JP6548980B2 - Sheet and method of manufacturing the sheet - Google Patents

Description

  The present invention relates to a sheet and a method of manufacturing the sheet.

  Conventionally, in order to impart adhesiveness and adhesiveness to foams, adhesive processing suitable for each application, such as laminating an adhesive and adhesive layer, applying a hot melt adhesive, impregnating with an adhesive, etc. Often applied.

  For example, Patent Document 1 proposes, as a pressure-sensitive adhesive tape suitable for joining non-smooth surfaces, a flexible foam sheet as a substrate provided with a pressure-sensitive adhesive / adhesive layer thereon. In addition, Patent Document 2 proposes an adhesive sheet using a foam sheet obtained by mechanically stirring an acrylic emulsion as a base material.

  However, since the open-cell foam consisting only of an acrylic emulsion is weak against splitting and is prone to material breakage, Patent Document 3 discloses an acrylic in which closed cells and open cells are mixed using inorganic and organic foams. A method of foam sheet obtained by mechanically stirring a system emulsion has been proposed.

  Further, Patent Document 4 proposes a sheet for an irregular surface, which is obtained by laminating an acrylic foam thinly on a mesh-like knitted fabric such as a non-woven fabric to give flexibility and enabling sticking to an uneven surface. .

Japanese Patent Application Laid-Open No. 47-30743 JP-A-63-89585 Unexamined-Japanese-Patent No. 4-45184 JP, 2011-136418, A

  However, conventional foam sheets have at least one of the following problems. First, there is a problem that conventional foam sheets do not have sufficient adhesion to adherends such as surface-treated glass and wallpaper having asperities. In addition, the conventional foam sheet peels from the adherend when the foam sheet itself has a weight or when any load is attached to the foam sheet, or lacks long-term retention of adhesion. There is a problem of Furthermore, when the conventional foam sheet peels from a to-be-adhered body, the foam sheet itself has a subject that it is not suitable for repeated use, such as material destruction and agglutination fall.

  Then, an object of this invention is to provide the sheet | seat which can maintain sufficient adhesive strength with respect to adherends, such as surface-treated glass and the wallpaper which has an unevenness | corrugation, for a long period, and can use repeatedly.

  Means for Solving the Problems As a result of intensive studies to solve the above problems, the present inventors set a method for producing a sheet having a specific porous foam layer obtained from an acrylic emulsion and an ethylene vinyl acetate copolymer resin emulsion. As a result, it has been found that a sheet capable of achieving the above object can be obtained, and the present invention has been completed.

That is, the present invention (1) is
A method of producing a sheet having at least a porous foam layer, comprising:
The production method comprises the steps of: foaming an emulsion composition containing the emulsion, a crosslinking agent and a foaming agent using a mechanical floss method to form a foam, and curing the foam.
The emulsion contains an acrylic emulsion and an ethylene vinyl acetate copolymer emulsion,
The weight ratio of the ethylene-vinyl acetate copolymer emulsion (solid content) to the acrylic emulsion (solid content) in the emulsion composition (the ethylene-vinyl acetate copolymer emulsion / the acrylic emulsion) is 0.05 ~ 1.7,
Weight ratio of the crosslinking agent to the acrylic emulsion (solid content) and the ethylene-vinyl acetate copolymer emulsion (solid content) in the emulsion composition {the crosslinking agent / (the acrylic emulsion + the ethylene vinyl acetate copolymer Polymer emulsion)} is 0.01-0.12, It is a manufacturing method of the sheet characterized by the above-mentioned.
The present invention (2) is
The emulsion composition contains, as the ethylene-vinyl acetate copolymer emulsion, at least two ethylene-vinyl acetate copolymer emulsions,
The two ethylene vinyl acetate copolymer emulsions are the method for producing a sheet according to the invention (1), wherein the viscosity (mPa · s) and / or the glass transition temperature are different from each other.
The present invention (3) is
Among the two ethylene vinyl acetate copolymer emulsions, the viscosity of one ethylene vinyl acetate copolymer emulsion is 2,000 to 4,000 mPa · s, and the viscosity of the other ethylene vinyl acetate copolymer emulsion is It is a manufacturing method of the sheet | seat of invention (2) of 500-1,500 mPa * s lower than the viscosity of said one ethylene vinyl acetate copolymer emulsion.
The present invention (4) is
Of the two ethylene vinyl acetate copolymer emulsions, the glass transition temperature of one ethylene vinyl acetate copolymer emulsion is -30 ° C to 30 ° C, and the glass transition temperature of the other ethylene vinyl acetate copolymer emulsion Is a method for producing a sheet according to the invention (2) or (3), wherein the temperature is at least 5 ° C. lower than the glass transition temperature of the one ethylene-vinyl acetate copolymer emulsion.
The present invention (5) is
The average particle diameter of the said ethylene vinyl acetate copolymer emulsion is a manufacturing method of the sheet as described in any one of invention (1)-(4) which is 1.0 micrometer or less.
The present invention (6) is
It is a manufacturing method of the sheet as described in any one of invention (2)-(5) whose difference of the average particle diameter of said 2 types of ethylene vinyl acetate copolymer emulsion is 0.1-0.5 micrometer.
The present invention (7) is
In the method for producing a sheet according to any one of the inventions (1) to (6), both of the glass transition temperature of the acrylic emulsion and the glass transition temperature of the ethylene vinyl acetate copolymer emulsion are −10 ° C. or lower. is there.
The present invention (8) is
The sheet according to any one of the inventions (1) to (7), further comprising a first layer provided on one side of the porous foam layer.
The present invention (9) is
The sheet according to the invention (8), wherein the sheet further comprises a second layer laminated on the first layer.
The present invention (10) is
The sheet according to the invention (8) or (9), wherein the first layer or the second layer is a layer having a function as a printing layer, a reflective layer or a whiteboard.
The present invention (11) is
The density of the porous foam layer is 150 to 300 kg / m ³ ,
The thickness of the porous foam layer is 0.5 to 2.0 mm,
The average cell diameter of the porous foam layer is 30 to 200 μm,
The delamination strength of the porous foam layer is 3.0 N / 12 mm or more,
The 25% compressive load of the porous foam layer is 2.0 to 11.0 kPa,
The adhesive strength of the said porous foam layer is a manufacturing method of the sheet as described in any one of invention (1)-(10) which is 0.4-2.5 N / 24 mm.
The present invention (12) is
A sheet having at least a porous foam layer,
The porous foam layer contains an acrylic resin and an ethylene vinyl acetate copolymer resin,
The density of the porous foam layer is 150 to 300 kg / m ³ ,
The thickness of the porous foam layer is 0.5 to 2.0 mm,
The average cell diameter of the porous foam layer is 30 to 200 μm,
The cells of the porous foam layer are formed by mechanical floss method,
The delamination strength of the porous foam layer is 3.0 N / 12 mm or more,
The 25% compressive load of the porous foam layer is 2.0 to 11.0 kPa,
The adhesive strength of the porous foam layer is 0.4 to 2.5 N / 24 mm.
The present invention (13) is
The sheet according to the invention (12), further comprising a first layer provided on one side of the porous foam layer.
The present invention (14) is
The sheet according to invention (13), further comprising a second layer laminated on the first layer.
The present invention (15) is
The sheet according to the invention (13) or (14), wherein the first layer or the second layer is a layer having a function as a printing layer, a reflective layer or a whiteboard.

Here, in the present invention, “self-adhesiveness” refers to adhesion to an adherend when it is pressed from the properties of the material without applying (including providing an adhesive layer) or impregnating a pressure-sensitive adhesive. However, when it peels off, it does not transfer to the adherend but it has the property of being able to be peeled off from the joint. The “semi-continuous cell structure” is a structure in which the pores (holes) between adjacent cells are smaller than in the case of the open cells, and different from the closed cells, the cells have small pores, and comply with JIS L 1096 A method And a value of 2 [ml / cm ² / s] or more and less than 80 [ml / cm ² / s] as measured using a Frazier-type breathability tester.

  Further, in the present invention, the “interlayer peel strength” is one index of the material strength of the sheet according to the present invention, and means the stress at the time of tearing in the case of T-peel. Specifically, the strength can be measured by the test method described later.

  According to the present invention, it is possible to provide a sheet capable of maintaining sufficient adhesion for a long period of time to adherends such as surface-treated glass and wallpaper having asperity, and which can be repeatedly used. The pressure-sensitive adhesive sheet according to the present invention can be applied to various applications.

It is a conceptual sectional view of a sheet which consists only of a porous foam layer concerning this form. It is a conceptual sectional view of a sheet which has a surface layer concerning this form. It is a conceptual sectional view of a sheet which has a surface layer and a functional layer concerning this form. It is a cross-sectional SEM photograph of the semi-open cell structure of the porous foam which concerns on this form, an open cell structure, and a closed cell structure. It is a photograph of the member used for a sticking test. It is a photograph which shows an outline of a pasting examination. It is a schematic diagram of the cross section of the wallpaper used for the sticking test.

  Hereinafter, although the suitable embodiment of the present invention is described in detail, these are examples to the last, and the present invention is not limited to the following modes.

The sheet | seat which concerns on this form, and its manufacturing method are demonstrated in order of the following.
1 Structure of sheet 2 Manufacturing method of sheet 3 Properties of sheet 4 Application of sheet

[Construction]
FIG. 1 is a schematic cross-sectional view of a sheet 100 consisting only of a porous foam layer. As described later, the porous foam layer itself can be provided with a function to double as a functional layer. FIG. 2 is a conceptual cross-sectional view of a sheet 100 having a first layer (surface layer). As shown in FIG. 2, the sheet 100 according to this embodiment is a sheet-like laminate having a porous foam layer 110 and a first layer 120 on one side of the porous foam layer 110. it can. FIG. 3 is a schematic cross-sectional view of a sheet 100 further having a second layer 130 (surface layer) above the first layer. In addition, between the porous foam layer and the first layer, between the first layer and the second layer, on the second layer (that is, on the side opposite to the first layer), one or more layers. May exist.

  Hereinafter, the porous foam layer 110, the first layer (in the case where the layer is a surface layer, for example, the layer may be a functional layer in the case of a two-layer structure) and the second layer (the layer is a surface layer) In the case of, for example, a three-layer structure, the layer may be a functional layer in the case of, for example, three layers, will be sequentially described.

