JP2017110320A - Foam wall paper - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a foam wall paper capable of effectively adsorbing formaldehyde in atmosphere.SOLUTION: A foam resin layer 2 and a surface layer are formed in this order on a substrate sheet 1 of a foam wall paper 10. The substrate sheet 1 contains a formaldehyde adsorbent and multiple small holes 7 with depth from the surface layer to a midway position of the foam resin layer. The surface layer is formed by, for example, one of or combined layer of a coat layer, a pattern layer and a surface protective layer.SELECTED DRAWING: Figure 1

Description

  The present invention relates to wallpaper. In particular, the present invention relates to a foam wallpaper having a function of adsorbing formaldehyde.

In recent years, due to the rise in timber prices due to the depletion of natural timber and the increase in forest protection activities related to global environmental problems, as a material that is less wasteful and cheaper than the so-called solid wood of natural timber, Various woody base materials obtained by artificially processing natural wood, such as laminated timber, particle board, hard board, and medium density fiber plate (MDF), are increasingly used. .
These artificial wood materials are highly uniform in terms of performance, stable in dimensional accuracy and strength, and excellent in workability. It can be said that it has supported.

Such a wood-based substrate is made by cutting or decomposing wood into thin plates, small pieces, or fibers, and connecting them with an adhesive to reconstruct them. Therefore, it is attractive that it is relatively inexpensive and stable in terms of price. Further, as an adhesive, for example, an adhesive containing formaldehyde such as urea or phenol is often used from the viewpoints of adhesive strength to wood fibers, adhesion workability, and cost.
However, in actual production, there are many cases where formaldehyde is excessively added for the purpose of improving the bonding strength and bonding speed, and the formaldehyde is volatilized out of the adhesive by the heat treatment for curing the adhesive. In some cases, it may remain in the wood fiber or the piece of wood, and it is naturally assumed that formaldehyde remains on the wood base material.

The building materials and furniture manufactured in this way are considered harmful to the human body, and formaldehyde gas, which has a special unpleasant odor called formalin odor, is diffused. It has been pointed out that there is a risk of not only allergic symptoms but also health problems. Formaldehyde is one of the causes of the so-called sick house syndrome, which has been attracting attention in recent years.
As a solution to this problem, for example, in Patent Document 1, wood grain is printed on paper impregnated with a formaldehyde adsorbent and pasted on the surface of the wooden base material, thereby adsorbing and removing the diffused formaldehyde of the wooden base material. Although a method has been proposed, it has only been used for decorative plywood.

Alternatively, Patent Document 2 proposes to provide a resin layer containing a formaldehyde adsorbent on a base sheet, but the design is limited and the effect is limited to the range where the surface resin layer contacts. It was.
Under such circumstances, interior materials that can efficiently adsorb formaldehyde without impairing design properties and surface properties, particularly wallpaper that can be used in large areas such as walls and ceilings, have been demanded. It was.

Japanese Patent Publication No.52-134 Japanese Patent Laid-Open No. 10-258495

  This invention is made | formed in view of the above points, and it aims at providing the foam wallpaper which can adsorb | suck the formaldehyde in atmosphere effectively.

In order to solve the problem, in the foamed wallpaper of one embodiment of the present invention, a foamed resin layer and a surface layer are formed in this order on a base sheet, and the base sheet contains a formaldehyde adsorbent, from the surface layer. A plurality of small holes having a depth up to a middle position of the foamed resin layer are provided.
The surface layer is a layer formed of, for example, any one of a coat layer, a pattern layer, and a surface protective layer, or a combination thereof.

According to the aspect of the present invention, it is possible to provide a foamed wallpaper having a predetermined contamination resistance while effectively adsorbing formaldehyde in the atmosphere.
In addition, since the formaldehyde adsorbent is provided on the back side of the foam wallpaper, it is possible to absorb formaldehyde from the base material to which the foam wallpaper is attached.

