JP6645010B2 - Resin composition, resin sheet, laminated sheet and foamed wallpaper - Google Patents

Description

  The present invention relates to a resin composition, a resin sheet, a laminated sheet, and a foamed wallpaper. More specifically, the present invention relates to a foamed wallpaper that can be used for wall decoration of buildings such as a detached house, an apartment house, a store, and an office building, and a resin composition, a resin sheet, and a laminated sheet used therefor.

  BACKGROUND ART As a wallpaper used for a wall decoration of a building or the like, a vinyl chloride wallpaper in which a resin layer of a vinyl chloride resin is provided on a paper base material is widely used. In recent years, non-chlorinated thermoplastic resins such as ethylene-vinyl acetate copolymer have been used in consideration of the environment (for example, see Patent Documents 1 and 2 below).

  As a method for producing these foamed wallpapers, a resin composition containing a foaming agent is melt-extruded and laminated on a base material, or is separately sheeted by a T-die extrusion method, and then dried or thermally laminated. After laminating the base material to obtain a laminated sheet with a resin sheet provided on the base material, the resin sheet with the printed surface is heated as necessary to decompose and foam the foaming agent. There is a way to make it happen.

  In such a foamed wallpaper to which a pyrolytic foaming agent is added, it is known that a fatty acid metal salt is used as a foaming aid for the purpose of accelerating the decomposition of the foaming agent and adjusting the decomposition temperature. For example, Patent Document 3 discloses that zinc stearate and zinc octylate are used as foaming assistants.

JP-A-6-47875 JP 2001-347611 A JP 2010-228416 A

  However, the resin sheet for foamed wallpaper in which the above-mentioned fatty acid metal salt is blended so as to obtain a high foaming ratio, when a product to be printed on the surface is used, the adhesiveness of the ink, the transferability of the pattern and the like. The printability was sometimes reduced.

  The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a resin composition, a resin sheet, a laminated sheet, and a foamed wallpaper having good foamability and sufficient printability.

  In order to solve the above problems, the present invention is a resin composition for forming the foamed resin layer of foamed wallpaper comprising a base material and a foamed resin layer provided on the base material, A resin composition comprising a filler, a foaming agent, a foaming aid, and a resin component, wherein the foaming aid comprises a complex of one or more of fatty acid zinc and a fatty acid metal salt other than fatty acid zinc. provide.

  According to the resin composition of the present invention, it is possible to form a resin sheet having good foamability and sufficient printability. The present inventors presume the reason why such an effect is obtained as follows. First, as a factor that the printability of the resin sheet containing the conventional fatty acid metal salt is reduced, the surface activity of the fatty acid metal salt is very strong, and the bleed-out to the surface on which printing is performed or the printing interface after printing. It is conceivable that the fatty acid metal salt reduces the surface wettability and the ink affinity, and reduces the adhesion of the ink. On the other hand, in the present invention, by using a complex of fatty acid zinc and one or more kinds of fatty acid metal salts other than fatty acid zinc, the effect of improving the foaming property is sufficiently obtained, and the foaming aid is reduced by the reduction of the melting point due to the complexation. The present inventors believe that the bleed-out can be reduced by improving the compatibility between the agent and the resin component.

  Further, according to the resin composition of the present invention, for example, sufficient printability can be ensured without requiring a measure such as providing a non-foamed layer on the surface of the laminated sheet to block bleed out of the foaming aid. Therefore, it is possible to form a resin sheet having both sufficient printability and good foamability with a simpler sheet structure.

  The molar ratio of zinc to a metal other than zinc in the composite can be from 3: 1 to 1: 3. By using such a composite, both the effect as a foaming aid and the printability can be balanced.

  The complex is preferably a complex of zinc fatty acid and one or more selected from the group consisting of fatty acid magnesium, fatty acid calcium, fatty acid strontium, fatty acid barium, and fatty acid radium. Since these fatty acid metal salts have a high effect as an internal lubricant, the dispersibility of the composite can be further improved. By using such a composite, both the effect as a foaming aid and the printability can be achieved at a higher level.

