JP2013170336A - Sheet for wallpaper - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a sheet for a wallpaper, which does not have such a problem as to drop powders caused by falling of a filler, and can obtain sufficient concealing properties without using backing paper and the like, in a sheet for a wallpaper for interior decorating, which is used in a house and the like.SOLUTION: The sheet for the wallpaper comprises a nonwoven fabric containing wood pulp and a synthetic fiber. A brightness Lof the rear face side of the sheet for the wallpaper is set at 30-80.

Description

  The present invention relates to a wall paper sheet for interior use used in a house or the like, and in particular, a wall paper sheet having excellent concealment properties such as a wall surface, glue remaining without peeling, and scratches on the wall. It is about.

  Conventional wallpaper mainly includes a base paper for wallpaper provided with a polyvinyl chloride resin layer. However, polyvinyl chloride has been avoided from the viewpoint of waste disposal and the like, and wallpaper using non-woven fabric has come to be used.

  On the other hand, wallpaper with a polyvinyl chloride resin layer is easy to improve concealment by kneading pigments into the resin layer, while wallpaper using non-woven fabric has good texture, but concealment There was a problem that was difficult to raise.

  In order to solve this problem, a method of providing a highly concealed backing paper between a wall and wallpaper has been proposed (see, for example, Patent Documents 1 and 2). However, although this method can improve concealment, productivity is poor because a process of providing backing paper is required. Moreover, in order to raise opacity and to improve concealability, the wallpaper sheet which consists of a nonwoven fabric which contains the pulp-like multibranched fiber as a synthetic fiber is proposed (for example, refer patent documents 3-4). However, it is not possible to obtain a sufficient concealment property simply by increasing the opacity using pulp-like multibranched fibers. Moreover, as a method for improving the concealability of paper or nonwoven fabric, a method of increasing the opacity by adding an inorganic or organic filler is generally used (see, for example, Patent Document 5). However, in order to obtain sufficient concealability, the amount of filler must be increased, and there are problems such as powder falling off due to falling off of the filler and a decrease in strength due to a relative decrease in the amount of fiber.

  As described above, there has not been obtained a wallpaper sheet that does not have a problem of powder falling off due to the falling off of the filler and that can provide sufficient concealment without using backing paper or the like.

Japanese Patent Laid-Open No. 2008-190080 JP 2005-205973 A JP 2004-3048 A JP 2004-233872 A JP 2011-219874 A

  An object of the present invention is to provide a wallpaper sheet that can be sufficiently concealed without using a backing paper or the like in a wallpaper sheet for interior use used in a house, etc. Is to provide.

  Specific means for solving this problem is as follows.

(1) A wallpaper sheet comprising a nonwoven fabric containing wood pulp and synthetic fibers, wherein the lightness L ^* on the back side of the wallpaper sheet is 30 to 80.

  (2) The wallpaper sheet according to (1), wherein the wallpaper sheet is a nonwoven fabric in which at least two layers are laminated, and a color material is contained in a layer on the back side of the wallpaper sheet.

  (3) The wallpaper sheet according to (1) or (2), wherein an ink or a coating liquid containing a color material is printed or applied on the back side of the wallpaper sheet.

  According to the present invention, it is possible to provide a wallpaper sheet that does not have a problem of powder falling off due to the falling off of the filler, and that can sufficiently conceal without using a backing paper or the like.

The wallpaper sheet of the present invention is a wallpaper sheet made of a nonwoven fabric containing wood pulp and synthetic fibers, and has a lightness L ^* of 30 to 80 on the back side of the wallpaper sheet.

  First, the reason why the wallpaper sheet of the present invention is a nonwoven fabric containing wood pulp and synthetic fibers will be described below.

  The wallpaper sheet may be used in a solid color, but is generally used by printing a predetermined pattern on the surface by a method such as gravure printing or flexographic printing. A nonwoven fabric using synthetic fibers has a cloth-like texture and is suitable as a sheet for wallpaper. In general, synthetic fibers have poorer printability than wood pulp. On the other hand, wood pulp has good printability even if it is made into a sheet alone. Therefore, by using a nonwoven fabric containing both wood pulp and synthetic fibers, a wallpaper sheet having a cloth-like texture can be obtained without impairing printability.

