JP5252111B2 - Laminated body before foaming of foam wallpaper - Google Patents

Description

  The present invention relates to foamed wallpaper useful for wall decoration.

  Conventionally, foamed wallpaper (foamed decorative sheet) is known in which a foamed resin layer of vinyl chloride resin is formed on a paper-based substrate (backing paper). In recent years, in consideration of the environment, resins that do not contain halogen such as ethylene-vinyl acetate copolymer resin (EVA), acrylic resin, and olefin resin have been used for the foamed resin layer (Patent Document 1). ~ 3 etc.).

  The foamed wallpaper is generally obtained by forming a foaming agent-containing resin layer on a paper base and then foaming the foaming agent-containing resin layer by heating. As a method for forming a foaming agent-containing resin layer, there are a calendering method and an extrusion method using a T die. Among these, a method of extruding a melted resin composition with a T die is known as a simple method. ing.

  When the foaming agent-containing resin layer is formed by extrusion film formation, a resin having a low melting point and a high MFR (melt flow rate) is generally used as a resin component in terms of facilitating extrusion. As such a resin, an ethylene copolymer such as EVA is suitable, and for example, it is formed by extrusion using a resin composition containing EVA, a pyrolytic foaming agent and an inorganic filler such as calcium carbonate. In addition, an inorganic filler such as calcium carbonate is a filler for relatively reducing the resin component, and is blended into the resin composition in order to reduce manufacturing costs.

  However, since the foaming agent-containing resin layer formed using an ethylene copolymer has insufficient melt tension, it is necessary to increase the melt tension by electron beam irradiation prior to the foaming step. As described above, since the melt tension can be adjusted by electron beam irradiation, the foaming characteristics of the foamed resin layer can be improved, but the calcium carbonate as the filler is discolored by electron beam irradiation and the design of the foam wallpaper is reduced. Has been pointed out.

  When calcium carbonate is not used, the above problem of discoloration is avoided. However, from the viewpoint of reducing the manufacturing cost, it is required to avoid the above problem by eliminating electron beam irradiation while keeping calcium carbonate blended. ing.

  Accordingly, a foaming agent-containing resin layer is formed by extruding and forming a resin composition containing an ethylene copolymer and calcium carbonate, and sufficient melt tension can be obtained without irradiating an electron beam prior to the foaming step. Therefore, it is desired to develop a foamed wallpaper in which a good foamed state is formed by foaming it.

Japanese Patent Laid-Open No. 6-47875 JP 2000-255011 A JP 2001-347611 A

The present invention forms a foaming agent-containing resin layer by extruding and forming a resin composition containing an ethylene copolymer and calcium carbonate, and has a sufficient melt tension even without electron beam irradiation prior to the foaming step. An object of the present invention is to provide a foamed wallpaper which is obtained and foamed to form a good foamed state.

  As a result of intensive studies, the present inventor has found that the above object can be achieved when a specific calcium carbonate is used as the inorganic filler contained in the foaming agent-containing resin layer, and the present invention has been completed.

That is, this invention relates to the laminated body before foaming of the following foaming wallpaper.
1. A laminate prior to foaming of foamed wallpaper having at least a foaming agent-containing resin layer on a paper-based substrate,
(1) The foaming agent-containing resin layer is formed by extrusion film formation,
(2) The foaming agent-containing resin layer contains an ethylene copolymer having an MFR of 20 to 45 g / 10 min as a resin component, and is an average particle surface-treated with a fatty acid with respect to 100 parts by weight of the resin component Containing 10 to 100 parts by weight of calcium carbonate having a diameter of 2 to 10 μm,
A laminate before foaming of foamed wallpaper characterized by the above.
2. The laminate of the foamed wallpaper before foaming according to Item 1, wherein the ethylene copolymer is an ethylene-vinyl acetate copolymer.
3. Item 2. The laminated body before foaming of the foamed wallpaper according to Item 1, wherein the ethylene copolymer is an ethylene-methacrylic acid copolymer.
4). Item 4. The laminate before foaming of the foamed wallpaper according to any one of Items 1 to 3, wherein the fatty acid is a higher fatty acid.
5. Item 5. The laminated body before foaming of foamed wallpaper according to any one of Items 1 to 4, wherein a non-foamed resin layer A is further formed on the front surface of the foaming agent-containing resin layer.
6). The said non-foaming resin layer A is a laminated body before foaming of the foaming wallpaper of the said claim | item 5 containing the ethylene-methacrylic acid copolymer whose methacrylic acid content is 15 weight% or less as a resin component.
7. Item 7. The laminated body before foaming of foamed wallpaper according to any one of Items 1 to 6, wherein a non-foamed resin layer B is further formed between the paper substrate and the foaming agent-containing resin 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 a paper-based substrate,
(1) The foamed resin layer is formed by foaming the foaming agent-containing resin layer after forming the foaming agent-containing resin layer by extrusion film formation,
(2) The foaming agent-containing resin layer contains an ethylene copolymer as a resin component, and calcium carbonate having an average particle diameter of 1 to 10 μm surface-treated with a fatty acid with respect to 100 parts by weight of the resin component. It contains 10 to 100 parts by weight.

