JP6705248B2 - Resin composition, method for producing resin sheet, method for producing laminated sheet, and method for producing foamed wallpaper - Google Patents

Description

The present invention relates to a resin composition, a method for producing a resin sheet, a method for producing a laminated sheet, and a method for producing foamed wallpaper. More specifically, the present invention relates to a resin composition that can be used for wall decoration of buildings such as detached houses, collective housing, shops, office buildings, etc., and a method for producing a resin sheet, a laminated sheet and a foamed wallpaper.

As a wallpaper used for the wall decoration of a building, 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, in consideration of the environment, a halogen-free resin such as an ethylene-vinyl acetate copolymer has been used (see, for example, Patent Documents 1 and 2 below).

In addition, in the resin composition for producing wallpaper, inorganic substances such as calcium carbonate and titanium dioxide are used for the purpose of imparting surface strength and hiding power, reducing burned calories per unit area, and reducing production cost by increasing bulk. Fillers are preferably added.

As a method for producing these foamed wallpapers, first, a resin composition containing a foaming agent and a filler is melt-extrusion coated and laminated on a substrate, or sheeting is separately performed by a T-die extrusion method, and then the By laminating the base material by dry lamination or heat lamination, a laminated sheet having a resin sheet provided on the base material is obtained. Then, if necessary, the resin sheet having the surface printed thereon is heated to decompose and foam the foaming agent. These methods are advantageous in terms of production efficiency as compared with the method of coating and drying the resin composition on the substrate.

A resin composition for a foamed wallpaper is required to be one in which a resin sheet formed into a film has a sufficient expansion ratio when foamed and is in a good foaming state in which outgassing is not noticeable. Therefore, a viscosity suitable for foaming is adjusted by performing a crosslinking treatment with an electron beam or the like after the film formation (see, for example, Patent Document 3 below). However, in the electron beam irradiation, in addition to performance problems such as yellowing the paper base material, there are also problems such as the electron beam irradiation device being expensive.

JP-A-6-47875 JP, 2001-347611, A Patent No. 3923969

The present inventors have conducted a study on a resin sheet that can be crosslinked by means other than an electron beam, and a resin sheet containing a silane crosslinkable resin can be sufficiently crosslinked by heat or moisture, resulting in a good foaming state. It was found that it can be formed. On the other hand, it was also revealed by the study of the present inventors that a gel may be generated when a resin composition containing a silane crosslinkable resin is extrusion-molded.

The present invention has been made in view of the above circumstances, and uses a resin composition that can be cross-linked by heat or moisture and is less likely to cause gelation even when extrusion-molded, and the resin composition is used. An object is to provide a method for producing a resin sheet, a method for producing a laminated sheet, and a method for producing a foamed wallpaper.

That is, the present invention is a resin composition for forming a foamed resin layer of a foamed wallpaper comprising a base material and a foamed resin layer provided on the base material, which comprises a foaming agent and a filler. And a resin component containing a silane crosslinkable resin, and the filler contains fine particles having an average particle diameter of 0.3 to 1.0 μm.

The resin composition of the present invention can be crosslinked by heat or moisture, and gel hardly occurs even when it is extrusion-molded. According to the resin composition of the present invention, a resin sheet having a sufficiently small amount of gel and capable of being crosslinked by heat or moisture can be obtained by extrusion molding. The present inventors presume the reason why such an effect is obtained as follows. First, as one of the factors causing gelation, when a masterbatch containing a silane crosslinkable resin and a filler is prepared, the silane crosslinkable resin and the filler are locally affected by the influence of water content of the filler. It is conceivable that a general crosslinking reaction will occur. It is considered that in the filler having a large particle size, the above reaction easily proceeds to a level at which it is recognized as a gel. On the other hand, by combining the fine particles having the specific average particle diameter with the silane crosslinkable resin, the progress of the reaction and the aggregation of the fillers are suppressed, and the extrusion molding is performed while securing a sufficient filling amount. The present inventors believe that the generation of gel at that time was suppressed.

The fine particles are preferably calcium carbonate. By using calcium carbonate, the cost can be reduced while obtaining the effect of the resin composition of the present invention described above.

