JP2012213939A - Method for producing laminated sheet and foamed laminated sheet - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a foamed laminated sheet improved in contamination resistance and scratch resistance, and a novel manufacturing method of a laminated sheet which is useful for manufacturing the foamed laminated sheet.SOLUTION: The laminated sheet includes at least a foaming agent-containing resin layer and a surface protection layer formed sequentially on a base material. In the method for producing the laminated sheet, (1) the surface protection layer is made of a single layer or a double layers, and at least one layer constituting the surface protection layer contains polyethylene and/or an ethylene copolymer, and (2) a process 1 for forming the foaming agent-containing resin layer on the base material, (3) a process 2 for forming the surface protection layer on the foaming agent-containing resin layer by extrusion film forming, and (4) a process 3 for crosslinking the polyethylene and/or the ethylene copolymer by irradiating the polyethylene and/or the ethylene copolymer with electron beams from the surface protection layer side are included.

Description

  The present invention relates to a laminated sheet and a method for producing a foam laminated sheet.

  In the present specification, the foamed laminated sheet has a foamed resin layer and is useful as foamed wallpaper, various decorative materials, and the like. Moreover, a lamination sheet is a state before foaming of a foaming lamination sheet, and means what is called an unfoamed original fabric.

  Conventionally, as a method for improving the stain resistance and scratch resistance of foamed wallpaper, an ethylene-vinyl alcohol copolymer resin film (Eval film, “Eval” is a trade name) and a polypropylene film prepared on the surface of the foamed wallpaper are prepared. A method of laminating at the same time as embossing is disclosed (Patent Documents 1 and 2).

  However, when a film is prepared in advance and laminated simultaneously with embossing as in Patent Documents 1 and 2, it is necessary to wind up after forming the film, so that no breakage or elongation occurs at that time. Thus, a certain film strength and thickness are required. Moreover, in order to prevent the film from softening and stretching due to heat during embossing, there is a limit to the melting point and softening temperature of the film used.

  Also proposed is a method of forming a surface protective layer by an extrusion laminating method after foaming a foaming agent-containing resin layer formed on a paper substrate. Here, the surface protective layer is formed for the purpose of improving the stain resistance and scratch resistance of the foamed wallpaper. However, since pressure is applied to the foamed resin layer when laminating the surface protective layer after foaming, there is a problem that foam thickness (magnification) is reduced and foam cells are broken.

  Further, it has also been proposed to heat-foam and emboss after a high melting point resin is extrusion laminated to the foaming agent-containing resin layer, but in this case, there is a problem that the embossing property is insufficient. Furthermore, it has also been proposed to extrude and laminate a low-melting point resin to the foaming agent-containing resin layer. In this case, the resin softens during heat foaming or embossing to ensure contamination resistance and scratch resistance. There is a problem that a sufficient surface protective layer cannot be obtained.

  Therefore, it is desired to develop a foamed laminated sheet having improved stain resistance and scratch resistance compared to conventional foamed wallpaper (foamed laminated sheet) and a new method for producing a laminated sheet useful for producing the foamed laminated sheet. ing.

JP 2001-260287 A JP 2009-72967 A

  The main object of the present invention is to provide a foamed laminated sheet with improved contamination resistance and scratch resistance and a new method for producing a laminated sheet useful for producing the foamed laminated sheet.

  As a result of intensive studies to achieve the above object, the present inventor has obtained the above object when a laminated sheet and a foam laminated sheet are produced by combining a surface protective layer containing a specific resin component and a specific process. The present invention has been completed.

