JP7741520B2 - Flame-retardant wallpaper - Google Patents

Description

The present invention relates to flame-retardant wallpaper made from polyester fibers, pulp, etc.

Conventionally, flame-retardant vinyl chloride resins have been widely used for interior and other building materials. However, vinyl chloride resins have had problems such as generating hydrogen chloride gas when burned and having poor abrasion resistance.

Furthermore, wallpaper made with vinyl chloride resin contains plasticizers to give it flexibility, and there is a problem in that when such wallpaper is exposed to direct sunlight, the plasticizers are released into the air.

Furthermore, wallpaper made with vinyl chloride resin gradually hardens over time, forming gaps where it joins the wall. If moisture gets into these gaps, mold can grow on the underside of the wallpaper, eventually causing the wallpaper to peel off from the wall. Furthermore, when wallpaper made with vinyl chloride resin is applied to a wall, it expands by about 5-15% due to the moisture contained in the adhesive, and then shrinks as it dries, making it difficult to apply to the wall at accurate dimensions.

Therefore, there is a demand for flame-retardant wallpaper that does not use vinyl chloride resin. In particular, there is a strong demand for flame-retardant wallpaper that does not use vinyl chloride resin and can be certified as a "non-combustible material" under Japan's Building Standards Act.

For example, Patent Document 1 discloses such a flame-retardant wallpaper. The wallpaper has a total warp and weft fineness of less than 280 dtex, a cover factor of 1200 or more for either the warp or weft, and a cover factor of 2500 or less for both the warp and weft, a total warp and weft cover factor of 2000 to 4000, a basis weight (mass) of 220 g/ ^m2 or less, and is made of polyester fiber with a single fiber fineness of less than 3 dtex, to which 10 g/m2 or ^less of a halogen-based flame retardant is applied, and a flame-retardant pulp backing paper with a basis weight of 100 g/m2 or ^less containing 10 g/m2 or ^less of a phosphorus-based flame retardant is attached with an ethylene vinyl acetate resin adhesive. The wallpaper conforms to the "non-combustible material" and "semi-non-combustible material" criteria of the Building Standards Act combustion test.

Similarly, Patent Document 2 discloses a flame-retardant wallpaper in which a fabric made of flame-retardant polyester fiber copolymerized with a phosphorus compound and flame-retardant paper are laminated together via a polymer adhesive containing a phosphinic acid derivative, and an organic fluorinated polymer water repellent is attached to the flame-retardant polyester fiber. The wallpaper has good processability, adhesiveness, and stain resistance, does not pollute the indoor environment, and contains highly flame-retardant polyester fiber as a constituent component, which generates little toxic gas when burned.

JP 2006-144173 A Japanese Patent Application Laid-Open No. 2000-178899

However, the wallpapers described in Patent Documents 1 and 2 contain flame retardants such as halogen-based flame retardants, which pose a problem in that harmful substances are generated when burned.

Furthermore, in order for wallpaper to be certified as a "non-combustible material" under the Building Standards Act, it must meet the following conditions (hereinafter referred to as "combustibility conditions") in a flame-retardant performance test (for example, the fire performance test for wallpaper/gypsum board conducted by the Building Materials Testing Center, a general incorporated foundation).
(1) The total heat generation amount for 20 minutes after the start of heating is 8 MJ/ ^m2 or less.
(2) For 20 minutes after heating begins, there are no cracks or holes that penetrate to the back surface and are harmful to fire prevention.
(3) For 20 minutes after the start of heating, the heat generation rate must not exceed 200 kW/ ^m2 for 10 seconds or more.

However, there was a problem in that there was no wallpaper that met the above conditions without containing the flame retardants mentioned above. Wallpaper that meets the flame-retardant conditions is certified as a "non-combustible material" under the Building Standards Act, and can be used without being subject to the interior decoration restrictions stipulated by the Building Standards Act (with the exception of metal panels).

In light of the above circumstances, the present invention aims to provide flame-retardant wallpaper that, compared to wallpaper made with vinyl chloride resin, produces less harmful substances when burned and has flame-retardant properties that qualify it as a "non-combustible material" under the Building Standards Act.

As a result of extensive research and development into the above-mentioned problems, the inventors of the present invention have discovered the following groundbreaking flame-retardant wallpaper.

