JP2009235635A - Foamed wall paper - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a foamed wall paper having practical surface strength, suppressed in generation of curl and crack and excellent in versatility. <P>SOLUTION: Provided is a foamed wall paper having at least a foamed resin layer on a substrate, wherein (1) the foamed resin layer is formed by foaming a foaming agent-containing resin layer, (2) the foaming agent-containing resin layer contains as the resin components, low-density polyethylene of 0.92-0.95 g/cm<SP>3</SP>density and very low density polyethylene of 0.85-0.91 g/cm<SP>3</SP>density, which very low density polyethylene is a mixture of (i) very low density polyethylene A having 1-4C side chains and (ii) very low density polyethylene B having ≥6C side chains, and (3) the contents of the very low density polyethylene A and the very low density polyethylene B in the resin components are each ≥10 wt.%. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a highly versatile foamed wallpaper having practical surface strength and curling (bending wrinkles) and cracks (cracks) being suppressed.

  Foamed wallpaper generally has a foamed resin layer on a substrate. This foamed resin layer is the thickest layer in the foam wallpaper, and tends to affect the characteristics and cost of the foam wallpaper. Therefore, the characteristics of the foamed wallpaper can be changed by changing the type of resin in the foamed resin layer.

There is an attempt to reduce the cost while improving the surface strength by making the resin contained in the foamed resin layer low density polyethylene having a density of 0.92 to 0.95 g / cm ³ . However, when the resin component is composed of only low-density polyethylene, there is a problem that the foamed wallpaper is easily curled and cracks are easily generated during bending.

In order to improve the above problem, for example, it is conceivable to include ultra-low density polyethylene having a density of 0.85 to 0.91 g / cm ³ . For example, Patent Document 1 discloses a resin composition for wallpaper in which ultra-low density polyethylene (ethylene / α-olefin random copolymer) is contained in a resin component in an amount of 50 to 95% by weight, and for wallpaper produced using the resin composition. The original fabric is described.

  By using the wallpaper resin composition described in Patent Document 1, the occurrence of curling and cracking can be effectively suppressed. However, since ultra-low density polyethylene is expensive, the production cost of foamed wallpaper is high and lacks versatility.

Therefore, it is desired to develop a highly versatile foam wallpaper having a practical surface strength and curling and cracking suppressed.
JP 2005-120487 A

  An object of the present invention is to provide a highly versatile foamed wallpaper having practical surface strength and curling and cracking suppressed.

  As a result of intensive studies, the inventor has found that the above object can be achieved when a low-density polyethylene and a specific ultra-low-density polyethylene are used in combination as a resin component contained in the foamed resin layer. It came to complete.

That is, the present invention relates to the following foamed wallpaper.
1. A foam wallpaper having at least a foam resin layer on a substrate,
(1) The foamed resin layer is formed by foaming a foaming agent-containing resin layer,
(2) the blowing agent-containing resin layer, as a resin component, containing a low-density polyethylene and very low density polyethylene having a density of 0.85~0.91g / cm ³ of density 0.92~0.95g / cm ³ The ultra low density polyethylene is a mixture of i) ultra low density polyethylene A having 1 to 4 carbon side chains and ii) ultra low density polyethylene B having 6 or more side chains,
(3) The contents of the ultra-low density polyethylene A and the ultra-low density polyethylene B in the resin component are each 10% by weight or more.
Foam wallpaper characterized by that.
2. Item 2. The foamed wallpaper according to Item 1, wherein the content of the ultra-low density polyethylene A and the ultra-low density polyethylene B in the resin component is 10% by weight or more and 25% by weight or less, respectively.
3. Item 3. The foamed wallpaper according to Item 1 or 2, wherein a non-foamed resin layer A is further formed on the front surface of the foamed resin layer.
4). Item 4. The foamed wallpaper according to any one of Items 1 to 3, wherein a non-foamed resin layer B is further formed between the base material and the foamed resin layer.
5. Item 5. The foamed wallpaper according to Item 3 or 4, wherein the non-foamed resin layer A contains an ethylene-methacrylic acid copolymer having a methacrylic acid content of 15% by weight or less as a resin component.
6). Item 6. The foamed wallpaper according to any one of Items 1 to 5, wherein embossing is performed on the outermost surface layer.