The resin component preferably contains at least a density of 0.91 g / cm ³ or more 0.94 g / cm ³ or less of low density polyethylene. By using such a resin, the flexibility of the resin can be improved, and it becomes easy to realize a foamed wallpaper having a foamed resin layer in a good foamed state and excellent in workability.

The resin component, in addition to the low density polyethylene described above, may further include an ultra low density polyethylene density of less than 0.88 g / cm ³ or more 0.91 g / cm ^3. By using such a resin, it is possible to further improve the flexibility of the resin, to have a foamed resin layer in a good foamed state, and to more easily realize a foamed wallpaper having excellent workability. .

  The content of the composite is preferably 10 to 150 parts by mass with respect to 100 parts by mass of the foaming agent. When the content of the composite is within the above range, it is possible to form a resin sheet that can achieve both good foamability and sufficient printability at a higher level.

  The present invention also provides a resin sheet obtained by extruding the resin composition according to the present invention into a film. The resin sheet of the present invention can have good foamability and sufficient printability.

  The resin sheet according to the present invention may be subjected to a crosslinking treatment. Thereby, outgassing during foaming can be suppressed, and a foamed resin layer that is uniform and has less outgassing from the surface can be obtained.

  The present invention also provides a laminated sheet comprising a base material and the resin sheet according to the present invention provided on the base material.

  The present invention is also a foamed wallpaper comprising a base material and a foamed wallpaper provided on the base material, and is obtained by foaming a foaming agent contained in the resin sheet in the laminated sheet according to the present invention. Provide foamed wallpaper.

  According to the present invention, it is possible to provide a resin composition, a resin sheet, a laminated sheet, and foamed wallpaper having good foamability and sufficient printability.

[Resin composition]
The resin composition according to the present embodiment is a resin composition for forming a foamed resin layer of foamed wallpaper including a base material and a foamed resin layer provided on the base material, and a filler. , A foaming agent, a foaming assistant, and a resin component.

  Examples of the filler in the present embodiment include an inorganic filler and an organic filler. Examples of the inorganic filler include calcium carbonate, titanium dioxide and the like, and these can be used alone or in combination of two or more. Examples of the organic filler include melamine cyanurate, polytetrafluoroethylene (PTFE), wood flour, cellulose and derivatives thereof, and these may be used alone or in combination of two or more. it can.

  The content of the filler is not particularly limited, but the total amount is preferably 10 to 60% by mass based on the total amount of the resin composition. Reasons for adding the filler include ensuring the concealing property of the foamed wallpaper, reducing the calorie burned per unit area, and reducing the production cost by increasing the bulk. However, the filler (particularly, the inorganic filler) is contained. When the amount is 20 to 40% by mass based on the total amount of the resin composition, it is possible to produce a foamed wallpaper having a low burning calorie and a low production cost while securing good concealing properties as a foamed wallpaper.

  As the foaming agent according to the present embodiment, for example, a pyrolytic foaming agent can be used. Examples of the thermal decomposition type foaming agent include azo foaming agents such as azodicarbonamide (ADCA), azobutyronitrile and diazoaminobenzene, hydrazide foaming agents such as p-toluenesulfonyl hydrazide, and N, N'-di. Nitroso-based blowing agents such as nitrosopentamethylenetetramine and the like. Among these, ADCA, which has low toxicity, easily controls the foaming start temperature, and has a wide application range, is preferable. These can be used alone or in combination of two or more.

  The content of the foaming agent is not particularly limited, but the total amount is preferably 1 to 20% by mass based on the total amount of the resin composition. When the content of the foaming agent is in the above range, it is possible to obtain a foamed resin layer in which gas escape from the surface due to generation of excessive gas is suppressed.

  The foaming aid according to the present embodiment includes a complex of zinc fatty acid and one or more fatty acid metal salts other than zinc zinc fatty acid. The complex can be obtained by using a mixture of zinc oxide and one or more metal oxides other than zinc oxide in a desired ratio and neutralizing with a fatty acid. The fatty acid used as the raw material for synthesis is not particularly limited, and the constituent hydrocarbon group may be straight-chain or branched. The hydrocarbon group may be saturated or unsaturated, and preferably has 6 to 30 carbon atoms. However, when the number of carbon atoms decreases, the melting point of metal soap (fatty acid metal salt) decreases. The number of carbon atoms is more preferably from 10 to 24, from the viewpoint that it becomes liquid and handling becomes difficult, and that if the carbon chain is too long, the melting point becomes too high and the dispersibility at the molding temperature decreases. Examples of the fatty acid having such a hydrocarbon group include, for example, saturated fatty acids such as caprylic acid, stearic acid, lauric acid, and behenic acid; dicarboxylic acids such as sebacic acid and azelaic acid; oleic acid, linoleic acid, and undecylenic acid And the like.