A first aspect of the present invention for solving the above problems is a flame-retardant wallpaper having a receiving layer impregnated with a paint for the receiving layer on one side of a sheet substrate, characterized in that the sheet substrate is a nonwoven fabric containing 5 to 55% by weight of polyester fiber and 45 to 95% by weight of pulp, the dry weight of the paint for the receiving layer impregnated into the receiving layer is 1 g/m ² to 150 g/m ² , and the paint for the receiving layer contains a synthetic resin as a main component.

Here, polyester fiber refers to fiber made of polyester. Furthermore, "impregnation" refers not only to a state in which the paint has soaked into the minute holes and grooves of the nonwoven fabric, but also to a state in which part of the paint is exposed on the surface of the nonwoven fabric. Furthermore, "dry" refers to a state in which the moisture content of the paint is 13% or less (for example, a state in which the moisture content of a water-based paint is 8% when using the moisture content measurement method for building materials (JIS A 1476:2016)).

According to this first aspect, the receiving layer prevents the paint (pigment) contained in the ink layer formed on the receiving layer (described below) from spreading or bleeding, allowing for vibrant coloring. Furthermore, compared to wallpapers using vinyl chloride resins, pulp can reduce the heat generation rate, so it is possible to provide flame-retardant wallpaper that generates fewer harmful substances when burned and has flame retardancy that allows it to be certified as a "non-combustible material" under the Building Standards Act. Furthermore, flame-retardant wallpaper that is certified as a "non-combustible material" under the Building Standards Act can be used without being subject to interior decoration restrictions (with the exception of metal panels).

A second aspect of the present invention is a functional wallpaper according to the first aspect, characterized in that the sheet substrate contains 5 to 40% by weight of polyester fiber and 60 to 95% by weight of pulp.

According to this second aspect, it is possible to provide flame-retardant wallpaper that emits fewer harmful substances when burned compared to wallpaper made with vinyl chloride resin, and has higher flame retardancy that can be certified as a "non-combustible material" under the Building Standards Act.

A third aspect of the present invention is the flame-retardant wallpaper described in the first aspect, characterized in that the sheet substrate is a nonwoven fabric composed of 20 to 35% by weight of polyester and 65 to 80% by weight of pulp.

According to this third aspect, it is possible to provide flame-retardant wallpaper that emits even less harmful substances when burned than wallpaper made with vinyl chloride resin, and that has even higher flame retardancy and can be certified as a "non-combustible material" under the Building Standards Act.

A fourth aspect of the present invention is the flame-retardant wallpaper described in the first aspect, characterized in that the sheet substrate is a nonwoven fabric containing 10 to 30% by weight of polyester, 60 to 85% by weight of pulp, and 1 to 5% by weight of polyolefin fibers.

Here, polyolefin fibers refer to fibers made of polyolefin.

According to this fourth aspect, it is possible to provide flame-retardant wallpaper that is highly water-resistant and durable, and produces minimal amounts of harmful substances when burned.

A fifth aspect of the present invention is the flame-retardant wallpaper described in the first aspect, characterized in that the crystallinity of the polyester fibers on one surface of the sheet substrate is lower than the crystallinity of the polyester fibers inside the sheet substrate.

According to the fifth aspect, the flexibility of the sheet substrate can be improved without changing the tensile strength or elongation in water. As a result, the embossing described below can be easily formed. Furthermore, there is no need to use a highly pure (low crystallinity) material to manufacture the polyester fiber, and polyester fiber made from recycled resin, for example, can be used.

A sixth aspect of the present invention is the flame-retardant wallpaper according to any one of the first to fifth aspects, characterized in that the synthetic resin is an acrylic resin.

According to this sixth aspect, the strength of the flame-retardant wallpaper can be improved while maintaining its flexibility, compared to other synthetic resins.

The seventh aspect of the present invention is the flame-retardant wallpaper according to the first aspect, characterized in that it has an adhesive layer on the other side of the sheet substrate, the adhesive being a starch-based adhesive whose main component is starch, an adhesive whose main component is acrylic ester, a remoistenable glue that becomes tacky by absorbing moisture, or a hot-melt adhesive, and the thickness of the adhesive layer is 0.01 mm to 5 mm.

According to the seventh aspect, it is possible to provide flame-retardant wallpaper that, including the adhesive layer, reduces the amount of harmful substances emitted even when burned, and has flame retardancy that allows it to be certified as a "non-combustible material" under the Building Standards Act.

