JP4811318B2 - Method for producing foamed decorative sheet - Google Patents

Description

  The present invention relates to a method for producing a foamed decorative sheet.

  As a decorative sheet, a foamed decorative sheet formed by forming a foamed resin layer on a paper-based substrate or the like is known (for example, Patent Document 1).

  Conventionally, a method of forming a foamed resin layer by irradiating an electron beam from the resin layer side to crosslink the foaming agent-containing resin layer and then foaming the resin layer after the resin crosslinking is known. . Prior to foaming the foaming agent-containing resin layer, the foaming ratio can be controlled and the uniformity of the foamed cells can be increased by crosslinking the resin component. When the foamed cells are non-uniform (open bubbles), the cells may burst when the embossed plate is pressed. In order to prevent such cell bursting, it is important to make the foamed cells uniform.

  There is a demand for producing a foamed decorative sheet at a low cost. For example, a foamed decorative sheet can be produced at a low cost by increasing the content ratio of the inorganic particles in the foamed resin layer. This is because the amount of resin can be reduced.

  However, when the content ratio of the inorganic particles is increased, it becomes difficult to uniformly cross-link the entire foaming agent-containing resin layer. Therefore, after foaming, the foamed cells become non-uniform and foaming unevenness is likely to occur.

Accordingly, development of a method for producing a foamed decorative sheet having excellent smoothness at low cost is eagerly desired.
JP-A-5-192635

  Accordingly, the main object of the present invention is to provide a method for producing a foamed decorative sheet excellent in smoothness at low cost.

  As a result of intensive studies, the present inventor has found that the above problems can be solved by performing electron beam irradiation by a specific method, and has completed the present invention.

That is, this invention relates to the manufacturing method of the following foaming decorative sheet.
1. On the substrate, after forming at least a foaming agent-containing resin layer, the foaming agent-containing resin layer is resin-crosslinked, and then the foaming agent-containing resin layer after resin crosslinking is foamed,
(1) The foaming agent-containing resin layer contains 70 parts by weight or more of inorganic particles with respect to 100 parts by weight of the resin component, and has a thickness of 60 to 200 μm.
(2) The resin crosslinking is performed by irradiating the foaming agent-containing resin layer with an electron beam at least through the substrate from the substrate side.
The manufacturing method characterized by the above-mentioned.
2. The said foaming agent containing resin layer is a manufacturing method of claim | item 1 containing 70-130 weight part of inorganic particles with respect to 100 weight part of resin components.
3. Item 3. The method according to Item 1 or 2, wherein the inorganic particles are at least one selected from the group consisting of calcium carbonate, talc, and titanium dioxide.
4). Furthermore, the manufacturing method in any one of claim | item 1 -3 which irradiates an electron beam to the said foaming agent containing resin layer from the said resin layer side.
5. Item 5. The manufacturing method according to any one of Items 1 to 4, wherein the electron beam has an acceleration voltage of 50 to 300 kV.

  The production method of the present invention is preferably suitable even when the foaming agent-containing resin layer contains a large amount of inorganic particles (for example, when 70 parts by weight or more of inorganic particles are contained relative to 100 parts by weight of the resin component). The resin layer can be resin-crosslinked. As a result, it is possible to form a foamed resin layer in which the foamed cells are fine and uniform (cell shape is dense and uniform) and there is almost no foaming unevenness. That is, according to the production method of the present invention, it is possible to produce a foam wallpaper having excellent smoothness. In particular, since the cells of the foamed resin layer are fine and uniform, the foamed cells are hardly ruptured by pressing the embossed plate. Therefore, an uneven pattern can be suitably formed on the front surface of the foam wallpaper.

  In the production method of the present invention, the foaming agent-containing resin layer contains 70 parts by weight or more of inorganic particles with respect to 100 parts by weight of the resin component. Therefore, a foamed decorative sheet can be produced at a low cost.

  According to the manufacturing method of the present invention, foamed wallpaper can be particularly preferably manufactured.