«Porous foam layer»
The porous foam layer 110 according to the present embodiment functions as a layer having self-adhesive properties of the material and adhering to an adherend without applying or impregnating a pressure-sensitive adhesive. In addition, since the porous foam layer 110 in contact with the adherend has a semi-open cell structure, it adheres to the adherend by a suction cup effect. Since the porous foam layer 110 has high flexibility and stretchability, it can be stuck with strong adhesive strength even to an adherend having irregularities on the surface such as surface treated glass and wallpaper. However, it may be configured to apply an adhesive as required. Here, in the present invention, “self-adhesiveness” refers to adhesion to an adherend when it is pressed from the properties of the material without applying (including providing an adhesive layer) or impregnating a pressure-sensitive adhesive. However, when it peels off, it does not transfer to the adherend but it has the property of being able to be peeled off from the joint. The “semi-continuous cell structure” is a structure in which the pores (holes) between adjacent cells are smaller than in the case of the open cells, and different from the closed cells, the cells have small pores, and comply with JIS L 1096 A method And a value of 2 [ml / cm ² / s] or more and less than 80 [ml / cm ² / s] as measured using a Frazier-type breathability tester.

  And, since the porous foam layer 110 has a semi-continuous cell structure, it is difficult for air accumulation to be made, and even when it is possible, air can be easily released only by pressing from above.

  Furthermore, since it does not transfer to a to-be-adhered body and can be peeled off from a junction part, since it does not apply | coat or impregnate an adhesive at the time of peeling, it can use repeatedly. From this, when it is set as a structure which apply | coats an adhesive, it is preferable that there are few application parts of an adhesive as much as possible.

  When the adherend is glass, heat cracking causes a problem because the glass expands and contracts due to heat. In the sheet according to the present invention, since the porous foam layer 110 has high stretchability, the heat-induced stretch of the glass is absorbed, so that thermal cracking is less likely to occur.

  Here, the porous foam layer 110 according to the present embodiment is an aqueous dispersion (emulsion) containing a water-dispersible resin as a dispersoid, water or a mixture of water and a water-soluble solvent as a dispersion medium, and a foaming agent. The aqueous liquid medium (emulsion composition) containing an anionic surfactant as an aqueous solution is foamed using a mechanical floss method to form a foam, and the foam is cured by the step of The specific manufacturing method of the quality foam layer 110 will be described later).

  The porous foam layer 110 according to the present embodiment has adhesive strength, material strength, and followability. Due to the properties, it is possible to attach smooth glass surfaces, SUS plates, etc. naturally to wallpaper etc. with surface-treated glass surfaces and uneven surfaces, and to use them repeatedly without material destruction. Become. Moreover, from the material mentioned later, adhesiveness and UV cutability will be exhibited over the whole porous foam layer 110, and it will be excellent in light-shielding property and UV cutability. Moreover, by setting it as the structure which does not fully light-shield, light can be obtained indoors, without peeling the sheet | seat which concerns on this invention, if there exists sunlight.

  Furthermore, according to the porous foam layer 110 which concerns on this form, heat insulation can be exhibited over the whole porous foam layer 110 from the below-mentioned material, and it should be excellent in heat insulation.

<Thickness>
The thickness of the porous foam layer 110 according to the present embodiment can be appropriately designed depending on the application and necessary properties, but is preferably 0.5 mm to 2.0 mm. More preferably, it is 1.0 mm to 2.0 mm. Within the range, the followability to the uneven surface is further improved when the pressing load is applied.

<Density>
The following cell structure can be evaluated by measuring the density of the porous foam layer 110 according to the present embodiment. The higher the density, the smaller the average cell diameter tends to be, while the lower the density, the more flexible. Density can be measured by calculating the weight per unit volume. The density [kg / m ³ ] is preferably 150 to 300 [kg / m ³ ], and more preferably 200 to 250 [kg / m ³ ]. If it is 150 [kg / m < ³ >] or more, adhesive strength and delamination strength will become more sufficient. Moreover, if it is 300 [kg / m ³ ] or less, it has sufficient flexibility, and the followability to the uneven surface is increased, and the expansion and contraction of the adherend having elasticity such as glass is more absorbed. It is.

<Cell structure>
The porous foam layer 110 according to the present embodiment has a semi-open cell structure. By setting it as such a structure, adhesion degree can be further given to the adhesiveness of the raw material which concerns on this invention by a sucker effect. As a result, it does not have an adhesive layer, has self-adhesiveness, and is less likely to cause air accumulation and can be easily removed if it occurs.

(Semi-continuous cell structure)
The semi-continuous cell structure is a structure in which pores (holes) of adjacent cells are smaller than open cells, and unlike closed cells, the cells have small pores. By measuring air permeability, it can be evaluated whether it is a semi-open cell structure. The air permeability is measured according to JIS L 1096 A as described above, using a Frazier type air permeability tester. If the air permeability is 2 [ml / cm ² / s] or more and less than 80 [ml / cm ² / s], it can be said to be a semi-continuous cell structure. The air permeability is preferably 5 to 70 [ml / cm ² / s], more preferably 10 to 60 [ml / cm ² / s], and 20 to 50 [ml / cm ² / s] It is further preferred that Moreover, the confirmation method of semi-open cell structure can be confirmed also by the photograph of a cross section similarly to the calculation method of the following average cell diameter. The cross-sectional SEM photograph was shown in FIG. The center is a SEM photograph of the semi-open cell structure according to the present embodiment.

  The semi-continuous cell structure is a structure in which the pores (holes) between adjacent cells are smaller compared to the open cells, and unlike the closed cells, the cells have small pores, and the structure is flexible compared to the structure of only the closed cells. Even when the material is brought into close contact with the adherend, it is possible to create an escape way for the air, and the followability becomes high. On the contrary, when compared with the structure of only the open cell, the surface in contact with the adherend becomes large, and a strong suction effect can be exhibited, and the adhesive strength becomes high.

(Average cell diameter and cell diameter distribution)
The average cell diameter of cells in the cross section of the porous foam layer 110 is preferably 30 to 200 μm, more preferably 50 to 150 μm, and still more preferably 70 to 100 μm. The reason is that if it is 200 μm or less, the surface in contact with the adherend becomes large. It is because the sucker effect of a cell can be expected by being 30 micrometers or more. In addition, as a measuring method of an average cell diameter, it shall follow the following method.

  First, a photograph of the cross section of the porous foam layer 110 is taken using a scanning electron microscope (SEM, VHXD-500 manufactured by Keyence Corporation). Then, each bubble (cell) diameter is measured using image processing software Image-Pro PLUS (made by Media Cybernetics, 6.3 ver). More specifically, the SEM image is read, and the contrast is adjusted in order to recognize bubbles (cells) in the contrast. Next, the shape of the foam (cell) is read by image processing (it is not a perfect circle but the shape is recognized as it is). Next, "diameter (average)" is selected as a measurement item. Next, the diameter of each bubble (cell) is calculated by measuring the diameter passing through the center of gravity of the object in steps of 2 degrees and averaging the measured values.

(Distribution of bubble (cell) diameter)
Further, in the cross-sectional photograph, air bubbles of 70% or more are preferably within ± 50 μm of the average diameter, more preferably within ± 30 μm, and particularly preferably within ± 20 μm. The reason is that if there is no variation, material breakage is unlikely to occur at the location of large air bubbles, and the delamination strength becomes strong. Moreover, it is because the adhesive strength by a sucker effect is stably obtained.

<Material>
The material (material) of the porous foam layer 110 will be described in detail in the manufacturing method described later.

«First Layer ・ Second Layer»
As described above, the sheet according to the present embodiment has the “first layer” or the “first layer + the second layer” on the porous foam (which may have other layers). May be The first layer and / or the second layer is, for example, a role of maintaining the size and shape of the sheet when assuming (1) repeated attachment and detachment, etc. (2) workability in application (for example, The role of improving air release when there is an air pool when attached to an adherend, etc., (3) functions on its own (eg, heat insulation layer, water holding layer, further, It plays a role (for example, when the first layer is a surface layer) having a function of a surface print layer, a resin mirror layer or the like as described later. The first layer and the second layer may be known layers and are not particularly limited.

  In the case of providing the "first layer" or the "first layer + second layer", it is preferable that at least one layer has an expansion ratio lower than that of the porous foam layer as described above. . With such a configuration, the sheet according to the present invention can be attached to the adherend without wrinkles. Further, regardless of the expansion ratio of the surface layer, the porous foam layer absorbs the expansion and contraction due to the heat of the adherend such as glass, so that thermal cracking does not occur even if it is applied indoors. In addition, although an expansion-contraction rate is mentioned later in detail, it measures based on JISK6251.

  The first layer and / or the second layer can be a single layer structure or a multilayer structure.

<Material>
The materials (materials) of the first layer and / or the second layer will be described in detail in the manufacturing method described later.

«Functional layer»
As described above, in the sheet according to the present embodiment, it is preferable that the porous foam layer, any one of the first layer and the second layer, or a layer obtained by arbitrarily combining them is a functional layer. For example, in the case of FIG. 1, the porous foam layer itself is a functional layer, in the case of FIG. 2, the first layer (or porous foam layer) is a functional layer, in the case of FIG. Two layers (or porous foam layer, first layer, porous foam layer + first layer, porous foam layer + second layer, first layer + second layer) are functional layers A certain aspect can be mentioned. Hereinafter, an example of the function of the functional layer will be described. However, the example is only an example.

<Printing layer>
The printing layer is, for example, a layer in which printing (for example, a picture, a pattern, characters) is applied to the front and back (for example, when the layer is transparent), inside (for example, when the layer is transparent), and the whole. is there. In this case, (1) a layer which can be printed as a functional layer (for example, the second layer in FIG. 3) may be separately provided, or (2) a first layer (for example, the embodiment of FIG. 1 or the porous foam layer 110 (eg, the embodiment of FIG. 1, the embodiment of the porous foam layer visible in FIG. 2, the embodiment of the porous foam layer visible in FIG. 3). ) May be printed on itself. Here, when printing on the first layer or the second layer, examples of the material include a resin film, a paper material, and the like.

<Reflective layer>
The reflective layer is a layer that reflects light (for example, radio wave, infrared light, visible light, ultraviolet light, radiation, and the like), sound, and the like. For example, in the reflective layer, the mirror layer is a layer that totally or at least partially reflects visible light. The mirror layer is obtained, for example, by depositing and laminating a vacuum deposition plated layer on a transparent resin layer, film, or plate (for example, a resin mirror layer). The mirror layer functions as a mirror in the case of substantially total reflection, and as a magic mirror in the case of partial reflection (partial transmission). One example of a method of manufacturing a resin mirror layer is a method of forming a silver film by spraying aluminum particles onto, for example, a PET resin film (vacuum vapor deposition plating). The resin mirror layer may be provided with a function as the surface print layer.