  The ratio of the wood pulp and the synthetic fiber contained in the wallpaper sheet of the present invention is preferably 90:10 to 20:80, more preferably 85:15 to 50:50 in terms of mass ratio. If the content of the synthetic fiber is too small and the content of the wood pulp is too large, it may be susceptible to humidity, for example, a cloth-like texture cannot be obtained or it expands and contracts due to a change in humidity. On the other hand, if the synthetic fiber content is too high and the wood pulp content is too low, the printability may be deteriorated. Moreover, when manufacturing by a wet papermaking method, the water retention of the sheet before drying becomes poor, and it may be difficult to peel off from the felt.

Next, the reason why the lightness L ^* of the back side (the surface attached to the wall of the wallpaper sheet) is 30 to 80 in the wallpaper sheet of the present invention will be described.

If the wallpaper sheet is not concealed, the background of the wall, glue remaining without peeling, and scratches on the wall will be on the surface side of the wallpaper sheet (opposite to the surface attached to the wall of the wallpaper sheet). May show through. By darkening the lightness L ^* of the back side of the wallpaper sheet (lowering the lightness L ^* ), it becomes difficult to see through the background of the wall from the front side. That is, the concealment property can be improved. A low lightness L ^* is preferable because the concealability is high, but if the lightness is too low, the printed pattern or white portion on the front side may feel dark. In addition, if the lightness is too high, a sufficient concealing effect may not be obtained, so the lightness L ^* is 30 to 80, more preferably 40 to 70. The lightness L ^{* referred} to in the present invention was measured by stacking five wallpaper sheets with the back side facing up, and measuring the back side of the top wallpaper sheet under the conditions of a D50 light source and a two-degree field of view. Let L ^* .

The wallpaper sheet of the present invention is preferably a nonwoven fabric in which at least two layers are laminated, and a wallpaper sheet in which a color material is contained in a layer on the back side of the wallpaper sheet. If the lightness L ^* on the front surface side is low, the printed pattern and the white part may feel dark. However, a non-woven fabric in which two or more layers are laminated, and a colorant is included in the backside layer, and the lightness L ^* on the backside is included ^. By lowering the value, the influence on the front surface side can be reduced, and the concealability can be enhanced while suppressing the influence on the printed pattern and the white part on the front surface side.

For the same reason, it is preferable to set the lightness L ^* on the back surface side to 30 to 80 by printing or coating an ink or a coating liquid containing a color material on the back surface side of the wallpaper sheet.

Furthermore, the lightness L ^* on the back surface side may be set to 30 to 80 by combining the above two methods.

In the present invention, as long as the lightness L ^* on the back surface side can be set to 30 to 80, the hue, saturation, etc. of the color material are not particularly limited, but black or blue dark dyes or pigments can be used in a small amount. Since L ^* can be lowered, it is preferable.

  Examples of such black or blue dark dyes or pigments include carbon black, phthalocyanine blue, cobalt phthalocyanine, dyed lake pigments, bitumen, complex oxide pigments, azo pigments, vinyl sulfone reactive dyes, disperse dyes , Basic dyes, cationic dyes, oil-soluble dyes, direct dyes, acid dyes, and the like, but the present invention is not limited thereto.

The blending amount of the color material used in the present invention is not particularly limited, but when used internally added to the nonwoven fabric, it is preferably 0.01 to 0.10% by mass with respect to the total fiber amount of the nonwoven fabric, It is more preferable that it is 0.02-0.08 mass%. Further, when the lightness L ^* on the back surface side is set to 30 to 80 by printing or coating ink or coating liquid containing the color material on the back surface side of the wallpaper sheet, the amount of the color material is 0. 0.1-10.0 g / m ² is preferable, and 0.5 g-5.0 g / m ² is more preferable. If the amount of the color material is too large, the lightness L ^* may become too low, and the printed pattern or white portion on the front side may feel dark. On the other hand, if the amount of the coloring material is too small, the lightness L ^* may not be lowered and the concealing property may not be improved.