In the method for producing a foamed decorative sheet according to the present invention, at least a foaming agent-containing resin layer is formed on a substrate, the foaming agent-containing resin layer is resin-crosslinked, and then the foaming agent-containing resin layer after resin crosslinking is foamed. A manufacturing method comprising:
(1) The foaming agent-containing resin layer contains 70 parts by weight or more of inorganic particles with respect to 100 parts by weight of the resin component, and has a thickness of 60 to 200 μm.
(2) The resin crosslinking is performed by irradiating the foaming agent-containing resin layer with an electron beam at least through the substrate from the substrate side.
It is characterized by that.

  According to the production method of the present invention, various foamed decorative sheets can be produced. For example, foamed wallpaper, cushion flooring, foamed leather and the like can be produced.

  Hereinafter, in the present specification, the production method of the present invention will be specifically described with a case where foamed wallpaper is produced as a representative example.

Formation of Resin Layer In the production method of the present invention, at least a foaming agent-containing resin layer is formed on the substrate. For example, an adhesive layer, a foaming agent-containing resin layer, and a surface protective layer are sequentially laminated on the substrate.

(Base material)
When producing foamed wallpaper, a paper-based substrate is usually used as the substrate.

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

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

The basis weight of the paper quality substrate is not limited, but preferably about 50 to 300 g / ^{m 2,} about 50 to 80 g / ^{m 2} is more preferable.

(Adhesive layer)
When an adhesive layer is further formed between the paper base and the foaming agent-containing resin layer, the foaming agent-containing resin layer and the paper base can be more firmly adhered to each other.

  Examples of the resin component constituting the adhesive layer include ethylene-vinyl acetate copolymer (EVA), ethylene-methyl methacrylate copolymer (EMMA), ethylene-ethyl acrylate copolymer (EEA), and ethylene-methyl acrylate copolymer. Examples thereof include at least one such as a polymer (EMA). Among these, EVA is particularly preferable.

  From the viewpoint of ease of bonding with a paper-based substrate, the MFR of the adhesive layer is preferably larger than the MFR of the resin component of the foaming agent-containing resin layer. The MFR can be measured by a test method described in JIS K 7210 (thermoplastic flow test method). As test conditions, “190 ° C., 21.18 N (2.16 kgf)” described in JIS K 6760 is adopted.

  The thickness of the adhesive layer is not limited, but is preferably about 5 to 20 μm, more preferably about 10 to 15 μm.

(Foaming agent-containing resin layer)
The foaming agent-containing resin layer contains 70 parts by weight or more, preferably 70 to 130 parts by weight, more preferably 70 to 100 parts by weight of inorganic particles with respect to 100 parts by weight of the resin component. When the content of the inorganic particles is less than 70 parts by weight with respect to 100 parts by weight of the resin component, the amount of the resin component used is relatively increased and costs are increased.

  Examples of the inorganic particles include inorganic fillers and inorganic pigments. By using an inorganic filler, an effect of suppressing see-through, an effect of improving surface characteristics, and the like are obtained. Moreover, the ground color of a base material can be concealed by using an inorganic pigment.

  Examples of the inorganic filler include calcium carbonate, talc, silica, aluminum hydroxide, magnesium hydroxide, antimony trioxide, zinc borate, and a molybdenum compound. Inorganic pigments include titanium dioxide, 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, Examples include ultramarine blue, bitumen, cobalt blue, chromium oxide, cobalt green, aluminum powder, bronze powder, titanium mica, and zinc sulfide. These inorganic particles can be used alone or in combination of two or more. In particular, the inorganic particles are preferably at least one selected from the group consisting of calcium carbonate, talc and titanium dioxide. Calcium carbonate and talc are inexpensive and versatile. Titanium dioxide is particularly excellent in terms of whiteness and concealment.

  The resin constituting the foaming agent-containing resin layer is not limited, but a polyolefin resin is suitable.

  Examples of the polyolefin resin include polyethylene, polypropylene, polybutene, polymethylpentene, ethylene-propylene copolymer, EVA, ethylene-acrylic acid copolymer (EAA), EMMA, ethylene-propylene-butene copolymer, polyolefin. And thermoplastic elastomers. Among these, EVA is preferable.

  When EVA is used, the vinyl acetate content is preferably 10 to 25% by weight. When EVA having a vinyl acetate content within such a range is used, good scratch resistance can be imparted to the foamed wallpaper.

