JP2008261069A - Foamed wall paper - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a foamed wallpaper excellent in followability to surface irregularity by embossing and stain-proofness to staining materials such as a water-based pen and an oil-based pen, and electric discoloration and the like, and excellent in installability and production safety without using vinyl chloride resins. <P>SOLUTION: The foamed wallpaper has at least a foamed resin layer, a film layer and a surface-protection layer laminated on a substrate in order, wherein the resin layer comprises a foamed resin layer and a non-foamed resin layer, and the surface-protection layer is formed by crosslinking and hardening an ionizing radiation-curable resin composition. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to foam wallpaper.

  Architectural interior materials such as wallpaper are required to be flame retardant as a performance from the viewpoint of safety against fire, and a certain level of flame retardancy is often required by the Building Standard Law. In addition, the architectural interior material is required to have excellent design properties in order to enhance the comfort as an indoor living space. As a technique for imparting excellent design properties to wallpaper, a three-dimensional effect is imparted to the design. In this case, it is advantageous to use not only flexibility but also a material that can be highly foamed. As a material that meets these requirements, there is a material in which a pattern layer is provided by printing on a vinyl chloride resin layer, or a material in which an uneven pattern is formed by foaming and embossing the vinyl chloride resin layer. Widely used. However, these wallpapers have a problem that the stain resistance and surface strength are not sufficient. This is because the wallpaper is made of a vinyl chloride resin having a problem of contamination and the like, and for the purpose of improving workability and design, it is applied to the surface of the wallpaper by forming a foam or a concavo-convex pattern. This is because fine irregularities and voids are generated.

  In order to solve such problems, a method of providing a surface protective layer on the surface of the wallpaper to improve surface properties such as stain resistance, for example, applying urethane or acrylic resin to the surface of the wallpaper A method for forming a surface protective layer is employed. However, when the surface protective layer provided in this way is processed to form foam or a concavo-convex pattern, the surface protective layer cannot follow the foam or the concavo-convex pattern, resulting in uneven thickness. This causes problems in manufacturing stability such as cracking and exposure of the foam layer.

  Further, the surface protective layer of the wallpaper having a foamed resin layer made of a thermoplastic resin containing a foaming agent is a film excellent in stain resistance on the surface of the wallpaper, such as an acrylic resin film, a polyurethane resin film, a fluorine-based film. There has been proposed a method in which a resin film, an ethylene-vinyl alcohol copolymer film, or the like is bonded with an adhesive or the like (for example, Patent Documents 1 and 2). However, just using these films as a surface protective layer is insufficient from the viewpoint of stain resistance, and further improvements are desired.

On the other hand, in recent years, foamed wallpaper not using vinyl chloride resin, which has been used preferably from the viewpoint of flexibility, workability, and cost, has been developed in consideration of the environment. A foamed wallpaper (non-vinyl chloride resin wallpaper) used has been proposed (Patent Document 3). In general, a foamed wallpaper (non-vinyl chloride resin wallpaper) using a polyolefin resin has a feature that it is inferior to a PVC resin wallpaper in terms of surface strength. The foamed wallpaper showed the same performance as the PVC resin wallpaper in terms of surface strength. However, the embossed surface was not smooth, water pollutants such as water pens and oil pens, power supplies such as refrigerators and air conditioners. There has been a problem that the fine dust derived from carbon in the air is attracted by static electricity in the vicinity of the cord, and is not sufficient in terms of resistance to contamination caused by electricity and burns.
In addition, these wallpapers can be easily curled after application of glue at the time of construction, or open after the construction, wrinkles are noticeable after the wallpaper is applied, or wallpaper that has become old when the wallpaper is replaced There is a problem of workability that makes it difficult to install a new wallpaper because the peeling interface varies even if it is peeled off, and a problem of production safety that suppresses the generation of static electricity when manufacturing the wallpaper. .

JP 2001-260287 A JP 2001-260261 A JP 2006-97210 A

  Under such circumstances, the present invention is excellent in uneven followability by embossing, contamination resistance such as water-based pens and oil-based pens, contamination resistance against electric burns, etc., and excellent workability and production safety. Another object of the present invention is to provide a foam wallpaper that does not use a vinyl chloride resin.

  As a result of intensive studies to achieve the above object, the present inventors have a specific layer structure including a surface protective layer, and the surface protective layer is obtained by crosslinking and curing an ionizing radiation curable resin composition. By using the vinyl chloride resin, which has excellent conformability by embossing, excellent contamination resistance to water pollutants such as water-based pens and oil-based pens, electricity burns, etc., and has excellent workability and production safety. Could not get foam wallpaper.

That is, the present invention
(1) A wallpaper in which at least a resin layer, a film layer, and a surface protective layer are laminated in order on a substrate, the resin layer comprising a foamed resin layer and a non-foamed resin layer, and the surface protective layer is ionizing radiation Foamed wallpaper obtained by crosslinking and curing a curable resin composition;
(2) The foamed wallpaper according to (1) above, wherein the resin layer is laminated from the base material side in the order of the non-foamed resin layer and the foamed resin layer,
(3) The foamed wallpaper according to (1) above, wherein the resin layer is laminated from the base material side in the order of the non-foamed resin layer, the foamed resin layer, and the non-foamed resin layer.
(4) The foamed wallpaper according to any one of (1) to (3), wherein the surface protective layer has a surface tension of 30 dyne / cm or less.
(5) The foamed wallpaper according to any one of (1) to (4), wherein the ionizing radiation curable resin composition contains silicone (meth) acrylate.
(6) The above (1) to (5), wherein the resin constituting the foamed resin layer contains at least one of ethylene-vinyl acetate copolymer (EVA) and ethylene-methyl methacrylate copolymer (EMMA). Foam wallpaper according to any of the
(7) The foamed wallpaper according to any one of the above (1) to (6), wherein the resin constituting the non-foamed resin layer is a polyolefin resin,
(8) The foamed wallpaper according to (7), wherein the polyolefin-based resin contains at least one of ethylene-vinyl acetate copolymer (EVA) and ethylene-methyl methacrylate copolymer (EMMA),
(9) The foamed wallpaper according to any one of the above (1) to (8), wherein the substrate is a single glossy backing paper having a surface smoothness measured in accordance with JIS P8119 of 40 seconds or less.
(10) The foamed wallpaper according to (9) above, wherein the glossiness of the single glossy backing paper is 1.2% or less,
(11) The foamed wallpaper according to any one of (1) to (8), wherein the base material is a backing material having an interlayer strength of 12 to 40 N / m.
(12) The foamed wallpaper according to any one of (1) to (8) above, wherein the base material is a backing material having a Clark stiffness of 75% or less, and (13) mechanically embossed from the surface protective layer side. The foamed wallpaper according to any one of (1) to (12),
Is to provide.

  According to the present invention, there is provided a vinyl chloride resin that is excellent in uneven followability by embossing, and is excellent in contaminants such as water-based pens and oil-based pens, stain resistance against electric burns, etc., and in workability and production safety. A foam wallpaper that is not used can be provided.

  A typical structure of the foam wallpaper of the present invention will be described with reference to FIGS. FIG.1 and FIG.2 is a schematic diagram which shows the cross section of the foam wallpaper 1 of this invention. In the example shown in FIGS. 1 and 2, the foamed wallpaper 1 of the present invention includes a resin layer 3 (in the case of FIG. 1, a non-foamed resin layer 31 and a foamed resin layer 32 in the case of FIG. In this case, the non-foamed resin layer 31A, the foamed resin layer 32, and the non-foamed resin layer 31B), the pattern layer 4, the adhesive layer 5, the film layer 6, the primer layer 7, and the ionizing radiation curable resin composition A surface protective layer 8 formed by crosslinking and curing is sequentially laminated. And the surface of the foam wallpaper 1 is embossed from the surface protective layer 8 side, and has the uneven | corrugated pattern 10 which provides the design feeling excellent in the foam wallpaper.

[Substrate 2]
Hereinafter, the present invention will be described in detail with reference to FIGS. 1 and 2 showing one preferred embodiment of the present invention.
The base material 2 used in the present invention is not particularly limited as long as it is usually used as wallpaper. For example, backing paper, flame retardant paper, synthetic resin sheet, woven fabric, non-woven fabric, knitted fabric and the like are used depending on the application. It can be selected appropriately. Among them, ordinary wallpaper such as pulp-based flame retardant paper impregnated with water-soluble flame retardants such as guanazine sulfanilate and guanazine phosphate, inorganic paper mixed with inorganic agents such as calcium carbonate, aluminum hydroxide and magnesium hydroxide For example, a backing paper or a backing material using the same is preferably used. From the viewpoint of curling prevention, the backing paper preferably has an underwater elongation of 2% or less, and more preferably 1.8% or less. Incidentally, the elongation in water is determined by the JAPAN TAPPI paper pulp test method No. It is a value measured according to 27: 2000.

These materials may each be used alone, but may be a laminate of any combination, such as a composite of paper, flame retardant, inorganic agent, dry paper strength enhancer, if necessary, A wet paper strength enhancer, a colorant, a sizing agent, a fixing agent, and the like may be appropriately added.
The thickness of the substrate 2 is not particularly limited, but the weight is about 50 to 300 g / m ² , preferably 55 to 160 g / m ² . In particular, a range of 60 to 160 g / m ² is preferable in order to pick up the unevenness of the groundwork during the construction of the wallpaper and make the so-called unevenness inconspicuous.