An eighth aspect of the present invention is the flame-retardant wallpaper according to the seventh aspect, characterized in that a colored layer is provided between the other surface of the sheet substrate and the adhesive layer.
According to the eighth aspect, the provision of a colored layer can prevent the color of the wall to which the flame-retardant wallpaper is attached from being visible through the flame-retardant wallpaper, thereby providing a more colorful flame-retardant wallpaper.

A ninth aspect of the present invention is the flame-retardant wallpaper according to the first aspect, characterized in that the dry weight of the paint for the receiving layer impregnated into the receiving layer is 1.5 g/m ² to 137 g/m ² .

According to the ninth aspect, it is possible to provide flame-retardant wallpaper with higher flame retardancy that can be certified as a "non-combustible material" under the Building Standards Act.

A tenth aspect of the present invention is the flame-retardant wallpaper according to the first aspect, characterized in that the viscosity of the paint for the receiving layer before impregnation into the receiving layer is in the range of 0.26 Pa·s to 1.7 Pa·s.

According to the tenth aspect, an appropriate amount of paint for the receiving layer can be uniformly impregnated into the nonwoven fabric, making it possible to produce flame-retardant wallpaper with excellent aesthetics.

An eleventh aspect of the present invention is the flame-retardant wallpaper described in the first aspect, characterized in that the ten-point average roughness of one surface of the sheet substrate is 8 μm to 14 μm.

According to the 11th aspect, a receiving layer of sufficient thickness can be formed, making it possible to provide flame-retardant wallpaper that is less likely to impair aesthetic appearance.

A twelfth aspect of the present invention is the flame-retardant wallpaper according to the first aspect, characterized in that an ink layer containing a pigment is provided on the receiving layer.

In this twelfth aspect, it is possible to provide flame-retardant wallpaper printed with fine letters, colors, etc.

A thirteenth aspect of the present invention is the flame-retardant wallpaper described in the first aspect, characterized in that one surface of the sheet substrate is embossed.

According to the thirteenth aspect, it is possible to provide flame-retardant wallpaper that improves aesthetic appearance while preventing it from being damaged.

FIG. 1 is a schematic side view of a flame-retardant wallpaper according to a first embodiment. FIG. 2 is a graph showing the test results of the tensile strength test. FIG. 3 is a schematic side view of a flame-retardant wallpaper according to a third embodiment. FIG. 4 is a table showing the configuration of test specimen A. FIG. 5 is a table showing the configuration of test specimen B. FIG. 6 is a table showing the configuration of test specimen C. FIG. 7 shows the measurement results of the condensation test for the fire resistance performance test of the wallpaper/gypsum board test specimen A. FIG. 8 shows the measurement results of the condensation test for the fire resistance performance test of wallpaper/gypsum board for test specimen B. FIG. 9 shows the measurement results of the condensation test for the fire resistance performance test of wallpaper/gypsum board for test specimen C. FIG. 10 is a schematic side view of the flame-retardant wallpaper according to the fourth embodiment. FIG. 11 is a schematic side view of the flame-retardant wallpaper according to the fifth embodiment.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, flame-retardant wallpaper according to the present invention will be described with reference to the accompanying drawings. However, the present invention is not limited to the following embodiments.
(Embodiment 1)

Figure 1 is a schematic side view of flame-retardant wallpaper according to embodiment 1. As shown in this figure, flame-retardant wallpaper 1 according to this embodiment is composed of a nonwoven fabric 10, which is a sheet substrate, and which has on one surface (top surface) a receiving layer 15 impregnated with a paint for the receiving layer.

First, we will explain nonwoven fabric 10. There are no particular restrictions on the structure of nonwoven fabric 10, as long as it contains 5-55% by weight of polyester fiber and 45-95% by weight of pulp. Naturally, nonwoven fabric 10 also includes fabrics composed of 10-20% by weight of polyester fiber, 40-50% by weight of pulp, and 30-50% by weight of other components.

The pulp is not particularly limited, but can be softwood bleached chemical pulp (NBCP), hardwood bleached chemical pulp (LBCP), or a mixture of these. The cross-sectional shape of the pulp is also not particularly limited, but circular or elliptical shapes (excluding irregular cross-sections) are preferred, as they improve tensile strength by allowing the pulp to intertwine appropriately. The diameter of the pulp and polyester fibers is preferably 5 to 20 μm, and more preferably 10 to 15 μm.