It is an example of the foam wallpaper based on embodiment based on this invention, Comprising: It is a partial cross-section schematic diagram of the state bonded together to the base material board.

Embodiments of the present invention will be described below with reference to the drawings.
As shown in FIG. 1, the foamed wallpaper 10 of the present embodiment has a foamed resin layer 2 formed on a base sheet 1, and a coat layer 3, a pattern layer 4, and a surface protective layer 5 are provided in this order. Yes. The coat layer 3, the pattern layer 4, and the surface protective layer 5 form a surface layer. When the surface layer is not necessary, any one layer or a plurality of layers of the coat layer 3, the pattern layer 4, and the surface protective layer 5 can be omitted.
Moreover, in this embodiment, after providing the surface layer in the foamed resin layer 2, it heat-foams, and the case where the three-dimensional design property is provided with respect to the wallpaper 10 by providing an unevenness | corrugation by the embossing process from the surface is illustrated. ing.

  Here, FIG. 1 illustrates a state in which the foamed resin layer 2 is bonded to a gypsum board that is a base plate 12 via an adhesive layer 11. The base plate 12 to which the foam wallpaper 10 is attached is obtained by artificially processing natural wood such as plywood, laminated wood, particle board, hard board, medium density fiber plate (MDF) in addition to gypsum board. Various woody base materials to be used can be used as the base plate. It is also possible to install it directly on the wall or ceiling surface at the construction site. The gypsum board may be a gypsum board having a formaldehyde adsorption function. A known means may be applied to impart the formaldehyde adsorption function to the gypsum board.

<Small hole>
The wallpaper 10 has a large number of small holes 7. Each small hole 7 is a hole having a depth from the surface of the foam wallpaper 10 to the midway position of the foam resin layer 2. The depth of the small holes 7 is, for example, in the range of 50% to 90% of the thickness of the foamed resin layer 2.
The small holes 7 are provided in a number of, for example, 4 to 12 per 1 cm ² , and each small hole 7 has an opening area at the surface layer position of 100 μm to 1000 μm in diameter, preferably 200 μm to 500 μm in diameter. Have been adjusted so that. When the opening cross-sectional shape of the small hole 7 is not a circular shape, it is a value converted into the area of a circle.

The small hole 7 is formed by piercing a needle, for example. As the needle to be used, a needle having a diameter of 100 μm or more and 1000 μm or less may be used. As shown in FIG. 1, which is a schematic diagram, the small hole 7 opened by the needle usually has the most opening on the surface of the wallpaper and tends to have a smaller opening cross section toward the tip. For this reason, the small hole 7 is prescribed | regulated by the opening area in the surface layer position estimated to be substantially equal to the diameter of the needle.
By adjusting the amount per unit area of the plurality of small holes 7, the opening area of the small holes 7, and the midway position in the thickness direction of the foamed resin layer ² , the moisture permeability of the foamed resin layer is 500 g / m ² · The adjustment is made so that it is not less than day and not more than 1500 g / m ² · day.

By setting the water vapor transmission rate to 500 g / m ² · day or more, formaldehyde in the base sheet 1 having a formaldehyde adsorption function can be more effectively absorbed.
Moreover, since the small hole 7 does not penetrate the foamed resin layer, it is possible to impart stain resistance. In particular, it has been confirmed that the wall paper can have a predetermined contamination resistance if it is 1500 g / m ² · day or less.
Here, the moisture permeability in this specification is a value calculated by measurement at a temperature of 40 ° C. and a humidity of 90% in accordance with JIS Z 0208 “Method of moisture permeability test for moisture-proof packaging materials (cup method)”.

<Base material sheet 1>
As the base material sheet 1, in addition to a general paper base material, wallpaper base paper can be used. Wallpaper base paper is not particularly limited, may be suitably selected from those sold as wallpaper base paper from paper manufacturers, it can be used as the basis weight of ^{30g / m 2 ~150g / m 2} .
The base sheet 1 of this embodiment contains a formaldehyde adsorbent.
For example, the formaldehyde adsorbent is contained in the base sheet 1 by applying and drying a formaldehyde adsorbent aqueous solution on the surface of the base sheet 1.