[Substrate 2: Single glossy backing paper]
As the base material 2, glossy backing paper having a surface smoothness measured according to JIS P8119 of 40 seconds or less is preferably used from the viewpoint of production stability and production safety. Here, it shows that surface smoothness is so high that surface smoothness is large. In addition, the glossy backing paper preferably has an underwater elongation of 1.5% or less, more preferably 1.2% or less, from the viewpoint of curling prevention.

  This glossy backing paper is produced by drying using a Yankee dryer in the paper making process. The single glossy backing paper is dried by copying the surface of a Yankee dryer having a smooth surface while the paper sheet is stretched, so that one side has a very high surface smoothness. When the glossy backing paper obtained in this way is used for wallpaper, even when paste is applied at the time of wallpaper construction, the wallpaper is hardly curled. This is presumably because the glossy backing paper is dried in the stretched state and does not stretch even when the glue is applied.

The single glossy backing paper is preferably made from wood pulp, but non-wood pulp, organic synthetic fibers, inorganic fibers, etc. other than wood pulp can also be used. In addition, a flame retardant, an inorganic agent, a dry paper strength enhancer, a wet paper strength enhancer, a colorant, a sizing agent, a fixing agent, and the like may be added as appropriate within the range in which the effects of the present invention are not impaired.
The drying conditions by the Yankee dryer are not particularly limited, but generally, a wet paper sheet having a moisture content of 30 to 70% by mass is brought into contact with a Yankee dryer shell at 80 to 140 ° C., and the moisture content is 3 to 10%. It is preferable to dry until about%.
When single glossy backing paper is used as the base material of the foam wallpaper of the present invention, the foamed resin layer, etc., which is the upper layer portion thereof, is provided on either side of the single glossy backing paper without limitation, but has no gloss It is preferable to provide an upper layer portion on the surface because the amount of paste applied can be reduced.

[Base Material 2: Backing Material-1]
As the substrate 2, a backing material-1 having an interlayer strength of 12 to 40 N / m is also preferably used. The interlayer strength of the backing material is preferably 12 to 25 N / m, more preferably 12 to 20 N / m. If the interlaminar strength of the backing material is within the above range, the wallpaper can be satisfactorily adhered without applying the glue to the wallpaper and pulling it when the wallpaper is applied. Further, the peeling of the wallpaper tends to occur between the layers of the backing material, and the peeling interface does not vary during peeling. Thus, the workability at the time of pasting a new wallpaper is improved.

  As the material of the backing material-1, the above-mentioned backing paper can be preferably used. Further, the backing material-1 preferably has an underwater elongation of 1.5% or less, and more preferably 1.2% or less, from the viewpoint of curling prevention.

The interlayer strength is measured by the following method.
A 30 mm wide kraft tape (manufactured by Sekisui Chemical Co., Ltd.) is attached to both sides of the foamed wallpaper, and cut into a length of 250 mm and a width of 15 mm to obtain a test piece. When measuring the interlaminar strength in the vertical direction, create a test piece in the vertical eye, and when measuring the interlaminar strength in the horizontal direction, create a test piece in the horizontal eye. Next, the kraft tape is pulled, and the peeling behavior of the test piece is visually evaluated. As a machine for pulling the kraft tape, a testing machine stipulated in JIS P-8113 (paper and paperboard tensile strength test method) is used.

There are various methods for controlling the interlaminar strength of the backing material, and it can be performed by control by a papermaking method, control by beating, control of the addition amount of a dry paper strength enhancing resin, or the like. More specifically, as control by the papermaking method, for example, the interlayer strength can be weakened by using paper made by a double-side dehydration method using a twin wire papermaking machine as backing paper. Beating also increases the density of the sheet and reduces the space in which the fibers can stretch, thereby increasing the bond between the fibers. Therefore, it is possible to weaken the interlayer strength by relaxing the beating condition and reducing the number of times. In addition, an acrylamide resin or the like is usually added to enhance the dry paper strength, but the interlayer strength can be weakened by reducing this content. In addition, the control by the addition amount of the dry paper strength-enhancing resin is less than the control by beating, the physical properties of the substrate such as the decrease in the amount of fine fibers generated, the property such as porosity, the ratio of the strength to the apparent specific gravity, etc. It is suitable without changing.
By combining these control methods, the interlayer strength of the backing material can be controlled within the above-mentioned preferable range.

[Substrate 2: backing material-2]
As the base material 2, a backing material-2 having a Clark stiffness of preferably 75% or less, more preferably 70% or less is also preferably used. If the Clark stiffness of the backing material is within the above range, the occurrence of creases during construction can be suppressed. Here, the measurement of Clark stiffness is based on JIS P-8143.

  As the material of the backing material-2, the above-mentioned backing paper can be preferably used. Further, the backing material-2 preferably has an underwater elongation of 1.5% or less, and more preferably 1.2% or less, from the viewpoint of curling prevention.

Methods for controlling the Clark stiffness of the backing material include a method of controlling the thickness of the backing material, the degree of pulp beating, and the fiber length of the pulp. Since the stiffness of the paper tends to increase in proportion to the cube of the thickness of the paper when the basis weight is constant, a method of adjusting the thickness of the paper is effective. Beating also increases stiffness by increasing the density of the sheet and reducing the space in which the fibers can stretch, thereby increasing the bond between the fibers. Therefore, Clark stiffness can be weakened by loosening the beating condition and reducing the number of times. Further, regarding the fiber length of the pulp, the short fiber pulp paper tends to be more stiff than the long fiber pulp paper. Therefore, the Clark stiffness can be reduced by selecting a longer fiber pulp paper.
By combining these control methods, the Clark stiffness of the backing material can be controlled within the range specified by the present invention.

[Resin layer 3]
The resin layer 3 includes a non-foamed resin layer 31 and a foamed resin layer 32, imparts flame retardancy to the foamed wallpaper of the present invention, and the ink composition used for the pattern layer 4 passes through the foamed resin layer 32. It is a layer provided for the purpose of suppressing permeation into the substrate 2.
As long as the resin layer 3 includes a non-foamed resin layer and a foamed resin layer, the form thereof is not particularly limited. For example, the non-foamed resin layer and the foamed resin layer may be laminated on the substrate 2 in this order, The layers may be laminated in the order of the non-foamed resin layer, or may have a configuration of three or more layers laminated in the order of the non-foamed resin layer, the foamed resin layer, and the non-foamed resin layer. Especially, from a viewpoint of improving the adhesive force of a foamed resin layer and a base material, what laminates | stacks the resin layer 3 in order of a non-foamed resin layer and a foamed resin layer from the base material side is preferable. In addition, as shown in FIG. 2, the resin layer 3 is preferably laminated in the order of the non-foamed resin layer, the foamed resin layer, and the non-foamed resin layer from the base material side from the viewpoint of manufacturing stability.

[Non-foamed resin layer 31]
The non-foamed resin layer 31 improves the adhesive force between the foamed resin layer 32 and the base material 2, and the ink composition used for the pattern layer 4 penetrates into the base material 2 through the foamed resin layer 32. It is a layer provided for the purpose of suppression. The non-foamed resin layer 31 is provided between the base material 2 and the foamed resin layer 32, that is, the resin layer 3 is preferably laminated in the order of the non-foamed resin layer and the foamed resin layer from the base material side. A plurality of non-foamed resin layers may be provided, for example, the resin layer 3 may be laminated in the order of the non-foamed resin layer, the foamed resin layer, and the non-foamed resin layer from the substrate side. In this case, the plurality of non-foamed resin layers may be the same or different. The same applies when there are a plurality of foamed resin layers.

[Non-foamed resin layer 31: resin]
The resin constituting the non-foamed resin layer 31 is not particularly limited, but a thermoplastic resin such as a polyolefin resin, a methacrylic resin, a thermoplastic polyester resin, a polyvinyl alcohol resin, a fluorine resin, etc. A coalesced resin can be mentioned, and among these, polyolefin resins are preferred.
Examples of the polyolefin-based resin include, for example, polyolefins such as polyethylene, polypropylene, polybutene, polybutadiene, polyisoprene, and various copolymers, copolymers of α-olefins having 4 or more carbon atoms (linear low density polyethylene), ethylene- Acrylic acid copolymer, ethylene-methyl acrylate copolymer, ethylene-ethyl acrylate copolymer, ethylene-methacrylic acid copolymer such as ethylene-methacrylic acid copolymer, ethylene-vinyl acetate copolymer Examples thereof include a polymer (EVA), a saponified ethylene-vinyl acetate copolymer or ionomer, or a mixed resin composed of one or more of these. Among these, at least one of ethylene-vinyl acetate copolymer (EVA) and ethylene-methyl methacrylate copolymer (EMMA) is particularly preferable. EVA and EMMA are not particularly limited, and known or commercially available products can be used. In particular, EVA preferably has a vinyl acetate component (VA component) of 15 to 30% by mass. Moreover, as for EMMA, what a methyl methacrylate component (EMA component) is 15-30 mass% is preferable.

[Non-foamed resin layer 31: other resin]
In this invention, other resin other than said resin may be contained as a resin component. For example, polyethylene, ethylene-propylene copolymer, ethylene-butene-1 copolymer, polypropylene, propylene-butene-1 copolymer, polybutene-1, butene-1, propylene-ethylene-3 terpolymer, butene In addition to -1-hexene-1-octene-1-element copolymer and polymethylpentene, olefin-based elastomers described in JP-A-6-16832, JP-B-6-23278 and the like can also be used. . These resins can be used alone or in combination of two or more.