Hereinafter, the foamed wallpaper of the present invention will be described in detail.

The foamed wallpaper of the present invention has at least a foamed resin layer on the substrate,
(1) The foamed resin layer is formed by foaming a foaming agent-containing resin layer,
(2) the blowing agent-containing resin layer, as a resin component, containing a low-density polyethylene and very low density polyethylene having a density of 0.85~0.91g / cm ³ of density 0.92~0.95g / cm ³ The ultra low density polyethylene is a mixture of i) ultra low density polyethylene A having 1 to 4 carbon side chains and ii) ultra low density polyethylene B having 6 or more side chains,
(3) Content of the said ultra-low density polyethylene A and the said ultra-low density polyethylene B in the said resin component is 10 weight% or more, respectively, It is characterized by the above-mentioned.

  The foamed wallpaper of the present invention having the above characteristics contains low-density polyethylene and ultra-low-density polyethylene as the resin component contained in the foam-containing resin layer, and particularly ultra-low-density polyethylene and ultra-low-density polyethylene A and ultra-low-density polyethylene. Since each of the low density polyethylene B contains 10% by weight or more, curling and cracking of the foam wallpaper is suppressed. In addition, since practical surface strength is ensured and the content of ultra-low density polyethylene is set as low as possible by 10% by weight or more, the production cost can be suppressed, so that general-purpose foaming is possible. Become wallpaper.

  Hereinafter, each requirement will be described separately.

The base material is not particularly limited as long as it has mechanical strength, heat resistance and the like suitable as a base material for foamed wallpaper. For example, a resin sheet, a fibrous sheet (paper, etc.) can be generally used.

  Of these, fiber sheets such as paper are preferable. Specifically, flame retardant paper (pulp-based sheets treated with flame retardants such as guanidine sulfamate and guanidine phosphate); aluminum hydroxide, magnesium hydroxide Inorganic paper containing inorganic additives such as: high-quality paper; thin paper.

Although the basis weight of the substrate is not critical, preferably about 50 to 300 g / ^{m 2,} about 50 to 80 g / ^{m 2} is more preferable.

Non-foamed resin layer B
In the present invention, a non-foamed resin layer (non-foamed resin layer B) may be formed between the substrate and the foamed resin layer as necessary. In particular, when the non-foamed resin layer B is formed as an adhesive layer, excellent adhesion can be obtained. As the non-foamed resin layer B, for example, ethylene-vinyl acetate copolymer (EVA) or the like can be suitably used.

  The non-foamed resin layer B may contain known additives in addition to the resin component, but is preferably blended so that the content of the resin component is 70 to 100% by weight.

  The thickness of the non-foamed resin layer B is not limited, but is preferably about 10 to 50 μm, more preferably about 10 to 20 μm.

Foamed resin layer The foamed resin layer is formed by foaming a foaming agent-containing resin layer. In particular, in this invention, the foaming agent-containing resin layer, as a resin component, containing a very low density polyethylene low density polyethylene and density 0.85~0.91g / cm ³ of density 0.92~0.95g / cm ³ The ultra low density polyethylene is a mixture of i) ultra low density polyethylene A having 1 to 4 carbon side chains and ii) ultra low density polyethylene B having 6 or more side chains, and the resin. Content of the said ultra-low density polyethylene A and the said ultra-low density polyethylene B in a component is 10 weight% or more, respectively.

Low density polyethylene has a density in the range of 0.92 to 0.95 g / cm ³ . As the low density polyethylene, generally polymerized by a high pressure process can be used.

  The content of the low density polyethylene in the resin component is preferably 50 to 80% by weight. Within the above range, by securing as much content of the low density polyethylene as possible, it is possible to suppress the manufacturing cost while ensuring desired characteristics.