  In the present invention, as a method for printing or coating an ink or a coating liquid containing a color material, for example, various printing methods such as flexo, screen, offset, gravure, ink jet, air knife, blade, rod, reverse roll Various coating methods such as film transfer, lip, die, curtain, spray and the like can be mentioned, but the present invention is not limited to these.

  The wood pulp used in the present invention may be NBKP, LBKP, NBSP, LBSP, GP, TMP, or any other type of pulp, and is not particularly limited, but NBKP is preferred from the viewpoint of strength. The Canadian standard freeness is preferably in the range of 300 to 600 ml CSF. If the Canadian standard freeness is less than 300 ml CSF, the dimensional stability of the non-woven fabric may be reduced. If the Canadian standard freeness exceeds 600 ml CSF, the strength of the non-woven fabric may be reduced.

  Synthetic fibers used in the present invention include polyolefins, polyesters, polyvinyl acetates, ethylene-vinyl acetate copolymers, polyamides, acrylics, polyvinyl chlorides, polyvinylidene chlorides, polyvinyl ethers, polyvinyl ketones. , Polyether, polyvinyl alcohol, diene, polyurethane, phenol, melamine, furan, urea, aniline, unsaturated polyester, alkyd, fluorine, silicone, polyamideimide, polyphenylene A sulfide system and a polyimide system can be used, but the present invention is not limited to these. The synthetic fiber may be a fiber (single fiber) made of a single resin, or may be a fiber (composite fiber) made of two or more kinds of resins. Examples of the composite fiber include a core-sheath type, an eccentric type, a side-by-side type, a sea-island type, an orange type, and a multiple bimetal type. These synthetic fibers may be used alone or in combination of two or more.

  In addition, when using polyester-based and polyolefin-based synthetic fibers, the resulting non-woven fabric not only has a cloth-like texture, but also has an appropriate softness suitable for embossing, etc., so the synthetic fibers are polyester-based or polyolefin-based It is preferable to use at least one selected from

  The fiber diameter of the synthetic fiber used in the present invention is preferably 4 to 40 μm, more preferably 5 to 25 μm, and even more preferably 7 to 15 μm. If the fiber diameter of the synthetic fiber is less than 4 μm, it may fall off from the paper making wire during paper making. On the other hand, when the fiber diameter of the synthetic fiber exceeds 40 μm, the number of fibers may be relatively reduced, the strength may be lowered, and the smoothness of the sheet surface may be inferior.

  The fiber length of the synthetic fiber is preferably 1 to 20 mm, more preferably 2 to 15 mm, and still more preferably 3 to 10 mm. If the fiber length of the synthetic fiber is less than 1 mm, the fibers are hardly entangled and the strength may be lowered. On the other hand, when the fiber length of the synthetic fiber exceeds 20 mm, it may become easy to generate kinks or clumps during paper making, and the formed nonwoven fabric may become non-uniform.

  The method for producing the nonwoven fabric according to the present invention is not particularly limited, and can be selected and used as needed, such as dry methods such as spunbond, chemical bond, melt blow, and wet papermaking. It is easy to make pulp into a slurry, it is easy to mix and use multiple fibers with different fiber lengths and fineness, if necessary, a filler to increase opacity, and a sizing agent to further increase water repellency Can be added internally, and wet papermaking is particularly preferred. The nonwoven fabric may have a multilayer structure. The multilayer structure can be manufactured by a combination paper machine, or may be manufactured by laminating using a separate processing machine.

  Moreover, in this invention, it is preferable that a nonwoven fabric contains at least 1 sort (s) chosen from polyvinyl alcohol (PVA) type fiber, viscose type fiber, polyester type fiber, and polyolefin type fiber as a binder fiber. Two or more kinds of binder fibers may be used in combination. The binder fiber may be a single fiber or a composite fiber such as a core-sheath fiber or a split fiber.

  In particular, hot water-soluble binder fibers, such as PVA fibers, are hardly dissolved in room temperature water and maintain the fiber form. However, when heated in a state containing moisture after papermaking, they begin to dissolve easily. Once dissolved, when pressed with equipment such as a touch roll, it develops a binder ability that works between synthetic fibers and wood pulp, and then re-solidifies by dehydration and drying, and it can be done easily only in high-temperature water. This is particularly preferable because it is a strong binder fiber that does not dissolve.