[Non-foamed resin layer 31: various additives]
Moreover, the non-foamed resin layer 31 can contain various additives as required. For example, an inorganic filler can be added to give an increase effect, or a flame retardant can be added to give flame retardancy. Moreover, when bridge | crosslinking, the crosslinking adjuvant used with a foamed resin layer can also be mix | blended.
Examples of the inorganic filler include powders (particles) such as calcium carbonate, barium sulfate, clay and talc, and inorganic hollow bodies such as mica, silica, alumina, diatomaceous earth, silica sand, and shirasu balloon.

  Suitable flame retardants include, for example, nitrogen compounds such as urea, hydroxides such as magnesium hydroxide and aluminum hydroxide (particularly compounds having crystal water), flame retardants containing self-extinguishing phosphorus or halogen elements, and the like. Yes. In particular, by blending a compound such as a hydroxide, flame retardancy can be achieved by the heat of vaporization of crystal water during combustion decomposition. Moreover, it is preferable when the mixed flame retardant compound which consists of a nitrogen compound and a phosphorus compound is mix | blended 25-100 mass parts with respect to 100 mass parts of polyolefin resin. This is because the compatibility with polyolefin is good and the thermal stability is also good.

Various rubbers may be added for the purpose of imparting flexibility, impact resistance, and easy adhesion to the polyolefin resin.
Examples of rubbers include diene rubbers, hydrogenated diene rubbers, and olefin elastomers. Among these, hydrogenated diene rubber is preferable. The hydrogenated diene rubber is obtained by adding a hydrogen atom to at least a part of a double bond of a diene rubber molecule, and is used as a modifier for a polyolefin resin in the present invention. There is a role to suppress the crystallization of the polyolefin resin and increase the flexibility and transparency. In general, when a diene rubber is added to a polyolefin resin, the weather resistance and heat resistance are lower than those of a polyolefin resin without the addition of a diene rubber due to the double bond of the diene rubber. Since the double bond is saturated with hydrogen, the weather resistance and heat resistance of the polyolefin resin are not deteriorated, and the double bond is satisfactory.

Examples of the diene rubber include isoprene rubber, butadiene rubber, butyl rubber, propylene / butadiene rubber, acrylonitrile / butadiene rubber, acrylonitrile / isoprene rubber, and styrene / butadiene rubber. For the purpose of the present invention, styrene-butadiene rubber and the like are particularly preferable.
Although it does not specifically limit as addition amount of rubber | gum, Usually, what is necessary is just to be about 1-90 mass parts with respect to 100 mass parts of polyolefin resin.

  Moreover, the method of adding a pigment and performing transparent coloring or opaque coloring is mentioned. As the pigment, known or commercially available pigments can be used without limitation. For example, titanium white, zinc white, petal, vermilion, ultramarine blue, cobalt blue, titanium yellow, yellow lead, carbon black and other inorganic pigments, isoindolinone, Hansa Yellow A, quinacridone, permanent red 4R, phthalocyanine blue, indanthrene Examples include organic pigments (including dyes) such as Brie RS and aniline black, metallic pigments such as aluminum and brass, pearlescent pigments made of foil powder such as titanium dioxide-coated mica and basic lead carbonate, and the like. These can select either a transparent colored pigment or an opaque colored pigment depending on the application. These pigments may be added and dispersed as powder or scaly foil pieces.

[Formation of non-foamed resin layer 31]
The non-foamed resin layer 31 is obtained by, for example, emulsifying a non-foamed resin composition containing the above resin or the like into an emulsion composition, or by pelletizing a non-foamed resin composition by a comma coater method or a T-die. It can be formed by a known method such as a film method, a calendering method, or a dry lamination method using an adhesive. Here, emulsification can be performed by a usual method. For example, the emulsion composition is obtained by emulsifying the thermoplastic resin in the non-foamed resin composition by an emulsion polymerization method or the like, and then adding a predetermined amount of other components. Can be obtained.

The non-foamed resin composition may be subjected to a crosslinking treatment for the purpose of improving the surface characteristics. The method for the crosslinking treatment is not limited, but crosslinking treatment (curing treatment) with ionizing radiation is preferable. For example, a layer made of the non-foamed resin composition is formed on a base material, and cross-linked by irradiating with ionizing radiation such as an electron beam in order to widen the temperature range of the foamable clay. Thereby, productivity is stabilized and the surface of the non-foamed resin layer 31 is hardened to improve surface characteristics. When the non-foamed resin composition is subjected to a crosslinking treatment, the non-foamed resin composition can preferably contain a crosslinking agent. Any crosslinking agent can be used without particular limitation as long as it can crosslink the resin constituting the non-foamed resin layer.
As ionizing radiation, ultraviolet rays, electron beams and the like are usually used. As the ultraviolet light source, for example, a light source such as an ultrahigh pressure mercury lamp, a high pressure mercury lamp, a low pressure mercury lamp, a carbon arc, a black light lamp, or a metal halide lamp can be used. Further, as the electron beam source, for example, various electron beam accelerators such as a Cockloft Walton type, a pandegraph type, a resonant transformer type, an insulating core transformer type, a linear type, a dynamitron type, and a high frequency type may be used. The irradiation dose is usually selected in the range of 5 to 300 kGy (0.5 to 30 Mrad), preferably 10 to 50 kGy (1 to 5 Mrad).
The thickness of the non-foamed resin layer 31 is preferably 5 to 25 μm, more preferably 20 to 40 μm, for the purpose of obtaining excellent surface characteristics and ensuring the unevenness followability of the wallpaper by embossing.

The non-foamed resin layer 31 may be a transparent or opaque commercially available film made of the above resin. Commercially available films include polyolefin resin films, polyolefin resins coated with urethane or acrylic coating agents, ethylene-vinyl alcohol copolymer resin films, polyvinyl fluoride, polyvinylidene fluoride, ethylene tetrafluoroethylene, etc. And a film such as a fluororesin film. Among them, polyolefin resin is preferable, and it has excellent performance such as stain resistance, scratch resistance, chemical resistance, etc., and has excellent uneven followability in embossing, that is, the longitudinal tensile elongation is sufficiently large, and ionizing radiation. The ethylene-vinyl alcohol copolymer resin film is particularly preferred because it does not disintegrate and is low in production cost and low in smoke concentration during combustion.
When a commercially available film is used for the non-foamed resin layer 31, the thickness is preferably 5 to 25 μm, and more preferably 20 to 40 μm. If the thickness of the film is within the above range, it is possible to obtain excellent surface characteristics without being restricted in the production of the film, and to ensure unevenness of the wallpaper by embossing.

[Foamed resin layer 32]
The foamed resin layer 32 is provided for imparting flame retardancy to the wallpaper, and preferably a foamed resin composition comprising a thermoplastic resin containing a foaming agent, an inorganic filler, and other various additives as required. It is a layer obtained by foaming a product.

[Foamed resin layer 32: thermoplastic resin]
Examples of the thermoplastic resin include polyethylene, propylene, polystyrene, ethylene-vinyl acetate copolymer resin (EVA), polyolefin resins such as ethylene- (meth) acrylic acid resin, acrylonitrile-butadiene-styrene copolymer (ABS resin). ), Acrylonitrile-styrene copolymer, nylon, polyacetal resin, acrylic resin, polycarbonate resin, polyester resin, polyvinyl acetate resin, polyvinyl alcohol resin, polyurethane resin, polyvinyl chloride resin, etc. A thermoplastic resin simple substance and a copolymer, or these mixed resins can be mentioned. Of these, polyolefin resins are preferred from the viewpoint of environmental protection, and ethylene-vinyl acetate copolymer resins (EVA) and ethylene- (meth) acrylic acid resins are more preferred, and ethylene-vinyl acetate copolymers. It is more preferable to use at least one of resin (EVA) and ethylene-methyl methacrylate copolymer resin (EMMA).

[Foamed resin layer 32: foaming agent]
Examples of foaming agents include inorganic foaming agents such as sodium bicarbonate, sodium carbonate, ammonium bicarbonate, ammonium carbonate, and ammonium nitrite, N, N′-dimethyl-N, N′-dinitrosotephthalamide, N, N′-di Nitroso compounds such as nitrosopentamethylenetetramine, azodicarbonamide, azobisformamide, azobisisobutyronitrile, azocyclohexylnitrile, azodiaminobenzene, azo compounds such as barium azodicarboxylate, benzenesulfonyl hydrazide, toluenesulfonyl hydrazide , P, p′-oxybis (benzenesulfonylhydrazide), sulfonylhydrazide compounds such as diphenylsulfone-3,3′-disulfonylhydrazide, calcium azide, 4,4′-diphenyldisulfoni Azide, etc. azide compounds such as p- toluenesulfonyl azide and the like. Low cost, low heat of decomposition, excellent flame retardancy and self-extinguishing properties, stable in water, non-toxic, and capable of processing heat decomposition chemical foaming agent below decomposition temperature Therefore, a thermally decomposable foaming agent of an azo compound such as azodicarbonamide or azobisformamide is preferable.

  The addition amount of the foaming agent may be appropriately determined depending on the required design properties, but is preferably 0.5 to 15 parts by mass with respect to 100 parts by mass of the thermoplastic resin constituting the foamed resin layer 32. If necessary, a foaming aid that accelerates the decomposition of the foaming agent can be used in combination in order to obtain a further foaming effect. For example, when azodicarbonamide is used as the foaming agent, zinc oxide, lead sulfate, urea, zinc stearate, or the like is used as the foaming aid.