  As a foaming agent, organic foaming agents, such as a nitroso compound, an azo compound, a sulfonyl hydrazide compound, an azide compound, can be used, for example. Examples of the nitroso compound include N, N'-dimethyl-N, N'-dinitrosoterephthalamide, N, N'-dinitrosopentamethylenetetramine and the like. Examples of the azo compound include azodicarbonamide (ADCA), azobisisobutyronitrile, azocyclohexylnitrile, azodiamminobenzene, barium azodicarboxylate, and the like. Examples of the sulfonyl hydrazide compound include benzenesulfonyl hydrazide, toluenesulfonyl hydrazide, diphenylsulfone-3,3'-disulfonyl hydrazide and the like. Examples of the azide compound include calcium azide, 4,4'-diphenyldisulfonyl azide, p-toluenesulfonyl azide and the like. These foaming agents can be used alone or in combination of two or more. In particular, it is preferable to use ADCA as a foaming agent.

  The content of the foaming agent may be in a range that does not hinder the effects of the present invention, and may be set as appropriate according to the type of foaming agent to be used. For example, when ADCA is used as the foaming agent, the foaming agent-containing resin layer preferably contains 2.5 to 4.5 parts by weight of ADCA with respect to 100 parts by weight of the resin component. When the content of ADCA is 2.5 parts by weight or more with respect to 100 parts by weight of the resin component, it is easy to stably obtain a foamed resin layer having a target foaming ratio. Moreover, an embossed pattern can be shaped suitably. When the content of ADCA is 4.5 parts by weight or less with respect to 100 parts by weight of the resin component, a foamed wallpaper excellent in embossing property and light resistance can be suitably obtained.

  The foaming agent-containing resin layer may further contain an organic pigment. Examples of the organic pigment 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). These can be used alone or in combination of two or more. The amount of the organic pigment used is not particularly limited, and may be appropriately set in consideration of the design properties of the foamed wallpaper to be produced.

  The foaming agent-containing resin layer may further contain a foaming aid. Although it does not specifically limit as a foaming adjuvant, Fatty acid zinc is preferable. Here, fatty acid zinc means what formed the salt from zinc and a fatty acid. In the present specification, the fatty acid zinc is not included in the concept of the inorganic particles. By containing fatty acid zinc, the fluctuation | variation of the expansion ratio of a foamed resin layer can be suppressed effectively. Although it does not specifically limit as said fatty-acid salt zinc, C8-C18 fatty acid zinc can be used. Among these, zinc stearate is particularly preferable.

  Content of the foaming assistant in the said foaming agent containing resin layer is not specifically limited, What is necessary is just to set suitably according to the kind etc. of foaming assistant. For example, when fatty acid zinc is used as the foaming aid, it is preferable to contain 1.5 to 3.5 parts by weight of fatty acid zinc with respect to 100 parts by weight of the resin component. When the content of the fatty acid zinc is 1.5 parts by weight or more, the ADCA decomposition promoting effect can be sufficiently exerted and the foaming characteristics can be improved. As a result, the embossing formability of the foamed wallpaper can be improved. In addition, a more uniform cell shape can be obtained. When the content of fatty acid zinc is 3.5 parts by weight or less, the ADCA decomposition promoting effect can be moderately suppressed, and when the embossed pattern is formed on the foam, the cell bursts. Problems such as insufficiency can be effectively solved.

  The thickness of the foaming agent-containing resin layer is 60 to 200 μm, preferably 80 to 120 μm. When the thickness of the foaming agent-containing resin layer is less than 60 μm, the obtained foamed wallpaper cannot function as a wallpaper and lacks practicality. When the thickness of the foaming agent-containing resin layer exceeds 200 μm, foaming unevenness may occur.

(Surface protective layer)
The resin constituting the surface protective layer is preferably an ethylene-methacrylic acid copolymer (EMAA). By using EMAA as a resin component, the scratch resistance of the foamed wallpaper can be improved. The content of EMAA is preferably 70 to 100% by weight.

  The surface protective layer may contain a resin such as hydrogenated petroleum resin or EVA in addition to EMAA as long as the effect of the present invention is not hindered. The surface protective layer may further contain additives such as acrylate monomers and oligomers.