That is, this invention relates to the manufacturing method of the following laminated sheet and foaming laminated sheet.
1. A method for producing a laminated sheet in which at least a foaming agent-containing resin layer and a surface protective layer are sequentially formed on a substrate,
(1) The surface protective layer is composed of a single layer or multiple layers, and at least one layer constituting the surface protective layer is a layer containing polyethylene and / or an ethylene copolymer,
(2) Step 1 of forming the foaming agent-containing resin layer on the substrate;
(3) Step 2 of forming the surface protective layer on the foaming agent-containing resin layer by extrusion film formation,
(4) A method for producing a laminated sheet, comprising the step 3 of crosslinking the polyethylene and / or the ethylene copolymer by irradiating an electron beam from the surface protective layer side.
2. The method for producing a laminated sheet according to Item 1, wherein the surface protective layer is a multilayer, and at least the lowest layer is a layer containing the polyethylene and / or ethylene copolymer.
3. Item 3. The method for producing a laminated sheet according to Item 1 or 2, wherein the layer containing polyethylene and / or ethylene copolymer contains at least one of polyethylene and ethylene-methacrylic acid copolymer.
4). Item 4. The method for producing a laminated sheet according to any one of Items 1 to 3, wherein in the step 3, the foaming agent-containing resin layer is also crosslinked by irradiating an electron beam from the surface protective layer side.
5. The manufacturing method of a foaming lamination sheet which has the process 4 which uses the said foaming agent containing resin layer as a foaming resin layer by heating the lamination sheet manufactured by the manufacturing method in any one of said item | item 1-4.
6). The manufacturing method of the foaming lamination sheet of the said claim | item 5 which has the process 5 which embosses from the uppermost surface layer after the said process 4. FIG.

  Hereinafter, the manufacturing method of the lamination sheet of this invention and a foaming lamination sheet is demonstrated.

Method for producing laminated sheet The method for producing a laminated sheet of the present invention is a method for producing a laminated sheet in which at least a foaming agent-containing resin layer and a surface protective layer are sequentially formed on a substrate,
(1) The surface protective layer is composed of a single layer or multiple layers, and at least one layer constituting the surface protective layer is a layer containing polyethylene and / or an ethylene copolymer,
(2) Step 1 of forming the foaming agent-containing resin layer on the substrate;
(3) Step 2 of forming the surface protective layer on the foaming agent-containing resin layer by extrusion film formation,
(4) It has the process 3 which bridge | crosslinks the said polyethylene and / or an ethylene copolymer by irradiating an electron beam from the said surface protective layer side.

  In the method for producing a laminated sheet of the present invention having the above characteristics, at least one layer constituting the surface protective layer is a layer containing polyethylene and / or an ethylene copolymer, and specific steps 1 to 3 are employed. . Therefore, the foamed laminated sheet of the present invention obtained by heating the obtained laminated sheet has good stain resistance and scratch resistance. Moreover, generation | occurrence | production of the fall of the foaming thickness of the foamed resin layer at the time of manufacture which was the subject of the conventional foaming lamination sheet and the tearing of a foaming cell are suppressed.

Process 1
Step 1 forms a foaming agent-containing resin layer on the substrate.

  It does not limit as a base material, A well-known fibrous base material (backing paper) etc. can be utilized.

  Specifically, wallpaper general paper (pulp-based sheet sized with a known sizing agent); flame-retardant paper (pulp-based sheet treated with a flame retardant such as guanidine sulfamate or guanidine phosphate) ); Inorganic paper containing inorganic additives such as aluminum hydroxide and magnesium hydroxide; fine paper; thin paper.

Although the basis weight of the substrate is not critical, preferably about 50 to 300 g / ^{m 2,} about 50 to 120 / ^{m 2} is more preferable.

  The foaming agent-containing resin layer is not limited as long as it contains a resin component and a foaming agent, and the foaming agent-containing resin layer becomes a foamed resin layer by heating described later.

  The resin component of the foaming agent-containing resin layer is not limited, but from the group consisting of polyethylene and an ethylene copolymer having monomers other than ethylene and ethylene (hereinafter abbreviated as “ethylene copolymer”). It is preferable to contain at least one selected.