[Foamed resin layer 32: inorganic filler]
There is no restriction | limiting in particular as the inorganic filler used for the foamed resin layer 32, A various thing can be used.
Examples of inorganic fillers include calcium carbonate, magnesium carbonate, fly ash, dehydrated sludge, natural silica, synthetic silica, kaolin, clay, calcium oxide, magnesium oxide, titanium oxide, zinc oxide, barium sulfate, calcium hydroxide, and water. Aluminum oxide, alumina, magnesium hydroxide, talc, mica, hydrotalcite, aluminum silicate, magnesium silicate, calcium silicate, calcined talc, wollastonite, potassium titanate, magnesium sulfate, calcium sulfate, magnesium phosphate, sepiolite, zonolite , Aluminum borate, silica balloon, glass flake, glass balloon, silica, iron slag, copper, iron, iron oxide, carbon black, sendust, alnico magnet, magnetic powder such as various ferrites, cement Glass powder, diatomaceous earth, antimony trioxide, magnesium oxysulfate, hydrated aluminum, hydrated gypsum, alum, and the like. Among these, aluminum hydroxide is preferable because it has a low decomposition temperature, a large endothermic amount, and low cost. These inorganic fillers can be used alone or in combination of two or more.

Many of these inorganic fillers have an effect of imparting flame retardancy to the foamed wallpaper of the present invention, and the effect is further increased when incorporated in a large amount. The amount of the inorganic additive used is preferably 100 parts by mass or more with respect to 100 parts by mass of the thermoplastic resin constituting the foamed resin layer 32 in order to obtain sufficient flame retardancy of the foamed wallpaper.
5-25 micrometers is preferable and, as for the average particle diameter of the inorganic filler used in this invention, 5-15 micrometers is more preferable.

  These inorganic fillers may be used as they are, but the inorganic fillers are previously silane-based, titanate-based, aluminate-based, zircoaluminum-based coupling agents, phosphate-based, fatty acid-based surfactants, You may process by fats and oils, wax, a stearic acid, a silane coupling agent, etc.

  The foamed resin composition constituting the foamed resin layer 32 can contain various additives depending on the required physical properties. Examples of the various additives include a fungicide, an insecticide, an antiseptic, an antibacterial agent, a diluent, a deodorant, a light stabilizer, and a plasticizer.

[Foamed resin layer 32: forming method]
The foamed resin layer 32 can be formed by the same method as that for the non-foamed resin layer 31. Moreover, it is the same as that of a non-foamed resin layer that a crosslinking process can be performed. When the extrusion film forming method using a T-die is adopted in forming the resin layer 3, the non-foamed resin layer 31 and the foamed resin layer 32 may be formed separately or simultaneously. In the case of simultaneous extrusion film formation, a multi-manifold type T die or the like that enables simultaneous formation of a plurality of layers by simultaneously forming a molten resin corresponding to each layer is used.
In addition, when an extrusion film forming method using a T die is employed for forming the foamed resin layer 32, the inorganic filler preferably contained in the foamed resin composition is likely to remain in the extrusion port (so-called die) of the extruder, Inorganic filler residues (so-called eyes and eyes) tend to become foreign matters on the sheet surface. In such a case, as described above, the resin layer 3 is preferably laminated in the order of the non-foamed resin layer, the foamed resin layer, and the non-foamed resin layer from the base material side. If the resin layer 3 has such a configuration, it is possible to suppress the occurrence of eye spots by simultaneously forming the resin layer by sandwiching the foamed resin layer between two non-foamed resin layers, and excellent manufacturing. Stability is obtained.

The foamed resin layer 32 can be foamed by a known foaming method. For example, the foamed resin layer 32 can be foamed at a temperature of about 180 to 240 ° C. using a foaming heating furnace. The foaming treatment can be performed without particular limitation as long as the foamed resin composition is formed as the foamed resin layer 32, but is usually performed after the surface protective layer is provided.
The thickness of the foamed resin layer 32 is not particularly limited and can be appropriately set according to desired characteristics and the like, but is preferably 50 to 300 μm in the film-forming state, and the thickness after foaming is preferably 350 to 1200 μm. . Further, the foaming ratio in forming the foamed resin layer is not particularly limited, but is usually about 3 to 7 times. If the expansion ratio is within the above range, good surface strength, workability and the like can be obtained.

[Picture layer 4]
The pattern layer 4 is a layer that is preferably provided in order to give decorativeness to the substrate 2, and is formed by printing various patterns using an ink composition and a printing machine. In general, it can be formed with ink by a known printing method such as gravure printing, offset printing, silk screen printing, transfer printing from a transfer sheet, or the like. As patterns, there are stone patterns imitating the surface of rocks such as wood grain patterns, marble patterns (for example, travertine marble patterns), fabric patterns imitating cloth or cloth patterns, tiled patterns, brickwork patterns, etc. There are also patterns such as marquetry and patchwork that combine these. These patterns are formed not only by multicolor printing with normal yellow, red, blue and black process colors, but also by multicolor printing performed by preparing individual color plates constituting the pattern. .

As the ink composition used for forming the picture layer 4, a binder and a colorant such as a pigment and a dye, an extender pigment, a solvent, a stabilizer, a plasticizer, a catalyst, and a curing agent are appropriately mixed. The binder is not particularly limited, and examples thereof include polyurethane resins, vinyl acetate resins, vinyl chloride / vinyl acetate copolymer resins, vinyl chloride / vinyl acetate / acrylic copolymer resins, chlorinated polyethylene resins, Any one of chlorinated polypropylene resin, acrylic resin, polyester resin, polyamide resin, butyral resin, polystyrene resin, nitrocellulose resin, cellulose acetate resin, etc., alone or 2 A mixture of seeds or more is used. Among these, for the purpose of the present invention, it is possible to use one kind of polyurethane resin, vinyl acetate resin, acrylic resin, polyester resin, cellulose resin, polyamide resin or the like alone or in combination. preferable.
Colorants include carbon black (black), iron black, titanium white, antimony white, yellow lead, titanium yellow, petal, cadmium red, ultramarine, cobalt blue and other inorganic pigments, quinacridone red, isoindolinone yellow, phthalocyanine Organic pigments or dyes such as blue, metallic pigments composed of scaly foil pieces such as aluminum and brass, pearlescent pigments composed of scaly foil pieces such as titanium dioxide-coated mica and basic lead carbonate, and the like are used.
The pattern layer 4 preferably has a thickness of about 1 to 20 μm.

[Film layer 6]
The film layer 6 is a layer laminated on the upper surface of the picture layer 4 via the adhesive layer 5, and is required for the foamed wallpaper of the present invention, stain resistance, cellophane tape resistance, scratch resistance, chemical resistance It is provided for imparting surface characteristics such as property.
Examples of the thermoplastic resin used in the film layer 6 of the present invention include thermoplastic resins such as polyolefin resins such as polyethylene, polypropylene, and polybutene, methacrylic resins, thermoplastic polyester resins, polyvinyl alcohol resins, and fluorine resins. In addition, from the viewpoint of production efficiency, a transparent or translucent commercially available film made of the above resin can be preferably used.

Examples of the commercially available film include fluorine resin films such as polyvinyl fluoride, polyvinylidene fluoride, and ethylene tetrafluoroethylene, olefin resin films coated with urethane or acrylic coating agents, and ethylene-vinyl alcohol copolymer. Examples include a coalesced resin film. Among them, it has excellent performance such as stain resistance, scratch resistance, chemical resistance, etc., shows excellent unevenness followability in embossing, that is, the tensile elongation in the longitudinal direction is sufficiently large, without collapsing by ionizing radiation, An ethylene-vinyl alcohol copolymer resin film having a low production cost and a low smoke concentration during combustion is preferred.
The thickness of the film used for the film layer 6 of the present invention is preferably 10 to 25 μm. If the thickness of the film is within the above range, the unevenness followability of the wallpaper by embossing can be ensured without being restricted in the production of the film.

[Surface protective layer 8]
The surface protective layer 8 is characterized in that the ionizing radiation curable resin composition is crosslinked and cured, and is laminated on the outermost surface of the foamed wallpaper of the present invention, so that the foamed wallpaper has stain resistance, cellophane tape resistance, It improves surface properties such as scratch resistance and chemical resistance. The surface tension of the surface protective layer 8 is preferably 30 dyne / cm or less. If the surface tension of the surface protective layer is within the above range, particularly excellent stain resistance against electric burn can be obtained. The surface tension is a value measured according to JIS K6768.
Here, the ionizing radiation curable resin composition is one having an energy quantum capable of crosslinking and polymerizing molecules in electromagnetic waves or charged particle beams, that is, crosslinking and curing by irradiating with ultraviolet rays or electron beams. It is a composition comprising ionizing radiation curable resin, other components added as necessary, and various additives. In the specification, for example, when the ionizing radiation curable resin in the ionizing radiation curable resin composition is an electron beam curable resin, this is referred to as an electron beam curable resin composition.

[Surface protective layer 8: ionizing radiation curable resin]
As the ionizing radiation curable resin used for the surface protective layer 8, those having a surface tension of preferably 30 dyne / cm or less can be used as appropriate, and are commonly used as ionizing radiation curable resins. The polymerizable monomer, polymerizable oligomer or prepolymer can be appropriately selected and used. Typical examples are described below. “(Meth) acrylate” means “acrylate or methacrylate”.