<White board>
A layer having a function as a white board can also be provided on the porous foam layer 110 as a functional layer. Since the porous foam layer 110 is bonded and adhered to an adherend (for example, a glass window or wallpaper), it is possible to stick a white board to the adherend without interposing a magnet, a fixture, or the like.

[Production method]
The sheet 100 according to the present embodiment is a porous foam layer or a laminate formed by laminating a plurality of layers. Hereinafter, the manufacturing method of a porous foam layer is demonstrated, and the method (the manufacturing method of a laminated body) which laminates | stacks a 1st layer etc. on a porous foam layer next is demonstrated. In addition, when the said sheet | seat is a porous foam layer single-piece | unit, the following "the manufacturing method of a porous foam layer" is read as "the manufacturing method of a sheet", and when the said sheet is a laminated body, the following. The “method for producing a porous foam layer” and the “method for producing a laminate” can be read as “a method for producing a sheet”.

«Method for producing porous foam layer»
In the method for producing the porous foam layer 110 according to the present embodiment, an emulsion composition containing an emulsion and a foaming agent is foamed using a mechanical floss method to form a foam, and the foam is cured. including. The emulsion composition further contains a crosslinking agent. The porous foam layer can be obtained by curing the foam by applying energy to crosslink the resin constituting the emulsion through the crosslinking agent in the step. As a method of producing the porous foam layer 110, the raw material, the composition (the compounding amount) and the process (the specific preparation process) will be described in detail.

  Furthermore, in the method of manufacturing the porous foam layer 110 according to the present embodiment, an amphoteric surfactant may be added to retain the cells. It is because ampholytic surfactant gets in between anionic surfactant as a foaming agent, and is called a booster effect.

<Raw material>
The porous foam layer 110 according to the present embodiment contains, as a raw material, an emulsion, a foaming agent (anionic surfactant), water as a dispersion medium, a crosslinking agent, other additives, etc. The foaming gas will be described in the foaming step).

(Type of emulsion)
At least an acrylic emulsion and an ethylene-vinyl acetate copolymer resin emulsion are used as an emulsion raw material of the emulsion composition used when producing the porous foam layer 110 according to the present embodiment.

  For the emulsion of the present invention, an acrylic emulsion is used because it is excellent in adhesive strength, lightness and heat insulation. And, since the material strength of the acrylic emulsion alone is weak, the ethylene vinyl acetate copolymer resin emulsion is added in order to improve the material strength and further increase the adhesive strength. It is understood that, by doing this, it is possible to increase the delamination strength with respect to high adhesive strength, so that it is possible to produce a foam having a semi-open cell structure having self-adhesive strength that is unlikely to cause material breakage.

  Other emulsions may be used as long as the above two emulsions are used. Other examples of the emulsion contained include urethane emulsions, vinyl chloride emulsions, epoxy emulsions and the like. By using a urethane emulsion, the material strength can be further imparted, and it is particularly suitable when the adherend is a tacky glass or the like. In addition, the urethane resin foam obtained is excellent in flexibility and low in compressive residual strain.

· Acrylic emulsion As a process for producing an aqueous dispersion of acrylic resin (acrylic emulsion), for example, (meth) acrylic acid ester monomer in the presence of a polymerization initiator, and, if necessary, an emulsifier and a dispersion stabilizer Can be obtained by copolymerizing a mixture of other polymerizable monomers copolymerizable with these monomers, if necessary. Two or more acrylic emulsions may be used in combination.

  Examples of the polymerizable monomer that can be used for the preparation of the above-mentioned acrylic emulsion include methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, butyl (meth) arlylate, (meth) acrylate ) Hexyl acrylate, heptyl (meth) acrylate, octyl (meth) acrylate, octadecyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, cyclohexyl (meth) acrylate, nonyl (meth) acrylate ( (Meth) acrylic acid such as dodecyl (meth) acrylate, stearyl (meth) acrylate, isobornyl (meth) acrylate, dicyclopentanyl (meth) acrylate, phenyl (meth) acrylate, and benzyl (meth) acrylate Ester monomers; acrylic acid, methacrylic acid, β-carboxyethyl ( Ta) Acrylate, 2- (meth) acryloyl propionic acid, crotonic acid, itaconic acid, maleic acid, fumaric acid, itaconic acid half ester, maleic acid half ester, maleic acid anhydride, unsaturated acid having carboxylic acid such as itaconic anhydride Bond-containing monomer; Glycidyl group-containing polymerizable monomer such as glycidyl (meth) acrylate, allyl glycidyl ether; 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, polyethylene glycol mono (meth) A hydroxyl group-containing polymerizable monomer such as acrylate or glycerol mono (meth) acrylate; ethylene glycol di (meth) acrylate, 1,6-hexanediol di (meth) acrylate, neopentyl glycol di (meth) acrylate, trimethylo And propanepropane tri (meth) acrylate, polyethylene glycol di (meth) acrylate, polypropylene glycol di (meth) acrylate, diallyl phthalate, divinyl benzene, allyl (meth) acrylate and the like.

  In addition, when using an emulsifier at the time of preparation of an acryl-type emulsion, a well-known emulsifier etc. may be used.

-Ethylene vinyl acetate copolymer resin emulsion As a manufacturing method of ethylene vinyl acetate copolymer resin emulsion, for example, polyvinyl alcohol etc. is made into a protection colloid, cellulose derivatives such as hydroxyethyl cellulose, surfactants etc, are used together as an emulsifying dispersant Can be obtained by copolymerizing ethylene and a vinyl acetate monomer by an emulsion polymerization method.

  The ethylene-vinyl acetate copolymer resin emulsion may be obtained, for example, by further copolymerizing a vinyl monomer having a functional group such as a carboxyl group, an epoxy group, a sulfonic acid group, a hydroxyl group, a methylol group or an alkoxy acid group. Good.

  As the ethylene-vinyl acetate copolymer resin emulsion, it is preferable to use at least two ethylene-vinyl acetate copolymer resin emulsions described later. By adjusting the blending amount of each ethylene vinyl acetate copolymer resin emulsion, its flexibility and material strength can be adjusted, and the desired function of the present invention can be realized.

-Urethane emulsion As a preparation method of the water dispersion (urethane emulsion) of urethane resin, the following method (I)-(III) can be illustrated.
(I) An organic solvent solution or an organic solvent dispersion of a urethane resin having a hydrophilic group obtained by reacting an active hydrogen-containing compound, a compound having a hydrophilic group, and a polyisocyanate, as necessary, neutralization A method of mixing an aqueous solution containing an agent to obtain a urethane resin emulsion.
(II) An active hydrogen-containing compound, a compound having a hydrophilic group, and a terminal isocyanate group-containing urethane prepolymer having a hydrophilic group obtained by reacting a polyisocyanate are mixed with an aqueous solution containing a neutralizing agent Alternatively, after a neutralizing agent is added to the prepolymer in advance, water is mixed and dispersed in water, and then reacted with a polyamine to obtain a urethane resin emulsion.
(III) A compound having an active hydrogen-containing compound, a compound having a hydrophilic group, and a terminal isocyanate group-containing urethane prepolymer having a hydrophilic group obtained by reacting a polyisocyanate, mixed with an aqueous solution containing a neutralizing agent and a polyamine Alternatively, after adding a neutralizing agent to the prepolymer in advance, an aqueous solution containing a polyamine is added and mixed to obtain a urethane resin emulsion.

  Examples of the polyisocyanate used in the preparation of the urethane resin include 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, m-phenylene diisocyanate, p-phenylene diisocyanate, 4,4'-diphenylmethane diisocyanate, 2,4 ' -Diphenylmethane diisocyanate, 2,2'-diphenylmethane diisocyanate, 3,3'-dimethyl-4,4'-biphenylene diisocyanate, 3,3'-dimethoxy-4,4'-biphenylene diisocyanate, 3,3'-dichloro-4 1,4'-biphenylene diisocyanate, 1,5-naphthalene diisocyanate, 1,5-tetrahydronaphthalene diisocyanate, tetramethylene diisocyanate, 1,6-hexamethylene diisocyanate, Decamethylene diisocyanate, trimethylhexamethylene diisocyanate, 1,3-cyclohexylene diisocyanate, 1,4-cyclohexylene diisocyanate, xylylene diisocyanate, tetramethyl xylylene diisocyanate, hydrogenated xylylene diisocyanate, lysine diisocyanate, isophorone diisocyanate, 4,4 Examples thereof include '-dicyclohexylmethane diisocyanate, 3,3'-dimethyl-4,4'-dicyclohexylmethane diisocyanate and the like. Moreover, in the range which does not impair the effect of invention, you may use together the polyisocyanate more than trivalence.

  Further, examples of the compound having a hydrophilic group include polyester polyols, polyether polyols, polycarbonate polyols, polyacetal polyols, polyacrylate polyols, polyesteramide polyols, polythioether polyols, and polyolefin polyols such as polybutadiene. These high molecular weight compounds may be used in combination of two or more. Known polyester polyols may be used.

  In the above methods (I) to (III), an emulsifying agent may be further used as long as the effects of the invention are not impaired. Such emulsifiers include, for example, nonionic emulsifiers such as polyoxyethylene nonyl phenyl ether, polyoxyethylene lauryl ether, polyoxyethylene styrenated phenyl ether, polyoxyethylene sorbitol tetraoleate; fatty acid salts such as sodium oleate, alkyl Anionic emulsifier such as sulfuric ester, alkyl benzene sulfonate, alkyl sulfo succinate, naphthalene sulfonate, alkane sulfonate sodium salt, alkyl diphenyl ether sulfonate sodium salt; polyoxyethylene alkyl sulfate, polyoxyethylene alkyl phenyl sulfate Etc. can be exemplified.

(Physical properties of emulsion)
The physical properties of the acrylic emulsion and the ethylene-vinyl acetate copolymer emulsion used in the present invention will be described below.

· Viscosity (mPa · s)
The viscosity is measured by a Brookfield viscometer (25 ° C.).

  The viscosity of the acrylic emulsion is preferably 5,000 to 20,000 mPa · s. The viscosity is more preferably 8,000 to 15,000 mPa · s. If the viscosity is 5,000 or more, the foam holding power at the time of molding is sufficient, finer cells can be formed, and the adhesive strength tends to be stronger. On the other hand, if the viscosity is 20,000 or less, the shear force on the raw material can be reduced at the time of molding, so that it is possible to prevent the formation of strained cells, and a more sufficient adhesive strength can be obtained.

  The two ethylene-vinyl acetate copolymer emulsions used as the ethylene-vinyl acetate copolymer resin emulsion described above preferably have mutually different viscosities. The reason for this is presumed to be that the stirring efficiency of the ethylene-vinyl acetate copolymer resin emulsions is significantly increased by the difference in viscosity of the two ethylene-vinyl acetate copolymer resin emulsions. It is thought that by increasing the stirring efficiency, the vinyl acetate copolymer resin is uniformly disposed, and more strong adhesive strength and material strength can be exhibited.