The ultra-low density polyethylene has a density in the range of 0.85 to 0.91 g / cm ³ . As the ultra-low density polyethylene, in the present invention, a mixture of i) ultra-low density polyethylene A having 1 to 4 carbon side chains and ii) ultra low density polyethylene B having 6 or more side chains is used. Such ultra-low density polyethylene is an ethylene / α-olefin copolymer, which is a copolymer of ethylene and at least one α-olefin having 3 to 20 carbon atoms, preferably an α-olefin having 3 to 10 carbon atoms. It is a polymer and its molecular structure is branched with side chains.

  Specific examples of the α-olefin having 3 to 20 carbon atoms used as a comonomer include propylene, 1-butene, 1-pentene, 1-hexene, 4-methylpentene-1, 1-octene, 1-decene, 1-decene, Examples include dodecene. These comonomers can be used individually or in mixture of 2 or more types. Among these comonomers, 1-butene, 1-hexene, and 1-octene are preferable. Moreover, you may contain small amounts of other conomomers, for example, dienes such as 1,6-hexadiene and 1,8-octadiene, cyclic olefins such as cyclopentene, and the like.

  The ultra-low density polyethylene A having a side chain having 1 to 4 carbon atoms may be one in which 97% or more of the carbon number in the side chain is 1 to 4, and more preferably 99 to 99% is 1 to 4. It is most preferable that all side chains have 1 to 4 carbon atoms. In addition, as carbon number, 4 is preferable.

  The ultra-low density polyethylene B having a side chain having 6 or more carbon atoms may be 97% or more of the carbon number of the side chain as long as it is 6 or more, more preferably 99% or more as 6 or more. Most preferably, the side chain has 6 or more carbon atoms. In addition, as carbon number, 6 and 8 are preferable.

  The content of the ultra-low density polyethylene A in the resin component may be 10% by weight or more, but the upper limit is preferably about 25% by weight. That is, the content of the resin component is preferably 10% by weight or more and 25% by weight or less, and more preferably about 15 to 25% by weight. By setting the content of the ultra-low density polyethylene A to 10% by weight or more, the occurrence of curling of the foamed wallpaper can be suppressed.

  The content of the ultra-low density polyethylene B in the resin component may be 10% by weight or more, but the upper limit is preferably about 25% by weight. That is, the content of the resin component is preferably 10% by weight or more and 25% by weight or less, and more preferably about 15 to 25% by weight. By setting the content of the ultra-low density polyethylene B to 10% by weight or more, occurrence of cracks in the foam wallpaper can be suppressed.

  The resin component contained in the foaming agent-containing resin layer may be generally composed of the three components of the low density polyethylene, the ultra low density polyethylene A, and the ultra low density polyethylene B. More specifically, it is preferable to blend about 50 to 80% by weight of low density polyethylene, about 10 to 25% by weight of ultra low density polyethylene A, and about 10 to 25% by weight of ultra low density polyethylene B.

  As the foaming agent contained in the foaming agent-containing resin layer, a pyrolytic foaming agent is preferable. For example, an azodicarbonamide (ADCA) foaming agent, an oxybisbenzenesulfonyl hydrazide (OBSH) foaming agent, or the like can be used. Among these, ADCA-based foaming agents are preferable from the viewpoint of high film-forming properties because of their high thermal decomposition temperature, and low risk of abnormal foaming during extrusion film formation.

  The content of the pyrolytic foaming agent can be appropriately set according to the type of foaming agent, the expansion ratio, and the like. From the viewpoint of the expansion ratio, it is 1.5 times or more, preferably about 3 to 7 times, and the pyrolytic foaming agent is preferably about 0.01 to 20 parts by weight with respect to 100 parts by weight of the resin component, About 0.1-10 weight part is more preferable.

  Various additives may be added to the foaming agent-containing resin layer. For example, inorganic fillers, pigments and foam stabilizers, antioxidants, zinc compounds, crosslinking agents, surface treatment agents, fluorescent whitening agents, fungicides, lubricants, and the like can be used as additives.