  Although the thickness of a surface protective layer is not limited, about 5-30 micrometers is preferable and about 10-20 micrometers is more preferable.

(Method for forming a resin layer on a substrate)
The method for forming the adhesive layer, the foaming agent-containing resin layer, and the surface protective layer in this order on the substrate (paper substrate) is not particularly limited. For example, a composition for forming an adhesive layer, a composition for forming a foaming agent-containing resin layer, and a composition for forming a surface protective layer are placed in separate cylinders on a paper substrate. It can be manufactured by extruding at the same time.

Resin crosslinking treatment In the production method of the present invention, the foaming agent-containing resin layer is resin-crosslinked. Prior to foaming the foaming agent-containing resin layer, the foaming ratio can be suitably controlled by resin crosslinking the foaming agent-containing resin layer.

  The resin crosslinking is performed by allowing the foaming agent-containing resin layer to be irradiated with an electron beam through the base material at least from the base material side. When the foaming agent-containing resin layer is irradiated with an electron beam from the resin layer side as in the past, if the foaming agent-containing resin layer contains a large amount of inorganic particles, the foaming agent-containing resin layer is sufficiently resin-crosslinked. I can't. For this reason, foam cells having non-uniform cell shapes and sizes may be formed, and foam unevenness may occur.

  The electron beam irradiation is performed, for example, by irradiating an electron beam from a known electron beam irradiation apparatus.

  The acceleration voltage of the electron beam is appropriately set according to the thickness of the foaming agent-containing resin layer. 50-300 kV is preferable and, as for the acceleration voltage in the case of resin-crosslinking the foaming agent containing resin layer whose thickness is 60-200 micrometers, 150-300 kV is more preferable. When the acceleration voltage is 50 to 300 kV, it is possible to sufficiently crosslink the foaming agent-containing resin layer while effectively preventing generation of harmful X-rays.

  10-70 kGy is preferable and, as for the irradiation amount of an electron beam, 30-50 kGy is more preferable. With such an irradiation amount, the resin component can be sufficiently crosslinked without impairing the flexibility of the foamed resin layer, and excellent wear resistance and scratch resistance are exhibited. Moreover, if there exists this irradiation amount, even when a foamed resin layer is immersed in boiling water, it will be a grade which does not shrink substantially.

  In addition to electron beam irradiation from the base material side, the foaming agent-containing resin layer may be irradiated with an electron beam from the foaming agent-containing resin layer side (the side opposite to the base material). By using both electron beam irradiation from the paper-based substrate side and electron beam irradiation from the resin layer side, the foaming agent-containing resin layer can be cross-linked more reliably, and a foamed resin layer having a dense and uniform cell shape can be obtained. Can be formed.

  The electron beam irradiation from the resin layer side may be performed before the electron beam irradiation from the paper base material side or after the electron beam irradiation from the paper base material side. In particular, it is preferable to perform electron beam irradiation from the resin layer side after performing electron beam irradiation from the paper substrate side. After performing electron beam irradiation from the paper base material side, a foamed resin layer having a denser cell shape can be formed by performing electron beam irradiation from the resin layer side. The electron beam irradiation from the resin layer side may be performed simultaneously with the electron beam irradiation from the paper substrate side.

  What is necessary is just to set suitably the acceleration voltage and irradiation amount at the time of irradiating an electron beam from the said resin layer side according to the thickness etc. of a surface protective layer. For example, when the thickness of the surface protective layer is 10 to 20 μm and the thickness of the foaming agent-containing resin layer is 60 to 200 μm, the acceleration voltage is preferably 50 to 300 kV, and more preferably 125 to 200 kV. The amount of irradiation is in the same range as above.

  The surface protective layer may be resin-crosslinked. For example, the surface protective layer can be cross-linked by irradiating an electron beam from the resin layer side. By subjecting the surface protective layer to resin crosslinking, a foamed wallpaper having excellent scratch resistance can be obtained. The acceleration voltage when the surface protective layer is crosslinked with a resin is preferably 50 to 200 kV, and more preferably 150 to 200 kV. The irradiation dose is preferably 10 to 70 kGy, more preferably 30 to 50 kGy.