  Polyethylene and ethylene copolymers are suitable for extrusion film formation in terms of melting point and MFR. Examples of the ethylene copolymer include an ethylene-vinyl acetate copolymer (EVA), an ethylene-methyl methacrylate copolymer (EMMA), an ethylene-ethyl acrylate copolymer (EEA), and an ethylene-methyl acrylate copolymer. Examples thereof include a polymer (EMA), an ethylene- (meth) acrylic acid copolymer (EMAA), and an ethylene-α olefin copolymer. These ethylene copolymers can be used alone or in admixture of two or more.

  In particular, it is preferable to contain any one of an ethylene-vinyl acetate copolymer, an ethylene-methyl methacrylate copolymer, and a mixture of polyethylene and an ethylene-α-olefin copolymer. When the resin component contains a mixture of polyethylene and an ethylene-α-olefin copolymer, the content of the ethylene-α-olefin copolymer is preferably 50% by weight or more.

  When one of ethylene-vinyl acetate copolymer, ethylene-methyl methacrylate copolymer, and a mixture of polyethylene and ethylene-α-olefin copolymer is used in combination with one or more other resins, The content of any one of the resin components is preferably 70% by weight or more, and more preferably 80% by weight or more.

  The MFR of the polyethylene or ethylene copolymer is preferably 9 to 70 g / 10 minutes, and more preferably 9 to 20 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.

  Moreover, 5-30 weight% is preferable as an ethylene copolymer content of monomers other than ethylene, and 9-20 weight% is more preferable. By adopting such a copolymerization ratio, the extrusion film forming property is further enhanced. As a specific example, the ethylene-vinyl acetate copolymer has a vinyl acetate copolymerization ratio (VA amount) of preferably 9 to 25% by weight, more preferably 9 to 20% by weight. The ethylene-methyl methacrylate copolymer has a methyl methacrylate copolymerization ratio (MMA amount) of preferably 5 to 25% by weight, more preferably 5 to 15% by weight.

  As the resin composition for forming the foaming agent-containing resin layer, for example, a resin composition containing the above resin component, foaming agent, inorganic filler, pigment, foaming aid, crosslinking aid and the like can be suitably used. In addition, stabilizers, lubricants and the like can be used as additives.

  The foaming agent can be selected from known foaming agents. For example, azo type such as azodicarbonamide (ADCA) and azobisformamide; organic thermal decomposition type foaming agent such as hydrazide type such as oxybenzenesulfonyl hydrazide (OBSH) and paratoluenesulfonyl hydrazide, microcapsule type foaming agent, Examples include inorganic foaming agents such as baking soda.

  The content of the 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 foaming agent is preferably about 1 to 20 parts by mass with respect to 100 parts by mass of the resin component.

  Examples of the foaming aid include metal oxides such as zinc stearate, zinc oxide, and magnesium oxide and / or fatty acid metal salts. About 0.3-10 mass parts is preferable with respect to 100 mass parts of resin components, and, as for content of these foaming adjuvants, about 1-5 mass parts is more preferable. When these foaming assistants, EMAA, and ADCA foaming agents are used in combination, the foamed resin layer and the base material may be yellowed due to burning or chromophore formation in the foaming process. Therefore, when EMAA and ADCA foaming agent are used in combination, it is preferable to use a carboxylic acid hydrazide compound as a foaming aid as described in JP-A-2009-197219. At this time, it is preferable to use about 0.2-1 mass part of carboxylic acid hydrazide compounds with respect to 1 mass part of ADCA foaming agent.

  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 mass parts is preferable with respect to 100 mass parts of resin components, and, as for content of an inorganic filler, about 20-70 mass parts is more preferable.

  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, ultramarine, bitumen, cobalt blue, chromium oxide, cobalt green, aluminum powder, bronze powder, titanium mica, and zinc sulfide. Examples of organic pigments include 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, indanthrone, halogenated phthalocyanine). About 10-50 mass parts is preferable with respect to 100 mass parts of resin components, and, as for content of a pigment, about 15-30 mass parts is more preferable.