Formaldehyde adsorbent aqueous solution is an aqueous solution containing one or more organic substances of urea, ethylene urea, hydrazide compounds, alcohol amine compounds, azole compounds, and azine compounds as formaldehyde adsorbents. Formaldehyde adsorbent is provided on the base sheet 1.
The concentration of the formaldehyde adsorbent in the aqueous formaldehyde adsorbent solution is 30% by mass or more, preferably 50% by mass or more. The higher the concentration, the better the formaldehyde adsorption.
In order to secure a predetermined adhesiveness or more, an adhesive primer layer may be provided between the base sheet 1 and the foamed resin layer 2. In this case, the formaldehyde adsorbent aqueous solution may be applied to the base sheet 1 itself, and the formaldehyde adsorbent may be added to the primer layer. In this case, the amount of the adsorbent is 0.1 to 10 parts by mass with respect to 100 parts by mass of the primer in the primer layer, for example.

<Foamed resin layer>
As the resin used for the foamed resin layer 2, a vinyl chloride resin, an ethylene vinyl acetate copolymer (EVA) resin, an acrylic resin, a polyolefin resin, or the like can be used. For the formation of the resin layer, a suitable one can be selected from a coating method, a method using an extruder, a method using a calendar machine, and the like.
If the resin used for the foamed resin layer 2 is an emulsion type resin such as vinyl chloride sol, acrylic, or ethylene vinyl acetate copolymer, it can be applied using a coating machine such as a die coater or a comma coater. Is possible.

Recently, there are growing voices of concern about the impact on the global environment, but when considering these, it is possible to use ethylene vinyl acetate copolymer resins, acrylic resins, polyolefin resins, etc. other than vinyl chloride resins. desirable.
As the foaming agent contained in the foamed resin layer 2, a known foaming agent may be employed, but a pyrolytic foaming agent is preferably used. For example, azodicarbonamide (ADCA) type blowing agent, oxybisbenzenesulfonyl hydrazide (OBSH) type blowing agent and the like can be exemplified. Among these, ADCA-based foaming agents are preferable because they have high film-forming properties because of their high thermal decomposition temperatures and are less likely to cause abnormal foaming during extrusion film formation.

The content of the pyrolytic foaming agent can be appropriately set according to the type of foaming agent, the expansion ratio, and the like. The foaming agent is preferably about 0.01 to 20 parts by mass and more preferably about 0.1 to 10 parts by mass with respect to 100 parts by mass of the resin component.
The foaming agent foams by heating the wallpaper 10 and forms voids in the foamed resin layer 2.
Here, the foamed resin layer 2 may be blended with a formaldehyde adsorbent. The formaldehyde adsorbent to be blended must contain one or more organic substances of urea, ethylene urea, hydrazide compound, alcohol amine compound, azole compound, and azine compound.

The blending amount of the formaldehyde adsorbent contains 0.1 to 10 parts by mass of the adsorbent with respect to 100 parts by mass of the resin of the foamed resin layer 2, without causing any trouble in the manufacturing process of wallpaper. Moreover, the effect of formaldehyde adsorption is preferably exhibited without impairing the design properties.
The foamed resin layer 2 can be blended with any one or more inorganic substances of natural zeolite, acidic clay, diatomaceous earth, synthetic zeolite, artificial zeolite, activated carbon, titanium oxide, and phosphate. By containing the inorganic substance, adsorption of formaldehyde in the foamed resin layer 2 can be further promoted.

For example, zeolite has silicon oxide and aluminum oxide as the main components and has a porous structure, so that it not only has its own adsorption function but also helps to adsorb the formaldehyde adsorbent of the compounded organic compound. . The same applies to acid clay, diatomaceous earth, activated carbon and the like, and can be appropriately selected in consideration of adsorption performance and price.
Various additives may be added to the foamed resin layer 2. For example, antioxidants, inorganic fillers, pigments and foam stabilizers, zinc compounds, crosslinking agents, surface treatment agents, fluorescent brighteners, fungicides, lubricants, and the like can be used as additives.