The fine particles preferably have a fatty acid on the surface. By using the fine particles having a fatty acid on the surface, it is possible to suppress the reaction between the water of crystallization which the fine particles have, the coordination water and the silane crosslinkable resin, and to more efficiently suppress the generation of gel. it can.

The filler preferably further contains second fine particles having an average particle diameter of 0.15 to 0.25 μm. Further, the second fine particles are preferably titanium oxide. By further including the second fine particles, it is possible to further improve the hiding property while suppressing the generation of gel.

The second fine particles preferably have a polyol on the surface. By using the second fine particles having a polyol on the surface, the compatibility between the second fine particles and the resin can be further improved, and the gel generation suppressing effect and the concealing property can both be achieved at a higher level. it can.

The present invention also provides a method for producing a resin sheet, comprising a resin sheet forming step of forming a resin sheet by subjecting the resin composition according to the present invention to film formation by extrusion.

The present invention also provides a method for producing a laminated sheet, which comprises a laminated sheet forming step of laminating a resin sheet obtained by the method for producing a resin sheet according to the present invention on a substrate to obtain a laminated sheet.

The method for producing a laminated sheet comprises a crosslinking step of crosslinking a part or all of the resin component contained in the resin sheet before or during lamination on the base material, or the resin component contained in the resin sheet in the laminated sheet. A cross-linking step of cross-linking a part or the whole may be further provided.

The cross-linking is preferably performed using superheated steam. By carrying out the cross-linking reaction using superheated steam, the reaction efficiency of the cross-linking reaction can be increased, and a laminated sheet having desired properties can be efficiently produced.

Further, the present invention is a method for producing a foamed wallpaper comprising a base material and a foamed resin layer provided on the base material, wherein the laminated sheet is obtained by the method for producing a laminated sheet according to the present invention. There is provided a method for producing a foamed wallpaper, comprising a foaming step of forming a foamed resin layer by foaming a foaming agent contained in.

According to the present invention, it is possible to crosslink by heat or moisture, and a resin composition in which gel is unlikely to occur even when extrusion-molded, a method for producing a resin sheet using the resin composition, and a laminated sheet A manufacturing method and a manufacturing method of a foam wallpaper can be provided.

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

Hereinafter, each constituent component contained in the resin composition will be described in more detail.

<Foaming agent>
Examples of the foaming agent according to the present embodiment include azo foaming agents such as azodicarbonamide, hydrazide foaming agents such as p-toluenesulfonylhydrazide, and nitroso foaming agents such as N,N′-dinitrosopentamethylenetetramine. And the like. These can be used alone or in combination of two or more. The content of the foaming agent is not particularly limited, but its total amount is preferably 2 to 30 mass% based on the total amount of the resin composition. When the content of the foaming agent is within the above range, it is possible to suppress yellowing caused by the foaming agent remaining in the foamed wallpaper after foaming, and it is possible to produce a foamed wallpaper having good compression recovery and touch. ..

As the foaming agent, for example, a commercially available product such as VINIHOL AC#3C-K2 (manufactured by Eiwa Kasei Co., Ltd., an azodicarbonamide-based foaming agent) can be used.

<Filler>
The filler according to the present embodiment contains fine particles having an average particle diameter of 0.3 to 1.0 μm (hereinafter sometimes referred to as first fine particles).

In the present specification, the average particle diameter means a value obtained by the air permeation method. The average particle size of the fine particles can be measured, for example, by a specific surface area measuring method.

Examples of the first fine particles include inorganic fine particles and organic fine particles. Examples of the inorganic fine particles include calcium carbonate and titanium dioxide, and these may 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. As the first fine particles, inorganic fine particles are preferable, and calcium carbonate is more preferable.

The average particle size of the first fine particles contained in the filler according to the present embodiment maintains the performance as a filler such as surface strength, hiding power, reduction of burned calories per unit area, and reduction of manufacturing cost due to bulking. While it is possible to improve the compatibility with the resin and suppress the generation of gel even when the cross-linking reaction of the silane cross-linking resin proceeds, it is necessary to be 0.3 to 1.0 μm. is there. From the above viewpoint, the average particle size of the first fine particles is preferably 0.4 to 0.8 μm, and more preferably 0.5 to 0.7 μm.