As the polymerizable monomer, a (meth) acrylate monomer having a radical polymerizable unsaturated group in the molecule is suitable, and among them, a polyfunctional (meth) acrylate is preferred.
The polyfunctional (meth) acrylate is not particularly limited as long as it is a (meth) acrylate having two or more ethylenically unsaturated bonds in the molecule. Specifically, ethylene glycol di (meth) acrylate, propylene glycol di (meth) acrylate, 1,4-butanediol di (meth) acrylate, 1,6-hexanediol di (meth) acrylate, neopentyl glycol di (meth) ) Acrylate, polyethylene glycol di (meth) acrylate, hydroxypivalate neopentyl glycol di (meth) acrylate, dicyclopentanyl di (meth) acrylate, caprolactone modified dicyclopentenyl di (meth) acrylate, ethylene oxide modified diphosphate ( (Meth) acrylate, allylated cyclohexyl di (meth) acrylate, isocyanurate di (meth) acrylate, trimethylolpropane tri (meth) acrylate, ethylene oxide modified trimethylo Propane tri (meth) acrylate, dipentaerythritol tri (meth) acrylate, propionic acid modified dipentaerythritol tri (meth) acrylate, pentaerythritol tri (meth) acrylate, propylene oxide modified trimethylolpropane tri (meth) acrylate, tris ( (Acryloxyethyl) isocyanurate, propionic acid modified dipentaerythritol penta (meth) acrylate, dipentaerythritol hexa (meth) acrylate, ethylene oxide modified dipentaerythritol hexa (meth) acrylate, caprolactone modified dipentaerythritol hexa (meth) acrylate, Examples include ethylene oxide-modified bisphenol A diacrylate. These polyfunctional (meth) acrylates may be used singly or in combination of two or more.

  The ionizing radiation curable resin composition can contain a monofunctional (meth) acrylate together with the above-mentioned polyfunctional (meth) acrylate for the purpose of reducing the viscosity and the like within a range not impairing the effect. Examples of monofunctional (meth) acrylates include methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, butyl (meth) acrylate, pentyl (meth) acrylate, hexyl (meth) acrylate, cyclohexyl ( Examples include meth) acrylate, 2-ethylhexyl (meth) acrylate, lauryl (meth) acrylate, stearyl (meth) acrylate, and isobornyl (meth) acrylate. These monofunctional (meth) acrylates may be used alone or in combination of two or more.

  Next, the polymerizable oligomer is preferably an oligomer having a radically polymerizable unsaturated group in the molecule, particularly an acrylate oligomer having a radically polymerizable unsaturated group, such as an epoxy (meth) acrylate or urethane (meth). Examples include acrylate-based, polyester (meth) acrylate-based, and polyether (meth) acrylate-based oligomers. Here, the epoxy (meth) acrylate oligomer can be obtained, for example, by reacting (meth) acrylic acid with an oxirane ring of a relatively low molecular weight bisphenol type epoxy resin or novolak type epoxy resin and esterifying it. . Further, a carboxyl-modified epoxy (meth) acrylate oligomer obtained by partially modifying this epoxy (meth) acrylate oligomer with a dibasic carboxylic acid anhydride can also be used. The urethane (meth) acrylate oligomer can be obtained, for example, by esterifying, with (meth) acrylic acid, a polyurethane oligomer obtained by a reaction between polyether polyol or polyester polyol and polyisocyanate. Examples of polyester (meth) acrylate oligomers include esterification of hydroxyl groups of polyester oligomers having hydroxyl groups at both ends obtained by condensation of polyvalent carboxylic acids and polyhydric alcohols with (meth) acrylic acid, It can be obtained by esterifying the terminal hydroxyl group of an oligomer obtained by adding an alkylene oxide to a carboxylic acid with (meth) acrylic acid. The polyether (meth) acrylate oligomer can be obtained by esterifying the hydroxyl group of the polyether polyol with (meth) acrylic acid.

  Furthermore, other polymerizable oligomers include polybutadiene (meth) acrylate oligomers with high hydrophobicity that have (meth) acrylate groups in the side chain of polybutadiene oligomers, and silicone (meth) acrylate oligomers that have polysiloxane bonds in the main chain. In a molecule such as an aminoplast resin (meth) acrylate oligomer modified with an aminoplast resin having many reactive groups in a small molecule, or a novolak epoxy resin, bisphenol epoxy resin, aliphatic vinyl ether, aromatic vinyl ether, etc. There are oligomers having a cationic polymerizable functional group.

When an ultraviolet curable resin composition is used as the ionizing radiation curable resin composition, the ultraviolet curable resin composition has a photopolymerization initiator in an amount of 0.1 to 5 with respect to 100 parts by mass of the resin composition. It is preferable to contain about part by mass. The initiator for photopolymerization can be appropriately selected from those conventionally used and is not particularly limited. For example, for a polymerizable monomer or polymerizable oligomer having a radically polymerizable unsaturated group in the molecule. Benzoin, benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether, benzoin-n-butyl ether, benzoin isobutyl ether, acetophenone, dimethylaminoacetophenone, 2,2-dimethoxy-2-phenylacetophenone, 2,2-diethoxy-2 -Phenylacetophenone, 2-hydroxy-2-methyl-1-phenylpropan-1-one, 1-hydroxycyclohexyl phenyl ketone, 2-methyl-1- [4- (methylthio) phenyl] -2-morpholino-propane-1 - 4- (2-hydroxyethoxy) phenyl-2 (hydroxy-2-propyl) ketone, benzophenone, p-phenylbenzophenone, 4,4′-diethylaminobenzophenone, dichlorobenzophenone, 2-methylanthraquinone, 2-ethylanthraquinone, 2 -Tertiary butylanthraquinone, 2-aminoanthraquinone, 2-methylthioxanthone, 2-ethylthioxanthone, 2-chlorothioxanthone, 2,4-dimethylthioxanthone, 2,4-diethylthioxanthone, benzyl dimethyl ketal, acetophenone dimethyl ketal, etc. It is done.
Examples of the polymerizable oligomer having a cationic polymerizable functional group in the molecule include aromatic sulfonium salts, aromatic diazonium salts, aromatic iodonium salts, metallocene compounds, and benzoin sulfonic acid esters.
Moreover, as a photosensitizer, p-dimethylbenzoic acid ester, tertiary amines, a thiol type sensitizer, etc. can be used, for example.
In the present invention, it is preferable to use an electron beam curable resin composition as the ionizing radiation curable resin composition. This is because the electron beam curable resin composition can be made solvent-free, is more preferable from the viewpoint of environment and health, and does not require a photopolymerization initiator, and can provide stable curing characteristics.

[Surface protective layer 8: silicone (meth) acrylate]
The ionizing radiation curable resin composition used for the surface protective layer 8 preferably contains silicone (meth) acrylate. Silicone (meth) acrylate is added mainly for the purpose of controlling the surface tension of the surface protective layer at the same time as providing surface properties such as stain resistance to wallpaper due to a synergistic effect with the ionizing radiation curable resin. is there. Silicone (meth) acrylate is one of modified silicone oils in which (meth) acrylic groups are introduced into one or both ends of a silicone oil composed of polysiloxane. Conventionally known silicone (meth) acrylates can be used, and are not particularly limited as long as the organic group is a (meth) acrylic group, and a modified silicone oil having 1 to 6 organic groups can be preferably used. . The structure of the modified silicone oil is roughly divided into a side chain type, a both-end type, a single-end type, and a side-chain both-end type depending on the bonding position of the organic group to be substituted. There is no particular limitation.
The content of the silicone (meth) acrylate may be appropriately adjusted so that the surface tension of the surface protective layer is in a desired range. However, from the viewpoint of sufficiently improving the contamination resistance and the effect of using the ionizing radiation. 0.5-4 mass parts is preferable with respect to 100 mass parts of curable resin, more than 1.0-2.5 mass parts is more preferable, and 1.5-2.5 mass parts is further more preferable. Moreover, as a functional group equivalent (molecular weight / functional group number) of silicone (meth) acrylate, what has the conditions of 100-20000, for example, Preferably it is 100-10000 is mentioned.

[Surface protective layer 8: Various additives]
The ionizing radiation curable resin composition can contain various additives depending on the desired physical properties of the resulting surface protective layer. Examples of the additive include a weather resistance improver, an abrasion resistance improver, a polymerization inhibitor, a crosslinking agent, an infrared absorber, an antistatic agent, an adhesion improver, a leveling agent, a thixotropic agent, and a coupling agent. , Plasticizers, antifoaming agents, fillers, solvents, colorants and the like.
Here, as the weather resistance improving agent, an ultraviolet absorber or a light stabilizer can be used. The ultraviolet absorber may be either inorganic or organic. As the inorganic ultraviolet absorber, titanium dioxide, cerium oxide, zinc oxide or the like having an average particle size of about 5 to 120 nm can be preferably used. Moreover, as an organic type ultraviolet absorber, benzotriazole type, for example, 2- (2-hydroxy-5-methylphenyl) benzotriazole, 2- (2-hydroxy-3,5-di-tert-) is specifically mentioned. Amylphenyl) benzotriazole, 3- [3- (benzotriazol-2-yl) -5-tert-butyl-4-hydroxyphenyl] propionic acid ester of polyethylene glycol, and the like. On the other hand, examples of the light stabilizer include hindered amines, specifically 2- (3,5-di-tert-butyl-4-hydroxybenzyl) -2′-n-butylmalonate bis (1,2,2). , 6,6-pentamethyl-4-piperidyl), bis (1,2,2,6,6-pentamethyl-4-piperidyl) sebacate, tetrakis (2,2,6,6-tetramethyl-4-piperidyl)- 1,2,3,4-butanetetracarboxylate and the like. In addition, as the ultraviolet absorber or light stabilizer, a reactive ultraviolet absorber or light stabilizer having a polymerizable group such as a (meth) acryloyl group in the molecule can be used.