  As the fatty acid metal salt other than the fatty acid zinc, a metal salt having a smaller ionic radius than zinc may be used. By using a fatty acid metal salt having a metal whose ionic radius is smaller than that of zinc, the melting point of the composite can be made lower than the melting points of the fatty acid zinc and the fatty acid metal salt. For example, when calcium stearate and zinc stearate are used in a molar ratio of 1: 1. In the case of a mere mixture, the melting point peak of zinc stearate at 115 ° C. to 123 ° C. and the melting point peak of calcium stearate at 148 ° C. to 155 ° C. Is observed, but in the case of the composite of the present embodiment, a single melting point peak is observed at 95 ° C to 102 ° C. The melting point is a value measured by a thermal analyzer capable of performing differential thermal analysis (DTA). When the melting point is measured by the thermal analyzer, the temperature at which the peak of the heat of fusion starts to rise (melting start temperature) to the temperature at which the peak returns to the baseline (melting end temperature) is recorded as the melting point.

  In the composite according to the present embodiment, the melting point obtained by the above-described measurement method is preferably close to the melting point of the resin serving as the main component among the resin components described below. For example, when the resin component as the main component is low-density polyethylene, the melting point of the composite is preferably in the range of 90 to 110 ° C. When the resin component as the main component is an ethylene-vinyl acetate copolymer, the melting point of the composite is preferably in the range of 79 to 90 ° C. Note that the lower limit of the numerical range of the melting point is a value that the above-mentioned melting end temperature can take, and the upper limit is a value that the above-mentioned melting start temperature can take.

  As described above, by lowering the melting point of the foaming aid, compatibility with the resin component can be improved, thereby effectively reducing bleed-out, and further improving foamability and printability at a higher level. Can be compatible. In particular, when combined with an ethylene homopolymer or a copolymer of ethylene and another olefin as the resin component, the effect of improving the ink-philicity due to a reduction in bleed-out due to the large surface energy of the base resin is greater. It is possible to obtain a resin sheet or a laminated sheet for foamed wallpaper that is exhibited and has good printability.

  The fatty acid metal salt other than the fatty acid zinc is preferably at least one selected from the group consisting of fatty acid magnesium, fatty acid calcium, fatty acid strontium, fatty acid barium, and fatty acid radium. Since these fatty acid metal salts have a high effect as an internal lubricant, the dispersibility of the composite can be further improved. Above all, from the viewpoints of safety and cost, it is more preferable that at least one selected from fatty acid magnesium and fatty acid calcium is used.

  The molar ratio of zinc to metals other than zinc in the composite according to this embodiment is preferably 3: 1 to 1: 3, more preferably 2: 1 to 1: 2, and more preferably 1: 1. It is even more preferred. When the molar ratio of zinc to a metal other than zinc is within the above range, the effect as a foaming aid and sufficient printability can be obtained in a well-balanced manner.

  The content of the composite according to the present embodiment is preferably in the range of 1 to 10 parts by mass, more preferably in the range of 1 to 6 parts by mass with respect to 100 parts by mass of the resin component. . When the content is in the range of 1 to 10 parts by mass with respect to 100 parts by mass of the resin component, a resin sheet having better printability can be formed. When the content is 1 part by mass or more, the effect as a foaming aid of the composite is sufficiently obtained, and the decomposition efficiency of the foaming agent tends to be further improved. It is hardly affected by the composite existing on the surface of the resin sheet thus prepared, and the printability can be kept good.