The first fine particles contained in the filler according to the present embodiment preferably have fatty acid on the surface. By using the fine particles having a fatty acid on the surface, it is possible to suppress the reaction between the water of crystallization which the fine particles have, the coordination water and the silane crosslinkable resin, and to more efficiently suppress the generation of gel. it can. Note that the smaller the average particle size of the first fine particles, the larger the total surface area of the fine particles, and the more easily the above effects can be obtained. From such a viewpoint, the average particle size of the fine particles having a fatty acid on the surface is preferably 1.0 μm or less.

As the first fine particles, for example, Micropowder μ 3N (manufactured by Bihoku Powder Chemical Industry Co., Ltd., calcium carbonate, average particle size 0.6 μm, no surface treatment), Micropowder μ 3S (manufactured by Bihoku Powder Chemical Industry Co., Ltd., Commercially available products such as calcium carbonate, average particle size of 0.6 μm, stearic acid treatment) can be used.

The filler according to the present embodiment preferably further contains second fine particles having an average particle diameter of 0.15 to 0.25 μm from the viewpoint of further improving the hiding property while suppressing the generation of gel. Examples of the second fine particles include inorganic fine particles and organic fine particles. Examples of the inorganic fine particles include calcium carbonate and titanium dioxide, and these may 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. As the second fine particles, inorganic fine particles are preferable, and titanium dioxide is more preferable.

When the filler according to the present embodiment contains the second fine particles, the average particle diameter thereof is preferably 0.15 to 0.25 μm, but a viewpoint of imparting performance as a filler while suppressing aggregation. Therefore, the thickness is more preferably 0.18 to 0.23 μm, further preferably 0.19 to 0.22 μm.

The second fine particles preferably have a polyol on their surface. By using the fine particles having a polyol on the surface, the compatibility between the second fine particles and the resin can be further improved, and the gel generation suppressing effect and the hiding property can both be achieved at a higher level.

Examples of the second fine particles include Taipaque CR-60 (manufactured by Ishihara Sangyo Co., Ltd., titanium dioxide, average particle size 0.21 μm, no polyol treatment), Taipaque CR-60-2 (manufactured by Ishihara Sangyo Co., Ltd., titanium dioxide). , An average particle size of 0.21 μm, and a polyol treatment) can be used.

The content of the filler is not particularly limited, but the total amount thereof is preferably 10 to 70% by mass, more preferably 15 to 50% by mass, and more preferably 20 to 20% by mass based on the total amount of the resin composition. It is more preferably 30% by mass.

The content of the first fine particles contained in the filler is preferably 40 to 100% by mass, more preferably 40 to 80% by mass, and more preferably 45 to 75% by mass, based on the total amount of the filler. % Is more preferable, and 50 to 70% by mass is particularly preferable.

When the filler contains the second fine particles, the content thereof is preferably 20 to 60% by mass, more preferably 25 to 55% by mass, and more preferably 30% by mass based on the total amount of the filler. It is more preferable that the content is ˜50% by mass.

Further, the filler according to the present embodiment may contain fine particles other than the first fine particles and the second fine particles as long as the effects of the present invention are not impaired. Examples of such fine particles include Softon 1500 (manufactured by Bihoku Powder Chemical Industry Co., Ltd., calcium carbonate, average particle size: 1.5 μm, no surface treatment), Softon 1000 (manufactured by Bihoku Powder Chemical Industry Co., Ltd., calcium carbonate, average Particle size 2.2 μm, no surface treatment), Ryton A (Bihoku Powder Industry Co., Ltd., calcium carbonate, average particle size 1.8 μm, ester treatment), Ryton S-4 (Bihoku Powder Industry Co., Ltd., carbonic acid) Commercially available products such as calcium, average particle size 2.2 μm, stearic acid treatment) can be used.

In the filler according to the present embodiment, the content of fine particles having an average particle size of more than 1.0 μm is preferably 10% by mass or less based on the total amount of the filler, and the average particle size of the particles is more than 1.0 μm. It is more preferable not to include it. Further, it is preferable that the filler according to the present embodiment does not include fine particles having an average particle diameter of 3.0 μm or more.

<resin content>
The resin component according to this embodiment contains a silane crosslinkable resin.