  5-50 mass% is preferable with respect to the total fiber content of a nonwoven fabric, 7-40 mass% is more preferable, and, as for content of a binder fiber, 10-30 mass% is further more preferable. When the content of the binder fiber is less than 5% by mass, the tensile strength is weak and the paper may be cut off during wet papermaking. If the content of the binder fiber exceeds 50% by mass, the non-woven fabric becomes hard and the cloth-like texture is impaired, and the printability may be deteriorated due to the relatively decreased content of the wood pulp.

  When the binder fiber used in the present invention is a synthetic fiber, the binder fiber is also included in the synthetic fiber content when calculating the synthetic fiber content.

  The fiber diameter of the binder fiber according to the present invention is preferably 4 to 40 μm, more preferably 6 to 25 μm, and still more preferably 10 to 18 μm. If the fiber diameter of the binder fiber is less than 4 μm, it may fall off from the paper making wire during paper making, and the binder ability may be reduced. On the other hand, when the fiber diameter of the binder fiber exceeds 40 μm, the specific surface area of the fiber is relatively decreased, the binder ability may be decreased, and the smoothness of the sheet surface may be deteriorated. The fiber length of the binder fiber is preferably 1 to 20 mm, more preferably 2 to 15 mm, and still more preferably 3 to 10 mm. When the fiber length of the binder fiber is less than 1 mm, the binder ability may be lowered. On the other hand, when the fiber length of the binder fiber exceeds 20 mm, the paper fabric is likely to be twisted or hardened, and the formed nonwoven fabric may be uneven.

  The nonwoven fabric according to the present invention may contain fibers other than wood pulp, synthetic fibers, and binder fibers as necessary for the purpose of adjusting voids and strength. Examples of such fibers include regenerated fibers such as rayon, cupra, and lyocell fibers, and inorganic fibers such as glass, silica, ceramics, and rock wool. However, the present invention is not limited to these. Absent.

The basis weight of the nonwoven fabric according to the present invention is preferably 15~200g / ^{m 2,} more preferably 20 to 120 g / ^{m 2,} more preferably 30 to 100 g / ^{m 2.} When the basis weight of the nonwoven fabric is less than 15 g / m ² , the strength may be weakened. Moreover, when the basic weight of a nonwoven fabric exceeds 200 g / m < ² >, not only the texture as a wallpaper is bad, but it may become easy to peel from a wall with dead weight. In addition, the basic weight said by this invention means the basic weight based on the method prescribed | regulated to JISP8124 (paper and paperboard-basic weight measuring method). Moreover, 50-500 micrometers is preferable, as for the thickness of a nonwoven fabric, 70-350 micrometers is more preferable, and 100-300 micrometers is more preferable. When the thickness of the nonwoven fabric is less than 50 μm, rigidity may be insufficient or post-processing such as embossing may be difficult. If it exceeds 500 μm, uneven printing may easily occur. In addition, the thickness of the base material said by this invention means the value measured using the outside micrometer by the method prescribed | regulated to JISB7502. The density of the nonwoven fabric is preferably 0.10~0.90g / cm ^3, more preferably 0.20~0.80g / cm ^3, more preferably 0.30~0.70g / cm ^3. When the density of the non-woven fabric is less than 0.10 g / cm ³ , adhesion between fibers becomes poor, and dimensional stability may not be ensured. On the other hand, if the density of the nonwoven fabric exceeds 0.90 g / cm ³ , the nonwoven fabric becomes hard and post-processing such as embossing may be difficult.

  Moreover, the nonwoven fabric concerning this invention can be mix | blended with a size agent as needed in the range which does not have a bad influence on other quality. As the sizing agent, any reinforced rosin sizing agent, rosin emulsion sizing agent, petroleum resin sizing agent, synthetic sizing agent, neutral rosin sizing agent, alkyl ketene dimer (AKD) may be used as long as the desired effect of the present invention is not impaired. Any of known sizing agents such as) can be used.

  In addition to these, an anionic, nonionic, cationic or amphoteric retention improver, a filtering agent, a dispersant, a paper strength improver and a sticking agent are appropriately selected and used as necessary. In addition, internal additives for papermaking such as a pH adjuster, an antifoaming agent, a pitch control agent, and a slime control agent can be appropriately added depending on the purpose.