  The content of the composite according to the present embodiment is preferably 10 to 150 parts by mass, more preferably 20 to 100 parts by mass, and more preferably 20 to 50 parts by mass with respect to 100 parts by mass of the foaming agent. Is more preferable. When the content is in the range of 10 to 150 parts by mass with respect to 100 parts by mass of the foaming agent, a resin sheet having better printability and expansion ratio can be formed.

  The foaming assistant of the present embodiment may include a foaming assistant other than the above-described composite as long as the effect of the present invention is not impaired. Examples of such foaming aids include aliphatic fatty acids such as stearic acid and lauric acid, fatty acid amides such as stearic acid amide and oleic acid amide, and fatty acid metal salts such as zinc stearate, calcium laurate and zinc octylate. In addition to the urea system, urea system, zinc chloride, zinc oxide and the like can be mentioned.

  The content of the composite with respect to the foaming aid is preferably 25 to 100% by mass, more preferably 50 to 100% by mass, based on the total amount of the foaming aid. When the content is in the range of 25 to 100% by mass based on the total amount of the foaming aid, a resin sheet having better printability can be formed.

  The resin component according to the present embodiment preferably contains a non-chlorine thermoplastic resin from the viewpoint of preventing generation of toxic gas such as dioxin during combustion. Examples of the chlorine-free thermoplastic resin include ethylene homopolymer, copolymers of ethylene and other olefins, polyolefin resins (polypropylene, polybutene, polymethylpentene, etc.), and styrene resins (polystyrene, acrylonitrile / styrene resin) , Acrylonitrile, butadiene, styrene resin, etc.), ethylene copolymer (ethylene-vinyl acetate copolymer, ethylene-methyl methacrylate copolymer, ethylene-acrylic acid copolymer, ethylene-ethyl acrylate copolymer, ethylene-methyl acrylate copolymer) Polymer, ethylene-methacrylic acid copolymer, etc.). These can be used alone or in combination of two or more.

  Among them, the resin component according to the present embodiment is preferably non-polar. By using such a non-polar resin, the thickening effect when the above-mentioned filler is added can be minimized, and high-quality wallpaper can be stably produced. Further, such a nonpolar resin preferably contains an ethylene homopolymer or a copolymer of ethylene and another olefin. By using an ethylene homopolymer or a copolymer of ethylene and another olefin, the surface energy of the base resin is large, so that the effect of improving the ink affinity due to the reduction of bleed-out is exerted more.

  Examples of the ethylene homopolymer include low-density polyethylene synthesized by a high-pressure method and high-density polyethylene containing no comonomer synthesized by a medium-low pressure method. Among them, low density polyethylene is preferred.

Low density polyethylene, for example, those having a density in the range of 0.91 g / cm ³ or more 0.94 g / cm ³ or less. The density of low-density polyethylene is preferably not 0.91 g / cm ³ or more 0.93 g / cm ³ or less, more preferably 0.92 g / cm ³ or more 0.93 g / cm ³ or less. The molecular weight, melting point, melt flow rate (MFR) and the like of the low-density polyethylene are not particularly limited. When the melting point is 140 ° C. or lower, it is not necessary to melt the resin at a higher temperature when melting and molding, and there is little possibility that the foaming agent is decomposed during molding. On the other hand, when the melting point is 50 ° C. or higher, sufficient heat durability in practical use can be obtained. The MFR is preferably from 3 to 150, more preferably from 4 to 100. When the MFR is 3 or more, shear heat generated during molding can be suppressed, the processing temperature can be easily controlled, and there is little possibility that the foaming agent is decomposed during molding. On the other hand, if the MFR is 150 or less, the mechanical strength of the manufactured foamed wallpaper is maintained, and the workability and the durability are excellent.

  As the low-density polyethylene, for example, commercially available products such as Novatec LD LC802A, Novatec LD LC604 (all manufactured by Nippon Polyethylene), Ube Polyethylene J2516 (Ube Maruzen Polyethylene) and the like can be used.

  Copolymers of ethylene and other olefins include, for example, linear low-density polyethylene, ultra-low-density polyethylene, high-density polyethylene obtained by copolymerization with a comonomer, and the like. Alternatively, two or more kinds can be used in combination. Among them, ultra-low density polyethylene is preferable.