As the silane crosslinkable resin, for example, a silane crosslinkable polyolefin resin or the like can be used. Examples of the silane-crosslinkable polyolefin-based resin include a resin in which a hydrolyzable silyl group is mainly introduced into a side chain of a polyolefin-based polymer as a matrix. Examples of such a resin include a resin in which a hydrolyzable silyl group is mainly introduced into a side chain in a polymer such as a low density polyethylene type, a high density polyethylene type, an ethylene-vinyl acetate copolymer type, a polypropylene type or the like. .. Crosslinking is carried out by hydrolysis of the substituted silyl group. It should be noted that the polyolefin-based resin having the silyl group at the terminal may be included.

The silane crosslinkable polyolefin resin is a method of randomly copolymerizing a monomer of a polyolefin polymer and a silane compound having an ethylenically unsaturated group or an epoxy group in a container, or a peroxide of a melt of the polyolefin polymer. Can be obtained by a method of graft-copolymerizing the above silane compound with. Here, the polyolefin-based polymer as a matrix can be used alone or in combination of two or more of ethylene homopolymers described below or copolymers of ethylene and other olefins. Further, as the base polyolefin-based resin, the above-mentioned polyolefin-based resin and a resin different from the above-mentioned polyolefin-based resin may be used in combination as long as mixing or dispersion of the resins is allowed. The degree of mixing or dispersion varies greatly depending on the type of extruder used, and an appropriate compatibilizer can also be used. Therefore, the combined resins cannot be unconditionally classified, but the same type of resin is preferable. Specific examples of the silane crosslinkable resin include "Rinklon" manufactured by Mitsubishi Chemical Corporation.

Examples of the silane compound having an ethylenically unsaturated group include a silane compound having a vinyl group, a silane compound having an acryloyl group, and a silane compound having a methacryloyl group. Examples of the silane compound having a vinyl group include vinyltrimethoxysilane, vinyltriethoxysilane, vinyltripropoxysilane, vinyltriisopropoxysilane, vinyltributoxysilane, vinyltripentyloxysilane, vinyltriphenoxysilane, vinyltribenzyloxy. Examples thereof include silane, vinyl trimethylenedioxysilane, vinyltriethylenedioxysilane, vinyltripropionyloxysilane, vinyltriacetoxysilane, and vinyltricarboxysilane. Examples of the silane compound having an acryloyl group include 3-acryloxypropyltrimethoxysilane. Examples of the silane compound having a methacryloyl group include 3-methacryloxypropylmethyldimethoxysilane.

Examples of the silane compound having an epoxy group include 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane and 3-glycidoxypropylmethyldimethoxysilane.

The content of the silane-crosslinkable resin in the resin composition according to the present embodiment is not particularly limited, from the viewpoint of further improving the molding stability such as the occurrence of gel and the surface roughness is less likely to occur, the total amount of the resin composition is a standard. Is preferably 5 to 25% by mass, more preferably 6 to 15% by mass, and further preferably 7 to 10% by mass.

Further, the resin component according to the present embodiment preferably further contains an ethylene homopolymer or a copolymer of ethylene and another olefin, in addition to the silane crosslinkable resin described above.

Ethylene homopolymers and copolymers of ethylene and other olefins are non-polar non-halogen thermoplastic resins, and by using these, ethylene-methyl methacrylate copolymer resin, ethylene-vinyl acetate copolymer resin. Compared with the case where a resin and a polar resin such as an ionomer resin are used, an increase in the viscosity when the amount of the filler is increased is suppressed, so that a high-quality wallpaper can be stably produced.

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

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), etc. of the low density polyethylene are not particularly limited, but the melting point is preferably 50°C to 140°C, more preferably 60°C 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 molding the resin, and the foaming agent can be prevented from decomposing during molding. On the other hand, when the melting point is 50° C. or higher, the thermal durability in actual use is easily obtained. The MFR is preferably 3 to 150, more preferably 4 to 100. When the MFR is 3 or more, shearing heat generated during molding can be suppressed, the processing temperature can be easily controlled, and decomposition of the foaming agent during molding can be suppressed. On the other hand, when the MFR is 150 or less, the mechanical strength of the produced foamed wallpaper is maintained, and a layer having excellent workability and durability is easily formed.