While there are no particular limitations on the polyester fibers, fibers such as polyethylene terephthalate (PET) and polybutylene terephthalate (PBT) are preferred.

Nonwoven fabrics with this configuration have high tensile strength (e.g., 100 N/15 mm or more), which prevents cracking or tearing of the flame-retardant wallpaper 1 due to movement of the structure caused by drying of the structure or shaking of the earth's crust. If the tensile strength is less than 100 N/15 mm, cracking or tearing of the flame-retardant wallpaper may occur due to movement of the structure.

Furthermore, the nonwoven fabric 10 configured in this manner has a low underwater elongation (wetted elongation) (for example, 0.5% or less, preferably 0.3% or less), and therefore does not expand easily even when absorbing water (humidity). As a result, tearing of the flame-retardant wallpaper 1 due to water absorption can be prevented. If the underwater elongation is greater than 1%, tearing of the flame-retardant wallpaper due to water absorption may occur. Furthermore, the nonwoven fabric 10 configured in this manner has sufficient moisture absorption (for example, 105 g/ ^m2 or more) and moisture release (for example, 77 g/ ^m2 or more). Here, moisture absorption refers to the ability to absorb water (humidity) from the air, and moisture release refers to the ability to release absorbed moisture.

The weight ratios of polyester fiber and pulp are not particularly limited, as long as they are 5-55% by weight and 45-95% by weight, respectively. However, 5-40% by weight and 60-95% by weight are preferred, as they combine higher tensile strength and lower elongation in water. 20-35% by weight and 65-80% by weight are particularly preferred, as they combine even higher tensile strength and even lower elongation in water. In addition, nonwoven fabric 10 with this configuration can better prevent cracking and tearing of flame-retardant wallpaper 1 due to movement of the frame or moisture absorption. Nonwoven fabric 10 may also be configured to contain glass fiber in addition to polyester fiber and pulp. The inclusion of glass fiber can improve the strength and durability of nonwoven fabric 10.

Furthermore, in addition to these fibers, nonwoven fabric 10 may contain titanium oxide or other stabilizers, and may also contain synthetic rubber, acrylic, vinyl acetate, vinyl chloride, or urethane binders. It goes without saying that nonwoven fabric 10 does not have to contain anything other than polyester fibers and pulp.

In addition, the ten-point mean roughness (Rz) of one surface of the nonwoven fabric 10 (the surface on which the receiving layer 15 is formed) is preferably 8 μm to 14 μm. If the ten-point mean roughness is less than 8 μm, it is difficult for the receiving layer paint to penetrate the nonwoven fabric 10, and a receiving layer 15 of sufficient thickness cannot be formed. On the other hand, if the ten-point mean roughness is greater than 14 μm, the receiving layer 15 is prone to peeling. As a result, the aesthetic appearance of the flame-retardant wallpaper 1 is easily impaired. It is particularly preferable that the ten-point mean roughness of the one surface of the nonwoven fabric 10 (the surface on which the receiving layer 15 is formed) be 9 μm to 13 μm. A nonwoven fabric 10 with such a structure has sufficient thickness, making it easy to form a receiving layer 15 that is resistant to peeling. The ten-point mean roughness (Rz) can be measured using, for example, a Zygo white light interferometer such as the NEXVIEW.

Furthermore, it is preferable that the crystallinity of the polyester fibers on the surface of the nonwoven fabric 10 is lower than the crystallinity of the polyester fibers inside the nonwoven fabric 10. A nonwoven fabric with such a structure can improve the flexibility of the nonwoven fabric 10 without changing the tensile strength or elongation in water. The crystallinity of the polyester fibers can be determined, for example, by comparing the melting points of the polyester fibers (it can be determined that polyester fibers with lower melting points have lower crystallinity than polyester fibers with higher melting points). Note that such nonwoven fabrics can be produced by heating and then rapidly cooling, for example.

Next, we will explain the receiving layer 15. There are no restrictions on the thickness of the receiving layer 15 as long as it is a layer in which one side of the nonwoven fabric 10 is impregnated with the receiving layer paint, but the dry weight of the receiving layer paint impregnated into the receiving layer 15 must be 1 g/m ² to 150 g/m ² .