  Examples of the inorganic filler include calcium carbonate, aluminum hydroxide, magnesium hydroxide, antimony trioxide, zinc borate, and a molybdenum compound. By including an inorganic filler, an effect of suppressing see-through, an effect of improving surface characteristics, and the like are obtained. About 0-100 weight part is preferable with respect to 100 weight part of resin components, and, as for content of an inorganic filler, about 20-70 weight part is more preferable.

  As for pigments, for example, titanium oxide, zinc white, carbon black, black iron oxide, yellow iron oxide, yellow lead, molybdate orange, cadmium yellow, nickel titanium yellow, chrome titanium yellow, iron oxide (valve), cadmium red Inorganic pigments such as ultramarine, bitumen, cobalt blue, chromium oxide, cobalt green, aluminum powder, bronze powder, titanium mica, and zinc sulfide; for example, aniline black, perylene black, azo (azo lake, insoluble azo, condensed azo), Polycyclic (isoindolinone, isoindoline, quinophthalone, perinone, flavantron, anthrapyrimidine, anthraquinone, quinacridone, perylene, diketopyrrolopyrrole, dibromoanthanthrone, dioxazine, thioindigo, phthalocyanine, indanthro , And organic pigments halogenated phthalocyanine), or the like. The content of the pigment is preferably about 10 to 50 parts by weight and more preferably about 15 to 30 parts by weight with respect to 100 parts by weight of the resin component.

  Examples of the foam stabilizer include alkyl sulfonate and alkyl benzene sulfonate. Specifically, at least one of sodium dodecylbenzenesulfonate and calcium dodecylbenzenesulfonate is preferable.

  Further, a metal soap such as zinc stearate and a surfactant can be used. These contents are preferably about 0.3 to 10 parts by weight, and more preferably about 1 to 5 parts by weight with respect to 100 parts by weight of the resin component.

  Examples of the antioxidant include 2,6-ditert-butyl-p-cresol and tetrakis [methylene-3 (3,5-di-tert-butyl-4-hydroxy-phenyl), which are phenolic antioxidants. Propionate] methane, phosphorous antioxidant tris (2,4-di-butylphenyl) phosphite, distearyl pentaerythritol diphosphite and the like.

  Examples of the zinc compound include zinc oxide, hydroxide, carbonate, basic carbonate, sulfate, nitrate, phosphite, carboxylate and the like. Such a zinc compound is preferably added from the viewpoint of improving the foaming speed. Examples of the carboxylate include acetic acid, propionic acid, 2-ethylhexanoic acid, nonanoic acid, isononanoic acid, isodecanoic acid, neodecanoic acid, lauric acid, myristic acid, palmitic acid, stearic acid, isostearic acid, oleic acid, Examples include aliphatic acids such as 12-hydroxystearic acid, ricinoleic acid, and behenic acid, and aromatic acids such as benzoic acid, p-tert-butylbenzoic acid, toluic acid, salicylic acid, and naphthenic acid. The zinc carboxylate using these carboxylic acids may be in the form of a normal salt, an acid salt, or a basic salt. The above-mentioned carboxylic acids constituting the zinc carboxylate can be used, but from the viewpoint of reducing VOC, those which are powders at room temperature using fatty acids having 12 or more carbon atoms, such as zinc stearate And zinc laurate are preferred. When other carboxylic acid is used, it may be liquid or may need to be dissolved in an organic solvent in order to improve handling properties.

  The content of the zinc compound is preferably about 0.001 to 20 parts by weight, more preferably about 0.001 to 10 parts by weight with respect to 100 parts by weight of the resin composition. The thickness of the foamed layer is not limited, but is preferably 70 to 150 μm in a non-foamed state (before foaming). 300-900 micrometers is preferable after foaming.

  What is necessary is just to implement according to the method described in the manufacturing method of the postscript as a method of foaming a foaming agent containing resin layer. In addition, generation | occurrence | production of the crack of a foamed resin layer can be suppressed more reliably by irradiating an electron beam before foaming a foaming agent containing resin layer.

Non-foamed resin layer A
A non-foamed resin layer A may be further formed on the front surface of the foamed resin layer.