  Since the foamed wallpaper of the present invention having the above characteristics contains an ethylene copolymer as a resin component contained in the foaming agent-containing resin layer, extrusion film formation is easy. Moreover, since calcium carbonate surface-treated with a fatty acid is used as calcium carbonate (inorganic filler) combined with the resin component, even if blended in an amount of 10 to 100 parts by weight with respect to 100 parts by weight of the resin component, the extrusion characteristics are not affected. The melt tension of the foaming agent-containing resin layer can be sufficiently secured. Therefore, it is not necessary to perform electron beam irradiation prior to the foaming step, and the problem of discoloration of calcium carbonate due to electron beam irradiation is also solved.

  Hereinafter, each requirement will be described separately.

The material of the paper base is not particularly limited as long as it has mechanical strength, heat resistance and the like suitable as a wallpaper base, and a fiber sheet can be generally used.

  Specifically, among fiber sheets, flame retardant paper (pulp-based sheets treated with flame retardants such as guanidine sulfamate and guanidine phosphate); inorganic additives such as aluminum hydroxide and magnesium hydroxide Inorganic paper including; fine paper; thin paper and the like.

The basis weight of the paper quality substrate is not limited, but 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 paper 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, an ethylene-vinyl acetate copolymer 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 5 to 50 μm, more preferably about 8 to 20 μm.

Foamed resin layer The foamed resin layer is formed by foaming the foaming agent-containing resin layer after forming the foaming agent-containing resin layer by extrusion film formation. The foaming agent used in the present invention is preferably a pyrolytic foaming agent. In this case, the foaming agent-containing resin layer is foamed by heating to become a foamed resin layer.

  In the present invention, the foaming agent-containing resin layer contains an ethylene copolymer as a resin component, and calcium carbonate having an average particle diameter of 1 to 10 μm surface-treated with a fatty acid with respect to 100 parts by weight of the resin component. Contains 10 to 100 parts by weight.

  The ethylene copolymer is suitable for extrusion film formation from the viewpoint of melting point and MFR. Examples of the ethylene copolymer include ethylene-vinyl acetate copolymer (EVA), ethylene-methyl methacrylate copolymer (EMMA), ethylene-ethyl acrylate copolymer (EEA), ethylene-methyl acrylate copolymer ( EMA) and ethylene-methacrylic acid copolymer (EMAA). These ethylene copolymers can be used alone or in admixture of two or more. Among these ethylene copolymers, ethylene-vinyl acetate copolymer and ethylene-methacrylic acid copolymer are particularly preferable. When any one of these is used in combination with one or more other resins, ethylene -The content of vinyl acetate copolymer and ethylene-methacrylic acid copolymer is preferably 70% by weight or more, and more preferably 80% by weight or more.

  The MFR of the ethylene copolymer is preferably 15 to 50 g / 10 minutes, and more preferably 20 to 45 g / 10 minutes. By adopting such MFR, the extrusion film forming property is further enhanced. In addition, MFR of this specification is the value measured by the test method of JISK7210 (flow test method of thermoplastics). As test conditions, “190 ° C., 21.18 N (2.16 kgf)” described in JIS K 6760 is adopted.

  The ethylene-vinyl acetate copolymer has a vinyl acetate copolymerization ratio (VA amount) of preferably 10 to 30% by weight, and more preferably 15 to 25% by weight. By adopting such a copolymerization ratio, the extrusion film forming property is further enhanced.

  The ethylene-methacrylic acid copolymer is preferably 1 to 30% by weight, more preferably 5 to 15% by weight, as the copolymerization ratio (MA amount) of methacrylic acid. By adopting such a copolymerization ratio, the extrusion film forming property is further enhanced.