  Although the thickness of a foaming agent containing resin layer is not limited, About 40-100 micrometers is preferable.

  The method for forming the foaming agent-containing resin layer on the substrate is not limited, but it is preferably formed by extrusion film formation (extrusion lamination) with a T-die extruder. In addition, although the cylinder temperature and die temperature at the time of extrusion film formation should just be set suitably according to the kind of resin, generally it is about 100-140 degreeC.

  In the present invention, when the foaming agent-containing resin layer is formed, the foaming agent-containing resin layer may be formed alone, but may have a non-foaming resin layer on one side or both sides thereof.

  For example, the back surface (surface on which the base material is laminated) of the foaming agent-containing resin layer may have a non-foamed resin layer B (adhesive resin layer) for the purpose of improving the adhesive force with the base material.

  The resin component of the non-foamed resin layer B is not particularly limited, but an ethylene-vinyl acetate copolymer (EVA) is preferable. EVA can be a known or commercially available one. In particular, the vinyl acetate component (VA component) is preferably 10 to 46 mass%, more preferably 15 to 41 mass%.

  The thickness of the non-foamed resin layer B is not limited, but is preferably about 5 to 50 μm.

  On the upper surface of the foaming agent-containing resin layer, a non-foamed resin layer A may be provided for the purpose of clarifying the design pattern when forming the design pattern layer or improving the scratch resistance of the foamed resin layer.

  Examples of the resin component of the non-foamed resin layer A include polyolefin resins, methacrylic resins, thermoplastic polyester resins, polyvinyl alcohol resins, fluorine resins, and the like, among which polyolefin resins are preferable.

  Examples of polyolefin resins include polyethylene, polypropylene, polybutene, polybutadiene, polyisoprene, and other resins, copolymers of α-olefins having 4 or more carbon atoms (linear low density polyethylene), and ethylene-acrylic acid copolymers. Resin, ethylene-methyl acrylate copolymer resin, ethylene-ethyl acrylate copolymer resin, ethylene (meth) acrylic acid copolymer resin such as ethylene-methacrylic acid copolymer resin, ethylene-vinyl acetate copolymer Examples thereof include at least one of coalesced (EVA), ethylene-vinyl acetate copolymer resin saponified product, and ionomer.

  The thickness of the non-foamed resin layer A is not limited, but is preferably about 5 to 50 μm.

  In this invention, the aspect in which the said non-foamed resin layer B, the foaming agent containing resin layer, and the non-foamed resin layer A were formed in order is preferable.

  When the foaming agent-containing resin layer has a non-foamed resin layer on one side or both sides, simultaneous extrusion film formation by a T-die extruder is suitable. For example, in the case of having non-foamed resin layers on both sides, a multi-manifold type T-die capable of simultaneously forming three layers by simultaneously extruding molten resins corresponding to the three layers can be used.

  In addition, when an inorganic filler is contained in the resin composition forming the foaming agent-containing resin layer and the foaming agent-containing resin layer is formed by extrusion film formation, an extrusion port (so-called die) of the extruder is used. Inorganic filler residues (so-called eyes and eyes) are easily generated, and this tends to be a foreign matter on the surface of the foaming agent-containing resin layer. Therefore, when an inorganic filler is contained in the resin composition forming the foaming agent-containing resin layer, it is preferable to form a three-layer coextrusion film as described above. That is, it is possible to suppress the occurrence of the above-mentioned corners by co-extrusion film formation in a mode in which the foaming agent-containing resin layer is sandwiched between non-foamed resin layers.

  In the present invention, in step 1, a pattern layer may be further formed on the foaming agent-containing resin layer (or on the non-foamed resin layer A).