Foaming treatment The foaming agent-containing resin layer after the resin crosslinking is foamed. Specifically, the resin layer is foamed by heat treatment. Thereby, a foamed resin layer is formed. The heat treatment conditions are not limited and can be appropriately set according to the type of the foaming agent, but are usually preferably about 160 to 300 ° C, more preferably about 220 to 240 ° C. The heat treatment time is not limited and can be appropriately set according to the heat treatment temperature, but is usually preferably about 20 to 60 seconds, and more preferably about 25 to 40 seconds. For the heat treatment, for example, a known foaming furnace can be used.

The expansion ratio of the foamed resin layer (the ratio viewed from the unfoamed resin layer) is not particularly limited, but is usually 4 times or more, preferably about 4 to 8 times. If the expansion ratio is too low, it is difficult to give an excellent appearance design. On the other hand, if the expansion ratio is too high, the foamed resin layer becomes mechanically weak, and the scratch resistance tends to decrease.
The thickness of the foamed resin layer is not limited, but is preferably about 400 to 1000 μm, and more preferably about 500 to 800 μm.

The front surface of the embossed foam wallpaper may be provided with an uneven pattern by embossing.

  The embossed pattern can be given by, for example, a known embossed plate. For example, a desired embossed pattern can be formed by pressing the embossed plate after heating and softening the front surface of the foamed resin layer. Embossed patterns include wood grain plate conduit grooves, stone plate surface irregularities, cloth surface textures, satin texture, sand texture, hair lines, and multi-line grooves.

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

Test Example 1 (Smoothness)
The smoothness of the surface of the foamed resin layer was confirmed by visual observation. The case where there was no foaming unevenness and the foamed cells were fine and uniform was evaluated as ◯, the case where some foaming unevenness was observed as Δ, and the case where foaming unevenness was observed as x.

Test example 2 (cell shape)
The cell shape of the cross section of the foamed resin layer was confirmed by visual observation. When the cell shape was dense and there was no open cell, the evaluation was ○, when the cell shape was not fine, but the cell shape was low, Δ, and when the cell shape was not dense and there were many open cells, the evaluation was ×.

Example 1
In order to form a foaming agent containing resin layer, the composition containing the component of following Table 1 was prepared.

The above composition was melted, and a foaming agent-containing resin layer was laminated on a paper substrate having a thickness of 110 μm (basis weight 70 g / m ² ) (thickness of the foaming agent-containing resin layer: 100 μm).

  Then, the electron beam (acceleration voltage: 150 kV, irradiation amount: 30 kGy) was irradiated from the paper-like base material side of the obtained laminated body, and EVA contained in the foaming agent-containing resin layer was crosslinked.

  The laminate was heated in a gear oven at 220 ° C. for 30 seconds. Thereby, the foaming agent was decomposed, and the foaming agent-containing resin layer was used as the foamed resin layer.

  Through the above process, a foam wallpaper was produced.

  Table 2 shows the evaluation results regarding the smoothness of the surface of the foamed resin layer and the cell shape of the cross section of the foamed resin layer.

Example 2
After irradiating an electron beam (acceleration voltage: 150 kV, irradiation amount: 30 kGy) from the paper substrate side of the obtained laminate, an electron beam (acceleration voltage: 150 kV, irradiation amount: 30 kGy) is further applied from the resin layer side of the laminate. ) Was used to produce a foam wallpaper in the same manner as in Example 1 except that EVA contained in the foaming agent-containing resin layer was crosslinked.

  Table 2 shows the evaluation results regarding the smoothness of the surface of the foamed resin layer and the cell shape of the cross section of the foamed resin layer.

Comparative Example 1
A foam wallpaper was produced in the same manner as in Example 1 except that the electron beam was irradiated from the resin layer side of the obtained laminate.

  Table 2 shows the evaluation results regarding the smoothness of the surface of the foamed resin layer and the cell shape of the cross section of the foamed resin layer.

Reference example 1
A foamed wallpaper was produced in the same manner as in Example 1 except that the content of calcium carbonate was 40 parts by weight (the content of inorganic particles was 60 parts by weight).

  Table 3 shows the evaluation results regarding the smoothness of the surface of the foamed resin layer and the cell shape of the cross section of the foamed resin layer.