  More specifically, the stirring efficiency is considered to be one of the important factors in the foam formation in the mechanical frothing process. The increase in the stirring efficiency makes it possible to form the foam in the raw material finer and more uniformly. It is thought that the adhesive strength with respect to a to-be-adhered body improves because the adhesion area with respect to a to-be-adhered body rises by this. It is also presumed that this also affects the strong suction cup effect brought about by the fine cells.

  Among these two ethylene vinyl acetate copolymer emulsions, the viscosity of one ethylene vinyl acetate copolymer emulsion is preferably 2,000 to 4,000 mPa · s, and 2,000 to 3,000 mPa · s. It is more preferable that The viscosity of the other ethylene vinyl acetate copolymer emulsion is preferably 500 to 1,500 mPa · s lower than the viscosity of the one ethylene vinyl acetate copolymer emulsion, and 800 to 1,300 mPa · s lower. More preferable. When the viscosity of the two ethylene vinyl acetate copolymer emulsions is within these ranges, the above-mentioned strong adhesive strength and material strength can be exhibited.

・ Glass transition temperature (Tg)
The glass transition temperature is raised by 25 ° C. to 200 ° C., 2 ° C./min, 1 Hz in the procedure according to JIS-K7198 with a dynamic viscoelasticity device DMA (DMS 6100 manufactured by SII Nano Technology Co., Ltd.) The peak value of tan δ at the time of measurement by is taken as the glass transition temperature.

  The two ethylene-vinyl acetate copolymer emulsions used as the ethylene-vinyl acetate copolymer resin emulsion preferably have mutually different glass transition temperatures. Of the two ethylene vinyl acetate copolymer emulsions, the glass transition temperature of one ethylene vinyl acetate copolymer emulsion is preferably -30 ° C to 30 ° C, and -25 ° C to 25 ° C. More preferable. The glass transition temperature of the other ethylene vinyl acetate copolymer emulsion (the glass transition temperature thereof is preferably 5 ° C. or more lower than the glass transition temperature of the one ethylene vinyl acetate copolymer emulsion, and more preferably 5 to 70 ° C. .

  Moreover, it is preferable that the glass transition temperature of an acryl-type emulsion and the glass transition temperature of an ethylene vinyl acetate copolymer emulsion are all -10 degrees C or less. This is because the acrylic resin and the ethylene-vinyl acetate copolymer tend to have a high hardness and a reduced adhesion at the time of use at a low temperature.

Average particle diameter The average particle diameter is measured by a laser diffraction particle size distribution analyzer (LA-500 manufactured by Horiba, Ltd.), and the obtained median diameter (particle diameter corresponding to 50% of the cumulative distribution, 50%) Let particle size be an average particle size. In addition, the average particle diameter of two or more types of emulsions referred to in the present specification and claims is the weight ratio (blending) of each emulsion (solid content) blended to the average particle diameter of each of the measured emulsions. It is calculated by multiplying the weight of one emulsion to be added / the sum of the weights of all emulsions and then summing the values.

  The average particle diameter of the ethylene-vinyl acetate copolymer emulsion is preferably 1.0 μm or less. When the average particle diameter of the ethylene-vinyl acetate copolymer emulsion is 1.0 μm or less, it is expected that the stirring efficiency of the ethylene-vinyl acetate copolymer emulsion and the acrylic emulsion significantly increases. As described above, the acrylic resin and the ethylene-vinyl acetate copolymer resin are uniformly mixed and uniformly disposed by the increase of the stirring efficiency, thereby exhibiting stronger adhesive strength and material strength. It is because it is thought that it is possible. The lower limit value of the average particle diameter of the ethylene-vinyl acetate copolymer emulsion is not particularly limited, and is, for example, 0.01 μm.

  Moreover, it is preferable that the difference of the average particle diameter of said 2 types of ethylene vinyl acetate copolymer emulsions is 0.1-0.5 micrometer. When the difference in average particle size is within the above range, a larger bonding area is formed on the bonding surface.

Others Regarding ethylene vinyl acetate copolymer emulsion, at least two parameters of viscosity, glass transition temperature and average particle diameter of one ethylene vinyl acetate copolymer emulsion (namely, viscosity and glass transition temperature, viscosity and average particle diameter, It is preferred that the glass transition temperature and the average particle size, and the viscosity, the average particle size and the glass transition temperature) be smaller than that of the other.

  With regard to acrylic emulsions, those which are fillerless are preferred. The reason for this is presumed to be that the reduction in hardness (impartation of flexibility) by fillerlessness can be realized, and the followability to the adherend can be further improved.

(Dispersion medium)
In the present embodiment, as a dispersion medium of the emulsion composition, water is an essential component, but a mixture of water and a water-soluble solvent may be used. The water-soluble solvent is, for example, alcohols such as methyl alcohol, ethyl alcohol, isopropyl alcohol, ethyl carbitol, ethyl cellosolve, butyl cellosolve, polar solvents such as N-methylpyrrolidone, etc., and one or more of them are used. A mixture of or the like may be used.

(Foating agent (anionic surfactant))
Anionic surfactant (foaming anionic surfactant) functions as a foaming agent of the emulsion composition.

  Specific examples of the anionic surfactant include sodium laurate, sodium myristate, sodium stearate, ammonium stearate, sodium oleate, potassium oleate soap, castor oil potassium soap, coconut oil potassium soap, lauroyl sarcosine sodium, Myristoyl sarcosine sodium, oleyl sarcosine sodium, cocoyl sarcosine sodium, coconut oil alcohol sodium sulfate, polyoxyethylene lauryl ether sodium sulfate, sodium alkyl sulfosuccinate, sodium lauryl sulfoacetate, sodium alkyl benzene sulfonate, sodium α-olefin sulfonate etc. Of these, sodium alkyl sulfosuccinate is particularly preferred.

  Here, the anionic surfactant used in the present embodiment is preferably 10 or more, more preferably 20 or more, in order to facilitate dispersion in the emulsion composition. It is particularly preferable that the above is true.

・ HLB
In the present invention, the HLB value means a hydrophilic-hydrophobic balance (HLB) value, which is determined by the Oda method. How to determine the HLB by the Oda method is described in “Introduction to New Surfactants”, pp. 195 to 196 and March 20, 1957, published by Tatsuhiro Oda, “A synthesis of surfactants and its application”, No. 492. It is described on page 502, and it can be determined by HLB = (inorganic / organic) × 10.

(Ampholytic surfactant)
In the porous foam layer 110 according to the present embodiment, by using an amphoteric surfactant in addition to the anionic surfactant, the cells become fine and uniform.

  In particular, when an anionic surfactant and an amphoteric surfactant are used in combination, the charges of the hydrophilic groups of the anionic surfactant molecules repel each other, while the anionic surfactant molecules maintain a certain distance. In addition, air bubbles can be further stabilized and the size of the air bubbles can be reduced by interposing the electrically neutral, double-sided active agent between the anionic surfactant molecules. For this reason, delamination strength can be improved. Therefore, it is preferable to use an anionic surfactant and an amphoteric surfactant in combination.

  The amphoteric surfactant which can be used in the present invention is not particularly limited, and amphoteric surfactants such as amino acid type, betaine type and amine oxide type can be used. Betaine-type amphoteric surfactants are preferred because of the higher effect described above. Further, from the viewpoint of the ease of entry of the anionic surfactant between the molecules, those of C10 to 12 are preferred.

  Examples of amino acid-type amphoteric surfactants include N-alkyl or alkenyl amino acids or salts thereof. In the N-alkyl or alkenyl amino acid, an alkyl group or an alkenyl group is bonded to a nitrogen atom, and one or two "-R-COOH" (wherein R represents a divalent hydrocarbon group, preferably And an alkylene group, particularly preferably having 1 to 2 carbon atoms. In the compound in which one “—R—COOH” is bonded, a hydrogen atom is further bonded to the nitrogen atom. One "-R-COOH" is referred to as a mono compound, and two are referred to as a di compound. As the amphoteric surfactant according to the present invention, any of these mono- and di-bodies can be used. In the N-alkyl or alkenyl amino acid, the alkyl group and the alkenyl group may be linear or branched. Specifically, as the amino acid type amphoteric surfactant, lauryl diaminoethyl glycine sodium, trimethyl glycine sodium, cocoyl taurine sodium, cocoyl methyl taurine sodium, lauroyl glutamate sodium, lauroyl potassium glutamate, lauroyl methyl-β-alanine and the like can be mentioned. Be

  Examples of betaine-type amphoteric surfactants include alkylbetaines, imidazoliniumbetaines, carbobetaines, amidocarbobetaines, amidobetaines, alkylamidobetaines, sulfobetaines, amidosulfobetaines, phosphobetaines and the like. Specifically, as a betaine type amphoteric surfactant, lauryl betaine, stearyl betaine, lauryl dimethylaminoacetic acid betaine, stearyl dimethylaminoacetic acid betaine, lauric acid amidopropyl dimethylamino dimethylaminoacetic acid betaine, isostearic acid amidoethyl dimethylaminoacetic acid betaine, Isostearic acid amide propyl dimethylaminoacetic acid betaine, isostearic acid amidoethyl diethylaminoacetic acid betaine, isostearic acid amidopropyl diethylaminoacetic acid betaine, isostearic acid amidoethyl dimethylaminohydroxysulfobetaine, isostearic acid amidopropyl dimethylaminohydroxysulfobetaine, isostearic acid ethylamidodiethylamino Hydroxysulfobetaine, isostearic acid amide Ropyldiethylaminohydroxysulfobetaine, N-lauryl-N, N-dimethylammonium-N-propylsulfobetaine, N-lauryl-N, N-dimethylammonium-N- (2-hydroxypropyl) sulfobetaine, N-lauryl- N, N-Dimethyl-N- (2-hydroxy-1-sulfopropyl) ammonium sulfobetaine, laurylhydroxysulfobetaine, dodecylaminomethyldimethylsulfopropylbetaine, octadecylaminomethyldimethylsulfopropylbetaine, 2-alkyl-N-carboxy Methyl-N-hydroxyethylimidazolinium betaine (2-lauryl-N-carboxymethyl-N-hydroxyethylimidazolinium betaine 2-stearyl-N-carboxymethyl-N-hydroxyl Betaine and the like), coconut oil fatty acid amidopropyl betaine, coconut oil fatty acid amide propyl hydroxy sultaine and the like.

  Examples of amine oxide type amphoteric surfactants include lauryldimethylamine-N-oxide, oleyldimethylamine-N-oxide and the like.

