of the second fibrous layer 2 not containing formaldehyde on the opposite side. The surfaces on both sides may be colored differently from each other.

The coloring may be performed in a uniform color over the entire surface, for example, in a pattern such as a stripe, a grid, or a dot, or in an arrangement of arbitrary figures such as characters, symbols, and designs. There may be. The color is not particularly limited, but generally, for white of paper or the like on the other side, brown or yellow, etc.
It is considered appropriate to adopt a color close to the wood base material.

Examples of the coloring method include a method of adding a coloring agent such as a pigment at the time of papermaking, a method of varying the raw material and bleaching degree of paper or the like, a method of printing before or after lamination with the moisture-proof layer 2 or the like. Any method such as a method of coating or impregnating can be used. Among them, a method using a combination of fibrous layers of paper or the like having different colors depending on the raw material or the difference in bleaching degree, or when applying or impregnating the formaldehyde scavenger to the fibrous layer 1, the coating liquid or impregnation is used. According to the method in which the colorant is contained in the liquid, compared with the case of the conventional three-layered formaldehyde-capturing moisture-proof sheet, the number of manufacturing steps is not increased, and the step of including the formaldehyde-capturing agent is also included. This is the most preferable because an accident or the like in which the coated surface is mistaken between the two steps of the coloring step can be prevented.

In addition, as shown in FIG. 2, for example, a first fibrous layer 1 containing a formaldehyde scavenger, a moisture-proof layer 2, and a second fibrous layer 4 containing a formaldehyde scavenger, The object of the present invention can also be achieved by adopting a configuration in which the layers are sequentially stacked. In this case, similarly to the above example, one or both surfaces may be colored completely or partially, but the object of the present invention can be sufficiently achieved without coloring. .

As described above, the structure in which the fibrous layers on both sides of the moisture-proof layer 2 contain a formaldehyde scavenger is the most preferable from the viewpoint of preventing erroneous sticking, but is more preferable from the viewpoint of cost. It can not be said. However, excellent effects are obtained for both the purpose of capturing formaldehyde emitted from wood-based substrates and the capture of formaldehyde in indoor air, so applications that require both of these effects Is preferred.

For applications where the quantitative requirements of the formaldehyde scavenging effect for the two purposes are different, the moisture-proof layer 2
By changing the thickness of the fibrous layers on the front and back and the content of the formaldehyde scavenger, the cost can be reduced while maintaining the required effects. In such a case, in order to prevent erroneous sticking, it is preferable that at least one surface is entirely or partially colored in a color different from the other surface.

The formaldehyde-capturing moisture-proof sheet of the present invention is usually used for an invisible surface such as an inner surface of a plate material constituting the front and back surfaces of a flash panel, and a back surface of a wall material, a floor material and a ceiling material. It is. In order to reliably achieve the formaldehyde trapping effect and the effect of preventing warpage due to moisture absorption and desorption, it is most preferable to attach a formaldehyde trapping moisture-proof sheet to both front and back surfaces of a plate material such as a wooden base material. For example, it is conceivable to attach the formaldehyde-trapping moisture-proof sheet of the present invention to both surfaces of a wooden base material and further apply a desired design to one surface thereof by attaching or painting an arbitrary decorative sheet.

However, on the surface where design is required, instead of using the formaldehyde-capturing moisture-proof sheet of the present invention, formaldehyde-capturing moisture-proof treatment can be performed by another method. For example, the present inventors have already filed Japanese Patent Application No. 8-15898.
The method of attaching a decorative sheet having a desired design to the formaldehyde-trapping layer and the moisture-proof layer, which is proposed in the above item, can also be used. In this case, since the decorative sheet has a predetermined design on the surface side,
There is no danger of sticking the front and back side by mistake.

The decorative sheet having the design to be stuck on the front side preferably has at least a moisture-proof property for preventing warpage, but the formaldehyde-trapping effect can be obtained only by the formaldehyde-trapping moisture-proof sheet stuck to the back side.
It is not necessary for the decorative sheet to have formaldehyde scavenging capability, as it can be achieved to a large extent.

However, if the decorative sheet is made of a formaldehyde-permeable material, formaldehyde is diffused from the front side of the decorative sheet, and the formaldehyde capturing efficiency of the formaldehyde capturing moisture-proof sheet on the back side is reduced. As the decorative sheet, it is preferable to use a sheet having at least low formaldehyde permeability. Specifically, for example, it is preferable to use a decorative sheet containing at least a resin-impregnated paper, a synthetic resin layer, a metal foil layer, and the like.

The decorative board having the above-described structure is attached to the front and back of a frame formed by assembling squares vertically and horizontally to form a flash structure, thereby completing the interior member of the present invention. Since the interior and exterior members are subjected to a moisture proof treatment and a formaldehyde trapping treatment on both the inside and outside of the plate material on both front and back sides, there is no warping or distortion due to moisture absorption and desorption, and further, unpleasant odor and health due to formaldehyde It is an excellent material that can prevent damage.

For applications where both sides are visible, such as indoor doors, it is preferable that a desired design is provided on both sides. Preferably used on both sides of the heart. On the other hand, for applications in which the back side is not normally visible, such as a push-in door or a storage door, a plate material without a design but formed only by formaldehyde capture and moisture proofing can be used on the back side of the frame core.

[0042]

【Example】

<Example 1> ^On a white sheet-reinforced paper having a basis weight of 30 g / m ² ,
An aqueous solution containing 25% by weight of sodium glutamate, 5% by weight of dicyandiamide, 0.5% by weight of a red water-soluble dye, and 1% by weight of a yellow water-soluble dye was impregnated, dehydrated, dried, and colored orange. A fibrous layer containing a formaldehyde scavenger having a basis weight of 35 g / m ² was obtained.