If the dry weight of the paint for the receiving layer impregnated into the receiving layer 15 is less than 1 g/ ^m2 , the thickness of the receiving layer 15 will be insufficient and unsuitable, which will likely impair the aesthetic appearance of the flame-retardant wallpaper 1. On the other hand, if the dry weight of the paint for the receiving layer impregnated into the receiving layer 15 is more than 150 g/ ^m2 , the amount of heat generated when burned will increase, making it impossible to meet the above-mentioned flame-retardant conditions.

The dry weight of the receiving layer paint impregnated into the receiving layer 15 is preferably 1.5 g/m ² to 137 g/m ² , and particularly preferably 16 g/m ² to 70 g/m ^2. A receiving layer 15 with a dry weight of the receiving layer paint in this range has a sufficient thickness and is resistant to scraping and cracking. As a result, the flame-retardant wallpaper 1 is easy to handle and does not easily lose its aesthetic appearance. In addition, the amount of heat generated during combustion can be reduced.

Here, the receiving layer paint is not particularly limited as long as it contains a synthetic resin as its main component and can be impregnated into the nonwoven fabric 10. Using a receiving layer paint containing a synthetic resin makes it possible to flatten one surface of the nonwoven fabric 10. The synthetic resin contained in the receiving layer paint is not particularly limited, but acrylic resin, cellulose acetate, vinyl chloride resin, vinyl acetate resin, polyester, and urethane are preferred, with acrylic resin being particularly preferred. In particular, when a receiving layer paint containing acrylic resin as its main component is used, the acrylic resin impregnates the nonwoven fabric 10, thereby improving the strength of the flame-retardant wallpaper while maintaining its flexibility, compared to when other synthetic resins are used. Here, acrylic resin refers to a polymerized acrylic acid, methacrylic acid, or a derivative thereof.

The coating material for the receiving layer may contain one or more photocatalytic materials, such as calcium hydroxide and magnesium hydroxide, and other hydrated metal compounds. There are no particular limitations on the photocatalytic material, as long as it has photocatalytic functionality, and examples include titanium dioxide, which has photocatalytic functionality.

Furthermore, it is preferable that the viscosity of the receiving layer paint before impregnation into the receiving layer 15 is 0.26 Pa·s to 1.7 Pa·s. If the viscosity of the receiving layer paint is less than 0.26 Pa·s, the receiving layer paint cannot be sufficiently applied to the surface of the nonwoven fabric 10, and the appropriate amount of receiving layer paint cannot be uniformly impregnated into the nonwoven fabric 10. This results in a flame-retardant wallpaper 1 that is not aesthetically pleasing. On the other hand, if the viscosity of the receiving layer paint is greater than 1.7 Pa·s, the appropriate amount of receiving layer paint cannot be uniformly impregnated. Note that viscosity can be measured using a Zahn cup No. 5 or similar at a temperature of 20°C for the receiving layer paint.

Next, a method for manufacturing the flame-retardant wallpaper 1 according to this embodiment will be described. The flame-retardant wallpaper 1 according to this embodiment can be manufactured as follows. First, a coating material for the receiving layer is applied to one side of the nonwoven fabric 10 using a coater such as a roll coater. Next, the nonwoven fabric to which the coating material for the receiving layer has been applied is dried. Thereafter, the flame-retardant wallpaper 1 can be manufactured by cutting into a predetermined shape.
(Embodiment 2)

In the above-described embodiment, the nonwoven fabric is made of polyester fibers and pulp, but the present invention is not limited to this. For example, the nonwoven fabric may be made of 10 to 30% by weight of polyester, 60 to 85% by weight of pulp, and 1 to 5% by weight of polyolefin fibers.

Nonwoven fabrics with this structure have improved water resistance and adhesion due to the inclusion of polyolefin fibers, resulting in higher tensile strength, lower elongation in water, and less pilling. As a result, it is possible to provide flame-retardant wallpaper that combines high tensile strength and low elongation in water, and is more resistant to cracking and tearing due to movement of the frame or moisture absorption.

Here, the polyolefin fibers are not particularly limited, but those made of polyethylene or polypropylene are preferred. By using polyolefin fibers made of polyethylene or polypropylene, a nonwoven fabric with even higher tensile strength and even lower elongation in water will be obtained.

Furthermore, a composition containing 20-30% polyester fiber by weight, 60-70% pulp by weight, and 3-5% polyolefin fiber by weight is preferable, as it will have even higher tensile strength and even lower elongation in water.