The non-foamed resin layer (non-foamed resin layer A) mainly protects the foamed resin layer. In the present invention, a layer formed of a resin composition containing, as a resin component, a polymer obtained using at least one of acrylic acid (CH ₂ ═CHCOOH) and methacrylic acid (CH ₂ ═C (CH ₃ ) COOH) as a monomer. Is preferably a non-foamed resin layer.

  As the resin component, for example, a copolymer obtained by a combination of at least one monomer of acrylic acid and methacrylic acid and ethylene can be suitably used as the resin component. More specifically, it is desirable to use at least one of EMAA, ethylene-acrylic acid copolymer, and ionomer resin. As the ionomer resin, a resin having a structure in which EMAA and / or ethylene-acrylic acid copolymer molecules are intermolecularly bonded with metal ions such as sodium and zinc can be used. When such a resin component is used, it is possible to form a strong layer particularly due to hydrogen bonds in the resin, so that excellent scratch resistance, abrasion resistance, and the like can be obtained. These may be known or commercially available.

  The content of acrylic acid or methacrylic acid in the copolymer is not limited, but is preferably 15% by weight or less, more preferably about 4 to 15% by weight. Such a resin can also use a commercial item. A known additive can also be blended in the resin composition.

  The thickness of the non-foamed resin layer is not limited, but is preferably about 10 to 50 μm, more preferably about 10 to 20 μm.

  Although the melt flow rate value of the resin component depends on the type of the resin component to be used, etc., it is generally set as appropriate within a range of 10 g / 10 min or more. Usually, it is preferably 10 to 100 g / 10 minutes, particularly preferably 10 to 95 g / 10 minutes, and more preferably 20 to 80 g / 10 minutes. By using a material having such a numerical range, more excellent scratch resistance, wear resistance and the like can be obtained.

  Moreover, although content of the said resin component in a resin composition is not limited, Usually, it is preferable to set suitably in the range of 70 to 100 weight%.

Pattern Pattern Layer In the present invention, a pattern pattern layer may be provided on the front surface of the non-foamed resin layer A as necessary.

  The pattern layer imparts design properties to the foamed wallpaper. Examples of the design pattern include a wood grain pattern, a stone pattern, a grain pattern, a tiled pattern, a brickwork pattern, a cloth pattern, a leather pattern, a geometric figure, a character, a symbol, and an abstract pattern. The pattern can be selected according to the type of foam wallpaper.

  The pattern pattern layer can be formed, for example, by printing a pattern pattern on the front surface of the non-foamed resin layer A. In addition, when forming a picture pattern layer, you may form a primer layer previously as needed. Examples of printing methods include gravure printing, flexographic printing, silk screen printing, and offset printing. As the printing ink, a printing ink containing a colorant, a binder resin, and a solvent (or a dispersion medium) can be used. These inks may be known or commercially available.

  As the colorant, for example, a pigment used in the above-described foaming agent-containing resin layer can be appropriately used.

  The binder resin is, for example, an acrylic resin, a styrene resin, a polyester resin, a urethane resin, a chlorinated polyolefin resin, a vinyl chloride-vinyl acetate copolymer resin, a polyvinyl butyral resin, an alkyd resin, or a petroleum resin. Examples include resins, ketone resins, epoxy resins, melamine resins, fluorine resins, silicone resins, fiber derivatives, rubber resins, and the like.

  Examples of the solvent (or dispersion medium) include petroleum organic solvents such as hexane, heptane, octane, toluene, xylene, ethylbenzene, cyclohexane, and methylcyclohexane; ethyl acetate, butyl acetate, 2-methoxyethyl acetate, and acetic acid-2 -Ester-based organic solvents such as ethoxyethyl; alcohol-based organic solvents such as methyl alcohol, ethyl alcohol, normal propyl alcohol, isopropyl alcohol, isobutyl alcohol, ethylene glycol, propylene glycol; ketones such as acetone, methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone Organic solvents; ether organic solvents such as diethyl ether, dioxane, tetrahydrofuran; dichloromethane, carbon tetrachloride, trichloroethylene, tetrachloroethylene Chlorinated organic solvents; and water.