Examples of the wear resistance improver include, for inorganic substances, spherical particles such as α-alumina, silica, kaolinite, iron oxide, diamond, and silicon carbide. Examples of the particle shape include a sphere, an ellipsoid, a polyhedron, a scale shape, and the like. Although there is no particular limitation, a spherical shape is preferable. Organic materials include synthetic resin beads such as cross-linked acrylic resin and polycarbonate resin. The particle size is usually about 10 to 200% of the film thickness. Among these, spherical α-alumina is particularly preferable because it has high hardness and a large effect on improving wear resistance, and it is relatively easy to obtain spherical particles.
Examples of the polymerization inhibitor include hydroquinone, p-benzoquinone, hydroquinone monomethyl ether, pyrogallol, t-butylcatechol and the like, and examples of the crosslinking agent include a polyisocyanate compound, an epoxy compound, a metal chelate compound, an aziridine compound, and an oxazoline compound. Used.
As the filler, for example, barium sulfate, talc, clay, calcium carbonate, aluminum hydroxide and the like are used.
Examples of the colorant include known coloring pigments such as quinacridone red, isoindolinone yellow, phthalocyanine blue, phthalocyanine green, titanium oxide, and carbon black.
As the infrared absorber, for example, a dithiol metal complex, a phthalocyanine compound, a diimmonium compound, or the like is used.

[Surface Protective Layer 8: Formation of Surface Protective Layer]
In the formation of the surface protective layer 8, first, an ionizing radiation curable resin such as a polymerizable monomer or a polymerizable oligomer, silicone (meth) acrylate added as necessary, and various additives are homogeneous at predetermined ratios. An ionizing radiation curable resin composition obtained by mixing with the above is prepared. The viscosity of the ionizing radiation curable resin composition is not particularly limited as long as it is a viscosity capable of forming an uncured resin layer on the surface of the base material by a coating method described later. It may be added.
Solvents include toluene, xylene, ethyl acetate, butyl acetate, methyl ethyl ketone, methyl isobutyl ketone, water-insoluble organic solvents such as ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, methanol, ethanol, isopropyl alcohol, and normal propyl alcohol. Examples thereof include water-soluble organic solvents, water, and mixed solvents thereof. The amount of the solvent in the ionizing radiation curable resin composition may be appropriately selected according to the viscosity of the ionizing radiation curable resin composition, but the ionizing radiation curable resin composition is usually 65 to 85 mass on a solid basis. %.

  The ionizing radiation curable resin composition thus prepared has a gravure coat, a bar coat, a roll coat, a reverse roll coat, a comma so that the thickness after curing is 1 to 20 μm. It coats by well-known systems, such as a coat, preferably a gravure coat, and forms an uncured resin layer. A surface protective layer having desired performance is obtained when the thickness after curing is 1 μm or more. The thickness of the surface protective layer after curing is preferably 2 to 20 μm from the viewpoint of sufficiently obtaining the effect of providing the surface protective layer.

The uncured resin layer formed in this way is cured by irradiating with ionizing radiation such as an electron beam or ultraviolet rays to form a surface protective layer. Here, when an electron beam is used as the ionizing radiation, the acceleration voltage can be appropriately selected according to the resin used and the thickness of the layer, but the uncured resin layer is usually cured at an acceleration voltage of about 70 to 300 kV. preferable.
In electron beam irradiation, the transmission capability increases as the acceleration voltage increases. Therefore, when using a substrate that deteriorates due to the electron beam as the substrate, the transmission depth of the electron beam and the thickness of the resin layer are substantially equal. By selecting the accelerating voltage so as to be equal to each other, it is possible to suppress the irradiation of the electron beam to the base material, and to minimize the deterioration of the base material due to the excessive electron beam.

The irradiation dose is preferably such that the crosslinking density of the ionizing radiation curable resin is saturated, and is usually selected in the range of 5 to 300 kGy (0.5 to 30 Mrad), preferably 10 to 50 kGy (1 to 5 Mrad).
Further, the electron beam source is not particularly limited. For example, various electron beam accelerators such as a cockroft Walton type, a bandegraft type, a resonant transformer type, an insulated core transformer type, a linear type, a dynamitron type, a high frequency type, etc. Can be used.
When ultraviolet rays are used as the ionizing radiation, those containing ultraviolet rays having a wavelength of 190 to 380 nm are emitted. There is no restriction | limiting in particular as an ultraviolet-ray source, For example, a high pressure mercury lamp, a low pressure mercury lamp, a metal halide lamp, a carbon arc lamp etc. are used.

  The surface protective layer thus formed has various functions by adding various additives, for example, a so-called hard coat function, anti-fogging coat function, and anti-fouling coat having high hardness and scratch resistance. A function, an antiglare coating function, an antireflection coating function, an ultraviolet shielding coating function, an infrared shielding coating function, and the like can also be imparted.

[Adhesive layer 5]
When the adhesiveness between the film layer 6 and the non-foamed resin layer 31 is low, for example, when an ethylene-vinyl alcohol copolymer resin film is used for the film layer 6, the adhesive layer 5 is provided between the two layers as necessary. It is preferable to provide it. Although there is no restriction | limiting in particular as an adhesive agent used for the adhesive bond layer 5, A heat sensitive adhesive is preferable from the manufacturing process of this invention. A heat-sensitive adhesive is generally an adhesive that is a solid at normal temperature, melts or softens when heated, expresses adhesiveness, and solidifies and solidifies when cooled, with a thermoplastic resin as the main component. Say. This is dissolved in an appropriate solvent or melted by heating, applied to one or both adhesive surfaces of the adherend, and the two are overlapped and heated and pressed to bond them. Specific examples of the thermoplastic resin include (meth) acrylic resin, polyurethane resin, polyester, polyamide resin, (meth) acrylic acid ester-olefin copolymer resin, vinyl acetate resin, ethylene-acetic acid. Thermoplastic which is the main component of easy-adhesive resins and copolymers, such as vinyl copolymer resins, ionomer resins, olefin-α olefin copolymer resins, or mixed resins thereof, and olefin resins and foamed resin compositions A blended product of a resin and a thermoplastic resin as a main component of the film layer can be mentioned.

The adhesive layer 5 is provided between the non-foamed resin layer 31 and the film layer 6 as described above and as shown in FIG. 1 for the purpose of improving the interlayer adhesive force. It can also be provided between the foamed resin layer 32. In addition to providing an adhesive layer, a physical or chemical surface treatment such as an oxidation method or a concavo-convex method can be applied to one or both sides as desired in order to improve interlayer adhesion.
Examples of the oxidation method include corona discharge treatment, chromium oxidation treatment, flame treatment, hot air treatment, ozone / ultraviolet treatment method, and examples of the unevenness method include a sand blast method and a solvent treatment method. These surface treatments are appropriately selected depending on the type of substrate, but generally, a corona discharge treatment method is preferably used from the viewpoints of effects and operability.

[Primer layer 7]
The foamed wallpaper of the present invention is provided with a primer layer 7 between these layers as needed for the purpose of improving the adhesion between the ionizing radiation curable resin composition used for the surface protective layer 8 and the film layer 6. Can be provided. The resin preferably used in the primer layer 7 is, for example, excellent in adhesion between the resin used in the film layer 6 and an ionizing radiation curable resin composition such as acrylic resin, polyurethane resin, and urethane-acrylic resin. Can be used. Moreover, a primer layer can also be provided between the foamed resin layer 32 and the non-foamed resin layer 31 and between the non-foamed resin layer 31 and the film layer 6 for the purpose of reinforcing the interlayer adhesion.

[Uneven pattern 10]
The foamed wallpaper of the present invention is preferably provided with a concavo-convex pattern 10 by embossing in order to impart excellent design properties. The concavo-convex pattern 10 is formed by heating and pressing with an embossing plate from the upper surface of the surface protective layer 8, that is, the outermost layer side, when the wallpaper in the manufacturing process is at a temperature that can be embossed by any means. Can do. For the formation of the concavo-convex pattern 10, a well-known sheet or rotary embossing machine is used. The shape of the concavo-convex pattern 10 includes a wood grain conduit groove, a stone plate surface unevenness, a cloth surface texture, a satin texture, a grain texture, a hairline. , There are many strips.