As the low-density polyethylene, for example, commercially available products such as Novatec LD LC802A, Novatec LD LC604, Novatec LD LC600A (all manufactured by Nippon Polyethylene Co., Ltd.), and Ube Polyethylene J2516 (manufactured by Ube Maruzen Polyethylene Co., Ltd.) can be used.

Copolymers of ethylene and other olefins include, for example, linear low-density polyethylene, ultra-low-density polyethylene, and high-density polyethylene obtained by copolymerization with comonomers. 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 having a density in the range of less than 0.85 g / cm ³ or more 0.91 g / cm ^3. The density of the ultra-low density polyethylene is preferably 0.86 g/cm ³ or more and 0.90 g/cm ³ or less, more preferably 0.87 g/cm ³ or more and 0.90 g/cm ³ or less, and further preferably 0.87 g/cm ³ or more and 0.90 g/cm ³ or less, particularly preferably 0.88 g/cm ³ or more and 0.90 g/cm ³ or less, and most preferably 0.89 g/cm ³ or more and 0.90 g /Cm ³ or less. The molecular weight, melting point, MFR, etc. of the ultra-low density polyethylene are not particularly limited, but the melting point is preferably 50 to 100°C, more preferably 55 to 90°C. When the melting point is 100° C. or lower, it is not necessary to melt the resin at a higher temperature when molding the resin, and the foaming agent can be prevented from decomposing during molding. On the other hand, when the melting point is 50° C. or higher, the thermal durability in actual use is easily obtained. The MFR is preferably 3 to 150, more preferably 4 to 100. When the MFR is 3 or more, shearing heat generated during molding can be suppressed, the processing temperature can be easily controlled, and decomposition of the foaming agent during molding can be suppressed. On the other hand, when the MFR is 150 or less, the mechanical strength of the produced foamed wallpaper is maintained, and a layer having excellent workability and durability is easily formed.

Examples of ultra-low density polyethylene include Tuffmer DF140, DF940, DF7350 (all manufactured by Mitsui Chemicals, Inc.), Kernel KJ640T (manufactured by Nippon Polyethylene Co., Ltd.), Excellen FX CX5508 (manufactured by Sumitomo Chemical Co., Ltd.), Engage 8400/8407. Commercially available products such as (manufactured by Dow Chemical Co.) and Evolue P SP90100 (manufactured by Prime Polymer Co., Ltd.) can be used.

The content of the ethylene homopolymer or the copolymer of ethylene and another olefin is preferably such that the total amount thereof is 10 to 90% by mass, and 30 to 70% by mass based on the total amount of the resin composition. It is more preferable that it is present, further preferably 40 to 70% by mass, and particularly preferably 50 to 70% by mass.

Further, the resin composition according to the present embodiment may be colored by adding a pigment or the like, if necessary. The coloring by the addition of the pigment may be transparent, semi-transparent, 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 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 flame retardants, cell regulators, stabilizers, lubricants, foaming aids and silane crosslinking aids can be used in the resin composition, if necessary.

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

Examples of the cell adjusting agent include acrylic acid ester-based resins and methacrylic acid ester-based resins.

Examples of the stabilizer include radical scavengers such as amine-based antioxidants and hindered amine-based light stabilizers, phosphorus-based and sulfur-based peroxide decomposers, and phenol-based antioxidants and other heat stabilizers. Be done.

Examples of the lubricant include fatty acid-based lubricants such as stearic acid and lauric acid, fatty acid amide-based compounds such as stearic acid amide and oleic acid amide, and metal soap-based lubricants such as zinc stearate, calcium laurate, and zinc octylate. .. As the lubricant, for example, commercially available products such as ADEKA STAB AP-546 and ADEKA STAB OF-101 (above, manufactured by ADEKA CORPORATION) can be used.

Examples of the foaming aid include urea-based agents, zinc chloride, zinc oxide, and the like, in addition to the metal soap-based lubricants described above.

Examples of the silane crosslinking aid include tin-based crosslinking aids such as dioctyltin dilaurate.