<Surface>
If necessary, the pattern layer 4 can be provided on the surface of the foamed resin layer 2 for the purpose of improving the design. The picture layer 4 can be provided by a known printing method, and although not particularly limited, for example, a gravure printing method or the like can be used.
Printing is performed before the heat foaming after forming the foamed resin layer 2 and providing the coating layer 3 and the surface protective layer 5 as required in addition to the pattern layer 4. The ink used for printing is not particularly limited, but can be appropriately selected according to the printing method and considering the ink adhesion and light resistance.

The coat layer 3 is provided for the purpose of strengthening the adhesiveness of the ink between the foamed resin layer 2 and the picture layer 4 or for the purpose of strengthening the adhesiveness between the foamed resin layer 2 and the surface protective layer 5. Therefore, when it is not necessary to provide the pattern layer 4 and the surface protective layer 5, it may be omitted.
The surface protective layer 5 is provided for the purpose of protecting the surface of the wallpaper, such as improving the stain resistance. However, an appropriate layer may be used depending on the required quality. For example, the surface protective layer 5 may have an object such as improved peel resistance or surface hardness. According to the purpose, the type of coating agent can be appropriately selected and the formulation can be designed.

<Action and others>
The wallpaper 10 has the formaldehyde 6 in the surrounding atmosphere effectively penetrated into the foamed resin layer 2 through the small holes 7, and the formaldehyde 6 that has entered the foamed resin layer 2 through the small holes 7 is effectively foamed resin. It diffuses into layer 2.
Furthermore, as indicated by an arrow in FIG. 1, the formaldehyde 6 that has entered through the small holes 7 passes through the foamed resin layer 2 and reaches the base sheet 1. And the capture | acquisition and adsorption | suction of formaldehyde are performed with the base material sheet 1 which has a formaldehyde adhesion function. In this way, the adsorption of formaldehyde is effectively performed through the small holes 7.

Here, when only the incorporation of formaldehyde into the base sheet 1 is considered, there is no problem even if the moisture permeability of the foamed resin layer is high, but if the moisture permeability becomes high, there is a risk of affecting the stain resistance such as weather resistance. There is. From this viewpoint, it is preferable to suppress the moisture permeability of the foamed resin layer to 1500 g / m ² · day or less.
Further, if the diameter of the small hole 7 is large, the air permeability becomes high, and the efficiency of capturing and adsorbing formaldehyde increases. However, it is also important not to impair the design properties, and considering the range in which the contamination resistance of the surface is not impaired, the opening in the surface layer of the small hole 7 is preferably in the range of 100 μm to 1000 μm in diameter, and 200 μm to 500 μm in diameter The following ranges are more preferable.

When the number per unit area is too large, the small holes are too close to each other and the same as when the diameter of the small hole 7 is increased, the number of small holes 7 is, for example, 4 per 1 cm ^2. A number from 12 to 12 is preferred.
Thus, in the foam wallpaper of this embodiment, it is possible to provide a foam wallpaper having a predetermined contamination resistance while effectively adsorbing formaldehyde in the atmosphere.
In addition, since the formaldehyde adsorbent is provided on the back side of the foam wallpaper, it is possible to absorb formaldehyde from the base material to which the foam wallpaper is attached.

Hereinafter, the present invention will be described more specifically with reference to examples. However, the present invention is not limited to these examples.
<Sample 1>
Sample 1 was prepared with the following material configuration and procedure.
A foamed resin was laminated on the substrate sheet 1WK685 (manufactured by KJ special paper), and a texture-like pattern layer was provided on the foamed resin, which was heated and foamed. Subsequently, using a needle having a diameter of 300 μm from the pattern layer side, a needle hole having a density of 6/1 cm ² was made up to about 80% of the thickness of the foamed resin layer, and a foamed wallpaper of Sample 1 was obtained.