  In addition, if necessary, fillers such as clay, kaolin, calcined kaolin, talc, calcium carbonate, titanium dioxide, and self-extinguishing properties such as aluminum hydroxide and magnesium hydroxide can be used to increase opacity. A non-woven fabric can contain a filler or the like. Further, these fillers may be used by coating on the surface of the nonwoven fabric together with a binder such as a water-soluble resin or latex.

In addition, the wallpaper sheet of the present invention provides sufficient concealment without using backing paper or the like, so it may be applied to the wall as it is, but the purpose is to further improve the processing suitability such as embossing. May be used as a cover, and may be used by adhering to a backing paper. When the backing paper is used, the basis weight of the backing paper is not particularly limited, but is preferably 40 to 150 g / m ² in order to improve processability. As the backing paper, paper, a synthetic resin film, or a sheet bonded with these is preferable because it is easy to handle. Further, a backing paper having a small dimensional change when glued using a sizing agent or synthetic fiber is preferable. In order to further improve the concealing property, a backing paper to which concealing property is imparted with a filler such as clay, kaolin, calcined kaolin, talc, calcium carbonate, titanium dioxide or the like may be used.

  The wallpaper sheet of the present invention may be used as it is, but a pattern is printed as necessary. Examples of printing methods include gravure printing, screen printing, flexographic printing, and the like, and these methods can be used alone or in combination. Moreover, you may give the embossing for forming an uneven | corrugated pattern in the sheet | seat for wallpaper of this invention. Further, printing and embossing may be performed after bonding the backing paper.

  EXAMPLES Hereinafter, the present invention will be specifically described with reference to examples, but the present invention is not limited to the examples. Further, in the examples, unless otherwise indicated, parts and percentages are based on mass.

[Preparation of synthetic fiber dispersion]
Synthetic fibers and binder fibers were added to the water in the pulper dispersion tank at the ratio shown in Table 1, and mixed and dispersed for 10 minutes to prepare a synthetic fiber dispersion.

The details of the abbreviations shown in Table 1 are as follows.
F-1: Short polyester fiber. Fineness 0.6 dtex. Fiber length 5 mm.
F-2: Polypropylene short fiber. Fineness 0.8dtex. Fiber length 5 mm.
B-1: Thermal fusion type core-sheath binder fiber. Low-melting point copolyester having a core polyester and sheath flow starting temperature of 110 ° C. Fineness 2.2 dtex. Fiber length 5 mm.
B-2: Hot water soluble binder fiber (PVA fiber). Fineness 1.1 dtex. Fiber length 3mm.
P: NBKP (wood pulp).

[Preparation of wood pulp dispersion]
NBKP (wood pulp) beaten in 500 ml CSF was added to the water in the pulper dispersion tank and dispersed for 10 minutes. A wood pulp dispersion was prepared by adding 1% by mass of polyamide epichlorohydrin resin (manufactured by Arakawa Chemical Industries, trade name: Arafix (registered trademark) 100) as a wet paper strength enhancer to the wood pulp.

[Production of non-woven fabrics 1 to 10]
Nonwoven fabrics 1 to 10 were produced using a circular net paper machine. The wood pulp dispersion is sent to the storage tank so as to have a mixing ratio shown in Table 1, and a 20-fold diluted solution of black dye (manufactured by Nippon Kayaku, trade name: Kayafect (registered trademark) Black S Liquid) is used. Was put into a storage tank so as to have the content shown in FIG. 1 and stirred for 10 minutes together with the wood pulp dispersion. Next, the synthetic fiber dispersion was fed to the storage tank and mixed so that the mixing ratio shown in Table 1 was obtained. The mixed dispersion is fed to the paper making head so as to have the basis weight shown in Table 1, and after pressing the wet paper web, it is pressed against a Yankee dryer surface at 130 ° C. and dried. 10 was obtained.