  The design pattern layer imparts design properties to the resin laminate. 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. Examples of printing methods include gravure printing, flexographic printing, silk screen printing, offset printing, and the like. As the printing ink, a printing ink containing a colorant, a binder resin, and a solvent 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 can be set according to the type of the base sheet. For example, acrylic resin, styrene resin, polyester resin, urethane resin, chlorinated polyolefin resin, vinyl chloride-vinyl acetate copolymer resin, polyvinyl butyral resin, alkyd resin, petroleum resin, ketone resin, epoxy Resin, melamine resin, fluorine resin, silicone resin, fiber derivative, rubber resin 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. These solvents (or dispersion media) can be used alone or in the form of a mixture.

  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.

Process 2
In step 2, the surface protective layer is formed by extrusion film formation on the foaming agent-containing resin layer (on the non-foamed resin layer A or the pattern layer if formed).

  In the present invention, the surface protective layer is composed of a single layer or multiple layers, and at least one of the surface protective layers is a layer containing polyethylene and / or an ethylene copolymer.

  Moreover, in this invention, when a surface protective layer is a multilayer, it is preferable that at least the lowest layer (foaming agent containing resin layer side) is a layer containing polyethylene and / or an ethylene copolymer. Since the melt tension of the resin layer is improved by placing a layer containing polyethylene or ethylene copolymer in the lowermost layer and crosslinking the electron beam, the permeation of gas generated from the foamed layer during foaming is efficiently suppressed. be able to. Therefore, if a layer containing polyethylene or an ethylene copolymer is disposed in the lowermost layer, even if a resin (polypropylene or the like) having a relatively low melt tension is disposed in the upper layer, the contamination resistance of the surface protective layer itself and Scratch resistance can be maintained.

  Polyethylene and / or ethylene copolymer includes α-olefin copolymer having 4 or more carbon atoms (linear low density polyethylene), ethylene-acrylic acid copolymer resin, ethylene-methyl acrylate copolymer resin, ethylene -Ethylene (meth) acrylic acid copolymer resin such as ethyl acrylate copolymer resin, ethylene-methacrylic acid copolymer resin, ethylene-vinyl acetate copolymer (EVA), ethylene-vinyl acetate copolymer resin Examples thereof include saponified products and ionomers. In the present invention, it is preferable to contain at least one of polyethylene (PE) and ethylene-methacrylic acid copolymer (EMAA).

The polyethylene, for example, density 0.942 g / cm ³ or more high-density polyethylene (HDPE) and density 0.93 g / cm ³ or more ~0.942g / cm ³ less than the medium density polyethylene (MDPE), density 0.91g Low density polyethylene (LDPE) of / cm ³ or more and less than 0.93 g / cm ³ . Moreover, you may use the ultra-low density polyethylene (LLDPE) whose density is the range of 0.85-0.91 g / cm < ³ >. Among these polyethylenes, it is preferable to use polyethylene having a low density because curling of the foamed laminated sheet can be suppressed.

  Moreover, you may use the medium density polyethylene prepared by mixing these high density polyethylene and low density polyethylene. In this case, the mixing ratio of the high-density polyethylene and the low-density polyethylene is not limited, but is preferably high-density polyethylene: low-density polyethylene = 0-7: 3-10 by mass ratio.

  As the polyethylene, not only an ethylene homopolymer but also a polyethylene-modified resin can be used. Examples of the polyethylene-modified resin include maleic anhydride-modified polyethylene and other acid-modified resins.

  In the case where the surface protective layer is a multilayer, when a resin layer other than a layer containing polyethylene and / or ethylene copolymer is included, polyolefin resin other than polyethylene and / or ethylene copolymer as a resin component, methacrylic resin , Polyvinyl alcohol resin, fluororesin and the like. Among them, polyolefin resins other than polyethylene and / or ethylene copolymers are preferable, and examples of such polyolefin resins include single resins such as polypropylene, polybutene, polybutadiene, and polyisoprene.