[Method for producing resin sheet]
The method for producing a resin sheet according to the present embodiment includes a resin sheet forming step of forming a resin sheet by extrusion molding the resin composition according to the present embodiment described above.

Examples of the extrusion molding method include T-die extrusion method, T-die extrusion simultaneous lamination method, T-die extrusion tandem lamination method, circular die extrusion method, circular die inflation extrusion method and the like.

The resin sheet can be produced by a known molding method such as injection molding, press molding, blow molding, calendar molding, coating molding, cast molding, dipping molding, vacuum molding, transfer molding, etc., in addition to extrusion molding.

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

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

The thickness of the resin sheet can be appropriately set depending on the application, but for example, in the case of application as a foamed wallpaper, it can be set to 50 to 200 μm.

The method for producing a resin sheet according to this embodiment may further include a crosslinking step of crosslinking a part or all of the resin component contained in the resin sheet described above. Examples of the cross-linking treatment include superheated steam treatment and water cross-linking treatment, which can increase the reaction efficiency of the cross-linking reaction and enable efficient production of a resin sheet having desired characteristics. Steam treatment is preferred.

Examples of the superheated steam treatment include a method of performing superheated steam (also referred to as superheated steam) for 20 seconds to 15 minutes in an environment of 130 to 280°C. Examples of the superheated steam treatment include a method of placing a resin sheet in a superheated steam atmosphere and bringing the resin sheet into contact with the superheated steam. Moreover, as a method of water-crosslinking, the method of carrying out water-crosslinking by curing for 1 day to 1 month in a temperature range of 40 to 70° C. in an environment of humidity of 60% or more, and specifically, 40° C. 90 %, and a method of water-crosslinking is carried out in an environment of a constant temperature and humidity chamber.

The cross-linking treatment of the resin sheet may be performed on the molded resin composition, or may be performed after forming the laminated sheet described below.

[Manufacturing method of laminated sheet]
The method for manufacturing a laminated sheet according to the present embodiment includes a laminated sheet forming step of laminating a resin sheet obtained in the resin sheet forming step on a base material to obtain a laminated sheet.

The laminating method is not particularly limited, and examples thereof include a method in which the resin sheet and the base material are thermocompression-bonded using a heat press machine, a method in which they are pressure-bonded using superheated steam, and the like. According to the method of performing pressure bonding using superheated steam, it becomes possible to laminate on the base material while maintaining the molten state of the surface of the resin sheet by the superheated steam, and by the leveling effect, the surface of the base material to be adhered It is possible to prevent the unevenness from being transferred to the resin sheet. When the resin sheet contains a silane crosslinkable resin, the silane crosslinkable resin can be efficiently crosslinked by superheated steam.

The above-mentioned substrate can be used without particular limitation as long as it is one that has been conventionally used as a paper substrate such as a backing paper for wallpaper. As such a base material, for example, a pulp-based flame-retardant paper impregnated with a water-soluble flame retardant such as guanidine sulfamate or guanidine phosphate, or an inorganic agent such as magnesium carbonate, aluminum hydroxide or magnesium hydroxide is used. Examples include mixed paper made from inorganic materials. These weighing may be a 50 to 300 g / ^{m 2,} it may be 60 to 160 / ^{m 2.}

From the viewpoint of improving the adhesiveness between the base material and the resin sheet, the surface of the base material on which the resin sheet is provided is subjected to an easy adhesion treatment such as corona discharge treatment, plasma treatment, or ozone treatment. It may be applied or may be provided with an easy-adhesion treatment layer formed of an acrylic-butyl copolymer, polyurethane composed of an isocyanate and a polyol, or the like.

The method for producing a laminated sheet according to the present embodiment includes a crosslinking step of crosslinking a part or all of the resin component contained in the resin sheet before or during lamination on the base material, or included in the resin sheet in the laminated sheet. It may further include a cross-linking step of cross-linking a part or all of the resin component. The cross-linking treatment can be the same as the method described in the method for producing the resin sheet. When the resin sheet contains a silane crosslinkable resin, laminating and crosslinking of the silane crosslinkable resin can be simultaneously performed by superheated steam.

[Method for producing foamed wallpaper]
The foam wallpaper according to the present embodiment includes a base material and a foam resin layer provided on the base material. Such a foamed wallpaper includes a foaming step of forming a foamed resin layer by foaming a foaming agent contained in the laminated sheet obtained in the laminated sheet forming step.