  Among the amphoteric surfactants described above, it is preferable to use a betaine-type amphoteric surfactant in the method for producing the porous foam layer 110 according to the present invention, and among betaine-types, alkyl betaines and imidazolinium betaines are preferable. And carbobetaine are particularly preferred. Examples of alkyl betaines usable in the present invention include stearyl betaine and lauryl betaine, and examples of imidazolinium betaines include 2-alkyl-N-carboxymethyl-N-hydroxyethylimidazolinium betaine and the like. .

(Crosslinking agent (hardening agent))
By using a crosslinking agent (hardening agent), the strength of the porous foam layer 110 according to the present embodiment can be improved.

  Such a crosslinking agent is not particularly limited, and may be added in a necessary amount according to the use and the like. Examples of the crosslinking method using a crosslinking agent include physical crosslinking, ionic crosslinking, and chemical crosslinking. The crosslinking method can be selected according to the type of water-dispersible resin. As a crosslinking agent, a known crosslinking agent can be used, and a resin compounding system containing an epoxy-based crosslinking agent, a melamine-based crosslinking agent, an isocyanate-based crosslinking agent, a carbodiimide-based crosslinking agent, an oxazoline-based crosslinking agent, etc. An appropriate amount can be used depending on the type of group and the amount of functional group. In order to improve adhesion strength, tack strength and delamination strength, epoxy-based crosslinking agents and isocyanate-based crosslinking agents are preferred. Isocyanate-based and epoxy-based crosslinking agents can prevent material destruction of adherends and porous foams by increasing the material strength. Among them, aliphatic isocyanates are more preferable. Two or more of these crosslinking agents may be used in combination.

(Other additives)
As another additive, a surfactant (emulsifier) for water-dispersible resin dispersion may be added.

· Surfactant for water dispersible resin dispersion The surfactant for water dispersible resin dispersion according to the present embodiment is a surfactant for dispersing a water dispersible resin (unlike anionic surfactants, It does not have to have the effect as a foaming agent). Such surfactant may be appropriately selected according to the water dispersible resin to be selected.

<Composition>
(Blending amount and blending ratio of each raw material)
As a compounding quantity of water dispersible resin (solid content) with respect to a liquid medium, 30-80 weight part is preferable with respect to 100 weight part of liquid media. By setting it as such a range, the effect that a stable foam can be shape | molded is acquired.

· Blending ratio in emulsion composition Regarding the blending amount in the emulsion composition, the weight ratio of ethylene vinyl acetate copolymer emulsion (solid content) to acrylic emulsion (solid content) in the emulsion composition (ethylene vinyl acetate co The polymer emulsion / acrylic emulsion) is preferably 0.05 to 1.70, and more preferably 0.10 to 0.90. It is more preferable that it is 0.20-0.75. By setting it in such a range, it is possible to further follow the adherend and adhere more strongly to the adherend in terms of adhesive strength, hardness (flexibility) and material strength. In addition, even in repeated use, sufficient material strength can be exhibited. In addition, the component which comprises "solid content" of the emulsion said to this specification and a claim is a component which remove | eliminated the dispersion medium from the emulsion. Specifically, in addition to the resin, it contains a surfactant, a filler and the like.

  It is preferred to contain more than 10% by weight and up to 90% by weight of the acrylic emulsion, based on the total weight of the emulsion. The content is more preferably 20% by weight or more and 80% by weight or less and still more preferably 30% by weight or more and 75% by weight or less.

  Furthermore, it is preferable to contain 10% by weight or more and less than 90% by weight of an ethylene-vinyl acetate copolymer resin emulsion based on the total amount of the emulsion. The content is more preferably 20% by weight to 80% by weight, and still more preferably 25% by weight to 75% by weight. When the content is 90% by weight or more, it is difficult to produce a foam by the mechanical floss method, and flexibility, adhesive strength and tack strength are lost.

  In addition, it is preferable to contain the acrylic emulsion and the ethylene-vinyl acetate copolymer resin emulsion in a total amount exceeding 70% by weight based on the total amount of the emulsion. It is more preferable to contain 80 weight% or more or more.

-Blending ratio in the vinyl acetate copolymer emulsion In the present invention, depending on the application (application) and purpose, it may be necessary to adjust the flexibility, tackiness and material strength in more detail. For example, in order to further conform to the sticking test, in the case of blending the two types of ethylene-vinyl acetate copolymer resin emulsions described above, the ethylene-vinyl acetate copolymer resin emulsion 1 (solid content) Weight ratio {ethylene-vinyl acetate copolymer resin emulsion 1 / (ethylene-vinyl acetate copolymer resin emulsion 1 + ethylene-vinyl acetate copolymer) relative to polymer resin emulsion 1 (solid content) and ethylene-vinyl acetate copolymer emulsion 2 It is preferable to contain 0.25-0.90 by resin emulsion 2)}, and it is more preferable to contain 0.30-0.85.

  Here, the ethylene-vinyl acetate copolymer emulsion 1 refers to at least two parameters of viscosity, glass transition temperature and average particle diameter of ethylene-vinyl acetate copolymer emulsion (ie, viscosity and glass transition temperature, viscosity and average particle diameter, The ethylene vinyl acetate copolymer emulsion is shown that the glass transition temperature and the average particle diameter, and the viscosity, the average particle diameter and the glass transition temperature) are larger than that of the other, while the ethylene vinyl acetate copolymer emulsion 2 Is an ethylene-vinyl acetate copolymer emulsion in which at least two parameters of the viscosity, the glass transition temperature and the average particle diameter of the ethylene-vinyl acetate copolymer emulsion are lower than the other.

  The blending amount of the urethane emulsion may be 0% by weight or more and less than 30% by weight of the urethane emulsion based on the total amount of the emulsion. Furthermore, it is preferable that it is 20 weight% or less. Within this range, the material strength can be increased, and flexibility can be imparted, and the adhesive strength also satisfies the desired properties.

  The blending amount of the anionic surfactant is preferably 1.0 to 10 parts by weight, more preferably 3 to 10 parts by weight, based on 100 parts by weight of the total amount of the emulsion in the emulsion composition. By setting it as such a range, it is easy to make it foam appropriately, and the effect that a fine cell structure can be shape | molded is acquired.

  The blending amount of the amphoteric surfactant is preferably 0.5 to 10 parts by weight, and more preferably 1 to 5 parts by weight based on 100 parts by weight of the total amount of the emulsion in the emulsion composition. By setting it as such a range, it is easy to make it foam appropriately, and the effect that a fine cell structure can be shape | molded is acquired.

Blending ratio of emulsion and crosslinking agent The blending ratio of the crosslinking agent (curing agent) is the weight ratio of the crosslinking agent to the acrylic emulsion (solid content) and the ethylene vinyl acetate copolymer emulsion (solid content) in the emulsion composition The above-mentioned cross-linking agent / (the above-mentioned acrylic emulsion + the above-mentioned ethylene vinyl acetate copolymer emulsion)} is 0.01 to 0.12. It is preferable that it is 0.025-0.05. By setting it in such a range, a foam having a small compressive residual strain can be formed, and the followability to the adherend can be further improved, so that the effect of improving the adhesive strength can be obtained.

-Blending ratio of ethylene vinyl acetate copolymer resin emulsion 2 and a crosslinking agent Furthermore, when blending ethylene vinyl acetate copolymer resin emulsion 2 as ethylene vinyl acetate copolymer resin emulsion, ethylene vinyl acetate copolymer resin The weight ratio of the crosslinking agent to the emulsion 2 (solid content) (crosslinking agent / ethylene vinyl acetate copolymer emulsion 2) is preferably 0.10 to 1.40, and 0.20 to 1.0 Is more preferred. By being in such a range, the followability to the adherend can be improved, so the effect of improving the adhesive strength is more easily obtained.

<Manufacturing method>
In the method for producing the porous foam layer 110 according to the present embodiment, the emulsion composition containing the raw material preparation step, the emulsion and the foaming agent is foamed using a mechanical floss method to form a foam, and the foam is concerned. Curing the body (foaming / curing). The emulsion composition may further contain a crosslinking agent, and the foam may be cured by applying energy to crosslink the resin constituting the emulsion through the crosslinking agent in the step. The respective steps will be described in detail below.

(Raw material preparation process)
In the raw material preparation step, an emulsion composition which is a raw material mixture of the porous foam layer 110 is prepared by mixing the respective raw materials as described above. The mixing method in this case is not particularly limited, and for example, it may be mixed while being stirred in a container such as a mixing tank for mixing the respective components.

(Foaming and curing process)
In the foaming / curing step, a predetermined foaming gas is added to the emulsion composition obtained in the above-mentioned raw material preparation step, and these are sufficiently mixed to form a large number of bubbles in the emulsion composition (foamed emulsion composition ). This foaming and curing step is usually carried out by sufficiently mixing the raw material mixture of the liquid porous foam obtained in the raw material preparation step and the foaming gas with a mixing device such as a mixing head.

-Foaming gas The foaming gas mixed with the emulsion composition in the stirring and foaming steps forms cells (cells) in the porous foam layer 110, and can be obtained by the mixing amount of the foaming gas. The expansion ratio and density of the porous foam layer 110 are determined. In order to adjust the density of the porous foam, it is necessary from the desired density of the porous foam and the volume of the raw material of the porous foam (for example, the inner volume of the mold into which the raw material of the porous foam is injected) The weight of the raw material of the porous foam may be calculated, and the amount of the foaming gas may be determined so as to obtain the desired volume in this weight. In addition, air is mainly used as a kind of gas for foaming, but in addition, inert gases such as nitrogen, carbon dioxide, helium, argon and the like can also be used.

Foaming Method, Foaming Condition As a foaming method used in the method of preparing the porous foam layer 110 according to the present invention, a mechanical floss (mechanical foaming) method is used. The mechanical floss method is a method in which air in the atmosphere is mixed with the emulsion composition to foam by stirring the emulsion composition with a stirring blade or the like. As a stirring apparatus, although the stirring apparatus generally used for a mechanical floss method can be used without a restriction | limiting especially, For example, a homogenizer, a dissolver, a mechanical floss foaming machine etc. can be used. According to this mechanical floss method, it is possible to obtain a porous foam having a density suitable for various applications by adjusting the mixing ratio of the emulsion composition and air. It is possible to use other foaming methods in combination, but when the foaming method using a chemical blowing agent is used in combination, the higher the proportion of closed cells, the higher the density and the loss of flexibility of the porous foam. Unfavorable.