  Although the thickness of a surface protective layer is not limited, about 3-25 micrometers is preferable, More preferably, it is 5-20. Moreover, when the surface protective layer is a multilayer, the thickness of each layer is preferably about 5 to 15 μm.

  When the surface protective layer is formed by extrusion film formation, extrusion film formation by a T-die extruder is suitable particularly when the surface protective layer is a multilayer. For example, in the case of two layers, a multi-manifold type T die that can simultaneously form two layers by simultaneously extruding molten resin corresponding to the two layers can be used.

Process 3
Step 3 is the foam lamination obtained by improving the heat resistance of the layer containing polyethylene and / or ethylene copolymer in the surface protective layer by irradiating an electron beam from the surface protective layer side. Excellent stain resistance and scratch resistance of the sheet can be obtained.

  The energy of the electron beam is preferably about 150 to 250 kV, more preferably about 175 to 200 kV. The irradiation amount is preferably about 10 to 100 kGy, and more preferably about 10 to 50 kGy. A known electron beam irradiation apparatus can be used as the electron beam source. The effect of improving heat resistance is obtained by such electron beam irradiation.

  In the present invention, in step 3, the foaming agent-containing resin layer may also be crosslinked. By crosslinking the foaming agent-containing resin layer, the surface strength, foaming characteristics, etc. of the foamed resin layer can be adjusted. Here, when only the surface protective layer is cross-linked, it is not necessary to cross-link the lower foaming agent-containing resin layer, so that it is not necessary to deeply penetrate the electron beam, and the acceleration voltage can be lowered.

  The laminated sheet of this invention is obtained by passing through the above processes 1-3.

Method for Producing Foamed Laminated Sheet The method for producing a foamed laminated sheet according to the present invention includes a step 4 in which a foaming agent-containing resin layer is formed as a foamed resin layer by heating the laminated sheet in addition to the above steps 1 to 3. It becomes a manufacturing method of a lamination sheet.

  The heating conditions are not limited as long as the foaming agent-containing resin layer becomes a foamed resin layer by decomposition of the foaming agent. The heating temperature is preferably about 210 to 240 ° C., and the heating time is preferably about 20 to 80 seconds. When heating, a known heating furnace or gear oven can be used.

  The thickness of the foamed resin layer after foaming is preferably about 300 to 700 μm.

  Moreover, the manufacturing method of the foaming lamination sheet of this invention may have the process 5 which embosses from the uppermost surface layer.

  Embossing can be performed by known means such as an embossed plate. Specifically, a desired embossed pattern can be formed by pressing the embossed plate after heat-softening the surface resin layer. 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.

  The foamed laminated sheet of the present invention is obtained through the above steps 4-5.

  In the method for producing a laminated sheet of the present invention, at least one layer constituting the surface protective layer is a layer containing polyethylene and / or an ethylene copolymer, and specific steps 1 to 3 are employed. Therefore, the foamed laminated sheet of the present invention obtained by heating the obtained laminated sheet has good stain resistance and scratch resistance. Moreover, generation | occurrence | production of the fall of the foaming thickness of the foamed resin layer at the time of manufacture which was the subject of the conventional foaming lamination sheet and the tearing of a foaming cell are suppressed.

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

Example 1
Extrusion film formation using a three-type three-layer multi-manifold T-die extruder so that the thickness is 8 μm / 60 μm / 8 μm in the order of non-foamed resin layer A / foaming agent-containing resin layer / non-foamed resin layer B (adhesive resin layer) did. The extrusion conditions were such that the cylinder temperature and die temperature of each layer were all 120 ° C. Subsequently, a backing paper “NI-65A, made by Nippon Paper Industries” with a surface temperature of 120 ° C. was laminated on the surface of the non-foamed resin layer B through a laminating roll.