The nonwoven fabric may contain the above-mentioned glass fibers, stabilizers, binders, etc. in addition to the polyester fibers, pulp, and polyolefin fibers, but it goes without saying that it is not necessary for them to be contained.
<Tensile strength test>

A tensile strength test was carried out on the nonwoven fabric according to the present invention (Example 1) and a conventional vinyl cloth (Comparative Example 1).
Example 1
Nonwoven fabric: Nonwoven fabric composed of 30% by weight of polyester fibers (PET and PBT), 67% by weight of pulp, and 3% by weight of polyolefin fibers (PE and PP) [Comparative Example 1]
Vinyl cloth: SP2350 (manufactured by Sangetsu Co., Ltd.)

The tensile strength of these sheet substrates was measured in accordance with JIS P 8113. The results are shown in Figure 2. As shown in this figure, it was found that the nonwoven fabric (a1) according to this embodiment exhibited higher values for both longitudinal and transverse tensile strength compared to the conventional vinyl cloth (b1). In this test, the longitudinal direction refers to the longitudinal direction of the nonwoven fabric manufactured in a roll shape before cutting, and the transverse direction refers to the transverse direction of the nonwoven fabric manufactured in a roll shape before cutting.
(Embodiment 3)

In embodiment 1, nothing was provided on the surface of the other side of the nonwoven fabric substrate, but an adhesive layer impregnated with adhesive may also be provided. Figure 3 is a schematic side view of the flame-retardant wallpaper according to this embodiment. As shown in this figure, an adhesive layer 20 is provided on the other side (underside) of the nonwoven fabric 10.

The adhesive layer 20 may be formed by impregnating the other side of the nonwoven fabric 10 with adhesive, or by applying adhesive to the surface of the other side of the nonwoven fabric 10, or by impregnating part of the adhesive into the other side of the nonwoven fabric 10 and applying the other adhesive to the surface of the other side of the nonwoven fabric 10. By forming the adhesive layer 20, the flame-retardant wallpaper 1A can be easily attached to the wall of a building, etc.

Here, the thickness of the adhesive layer 20 is preferably 0.01 mm to 5 mm. If it is less than 0.01 mm, it will not have sufficient adhesive strength, and there is a risk that the flame-retardant wallpaper will peel off from the wall surface, etc. On the other hand, if it is more than 5 mm, the amount of heat generated during combustion will increase, and the flame-retardant conditions described above will no longer be met. It is more preferable that the thickness of the adhesive layer 20 be 0.1 mm to 2 mm. If the thickness of the adhesive layer 20 is within this range, it will be possible to provide flame-retardant wallpaper that has sufficient adhesive strength and meets the flame-retardant conditions described above.

The adhesive is not particularly limited as long as it can adhere the flame-retardant wallpaper 1A to the wall of a building, etc. Preferred adhesives include starch-based adhesives whose main component is starch, adhesives whose main component is acrylic ester, and re-moistening or hot-melt adhesives that become sticky by absorbing moisture.

Examples of starch-based adhesives include Wallbond (registered trademark) 100 (manufactured by Wallbond Industries Co., Ltd.) and RuaMild (registered trademark) (manufactured by Yayoi Chemical Industry Co., Ltd.).

Examples of acrylic esters contained in adhesives whose main component is acrylic ester include ethyl acrylate, butyl acrylate, 2-ethylhexyl acrylate, and 2-hydroxyethyl acrylate.

The rewettable glue is not particularly limited as long as it is a starch-based rewettable glue that contains starch as its main ingredient and becomes sticky when it absorbs moisture, or an adhesive that contains a water-soluble acrylic resin and becomes sticky when it absorbs moisture, but starch-based rewettable glue is preferred. Examples of rewettable glues include polyvinyl alcohol (PVA, poval), shoji/fusuma glue (manufactured by Asahi Pen Co., Ltd.), and W&W Perfect (manufactured by Nakamura Paper Co., Ltd.).

The hot melt adhesive is not particularly limited as long as it can be melted and bonded by applying heat (e.g., 80-100°C). Examples include adhesives whose main component is ethylene vinyl acetate copolymer (EVA), olefins, or synthetic rubber (elastomers), with olefin adhesives whose main component is polypropylene or polyethylene being preferred. Examples of hot melt adhesives include Aronmelt PPET (manufactured by Toa Gosei Co., Ltd.) and P-10 (manufactured by Taihei Chemack Co., Ltd.).