[Production of non-woven fabrics 11 to 19]
Nonwoven fabrics 11 to 19 were produced using a circular net paper machine. The synthetic fiber dispersion and the wood pulp dispersion were sent to a storage tank and mixed so as to have a mixing ratio shown in Table 1. The mixed dispersion is fed to the paper making head so as to have the basis weight shown in Table 1. After the wet paper web is made, pressing is performed, and it is applied to the Yankee dryer surface and dried to obtain nonwoven fabrics 11 to 19 shown in Table 1. It was.

[Production of Nonwoven Fabrics 20-23 and 28-29]
Nonwoven fabrics 20-23 and 28-29 were produced using a combination paper machine in which an inclined wire paper machine and a circular net paper machine were installed on-line. First, the wood pulp dispersion liquid is sent to the storage tank for the first layer (for the inclined wire type paper machine) so as to have the mixing ratio shown in Table 1, and the black dye (made by Nippon Kayaku, trade name: Kayafect) (Registered trademark) Black S Liquid) was diluted 20 times into the storage tank so as to have the content shown in Table 1, and stirred for 10 minutes. Subsequently, the synthetic fiber dispersion was fed to the storage tank for the first layer (for the inclined wire type paper machine) so as to have a mixing ratio shown in Table 1, and mixed. Separately, the synthetic fiber dispersion and the wood pulp dispersion were mixed in a storage tank for the second layer (for a circular net paper machine) so as to have a mixing ratio shown in Table 1. The mixed dispersions are sent to the first paper head (inclined wire type paper machine) and the second paper machine head (circular paper machine), respectively, so that the basis weight shown in Table 1 is reached, and the paper is combined in the wet paper web state. After that, it was pressed and dried so that the surface of the second layer hit the Yankee dryer surface, and nonwoven fabrics 20 to 23 and 28 to 29 in which the two layers shown in Table 1 were laminated were obtained.

[Production of non-woven fabrics 24-27]
Nonwoven fabrics 24-27 were manufactured using a combination paper machine in which an inclined wire type paper machine and a circular net paper machine were installed online. Synthetic fiber dispersion and wood pulp dispersion are stored in storage tanks for the first layer (for inclined wire type paper machines) and for the second layer (for circular net paper machines) so that the mixing ratio shown in Table 1 is obtained. Feed mixed. The mixed dispersions are sent to the first paper head (inclined wire type paper machine) and the second paper machine head (circular paper machine), respectively, so that the basis weight shown in Table 1 is reached, and the paper is combined in the wet paper web state. After that, it was pressed and dried so that the surface of the second layer was in contact with the Yankee dryer surface, and nonwoven fabrics 24 to 27 in which the two layers shown in Table 1 were laminated were obtained.

[Manufacture of wallpaper sheet]
<Examples 1-9>
The nonwoven fabric 1-9 was used as it was, and it was set as the wallpaper sheet of Examples 1-9.

<Comparative Examples 1-10>
The nonwoven fabric 10-19 was used as it was, and it was set as the wallpaper sheet of Comparative Examples 1-10.

[Evaluation]
The sheet | seat for wallpaper obtained in Examples 1-9 and Comparative Examples 1-10 was evaluated by the following method. The wallpaper sheet was evaluated on the surface side unless otherwise specified, with the surface being the non-woven Yankee dryer surface.

[Brightness on the back side]
Five sheets of wallpaper sheets are stacked with the back side up, and the lightness L ^* of the back side of the top wallpaper sheet is measured with a spectrocolorimeter (SpectroEye (registered trademark) manufactured by X-Rite) with D50. The measurement was performed under conditions of a light source and a 2-degree visual field. The results are shown in Table 2.

[Lightness on the front side]
5 sheets of wallpaper sheets are stacked with the surface side up, and the lightness L ^* of the surface side of the top wallpaper sheet is measured with a spectrocolorimeter (SpectroEye (registered trademark) manufactured by X-rite) with D50. The measurement was performed under conditions of a light source and a 2-degree visual field. The results are shown in Table 2. If the lightness L ^* on the front side is less than 60, the printed pattern or white portion may feel dark.