  The mixing time of the emulsion composition and air is not particularly limited, but is usually 1 to 10 minutes, preferably 2 to 6 minutes. The mixing temperature is also not particularly limited, but is usually at normal temperature. In addition, the stirring speed in the above mixing is preferably 200 rpm or more (more preferably 500 rpm or more) to make air bubbles finer, and 2000 rpm or less is preferable (800 rpm or less) to smooth discharge of the foam from the foaming machine. More preferred).

-Formation of foam The emulsion composition (foamed emulsion composition) foamed as described above is, for example, in the form of a sheet or the like adjusted to the desired thickness of the porous foam by a known means such as a doctor knife or doctor roll. Formed into a foam.

Curing As a method for curing the foam, known methods can be used. Although the foam according to this embodiment can be self-crosslinked, the foam may be cured by applying energy to crosslink the resin constituting the emulsion via the crosslinking agent. Although it does not specifically limit as a process of applying energy, For example, a heating process (thermal crosslinking) is mentioned.

  In the heating step, the dispersion medium in the formed foamed emulsion composition is evaporated. The drying method in this case is not particularly limited, and for example, hot air drying may be used. Also, the drying temperature and the drying time are not particularly limited, but may be, for example, about 80 ° C. and about 1 to 3 hours.

  Also, in this heating step, the dispersion medium evaporates from the foam emulsion composition, but the passage when this vapor escapes is communicated from the inside of the porous foam to the outside. Therefore, in the porous foam layer 110 according to the present embodiment, since the passage when the water vapor escapes remains as an open cell, at least a part of the air bubbles present in the porous foam becomes an open cell. Here, when the foaming gas mixed in the stirring / foaming step remains as it is, the resulting porous foam becomes closed cells, and the mixed foaming gas loses steam in this step. If they are communicated, they will be open cells in the obtained porous foam. That is, in the present invention, a part of the cells in the porous foam is an open cell, and the remaining cells are closed cells, resulting in a semi-open cell structure in which open cells and closed cells are mixed.

  When the crosslinking agent is added, in the heating step, the crosslinking (curing) reaction of the raw material is advanced and completed. Specifically, the raw materials are crosslinked by the above-described crosslinking agent to form a cured porous foam. The heating means in this case is not particularly limited as long as the raw material can be sufficiently heated and the raw material can be crosslinked (hardened). For example, a tunnel heating furnace can be used. Also, the heating temperature and heating time may be any temperature and time that can crosslink (cure) the raw material, for example, 80 to 150 ° C. (particularly, about 120 ° C. is preferable) and about 1 hour. .

«Method of forming first and second layers»
Next, a method of forming the first layer (or + second layer) in the embodiment in which the sheet is a laminate will be described.

  The method of forming the first layer (or + second layer) is not particularly limited, and a general method of laminating another layer on one layer can be adopted. For example, a method of casting and curing the porous foam layer 110 on the first layer can be mentioned. By thus directly casting the porous foam layer 110 on another layer, the adhesion between the layers can be enhanced without using an adhesive or the like. In addition, the sheet-like layers may be laminated in a desired order, and they may be laminated by appropriately bonding them with an adhesive or the like and integrating them. Also, after the porous foam layer 110 is formed in advance, a dispersion slurry or the like containing the raw material of the first layer is applied to the porous foam layer 110 directly or through another layer, and the first layer is formed. 120 may be formed, or the like. The second layer is similar. If the first layer is not necessary (ie, only the sheet is a porous foam layer), it may be produced by peeling the surface layer after forming the porous foam layer 110 after once forming the laminate. Good.

  In addition, although the formation method of a 1st layer and a 2nd layer was illustrated above, it can manufacture simply by the method of joining the following raw material to a porous foam layer by a well-known method. Hereinafter, the said raw material is described. For example, it is made of film, paper, synthetic paper, cloth, synthetic resin and the like. These may be used alone or in combination. As the first layer and / or the second layer, for example, films such as polyester film, polypropylene film, polystyrene film, vinyl chloride film, olefin film, polyimide film, synthetic paper, wood free paper, coated paper, art paper, Examples thereof include cast-coated paper, super-cast paper, water-resistant paper, kraft paper, recycled paper, impregnated paper, Kent paper, papers such as thermal paper, and cloths. From the manufacturing method described later, a sheet with low stretchability to which the raw material does not penetrate is preferable.

  As a film material used for the first layer and / or the second layer, for example, polyethylene film (PE film), polyvinyl chloride film (PVC film), polyvinylidene chloride film (PVDC film), polyvinyl alcohol film (PVA) Film), polypropylene film (PP film), polyester film, polycarbonate film (PC film), polystyrene film (PS film), polyacrylonitrile film (PAN film) ethylene vinyl acetate copolymer film (EVA film), ethylene-vinyl alcohol Copolymer film (EVOH film), ethylene-methacrylic acid copolymer film (EMAA film), nylon film (NY film, polyamide (PA) film , Cellophane, ionomer film (IO film), and the like. Various metals and magnetic materials are also applicable as film materials used for the surface layer. These may be used alone or in combination. The film material is not limited to the above example.

  As paper materials used for the first layer and / or the second layer, various kinds of high quality paper, coated paper, foil paper, kraft paper, recycled paper, synthetic paper, impregnated paper, Kent paper, thermal paper, etc. are applicable. . These may be used alone or in combination. The paper material is not limited to the above example.

  The cloth material used for the first layer and / or the second layer can include, for example, cotton, gauze, double gauze, weave, fabric and the like. These may be used alone or in combination. The cloth and the material thereof are not limited to the above examples.

  As a synthetic resin used for the first layer and / or the second layer, phenol resin (PF), epoxy resin (EP), melamine resin (MF), urea resin (urea resin, UF), unsaturated polyester resin (UP), alkyd resin, polyurethane (PUR), thermosetting polyimide (PI) polyethylene (PE) (including high density polyethylene (HDPE), medium density polyethylene (MDPE), low density polyethylene (LDPE), polypropylene (polypropylene) PP), polyvinyl chloride (PVC), polyvinylidene chloride, polystyrene (PS), polyvinyl acetate (PVAc), Teflon (registered trademark) (polytetrafluoroethylene, PTFE), ABS resin (acrylonitrile butadiene styrene resin), AS Resin, acrylic resin (PMMA), polyamide (PA) (Including nylon), polyacetal (POM), polycarbonate (PC), modified polyphenylene ether (m-PPE, modified PPE, PPO), polybutylene terephthalate (PBT), polyethylene terephthalate (PET), glass fiber reinforced polyethylene terephthalate (GF-) PET), cyclic polyolefin (COP), polyphenylene sulfide (PPS), polysulfone (PSF), polyether sulfone (PES), amorphous polyarylate (PAR), liquid crystal polymer (LCP), polyetheretherketone (PEEK) , Thermoplastic polyimide (PI), polyamide imide (PAI) and the like. These may be used alone or in combination. The synthetic resin is not limited to the above example.

As the first layer and / or the second layer, as described above, a sheet such as a film or non-woven fabric can be used as a substrate. The basis weight of the non-woven fabric is, for example, 5 to 100 g / m ² .

[nature]
According to the sheet 100 relating to the present embodiment, it is difficult for air accumulation to be made, and even when it is possible, air can be easily released only by pressing from above. This property can be evaluated by a breathability test because of the semi-open cell structure.

  Moreover, it can be stuck on glass with strong adhesive strength. Glass includes not only one having a smooth surface but also surface-treated glass having irregularities on the surface such as ground glass, frosted glass, template glass and the like. This property can be evaluated by adhesive strength.

  Furthermore, according to the sheet 100 according to the present embodiment, since the porous foam layer has both strong adhesiveness and flexibility, it adheres to wallpaper, etc. having a maximum unevenness of 0.7 mm, for example. be able to.

  Furthermore, when peeling, since it is not applied or impregnated with a pressure-sensitive adhesive, it can be peeled off from the joint without transferring to the adherend (without adhesive residue), so that it can be used repeatedly. Can. Moreover, when it peels off, since material strength is large, it can use repeatedly. The ability to be used repeatedly can be evaluated by the delamination strength.

  In the use for glass, as described above, since the porous foam layer absorbs the thermal expansion and contraction of the glass, thermal cracking does not occur even when applied indoors.

  The sheet 100 according to the present embodiment has a light shielding property. The light shielding property can be evaluated by the solar radiation transmittance and the ultraviolet absorptivity. Moreover, it may have thermal insulation. Thermal insulation can be evaluated by thermal conductivity.

Air permeability Air permeability is evaluated according to the JIS L 1096 A method by a value measured using a Frazier type air permeability tester. When the air permeability is 2 [ml / cm ² / s] or more and less than 80 [ml / cm ² / s], it can be said that the structure is a semi-open cell structure. It is preferable that it is 5 [ml / cm ² / s] or more and less than 70 [ml / cm ² / s], and is 10 [ml / cm ² / s] or more and less than 60 [ml / cm ² / s] Is more preferably 20 [ml / cm ² / s] or more and less than 50 [ml / cm ² / s].

・ Adhesive strength (90 ° peel strength)
Adhesive strength (90 ° peel strength) is based on JIS Z 0237 and punched into 24 mm width × 150 mm foam (porous foam) with single-sided adhesive tape stopped on the surface (one not adhesive surface) to eliminate the influence of elongation Layer) on a 30 mm wide × 200 mm wallpaper (manufactured by Sungetsu Co., Ltd., model number LB-9721), reciprocate twice with a 2 kg roller, press-fit, and leave at room temperature for 24 hours. Thereafter, using an autograph, the test force is measured by pulling up at a speed of 300 mm / min (90 ° peeling), and evaluation is made by setting it as adhesive strength (90 ° peeling strength) (N / 24 mm). The adhesive strength is preferably 0.4 to 2.5 N / 24 mm, more preferably 0.9 to 2.5 N / 24 mm, and still more preferably 1.1 to 2.5 N / 24 mm. . When the adhesive strength is less than 0.5 N / 24 mm, there is a problem that the adhesive strength is weak, and when it exceeds 2.5 N / 24 mm, there is a problem that the material is easily broken. The adhesion and adhesion strength between the porous foam layer and the other layers and other layers is higher than the adhesion and adhesion strength between the porous foam and the target (adherend) on which the porous foam is used. preferable. This is because the porous foam layer 110 can be peeled off from the surface of the object without peeling off the other layers at the time of peeling off, so that repeated use becomes possible.