<Sample 2>
Sample 2 was prepared with the following material composition and procedure.
A 10 mass% formaldehyde adsorbent aqueous solution was applied on a base sheet 1WK685 (manufactured by KJ Special Paper), a foamed resin was laminated thereon, a texture-like pattern layer was provided thereon, and foamed by heating. Subsequently, using a needle having a diameter of 300 μm from the pattern layer side, needle holes having a density of 6/1 cm ² were made up to about 80% of the thickness of the foamed resin layer, and a foamed wallpaper of Sample 2 was obtained.
<Sample 3>
Sample 3 was prepared with the following material composition and procedure.
An aqueous solution of formaldehyde adsorbent with a concentration of 30% by mass was applied onto a base sheet 1WK685 (manufactured by KJ Special Paper), a foamed resin was laminated thereon, a texture-like pattern layer was provided thereon, and heat foamed. Subsequently, using a needle having a diameter of 300 μm from the pattern layer side, needle holes with a density of 6/1 cm ² were made up to about 80% of the thickness of the foamed resin layer, and a foamed wallpaper of Sample 3 was obtained.

<Sample 4>
Sample 4 was prepared with the following material composition and procedure.
A 40 mass% formaldehyde adsorbent aqueous solution was applied onto a base sheet 1WK685 (manufactured by KJ Special Paper), a foamed resin was laminated thereon, a texture-like pattern layer was provided thereon, and heat foamed. Subsequently, using a needle having a diameter of 300 μm from the pattern layer side, needle holes with a density of 6/1 cm ² were made up to about 80% of the thickness of the foamed resin layer, and a foamed wallpaper of Sample 4 was obtained.
<Sample 5>
Sample 5 was prepared with the following material configuration and procedure.
A 50 mass% formaldehyde adsorbent aqueous solution was applied onto a substrate sheet 1WK685 (manufactured by KJ Special Paper), a foamed resin was laminated thereon, a textured pattern layer was provided thereon, and heat foamed. Subsequently, using a needle having a diameter of 300 μm from the pattern layer side, a needle hole with a density of 6/1 cm ² was drilled to about 80% of the thickness of the foamed resin layer, and a foamed wallpaper of Sample 5 was obtained.

<Sample 6>
Sample 6 was prepared with the following material configuration and procedure.
A 60 mass% formaldehyde adsorbent aqueous solution was applied onto a substrate sheet 1WK685 (manufactured by KJ Special Paper), a foamed resin was laminated thereon, a texture-like pattern layer was provided thereon, and heat foamed. Subsequently, using a needle having a diameter of 300 μm from the pattern layer side, a needle hole with a density of 6/1 cm ² was drilled to about 80% of the thickness of the foamed resin layer, and a foamed wallpaper of Sample 6 was obtained.
<Sample 7>
Sample 7 was prepared with the following material configuration and procedure.
A 50 mass% formaldehyde adsorbent aqueous solution was applied onto a substrate sheet 1WK685 (manufactured by KJ Special Paper), a foamed resin was laminated thereon, a textured pattern layer was provided thereon, and heat foamed. Subsequently, using a needle having a diameter of 300 μm from the pattern layer side, a needle hole with a density of 1 piece / 1 cm ² was made up to about 80% of the thickness of the foamed resin layer, and a foamed wallpaper of Sample 7 was obtained.

<Sample 8>
Sample 8 was prepared with the following material composition and procedure.
A 50 mass% formaldehyde adsorbent aqueous solution was applied onto a substrate sheet 1WK685 (manufactured by KJ Special Paper), a foamed resin was laminated thereon, a textured pattern layer was provided thereon, and heat foamed. Subsequently, using a needle having a diameter of 300 μm from the pattern layer side, a needle hole with a density of 3/1 cm ² was drilled to about 80% of the thickness to obtain a foamed wallpaper of Sample 8.
<Sample 9>
Sample 9 was prepared with the following material composition and procedure.
A 50 mass% formaldehyde adsorbent aqueous solution was applied onto a substrate sheet 1WK685 (manufactured by KJ Special Paper), a foamed resin was laminated thereon, a textured pattern layer was provided thereon, and heat foamed. Subsequently, using a needle having a diameter of 300 μm from the pattern layer side, needle holes with a density of 6/1 cm ² were made up to about 80% of the thickness of the foamed resin layer, and a foamed wallpaper of Sample 9 was obtained.