  The thickness of the design pattern layer is different from the type of design pattern, but is generally preferably about 0.1 to 10 μm.

Surface protective layer (overcoat layer)
In the present invention, a surface protective layer may be provided on the surface of the design pattern layer for the purpose of adjusting the gloss and / or protecting the design pattern layer. The kind of surface protective layer is not limited. If it is a surface protective layer aiming at gloss adjustment, there exists a surface protective layer containing known fillers, such as a silica, for example. As a method for forming the surface protective layer, a known method such as gravure printing can be employed. In addition, when the adhesiveness of a pattern pattern layer and a surface protective layer is not fully acquired, a surface protective layer can also be provided after carrying out the adhesion process (primer process) of the surface of a pattern pattern layer.

  When forming a surface protective layer for the purpose of surface strength (such as scratch resistance) of foamed wallpaper, stain resistance, protection of the pattern layer, etc., those containing ionizing radiation curable resins as resin components are suitable. is there. The ionizing radiation curable resin is preferably one that undergoes radical polymerization (curing) by electron beam irradiation.

  The thickness of the surface protective layer is not limited, but is preferably about 0.1 to 15 μm.

Embossing In this invention, you may attach | subject an embossing pattern suitably. In this case, what is necessary is just to emboss from the outermost surface layer (an opposite side to a base material) of a foam wallpaper. Embossing can be performed by known means such as pressing an embossed plate. For example, when the outermost surface layer is a surface protective layer, a desired embossed pattern can be formed by pressing the embossed plate after heat-softening the front surface. Examples of the embossed pattern include a wood grain plate conduit groove, a stone plate surface unevenness, a cloth surface texture, a satin texture, a grain texture, a hairline, and a multiline groove.

<Method for producing foam wallpaper>
The method for producing the foam wallpaper is not particularly limited. For example, in order to produce a foamed wallpaper having a foamed resin layer and a non-foamed resin layer A on a substrate such as paper, coextrusion by a T-die extruder is suitable. A multi-manifold type T-die capable of simultaneously forming two layers by simultaneously extruding molten resin corresponding to two layers can be used. In this case, the resin composition for forming the foaming agent-containing resin layer and the resin composition for forming the non-foamed resin layer are placed in separate cylinders, and two types and two layers are simultaneously extruded to form and laminate. That's fine. In this method, the coextruded laminate is simultaneously laminated (film formation) on the substrate. Since the resin layer laminated simultaneously with extrusion on the base material has adhesiveness by heat melting, it is bonded to the base material.

  In addition, a laminate in which two types and two layers are simultaneously formed in advance may be prepared, placed on the substrate, and bonded to the substrate by thermal lamination.

  In addition, when an inorganic filler is contained in the resin composition forming the foaming agent-containing resin layer, an inorganic filler residue (so-called eyes) is easily generated at the extrusion port (so-called die) of the extrusion molding machine. It tends to be a foreign material on the sheet surface. Therefore, when the inorganic filler is contained in the resin composition forming the foaming agent-containing resin layer, the non-foaming resin layer A and the non-foaming resin layer B can be coextruded together with the foaming agent-containing resin layer. preferable. The coextrusion molding can be performed, for example, by using a multi-manifold type T die. Thus, by simultaneously extruding and molding the foaming agent-containing resin layer between the non-foamed resin layers, it is possible to suppress the occurrence of the eyes.

  After simultaneous lamination on the substrate, the foamed resin layer is formed by heating the foaming agent-containing resin layer. The heating conditions are not limited as long as the foamed resin layer is formed by the decomposition of the pyrolytic foaming agent. The heating temperature is preferably about 210 to 240 ° C., and the heating time is preferably about 20 to 80 seconds.

  Electron beam irradiation may be performed before the heat treatment. Thereby, since the resin component can be crosslinked, the surface strength of the foamed wallpaper, the degree of foaming, and the like can be controlled. In particular, the generation of cracks in the foamed resin layer can be more reliably suppressed by irradiating the foaming agent-containing resin layer with an electron beam. The energy of the electron beam is preferably about 150 to 250 kV. The irradiation amount is preferably about 1 to 7 Mrad. A known electron beam irradiation apparatus can be used as the electron beam source. The crosslinking can also be performed using a chemical crosslinking agent (also referred to as a crosslinking agent or a crosslinking aid).