  In the above, “Nucleel N1560 (Mitsui / DuPont Polychemical)” was used as a raw material for the non-foamed resin layer A. Moreover, the raw material of the following Table 1 was used as a raw material of a foaming agent containing resin layer. As a raw material of the non-foamed resin layer B, “Evaflex EV150 (Mitsui / DuPont Polychemical)” was used.

  Next, a corona discharge treatment was performed on the non-foamed resin layer A. Furthermore, a texture pattern was printed using a water-based ink “Hydric, manufactured by Dainichi Seika Kogyo” as a pattern print by a gravure printing machine. Thereafter, an aqueous heat sealer “HT-600W (K) Hydrick (manufactured by Dainichi Seika Kogyo)” was coated.

  Subsequently, using a two-type two-layer multi-manifold T-die extruder, the non-foamed resin layer was co-extruded to form a surface protective layer (upper layer) / surface protective layer (lower layer) having a thickness of 7 μm / 3 μm. Laminated to A. Extrusion conditions were a temperature of 250 ° C. for both the cylinder and die of the upper and lower surface resin layers.

  As a raw material of the surface protective layer (upper layer), low density polyethylene (LDPE) (Novatech LC600A, manufactured by Nippon Polyethylene) (MFR = 7) was used. As a raw material of the surface protective layer (lower layer), ethylene- (meth) acrylic acid copolymer modified resin (EMAA) (AN4228C, manufactured by Mitsui / DuPont Polychemical) was used.

  Subsequently, the laminated sheet was obtained by bridge | crosslinking a foaming agent containing resin layer and a surface protective layer by irradiating an electron beam (irradiation conditions: 195 kV, 30 kGy) from the surface protective layer.

  Next, while the laminated sheet is heated in an oven (220 ° C., 35 seconds), the foaming agent-containing resin layer is foamed so that the total thickness of the laminated sheet becomes 580 μm, and then embossed with a texture to perform foaming. A laminated sheet was obtained.

Example 2
A foamed laminated sheet was produced in the same manner as in Example 1 except that high-density polyethylene (HDPE) “Novatech HF560 (manufactured by Nippon Polyethylene): MFR = 7” was used for the surface resin layer (upper layer).

Example 3
A foamed laminated sheet was prepared in the same manner as in Example 1 except that medium density polyethylene (MDPE) “Novatech HC170 (manufactured by Nippon Polyethylene): MFR = 10” was used for the surface resin layer (upper layer).

Example 4
Polypropylene (PP) “NOVATEC FL03H (manufactured by Nippon Polypropylene): MFR = 20” is used for the surface resin layer (upper layer), and polyethylene modified (PE modified) “Modic M545 (manufactured by Mitsubishi Chemical) for the surface resin layer (lower layer): A foamed laminated sheet was produced in the same manner as in Example 1 except that “MFR = 6” was used.

Example 5
Medium density polyethylene (MDPE) “Novatech HC170 (manufactured by Nippon Polyethylene): MFR = 10” is used for the surface resin layer (upper layer), and polyethylene modified product (PE modified) “Modic M545 (Mitsubishi Chemical) is used for the surface resin layer (lower layer). ): MFR = 6 ”was used, and a foamed laminated sheet was produced in the same manner as in Example 1.

Example 6
A foamed laminated sheet was produced in the same manner as in Example 1 except that the surface protective layer was a single layer (10 μm) of low density polyethylene (LDPE) “Novatech LC600A (manufactured by Nippon Polyethylene): MFR = 7”.

Example 7
A foamed laminated sheet was prepared in the same manner as in Example 1 except that polypropylene (PP) “Novatech FL03H (manufactured by Nippon Polypropylene): MFR = 20” was used for the surface resin layer (upper layer).

Example 8
A foamed laminated sheet was produced in the same manner as in Example 1 except that polypropylene (PP) “Wintech WSX02 (manufactured by Nippon Polypropylene): MFR = 25” was used for the surface resin layer (upper layer).

Comparative Example 1
A foamed laminated sheet was produced in the same manner as in Example 1 except that the foaming agent-containing resin layer was foamed without irradiating the surface resin layer with an electron beam.