<Sample 10>
Sample 10 was prepared with the following material configuration and procedure.
A 50 mass% formaldehyde adsorbent aqueous solution was applied onto a substrate sheet 1WK685 (manufactured by KJ Special Paper), a foamed resin was laminated thereon, a textured pattern layer was provided thereon, and heat foamed. Subsequently, using a needle having a diameter of 300 μm from the pattern layer side, needle holes with a density of 10/1 cm ² were made up to about 80% of the thickness of the foamed resin layer, and a foamed wallpaper of Sample 10 was obtained.
<Sample 11>
Sample 11 was prepared with the following material composition and procedure.
A 50 mass% formaldehyde adsorbent aqueous solution was applied onto a substrate sheet 1WK685 (manufactured by KJ Special Paper), a foamed resin was laminated thereon, a textured pattern layer was provided thereon, and heat foamed. Subsequently, using a needle having a diameter of 300 μm from the pattern layer side, needle holes with a density of 15/1 cm ² were made up to about 80% of the thickness of the foamed resin layer, and a foamed wallpaper of Sample 11 was obtained.

<Sample 12>
Sample 12 was prepared with the following material configuration and procedure.
A 50 mass% formaldehyde adsorbent aqueous solution was applied onto a substrate sheet 1WK685 (manufactured by KJ Special Paper), a foamed resin was laminated thereon, a textured pattern layer was provided thereon, and heat foamed. Subsequently, using a needle having a diameter of 300 μm from the pattern layer side, a needle hole having a density of 20/1 cm ² was made up to about 80% of the thickness of the foamed resin layer, and a foamed wallpaper of Sample 12 was obtained.
The foamed wallpaper of Sample 1 to Sample 9 was evaluated using the following test items, evaluation methods, and evaluation criteria.

<Formaldehyde adsorption test>
The evaluation method is as follows.
(1) An unglazed plate with a hole is disposed in a constricted portion of a desiccator (inner diameter: 24 cm) having a volume of 1.6 l.
(2) A glass container containing 300 ml of distilled water is placed under the unglazed plate.
(3) A 15 cm × 15 cm sample is placed on the unglazed plate, and a polyethylene container in which a formaldehyde generation source (solution) is placed is placed thereon.
At this time, the concentration of the formaldehyde generation source is 0.38 mg / ml, and the solution amount is 25 ml.
(4) Collect distilled water after 24 hours.
(5) The formaldehyde concentration of distilled water is measured according to the method of JIS A6921. Distilled water collected from a desiccator containing only a formaldehyde source is 1.5 mg / ml.

The concentration of distilled water collected from the desiccator containing the test piece was measured and evaluated according to the following evaluation criteria.
The evaluation criteria are as follows.
0.0 to 0.2 mg / ml: ○
0.3 to 0.5 mg / ml: Δ
0.6 to 1.5 mg / ml: x

<Contamination test>
The evaluation method is as follows.
1) It was conducted with reference to the standard “Smudge prevention wallpaper performance regulations” established by the Wall Wholesaler Council.
2) Collect a test piece of A4 size and apply the following contaminants to the test piece.
Pollutants: aqueous pens, crayons, coffee, soy sauce.
3) After leaving this for 24 hours,
Wipe off coffee and soy sauce with water, and wipe off water-based sign pens and crayons with water or neutral detergent.
4) Visually compare the contaminated part with the uncontaminated part.
The evaluation criteria are as follows.
Dirt falls: ○
Dirt is not removed: ×