・ Peeling strength (material strength)
The delamination strength (material strength) is evaluated by measuring the stress when T-peel the sample. Specifically, a foam (porous foam layer) is punched into a width of 12 mm × 150 mm, and a double-sided tape (manufactured by Nitto Denko, product number 5000NS) is attached to both sides of the foam, and a backing film 12 mm wide × 200 mm ( PET film: affixing Toray Industries, Inc., part number S38), reciprocate twice with a 2 kg roller, crimp, and leave in a furnace at 85 ° C. for 24 hours. Thereafter, the backing film was pulled at a speed of 1000 mm / min using an autograph (Model No. AG-X, manufactured by Shimadzu Corp.) and allowed to stand at room temperature for 1 hour or longer (T-peel) test force was measured, It evaluates by setting it as N / 12mm. The interlayer peel strength is preferably 3.0 N / 12 mm or more, more preferably 4.0 N / 12 mm or more, and still more preferably 7.0 N / 12 mm or more. If the delamination strength is less than 3.0 N / 12 mm, there is a problem that the film is broken at the time of peeling, and repeated use can not be performed.

Flexibility: According to JIS K 6254, flexibility is evaluated at 25% compressive load. The stress at the time of crushing is measured at a speed of 1.0 mm / min until the sample of φ 50 (porous foam layer) reaches a thickness of 25% of the original thickness of the sample. The 25% compressive load is preferably 2.0 to 11.0 kPa, and more preferably 3.0 to 7.0 kPa. If the 25% compressive load is within the above range, the adherend will have more sufficient followability even if it has some irregularities.

-Light shielding property The light shielding property is evaluated by the solar radiation transmittance (JIS R 3106) and the ultraviolet absorptivity (ISO 9050). The solar radiation transmittance is preferably less than 40%, more preferably less than 30%. When the solar radiation transmittance is 40% or more, the light shielding property is insufficient. The ultraviolet absorptivity is preferably 80% or more, more preferably 90% or more. When the ultraviolet absorptivity is less than 80%, the ultraviolet absorptivity is insufficient.

Thermal insulation Thermal insulation differs depending on the material and thickness of the porous foam layer. It may be changed as appropriate according to the purpose of use. In addition, a layer may be provided to enhance heat insulation. Thermal insulation can be evaluated by measuring heat conductivity based on JISA1412-1. As a measuring instrument, thermal conductivity measuring apparatus (auto Λ) HC-072 (made by EIKO EIZO Co., Ltd.) is mentioned.

-Sticking test Sticking test evaluates adhesive strength of porous foam layer and its persistence. Specifically, a test is performed on the presence or absence of a drop after the porous foam layer is attached. Create a composite of foam and a flat steel plate (100 cm ² ) and a plate with wallpaper attached to a SUS plate. Then, as shown in FIG. 5A, a 6 kg weight is placed on the SUS plate, wallpaper, foam, and steel plate and left for 30 seconds to make the foam adhere to the wallpaper. After that, as shown in FIG. 5B, stand the wallpaper vertically, attach the hook member to the center of the steel plate, hook the weight 100g, 200g or 300g with the hook in the vertical direction and leave it for 24 hours and check for dropping Can be evaluated by By not falling, the adhesive strength and its persistence sufficient for the present invention will be obtained.

・ Repetitive sticking test The repetitive sticking test evaluates whether the adhesive strength and persistence can be maintained even for repeated use. It can be evaluated by confirming the presence or absence of a drop by the pasting test again after the above-mentioned pasting test is completed. It can be seen that by not falling, the adhesive strength and its persistence sufficient for the present invention can be maintained even in repeated application.

[Use]
The sheet 100 according to the present embodiment is applicable to various applications due to its nature. Examples of such applications include calendars, wallpaper (crosses), dirt / scratch covers, photographic print media, advertising media (prints), warning boards, panels (exhibits etc.) other than those mentioned above. Etc.), seasonal ornaments, toys, puzzles, stress relief goods, place mats, elbow pads, mouse pads, magnet substitutes, pushpin substitutes, double-sided tapes, sticky notes, anti-shift materials, packing materials, glass buffer materials ( Bottles, wine bottles, etc.) and grip buffers. In addition, since it has a light shielding property, it can be widely used for light shielding such as window glass and prevention of privacy violation. In addition, it can be widely used in applications for the purpose of preventing scattering of glass and condensation.

  Furthermore, because of the heat insulating property, it can be widely used in applications intended for heat insulation. In this case, as described above, the heat insulation may be enhanced.

  Next, the present invention will be described more specifically by Examples and Comparative Examples, but the present invention is not limited by these examples.

[material]
«Porous foam material»
First, in the present example and the comparative example, the following raw materials were used as a raw material of the porous foam.
<Water-dispersible resin>
-Acrylic emulsion 1:
Acrylonitrile, acrylic acid alkyl ester, itaconic acid copolymer, pH 9, solid content 60%, viscosity 12,000 mPa · s, average particle diameter 0.2 μm, Tg −20 ° C.
-Acrylic emulsion 2 (fillerless):
Ethyl acrylate, methyl methacrylate copolymer, pH 9, solid content 54%, viscosity 10, 500 mPa · s, average particle diameter 0.2 μm, Tg-20 ° C
· Ethylene vinyl acetate copolymer resin emulsion 1:
Ethylene-vinyl acetate copolymer resin emulsion (trade name: S-410 HQ, manufactured by Sumika Chemtex Co., Ltd.), pH 8.5, solid content 55%, viscosity 2,500 mPa · s, average particle diameter 0.9 μm, Tg-18 ° C.
· Ethylene vinyl acetate copolymer resin emulsion 2:
Ethylene-vinyl acetate copolymer resin emulsion (trade name: S-950HQ, manufactured by Sumika Chemtex Co., Ltd.) pH 8.5, solid content 53%, viscosity 1,300 mPa · s, average particle diameter 0.6 μm, Tg-30 ° C.
<Foaming agent>
・ Anionic surfactant 1
Sodium alkyl sulfosuccinate, pH 9.4, solid content 30%, HLB 39.7
・ Anionic surfactant 2
Alkyl betaine, fatty acid alkaminol amide, diethanolamine, anionic surfactant mixed system pH 7, solid content 40%
・ Ampholytic foaming agent 3
Alkyl betaine, pH 10, 40% solids
<Crosslinking agent>
· Crosslinking agent Hydrophobic HDI isocyanurate, number of functional groups 3.5

<Porous foam material 1>
Acrylic emulsion 1 and ethylene vinyl acetate copolymer resin emulsion 1 are used as main ingredients, 3 parts by weight of anionic foaming agent 1, 3 parts by weight of anionic foaming agent 2 with respect to 50: 50 parts by weight of each. Then, 1 part by weight of the amphoteric foaming agent 3 and 2.0 parts by weight of the crosslinking agent were mixed to obtain the porous foam raw material 1 (corresponding to Example 1).
<Porous foam material 2-15>
A foam raw material was prepared in the same manner as in the porous foam raw material 1 except that the raw material was blended in the ratio (corresponding to Example 2-15) shown in Tables 1 and 2.
<Porous foam material 16-24>
A foam raw material was prepared in the same manner as in the porous foam raw material 1, except that the raw material was blended at the ratio shown in Table 2 (corresponding to Comparative Example 1-9).

«Base material»
The following were used as a base material which carries a foam.
<Base material>
・ Base 1
PET film (0.038 mm) that has been demolded

Sheet formation
Preparation of Example 1
An inert gas such as air or nitrogen gas is added to the porous foam raw material 1 to foam it by mechanical floss method (foaming condition 100 to 1000 rpm), and after casting on the substrate 1, heat treatment (oven or drying furnace) The sheet according to Example 1 was obtained by carrying out.
Preparation of Example 2-20
A sheet according to Example 2-15 was obtained in the same manner as in Example 1 except that the used porous foam raw material was prepared according to Table 1.
«Comparative Example 1-15»
A sheet (adhesive foam) according to Comparative Example 1-9 was obtained in the same manner as Example 1, except that the used foam raw material was prepared according to Table 2.

[Evaluation test]
Next, measurement and evaluation of the sheets (Examples 1 to 15 and Comparative Examples 1 to 9) were performed. The results are shown in Tables 1-2.

-Appearance The surface of the foam was evaluated visually. Moreover, about the state of the cell, it evaluated from the cross-sectional image of the foam by a scanning electron microscope. When the surface of the foam is broken or there is no surface roughening due to cell union, the cell is uniform if the cell is uniform, "○", some surface roughening, if the cell is rough, 、, the surface is rough, the cell is very rough In the case where the cell was not formed (no foaming), the case was evaluated as "x". Although not shown in the table, the surface of the foam according to the example had uniform cells and no surface damage.

-Bubble structure The foam structure was evaluated by air permeability measurement. If it is 2 [ml / cm ² / s] or more and 80 [ml / cm ² / s], it has a semi-continuous cell structure. Although not shown in the table, the foam according to the example formed a semi-open cell structure.

Thickness Thickness was measured by a thickness gauge.

Density was measured by calculating the weight per unit volume.

-Flexibility According to JIS K 6254, the flexibility was evaluated at 25% compression load. The stress at which 25% of the thickness is crushed (to a thickness of 75%) at a speed of 1.0 mm / min at a speed of 1.0 mm / min is measured.
If the measured stress is "◎" in the case of 2.0 kPa or more and less than 3.0 kPa, "○" in the case of 3.0 kPa or more and less than 7.0 kpa, "△", 2 if it is 7.0 kPa or more and less than 11.0 kPa In the case of less than 0 kPa or 11.0 kpa or more, it was evaluated as "x".

・ Adhesive strength (90 ° peel strength)
Based on JIS Z 0237, punched into 24 mm wide × 150 mm, and removed the single-sided adhesive tape on the surface (not adhesive side) to eliminate the influence of elongation Wallpaper of 30 mm wide × 200 mm (Sangetsu Co., Ltd. It sticks to model number LB-9721), and it reciprocates twice with a 2 kg roller, and it is crimped | bonded, and is left to stand at room temperature for 24 hours. Thereafter, using an autograph, the test force is measured by pulling up at a speed of 300 mm / min (90 ° peeling) to obtain an adhesive strength (90 ° peeling strength) (N / 24 mm). When the adhesive strength (90 ° peel strength) is 1.1 N / 24 mm or more and 2.5 N / 24 mm or less “◎”, the adhesive strength (90 ° peel strength) is 0.9 N / 24 mm or more and 1.1 N / 24 mm or less In the case where the “o” adhesive strength (90 ° peel strength) is 0.4 N / 24 mm or more and 0.9 N / 24 mm or less “Δ”, the adhesive strength (90 ° peel strength) is less than 0.4 N / 24 mm or 2. When exceeding 5 N / 24 mm, it evaluated as "x".