Comparative Example 2
A foamed laminated sheet was produced in the same manner as in Example 3 except that the foaming agent-containing resin layer was foamed without irradiating the surface resin layer with an electron beam.

Comparative Example 3
A foamed laminated sheet was produced in the same manner as in Example 7 except that the foaming agent-containing resin layer was foamed without irradiating the surface resin layer with an electron beam.

Comparative Example 4
A foamed laminated sheet was produced in the same manner as in Example 8 except that the foaming agent-containing resin layer was foamed without irradiating the surface resin layer with an electron beam.

Comparative Example 5
A foamed laminated sheet was produced in the same manner as in Example 1 except that the surface resin layer was not provided.

Comparative Example 6
A foamed laminate sheet was produced in the same manner as in Example 1 except that the foaming agent-containing resin layer was irradiated with an electron beam and then the surface protective layer was not irradiated with an electron beam.

Comparative Example 7
A foamed laminated sheet was produced in the same manner as in Example 1 except that the surface protective layer was a single layer of polypropylene (PP) “NOVATEC FL03H (made by Nippon Polypropylene): MFR = 20”.

  The characteristics of the foamed laminated sheets produced in the examples and comparative examples were evaluated.

Test example 1 (surface condition)
The cross section of each foamed laminated sheet was observed with an optical microscope.

  The evaluation criteria are as follows.

  Good 1: The surface protective layer is not depressed (not partially thinned).

  Good 2: The surface protective layer is depressed and partially thinned (the lower adjacent layer is not exposed).

  Defect: The surface protective layer is depressed and the adjacent layer below is exposed.

Test example 2 (contamination resistance)
<1> SV method compliant: After leaving for 24 hours in a red crayon, contaminants were removed with a neutral detergent.

  <2> After the wall surface of the wallpaper was contaminated with oily black magic, it was allowed to stand for 24 hours, and the contaminants were removed using ethanol.

After the tests <1> and <2>, the evaluation was performed as follows.
○: No red crayon and oily magic remaining.
Δ: Slight remaining of red crayon and / or oily magic.
X: Red crayon and oily magic remain.

  The results of Examples are shown in Table 2, and the results of Comparative Examples are shown in Table 3.

Claims (6)

A method for producing a laminated sheet in which at least a foaming agent-containing resin layer and a surface protective layer are sequentially formed on a substrate,
(1) The surface protective layer is composed of a single layer or multiple layers, and at least one layer constituting the surface protective layer is a layer containing polyethylene and / or an ethylene copolymer,
(2) Step 1 of forming the foaming agent-containing resin layer on the substrate;
(3) Step 2 of forming the surface protective layer on the foaming agent-containing resin layer by extrusion film formation,
(4) A method for producing a laminated sheet, comprising the step 3 of crosslinking the polyethylene and / or the ethylene copolymer by irradiating an electron beam from the surface protective layer side.   The method for producing a laminated sheet according to claim 1, wherein the surface protective layer is a multilayer, and at least the lowermost layer is a layer containing the polyethylene and / or ethylene copolymer.   The method for producing a laminated sheet according to claim 1 or 2, wherein the layer containing polyethylene and / or ethylene copolymer contains at least one of polyethylene and ethylene-methacrylic acid copolymer.   The manufacturing method of the lamination sheet in any one of Claims 1-3 which also bridge | crosslinks the said foaming agent containing resin layer in the said process 3 by irradiating an electron beam from the said surface protective layer side.   The manufacturing method of a foaming lamination sheet which has the process 4 which uses the said foaming agent containing resin layer as a foaming resin layer by heating the lamination sheet manufactured by the manufacturing method in any one of Claims 1-4.   The manufacturing method of the foaming lamination sheet of Claim 5 which has the process 5 which embosses from the uppermost surface layer after the said process 4. FIG.