Reference example 2
A foamed wallpaper was produced in the same manner as in Example 2 except that the content of calcium carbonate was 40 parts by weight (the content of inorganic particles was 60 parts by weight).

  Table 3 shows the evaluation results regarding the smoothness of the surface of the foamed resin layer and the cell shape of the cross section of the foamed resin layer.

Comparative Reference Example 1
A foam wallpaper was produced in the same manner as in Comparative Example 1 except that the content of calcium carbonate was 40 parts by weight (the content of inorganic particles was 60 parts by weight).

  Table 3 shows the evaluation results regarding the smoothness of the surface of the foamed resin layer and the cell shape of the cross section of the foamed resin layer.

Example 3
A foam wallpaper was produced in the same manner as in Example 1 except that the acceleration voltage was 175 kV.

  Table 4 shows the evaluation results regarding the smoothness of the surface of the foamed resin layer and the cell shape of the cross section of the foamed resin layer.

Example 4
After irradiating an electron beam (acceleration voltage: 175 kV, irradiation amount: 30 kGy) from the paper substrate side of the obtained laminate, an electron beam (acceleration voltage: 175 kV, irradiation amount: 30 kGy) is further applied from the resin layer side of the laminate. ) Was used to produce a foam wallpaper in the same manner as in Example 1 except that EVA contained in the foaming agent-containing resin layer was crosslinked.

  Table 4 shows the evaluation results regarding the smoothness of the surface of the foamed resin layer and the cell shape of the cross section of the foamed resin layer.

Comparative Example 2
A foam wallpaper was produced in the same manner as in Example 3 except that the electron beam was irradiated from the resin layer side of the obtained laminate.

  Table 4 shows the evaluation results regarding the smoothness of the surface of the foamed resin layer and the cell shape of the cross section of the foamed resin layer.

Reference example 3
A foamed wallpaper was produced in the same manner as in Example 3 except that the calcium carbonate content was 40 parts by weight (inorganic particle content 60 parts by weight).

  Table 5 shows the evaluation results regarding the smoothness of the surface of the foamed resin layer and the cell shape of the cross section of the foamed resin layer.

Comparative Reference Example 2
A foamed wallpaper was produced in the same manner as in Comparative Example 2 except that the calcium carbonate content was 40 parts by weight (inorganic particle content 60 parts by weight).

  Table 5 shows the evaluation results regarding the smoothness of the surface of the foamed resin layer and the cell shape of the cross section of the foamed resin layer.

Example 5
A foam wallpaper was produced in the same manner as in Example 1 except that the acceleration voltage was 200 kV.

  Table 6 shows the evaluation results regarding the smoothness of the surface of the foamed resin layer and the cell shape of the cross section of the foamed resin layer.

Comparative Example 3
A foam wallpaper was produced in the same manner as in Example 5 except that the electron beam was irradiated from the resin layer side of the obtained laminate.
Table 6 shows the evaluation results regarding the smoothness of the surface of the foamed resin layer and the cell shape of the cross section of the foamed resin layer.

Reference example 4
A foam wallpaper was produced in the same manner as in Example 5 except that the content of calcium carbonate was 40 parts by weight (the content of inorganic particles was 60 parts by weight).

  Table 7 shows the evaluation results regarding the smoothness of the surface of the foamed resin layer and the cell shape of the cross section of the foamed resin layer.

Comparative Reference Example 3
A foamed wallpaper was produced in the same manner as in Comparative Example 3 except that the calcium carbonate content was 40 parts by weight (inorganic particle content 60 parts by weight).

  Table 7 shows the evaluation results regarding the smoothness of the surface of the foamed resin layer and the cell shape of the cross section of the foamed resin layer.

Example 6
In order to form a foaming agent containing resin layer, the composition containing the component of following Table 8 was prepared.

  In order to form the surface protective layer, 100 parts by weight of EMAA (product name “Nucleel N1560”, MFR: 60 g / 10 min, MA content: 15 wt%, manufactured by Mitsui DuPont Polychemical) was prepared.

  In order to form an adhesive layer, 100 parts by weight of EVA (product name “Evaflex EV150”, MFR: 30 g / 10 min, VA content: 33% by weight, manufactured by Mitsui DuPont Polychemical) was prepared.