・ Peeling strength (material strength)
According to the test method described above, a foam is punched out to 12 mm wide × 150 mm and a double-sided tape is stuck on both sides of the foam, a 12 mm wide × 200 mm backing film (PET film) is stuck on both sides and reciprocated twice with a 2 kg roller Let stand at 85 ° C. for 24 hours. Then, it is left to stand at room temperature for 1 hour or more, and an autograph is used to measure the test force of pulling the backing film at a speed of 1000 mm / min (T-peel) to obtain a delamination strength (N / 12 mm). When the delamination strength is 7.0 N / 12 mm or more "◎", when the delamination strength is 3.0 N / 12 mm or more and 7.0 N / 12 mm or less "O", the delamination strength is less than 3.0 N / 12 mm The case was evaluated as "x".

-Sticking test The sticking test was done by the test method mentioned above.
The following equipment was used in this test.
・ SUS plate: Futaba Electronics Co., Ltd. make, model number SUS304
-Wallpaper: Sanggetsu Co., Ltd. make, model number LB-9721
-Hook: manufactured by LEC Corporation, model number H-553
Steel plate: area 100 cm ² , weight 80 g, thickness 5.0 mm

  In the evaluation method, no drop was evaluated as ○, and a drop was evaluated as x. In addition, when breakage was seen in a to-be-adhered body or a foam, it was set as x.

If this sticking test passes, the theoretical following condition is satisfied.
(1) 100 g load acceptance in the area ^{100cm 2 (100g / 100cm 2)} ⇒10kg / m 2
(2) at an area 100 cm ² 200 g load pass ^{(200g / 100cm 2) ⇒20kg /} m 2
(3) 300 g load acceptance in the area ^{100cm 2 (300g / 100cm 2)} ⇒30kg / m 2

  The unevenness of the wallpaper (Sangetsu Co., Ltd., model number LB-9721) used for the sticking test is 0.7 mm at maximum (see the cross-sectional photograph in FIG. 6). The photograph of the cross section of the wallpaper was taken using 0.7 mm of the maximum value using a scanning electron microscope (SEM, manufactured by Keyence Corporation, VHXD-500). Then, the uneven | corrugated depth was measured using image process software Image-Pro PLUS (made by Media Cybernetics, 6.3 ver). More specifically, the SEM image was read, and then the shape of the unevenness was read by image processing (the shape was recognized as it is). Next, "distance between two points" was selected as a measurement item. Next, for any 20 convex portions, the distance in the thickness direction of the bottom of the concave portion adjacent to the top of the convex portion was calculated, and the maximum distance was calculated.

Repeated sticking test Repeated sticking test was performed according to the test method described above. Although not shown in the table, it was found that the sheet according to the example in which material failure does not occur maintains its adhesive strength, followability and material strength even in repeated application.

  As an evaluation method, no drop was judged as "o", and with drop it was judged as "x". In addition, although it did not fall, when damage to an adherend or a foam was seen, it was set as "(triangle | delta)."

-Comprehensive judgment Comprehensive judgment was performed about the 25% compression load, material strength, and the evaluation result (the result was shown to Table 1 and 2) of above-mentioned adhesive strength. About the result of said 3 types of evaluation items, total was calculated by making ◎ three points, ○ two points, Δ one point, and x zero. In this case, eight or more points are designated as "AAA", seven points as "AA", six points and five points as "A", four points as "A '", and three or less as "B". These results are shown in Tables 1 and 2.

  As shown in Tables 1 and 2, the example is an evaluation of A 'or more in comprehensive judgment based on the results of adhesive strength, delamination strength, and 25% compressive load, and it is also に お い て in the sticking test (100 g load). The object of the present invention is to achieve the object. In addition, it turned out that the sheet | seat which concerns on this invention can exhibit favorable adhesiveness also with the glass surface which is a smooth surface, and SUS board.

  In addition, on the laminated sheet provided with the PET film on the sheet of Example 8, a laminated sheet provided with the above-described resin mirror layer as a functional layer was prepared as the outermost layer. Similarly, a laminated sheet provided with a white board was prepared. When the said lamination sheet was stuck on a SUS board, a glass surface, surface treatment glass, and a wallpaper, all could be stuck with a favorable adhesion degree, and it could be used as a reflecting mirror or a white board, respectively. Further, it was also found that no drop occurs in the sticking test, and the laminated sheet does not break down the material at the time of the subsequent peeling, and can be repeatedly used.

100 sheet 110 porous foam layer 120 first layer 130 second layer

Claims (15)

A method of producing a sheet having at least a porous foam layer, comprising:
The production method comprises the steps of: foaming an emulsion composition containing the emulsion, a crosslinking agent and a foaming agent using a mechanical floss method to form a foam, and curing the foam.
The emulsion contains an acrylic emulsion and an ethylene vinyl acetate copolymer emulsion,
The weight ratio of the ethylene-vinyl acetate copolymer emulsion (solid content) to the acrylic emulsion (solid content) in the emulsion composition (the ethylene-vinyl acetate copolymer emulsion / the acrylic emulsion) is 0.05 ~ 1.7,
Weight ratio of the crosslinking agent to the acrylic emulsion (solid content) and the ethylene-vinyl acetate copolymer emulsion (solid content) in the emulsion composition {the crosslinking agent / (the acrylic emulsion + the ethylene vinyl acetate copolymer polymer emulsion)} is Ri 0.01 to 0.12 der,
The emulsion composition contains, as the ethylene-vinyl acetate copolymer emulsion, at least two ethylene-vinyl acetate copolymer emulsions,
The method for producing a sheet, wherein the two ethylene vinyl acetate copolymer emulsions have mutually different viscosities (mPa · s) and / or glass transition temperatures . Among the two ethylene vinyl acetate copolymer emulsions, the viscosity of one ethylene vinyl acetate copolymer emulsion is 2,000 to 4,000 mPa · s, and the viscosity of the other ethylene vinyl acetate copolymer emulsion is the one 500~1,500mPa · s lower than the viscosity of the ethylene-vinyl acetate copolymer emulsion, sheet manufacturing method of claim 1, wherein. Of the two ethylene vinyl acetate copolymer emulsions, the glass transition temperature of one ethylene vinyl acetate copolymer emulsion is -30 ° C to 30 ° C, and the glass transition temperature of the other ethylene vinyl acetate copolymer emulsion The method for producing a sheet according to claim 1 or 2 , wherein the temperature is 5 ° C or more lower than the glass transition temperature of the one ethylene-vinyl acetate copolymer emulsion. The sheet manufacturing method according to any one of claims 1 to 3 , wherein an average particle size of the ethylene-vinyl acetate copolymer emulsion is 1.0 μm or less. The sheet manufacturing method according to any one of claims 1 to 4 , wherein a difference between average particle sizes of the two ethylene vinyl acetate copolymer emulsions is 0.1 to 0.5 m. The method for producing a sheet according to any one of claims 1 to 5 , wherein the glass transition temperature of the acrylic emulsion and the glass transition temperature of the ethylene vinyl acetate copolymer emulsion are both -10 ° C or less.   A method of producing a sheet having at least a porous foam layer, comprising:
  A step of foaming the emulsion composition containing the emulsion, the crosslinking agent and the foaming agent using a mechanical floss method to form a foam, and curing the foam;
Including
  The emulsion contains an acrylic emulsion and an ethylene vinyl acetate copolymer emulsion,
  The weight ratio of the ethylene-vinyl acetate copolymer emulsion (solid content) to the acrylic emulsion (solid content) in the emulsion composition (the ethylene-vinyl acetate copolymer emulsion / the acrylic emulsion) is 0.05 ~ 1.7,
  Weight ratio of the crosslinking agent to the acrylic emulsion (solid content) and the ethylene-vinyl acetate copolymer emulsion (solid content) in the emulsion composition {the crosslinking agent / (the acrylic emulsion + the ethylene vinyl acetate copolymer Polymer emulsion)} is 0.01 to 0.12,
  Both the glass transition temperature of the acrylic emulsion and the glass transition temperature of the ethylene vinyl acetate copolymer emulsion are -10 ° C or less
A sheet manufacturing method characterized in that.   The method for producing a sheet according to any one of claims 1 to 7, wherein the sheet further comprises a first layer provided on one side of the porous foam layer.   9. The method of manufacturing a sheet according to claim 8, wherein the sheet further comprises a second layer laminated on the first layer.   The method for producing a sheet according to claim 8 or 9, wherein the first layer or the second layer is a layer having a function as a printing layer, a reflective layer or a whiteboard. A method of producing a sheet having at least a porous foam layer, comprising:
A step of foaming the emulsion composition containing the emulsion, the crosslinking agent and the foaming agent using a mechanical floss method to form a foam, and curing the foam;
Including
The emulsion contains an acrylic emulsion and an ethylene vinyl acetate copolymer emulsion,
The weight ratio of the ethylene-vinyl acetate copolymer emulsion (solid content) to the acrylic emulsion (solid content) in the emulsion composition (the ethylene-vinyl acetate copolymer emulsion / the acrylic emulsion) is 0.05 ~ 1.7,
Weight ratio of the crosslinking agent to the acrylic emulsion (solid content) and the ethylene-vinyl acetate copolymer emulsion (solid content) in the emulsion composition {the crosslinking agent / (the acrylic emulsion + the ethylene vinyl acetate copolymer Polymer emulsion)} is 0.01 to 0.12,
The density of the porous foam layer is 150 to 300 kg / m ³ ,
The thickness of the porous foam layer is 0.5 to 2.0 mm,
The average cell diameter of the porous foam layer is 30 to 200 μm,
The delamination strength of the porous foam layer is 3.0 N / 12 mm or more,
The 25% compressive load of the porous foam layer is 2.0 to 11.0 kPa,
The adhesive strength of the porous foam layer is 0.4 to 2.5 N / 24 mm,
A sheet manufacturing method characterized in that. A sheet having at least a porous foam layer,
The porous foam layer contains an acrylic resin and an ethylene vinyl acetate copolymer resin,
The density of the porous foam layer is 150 to 300 kg / m ³ ,
The thickness of the porous foam layer is 0.5 to 2.0 mm,
The average cell diameter of the porous foam layer is 30 to 200 μm,
The cells of the porous foam layer are formed by mechanical floss method,
The delamination strength of the porous foam layer is 3.0 N / 12 mm or more,
The 25% compressive load of the porous foam layer is 2.0 to 11.0 kPa,
A sheet wherein the adhesive strength of the porous foam layer is 0.4 to 2.5 N / 24 mm.   The sheet according to claim 12, wherein the sheet further comprises a first layer provided on one side of the porous foam layer.   14. The sheet of claim 13, wherein the sheet further comprises a second layer laminated on the first layer.   The sheet according to claim 13 or 14, wherein the first layer or the second layer is a layer having a function as a printing layer, a reflective layer or a whiteboard.