[Concealment]
It was superimposed on the gray scale for concealment of JIS A 6921 and evaluated according to the following criteria to the extent that it appeared transparent according to JIS A 6921. The results are shown in Table 2.
(Double-circle): It does not appear (equivalent to the 4th class by the judgment of JIS A6921).
○: Appears very slightly (corresponding to the third grade).
Δ: Slightly manifested (equivalent to the second grade).
X: Appear clearly (corresponds to the first grade).
In addition, ◎ and ○ are levels with no problem, and Δ is almost no problem in practical use, but when pasted on a very dirty wall, it is a level where the dirt may be seen through.

[Opacity]
The opacity (%) was measured in accordance with JIS P 8149 using a spectroscopic color difference meter PF-10 manufactured by Nippon Denshoku. A larger opacity value is preferable because the concealability becomes higher, and the opacity is particularly preferably 80% or more. The results are shown in Table 2.

[Printability]
The flexographic printing was continuously performed at 1000 m, and the flexographic printing plate was visually checked for contamination according to the following criteria. The results are shown in Table 2.
A: Almost no dirt is observed.
Δ: Slight dirt is observed, but printing is not hindered.
X: The flexographic printing plate becomes dirty so as to hinder printing.

[Processability: Embossing]
Passing at a speed of 1 m between a 300 mm depth heated to 120 ° C and a 0.4 mm square engraved roll and a paper roll, pressurizing with a pressure of 200 MPa, and then passing through a cooling roll for embossing It was. The thickness before and after the embossing was measured with a dial gauge thickness gauge (PURICOCK PURIHT DIAL GAUGE (0.001 × 2 mm), No. 25, measuring element 5 mmφ flat type), and the embossing rate was obtained by the following formula. . Moreover, the same measurement was performed 5 times about the same sample and the average value of the obtained embossing rate was made into the embossing rate of the said sample. The embossing rate is preferably 10.0% or more. The results are shown in Table 2.

Embossing rate (%): {(d−d0) / 300} × 100
d: Thickness after embossing (μm)
d0: Thickness before embossing (μm)
Engraving depth: 300 μm

[Manufacture of wallpaper sheet]
<Examples 10 to 13>
The nonwoven fabric 20-23 which is a nonwoven fabric in which two layers are laminated and the coloring material is contained in the layer on the back side of the wallpaper sheet is used as it is to obtain a wallpaper sheet of Examples 10-13.

<Comparative Examples 11-14>
The nonwoven fabrics 24-27 which are the nonwoven fabrics which laminated | stacked two layers were used as it was, and it was set as the sheet | seat for wallpaper of Comparative Examples 11-14.

[Evaluation]
The wallpaper sheets obtained in Examples 10 to 13 and Comparative Examples 11 to 14 were evaluated in the same manner as in Examples 1 to 9 and Comparative Examples 1 to 13. The results are shown in Table 3.

[Manufacture of wallpaper sheet]
<Examples 14 to 20>
37 parts of water, 20 parts of 50% water-soluble resin (DISPERBYK-190 manufactured by Big Chemie Japan), 3 parts of isopropyl alcohol, 40 parts of blue dye (manufactured by Nippon Kayaku, trade name: Kayafect (registered trademark) Blue RF Liquid) Was gradually added and kneaded to prepare an ink. This ink was printed on the entire back surface of the nonwoven fabrics 11 to 17 using a test gravure printing machine to obtain wallpaper sheets of Examples 14 to 20. In addition, the adhesion amount of the blue dye (coloring material) measured from the light absorption density was 0.7 to 1.2 g / m ² .

<Examples 21 to 27>
Mix 57 parts of water, 25 parts of glycerin and 3 parts of dipropylene glycol-n-propyl ether, and gradually add 15 parts of blue dye (manufactured by Nippon Kayaku, trade name: Kayafect (registered trademark) Blue RF Liquid). After stirring for 1 hour, the mixture was filtered through a membrane filter having a pore size of 1 μm and diluted with water to obtain a coating solution having a blue dye content of 5%. Using a gravure coater so that the solid content coating amount was 2 g / m ² , coating was performed on the entire back surface of the nonwoven fabrics 11 to 17 to obtain wallpaper sheets of Examples 23 to 27.