The resin and the resin-containing composition were melted, and three layers were coextruded and laminated on a paper substrate (basis weight 70 g / m ² ) having a thickness of 110 μm using a three-type three-layer multi-manifold T-die extruder. The three-layer coextrusion lamination was carried out in the order of adhesive layer / foaming agent-containing resin layer / surface protective layer so that the paper substrate and the adhesive layer were in contact with each other. The thickness of each layer was 10 μm / 100 μm / 10 μm in the above order. In this T-die extruder, the temperatures of the non-foamed resin layer forming cylinder, the foaming agent-containing resin layer forming cylinder, and the adhesive layer forming cylinder were 135 ° C., 115 ° C., and 100 ° C., respectively. The die temperatures were all 120 ° C.

  Thereafter, an electron beam (200 kV, 30 kGy) was irradiated from the paper-based substrate side of the obtained laminate to crosslink EVA contained in the foaming agent-containing resin layer.

  And the said laminated body was heated for 25 to 38 seconds at 200 degreeC in gear oven. Thereby, the foaming agent was decomposed, and the foaming agent-containing resin layer was used as the foamed resin layer.

  Through the above process, a foam wallpaper was produced.

  A photograph of the surface of the foamed resin layer of the obtained foamed wallpaper and a photograph of a cross section of the foamed resin layer are shown in FIG.

  Table 9 shows the evaluation results regarding the smoothness of the surface of the foamed resin layer and the cell shape of the cross section of the foamed resin layer.

Example 7
After irradiating an electron beam (150 kV, 30 kGy) from the paper substrate side of the obtained laminate, further irradiating an electron beam (150 kV, 30 kGy) from the resin layer side of the laminate, a foaming agent-containing resin layer A foamed wallpaper was prepared in the same manner as in Example 6 except that EVA contained in the was crosslinked.

  FIG. 2 shows a photograph of the surface of the foamed resin layer of the resulting foamed wallpaper and a photograph of the cross section of the foamed resin layer.

  Table 9 shows the evaluation results regarding the smoothness of the surface of the foamed resin layer and the cell shape of the cross section of the foamed resin layer.

Comparative Example 4
A foam wallpaper was produced in the same manner as in Example 6 except that the electron beam was irradiated from the resin layer side of the obtained laminate.

  A photograph of the surface of the foamed resin layer of the obtained foamed wallpaper and a photograph of the cross section of the foamed resin layer are shown in FIG.

  Table 9 shows the evaluation results regarding the smoothness of the surface of the foamed resin layer and the cell shape of the cross section of the foamed resin layer.

FIG. 1 shows a photograph of the foamed resin layer surface of the foamed wallpaper obtained in Example 6 and a photograph of a cross section of the foamed resin layer. FIG. 2 shows a photograph of the foamed resin layer surface of the foamed wallpaper obtained in Example 7 and a photograph of the cross section of the foamed resin layer. FIG. 3 shows a photograph of the foamed resin layer surface of the foamed wallpaper obtained in Comparative Example 4 and a photograph of a cross section of the foamed resin layer.

Claims (5)

On the substrate, after forming at least a foaming agent-containing resin layer, the foaming agent-containing resin layer is resin-crosslinked, and then the foaming agent-containing resin layer after resin crosslinking is foamed,
(1) The foaming agent-containing resin layer contains 70 parts by weight or more of inorganic particles with respect to 100 parts by weight of the resin component, and has a thickness of 60 to 200 μm.
(2) The resin crosslinking is performed by irradiating the foaming agent-containing resin layer with an electron beam at least through the substrate from the substrate side.
The manufacturing method characterized by the above-mentioned.   The said foaming agent containing resin layer is a manufacturing method of Claim 1 containing 70-130 weight part of inorganic particles with respect to 100 weight part of resin components.   The manufacturing method according to claim 1 or 2, wherein the inorganic particles are at least one selected from the group consisting of calcium carbonate, talc, and titanium dioxide.   Furthermore, the manufacturing method in any one of Claims 1-3 which irradiates an electron beam to the said foaming agent containing resin layer from the said resin layer side.   The said electron beam is a manufacturing method in any one of Claims 1-4 whose acceleration voltage is 50-300 kV.

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