[Production method]
The foamed wallpaper of the present invention is manufactured, for example, by the following manufacturing method, but is not limited thereto.
The foam wallpaper shown in FIGS. 1 and 2 is manufactured as follows. A resin constituting the primer layer 7 and an ionizing radiation curable resin composition are sequentially applied to one surface of the film layer 6 made of a thermoplastic resin film, and an adhesive and a primer layer are applied to the other surface as necessary. A constituent resin is applied, and a predetermined ionizing radiation is further applied to crosslink and cure the ionizing radiation curable resin composition to obtain a surface protective sheet. Moreover, the foamed resin composition which consists of the thermoplastic resin which contains the non-foamed resin composition containing the resin which comprises a non-foamed resin layer on the base material 2, and a foaming agent, an inorganic filler, and other additives as needed. A non-foamed resin layer and a foamed resin layer obtained by forming a product together with a T-die by an extrusion film-forming method are laminated (if necessary, a non-foamed resin layer, a foamed resin layer, a non-foamed resin layer After the ink composition constituting the pattern layer 4 is applied by gravure printing, the non-foamed resin layer and the foamed resin layer are crosslinked and cured by irradiation with an electron beam, and a heating foaming furnace is further formed. The foamed resin composition is foamed at about 250 ° C. to form the foamed resin layer 32 to obtain a base sheet. Next, after the substrate sheet is cooled, it is reheated to about 150 ° C. and then between the cooling roll (surface protective sheet side) and the pressure roll on which the embossed plate is formed from the outermost layer side of the surface protective layer sheet. Both the sheets are thermocompression-bonded by passing through, and after forming the concavo-convex pattern 10, the foam of the present invention in which the concavo-convex pattern 10 is formed from the outermost layer side of the surface protective layer 8 to the non-foamed resin layer 31 by cooling. You can get a wallpaper. In addition, as above-mentioned, a primer layer and an adhesive bond layer can further be provided between desired layers.

EXAMPLES Next, although an Example demonstrates this invention further in detail, this invention is not limited at all by this example.
(Evaluation methods)
The decorative sheet obtained in each example was evaluated by the following methods.
(1) Evaluation of contamination resistance (pollutants)
In accordance with JIS K-6902, water-based pen (black), water-based pen (red), red crayon, lipstick, whiteboard marker and oily magic are attached to the foamed wallpaper as a pollutant. The gauze was wiped dry, and the remaining state of the pollutants was visually evaluated. Judgment criteria were evaluated as follows.
○ Contaminant can be completely wiped out △ Contaminant remains slightly, but it is minor and has no practical problem × Contaminant remains remarkably (2) Evaluation of contamination resistance (electric burn)
Electric dust was reproduced by attaching carbon black on the surface of the foamed wallpaper obtained in Examples and Comparative Examples. This was wiped off with a sponge containing a neutral detergent, and the wiping property of the electric burn was evaluated visually.
○ There was no carbon black spray residue △ Carbon black spray residue remained slightly, but there was no problem in practical use. × Carbon black spray residue was remarkable (3) Scratch resistance Surface-enhanced product performance by the Japan Vinyl Industry The scratch resistance was evaluated according to the method described in the display (implemented on January 1, 1997).
A test piece of 25 pieces (25 mm × 250 mm) is taken from a standard location from the inside 10 cm from each end of the wallpaper obtained in each example. The collected test piece is left for 24 hours or more under the conditions of a temperature of 15 to 30 ° C. and a relative humidity of 65 ± 20%, and using a friction tester II (load 200 g) defined in JIS L 0823, the transition distance is 120 mm. The gap was moved 5 times with 30 reciprocations per minute, and the degree of damage was visually evaluated according to the following evaluation criteria.
○ Grade 5 (no change)
△ Grade 4 (Slight changes on the surface)
× 3rd grade (The surface is broken and the vinyl layer is visible)
(4) Evaluation of uneven pattern (embossing moldability)
The uneven pattern of the foamed wallpaper obtained in the examples and comparative examples was evaluated visually. Judgment criteria were evaluated as follows.
○ Uneven pattern is sharp and has excellent design properties. △ Uneven pattern is not found in the uneven pattern, but there is no problem. × Unevenness in uneven pattern is significant. (5) Evaluation of occurrence of cracks Obtained in Examples and Comparative Examples Evaluation of the occurrence of cracks in the obtained wallpaper was performed using an electron microscope. Judgment criteria were evaluated as follows.
○ Cracks do not occur △ Cracks can be seen, but there are no practical problems. × Cracks remarkably occur (6) Evaluation of workability (curlability)
The foamed wallpaper produced in each of the examples and comparative examples was used for wallpaper wallpaper paste (manufactured by Yayoi Chemical Industry Co., Ltd., trade name: Rua Mild) using a wallpaper paste coating machine at a coating amount of 130 g / m ² . After coating, the curling property (floating property) of the wallpaper edge after 1 hour under the condition of 20 ° C. (relative humidity: 65%) was evaluated according to the following criteria.
○ Floating width 5mm or less × Floating width 5mm or more (7) Evaluation of workability (opening)
The wallpaper produced in each of the examples and comparative examples was applied to a wallpaper construction paste (manufactured by Yayoi Chemical Industry Co., Ltd., trade name “Lure Mild”) at a coating amount of 130 g / m ² using a wallpaper coating machine. After coating, the wallpaper was cut in half in the width direction and pasted on a semi-incombustible gypsum board with a thickness of 9 mm so that the ears overlapped. After construction and leaving at 20 ° C. (relative humidity: 65%) for 1 week, the width of the opening of the part where the ears overlap (joint part) is measured using a microscope. Evaluated by criteria.
○: Opening width less than 0.08 mm ×: Opening width 0.08 mm or more (8) Evaluation of workability (peelability)
The wallpaper produced in each of the examples and comparative examples was applied to a wallpaper construction paste (manufactured by Yayoi Chemical Industry Co., Ltd., trade name “Loa Mild”) using a wallpaper paste coating machine at a coating amount of 120 g / m ² . It applied and affixed on the gypsum board (Yoshino gypsum Co., Ltd. make, brand name: non-combustible tiger board, size: 1800 mm x 900 mm, thickness: 12.5 mm). Under an environment of 20 ° C. (relative humidity: 30%), it was left for one week, and the wallpaper was gently peeled off from the upper corner. At this time, the peelability was evaluated based on whether or not the wallpaper was peeled between the backing materials, and when the wallpaper was peeled between the backing materials, how many times the wallpaper was peeled off.
(9) Evaluation of workability (folding property)
Using a gluing machine (manufactured by Yayoi Chemical Industry Co., Ltd.) on the back surface of the wallpaper 20 m ² produced in each of the examples and comparative examples, a commercially available adhesive for wallpaper (Yaoi Chemical Co., Ltd. ]) Was applied at 120 g / m ^2, and the adhesive surfaces were bonded together and folded. A load of 15 kg was applied to the folded part and left for 15 minutes. Next, the wallpaper was applied to a gypsum board (Yoshino Gypsum Co., Ltd. “Non-combustible Tiger Board” thickness 12.5 mm) and visually evaluated.
(10) Evaluation of dam leakage In each of the examples and comparative examples, the state of dam leakage of the foamed resin composition when the foamed resin composition is coated on the base material by a comma coater method is visually confirmed. Evaluation based on the criteria.
○: The foamed resin composition did not leak at all ×: The foamed resin composition leaked the weir (11) Evaluation of production safety (generation of static electricity)
In each Example and Comparative Example, after applying the foamed resin composition, after winding with a roll, when unwinding when printing the pattern layer, static electricity generation state (spark generation state) ) Was visually confirmed and evaluated according to the following criteria.
○: No static electricity was generated. ×: Static electricity was generated and it was in a dangerous state.

Example 1
As the base material 2, a backing paper for wallpaper having a weight of rice of 60 g / m ² (manufactured by Kojin Co., Ltd., WK-FKKD) is used. A non-foamed resin composition and a foamed resin composition having the following composition are simultaneously formed using an extruder with a T-die, and a non-foamed resin layer and a foamed resin layer are formed to have a thickness of 10 μm and 100 μm, respectively. A base material was laminated on the surface of the non-foamed resin layer. Extrusion conditions at this time were a cylinder temperature of 160 ° C. for the non-foamed resin layer, a cylinder temperature of 120 ° C. for the foamed resin layer, and a die temperature of 120 ° C. for both. A pattern layer 4 was formed by gravure printing with an application amount of 3 g / m ² using an ink containing an acrylic resin as a binder and carbon black and a stem as a colorant. Next, the foamed resin layer was irradiated with an electron beam having a pressurization voltage of 175 kV and an irradiation dose of 50 kGy (5 Mrad) to perform a crosslinking treatment.
Separately from the above, an ethylene-vinyl alcohol copolymer resin (manufactured by Kuraray Co., Ltd., Eval Film HF-ME (thickness: 12 μm), ethylene content 44 mol%) coated with an adhesive in advance as the film layer 6 is used. The primer layer 7 is formed by gravure printing a urethane-acrylic copolymer resin at a coating amount of 2.0 g / m ² on the upper surface (side where the adhesive is not applied) of the film layer 6, An ionizing radiation curable resin having the following composition was coated on the surface by a gravure offset coater method at a coating amount of 2.0 g / m ² . After coating, the surface protective layer 8 was formed by irradiating an electron beam with a pressurization voltage of 125 kV and an irradiation dose of 30 kGy (3 Mrad) to cure the ionizing radiation curable resin, thereby obtaining a surface protective sheet.
The foamed resin layer 32 is formed by foaming the foamed resin composition at 230 ° C. using a heating foaming furnace on the base material obtained by applying the pattern layer 4 and laminating the non-foamed resin composition and the foamed resin composition. After obtaining the base material, the surface protection sheet obtained above and the embossing mold are passed between the cooling roll and the pressure roll, and the surface is uneven by embossing and thermocompression bonding. A wallpaper with a pattern was obtained.