  In the case of performing electron beam irradiation, the composition may contain a crosslinking agent. Any crosslinking agent that promotes crosslinking by electron beam irradiation may be used. Examples thereof include polyfunctional monomers such as neopentyl glycol dimethacrylate and trimethylolpropane trimethacrylate, oligomers, and the like. The crosslinking agent is preferably about 0 to 10 parts by weight, more preferably 1 to 4 parts by weight, based on 100 parts by weight of the resin component.

  When a surface protective layer containing an ionizing radiation curable resin is formed, the surface protective layer can be cured by electron beam irradiation. Such electron beam irradiation can be performed simultaneously (same processing) as electron beam irradiation performed to crosslink the resin contained in the foaming agent-containing resin layer. That is, after forming a foaming agent-containing resin layer, a non-foaming resin layer, a pattern layer, and a surface protective layer containing an ionizing radiation curable resin in this order, the resin contained in the foaming agent-containing resin layer is irradiated with an electron beam. The resin contained in the surface protective layer can be cured while being crosslinked.

  When producing a foam wallpaper having a pattern layer, it is preferable to form the pattern layer on the surface of the non-foamed resin layer before the heat treatment. The pattern pattern layer may be formed as described above.

  The foam wallpaper of the present invention contains low-density polyethylene and ultra-low-density polyethylene as resin components contained in the foam-containing resin layer, and particularly ultra-low-density polyethylene A and ultra-low-density polyethylene B that are specific as ultra-low density polyethylene. Therefore, curling and cracking of the foamed wallpaper are suppressed. In addition, since practical surface strength is ensured and the content of ultra-low density polyethylene is set as low as possible by 10% by weight or more, the production cost can be suppressed, so that general-purpose foaming is possible. Become wallpaper.

  Hereinafter, the present invention will be described in more detail with reference to Examples and Comparative Examples. However, the present invention is not limited to the examples.

Example 1
A backing paper “NI-65A (made by Nippon Paper Industries)” was prepared as a substrate.

  In order to form the foaming agent-containing resin layer, the resin compositions shown in Table 1 below were prepared.

[In Table 1, LDPE indicates low density polyethylene. VLDPE-A refers to very low density polyethylene A. VLDPE-B indicates very low density polyethylene B. Hereinafter, in Comparative Examples 1 to 5, the same notation indicates the same substance. ]
The resin composition was melted in a cylinder and extruded to form a 100 μm foaming agent-containing resin layer on the substrate. The T die used for extrusion film formation had a cylinder temperature and a die temperature of 135 ° C.

  Next, the laminate on which the foaming agent-containing resin layer was formed was heated in a gear oven (25 to 45 seconds at 220 ° C.) to foam the foaming agent-containing resin layer. A foamed wallpaper was produced through the above steps.

Example 2
A foamed wallpaper was prepared in the same manner as in Example 1 except that VLDPE-B was changed to “ENGAGE 8407, side chain carbon number 8, density 0.87 g / cm ³ , (manufactured by Dow Chemical)”.

Comparative Example 1
A foamed wallpaper was prepared in the same manner as in Example 1 except that the resin component was composed of only 100 parts by weight of EVA “V406 (Mitsui / DuPont)”.

Comparative Example 2
A foam wallpaper was prepared in the same manner as in Example 1 except that the resin component was composed only of 100 parts by weight of LDPE.

Comparative Example 3
A foam wallpaper was produced in the same manner as in Example 1 except that the resin component was composed of only 100 parts by weight of VLDPE-A.

Comparative Example 4
A foamed wallpaper was prepared in the same manner as in Example 1 except that the resin component was composed of 80 parts by weight of LDPE and 20 parts by weight of VLDPE-A.

Comparative Example 5
A foamed wallpaper was prepared in the same manner as in Example 1 except that the resin component was composed of 80 parts by weight of LDPE and 20 parts by weight of VLDPE-B.