The same white inter-sheet reinforced paper having a basis weight of 30 g / m ² was used as the second fibrous layer, and the extrusion lamination was performed between the second fibrous layer and the fibrous layer containing the formaldehyde scavenger. According to the method, a polyethylene resin layer was provided to a thickness of 25 μm to form a moisture-proof layer, thereby producing a formaldehyde-trapping moisture-proof sheet of the present invention.

<Example 2> An inter-sheet reinforced paper having a basis weight of 30 g / m ² was impregnated with an aqueous solution in which 25% by weight of sodium glutamate and 5% by weight of dicyandiamide were respectively dissolved, dehydrated, dried, and dried. In between, the polyethylene resin layer was formed to a thickness of 25 μm by an extrusion lamination method.
m to form a formaldehyde-trapping moisture-proof sheet of the present invention.

[0045] unbleached kraft paper <Example 3> basis weight of 50 g / m ^2, dried and impregnated with 20 wt% aqueous solution of melamine, dried, this and having a basis weight of 50 g / m ² bleached kraft paper and the In between, a polyethylene resin layer having a thickness of 25 μm was provided by an extrusion lamination method to produce a formaldehyde capturing moisture-proof sheet of the present invention.

Example 4 A lattice pattern and a trade name were repeatedly printed with a brown ink on the surface of a sheet-to-paper reinforced paper having a basis weight of 30 g / m ² , and this was impregnated with an aqueous sodium glutamate solution.
After dehydration, a polyethylene resin layer having a thickness of 25 μm was provided between the sheet and an unprinted / unimpregnated same sheet-reinforced paper by an extrusion lamination method to prepare a formaldehyde capturing moisture-proof sheet of the present invention.

[0047]

The formaldehyde-trapping moisture-proof sheet of the present invention comprises a first fibrous layer containing a formaldehyde-trapping agent, a moisture-proof layer, and a second fibrous layer not containing a formaldehyde-trapping agent. In the formaldehyde-capturing moisture-proof sheet, at least one surface has a color different from that of the other surface, which is entirely or partially colored.
This has the advantage that the front and back of the formaldehyde capturing moisture-proof sheet can be easily distinguished, and the sheet can be correctly and reliably adhered without erroneous pasting failure.

The formaldehyde-capturing moisture-proof sheet of the present invention comprises a first fibrous layer containing a formaldehyde capturing agent, a moisture-proof layer, and a second fibrous layer containing formaldehyde, which are sequentially laminated. Thereby, it is possible to obtain the desired formaldehyde trapping effect and moisture-proof effect even if the front and back are erroneously attached, and furthermore, the trapping of formaldehyde emitted from the wood-based substrate and the trapping of formaldehyde in indoor air, It has an excellent advantage that it can be suitably used for applications requiring both effects.

Since the decorative board of the present invention is subjected to formaldehyde capture and moisture proof treatment on both surfaces of the wooden base, the wooden base does not warp due to moisture absorption and desorption. Can prevent unpleasant odors and health hazards due to the emission of formaldehyde from the product.Moreover, by adopting the formaldehyde-capturing moisture-proof sheet having the above-described configuration on at least one side thereof, the front and back of the formaldehyde capturing moisture-proof sheet can be easily formed. Since the discrimination can be made, there is no possibility that a defective product whose desired performance cannot be obtained due to erroneous attachment of the front and back sides does not occur, and there is an excellent advantage that the production can be reliably performed with good workability.

The interior member according to the present invention has a structure in which the decorative plate having the above-described structure is attached to the front and back of a frame formed by assembling squares vertically and horizontally, thereby absorbing and releasing the plate material on the front and back of the frame. It does not cause any warpage due to heat, and can prevent unpleasant odors and health hazards due to the emission of formaldehyde from the wood-based base material. This method has an excellent advantage that an inferior product that cannot be obtained does not occur, and it can be manufactured with good workability.

[Brief description of the drawings]

FIG. 1 is a side sectional view showing an embodiment of a formaldehyde capturing moisture-proof sheet of the present invention.

FIG. 2 is a side sectional view showing an embodiment of a formaldehyde capturing moisture-proof sheet of the present invention.

[Explanation of symbols]

1) First fibrous layer containing formaldehyde scavenger 2) Moisture barrier 3) Second fibrous layer not containing formaldehyde scavenger 4) Second fibrous layer containing formaldehyde scavenger

──────────────────────────────────────────────────の Continued on front page (51) Int.Cl. ⁶ Identification code FI B32B 33/00 B32B 33/00 E04B 2/00 E04C 2/46 Z

Claims (4)

[Claims] 1. A formaldehyde scavenging moisture-proof sheet comprising a first fibrous layer containing a formaldehyde scavenger, a moisture-proof layer, and a second fibrous layer not containing a formaldehyde scavenger, which are laminated in this order. A formaldehyde-capturing moisture-proof sheet characterized in that one surface is entirely or partially colored in a color different from the other surface. 2. A formaldehyde scavenger comprising a first fibrous layer containing a formaldehyde scavenger, a moisture-proof layer, and a second fibrous layer containing a formaldehyde scavenger, which are sequentially laminated. Moisture proof sheet. 3. A decorative board in which both surfaces of a wooden substrate are subjected to a moisture-proof treatment, wherein the formaldehyde-capturing moisture-proof sheet according to claim 1 or 2 is attached to at least one surface of the wooden substrate. A decorative plate characterized by comprising: 4. An interior member having a flash structure, wherein the decorative panel according to claim 3 is attached to the front and back of a frame center formed by assembling square members vertically and horizontally.