  In the present invention, calcium carbonate surface-treated with a fatty acid is used as the inorganic filler. The fatty acid is preferably a higher fatty acid, and specific examples include stearic acid, lauric acid, oleic acid and the like. Examples of the surface-treated calcium carbonate include “trade names“ PLUS ONE ”and“ Whiteon 305 ”, both manufactured by Toyo Fine Chemical Co., Ltd.”.

  As the surface-treated calcium carbonate, one having an average particle diameter of 1 to 10 μm is used. Among these, 2 to 5 μm is preferable. This average particle diameter is a value measured by microtrack particle size analysis. By combining the surface treatment with a fatty acid and such an average particle size, even if the blending amount of calcium carbonate in the foaming agent-containing resin layer is increased to 100 parts by weight, the extrusion characteristics are hardly impaired.

  The pyrolytic foaming agent can be selected from known foaming agents. Examples include azo series such as azodicarbonamide (ADCA) and azobisformamide; hydrazide series such as oxybenzenesulfonyl hydrazide (OBSH) and paratoluenesulfonyl hydrazide. The content of the pyrolytic foaming agent is set according to the type of foaming agent and the foaming ratio. 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 1 to 20 parts by weight with respect to 100 parts by weight of the resin component. .

  An additive may be added to the foaming agent-containing resin layer as long as the effect of the present invention is not affected. For example, pigments and foam stabilizers, antioxidants, foaming aids (zinc compounds), crosslinking agents, surface treatment agents, fluorescent whitening agents, fungicides, lubricants, and the like can be used as additives.

  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, bituminous, cobalt blue, chromium oxide, cobalt green, aluminum powder, bronze powder, titanium mica, 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 foaming aid (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.

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 the non-foamed resin layer A.

  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 A is not limited, but is preferably about 5 to 50 μm, more preferably about 8 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, and 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, embossing may be performed on the outermost surface layer (the side opposite to the paper-based substrate) of the 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 foamed wallpaper may be produced by any method as long as the foaming agent-containing resin layer is foamed after forming the foaming agent-containing resin layer by extrusion film formation. For example, in order to produce a foamed wallpaper having a foamed resin layer and a non-foamed resin layer A on a paper substrate, coextrusion with 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 A are placed in separate cylinders, and two types and two layers are simultaneously extruded to form and laminate. do it. In this method, the coextruded laminate is simultaneously laminated (film formation) on a paper-based substrate. The resin layer laminated simultaneously with extrusion on the paper base is bonded to the paper base because it has adhesiveness by heat melting.

  In the present invention, since calcium carbonate is contained in the foaming agent-containing resin layer, calcium carbonate residues (so-called eyes) are likely to adhere to the extrusion port (so-called die) of the extrusion molding machine, and this tends to be a foreign matter on the sheet surface. Therefore, in the case of this invention, it is preferable to coextrude the said non-foamed resin layer A and the non-foamed resin layer B with the foaming agent containing resin layer. 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 paper 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 200 to 250 ° C, more preferably about 210 to 240 ° C. The heating time is preferably about 20 to 60 seconds, and more preferably about 30 to 50 seconds.

  In the present invention, since a predetermined amount of calcium carbonate surface-treated with a higher fatty acid is contained in the foaming agent-containing resin layer, it is not necessary to perform electron beam irradiation prior to the foaming step. That is, since the surface tension of the foaming agent-containing resin layer is obtained by using calcium carbonate, good foaming characteristics can be obtained without electron beam irradiation.

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

  Since the foamed wallpaper of the present invention contains an ethylene copolymer as a resin component contained in the foaming agent-containing resin layer, extrusion film formation is easy. Moreover, since calcium carbonate surface-treated with a fatty acid is used as calcium carbonate (inorganic filler) combined with the resin component, even if blended in an amount of 10 to 100 parts by weight with respect to 100 parts by weight of the resin component, the extrusion characteristics are not affected. The melt tension of the foaming agent-containing resin layer can be sufficiently secured. Therefore, it is not necessary to perform electron beam irradiation prior to the foaming step, and the problem of discoloration of calcium carbonate due to electron beam irradiation is also solved.

  The present invention will be specifically described below with reference to examples and comparative examples. However, the present invention is not limited to the examples.

Example 1
A foaming agent-containing resin layer having the composition shown in Table 1 below is formed on a paper base material (product number “WK665DO”, manufactured by Kojin, thickness 110 μm) by extrusion film formation, and foamed by foaming it by heating. I made a wallpaper.

  The foam wallpaper was produced by the following procedure.