Example 3
Using a two-type two-layer multi-manifold T-die extruder, i) a non-foamed resin layer / ii) a foaming agent-containing resin layer were co-extruded to form a thickness of 15 μm / 100 μm. The backing paper was laminated. Extrusion conditions were as follows: i) layer resin had a cylinder temperature of 180 ° C. and a die temperature of 120 ° C., and ii) layer resin had a cylinder temperature and die temperature of 135 ° C. Next, the i) layer was irradiated with an electron beam (175 KV 5 Mrad) to crosslink the resin, and the i) layer was subjected to corona discharge treatment. Further, 2 g / m ² of EVA water-based emulsion was applied as a primer treatment by a gravure printing machine, and a fabric pattern was printed thereon using a water-based ink “Hydric (manufactured by Dainichi Seika Kogyo)” as a pattern print. Next, it was heated in a gear oven (220 ° C. × 35 seconds) to foam the foaming agent-containing resin layer. The foam was further embossed with a textured pattern. A foamed wallpaper was produced through the above steps.

The resin composition for forming the backing paper and the foaming agent-containing resin layer was the same as in Example 1.
The layer i) was formed from an ethylene-methacrylic acid copolymer “Nucleel N1035 (MFR = 35): made by Mitsui DuPont Polychemicals”.

Test example 1
The foamed wallpaper produced in the examples and comparative examples was evaluated in terms of curling, cracking, and surface strength. Evaluation methods and evaluation criteria were as follows.

  Curl: The foamed wallpaper was cut into a rectangle of 10 cm in the width direction and 5 cm in the flow direction, immersed in water, and then examined for the presence of curl when dried.

○: Curling is not recognized, or the end faces upward. ×: Both ends stick together due to curling. Crack: A foamed wallpaper was attached to a right-angle jig and observed under the assumption of a corner of the column.

○: No cracks are observed ×: Cracks are observed throughout the surface Strength: Ten reciprocation scratch tests were performed at a load of 200 g according to the surface strengthening performance test (Japan Vinyl Industry Association).

○: Slight scratches are observed after 10 round trips. Δ: Clear scratches are found after 10 round trips. ×: Resin layer is scratched until the backing paper is visible after less than 10 round trips. Shown in

  As is apparent from the results in Table 2, the foamed wallpaper (Examples 1, 2 and 3) of the present invention has curling and cracking suppressed and practical surface strength is ensured. Furthermore, since ultra-low density polyethylenes A and B are each used only in a content of 10% by weight, the production cost of foamed wallpaper is reduced, and versatility is high.

Claims (6)

A foam wallpaper having at least a foam resin layer on a substrate,
(1) The foamed resin layer is formed by foaming a foaming agent-containing resin layer,
(2) the blowing agent-containing resin layer, as a resin component, containing a low-density polyethylene and very low density polyethylene having a density of 0.85~0.91g / cm ³ of density 0.92~0.95g / cm ³ The ultra low density polyethylene is a mixture of i) ultra low density polyethylene A having 1 to 4 carbon side chains and ii) ultra low density polyethylene B having 6 or more side chains,
(3) The contents of the ultra-low density polyethylene A and the ultra-low density polyethylene B in the resin component are each 10% by weight or more.
Foam wallpaper characterized by that.   The foamed wallpaper according to claim 1, wherein the contents of the ultra-low density polyethylene A and the ultra-low density polyethylene B in the resin component are 10 wt% or more and 25 wt% or less, respectively.   The foamed wallpaper according to claim 1 or 2, wherein a non-foamed resin layer A is further formed on the front surface of the foamed resin layer.   The foamed wallpaper according to any one of claims 1 to 3, wherein a non-foamed resin layer B is further formed between the base material and the foamed resin layer.   The foamed wallpaper according to claim 3 or 4, wherein the non-foamed resin layer A contains an ethylene-methacrylic acid copolymer having a methacrylic acid content of 15 wt% or less as a resin component.   The foamed wallpaper according to any one of claims 1 to 5, wherein embossing is performed on the outermost surface layer.