The ultra low density polyethylene, for example, those in the range of less than the density 0.88 g / cm ³ or more 0.91 g / cm ^3. The density of the ultra-low density polyethylene is preferably 0.88 g / cm ³ or more and 0.90 g / cm ³ or less, and more preferably 0.89 g / cm ³ or more and 0.90 g / cm ³ or less. The molecular weight, melting point, MFR and the like of the ultra-low density polyethylene are not particularly limited, but the melting point is preferably from 50 to 140 ° C, more preferably from 60 to 110 ° C. When the melting point is 140 ° C. or lower, it is not necessary to melt the resin at a higher temperature when melting and molding, and there is little possibility that the foaming agent is decomposed during molding. On the other hand, when the melting point is 50 ° C. or higher, sufficient heat durability in practical use can be obtained. The MFR is preferably from 3 to 150, more preferably from 4 to 100. When the MFR is 3 or more, shear heat generated during molding can be suppressed, processing temperature can be easily controlled, and there is little possibility that the foaming agent is decomposed during molding. On the other hand, if the MFR is 150 or less, the mechanical strength of the manufactured foamed wallpaper is maintained, and the workability and the durability are excellent.

  Examples of ultra-low-density polyethylene include Toughmer DF140, DF940, and DF7350 (all manufactured by Mitsui Chemicals), Kernel KJ-640T (made by Nippon Polyethylene), Exelen FX CX5508 (made by Sumitomo Chemical), Engage 8400/8407 (Dow Chemical) And Evolu P SP90100 (manufactured by Prime Polymer).

  The content of the resin component is preferably 20 to 80% by mass, more preferably 40 to 75% by mass, and more preferably 50 to 70% by mass, based on the total amount of the resin composition. It is even more preferred. In this case, the resin component may be cross-linked.

  Further, the resin composition according to the present embodiment may be colored by adding a pigment or the like as necessary. Coloring by adding a pigment may be transparent, translucent, or opaque. Examples of the pigment include inorganic pigments such as iron oxide and carbon black, and organic pigments such as aniline black and phthalocyanine blue.

  The amount of the pigment to be added is preferably 5 to 50% by mass, more preferably 10 to 30% by mass, based on the total amount of the resin composition.

  In addition, known additives such as a flame retardant, a cell conditioner, a stabilizer, and a lubricant can be used in the resin composition as needed.

  Examples of the flame retardant include metal oxide flame retardants such as magnesium hydroxide and aluminum hydroxide, phosphorus flame retardants such as phosphate esters, and bromine flame retardants such as tetrabromobisphenol A.

  Examples of the cell conditioner include an acrylate resin and a methacrylate resin.

  Examples of the stabilizer include radical scavengers such as phenol / amine antioxidants, hindered amine light stabilizers, peroxide decomposers such as phosphorus and sulfur, benzotriazole, hydroxyphenyltriazine, and benzophenone. UV absorbers and the like.

  Examples of the lubricant include fatty acid-based lubricants such as stearic acid and lauric acid, fatty acid amide-based lubricants such as stearic acid amide and oleic amide, and fatty acid metal salt-based lubricants such as zinc stearate, calcium laurate, and zinc octylate. Can be

[Resin sheet]
The resin sheet according to the embodiment is formed from the resin composition according to the embodiment. The resin sheet according to the present embodiment can be obtained, for example, by extruding the resin composition according to the present embodiment into a film.

  Examples of the extrusion film forming method include extrusion molding such as T-die extrusion, T-die extrusion simultaneous lamination, T-die extrusion tandem lamination, circular die extrusion, and circular die inflation extrusion.

  In addition to extrusion molding, the resin sheet according to the present embodiment is also manufactured by a known molding method such as injection molding, press molding, blow molding, calendar molding, coating molding, cast molding, dipping molding, vacuum molding, or transfer molding. be able to.

  After melting, kneading and dispersing each component with an extruder, the resin composition may be appropriately pelletized. The extruder may be a single-screw extruder or a twin-screw extruder, but a twin-screw extruder is desirable in consideration of the influence on productivity and quality.