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, but heating at 160 to 280°C for 10 to 120 seconds is preferable, and 220 to 240°C for 20 to 40 seconds. Heating is more preferable, and heating at 220° C. for 40 seconds is even more preferable.

Furthermore, the method for producing a foamed wallpaper according to the present embodiment may include a concavo-convex shape forming step of providing a concavo-convex shape on the surface of the foamed resin layer opposite to the base material. The uneven shape forming step can be provided, for example, after the foaming step. The method for providing the uneven shape is not particularly limited, but, for example, by utilizing the heat at the time of heat foaming, the surface side is the cooling embossing roll, the substrate side is the rubber roll, and two tolls are used. Examples include a method of forming an uneven shape on the surface by nipping (embossing) and cooling. The uneven shape is not particularly limited, but examples thereof include wood grain board conduit groove, stone board surface unevenness, cloth surface texturer, satin finish, grain, hairline, and ridge groove. These can be appropriately selected according to the purpose, and a plurality of them may be combined.

The method for manufacturing the foamed wallpaper according to the present embodiment may include a printing step of providing the pattern layer and the surface protective layer. The pattern layer and the surface protective layer can be appropriately provided by using a known material. If the object of the present invention can be achieved, the pattern layer and the surface protective layer may not be provided. The pattern layer and the surface protective layer can be provided by using a known printing technique such as gravure coating. The printing process can be provided, for example, before the foaming process. That is, the pattern layer and the surface protection layer can be provided before foaming the foaming agent.

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.

[Production of resin sheet]
(Examples 1 to 4, Comparative Examples 1 to 8)
Using a T-die having a coat hanger type manipulator, a flight screw with a dull mage having a screw diameter (D) of 15 mm and L/D (screw length divided by the screw diameter)=25 is shown in Table 1. A resin composition having a composition (numerical values in the table represent parts by mass) was formed into a resin sheet at an extrusion temperature of 130° C., an extrusion time of 60 minutes and a thickness of 100 μm.

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

[Low density polyethylene]
Resin A: Novatec LD LC802A (manufactured by Nippon Polyethylene Corporation, trade name, density=0.917 g/cm ³ , MFR=7)

[Ultra low density polyethylene]
Resin B: Kernel KJ640T (manufactured by Japan Polyethylene Corporation, trade name, density=0.88 g/cm ³ , MFR=30)

[Silane crosslinkable resin]
Resin C: Wrinklon SS732N (Mitsubishi Chemical Co., Ltd., trade name, low-density polyethylene base)

[Calcium carbonate]
Filler A: Micropowder μ 3N (manufactured by Bihoku Powder Chemical Co., Ltd., trade name, average particle size=0.6 μm, no surface treatment)
Filler B: Micropowder μ 3S (manufactured by Bihoku Kouka Co., Ltd., trade name, average particle size=0.6 μm, stearic acid treatment)
Filler C: Softon 1500 (manufactured by Bihoku Powder Chemical Co., Ltd., trade name, average particle size=1.5 μm, no surface treatment)
Filler D: Softon 1000 (manufactured by Bihoku Powder Chemical Co., Ltd., trade name, average particle size=2.2 μm, no surface treatment)
Filler E: Ryton A (manufactured by Bihoku Powder Co., Ltd., trade name, average particle size=1.8 μm, ester treatment)
Filler F: Ryton B (manufactured by Bihoku Powder Co., Ltd., trade name, average particle size=2.2 μm, stearic acid treatment)

[titanium dioxide]
Filler G: Taipaque CR-60 (manufactured by Ishihara Sangyo Co., Ltd., trade name, average particle size=0.21 μm, treated with alumina)
Filler H: Taipaque CR-60-2 (manufactured by Ishihara Sangyo Co., Ltd., trade name, average particle size=0.21 μm, polyol treated)

Foaming agent: Vinylhol AC#3C-K2 (manufactured by Eiwa Chemical Industry Co., Ltd., trade name, azodicarbonamide-based foaming agent)

Foaming aid: ADEKA STAB OF-101 (trade name, manufactured by ADEKA Corporation)

Silane cross-linking aid: Linkron LZ013 (trade name, manufactured by Mitsubishi Chemical Corporation)

[Evaluation of resin sheet]
With respect to the resin sheets produced in Examples and Comparative Examples, the number of gels was measured by visual measurement. The results are shown in Table 2.