Furthermore, the ten-point mean roughness (Rz) of the surface of the nonwoven fabric 10 on which the adhesive layer 20 is provided is preferably 8 μm to 14 μm. If the ten-point mean roughness is less than 8 μm, it is difficult for the adhesive to impregnate the nonwoven fabric 10, and it is not possible to form an adhesive layer 20 with sufficient thickness. On the other hand, if the ten-point mean roughness is greater than 14 μm, the adhesive layer 20 becomes more likely to peel. As a result, the flame-retardant wallpaper 1A becomes more likely to peel from the wall or the like. It is particularly preferable that the ten-point mean roughness of the surface of the other side of the nonwoven fabric 10 (the side on which the adhesive layer 20 is formed) be 9 μm to 13 μm. A nonwoven fabric 10 with such a structure can easily form an adhesive layer 20 that is sufficiently thick and does not peel easily.
<Fire resistance test for wallpaper/gypsum board>

Test specimens A to C according to the present invention, shown in Figures 4 to 6, were subjected to a "fire resistance test for wallpaper/gypsum board" at the Japan Testing Center for Construction Materials. The results are shown in Figures 7 to 9, respectively.

As can be seen from these results, test specimens A to C met the above-mentioned flame retardancy requirements.
(Embodiment 4)

In embodiment 3, an adhesive layer is provided directly on the surface of the other side of the nonwoven fabric, but the present invention is not limited to this. For example, as shown in Figure 10, a colored colored layer 50 may be provided between the nonwoven fabric 10 and the adhesive layer 20. By providing the colored layer 50, it is possible to prevent the color of the wall to which the flame-retardant wallpaper is attached from being visible through the flame-retardant wallpaper 1B. In other words, it is possible to improve the concealment properties of the flame-retardant wallpaper 1B.

Here, the colored layer 50 is made of a colored material, such as white, and is not particularly limited as long as the color of the wall surface to which it is attached is not visible through the flame-retardant wallpaper 1B. Examples of the colored layer 50 include those formed by impregnating the other side of the nonwoven fabric 10 with paint containing white or other colored pigments, paper colored white or other colors, olefin sheets, synthetic paper, etc. It goes without saying that if the colored layer 50 is made of colored paper, it will be necessary to attach the paper to the other surface of the nonwoven fabric 10 using an adhesive such as those described above. Note that the concealment properties can be further improved by coloring the adhesive.

The thickness of the colored layer 50 is not particularly limited, but a thickness of 0.02 mm to 0.9 mm is preferable because it does not affect flame retardancy and prevents the wall color from showing through, and a thickness of 0.07 to 0.3 mm is even more preferable. If it is thinner than 0.02 mm, the wall color will be visible through the flame-retardant wallpaper 1B. On the other hand, if it is thicker than 0.9 mm, the amount of heat generated during combustion will increase, making it impossible to meet the flame-retardant requirements described above and making it difficult to apply to walls, etc.
(Embodiment 5)

In the above-described embodiment, nothing was provided on the receiving layer, but the present invention is not limited to this. For example, as shown in Figure 11, an ink layer 30 containing a pigment may be provided on the receiving layer 15. By providing the ink layer 30, it is possible to provide flame-retardant wallpaper 1C on which fine letters, colors, etc. are printed.

Here, the ink layer 30 is not particularly limited as long as it contains a pigment. The ink layer 30 can be formed, for example, by applying a paint such as a polymer onto the receiving layer 15 using an inkjet printer and then drying the paint. The ink layer 30 may have a single-layer structure or a multi-layer structure consisting of two or more layers.

There are no particular limitations on the thickness of the ink layer 30, but a thickness in the range of 0.01 mm to 0.03 mm is preferable. If it is thinner than 0.01 mm, the color will not develop sufficiently, and if it is thicker than 0.03 mm, the ink layer 30 will easily peel off.

Next, we will explain the ink used to form the ink layer 30. There are no particular limitations on the ink, and solvent ink, water-based ink, latex ink, ultraviolet-curable ink (UV ink), etc. can be used, but latex ink or UV ink is preferred.