  Extrusion film forming conditions include an extrusion temperature of 100 to 160 ° C. and an extrusion pressure of 2 to 50 MPa. The extrusion temperature is preferably from 110 to 150 ° C, more preferably from 120 to 140 ° C, from the viewpoint of suppressing the decomposition of the foaming agent component and increasing the melting point of the polyethylene component or more. In addition, from the viewpoint of extrusion stability, the extrusion pressure is preferably from 3 to 40 MPa, and more preferably from 3 to 30 MPa.

  The thickness of the resin sheet can be appropriately set according to the application, and for example, can be 50 to 200 μm for foamed wallpaper.

  The resin sheet may be subjected to a crosslinking treatment. Examples of the crosslinking treatment include a heating treatment such as an electron beam irradiation treatment and a superheated steam treatment. When the resin composition contains the silane crosslinkable resin, a superheated steam treatment and a water crosslink treatment can be performed.

  In the electron beam irradiation treatment, for example, the resin sheet can be subjected to a crosslinking treatment by irradiating an electron beam from one side or both sides of the formed resin sheet. The conditions for electron beam irradiation depend on the thickness of the foamed resin layer, but are preferably an acceleration voltage of 150 to 300 kV and an irradiation dose of 10 to 100 kGy. When the acceleration voltage is within the above range, the electron beam can sufficiently reach deep in the thickness direction of the resin sheet, and the deterioration of the backing paper due to the electron beam can be suppressed. Further, when the irradiation dose is within the above range, it becomes easy to perform desired crosslinking on the resin sheet while suppressing yellowing of the resin sheet and changes in mechanical properties.

  The superheated steam treatment includes, for example, a method of treating superheated steam (also referred to as superheated steam) in an environment of 130 ° C to 280 ° C for 20 seconds to 15 minutes. The superheated steam treatment includes, for example, a method in which a sheet is placed in an atmosphere of a superheated steam and the superheated steam is brought into contact with the sheet. In addition, as a method of water cross-linking, a method of curing and water cross-linking in a temperature range of 40 ° C. to 70 ° C. for 1 day to 1 month under an environment of 60% or more of humidity, and specifically, 40 ° C. A method of curing under an environment of a 90% constant temperature / humidity chamber and performing water crosslinking.

  The crosslinking treatment of the resin sheet may be performed on a resin composition formed into a film, or may be performed after forming a laminated sheet described later.

[Laminated sheet]
The laminated sheet according to the present embodiment includes a base material and the resin sheet provided on the base material. The laminated sheet can be obtained by laminating a resin sheet on a base material. The method of lamination is not particularly limited, and examples thereof include a method of thermocompression bonding the resin sheet and the base material using a hot press or the like, a method of performing pressure bonding using superheated steam, and the like. According to the method of performing pressure bonding using superheated steam, it is possible to laminate onto the substrate while maintaining the molten state of the surface of the sheet-like material by the superheated steam. The transfer of the unevenness of the surface to the resin sheet can be suppressed. When the resin sheet contains a silane crosslinkable resin, the silane crosslinkable resin can be efficiently crosslinked by superheated steam.

The substrate is not particularly limited as long as it is generally used as a paper substrate such as a conventional backing paper for wallpaper. As such a substrate, for example, pulp-based flame-retardant paper impregnated with a water-soluble flame retardant such as guanidine sulfamate and guanidine phosphate, or an inorganic agent such as magnesium carbonate, aluminum hydroxide, and magnesium hydroxide. Examples include mixed inorganic papers. These weighings may be 50-300 g / m ² or 60-160 g / m ² .

  In addition, from the viewpoint of improving the adhesiveness between the base material and the resin sheet, the surface of the base material on the side where the resin sheet is provided is subjected to, for example, a corona discharge treatment, a plasma treatment, an easy adhesion treatment such as an ozone treatment. And an easy-adhesion treatment layer formed of an acrylic-butyl copolymer, polyurethane composed of isocyanate and polyol, or the like.