  The resin composition of the above components 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 of 100 ° C. and a die temperature of 120 ° 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 foaming agent-containing resin layer having the composition shown in Table 2 below is formed on a paper base material (product number “WK665DO”, manufactured by Kojin, thickness 110 μm) by extrusion film formation, and foamed by foaming it by heating. I made a wallpaper.

  The foam wallpaper was produced by the following procedure.

  The resin composition of the above components was melted in a cylinder and extruded to form a 110 μm foaming agent-containing resin layer on the substrate. The T-die used for extrusion film formation had a cylinder temperature of 110 ° C. and a die temperature of 120 ° 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 about 5 times. A foamed wallpaper was produced through the above steps.

Comparative Example 1
A foamed wallpaper was prepared in the same manner as in Example 1 except that calcium carbonate that was not surface-treated “average particle size: 22 μm, trade name (Whiteon H), manufactured by Toyo Fine Chemical Co., Ltd.” was used as calcium carbonate. .

Comparative Example 2
Foamed wallpaper in the same manner as in Example 1 except that calcium carbonate that has not been surface-treated, “average particle diameter: 3.0 μm, trade name (Whiteon P-10), (manufactured by Toyo Fine Chemical)” was used as calcium carbonate. Was made.

Comparative Example 3
A foamed wallpaper was prepared in the same manner as in Example 2 except that calcium carbonate that was not surface-treated “average particle size: 22 μm, trade name (Whiteon H), manufactured by Toyo Fine Chemical Co., Ltd.” was used as calcium carbonate. .

Comparative Example 4
A foamed wallpaper was prepared in the same manner as in Example 2 except that calcium carbonate was not used.

Test example 1
The foamed wallpaper produced in Examples and Comparative Examples was evaluated for 1) quality of extrusion film formation, 2) quality of foaming characteristics, and 3) color tone of the foamed resin layer.

(Extruded film formation)
A case where there was no abnormal foaming during extrusion film formation, and there was no abnormal foaming and was easy to extrude was evaluated as ◯, and a case where abnormal foaming was observed was evaluated as x.

(Cell evaluation of foamed resin layer)
The cell state was evaluated by visually observing the surface of the foamed resin layer.

  Specifically, the cell expands on the surface of the foamed resin layer (a blister-like swell, which occurs when the gas generated by thermal decomposition has a gas pressure exceeding the critical point of the melt tension of the resin. Evaluation was made based on whether or not the resin layer surface smoothness was impaired. As the evaluation criteria, a case where the occurrence rate of swelling on the surface of the foamed resin layer was 0 to less than 10% was evaluated as “◯”, a case where it was 10% or more and less than 50%, and a case where it was 50% or more.

  The evaluation results are shown in Table 3 below.

  As is clear from the results in Table 3, the foamed wallpaper of the present invention can be easily formed into an extruded film during the production process, and the foamed resin layer has good foaming characteristics. And since it is not necessary to perform electron beam irradiation prior to a foaming process, discoloration of calcium carbonate is also prevented. Since the comparative example 4 does not use calcium carbonate, the predetermined whiteness of the foamed resin layer is not obtained.

Claims (7)

A laminate prior to foaming of foamed wallpaper having at least a foaming agent-containing resin layer on a paper-based substrate,
(1) The foaming agent-containing resin layer is formed by extrusion film formation,
(2) The foaming agent-containing resin layer contains an ethylene copolymer having an MFR of 20 to 45 g / 10 min as a resin component, and is an average particle surface-treated with a fatty acid with respect to 100 parts by weight of the resin component Containing 10 to 100 parts by weight of calcium carbonate having a diameter of 2 to 10 μm,
A laminate before foaming of foamed wallpaper characterized by the above.   The laminate of the foamed wallpaper before foaming according to claim 1, wherein the ethylene copolymer is an ethylene-vinyl acetate copolymer.   The laminate of the foamed wallpaper before foaming according to claim 1, wherein the ethylene copolymer is an ethylene-methacrylic acid copolymer.   The laminate of the foamed wallpaper before foaming according to any one of claims 1 to 3, wherein the fatty acid is a higher fatty acid.   The laminated body before foaming of the foaming wallpaper in any one of Claims 1-4 in which the non-foaming resin layer A is further formed in the front surface of the said foaming agent containing resin layer.   The said non-foaming resin layer A is a laminated body before foaming of the foam wallpaper of Claim 5 which contains the methacrylic acid content of 15 weight% or less ethylene-methacrylic acid copolymer as a resin component.   The laminated body before foaming of the foaming wallpaper in any one of Claims 1-6 in which the non-foaming resin layer B is further formed between the said paper-like base material and the said foaming agent containing resin layer.