When latex ink is used as the ink, it is heated when applied to the flame-retardant wallpaper 1C, solidifying the latex ink on the surface of the flame-retardant wallpaper 1C (on the receiving layer 15) to form an ink layer 30, thereby improving the strength of the flame-retardant wallpaper 1C.

Furthermore, when UV ink is used as the ink, the UV ink is applied to the surface layer (on the receiving layer 15) of the flame-retardant wallpaper 1C, and then ultraviolet light is irradiated to solidify the UV ink on the surface layer (on the receiving layer 15) of the flame-retardant wallpaper 1C, forming an ink layer 30. This improves the strength of the flame-retardant wallpaper 1C, just like latex ink.

The thickness of the ink layer 30 formed on the receiving layer 15 is preferably 0.01 mm to 0.015 mm.

Furthermore, when using a water-based ink, a laminate film or the like may be attached to the receiving layer 15. The ink layer 30 may also be formed by applying a so-called optimizer and then applying the ink.
(Other embodiments)

In the above-described embodiment, the surface of the flame-retardant wallpaper is not embossed, but it may be embossed. The embossing method can be the same as that used to emboss conventional wallpaper. By embossing the surface of the flame-retardant wallpaper, the unevenness of the underlying surface, such as the wall of a building, is less likely to appear on the surface of the flame-retardant wallpaper, thereby improving the aesthetic appearance of the flame-retardant wallpaper. In addition, an air layer is formed between the flame-retardant wallpaper and the underlying surface, so even if the flame-retardant wallpaper becomes wet with water, it dries more easily than non-embossed flame-retardant wallpaper.

1, 1A, 1B, 1C Flame-retardant wallpaper 10 Nonwoven fabric (sheet substrate)
15 Receptor layer 20 Adhesive layer 30 Ink layer 50 Colored layer

Claims (11)

A flame-retardant wallpaper having a receiving layer impregnated with a coating material for the receiving layer on one side of a sheet substrate,
the sheet substrate is a nonwoven fabric containing 5 to 55% by weight of polyester fiber and 45 to 95% by weight of pulp;
the dry weight of the coating material for the receiving layer impregnated into the receiving layer is 1 g/m ² to 150 g/m ² ;
The coating material for the receiving layer contains a synthetic resin as a main component ,
the synthetic resin is an acrylic resin, a cellulose acetate resin, a vinyl acetate resin, a polyester, or a urethane;
the crystallinity of the polyester fibers on one surface of the sheet substrate is lower than the crystallinity of the polyester fibers inside the sheet substrate;
Flame-retardant wallpaper characterized by 2. The flame-retardant wallpaper according to claim 1, wherein the sheet substrate contains 5 to 40% by weight of the polyester fiber and 60 to 95% by weight of the pulp. The flame-retardant wallpaper described in claim 1, characterized in that the sheet substrate is a nonwoven fabric containing 20 to 35% by weight of polyester and 65 to 80% by weight of pulp. The flame-retardant wallpaper described in claim 1, characterized in that the sheet substrate is a nonwoven fabric containing 10 to 30% by weight of polyester, 60 to 85% by weight of pulp, and 1 to 5% by weight of polyolefin fibers. an adhesive layer formed by applying an adhesive to the other surface of the sheet substrate;
The adhesive is a starch-based adhesive containing starch as a main component, an adhesive containing acrylic ester as a main component, a rewettable adhesive or a hot melt adhesive that becomes sticky by absorbing moisture,
2. The flame-retardant wallpaper according to claim 1, wherein the adhesive layer has a thickness of 0.01 mm to 5 mm. 6. The flame-retardant wallpaper according to claim 5 , wherein a colored layer is provided between the sheet substrate and the adhesive layer. 2. The flame-retardant wallpaper according to claim 1, wherein the weight of the paint for the receiving layer impregnated into the receiving layer is 1.5 g/m ² to 137 g/m ² when dry. The flame-retardant wallpaper described in claim 1, characterized in that the viscosity of the paint for the receiving layer before impregnation into the receiving layer is in the range of 0.26 Pa·s to 1.7 Pa·s. The flame-retardant wallpaper described in claim 1, characterized in that the ten-point average roughness of one surface of the sheet substrate is 8 μm to 14 μm. The flame-retardant wallpaper described in claim 1, characterized in that an ink layer containing a pigment is provided on the receiving layer. 2. The flame-retardant wallpaper according to claim 1, wherein one surface of the sheet substrate is embossed.