[Foam wallpaper]
The foamed wallpaper according to the present embodiment includes a base material and a foamed resin layer provided on the base material. Such a foamed wallpaper is, for example, a step of laminating the above-described resin sheet on a base material to obtain a laminated sheet, and a step of forming a foamed resin layer by foaming a foaming agent contained in the resin sheet. And a manufacturing method comprising:

  The foaming of the foaming agent can be performed by heating the resin sheet. The heating conditions can be appropriately set depending on the components constituting the resin sheet, and are not particularly limited. However, heating at 160 ° C to 280 ° C for 10 seconds to 120 seconds is preferable, and heating at 220 ° C to 240 ° C for 20 seconds is preferable. The heating is more preferably performed for 2 to 40 seconds, and further preferably performed at 220 ° C. for 40 seconds.

  In another embodiment, the foamed wallpaper can be obtained by a method including a step of forming a foamed resin layer by foaming a foaming agent contained in a resin sheet of the laminated sheet.

  Furthermore, in the foamed wallpaper according to the present embodiment, the surface of the foamed resin layer on the side opposite to the substrate may have an uneven shape. The method of providing the uneven shape is not particularly limited, but, for example, using heat at the time of heating and foaming, the surface side is used as a cooling embossing roll, the base material side is used as a rubber roll, and two tolls are used. A method of forming a concavo-convex shape on the surface by nip (embossing) and cooling is used. The uneven shape is not particularly limited, but includes, for example, a wood grain board conduit groove, a stone board surface unevenness, a cloth surface texture, a satin finish, a grain, a hairline, a linear groove, and the like. Can be selected as appropriate.

  The foamed wallpaper according to the present embodiment may be provided with a pattern layer and a surface protection layer. The pattern layer and the surface protective layer can be appropriately provided using a known material. If the object of the present invention can be achieved, it is not necessary to provide a pattern layer and a surface protection layer. The pattern layer and the surface protective layer can be provided by using a known printing technique such as gravure coating. The pattern layer and the surface protective layer can be provided before the foaming agent is foamed.

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

[Preparation of foam wallpaper]
(Examples 1 to 6, Comparative Examples 1 to 3)
Using a T-die having a coat hanger type manifold, using a barrier type screw having a screw diameter (D) of 65 mm and L / D = 32, the composition shown in Table 1 (the numerical values in the table indicate parts by mass) Was formed at an extrusion temperature of 125 ° C. and a thickness of 100 μm to obtain resin sheets, respectively.

  Each of the resin sheets was irradiated with an electron beam at an acceleration voltage of 200 kV and an irradiation dose of 50 kGy to crosslink the resin.

Next, the resin sheet formed in each of Examples and Comparative Examples was placed on a backing paper (manufactured by KJ Specialty Paper, WK-6651HT, weight: 65 g / cm ² ), and pressed at 5 MPa by a hot press heated at 110 ° C. And pressed for 2 minutes under the conditions described above to obtain a laminated sheet.

  After performing a corona discharge treatment on the resin sheet side surface of the obtained laminated sheet, a textile pattern was printed using a water-based ink (Hydrick WP, manufactured by Dainichi Seika Kogyo Co., Ltd.) using a gravure printing machine. Next, each laminated sheet was heated in an oven at 240 ° C. for 25 seconds to foam a foaming agent, thereby producing a foamed wallpaper.

  The following materials were used for each component shown in Table 1.

[Low density polyethylene]
Resin A: Novatec LD LC604 (manufactured by Japan Polyethylene Corporation, density = 0.918 g / cm ³ )

[Ultra low density polyethylene]
Resin B: Toughmer DF140 (manufactured by Mitsui Chemicals, density = 0.905 g / cm ³ )

[Calcium carbonate]
Filler A: Softon 1000 (manufactured by Bihoku Powder Chemical Industry)

[titanium dioxide]
Filler B: Taipaque CR-60-2 (manufactured by Ishihara Sangyo)

Blowing agent: VINHALL AC # 3C-2K (manufactured by Eiwa Chemical Co., Ltd.)