Non-foamed resin composition composition Ethylene-vinyl acetate copolymer (manufactured by Sumitomo Chemical Co., Ltd., trade name: Smitate CV5053): 100 parts by weight Foamed resin composition composition Ethylene-vinyl acetate copolymer (manufactured by Sumitomo Chemical Co., Ltd.) , Trade name: Smitate CV5053): 100 parts by weight Foaming agent (manufactured by Eiwa Kasei, trade name: ADCA # 3): 4 parts by weight Calcium carbonate (Shiraishi Kogyo, trade name: Whiten H): 30 parts by weight Titanium dioxide ( Pigment) (manufactured by DuPont, trade name: Taipure R-108): 20 parts by weight Light stabilizer (trade name: OF-101): 1 part by weight Crosslinker (manufactured by JSR Corporation, trade name: Obstar JVA-702) ): 1 part by mass Ionizing radiation curable resin composition Hexafunctional urethane acrylate: 60 parts by mass Trifunctional urethane acrylate: 40 parts by mass Silica (particle size: about 3 μm): 0 parts by weight of hexafunctional silicone methacrylate: 2 parts by weight

Examples 2-7
A wallpaper was obtained in the same manner as in Example 1 except that the substrate 2 was changed to the one shown in Table 1.

Example 8
As the base material 2, a backing paper for wallpaper having a weight of rice of 60 g / m ² (WK-FKKD, manufactured by Kojin Co., Ltd.) is used. The non-foamed resin composition and the foamed resin composition used in Example 1 were simultaneously formed using a T-die extruder, and the non-foamed resin layer and the foamed resin were respectively formed to have a thickness of 15 μm, 100 μm, and 10 μm. A layer and a non-foamed resin layer were formed in this order, and a substrate was laminated on the surface of the non-foamed resin layer having a thickness of 10 μm. Extrusion conditions at this time were as follows: the non-foamed resin layer (thickness 15 μm) had a cylinder temperature of 160 ° C., the foamed resin layer had a cylinder temperature of 120 ° C., and the non-foamed resin layer (thickness 10 μm) had a cylinder temperature of 100 ° C. The temperatures were all 120 ° C.
Separately from the above, an ethylene-vinyl alcohol copolymer resin (manufactured by Kuraray Co., Ltd., Eval Film HF-ME (thickness: 12 μm), ethylene content 44 mol%) coated with an adhesive in advance as the film layer 6 is used. The primer layer 7 is formed by gravure printing a urethane-acrylic copolymer resin at a coating amount of 2.0 g / m ² on the upper surface (side where the adhesive is not applied) of the film layer 6, An ionizing radiation curable resin having the following composition was coated on the surface by a gravure offset coater method at a coating amount of 2.0 g / m ² . After coating, the surface protective layer 8 was formed by irradiating an electron beam with a pressurization voltage of 125 kV and an irradiation dose of 30 kGy (3 Mrad) to cure the ionizing radiation curable resin, thereby obtaining a surface protective sheet.
A substrate obtained by applying the pattern layer 4 and laminating a non-foamed resin composition (10 μm), a foamed resin composition (100 μm), and a non-foamed resin layer (15 μm) in this order at 230 ° C. using a heating foaming furnace. After obtaining the base material on which the foamed resin composition is formed by foaming the foamed resin composition, it is passed between the cooling roll and the pressure roll on which the embossing mold is formed simultaneously with the surface protective sheet obtained above, A wallpaper having a concavo-convex pattern on the surface was obtained by thermocompression bonding while embossing.

Example 9
A wallpaper was obtained in the same manner as in Example 8 except that the substrate 2 was changed to the one described in Table 1.

Comparative Example 1
A wallpaper was obtained in the same manner as in Example 1 except that the resin composition constituting the surface protective layer and the ionizing radiation curable resin composition were changed to those shown in Table 1.
Here, an acrylic resin (manufactured by Matsui Dye Chemical Co., Ltd., trade name: Mica Primer EC-CRWD) was used as the acrylic water-based ink.

Comparative Example 2
As the base material 2, a backing paper for paper having a weight of 60 g / m ² (manufactured by Kojin Co., Ltd., WK-FKKD) was used, and the non-foamed resin composition and the foamed resin composition used in Example 1 were A film was simultaneously formed using a die extruder, a non-foamed resin layer and a foamed resin layer were formed so as to have thicknesses of 10 μm and 100 μm, respectively, and a substrate was laminated on the surface of the non-foamed resin layer. The extrusion conditions at this time were as follows: the non-foamed resin layer had a cylinder temperature of 160 ° C, the foamed resin layer had a cylinder temperature of 120 ° C, and the die temperature was 120 ° C.
On top of that, a pattern layer 4 is formed by gravure printing with an application amount of 2.0 g / m ² using an ink containing an acrylic resin as a binder and carbon black and a petrol as a colorant. The ionizing radiation curable resin composition having the composition of Example 1 was applied by a gravure offset coater method at a coating amount of 2.0 g / m ² . After coating, the surface protective layer 8 was formed by irradiating an electron beam with a pressurization voltage of 125 kV and an irradiation dose of 30 kGy (3 Mrad) to cure the ionizing radiation curable resin. The printed sheet obtained above is foamed with a foamed resin composition at 230 ° C. using a heating foaming furnace to form the foamed resin layer 3, and then between the cooling roll and the pressure roll on which the embossing mold is formed. The wallpaper which gave the surface the uneven pattern by embossing was obtained.

Comparative Example 3
In Comparative Example 2, a wallpaper was obtained in the same manner as in Comparative Example 2 except that the film layer 6 and the surface protective layer 8 were not formed.

Table 1 shows the results of the above evaluations on the wallpapers obtained in Examples 1-9 and Comparative Examples 1-3.
The wallpaper obtained in Examples 1 to 9 showed high performance in all evaluation points. On the other hand, the wallpaper obtained in Comparative Example 1 in which the ionizing radiation curable resin composition is not used for the surface protective layer is excellent in evaluation of embossability, crack generation, scratch resistance, and production stability. Other surface physical properties are insufficient and there is no film layer, but Comparative Example 2 in which the surface protective layer uses an ionizing radiation curable resin composition has insufficient evaluation of crack generation and scratch resistance. In Comparative Example 3 having no film layer and no surface protective layer, evaluation of stain resistance, scratch resistance, and generation of cracks was insufficient.

* 1) Substrate A (backing paper): backing paper for wall paper with a weight of rice of 60 g / m ² (manufactured by Kojin Co., Ltd., WK-FKKD)
* 2) Substrate B (single glossy backing paper): single glossy backing paper (thickness: 100 μm) with 60 g / m ² of rice weighed with a Yankee dryer
* 3) Substrate C (lining material-1): backing material made of paper by adjusting the weight of rice to 60 g / m ² and adjusting the interlayer strength to the values shown in Table 1. * 4) Substrate D (lining material-2) : A backing material made of paper with a weight of rice of 60 g / m ² and a thickness of 90 μm, and the Clark stiffness adjusted to the values shown in Table 1.

  According to the present invention, there is provided a vinyl chloride resin that is excellent in uneven followability by embossing, and is excellent in contaminants such as water-based pens and oil-based pens, stain resistance against electric burns, etc., and in workability and production safety. Unused foam wallpaper can be obtained.

It is a schematic diagram which shows the cross section of the foam wallpaper of this invention. It is a schematic diagram which shows the cross section of the foam wallpaper of this invention.

Explanation of symbols

1. Foam wallpaper Base material 3. Resin layer 31. Non-foamed resin layer 31A. Non-foamed resin layer 31B. Non-foamed resin layer 32. Foamed resin layer 4. Pattern layer 5. Adhesive layer 6. 6. Film layer Primer layer 8. Surface protective layer 10. Uneven pattern

Claims (13)

  A wallpaper in which at least a resin layer, a film layer, and a surface protective layer are sequentially laminated on a substrate, the resin layer comprising a foamed resin layer and a non-foamed resin layer, and the surface protective layer is an ionizing radiation curable resin A foam wallpaper obtained by crosslinking and curing the composition.   The foamed wallpaper according to claim 1, wherein the resin layer is laminated in order of the non-foamed resin layer and the foamed resin layer from the base material side.   The foamed wallpaper according to claim 1, wherein the resin layer is laminated in the order of a non-foamed resin layer, a foamed resin layer, and a non-foamed resin layer from the substrate side.   The foamed wallpaper according to any one of claims 1 to 3, wherein the surface protective layer has a surface tension of 30 dyne / cm or less.   The foamed wallpaper according to any one of claims 1 to 4, wherein the ionizing radiation curable resin composition contains silicone (meth) acrylate.   The resin which comprises a foamed resin layer contains at least 1 sort (s) of ethylene-vinyl acetate type | system | group copolymer (EVA) and ethylene-methyl methacrylate copolymer (EMMA) in any one of Claims 1-5. Foam wallpaper.   The foamed wallpaper according to any one of claims 1 to 6, wherein the resin constituting the non-foamed resin layer is a polyolefin resin.   The foamed wallpaper according to claim 7, wherein the polyolefin-based resin contains at least one of an ethylene-vinyl acetate copolymer (EVA) and an ethylene-methyl methacrylate copolymer (EMMA).   The foamed wallpaper according to any one of claims 1 to 8, wherein the substrate is a glossy backing paper having a surface smoothness measured in accordance with JIS P8119 of 40 seconds or less.   The foamed wallpaper according to claim 9, wherein the one-sided backing paper has an underwater elongation of 1.2% or less.   The foamed wallpaper according to any one of claims 1 to 8, wherein the base material is a backing material having an interlayer strength of 12 to 40 N / m.   The foamed wallpaper according to any one of claims 1 to 8, wherein the base material is a backing material having a Clark stiffness of 75% or less.   The foamed wallpaper according to any one of claims 1 to 12, which is mechanically embossed from the surface protective layer side.

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