<Construction test>
The evaluation method is as follows.
A test piece of the same size is applied to a 150 mm square plaster board with construction glue.
Visually observe the presence or absence of glue loss after construction.
The evaluation criteria are as follows.
No glue removal from the through hole: ○
There is paste removal from the through hole: ×

<Coating property>
The evaluation method is as follows.
Using an applicator, the foamed resin is applied to the substrate sheet 1, dried, and then visually observed.
The evaluation criteria are as follows.
A uniform film can be formed: ○
Slightly lacking in film uniformity:
Unable to form a uniform film: ×

<Evaluation results>
The evaluation results are shown in Table 1.

As can be seen from Samples 3 to 6 and 9 to 12, the concentration of the adsorbent in the aqueous formaldehyde adsorbent solution provided on the surface of the base sheet 1 is 30% by mass or more, preferably 50% by mass or more. It turns out that it becomes favorable. However, when the number of needle holes is too small as in samples 7 and 8, the air permeability to the base sheet 1 is not ensured.
Here, in the sample 3～6,9, although moisture permeability of the foamed resin layer is in the range of ^{500g / m 2 · day~1500g / m} 2 · day, the moisture permeability of the sample 7 and 8 foamed resin layer It was about 100 g / m ² · day. Samples 11 and 12 had moisture permeability of 3000 g / m ² · day or more. Sample 10 had a water vapor transmission rate of 1500 g / m ² · day.
In addition, since every sample has a needle hole (small hole) in the middle of the foamed resin layer, predetermined contamination resistance is ensured.
Moreover, when there are too many needle holes like the samples 10-12, a water vapor transmission rate becomes too high and workability | operativity worsens.

From the above, it is preferable that the moisture permeability of the foamed resin layer is set to be in the range of ^{500g / m 2 · day~1500g / m} 2 · day. Note that when the moisture permeability of the base sheet is high, the moisture permeability of the entire foam wallpaper in a range of from ^{500g / m 2 · day~1500g / m} 2 · day, the moisture permeability of the foamed resin layer is 500 g / in the range of ^{m 2 · day~1500g / m 2 ·} day.
In addition, if the concentration of the adsorbent in the aqueous formaldehyde adsorbent solution is too high, the coating property is deteriorated, but sufficient concentration is ensured by setting the concentration to 50% by mass or less, preferably 40% by mass or less. You can see that.

DESCRIPTION OF SYMBOLS 1 ... Base material sheet 2 ... Foamed resin layer 3 ... Coat layer (surface layer)
4 ... Pattern layer (surface layer)
5 ... Surface protective layer (surface layer)
6 ... Formaldehyde 7 ... Small hole 10 ... Foam wallpaper 11 ... Adhesive layer 12 ... Gypsum board (base plate)

Claims (6)

A foamed resin layer and a surface layer are formed in this order on the base sheet,
The base sheet contains a formaldehyde adsorbent,
A foamed wallpaper having a plurality of small holes having a depth from the surface layer to a midpoint of the foamed resin layer. Foam wallpaper according to claim 1, wherein the moisture permeability of the foamed resin layer is in the range of ^{500g / m 2 · day~1500g / m} 2 · day.   The foamed wallpaper according to claim 1 or 2, wherein the small holes are openings having a diameter of 20 µm or more and 1000 µm or less when the opening area on the surface layer is converted into a circular shape.   The formaldehyde adsorbent contains one or more organic substances of urea, ethylene urea, hydrazide compounds, alcohol amine compounds, azole compounds, and azine compounds. Foam wallpaper described in any one of the above.   The foamed wallpaper according to any one of claims 1 to 4, wherein the surface layer includes at least one of an undercoat layer, a picture layer, and a surface protective layer.   The foamed resin layer contains one or more inorganic substances selected from natural zeolite, acidic clay, diatomaceous earth, synthetic zeolite, artificial zeolite, activated carbon, titanium oxide, and phosphate. The foam wallpaper as described in any one of Claims 1-5.

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