Foaming aid A: HT-00 (manufactured by Nitto Kasei Kogyo Co., Ltd., calcium stearate / zinc stearate composite, Ca: Zn molar ratio = 1: 1, melting point: 96-106 ° C.)
Foaming aid B: calcium stearate / zinc stearate complex, Ca: Zn molar ratio = 2: 1
Foaming aid C: calcium stearate / zinc stearate complex, Ca: Zn molar ratio = 1: 2
Foaming aid D: OF-101 (manufactured by ADEKA Corporation, zinc stearate, melting point: 120 to 126 ° C.)
Foaming aid E: Ca-St CP (manufactured by Nitto Kasei Kogyo Co., Ltd., calcium stearate, melting point: 150 to 160 ° C)

Lubricant: ADK STAB AP-546 (made by ADEKA)

  In addition, the melting point of the foaming aid is measured using a thermal analyzer (STA6000, manufactured by Perkinelmer. Jpn, Inc.) capable of performing differential thermal analysis measurement (DTA) under a measurement condition of a heating rate of 1.0 ° C./min. Calculated based on the obtained chart. Specifically, the temperature at which the peak of the heat of fusion started to rise (melting start temperature) and the temperature at which the peak returned to the baseline (melting end temperature) were recorded as the lower limit and upper limit of the melting point.

[Evaluation of foam wallpaper]
With respect to the produced foamed wallpaper, the expansion ratio and the ink adhesion were evaluated according to the following methods.

(Expansion ratio)
The thickness (a) of the dried foamed resin layer before foaming was measured and used as an initial value. Next, the thickness (b) of the foamed resin layer of the foamed wallpaper after foaming in a foaming furnace was measured, and (b) / (a) was calculated as the foaming ratio. Table 2 shows the results.

(Ink adhesion)
The adhesion test of the pattern layer with a tape (manufactured by Nichiban Co., Ltd., CT-24) was performed on the laminated sheet on which the woven pattern was printed. Regarding the adhesion, “○” indicates that the pattern layer remains 90% or more compared to before the test, and “△” indicates that the pattern layer has a residual ratio of 50% or more and less than 90%. Those were marked with "x". Table 2 shows the results.

[Evaluation of laminated sheet]
In the same manner as above, the laminated sheets of Examples 1 to 4 and Comparative Example 1 were obtained. For these laminated sheets, the wettability after corona treatment and the contact angle with ink were evaluated according to the following methods. Table 2 shows the results.

(Wetting)
Corona discharge treatment was applied to the surface of the laminated sheet on the resin sheet side. The surface subjected to the corona discharge treatment was subjected to a test as described in JIS K6768 using a liquid mixture for a wet tension test (mixture liquid No. 30 to No. 42 for a wet tension test, manufactured by Wako Pure Chemical Industries, Ltd.) The wetting tension (mN / m = N / mm) of the resin sheet was measured.

(Contact angle)
The contact angle was measured using a portable contact angle meter PG-3 manufactured by Matsubo Corporation, and the contact angle with respect to hydric ink (Hydrick WP, manufactured by Dainichi Seika Kogyo Co., Ltd.).

Claims (4)

Production of foamed wallpaper comprising: a base material; a foamed resin layer provided on the base material; and a pattern layer containing an aqueous ink provided on a surface of the foamed resin layer opposite to the base material. The method
A first step of preparing a laminated sheet comprising a base material and a resin sheet formed of a resin composition containing a filler, a foaming agent, a foaming aid and a resin component, which is laminated on the base material,
A second step of foaming the foaming agent contained in the resin sheet in the laminated sheet to form a foamed resin layer;
Before the second step comprises, a more Engineering providing a pattern layer containing an aqueous ink on the surface opposite to the base material of the resin sheet in the laminated sheet,
The foaming aid includes a complex of fatty acid zinc and fatty acid calcium,
The molar ratio of zinc to calcium in the composite is 3: 1 to 1: 3;
Wherein the resin component comprises a density 0.91 g / cm ³ or more 0.94 g / cm ³ or less of low density polyethylene and density 0.88 g / cm ³ or more 0.91 g / cm ³ less than the very low density polyethylene,
The content of the resin component is 20 to 80% by mass based on the total amount of the resin composition,
The content of the composite is 1 to 10 parts by mass with respect to 100 parts by mass of the resin component.
Production method.   The production method according to claim 1, wherein the resin sheet is obtained by extruding the resin composition into a film.   The production method according to claim 1, wherein the content of the composite is 10 to 150 parts by mass with respect to 100 parts by mass of the blowing agent.   The manufacturing method according to any one of claims 1 to 3, wherein the resin sheet has been subjected to a crosslinking treatment.