<Examples 28 to 29>
57 parts of water, 20 parts of 50% water-soluble resin (DISPERBYK-190 manufactured by Big Chemie Japan), 3 parts of isopropyl alcohol, 20 parts of blue dye (manufactured by Nippon Kayaku, trade name: Kayafect (registered trademark) Blue RF Liquid) Was gradually added and kneaded to prepare an ink. This ink was printed on the entire back surface of the nonwoven fabric 28-29 using a test gravure printing machine to obtain wallpaper sheets of Examples 28-29. In addition, the adhesion amount of the blue dye (coloring material) measured from the light absorption density was 0.4 to 0.6 g / m ² .

<Examples 30 to 31>
Mix 57 parts of water, 25 parts of glycerin and 3 parts of dipropylene glycol-n-propyl ether, and gradually add 15 parts of blue dye (manufactured by Nippon Kayaku, trade name: Kayafect (registered trademark) Blue RF Liquid). After stirring for 1 hour, the mixture was filtered through a membrane filter having a pore size of 1 μm and diluted with water to obtain a coating solution having a blue dye content of 2.5%. Using a gravure coater so that the solid content coating amount was 1 g / m ² , coating was performed on the entire back surface of the nonwoven fabrics 28 to 29 to obtain wallpaper sheets of Examples 30 to 31.

<Comparative Examples 15-16>
The non-woven fabric 28-29, which is a non-woven fabric in which two layers are laminated and the coloring material is contained in the layer on the back side of the wallpaper sheet, was used as the wallpaper sheet of Comparative Examples 15-16.

[Evaluation]
The wallpaper sheets obtained in Examples 14 to 31 and Comparative Examples 15 to 16 were evaluated in the same manner as in Examples 1 to 13 and Comparative Examples 1 to 14. The results are shown in Table 4.

From comparison between Examples 1-9 and Comparative Examples 2-10, by setting the lightness L ^* to 30-80, a wallpaper sheet with high concealability can be obtained. In Comparative Example 1, the concealability was high, but the white part was dark. Further, as is clear from Comparative Example 9, if the wood pulp does not contain, the printability is poor. In addition, the comparative example 10 which consists of 100% of wood pulp did not have the texture as a wallpaper.

  Moreover, by comparison with Examples 10-13 and Comparative Examples 11-14, it is the nonwoven fabric which laminated | stacked two layers, and by using the nonwoven fabric which contained the coloring material in the layer used as the back surface side of this sheet | seat for wallpaper. However, a highly concealable wallpaper sheet could be obtained. Further, from comparison between Examples 3 and 7 and Examples 10 and 11, a non-woven fabric in which two layers were laminated and a non-woven fabric containing a coloring material in the layer on the back side of the wallpaper sheet was used. However, since the lightness on the front surface side is higher than that on the back surface side, it is possible to further suppress the influence of the printed pattern on the front surface and the white part.

  In addition, from Examples 14 to 27, a wallpaper sheet having high concealability could be obtained by printing or coating an ink or a coating liquid containing a color material on the back surface side. Moreover, from the comparison with Examples 1, 3, 5 to 8 and Examples 14 to 20 and Examples 21 to 27, it is better to print or apply the ink or coating liquid containing the color material on the back side. Since the brightness on the front surface side is higher than that on the back surface side, it is possible to further suppress the influence of the printed pattern on the front surface and the white part.

Further, from comparison between Examples 28 to 29 and Comparative Examples 15 to 16, the lightness L ^{* of} the nonwoven fabric obtained by laminating two layers and containing a coloring material in the layer on the back side of the wallpaper sheet ^. Even when the value exceeds 80, it is possible to obtain a wallpaper sheet having high concealability by printing or coating an ink or a coating liquid containing a color material on the back side.

  The wallpaper sheet of the present invention can be suitably used as an interior member used in a house or the like.

Claims (3)

A wallpaper sheet comprising a nonwoven fabric containing wood pulp and synthetic fibers, wherein the lightness L ^* on the back side of the wallpaper sheet is 30 to 80.   The wallpaper sheet according to claim 1, wherein the wallpaper sheet is a nonwoven fabric in which at least two layers are laminated, and a color material is contained in a layer on the back side of the wallpaper sheet.   The wallpaper sheet according to claim 1 or 2, wherein an ink or a coating liquid containing a coloring material is printed or coated on the back side of the wallpaper sheet.