＊１：ゲル多数により計測不可

*1: Cannot be measured due to many gels

[Preparation of foam wallpaper]
On the backing paper (made by KJ special paper, WK-651HT, weight 65 g/m ² ), the resin sheet formed above was placed, and pressed for 2 minutes under the condition of a press pressure of 5 MPa with a hot press machine heated at 110° C. And heat-sealed to obtain a laminated sheet.

Furthermore, after subjecting the resin sheet side surface to corona discharge treatment, a pattern pattern is printed at 1 g/m ² using a water-based ink (Hydric WP manufactured by Dainichi Seika Kogyo Co., Ltd.) by a gravure printing machine, and gravure coating is performed. A matte surface coating agent (Nisshin Chemical Industry Co., Ltd., Vinibran 890) was applied at 2 g/m ² using a machine (Kurashiki Spinning Co., Ltd., GP-10) to prepare a pre-crosslinking original fabric.

Each of the above pre-crosslinked raw fabrics was placed in a superheated steam furnace having a steam temperature of 140° C. and an amount of superheated steam of 60 kg/hour, and sprayed with superheated steam for 5 minutes to crosslink the resin component to obtain a crosslinked laminated sheet. ..

Each of the laminated sheets obtained above was heated in an oven at 220° C. for 40 seconds to foam a foaming agent to prepare a foamed wallpaper. The following performance evaluation was performed on the produced foamed wallpaper. Table 3 shows the results of the performance evaluation of each foam wallpaper. All of the foamed wallpapers had good foamability and good bubble state, and were of practically no problem quality.

<Expansion ratio>
A cross section was obtained with a razor blade, and observed and measured with a microscope (VHX-600 (trade name) manufactured by Keyence Corporation).

<Bubble state>
The cell state was subjected to cross-sectioning with a razor blade, and the presence or absence of gas escape on the surface was visually confirmed. In addition, when the shape of the cell was uniform to some extent, it was evaluated as “◯”, and when the cell size was large and huge cells were seen, it was evaluated as “x”. If “◯”, it can be said that the bubble state is good.

Claims (10)

A resin composition for forming the foamed resin layer of a foamed wallpaper comprising a base material and a foamed resin layer provided on the base material,
A foaming agent, a filler, and a resin component containing a silane crosslinkable resin,
The filler contains fine particles having an average particle size of 0.3 to 1.0 μm,
The resin composition, wherein the fine particles are calcium carbonate. The resin composition according to claim 1, wherein the fine particles have a fatty acid on the surface. The resin composition according to claim 1 or 2, wherein the filler further contains second fine particles having an average particle diameter of 0.15 to 0.25 µm. The resin composition according to claim 3, wherein the second fine particles are titanium oxide. The resin composition according to claim 3, wherein the second fine particles have a polyol on their surfaces. A method for producing a resin sheet for a foam wallpaper, comprising a resin sheet forming step of forming a resin sheet by subjecting the resin composition according to any one of claims 1 to 5 to extrusion film formation. A method for producing a laminated sheet for foam wallpaper, comprising a laminated sheet forming step of laminating a resin sheet obtained by the method according to claim 6 on a base material to obtain a laminated sheet. Crosslinking step of crosslinking the said part or all of the tree fat content that is part of the resin sheet before or during lamination is laminated on the substrate, or the resin sheet contained ∎ You can fat content of in the laminated sheet The method for producing a laminated sheet for foamed wallpaper according to claim 7, further comprising a crosslinking step of partially or entirely crosslinking. The method for producing a laminated sheet for a foamed wallpaper according to claim 8 , wherein the cross-linking is performed using superheated steam. A method for producing a foamed wallpaper comprising a base material and a foamed resin layer provided on the base material,
A method for producing a foamed wallpaper, comprising a foaming step of forming a foamed resin layer by foaming the foaming agent contained in the laminated sheet obtained by the method according to claim 7.